title: The Major Sources of the Cosmic Reionizing Background at z ~ 6

abstract:
  In this paper, we address which sources contributed most of the reionizing
photons. Our argument assumes that the reionization ended around z ~ 6 and that
it was a relatively quick process, i.e., that there was a non-negligible
fraction of neutral hydrogen in the Universe at somewhat earlier epochs.
Starting from our earlier estimate of the luminosity function (LF) of galaxies
at z ~ 6, we quantitatively show that the major sources of reionization are
most likely galaxies with L < L*. Our approach allows us to put stronger
constraints to the LF of galaxies at z ~ 6. To have the Universe completely
ionized at this redshift, the faint-end slope of the LF should be steeper than
$\alpha=-1.6$, which is the value measured at lower redshifts (z ~ 3), unless
either the normalization (Phi*) of the LF or the clumping factor of the ionized
hydrogen has been significantly underestimated. If Phi* is actually lower than
what we assumed by a factor of two, a steep slope close to $\alpha=-2.0$ is
required. Our LF predicts a total of 50 -- 80 z ~ 6 galaxies in the HST Ultra
Deep Field (UDF) to a depth of AB=28.4 mag, which can be used to constraint
both Phi* and $\alpha$. We conclude that the least luminous galaxies existing
at this redshift should reach as low as some critical luminosity in order to
accumulate the entire reionizing photon budget. On the other hand, the
existence of significant amounts of neutral hydrogen at slightly earlier
epochs, e.g. z ~ 7, requires that the least luminous galaxies should not be
fainter than another critical value (i.e., the LF should cut-off at this
point).


title:
Coronal Heating and Acceleration of the High/Low-Speed Solar Wind by
  Fast/Slow MHD Shock Trains

abstract:
  We investigate coronal heating and acceleration of the high- and low-speed
solar wind in the open field region by dissipation of fast and slow
magnetohydrodynamical (MHD) waves through MHD shocks. Linearly polarized
\Alfven (fast MHD) waves and acoustic (slow MHD) waves travelling upwardly
along with a magnetic field line eventually form fast switch-on shock trains
and hydrodynamical shock trains (N-waves) respectively to heat and accelerate
the plasma. We determine one dimensional structure of the corona from the
bottom of the transition region (TR) to 1AU under the steady-state condition by
solving evolutionary equations for the shock amplitudes simultaneously with the
momentum and proton/electron energy equations. Our model reproduces the overall
trend of the high-speed wind from the polar holes and the low-speed wind from
the mid- to low-latitude streamer except the observed hot corona in the
streamer. The heating from the slow waves is effective in the low corona to
increase the density there, and plays an important role in the formation of the
dense low-speed wind. On the other hand, the fast waves can carry a sizable
energy to the upper level to heat the outer corona and accelerate the
high-speed wind effectively. We also study dependency on field strength, $B_0$,
at the bottom of the TR and non-radial expansion of a flow tube, $f_{\rm max}$,
to find that large $B_0/f_{\rm max}\gtrsim 2$ but small $B_0\simeq 2$G are
favorable for the high-speed wind and that small $B_0/f_{\rm max}\simeq 1$ is
required for the low-speed wind.


title:
Cosmic Ray Production of $^6$Li by Virialization Shocks in the Early
  Milky Way

abstract:
  The energy dissipated by virialization shocks during hierarchical structure
formation of the Galaxy can exceed that injected by concomitant supernova (SN)
explosions. Cosmic rays (CRs) accelerated by such shocks may therefore dominate
over SNe in the production of $^6$Li through $\alpha + \alpha$ fusion without
co-producing Be and B. This process can give a more natural account of the
observed $^6$Li abundance in metal-poor stars compared to standard SN CR
scenarios. Future searches for correlations between the $^6$Li abundance and
the kinematic properties of halo stars may constitute an important probe of how
the Galaxy and its halo formed. Furthermore, $^6$Li may offer interesting clues
to some fundamental but currently unresolved issues in cosmology and structure
formation on sub-galactic scales.


title:
Dynamical Mass Constraints on Low-Mass Pre-Main-Sequence Stellar
  Evolutionary Tracks: An Eclipsing Binary in Orion with a 1.0 Msun Primary and
  an 0.7 Msun Secondary

abstract:
  We report the discovery of a double-lined, spectroscopic, eclipsing binary in
the Orion star-forming region. We analyze the system spectroscopically and
photometrically to empirically determine precise, distance-independent masses,
radii, effective temperatures, and luminosities for both components. The
measured masses for the primary and secondary, accurate to ~1%, are 1.01 Msun
and 0.73 Msun, respectively; thus the primary is a definitive pre-main-sequence
solar analog, and the secondary is the lowest-mass star yet discovered among
pre-main-sequence eclipsing binary systems. We use these fundamental
measurements to test the predictions of pre-main-sequence stellar evolutionary
tracks. None of the models we examined correctly predict the masses of the two
components simultaneously, and we implicate differences between the theoretical
and empirical effective temperature scales for this failing. All of the models
predict the observed slope of the mass-radius relationship reasonably well,
though the observations tend to favor models with low convection efficiencies.
Indeed, considering our newly determined mass measurements together with other
dynamical mass measurements of pre-main-sequence stars in the literature, as
well as measurements of Li abundances in these stars, we show that the data
strongly favor evolutionary models with inefficient convection in the stellar
interior, even though such models cannot reproduce the properties of the
present-day Sun.


title: Reflections of AGN Outbursts in the Gaseous Atmosphere of M87

abstract:
  We combined deep Chandra, ROSAT HRI, and XMM-Newton observations of M87 to
study the impact of AGN outbursts on its gaseous atmosphere. Many X-ray
features appear to be a direct result of repetitive AGN outbursts. In
particular, the X-ray cavities around the jet and counter jet are likely due to
the expansion of radio plasma, while rings of enhanced emission at 14 and 17
kpc are probably shock fronts associated with outbursts that began
1-2\times10^7 years ago. The effects of these shocks are also seen in
brightenings within the prominent X-ray arms. On larger scales, ~50 kpc from
the nucleus, depressions in the surface brightness may be remnants of earlier
outbursts. As suggested for the Perseus cluster (Fabian et al.), our analysis
of the energetics of the M87 outbursts argues that shocks may be the most
significant channel for AGN energy input into the cooling flow atmospheres of
galaxies, groups, and clusters. For M87, the mean power driving the shock
outburst, 2.4\times 10^{43} ergs/sec, is three times greater than the radiative
losses from the entire ``cooling flow''. Thus, even in the absence of other
energy inputs, outbursts every 3\times10^7 years are sufficient to quench the
flow.


title: Mass Transfer between Double White Dwarfs

abstract:
  Three periodically variable stars have recently been discovered (V407 Vul,
P=9.5 min; ES Cet, P=10.3 min; RX J0806.3+1527, P=5.3 min) with properties that
suggest that their photometric periods are also their orbital periods, making
them the most compact binary stars known. If true, this might indicate that
close, detached, double white dwarfs are able to survive the onset of mass
transfer caused by gravitational wave radiation and emerge as the
semi-detached, hydrogen-deficient stars known as the AM CVn stars. The
accreting white dwarfs in such systems are large compared to the orbital
separations. This has two effects: first it makes it likely that the mass
transfer stream can hit the accretor directly, and second it causes a loss of
angular momentum from the orbit which can destabilise the mass transfer unless
the angular momentum lost to the accretor can be transferred back to the orbit.
The effect of the destabilisation is to reduce the number of systems which
survive mass transfer by as much as one hundred-fold. In this paper we analyse
this destabilisation and the stabilising effect of a dissipative torque between
the accretor and the binary orbit. We obtain analytic criteria for the
stability of both disc-fed and direct impact accretion, and carry out numerical
integrations to assess the importance of secondary effects, the chief one being
that otherwise stable systems can exceed the Eddington accretion rate. We show
that to have any effect upon survival rates, the synchronising torque must act
on a timescale of order 1000 years or less. If synchronisation torques are this
strong, then they will play a significant role in the spin rates of white
dwarfs in cataclysmic variable stars as well.


title: Atomic lines in infrared spectra for ultracool dwarfs

abstract:
  We provide a set of atomic lines which are suitable for the description of
ultracool dwarf spectra from 10000 to 25000 \AA. This atomic linelist was made
using both synthetic spectra calculations and existing atlases of infrared
spectra of Arcturus and Sunspot umbra. We present plots, which show the
comparison of synthetic spectra and observed Arcturus and Sunspot umbral
spectra for all atomic lines likely to be observable in high resolution
infrared spectra.


title: K-Essential Phantom Energy: Doomsday around the corner?

abstract:
  In spite of its rather weird properties which include violation of the
dominant-energy condition, the requirement of superluminal sound speed and
increasing vacuum-energy density, phantom energy has recently attracted a lot
of scientific and popular interests. In this letter it is shown that in the
framework of a general k-essence model, vacuum-phantom energy leads to a
cosmological scenario having negative sound speed and a big-rip singularity,
where the field potential also blows up, which might occur at an almost
arbitrarily near time in the future that can still be comfortably accommodated
within current observational constraints.


title:
Preparing the COROT space mission: Building a photometric and
  variability database of stars in its field of view

abstract:
  The CNES/European space mission COROT will monitor asteroseismic targets
located in selected fields to probe stellar interiors. Therefore, suitable
candidate targets have to be searched for in order to optimize the scientific
return of the mission. However, to be able to use the asteroseismic tools on
the stars, their physical parameters must be known in advance. In this work, we
detail the process of building a photometric database of all the stars brighter
than V=8.0 mag in the field of view of COROT and the process of selecting
suitable delta Scuti and gamma Dor-type stars for the mission.


title: Neutrino flux variations and solar activity

abstract:
  We investigate temporal variations of the solar neutrino flux in 1970-1997.
The periods of 11, 5 and 2 years have been found in the variations of the
neutrino flux. The results indicate that a periodicity close to 5 years is the
most significant in the data from both the Homestake and GALLEX experiments.
Two groups of the solar activity indices have been distinguished regarding
their interconnection with the neutrino flux series. The first group contains
the indices showing predominantly 11-year period, while a periodicity at
approximately 5 years is observed in the second group. The correlation
coefficients between the neutrino flux and indices from the first group are
negative, with their module not exceeding 0.5. The second group is
characterized by positive correlation with the neutrino counting rates with
coefficients not lower than 0.6. A discussion of findings is presented.


title: New Results on R Aquarii

abstract:
  The first results on new optical data for R Aquarii (based on observations
obtained with the 2.5m INT, the 2.5m NOT and the 3.5m NTT) are presented. The
morphology and kinematics of the nebula, based on data obtained with the NTT
from 1991 to 2000, are discussed. Physical parameters of the outer nebula and
the knotty jet are derived using spectra obtained with the INT in 2001. From
the analysis of all these data we propose that the spectacular knotty inner
structure of R Aqr could result from the interaction of a highly collimated
pulsating young jet with the older hourglass inner nebula.


