title: What does inflation really predict?

abstract:
  If the inflaton potential has multiple minima, as may be expected in, e.g.,
the string theory "landscape", inflation predicts a probability distribution
for the cosmological parameters describing spatial curvature (Omega_tot), dark
energy (rho_Lambda, w, etc.), the primordial density fluctuations (Omega_tot,
dark energy (rho_Lambda, w, etc.). We compute this multivariate probability
distribution for various classes of single-field slow-roll models, exploring
its dependence on the characteristic inflationary energy scales, the shape of
the potential V and and the choice of measure underlying the calculation. We
find that unless the characteristic scale Delta-phi on which V varies happens
to be near the Planck scale, the only aspect of V that matters observationally
is the statistical distribution of its peaks and troughs. For all energy scales
and plausible measures considered, we obtain the predictions Omega_tot ~
1+-0.00001, w=-1 and rho_Lambda in the observed ballpark but uncomfortably
high. The high energy limit predicts n_s ~ 0.96, dn_s/dlnk ~ -0.0006, r ~ 0.15
and n_t ~ -0.02, consistent with observational data and indistinguishable from
eternal phi^2-inflation. The low-energy limit predicts 5 parameters but prefers
larger Q and redder n_s than observed. We discuss the coolness problem, the
smoothness problem and the pothole paradox, which severely limit the viable
class of models and measures. Our findings bode well for detecting an
inflationary gravitational wave signature with future CMB polarization
experiments, with the arguably best-motivated single-field models favoring the
detectable level r ~ 0.03. (Abridged)


title: Constraints on relativistic beaming from estimators of the unbeamed flux

abstract:
  We review the statistical properties of relativistic Doppler boosting
relevant for studies of relativistic jets from compact objects based on
radio--X-ray(--mass) correlations, such as that found in black-hole X-ray
binaries in the low/hard state, or the ``fundamental plane'' of Merloni, Heinz,
& DiMatteo. We show that the presence of only moderate scatter in such
relations does not necessarily imply low Lorentz factors of the jets producing
the radio emission in the samples under consideration. Applying Doppler beaming
statistics to a large sample of XRBs and AGN, we derive a limit on the width of
the Lorentz factor distribution of black holes with relativistic jets: If the
X-rays are unbeamed (e.g., if they originate in the accretion disk or in the
slower, innermost part of the jet), the width of the \beta\Gamma distribution
should be about one order of magnitude or less. If the scatter about the
``fundamental plane'' is entirely dominated by relativistic beaming, a lower
limit on the mean Lorentz factor <\beta\Gamma> > 5 can be derived. On the other
hand, if the X-rays are boosted by the same factor as the radio emission, we
show that the observed scatter cannot be reasonably explained by Doppler
boosting alone.


title:
Dynamical Decoupling of Nested Bars: Self-Gravitating Gaseous Nuclear
  Bars

abstract:
  A substantial fraction of barred galaxies host additional nuclear bars which
tumble with pattern speeds exceeding those of the large-scale (primary) stellar
bars. We have investigated the mechanism of formation and dynamical decoupling
in such nested bars which include gaseous (secondary) nuclear bars within the
full size galactic disks, hosting a double inner Lindblad resonance. Becoming
increasingly massive and self-gravitating, the nuclear bars lose internal
(circulation) angular momentum to the primary bars and increase their strength.
Developing chaos within these bars triggers a rapid gas collapse -- bar
contraction. During this time period, the secondary bar pattern speed
Omega_s~a^{-1}, where "a" stands for the bar size. As a result, Omega_s
increases dramatically until a new equilibrium is reached (if at all), while
the gas specific angular momentum decreases -- demonstrating the dynamical
decoupling of nested bars. Viscosity, and therefore the gas presence, appears
to be a necessary condition for the prograde decoupling of nested bars. This
process maintains an inflow rate of ~1 M_o/yr over ~10^8 yrs across the central
200 pc and has important implications for fueling the nuclear starbursts and
AGN.


title: Testing General Relativity on the Scales of Cosmology

abstract:
  The cosmological tests are tight enough now to show that the
Friedmann-Lemaitre Lambda CDM cosmological model almost certainly is a useful
approximation. This means general relativity theory passes significant tests of
the extrapolation of some fifteen orders of magnitude from the length scales of
the precision tests of gravity physics.


title:
Magnetohydrodynamic Simulations of Shock Interactions with Radiative
  Clouds

abstract:
  We present results from two-dimensional numerical simulations of the
interactions between magnetized shocks and radiative clouds. Our primary goal
is to characterize the dynamical evolution of the shocked clouds. We perform
runs in both the strong and weak magnetic field limits and consider three
different field orientations. For the geometries considered, we generally find
that magnetic fields external to, but concentrated near, the surface of the
cloud suppress the growth of destructive hydrodynamic instabilities. External
fields also increase the compression of the cloud by effectively acting as a
confinement mechanism driven by the interstellar flow and local field
stretching. This can have a dramatic effect on both the efficiency of radiative
cooling, which tends to increase with increasing magnetic field strength, and
on the size and distribution of condensed cooled fragments. In contrast, fields
acting predominately internally to the cloud tend to resist compression,
thereby inhibiting cooling. We observe that, even at modest strengths, internal
fields can completely suppress low-temperature cooling.


title: Disentangling Composite Spectrum Hot Subdwarfs

abstract:
  We give preliminary results from a spectroscopic study of composite spectrum
hot subdwarfs (sd+late-type). We obtained spectra of a sample of hot subdwarfs
selected from the "Catalogue of Spectroscopically Identified Hot Subdwarfs" on
the basis of near-infrared photometry from the Two Micron All Sky Survey
(2MASS). The sample consists of 20 photometric and spectroscopic single and 54
composite hot subdwarfs, 6 resolved (or barely resolved) visual doubles, and 5
objects with emission lines or broad absorption lines with emission cores.
Spectra of 84 "standard" (single late-type) stars with Hipparcos parallaxes
were also obtained for calibration. These observations cover 4600-8900 Ang with
3 Ang resolution. We measured equivalent width-like indices around Mg I b, Na I
D, the Ca II infrared triplet, H-alpha, and H-beta. Using the single late-type
star observations combined with model energy distributions, we explore how the
measured indices of a composite spectrum vary as the temperature and luminosity
of the late-type companion are varied and as the temperature and radius of the
hot subdwarf are varied. We use the measured indices of the composite systems
to estimate the temperature and gravity of the late-type star, taking into
account the dilution of its spectral features by light from the hot subdwarf.


title: How Many Hot Subdwarf Stars Were Rejected from the PG Survey?

abstract:
  The Palomar-Green (PG) survey for UV-excess objects selected objects with
U-B<-0.46 for spectroscopic follow-up. The color selection was done from
photographic photometry, with typical error sigma_(U-B)=0.38. Spectroscopic
detection of the Ca II K line in color-selected candidates was thought to
indicate that a metal-weak cool star (sdF-sdG) had entered the list owing to
photometric errors. About 1100 such "K-line" stars were rejected on this basis
from the final published PG catalogue, as not having "genuine" UV excesses.
However, another possibility is that some of these objects are composite
(binary) stars, consisting of a hot subdwarf (sdB or sdO) and a cool companion
(F-G-K).
  Recent interest in binary-star formation channels for sdB stars in particular
has brought renewed attention to the issue of completeness of lists of known
hot subdwarfs, especially ones with cool companions. We have studied the nature
of the "rejected" PG candidate stars, by assembling available information for a
subset of 173 stars between r magnitudes 14.0 and 16.0 that have photometric
data from both Data Release 2 of the Sloan Digital Sky Survey (SDSS) and the
Two-Micron All Sky Survey (2MASS). Two of the stars have SDSS spectra. Both
from their location in (u-g,g-r) and (g-r,r-K_s) two-color diagrams and from
detailed fitting of single-star models to the spectral energy distributions, we
conclude that the vast majority of these stars can be interpreted as metal-poor
F and G subdwarfs, consistent with the original interpretation by the authors
of the PG survey. We discuss the seven outliers individually; these may
plausibly be binary systems that include a hot subdwarf star as a member, or
they are hot stars that entered the list of rejected stars by accident.


title: Probing Halos of Galaxies at Very Large Radii using Background QSOs

abstract:
  (ABRIDGED) Gaseous halos of nine nearby galaxies (with redshifts cz < 6000
km/s) were probed at large galactocentric radii using background quasars
observed with HST GHRS and STIS. The projected quasar-galaxy separations range
from 55 to 387 h^{-1}_{75} kpc. Ly\alpha absorption lines were successfully
detected in the spectra of five quasars, at impact parameters of up to 170
h^{-1}_{75} kpc from the center of the nearby galaxy, and in each case at
wavelengths consistent with the galaxy's redshift. Our observations include the
lowest redshift Ly\alpha lines detected to date. HI velocity fields were
obtained at the VLA for three of the galaxies in our sample (and in one case
was available from the literature), to derive their rotation curves. When
comparing the inner rotation curves of the galaxies with the velocity at large
radius provided by the Ly\alpha line it is apparent that it is very difficult
to explain the observed Ly\alpha velocity as due to gas in an extended rotating
disk. In most cases one would need to invoke large warps in the outer gas disks
and also thick gas disks in order to reconcile the observed velocities with the
predicted ones. In light of these results we conclude that in a typical galaxy
there is no longer detectable atomic gas corotating in an extended disk at
radii > 35 \alpha ^{-1}, where \alpha^{-1} is the stellar disk exponential
scale-length. The cosmic web is the most likely origin for the detected
Ly\alpha lines.


title: Effects of a deformation of a star on the gravitational lensing

abstract:
  We study analytically a gravitational lens due to a deformed star, which is
modeled by using a monopole and a quadrupole moment. Positions of the images
are discussed for a source on the principal axis. We present explicit
expressions for the lens equation for this gravitational lens as a single real
tenth-order algebraic equation. Furthermore, we compute an expression for the
caustics as a discriminant for the polynomial. Another simple parametric
representation of the caustics is also presented in a more tractable form. A
simple expression for the critical curves is obtained to clarify a topological
feature of the critical curves; the curves are simply connected if and only if
the distortion is sufficiently large.


title: Baby supernovae through the looking glass at long wavelengths

abstract:
  We emphasize the importance of observations of young supernovae in wide radio
band. We argue on the basis of observational results that only high or only low
frequency data is not sufficient to get full physical picture of the shocked
plasma. In the SN 1993J composite spectrum obtained with Very Large Array (VLA)
and Giant Metrewave Radio Telescope (GMRT), around day 3200, we see
observational evidence of synchrotron cooling, which leads us to the direct
determination of the magnetic field independent of the equipartition
assumption, as well as the relative strengths of the magnetic field and
relativistic particles energy densities. The GMRT low frequency SN 1993J light
curves suggests the modification in the radio emission models developed on the
basis of VLA data alone. The composite radio spectrum of SN 2003bg on day 350
obtained with GMRT plus VLA strongly supports the internal synchrotron self
absorption as the dominant absorption mechanism.


