title:
Multipole Vectors--a new representation of the CMB sky and evidence for
  statistical anisotropy or non-Gaussianity at 2<=l<=8

abstract:
  We propose a novel representation of cosmic microwave anisotropy maps, where
each multipole order l is represented by l unit vectors pointing in directions
on the sky and an overall magnitude. These "multipole vectors and scalars"
transform as vectors under rotations. Like the usual spherical harmonics,
multipole vectors form an irreducible representation of the proper rotation
group SO(3). However, they are related to the familiar spherical harmonic
coefficients, alm, in a nonlinear way, and are therefore sensitive to different
aspects of the CMB anisotropy. Nevertheless, it is straightforward to determine
the multipole vectors for a given CMB map and we present an algorithm to
compute them. Using the WMAP full-sky maps, we perform several tests of the
hypothesis that the CMB anisotropy is statistically isotropic and Gaussian
random. We find that the result from comparing the oriented area of planes
defined by these vectors between multipole pairs 2<=l1!=l2<=8 is inconsistent
with the isotropic Gaussian hypothesis at the 99.4% level for the ILC map and
at 98.9% level for the cleaned map of Tegmark et al. A particular correlation
is suggested between the l=3 and l=8 multipoles, as well as several other
pairs. This effect is entirely different from the now familiar planarity and
alignment of the quadrupole and octupole: while the aforementioned is fairly
unlikely, the multipole vectors indicate correlations not expected in Gaussian
random skies that make them unusually likely. The result persists after
accounting for pixel noise and after assuming a residual 10% dust contamination
in the cleaned WMAP map. While the definitive analysis of these results will
require more work, we hope that multipole vectors will become a valuable tool
for various cosmological tests, in particular those of cosmic isotropy.


title: Liberating the Inflaton from Primordial Spectrum Constraints

abstract:
  I discuss a mechanism that renders the spectral index of the primordial
spectrum and the inflationary stage independent of each other. If a scalar
field acquires an appropriate time-dependent mass, it is possible to generate
an adiabatic, Gaussian scale invariant spectrum of density perturbations during
any stage of inflation. As an illustration, I present a simple model where the
time-dependent mass arises from the coupling of the inflaton to a second
scalar. The mechanism I propose might help to implement a successful
inflationary scenario in particle physics theories that do not yield slow-roll
potentials.


title:
Cosmological Simulations of Elliptical Galaxy Formation in LCDM and LWDM
  Cosmologies

abstract:
  We present the results of a series of gas dynamical cosmological simulations
of the formation of individual massive field galaxies in the standard
concordance \LCDM and in a \LWDM cosmology. The galaxies form in an initial
burst of star formation followed by accretion of small satellites. The
simulated galaxies are old ($\approx$ 10 $Gyrs$) hot stellar systems with
masses of $\approx 1.7 \times 10^{11} M_{\odot}$. Baryonic matter dominates the
mass in the luminous part of the galaxies up to $\approx 5$ effective radii.
The \LCDM galaxy is a slowly rotating spheroidal stellar system (E2) with
predominantly disky isophotes. The line-of-sight velocity distributions deviate
from Gaussian shape and $h_3$ is anticorrelated with $v_{los}$. The
corresponding \LWDM galaxy is more elongated (E3 - E4) and rotates faster. The
anisotropy parameter $(v/\sigma)^*$ is close to unity. Within the uncertainties
of $M/L$ both galaxies follow the Fundamental Plane. We conclude that the
properties of the two galaxies simulated in the \LCDM and \LWDM cosmology are
in good agreement with observations of intermediate mass elliptical or S0
galaxies (abstract abbreviated).


title: Searching for Star Formation Beyond Reionization

abstract:
  The goal of searching back in cosmic time to find star formation during the
epoch of reionization will soon be within reach. We assess the detectability of
high-redshift galaxies by combining cosmological hydrodynamic simulations of
galaxy formation, stellar evolution models appropriate for the first
generations of stars, and estimates of the efficiency for Lyman alpha to escape
from forming galaxies into the intergalactic medium. Our simulated observations
show that Lyman alpha emission at z ~ 8 may be observable in the near-infrared
with 8-meter class telescopes and present-day technology. Not only is the
detection of early star-forming objects vital to understanding the underlying
cause of the reionization of the universe, but the timely discovery of a z > 7
star-forming population -- or even an interesting upper limit on the emergent
flux from these objects -- will have implications for the design of the next
generation of ground- and space-based facilities.


title: Statistical Uncertainty in the Re-Analysis of Polarization in GRB021206

abstract:
  We recently reported the first detection of an astrophysical gamma-ray
polarization from GRB021206 using the Reuven Ramaty High Energy Solar
Spectroscopic Imager (RHESSI) spacecraft. Our analysis suggested gamma-ray
polarization at an astoundingly high level, 80+/-20%. A recent manuscript
re-analyzes this event in the RHESSI data, and sets an upper limit on potential
polarization of 4.1% -- clearly inconsistent with our initial analysis. This
manuscript raises a number of important concerns about the analysis, which are
already being addressed in a separate methods paper under preparation. We note
here, however, that the limit set on the potential polarization by this
re-analysis is significantly underestimated using their novel statistical
methods.


title:
Deep near-infrared imaging of RDCS J1252.9-2927 at z=1.237: The
  colour-magnitude diagram

abstract:
  We present deep SofI and ISAAC near-infrared imaging data of the X-ray
luminous galaxy cluster RDCS J1252.9-2927. The ISAAC data were taken at the ESO
Very Large Telescope under very good seeing conditions and reach limiting Vega
magnitudes of 25.6 and 24.1 in the J- and Ks-bands respectively. The image
quality is 0.45 arc seconds in both passbands. We use these data to construct a
colour-magnitude (C-M) diagram of galaxies that are within 20 arc seconds of
the cluster center and brighter than Ks=24, which is five magnitudes fainter
than the apparent magnitude of a L* galaxy in this cluster. The C-M relation is
clearly identified as an over-density of galaxies with colours near J-Ks=1.85.
The slope of the relation is -0.05 and the intrinsic scatter is 0.06
magnitudes. Both the slope and the scatter are consistent with the values
measured for clusters at lower redshifts. These quantities have not evolved
from z=0 to z=1.24. However, significant evolution in the mean J-Ks colour is
detected. On average, the galaxies in RDCS J1252.9-2927 are 0.25 magnitudes
bluer than early-type galaxies in the Coma cluster. Using instantaneous
single-burst solar-metallicity models, the average age of galaxies in the
center of RDCS J1252.9-2927 is 2.7 Gyrs.


title:
Morphology of Rising Hydrodynamic and Magneto-hydrodynamic Bubbles from
  Numerical Simulations

abstract:
  Recent Chandra and XMM-Newton observations of galaxy cluster cooling flows
have revealed X-ray emission voids of up to 30 kpc in size that have been
identified with buoyant, magnetized bubbles. Motivated by these observations,
we have investigated the behavior of rising bubbles in stratified atmospheres
using the FLASH adaptive-mesh simulation code. We present results from 2-D
simulations with and without the effects of magnetic fields, and with varying
bubble sizes and background stratifications. We find purely hydrodynamic
bubbles to be unstable; a dynamically important magnetic field is required to
maintain a bubble's integrity. This suggests that, even absent thermal
conduction, for bubbles to be persistent enough to be regularly observed, they
must be supported in large part by magnetic fields. Thermal conduction
unmitigated by magnetic fields can dissipate the bubbles even faster. We also
observe that the bubbles leave a tail as they rise; the structure of these
tails can indicate the history of the dynamics of the rising bubble.


title: X- and Gamma-ray Studies of Cas A: Exposing Core Collapse to the Core

abstract:
  In this review of X-ray and gamma-ray observations of Cas A, evidence is
discussed that Cas A was a Type Ib supernova of a Wolf-Rayet star with a main
sequence mass between 22-25 Msun, that exploded after stellar wind loss had
reduced its mass to ~6 Msun. The observed kinematics and the high Ti-44 yield
indicate that the supernova explosion was probably assymetric, with a kinetic
energy of ~2x10^51 erg.


title: V1494 Aql: Eclipsing Fast Nova with an Unusual Orbital Light Curve

abstract:
  We present time-resolved photometry of V1494 Aql (Nova Aql 1999 No. 2:
http://www.kusastro.kyoto-u.ac.jp/vsnet/Novae/v1494aql.html) between 2001
November and 2003 June. The object is confirmed to be an eclipsing nova with a
period of 0.1346138(2) d. The eclipses were present in all observed epochs. The
orbital light curve shows a rather unusual profile, consisting of a bump-like
feature at phase 0.6-0.7 and a dip-like feature at phase 0.2-0.4. These
features were probably persistently present in all available observations
between 2001 and 2003. A period analysis outside the eclipses has confirmed
that these variations have a period common to the orbital period, and are
unlikely interpreted as superhumps. We suspect that structure (probably in the
accretion disk) fixed in the binary rotational frame is somehow responsible for
this feature.