title:
The study of delta Sct stars in the transition era from ground-based to
  space photometry

abstract:
  The different research teams involved in the study of delta Sct stars have
slightly changed their strategy in the past years. The observational effort to
secure worldwide coverage of case studies is continued, but the specifications
become more severe, especially about target characterization and frequency
resolution.


title: Chemical Abundances and Their Relation with PN Morphological Features

abstract:
  Results appeared since the last APN meeting on the relation between
abundances and PNe morphological features are reviewed here. Statistical
analyses of round, elliptical, and bipolar PNe clearly separate the latter
group as having larger He and N/O abundances. Studies of individual PNe,
including the UV and IR domains, allow a detailed comparison with evolutionary
models for the AGB phase; the abundances of most important elements can be
matched but an 'age-metallicity' problem for the progenitors of He-rich PNe is
implied. Halo abundances do not show strong chemical differences with respect
to the PN rims, but the halos' faintness requires deeper data to confirm it.
Data on the chemistry of microstructures of normal (non H-deficient) PNe are
scarce and generally indicate similar abundances than in the rims. The
exception is the high nitrogen overabundance claimed for FLIERS; preliminary
modeling on new observational data of the microstructures of NGC7009 indicates
that a moderate enrichment of nitrogen can be real.


title: TeV Gamma-Ray Observations and the Origin of Cosmic Rays III

abstract:
  Being primarily devoted to the physics interpretation, the talk starts with
the stereoscopic observation technique pioneered by HEGRA. The search for
Supernova Remnants is reviewed, the need for a consistent theory is argued, and
its elements are outlined. This theory is the basis for models regarding SN
1006 and Cas A. The analysis shows for the first time that emission spectra and
morphological detail are in agreement with the concept that these objects are
representative members of a suspected source population in the Galaxy. The
continuing study of this population is an essential part of the program of the
major new gamma-ray instruments.


title:
Paschen beta emission as a tracer of outflow activity from T-Tauri
  stars, as compared to Optical Forbidden emission

abstract:
  The Paschen beta (1.2822 micron) emission line found in the near-infrared
spectra of T-Tauri stars (TTSs) is believed to trace the accretion of material
onto the central star. We present spectroscopic data which suggests that this
may not always be the case. The technique of spectro-astrometry is used by us
to measure positional displacements in the Pab emission from four T-Tauri
stars, namely DG Tau, V536 Aql, LkHalpha 321 and RW Aur. We also observed the
optical forbidden emission from these sources. Forbidden emission lines are
formed in the outflows that accompany the evolution of protostars and so are
ideal to use as a comparison to confirm that the measured offsets in the Pab
emission are indeed due to outflowing material. Models based on the
magnetospheric accretion theory have been the most successful to date in
explaining the origin of atomic hydrogen emission lines. Yet we see that the
line profiles of the sources showing displacement in their Pab emission all
have features that the magnetospheric accretion model has so far failed to
explain, such as broad full width half maxima, large wings and an absence of
red shifted absorption features. The failure of the models to explain the
presence of large extended wings in the line profiles is particularly
interesting in the context of this study as in all cases it is in the extended
wings that we measure offsets in position with respect to the source.


title: Asphericity Effects in Supernovae

abstract:
  We present a brief summary of asphericity effects in thermonuclear and core
collapse supernovae (SN), and how to distinguish the underlying physics by
their observable signatures. Electron scattering is the dominant process to
produce polarization which is one of the main diagnostical tools. Asphericities
result in a directional dependence of the luminosity which has direct
implications for the use of SNe in cosmology. For core collapse SNe, the
current observations and their interpretations suggest that the explosion
mechanism itself is highly aspherical with a well defined axis and, typically,
axis ratios of 2 to 3. Asymmetric density/chemical distributions and off-center
energy depositions have been identified as crucial for the interpretation of
the polarization $P$. For thermonuclear SNe, polarization turned out to be an
order of magnitude smaller strongly supporting rather spherical, radially
stratified envelopes. Nevertheless, asymmetries have been recognized as
important signatures to probe A) for the signatures of the progenitor system,
B) the global asymmetry with well defined axis, likely to be caused by rotation
of an accreting white dwarf or merging WDs, and C) possible remains of the
deflagration pattern.


title:
Analysis of a Very Massive DA White Dwarf via the Trigonometric Parallax
  and Spectroscopic Methods

abstract:
  By two different methods, we show that LHS 4033 is an extremely massive white
dwarf near its likely upper mass limit for destruction by unstable electron
captures. From the accurate trigonometric parallax reported herein, the
effective temperature (T=10,900 K) and the stellar radius (R=0.00368 R_sun) are
directly determined from the broad-band spectral energy distribution -- the
parallax method. The effective temperature and surface gravity are also
estimated independently from the simultaneous fitting of the observed Balmer
line profiles with those predicted from pure-hydrogen model atmospheres -- the
spectroscopic method (T=10,760 K, log g=9.46). The mass of LHS 4033 is then
inferred from theoretical mass-radius relations appropriate for white dwarfs.
The parallax method yields a mass estimate of 1.310--1.330 M_sun, for interior
compositions ranging from pure magnesium to pure carbon, respectively, while
the spectroscopic method yields an estimate of 1.318--1.335 M_sun for the same
core compositions. This star is the most massive white dwarf for which a robust
comparison of the two techniques has been made.


title: Evolution of Young Neutron Star Envelopes

abstract:
  We extend our initial study of diffusive nuclear burning (DNB) for neutron
stars (NSs) with Hydrogen atmospheres and an underlying layer of proton
capturing nuclei. Our initial study showed that DNB can alter the photospheric
abundance of Hydrogen on surprisingly short timescales ($10^{2-4}\yrs$).
Significant composition evolution impacts the radiated thermal spectrum from
the NS as well as its overall cooling rate. In this paper, we consider the case
when the rate limiting step for the H consumption is diffusion to the burning
layer, rather than the local nuclear timescale. This is relevant for NSs with
surface temperatures in excess of $10^6 {\rm K}$, such as young ($<10^5$ yr)
radio pulsars and accreting NSs in quiescence. When downward diffusion is the
limiting rate in DNB, the rate of H consumption is suppressed by 1-2 orders of
magnitude compared to a DNB estimate that assumes diffusive equilibrium. In
order to apply our ongoing study to young neutron stars, we also include the
important effects of strong magnetic fields ($B \sim 10^{12} {\rm G}$). In this
initial study of magnetic modifications to DNB, we find that the H burning time
is lengthened by 2-3 orders of magnitude for a $10^{12} {\rm G}$ field.
However, even for NSs with dipole field strengths of $10^{12}$ G, we find that
all of the H can be burned before the pulsar reaches an age of $\sim 10^5 \
{\rm yr}$, thus potentially revealing the underlying proton-capturing elements.
Finally, we conclude by providing an overview of what can be learned about
fallback and pulsar winds from measuring the surface composition of a young NS.


title: Blazar Flaring Rates Measured with GLAST

abstract:
  We derive the minimum observing time scales to detect a blazar at a given
flux level with the LAT on GLAST in the scanning and pointing modes. Based upon
Phase 1 observations with EGRET, we predict the GLAST detection rate of blazar
flares at different flux levels. With some uncertainty given the poor
statistics of bright blazars, we predict that a blazar flare with integral flux
>~ 200e-8 ph(> 100 MeV) cm^{-2} s^{-1}, which are the best candidates for
Target of Opportunity pointings and extensive temporal and spectral studies,
should occur every few days.


title: Cosmic Rays and High-Energy Neutrinos from Gamma-Ray Bursts

abstract:
  Several lines of evidence point to a relationship between gamma-ray bursts
(GRBs) and the high mass stars that explode as supernovae. Arguments that GRB
sources accelerate cosmic rays (CRs) are summarized. High-energy neutrino
detection from individual GRBs would mean that they are hadronically dominated,
that is, that the amount of energy deposited in the form of nonthermal hadrons
in GRB blast waves greatly exceeds the radiated energy inferred from their
photon emission spectra. Such a detection would make GRBs the favored candidate
sources of ultra-high energy and super-GZK CRs. Cascade radiation induced by
high-energy hadrons could be detected from GRBs with gamma-ray telescopes.


title: Interstellar Dust

abstract:
  In the interstellar medium of the Milky Way, certain elements -- e.g., Mg,
Si, Al, Ca, Ti, Fe -- reside predominantly in interstellar dust grains. These
grains absorb, scatter, and emit electromagnetic radiation, heat the
interstellar medium by photoelectric emission, play a role in the ionization
balance of the gas, and catalyze the formation of molecules, particularly H2. I
review the state of our knowledge of the composition and sizes of interstellar
grains, including what we can learn from spectral features, luminescence,
scattering, infrared emission, and observed gas-phase depletions. The total
grain volume in dust models which reproduce interstellar extinction is
significantly greater than estimated from observed depletions.
  Dust grains might reduce the gas-phase D/H ratio, providing an alternative
mechanism to explain observed variations in the gas-phase D/H ratio in the
local interstellar medium. Transport in dust grains could cause elemental
abundances in newly-formed stars to differ from interstellar abundances.


title: On equilibrium tides in fully convective planets and stars

abstract:
  We consider the tidal interaction of a fully convective primary star and a
point mass. Using a normal mode decomposition we calculate the evolution of the
primary angular velocity and orbit for arbitrary eccentricity e. The
dissipation acting on the tidal perturbation is associated with convective
turbulence. A novel feature of the Paper is that, to take into account of the
fact that there is a relaxation time t_{c}, being the turn-over time of
convective eddies, associated with the process, this is allowed to act non
locally in time, producing a dependence of the dissipation on tidal forcing
frequency. Results are expressed in terms of the Fourier coefficients of the
tidal potential. We find analytical approximations for these valid for $e>0.2$.
When the tidal response is frequency independent, our results are equivalent to
those obtained in the standard constant time lag approximation. When there is
the frequency dependence of the dissipative response, the evolution can differ
drastically. In that case the system can evolve through a sequence of
spin-orbit corotation resonances with Omega_{r}/Omega_{orb}=n/2, where
Omega_{r} and Omega_{orb} are the rotation and orbital frequencies and n is an
integer. We study this case analytically and numerically.