title: Implications of aging in young supernovae

abstract:
  We present here the combined radio spectrum from the Giant Metrewave Radio
Telescope (GMRT) and Very Large Array (VLA) of type-IIb SN 1993J (age 11 years)
and a type-Ic SN 2003bg (age 1 year). In SN 1993J, we find a break in the
spectrum at 4 GHz and associate it with Synchrotron cooling break. Hence, we
determine the magnetic field independent of equipartition assumption between
relativistic electrons and magnetic energy. We also see a hint of break in the
spectrum of SN 2003bg between 22-40 GHz. The spectrum of SN 2003bg is well
described by the synchrotron self absorption model.


title:
Time-Resolved Ultraviolet Spectroscopy of the SW Sex Star DW UMa:
  Confirmation of a Hidden White Dwarf and the UV Counterpart to Phase 0.5
  Absorption Events

abstract:
  We present time-resolved, ultraviolet (UV) spectroscopy of the SW Sex star DW
UMa in the high state. We confirm that, shortward of 1500 \AA, the high-state,
UV continuum level is lower than the white dwarf (WD)-dominated low-state
level. We also do not see the WD contact phases in the high state eclipse light
curves. These results confirm our earlier finding that the WD in this system is
hidden from view in the high state. Based on this, we caution that eclipse
mapping of high-inclination SW Sex stars in the high state may yield incorrect
or misleading results. In the context of DW UMa, we demonstrate explicitly that
distance estimates obtained by recent eclipse mapping studies cannot be
reconciled with the WD-dominated low-state spectrum. We also show that the
fluxes of the UV emission lines in the high state drop near orbital phase 0.5.
This is the first detection of a UV counterpart to the class-defining phase 0.5
absorption seen in the optical emission lines of SW Sex stars.


title: XMM-{\em Newton} Observations of Optically Selected SDSS Clusters

abstract:
  We explore the X-ray properties of a subset of the optically selected SDSS
cluster sample of Goto et al. (2002), by analysing seven public XMM-{\em
Newton} pointings, with exposure times ranging from $\sim$ 4 to 46 ksec. There
are in total 17 SDSS clusters out of which only eight are detected at X-ray
wavelengths with $\rm f_{0.5-2keV}\magcir 1.2 \times 10^{-14}$ ergs cm$^{-2}$
s$^{-1}$. For the remaining 9 SDSS clusters we estimate their 3$\sigma$
luminosity upper limits (corresponding to $L_x\mincir 5\times 10^{42}$ ergs/sec
in the 0.5-2 keV band). This relatively low luminosity suggests that if real
structures, these galaxy aggregations correspond to poor groups of galaxies.
Using the SDSS photometric catalogue we also derive the cluster optical
$r$-band luminosities. The resulting scaling relations ($L_{\rm opt}-L_x$,
$L_{\rm opt}-T_x$) are consistent with those of other recent studies.


title: New low-frequency nonlinear electromagnetic wave in a magnetized plasma

abstract:
  A new nonlinear electromagnetic wave mode in a magnetized plasma is
predicted. Its existence depends on the interaction of an intense circularly
polarized electromagnetic wave with a plasma, where quantum electrodynamical
photon--photon scattering is taken into account. This scattering gives rise to
a new coupling between the matter and the radiation. Specifically, we consider
an electron--positron plasma, and show that the propagation of the new mode is
admitted. It could be of significance in pulsar magnetospheres, and result in
energy transport between the pulsar poles.


title:
Steeper, Flatter, or Just "Salpeter"? Evidence from Galaxy Evolution and
  Galaxy Clusters

abstract:
  A single-slope "Salpeter" IMF overpredicts the stellar M/L ratio of local
elliptical galaxies by about a factor of 2, which requires the IMF to be
flatter below about one solar mass. On the other hand a Salpeter IMF for stars
more massive than the sun predicts an evolution with redshift of the
fundamental plane of ellipticals in clusters which is in agreement with the
observations and a formation at z>~3 for these galaxies. A "Salpeter" IMF for
1<M<40 solar masses also predicts the observed amount of heavy elements (oxygen
and silicon) in clusters of galaxies.


title:
Constraints on AGB models from the heavy-element composition of presolar
  SiC grains

abstract:
  Presolar SiC grains formed around Asymptotic Giant Branch (AGB) stars during
their carbon-rich phase and contain heavy elements in trace amounts showing the
signature of the slow neutron capture process (s process). Thanks to recent
advances in analysis techniques, SiC data now provide extremely precise
information on neutron capture cross sections and AGB models. For example,
high-precision data for Mo in single SiC grains indicate that a revision of the
95Mo neutron capture cross section is needed, while data for Zr indicates that
the 22Ne(alpha,n)25Mg reaction cannot be a dominant neutron source for the s
process in AGB stars. We present model predictions for the composition of
Fe-peak elements in AGB stars. These elements could be analysed in the near
future thus providing further stringent constraints to our understanding of AGB
stars.


title: Multiwavelength evidence of the physical processes in radio jets

abstract:
  Over the last few years, high-quality X-ray imaging and spectroscopic data
from Chandra and XMM-Newton have added greatly to the understanding of the
physics of radio jets. Here we describe the current state of knowledge with an
emphasis on the underlying physics used to interpret multiwavelength data in
terms of physical parameters.


title:
Three-dimensional Continuum Radiative Transfer Images of a Molecular
  Cloud Core Evolution

abstract:
  We analyze a three-dimensional smoothed particle hydrodynamics simulation of
an evolving and later collapsing pre-stellar core. Using a three-dimensional
continuum radiative transfer program, we generate images at 7 micron, 15
micron, 175 micron, and 1.3 mm for different evolutionary times and viewing
angles. We discuss the observability of the properties of pre-stellar cores for
the different wavelengths. For examples of non-symmetric fragments, it is shown
that, misleadingly, the density profiles derived from a one-dimensional
analysis of the corresponding images are consistent with one-dimensional core
evolution models. We conclude that one-dimensional modeling based on column
density interpretation of images does not produce reliable structural
information and that multidimensional modeling is required.


title: Cen A and its interaction with the x-ray emitting interstellar medium

abstract:
  As the closest radio galaxy, Centaurus A is a powerful laboratory for the
X-ray study of radio-emitting structures and their interactions with the hot
interstellar medium (ISM). This paper details our interpretation of the
remarkable X-ray enhancement which caps the inner southwest radio lobe, at a
radius of about 6 kpc from the galaxy center. The shell of X-ray-emitting gas
is hotter than the ambient ISM, and overpressured by a factor of 100. We argue
that it is heated compressed material behind the supersonically-advancing bow
shock of the radio lobe, the first example of the phenomenon to be clearly
detected. The results demonstrate that Cen A is actively re-heating nearby
X-ray-emitting gas. The shell's kinetic energy is $\sim 5$ times its thermal
energy, and exceeds the thermal energy of the ISM within 15 kpc of the center
of the galaxy. As the shell dissipates it will have a major effect on Cen A's
ISM, providing distributed heating.


title:
NGC 6404 and NGC 6583: two neglected intermediate-age open clusters
  located in the Galactic Center direction

abstract:
  We report on $VI$ CCD photometry of two fields centered in the region of the
open clusters NGC 6404 and NGC 6583 down to $V=22.0$. These clusters have never
been studied insofar, and we provide for the first time estimates of their
fundamental parameters, namely, radial extent, age, distance and reddening. We
find that NGC 6404 radius is 2.0 arcmin, as previously proposed, while NGC 6583
radius is 1.0 arcmin, significantly lower than previous estimates. Both
clusters turn out to be of intermediate age (0.5-1.0 Gyr old), and located
inside the solar ring, at a Galactocentric distance of about 6.5 kpc. These
results make these objects very interesting targets for spectroscopic follow-up
to measure their metallicity. In fact they might allow us to enlarge by more
than 1 kpc the baseline of the radial abundance gradient in the Galactic disk
toward the Galactic Center direction. This baseline is currently rather narrow
especially for clusters of this age.


title:
Reconstructing the evolution of white dwarf binaries: further evidence
  for an alternative algorithm for the outcome of the common-envelope phase in
  close binaries

abstract:
  We determine the possible masses and radii of the progenitors of white dwarfs
in binaries from fits to detailed stellar evolution models and use these to
reconstruct the mass-transfer phase in which the white dwarf was formed. We
confirm the earlier finding that in the first phase of mass transfer in the
binary evolution leading to a close pair of white dwarfs, the standard
common-envelope formalism equating the energy balance in the system, does not
work. An algorithm equating the angular momentum balance can explain the
observations. This conclusion is now based on ten observed systems rather than
three. With the latter algorithm the separation does not change much for
approximately equal mass binaries. Assuming constant efficiency in the standard
\alpha-formalism and a constant value of \gamma, we investigate the effect of
both methods on the change in separation in general and conclude that when
there is observational evidence for strong shrinkage of the orbit, the
\gamma-algorithm also leads to this. We then extend our analysis to all close
binaries with at least one white dwarf component and reconstruct the mass
transfer phases that lead to these binaries. We find that all observations can
be explained with a single value of \gamma, making the \gamma-algorithm a
useful tool to predict the outcome of common-envelope evolution. We discuss the
consequences of our findings for different binary populations in the Galaxy,
including massive binaries, for which the reconstruction method cannot be used
(abbriged).


title:
Multifrequency Observations of the Gamma-Ray Blazar 3C 279 in Low-State
  during Integral AO-1

abstract:
  We report first results of a multifrequency campaign from radio to hard X-ray
energies of the prominent gamma-ray blazar 3C 279 during the first year of the
INTEGRAL mission. The variable blazar was found at a low activity level, but
was detected by all participating instruments. Subsequently a multifrequency
spectrum could be compiled. The individual measurements as well as the compiled
multifrequency spectrum are presented. In addition, this 2003 broadband
spectrum is compared to one measured in 1999 during a high activity period of
3C 279.


title:
Mass-loss and multicomponent flow from central stars of planetary
  nebulae

abstract:
  We calculate multicomponent radiatively driven stellar wind models suitable
for central stars of planetary nebulae. Some of these stellar winds may be
adequately modelled using one-component models, however for some of them
multicomponent models are necessary. We obtain a range of stellar parameters
for different types of mass-loss.