title:
Identification of Nearby Active Galaxies as Sources of Cosmic Rays Above
  4x10^19 ev

abstract:
  Arrival directions of 63 extensive air showers with energies 4 10^19<E<=3
10^20 eV detected by the AGASA, Yakutsk, and Haverah Park arrays are analysed
in order to identify possible sources of cosmic rays with these energies. We
searched for active galactic nuclei within error boxes around the
shower-arrival directions and calculated the probabilities of objects being in
the error boxes by chance. Our previous result obtained in 1996-2001 (see
references in the text) is confirmed: the probabilities are small, P>3 sigma
(sigma is the parameter of Gaussian distribution)for Seyfert galaxies with
redshifts z<0.01. The Seyfert galaxies are characterized by moderate
luminosities (L<10^46 erg/s) and weak radio and X-ray emission.
  Astronomical and Astrophysical Transactions, 2003, v.22, #6, pp.(TBD)


title: A Deep, High-Resolution Survey at 74 MHz

abstract:
  We present a 74 MHz survey of a 165 square degree region located near the
north galactic pole. This survey has an unprecedented combination of both
resolution (25'' FWHM) and sensitivity (RMS noise as low as 24 mJy/beam). We
detect 949 sources at the 5-sigma level in this region, enough to begin
exploring the nature of the 74 MHz source population. We present differential
source counts, spectral index measurements and the size distribution as
determined from counterparts in the high resolution FIRST 1.4 GHz survey. We
find a trend of steeper spectral indices for the brighter sources. Further,
there is a clear correlation between spectral index and median source size,
with the flat spectrum sources being much smaller on average. Ultra-steep
spectrum objects (alpha < -1.2) are identified, and we present high resolution
VLA follow-up observations of these sources which, identified at such a low
frequency, are excellent candidates for high redshift radio galaxies.


title: How far can the generalized second law be generalized?

abstract:
  Jacob Bekenstein's identification of black hole event horizon area with
entropy proved to be a landmark in theoretical physics. In this paper we trace
the subsequent development of the resulting generalized second law of
thermodynamics (GSL), especially its extension to incorporate cosmological
event horizons. In spite of the fact that cosmological horizons do not
generally have well-defined thermal properties, we find that the GSL is
satisfied for a wide range of models. We explore in particular the case of an
asymptotically de Sitter universe filled with a gas of small black holes as a
means of casting light on the relative entropic 'worth' of black hole versus
cosmological horizon area. We present some numerical solutions of the
generalized total entropy as a function of time for certain cosmological
models, in all cases confirming the validity of the GSL.


title:
An Astronomical Evidence of Existence of Quark Matter and the Prediction
  for Submillisecond Pulsars

abstract:
  We derive the bulk viscous time scale of neutron stars with quark matter
core, i.e. hybrid stars. The r-mode instability windows of the stars show the
theoretical result accords with the rapid rotation pulsar data. The fit gives a
strong indication for the existence of quark matter in the interior of neutron
stars. Hybrid stars instead of neutron or strange stars may result in
submillisecond pulsars if they exist.


title:
Change of Primary Cosmic Radiation Nuclear Conposition in the Energy
  Range $10^{15} - 10^{17}$ eV as a Result of the Interaction with the
  Interstellar Cold Background of Light Particles

abstract:
  In this paper the updated arguments in favor of a simple model, explaining
from the united positions all peculiarities of the Extensive Air Shower (EAS)
hadron E_h(E_0) (and muon E_mu(E_0)) component energy fluxes dependence on the
primary particle energy E_0 in the primary energy region 10^{15} - 10^{17} eV
are represented. These peculiarities have shapes of consequent distinct deeps
of a widths dE_h/E_h of the order of 0.2 and of relative amplitudes dL/L of the
order of {0.1 - 1.0}, and are difficult to be explained via known astrophysical
mechanisms of particle generation and acceleration. In the basis of the model
lies the destruction of the Primary Cosmic Radiation (PCR) nuclei on some
monochromatic background of interstellar space, consisting of the light
particles of the mass in the area of 36 eV (maybe the component of a dark
matter). The destruction thresholds of PCR different nuclear components
correspond to the peculiarities of E_h(E_0). In this work the results of the
recent treatment of large statistical material are analyzed. The experimental
results are in good agreement with the Monte-Carlo calculations carried out in
the frames of the proposed model.


title: Structuring and support by Alfven waves around prestellar cores

abstract:
  Observations of molecular clouds show the existence of starless, dense cores,
threaded by magnetic fields. Observed line widths indicate these dense
condensates to be embedded in a supersonically turbulent environment. Under
these conditions, the generation of magnetic waves is inevitable. In this
paper, we study the structure and support of a 1D plane-parallel,
self-gravitating slab, as a monochromatic, circularly polarized Alfven wave is
injected in its central plane. Dimensional analysis shows that the solution
must depend on three dimensionless parameters. To study the nonlinear,
turbulent evolution of such a slab, we use 1D high resolution numerical
simulations. For a parameter range inspired by molecular cloud observations, we
find the following. 1) A single source of energy injection is sufficient to
force persistent supersonic turbulence over several hydrostatic scale heights.
2) The time averaged spatial extension of the slab is comparable to the
extension of the stationary, analytical WKB solution. Deviations, as well as
the density substructure of the slab, depend on the wave-length of the injected
wave. 3) Energy losses are dominated by loss of Poynting-flux and increase with
increasing plasma beta. 4) Good spatial resolution is mandatory, making similar
simulations in 3D currently prohibitively expensive.


title: MHD Disk Winds in PNe and pPNe

abstract:
  Winds from accretion disks have been proposed as the driving source for
precessing jets and extreme bipolar morphologies in Planetary Nebulae (PNe) and
proto-PNe (pPNe). Here we apply MHD disk wind models to PNe and pPNe by
estimating separately the asymptotic MHD wind velocities and mass loss rates.
We show that the resulting winds can recover the observed momentum and energy
input rates for PNe and pPNe.


title: Quantitative Morphology of Galaxies in the Core of the Coma Cluster

abstract:
  We present a quantitative morphological analysis of 187 galaxies in a region
covering the central 0.28 square degrees of the Coma cluster. Structural
parameters from the best-fitting Sersic r^{1/n} bulge plus, where appropriate,
exponential disc model, are tabulated here. This sample is complete down to a
magnitude of R=17 mag. By examining the Edwards et al. (2002) compilation of
galaxy redshifts in the direction of Coma, we find that 163 of the 187 galaxies
are Coma cluster members, and the rest are foreground and background objects.
For the Coma cluster members, we have studied differences in the structural and
kinematic properties between early- and late-type galaxies, and between the
dwarf and giant galaxies. Analysis of the elliptical galaxies reveals
correlations among the structural parameters similar to those previously found
in the Virgo and Fornax clusters. Comparing the structural properties of the
Coma cluster disc galaxies with disc galaxies in the field, we find evidence
for an environmental dependence: the scale lengths of the disc galaxies in Coma
are 30% smaller. A kinematical analysis shows marginal differences between the
velocity distributions of ellipticals with Sersic index n<2 (dwarfs) and those
with n>2 (giants); the dwarf galaxies having a greater (cluster) velocity
dispersion. Finally, our analysis of all 421 background galaxies reveals a
non-uniform distribution in redshift with contrasts in density ~3,
characterized by a void extending from ~10,000 to ~20,000 km s^{-1}, and two
dense and extended structures centred at ~20,000 and ~47,000 km s^{-1}.


title: Inner Halo Shapes of Dwarf Galaxies: Resolving the Cusp/Core Problem

abstract:
  We derive inner dark matter halo density profile slopes for a sample of 200
dwarf galaxies by inverting rotation curves obtained from high-quality,
long-slit optical spectra. Using simulations to assess the impact of long-slit
observing and data processing errors on our measurements, we conclude that our
observations are consistent with the cuspy halos predicted by the CDM paradigm.


title: Observations of Type Ia Supernovae, and Challenges for Cosmology

abstract:
  Observations of Type Ia supernovae (SNe Ia) reveal correlations between their
luminosities and light-curve shapes, and between their spectral sequence and
photometric sequence. Assuming SNe Ia do not evolve at different redshifts, the
Hubble diagram of SNe Ia may indicate an accelerating Universe, the signature
of a cosmological constant or other forms of dark energy. Several studies raise
concerns about the evolution of SNe Ia (e.g., the peculiarity rate, the
risetime, and the color of SNe Ia at different redshifts), but all these
studies suffer from the difficulties of obtaining high-quality spectroscopy and
photometry for SNe Ia at high redshifts. There are also some troubling cases of
SNe Ia that provide counterexamples to the observed correlations, suggesting
that a secondary parameter is necessary to describe the whole SN Ia family.
Understanding SNe Ia both observationally and theoretically will be the key to
boosting confidence in the SN Ia cosmological results.


title:
Determining the properties of galaxy 2237+0305 using gravitational
  lensing

abstract:
  We have studied the mass distribution in the lensing galaxy 2237+0305 using
constraints from both gravitational lensing and photometric and spectroscopic
observations. We find that with sufficient dynamical information we can
constrain the mass-to-light ratio of the luminous components and determine the
dynamical contribution of the disk. In addition, future observations should
allow us to place constraints on the shape of the dark matter halo and its
inner slope.


title: A Closer Look at the Mond No-Go Statement for Purely Metric Formulations

abstract:
  We reexamine the assumptions made in arriving at a no-go statement for purely
metric formulations of MOND. Removing the requirement of gravitational
stability at appropriate scales gives life to the possibility of a purely
metric theory of MOND.