title: The detailed optical light curve of GRB 030329

abstract:
  (Abridged) We present densely sampled BVRI light curves of the optical
transient associated with the gamma-ray burst GRB 030329, the result of a
coordinated observing campaign conducted at five observatories. Augmented with
published observations of this GRB, the compiled optical dataset contains 2687
photometric measurements, obtained between 78 minutes and 79 days after the
burst. We show that the underlying supernova 2003dh evolved faster than, and
was probably somewhat fainter than the type Ic SN 1998bw, associated with GRB
980425. We find that our data can be described by a broken power-law decay
perturbed by a complex variable component. The early- and late-time decay
slopes are determined to be ~1.1 and ~2, respectively. Assuming this single
power-law model, we constrain the break to lie between ~3 and ~8 days after the
burst. This simple, singly-broken power-law model, derived only from the
analysis of our optical observations, may also account for available multi-band
data, provided that the break happened ~8 days after the burst. The more
complex double-jet model of Berger et al. provides a comparable fit to the
optical, X-ray, mm and radio observations of this event. We detect a
significant change in optical colors during the first day. Our color analysis
is consistent with a cooling break frequency sweeping through the optical band
during the first day. The light curves of GRB 030329 reveal a rich array of
variations, superposed over the mean power-law decay. We find that the early
variations are asymmetric, with a steep rise followed by a relatively slower
(by a factor of about two) decline. The variations maintain a similar time
scale during the first four days, and then get significantly longer.


title:
Outline of the Unified Theory of Spiral and Bar-like Structures in
  Galaxies

abstract:
  This paper presents a new approach to studying galactic structures. They are
considered as the low-frequency normal modes in a disc of orbits precessing at
different angular speeds. Such a concept is an adequate alternative to the
commonly used approach of treating the disc as a set of individual stars
rotating at near-circular orbits around the centre. The problem of determining
the normal modes is reduced to a simple integral equation in the form of the
classical eigen-value problem, where the eigen-value is directly equal to the
pattern speed of the mode, $\Omega_p$. An examination of the general properties
of the basic integral equation shows that two types of solutions exist,
bar-like and spiral. The numerical solutions of both types are obtained. The
characteristic pattern speeds are of the order of the mean orbit precession
speed, although for the bar-modes $\Omega_p$ can markedly exceed the maximum
precessing speed of orbits. It is shown that the bar-mode grows due to the
immediate action of its gravitational field on the stars at the resonance
regions. As for the spiral mode, its excitation is probably due to the inner
Lindblad resonance that can promote mode growth.


title: Formation of Massive Stars via Accretion

abstract:
  The collapse of massive molecular clumps can produce high mass stars, but the
evolution is not simply a scaled-up version of low mass star formation.
Outflows and radiative effects strongly hinder the formation of massive stars
via accretion. A necessary condition for accretion growth of a hydrostatic
object up to high masses M > 20 M_sun (rather than coalescence of optically
thick objects) is the formation of and accretion through a circumstellar disk.
Once the central object has accreted approximately 10 M_sun it has already
evolved to core hydrogen-burning; the resultant main sequence star continues to
accrete material as it begins to photoevaporate its circumstellar disk (and any
nearby disks) on a timescale of 100,000 years, similar to the accretion
timescale. Until the disk(s) is (are) completely photoevaporated, this
configuration is observable as an ultra-compact HII region (UCHII). The final
mass of the central star (and any nearby neighboring systems) is determined by
the interplay between radiation acceleration, UV photoevaporation, stellar
winds and outflows, and the accretion through the disk.
  Several aspects of this evolutionary sequence have been simulated
numerically, resulting in a "proof of concept". This scenario places strong
constraints on the accretion rate necessary to produce high mass stars and
offers an opportunity to test the accretion hypothesis.


title:
Ultraluminous X-ray Sources as Intermediate Mass Black Holes Fed by
  Tidally Captured Stars

abstract:
  The nature of ultraluminous X-ray sources (ULXs) is presently unknown. A
possible explanation is that they are accreting intermediate mass black holes
(IBHs) that are fed by Roche lobe overflow from a tidally captured stellar
companion. We show that a star can circularize around an IBH without being
destroyed by tidal heating (in contrast to the case of M_bh> 10^6 M_sun massive
black holes in galactic centers, where survival is unlikely). We find that the
capture and circularization rate is of the order of 5 \times 10^-8 yr^-1,
almost independently of the cluster's relaxation time. We follow the luminosity
evolution of the binary system during the main sequence Roche lobe overflow
phase and show it can maintain ULX-like luminosities for >10 Myr. In
particular, we show that the ULX in the young cluster MGG-11 in star-burst
galaxy M82, which possibly harbors an IBH, is well explained by this mechanism,
and we predict that \gtrsim 10% of similar clusters with IBHs have a tidally
captured circularized star. The cluster can evaporate on a time-scale shorter
than the lifetime of the binary. This raises the possibility of a ULX that
outlives its host cluster, or even lights up only after the cluster has
evaporated, in agreement with observations of host-less ULXs.


title: Spectroscopic follow-up of FIRBACK-South-Marano bright galaxies

abstract:
  We present optical spectroscopy of the brightest 170 microns sources in the
FIRBACK South Marano (FSM) field. The survey is 90% complete at the 4 sigma
level. The spectra are compared with those of a reference sample of faint IRAS
(60 microns selected) sources observed in the same conditions . The galaxies in
both samples are characterized by a predominance of emission-line spectra and
moderate IR luminosities (10E10.5 < L_IR < 10E12 L_Sun). The fraction of AGN's
is low (about 15%) and the majority of sources are nearby (z<0.3), dusty, star
forming galaxies, with moderate star formation rates (a few 10 solar masses per
year). The infrared emission of the FSM galaxies shows also a colder spectral
energy distribution than was expected.
  The galaxies in both samples (IRAS faint sources and FSM) are essentially
undistinguishable with the available data, and seem to represent a population
of closeby, cold, star forming galaxies rather neglected up to now. Although
their contribution to the far-IR background seems to be low, they deserve a
more detailed study on their own. The contribution of fainter, presumably more
distant, galaxies to the far-IR background will be discussed when we will have
completed the follow-up of the fainter part of this 170 microns survey. It
seems however already clear that the fraction of closeby, cold galaxies is much
larger than expected by the earlier models, at least down to the sensitivity
achieved by this ISO survey.


title: Intrinsic absorbers in BL Lac objects: the XMM-Newton view

abstract:
  We present XMM-Newton observations of four BL Lac objects (1H1219+301,
H1426+428, Markarian 501 and PKS 0548-322), which have been found with past
X-ray missions to contain evidence of broad soft X-ray absorption features.
Observations with the high resolution Reflection Grating Spectrometers on
XMM-Newton provide the best chance yet of investigating these features. No
broad absorption features are observed in any of the objects. Neither do we
find convincing evidence for narrow emission and absorption lines in the RGS
spectra. We discuss the history of observations of broad absorption features in
these four objects, finding that if the features exist then they must be
transient, and that - given the frequency of reported observations of them - we
can rule out the existence of transient broad absorption features in these
objects at 93% confidence.


title: The Puzzles of RX J1856.5-3754: Neutron Star or Quark Star?

abstract:
  We discuss recent Chandra and XMM-Newton observations of the bright isolated
neutron star RX J1856.5-3754 and suggest that the absence of any line features
is due to effects of a high magnetic field strength (~10^13 G). Using different
models for the temperature distribution across the neutron star surface
assuming blackbody emission to fit the optical and X-ray spectrum and we derive
a conservative lower limit of the "apparent" neutron star radius of 16.5 km x
(d/117 pc). This corresponds to the radius for the "true" (de-redshifted)
radius of 14 km for a 1.4 Msun neutron star, indicating a stiff equation of
state at high densities. A comparison of the result with mass-radius diagrams
shows that quark stars and neutron stars with quark matter cores can be ruled
out with high confidence.


title:
The Radio : X-ray Correlation of Cygnus X-3 and other Galactic
  Microquasars

abstract:
  Cygnus X-3, among the Galactic X-ray binaries, is one of the brightest radio
sources. Radio image as well as spectral analysis shows the presence of outflow
in the form of jets. The SED in the X-ray band shows a complicated structure
and evolution. Here we review some recent results of the correlation of the
long-term radio and X-ray emission, in the various states of the source, with
emphasis on the low (hard) state. We compare the results with those of other
common Galactic microquasars, and attempt to provide a consistent picture of
the accretion-ejection mechanism in these types of binaries.


title: Gamma-Ray Bursts observed by XMM-Newton

abstract:
  Analysis of observations with XMM-Newton have made a significant contribution
to the study of Gamma-ray Burst (GRB) X-ray afterglows. The effective area,
bandpass and resolution of the EPIC instrument permit the study of a wide
variety of spectral features. In particular, strong, time-dependent, soft X-ray
emission lines have been discovered in some bursts. The emission mechanism and
energy source for these lines pose major problems for the current generation of
GRB models. Other GRBs have intrinsic absorption, possibly related to the
environment around the progenitor, or possible iron emission lines similar to
those seen in GRBs observed with BeppoSAX. Further XMM-Newton observations of
GRBs discovered by the Swift satellite should help unlock the origin of the GRB
phenomenon over the next few years.


title: The discovery of an evolving dust scattered X-ray halo around GRB 031203

abstract:
  We report the first detection of a time-dependent, dust-scattered X-ray halo
around a gamma-ray burst. GRB 031203 was observed by XMM-Newton starting six
hours after the burst. The halo appeared as concentric ring-like structures
centered on the GRB location. The radii of these structures increased with time
as t^{1/2}, consistent with small-angle X-ray scattering caused by a large
column of dust along the line of sight to a cosmologically distant GRB. The
rings are due to dust concentrated in two distinct slabs in the Galaxy located
at distances of 880 and 1390 pc, consistent with known Galactic features. The
halo brightness implies an initial soft X-ray pulse consistent with the
observed GRB.


title: Proposal for a quantity based data model in the Virtual Observatory

abstract:
  We propose the beginnings of a data model for the Virtual Observatory (VO)
built up from simple ``quantity'' objects. In this paper we present how an
object-oriented, domain (or namespace)-scoped simple quantity may be used to
describe astronomical data. Our model is designed around the requirements that
it be searchable and serve as a transport mechanism for all types of VO data
and meta-data. In this paper we describe this model in terms of an OWL ontology
and UML diagrams. An XML schema is available online.


title: Structure Formation with Mirror Dark Matter: CMB and LSS

abstract:
  In the mirror world hypothesis the mirror baryonic component emerges as a
possible dark matter candidate. An immediate question arises: how the mirror
baryons behave and what are the differences from the more familiar dark matter
candidates as e.g. cold dark matter? In this paper we answer quantitatively to
this question. First we discuss the dependence of the relevant scales for the
structure formation (Jeans and Silk scales) on the two macroscopic parameters
necessary to define the model: the temperature of the mirror plasma (limited by
the Big Bang Nucleosynthesis) and the amount of mirror baryonic matter. Then we
perform a complete quantitative calculation of the implications of mirror dark
matter on the cosmic microwave background and large scale structure power
spectrum. Finally, confronting with the present observational data, we obtain
some bounds on the mirror parameter space.


