title: The Diversity of Gamma-Ray Bursts and the Surroundings of Massive Stars

abstract:
  The finding of a Type Ic supernova connected with GRB 030329 showed a massive
star origin for this burst, supporting evidence for this association in
previous bursts with lightcurve bumps at the appropriate time for a supernova.
Here, we explore the possibility that all long bursts have massive star
progenitors, interacting with either the freely expanding wind of the
progenitor or the shocked wind. We present models for the afterglows of GRB
020405 and GRB 021211, which are a challenge to wind interaction models.
Considering sources for which wind interaction models are acceptable, a range
of wind densities is required, from values typical of Galactic Wolf-Rayet stars
to values ~100 times smaller. The reason for the low densities is unclear, but
may involve low progenitor masses and/or low metallicities. If mass is a
factor, a low density event should be associated with a low mass supernova. The
interpretation of bursts apparently interacting with constant density media as
interaction with a shocked wind requires both a range of mass loss densities
and a range of external pressures. The highest pressures, p/k > 10^8 cm^{-3} K,
may be due to an extreme starburst environment, which would imply that the
burst is superposed on an active star forming region. Although the range of
observed events can be accomodated by the shocked wind theory, special
circumstances are necessary to bring this about. Finally, we consider the high
velocity, high ionization absorption features observed in some afterglow
spectra. If the features are circumstellar, the presence of the burst in a
starburst region may be important for the formation of clumps near the burst.


title: The H-alpha Light Curves and Spatial Distribution of Novae in M81

abstract:
  We present the results of a preliminary H-alpha survey of M81 for novae
conducted over a 5 month interval using the 5' field of view camera (WFCAM) on
the Calypso Telescope at Kitt Peak, AZ. We observed M81 nearly every clear
night during this interval, covering the entire galaxy, and discovered 12
novae. Our comprehensive time coverage allowed us to produce the most complete
set of H-alpha light curves for novae in M81 to date. A raw nova rate for M81
gives 23 yr^-1 which, because of the nature of our survey, is a hard lower
limit. An analysis of the completeness in our survey gives a corrected nova
rate of 30 yr^-1. This agrees well with the rate of 33 (+13,-8) yr^-1, derived
from Monte Carlo simulations using nova light curves and survey frame limits.
The spatial distribution of the novae we discovered follows the bulge light
much better than the disk or total light according to Kolmogorov - Smirnov
tests of their radial distributions. The asymmetry in the distribution of novae
across the major axis line of M81 implies a bulge-to-disk nova ratio of > 9 and
supports the idea that novae originate primarily in older stellar populations.


title: Cosmic Gravitational Shear from the HST Medium Deep Survey

abstract:
  We present a measurement of cosmic shear on scales ranging from $ 10\arcsec $
to $ 2\arcmin $ in 347 WFPC2 images of random fields. Our result is based on
shapes measured via image fitting and on a simple statistical technique;
careful calibration of each step allows us to quantify our systematic
uncertainties and to measure the cosmic shear down to very small angular
scales. The WFPC2 images provide a robust measurement of the cosmic shear
signal decreasing from $5.2% $ at $ 10\arcsec $ to $2.2% $ at $ 130\arcsec $.


title:
Formation of First Stars Triggered by Collisions and Shockwaves:
  Prospect for High Star Formation Efficiency and High Ionizing Photon Escape
  Fraction

abstract:
  We show that large, high-redshift (z>10) galaxies with virial temperature in
excess of 10^4K may be mostly comprised of cold atomic clouds which were
formerly minihalos. These clouds move at a speed of 15-30km/s and collide with
one another on a time scale of 10^7yr. The supersonic collisions result in
spatially distributed star formation with high efficiency. We then show that
most, subsequent star formation in cold atomic clouds may be triggered by
shockwaves launched from the first stars formed in collisions. Those
shockwave-compressed clouds are even more widespread spatially because of large
imparted velocities and some can possibly escape into the intergalactic medium.
More importantly, with respect to cosmological reionization, widespread star
formation would allow a much higher ionizing photon escape fraction. These
favorable conditions may form the physical basis to enable the standard
cosmological model to produce a reasonably high Thomson optical depth
\tau_e=0.10-0.14. A chain reaction of star formation in minihalos in the
intergalactic space may be triggered by explosions in the intergalactic medium,
if minihalos are strongly clustered. In this case, a still higher \tau_e would
be achievable.


title: A review of the theory of incompressible MHD turbulence

abstract:
  This brief invited review provides an introduction to key ideas in the theory
of incompressible magnetohydrodynamic (MHD) turbulence.


title:
Particle acceleration by slow modes in strong compressible MHD
  turbulence, with application to solar flares

abstract:
  Energetic particles that undergo strong pitch-angle scattering and diffuse
through a plasma containing strong compressible MHD turbulence undergo
diffusion in momentum space with diffusion coefficient Dp. In this paper, the
contribution of slow modes to Dp is calculated assuming the rms turbulent
velocity is of order the Alfven speed. The energy spectrum of accelerated
particles is derived assuming slow modes make the dominant contribution to Dp,
taking into account Coulomb losses and particle escape from the acceleration
region with an energy-independent escape time. The results are applied to solar
flares.


title:
Acceleration of energetic particles by large-scale compressible
  magnetohydrodynamic turbulence

abstract:
  Fast particles diffusing along magnetic field lines in a turbulent plasma can
diffuse through and then return to the same eddy many times before the eddy is
randomized in the turbulent flow. This leads to an enhancement of particle
acceleration by large-scale compressible turbulence relative to previous
estimates in which isotropic particle diffusion is assumed.


title:
Cosmic Star Formation History from Local Observations and an Outline for
  Galaxy Formation and Evolution

abstract:
  The goal of this investigation is to reconstruct the cosmic star formation
rate density history from local observations and in doing so to gain insight
into how galaxies might have formed and evolved. A new chemical evolution model
is described which accounts for the formation of globular clusters as well as
the accompanying field stars. When this model is used in conjunction with the
observed age metallicity relations for the clusters and with input which allows
for the formation of the nearly universally observed bimodal distribution of
globular clusters, star formation rates are obtained. By confining attention to
a representative volume of the local universe, these rates allow a successful
reconstruction of the Madau plot while complementary results similtaneously
satisfy many local cosmological constraints. A physical framework for galaxy
formation is presented which incorporates the results from this chemical
evolution model and assumes an anisotropic collapse. In addition to providing
the `classical' halo, bulge and disk components, the model also predicts a new
stellar halo component with peak [Fe/H] ~ -0.8 and disk-like angular momentum
and allows for the formation of a thick disk as outlined by the group of metal
rich globular clusters. Milky Way counterparts of the latter two components are
identified.


title: A New Nucleosynthesis Constraint on the Variation of G

abstract:
  Big Bang Nucleosynthesis can provide, via constraints on the expansion rate
at that time, limits on possible variations in Newton's Constant, $G$. The
original analyses were performed before an independent measurement of the
baryon-to-photon ratio from the cosmic microwave background was available.
Combining this with recent measurements of the primordial deuterium abundance
in quasar absorption systems now allows one to derive a new tighter constraint
on $G$ without recourse to considerations of helium or lithium abundances. We
find that, compared to todays value, $G_0$, $G_{BBN}/G_0=1.01^{+0.20}_{-0.16}$
at the 68.3% confidence level. If we assume a monotonic power law time
dependence, $G\propto t^{-\alpha}$, then the constraint on the index is $-0.004
< \alpha < 0.005$. This would translate into $-3\times10^{-13} \textrm{yr}^{-1}
< (\dot G/G)_{\textrm{today}} < 4 \times 10^{-13} \textrm{yr}^{-1}$.


title: Probing the Magnetic Field with Molecular Ion Spectra

abstract:
  Observations of the effect of the magnetic field on its environment are
usually achieved with techniques which rely on the interaction with the spin of
the particles under study. Because of the relative weakness of this effect,
extraction of the field characteristics proves to be a most challenging task.
We take a totally different approach to the problem and show that the
manifestation of the magnetic field can be directly observed by means of a
comparison of the spectra of molecular ions with those of neutral molecules.
This takes advantage of the strong cyclotron interaction between the ions and
the field, but requires the presence of flows or turbulent motion in the gas.
We compare our theory to data obtained on the OMC-1, OMC-2, OMC-3 and DR21(OH)
molecular clouds.


title: Probing the Magnetic Field with Molecular ion Spectra. II

abstract:
  We present further observational evidence in support of our earlier proposal
(Houde et al. 2000) for detecting the presence of the magnetic field in
molecular clouds by comparing spectra of molecular ions with those of neutral
molecules. The ion lines tend to be narrower and do not show the wings due to
flows, when the magnetic field is sufficiently strong. We obtained spectra for
the optically thin lines of the H13CN and H13CO+ species in a sample of ten
molecular clouds and found the results to be in agreement with our previous
observations of the main isotopic species, HCN and HCO+, made in OMC-1, OMC-2,
OMC-3 and DR21OH, thus eliminating the possibility of optical depth effects
playing a role in the ion line narrowing. HCS+ was also detected in four of
these star forming regions. We also discuss previously published results by
(Benson et al. 1998) of N2H+ detections in a large sample of dark clouds. We
show that the similarity in line widths between ion and neutral species in
their sample is consistent with the relatively small amount of turbulence and
other flows observed in these clouds.


title: Tunguska genetic anomaly and electrophonic meteors

abstract:
  One of great mysteries of the Tunguska event is its genetic impact. Some
genetic anomalies were reported in the plants, insects and people of the
Tunguska region. Remarkably, the increased rate of biological mutations was
found not only within the epicenter area, but also along the trajectory of the
Tunguska Space Body (TSB). At that no traces of radioactivity were found, which
could be reliably associated with the Tunguska event. The main hypotheses about
the nature of the TSB, a stony asteroid, a comet nucleus or a carbonaceous
chondrite, readily explain the absence of radioactivity but give no clues how
to deal with the genetic anomaly. A choice between these hypotheses, as far as
the genetic anomaly is concerned, is like to the choice between ``blue devil,
green devil and speckled devil'', to quote late Academician N.V. Vasilyev.
However, if another mysterious phenomenon, electrophonic meteors, is evoked,
the origin of the Tunguska genetic anomaly becomes less obscure.


title: Inner Size of a Dust Torus in the Seyfert 1 Galaxy NGC 4151

abstract:
  The most intense monitoring observations yet made were carried out on the
Seyfert 1 galaxy NGC 4151 in the optical and near-infrared wave-bands. A lag
from the optical light curve to the near-infrared light curve was measured. The
lag-time between the V and K light curves at the flux minimum in 2001 was
precisely 48+2-3 days, as determined by a cross-correlation analysis. The
correlation between the optical luminosity of an active galactic nucleus (AGN)
and the lag-time between the UV/optical and the near-infrared light curves is
presented for NGC 4151 in combination with previous lag-time measurements of
NGC 4151 and other AGNs in the literature. This correlation is interpreted as
thermal dust reverberation in an AGN, where the near-infrared emission from an
AGN is expected to be the thermal re-radiation from hot dust surrounding the
central engine at a radius where the temperature equals to that of the dust
sublimation temperature. We find that the inner radius of the dust torus in NGC
4151 is $\sim $ 0.04 pc corresponding to the measured lag-time, well outside
the broad line region (BLR) determined by other reverberation studies of the
emission lines.