title: Discrete Spectrum of Inflationary Fluctuations

abstract:
  It is conjectured that inflation, taking account of quantum gravity, leads to
a discrete spectrum of cosmological perturbations, instead of the continuous
Gaussian spectrum predicted by standard field theory in an unquantized
background. Heuristic models of discrete spectra are discussed, based on an
inflaton mode with self gravity, a lattice of amplitude states, an entangled
ensemble of modes, and the holographic or covariant entropy bound. Estimates
are given for the discreteness observable in cosmic background anisotropy,
galaxy clustering, and gravitational wave backgrounds.


title: AGN Physics from QSO Clustering

abstract:
  We review the current status of QSO clustering measurements, particular with
respect to their relevance in understanding AGN physics. Measurements based on
the 2dF QSO Redshift Survey (2QZ) find a scale length for QSO clustering of
s_0=5.76(+0.17-0.27) h-1 Mpc at a redshift <z>~1.5, very similar to low
redshift galaxies. There is no evidence of evolution in the clustering of QSOs
from z~0.5 to z~2.2. This lack of evolution and low clustering amplitude
suggests a short life time for AGN activity of the order ~10^6-10^7 years.
Large surveys such at the 2QZ and SDSS also allow the the study of QSO
environments in 3D for the first time (at least at low redshift), early results
from this work seem to show no difference between the environments of QSOs and
normal galaxies. Future studies e.g. measuring clustering as a function of
black hole mass, and deep QSO surveys should provide further insight into the
formation and evolution of AGN.


title: What X-rays tell us about dark matter halos

abstract:
  We present a detailed non-spherical modeling of dark matter halos on the
basis of a careful analysis of state-of-the art N-body simulations. The fitting
formulae presented here form a complete and accurate description of the
triaxial density profiles of halos in Cold Dark Matter(CDM) models. This
modeling allows us to quantitatively discuss implications for shape
observations of galactic and cluster halos. The predictions of the concordance
$\lambda$CDM model are confronted with the shape observations from the Milky
Way to X-ray clusters.


title: Detailed Composition of Starts in Dwarf Spheroidal Galaxies

abstract:
  A refereed review paper which covers high resolution abundances in dSph
galaxies.


title:
The H2CO abundance in the inner warm regions of low mass protostellar
  envelopes

abstract:
  We present a survey of the formaldehyde emission in a sample of eight Class 0
protostars obtained with the IRAM and JCMT telescopes. The data have been
analyzed with three different methods with increasing level of sophistication.
We first analyze the observed emission in the LTE approximation, and derive
rotational temperatures between 11 and 40 K, and column densities between 1 and
20 x 10^13 cm^-2. Second, we use a LVG code and derive larger kinetic
temperatures, between 30 and 90 K, consistent with subthermally populated
levels and densities from 1 to 6 x 10^5 cm^-3. The column densities from the
LVG modeling are within a factor of 10 with respect to those derived in the LTE
approximation. Finally, we analyze the observations based upon detailed models
for the envelopes surrounding the protostars, using temperature and density
profiles previously derived from continuum observations. We approximate the
formaldehyde abundance across the envelope with a jump function, the jump
occurring when the dust temperature reaches 100 K, the evaporation temperature
of the grain mantles. The observed formaldehyde emission is well reproduced
only if there is a jump, more than two orders of magnitude, in four sources. In
the remaining four sources the data are consistent with a formaldehyde
abundance jump, but the evidence is more marginal (~2 sigma). The inferred
inner H2CO abundance varies between 1 x 10^-8 and 6 x 10^-6. We discuss the
implications of these jumps for our understanding of the origin and evolution
of ices in low mass star forming regions. Finally, we give predictions for the
submillimeter H2CO lines, which are particularly sensitive to the abundance
jumps.


title:
The impact of spheroid stars for Macho microlensing surveys of the
  Andromeda Galaxy

abstract:
  The Andromeda Galaxy (M31) is an important test case for a number of
microlensing surveys looking for massive compact halo objects (Machos). A
long-standing theoretical prediction is that the high inclination of the M31
disk should induce an asymmetry in the spatial distribution of M31 Macho
events, whilst the distribution of variable stars and microlensing events in
the M31 disk should be symmetric. We examine the role of stars in the M31
visible spheroid as both lenses and sources to microlensing events. We compute
microlensing event number density maps and estimate pixel-lensing rates and
event durations for three-component models of M31 which are consistent with the
observed rotation curve, surface brightness profile and dynamical mass
estimates. Three extreme models are considered: a massive spheroid model; a
massive disk model; and a massive Macho halo model. An important consequence of
the spheroid is that, even if Machos are absent in M31, an asymmetric spatial
signature is still generally expected from stellar lensing alone. The relative
mass-to-light ratio of the spheroid and disk populations controls which of
these signatures dominates the overall stellar spatial distribution. We find
that the inclusion of the spheroid weakens the M31 Macho spatial asymmetry by
about 20-30% over a disk-only asymmetry for the models considered. We also find
for our models that Machos dominate over most of the far disk provided they
contribute at least ~25% of the halo dark matter density. The presence of the
spheroid also has beneficial consequences for M31 lensing surveys. The stellar
asymmetry is likely to be important in distinguishing between a spheroidal
Macho halo or a highly flattened halo or dark matter dominated disk, since
spatial asymmetries of opposing signs are expected in these cases. (Abridged)


title: High energy emission from microquasars

abstract:
  The microquasar phenomenon is associated with the production of jets by X-ray
binaries and, as such, may be associated with the majority of such systems. In
this chapter we briefly outline the associations, definite, probable, possible,
and speculative, between such jets and X-ray, gamma-ray and particle emission.


title:
Cyclic evolution and reversal of the solar magnetic field. I. The
  large-scale magnetic fields

abstract:
  On the base of the solar magnetic field measurements obtained in Stanford in
1976--2003 the properties of the cyclic evolution of the large-scale magnetic
field are investigated. Some regularities are found in longitudinal and
latitudinal evolution of the magnetic field in cycles 21, 22 and 23. The cyclic
development of the large-scale magnetic field can be divided into two main
phases. The phase I, which includes a period approximately from two years
before and until three years after the maximum of the solar cycle, is studied
in detail. It is found that before the reversal of the large-scale magnetic
field the neutral line of the magnetic field in antipodal longitudinal
intervals shifts from the equator to opposite directions in cycles 21 and 22,
but not in cycle 23. During the sign reversal of the large-scale magnetic field
in cycles 21 and 22 in the antipodal longitudinal intervals the magnetic field
of opposite polarity is observed in all latitudes, thereby forming an
equatorial dipole. After the magnetic field reversal a longitudinal oscillation
of the magnetic neutral line with regard to the equator takes place, which has
a period about 2 years and damps to the minimum of the 11-year cycle. The
intervening longitudinal intervals of the large-scale magnetic field correspond
to positions of the active longitudes of sunspot activity, thus indicating a
close connection of the large-scale and the local magnetic fields. In evolution
of the large-scale magnetic field a periodicity with period $1.23\pm0.16$ year
is revealed, which is close to the period found by helioseismological methods
in variations of the solar rotation near the tachocline.


title:
NGC6822: short period variable stars, stellar population and distance
  scale

abstract:
  Results are presented on a study of the short period variable stars in the
dwarf irregular galaxy NGC6822. We observed an almost uniformely populated
classical instability strip from the Horizontal Branch up to the Classical
Cepheids region. The main goal we achieved from the analysis of the faint
sample is the first detection of RR Lyrae stars in this galaxy.


title: Axion Bremsstrahlung

abstract:
  A new mechanism of cosmic axion production is proposed: axion bremsstrahlung
from collisions of straight global strings. This effect is of the second order
in the axion coupling constant, but the resulting cosmological estimate is
likely to be of the same order as that corresponding to radiation from
oscillating string loops. This may lead to a further restriction on the axion
window.


title: Phase cross-correlation of the WMAP ILC map and foregrounds

abstract:
  We present a circular cross-correlation tests for the phases of the Internal
Linear Combination Map (ILC) and {\it WMAP}'s foregrounds for all K--W
frequency bands at the range of multipoles $\ell\le 50$. We have found
significant deviations from the expected Poissonian statistics for the ILC and
the foregrounds phases. Our analysis shows that the low multipole range of the
ILC power spectrum contains some of the foregrounds residues.


title:
Stellar populations and their kinematics from high and medium resolution
  spectra: mixed inversions

abstract:
  We present inversion techniques aiming at recovering the stellar content
(age, metallicity, extinction) and kinematics of a stellar population from its
absorption line spectrum. These techniques use new synthetic high resolution
spectra produced by PEGASE_HR and minimization algorithms. Application to SDSS
data and to a simulated disc-bulge system are presented as examples.


title:
Expected masses of merging compact object binaries observed in
  gravitational waves

abstract:
  We use the well tested StarTrack binary population synthesis code to examine
the properties of the population of compact object binaries. We calculate the
distribution of masses and mass ratios taking into account weights introduced
by observability in gravitational waves during inspiral. We find that in the
observability weighted distribution of double neutron star binaries there are
two peaks: one for nearly equal mass systems, and one for the systems
consisting of a low and a high mass neutron star, $q=0.6-0.7$. The
observability weighted distribution of black hole neutron star binaries is
concentrated on the systems with the mass ratio $q=0.3-0.5$, while for the
double black hole binaries the observability weighted distribution is dominated
by the massive, nearly equal mass binaries with $q>0.7$.