title:
Gamma-rays from cascades in close massive binaries containing energetic
  pulsars

abstract:
  Some massive binaries should contain energetic pulsars which inject
relativistic leptons from their inner magnetospheres and/or pulsar wind
regions. If the binary system is compact enough, then these leptons can
initiate inverse Compton (IC) $e^\pm$ pair cascades in the anisotropic
radiation field of a massive star. $\gamma$-rays can be produced in the IC
cascade during its development in a pulsar wind region and above a shock in a
massive star wind region where the propagation of leptons is determined by the
structure of a magnetic field around the massive star. For a binary system with
specific parametres, we calculate phase dependent spectra and fluxes of
$\gamma$-rays escaping as a function of the inclination angle of the system and
for different assumptions on injection conditions of the primary leptons (their
initial spectra and location of the shock inside the binary). We conclude that
the features of $\gamma$-ray emission from such massive binaries containing
energetic pulsars should allow to obtain important information on the
acceleration of particles by the pulsars, and on interactions of a compact
object with the massive star wind. Predicted $\gamma$-ray light curves and
spectra in the GeV and TeV energy ranges from such binary systems within our
Galaxy and Magellanic Clouds should be observed by future AGILE and GLAST
satellites and low threshold Cherenkov telescopes such as MAGIC, HESS, VERITAS
or CANGAROO III.


title:
A Chandra Snapshot Survey of IR-bright LINERs: A Possible Link Between
  Star Formation, AGN Fueling, and Mass Accretion

abstract:
  We present results from a high resolution X-ray imaging study of nearby
LINERs observed by Chandra. This study complements and extends previous X-ray
studies of LINERs, focusing on the under-explored population of nearby
dust-enshrouded infrared-bright LINERs. The sample consists of 15 IR-bright
LINERs (L_FIR/L_B > 3), with distances that range from 11 to 26 Mpc. Combining
our sample with previous Chandra studies we find that ~ 51% (28/55) of the
LINERs display compact hard X-ray cores. The nuclear 2-10 keV luminosities of
the galaxies in this expanded sample range from ~ 2 X 10^38 ergs s^-1 to ~ 2 X
10^44 ergs s^-1. We find an intriguing trend in the Eddington ratio vs. L_FIR
and L_FIR/L_B for the AGN-LINERs in the expanded sample that extends over seven
orders of magnitude in L/L_Edd. This correlation may imply a link between black
hole growth, as measured by the Eddington ratio, and the star formation rate
(SFR), as measured by the far-IR luminosity and IR-brightness ratio. If the
far-IR luminosity is an indicator of the molecular gas content in our sample of
LINERs, our results may further indicate that the mass accretion rate scales
with the host galaxy's fuel supply. We discuss the potential implications of
our results in the framework of black hole growth and AGN fueling in low
luminosity AGN. (Abridged)


title: A search for the first massive galaxy clusters

abstract:
  We have obtained deep, multi-band imaging observations around three of the
most distant known quasars at redshifts z>6. Standard accretion theory predicts
that the supermassive black holes present in these quasars were formed at a
very early epoch. If a correlation between black hole mass and dark matter halo
mass is present at these early times, then these rare supermassive black holes
will be located inside the most massive dark matter halos. These are therefore
ideal locations to search for the first clusters of galaxies. We use the
Lyman-break technique to identify star-forming galaxies at high redshifts. Our
observations show no overdensity of star-forming galaxies in the fields of
these quasars. The lack of (dust-free) luminous starburst companions indicates
that the quasars may be the only massive galaxies in their vicinity undergoing
a period of intense activity.


title: Detection of anti-correlated hard X-ray time lag in Cygnus X-3

abstract:
  The wide-band X-ray spectra of the high mass X-ray binary Cygnus X-3 exhibits
a pivoting behavior in the `low' (as well as `hard') state, correlated to the
radio emission. The time scale of the soft and hard X-rays' anti-correlation,
which gave rise to the pivoting feature, was found to be less than a day from
the monitoring observations by RXTE--ASM and CGRO--BATSE. In this Letter we
report the detection of a lag of $\lesssim$ 1000s in the anti-correlation of
the hard X-ray emission (20--50 keV) to that of the soft X-ray emission (2--7
keV), which may be attributed to the viscous time scale of flow of matter in
the accretion disk. This suggests the geometrical picture of a truncated
accretion disc with a Compton cloud inside the disc, the relative sizes of
which determine the spectral shape. Any change in the disc structure will take
place in a viscous time scale, with corresponding anti-correlated change in the
Compton cloud. We also report the pivoting in the spectra in one span of a
pointed observation when an episode of the rearranging of the accretion system
is serendipitously observed. This is the first such observation of hard X-ray
delay seen in the persistent Galactic microquasars, within the precincts of the
hard state.


title: A Virgo high-resolution Halpha kinematical survey

abstract:
  We have completed a survey of 30 Virgo cluster galaxies in the Halpha
emission-line using Fabry-Perot interferometry. The goal of the survey is to
obtain a high angular resolution sample of velocity fields of spirals and to
study the environmental effects on their kinematics and dynamics.


title: The Fate of Bound Systems in Phantom and Quintessence Cosmologies

abstract:
  We study analytically and numerically the evolution of bound systems in
universes with accelerating expansion where the acceleration either increases
with time towards a Big Rip singularity (phantom cosmologies) or decreases with
time (quintessence). We confirm the finding of Caldwell et. al.
[arXiv:astro-ph/0302506] (hereafter CKW) that bound structures get dissociated
in phantom cosmologies but we demonstrate that this happens earlier than
anticipated by CKW. In particular we find that the `rip time' when a bound
system gets unbounded is not the time when the repulsive phantom energy
gravitational potential due to the average $(\rho + 3p)$ balances the
attractive gravitational potential of the mass M of the system. Instead, the
`rip time' is the time when the minimum of the time dependent effective
potential (including the centrifugal term) disappears. For the Milky Way galaxy
this happens approximately 180Myrs before the Big Rip singularity instead of
approximately 60Myrs indicated by CKW for a phantom cosmology with w=-1.5. A
numerical reconstruction of the dissociating bound orbits is presented.


title: Can Dust Explain Variations in the D/H Ratio?

abstract:
  The D/H ratio in interstellar gas varies on scales of a few hundred pc in the
local Milky Way, with D/H values ranging from ~7 ppm to ~22 ppm. The reduction
in D/H relative to the primordial value of D/H (~ 26 ppm) is usually attributed
to "astration" -- conversion of D into other elements by nuclear fusion in
stars. However, it is shown here that astration has difficulty accounting for
the observations because the expected associated variations in O/H are not
seen.
  The lower D/H values are instead likely due to "depletion" of the D onto dust
grains. Polycyclic aromatic hydrocarbons (PAHs) are a possible repository for
the missing D, and it appears possible for gas-grain reactions to achieve
extreme deuteration of carbonaceous grain material. Grain destruction will
release D from the grains; the gas phase abundance of D should therefore be
positively correlated with the gas phase abundances of other elements that
exhibit strong depletions, such as Mg, Si, Ti, and Fe, which also will be
returned to the gas by grain destruction.


title:
X-Ray Detection of an Obscured Active Galactic Nucleus in a z=3.09
  Radio-quiet Ly-alpha Nebula

abstract:
  We present evidence for a highly obscured X-ray source in one of two giant
Ly-alpha emission nebulae in the z=3.09 proto-cluster region SSA22. Neither
Ly-alpha nebula is associated with significant radio emission. While one has a
significant submillimeter detection and is undetected in the X-ray, the other
is a factor of 2-10 times less submillimeter bright and appears to contain a
hard-band X-ray source. We discuss our analysis and techniques for assessing
the X-ray properties of this source and suggest that we have detected an
embedded AGN source in one of these nebulae which may be at least partially
responsible for exciting the Ly-alpha emission through a mechanism that is
essentially decoupled from the radio, submillimeter, or optical luminosities.
We also present an upper limit on the mean X-ray emission from 10 other
extended Ly-alpha objects in the SSA22 region.


title:
The Origin and Properties of X-ray-emitting Gas in the Halos of both
  Starburst and Normal Spiral Galaxies

abstract:
  I discuss the empirical properties of diffuse X-ray emitting gas in the halos
of both nearby starburst galaxies and normal spiral galaxies, based on high
resolution X-ray spectral imaging with the Chandra X-ray Observatory. Diffuse
thermal X-ray emission can provide us with unique observational probes of
outflow and accretion processes occurring in star-forming galaxies, and their
interaction with the inter-galactic medium. I consider both the spatial
distribution of the diffuse X-ray emission in and around edge-on starburst
galaxies with superwinds (e.g. surface brightness profiles, distribution with
respect to H-alpha and radio emission), and its spectral properties (e.g.
thermal or non-thermal nature, abundance ratios, temperatures and soft and hard
X-ray luminosities). These results are discussed in the context of current
theoretical models of supernova-driven superwinds, and compared to the more
limited data on extra-planar hot gas around edge-on normal galaxies.


title: Seismology of Accreting White Dwarfs

abstract:
  Pulsation modes have recently been observed in a handful of white dwarf (WD)
primaries of cataclysmic variables, allowing an interesting new probe into the
structure of accreting WD's. We briefly discuss the seismology of these
objects, how stellar properties may be inferred from the observed mode
frequencies, and mode driving mechanisms. For one pulsator, GW Lib, we have
shown that a WD mass $M=1.05 M_\odot$ and accreted envelope mass $M_{\rm
env}=0.4\times 10^{-4} M_\odot$ give the best match to the observed pulsation
periods. A first exploration of mode driving favors $T_{\rm eff} = 14 000 K$
and a massive WD, but more work is necessary.


title: BVI Photometric Variability Survey of M3

abstract:
  We have conducted a three band (BVI) variability survey of the globular
cluster M3. This is the first three band survey of the cluster using modern
image subtraction techniques. Observations were made over 9 nights in 1998 on
the 1.2m telescope at the F.L. Whipple Observatory in Arizona. We present
photometry for 180 variable stars in the M3 field, of which 12 are newly
discovered. New discoveries include six SX Phe type variables which all lie in
the blue straggler region of the color magnitude diagram, two new first
overtone RR Lyrae, a candidate multi-mode RR Lyrae, a detached eclipsing
binary, and two unclassified variables. We also provide revised periods for 52
of the 168 previously known variables that we observe. The catalog and
photometry for the variable stars are available via anonymous ftp at
ftp://cfa-ftp.harvard.edu/pub/kstanek/M3/


title:
On the Importance of Local Sources of Radiation in Cosmological
  Absorption Systems

abstract:
  An upper limit to the importance of local sources of radiation compared to
the cosmic background in cosmological absorption systems is derived, as a
simple consequence of the conservation of surface brightness. The limit depends
only on the rate of incidence of the absorbers and the mean free path of the
radiation. It is found that, on average, the ionizing radiation intensity from
local sources in Lyman limit systems at z>2 must be less than half of the
intensity of the cosmic background. In absorbers with column densities much
lower than Lyman limit systems, the local source contribution must be
negligible. The limit on the ratio of local source to background intensities is
then applied to the class of damped Lya absorption systems with detectable
excited CII lines. A cooling rate of the gas in these systems has been measured
by Wolfe et al., who assumed that the balancing heating source is photoelectric
heating on dust by light at ~ 1500 A . The intensity from local star formation
at this wavelength in this class of damped Lya systems is found to be at most ~
3 times the background intensity. If the heating source is indeed photoelectric
heating of dust, the background created by sources associated with damped Lya
systems can then be estimated from the average cooling rates measured in the
absorbers. Current results yield a background intensity higher than previous
estimates based on observed galaxy and quasar luminosity functions, although
with a large uncertainty. The possibility of other sources of heating, such as
shock-heating in a turbulent medium, should be explored.