title:
First MHD Simulation of Collapse and Fragmentation of Magnetized
  Molecular Cloud Cores

abstract:
  This is the first paper about the fragmentation and mass outflow in the
molecular cloud by using three-dimensional MHD nested-grid simulations. The
binary star formation process is studied paying particular attention to the
fragmentation of a rotating magnetized molecular cloud. We assume an isothermal
rotating and magnetized cylindrical cloud in hydrostatic balance.
Non-axisymmetric as well as axisymmetric perturbations are added to the initial
state and the subsequent evolutions are studied. The evolution is characterized
by three parameters: the amplitude of the non-axisymmetric perturbations, the
rotation speed, and the magnetic field strength. As a result, it is found that
non-axisymmetry hardly evolves in the early phase, but begins to grow after the
gas contracts and forms a thin disk. Disk formation is strongly promoted by the
rotation speed and the magnetic field strength. There are two types of
fragmentation: fragmentation from a ring and that from a bar. Thin adiabatic
cores fragment if a thickness is smaller than 1/4 of the radius. For the
fragments to survive, they should be formed in a heavily elongated barred core
or a flat round disk. In the models showing fragmentation, outflows from
respective fragments are found as well as those driven by the rotating bar or
the disk.


title: Smashing the Guitar: An Evolving Neutron Star Bow Shock

abstract:
  The Guitar nebula is a spectacular example of an H-alpha bow shock nebula
produced by the interaction of a neutron star with its environment. The radio
pulsar B2224+65 is traveling at ~800--1600 km/s (for a distance of 1--2 kpc),
placing it on the high-velocity tail of the pulsar velocity distribution. Here
we report time evolution in the shape of the Guitar nebula, the first such
observations for a bow shock nebula, as seen in H-alpha imaging with the Hubble
Space Telescope. The morphology of the nebula provides no evidence for
anisotropy in the pulsar wind, nor for fluctuations in the pulsar wind
luminosity. The nebula shows morphological changes over two epochs spaced by
seven years that imply the existence of significant gradients and
inhomogeneities in the ambient interstellar medium. These observations offer
astrophysically unique, in situ probes of length scales between 5E-4 pc and
0.012 pc. Model fitting suggests that the nebula axis -- and thus the
three-dimensional velocity vector -- lies within 20 degrees of the plane of the
sky, and also jointly constrains the distance to the neutron star and the
ambient density.


title: First signatures of strong differential rotation in A-type stars

abstract:
  We reanalyzed high quality spectra of 158 stars of spectral types A0--F1 and
$v \sin{i}$ between 60 and 150 km s$^{-1}$. Using a Least Squares Deconvolution
technique we extracted high $S/N$ broadening profiles and determined the loci
of the Fourier transform zeros $q_{1}$ and $q_{2}$ where the $S/N$-ratio was
high enough. The values of $v \sin{i}$ were redetermined and found to be
consistent with the values derived by \cite{Royer02a}. For 78 stars $q_{2}$
could be determined and the ratio $q_{2}/q_{1}$ was used as a shape parameter
sensitive for solar-like differential rotation (Equator faster than Pole). 74
of the 78 stars have values of $q_{2}/q_{1}$ consistent with solid body
rotation; in four of the 78 cases, values of $q_{2}/q_{1}$ are not consistent
with rigid rotation. Although these stars may be binaries, none of the profiles
shows signatures of a companion. The Fourier transforms do not indicate any
distortions and the broadening profiles can be considered due to single
objects. One of those candidates may be an extremely rapid rotator seen
pole-on, but for the other three stars of spectral types as early as A6,
differential rotation seems to be the most plausible explanation for the
peculiar profiles.


title: The Size of the Longest Filaments in the Universe

abstract:
  We analyze the filamentarity in the Las Campanas redshift survey (LCRS) and
determine the length scale at which filaments are statistically significant.
The largest length-scale at which filaments are statistically significant, real
objects, is between 70 to $80 h^{-1}$Mpc, for the LCRS $-3^o$ slice.
Filamentary features longer than $80 h^{-1}$Mpc, though identified, are not
statistically significant; they arise from chance alignments. For the five
other LCRS slices, filaments of lengths $50 h^{-1}$Mpc to $70 h^{-1}$Mpc are
statistically significant, but not beyond. These results indicate that while
individual filaments up to $80 h^{-1}$Mpc are statistically significant, the
impression of structure on larger scales is a visual effect. On scales larger
than $80 h^{-1}$Mpc the filaments interconnect by statistical chance to form
the filament-void network. The reality of the $80 h^{-1}$Mpc features in the
$-3^o$ slice make them the longest coherent features in the LCRS. While
filaments are a natural outcome of gravitational instability, any numerical
model attempting to describe the formation of large scale structure in the
universe must produce coherent structures on scales that match these
observations.


title: Astrophysical Neutrino Telescopes

abstract:
  This review describes telescopes designed to study neutrinos from
astrophysical sources. These sources include the Sun and Supernovae emitting
neutrino energies up to tens of MeV, atmospheric neutrino sources caused by
cosmic ray interactions and other sources generating neutrino energies ranging
up to $1\times 10^{20}$ eV. Measurements with these telescopes also provide
information on neutrino properties including clear evidence for neutrino flavor
change. Telescopes in operation in the past and present are described, along
with plans for future instruments to expand this rapidly growing field of
particle astrophysics.


title:
The XMM--NEWTON Omega Project: I. The X-ray Luminosity - Temperature
  Relation at z>0.4

abstract:
  (abridged) We describe XMM-Newton Guaranteed Time observations of a sample of
eight high redshift (0.45<z<0.62) clusters. The goal of these observations was
to measure the luminosity and the temperature of the clusters to a precision of
\~10%, leading to constraints on the possible evolution of the
luminosity--temperature relation, and ultimately on the values of the matter
density, Omega_M and, to a lesser extent, the cosmological constant Omega_L.
The clusters were drawn from the SHARC and 160 Square Degree (160SD) ROSAT
surveys. Here we describe our data analysis techniques and present, for the
first time with XMM-Newton,Lx-Tx relation. For each of the eight clusters in
the sample, we have measured total bolometric luminosities, performed
beta-model fits to the radial surface profiles and made spectral fits to a
single temperature isothermal model. We describe data analysis techniques that
pay particular attention to background mitigation. Characterizing the Lx-Tx
relation as Lx = L_{6} (T/6keV)^{alpha},we find L_{6}=16.8 +7.6/-5.2 10^{44}
erg/s and alpha=2.7 +/-0.4 for a EdS H=50 cosmology at a typical redshift z
=0.55. Comparing with the low redshift study by Markevitch, assuming L-T to
evolve as (1+z)^A, we find A=0.68 +/-0.26 for the same cosmology and A=1.52
+0.26/-0.27 for a concordance cosmology. We conclude that there is now evidence
from both XMM-Newton and Chandra for an evolutionary trend in the L-T relation.
Our observations lend support to the robustness and completeness of the SHARC
and 160SD surveys.


title:
Constraints On the Diffusive Shock Acceleration From the Nonthermal
  X-ray Thin Shells In SN1006 NE Rim

abstract:
  Characteristic scale lengths of nonthermal X-rays from the SN1006 NE rim,
which are observed by Chandra, are interpreted in the context of the diffusive
shock acceleration on the assumption that the observed spatial profile of
nonthermal X-rays corresponds to that of accelerated electrons with energies of
a few tens of TeV. To explain the observed scale lengths, we construct two
simple models with a test particle approximation, where the maximum energy of
accelerated electrons is determined by the age of SN1006 (age-limited model) or
the energy loss (energy loss-limited model), and constrain the magnetic field
configuration and the diffusion coefficients of accelerated electrons. When the
magnetic field is nearly parallel to the shock normal, the magnetic field
should be in the range of 20-85 micro Gauss and highly turbulent both in
upstream and downstream, which means that the mean free path of accelerated
electrons is on the order of their gyro-radius (Bohm limit). This situation can
be realized both in the age-limited and energy loss-limited model. On the other
hand, when the magnetic field is nearly perpendicular to the shock normal,
which can exist only in the age-limited case, the magnetic field is several
micro Gauss in the upstream and 14-20 micro Gauss in the downstream, and the
upstream magnetic field is less turbulent than the downstream.


title:
Age-dating a star-burst with Gemini/CIRPASS observations of the core of
  M83

abstract:
  We present preliminary results from a set of near-IR integral field
spectroscopic observations of the central, star-burst, regions of the barred
spiral galaxy M83, obtained with CIRPASS on Gemini-S. We present maps in the
Paschen-Beta and [FeII]1.257um emission lines which appear surprisingly
different. We outline the procedure in which we will use Paschen-Beta emission
line strengths and measures of CO absorption to determine the relative and
absolute ages of individual star-forming knots in the central kpc region of
M83.


title:
Abundance Analysis of Turn-Off and Early Subgiant Stars in the Globular
  Cluster 47 Tuc (NGC 104)

abstract:
  We used the UVES spectrograph on Kueyen (VLT UT2) to perform the abundance
analysis of stars at the base of the giant branch (RGB) and at the main
sequence turn-off in the globular cluster 47 Tuc (NGC 104). High dispersion
spectra (R ~ 40,000) for 3 dwarfs and 9 subgiants were analyzed. We found an
overall [Fe/H] value of -0.67 +/-0.01 +/-0.04, rms=0.05 dex. The mean value
obtained from stars at the base of the RGB is virtually the same as that
obtained from the dwarfs. Na and O abundances show a star-to-star scatter and
are anti-correlated, not unlike previous finding in more metal-poor clusters.
The extension of the anticorrelation is not as extreme as found in other
clusters, but it is clearly present in unevolved stars. Al abundances do not
show a significant spread; this could be indicative that p-captures in high
temperature regions are less likely to occur in metal-rich clusters. The
[alpha/Fe] ratios suggest a slight excess of Ti with respect to field stars of
similar metallicities. Finally, we found an enhanced odd-even effect for
Fe-group elements. In particular, the [Mn/Fe] ratio is almost 0.2 dex deficient
with respect to the mean value of the dissipative component of field stars in
the solar neighborhood. While the theoretical and observational framework for
Mn is still poorly understood, the chemistry of 47 Tuc, coupled with its
kinematics and its somewhat younger age, might give hints favouring an origin
in a formely independent, possibly larger, subsystem of our Galaxy.