title:
Distance Scale, Variable Stars and Stellar Populations in Local Group
  Galaxies

abstract:
  We present an overview of our study of the short period variable stars in the
Large Magellanic Cloud, and in the dwarf galaxies Fornax, Leo I, and NGC 6822.
Light curves are presented for RR Lyrae stars, Anomalous Cepheids and, for the
first time, for Dwarf Cepheids in the field and in the globular cluster #3 of
the Fornax galaxy.


title:
Mid-infrared emission of galactic nuclei: TIMMI2 versus ISO observations
  and models

abstract:
  We investigate the mid-infrared radiation of galaxies that are powered by a
starburst or by an AGN. For this end, we compare the spectra obtained at
different spatial scales in a sample of infrared bright galaxies. ISO
observations which include emission of the nucleus as well as most of the host
galaxy are compared with TIMMI2 spectra of the nuclear region. We find that ISO
spectra are generally dominated by strong PAH bands. However, this is no longer
true when inspecting the mid-infrared emission of the pure nucleus. Here PAH
emission is detected in starbursts whereas it is significantly reduced or
completely absent in AGNs. A physical explanation of these new observational
results is presented by examining the temperature fluctuation of a PAH after
interaction with a photon. It turns out that the hardness of the radiation
field is a key parameter for quantifying the photo-destruction of small grains.
Our theoretical study predicts PAH evaporation in soft X-ray environments.
Radiative transfer calculations of clumpy starbursts and AGN corroborate the
observational fact that PAH emission is connected to starburst activity whereas
PAHs are destroyed near an AGN. The radiative transfer models predict for
starbursts a much larger mid-infrared size than for AGN. This is confirmed by
our TIMMI2 acquisition images: We find that the mid-infrared emission of
Seyferts is dominated by a compact core while most of the starbursts are
spatially resolved.


title: A search for LSB dwarf galaxies in various environments

abstract:
  The varying dwarf galaxy populations in different environments poses a
problem for Cold Dark Matter (CDM) hierarchical clustering models. In this
paper we present results from a survey conducted in different environments to
search for low surface brightness (LSB) dwarf galaxies.


title:
Constraining Binary Evolution with Gravitational Wave Measurements of
  Chirp Masses

abstract:
  Using the StarTrack binary population synthesis code we investigate the
properties of population of compact object binaries. Taking into account the
selection effects we calculate the expected properties of the observed
binaries.We analyze possible constraints on the stellar evolution models and
find that an observed sample of about one hundred mergers will yield strong
constraints on the binary evolution scenarios.


title: The Density Profile of Massive Galaxy Clusters from Weak Lensing

abstract:
  We use measurements of weak gravitational shear around a sample of massive
galaxy clusters at z = 0.3 to constrain their average radial density profile.
Our results are consistent with the density profiles of CDM halos in numerical
simulations and inconsistent with simple models of self-interacting dark
matter. Unlike some other recent studies, we are not probing the scales where
the baryonic mass component becomes dynamically important, and so our results
should be directly comparable to CDM N-body simulations.


title: Compact object mergers as progenitors of short bursts

abstract:
  Compact object mergers are possible progenitors of short bursts. We analyze
properties of compact object mergers using the StarTrack population synthesis
code, and find that the double neutron star population is dominated by short
lived systems, thus they merge within host galaxies, while black hole neutron
star binaries merge outside of the host galaxies. We summarize the differences
between these two types of mergers.


title:
A physicist's view of stellar dynamics: dynamical instability of stellar
  systems

abstract:
  I argue that the widely adopted framework of stellar dynamics survived since
1940s, is not fitting the current knowledge on non-linear systems. Borrowed
from plasma physics when several fundamental features of perturbed non-linear
systems were unknown, that framework ignores the difference in the role of
perturbations in two different classes of systems, in plasma with Debye
screening and gravitating systems with no screening. Now, when the
revolutionary role of chaotic effects is revealed even in planetary dynamics
i.e. for nearly integrable systems, one would expect that for stellar systems,
i.e. non-integrable systems, their role have to be far more crucial. Indeed,
ergodic theory tools already enabled to prove that spherical stellar systems
are exponentially instable due to N-body interactions, while the two-body
encounters, contrary to existing belief, are not the dominating mechanism of
their relaxation. Chaotic effects distinguish morphological and other
properties of galaxies. Using the Ricci curvature criterion, one can also show
that a central massive object (nucleus) makes the N-body gravitating system
more instable (chaotic), while systems with double nuclei are even more
instable than those with a single one.


title: Cosmological principle and honeycombs

abstract:
  We present the possibility that the gravitational growth of primordial
density fluctuations leads to what can be considered a week version of the
cosmological principle. The large scale mass distribution associated with this
principle must have the geometrical structures known as a regular honeycombs.
We give the most important parameters that characterize the honeycombs
associated with the closed, open, and flat FLRW models. These parameters can be
used to determine by means of observations which is the appropriate honeycomb.
For each of these honeycombs, and for a nearly flat universe, we have
calculated the probability that a randomly placed observer could detect the
honeycomb as a function of the density parameters.


title:
Chandra X-ray Observations of NGC 4258: Iron Absorption Lines from the
  Nucleus

abstract:
  We report sub-arcsecond resolution X-ray imaging spectroscopy of the low
luminosity active galactic nucleus of NGC 4258 and its immediate surroundings
with the Chandra X-ray Observatory. NGC 4258 was observed four times, with the
first two observations separated by one month, followed over a year later by
two consecutive observations. The spectrum of the nucleus is well described by
a heavily absorbed, hard X-ray power law of variable luminosity, plus a
constant, thermal soft X-ray component. We do not detect an iron K alpha
emission line with the upper limit to the equivalent width of a narrow, neutral
iron line ranging between 94 and 887 eV (90% confidence) for the different
observations. During the second observation on 2000-04-17, two narrow
absorption features are seen with >99.5% confidence at ~6.4 keV and ~6.9 keV,
which we identify as resonant absorption lines of Fe XVIII - Fe XIX K alpha and
Fe XXVI K alpha, respectively. In addition, the 6.9 keV absorption line is
probably variable on a timescale of ~6000 sec. The absorption lines are
analyzed through a curve of growth analysis, which allows the relationship
between ionic column and kinematic temperature or velocity dispersion to be
obtained for the observed equivalent widths. We discuss the properties of the
absorbing gas for both photo and collisionally ionized models. Given that the
maser disk is viewed at an inclination i = 82 degrees, the gas responsible for
the 6.9 keV absorption line may be in an inner disk, a disk-wind boundary layer
or be thermal gas entrained at the base of the jet. The gas which gives rise to
the photoelectric absorption may be the same as that which causes the 6.4 keV
Fe K alpha absorption provided that the gas has a bulk velocity dispersion of a
few thousand km/s. (Abstract abridged).


title: Molecular Gas Chemistry in Starbursts and AGN

abstract:
  We present the main results of an extragalactic survey aiming to study the
chemistry of molecular gas in a limited sample of starburst galaxies (SB) and
AGN hosts. Observations have been carried out with the IRAM 30m telescope and
the Plateau de Bure Interferometer (PdBI). The high resolution/sensitivity of
the PdBI has made possible to obtain high quality images of the galaxies using
specific molecular gas tracers of Shock Chemistry, Photon Dominated Regions
(PDR) and X-ray Dominated Regions (XDR). The occurrence of large-scale shocks
and the propagation of PDR chemistry in starbursts can be studied. We also
discuss the onset of XDR chemistry in AGN.


title: A Search for X-Ray Flashes with XMM-Newton

abstract:
  We searched for X-ray flashes (XRFs) -- which we defined as ~10s duration
transient X-ray events observable in the 0.4-15 keV passband -- in fields
observed using XMM-Newton with the EPIC/pn detector. While we find two
non-Poissonian events, the astrophysical nature of the events is not confirmed
in fully simultaneous observations with the EPIC/MOS detectors, and we conclude
that the events are anomalous to the EPIC/pn detector. We find a 90% upper
limit on the number of flashes per sky per year at two different incoming flash
fluxes: 4.0x10^9 events / sky / year for a flux of 7.1x10^-13 erg / cm^2 / s
and 6.8x10^7 events / sky / year for 1.4x10^-11 erg / cm^2 / s. These limits
are consistent with an extrapolation from the BeppoSAX/WFC XRF rate at much
higher fluxes (about a factor of 10^5), assuming an homogenous population, and
with a previous, more stringent limit derived from ROSAT pointed observations.


title: Water vapor in the starburst galaxy NGC 253: A new nuclear maser?

abstract:
  22 GHz water vapor emission was observed toward the central region of the
spiral starburst galaxy NGC 253. Monitoring observations with the 100-m
telescope at Effelsberg and measurements with the BnC array of the VLA reveal
three distinct velocity components, all of them blueshifted with respect to the
systemic velocity. The main component arises from a region close to the
dynamical center and is displaced by <1 arcsec from the putative nuclear
continuum source. The bulk of this maser component is spread over an area not
larger than 70 x 50 mas. Its radial velocity may be explained by masing gas
that is part of a nuclear accretion disk or of a counterrotating kinematical
subsystem or by gas that is entrained by the nuclear superwind or by an
expanding supernova shell. A weaker feature, located 5 arcsec to the northeast,
is likely related to an optically obscured site of massive star formation.


