title: Catastrophic alpha quenching alleviated by helicity flux and shear

abstract:
  A new simulation set-up is proposed for studying mean field dynamo action.
The model combines the computational advantages of local cartesian geometry
with the ability to include a shear profile that resembles the sun's
differential rotation at low latitudes. It is shown that in a two-dimensional
mean field model this geometry produces cyclic solutions with dynamo waves
traveling away from the equator -- as expected for a positive alpha effect in
the northern hemisphere. In three dimensions with turbulence driven by a
helical forcing function, an alpha effect is self-consistently generated in the
presence of a finite imposed toroidal magnetic field. The results suggest that,
due to a finite flux of current helicity out of the domain, alpha quenching
appears to be non-catastrophic -- at least for intermediate values of the
magnetic Reynolds number. For larger values of the magnetic Reynolds number,
however, there is evidence for a reversal of the trend and that $\alpha$ may
decrease with increasing magnetic Reynolds number. Control experiments with
closed boundaries confirm that in the absence of a current helicity flux, but
with shear as before, alpha quenching is always catastrophic and alpha
decreases inversely proportional to the magnetic Reynolds number. For solar
parameters, our results suggest a current helicity flux of about 0.001 G^2/s.
This corresponds to a magnetic helicity flux, integrated over the northern
hemisphere and over the 11 year solar cycle, of about 10^{46}Mx^2.


title:
First results with the IOTA3 imaging interferometer: The spectroscopic
  binaries lambda Vir and WR 140

abstract:
  We report the first spatially-resolved observations of the spectroscopic
binaries lambda Vir and WR 140, which includes the debut of aperture-synthesis
imaging with the upgraded three-telescope IOTA interferometer. Using IONIC-3, a
new integrated optics beam combiner capable of precise closure phase
measurement, short observations were sufficient to extract the angular
separation and orientation of each binary system and the component brightness
ratio. Most notably, the underlying binary in the prototypical colliding-wind
source WR 140 (WC7 + O4/5) was found to have a separation of ~13
milli-arcseconds with a position angle consistent with the images of the 2001
dust shell ejection only if the Wolf-Rayet star is fainter than the O star at
1.65 microns. We also highlight lambda Vir whose peculiar stellar properties of
the Am star components will permit direct testing of current theories of tidal
evolution when the full orbit is determined.


title:
Off-equilibrium dynamics of the primordial perturbations in the
  inflationary universe: the O(N) model

abstract:
  Using the O(N) model as an example, we investigate the self-interaction
effects of inflaton on the dynamics of the primordial perturbations. When
taking interactions into account, it is essential to employ a self-consistent
off-equilibrium formalism to study the evolution of the inflationary background
field and its fluctuations with the back-reaction effects. Within the Hartree
factorization scheme, we show that the O(N) model has at least two observable
remains left behind the off-equilibrium processes: the running spectral index
of primordial density perturbations and the correlations between perturbation
modes in phase space. We find that the running of the spectral index is fully
determined by the rate of the energy transfer from the inflationary background
field to its fluctuations via particle creation processes as well as the
dynamics of the background field itself. Furthermore, the amplitude of the
field fluctuations turns out to be scale-dependent due to the off-equilibrium
evolution. As a consequence, the scale-dependence of fluctuations yields a
correlation between the phase space modes of energy density perturbations,
while the one-point function of the fluctuations in each Hartree mode is still
Gaussian. More importantly, the mode-mode correlation of the primordial
perturbations depends upon the dynamics of the self-interaction {\it as well
as} the initial conditions of the inflation. Hence, we propose that the running
spectral index and the correlation between phase-space modes would be two
observable fossils to probe the epoch of inflation, even beyond.


title: X-ray emission from Saturn

abstract:
  We report the first unambiguous detection of X-ray emission originating from
Saturn with a Chandra observation, duration 65.5 ksec with ACIS-S3. Beyond the
pure detection we analyze the spatial distribution of X-rays on the planetary
surface, the light curve, and some spectral properties. The detection is based
on 162 cts extracted from the ACIS-S3 chip within the optical disk of Saturn.
We found no evidence for smaller or larger angular extent. The expected
background level is 56 cts, i.e., the count rate is (1.6 +- 0.2) 10^-3 cts/s.
The extracted photons are rather concentrated towards the equator of the
apparent disk, while both polar caps have a relative photon deficit. The
inclination angle of Saturn during the observation was -27 degrees, so that the
northern hemisphere was not visible during the complete observation. In
addition, it was occulted by the ring system. We found a small but significant
photon excess at one edge of the ring system. The light curve shows a small dip
twice at identical phases, but rotational modulation cannot be claimed at a
significant level. Spectral modeling results in a number of statistically, but
not necessarily physically, acceptable models. The X-ray flux level we
calculate from the best-fit spectral models is 6.8 10^-15 erg/cm^2/s (in the
energy interval 0.1-2keV), which corresponds to an X-ray luminosity of 8.7
10^14 erg/s. A combination of scatter processes of solar X-rays requires a
relatively high albedo favoring internal processes, but a definitive
explanation remains an open issue.


title:
Radio-optical flux behavior and spectral energy distribution of the
  intermediate blazar GC 0109+224

abstract:
  About twenty years of radio observations in five bands (from 4.8 to 37 GHz)
of the BL Lac object GC 0109+224 (S2 0109+22, RGB J0112+227), are presented and
analysed together with the optical data. Over the past ten years this blazar
has exhibited enhanced activity. There is only weak correlation between radio
and optical flares delays, usually protracted on longer timescales in the radio
with respect to the optical. In some cases no radio flare counterpart was
observed for the optical outbursts. The radio variability, characterised by
peaks superposition, shows hints of some characteristic timescales (around the
3-4 years), and a fluctuation mode between the flickering and the shot noise.
The reconstructed spectral energy distribution, poorly monitored at high
energies, is preliminarily parameterised with a synchrotron-self Compton
description. The smooth synchrotron continuum, peaked in the near-IR-optical
bands, strengthens the hypothesis that this source could be an intermediate
blazar. Moreover the intense flux in millimetre bands, and the optical and
X-ray brightness, might suggest a possible detectable gamma-ray emission.


title: The ARGO-YBJ sensitivity to GRBs

abstract:
  ARGO-YBJ is a "full coverage" air shower detector under construction at the
YangBaJing Laboratory (4300 m a.s.l., Tibet, P.R. of China). Its main goals are
gamma-ray astronomy and cosmic ray studies. In this paper we present the
capabilities of ARGO-YBJ in detecting the emission from Gamma Ray Bursts (GRBs)
at energies E>10 GeV.


title: Cepheid calibration of type Ia Supernovae and the Hubble constant

abstract:
  We investigate how a different calibration of the Cepheid Period-Luminosity
(PL) relation taking into account the metallicity corrections, affects the
absolute magnitude calibration of Supernovae (SNe) Ia and, in turn, the
determination of the Hubble constant H_0. We exploit SN Ia light curves from
literature and previously unpublished data, to build the M_B -- Delta m_{15}(B)
relation and we calibrate the zero point by means of 9 type Ia SNe with Cepheid
measured distances. This relation was then used to build the Hubble diagram and
in turn to derive H_0. In the attempt to correct for the host galaxy
extinction, we found that the data seems to suggest a value for the total to
selective absorption ratio, R_B=3.5, which is smaller than the standard value
for our own Galaxy R_B=4.315. Depending on different metallicity corrections
for the Cepheids P-L relation, values of R_B and SN sample selection criteria,
we found that the values of the Hubble constant H_0 is in the range 68--74 km
s^{-1} Mpc^{-1}, with associated uncertainties of the order of 10%. Unpublished
photometry is also presented for 18 SNe of our sample (1991S, 1991T, 1992A,
1992K, 1993H, 1993L, 1994D, 1994M, 1994ae, 1995D, 1995ac, 1995bd, 1996bo,
1997bp, 1997br, 1999aa, 1999dk, 2000cx), which are the results of a long
standing effort for supernova monitoring at ESO - La Silla and Asiago
Observatories.


title:
Does the Lunar Surface Still Offer Value As a Site for Astronomical
  Observatories?

abstract:
  Current thinking about the Moon as a destination has revitalized interest in
lunar astronomical observatories. Once seen by a large scientific community as
a highly enabling site, the dramatic improvement in capabilities for free-space
observatories prompts reevaluation of this interest. Whereas the lunar surface
offers huge performance advantages for astronomy over terrestrial sites,
free-space locales such as Earth orbit or Lagrange points offer performance
that is superior to what could be achieved on the Moon. While astronomy from
the Moon may be cost effective once infrastructure is there, it is in many
respects no longer clearly enabling compared to free-space.


title: Quasar jet emission model applied to the microquasar GRS 1915+105

abstract:
  The true nature of the radio emitting material observed to be moving
relativistically in quasars and microquasars is still unclear. The microquasar
community usually interprets them as distinct clouds of plasma, while the
extragalactic community prefers a shock wave model. Here we show that the
synchrotron variability pattern of the microquasar GRS 1915+105 observed on 15
May 1997 can be reproduced by the standard shock model for extragalactic jets,
which describes well the long-term behaviour of the quasar 3C 273. This
strengthens the analogy between the two classes of objects and suggests that
the physics of relativistic jets is independent of the mass of the black hole.
The model parameters we derive for GRS 1915+105 correspond to a rather
dissipative jet flow, which is only mildly relativistic with a speed of 0.60 c.
We can also estimate that the shock waves form in the jet at a distance of
about 1 AU from the black hole.


title:
Testing for Non-Gaussianity in the Wilkinson Microwave Anisotropy Probe
  Data: Minkowski Functionals and the Length of the Skeleton

abstract:
  The three Minkowski functionals and the recently defined length of the
skeleton are estimated for the co-added first-year Wilkinson Microwave
Anisotropy Probe (WMAP) data and compared with 5000 Monte Carlo simulations,
based on Gaussian fluctuations with the a-priori best-fit running-index power
spectrum and WMAP-like beam and noise properties. Several power
spectrum-dependent quantities, such as the number of stationary points, the
total length of the skeleton, and a spectral parameter, gamma, are also
estimated. While the area and length Minkowski functionals and the length of
the skeleton show no evidence for departures from the Gaussian hypothesis, the
northern hemisphere genus has a chi^2 that is large at the 95% level for all
scales. For the particular smoothing scale of 3.40 degrees FWHM it is larger
than that found in 99.5% of the simulations. In addition, the WMAP genus for
negative thresholds in the northern hemisphere has an amplitude that is larger
than in the simulations with a significance of more than 3 sigma. On the
smallest angular scales considered, the number of extrema in the WMAP data is
high at the 3 sigma level. However, this can probably be attributed to the
effect of point sources. Finally, the spectral parameter gamma is high at the
99% level in the northern Galactic hemisphere, while perfectly acceptable in
the southern hemisphere. The results provide strong evidence for the presence
of both non-Gaussian behavior and an unexpected power asymmetry between the
northern and southern hemispheres in the WMAP data.