title: The visible matter - dark matter coupling

abstract:
  In the inner parts of spiral galaxies, of high or low surface brightness,
there is a close correlation between rotation curve shape and light
distribution. For any feature in the luminosity profile there is a
corresponding feature in the rotation curve and vice versa. This implies that
the gravitational potential is strongly correlated with the distribution of
luminosity: either the luminous mass dominates or there is a close coupling
between luminous and dark matter. In a similar way, the declining rotation
curves observed in the outer parts of high luminosity systems are a clear
signature of the stellar disk which either dominates or traces the distribution
of mass.
  The notion that the baryons are dynamically important in the centres of
galaxies, including LSBs, undermines the whole controversy over the cusps in
CDM halos and the comparison with the observations. If the baryons dominate in
the central regions of all spirals, including LSBs, how can the CDM profiles be
compared with the observations? Alternatively, if the baryons do not dominate
but simply trace the DM distribution, why, in systems of comparable luminosity,
are some DM halos cuspy (like the light) and others (also like the light) are
not?


title:
The Average Magnetic Field Strength in Molecular Clouds: New Evidence of
  Super-Alfvenic Turbulence

abstract:
  The magnetic field strength in molecular clouds is a fundamental quantity for
theories of star formation. It is estimated by Zeeman splitting measurements in
a few dense molecular cores, but its volume--averaged value within large
molecular clouds (over several parsecs) is still uncertain. In this work we
provide a new method to constrain the average magnetic field strength in
molecular clouds. We compare the power spectrum of gas density of molecular
clouds with that of two $350^3$ numerical simulations of supersonic MHD
turbulence. The numerical simulation with approximate equipartition of kinetic
and magnetic energies (model A) yields the column density power spectrum
$P(k)\propto k^{-2.25\pm 0.01}$, the super--Alfv\'{e}nic simulation (model B)
$P(k)\propto k^{-2.71\pm 0.01}$. The column density power spectrum of the
Perseus, Taurus and Rosetta molecular cloud complexes is found to be well
approximated by a power law, $P_{\rm o}(k)\propto k^{-a}$, with $a=2.74\pm
0.07$, $2.74\pm 0.08$ and $2.76\pm 0.08$ respectively. We conclude that the
observations are consistent with the presence of super--Alfv\'{e}nic turbulence
in molecular clouds (model B) while model A is inconsistent (more than 99%
confidence) with the observations.


title: Radial Velocity Studies of Close Binary Stars. IX

abstract:
  Radial-velocity measurements and sine-curve fits to the orbital velocity
variations are presented for the eighth set of ten close binary systems: AB
And, V402 Aur, V445 Cep, V2082 Cyg, BX Dra, V918 Her, V502 Oph, V1363 Ori, KP
Peg, V335 Peg. Half of the systems (V445 Cep, V2082 Cyg, V918 Her, V1363 Ori,
V335 Peg) were discovered photometrically by the Hipparcos mission and all
systems are double-lined (SB2) contact binaries. The broadening function method
permitted improvement of the orbital elements for AB And and V502 Oph. The
other systems have been observed for radial velocity variations for the first
time; in this group are five bright (V<7.5) binaries: V445 Cep, V2082 Cyg, V918
Her, KP Peg and V335 Peg. Several of the studied systems are prime candidates
for combined light and radial-velocity synthesis solutions.


title: The Time Dependence of Fundamental Constants and Planck Scale Physics

abstract:
  A real aether model of the vacuum proposed by Allen Rothwarf based upon a
degenerate Fermion fluid of polarizable particle-antiparticle pairs, leads to a
big bang model of the universe where the velocity of light varies inversely
with the square root of the cosmological time. Here, this model is used to
determine the time dependence of certain fundamental constants, i.e.
permittivity, permeability of free space : the Gravitational constant, and the
Planck units: length, time and mass.


title: A New Non-Parametric Approach to Galaxy Morphological Classification

abstract:
  We present two new non-parametric methods for quantifying galaxy morphology:
the relative distribution of the galaxy pixel flux values (the Gini coefficient
or G) and the second-order moment of the brightest 20% of the galaxy's flux
(M20). We test the robustness of G and M20 to decreasing signal-to-noise and
spatial resolution, and find that both measures are reliable to within 10% at
average signal-to-noise per pixel greater than 3 and resolutions better than
1000 pc and 500 pc, respectively. We have measured G and M20, as well as
concentration (C), asymmetry (A), and clumpiness (S) in the rest-frame
near-ultraviolet/optical wavelengths for 150 bright local "normal" Hubble type
galaxies (E-Sd) galaxies and 104 0.05 < z < 0.25 ultra-luminous infrared
galaxies (ULIRGs).We find that most local galaxies follow a tight sequence in
G-M20-C, where early-types have high G and C and low M20 and late-type spirals
have lower G and C and higher M20. The majority of ULIRGs lie above the normal
galaxy G-M20 sequence, due to their high G and M20 values. Their high Gini
coefficients arise from very bright nuclei, while the high second-order moments
are produced by multiple nuclei and bright tidal tails. All of these features
are signatures of recent and on-going mergers and interactions. We also find
that in combination with A and S, G is more effective than C at distinguishing
ULIRGs from the "normal" Hubble-types. Finally, we measure the morphologies of
45 1.7 < z < 3.8 galaxies from HST NICMOS observations of the Hubble Deep Field
North. We find that many of the z $\sim$ 2 galaxies possess G and A higher than
expected from degraded images of local elliptical and spiral galaxies, and have
morphologies more like low-redshift single nucleus ULIRGs.


title:
The Alignment of the Magnetic Field and Collimated Outflows in
  Star-forming Regions: the Case of NGC 2071

abstract:
  The magnetic field is believed to play a crucial role in the process of star
formation. From the support it provides during the initial collapse of
molecular clouds to the creation of strong collimated jets responsible for
large mass losses, current theories predict its importance in many different
stages during the formation of stars. Here we report on observational evidence
which tests one aspect that can be inferred from these theories: the alignment
between the local magnetic field and collimated bipolar outflows in such
environments. There is good evidence of an alignment in the case of NGC 2071.


title:
On the Measurement of the Magnitude and Orientation of the Magnetic
  Field in Molecular Clouds

abstract:
  We demonstrate that the combination of Zeeman, polarimetry and ion-to-neutral
molecular line width ratio measurements permits the determination of the
magnitude and orientation of the magnetic field in the weakly ionized parts of
molecular clouds. Zeeman measurements provide the strength of the magnetic
field along the line of sight, polarimetry measurements give the field
orientation in the plane of the sky and the ion-to-neutral molecular line width
ratio determines the angle between the magnetic field and the line of sight. We
apply the technique to the M17 star-forming region using a HERTZ 350 um
polarimetry map and HCO+-to-HCN molecular line width ratios to provide the
first three-dimensional view of the magnetic field in M17.


title:
Fragmentation and the formation of primordial protostars: the possible
  role of Collision Induced Emission

abstract:
  The mechanisms which could lead to chemo-thermal instabilities and
fragmentation during the formation of primordial protostars are investigated
analytically. We introduce approximations for H2 cooling rates bridging the
optically thin and thick regimes. These allow us to discuss instabilities up to
densities when protostars become optically thick to continuum radiation
(n~10^16 cm^-3). During the collapse, instability arises at two different
stages: at low density (n~10^8-10^11 cm^-3), it is due to fast 3-body reactions
converting H into H2; at high density (n>10^13 cm^-3), it is due to Collisional
Induced Emission (CIE). In agreement with the 3D simulations, we find that the
instability at low densities cannot lead to fragmentation, because fluctuations
do not survive turbulent mixing, and because their growth is slow. The
situation at high density is similar. The CIE-induced instability is as weak as
the low density one, with similar ratios of growth and dynamical time scales.
Fluctuation growth time is longer than free fall time, and fragmentation seems
unlikely. One then expects the first stars to be massive, not to form binaries
nor harbour planets. Nevertheless, full 3D simulations are required. They could
become possible using simplified estimates of radiative transfer effects, which
we show to work very well in the 1D case. This indicates that the effects of
radiative transfer during the initial stages of formation of primordial
protostars can be treated as local corrections to cooling. (Abridged)


title: An X-ray Selected AGN at z=4.6 Discovered by the CYDER Survey

abstract:
  We present the discovery of a high redshift, X-ray selected AGN by the
Calan-Yale Deep Extragalactic Research (CYDER) survey: CXOCY J033716.7-050153,
located at $z=4.61$, the second high redshift AGN discovered by this survey.
Here, we present its optical, near-IR and X-ray properties and compare it with
other optical and X-ray selected high redshift AGN. The optical luminosity of
this object is significantly lower than most optically selected high redshift
quasars. It also has a lower rest frame UV to X-ray emission ratio than most
known quasars at this redshift. This mild deviation can be explained either by
dust obscuring the UV radiation of a normal radio quiet AGN emitting at 10% of
its Eddington luminosity or because this is intrinsically a low luminosity
radio loud AGN, with a super-massive Black Hole of $\sim 10^8M_\sun$ emitting
at 1% of its Eddington luminosity. Deep radio observations can discriminate
between these two hypotheses.


title:
Cosmological Evolution of Heavy Element and Molecular Hydrogen
  Abundances

abstract:
  Spectroscopic observations of distant quasars have resulted in the detection
of molecular hydrogen in intervening damped Lyman-alpha absorption clouds
(DLAs). We use observations compiled from different experimental groups to show
that the molecular hydrogen abundance exhibits a dramatic increase over a
cosmological time period corresponding to 13% to 24% of the age of the
universe. We also tentatively show that the heavy element abundances in the
same gas clouds exhibit a faster and more well-defined cosmological evolution
compared to the general DLA population over the same time baseline. We argue
that this latter point is unsurprising, because the general DLA population
arises in a wide variety of galaxy types and environments, and thus a spans
broad range of ISM gas-phases and abundances at the same cosmic time. DLAs
exhibiting H2 absorption may therefore circumvent this problem, efficiently
identifying a narrower class of objects, and provide a more sensitive probe of
cosmological chemical evolution.


title: Afterglow Light Curves of Jetted Gamma-ray Burst Ejecta in Stellar Winds

abstract:
  Optical and radio afterglows arising from the shocks by relativistic conical
ejecta running into pre-burst massive stellar winds are revisited. Under the
homogeneous thin-shell approximation and a realistic treatment for the lateral
expansion of jets, our results show that a notable break exists in the optical
light curve in most cases we calculated in which the physical parameters are
varied within reasonable ranges. For a relatively tenuous wind which cannot
decelerate the relativistic jet to cause a light curve break within days, the
wind termination shock due to the ram pressure of the surrounding medium occurs
at a small radius, namely, a few times 10^{17} cm. In such a structured wind
environment, the jet will pass through the wind within several hours and run
into the outer uniform dense medium. The resulting optical light curve flattens
with a shallower drop after the jet encounters the uniform medium, and then
declines deeply, triggered by runaway lateral expansion.