title: Chemical Composition of the Intracluster Medium

abstract:
  Clusters of galaxies are massive enough to be considered representative
samples of the Universe, and to retain all of the heavy elements synthesized in
their constituent stars. Since most of these metals reside in hot plasma, X-ray
spectroscopy of clusters provides a unique and fundamental tool for studying
chemical evolution. I review the current observational status of X-ray
measurements of the chemical composition of the intracluster medium, and its
interpretation in the context of the nature and history of star and galaxy
formation processes in the Universe. I provide brief historical and
cosmological contexts, an overview of results from the mature ASCA observatory
database, and new results from the Chandra and XMM-Newton X-ray observatories.
I conclude with a summary of important points and promising future directions
in this rapidly growing field.


title: Chemical Evolution in Hierarchical Clustering Scenarios

abstract:
  We present first results of an implementation of chemical evolution in a
cosmological hydrodynamical code, focusing the analysis on the effects of
cooling baryons according to their metallicity. We found that simulations with
primordial cooling can underestimate the star formation rate from $z < 3$ and
by up to $\approx 20 %$. We constructed simulated spectra by combining the star
formation and chemical history of galactic systems with spectra synthesis
models and assess the impact of chemical evolution on the energy distribution.


title: Chemical Abundances and the Hierarchical Clustering

abstract:
  We studied the chemical enrichment of the interstellar medium and stellar
population of the building blocks of current typical galaxies in the field, in
cosmological hydrodynamics simulations. The simulations include detail modeling
of chemical enrichment by SNIa and SNII. In our simulations the metal missing
problem is caused by chemical elements being locked upon in the central regions
(or bulges) mainly, in stars.
  Supernova energy feedback could help to reduce this concentration by
expelling metals to the intergalactic medium.


title: Triggering star formation by galaxy-galaxy interactions

abstract:
  We analyzed the effects of having a close companion on the star formation
activity of galaxies in 8K galaxy pair catalog selected from the 2dFGRS. We
found that, statistically, galaxies with $r_{\rm p} < 25 {\rm h^{-1}}$ kpc and
$\Delta V < 100 {\rm km/s}$ have enhanced star formation with respect to
isolated galaxies with the same luminosity and redshift distribution. Our
results suggest that the physical processes at work during tidal interactions
can overcome the effects of environment, expect in dense regions.


title: Results from a diffuse intracluster light survey

abstract:
  We give an update of our ongoing survey for intracluster light (ICL), in a
sample of distant Abell clusters. We find that the amount of intracluster
starlight is comparable to that seen in nearby clusters, and that tidal debris
appears to be common.


title: First results from a Chandra survey of the 'Bar' region of the SMC

abstract:
  We present the first results from a Chandra survey of the central region of
the Small Magellanic Cloud. We detect a total of 122 sources down to a limiting
luminosity of ~4.3x10^{33} erg\s (corrected for Galactic N_{H}), which is ~10
times lower than in any previous survey of the SMC. We identify 20 candidate
transient sources: eighteen previously known sources in this area which are not
detected in our observations, and two new bright sources. The spectral
parameters of the brightest sources indicate that they are X-ray binary
pulsars. The high spatial resolution of Chandra allows us to initially identify
optical counterparts for 35 sources, 13 of which are new identifications.


title: Cessation of X-ray Pulsation of GX 1+4

abstract:
  We report results from our weekly monitoring campaign on the X-ray pulsar GX
1+4 with the {\em Rossi X-ray Timing Explorer} satellite. The spin-down trend
of GX 1+4 was continuing, with the pulsar being at its longest period ever
measured (about 138.7 s). At the late stage of the campaign, the source entered
an extended faint state, when its X-ray (2-60 keV) flux decreased significantly
to an average level of $\sim 3 \times 10^{-10} ergs cm^{-2} s^{-1}$. It was
highly variable in the faint state; the flux dropped to as low as $\sim 3
\times 10^{-11} ergs cm^{-2} s^{-1}$. In several observations during this
period, the X-ray pulsation became undetectable. We can, therefore, conclude
conservatively that the pulsed fraction, which is normally $\gtrsim$ 70%
(peak-to-peak), must have decreased drastically in those cases. This is very
similar to what was observed of GX 1+4 in 1996 when it became similarly faint
in X-ray. In fact, the flux at which the cessation of X-ray pulsation first
occurred is nearly the same as it was in 1996. We suggest that we have, once
again, observed the propeller effect in GX 1+4, a phenomenon that is predicted
by theoretical models of accreting X-ray pulsars.


title:
A Resolved Circumstellar Disk around the Herbig Ae Star HD 100546 in the
  Thermal Infrared

abstract:
  We present mid-infrared nulling interferometric and direct imaging
observations of the Herbig Ae star HD 100546 obtained with the Magellan I
(Baade) 6.5 m telescope. The observations show resolved circumstellar emission
at 10.3, 11.7, 12.5, 18.0, and 24.5 microns. Through the nulling observations
(10.3, 11.7 and 12.5 microns), we detect a circumstellar disk, with an
inclination of 45 +- 15 degrees with respect to a face-on disk, a semimajor
axis position angle of 150 +- 10 degrees (E of N), and a spatial extent of
about 25 AU. The direct images (18.0 and 24.5 microns) show evidence for cooler
dust with a spatial extent of 30-40 AU from the star. The direct images also
show evidence for an inclined disk with a similar position angle as the disk
detected by nulling. This morphology is consistent with models in which a
flared circumstellar disk dominates the emission. However, the similarity in
relative disk size we derive for different wavelengths suggests that the disk
may have a large inner gap, possibly cleared out by the formation of a giant
protoplanet. The existence of a protoplanet in the system also provides a
natural explanation for the observed difference between HD 100546 and other
Herbig Ae stars.


title: The Selection of RR Lyrae Stars Using Single-epoch Data

abstract:
  We utilize a complete sample of RR Lyrae stars discovered by the QUEST survey
using light curves to design selection criteria based on SDSS colors. Thanks to
the sensitivity of the u-g color to surface gravity and of g-r color to
effective temperature, and to the small photometric errors (~0.02 mag)
delivered by SDSS, RR Lyrae stars can be efficiently and robustly recognized
even with single-epoch data. In a 100% complete color-selected sample, the
selection efficiency (the fraction of RR Lyrae stars in the candidate sample)
is 6%, and, by adjusting color cuts, it can be increased to 10% with a
completeness of 80%, and to 60% with 28% completeness. Such color selection
produces samples that are sufficiently clean for statistical studies of the
Milky Way's halo substructure, and we utilize it to select 3,643 candidate RR
Lyrae stars from SDSS Data Release 1. We demonstrate that this sample recovers
known clumps of RR Lyrae stars associated with the Sgr dwarf tidal tail, and
Pal 5 globular cluster, and use it to constrain the halo substructure away from
the Sgr dwarf tidal tail. These results suggest that it will be possible to
study the halo substructure out to ~70 kpc from the Galactic Center in the
entire area imaged by the SDSS, and not only in the multiply observed regions.


title: Counts of Low-redshift SDSS Quasar Candidates

abstract:
  We analyze the counts of low-redshift quasar candidates selected using
nine-epoch SDSS imaging data. The co-added catalogs are more than 1 mag deeper
than single-epoch SDSS data, and allow the selection of low-redshift quasar
candidates using UV-excess and also variability techniques. The counts of
selected candidates are robustly determined down to g=21.5. This is about 2
magnitudes deeper than the position of a change in the slope of the counts
reported by Boyle et al. (1990, 2000) for a sample selected by UV-excess, and
questioned by Hawkins & Veron (1995), who utilized a variability-selected
sample. Using SDSS data, we confirm a change in the slope of the counts for
both UV-excess and variability selected samples, providing strong support for
the Boyle et al. results.


title: NGC 4261 and NGC 4697: rejuvenated elliptical galaxies

abstract:
  Chandra images present evidence for a non-uniform spatial distribution of
discrete X-ray sources in the elliptical galaxy NGC 4261. This non-uniform
distribution is inconsistent with the optical morphology of NGC 4261 at greater
than a 99.9% confidence level. Similar evidence is seen in one more elliptical
galaxy (NGC 4697; 98% confidence level) out of five cases we investigated. NGC
4261 and NGC 4697 have old stellar populations (9-15 Gyrs) and fine structure
parameters of 1 and 0 respectively, suggesting no recent merging activity. On
the basis of simulations of galaxy interactions, we propose that the X-ray
sources responsible for the non-uniform distribution are associated with young
stellar populations, related to the rejuvenating fall-back of material in tidal
tails onto a relaxed merger remnant, or shock induced star-formation along the
tidal tails.