title: Relativistic Electrons & Magnetic Fields in Clusters of Galaxies

abstract:
  RXTE and BeppoSAX observations have yielded evidence for the presence of a
secondary power-law spectral component in the spectra of several clusters of
galaxies. This emission in clusters with extended regions of radio emission is
likely to be by relativistic electrons that are Compton scattered by the CMB.
The radio and non-thermal (NT) X-ray measurements yield the values of the
volume-averaged magnetic field and electron energy density in the cluster
extragalactic environment. These directly deduced quantities provide a tangible
basis for the study of NT phenomena in clusters.


title:
Variation of the fine structure constant in QSO spectra from coherent
  dark matter oscillations

abstract:
  We consider the problem of the evolution of the fine structure coefficient
alpha under the assumption that the scalar field coupling to the Maxwell term
satisfies the condition mt>>1 for coherent dark matter oscillations. In this
case we find that the coupling scale f in the leading order coupling
-(phi/4f)F^2 affects the cosmological evolution of alpha according to
ln(alpha/alpha_0) xi(m_{Pl}/f)ln(tanh(t/2 tau)/tanh(t_0/2 tau)). A fit to the
QSO observations by Murphy et al. yields f/xi= 2.12^{+0.58}_{-0.37} 10^5m_{Pl}.
Here m_{Pl} is the reduced Planck mass, and xi^2=rho_phi/rho_m parametrizes the
contribution of phi to the matter density in the universe.


title: Formation and Migration of Trans-Neptunian Objects

abstract:
  Trans-Neptunian objects (TNOs) with diameter d>100 km moving now in not very
eccentric orbits could be formed directly by the compression of large rarefied
dust condensations (with semi-major axes a>30 AU), but not by the accretion of
smaller solid planetesimals. A considerable portion of TNO binaries could be
formed at the stage of compression of condensations. Five years before the
first TNO was observed, we supposed that, besides TNOs formed beyond 30 AU and
moving in low eccentric orbits, there were former planetesimals from the zone
of the giant planets in highly eccentric orbits beyond Neptune. For the present
mass of the trans-Neptunian belt, the collisional lifetime of 1-km TNO is about
the age of the solar system. At the present time TNOs can supply a large amount
of matter to the near-Earth space.


title:
Contaminants in ATCA baselines with shadowing: a case study of cross
  talk in short-spacing interferometers

abstract:
  Interferometric telescopes made of close-packed antenna elements are an
important tool for imaging extended radio sources, specifically structures that
have angular sizes comparable to or even greater than the FWHM of the beams of
the antennas. They have proved useful in observations of cosmic microwave
background anisotropies that require high brightness-sensitivity. However, the
visibilities measured in baselines formed between close antenna elements -- in
particular, between shadowed elements -- of Fourier-synthesis arrays are often
observed to be corrupted. We discuss the multiplicative and additive errors
affecting such short-baseline interferometers.
  As a case study, we have examined the nature of the spurious correlations
between the Cassegrain-type paraboloidal reflectors that are elements of the
Australia Telescope Compact Array. In configurations with geometric shadowing,
the cross talk here appears as an additive component. Analysis of the
characteristics of this cross talk leads us to believe that when these
reflector antennas are in a shadowed configuration, the receivers in the
antenna pair pick up correlated emission from opposite sides of the main
reflector surface of the front antenna. The slots between the panels that make
up the main reflector surface provide the pathway for the coupling across the
reflector surface. This mode of cross talk may be avoided by constructing the
main reflectors of short spacing interferometers as continuous conducting
surfaces.


title: Magnetic Fields in Molecular Clouds

abstract:
  Magnetic fields are believed to play an important role in the evolution of
molecular clouds, from their large scale structure to dense cores, protostellar
envelopes, and protoplanetary disks. How important is unclear, and whether
magnetic fields are the dominant force driving star formation at any scale is
also unclear. In this review we examine the observational data which address
these questions, with particular emphasis on high angular resolution
observations. Unfortunately the data do not clarify the situation. It is clear
that the fields are important, but to what degree we don't yet know.
Observations to date have been limited by the sensitivity of available
telescopes and instrumentation. In the future ALMA and the SKA in particular
should provide great advances in observational studies of magnetic fields, and
we discuss which observations are most desirable when they become available.


title: Photometric Properties of White Dwarf Dominated Halos

abstract:
  Using stellar population synthesis techniques, we explore the photometric
signatures of white dwarf progenitor dominated galactic halos, in order to
constrain the fraction of halo mass that may be locked-up in white dwarf
stellar remnants. We first construct a 10^9 M_sun stellar halo using the
canonical Salpeter initial stellar mass distribution, and then allow for an
additional component of low- and intermediate-mass stars, which ultimately give
rise to white dwarf remnants. Microlensing observations towards the Large
Magellanic Cloud, coupled with several ground-based proper motion surveys, have
led to claims that in excess of 20% of the dynamical mass of the halo (10^12
M_sun) might be found in white dwarfs. Our results indicate that (1) even if
only 1% of the dynamical mass of the dark halo today could be attributed to
white dwarfs, their main sequence progenitors at high redshift (z ~ 3) would
have resulted in halos more than 100 times more luminous than those expected
from conventional initial mass functions alone, and (2) any putative halo white
dwarf progenitor dominated initial mass function component, regardless of its
dynamical importance, would be virtually impossible to detect at the
present-day, due to its extremely faint surface brightness.


title: Evidence for large superhumps in TX Col and V4742 Sgr

abstract:
  Since the discovery of the largest positive superhump period in TV Col, we
have started a program to search for superhumps in CVs with large orbital
periods. Here, we summarize preliminary results of TX Col and V4742 Sgr. TX Col
is an intermediate polar with a 5.7-h orbital period. V4742 Sgr is a recent
nova with no known periods. CCD unfiltered continuous photometry of these 2
objects was carried out during 56 nights in 2002-3. In TX Col, in addition to
the orbital period of 5.7 h, we found peaks at 7.1 h and 5.0 h. These are
interpreted as positive and negative superhumps correspondingly, although the
effects of the quasi-periodic oscillations at about 2 h were not taken into
consideration. In the light curve of V4742 Sgr 2 long periods are detected --
6.1 and 5.4 h as well as a short-term period at 1.6 h. This result suggests
that V4742 Sgr is an intermediate polar candidate and a permanent superhump
system with a large orbital period (5.4 h) and a superhump period excess of 13
percent. If these results are confirmed, TX Col, V4742 Sgr and TV Col form a
group of intermediate polars with extremely large superhump periods. There
seems to be now growing evidence that superhumps can occur in intermediate
polars with long orbital periods, which is very likely inconsistent with the
theoretical prediction that superhumps can only occur in systems with mass
ratios below 0.33. Alternatively, if the mass ratio in these systems is
nevertheless below the theoretical limit, they should harbour undermassive
secondaries and massive white dwarfs, near the Chandrasekhar limit, which would
make them excellent candidates for progenitors of supernovae type Ia.


title:
Measurements of the Singly Ionized Oxygen Auroral Doublet Lines
  $\lambda\lambda$7320,7330\AA Using High Resolution Sky Spectra

abstract:
  The wavelengths of the individual [O II] 2s22p3 2Do(5/2) - 2s22p3
2Po(1/2,3/2) 7320\AA and [O II] 2s22p3 2Do(3/2) - 2s22p3 2Po(1/2,3/2) 7330\AA
auroral doublet component lines have been measured directly in the nightglow
for the first time, from high resolution spectra obtained with the HIRES
spectrograph on the Keck I telescope at the W.M. Keck Observatory.
Specifically, we find 7320\AA and 7330\AA doublet splittings of
1.077$\pm$0.003\AA and 1.080$\pm$0.003\AA respectively, with the former
significantly larger than the often quoted and utilized value of 0.8\AA from
Moore (1949, Atomic Energy Levels, Vol 1), and in line with NIST (1.07\AA) as
well as more recent astrophysical observations of the lines in planetary
nebulae including 1.07\AA from DeRobertis, Osterbrock, & McKee
(1985,ApJ,293,459) and 1.09\AA from Barnett & McKeith (1988,MNRAS,234,241). Our
results suggest, however, that adjustments of +0.124\AA and +0.131\AA should be
made to current NIST wavelengths for the blue and red components of the 7320\AA
doublet respectively, while the wavelengths of the 7330\AA doublet components
are little changed from current NIST values. The observed intensity ratio of
7320\AA/7330\AA from these measurements agrees with the theoretical value
calculated under conditions of thermally populated 2Po levels.


title: Spectral Evolution of Two High-Energy Gamma-Ray Bursts

abstract:
  The prompt emission of the gamma-ray bursts is found to be very energetic,
releasing ~10^51 ergs in a flash. However, their emission mechanism remains
unclear and understanding their spectra is a key to determining the emission
mechanism. Many GRB spectra have been analyzed in the sub-MeV energy band, and
are usually well described with a smoothly broken power-law model. We present a
spectral analysis of two bright bursts (GRB910503 and GRB930506), using BATSE
and EGRET spectra that cover more than four decades of energy (30 keV - 200
MeV). Our results show time evolutions of spectral parameters (low-energy &
high-energy photon indices and break energy) that are difficult to reconcile
with a simple shock-acceleration model.


title: A Molecular Face-on View of the Galactic Centre Region

abstract:
  We present a method to derive positions of molecular clouds along the lines
of sight from a quantitative comparison between 2.6 mm CO emission lines and 18
cm OH absorption lines, and apply it to the central kiloparsecs of the Milky
Way. With some simple but justifiable assumptions, we derive a face-on
distribution of the CO brightness and corresponding radial velocity in the
Galactic centre without any help of kinematical models. The derived face-on
distribution of the gas is elongated and inclined so that the Galactic-eastern
(positive longitude) side is closer to us. The gas distribution is dominated by
a barlike central condensation, whose apparent size is 500x200 pc. A ridge
feature is seen to stretch from one end of the central condensation, though its
elongated morphology might be artificial. The velocity field shows clear signs
of noncircular motion in the central condensation. The `expanding molecular
ring' feature corresponds to the peripheral region surrounding the central
condensation with the Galactic-eastern end being closer to us. These
characteristics agree with a picture in which the kinematics of the gas in the
central kiloparsec of the Galaxy is under a strong influence of a barred
potential. The face-on distribution of the in situ pressure of the molecular
gas is derived from the CO multiline analysis. The derived pressure is found to
be highest in the central 100 pc. In this region, the gas is accumulating and
is forming stars.