title: Large Radio Astronomy: next 70 Years Step

abstract:
  Some attempts to predict the very distant future of Radio Astronomy are
given. It is not easy to predict a list of the first priority problems which
may appear, but the facilities potential is more predictable. It is suggested,
that in addition to the "dedicated for Radio Astronomy", facilities may be
extended greatly by integration with the next generation living standards
facilities, connected with People-to-People communications through the global
networks and by incorporating of the "Natural facilities", such as grav.
lensing, maser amplification in the ISM etc. As an examples of the extreme
cases of the $10^9 m^2$ class of the new generation Radio Telescopes,
utilization of the personal dipole size communication facilities by SKA type
instrument, and array from the asteroids first "Frehnel zones" will be
mentioned. Radio Astronomy from the secondary to optical facilities tool will
be the only tool in the exploration of the $z>10$ Universe. The reality of all
predictions depend mostly on the way, the Civilization will prefer : "Ahead, to
HOMO SAPIENCE" or "BACK TO PRIMATES".


title: Covariant Magnetoionic Theory II: Radiative Transfer

abstract:
  Accretion onto compact objects plays a central role in high energy
astrophysics. In these environments, both general relativistic and plasma
effects may have significant impacts upon the spectral and polarimetric
properties of the accretion flow. In paper I we presented a fully general
relativistic magnetoionic theory, capable of tracing rays in the geometric
optics approximation through a magnetised plasma in the vicinity of a compact
object. In this paper we discuss how to perform polarised radiative transfer
along these rays. In addition we apply the formalism to a barotropic thick disk
model, appropriate for low luminosity active galactic nuclei. We find that it
is possible to generate large fractional polarisations over the innermost
portions of the accretion flow, even when the emission mechanism is
unpolarised. This has implications for accreting systems ranging from pulsars
and X-ray binaries to AGN.


title: The Inner Density Cusp of Cold Dark Matter Halos

abstract:
  I report recent results of numerical simulations designed to study the inner
structure of Cold Dark Matter (CDM) halos. This work confirms the proposal of
Navarro, Frenk & White (NFW) that the shape of LambdaCDM halo mass profiles
differs strongly from a power law and is approximately independent of mass. The
logarithmic slope of the spherically-averaged density profile, as measured by
beta=-dln(rho)/dlnr, decreases monotonically towards the center, becomes
shallower than isothermal (beta<2) inside a characteristic radius, r_{-2}, and
shows no evidence for convergence to a well-defined asymptotic value (beta_0)
at the center. The dark mass contained within the innermost radius resolved by
the simulations places strong constraints on beta_0; cusps as steep as r^{-1.5}
are clearly ruled out in our highest resolution simulations. A profile where
the radial dependence of the slope is a simple power law, beta(r)\propto
r^{\alpha}, approximates the structure of halos better than the NFW profile and
so may minimize errors when extrapolating our results inward to radii not yet
reliably probed by numerical simulations. We compare the spherically-averaged
circular velocity (V_c) profiles to the rotation curves of low surface
brightness (LSB) galaxies in the samples of de Blok et al and Swaters et al.
The V_c profiles of simulated CDM halos are generally consistent with the
rotation curves of LSB galaxies, but there are also some clearly discrepant
cases. This disagreement has been interpreted as excluding the presence of
cusps, but it may also just reflect the difference between circular velocity
and rotation speed likely to arise in gaseous disks embedded within realistic
triaxial halos.


title:
Separating Thermal and Non-Thermal X-Rays in Supernova Remnants II:
  Spatially Resolved Fits to SN1006 AD

abstract:
  We present a spatially resolved spectral analysis of full ASCA observations
of the remnant of the supernova of 1006 AD. This remnant shows both nonthermal
X-ray emission from bright limbs, generally interpreted as synchrotron emission
from the loss-steepened tail of the nonthermal electron population also
responsible for radio emission, and thermal emission from elsewhere in the
remnant. In earlier work, we showed that the spatially integrated spectrum was
well described by a theoretical synchrotron model in which shock acceleration
of electrons was limited by escape, in combination with thermal models
indicating high levels of iron from ejecta. Here we use new spatially resolved
subsets of the earlier theoretical nonthermal models for the analysis. We find
that emission from the bright limbs remains well described by those models, and
refine the values for the characteristic break frequency. We show that
differences between the northeast and southwest nonthermal limbs are small, too
small to account easily for the presence of the northeast limb, but not the
southwest, in TeV gamma-rays. Comparison of spectra of the nonthermal limbs and
other regions confirms that simple cylindrically symmetric nonthermal models
cannot describe the emission, and we put limits on nonthermal contributions to
emission from the center and the northwest and southeast limbs. We can rule out
solar-abundance models in all regions, finding evidence for elevated
abundances. However, more sophisticated models will be required to accurately
characterize these abundances.


title: Gamma-Ray Bursts are Produced Predominately in the Early Universe

abstract:
  It is known that some observed gamma-ray bursts (GRBs) are produced at
cosmological distances and that the GRB production rate may follow the star
formation rate. We model the BATSE-detected intensity distribution of long GRBs
in order to determine their space density distribution and opening angle
distribution. Our main results are: the lower and upper distance limits to the
GRB production are z 0.24 and >10, respectively; the GRB opening angle follows
an exponential distribution and the mean opening angle is about 0.03 radians;
and the peak luminosity appears to be a better standard candle than the total
energy of a GRB.


title: Is there Supernova Evidence for Dark Energy Metamorphosis ?

abstract:
  We reconstruct the equation of state $w(z)$ of dark energy (DE) using a
recently released data set containing 172 type Ia supernovae without assuming
the prior $w(z) \geq -1$ (in contrast to previous studies). We find that dark
energy evolves rapidly and metamorphoses from dust-like behaviour at high $z$
($w \simeq 0$ at $z \sim 1$) to a strongly negative equation of state at
present ($w \lleq -1$ at $z \simeq 0$). Dark energy metamorphosis appears to be
a robust phenomenon which manifests for a large variety of SNe data samples
provided one does not invoke the weak energy prior $\rho + p \geq 0$. Invoking
this prior considerably weakens the rate of growth of $w(z)$. These results
demonstrate that dark energy with an evolving equation of state provides a
compelling alternative to a cosmological constant if data are analysed in a
prior-free manner and the weak energy condition is not imposed by hand.


title:
On the Power-Law Tail in the Mass Function of Protostellar Condensations
  and Stars

abstract:
  We explore the idea that the power-law tail in the mass function of
protostellar condensations and stars arises from the accretion of ambient cloud
material on to a condensation, coupled with a nonuniform (exponential)
distribution of accretion lifetimes. This model allows for the generation of
power-law distributions in all star-forming regions, even if condensations
start with a lognormal mass distribution, as may be expected from the central
limit theorem, and supported by some recent numerical simulations of turbulent
molecular clouds. For a condensation mass $m$ with growth rate $dm/dt \propto
m$, an analytic three-parameter probability density function is derived; it
resembles a lognormal at low mass and has a pure power-law high-mass tail. An
approximate power-law tail is also expected for other growth laws, and we
calculate the distribution for the plausible case $dm/dt \propto m^{2/3}$.
Furthermore, any single time snapshot of the masses of condensations that are
still accreting (and are of varying ages) also yields a distribution with a
power-law tail similar to that of the IMF.


title:
Implications for unified schemes from the quasar fraction and
  emission-line luminosities in radio-selected samples

abstract:
  We use a principal components analysis of radio-selected (3CRR, 6CE and 7CRS)
AGN datasets to define two parameters related to low-frequency (151 MHz) radio
luminosity L_151 and [OIII] luminosity L_[OIII]: a parameter alpha encoding the
L_151 - L_[OIII] correlation and a parameter beta encoding scatter about this
correlation. We describe methods for constructing generalized luminosity
functions (GLFs) based on alpha, beta, redshift and schemes for unifying
quasars and radio galaxies.
  Luminosity-dependent unified schemes (e.g. a receding-torus scheme) have been
invoked to explain the low quasar to radio galaxy fraction at low alpha and the
differences in emission-line luminosities of radio quasars and radio galaxies.
With the constraints of the 3CRR, 6CE and 7CRS datasets and radio source
counts, our GLF approach was used to determine whether a receding-torus-like
scheme is required if there are two populations of radio sources: one at low
alpha, consisting of 'starved AGN'; the other at high alpha consisting of
'Eddington-tuned AGN'. Because of the overlap between these two populations and
the effects of the beta parameter, schemes with or without a receding torus can
produce a low quasar fraction at low alpha and differences in [OIII] luminosity
between radio galaxies and quasars. The receding torus may be a physical
process important in one or more populations of radio sources, but this is not
yet proved either by the quasar fraction or the emission-line properties of
radio-selected samples.


title:
Coronal versus photospheric abundances of stars with different activity
  levels

abstract:
  We report a detailed analysis of the coronal abundance of 4 stars with
varying levels of activity and with accurately known photospheric abundances.
The coronal abundance is determined here using a line flux analysis and a full
determination of the differential emission measure. Photospheric abundance
values are taken from literature works. Previous coronal abundance
determinations have generally been compared to solar photospheric abundances;
from this a number of general properties have been inferred, such as the
presence of a coronal metal depletion with an inverse First Ionization
Potential correlated with activity level. Here we show that, when coronal
abundances are compared with real photospheric values for the individual stars,
the resulting pattern can be very different. Also, we present evidence that, in
some cases, the coronal metal abundance may not be uniform in the corona; in
particular it can vary with the temperature of the emitting plasma.


title:
Can the Bump be Observed in the Early Afterglow of GRBS with X-Ray Line
  Emission Features?

abstract:
  Extremely powerful emission lines are observed in the X-ray afterglow of
several GRBs. The energy contained in the illuminating continuum which is
responsible for the line production exceeds 10$^{51}$ erg, much higher than
that of the collimated GRBs. It constrains the models which explain the
production of X-ray emission lines. In this paper, We argue that this energy
can come from a continuous postburst outflow. Focusing on a central engine of
highly magnetized millisecond pulsar or magnetar we find that afterglow can be
affected by the illuminating continuum, and therefore a distinct achromatic
bump may be observed in the early afterglow lightcurves. With the luminosity of
the continuous outflow which produces the line emission, we define the upper
limit of the time when the bump feature appears. We argue that the reason why
the achromatic bumps have not been detected so far is that the bumps should
appear at the time too early to be observed.