title: Studying the populations of our Galaxy using the kinematics of sdB stars

abstract:
  We have analysed the kinematics of a sample of 114 hot subdwarf stars, for
2/3 of which we present new proper motions, spectroscopic and photometric data.
The vast majority of the stars show a kinematic behaviour that is similar to
that of Thick Disk stars. Some stars have velocities rather fitting to solar,
i.e. Thin Disk, kinematics. 16 objects have orbital velocities which differ
considerably from those of Disk stars. These are members of the Galactic Halo.
We analysed the velocity dispersions and calculated orbits. Most stars feature
orbits with disk character (eccentricity <= 0.5), a few reach far above the
Galactic plane and have very eccentric orbits (ecc >= 0.7). The intermediate
eccentricity range is poorly populated. This indicates that the (Thick) Disk
and the Halo are kinematically disjunct. Plotting a histogram of the orbit data
points along z leads to the z-distance probability distribution of the star;
doing this for all stars leads to the z-distance probability distribution of
the sample. The logarithmic histogram shows two slopes, each representing the
scale height of a population. The disk component has a scale height of 0.9
(0.1) kpc, which is consistent with earlier results and is similar to that of
the Thick Disk. The other slope represents a component with a scale height ~7
kpc, a much flatter gradient than for the disk component. This shows that the
vast majority of the sdBs are Disk stars, but a Halo minority is present, too.
The kinematic history and population membership of the sdB stars on the whole
is different from that of the cooler HBA stars, which are predominantly or even
exclusively Halo objects. This leads to the question, whether the Halo sdB
stars are of similar origin as the HBAs, or whether their kinematical behaviour
possibly represents another origin, such as infalling stellar aggregates.


title:
Quasar Radio Dichotomy: Two Peaks, or not Two Peaks, that is the
  Question

abstract:
  Recent claims by Ivezic et al. (2002) that the distribution of the
radio-to-optical flux ratio, R, for quasars is bimodal (the so-called quasar
radio dichotomy) were questioned on statistical grounds by Cirasuolo et al.
(2003). We apply the approach suggested by Cirasuolo et al. to a sample of
\~10,000 objects detected by SDSS and FIRST, and find support for the quasar
radio dichotomy. The discrepancy between the claims by Cirasuolo et al. and the
results presented here is most likely because 1) the ~100 times larger sample
based on two homogeneous surveys that is used here allows a direct
determination of the R distribution, rather than relying on indirect inferences
based on Monte Carlo simulations of several heterogeneous surveys 2) the
accurate SDSS colors and redshift information allow robust determination of the
K-correction for R, which, if unaccounted for, introduces significant scatter
that masks the intrinsic properties of the quasar R distribution.


title: New abundances of planetary nebulae in the Galactic Bulge

abstract:
  New observations and derived chemical abundances are reported for a sample of
57 bulge planetary nebulae (PN). Together with our previous results, a total of
over a hundred objects have been analyzed, which constitute one of the largest
samples of bulge nebulae studied under homogeneous conditions, including
equipment and reduction procedures. In general, our data show a good agreement
with some recent results in the literature, in the sense that the average
abundances of bulge PN are similar to those from disk objects, however showing
a larger dispersion.


title: A Map of the Universe

abstract:
  We have produced a new conformal map of the universe illustrating recent
discoveries, ranging from Kuiper belt objects in the Solar system, to the
galaxies and quasars from the Sloan Digital Sky Survey. This map projection,
based on the logarithm map of the complex plane, preserves shapes locally, and
yet is able to display the entire range of astronomical scales from the Earth's
neighborhood to the cosmic microwave background. The conformal nature of the
projection, preserving shapes locally, may be of particular use for analyzing
large scale structure. Prominent in the map is a Sloan Great Wall of galaxies
1.37 billion light years long, 80% longer than the Great Wall discovered by
Geller and Huchra and therefore the largest observed structure in the universe.


title: Alternatives to Dark Matter (?)

abstract:
  It has long been known that Newtonian dynamics applied to the visible matter
in galaxies and clusters does not correctly describe the dynamics of those
systems. While this is generally taken as evidence for dark matter it is in
principle possible that instead Newtonian dynamics (and with it General
Relativity) breaks down in these systems. Indeed there have been a number of
proposals as to how standard gravitational dynamics might be modified so as to
correctly explain galactic dynamics without dark matter. I will review this
general idea (but focus on ``MOdified Newtonian Dynamics'', or ``MOND''), and
discuss a number of ways alternatives to dark matter can be tested and (in many
cases) ruled out.


title: On the angular momentum of the neutron star

abstract:
  It is shown that the mass loss due to rotation-driven hydrodynamical
instability during the catastrophic collapse of the star is small. Neutron star
is formed with a large rotational kinetic energy and the spin-down takes place
in the following life of neutron star as a pulsar.


title: On the Origin of Nuclear Star Clusters in Late Type Spiral Galaxies

abstract:
  A large fraction of bulgeless disk galaxies contain young compact stellar
systems at their centers, in spite of the local gravitational stability of
these disks. We evaluate two contrasting hypotheses for the origin of the
nuclear star clusters in late-type disk galaxies. The clusters could not have
migrated from distant eccentric locations in the disk. Instead they must have
formed in situ, requiring radial transport of gas toward the center of the
disk. This transport could be a consequence of the development of the
magnetorotational instability in the differentially rotating warm neutral
medium. We evaluate the rate of gas transport into the disk center and find
that it is sufficient to support continuous star formation in that location.
Enhanced stellar surface brightness in the inner few hundred parsecs and the
formation of a compact stellar system in the central few parsecs are
unavoidable in dark matter halos with divergent density profiles. We illustrate
our conclusions on a model of the nearest late-type disk galaxy M33.


title:
Changes in the X-ray Emission from the Magnetar Candidate 1E 2259+586
  during its 2002 Outburst

abstract:
  (abridged) An outburst of more than 80 individual bursts, similar to those
seen from Soft Gamma Repeaters (SGRs), was detected from the Anomalous X-ray
Pulsar (AXP) 1E 2259+586 in 2002 June. Coincident with this burst activity were
gross changes in the pulsed flux, persistent flux, energy spectrum, pulse
profile and spin down of the underlying X-ray source. We present RXTE and
XMM-Newton observations of 1E 2259+586 that show the evolution of the
aforementioned source parameters during and following this episode.
Specifically, we observe an X-ray flux increase by more than an order of
magnitude having two distinct components. The first component is linked to the
burst activity and decays within ~2 days during which the energy spectrum is
considerably harder than during the quiescent state of the source. The second
component decays over the year following the glitch according to a power law in
time with an exponent -0.22 +/- 0.01. The pulsed fraction decreased initially
to ~15% RMS, and the pulse profile changed significantly during the outburst. A
glitch was observed in 1E 2259+586 that preceded the observed burst activity. A
fraction of the glitch (~19%) recovered, although the recovery was not purely
exponential. An exponential rise of ~20% of the frequency jump with a time
scale of ~14 days results in a significantly better fit to the data, however,
contamination from a systematic drift in the phase of the pulse profile cannot
be excluded. The long-term post-glitch spin-down rate decreased in magnitude
relative to the pre-glitch value. A comparison with SGR outburst properties, a
physical interpretation of the results, and implications on the number of
magnetar candidates in our Galaxy are discussed.


title:
The Inner Structure of LCDM Halos II: Halo Mass Profiles and LSB
  Rotation Curves

abstract:
  We use a set of high-resolution cosmological N-body simulations to
investigate the inner mass profile of galaxy-sized cold dark matter (CDM)
halos. These simulations extend the thorough numerical convergence study
presented in Paper I of this series (Power et al. 2003), and demonstrate that
the mass profile of CDM halos can be robustly estimated beyond a minimum
converged radius of order r_conv ~ 1 kpc/h in our highest resolution runs. The
density profiles of simulated halos become progressively shallow from the
virial radius inwards, and show no sign of approaching a well-defined power-law
behaviour near the centre. At r_conv, the logarithmic slope of the density
profile is steeper than the asymptotic \rho \propto r^-1 expected from the
formula proposed by Navarro, Frenk, and White (1996), but significantly
shallower than the steeply divergent \rho \propto r^-1.5 cusp proposed by Moore
et al. (1999). We perform a direct comparison of the spherically-averaged dark
matter circular velocity (V_c) profiles with rotation curves of low surface
brightness (LSB) galaxies from the samples of de Blok et al. (2001), de Blok
and Bosma (2002), and Swaters et al. (2003). Most (about two-thirds) LSB
galaxies in this dataset are roughly consistent with CDM halo V_c profiles.
However, about one third of LSBs in these samples feature a sharp transition
between the rising and flat part of the rotation curve that is not seen in the
V_c profiles of CDM halos. This discrepancy has been interpreted as excluding
the presence of cusps, but we argue that it might simply reflect the difference
between circular velocity and gas rotation speed likely to arise in gaseous
disks embedded within realistic, triaxial CDM halos.


title: chi^2 and Linear Fits

abstract:
  The mathematics of linear fits is presented in covariant form. Topics
include: correlated data, covariance matrices, joint fits to multiple data
sets, constraints, and extension of the formalism to non-linear fits. A brief
summary at the end provides a convenient crib sheet. These are somewhat
amplified notes from a 90 minute lecture in a first-year graduate course. None
of the results are new. They are presented here because they do not appear to
be elsewhere available in compact form.