title: Solving Two Puzzles in One Go: Quintessence from a Decaying Dark Matter

abstract:
  The mystery of the Dark energy is not just its smallness. The extreme fine
tuning of its density in the Early Universe such that it permits galaxy
formation before creating a new inflationary epoch is its other unexplained
aspect. Here we propose a model based on the very slow decay of a Super Heavy
Dark Matter (SDM), presumed candidate for the origin of the Ultra High Energy
Cosmic Rays (UHECRs). A small part of the remnants energy is in the form of a
scalar field which decoheres and behaves like a quintessence field. This model
does not need a special form for the potential and a simple ${\phi}^4$ theory
or an axion like scalar is enough. The equation of state of the Dark Energy
becomes very close to a cosmological constant and is very well consistent with
observations.


title: Cosmology of the Mirror Universe

abstract:
  We describe the implications on the structure formation, the cosmic microwave
background (CMB) and the large scale structure (LSS) for a Universe in which a
significant part of dark matter is made of mirror baryons. Being the
microphysics of the mirror baryons identical to the one of the usual baryons,
we need only two extra thermodynamical parameters to describe our model: the
temperature of the mirror plasma (limited by the BBN) and the amount of mirror
baryonic matter. We extend the Jeans theory in order to study the structure
formation mechanism in linear regime. Using a numerical code, we compute the
temporal evolution of perturbations, the CMB anisotropies and the LSS power
spectra. We show as the decoupling time and the dissipative Silk scale of the
mirror baryons (both being different than for the ordinary ones) are key
features for the evolution of a Mirror Universe, and induces specific
signatures on the power spectra. We analyse the dependence of both CMB and LSS
spectra on the mirror sector temperature and on the amount of mirror baryons.
Confronting with the present observational data, we show that for x < 0.3 the
dark matter could be constituted entirely by mirror baryons, since in this case
mirror baryons at linear scales behave essentially like cold dark matter (CDM)
and substantial deviations are expected only at smaller scales which have
undergone non-linear growth from relatively large redshifts. In the case of x >
0.3 the pattern of the LSS power spectrum excludes the possibility of dark
matter consisting entirely of mirror baryons, but they could present as
admixture to the conventional CDM.


title: A QED Model for the Origin of Bursts from SGRs and AXPs

abstract:
  We propose a model to account for the bursts from soft gamma repeaters (SGRs)
and anomalous X-ray pulsars (AXPs) in which quantum electrodynamics (QED) plays
a vital role. In our theory, that we term ``fast-mode breakdown,''
magnetohydrodynamic (MHD) waves that are generated near the surface of a
neutron star and propagate outward through the magnetosphere will be modified
by the polarization of the vacuum. For neutron star magnetic fields
$B_\rmscr{NS} \gtrsim B_\rmscr{QED} \approx 4.4 \times 10^{13}$ G, the
interaction of the wave fields with the vacuum produces non-linearities in fast
MHD waves that can steepen in a manner akin to the growth of hydrodynamic
shocks. Under certain conditions, fast modes can develop field discontinuities
on scales comparable to an electron Compton wavelength, at which point the wave
energy will be dissipated through electron-positron pair production. We show
that this process operates if the magnetic field of the neutron star is
sufficiently strong and the ratio of the wavelength of the fast mode to its
amplitude is sufficiently small, in which case the wave energy will be
efficiently converted into an extended pair-plasma fireball. The radiative
output from this fireball will consist of hard X-rays and soft $\gamma$-rays,
with a spectrum similar to those seen in bursts from SGRs and AXPs (abridged).


title:
XMM-Newton spectral and timing observations of the millisecond pulsar
  PSR J0218+4232

abstract:
  We present XMM-Newton MOS imaging and PN timing data of the millisecond
pulsar PSR J0218+4232. We confirm the previously detected pulsations of PSR
J0218+4232 and we show that the folded lightcurve is dependent on energy. We
present the broad band (0.2-10.0 keV) spectrum of this millisecond pulsar, as
well as the spectra of: the pulsed emission, the individual pulses, the
interpulse and the non-pulsed region and we compare our results with previous
data from Rosat, BeppoSAX and Chandra. We discuss the results of the spectral
fitting in the context of recent pulsar models.


title:
The CMB Power Spectrum from the Background Emission Anisotropy Scanning
  Telescope (BEAST) Experiment

abstract:
  The Background Emission Anisotropy Scanning Telescope (BEAST) is a 2.2m
off-axis telescope with an 8 element mixed Q (38-45GHz) and Ka (26-36GHz) band
focal plane, designed for balloon borne and ground based studies of the Cosmic
Microwave Background. Here we present the Cosmic Microwave Background (CMB)
angular power spectrum calculated from 682 hours of data observed with the
BEAST instrument. We use a binned pseudo-Cl estimator (the MASTER method). We
find results that are consistent with other determinations of the CMB
anisotropy for angular wavenumber l between 100 and 600. We also perform
cosmological parameter estimation. The BEAST data alone produces a good
constraint on Omega_k = 1-Omega_tot=-0.074 +/- 0.070, consistent with a flat
Universe. A joint parameter estimation analysis with a number of previous CMB
experiments produces results consistent with previous determinations.


title: A Possible Hybrid Scenario for Gas Giant Planet Formation in Rings

abstract:
  The core-accretion mechanism for gas giant formation may be too slow to
create all observed gas giant planets during reasonable gas disk lifetimes, but
it has yet to be firmly established that the disk instability model can produce
permanent bound gaseous protoplanets under realistic conditions. Based on our
recent simulations of gravitational instabilities in disks around young stars,
we suggest that, even if instabilities due to disk self-gravity do not produce
gaseous protoplanets directly, they may create persistent dense rings that are
conducive to accelerated growth of gas giants through core accretion. The rings
occur at and near the boundary between stable and unstable regions of the disk
and appear to be produced by resonances with discrete spiral modes on the
unstable side.


title: Embedding Lagrangian Sink Particles in Eulerian Grids

abstract:
  We introduce a new computational method for embedding Lagrangian sink
particles into an Eulerian calculation. Simulations of gravitational collapse
or accretion generally produce regions whose density greatly exceeds the mean
density in the simulation. These dense regions require extremely small time
steps to maintain numerical stability. Smoothed particle hydrodynamics (SPH)
codes approach this problem by introducing non-gaseous, accreting sink
particles, and Eulerian codes may introduce fixed sink cells. However, until
now there has been no approach that allows Eulerian codes to follow accretion
onto multiple, moving objects. We have removed that limitation by extending the
sink particle capability to Eulerian hydrodynamics codes. We have tested this
new method and found that it produces excellent agreement with analytic
solutions. In analyzing our sink particle method, we present a method for
evaluating the disk viscosity parameter $\alpha$ due to the numerical viscosity
of a hydrodynamics code, and use it to compute $\alpha$ for our Cartesian AMR
code. We also present a simple application of this new method: studying the
transition from Bondi to Bondi-Hoyle accretion that occurs when a shock hits a
particle undergoing Bondi accretion.


title: Evidence for gas accretion in galactic disks

abstract:
  Studies of the HI in galaxies have clearly shown that subtle details of the
HI distribution and kinematics often harbour key information for understanding
the structure and evolution of galaxies. Evidence for the accretion of material
has grown over the past many years and clear signatures can be found in HI
observations of galaxies. We have obtained new detailed and sensitive HI
synthesis observations of three nearby galaxies which are suspected of
capturing small amounts of HI and show that indeed accretion of small amounts
of gas is taking place in these galaxies. This could be the same kind of
phenomenon of material infall as observed in the stellar streams in the halo
and outer parts of our galaxy and M31


title: The Magnetized Universe

abstract:
  Cosmology, high-energy physics and astrophysics are converging on the study
of large-scale magnetic fields. While the experimental evidence for the
existence of large-scale magnetization in galaxies, clusters and superclusters
is rather compelling, the origin of the phenomenon remains puzzling especially
in light of the most recent observations. The purpose of the present review is
to describe the physical motivations and some of the open theoretical problems
related to the existence of large-scale magnetic fields.


title: High-Energy Emission from Presupernovae

abstract:
  The non-thermal emission in the magnetospheres of presupernova collapsing
stars with initial dipole magnetic fields and a certain initial energy
distribution of the charged particles in a magnetosphere is considered. The
analysis of particle dynamics and its emission in the stellar magnetosphere
under collapse show that the collapsing stars can be the powerful sources of a
non-thermal radiation produced by the interaction of charged particles with the
magnetic field. The radiation flux grows with decreasing stellar radius. This
flux can be observed in the form of radiation burst with duration equal to the
stellar collapse time. The radiation flux depends on the distance to the stars,
the particle spectrum and magnetic field in the magnetosphere. The radiation
flux is calculated for various collapsing stars with initial dipole magnetic
fields and an initial power series, relativistic Maxwell, and Boltzmann
particle energy distribution in the magnetosphere. This radiation can be
observed by means of modern astronomical instruments.


title:
Dredge-up and envelope burning in intermediate mass giants of very low
  metallicity

abstract:
  (abbreviated) The evolution of intermediate mass stars at very low
metallicity during their final thermal pulse asymptotic giant branch phase is
studied in detail. As representative examples models with initial masses of
4Msun and 5Msun with a metallicity of Z=0.0001 ([Fe/H] ~ -2.3) are discussed.
The 1D stellar structure and evolution model includes time- and depth dependent
overshooting motivated by hydrodynamical simulations, as well as a full nuclear
network and time-dependent mixing. Particular attention is given to high time
and space resolution to avoid numerical artefacts related to third dredge-up
and hot-bottom burning predictions. The model calculations predict very
efficient third dredge-up which mixes the envelope with the entire intershell
layer or a large fraction thereof, and in some cases penetrates into the C/O
core below the He-shell. In all cases primary oxygen is mixed into the
envelope. The models predict efficient envelope burning during the interpulse
phase. Depending on the envelope burning temperature, oxygen is destroyed to
varying degrees. The combined effect of dredge-up and envelope burning does not
lead to any significant oxygen depletion in any of the cases considered in this
study. The large dredge-up efficiency in our model is closely related to the
particular properties of the H-shell during the dredge-up phase in
low-metallicity very metal poor stars, which is followed here over many thermal
pulses. During the dredge-up phase, the temperature just below the convective
boundary is large enough for protons to burn vigorously when they are brought
into the C-rich environment below the convection boundary by the time- and
depth dependent overshooting. H-burning luminosities of 10^5 to ~2* 10^6L_sun
are generated. [...]