title: Cosmic Ray Scattering by Compressible Magnetohydrodynamic Turbulence

abstract:
  Recent advances in understanding of magnetohydrodynamic (MHD) turbulence call
for substantial revisions in the picture of cosmic ray transport. In this paper
we use recently obtained scaling laws for MHD modes to calculate the scattering
frequency for cosmic rays in the ISM. We consider gyroresonance with MHD modes
(Alfvenic, slow and fast) and transit-time damping (TTD) by fast modes. We
provide calculations of cosmic ray scattering for various phases of
interstellar medium with realistic interstellar turbulence driving that is
consistent with the velocity dispersions observed in diffuse gas. We account
for the turbulence cutoff arising from both collisional and collisionless
damping. We obtain analytical expressions for diffusion coefficients that enter
Fokker-Planck equation describing cosmic ray evolution. We calculate the
scattering rate and parallel spatial diffusion coefficients of cosmic rays for
both Alfvenic and fast modes. We conclude that fast modes provides the dominant
contribution to cosmic ray scattering for the typical interstellar conditions
in spite of the fact that fast modes are subjected to damping. We show that the
efficiency of the scattering depends on the plasma beta since it determines the
damping of the fast modes. We also show that the streaming instability is
modified in the presence of turbulence.


title:
Translational Velocities and Rotational Rates of Interstellar Dust
  Grains

abstract:
  Interstellar dust grains exhibit complex dynamics which is essential for
understanding many key interstellar processes that involve dust, including
grain alignment, grain growth, grain shattering etc. Grain rotational and
translational motions are affected not only by gaseous collisions, but also by
interactions with ions, photons, magnetic fields etc. Some of those
interactions, e.g. interactions of ions with the dipole electric moment of dust
grains, require the quantum nature of the process to be accounted for.
Similarly, coupling of rotational and vibrational degrees of freedom in a grain
happens due to relaxation processes, among which the process related to nuclear
spins frequently is the dominant one. This coupling modifies substantially both
the dynamics of rotational and translational motions by inducing grain flips.
The flipping averages our certain systematic torques and forces that act on
grains. As the rate of flipping is larger for smaller grains, these grains can
be ``thermally trapped'', i.e. rotate at a thermal rate in spite of the
presence of systematic torques. Moreover, a subset of small grains with high
dipole moments may rotate at subthermal rates due to high damping arising from
grain emission in microwave range of frequencies. Translational dynamics of
grains is mostly dominated by grain interactions with magnetohydrodynamic
turbulence. Efficient turbulent mixing of dust grains limits the degree to
which grains of different sizes may be segregated in space.


title: Grain Alignment in Molecular Clouds

abstract:
  One of the most informative techniques of studying magnetic fields in
molecular clouds is based on the use of starlight polarization and polarized
emission arising from aligned dust. How reliable the interpretation of the
polarization maps in terms of magnetic fields is the issue that the grain
alignment theory addresses.
  I briefly review basic physical processes involved in grain alignment.


title:
Basic Properties of Compressible MHD Turbulence: Implications for
  Molecular Clouds

abstract:
  Recent advances in understanding of the basic properties of compressible
Magnetohydrodynamic (MHD) turbulence call for revisions of some of the
generally accepted concepts. First, MHD turbulence is not so messy as it is
usually believed. In fact, the notion of strong non-linear coupling of
compressible and incompressible motions is not tenable. Alfven, slow and fast
modes of MHD turbulence follow their own cascades and exhibit degrees of
anisotropy consistent with theoretical expectations. Second, the fast decay of
turbulence is not related to the compressibility of fluid. Rates of decay of
compressible and incompressible motions are very similar. Third, viscosity by
neutrals does not suppress MHD turbulence in a partially ionized gas. Instead,
MHD turbulence develops magnetic cascade at scales below the scale at which
neutrals damp ordinary hydrodynamic motions. The implications of those changes
of MHD turbulence paradigm for molecular clouds require further studies. Those
studies can benefit from testing of theoretical predictions using new
statistical techniques that utilize spectroscopic data. We briefly discuss
advances in development of tools using which the statistics of turbulent
velocity can be recovered from observations.


title: Testing the CMB Data for Systematic Effects

abstract:
  Under the assumption that the concordance Lambda-cold dark matter (CDM) model
is the correct model, we test the cosmic microwave background (CMB) anisotropy
data for systematic effects by examining the band pass temperature residuals
with respect to this model. Residuals are analysed as a function of angular
scale l, galactic latitude, frequency, calibration source, instrument type and
several other variables that may be associated with potential systematic
effects. Our main result is that we find no significant systematic errors
associated with these variables. However, we do find marginal evidence for a
trend associated with galactic latitude indicative of galactic contamination.


title:
Selecting Very Soft X-Ray Sources in External Galaxies: Luminous
  Supersoft X-ray Sources and Quasisoft Sources

abstract:
  We introduce a procedure to identify very soft X-ray sources (VSSs) in
external galaxies. Our immediate goal was to formulate a systematic procedure
to identify luminous supersoft X-ray sources (SSSs), so as to allow comparisons
among galaxies and to study environmental effects. The focus of this paper is
on the design of the selection algorithm and on its application to simulated
data. In the companion paper we test it by applying it to sources discovered
through Chandra observations of 4 galaxies. We find that, in its application to
both simulated and real data, our procedure also selects somewhat harder
sources, which we call quasisoft. Whereas values of kT for SSSs are typically
tens of eV, some quasisoft sources (QSSs) may have kT as high as ~250-300 eV.
The dominant spectral component of other QSSs may be as soft as SSS spectra,
but the spectra may also include a low-luminosity harder component. We sketch
physical models for both supersoft and quasisoft sources. Some SSSs are likely
to be accreting white dwarfs; some of these may be progenitors of Type Ia
supernovae. Most QSSs may be too hot to be white dwarfs. They, together with a
subset of SSSs, may be neutron stars or, perhaps most likely, accreting
intermediate-mass black holes.


title: The Discovery of Quasisoft and Supersoft Sources in External Galaxies

abstract:
  We apply a uniform procedure to select very soft sources from point sources
observed by Chandra in 4 galaxies. This sample includes one elliptical galaxy
(NGC 4967), 2 face-on spirals (M101 and M83), and an interacting galaxy (M51).
We have found very soft X-ray sources (VSSs) in every galaxy. Some of these fit
the criteria for canonical supersoft sources (SSSs), while others are somewhat
harder. These latter have characteristic values of kT < 300 eV; we refer to
them as quasisoft sources (QSSs). We found a combined total of 149 VSSs in the
4 galaxies we considered; 77 were SSSs and 72 were QSSs. (See the paper for the
original long abstract)


title: Collapse of Magnetized Singular Isothermal Toroids: I. Non-Rotating Case

abstract:
  We study numerically the collapse of non-rotating, self-gravitating,
magnetized, singular isothermal toroids characterized by sound speed, $a$, and
level of magnetic to thermal support, $H_0$. In qualitative agreement with
previous treatments by Galli & Shu and other workers, we find that the
infalling material is deflected by the field lines towards the equatorial
plane, creating a high-density, flattened structure -- a pseudodisk. The
pseudodisk contracts dynamically in the radial direction, dragging the field
lines threading it into a highly pinched configuration that resembles a split
monopole. The oppositely directed field lines across the midplane and the large
implied stresses may play a role in how magnetic flux is lost in the actual
situation in the presence of finite resistivity or ambipolar diffusion. The
infall rate into the central regions is given to 5% uncertainty by the formula,
$\dot M = (1+H_0)a^3/G$, where $G$ is the universal gravitational constant,
anticipated by semi-analytical studies of the self-similar gravitational
collapses of the singular isothermal sphere and isopedically magnetized disks.
The introduction of finite initial rotation results in a complex interplay
between pseudodisk and true (Keplerian) disk formation that is examined in a
companion paper.


title:
Collapse of Magnetized Singular Isothermal Toroids: II. Rotation and
  Magnetic Braking

abstract:
  We study numerically the collapse of rotating, magnetized molecular cloud
cores, focusing on rotation and magnetic braking during the main accretion
phase of isolated star formation. Motivated by previous numerical work and
analytic considerations, we idealize the pre-collapse core as a magnetized
singular isothermal toroid, with a constant rotational speed everywhere. The
collapse starts from the center, and propagates outwards in an inside-out
fashion, satisfying exact self-similarity in space and time. For rotation rates
and field strengths typical of dense low-mass cores, the main feature remains
the flattening of the mass distribution along field lines -- the formation of a
pseudodisk, as in the nonrotating cases. The density distribution of the
pseudodisk is little affected by rotation. On the other hand, the rotation rate
is strongly modified by pseudodisk formation. Most of the centrally accreted
material reaches the vicinity of the protostar through the pseudodisk. The
specific angular momentum can be greatly reduced on the way, by an order of
magnitude or more, even when the pre-collapse field strength is substantially
below the critical value for dominant cloud support. The efficient magnetic
braking is due to the pinched geometry of the magnetic field in the pseudodisk,
which strengthens the magnetic field and lengthens the level arm for braking.
Both effects enhance the magnetic transport of angular momentum from inside to
outside. The excess angular momentum is carried away in a low-speed outflow
that has, despite claims made by other workers, little in common with observed
bipolar molecular outflows. We discuss the implications of our calculations for
the formation of true disks that are supported against gravity by rotation.


title: Power Spectra in Spacetime Noncommutative Inflation

abstract:
  String/M theory inspires an uncertainty relation between space and time which
deviates from general relativity. It is possible to explore this deviation from
cosmological observations, in particular from the CMB fluctuation spectrum.
This paper extends some previous observations to more general inflation
schemes, we find that the noncommutative spacetime effects always suppress the
power spectrum, of both the scalar and tensor perturbations, and may provide a
large enough running of the spectral index to fit the WMAP data in the
inflation model.


title:
Galaxy ecology: groups and low-density environments in the SDSS and
  2dFGRS

abstract:
  We analyse the observed correlation between galaxy environment and H-alpha
emission line strength, using volume-limited samples and group catalogues of
24968 galaxies drawn from the 2dF Galaxy Redshift Survey (Mb<-19.5) and the
Sloan Digital Sky Survey (Mr<-20.6). We characterise the environment by 1)
Sigma_5, the surface number density of galaxies determined by the projected
distance to the 5th nearest neighbour; and 2) rho1.1 and rho5.5,
three-dimensional density estimates obtained by convolving the galaxy
distribution with Gaussian kernels of dispersion 1.1 Mpc and 5.5 Mpc,
respectively. We find that star-forming and quiescent galaxies form two
distinct populations, as characterised by their H-alpha equivalent width,
EW(Ha). The relative numbers of star-forming and quiescent galaxies varies
strongly and continuously with local density. However, the distribution of
EW(Ha) amongst the star-forming population is independent of environment. The
fraction of star-forming galaxies shows strong sensitivity to the density on
large scales, rho5.5, which is likely independent of the trend with local
density, rho1.1. We use two differently-selected group catalogues to
demonstrate that the correlation with galaxy density is approximately
independent of group velocity dispersion, for sigma=200-1000 km/s. Even in the
lowest density environments, no more than ~70 per cent of galaxies show
significant H-alpha emission. Based on these results, we conclude that the
present-day correlation between star formation rate and environment is a result
of short-timescale mechanisms that take place preferentially at high redshift,
such as starbursts induced by galaxy-galaxy interactions.