title: OGLE small amplitude red giant variables in the Galactic Bar

abstract:
  Among over 200,000 Galactic Bulge variable stars in the public domain OGLE
catalogue, we found over 15,000 red giant variables following two well defined
period -- amplitude relations. The periods are in the range 10 < P < 100 days,
and amplitudes in the range 0.005 < A < 0.13 mag in I-band. The variables cover
a broad range of reddening corrected colours, 1 < (V-I)_0 < 5, and a fairly
narrow range of extinction corrected apparent magnitudes, 10.5 < I_0 < 13 . A
subset of variables (type A) has a rms scatter of only 0.44 mag. The average
magnitudes for these stars are well correlated with the Galactic longitude, and
vary from I_{k,0} = 11.82 for l = +8 deg to I_{k,0} = 12.07 for l = -5 deg,
clearly indicating that they are located in the Galactic Bar. Most variables
have several oscillation periods.


title:
X-Ray Constraints on Dark Matter in Galaxy Clusters and Elliptical
  Galaxies: A View from Chandra and XMM

abstract:
  I review constraints on the radial density profiles and ellipticities of the
dark matter obtained from recent X-ray observations with Chandra and XMM of
elliptical galaxies and galaxy clusters and discuss their implications,
especially for the self-interacting dark matter model.


title:
Mid-Infrared Imaging of the Post-AGB Star AC Herculis with the MMT
  Adaptive Optics System

abstract:
  We utilized the MMT's unique deformable secondary adaptive optics system to
produce high-resolution (FWHM=0.3"), very high Strehl mid-infrared (9.8, 11.7 &
18 micron) images of the post-AGB star AC Her. The very high (98+/-2%) Strehls
achieved with Mid-IR AO led naturally to an ultra-stable PSF independent of
airmass, seeing, or location on the sky. We find no significant difference
between AC Her's morphology and our unresolved PSF calibration stars (mu UMa &
alpha Her) at 9.8, 11.7, & 18 microns. Our current observations do not confirm
any extended Mid-IR structure around AC Her. These observations are in conflict
with previously reported Keck (seeing-limited) 11.7 and 18 micron images which
suggested the presence of a resolved ~0.6" edge-on circumbinary disk. We
conclude that AC Her has no extended Mid-IR structure on scales greater than
0.2" (R<75 AU). These first results of Mid-IR AO science are very encouraging
for future high accuracy Mid-IR imaging with this technique.


title: Case Studies of Mass Transfer and Star Formation in Galaxy Collisions

abstract:
  The amount, timing and ultimate location of mass transfer and induced star
formation in galaxy collisions are sensitive functions of orbital and galaxy
structural parameters. I discuss the role of detailed case studies and describe
the results for two systems, Arp 284 and NGC 2207/IC 2163, that have been
studied with both multiwaveband observations, and detailed dynamical models.
The models yield the mass transfer and compressional histories of the
encounters and the ``probable causes'' or triggers of individual star-forming
regions.


title: Beta Cephei and SPB stars in the Large Magellanic Cloud

abstract:
  This is a progress report of the study of pulsating main-sequence stars in
the LMC. Using the OGLE-II photometry supplemented by the MACHO photometry, we
find 64 Beta Cephei stars in the LMC. Their periods are generally much longer
than observed in stars of this type in the Galaxy (the median value is 0.27 d
compared with 0.17 d in the Galaxy). In 20 stars with short periods
attributable to the Beta Cephei-type instability, we also find modes with
periods longer than 0.4 d. They are likely low-order g modes, which means that
in these stars both kinds of variability, Beta Cephei and SPB, are observed. We
also show examples of the multiperiodic SPB stars in the LMC, the first beyond
our Galaxy.


title: Some Effects of Galaxy Collisions in a Cluster ICM

abstract:
  We present preliminary results of numerical modeling of the combined effects
of ICM stripping and galaxy collisions on galaxies in clusters. We use the
Hydra adaptive mesh, P3M + SPH code of Couchman et al. (1995). Generally, the
formation of extended tidal and splash structures in galaxy interactions will
facilitate ram pressure stripping. ICM compression of massive clouds stripped
from tails and plumes may produce significant populations of free-floating star
clusters or dwarf galaxies.


title: Results from the South Pole InfraRed EXplorer Telescope

abstract:
  The SPIREX telescope, located at the Amundsen-Scott South Pole Station, was a
prototype system developed to exploit the excellent conditions for IR observing
at the South Pole. Observations over two winter seasons achieved remarkably
deep, high-resolution, wide-field images in the 3-5um wavelength regime.
Several star forming complexes were observed, including NGC 6334, Chamaeleon I,
eta Chamaeleontis, the Carina Nebula, 30 Doradus, RCW 57, RCW 38, as well as
the Galactic Centre. Images were obtained of lines at 2.42um H2, 3.29um PAH and
4.05um Bra, as well as 3.5um L-band and 4.7um M-band continuum emission. These
data, combined with near-IR, mid-IR, and radio continuum maps, reveal the
environments of these star forming sites, as well as any protostars lying
within them. The SPIREX project, its observing and reduction methods, and some
sample data are summarized here.


title: Multiwavelength Observations of Galactic Winds: Near and Far

abstract:
  This paper provides a critical discussion of the observational evidence for
winds in our own Galaxy, in nearby star-forming and active galaxies, and in the
high-redshift universe. The implications of galactic winds on the formation and
evolution of galaxies and the intergalactic medium are briefly discussed. A
number of observational challenges are mentioned to inspire future research
directions.


title: The Expansion of G11.2-0.3, a Radio Composite Supernova Remnant

abstract:
  We compare recent observations of the supernova remnant G11.2-0.3 taken with
the VLA during 2001-02 with images from VLA archives (1984-85) to detect and
measure the amount of expansion that has occurred during 17 years. The bright,
circular outer shell shows a mean expansion of (0.71 +/- 0.15)% and (0.50 +/-
0.17)%, from 20- and 6-cm data, respectively, which corresponds to a rate of
0.057' +/- 0.012'/yr at 20 cm and 0.040' +/- 0.013'/yr at 6 cm. From this
result, we estimate the age of the remnant to be roughly between 960 and 3400
years old, according to theoretical models of supernova evolution. This is
highly inconsistent with the 24000 yr characteristic age of PSR J1811-1925,
located at the remnant's center, but, rather, is consistent with the time since
the historical supernova observed in 386 AD. We also predict that G11.2-0.3 is
currently in a pre-Sedov evolutionary state, and set constraints on the
distance to the remnant based on Chandra X-ray spectral results.


title: Type II Quasars from the SDSS

abstract:
  Type II quasars are suggested by unification models of Active Galactic Nuclei
as luminous analogs of Seyfert 2 galaxies. A number of different methods have
been used hitherto to discover type II quasars, but only a handful have been
found. We selected about 150 type II quasar candidates from the SDSS
spectroscopic database; these objects have strong narrow high-ionization
emission lines. We describe the selection procedure and estimate intrinsic
luminosities of these optically obscured AGN. A campaign to perform a
multi-wavelength follow-up of the sample is now underway.


title: Minimizing Strong Telluric Absorption in Near Infra-red Stellar Spectra

abstract:
  We have obtained high resolution spectra (R = 25000) of an A star over
varying airmass to determine the effectiveness of telluric removal in the limit
of high signal to noise. The near infra-red line HeI at 2.058 microns, which is
a sensitive indicator of physical conditions in massive stars, supergiants, HII
regions and YSOs, resides among pressure broadened telluric absorption from
carbon dioxide and water vapor that varies both in time and with observed
airmass.
  Our study shows that in the limit of bright stars at high resolution,
accuracies of 5% are typical for high airmass observations (greater than 1.9),
improving to a photon-limited accuracy of 2% at smaller airmasses (less than
1.15). We find that by using the continuum between telluric absorption lines of
a ro-vibrational fan a photon-limited 1% accuracy is achievable.


title: Deep Searches for High Redshift Molecular Absorption

abstract:
  Millimetre-band scans of the frequency space towards optically dim quasars is
potentially a highly efficient method for detecting new high redshift molecular
absorption systems. Here we describe scans towards 7 quasars over wide
bandwidths (up to 23 GHz) with sensitivity limits sufficient to detect the 4
redshifted absorbers already known. With wider frequency bands, highly
efficient searches of large numbers of possibly obscured objects will yield
many new molecular absorbers.


title:
Black hole masses and Doppler factors of $\gamma$-ray active galactic
  nuclei

abstract:
  The sizes of the broad-line regions (BLRs) in $\gamma$-ray active galactic
nuclei (AGNs) are estimated from their optical continuum luminosity by using
the empirical relation between $R_{\rm BLR}$ and $L_{\lambda,\rm opt}$. Using
the broad emission line data, we derive the photon energy density in the
relativistic blobs near the massive black holes in AGNs. We calculate the power
of the broad-line photons Compton up-scattered by the relativistic electrons in
the blobs. Compared with observed $\gamma$-ray emission data, the Doppler
factors $\delta$ of the blobs for a sample of 36 $\gamma$-ray AGNs are derived,
which are in the range of $\sim 3-17$. We estimate the central black hole
masses of these $\gamma$-ray AGNs from the sizes of the BLR and the broad line
widths. It is found that the black hole masses are in the range of $\sim
10^{8}-10^{10}M_{\odot}$. A significant correlation is found between the
Doppler factor $\delta$ and the core dominance parameter $R$. The results are
consistent with the external radiation Compton (ERC) models for $\gamma$-ray
emission from AGNs. The soft seed photons are probably from the broad-line
regions.