title:
The Effects of Periodically Gapped Time Series on Cross-correlation Lag
  Determinations

abstract:
  The three bright TeV blazars Mrk 421, Mrk 501 and PKS 2155-404 are highly
variable in synchrotron X-ray emission. In particular, these sources may
exhibit variable time lags between flux variations at different X-ray energy
bands. However, there are a number of issues that may significantly bias lag
determinations. Edelson et al. (2001) recently proposed that the lags on
timescales of hours, discovered by ASCA and BeppoSAX, could be an artifact of
periodic gaps in the light curves introduced by the Earth occultation every
\~1.6 hr. Using Monte Carlo simulations, in this paper we show that the lags
over timescales of hours can not be the spurious result of periodic gaps, while
periodic gaps indeed introduces uncertainty larger than what present in the
evenly sampled data. The results also show that time lag estimates can be
substantially improved by using evenly sampled light curves with large lag to
bin-size ratio. Furthermore, we consider an XMM-Newton observation without
interruptions and re-sample the light curves using the BeppoSAX observing
windows, and then repeat the same cross correlation function (CCF) analysis on
both the real and fake data. The results also show that periodic gaps in the
light curves do not significantly distort the CCF characters, and indeed the
CCF peak ranges of the real and fake data overlap. Therefore, the lags
discovered by ASCA and BeppoSAX are not due to periodic gaps in the light
curves.


title:
Electrostatic Instability in Electron-Positron Pairs Injected in an
  External Electric Field

abstract:
  Motivated by the particle acceleration problem in pulsars, we numerically
investigate electrostatic instability of electron-positron pairs injected in an
external electric field. The electric field is expected to be so strong that we
cannot neglect effects of spatial variation in the 0-th order distribution
functions on the scale of the plasma oscillation. We assume that pairs are
injected mono-energetically with 4-velocity $u_0>0$ in a constant external
electric field by which electrons (positrons) are accelerated (decelerated). By
solving linear perturbations of the field and distribution functions of pairs,
we find a new type of electrostatic instability. The properties of the
instability are characterized by $u_0$ and the ratio $R$ of the braking
time-scale (determined by the external electric field) to the time-scale of the
plasma oscillation. The growth rate is as large as a few times the plasma
frequency. We discuss the possibility that the excited waves prevent positrons
from returning to the stellar surface.


title:
The European Large Area ISO Survey IX: the 90 micron luminosity function
  from the Final Analysis sample

abstract:
  We present the 90 micron luminosity function of the Final Analysis of the
European Large Area ISO Survey (ELAIS), extending the sample size of our
previous analysis (paper IV) by about a factor of 4. Our sample extends to
z=1.1, around 50 times the comoving volume of paper IV, and 10^{7.7} <
h^{-2}L/Lsun < 10^{12.5}. From our optical spectroscopy campaigns of the
northern ELAIS 90 mircon survey (7.4 deg^2 in total, to S(90um)>70mJy), we
obtained redshifts for 61% of the sample (151 redshifts) to B<21 identified at
7 microns, 15 microns, 20cm or with bright (B<18.5) optical identifications.
The selection function is well-defined, permitting the construction of the 90
micron luminosity function of the Final Analysis catalogue in the ELAIS
northern fields, which is in excellent agreement with our Preliminary Analysis
luminosity function in the ELAIS S1 field from paper IV. The luminosity
function is also in good agreement with the IRAS-based prediction of Serjeant &
Harrison (2004), which if correct requires luminosity evolution of (1+z)^{3.4
+/- 1.0} for consistency with the source counts. This implies an evolution in
comoving volume averaged star formation rate at z<~1 consistent with that
derived from rest-frame optical and ultraviolet surveys.


title:
An ultra-relativistic outflow from a neutron star accreting gas from a
  companion

abstract:
  Collimated relativistic outflows, or jets, are amongst the most energetic and
relativistic phenomena in the Universe. They are associated with supermassive
black holes in distant active galactic nuclei (AGN), accreting black holes and
neutron stars in binary systems and are believed to be responsible for
gamma-ray bursts. The physics of these jets,however, remains something of a
mystery in that their bulk velocities, compositions and energetics remain
poorly determined. Here we report the discovery of an ultra-relativistic
outflow from a binary accreting neutron star accreting gas within a binary
system. The velocity of the outflow is comparable to the fastest-moving flows
observed from active galactic nuclei, and its strength is modulated by the rate
of accretion of material onto the neutron star. Shocks are energized further
downstream in the flow, which are themselves moving with mildly relativistic
bulk velocities and are the sites of the observed synchrotron emission from the
jet. We conclude that the generation of such highly relativistic outflows does
not require properties unique to black holes, such as an event horizon.


title: INTEGRAL Spectrometer Analysis of GRB030227 & GRB030131

abstract:
  The spectrometer SPI on board INTEGRAL is capable of high-resolution
spectroscopic studies in the energy range 20keV to 8MeV for GRBs which occur
within the fully coded field of view (16 degrees corner to corner). Six GRBs
occurred within the SPI field of view between October 2002 and November 2003.
We present results of the analysis of the first two GRBs detected by SPI after
the payload performance and verification phase of INTEGRAL.


title: Dramatic Spectral Evolution of WZ Sagittae during the 2001 Superoutburst

abstract:
  We carried out optical spectroscopic observations of the most enigmatic dwarf
nova WZ Sge in 11 nights during the 2001 superoutburst. Our observations
covered the period from the initial phase, several hours before the maximum, to
the ninth maximum of the rebrightening phase. The first spectrum shows
absorption lines of H I (except for Halpha), He I, and Na I, as well as
emission lines of He\II, C III/N III, and Halpha in doubly-peaked shapes. The
same spectrum shows the emission lines of C IV and N IV which are the first
detection in dwarf novae. The spectral features dramatically changed in various
time scales. For example, the peak separations of the emission lines of H I and
He II changed from ~700 km/s to 1300 km/s, and one of the peaks dominated over
an orbital period in the genuine-superhump era, but the dominant peak
interchanged with the orbital phase in the early-superhump era. The lines of H
I and He I were in emission at minima of the rebrightening phase (with no
high-excitation lines, nor Na I), while they became in absorption at maxima. We
report on these observational results in detail and their implications
concerning the outburst mechanism, two types of superhumps, and variation of
the disk structure.


title: Phantom cosmology as a simple model with dynamical complexity

abstract:
  We study the Friedmann-Robertson-Walker model with phantom fields modelled in
terms of scalar fields. We apply the Ziglin theory of integrability and find
that the flat model is nonintegrable. Then we cannot expect to determine simple
analytical solutions of the Einstein equations. We demonstrate that there is
only a discrete set of parameters where this model is integrable. For
comparison we describe the phantoms fields in terms of the barotropic equation
of state. It is shown that in the contrast to the phantoms modelled as scalar
fields, the dynamics is always integrable and phase portraits are constructed.
In this case we find the duality relation.


title:
Cosmological Growth History of Supermassive Black Holes and Demographics
  in the High-z Universe : Do Lyman-Break Galaxies Have Supermassive Black
  Holes?

abstract:
  We study the demographics of supermassive black holes (SMBHs) in the local
and high-z universe with hard X-ray luminosity functions (HXLFs) of AGNs.
First, we compare the mass accretion history at z>0 with optical luminosity
functions (OLFs) and that with HXLFs. We consider the constraints on parameters
of mass accretion (energy conversion efficiency and Eddington ratio) and
conclude that the constraints based on HXLFs are more adequate rather than that
based on OLFs. The sub-Eddington case is allowed only when we use HXLFs. Next,
we estimate the upper limit of the cumulative mass density of SMBHs at any
redshifts. For an application, we examine if Lyman-Break galaxies (LBGs) at z=3
already have SMBHs in their centers which is suggested by recent observations.
If most of LBGs already has massive SMBHs at z=3, the resultant mass density of
SMBHs at z=0 should exceed the observational estimate because such SMBHs should
further grow by accretion. We show that the special conditions should be met in
order that a large part of LBGs have SMBHs (for example, large energy
conversion efficiency and frequent mergers and/or direct formations at z>3).
The possibility that nearly all LBGs have SMBHs with large mass ratio, such as
M_BH/M_stellar > 0.005, is reliably ruled out.(abridged)


title: Gravitational Faraday rotation in a weak gravitational field

abstract:
  We examine the rotation of the plane of polarization for linearly polarized
light rays by the weak gravitational field of an isolated physical system.
Based on the rotation of inertial frames, we review the general integral
expression for the net rotation. We apply this formula, analogue to the usual
electromagnetic Faraday effect, to some interesting astrophysical systems:
uniformly shifting mass monopoles and a spinning external shell.


title: WMAP Constraints on a Quintessence Model

abstract:
  We use the results from the Wilkinson Microwave Anisotropy Probe (WMAP) for
the locations of peaks and troughs of the Cosmic Microwave Background (CMB)
power spectrum, together with constraints from large-scale structure, to study
a quintessence model in which the pure exponential potential is modified by a
polynomial factor. Our analysis, in the $(\Omega_m, h, n_s)$ cosmological
parameters space shows that this quintessence model is favoured compared to
$\Lambda$CDM for $n_s\approx 1$ and relatively high values of early
quintessence; for $n_s<1$, quintessence and $\Lambda$CDM give similar results,
except for high values of early quintessence, in which case $\Lambda$CDM is
favoured.


title:
Abundance Constraints and Direct Redshift Measurement of the Diffuse
  X-ray Emission from a Distant Cluster of Galaxies

abstract:
  We report on the XMM-Newton (XMM) observation of RXJ1053.7+5735, one of the
most distant X-ray selected clusters of galaxies, which also shows an unusual
double-lobed X-ray morphology, indicative of a possible equal-mass cluster
merger. The cluster was discovered during the ROSAT deep pointings in the
direction of the Lockman Hole. All XMM Lockman Hole observations (PV, AO-1 &
AO-2 phases) with the European Photon Imaging Camera (EPIC) were combined for
the analysis, totaling exposure times ~ 648 ks, 738 ks, and 758 ks for pn,
MOS1, and MOS2, respectively. With this 'deep' dataset, we could detect the Fe
K line and obtain a strong constraint on cluster metallicity, which is
difficult to achieve for clusters at z > 1. The best-fit abundance is 0.46
+0.11/-0.07 times the solar value. The Fe line emission also allows us to
directly estimate the redshift of diffuse gas, with a value z = 1.14
+0.01/-0.01. This is one of the first clusters whose X-ray redshift is directly
measured prior to the secure knowledge of cluster redshift by optical/NIR
spectroscopy. We could also estimate the X-ray redshift separately for each of
the two lobes in the double-lobed structure, and the result is consistent with
the two lobes being part of one cluster system at the same redshift. Comparison
with other metallicity measurements of nearby and distant clusters shows that
there is little evolution in the ICM metallicity from z ~ 1 to the present.