title: Evaluating the Magnetic Field Strength in Molecular Clouds

abstract:
  We discuss an extension to the Chandrasekhar-Fermi method for the evaluation
of the mean magnetic field strength in molecular clouds to cases where the
spatial orientation of the field is known. We apply the results to M17, using
previously published data.


title: Diagnostics of Disks Around Hot Stars

abstract:
  We discuss three different observational diagnostics related to disks around
hot stars: absorption line determinations of rotational velocities of Be stars;
polarization diagnostics of circumstellar disks; and X-ray line diagnostics of
one specific magnetized hot star, $\theta^1$ Ori C. Some common themes that
emerge from these studies include (a) the benefits of having a specific
physical model as a framework for interpreting diagnostic data; (b) the
importance of combining several different types of observational diagnostics of
the same objects; and (c) that while there is often the need to reinterpret
traditional diagnostics in light of new theoretical advances, there are many
new and powerful diagnostics that are, or will soon be, available for the study
of disks around hot stars.


title: Chemical compositions of Four B-type Supergiants in the SMC Wing

abstract:
  High-resolution UCLES/AAT spectra of four B-type supergiants in the SMC South
East Wing have been analysed using non-LTE model atmosphere techniques to
determine their atmospheric parameters and chemical compositions. The principle
aim of this analysis was to determine whether the very low metal abundances
($-$1.1 dex compared with Galactic value) previously found in the Magellanic
Inter Cloud region (ICR) were also present in SMC Wing. The chemical
compositions of the four targets are similar to those found in other SMC
objects and appear to be incompatible with those deduced previously for the
ICR. Given the close proximity of the Wing to the ICR, this is difficult to
understand and some possible explanations are briefly discussed.


title:
Microlensing Optical Depth towards the Galactic Bulge Using Clump Giants
  from the MACHO Survey

abstract:
  Using 7 years of MACHO survey data, we present a new determination of the
optical depth to microlensing towards the Galactic bulge. We select the sample
of 62 microlensing events (60 unique) on clump giant sources and perform a
detailed efficiency analysis. We use only the clump giant sources because these
are bright bulge stars and are not as strongly affected by blending as other
events. Using a subsample of 42 clump events concentrated in just 4.5 square
degrees, we find tau = 2.17^{+0.47}_{-0.38} x 10^{-6} at (l,b) = (1.50, -2.68),
somewhat smaller than found in most previous MACHO studies, but in excellent
agreement with recent theoretical predictions. We also present the optical
depth in each of the 19 fields in which we detected events, and find limits on
optical depth for fields with no events. The errors in optical depth in
individual fields are dominated by Poisson noise. We measure optical depth
gradients (1.06 +/- 0.71) x 10^{-6} deg^{-1} and (0.29 +/- 0.43) x 10^{-6}
deg^{-1} in the galactic latitude b and longitude l directions, respectively.
Finally, we discuss the possibility of anomalous duration distribution of
events in the field 104 centered on (l,b) = (3.11, -3.01) as well as
investigate spatial clustering of events in all fields.


title:
Unravelling the Puzzle of the Eclipsing Polar SDSSJ 015543.40+002807.2
  with XMM and Optical Photometry/Spectropolarimetry

abstract:
  The cataclysmic variable SDSSJ 015543.40+002807.2 is confirmed to be a
magnetic system of the AM Herculis type. With an orbital period of 87.13 min,
it is also the shortest-period eclipsing Polar known. Monitoring with
XMM-Newton finds a high-state light curve dominated by a single X-ray emitting
accretion pole located slightly prograde of the secondary star. The hard X-ray
spectrum is typical of radial shocks on magnetic white dwarfs (kT ~ 10keV), and
there is evidence for a soft X-ray component consistent with reprocessing from
the stellar surface. The optical circular polarization is weak (v < 3%) when
the accretion rate is high (mV ~ 15.5), due to optically-thick cyclotron
emission and the apparent competition between two accreting poles. However, in
low states (mV ~ 18), the polarization increases smoothly to the blue, reaching
20% at 4200A, and the flux spectrum displays a rich set of thermally-broadened
cyclotron harmonics that indicate a polar field of 29MG. The phase interval
preceding the 6.5 min eclipse depicts the development of P-Cygni components
followed by complete absorption reversals in the emission lines. This
phenomenon is not unexpected for a strongly accreting magnetic system viewed
through the cool base of the funnel, and high-quality spectroscopy through this
interval will likely lead to new insights into the dynamics of magnetic
coupling and gas flow onto the white dwarf.


title:
The Survey of Nearby Nuclei with STIS (SUNNS):Emission-Line Nuclei at
  Hubble Space Telescope Resolution

abstract:
  We present results from a program of optical spectroscopy for 23 nearby
galaxy emission-line nuclei. This investigation takes advantage of the spatial
resolution of the Hubble Space Telescope to study the structure and energetics
of the central 10 - 20 pc, and the resulting data have value for quantifying
central black hole masses, star formation histories, and nebular properties.
This paper provides a description of the experimental design, and new findings
from the study of emission lines. The sample targets span a range of nebular
spectroscopic class, from HII to Seyfert nuclei. The line ratios indicative of
nebular ionization show only modest variations over order-of-magnitude
differences in radius, and demonstrate in a systematic way that geometrical
dilution of the radiation field from a central source cannot be assumed as a
primary driver of ionization structure. Comparisons between large- and
small-aperture measurements for the HII/LINER transition objects provide a new
test that challenges conventional wisdom concerning the composite nature of
these systems. We also list a number of other quantitative results that are of
interest for understanding galaxy nuclei, including (1) the spatial
distribution/degree of concentration of H-alpha emission as a function of
nebular type; (2) the radial variation in electron density as a function of
nebular type; and (3) quantitative broad H-alpha estimates obtained at a second
epoch for these low-luminosity nuclei. The resulting measurements provide a new
basis for comparing the nuclei of other galaxies with that of the Milky Way. We
find that the Galactic Center is representative across a wide span of
properties as a low-luminosity emission-line nucleus.


title: Microlensing Surveys of M31 in the Wide Field Imaging Era

abstract:
  The Andromeda Galaxy (M31) is the closest large galaxy to the Milky Way, thus
it is an important laboratory for studying massive dark objects in galactic
halos (MACHOs) by gravitational microlensing. Such studies strongly complement
the studies of the Milky Way halo using the the Large and Small Magellanic
Clouds. We consider the possibilities for microlensing surveys of M31 using the
next generation of wide field imaging telescopes with fields of view in the
square degree range. We consider proposals for such imagers both on the ground
and in space. For concreteness, we specialize to the SNAP proposal for a space
telescope and the LSST proposal for a ground based telescope. We find that a
modest space-based survey of 50 visits of one hour each is considerably better
than current ground based surveys covering 5 years. Crucially, systematic
effects can be considerably better controlled with a space telescope because of
both the infrared sensitivity and the angular resolution. To be competitive, 8
meter class wide-field ground based imagers must take exposures of several
hundred seconds with several day cadence.


title: Evolution of Intermediate-Mass Black Hole X-Ray Binaries

abstract:
  The majority of the ultraluminous X-ray sources (ULXs) in external galaxies
are believed to be accreting black holes in binary systems; some of the black
holes could be as massive as $\sim 100-1000 \ms$. We have performed evolution
calculations for intermediate-mass black hole X-ray binaries, assuming they are
formed in dense star clusters via tidal capture. The results are compared with
those for stellar-mass black holes X-ray binaries. We find that these two types
of black holes may have similar companion stars and binary orbits if observed
as ULXs. However, intermediate-mass black holes seem to be favored in
explaining the most luminous ULXs. We also discuss the possibilities of
transient behavior and beamed emission in the evolution of these binary
systems.


title:
About the chemical composition of delta Scuti - the prototype of the
  class of pulsating variables

abstract:
  We present chemical abundances in the photosphere of $\delta$ Scuti -- the
prototype of the class of pulsating variables -- determined from the analysis
of a spectrum obtained at Terskol observatory 2 meter telescope with resolution
$R=52,000$, signal to noise ratio 250. VLT and IUE spectra were used also .
Abundance pattern of \dsct consists of 49 chemical elements. The abundances of
Be, P, Ge, Nb, Mo, Ru, Er, Tb, Dy, Tm, Yb, Lu, Hf, Ta, Os, Pt, Th were not
investigated previously. The lines of third spectra of Pr and Nd also are
investigated for the first time. The abundances of heavy elements show the
overabundances with respect to the Sun up to 1 dex. The abundance pattern of
\dsct is similar to that of Am-Fm stars.


title:
Blue Stragglers in Galactic Open Clusters and the Integrated Spectral
  Energy Distributions

abstract:
  Synthetic integrated spectral properties of the old Galactic open clusters
are studies in this work, where twenty-seven Galactic open clusters of ages >=
1Gyr are selected as the working sample. Based on the photometric observations
of these open clusters, synthetic integrated spectrum has been made for the
stellar population of each cluster. The effects of blue straggler stars (BSSs)
on the conventional simple stellar population (SSP) model are analyzed on an
individual cluster base. It is shown that the BSSs, whose holding positions in
the color-magnitude diagrams (CMDs) cannot be predicted by the current
single-star evolution theory, present significant modifications to the
integrated properties of theoretical SSP model. The synthesized integrated
spectral energy distributions (ISEDs) of our sample clusters are dramatically
different from the SSPs based on isochrone only. The BSSs corrected ISEDs of
stellar populations show systematic enhancements towards shorter wavelength in
the spectra. When measured with wide-band colors in unresolvable conditions,
the age of a stellar population can be seriously under-estimated by the
conventional SSP model. Therefore, considering the common existence of BSS
component in real stellar populations, a considerable amount of alternations on
the conventional ISEDs should be expected when applying the technique of
evolutionary population synthesis (EPS) to more complicated stellar systems.


title:
The environment of Seyferts, Liners and HII galaxies in a Complete AGN
  sample

abstract:
  We use a complete AGN sample (Ho et al. 1997) to study the environment of
Seyferts, LINERs and HII galaxies. For each AGN we search for companions in the
UZC redshift catalogue and compute local as well as large scale neighbour
density and distance to the nearest neighbour. We find that on small scale (~
0.2 h^-1 Mpc) LINERs exhibit denser environments than Seyferts and HII galaxies
at 3 sigma significance level. The same result is not confirmed when densities
are computed on large scales. LINERs also exhibit closer nearest neighbours
than Seyferts and HII galaxies (at 2 sigma c.l.). However, when excluding AGNs
in early type galaxy hosts, the neighbour density characteristics of LINERs
Seyferts and HII galaxies turn out to be similar, a result that confirms that
the excess of neighbours around LINERs is most likely due to a
morphology-density effect.