title: Abrupt global events in the Earth's history: a physics perspective

abstract:
  The timeline of the Earth's history reveals quasi-periodicity of the
geological record over the last 542 Myr, on timescales close, in the order of
magnitude, to 1 Myr. What is the origin of this quasi-periodicity? What is the
nature of the global events that define the boundaries of the geological time
scale? I propose that a single mechanism is responsible for all three types of
such events: mass extinctions, geomagnetic polarity reversals, and sea-level
fluctuations. The mechanism is fast, and involves a significant energy release.
The mechanism is unlikely to have astronomical causes, both because of the
energies involved, and because it acts quasi-periodically. It must then be
sought within the Earth itself. And it must be capable of reversing the Earth's
magnetic field. The last requirement makes it incompatible with the consensus
model of the origin of the geomagnetic field - the hydromagnetic dynamo
operating in the Earth's fluid core. In the second part of the paper, I show
that a vast amount of seemingly unconnected geophysical and geological data can
be understood in a unified way if the source of the Earth's main magnetic field
is a ~200-km-thick lithosphere, repeatedly magnetized as a result of
methane-driven oceanic eruptions, which produce ocean flow capable of dynamo
action. The eruptions are driven by the interplay of buoyancy forces and
exsolution of dissolved gas, which accumulates in the oceanic water masses
prone to stagnation and anoxia. Polarity reversals, mass extinctions, and
sequence boundaries are consequences of these eruptions. Unlike the consensus
model of geomagnetism, this scenario is consistent with the paleomagnetic data
showing that "directional changes during a [geomagnetic polarity] reversal can
be astonishingly fast, possibly occurring as a nearly instantaneous jump from
one inclined dipolar state to another in the opposite hemisphere".


title: Possible Spectra of Cosmic Rays Accelerated in Extragalactic Sources

abstract:
  Spectra at the Earth of ultra-high energy cosmic rays (UHECR) from Seyfert
nuclei with red shifts z<=0.0092 and from Blue Lacertae objects (BL Lac's) are
calculated. The spectra are compared with the experimental data. It is shown
that in nearby Seyferts the initial spectrum of the UHECRs is most likely the
exponential one. UHECRs from BL Lac's may have the monoenergetic initial
spectrum with the energy of 10^21 eV to fit to the data. Spectra at the Earth
derived in these two models are very similar if there is no Bl Lac's with red
shifts z<0.02. The maximal energy in cosmic rays seemingly does not exceed
10^21 eV. In calculations we used red shift distributions of the objects
according to the recent (2001) catalogue of active nuclei by Veron-Cetty and
Veron (see ref. in the text).


title:
Sensitivity of Core-Collapse Supernovae to Neutrino Luminosity in Cases
  of Anisotropic Neutrino Radiation

abstract:
  We demonstrate the importance of anisotropic neutrino radiation in the
mechanism of core-collapse supernova explosions. Through a new parameter study
with a fixed radiation field of neutrinos, we show that global anisotropy of
the neutrino radiation is the most effective mechanism of increasing the
explosion energy when the total neutrino luminosity is given. We discuss the
reason why, and demonstrate how sensitively the success of a supernova
explosion depends on the neutrino luminosity.


title: Radioactivity of the Key Isotope 44Ti in SN 1987A

abstract:
  We investigate radioactivity from the decay sequence of 44Ti in a young
supernova remnant SN 1987A. We perform Monte-Carlo simulations of degradation
of the nuclear lines to explain a late-time bolometric luminosity which is
estimated from optical and near-infrared observation at 3600 days after the
explosion. Assuming the distance to LMC in between 45.5 and 52.1 kpc, we have
obtained the initial 44Ti mass of (0.82-2.3) 10^{-4} solar mass within the
current uncertainty of the physical quantities. The resulting fluxes of gamma-
and hard X-rays emerged from the 44Ti decay are estimated and compared with the
line sensitivity of the INTEGRAL/SPI on board and that of NeXT X-ray satellite
planned to be launched in 2010. The effect of 44Ti ionization on the estimated
fluxes is briefly remarked.


title:
The Cosmic Quartet - Cosmological Parameters of a Smoothed Inhomogeneous
  Spacetime

abstract:
  We discuss the relation between `bare' cosmological parameters as the true
spatial average characteristics that determine the cosmological model, and the
parameters interpreted by observers with a `Friedmannian bias', i.e., within a
homogeneous space geometry. We may say that the latter are `dressed' by the
smoothed-out geometrical inhomogeneities of the surveyed spatial region. We
identify two effects that quantify the difference between `bare' and `dressed'
parameters: `curvature backreaction' and `volume effect'. An estimate of the
latter is given in terms of a simple geometrical example.


title: The Formation of Self-Gravitating Cores in Turbulent Magnetized Clouds

abstract:
  We use ZEUS-MP to perform high resolution, three-dimensional, super-Alfvenic
turbulent simulations in order to investigate the role of magnetic fields in
self-gravitating core formation within turbulent molecular clouds. Statistical
properties of our super-Alfvenic model without gravity agree with previous
similar studies. Including self-gravity, our models give the following results.
They are consistent with the turbulent fragmentation prediction of the core
mass distribution of Padoan & Nordlund. They also confirm that local
gravitational collapse is not prevented by magnetohydrodynamic waves driven by
turbulent flows, even when the turbulent Jeans mass exceeds the mass in the
simulation volume. Comparison of results between 256^3 and 512^3 zone
simulations reveals convergence in the collapse rate. Analysis of
self-gravitating cores formed in the simulation shows that: (1) All cores
formed are magnetically supercritical by at least an order of magnitude. (2) A
power law relation between central magnetic field strength and density B_c
propto rho_c^{1/2} is observed despite the cores being strongly supercritical.
(3) Specific angular momentum j propto R^{3/2} for cores with radius R. (4)
Most cores are prolate and triaxial in shape, in agreement with the results of
Gammie et al.


title: Dynamics of gas sphere under self-gravity

abstract:
  A new dynamical solution for a gas sphere under self-gravity is presented to
describe a development of a gas sphere from a motion-less state to a state of
expansion with a constant speed and a reflection phenomenon in the dynamics of
the surface of the sphere.


title:
Importance of Prolate Neutrino Radiation in Core-Collapse Supernovae:
  The Reason for the Prolate Geometry of SN1987A?

abstract:
  We have carried out 2-D simulations of core-collapse supernova explosions.
The local neutrino radiation field is assumed to have its maximum value either
at the symmetry (polar) axis or on the equatorial plane. These lead to the
prolate and oblate explosions, respectively. We find that the gain of the
explosion energy in the prolate explosion evolves more predominately than that
in the oblate one when the total neutrino luminosity is given. Namely, the
prolate explosion is more energetic than the oblate one.
  One of the authors (Shimizu et al. 2001) showed for the first time that
globally anisotropic neutrino radiation produces more powerful explosion than
the spherical neutrino radiation does. In our previous study (Madokoro et al.
2003), we improved the numerical code of Shimizu et al. and demonstrated that
the globally anisotropic neutrino radiation yields more energetic explosion
than spatially-fluctuated neutrino radiation does. Together with the result of
this paper, we conclude that the globally anisotropic (prolate) neutrino
radiation is the most effective way of increasing the explosion energy among
various types of explosions investigated in these studies. We discuss the
reason for this. Our result is suggestive of the fact that the expanding
materials of SN1987A is observed to have a prolate geometry.


title:
Confirmation of non-thermal hard X-ray excess in the Coma cluster from
  two epoch observations

abstract:
  We report the hard X-ray spectrum of the Coma cluster obtained using the PDS
data of two independent BeppoSAX observations performed with a time interval of
about three years. In both the spectra a non thermal excess with respect to the
thermal emission is present at a confidence level of ~ 3.4 sigma. The combined
spectrum obtained by adding up the two spectra allows a measurement of the
excess at the level of ~ 4.8 sigma at energies above 20 keV. The analysis of
the full BeppoSAX data set provides a revised non-thermal X-ray flux which is
slightly lower than that previously estimated (Fusco-Femiano et al. 1999) and
in agreement with that measured by two RXTE observations. The analysis of the
offset fields in our Coma observations provides a possible flux determination
of the BL Lac object 1ES 1255+244.


title: Hubble Diagrams of Type Ia Supernovae in the Near Infrared

abstract:
  From observations of 7 Type Ia supernovae obtained during the last four years
at the Las Campanas and Cerro Tololo Inter-American Observatories, along with
previous published data for 9 supernovae, we present JHK Hubble diagrams and
derive absolute magnitudes at maximum light of 16 objects out to a redshift of
0.038. On the scale of H_0 = 72 km/s/Mpc we find mean absolute magnitudes at
maximum of -18.57, -18.24, and -18.42 for J, H, and K, respectively, with
1-sigma uncertainties of the distributions of values of +/- 0.14, 0.18, and
0.12 mag. The data indicate no significant decline rate relations for the
infrared. Thus, Type Ia SNe at maximum brightness appear to be standard candles
in the infrared at the +/- 0.20 mag level or better. The minimum requirements
for obtaining the distance to a Type Ia SN are: reasonably accurate values of
Delta m_15(B) and T(B_max), and one night of infrared data in the -12 to +10 d
window with respect to T(B_max).


title: Neutrino induced showering from the Earth

abstract:
  Ultra High Energy, UHE, Neutrino Astronomy should be soon tested looking
toward the Earth. At present High Energy Neutrino Astronomy is searched by
AMANDA, ANTARES underground detectors looking for its consequent unique muons
secondary track. We suggest a higher energy Tau Neutrino Astronomy based on
Horizontal and Upward Tau Air-Showers escaping from the Earth. These Tau
air-showers greatly amplifies the single tau track by an abundant secondary
tail (billions of electron pairs, gamma and tens of millions muon bundles)
spread in huge areas (kilometer size) easily observable (even partially) from
high mountains, balloon or satellite array detectors. Possible early evidence
of such a New Neutrino UPTAUs or HORTAUs (Upward or Horizontal Tau Air-Showers)
Astronomy may be already found in rare BATSE gamma records of brief up-going
gamma showers named Terrestrial Gamma Flashes (TGF). The TGF features, energy
and arrival clustering are well tuned to upward tau air-showers. Future
confirmation of the Neutrino Tau Astronomy must be found in detectors as EUSO,
seeking for Upward-Horizontal air-shower events: indeed even minimal,
guaranteed, GZK neutrino fluxes may be observed if EUSO threshold reaches
10^{19} eV or lower energies by enlarging its telescope size


title: Composition of the Galactic bulge

abstract:
  We present detailed abundance results for 9 Galactic bulge stars in Baade's
Window, based on HIRES (R=45,000--60,000) spectra taken with the Keck I
telescope.
  The alpha elements show non-uniform enhancements relative to the Solar
neighborhood trends: Mg and Si are enhanced in all our bulge stars by
$\sim$0.5--0.3 dex, showing a slight decrease with increasing [Fe/H]. Oxygen is
enhanced in most bulge stars, similar to the Galactic halo, but the [O/Fe]
ratios suddenly decline beginning at [Fe/H]=$-$0.5 dex, with a slope consistent
with no oxygen production in the bulge for [Fe/H]$\geq$$-$0.5 dex. The observed
production of magnesium in the absence of oxygen synthesis appears to be
inconsistent with current predictions for supernova nucleosynthesis yields; we
suggest that this may be connected to the Wolf-Rayet phenomenon, which occurs
in the pertinent metallicity range. The trend of [Ti/Fe] shows an enhancement
relative to the solar neighborhood of $\sim$0.3 dex, but declines somewhat by
solar metallicity; thus, the Ti trend is less extreme than found by McWilliam &
Rich (1994, MR94). For metal-poor bulge stars calcium is enhanced by $\sim$0.3
dex, similar to the Galactic halo, but in our bulge stars with
[Fe/H]$\geq$$-$0.5, Ca show a slight deficiency relative to the solar
neighborhood value, consistent with the findings of MR94; this may indicate a
slightly top-heavy IMF as suggested by MR94 and McWilliam (1997). Aluminum is
enhanced in all our Galactic bulge giant stars by $\sim$0.25 dex; we argue that
this is consistent with nucleosynthesis dominated by type II supernova events
(SNII), implied by the Mg and Si enhancements. (Abridged)