title:
The HELLAS2XMM survey. V. Near-Infrared observations of X-ray sources
  with extreme X/O ratios

abstract:
  We present the results of deep near-infrared observations of 11 hard X-ray
selected sources in the Hellas2XMM survey, with faint optical magnitude (R>24)
and high X-ray-to-optical flux ratio. All but one of the sources have been
detected in the Ks band, with bright counterparts (Ks<19) and red colors
(R-K>5), and therefore belong to the ERO population. A detailed analysis of the
surface brightness profiles allows us to classify all of the NIR counterparts.
There are 2 point-like objects, 7 elliptical galaxies and one source with a
disky profile. None of the extended sources shows any evidence for the presence
of a central unresolved object tracing the putative X-ray emitting AGN. Using
both the R-K colors and the morphological information, we have estimated for
all the sources a ``minimum photometric redshift'', ranging between 0.8 and
2.4; the elliptical hosts have zmin=0.9-1.4. We computed the X-ray properties
using these redshifts: most of the sources have NH>10^{22}, with unabsorbed
X-ray luminosities up to 10^{45}erg s^{-1}. These objects therefore belong to
the population of obscured (Type II) quasars and, from a statistical point of
view, they turn out to be a non-negligible fraction (~10%) of the most luminous
AGN. Selecting the high X/O sources for a follow-up study in the NIR is
therefore a powerful technique aimed at studying at high redshift the hosts of
Type II AGN. Overall, our results seem to indicate that the hosts are mostly
elliptical galaxies at z~1, and that these near-IR bright objects would be
among the most massive spheroids at these epochs.


title: A possible new dipping X-ray source in the field of M31

abstract:
  We report the discovery of the new dipping X-ray source, XMMU
J004308.6+411247, in M31, during a systematic search for periodicities in
XMM-Newton archival observations. During the 2002 January 6 observation, the
dips recur with a 107 min period and the source count rate is consistent with
zero at the dip minimum. Dips with the same modulation and period are also
observed during the XMM-Newton observations carried out on 2000 June 25, 2001
June 29 and the Chandra observation of 2001 October 5. The dips of XMMU
J004308.6+411247 show no evidence of energy dependence. The average X-ray flux
of XMMU J004308.6+411247 is nearly constant across different observations
(~1.e37 erg/s for an assumed M31 distance of 780 kpc in the 0.3-10 keV band);
the spectrum is well fit by an absorbed power law with a photon index ~0.8 or
an absorbed Comptonization model. The photo-electric absorption is consistent
with the Galactic value in the source direction. If XMMU J004308.6+411247 is
located in M31 its properties are consistent with those of dipping low mass
X-ray binaries in the Galaxy. Present observations do not allow to distinguish
between dips and eclipses. The possibility that XMMU J004308.6+411247 is a
foreground X-ray source cannot be ruled out at present; in this case the source
might be a magnetic cataclysmic variable.


title: On the detectability of lightcurves of Kuiper Belt objects

abstract:
  We present a statistical study of the detectability of lightcurves of Kuiper
Belt objects (KBOs). Some Kuiper Belt objects display lightcurves that appear
"flat", i.e., there are no significant brightness variations within the
photometric uncertainties. Under the assumption that KBO lightcurves are mainly
due to shape, the lack of brightness variations may be due to (1) the objects
have very nearly spherical shapes, or (2) their rotation axes coincide with the
line of sight. We investigate the relative importance of these two effects and
relate it to the observed fraction of "flat" lightcurves. This study suggests
that the fraction of KBOs with detectable brightness variations may provide
clues about the shape distribution of these objects. Although the current
database of rotational properties of KBOs is still insufficient to draw any
statistically meaningful conclusions, we expect that, with a larger dataset,
this method will provide a useful test for candidate KBO shape distributions.


title:
Observations of 54 Active Galactic Nuclei with the HEGRA System of
  Cherenkov Telescopes

abstract:
  A sample of 54 selected Active Galactic Nuclei (AGN) has been observed with
the HEGRA stereoscopic system of Cherenkov Telescopes between 1996 and 2002 in
the TeV energy regime. The observations were motivated by the positive results
obtained for Mkn 421 and Mkn 501. The distances of the selected objects vary
over a large range of redshifts between z = 0.004 and z = 0.7. Among the
observed AGN are the meanwhile established TeV-emitting BL Lac type objects
H1426+428 and 1ES1959+650. Furthermore the BL Lac object 1ES2344+514 and the
radio galaxy M87 show evidence for a signal on a 4 sigma level. The observation
of 1ES2344+514 together with the Whipple results firmly establishes this AGN as
a TeV source. Several objects (PKS2155-304, BL Lacertae, 3C066A) that have been
claimed as TeV gamma-ray emitters by other groups are included in this data
sample but could not be confirmed using data analysed here. The upper limits of
several AGN included in this analysis are compared with predictions in the
frame-work of SSC models.


title: On the Amount of Gravitational Waves from Inflation

abstract:
  The curvaton and the inhomogeneous reheating scenarios for the generation of
the cosmological curvature perturbation on large scales represent an
alternative to the standard slow-roll scenario where the observed density
perturbations are due to fluctuations of the inflaton field itself. The basic
assumption of the curvaton and inhomogeneous reheating mechanisms is that the
initial curvature perturbation due to the inflaton field is negligible. This is
usually attained by lowering the energy scale of inflation thereby concluding
that the amount of gravitational waves produced during inflation is highly
suppressed. We show, contrary to this common lore, that the curvaton and the
inhomogeneous reheating scenarios are compatible with a level of gravity-wave
fluctuations which may well be observed in future satellite experiments. This
conclusion does not involve, as in the slow-roll inflationary models,
embarrasingly large field variations in units of the Planck scale. As a working
example, we illustrate the recently proposed stringy version of old inflation.


title: Far-infrared loops in the 2nd Galactic Quadrant

abstract:
  We present the results of an investigation of the large scale structure of
the diffuse interstellar medium in the 2nd Galactic Quadrant (90 <= l <= 180).
145 loops were identified on IRAS based far-infrared maps. Our catalogue lists
their basic physical properties. The distribution clearly suggests that there
is an efficient process that can generate loop-like features at high galactic
latitudes. Distances are provided for 30 loops. We also give an observational
estimate on the volume filling factor of the hot gas in the Local Arm, 4.6% <=
f_2nd <= 6.4%


title: Simulating the recent star formation history in the halo of NGC 5128

abstract:
  Simulated color-magnitude diagrams (CMDs) are used to investigate the recent
star formation history in NGC 5128. The comparison of the simulations with the
observed UV CMD for a field in the NE shell, where recent star formation is
present, constrains the initial mass function (IMF) and the duration of the
star formation episode. The star formation burst is still on-going or at most
has stopped some 2 Myr ago. The look-back time on the main sequence is set by
the incompleteness of the U-band observations at V~26, and is of the order of
50 Myr. The post main sequence phases have a look-back time up to 100 Myr,
setting the maximum observable time for the star formation in this field. The
comparison of the observed and simulated luminosity functions and the number of
post main sequence vs. total number of stars favours models with active star
formation in the last 100 Myr. The data are best fitted by an IMF with Salpeter
slope (\alpha=2.35), and are also consistent with slopes in the range of
2<~\alpha<~2.6. They exclude steeper IMF slopes. The mean star formation rate
for a Salpeter IMF in the range of masses 0.6<~M<~100 M_sun within the last 100
Myr is 1.6x10^-4 M_sun yr^-1 kpc^-2.


title: On the deep minimum state in the Seyfert galaxy MCG-6-30-15

abstract:
  (abridged) We present a detailed spectral analysis of the first observation
of the Seyfert 1 galaxy MCG-6-30-15 by the European Photon Imaging Camera on
board the XMM-Newton observatory, together with contemporaneous data from the
Proportional Counter Array on the Rossi X-ray Timing Explorer. Confirming our
previously published result, we find that the presence of extremely broadened
reflection features from an ionized relativistic accretion disk is required
even when one employs the latest X-ray reflection models and includes the
effect of complex absorption. The extremely broadened reflection features are
also present if the primary continuum is modeled with a thermal Comptonisation
spectrum rather than a simple power-law continuum. With this fact established,
we examine these data using a relativistic smearing function corresponding to a
``generalized thin accretion disk'' model. We find strong evidence for torquing
of the central parts of the accretion disk (presumably through magnetic
interactions with the plunging region of the disk and/or the rotating black
hole itself). We also perform a study of spectral variability within our
observation. We find that the disk reflection features maintain roughly a
constant equivalent width with respect to the observed continuum, as predicted
by simple reflection models. Taken together with other studies of MCG-6-30-15
that find disk features to possess constant intensity at higher flux states, we
suggest that the flux of disk features undergoes a saturation once the source
emerges from a Deep Minimum state.


title:
Chandra observations of five ultraluminous X-ray sources in nearby
  galaxies

abstract:
  We report the results of a programme of dual-epoch Chandra ACIS-S
observations of five ultraluminous X-ray sources (ULXs) in nearby spiral
galaxies. All five ULXs are detected as unresolved, point-like X-ray sources by
Chandra, though two have faded below the 10^39 erg/s luminosity threshold used
to first designate these sources as ULXs. Using this same criterion, we detect
three further ULXs within the imaged regions of the galaxies. The ULXs appear
to be related to the star forming regions of the galaxies, indicating that even
in ``normal'' spiral galaxies the ULX population is predominantly associated
with young stellar populations. A detailed study of the Chandra ACIS-S spectra
of six of the ULXs shows that five are better described by a powerlaw continuum
than a multi-colour disc blackbody model, though there is evidence for
additional very soft components to two of the powerlaw continua. The measured
photon indices in four out of five cases are consistent with the low/hard state
in black hole binaries, contrary to the suggestion that powerlaw-dominated
spectra of ULXs originate in the very high state. A simple interpretation of
this is that we are observing accretion onto intermediate-mass black holes,
though we might also be observing a spectral state unique to very high mass
accretion rates in stellar-mass black hole systems. Short-term flux variability
is only detected in one of two epochs for two of the ULXs, with the lack of
this characteristic arguing that the X-ray emission of this sample of ULXs is
not dominated by relativistically-beamed jets. The observational
characteristics of this small sample suggest that ULXs are a distinctly
heterogeneous source class.


title:
Search for non-Gaussianity in pixel, harmonic and wavelet space:
  compared and combined

abstract:
  We present a comparison between three approaches to test non-Gaussianity of
cosmic microwave background data. The Minkowski functionals, the empirical
process method and the skewness of wavelet coefficients are applied to maps
generated from non-standard inflationary models and to Gaussian maps with point
sources included. We discuss the different power of the pixel, harmonic and
wavelet space methods on these simulated almost full-sky data (with Planck like
noise). We also suggest a new procedure consisting of a combination of
statistics in pixel, harmonic and wavelet space.


title: INTEGRAL observations of the transient source IGR J19140+098

abstract:
  IGR J19140+098 was discovered during the early INTEGRAL observations of
GRS1915+105 in March 2003. The following observations by INTEGRAL and RXTE show
significant variability on various time scales from 100s to 1ks, but no
pulsations. The ISGRI spectra show strong spectral variability in the 20-80keV
range. Combined JEMX_2-ISGRI spectra are well fitted by a power-law and a
thermal emission model with a rather high temperature. RXTE data also reveal an
apparently broad ionised iron line not detected in earlier INTEGRAL
observations. These results are compatible with a galactic X-ray binary source.