title:
Collisions Between Single Stars in Dense Clusters: Runaway Formation of
  a Massive Object

abstract:
  Using Monte Carlo codes, we follow the collisional evolution of clusters in a
variety of scenarios. We consider the conditions under which a cluster of main
sequence stars may undergo rapid core collapse due to mass segregation, thus
entering a phase of runaway collisions, forming a very massive star (VMS, M >=
1000 Msun) through repeated collisions between single stars. Although
collisional mass loss is accounted for realistically, we find that a VMS forms
even in proto-galactic nuclei models with a high velocity dispersion (many 100
km/s). Such a VMS may be a progenitor for an intermediate-mass black hole (M >=
100 Msun). In contrast, in galactic nuclei hosting a central massive black
hole, collisions are found to be disruptive. The stars which are subject to
collisions are progressively ground down by high-velocity collisions and a
merger sequence appears impossible.


title: Mass and Angular Momentum of Sgr A*

abstract:
  For very fast spinning black holes with a>0.9953 the orbital velocity of a
test particle unexpectly shows a positive radial gradient for low orbits, an
effect of GR which has been overlooked so far. For a=0.99616 the maximum radial
change of the orbital velocity equals the radial epicyclic frequency, which in
turn is in a 1:3 resonance with the vertical epicyclic frequency. Application
to Sgr A* using the quasi-periodic oscillations recently measured suggest that
the mass of Sgr A* is 3.28 +/- 0.13 million solar masses.


title: Virtual instrumentation to study galaxies

abstract:
  The MIGALE project (http://www.sai.msu.su/migale) provides databases and data
analysis tools to study the evolution of galaxies from z=1 to z=0. It develops
and maintain a general database, HyperLeda, to give a homogenized
parameterization for 3 million objects, and several archives or specialized
databases. It also develops tools to analyse on-the-fly data extracted from the
database or obtained through the Virtual Observatory (Virtual Instruments). The
package made for this project, Pleinpot, is distributed as open source.


title: Magnetorotational supernova simulations

abstract:
  We present 2D results of simulations of the magnetorotational core collapsed
supernova. For the first time we obtain strong explosion for the core collapsed
supernova. In 2D approximation we show that amplification of the toroidal
magnetic field due to the differential rotation leads to the formation of MHD
shockwave, which produces supernova explosion. The amounts of the ejected mass
$0.1M_\odot$ and energy $\sim 0.5\div0.6 \cdot 10^{51}$ergs can explain the
energy output for supernova type II or type Ib/c explosions. The shape of the
explosion is qualitatively depends on the initial configuration of the magnetic
field, and may form strong ejection neat the equatorial plane, or produce
mildly collimated jets. Our simulation show that during the evolution of the
magnetic field the magnetorotational instability appears and leads to
exponential growth of the magnetic field strength.


title: Massive Star Feedback on the IMF

abstract:
  We have obtained the first measures of the mass accretion rates on stars of
the Trapezium Cluster. They appear systematically lower than those of similar
stars in the Taurus-Auriga association. Together with premature disk
evaporation, dramatically revealed by the HST images of the Orion proplyds,
this result suggests that low mass stars in a rich cluster may be ``dwarfed''
by the influence of nearby OB stars. This feedback mechanism affects the IMF,
producing an excess of low mass stars and brown dwarfs. The observed frequency
of low mass objects in Orion vs. Taurus seems to confirm this scenario.


title:
Do the mildly superluminal VLBI knots exclude ultrarelativistic blazar
  jets?

abstract:
  We compute the effective values of apparent transverse velocity and flux
boosting factors for the VLBI radio knots of blazar jets, by integrating over
the angular distributions of these quantities across the widths of jets with
finite opening angles but constant velocities. For high bulk Lorentz factors
(Gamma > 10) variations across the jet can be quite large if the opening angle,
omega, is even a few degrees on sub-parsec scales. The resulting apparent
speeds are often much lower than those obtained from the usual analyses that
ignore the finite jet opening angles. We can thus reconcile the usually
observed subluminal or mildly superluminal speeds with the very high (>~ 20)
Gamma factors, required by the inverse Compton origin and rapid variability of
TeV fluxes, as well as by intraday radio variability. Thus it is possible to
associate the VLBI radio knots directly with shocks in the ultra-relativistic
main jet flow, without invoking very rapid jet deceleration on parsec scales,
or extremely unlikely viewing angles.


title: The X-ray spectrum of NGC 7213 and the Seyfert--LINER connection

abstract:
  We present an XMM-Newton observation of the Seyfert-LINER galaxy NGC 7213.
The RGS soft X-ray spectrum is well fitted with a power law plus soft X-ray
collisionally ionised thermal plasma (kT = 0.18 +0.03/-0.01 keV). We confirm
the presence of Fe I, XXV and XXVI K-alpha emission in the EPIC spectrum and
set tighter constraints on their equivalent widths of 82 +10/-13, 24 +9/-11 and
24 +10/-13 eV respectively. We compare the observed properties together with
the inferred mass accretion rate of NGC 7213, to those of other Seyfert and
LINER galaxies. We find that NGC 7213 has intermediate X-ray spectral
properties lying between those of the weak AGN found in the LINER M81 and
higher luminosity Seyfert galaxies. There appears to be a continuous sequence
of X-ray properties from the Galactic Centre through LINER galaxies to
Seyferts, likely determined by the amount of material available for accretion
in the central regions.


title: Observable Quantities in Cosmological Models with Strings

abstract:
  The Friedman equation for the universe with arbitrary curvature $(k = 0, \pm
1)$, filled with mutually noninteracting pressureless dust, radiation,
cosmological constant, and strings is considered. We assume the string
domination scenario for the evolution of the latter component. Moreover, we
discuss the simplest possibility for the scaling of the string energy density:
$\varrho \propto R^{-2}$. For such models we write down the explicit solution
of the Friedman equation. We realize that corresponding cosmological models do
not essentially differ from those without strings. We find an analytic formula
for the radial coordinate $\chi$ of a galaxy with a redshift z and express it
in terms of astronomical parameters. This relation is then used for the
derivation of the astrophysical formulas such as luminosity distance, angular
diameter, and source counts, which may serve for testing the string-dominated
universe. It seems that the most sensitive test, at least from the formal point
of view, is the formula for the number of galaxies $N(z)$ corresponding to a
given value of the redshift. We show that the maximum of $N(z)$ strongly
depends on the density of strings, especially if the density is large enough to
explain the $\Omega$ problem. Other tests are also proposed.


title: A Rigorous Attempt to Verify Interstellar Glycine

abstract:
  In 2003, Kuan, Charnley, and co-workers reported the detection of
interstellar glycine (NH2CH2COOH) based on observations of 27 lines in 19
different spectral bands in one or more of the sources Sgr B2(N-LMH), Orion KL,
and W51 e1/e2. They supported their detection report with rotational
temperature diagrams for all three sources. In this paper, we present essential
criteria which can be used in a straightforward analysis technique to confirm
the identity of an interstellar asymmetric rotor such as glycine. We use new
laboratory measurements of glycine as a basis for applying this analysis
technique, both to our previously unpublished 12 m telescope data and to the
previously published SEST data of Nummelin and colleagues. We conclude that key
lines necessary for an interstellar glycine identification have not yet been
found. We identify some common molecular candidates that should be examined
further as more likely carriers of several of the lines reported as glycine.
Finally, we illustrate that a rotational temperature diagram used without the
support of correct spectroscopic assignments is not a reliable tool for the
identification of interstellar molecules.


title:
Observational issues in radiometric and interferometric detection and
  analysis of the Sunyaev-Zel'dovich effects

abstract:
  This review discusses the techniques used in single-dish and interferometric
radiometric observations of the Sunyaev-Zel'dovich effects, the pitfalls that
arise, the systematic and other sources of error in the data, and the
uncertainties in the interpretation of the results.


title:
B Star Rotational Velocities in h and chi Persei: A Probe of Initial
  Conditions During the Star-Formation Process

abstract:
  Projected rotational velocities have been measured for 216 B0--B9 stars in
the rich, dense h and chi Persei double cluster, and compared with the
distribution of rotational velocities for a sample of field stars having
comparable ages and masses. For stars that are relatively little evolved from
their initial locations on the Zero Age Main Sequence (3-5 solar masses) the
mean vsini measured for the h and chi Per sample is slightly more than 2 times
larger than the mean determined for field stars of comparable mass, and the
cluster and field vsini distributions differ with a high degree of
significance. For somewhat more evolved stars with masses in the range 5-9
solar masses, the mean vsini in h and chi Per is 1.5 times that of the field;
the vsini distributions differ as well, but with a lower degree of statistical
significance. For stars that have evolved significantly from the ZAMS (those
with masses in the range 9-15 solar masses), the cluster and field star means
and distributions are only slightly different. We argue that both the higher
rotation rates and the pattern of rotation speeds as a function of mass that
differentiate main sequence B stars in h and chi Per from their field analogs
were likely imprinted during the star formation process. We speculate that
these differences may reflect the effects of the higher accretion rates that
theory suggests are characteristic of regions that give birth to dense
clusters, namely: (a) higher initial rotation speeds; (b) higher initial radii
along the stellar birthline, resulting in greater spinup between the birthline
and the ZAMS; and (c) a more pronounced maximum in the birthline radius-mass
relationship that results in differentially greater spinup for stars that
become mid- to late- B stars on the ZAMS.


title:
Double Distribution of Dark Matter Halos with respect to Mass and Local
  Overdensity

abstract:
  We present a double distribution function of dark matter halos, with respect
to both object mass and local over- (or under-) density. This analytical tool
provides a statistical treatment of the properties of matter surrounding
collapsed objects, and can be used to study environmental effects on
hierarchical structure formation. The size of the "local environment" of a
collapsed object is defined to depend on the mass of the object. The
Press-Schechter mass function is recovered by integration of our double
distribution over the density contrast. We also present a detailed treatment of
the evolution of overdensities and underdensities in Einstein-deSitter and flat
LCDM universes, according to the spherical evolution model. We explicitly
distinguish between true and linearly extrapolated overdensities and provide
conversion relations between the two quantities.


title:
A Deep Radio Survey of Abell 2125 I: Radio, Optical and Near-IR
  Observations

abstract:
  We present a description of deep radio, optical, and near IR observations
taken with the VLA, the KPNO 2m and the KPNO 4m of the region containing the
rich cluster of galaxies Abell 2125. The reduction of each dataset is
described. A catalog of radio sources apparently not associated with members of
Abell 2125 and the associated R-band magnitudes is presented.