title: Solar Neutrino Constraints on the BBN Production of Li

abstract:
  Using the recent WMAP determination of the baryon-to-photon ratio, 10^{10}
\eta = 6.14 to within a few percent, big bang nucleosynthesis (BBN)
calculations can make relatively accurate predictions of the abundances of the
light element isotopes which can be tested against observational abundance
determinations. At this value of \eta, the Li7 abundance is predicted to be
significantly higher than that observed in low metallicity halo dwarf stars.
Among the possible resolutions to this discrepancy are 1) Li7 depletion in the
atmosphere of stars; 2) systematic errors originating from the choice of
stellar parameters - most notably the surface temperature; and 3) systematic
errors in the nuclear cross sections used in the nucleosynthesis calculations.
Here, we explore the last possibility, and focus on possible systematic errors
in the He3(\alpha,\gamma)Be7 reaction, which is the only important Li7
production channel in BBN. The absolute value of the cross section for this key
reaction is known relatively poorly both experimentally and theoretically. The
agreement between the standard solar model and solar neutrino data thus
provides additional constraints on variations in the cross section (S_{34}).
Using the standard solar model of Bahcall, and recent solar neutrino data, we
can exclude systematic S_{34} variations of the magnitude needed to resolve the
BBN Li7 problem at > 95% CL. Additional laboratory data on
He3(\alpha,\gamma)Be7 will sharpen our understanding of both BBN and solar
neutrinos, particularly if care is taken in determining the absolute cross
section and its uncertainties. Nevertheless, it already seems that this
``nuclear fix'' to the Li7 BBN problem is unlikely; other possible solutions
are briefly discussed.


title:
On the Infrared, Optical and High Energy Emission from the Anomalous
  X-Ray Pulsar 4U 0142+615

abstract:
  We show that the observed pulsed optical emission of the anomalous X-ray
pulsar 4U 0142+61 can be accounted for by both the magnetar outer gap models
and the disk-star dynamo gap models, therefore is not an evidence in favor of
one of these models as its responsible mechanism. Nevertheless, the estimated
high energy gamma-ray spectra from these models have different power-low
indices, and can be tested by future observations of the Gamma-ray Large-Area
Space Telescope (GLAST). Furthermore, we show by analytical estimations that
the expectations of a standard disk model is in agreement with the observed
unpulsed optical and infrared luminosities of the AXP 4U 0142+61.


title:
Color Effects Associated with the 1999 Microlensing Brightness Peaks in
  Gravitationally Lensed Quasar Q2237+0305

abstract:
  Photometry of the Q2237+0305gravitational lens in VRI spectral bands with the
1.5-m telescope of the high-altitude Maidanak observatory in 1995-2000 is
presented. Monitoring of Q2237+0305 in July-October 2000, made at nearly daily
basis, did not reveal rapid (night-to-night and intranight) variations of
brightness of the components during this time period. Rather slow changes of
magnitudes of the components were observed, such as 0.08 mag fading of B and C
components and 0.05 mag brightening of D in R band during July 23 - October 7,
2000. By good luck three nights in 1999 were almost at the time of the strong
brightness peak of image C, and approximately in the middle of the ascending
slope of the image A brightness peak. The C component was the most blue one in
the system in 1998 and 1999, having changed its (V-I) color from 0.56 mag to
0.12 mag since August 1997, while its brightness increased almost 1.2 mag
during this time period. The A component behaved similarly between August 1998
and August 2000, having become 0.47 mag brighter in R, and at the same time,
0.15 mag bluer. A correlation between the color variations and variations of
magnitudes of the components is demonstrated to be significant and reaches
0.75, with a regression line slope of 0.33. A color (V-I) vrs color (V-R) plot
shows the components settled in a cluster, stretched along a line with a slope
of 1.31. Both slopes are noticeably smaller than those expected if a standard
galactic interstellar reddening law were responsible for the differences
between the colors of images and their variations over time. We attribute the
brightness and color changes to microlensing of the quasar's structure, which
we conclude is more compact at shorter wavelengths, as predicted by most quasar
models featuring an energizing central source.


title: Calculation of Muon Fluxes at the Small Atmospheric Depths

abstract:
  Precise knowledge of the hadronic interaction between primary cosmic rays and
atmospheric nuclei is very important and fundamental to study atmospheric
neutrinos and their oscillations. We studied hadronic interaction models using
the data of primary and secondary cosmic rays observed by BESS experiments. By
comparing the observed spectra with the ones calculated by several interaction
models, we found DPMJET-III is most favored among them.


title:
Two-dimensional, Time-dependent, Multi-group, Multi-angle Radiation
  Hydrodynamics Test Simulation in the Core-Collapse Supernova Context

abstract:
  We have developed a time-dependent, multi-energy-group, and multi-angle
(S$_n$) Boltzmann transport scheme for radiation hydrodynamics simulations, in
one and two spatial dimensions. The implicit transport is coupled to both 1D
(spherically-symmetric) and 2D (axially-symmetric) versions of the explicit
Newtonian hydrodynamics code VULCAN. The 2D variant, VULCAN/2D, can be operated
in general structured or unstructured grids and though the code can address
many problems in astrophysics it was constructed specifically to study the
core-collapse supernova problem. Furthermore, VULCAN/2D can simulate the
radiation/hydrodynamic evolution of differentially rotating bodies. We
summarize the equations solved and methods incorporated into the algorithm and
present results of a time-dependent 2D test calculation. A more complete
description of the algorithm is postponed to another paper. We highlight a 2D
test run that follows for 22 milliseconds the immediate post-bounce evolution
of a collapsed core. We present the relationship between the anisotropies of
the overturning matter field and the distribution of the corresponding flux
vectors, as a function of energy group. This is the first 2D multi-group,
multi-angle, time-dependent radiation/hydro calculation ever performed in core
collapse studies. Though the transport module of the code is not gray and does
not use flux limiters (however, there is a flux-limited variant of VULCAN/2D),
it still does not include energy redistribution and most velocity-dependent
terms.


title:
A Unified Jet Model of X-Ray Flashes, X-Ray-Rich Gamma-Ray Bursts, and
  Gamma-Ray Bursts: I. Power-Law-Shaped Universal and Top-Hat-Shaped Variable
  Opening-Angle Jet Models

abstract:
  HETE-2 has provided strong evidence that the properties of X-Ray Flashes
(XRFs), X-ray-rich GRBs, and GRBs form a continuum, and therefore that these
three kinds of bursts are the same phenomenon. A key feature found by HETE-2 is
that the density of bursts is roughly constant per logarithmic interval in
burst fluence S_E and observed spectral peak energy Ep_obs, and in
isotropic-equivalent energy Eiso and rest frame spectral peak energy Epeak. In
this paper, we explore a unified jet model of all three kinds of bursts, using
population synthesis simulations of the bursts and detailed modeling of the
instruments that detect them. We show that both a variable jet opening-angle
model in which the emissivity is a constant independent of the angle relative
to the jet axis and a universal jet model in which the emissivity is a
power-law function of the angle relative to the jet axis can explain the
observed properties of GRBs reasonably well. However, if one tries to account
for the properties of all three kinds of bursts in a unified picture, the extra
degree of freedom available in the variable jet opening-angle model enables it
to explain the observations reasonably well while the power-law universal jet
model cannot. The variable jet opening-angle model of XRFs, X-ray-rich GRBs,
and GRBs implies that the energy Egamma radiated in gamma rays is ~ 100 times
less than has been thought, and that most GRBs have very small jet opening
angles (~ half a degree). It also implies that there are ~ 10^4 - 10^5 more
bursts with very small jet opening angles for every burst that is observable.
If this is the case, the rate of GRBs could be comparable to the rate of Type
Ic core collapse supernovae.


title:
A Deep, Wide Field, Optical, and Near Infrared Catalog of a Large Area
  around the Hubble Deep Field North

abstract:
  We have conducted a deep multi-color imaging survey of 0.2 degrees^2 centered
on the Hubble Deep Field North (HDF-N). We shall refer to this region as the
Hawaii-HDF-N. Deep data were collected in U, B, V, R, I, and z' bands over the
central 0.2 degrees^2 and in HK' over a smaller region covering the Chandra
Deep Field North (CDF-N). The data were reduced to have accurate relative
photometry and astrometry across the entire field to facilitate photometric
redshifts and spectroscopic followup. We have compiled a catalog of 48,858
objects in the central 0.2 degrees^2 detected at 5 sigma significance in a 3"
aperture in either R or z' band. Number counts and color-magnitude diagrams are
presented and shown to be consistent with previous observations. Using color
selection we have measured the density of objects at 3<z<7. Our multi-color
data indicates that samples selected at z>5.5 using the Lyman break technique
suffer from more contamination by low redshift objects than suggested by
previous studies.


title: Short-Term Radio-X-ray Correlations of Cygnus X-1

abstract:
  We analyze simultaneous radio-X-ray data of Cygnus X-1 from the Ryle
telescope (RT) and RXTE over more than 4 a. We show that apparent correlations
on short time scales in the lightcurves of Cyg X-1 are probably the
coincidental outcome of white noise statistics.


title:
Nucleosynthesis in The Oxygen-Rich Supernova Remnant G292.0+1.8 from
  Chandra X-Ray Spectroscopy

abstract:
  We continue our analysis of the Galactic oxygen-rich supernova remnant (SNR)
G292.0+1.8, which was observed with the {\it Chandra X-ray Observatory}. The
high angular resolution {\it Chandra} data resolve metal-rich ejecta knots as
well as the shocked circumstellar medium. X-ray emission from the ejecta
material in G292.0+1.8 is dominated by highly ionized O, Ne and Mg. Measured
abundance ratios suggest that this material was produced during the hydrostatic
evolution of the massive progenitor star. In contrast to Cassiopeia A, there is
little evidence for X-ray-emitting ejecta from explosive nucleosynthesis, i.e.,
material enriched in Si, S, and particularly, Fe. This limits the amount of
mixing or overturning of deep ejecta material in G292.0+1.8 and suggests that
the ejecta are strongly stratified by composition and that the reverse shock
has not propagated to the Si/S or Fe-rich zones. On the other hand, the bright
equatorial belt is dominated by X-ray emission with normal chemical
composition, which supports shocked dense circumstellar material for its
origin. We find that the thermal pressure in the SNR is much higher than the
pressure in the pulsar wind nebula (PWN), indicating that the reverse shock has
not yet begun to interact with the PWN.