title: Carbon budget and carbon chemistry in Photon Dominated Regions

abstract:
  We present a study of small carbon chains and rings in Photon Dominated
Regions (PDRs) performed at millimetre wavelengths. Our sample consists of the
Horsehead nebula (B33), the rho,Oph L1688 cloud interface, and the
cometary-shaped cloud IC63. Using the IRAM 30-m telescope, the SEST and the
Effelsberg 100-m teles cope at Effelsberg., we mapped the emission of \cch,
c-C3H2 and C4H, and searched for heavy hydrocarbons such as c-C3H, l-C3H,
l-C3H2, l-C4H2 and C6H. The large scale maps show that small hydrocarbons are
present until the edge of all PDRs, which is surprising as they are expected to
be easily destroyed by UV radiation. Their spatial distribution reasonably
agrees with the aromatic emission mapped in mid-IR wavelength bands. Their
abundances relative to H2 are relatively high and comparable to the ones
derived in dark clouds such as L134N or TMC-1, known as efficient carbon
factories. In particular, we report the first detection of C6H in a PDR. We
have run steady-state PDR models using several gas-phase chemical networks
(UMIST95 and the New Standard Model) and conclude that both networks fail in
reproducing the high abundances of some of these hydrocarbons by an order of
magnitude. The high abundance of hydrocarbons in the PDR may suggest that the
photo-erosion of UV-irradiated large carbonaceous compounds could efficiently
feed the ISM with small carbon clusters or molecules. This new production
mechanism of carbon chains and rings could overcome their destruction by the UV
radiation field. Dedicated theoretical and laboratory measurements are required
in order to understand and implement these additional chemical routes.


title:
High-energy neutrinos as observational signature of massive black hole
  formation

abstract:
  We describe the formation of a seed massive black hole (MBH) inside a
supermassive star (SMS) in a distant galactic nucleus. The short-lived SMS is
naturally formed due to collision destructions of normal stars in the evolving
galactic nucleus. The neutron stars (NSs) and stellar-mass black holes form a
compact self-gravitating subsystem deep inside a SMS. This subsystem is
short-lived in comparison with a host SMS and collapses finally into the MBH.
Just before gravitational collapse of compact subsystem the frequent NS
collisions are accompanied by the generation of numerous ultra-relativistic
fireballs. A combined ram pressure of multiple coexisting fireballs produces a
quasi-stationary rarefied cavity in the central part of SMS. The protons are
accelerated in the fireballs and by relativistic shocks in the cavity. All
secondary particles, produced in collisions, except the high-energy neutrinos
are absorbed in the SMS interiors. An estimated high-energy neutrino signal
from this hidden source can be detected by the neutrino telescope with an
effective area 1 km^2 providing the evidence for MBH formation in a distant
galactic nucleus. A corresponding lifetime of this high-energy hidden neutrino
source is ~0.1-1 yr.


title:
HETE Observations of the Gamma-Ray Burst GRB030329: Evidence for an
  Underlying Soft X-ray Component

abstract:
  An exceptionally intense gamma-ray burst, GRB030329, was detected and
localized by the instruments on board the High Energy Transient Explorer
satellite (HETE) at 11:37:14 UT on 29 March 2003. The burst consisted of two
\~10s pulses of roughly equal brightness and an X-ray tail lasting >100s. The
energy fluence in the 30-400 keV energy band was 1.08e-4 erg/cm2, making
GRB030329 one of the brightest GRBs ever detected. Communication of a 2 arcmin
error box 73 minutes after the burst allowed the rapid detection of a
counterpart in the optical, X-ray, radio and the ensuing discovery of a
supernova with most unusual characteristics. Analyses of the burst lightcurves
reveal the presence of a distinct, bright, soft X-ray component underlying the
main GRB: the 2-10 keV fluence of this component is ~7e-6 erg/cm2. The main
pulses of GRB030329 were preceded by two soft, faint, non-thermal bumps. We
present details of the HETE observations of GRB030329.


title: Spectral Analysis of RXTE Observations of A3667

abstract:
  X-ray emission from the cluster of galaxies A3667 was measured by the PCA and
HEXTE experiments aboard the RXTE satellite during the period December 2001 -
July 2002. Analysis of the ~141 ks RXTE observation and lower energy ASCA/GIS
data, yields only marginalevidence for a secondary power-law emission component
in the spectrum. The 90% confidence upper limit on nonthermal emission in the
15-35 keV band is determined to be 2.6x10^{-12} erg/(cm^{2}s). When combined
with the measured radio flux and spectral index of the dominant region of
extended radio emission, this upper limit implies a lower limit of ~0.4
microgauss on the mean, volume-averaged intracluster magnetic field in A3667.


title: Can Non-Adiabatic Perturbations Arise After Single-Field Inflation?

abstract:
  It is shown that non-adiabatic cosmological perturbations cannot arise during
the period of reheating following inflation with a single scalar inflaton
field.


title: The Changing Blazhko Effect of XZ Cygni

abstract:
  New CCD photometry has been obtained for the RR Lyrae variable star XZ Cygni.
An analysis of old and new photometry confirms earlier results that XZ Cygni
exhibits the Blazhko Effect and that its Blazhko period has changed over time.
These changes in the Blazhko period are anticorrelated with observed changes in
the primary period of XZ Cygni. During the first half of the twentieth century,
XZ Cygni had a Blazhko period of approximately 57.4 d. Beginning in 1965, its
primary period underwent a steep decline in several steps. Coincidentally, its
Blazhko period increased to about 58.5 d. In 1979, the primary period suddenly
increased again. After an interval in which the Blazhko Effect was small, the
Blazhko Effect re-established itself, with a period of approximately 57.5 d.
When its Blazhko period is near 57.5 d, XZ Cygni has also shown a tertiary
period of 41.6 d. We confirm that there is evidence for a longer 3540 d period
in photometry obtained during the first half of the twentieth century. XZ Cygni
is compared with three other RR Lyrae stars which also appear to show changing
Blazhko periods. The observed changes in the length of the Blazhko period of XZ
Cygni constrain possible explanations for the Blazhko Effect. In particular,
they argue against any theoretical explanation which requires that the Blazhko
period be exactly equal to or directly proportional to the rotation period of
the star.


title: On the jet structure and magnetic field configuration of GRB 020813

abstract:
  The polarization curve of GRB 020813 is discussed and compared to different
models for the structure, evolution and magnetisation properties of the jet and
the interstellar medium onto which the fireball impacts. GRB 020813 is best
suited for this kind of analysis for the smoothness of its afterglow light
curve, ensuring the applicability of current models. The polarization dataset
allows us to rule out the standard GRB jet, in which the energy and Lorentz
factor have a well defined value inside the jet opening angle and the magnetic
field is generated at the shock front. We explore alternative models finding
that a structured jet or a jet with a toroidal component of the magnetic field
can fit equally well the polarization curve. Stronger conclusions cannot be
drawn due to the incomplete sampling of the polarization curve. A more dense
sampling, especially at early times, is required to pin down the structure of
the jet and the geometry of its magnetic field.


title:
Spectroscopy of Seven Cataclysmic Variables with Periods Above Five
  Hours

abstract:
  We present spectroscopy of seven cataclysmic variable stars with orbital
periods P(orb) greater than 5 hours, all but one of which are known to be dwarf
novae. Using radial velocity measurements we improve on previous orbital period
determinations, or derive periods for the first time. The stars and their
periods are
  TT Crt, 0.2683522(5) d;
  EZ Del, 0.2234(5) d;
  LL Lyr, 0.249069(4) d;
  UY Pup, 0.479269(7) d;
  RY Ser, 0.3009(4) d;
  CH UMa, 0.3431843(6) d; and
  SDSS J081321+452809, 0.2890(4) d.
  For each of the systems we detect the spectrum of the secondary star,
estimate its spectral type, and derive a distance based on the surface
brightness and Roche lobe constraints. In five systems we also measure the
radial velocity curve of the secondary star, estimate orbital inclinations, and
where possible estimate distances based on the MV(max) vs.P(orb) relation found
by Warner. In concordance with previous studies, we find that all the secondary
stars have, to varying degrees, cooler spectral types than would be expected if
they were on the main sequence at the measured orbital period.


title:
The Thermal Evolution following a Superburst on an Accreting Neutron
  Star

abstract:
  Superbursts are very energetic Type I X-ray bursts discovered in recent years
by long term monitoring of X-ray bursters, and believed to be due to unstable
ignition of carbon in the deep ocean of the neutron star. In this Letter, we
follow the thermal evolution of the surface layers as they cool following the
burst. The resulting lightcurves agree very well with observations for layer
masses and energy releases in the range expected from ignition calculations. At
late times, the cooling flux from the layer decays as a power law in time,
giving timescales for quenching of normal Type I bursting of weeks, in good
agreement with observational limits. We show that simultaneous modelling of
superburst lightcurves and quenching times promises to constrain both the
thickness of the fuel layer and the energy deposited.


title: A Search for Warm Circumstellar Disks in the TW Hydrae Association

abstract:
  A search for previously undetected optically thin disks around stars in the
nearby, young, TW Hydrae Association was conducted around sixteen stars with
sensitive 12 and 18 micron photometry. The survey could detect Zodiacal-like
dust, with temperature 200-300 K, at levels of L(IR)/L(*)=7e-3. Possible
mid-infrared excess emission from TWA 17 was detected at the 2-sigma level, but
none of the other stars showed evidence for circumstellar dust. The rapid
disappearance of large amounts of dust around the K and M-type stars in this
sample may mean that any planet formation in the terrestrial planet region was
completed very quickly. There appears to be a bi-modal distribution of dust
disks in TWA with stars having either copious or negligible warm dust.


title:
High Levels of Circularly Polarized Emission from the Radio Jet in NGC
  1275 (3C 84)

abstract:
  We present multi-frequency, high resolution VLBA circular polarization images
of the radio source 3C 84 in the center of NGC 1275. Our images reveal a
complex distribution of circular polarization in the inner parsec of the radio
jet, with local levels exceeding 3% polarization, the highest yet detected with
VLBI techniques. The circular polarization changes sign along the jet, making
3C 84 also the first radio jet to show both signs of circular polarization
simultaneously. The spectrum and changing sign of the circular polarization
indicate that it is unlikely to be purely intrinsic to the emitted synchrotron
radiation. The Faraday conversion process makes a significant and perhaps
dominant contribution to the circular polarization, and the observed spectrum
suggests the conversion process is near saturation. The sign change in the
circular polarization along the jet may result from this saturation or may be
due to a change in magnetic field order after an apparent bend in the jet. From
the small spatial scales probed here, ~ 0.15 pc, and the comparably high levels
of circular polarization inferred for the intra-day variable source PKS
1519-273, we suggest a connection between small spatial scales and efficient
production of circular polarization.