title:
A Deep Radio Survey of Abell 2125 II: Accelerated Galaxy Evolution
  during a Cluster-Cluster Merger

abstract:
  Using our extensive radio, optical, near-IR and X-ray imaging and
spectroscopy, we consider the reason for the unusually large number of radio
detected galaxies, mostly found outside the cluster core, in Abell 2125
(z=0.2465, richness class 4). With 20-cm VLA data, we detect continuum emission
from 90 cluster members. The multiwavelength properties of these galaxies
suggest that most of the radio emission is due to an enhanced star-formation
rate. The dynamical study of Miller et al (2004) suggests that Abell 2125 is
undergoing a major cluster-cluster merger, with our view within 30 degrees of
the merger axis and within 0.2 Gyr of core passage. The combination of
projection effects and the physical processes at work during this special time
in the cluster's evolution seem likely to be responsible for the unusual level
of activity we see in the cluster. We argue that tidal effects on individual
cluster members, often far from the cluster core, are responsible for the
increased star formation. Our results are consistent with the idea that disk
galaxies during this phase of a cluster's evolution undergo rapid evolution,
through a burst of star formation, on their way to becoming S0's.


title: Galactic Bulge Microlensing Events from the MACHO Collaboration

abstract:
  We present a catalog of 450 high signal-to-noise microlensing events observed
by the MACHO collaboration between 1993 and 1999. The events are distributed
throughout our fields and, as expected, they show clear concentration toward
the Galactic center. No optical depth is given for this sample since no
blending efficiency calculation has been performed, and we find evidence for
substantial blending. In a companion paper we give optical depths for the
sub-sample of events on clump giant source stars, where blending is not a
significant effect.
  Several events with sources that may belong to the Sagittarius dwarf galaxy
are identified. For these events even relatively low dispersion spectra could
suffice to classify these events as either consistent with Sagittarius
membership or as non-Sagittarius sources. Several unusual events, such as
microlensing of periodic variable source stars, binary lens events, and an
event showing extended source effects are identified. We also identify a number
of contaminating background events as cataclysmic variable stars.


title: The distribution and cosmic evolution of massive black hole spins

abstract:
  We study the expected distribution of massive black hole (MBH) spins and its
evolution with cosmic time in the context of hierarchical galaxy formation
theories. Our model uses Monte Carlo realizations of the merger hierarchy in a
LCDM cosmology, coupled to semi-analytical recipes, to follow the merger
history of dark matter halos, the dynamics of the MBHs they host, and their
growth via gas accretion and binary coalescences. The coalescence of comparable
mass holes increases the spin of MBHs, while the capture of smaller companions
in randomly-oriented orbits acts to spin holes down. We find that, given the
distribution of MBH binary mass ratios in hierarchical models, binary
coalescences alone do not lead to a systematic spin-up or spin-down of MBHs
with time: the spin distribution retains memory of its initial conditions. By
contrast, because of the Bardeen-Petterson effect, gas accretion via a thin
disk tends to spin holes up even if the direction of the spin axis changes
randomly in time. In our models, accretion dominates over black hole captures
and efficiently spins holes up. The spin distribution is heavily skewed towards
fast-rotating Kerr holes, is already in place at early epochs, and does not
change much below redshift 5. If accretion is via a thin disk, about 70% of all
MBHs are maximally rotating and have radiative efficiencies approaching 30%
(assuming a "standard'' spin-efficiency conversion). Even in the conservative
case where accretion is via a geometrically thick disk, about 80% of all MBHs
have spin parameters a/m > 0.8 and accretion efficiencies > 12%. Rapidly
spinning holes with high radiative efficiencies may satisfy constraints based
on comparing the local MBH mass density with the mass density inferred from
luminous quasars (Soltan's argument).


title: The Afterglow of Massive Black Hole Coalescence

abstract:
  The final merger of a pair of massive black holes in a galactic nucleus is
compelled by gravitational radiation. Gravitational waves from the mergers of
black holes of masses (10^5-10^7)(1+z)^{-1} Msun at redshifts of 1-20 will be
readily detectable by the Laser Interferometer Space Antenna (LISA), but an
electromagnetic afterglow would be helpful in pinpointing the source and its
redshift. Long before the merger, the binary "hollows out" any surrounding gas
and shrinks slowly compared to the viscous timescale of a circumbinary disk.
The inner gas disk is truncated at the radius where gravitational torque from
the binary balances the viscous torque, and accretion onto the black holes is
diminished. Initially, the inner truncation radius is able to follow the
shrinking binary inward. But eventually the gravitational radiation timescale
becomes shorter than the viscous timescale in the disk, leading to a merged
black hole surrounded by a hollow disk of gas. We show that the subsequent
viscous evolution of the hollow, radiation-pressure dominated disk will create
a ~10^{43.5}(M/10^6Msun) ergs s^{-1} X-ray source on a timescale
\~7(1+z)(M/10^6Msun)^{1.32} yr. This justifies follow-up monitoring of
gravitational wave events with next-generation X-ray observatories. Analysis of
the detailed light curve of these afterglows will yield new insights into the
subtle physics of accretion onto massive black holes.


title: Distribution of Spectral Lags in Gamma Ray Bursts

abstract:
  Using the data acquired in the Time To Spill (TTS) mode for long gamma-ray
bursts (GRBs) collected by the Burst and Transient Source Experiment on board
the Compton Gamma Ray Observatory (BATSE/CGRO), we have carefully measured
spectral lags in time between the low (25-55 keV) and high (110-320 keV) energy
bands of individual pulses contained in 64 multi-peak GRBs. We find that the
temporal lead by higher-energy gamma-ray photons (i.e., positive lags) is the
norm in this selected sample set of long GRBs. While relatively few in number,
some pulses of several long GRBs do show negative lags. This distribution of
spectral lags in long GRBs is in contrast to that in short GRBs. This apparent
difference poses challenges and constraints on the physical mechanism(s) of
producing long and short GRBs. The relation between the pulse peak count rates
and the spectral lags is also examined. Observationally, there seems to be no
clear evidence for systematic spectral lag-luminosity connection for pulses
within a given long GRB.


title:
Gamma-ray bursts and X-ray melting of material as a potential source of
  chondrules and planets

abstract:
  The intense radiation from a gamma-ray burst (GRB) is shown to be capable of
melting stony material at distances up to 300 light years which subsequently
cool to form chondrules. These conditions were created in the laboratory for
the first time when millimeter sized pellets were placed in a vacuum chamber in
the white synchrotron beam at the European Synchrotron Radiation Facility
(ESRF). The pellets were rapidly heated in the X-ray and gamma-ray furnace to
above 1400 C melted and cooled. This process heats from the inside unlike
normal furnaces. The melted spherical samples were examined with a range of
techniques and found to have microstructural properties similar to the
chondrules that come from meteorites. This experiment demonstrates that GRBs
can melt precursor material to form chondrules that may subsequently influence
the formation of planets. This work extends the field of laboratory
astrophysics to include high power synchrotron sources.


title: Doppler follow-up of OGLE transiting companions in the Galactic bulge

abstract:
  Two years ago, the OGLE-III survey (Optical Gravitational Lensing Experiment)
announced the detection of 54 short period multi-transiting objects in the
Galactic bulge (Udalski et al., 2002a, 2002b). Some of these objects were
considered to be potential hot Jupiters. In order to determine the true nature
of these objects and to characterize their actual mass, we conducted a radial
velocity follow-up of 18 of the smallest transiting candidates. We describe
here our procedure and report the characterization of 8 low mass star
transiting companions, 2 grazing eclipsing binaries, 2 triple systems, 1
confirmed exoplanet (OGLE-TR-56b), 1 possible exoplanet (OGLE-TR-10b), 1 clear
false positive and 3 unsolved cases. The variety of cases encountered in our
follow-up covers a large part of the possible scenarii occuring in the search
for planetary transits. As a by-product, our program yields precise masses and
radii of low mass stars.


title:
Simultaneous X-Ray and optical spectroscopy of the Seyfert galaxy Mrk
  993

abstract:
  We present the results of simultaneous XMM-Newton X-ray and 3.5m/CAHA optical
spectroscopic observations of the Seyfert galaxy Mrk 993. This galaxy exhibited
in the past significant variations of its broad emission lines which classified
it as Sy1, Sy1.5 and Sy1.9 in different epochs. In order to test the
X-ray/optical consistency of the unified AGN model we have compared the amount
of photoelectric X-ray absorption with the Balmer decrement of broad emission
line components. The optical data show that during our observations Mrk 993 was
in a Sy1.8 state with a Balmer decrement of 9. The X-ray absorbing gas amounts
only to 7E20 cmE-02, most likely due to the host galaxy. For a normal gas to
dust ratio in the absorbing material (expected to arise in the molecular torus)
both quantities are clearly discrepant with an intrinsic Balmer decrement of
3.4. We therefore conclude that the Balmer ratio is intrinsic rather than
produced by obscuration and therefore that in this object the optical broad
line emission properties are dictated by the physics of the broad line region
rather than orientation/obscuration effects.


title:
Time-resolved photometry of the nova remnants DM Gem, CP Lac, GI Mon,
  V400 Per, CT Ser and XX Tau

abstract:
  We present the first results of a photometric survey of poorly studied nova
remnants in the Northern Hemisphere. The main results are as follows: DM Gem
shows a modulation at 0.123 d (probably linked to the orbit) and rapid
variations at ~22 min. A moderate resolution spectrum taken at the time of the
photometric observations shows intense HeII 4686 and Bowen emission,
characteristic of an intermediate polar or a SW Sex star. Variability at 0.127
d and intense flickering (or quasi-periodic oscillations) are the main features
of the light curve of CP Lac. A 0.1-mag dip lasting for ~45 min is observed in
GI Mon, which could be an eclipse. A clear modulation (probably related to the
orbital motion) either at 0.179 d or 0.152 d is observed in the B-band light
curve of V400 Per. The results for CT Ser point to an orbital period close to
0.16 d. Intense flickering is also characteristic of this old nova. Finally, XX
Tau shows a possible periodic signal near 0.14 d and displays fast variability
at ~24 min. Its brightness seems to be modulated at ~5 d. We relate this long
periodicity to the motion of an eccentric/tilted accretion disc in the binary.


title: Stellar explosions: from supernovae to gamma-ray bursts

abstract:
  Current understanding of core collapse and thermonuclear supernovae is
reviewed. Recent progress in unveiling the nature of cosmic gamma-ray bursts
(GRB) is discussed, with the focus on the apparent link of several GRBs with an
energetic subclass of stellar explosions, type Ib/c core-collapse supernovae.
This relation provides the strong case that the GRB phenomenon is connected
with the final stages of massive star evolution and possibly with the formation
of neutron stars and black holes.