title:
Near-IR spectroscopy of asteroids 21 Lutetia, 89 Julia, 140 Siwa, 2181
  Fogelin, and 5480 (1989YK8), potential targets for the Rosetta mission;
  remote observations campaign on IRTF

abstract:
  In the frame of the international campaign to observe potential target
asteroids for the Rosetta mission, remote observations have been carried out
between Observatoire de Paris, in Meudon-France, and the NASA Infrared
Telescope Facility on Mauna Kea. The SpeX instrument was used in the 0.8-2.5
microns spectral region, for two observing runs in March and June 2003.
  This paper presents near-IR spectra of the asteroids 21 Lutetia, 89 Julia,
140 Siwa, 2181 Fogelin, and 5480 (1989YK8).
  Near-IR spectra of the asteroids 21 Lutetia and 140 Siwa are flat and
featureless.
  The spectrum of 89 Julia reveals absorption bands around 1 and 2 microns,
which may indicate the presence of olivine and olivine-pyroxene mixtures and
confirm the S-type designation.
  The small main-belt asteroids 2181 Fogelin and 5480 (1989YK8) are
investigated spectroscopically for the first time. Near-IR spectra of these
asteroids also show an absorption feature around 1 micron, which could be and
indicator of igneous/metamorphic surface of the objects; new observations in
visible as well as thermal albedo data are necessary to draw a reliable
conclusion on the surface mineralogy of both asteroids.


title: New biology of red rain extremophiles prove cometary panspermia

abstract:
  This paper reports the extraordinary biology of the microorganisms from the
mysterious red rain of Kerala, India. These chemosynthetic organisms grow
optimally at an extreme high temperature of 300 degrees C in hydrothermal
conditions and can metabolize inorganic and organic compounds including
hydrocarbons. Stages found in their life cycle show reproduction by a special
multiple fission process and the red cells found in the red rain are identified
as the resting spores of these microbes. While these extreme hyperthermophiles
contain proteins, our study shows the absence of DNA in these organisms,
indicating a new primitive domain of life with alternate thermostable genetics.
This new biology proves our earlier hypothesis that these microbes are of
extraterrestrial origin and also supports our earlier argument that the
mysterious red rain of Kerala is due to the cometary delivery of the red spores
into the stratosphere above Kerala.


title:
FUSE Observations of Galactic and Intrinsic Absorption in the Spectrum
  of the Seyfert 1 Galaxy 2MASX J21362313-6224008

abstract:
  We present the far-ultraviolet spectrum of the Seyfert 1 galaxy 2MASX
J21362313-6224008 obtained with the Far Ultraviolet Spectroscopic Explorer
(FUSE). The spectrum features absorption from Galactic OVI at two velocities
and redshifted HI Lyman beta and gamma, CII, CIII, and O VI. The redshifted
absorption features represent a single kinematic component blueshifted by ~310
km/s relative to the AGN. We use photoionization models to derive constraints
on the physical parameters of the absorbing gas. An alternative interpretation
for the absorption lines is also proposed, whereby the absorbing gas is
associated with an intervening galaxy cluster.


title:
New Interstellar Dust Models Consistent with Extinction, Emission, and
  Abundance Constraints

abstract:
  We present new interstellar dust models which have been derived by
simultaneously fitting the far-ultraviolet to near-infrared extinction, the
diffuse infrared (IR) emission and, unlike previous models, the elemental
abundance constraints on the dust for different interstellar medium abundances,
including solar, F and G star, and B star abundances. The fitting problem is a
typical ill-posed inversion problem, in which the grain size distribution is
the unknown, which we solve by using the method of regularization. The dust
model contains various components: PAHs, bare silicate, graphite, and amorphous
carbon particles, as well as composite particles containing silicate, organic
refractory material, water ice, and voids. The optical properties of these
components were calculated using physical optical constants. As a special case,
we reproduce the Li & Draine (2001) results, however their model requires an
excessive amount of silicon, magnesium, and iron to be locked up in dust: about
50 ppm (atoms per million of H atoms), significantly more than the upper limit
imposed by solar abundances of these elements, about 34, 35, and 28 ppm,
respectively. A major conclusion of this paper is that there is no unique
interstellar dust model that simultaneously fits the observed extinction,
diffuse IR emission, and abundances constraints.


title: Visibility of Old Supernova Remnants in HI 21-cm Emission Line

abstract:
  We estimate the number of old, radiative supernova remnants (SNRs) detectable
in HI 21-cm emission line in the Galaxy. According to our result, the
contamination due to the Galactic background HI emission limits the number of
visible SNRs to 270, or 9% of the total HI SNRs. The telescope sensitivity
further limits the number. We compare the result with observations to find that
the observed number (< 25) of HI SNRs is much less than the expected. A
plausible explanation is that previous observational studies, which were made
toward the SNRs identified mostly in radio continuum, missed most of the HI
SNRs because they are too faint to be visible in radio continuum. We propose
that the faint, extended HI 21-cm emission line wings protruding from the
Galactic background HI emission in large-scale (l, v) diagrams could be
possible candidates for HI SNRs, although our preliminary result shows that
their number is considerably less than the expected in the inner Galaxy. We
conclude that a possible explanation for the small number of \schi SNRs in the
inner Galaxy is that the interstellar space there is largely filled with a very
tenuous gas as in the three-phase ISM model.


title:
In-medium ion mass renormalization and lattice vibrations in the neutron
  star crust

abstract:
  The inner crust of a neutron star consists of nuclei immersed in a superfluid
neutron liquid. As these nuclei move through the fermionic medium they bring it
into motion as well. As a result their mass is strongly renormalized and the
spectrum of the ion lattice vibrations is significantly affected. Consequently
we predict that the specific heat and the lattice thermal energy of the Coulomb
crystal at these densities are noticeably modified.


title: Nuclear hydrodynamics in the inner crust of neutron stars

abstract:
  In the inner crust of a neutron star, due to the high density and pressure,
nuclei which are still present, are immersed in a neutron superfluid. One then
expects that the dynamical properties of nuclei are significantly affected. In
order to estimate the magnitude of the effect associated with the presence of a
superfluid medium, we formulate the hydrodynamical approach to the nuclear
dynamics in the inner crust of neutron stars. We calculate the renormalized
nuclear mass and the strength of the medium-induced interaction between nuclei.
We argue that these effects noticeably modify the properties of the Coulomb
crystal in the inner crust.


title: Cosmic internal symmetry in a finite universe

abstract:
  Cosmic internal symmetry (COINS) relates cosmic vacuum, dark matter, baryons
and radiation, in a finite universe. Evidence for COINS comes from the
concordance data, including the WMAP data. COINS is behind 1)the cosmic
coincidence, 2)the spatial flatness, 3)cosmic entropy, 4)initial amplitude of
cosmic perturbations. COINS suggests also a solution to the naturalnes problem.
COINS is due to the electroweak-scale physics or multi-dimension physics, if
macroscopic extra dimensions really exist.


title:
XMM-Newton and VLT observations of the isolated neutron star 1E
  1207.4-5209

abstract:
  In August 2002, XMM-Newton devoted two full orbits to the observation of 1E
1207.4-5209, making this isolated neutron star the most deeply scrutinized
galactic target of the mission. Thanks to the high throughput of the EPIC
instrument, ~360,000 photons were collected from the source, allowing for a
very sensitive study of the temporal and spectral behaviour of this object. The
spectral data, both time-averaged and phase-resolved, yield one compelling
interpretation of the observed features: cyclotron absorption from one
fundamental (~0.7 keV) and three harmonics, at ~1.4, ~2.1 and ~2.8 keV.
Possible physical consequences are discussed, also on the basis of the obvious
phase variations of the features' shapes and depths. We also present deep VLT
optical data which we have used to search for a counterpart, with negative
results down to ~27.


title:
Driving spiral arms in the circumstellar disks of HD 100546 and HD
  141569A

abstract:
  With 2D hydrodynamical simulations of disks perturbed externally by stars,
brown dwarfs or planets we investigate possible scenarios that can account for
the spiral structure in circumstellar disks. We consider two scenarios, spiral
structure driven by an external bound planet or low mass star and that excited
by a previous stellar close encounter or flyby. We find that both scenarios
produce morphology similar to that observed in the outer disks of HD 141569A
and HD 100546; moderately open 2-armed outer spiral structure. The outer
two-armed spiral structure observed in the disk of HD 141569A is qualitatively
reproduced with tidal perturbations from its companion binary HD 141569B,C on a
prograde orbit near periapse. Our simulation accounts for the outer spiral
arms, but is less successful than the secular model of Augereau and Papaloizou
at matching the lopsidedness or asymmetry of the disk edge at 300AU. The disk
has been previously truncated by the tidal force from the binary. A bound
object (stellar or planetary) is unlikely to explain the spiral structure in HD
100546. A co-eval planet or brown dwarf in the disk of sufficient mass to
account for the amplitude of the spiral structure would be detectable in NICMOS
and STIS images, however existing images reveal no such object. A previous
encounter could explain the observed structure, provided that the encounter
occurred less than a few thousand year ago. The object responsible for causing
the spiral structure must then be within a few arcminutes of the star. However,
the USNO-B proper motion survey reveals no candidate object. Moreover, the
probability that a field star encountered HD 100546 in the past few thousand
years is very low.


title:
Nonlinear Pulsations in Differentially Rotating Neutron Stars:
  Mass-Shedding-Induced Damping and Splitting of the Fundamental Mode

abstract:
  We study small-amplitude, nonlinear pulsations of uniformly and
differentially rotating neutron stars employing a two-dimensional evolution
code for general-relativistic hydrodynamics. Using Fourier transforms at
several points inside the star, both the eigenfrequencies and two-dimensional
eigenfunctions of pulsations are extracted. The centrifugal forces and the
degree of differential rotation have significant effects on the
mode-eigenfunction. We find that near the mass-shedding limit, the pulsations
are damped due to shocks forming at the surface of the star. This new damping
mechanism may set a small saturation amplitude for modes that are unstable to
the emission of gravitational waves. After correcting for the assumption of the
Cowling approximation (used in our numerical code), we construct empirical
relations that predict the range of gravitational-wave frequencies from
quasi-periodic post-bounce oscillations in the core collapse of massive stars.
We also find that the fundamental quasi-radial mode is split, at least in the
Cowling approximation and mainly in differentially rotating stars, into two
different sequences.


title: Exploring the Nature of Weak Chandra Sources near the Galactic Centre

abstract:
  We present early results from the first IR imaging of the weak X-ray sources
discovered in a recent Chandra survey towards the Galactic Centre. From our VLT
observations we will identify likely counterparts to a sample of the hardest
sources in order to place constraints on the nature of this previously unknown
population.