title: Polarization of AGN Jets

abstract:
  The sensitivity, stability, and uniformity of calibration of the VLBA has
revolutionized parsec-scale polarization studies of AGN jets. Not only does
polarization probe the magnetic field structures of jets, serving as a
hydrodynamic tracer of shocks, bends, and shear, but polarization also probes
the medium through which it propagates by encoding the signature of Faraday
effects along the line of sight. I review advances made by the VLBA in studying
the polarization of jets to probe their magnetic field structures, properties
of the jet plasma, and properties of the external environment. This review
covers both linear and circular polarization and is set in the context of
outstanding questions in the field.


title: The double-layered chemical structure in DB white dwarfs

abstract:
  We study the structure and evolution of white dwarf stars with helium-rich
atmospheres (DB) in a self-consistent way with the predictions of
time-dependent element diffusion. Our treatment of diffusion includes
gravitational settling and chemical and thermal diffusion. OPAL radiative
opacities for arbitrary metallicity and carbon-and oxygen-rich compositions are
employed. Emphasis is placed on the evolution of the diffusion-modeled
double-layered chemical structure. This structure, which is characterized by a
pure helium envelope atop an intermediate remnant shell rich in helium, carbon
and oxygen, is expected for pulsating DB white dwarfs, assuming that they are
descendants of hydrogen-deficient PG1159 post-AGB stars. We find that,
depending on the stellar mass, if DB white dwarf progenitors are formed with a
helium content smaller than \approx 10^-3 M_*, a single-layered configuration
is expected to emerge during the DB pulsation instability strip. We also
explore the consequences of diffusively evolving chemical stratifications on
the adiabatic pulsational properties of our DB white dwarf models. In this
context, we find that the evolving shape of the chemical profile translates
into a distinct behaviour of the theoretical period distribution as compared
with the case in which the shape of the profile is assumed to be fixed during
the evolution across the instability strip. Finally, we extend the scope of the
calculations to the domain of the helium-rich carbon-contaminated DQ white
dwarfs. In particular, we speculate that DQ white dwarfs with low detected
carbon abundances would not be descendants of the PG1159 stars.


title: 3-D Explosions: A Meditation on Rotation (and Magnetic Fields)

abstract:
  This is the text of an introduction to a workshop on asymmetric explosions
held in Austin in June, 2003. The great progress in supernova research over
thirty-odd years is briefly reviewed. The context in which the meeting was
called is then summarized. The theoretical success of the intrinsically
multidimensional delayed detonation paradigm in explaining the nature of Type
Ia supernovae coupled with new techniques of observations in the near IR and
with spectropolarimetry promise great advances in understanding binary
progenitors, the explosion physics, and the ever more accurate application to
cosmology. Spectropolarimetry has also revealed the strongly asymmetric nature
of core collapse and given valuable perspectives on the supernova - gamma-ray
burst connection. The capability of the magneto-rotational instability to
rapidly create strong toroidal magnetic fields in the core collapse ambiance is
outlined. This physics may be the precursor to driving MHD jets that play a
role in asymmetric supernovae. Welcome to the brave new world of
three-dimensional explosions!


title: Conference Summary: Three Dimensional Explosions

abstract:
  This is the text of a summary of the workshop on asymmetric explosions held
in Austin in June, 2003. A brief review is given of the author's own interests
in dynamo theory as it may apply in the core collapse ambience. Of particular
interest are saturation fields for the cases with central neutron stars and
black holes and the possibility of driving MHD jets with the resulting fields.
Interesting physics that may arise with large fields such as effects on the
equation of state to produce anisotropic pressure and effects on neutrino cross
sections and transport are briefly outlined. A brief summary of the
contributions to the workshop is then given with special credit to Scratchy
Serapkin. Of special note were the summaries of the advances due to
spectropolarimetry in revealing the asymmetric nature of supernovae. Major
progress in understanding the binary progenitors and explosion physics of Type
Ia was presented. Other talks entwined the nature of asymmetric core collapse,
gamma-ray bursts and "hypernovae." My final charge to the attendees was "Go
thee forth and think about rotation and magnetic fields!"


title: Direct Analysis of Spectra of the Peculiar Type Ia Supernova 2000cx

abstract:
  The Type Ia SN 2000cx exhibited multiple peculiarities, including a lopsided
B-band light-curve peak that does not conform to current methods for using
shapes of light curves to standardize SN Ia luminosities. We use the
parameterized supernova synthetic-spectrum code SYNOW to study line
identifications in the photospheric-phase spectra of SN 2000cx. Previous work
established the presence of Ca II infrared-triplet features forming above
velocity about 20,000 km/s, much higher than the photospheric velocity of about
10,000 km/s. We find Ti II features forming at the same high velocity.
High-velocity line formation is partly responsible for the photometric
peculiarities of SN 2000cx: for example, B-band flux blocking by Ti II
absorption features that decreases with time causes the B light curve to rise
more rapidly and decline more slowly than it otherwise would.
  SN 2000cx contains an absorption feature near 4530 A that may be H-beta,
forming at the same high velocity. The lack of conspicuous H-alpha and P-alpha
signatures does not necessarily invalidate the H-beta identification if the
high-velocity line formation is confined to a clump that partly covers the
photosphere and the H-alpha and P-alpha source functions are elevated relative
to that of resonance scattering. The H-beta identification is tentative. If it
is correct, the high-velocity matter must have come from a nondegenerate
companion star.


title:
Dynamically Influenced Molecular Clouds in the Nucleus of NGC 6946:
  Variations in the CO Isotopic Line Ratios

abstract:
  We present high resolution (~5'') maps of the J = 1 - 0 transitions of
^{13}CO and C^{18}O towards the nucleus of NGC 6946, made with the Owens Valley
Millimeter Array. The images are compared with existing ^{12}CO(1-0) maps to
investigate localized changes in gas properties across the nucleus. As compared
to ^{12}CO, both ^{13}CO and C^{18}O are more confined to the central ring of
molecular gas associated with the nuclear star formation; that is, ^{12}CO is
stronger relative to ^{13}CO and C^{18}O away from the nucleus and along the
spiral arms. The ^{12}CO(1-0)/^{13}CO(1-0) line ratio reaches very high values
of >40. We attribute the relative ^{13}CO weakness to a rapid change in the
interstellar medium from dense star forming cores in a central ring to diffuse,
low density molecular gas in and behind the molecular arms. This change is
abrupt, occurring in less than a beamsize (90 pc), about the size of a giant
molecular cloud. Column densities determined from ^{13}CO(1-0), C^{18}O(1-0),
and 1.4 mm dust continuum all indicate that the standard Galactic conversion
factor, X_{CO}, overestimates the amount of molecular gas in NGC 6946 by
factors of ~3-5 towards the central ring and potentially even more so in the
diffuse gas away from the central starburst. We suggest that the nuclear bar
acts to create coherent regions of molecular clouds with distinct and different
physical conditions. The ^{12}CO(1-0)/^{13}CO(1-0) line ratio in galactic
nuclei can be a signpost of a dynamically evolving ISM.


title:
High Resolution Millimeter Imaging of the Proto-Planetary Nebula He
  3-1475

abstract:
  We report high resolution (1-2 arcsec) imaging of the CO 2-1 line and the
millimeter continuum in the proto-planetary nebula He 3-1475. The observations
reveal the presence of a massive (~0.6 M_sun} envelope of molecular gas around
the origin of the remarkable bipolar jet system seen in optical images with the
HST. The CO kinematics are well modeled by an expanding, bi-conical envelope:
the prominent, high-velocity (~50 km/s) wings seen in single-dish CO spectra
arise where the sides of the bi-cones are projected along the line of sight.
The continuum is detected at 1.3 mm and 2.6 mm and is due to thermal emission
from warm (~80 K) circumstellar dust. The structure, kinematics, and expansion
time of the envelope provide strong evidence for entrainment of the molecular
gas by the high velocity jets. The observations support an evolutionary
scenario in which a period of enhanced mass loss by the central star is
followed by the development of the bipolar jets which burst through the
molecular envelope. The jet-envelope interactions play a crucial role in
shaping the subsequent ionized nebula.


title: High Resolution X-ray Spectroscopy of G292.0+1.8/MSH 11-54

abstract:
  We present a preliminary analysis of XMM-Newton observations of the
oxygen-rich supernova remnant G292.0+1.8 (MSH 11-54). Although the spatial
extent of the remnant is 8 arcmin the bright central bar is narrow (1'-2')
resulting in RGS spectra of a high spectral quality. This allows us to
spectroscopically identify a cool, Te = 0.3 keV, and underionized component,
resolve details of the Fe-L complex, and resolve the forbidden and resonant
lines of the O VII triplet. We are also able to constrain the kinematics of the
remnant using Ne IX as observed in the second order spectrum, and O VIII in the
first order spectrum. We do not find evidence for O VII line shifts or Doppler
broadening (sigma_v < 731 km/s), but line broadening of the Ne X Ly-alpha line
seems to be present, corresponding to sigma_v ~ 1500 km/s.


title: Reprocessing of Soft X-ray Emission Lines in Black Hole Accretion Disks

abstract:
  By means of a Monte Carlo code that accounts for Compton scattering and
photoabsorption followed by recombination, we have investigated the radiation
transfer of Ly alpha, He alpha, and recombination continua photons of H- and
He-like C, N, O, and Ne produced in the photoionized atmosphere of a
relativistic black hole accretion disk. We find that photoelectric opacity
causes significant attenuation of photons with energies above the O VIII
K-edge; that the conversion efficiencies of these photons into lower-energy
lines and recombination continua are high; and that accounting for this
reprocessing significantly (by factors of 21% to 105%) increases the flux of
the Ly alpha and He alpha emission lines of H- and He-like C and O escaping the
disk atmosphere.


title: Neutrino Star as Galactic Cluster Dark Halo

abstract:
  Recent Strong lensing data and rotation curves of dwarf galaxies indicate
that many galactic clusters may have a soft core instead of a central cusp in
their density distribution. This result challenges the standard CDM (Cold Dark
Matter) theory prediction based on N-body simulations. We find that the
observed density profile is consistent with that of a spherical gas of
degenerate fermions such as neutrinos in hydrostatic equilibrium. Also, we
compare two different models of the dark matter halo and their predictions for
the hot gas profile.


title: UBVRI CCD photometric study of the open clusters Basel 4 and NGC 7067

abstract:
  In this paper we present UBVRI CCD photometry in the region of two young open
star clusters Basel 4 and NGC 7067 for the first time. Our sample consists of ~
4000 stars down to V ~ 21 mag. Stellar surface density profile indicates that
radius of Basel 4 and NGC 7067 are about 1.8 and 3.0 arcmin respectively.The
(U-B) versus (B-V) diagrams indicate that metallicity of NGC 7067 is solar
while that of Basel 4 is Z ~ 0.008. We estimate the mean value of E(B-V) =
0.45$\pm$0.05 and 0.75$\pm$0.05 mag for Basel 4 and NGC 7067 respectively. The
analysis of 2MASS JHK data in combination with the optical data in both the
clusters yields E(J-K) = 0.30$\pm$0.20 mag and E(V-K) = 1.60$\pm$0.20 mag for
Basel 4 while E(J-K) = 0.40$\pm$0.20 mag and E(V-K) = 2.10$\pm$0.20 mag for NGC
7067. Furthermore, colour excess diagrams show a normal interstellar extinction
law towards both the clusters.
  Using the intrinsic colour-magnitude diagrams of the cluster members, we
estimated the distances of the clusters as 3.0$\pm$0.2 and 3.6$\pm$0.2 Kpc for
Basel 4 and NGC 7067 respectively. By fitting the proper metallicity isochrones
to the bright cluster members we estimated the age of the clusters as
200$\pm$50 and 100$\pm$25 Myr for Basel 4 and NGC 7067 respectively. The mass
function slope which is derived by applying the corrections of field star
contamination and data incompleteness are $1.55\pm0.25$ and $1.68\pm0.47$ for
Basel 4 and NGC 7067 respectively. The values of mass function slopes are thus
not too different from the Salpeter's (1955) value. Mass segregation is
observed in both the clusters which may be due to the dynamical evolutions or
imprint of star formation processes or both.