title:
Collimated high-energy photons and others possible observational effects
  of the photon angular and spectral distribution in gamma-ray bursts sources

abstract:
  Typical observational gamma-ray burst (GRB) spectra are discussed and, in
this connection, what is the origin of the compactness problem and how it was
solved at first. If the threshold for $e^{-}e^{+}$ pair production depends on
an angle between photon momenta, then another solution of the compactness
problem is possible. We discuss a possibility of the $\gamma$-rays collimation
and the dependence of photon beaming on photon energies. The list of basic
assumptions of the scenario describing the GRB source with energy $< 10^{49}$
ergs are adduced: the matter is about an alternative to the ultrarelativistic
fireball if {\it all} long-duration GRBs are related or physically connected
with {\it normal/unpeculiar} core-collapse supernovae (SNe). Namely, we
consider the questions about radiation pressure and how the jet arises on
account of even small asymmetry of the radiation field in a compact GRB source.
The possibility of a new approach to explanation of GRB phenomenon is shown.
Possible mechanisms of their generation in regions of size $< 10^8$cm are
discussed (a compact model of GRBs). Observational consequences of the compact
GRB energy release are considered.


title:
The stellar mass spectrum from non-isothermal gravoturbulent
  fragmentation

abstract:
  Identifying the processes that determine the initial mass function of stars
(IMF) is a fundamental problem in star formation theory. One of the major
uncertainties is the exact chemical state of the star forming gas and its
influence on the dynamical evolution. Most simulations of star forming clusters
use an isothermal equation of state (EOS). However, theoretical predictions and
observations suggest that the effective polytropic exponent gamma in the EOS
varies with density.
  We address these issues and study the effect of a piecewise polytropic EOS on
the formation of stellar clusters in turbulent, self-gravitating molecular
clouds using three-dimensional, smoothed particle hydrodynamics simulations. To
approximate the results of published predictions of the thermal behavior of
collapsing clouds, we increase the polytropic exponent gamma from 0.7 to 1.1 at
some chosen density n_c, which we vary. The change of thermodynamic state at
n_c selects a characteristic mass scale for fragmentation M_ch, which we relate
to the peak of the observed IMF. Our investigation generally supports the idea
that the distribution of stellar masses depends mainly on the thermodynamic
state of the star-forming gas. The thermodynamic state of interstellar gas is a
result of the balance between heating and cooling processes, which in turn are
determined by fundamental atomic and molecular physics and by chemical
abundances. Given the abundances, the derivation of a characteristic stellar
mass can thus be based on universal quantities and constants.


title: Cosmic-ray propagation properties for an origin in SNRs

abstract:
  We have studied the impact of cosmic-ray acceleration in SNR on the spectra
of cosmic-ray nuclei in the Galaxy using a series expansion of the propagation
equation, which allows us to use analytical solutions for part of the problem
and an efficient numerical treatment of the remaining equations and thus
accurately describes the cosmic-ray propagation on small scales around their
sources in three spatial dimensions and time. We found strong variations of the
cosmic-ray nuclei flux by typically 20% with occasional spikes of much higher
amplitude, but only minor changes in the spectral distribution. The locally
measured spectra of primary cosmic rays fit well into the obtained range of
possible spectra. We further showed that the spectra of the secondary element
Boron show almost no variations, so that the above findings also imply
significant fluctuations of the Boron-to-Carbon ratio. Therefore the commonly
used method of determining CR propagation parameters by fitting
secondary-to-primary ratios appears flawed on account of the variations that
these ratios would show throughout the Galaxy.


title: The 2003 radio outburst of a new X-ray transient: XTE J1720-318

abstract:
  We present radio observations of the black hole X-ray transient XTE
J1720-318, which was discovered in 2003 January as it entered an outburst. We
analyse the radio data in the context of the X-ray outburst and the broad-band
spectrum. An unresolved radio source was detected during the rising phase,
reaching a peak of nearly 5 mJy approximately coincident with the peak of the
X-ray lightcurve. Study of the spectral indices suggests that at least two
ejection events took place, the radio-emitting material expanding and becoming
optically thin as it faded. The broad-band spectra suggested that the accretion
disc dominated the emission, as expected for a source in the high/soft state.
The radio emission decayed to below the sensitivity of the telescopes for ~6
weeks but switched on again during the transition of the X-ray source to the
low/hard state. At least one ``glitch'' was superimposed on the otherwise
exponential decay of the X-ray lightcurve, which was reminiscent of the
multiple jet ejections of XTE J1859+226. We also present a K_s-band image of
XTE J1720-318 and its surrounding field taken with the VLT.


title:
INTEGRAL/SPI Limits on Electron-Positron Annihilation Radiation from the
  Galactic Plane

abstract:
  The center of our Galaxy is a known strong source of electron-positron
511-keV annihilation radiation. Thus far, however, there have been no reliable
detections of annihilation radiation outside of the central radian of our
Galaxy. One of the primary objectives of the INTEGRAL (INTErnational Gamma-RAy
Astrophysics Laboratory) mission, launched in Oct. 2002, is the detailed study
of this radiation. The Spectrometer on INTEGRAL (SPI) is a high resolution
coded-aperture gamma-ray telescope with an unprecedented combination of
sensitivity, angular resolution and energy resolution. We report results from
the first 10 months of observation. During this period a significant fraction
of the observing time was spent in or near the Galactic Plane. No positive
annihilation flux was detected outside of the central region (|l| > 40 deg) of
our Galaxy. In this paper we describe the observations and data analysis
methods and give limits on the 511-keV flux.


title: Spectro-Morphology of Galaxies

abstract:
  We present a quantitative method to classify galaxies, based on
multi-wavelength data and elaborated from the properties of nearby galaxies.
Our objective is to define an evolutionary method that can be used for low and
high redshift objects. We estimate the concentration of light (C) at the galaxy
center and the 180 degree-rotational asymmetry (A), computed at several
wavelengths, from ultraviolet (UV) to I-band. The variation of the indices of
concentration and asymmetry with the wavelength reflects the proportion and the
distribution of young and old stellar populations in galaxies. In general C is
found to decrease from optical to UV, and A is found to increase from optical
to UV: the patchy appearance of galaxies in UV with no bulge is often very
different from their counterpart at optical wavelengths, with prominent bulges
and more regular disks. The variation of C and A with the wavelength is
quantified. By this way, we are able to distinguish five types of galaxies that
we call spectro-morphological types: compact, ringed, spiral, irregular and
central-starburst galaxies, which can be differentiated by the repartition of
their stellar populations. We discuss in detail the morphology of galaxies of
the sample, and describe the morphological characteristics of each
spectro-morphological type. We apply spectro-morphology to three objects at a
redshift z=1 in the Hubble Deep Field North, that gives encouraging results for
applications to large samples of high-redshift galaxies. This method of
morphological classification could be used to study the evolution of the
morphology with the redshift and is expected to bring observational constraints
on scenarios of galaxy evolution.


title: Gravitational wave radiation from the coalescence of white dwarfs

abstract:
  We compute the emission of gravitational radiation from the merging of a
close white dwarf binary system. This is done for a wide range of masses and
compositions of the white dwarfs, ranging from mergers involving two He white
dwarfs, mergers in which two CO white dwarfs coalesce to mergers in which a
massive ONe white dwarf is involved. In doing so we follow the evolution of
binary system using a Smoothed Particle Hydrodynamics code. Even though the
coalescence process of the white dwarfs involves considerable masses, moving at
relatively high velocities with a high degree of asymmetry we find that the
signature of the merger is not very strong. In fact, the most prominent feature
of the coalescence is that in a relatively small time scale (of the order of
the period of the last stable orbit, typically a few minutes) the sources stop
emitting gravitational waves. We also discuss the possible implications of our
calculations for the detection of the coalescence within the framework of
future space-borne interferometers like LISA.


title:
The peculiar galaxy Mkn 298 revisited through integral field
  spectroscopy

abstract:
  Spectroscopic and imaging data of the peculiar galaxy Mkn 298 are presented
in this paper. Narrow-band Halpha and broad-band R images are used to study the
star formation rate in the galaxy and its morphology, which is typical of a
merging system. Long-slit and integral field spectra are used to assess the
kinematics of gas and stars, and the nature of the ionizing source at different
distances from the nucleus. In particular, the nucleus of Mkn 298 is
characterized by peculiar line ratios: [NII] 6583/Halpha is typical of HII-like
regions, while [OI] 6300/Halpha could indicate the presence of an active
galactic nucleus. We show that models where a shock component is added to
photoionization from a starburst allow to reproduce the observed line ratios.
Mkn 298 is thus most likely a star forming galaxy, rather than a galaxy hosting
an active nucleus.


title:
Non-Ideal Equation of State, Refraction and Opacities in Very Cool,
  Helium-Rich White Dwarf Atmospheres

abstract:
  The atmospheres of cool, helium-rich white dwarfs constitute an exotic and
poorly explored physical regime of stellar atmospheres. Under physical
conditions where the temperature varies from $\rm 1000K$ to $\rm 10000K$, the
density can reach values as large as $\rm 2 g/cm^{3}$, and the pressure is as
high as $\rm 1 Mbar$, the atmosphere is no longer an ideal gas and must be
treated as a dense fluid. Helium atoms become strongly correlated and
refraction effects are present. Opacity sources such as $\rm He^{-}$ free-free
absorption must be calculated with a formalism that has never been applied to
astrophysical opacities. These effects have been ignored in previous models of
cool white dwarf atmospheres.


title: Gamma Rays from Kaluza-Klein Dark Matter

abstract:
  A TeV gamma-ray signal from the direction of the Galactic center (GC) has
been detected by the H.E.S.S. experiment. Here, we investigate whether
Kaluza-Klein (KK) dark matter annihilations near the GC can be the explanation.
Including the contributions from internal bremsstrahlung as well as subsequent
decays of quarks and tau leptons, we find a very flat gamma-ray spectrum which
drops abruptly at the dark matter particle mass. For a KK mass of about 1 TeV,
this gives a good fit to the H.E.S.S. data below 1 TeV. A similar model, with
gauge coupling roughly three times as large and a particle mass of about 10
TeV, would give both the correct relic density and a photon spectrum that fits
the complete range of data.