title: Reanalysis of Copernicus Measurements on Interstellar Carbon Monoxide

abstract:
  We used archival data acquired with the Copernicus satellite to reexamine CO
column densities because self-consistent oscillator strengths are now
available. Our focus is on lines of sight containing modest amounts of
molecular species. Our resulting column densities are small enough that
self-shielding from photodissociation is not occurring in the clouds probed by
the observations. While our sample shows that the column densities of CO and H2
are related, no correspondence with the CH column density is evident. The case
for the CH+ column density is less clear. Recent chemical models for these
sight lines suggest that CH is mainly a by-product of CH+ synthesis in low
density gas. The models are most successful in reproducing the amounts of CO in
the densest sight lines. Thus, much of the CO absorption must arise from denser
clumps along the line of sight to account for the trend with H2.


title:
Comparing AMR and SPH Cosmological Simulations: I. Dark Matter &
  Adiabatic Simulations

abstract:
  We compare two cosmological hydrodynamic simulation codes in the context of
hierarchical galaxy formation: The SPH code GADGET, and the Eulerian AMR code
ENZO. Both codes represent dark matter with the N-body method, but use
different gravity solvers and fundamentally different approaches to
hydrodynamics. We compare the GADGET `entropy conserving' SPH formulation with
two ENZO methods: The piecewise parabolic method (PPM), and the artificial
viscosity-based scheme used in the ZEUS code. In this paper we focus on a
comparison of cosmological simulations that follow either only dark matter, or
also adiabatic baryonic gas. The dark matter-only runs agree generally quite
well, provided ENZO is run with a comparatively fine root grid and a low
overdensity threshold for mesh refinement, otherwise the abundance of low-mass
halos is suppressed. This is due to the hierarchical particle-mesh method used
to compute gravitational forces in ENZO, which tends to deliver lower force
resolution than the tree algorithm of GADGET. At comparable force resolution,
we find that the latter offers substantially better performance and lower
memory consumption than the present gravity solver in ENZO. In simulations that
include adiabatic gas dynamics, we find general agreement in the distribution
functions of temperature, entropy, and density for gas of moderate to high
overdensity, as found inside dark matter halos. However, there are some
significant differences at lower overdensities. We argue that these
discrepancies are presumably owing to differences in the shock-capturing
abilities of the different methods. In particular, ZEUS hydro leads to some
unphysical heating at early times in preshock regions. Overall, the GADGET
hydro results are bracketed by those for ENZO/ZEUS and ENZO/PPM. (abridged)


title:
Photometric Observations of an SU UMa-type Dwarf Nova VW Coronae
  Borealis during Outbursts

abstract:
  We report the photometric observations of an SU UMa-type dwarf nova VW CrB
during two superoutbursts in 2001 and 2003 and a normal outburst in 2003.
Superhumps with a period of 0.07287(1) d were observed during the 2003
superoutburst. The change rate of the superhump period was positive. During the
normal outburst, there are some hint of modulation up to a 0.2-mag amplitude.
However, any periodicity was not found. The recurrence cycles of the normal
outburst and the superoutburst, and the distance were estimated to be > ~50 d,
270-500 d, and 690(+230, -170) pc, respectively. These recurrence cycles are
usual values for an SU UMa-type dwarf nova having this superhump period. The
superhump period of VW CrB was the longest among those of the SU UMa stars with
positive derivatives of the superhump period. The coverage of our observations
was, however, not enough, and the variation of the Psh change rate of VW CrB is
still unknown. A superhump regrowth and a brightening were seen near the end of
the plateau phase. Measuring the deviation of the start timings of the
brightening and the superhump regrowth (>2 days in VW CrB) will be a key to
reveal the mechanism of these phenomena.


title: The Reionization History in the Lognormal Model

abstract:
  We study the evolution of baryonic gas before the reionization in the
lognormal (LN) model of cosmic clustering. We show that the thermal history of
the universe around the reionization can roughly be divided into three epochs:
1) cold dark age $z>z_r$, in which baryon gas is neutral, and opaque to
Ly$\alpha$ photons; 2) hot dark age $z_r > z> z_{gp}$, in which a predominant
part of baryon gas is ionized and hot, but it is still opaque to Ly$\alpha$
photons; 3) bright age $z<z_{gp}$, in which the universe is ionized highly
enough to be transparent to Ly$\alpha$ photons. In the flat cold dark matter
cosmological models given by WMAP and COBE, the difference of the two redshifts
$z_r - z_{gp}$ is found to be as large as $\sim 10$ with $z_r\sim 17$ and
$z_{gp}\sim 7$. This reionization history naturally yields a high optical depth
to the CMB $\tau_e \simeq 0.12 - 0.19$ observed by the TE polarization of the
WMAP, and a low redshift $z_{gp}$ of the appearance of the Ly$\alpha$
Gunn-Peterson trough $z_{gp} \simeq 6 - 8$ in QSO's absorption spectra. The
reason why the universe stays long in an ionized, yet Ly$\alpha$ opaque, stage
is because the first photo-ionization heats the intergalactic gas effectively
and has balanced the gravitational clustering a long period of time. Therefore,
the result of a high $\tau_e$ and low $z_{gp}$ is a common feature of all the
models considered. Besides the cosmological parameters, the only free parameter
we used in the calculation is $N_{ion}$, the mean ionization photons produced
by each baryon in collapsed objects. We take it to be 40 - 80 in the
calculation.


title: The unusual emission line spectrum of IZw1

abstract:
  Most Seyfert 1s show strong Fe II lines in their spectrum having the velocity
and width of the broad emission lines. To remove the Fe II contribution in
these objects, an accurate template is necessary. We used very high
signal-to-noise, medium resolution archive optical spectra of I Zw 1 to build
such a template.
  I Zw 1 is a bright narrow-line Seyfert 1 galaxy. As such it is well suited
for a detailed analysis of its emission line spectrum. Furthermore it is known
to have a very peculiar spectrum with, in addition to the usual broad and
narrow line regions, two emission regions emitting broad and blue shifted [O
III] lines making it a peculiarly interesting object. While analysing the
spectra, we found that the narrow-line region is, unlike the NLR of most
Seyfert 1 galaxies, a very low excitation region dominated by both permitted
and forbidden Fe II lines. It is very similar to the emission spectrum of a
blob in $\eta$ Carinae which is a low temperature (T$_{\rm e}\sim$6 500 K),
relatively high density (N$_{\it e}$=10$^{6}$ cm$^{-3}$) cloud. The Fe II lines
in this cloud are mainly due to pumping via the stellar continuum radiation
field (Verner et al. \cite{verner02}). We did not succeed in modelling the
spectrum of the broad-line region, and we suggest that a non radiative heating
mechanism increases the temperature in the excited H I region, thus providing
the necessary additional excitation of the Fe II lines. For the low-excitation
narrow-line region, we are able to settle boundaries to the physical conditions
accounting for the forbidden and permitted Fe II lines (10$^{6}$$<$N$_{\rm
e}$$<10^{7}$ cm$^{-3}$; 10$^{-6}$$<$U$<10^{-5}$).


title: The Concordance Model - a Heuristic Approach from a Stationary Universe

abstract:
  Given there has been something where a big-bang origin of our evolutionary
cosmos took place: What is the relativistic line element describing the energy
density and pressure of such a pre-existing universal background? The simplest
conceivable ansatz leads to a Stationary-Universe Model (SUM), which instead of
the 'Steady-state Theory' is shown to be an arguable alternative to the
Cosmological Concordance Model (CCM) commonly accepted today. The SUM stands
out with redshift values statistically independent of time; a significant
Hubble parameter is proved in contrast to the conventional one. It requires a
negative gravitational 'dark' pressure of -1/3 the critical density. Intrinsic
limitations of proper length and time are derived, which cause a struggle of
local SRT (quantum mechanics) and universal GRT (gravitation). Using one
macroscopic constant H in addition to c and G only, the model describes a
background free of coincidences or horizon problems. While the CCM's key
parameter Omega_Lambda seems determined by SUM 'boundary' conditions, there is
a chance of having already observed parts of a stationary universe: With no
need for 'dark energy', this alternative explains straightforwardly the SNe-Ia
data on universal scales. In addition to its currently assumed parts, a
non-lensing homogeneous background of matter might fill the gap to critical
density. A mathematical solution for a perfect black-body spectrum composed of
redshifted microwave radiation emitted from 'dark' sources within the universe
is derived; thus the CMB might exist as a special part of the extragalactic
background light. Given the law of entropy restricted to evolutionary
processes, an open concept is revealed to imply a 'chaotic' quasi-inflation
background, embedding 'local-bang' cosmoses therein. - The SUM is shown to be
the only arguable solution of Einstein's original equations without
cosmological constant.


title:
Keck IR Spectroscopy of WZ Sge: Detection of Molecular Emission from the
  Accretion Disk

abstract:
  Time-resolved IR spectroscopy of WZ Sge was obtained using NIRSPEC on Keck
II. We detect CO and H$_{\rm 2}$ emission from the accretion disk placing WZ
Sge into a rarefied class of astronomical objects including YSOs and high
luminosity early-type stars. During the eclipse phase, the molecular emission
greatly weakens but no firm evidence for the secondary star is seen allowing
new limits on its luminosity to be determined. The detection of molecular
emission provides physical properties within the outer disk of T=3000K and
N$_H$$>10^{10}$ cm$^{-3}$. Such a cool, dense region, not associated with areas
of H I and He I emission, provides the first observational confirmation of
predictions made by accretion disk models.


title:
HST/ACS Imaging of Omega Centauri: Optical Counterpart for the Quiescent
  Low-Mass X-Ray Binary

abstract:
  We report the discovery of an optical counterpart to a quiescent neutron star
in the globular cluster Omega Centauri (NGC 5139). The star was found as part
of our wide-field imaging study of Omega Cen using the Advanced Camera for
Surveys (ACS) on Hubble Space Telescope. Its magnitude and color (R_625 = 25.2,
B_435 - R_625 = 1.5) place it more than 1.5 magnitudes to the blue side of the
main sequence. Through an H-alpha filter it is ~ 1.3 magnitudes brighter than
cluster stars of comparable M_625 magnitude. The blue color and H-alpha excess
suggest the presence of an accretion disk, implying that the neutron star is
accreting from a binary companion and is thus a quiescent low-mass X-ray
binary. If the companion is a main-sequence star, then the faint absolute
magnitude (M_625 ~ 11.6) constrains it to be of very low mass (M <~ 0.14
Msolar). The faintness of the disk (M_435 ~ 13) suggests a very low rate of
accretion onto the neutron star. We also detect 13 probable white dwarfs and
three possible BY Draconis stars in the 20" x 20" region analyzed here,
suggesting that a large number of white dwarfs and active binaries will be
observable in the full ACS study.