title:
Simulating stochastically excited oscillations. The mode lifetime of xi
  Hya

abstract:
  The discovery of solar-like oscillations in the giant star xy Hya (G7III) was
reported by Frandsen et al. (2002). Their frequency analysis was very limited
due to alias problems in the data set (caused by single-site observations). The
extent to which the aliasing affected their analysis was unclear due to the
unknown damping time of the stellar oscillation modes. In this paper we
describe a simulator created to generate time series of stochastically excited
oscillations, which takes as input an arbitrary window function and includes
both white and non-white noise. We also outline a new method to compare a large
number of simulated time series with an observed time series to determine the
damping time, amplitude, and limited information on the degree of the
stochastically excited modes. For xi Hya we find the most likely amplitude to
be ~ 2 m/s, in good agreement with theory (Houdek & Gough, 2002), and the most
likely damping time to be ~ 2 days, which is much shorter than the theoretical
value of 15-20 days calculated by Houdek & Gough (2002).


title: Updated pulsation models for anomalous Cepheids

abstract:
  A theoretical investigation of the pulsation behavior of so-named
``anomalous'' Cepheids is presented. The study is based on nonlinear convective
pulsation models with $Z$=0.0001 and 0.0004, mass in the range 1.3-2.2 Mo and
various luminosity levels. Based on these computations, we derive period,
bolometric light curves and the edges of the instability strip, showing that a
variation of the metal abundance from Z=0.0001 to 0.0004 has quite small
effects on these quantities. Then, using bolometric corrections and
color-temperature transformations, we are able to provide the predicted
relations connecting pulsational properties (periods, amplitudes) with
magnitudes and colors in the various photometric bands. The theoretical
pulsational scenario is compared to observed anomalous Cepheids in dwarf
spheroidal galaxies and, in particular, the predicted mass-dependent
Period-Magnitude-Amplitude and Period-Magnitude-Color relations are used to
estimate individual mass values, as well as to discriminate between fundamental
(F) and first-overtone (FO) pulsators.


title: An explanation for metallicity effects on X-ray Binary properties

abstract:
  We show that irradiation induced stellar winds can explain two important
metallicity effects in X-ray binaries - the higher numbers and the softer
spectra of the X-ray binaries in metal rich globular clusters compared to the
metal poor ones. As has been previously noted by Iben, Tutukov and Fedorova,
the winds should be stronger at lower metallicity due to less efficient line
cooling. This will speed up the evolution of the LMXBs in metal poor clusters,
hence reducing their numbers. These winds can also provide extra material near
the accreting object which may create an intrinsic absorber to harden the X-ray
spectra of the metal poor cluster systems relative to the metal rich ones, as
suggested by observations. We outline some additional observational predictions
of the model.


title:
Accurate X-ray position of the Anomalous X-ray Pulsar XTE J1810-197 and
  identification of its likely IR counterpart

abstract:
  We report the accurate sub-arcsec X-ray position of the new Anomalous X-ray
Pulsar (AXP) XTE J1810-197, derived with a Chndra-HRC Target of Opportunity
observation carried out in November 2003. We also report the discovery of a
likely IR counterpart based on a VLT (IR band) Target of Opportunity
observation carried out in October 2003. Our proposed counterpart is the only
IR source (Ks=20.8) in the X-ray error circle. Its IR colors as well as the
X-ray/IR flux ratio, are consistent with those of the counterparts of all other
AXPs (at variance with field star colors). Deep Gunn-i band images obtained at
the 3.6m ESO telescope detected no sources down to a limiting magnitude of
24.3. Moreover, we find that the pulsed fraction and count rates of XTE
J1810-197 remained nearly unchanged since the previous Chandra and XMM-Newton
observations (2003 August 27th and September 8th, respectively). We briefly
discuss the implications of these results. In particular, we note that the
transient (or at least highly variable) nature of this AXP might imply a
relatively large number of hidden members of this class.


title: The Effect of aberration on polarization position angle of pulsars

abstract:
  The linear polarization position angle (PPA) of pulsar emission shows a wide
variety of structures, which deviates from the classical rotating vector model.
In this study we investigate the effect on the PPA due to emission arising from
a range of heights. We demonstrate that by appropriately choosing the emission
height we can reconstruct the PPA sweep across the integrated pulse profiles.


title: Chemical and mass evolution of galaxies

abstract:
  An introduction is given to projects investigating galaxy evolution
quantitatively by spectroscopic observations of very distant galaxies that have
weak apparent brightnesses and small sizes as it is feasible with 10m-class
telescopes like SALT. Such methods encompass scaling relations like the
Tully-Fisher and Fundamental Plane relations that can be utilized to determine
the luminosity evolution and mass assembly of galaxies. The stellar populations
can be analyzed with respect to age, metallicity, and chemical enrichment by
measureing absorption line strengths. Possible effects on galaxy evolution of
the environment in rich clusters of galaxies compared to the field are also
addressed. For each method, recent applications are presented like the
evolution of the TFR determined with 77 field spirals up to z=1, a study of the
internal kinematics of distant cluster spirals and a comparison of the stellar
populations of ellipticals in the field and in rich clusters at z=0.4.


title:
Searching for the relativistic Sunyaev-Zeldovich effect with the PLANCK
  experiment

abstract:
  Populations of relativistic electrons in clusters of galaxies should imprint
a characteristic spectral distortion signature on the Cosmic Microwave
Background photons - the relativistic Sunyaev-Zeldovich (SZ) effect. We
investigate how sensitive PLANCK and successor experiments will be in detecting
or constraining the total optical depth tau of relativistic electrons. We find
an expected sensitivity of PLANCK of sigma_tau ~ 2 10^-5 for an individual
cluster, which is too insensitive to detect even optimistic scenarios, which
predict tau ~ 10^-6 to 10^-7. However, by stacking the PLANCK-signal of all SZ
detectable clusters the relativistic SZ effect can be statistically probed to a
sensitivity level of sigma_tau ~ 10^-7. PLANCK successor experiments will be
able to probe even conservative scenarios of relativistic electron populations
in clusters of galaxies.


title:
The Stellar Composition of the Star Formation Region CMa R1 -- III. A
  new outburst of the Be star component in Z CMa

abstract:
  We report on a recent event in which, after more than a decade of slowly
fading, the visual brightness of the massive young binary Z CMa suddenly
started to rise by about 1 magnitude in December 1999, followed by a rapid
decline to its previous brightness over the next six months. This behaviour is
similar to that exhibited by this system around its eruption in February 1987.
A comparison of the intrinsic luminosities of the system with recent
evolutionary calculations shows that Z CMa may consist of a 16 M_sun B0 IIIe
primary star and a ~ 3 M_sun FUOr secondary with a common age of ~ 3 x 10^5 yr.
We also compare new high-resolution spectra obtained in Jan. and Feb. 2000,
during the recent rise in brightness, with archive data from 1991 and 1996. The
spectra are rich in emission lines, which originate from the envelope of the
early B-type primary star. The strength of these emission lines increased
strongly with the brightness of Z CMa. We interpret the collected spectral data
in terms of an accretion disc with atmosphere around the Herbig B0e component
of Z CMa, which has expanded during the outbursts of 1987 and 2000. A high
resolution profile of the 6300 A [O I] emission line, obtained by us in March
2002 shows an increase in flux and a prominent blue shoulder to the feature
extending to ~ -700 km/s, which was much fainter in the pre-outburst spectra.
We propose that this change in profile is a result of a strong change in the
collimation of a jet, as a result of the outburst at the start of this century.


title: RXJ1856.5-3754 and RXJ0720.4-3125 are P-Stars

abstract:
  P-stars are a new class of compact stars made of up and down quarks in
$\beta$-equilibrium with electrons in a chromomagnetic condensate. P-stars are
able to account for compact stars with $R \lesssim 6 Km$, as well as stars
comparable to canonical neutron stars. We show that P-stars once formed are
absolutely stable, for they cannot decay into neutron or strange stars. We
convincingly argue that the nearest isolated compact stars RXJ1856.5-3754 and
RXJ0720.4-3125 could be interpreted as P-stars with $M \simeq 0.8 M_{\bigodot}$
and $R \simeq 5 Km$.


title:
Neutral hydrogen surveys for high redshift galaxy clusters and
  proto-clusters

abstract:
  We discuss the possibility of performing blind surveys to detect large-scale
features of the universe using 21cm emission. Using instruments with approx.
5'-10' resolution currently in the planning stage, it should be possible to
detect virialized galaxy clusters at intermediate redshifts using the combined
emission from their constituent galaxies, as well as less overdense structures,
such as proto-clusters and the `cosmic web', at higher redshifts. Using
semi-analytic methods we compute the number of virialized objects and those at
turnaround which might be detected by such surveys. We find a surprisingly
large number of objects might be detected even using small (approx. 5%)
bandwidths and elaborate on some issues pertinent to optimising the design of
the instrument and the survey strategy. The main uncertainty is the fraction of
neutral gas relative to the total dark matter within the object. We discuss
this issue in the context of the observations which are currently available.


title: Dark Matter: Early Considerations

abstract:
  A review of the study of dark matter is given, starting with earliest studies
and finishing with the establishment of the standard Cold Dark Matter paradigm
in mid 1980-s. Particular attention is given to the collision of the classical
and new paradigms concerning the matter content of the Universe. Also the
amount of baryonic matter, dark matter and dark energy is discussed using
modern estimates.


title: Clusters and Superclusters in the Sloan and Las Campanas Surveys

abstract:
  We generate the 2-dimensional high-resolution density field of galaxies of
the Early Data Release of the Sloan Digital Sky Survey and the Las Campanas
Redshift Survey with a smoothing length 0.8 Mpc/h to extract clusters and
groups of galaxies, and a low-resolution field with a smoothing length 10 Mpc/h
to extract superclusters of galaxies. We investigate properties of density
field clusters and superclusters and compare the properties of these clusters
and superclusters with those of Abell clusters, and superclusters found on the
basis of Abell clusters. We found that clusters in a high-density environment
have a luminosity a factor of 5 - 10 higher than in a low-density environment.
Clusters and superclusters in the Northern slice of SDSS are much richer than
those in the Southern slice.