title: Q-LET - Quick Lensing Estimation Tool - An application to SN2003es

abstract:
  Q-LET is a FORTRAN 77 code that enables a quick estimate of the gravitational
lensing effects on a point- or an extended source. The user provided input
consists of the redshifts, angular positions relative to the source, mass or
velocity dispersion estimate and halo type for the lens galaxies. The
considered halo types are the Navarro-Frenk-White and the Singular Isothermal
Sphere. The code uses the so-called multiple lens-plane method to find the
magnification and intrinsic shape of the source. This method takes into account
the multiple deflections that may arise when several mass accumulations are
situated at different redshifts close to the line-of-sight.
  The Q-LET code is applied to the recently discovered supernova, SN2003es,
which is likely to be of Type Ia as its host galaxy is classified as an
elliptical. We find that SN2003es is likely to have been significantly
magnified by gravitational lensing and that this should be considered in high-z
studies if this SN is to be used to determine the cosmological parameters.
  Q-LET was motivated by the supernova searches, where lensing can be a
problem, but it can also be applied to any simple lens system where a quick
estimate is wanted, e.g. the single lens case.


title:
The XMM--NEWTON Omega Project: II.Cosmological implications from the
  high redshift L-T relation of X-ray clusters

abstract:
  The evolution with redshift of the temperature-luminosity relation of X-ray
galaxy clusters is a key ingredient to break degeneracies in the interpretation
of X-ray clusters redshift number counts. We therefore take advantage of the
recent measurements of the temperature-luminosity relation of distant clusters
observed with XMM-Newton and Chandra satellites to examine theoretical number
counts expected for different available X-rays cluster samples, namely the
RDCS, EMSS, SHARC, 160deg^2 and the MACS at redshift greater than 0.3. We
derive these counts without any adjustment, using models previously normalized
to the local temperature distribution function and to the high-z (z = 0.33)
TDF. We find that these models having Omega_M in the range [0.85-1.] predict
counts in remarkable agreement with the observed counts in the different
samples. We illustrate that this conclusion is weakly sensitive to the various
ingredients of the modeling. Therefore number counts provide a robust evidence
of an evolving population. A realistic flat low density model (Omega_M = 0.3),
normalized to the local abundance of clusters is found to overproduce cluster
abundance at high redshift (above z = 0.5) by nearly an order of magnitude.
This result is in conflict with the popular concordance model. The conflict
could indicate a deviation from the expected scaling of the M-T relation with
redshift.


title: Six Years of ScoX-1 Monitoring with BeppoSAX Wide Field Cameras

abstract:
  We performed a systematic analysis of 54 Wide Field Camera (WFC) observations
of ScoX-1 available in the BeppoSAX public archive. Observations span over the
six years of BeppoSAX mission lifetime and include 690 hr of data. We searched
for shifts and shape changes of the Z pattern in the color-color diagrams. We
find that the Z pattern occupies most of the time the same locus in the
color-color diagram. There are however a few exceptions, which are discussed in
detail.


title:
The Tilt of the Fundamental Plane: Three-quarters Structural
  Nonhomology, One-quarter Stellar Population

abstract:
  The variation of the mass-to-light ratios M/L of early type galaxies as
function of their luminosities L is investigated. It is shown that the tilt
beta=0.27 (in the B--band) of the fundamental plane relation M/L ~ L^{beta} can
be understood as a combination of two effects: about one-quarter (i.e. dbeta
=0.07) is a result of systematic variations of the stellar population
properties with increasing luminosity. The remaining three-quarters (i.e. dbeta
=0.2) can be completely attributed to nonhomology effects that lead to a
systematic change of the surface brightness profiles with increasing
luminosity. Consequently, the observed tilt in the K-band (beta=0.17) where
stellar population effects are negligible, is explained by nonhomology effects
alone. After correcting for nonhomology, the mean value of the mass-to-light
ratio of elliptical galaxies (M/L_B) is 7.1+-2.8 (1 sigma scatter).


title: The CLASS blazar survey: testing the blazar sequence

abstract:
  We discuss the properties of the sources in the CLASS Blazar survey which
aims at the selection of low radio power (P(5GHz)<10^25 W Hz^-1) blazars. We
use VLA data from available catalogues and from our own observations to
constrain the radio core-dominance of the sample which, together with the flat
radio spectral index, is a signature of the blazar activity. X-ray data from
the ROSAT All Sky Survey were also collected in order to constrain the
radio-to-X-ray luminosity ratio (alpha_RX) of the sources. The data analysis
shows that more than 30% of sources at low radio power (P(5 GHz)<10^25 W Hz^-1)
have an alpha_RX steeper than that expected in the framework of the ``blazar
sequence'' recently put forward to unify the high and low power blazars. The
possibility that this result is influenced by contaminating sources in the
current sample is discussed. The conclusion is that, even if a number of
non-blazars (typically CSO/GPS sources) are expected in the survey, it is
unlikely that this constitutes the sole reason for the observed deviation. In
particular, we show 2 examples for which the blazar nature is confirmed from
VLBI data and for which the steep alpha_RX (suggesting a synchrotron peak
frequency below 10^15.5 Hz) and the low radio power (0.6-2x10^24 W Hz^-1) put
these sources outside the ``blazar sequence''. The results presented here show
the importance of a correct and unbiased sampling of the low-power regime of
the blazar population.


title: Magnetic Fields in Galaxy Clusters

abstract:
  Magnetic fields in galaxy clusters can be investigated using a variety of
techniques. Recent studies including radio halos, Inverse Compton hard X-ray
emissions and Faraday rotation measure, are briefly outlined. A numerical
approach for investigating cluster magnetic fields strength and structure is
presented. It consists of producing simulated rotation measure, radio halo
images, and radio halo polarization, obtained from 3-dimensional multi-scale
cluster magnetic field models, and comparing with observations.


title:
Peering Through the Muck: Notes on the Influence of the Galactic
  Interstellar Medium on Extragalactic Observations

abstract:
  This paper considers some effects of foreground Galactic gas on radiation
received from extragalactic objects, with an emphasis on the use of the 21cm
line to determine the total N(HI). In general, the opacity of the 21cm line
makes it impossible to derive an accurate value of N(HI) by simply applying a
formula to the observed emission, except in directions where there is very
little interstellar matter. The 21cm line can be used to estimate the
likelihood that there is significant molecular hydrogen in a particular
direction, but carries little or no information on the amount of ionized gas,
which can be a major source of foreground effects. Considerable discussion is
devoted to the importance of small-scale angular structure in HI, with the
conclusion that it will rarely contribute significantly to the total error
compared to other factors (such as the effects of ionized gas) for
extragalactic sight lines at high Galactic latitude. The direction of the
Hubble/Chandra Deep Field North is used as an example of the complexities that
might occur even in the absence of opacity or molecular gas.


title:
Axisymmetric dynamical models for SAURON and OASIS observations of NGC
  3377

abstract:
  We present a unique set of nested stellar kinematical maps of NGC 3377
obtained with the integral-field spectrographs OASIS and SAURON. We then
construct general axisymmetric dynamical models for this galaxy, based on the
Schwarzschild numerical orbit superposition technique applied to these
complementary measurements. We show how these two datasets constrain the mass
of the central massive object and the overall mass-to-light ratio of the galaxy
by probing the inner and outer regions respectively. The simultaneous use of
both datasets leads us to confirm the presence of a massive black hole with a
mass of $M_{BH} = 7_{-5}^{+4} 10^{7} M_\sun$ (99.7% confidence level), with a
best-fit stellar mass-to-light ratio $\Upsilon_I = 2.1 \pm 0.2$ (for an assumed
edge-on inclination).


title: An evolutionary model for pulsar-driven supernova remnants

abstract:
  We present a model of a pulsar wind nebula evolving inside its associated
supernova remnant. The model uses a hydrodynamics code to simulate the
evolution of this system when the pulsar has a high velocity. The simulation
distinguishes four different stages of pulsar wind nebula evolution: the
supersonic expansion stage, the reverse shock interaction stage, the subsonic
expansion stage and ultimately the bow shock stage. The simulation bears out
that, due to the high velocity of the pulsar, the position of the pulsar is
off-centered with respect to its pulsar wind nebula, after the passage of the
reverse shock. Subsequently the pulsar wind nebula expands subsonically untill
the event of the bow shock formation, when the motion of the pulsar becomes
supersonic. The bow shock formation event occurs at roughly half the crossing
time, when the pulsar is positioned at 0.677 times the radius of the supernova
remnant blastwave, in complete agreement with analytical predictions. The
crossing time is defined by the age of the supernova remnant, when the pulsar
overtakes the blastwave bounding the supernova remnant.
  The results of the model are applied to three supernova remnants: N157B,
G327.1-1.1 and W44. We argue that the head of the pulsar wind nebula,
containing the active pulsar, inside the first two systems are not bounded by a
bow shock. However, in the case of W44 we argue for a scenario in which the
pulsar wind nebula is bounded by a bow shock, due to the supersonic motion of
the pulsar.


title:
Limits on Very High Energy Emission from Gamma-Ray Bursts with the
  Milagro Observatory

abstract:
  The Milagro telescope monitors the northern sky for 100 GeV to 100 TeV
transient emission through continuous very high energy wide-field observations.
The large effective area and ~100 GeV energy threshold of Milagro allow it to
detect very high energy (VHE) gamma-ray burst emission with much higher
sensitivity than previous instruments and a fluence sensitivity at VHE energies
comparable to that of dedicated gamma-ray burst satellites at keV to MeV
energies. Even in the absence of a positive detection, VHE observations can
place important constraints on gamma-ray burst (GRB) progenitor and emission
models. We present limits on the VHE flux of 40 s -- 3 h duration transients
nearby to earth, as well as sensitivity distributions which have been corrected
for gamma-ray absorption by extragalactic background light and cosmological
effects. The sensitivity distributions suggest that the typical intrinsic VHE
fluence of GRBs is similar or weaker than the keV -- MeV emission, and we
demonstrate how these sensitivity distributions may be used to place
observational constraints on the absolute VHE luminosity of gamma-ray bursts
for any GRB emission and progenitor model.