title:
Correlating the CMB with Luminous Red Galaxies : The Integrated
  Sachs-Wolfe Effect

abstract:
  We present a 2.5 sigma detection of the Integrated Sachs-Wolfe (ISW) effect
and discuss the constraints it places on cosmological parameters. We
cross-correlate microwave temperature maps from the WMAP satellite with a 4000
deg^2 luminous red galaxy (LRG) overdensity map measured by the Sloan Digital
Sky Survey. Accurate photometric redshifts allow us to perform a reliable
auto-correlation analysis of the LRGs, eliminating the uncertainty in the
galaxy bias, and combined with cross correlation signal, constrains
cosmological parameters -- in particular, the matter density. We find a 2.5
sigma signal in the Ka, Q, V, and W WMAP bands, after combining the information
from multipoles 2 <= l < 400. This is consistent with the expected amplitude of
the ISW effect, but requires a lower matter density than is usually assumed:
the amplitude, parametrized by the galaxy bias assuming \Omega_M=0.3,
\Omega_\Lambda=0.7 and \sigma_8=0.9, is b_g = 4.05 \pm 1.54 for V band, with
similar results for the other bands. This should be compared to b_g = 1.82 \pm
0.02 from the auto-correlation analysis. These data provide only a weak
confirmation (2.5 sigma) of dark energy, but provide a significant upper limit:
\Omega_\Lambda=0.80_{-0.06}^{+0.03} (1 sigma)_{-0.19}^{+0.05} (2 sigma),
assuming a cosmology with \Omega_M+\Omega_\Lambda=1, \Omega_b = 0.05, and
\sigma_8=0.9, and w=-1. The weak cross-correlation signal rules out low matter
density/high dark energy density universes and, in combination with other data,
strongly constrains models with w<-1.3. We provide a simple prescription to
incorporate these constraints into cosmological parameter estimation methods
for (\Omega_M, \sigma_8,w). (abridged)


title: 21 years of Timing PSR B1509-58

abstract:
  We present an updated timing solution for the young, energetic pulsar PSR
B1509-58 based on 21.3 years of radio timing data and 7.6 years of X-ray timing
data. No glitches have occurred in this time span, in contrast to other
well-studied young pulsars, which show frequent glitches. We report a
measurement of the third frequency derivative of (-1.28+/-0.21)x10^(-31)
s^(-4). This value is 1.65 standard deviations from, i.e. consistent with, that
predicted by the simple constant magnetic dipole model of pulsar spin-down. We
measured the braking index to be n=2.839+/-0.003 and show that it varies by
1.5% over 21.3 yr due to contamination from timing noise. Results of a
low-resolution power spectral analysis of the significant noise apparent in the
data yield a spectral index of alpha=-4.6+/-1.0 for the red noise component.


title: FUSE Measurements of Interstellar Fluorine

abstract:
  The source of fluorine is not well understood, although core-collapse
supernovae, Wolf-Rayet stars, and asymptotic giant branch stars have been
suggested. A search for evidence of the nu process during Type II supernovae is
presented. Absorption from interstellar F I is seen in spectra of HD 208440 and
HD 209339A acquired with the Far Ultraviolet Spectroscopic Explorer. In order
to extract the column density for F I from the line at 954 A, absorption from
H2 has to be modeled and then removed. Our analysis indicates that for H2
column densities less than about 3 x 10^20 cm^-2, the amount of F I can be
determined from lambda 954. For these two sight lines, there is no clear
indication for enhanced F abundances resulting from the nu process in a region
shaped by past supernovae.


title:
Extraplanar Dust: a Tracer of Cold Dense Gas in the Thick Disks of
  Spiral Galaxies

abstract:
  The interstellar thick disks of galaxies contain not only gas, but
significant quantities of dust. Most of our knowledge of extraplanar dust in
disk galaxies comes from direct broadband optical imaging of these systems,
wherein the dust is identified due to the irregular extinction it produces
against the thick disk and bulge stars. This observational technique is
sensitive to only the most dense material, and we argue much of the material
identified in this way traces a cold phase of the interstellar thick disks in
galaxies. The presence of a cold, dense phase likely implies the interstellar
pressures in the thick disks of spiral galaxies can be quite high. This dense
phase of the interstellar medium may also fueling thick disk star formation,
and H-alpha observations are now revealing H II regions around newly-formed OB
stars associations in several galaxies. We argue that the large quantities of
dust and the morphologies of the structures traced by the dust imply that much
of the extraplanar material in disk galaxies must have been expelled from the
underlying thin disk.


title: Massive Black Hole Binary Evolution

abstract:
  Coalescence of binary supermassive black holes (SBHs) would constitute the
strongest sources of gravitational waves to be observed by LISA. While the
formation of binary SBHs during galaxy mergers is almost inevitable,
coalescence requires that the separation between binary components first drop
by a few orders of magnitude, due presumably to interaction of the binary with
stars and gas in a galactic nucleus. This article reviews the observational
evidence for binary SBHs and discusses how they would evolve. No completely
convincing case of a bound, binary SBH has yet been found, although a handful
of systems (e.g. interacting galaxies; remnants of galaxy mergers) are now
believed to contain two SBHs at projected separations of roughly one kpc.
N-body studies of binary evolution in gas-free galaxies have reached large
enough particle numbers to reproduce the slow, "diffusive" refilling of the
binary's loss cone that is believed to characterize binary evolution in real
galactic nuclei. While some of the results of these simulations -- e.g. the
binary hardening rate and eccentricity evolution -- are strongly $N$-dependent,
others -- e.g. the "damage" inflicted by the binary on the nucleus -- are not.
Luminous early-type galaxies often exhibit depleted cores with masses of 1-2
times the mass of their nuclear SBHs, consistent with the predictions of the
binary model. Studies of the interaction of massive binaries with gas are still
in their infancy, although much progress is expected in the near future. Binary
coalescence has a large influence on the spins of SBHs, even for mass ratios as
extreme as 10:1, and evidence of spin-flips may have been observed.


title: Principles of the Theory of Vortex Gravitation

abstract:
  The developed theory proves that a universal vortex motion, along with the
pressure variation in a space continuum called ether, is actually the source of
the universal gravitation and creation of celestial bodies and their motion in
the Universe. Calculations of the gravitation forces are carried out on the
basis of the laws of mechanics of continua and (or) aerodynamics with the use
of the Navier-Stokes equations. As a result of the solution, an algebraic
formula for the gravitation forces is obtained. The reliability of this formula
is supported by its conformity to the astronomical data, and also to the Newton
empirical formula for universal gravitation. The main advantage of the proposed
theory is that, on the basis of it, it is possible to explain all the phenomena
and laws observed in the cosmic space, viz.: motion of celestial bodies; mutual
closing and moving away of galaxies; an origin of celestial bodies, black
holes, and the Universe as a whole; the nature of gravity; the speed of
gravitation; the strengths of magnetic fields of celestial bodies, etc.


title:
Spectral disentangling of the triple system DG Leo: orbits and chemical
  composition

abstract:
  DG Leo is a spectroscopic triple system composed by 3 stars of late-A
spectral type, one of which was suggested to be a delta Scuti star. Seven
nights of observations at high spectral and high time resolution at the
Observatoire de Haute-Provence with the ELODIE spectrograph were used to obtain
the component spectra by applying a Fourier transform spectral disentangling
technique. Comparing these with synthetic spectra, the stellar fundamental
parameters (effective temperature, surface gravity, projected rotation velocity
and chemical composition) are derived. The inner binary consists of two Am
components, at least one of which is not yet rotating synchronously at the
orbital period though the orbit is a circular one. The distant third component
is confirmed to be a delta Scuti star with normal chemical composition.


title: Time series analysis in Astronomy: limits and potentialities

abstract:
  In this paper we consider the problem of the limits concerning the physical
information that can be extracted from the analysis of one or more time series
(light curves) typical of astrophysical objects. On the basis of theoretical
considerations and numerical simulations, we show that with no a priori
physical model there are not so many possibilities to obtain interpretable
results. For this reason, the practice to develop more and more sophisticated
statistical methods of time series analysis is not very productive. Only
techniques of data analysis developed in a specific physical context can be
expected to provide useful results. The field of {\it stochastic dynamics}
appears to be an useful framework for such an approach. In particular, it is
shown that modelling the experimental time series by means of the stochastic
differential equations (SDE) represents a valuable tool of analysis. For
example, the use of SDE permits to make the analysis of a continuous signal
independent from the frequency sampling with which the experimental time series
have been obtained. In this respect, an efficient approach based on the
extended Kalman-filter technique is presented. Freely downloadable software is
made available.


title: Torus models for obscuration in type 2 AGN

abstract:
  We discuss a clumpy model of obscuring dusty tori around AGN. Cloud-cloud
collisions lead to an effective viscosity and a geometrically thick accretion
disk, which has the required properties of a torus.
  Accretion in the combined gravitational potential of central black hole and
stellar cluster generates free energy, which is dissipated in collisions, and
maintains the thickness of the torus. A quantitative treatment for the torus in
the prototypical Seyfert 2 nucleus of NGC 1068 together with a radiative
transfer calculation for NIR re-emission from the torus is presented.


title: A new reddening for RR Tel from the HeII Paschen lines

abstract:
  From the available STIS data of RR Tel, that have provided a coverage with
absolutely calibrated data in a wide wavelength range, we have obtained a new
determination of its reddening (E(B-V)=0.00) from the comparison of the
observed HeII Paschen lines decrement relative to HeII lambda 4686 (for 24 HeII
Paschen lines down to the region of the head of the series near lambda 2060 A)
with the theoretical one as given in Storey and Hummer (1995) for case B,
T=10,000 K and log Ne=6. This new E(B-V)=0.0 value has been confirmed from a
re-analysis of the IUE low resolution data. We recall that the so far generally
adopted value in the literature has been E(B-V)=0.10 as obtained by Penston et
al. (1983).


title:
Modeling CHANDRA Low Energy Transmission Grating Spectrometer
  Observations of Classical Novae with PHOENIX. I. V4743 Sagittarii

abstract:
  We use the PHOENIX code package to model the X-ray spectrum of Nova V4743
Sagittarii observed with the LETGS onboard the Chandra satellite on March 2003.
Our atmosphere models are 1D spherical, expanding, line blanketed, and in full
NLTE. To analyze nova atmospheres and related systems with an underlying
nuclear burning envelope at X-ray wavelengths, it was necessary to update the
code with new microphysics, as discussed in this paper. We demonstrate that the
X-ray emission is dominated by thermal bremsstrahlung and that the hard X-rays
are dominated by Fe and N absorption. The best fit to the observation is
provided at a temperature of T_eff = 5.8 x 10^5 K, with L_bol = 50 000 L_sun.
The models are calculated for solar abundances. It is shown that the models can
be used to determine abundances in the nova ejecta.


title: Stellar Mass Spectra from Non-Isothermal Gravoturbulent Fragmentation

abstract:
  (abridged version) Identifying the processes that determine the initial mass
function of stars (IMF) is a fundamental problem in star formation theory. One
of the major uncertainties is the exact chemical state of the star forming gas
and its influence on the dynamical evolution. Most simulations of star forming
clusters use an isothermal equation of state (EOS). We address these issues and
study the effect of a piecewise polytropic EOS on the formation of stellar
clusters in turbulent, self-gravitating molecular clouds. We increase the
polytropic exponent gamma from 0.7 to 1.1 at some chosen density n_c, which we
vary from from 4.3x10^4 cm^-3 to 4.3x10^7 cm^-3. The change of thermodynamic
state at n_c selects a characteristic mass scale for fragmentation M_ch, which
we relate to the peak of the observed IMF. We find a relation M_ch ~ n_c^-0.5,
supporting the idea that the distribution of stellar masses largely depends on
the thermodynamic state of the star-forming gas.