title: Detecting the Dusty Debris of Terrestrial Planet Formation

abstract:
  We use a multiannulus accretion code to investigate debris disks in the
terrestrial zone, at 0.7-1.3 AU around a 1 solar mass star. Terrestrial planet
formation produces a bright dusty ring of debris with a lifetime of at least 1
Myr. The early phases of terrestrial planet formation are observable with
current facilities; the late stages require more advanced instruments with
adaptive optics.


title: Interstellar Extinction in the Milky Way Galaxy

abstract:
  I review the basic properties of interstellar extinction in the Milky Way
galaxy, focusing primarily on the wavelength dependence within the IR through
UV spectral region. My primary goal is to review the evidence supporting the
idea that Galactic extinction curves can be considered a 1-parameter family
characterized by their value of R(V) = A(V)/E(B-V). Based on analysis of new
(i.e., 2MASS) and old (i.e., IUE) data for about 100 sightlines, I show that
the UV, optical, and IR wavelength regimes do display coherent variations, but
with too much intrinsic scatter to be considered truly correlated. A
1-parameter family can be constructed which illustrates these broad trends, but
very few individual sightlines are actually well-reproduced by such a family
and disagreement with the mean trends is not a sufficient condition for
``peculiarity.'' Only a very small number of extinction sightlines stand out as
truly peculiar. It is likely that simple variations in the mean grain size from
sightline to sightline are responsible for much of the coherent variability
seen in Galactic extinction, and might also explain the ``peculiar'' extinction
long-noted in the Magellanic Clouds.


title: Gravitating discs around black holes

abstract:
  Fluid discs and tori around black holes are discussed within different
approaches and with the emphasis on the role of disc gravity. First reviewed
are the prospects of investigating the gravitational field of a black
hole--disc system by analytical solutions of stationary, axially symmetric
Einstein's equations. Then, more detailed considerations are focused to middle
and outer parts of extended disc-like configurations where relativistic effects
are small and the Newtonian description is adequate.
  Within general relativity, only a static case has been analysed in detail.
Results are often very inspiring, however, simplifying assumptions must be
imposed: ad hoc profiles of the disc density are commonly assumed and the
effects of frame-dragging and completely lacking. Astrophysical discs (e.g.
accretion discs in active galactic nuclei) typically extend far beyond the
relativistic domain and are fairly diluted. However, self-gravity is still
essential for their structure and evolution, as well as for their radiation
emission and the impact on the environment around. For example, a nuclear star
cluster in a galactic centre may bear various imprints of mutual star--disc
interactions, which can be recognised in observational properties, such as the
relation between the central mass and stellar velocity dispersion.


title: Modeling AGN spectra with PHOENIX: a self-consistent approach

abstract:
  We find that spectra of certain Iron Low Ionization Broad Absorption Line
(FeLOBAL) QSOs, which are characterized by low--ionization emission and blue
shifted absorption lines, can be well matched with the spectral synthesis code
SYNOW. SYNOW is a resonance scattering code and assumes that line emission
comes from a single line forming region. This interpretation is novel as
traditionally line emission and absorption in BALQSOs are thought to come from
two different regions. We extend this analysis by using the detailed PHOENIX
code to model the spectra. We present a SYNOW fit and a preliminary model
result from PHOENIX.


title: The Universe is a Strange Place

abstract:
  This is a broad and in places unconventional overview of the strengths and
shortcomings of our standard models of fundamental physics and of cosmology.
The emphasis is on ideas that have accessible experimental consequences. It
becomes clear that the frontiers of these subjects share much ground in common.


title: The origin of non-thermal X-ray filaments and TeV emission in young SNRs

abstract:
  At the early, ejecta dominated, stage of supernova remnant (SNR) expansion a
fraction of the swept-up circumstellar magnetic field is dynamically compressed
to approximate equipartition at the contact discontinuity separating the SN
progenitor's wind (or the ISM) and the ejecta. We propose that the thin
non-thermal X-ray filaments observed by the Chandra satellite in several young
SNRs are associated with such ``pile-up'' of the magnetic field. We use a
one-dimensional diffusion-convection transport equation to describe the
propagation of non-thermal electrons near the contact discontinuity of a young
SNR and to calculate spatially resolved emission spectra in the X-ray and TeV
bands. The results suggest that the high-energy electrons are possibly
accelerated at the forward shock, and emitting efficiently only when they
diffuse into regions of high magnetic field near the contact discontinuity.
Much more likely, though, is that they are locally accelerated at the contact
discontinuity, in which case the acceleration cannot be related to Fermi-type
processes and should occur due to other plasma mechanisms. As a consequence,
the forward shock in young SNRs is inconspicuous and often unobservable,
similar to that in the Crab nebular.


title:
Chandra Observations of the Three Most Metal-Deficient Blue Compact
  Dwarf Galaxies known in the Local Universe, SBS 0335-052, SBS 0335-052W, and
  I Zw 18

abstract:
  We present an X-ray study of the three most metal-deficient blue compact
dwarf (BCD) galaxies known in the local Universe, based on deep Chandra
observations of SBS 0335-052 (0.025 solar abundance), SBS 0335-052W (0.02 solar
abundance) and I Zw 18 (0.02 solar abundance). All three are detected, with
more than 90% of their X-ray emission arising from point-like sources. The
0.5-10.0 keV luminosities of these point sources are in the range
(1.3-8.5)x1e39 erg/s. We interpret them to be single or a collection of
high-mass X-ray binaries, the luminosities of which may have been enhanced by
the low metallicity of the gas. There are hints of faint extended diffuse X-ray
emission in both SBS 0335-052 and I Zw 18, probably associated with the
superbubbles visible in both BCDs. The spectrum of I Zw 18 shows a OVIII
hydrogen-like emission line. The best spectral fit gives an O overabundance of
the gas in the X-ray point source by a factor of ~7 with respect to the Sun, or
a factor of ~350 with respect to the O abundance determined for the HII region.


title: Unraveling Brown Dwarf Origins

abstract:
  Brown dwarfs, which occupy a fuzzy gap in mass between stars and planets,
appear to be common both in the solar neighborhood and in star-forming regions.
Their origin is a topic of significant current interest and debate. Some
astronomers have suggested that brown dwarfs are stellar embryos, ejected from
newborn multiple star systems. Others argue that they form in the same manner
as stars, through fragmentation and collapse of interstellar clouds.
Observations of young brown dwarfs may help distinguish among different
scenarios for their formation. The recent discovery that many of them harbor
accreting disks of gas and dust points to a similar infancy for brown dwarfs
and Sun-like stars. Future infrared and millimeter observations, from
telescopes on the ground and in space, could provide more definitive tests.


title: Angular Correlations of the MeV Cosmic Gamma Ray Background

abstract:
  The measured cosmic gamma ray background (CGB) spectrum at MeV energies is in
reasonable agreement with the predicted contribution from type Ia supernovae
(SNIa). But the characteristic features in the SNIa gamma ray spectrum,
weakened by integration over source redshifts, are hard to measure, and
additionally the contributions from other sources in the MeV range are
uncertain, so that the SNIa origin of the MeV CGB remains unproven. Since
different CGB sources have different clustering properties and redshift
distributions, by combining the CGB spectrum and angular correlation
measurements, the contributions to the CGB could be identified and separated.
The SNIa CGB large-scale structure follows that of galaxies. Its rms
fluctuation at degree scales has a characteristic energy dependence, ranging
from $\sim 1%$ to order of unity and can be measured to several percent
precision by proposed future satellites such as the Advanced Compton Telescope.
With the identification of the SNIa contribution, the SNIa rate could be
measured unambiguously as a function of redshift up to $z \sim 1$, by combining
both the spectrum and angular correlation measurements, yielding new
constraints on the star formation rate to even higher redshifts. Finally, we
show that the gamma ray and neutrino backgrounds from supernovae should be
closely connected, allowing an important consistency test from the measured
data. Identification of the astrophysical contributions to the CGB would allow
much greater sensitivity to an isotropic high-redshift CGB contribution arising
in extra dimension or dark matter models.


title:
The Log-normal Distributions of Physical Quantities of Flare associated
  Coronal Mass Ejections (CMEs), and Flare/CME Model of Gamma-ray Bursts

abstract:
  We investigated the statistical distributions of physical quantities of solar
flares and associated coronal mass ejections (CMEs). We found that the
distributions of the X-ray peak fluxes of CME-related flares, their time
intervals, and speeds of associated CMEs are in good agreement with log-normal
distributions. One possible interpretation of this is that only large energetic
mass ejections can escape from the solar corona, which become CMEs in the
interplanetary space. This ``filtering effect'' may be the reason why
statistical distributions of some physical quantities are similar to log-normal
distribution. It is known that the distributions of several physical quantities
of gamma-ray bursts (GRBs) are also log-normal distributions, and that the time
variations of gamma-ray intensity in GRBs are very similar to those of hard
X-rays of solar flares. On the basis of these similarities and physical
consideration of magnetohydrodynamic properties of an accretion disk around a
black hole, which is supposed to be situated in the central engine of a GRB, we
propose a new model of the central engine of GRBs, the {\it flare/CME model},
in which GRBs are formed by nonsteady jets consisting of intermittent ejections
of mass (like solar CMEs) associated with reconnection events (like solar
flares) in the accretion disk corona. Such nonsteady MHD jets would produce
many shocks as well as local reconnection events far from the central engine.
In this model, only large energetic mass ejections can escape from the
accretion disk corona, so that statistical distributions of some physical
quantities are similar to log-normal distributions.


title: The Team Keck Treasury Redshift Survey of the GOODS-North Field

abstract:
  We report the results of an extensive imaging and spectroscopic survey in the
GOODS-North field completed using DEIMOS on the Keck II telescope. Observations
of 2018 targets in a magnitude-limited sample of 2911 objects to R=24.4 yield
secure redshifts for a sample of 1440 galaxies and AGN plus 96 stars. In
addition to redshifts and associated quality assessments, our catalog also
includes photometric and astrometric measurements for all targets detected in
our R-band imaging survey of the GOODS-North region. We investigate various
sources of incompleteness and find the redshift catalog to be 53% complete at
its limiting magnitude. The median redshift of z=0.65 is lower than in similar
deep surveys because we did not select against low-redshift targets. Comparison
with other redshift surveys in the same field, including a complementary
Hawaii-led DEIMOS survey, establishes that our velocity uncertainties are as
low as 40 km/s for red galaxies and that our redshift confidence assessments
are accurate. The distributions of rest-frame magnitudes and colors among the
sample agree well with model predictions out to and beyond z=1. We will release
all survey data, including extracted 1-D and sky-subtracted 2-D spectra, thus
providing a sizable and homogeneous database for the GOODS-North field which
will enable studies of large scale structure, spectral indices, internal galaxy
kinematics, and the predictive capabilities of photometric redshifts.