title:
X-ray Reflection from Inhomogeneous Accretion Disks: I. Toy Models and
  Photon Bubbles

abstract:
  Numerical simulations of the interiors of radiation dominated accretion disks
show that significant density inhomogeneities can be generated in the gas.
Here, we present the first results of our study on X-ray reflection spectra
from such heterogeneous density structures. We consider two cases: first, we
produce a number of toy models where a sharp increase or decrease in density of
variable width is placed at different depths in a uniform slab. Comparing the
resulting reflection spectra to those from an unaltered slab shows that the
inhomogeneity can affect the emission features, in particular the Fe K and O
VIII Lyalpha lines. The magnitude of any differences depends on both the
parameters of the density change and the ionizing power of the illuminating
radiation, but the inhomogeneity is required to be within ~2 Thomson depths of
the surface to cause an effect. However, only relatively small variations in
density (on the order of a few) are necessary for significant changes in the
reflection features to be possible. Our second test was to compute reflection
spectra from the density structure predicted by a simulation of the non-linear
outcome of the photon bubble instability. The resulting spectra also exhibited
differences from the constant density models, caused primarily by a strong 6.7
keV iron line. Nevertheless, constant density models can provide a good fit to
simulated spectra, albeit with a low reflection fraction, between 2 and 10 keV.
Below 2 keV, differences in the predicted soft X-ray line emission result in
very poor fits with a constant density ionized disk model. The results indicate
that density inhomogeneities may further complicate the relationship between
the Fe K equivalent width and the X-ray continuum.


title: 3D AMR Simulations of Point-Symmetric Nebulae

abstract:
  At the end of their lives low mass stars such as our Sun lose most of their
mass. The resulting planetary nebulae show a wide variety of shapes, from
spherical to highly bipolar. According to the generalized interacting stellar
winds model, these shapes are due to an interaction between a very fast tenuous
outflow, and a denser environment left over from an earlier slow phase of mass
loss. Previous analytical and numerical work shows that this mechanism can
explain cylindrically symmetric nebulae very well. However, many circumstellar
nebulae have a multipolar or point-symmetric shape. With two-dimensional
calculations, Icke showed that these seemingly enigmatic forms can be easily
reproduced by a two-wind model in which the confining disk is warped, as is
expected to occur in irradiated disks. Here, we present the extension to fully
three-dimensional adaptive mesh refinement simulations of such an interaction.


title:
Three-Dimensional Adaptive Mesh Refinement Simulations of
  Point-Symmetric Nebulae

abstract:
  Previous analytical and numerical work shows that the generalized interacting
stellar winds model can explain the observed bipolar shapes of planetary
nebulae very well. However, many circumstellar nebulae have a multipolar or
point-symmetric shape. With two-dimensional calculations, Icke showed that
these seemingly enigmatic forms can be easily reproduced by a two-wind model in
which the confining disk is warped, as is expected to occur in irradiated
disks. In this contribution we present the extension to fully three-dimensional
adaptive mesh refinement simulations of such an interaction.


title:
Periodic Optical Outbursts from the Be/Neutron Star Binary AX
  J0049.4-7323

abstract:
  The optical light curve of the Be/neutron star binary AX J0049.4-7323 has
been investigated using data from the MACHO and OGLE-II projects. This X-ray
source, whose neutron star has a very slow rotation rate (P_pulse=755.5 sec),
shows optical outbursts every 394 days. The regularity of these outbursts
suggests that their recurrence time is the orbital period of the system. During
the outbursts the system brightens and becomes slightly redder. A possible
interpretation is that a portion of the equatorial disk is excited as the
neutron star passes through it during periastron passage. In the intervals
between outbursts the light curve shows 11-day quasi-periodic varability which
may be associated with the rotation of the Be star's extended disk.


title: Does the interstellar magnetic field follow the Chandrasekhar-Fermi law?

abstract:
  We carried out 1.25 pc resolution MHD simulations of the ISM -- including the
large scale galactic fountain -- by fully tracking the time-dependent evolution
of the magnetic field and the formation of shock compressed regions in a
supernova-driven ISM. The simulations show that large scale gas streams emerge,
driven by SN explosions, which are responsible for the formation and
destruction of shocked compressed layers with lifetimes up to some 15 Myr. The
T\leq 10^{3} K gas is distributed in filaments which tend to show a preferred
orientation due to the anisotropy of the flow induced by the galactic magnetic
field. The simulations also show that the magnetic field has a high
variability, it is largely uncorrelated with the density and it is driven by
inertial motions. The latter is consistent with the fact that ram pressure
dominates the flow for 10^{2}<T\leq 10^{6} K. For T> 10^{6} K thermal pressure
dominates, while for T\leq 10^{2} K (stable branch) magnetic pressure takes
over.


title:
A Revised Ephemeris and FUSE Observations of the Supersoft X-ray Source
  CAL 83

abstract:
  A new ephemeris has been determined for the supersoft X-ray binary CAL 83
using MACHO photometry. With an improved orbital period of 1.047568 days, it is
now possible to phase together photometric and spectroscopic data obtained over
the past two decades with new far ultraviolet spectra taken with FUSE. We
discuss the properties of the orbital and longterm optical light curves as well
as the colors of CAL 83. In the far ultraviolet the only well-detected stellar
feature is emission from the O VI resonance doublet. The radial velocity of
this emission appears to differ from that of HeII in the optical region,
although we only have partial phase coverage for the O VI line. The FUSE
continuum variations are similar to the optical light curve in phase and
amplitude.


title: Maps of the millimetre sky from the BOOMERanG experiment

abstract:
  In the 1998-99 flight, BOOMERanG has produced maps of $\sim 4 %$ of the sky
at high Galactic latitudes, at frequencies of 90, 150, 240 and 410 GHz, with
resolution $\simgt 10'$. The faint structure of the Cosmic Microwave Background
at horizon and sub-horizon scales is evident in these maps. These maps compare
well to the maps recently obtained at lower frequencies by the WMAP experiment.
Here we compare the amplitude and morphology of the structures observed in the
two sets of maps. We also outline the polarization sensitive version of
BOOMERanG, which was flown early this year to measure the linear polarization
of the microwave sky at 150, 240 and 350 GHz.


title: Constraints on the Very High Energy Emission from BL Lacertae Objects

abstract:
  We present results from observations of 29 BL Lacertae objects, taken with
the Whipple Observatory 10 m Gamma-Ray Telescope between 1995 and 2000. The
observed objects are mostly at low redshift (z < 0.2) but observations of
objects of z up to 0.444 are also reported. Five of the objects are EGRET
sources and two are unconfirmed TeV sources. Three of the confirmed sources of
extragalactic TeV gamma rays were originally observed as part of this survey
and have been reported elsewhere. No significant excesses are detected from any
of the other objects observed, on time scales of days, months or years. We
report 99.9% confidence level flux upper limits for the objects for each
observing season. The flux upper limits are typically 20% of the Crab flux
although, for some sources, limits as sensitive as 6% of the Crab flux were
derived. The results are consistent with the synchrotron-self-Compton (SSC)
model predictions considered in this work.


title: Unstable Nonradial Oscillations on Helium Burning Neutron Stars

abstract:
  Material accreted onto a neutron star can stably burn in steady state only
when the accretion rate is high (typically super-Eddington) or if a large flux
from the neutron star crust permeates the outer atmosphere. For such situations
we have analyzed the stability of nonradial oscillations, finding one unstable
mode for pure helium accretion. This is a shallow surface wave which resides in
the helium atmosphere above the heavier ashes of the ocean. It is excited by
the increase in the nuclear reaction rate during the oscillations, and it grows
on the timescale of a second. For a slowly rotating star, this mode has a
frequency of approximately 20-30 Hz (for l=1), and we calculate the full
spectrum that a rapidly rotating (>>30 Hz) neutron star would support. The
short period X-ray binary 4U 1820--30 is accreting helium rich material and is
the system most likely to show this unstable mode,especially when it is not
exhibiting X-ray bursts. Our discovery of an unstable mode in a thermally
stable atmosphere shows that nonradial perturbations have a different stability
criterion than the spherically symmetric thermal perturbations that generate
type I X-ray bursts.


title:
The Rapidly Rotating, Hydrogen Deficient, Hot Post-Asymptotic Giant
  Branch Star ZNG 1 in the Globular Cluster M5

abstract:
  We report observations of the hot post-asymptotic giant branch star ZNG 1 in
the globular cluster M5 (NGC 5904) with the Far Ultraviolet Spectroscopic
Explorer (FUSE). From the resulting spectrum, we derive an effective
temperature T_eff = 44300 +/- 300 K, a surface gravity log g = 4.3 +/- 0.1, a
rotational velocity v sin i = 170 +/- 20 km/s, and a luminosity log (L/L_sun) =
3.52 +/- 0.04. The atmosphere is helium-rich (Y = 0.93), with enhanced carbon
(2.6% by mass), nitrogen (0.51%) and oxygen (0.37%) abundances. The spectrum
shows evidence for a wind with terminal velocity near 1000 km/s and an
expanding shell of carbon- and nitrogen-rich material around the star. The
abundance pattern of ZNG 1 is suggestive of the ``born-again'' scenario,
whereby a star on the white-dwarf cooling curve undergoes a very late shell
flash and returns to the AGB, but the star's rapid rotation is more easily
explained by a previous interaction with a binary companion.


title:
Wave damping by MHD turbulence and its effect upon cosmic ray
  propagation in the ISM

abstract:
  Cosmic rays scatter off magnetic irregularities (Alfven waves) with which
they are resonant, that is waves of wavelength comparable to their gyroradii.
These waves may be generated either by the cosmic rays themselves, if they
stream faster than the Alfven speed, or by sources of MHD turbulence. Waves
excited by streaming cosmic rays are ideally shaped for scattering, whereas the
scattering efficiency of MHD turbulence is severely diminished by its
anisotropy. We show that MHD turbulence has an indirect effect on cosmic ray
propagation by acting as a damping mechanism for cosmic ray generated waves.
The hot (``coronal'') phase of the interstellar medium is the best candidate
location for cosmic ray confinement by scattering from self-generated waves. We
relate the streaming velocity of cosmic rays to the rate of turbulent
dissipation in this medium, for the case in which turbulent damping is the
dominant damping mechanism. We conclude that cosmic rays with up to 10^2 GeV
could not stream much faster than the Alfven speed, but that 10^6 GeV cosmic
rays would stream unimpeded by self-generated waves unless the coronal gas were
remarkably turbulence-free.


title:
Dramatic X-ray Spectral Variability of the Broad Absorption Line Quasar
  PG2112+059

abstract:
  With a 1999 ASCA observation, PG2112+059 became notable as the first Broad
Absorption Line (BAL) quasar found to exhibit a typical radio-quiet quasar
X-ray continuum underlying a large amount of intrinsic absorption. We present a
recent Chandra ACIS-S3 observation of PG2112+059 that demonstrates remarkable
spectral and luminosity variability since that time. In addition to a decrease
in the continuum normalization by a factor of ~3.5, the absorption column
density has apparently increased substantially, and a strong feature in the Fe
K alpha region has appeared. Concurrent HST STIS data compared with archival
HST data from earlier epochs show evidence for variability of the continuum (up
to a factor of ~1.7 in the ultraviolet), and in some absorption features of the
CIV 1549 BAL since 1992; however, the OVI BAL structure is consistent with a
1995 observation. We also present evidence for Ly beta--OVI 1037.62 and Ly
alpha--NV 1242.80 line-locked absorption systems, supporting the assumption
that ultraviolet line pressure is driving the BAL outflow. Whereas ultraviolet
BALs typically exhibit only modest equivalent-width variability over timescales
of years, the dramatic X-ray variability of PG2112+059 suggests that X-ray
spectral variability studies of BAL quasars have great potential for probing
the physics of quasar winds.


title:
A Chandra Study of the Effects of a Major Merger on the Structure of
  Abell 2319

abstract:
  We present an analysis of a Chandra observation of the massive, nearby galaxy
cluster Abell 2319. A sharp surface brightness discontinuity--suggested by
previous, lower angular resolution X-ray imaging--is clearly visible in the
ACIS image. This roughly 300kpc feature suggests that a major merger is taking
place with a significant velocity component perpendicular to the line of sight.
The cluster emission-weighted mean temperature is 11.8+/-0.6kev, somewhat
higher than previous temperature measurements. The Chandra temperature map of
A2319 reveals substructure resembling that anticipated based on hydrodynamic
simulations of cluster mergers. The merger feature shows a pressure change
across the surface brightness discontinuity by a factor of <=2.5. The higher
density side of the front has a lower temperature, suggesting the presence of a
cold front similar to those in many other merging clusters. The velocity of the
front is roughly sonic.
  We compare bulk properties of the ICM and galaxies in A2319 to the same
properties in a large sample of clusters as a way of gauging the effects of the
major merger. Interestingly, by comparing A2319 to a sample of 44 clusters
studied with the ROSAT PSPC we find that the X-ray luminosity, isophotal size,
and ICM mass are consistent with the expected values for a cluster of its
temperature; in addition, the K-band galaxy light is consistent with the
light--temperature scaling relation derived from a sample of about 100 clusters
studied with 2MASS. Together, these results indicate either that the merger in
A2319 has not been effective at altering the bulk properties of the cluster, or
that there are large but correlated displacements in these quantities.


title: Mapping the Dark Energy Equation of State

abstract:
  The acceleration of the expansion of the universe has deep implications for
structure formation, the composition of the universe, and its fate. Roughly 70%
of the energy density is in a dark energy, whose nature remains unknown.
Mapping the expansion history through supernovae, mapping the geometry of the
universe and formation of structure through redshift surveys, and mapping the
distance to recombination through the cosmic microwave background provide
complementary, precise probes of the equation of state of the dark energy.
Together these next generation maps of the cosmos can reveal not only the value
today, but the redshift variation, of the equation of state, providing a
critical clue to the underlying physics.


title:
Constraints on QSO models from a relation between the QSO luminosity
  function and the local black hole mass function

abstract:
  QSOs are believed to be powered by accretion onto massive black holes (BHs).
In this paper, assuming that each central BH in nearby galaxies has experienced
the QSO phase and ignoring BH mergers, we establish a relation between the QSO
luminosity function (LF) and the local BH mass function (MF). The QSOLF is
jointly controlled by the luminosity evolution of individual QSOs and the
triggering history of the accretion onto seed BHs. By comparing the time
integral of the QSOLF with that inferred from local BHs, we separate the effect
of the luminosity evolution of individual QSOs from the effect of the
triggering history. Assuming that the nuclear luminosity evolution includes two
phases (first increasing at the Eddington luminosity with growth of BHs and
then declining), we find that observations are generally consistent with the
expected relation between the QSOLF and the local BHMF and obtain the
constraints on QSO models and BH growth. We point out that it is hard to
accurately estimate the value of the QSO lifetime from the QSOLF and/or the
local BHMF, if it is longer than a certain value (e.g., four times of the
Salpeter timescale in this study). We discuss the importance of accurate
measurements of the intrinsic scatter in the BH mass and velocity dispersion
relation of local galaxies and the scatter in the bolometric correction of
QSOs. We also discuss some possible applications of the work in this paper,
such as to the study of the demography of QSOs and the demography of normal
galaxies at intermediate redshift (abridged).


title:
The black hole mass versus velocity dispersion relation in QSOs/Active
  Galactic Nuclei: observational appearance and black hole growth

abstract:
  Studies of massive black holes (BHs) in nearby galactic centers have revealed
a tight correlation between BH mass and galactic velocity dispersion. In this
paper we investigate how the BH mass versus velocity dispersion relation and
the nuclear luminosity versus velocity dispersion relation in QSOs/active
galactic nuclei (AGNs) are connected with the BH mass versus velocity
dispersion relation in local galaxies, through the nuclear luminosity evolution
of individual QSOs/AGNs and the mass growth of individual BHs. In the study we
ignore the effects of BH mergers and assume that the velocity dispersion does
not change significantly during and after the nuclear activity phase. Using the
observed correlation in local galaxies and an assumed form of the QSO/AGN
luminosity evolution and BH growth, we obtain the simulated observational
appearance of the BH mass versus velocity dispersion relation in QSOs/AGNs. The
simulation results illustrate how the BH accretion history (e.g., the lifetime
of nuclear activity and the possibility that QSOs/AGNs accrete at a
super-Eddington accretion rate at the early evolutionary stage) can be inferred
from the difference between the relation in QSOs/AGNs and that in local
galaxies. We also show how the difference may be weakened by the flux limit of
telescopes. We expect that a large complete sample of QSOs/AGNs with accurate
BH mass and velocity dispersion measurements will help to quantitatively
constrain QSO/AGN luminosity evolution and BH growth models.


title: A Review of X-ray Observations of Supernova Remnants

abstract:
  I present a review of X-ray observations of supernova remnants with an
emphasis on shell-type remnants. The topics discussed are the observation of
fresh nucleosynthesis products, shock heating and cosmic ray acceleration.


title: 3D Spectrophotometry of Planetary Nebulae in the Bulge of M31

abstract:
  We introduce crowded field integral field (3D) spectrophotometry as a useful
technique for the study of resolved stellar populations in nearby galaxies. As
a methodological test, we present a pilot study with selected extragalactic
planetary nebulae (XPN) in the bulge of M31, demonstrating how 3D spectroscopy
is able to improve the limited accuracy of background subtraction which one
would normally obtain with classical slit spectroscopy. It is shown that due to
the absence of slit effects, 3D is a most suitable technique for
spectrophometry. We present spectra and line intensities for 5 XPN in M31,
obtained with the MPFS instrument at the Russian 6m BTA, INTEGRAL at the WHT,
and with PMAS at the Calar Alto 3.5m Telescope. Using 3D spectra of bright
standard stars, we demonstrate that the PSF is sampled with high accuracy,
providing a centroiding precision at the milli-arcsec level. Crowded field 3D
spectrophotometry and the use of PSF fitting techniques is suggested as the
method of choice for a number of similar observational problems, including
luminous stars in nearby galaxies, supernovae, QSO host galaxies,
gravitationally lensed QSOs, and others.


title:
Ultra-high-precision velocity measurements of oscillations in alpha Cen
  A

abstract:
  We have made differential radial velocity measurements of the star alpha Cen
A using two spectrographs, UVES and UCLES, both with iodine absorption cells
for wavelength referencing. Stellar oscillations are clearly visible in the
time series. After removing jumps and slow trends in the data, we show that the
precision of the velocity measurements per minute of observing time is 0.42 m/s
for UVES and 1.0 m/s for UCLES, while the noise level in the Fourier spectrum
of the combined data is 1.9 cm/s. As such, these observations represent the
most precise velocities ever measured on any star apart from the Sun.


title: Year-scale morphological variation of the X-ray Crab Nebula

abstract:
  We present year-scale morphological variations of the Crab Nebula revealed by
Chandra X-ray observatory. Observations have been performed about every 1.7
years over the 3 years from its launch. The variations are clearly recognized
at two sites: the torus and the southern jet. The torus, which had been
steadily expanding until 1.7 years ago, now appears to have shrunk in the
latest observation. Additionally, the circular structures seen to the northeast
of the torus have decayed into several arcs. On the other hand, the southern
jet shows the growth of its overall kinked-structure. We discuss the nature of
these variations in terms of the pulsar wind nebula (PWN) mechanism.


title: An X-ray study of the supernova remnant G18.95-1.1

abstract:
  We present an analysis of data from both the Rontgen Satellite (ROSAT), and
the Advanced Satellite for Cosmology and Astrophysics (ASCA) of the supernova
remnant (SNR) G18.95-1.1. We find that the X-ray emission from G18.95-1.1 is
predominantly thermal, heavily absorbed and can be best described by an NEI
(nonequilibrium ionization) model with a temperature around 0.9keV, and an
ionization timescale of 1.1x10^10 /cm3/s. We find only marginal evidence for
non-solar abundances. Comparisons between 21 cm HI absorption data and derived
parameters from our spectral analysis strongly suggest a relatively near-by
remnant (a distance of about 2kpc). Above 4keV, we identify a small region of
emission located at the tip of the central, flat spectrum bar-like feature in
the radio image. We examine two possibilities for this emission region: a
temperature variation within the remnant or a pulsar wind nebula (PWN). The
current data do not allow us to distinguish between these possible
explanations. In the scenario where this high-energy emission region
corresponds to a PWN, our analysis suggests a rotational loss rate for the
unseen pulsar of about 7x10^35 erg/s and a ratio Lr/Lx about 3.6 for the entire
PWN, slightly above the maximum ratio (3.4 for Vela) measured in known PWN.


title:
X-Ray Emission from the Quasar PKS 1127-145: Comptonized IR Photons on
  Parsec Scales

abstract:
  We model the broad-band spectral energy distribution of the innermost
"core-jet" region of the redshift z=1.187 quasar PKS 1127-145. We propose a
scenario where the high energy photons are produced via the Compton scattering
of thermal IR radiation by the relativistic particles in a parsec-scale jet.
The high energy spectrum, together with the observed radio variability and
superluminal expansion, suggest that PKS 1127-145 may be a blazar, despite the
fact that its optical/UV component is likely dominated by thermal radiation
from an accretion disk. The relation of PKS 1127-145 to MeV - blazars is
discussed.


title: Forecasting Cosmic Doomsday from CMB/LSS Cross-Correlations

abstract:
  A broad class of dark energy models, which have been proposed in attempts at
solving the cosmological constant problems, predict a late time variation of
the equation of state with redshift. The variation occurs as a scalar field
picks up speed on its way to negative values of the potential. The negative
potential energy eventually turns the expansion into contraction and the local
universe undergoes a big crunch. In this paper we show that cross-correlations
of the CMB anisotropy and matter distribution, in combination with other
cosmological data, can be used to forecast the imminence of such cosmic
doomsday.