title: Unusual State in V Sagittae

abstract:
  It has been recently demonstrated that the recurring high/low states in the
peculiar binary V Sge can be explained by considering the limit-cycle
oscillation involving negative feedback by the wind on the mass-transfer from
the secondary star. We noticed, from the recent observations reported to the
VSNET (http://www.kusastro.kyoto-u.ac.jp/vsnet/), the presence of a different
state of recurring variations (recurrence time ~30 d) showing a gradual rise
and a sudden drop in brightness. The observed features of this light variation
are unlikely to be reproduced by the limit-cycle oscillation mechanism
involving a mass-transfer variation from the secondary star (Hachisu, Kato
2003, astro-ph/0308065). We suggest that the phenomenon originates from an
unidentified intrinsic instability in the disk or in the wind of a high
luminosity object as in V Sge.


title: Evolution of the Synchrotron Spectrum in Mrk421 during the 1998 Campaign

abstract:
  The uninterrupted 7-day ASCA observations of the TeV blazar Mrk421 in 1998
have clearly revealed that X-ray flares occur repeatedly. In this paper, we
present the results of the time-resolved spectral analysis of the combined data
taken by ASCA, RXTE, BeppoSAX, and EUVE. In this object - and in many other TeV
blazars - the precise measurement of the shape of the X-ray spectrum, which
reflects the high energy portion of the synchrotron component, is crucial in
determining the high energy cutoff of the accelerated electrons in the jet.
Thanks to the simultaneous broadband coverage, we measured the 0.1-25 keV
spectrum resolved on time scales as short as several hours, providing a great
opportunity to investigate the detailed spectral evolution at the flares. By
analyzing the time subdivided observations, we parameterize the evolution of
the synchrotron peak, where the radiation power dominates, by fitting the
combined spectra with a quadratic form (where the vFv flux at the energy E
obeys log vFv(E)=log(vFv_peak) - const x (log E - log Epeak)^2). In this case,
we show that there is an overall trend that the peak energy Ep and peak flux
vFvp both increase or decrease together. The relation of the two parameters is
best described as Ep \propto vFvp^{0.7} for the 1998 campaign. Similar results
were derived for the 1997 observation, while the relation gave a smaller index
when included both 1997 and 1998 data. On the other hand, we show that this
relation, and also the detailed spectral variations, differ from flare to flare
within the 1998 campaign. We suggest that the observed features are consistent
with the idea that flares are due to a appearance of a new spectral component.
With the availability of the simultaneous TeV data, we also show that there
exists a clear correlation between the synchrotron peak flux and the TeV flux.


title: Isocurvature Fluctuations Induce Early Star Formation

abstract:
  The early reionisation of the Universe inferred from the WMAP polarisation
results, if confirmed, poses a problem for the hypothesis that scale-invariant
adiabatic density fluctuations account for large-scale structure and galaxy
formation. One can only generate the required amount of early star formation if
extreme assumptions are made about the efficiency and nature of early
reionisation. We develop an alternative hypothesis that invokes an additional
component of a non-scale-free isocurvature power spectrum together with the
scale-free adiabatic power spectrum for inflation-motivated primordial density
fluctuations. Such a component is constrained by the Lyman alpha forest
observations, can account for the small-scale power required by spectroscopic
gravitational lensing, and yields a source of early star formation that can
reionise the universe at z~20 yet becomes an inefficient source of ionizing
photons by z~10, thereby allowing the conventional adiabatic fluctuation
component to reproduce the late thermal history of the intergalactic medium.


title: Coronal abundances from high-resolution X-ray data: The case of Algol

abstract:
  We discuss the determination of elemental abundances from high resolution
X-ray data. We emphasize the need for an accurate determination of the
underlying temperature structure and advocate the use of a line ratio method
which allows us to utilize, first, the strongest lines observed in the X-ray
spectra, and second, lines that span a rather wide temperature range. We point
out the need to use continuous emission measure distributions and show via
example that modeling in terms of individual temperature components yields
errors of more than 50%. We stress the need to derive differential emission
measure distributions based on physical assumptions and considerations. We
apply our methods to the Chandra LETGS spectrum of Algol and show that nitrogen
is considerably enhanced compared to cosmic abundances by a factor of 2 while
carbon is depleted by at least a factor of 25. Iron, silicon, and magnesium,
are all depleted compared to cosmic abundances, while the noble gas neon has
the relatively highest abundance.


title: Photon mass and cosmological constant bounds from spacetime torsion

abstract:
  Photon mass and Cartan contortion bounds recently obtained from tiny Lorentz
violation observations in cosmology are used to find a limit of ${\lambda}\le
10^{-4}{\alpha}$ for the massive photon-torsion dimensionless coupling. Here
${\alpha}$ represents the fine-structure constant. A gauge invariant Proca
electrodynamics in spacetime endowed with torsion in de Sitter spacetime is
used to obtain an upper bound for the present value of the cosmological
constant given by ${\Lambda}\le 10^{-56} cm^{-2}$. This result is obtained in
regions of the universe where the photons are massless. A relation between the
contortion, photon mass and the radius of the universe is obtained. The Proca
electrodynamics with torsion and the radius of the universe allow us to place
more stringent bounds for the photon mass of $m_{\gamma}{\le} 10^{-44} GeV$
which is only two orders of magnitude lower than the astronomical bounds given
by the PARTICLE DATA GROUP (PDG). We also show that charge is locally conserved
in de Sitter spacetime with torsion and that plane waves are shown to be
damping by contortion inhomogeneities while dispersion is isotropic and
therefore Proca-Cartan photons do not violate Lorentz invariance.


title: Stellar Abundances in Young and Intermediate Age GCs

abstract:
  Globular Cluster (GC) formation seems to be a widespread mode of star
formation in extreme starbursts triggered by strong interactions and mergers of
massive gas-rich galaxies. We use our detailed chemically consistent
evolutionary synthesis models for spiral galaxies to predict stellar abundances
and abundance ratios of those second generation GCs as a function of their age
or formation redshift. Comparison with observed spectra of young star clusters
formed recently in an ongoing intercation (NGC 4038/39) and a merger remnant
(NGC 7252) are encouraging. Abundances and abundance ratios (and their
respective spreads) among young and intermediate cluster populations and among
the red peak GCs of elliptical/S0 galaxies with bimodal GC color distributions
are predicted to bear a large amount of information about those clusters'
formation processes and environment. Not only the bright young clusters but
also representative populations of "old" GCs in E/S0 galaxies are readily
accessible to MOS on 10m class telescopes.


title: From Young to Old: Spectral Models for Star Cluster Systems

abstract:
  Evolutionary synthesis models for star clusters of various metallicities
including gaseous emission during the lifetime of the ionising stars are used
to model star cluster systems comprising two populations: an old metal-poor
globular clusters (GC) population similar to that of the Milky Way halo and a
second GC population of arbitrary metallicity. We investigate the time
evolution of color distributions and luminosity functions for the two GC
populations in comparison with observations on E/S0 galaxies. We show that
multi-passband data for GC populations give clues to the relative ages and
metallicities of blue and red subpopulations and help constrain formation
scenarios for their parent galaxies.


title: Outbursts of Young Stellar Objects

abstract:
  We argue that the outbursts of the FU Orionis stars occur on timescales which
are much longer than expected from the standard disc instability model with
\alpha_{c} \gtrsim 10^{-3}. The outburst, recurrence, and rise times are
consistent with the idea that the accretion disc in these objects is truncated
at a radius R_{i} \sim 40 \rsun. In agreement with a number of previous authors
we suggest that the inner regions of the accretion discs in FU Ori objects are
evacuated by the action of a magnetic propeller anchored on the central star.
We develop an analytic solution for the steady state structure of an accretion
disc in the presence of a central magnetic torque, and present numerical
calculations to follow its time evolution. These calculations confirm that a
recurrence time that is consistent with observations can be obtained by
selecting appropriate values for viscosity and magnetic field strength.


title:
Abundance differences between the neutral and the ionized gas of the
  dwarf galaxy IZw 36

abstract:
  We present a FUSE spectroscopic study of the nearby gas--rich,
metal--deficient blue compact dwarf (BCD) galaxy IZw 36. Atomic hydrogen and
many metal lines are observed in absorption against the stellar continuum of
young, massive stars embedded in the ionized region. Profile fitting of
absorption lines allowed us to determine abundances and investigate the
chemical composition of the neutral gas. This study present strong evidences
that nitrogen is 16 (+7 -8) times less abundant in the neutral gas with respect
to the ionized gas (all uncertainties are 2 sigma. Similarly, the oxygen
abundance estimated using phosphorus as a tracer is lower in the neutral gas by
a factor 8 (+17 -5). We also find that argon is underabundant by a factor 32
(+8 -7) and that log (ArI/OI) < -3.0 which is inconsistent with the solar value
-2.1 (+0.1 -0.1) (Lodders2003), implying that argon is likely ionized into ArII
in the neutral medium.


title: Spatially resolved X-ray emission of EQ Pegasi

abstract:
  We present an analysis of an XMM-Newton observation of the M dwarf binary EQ
Pegasi with a special focus on the the spatial structure of the X-ray emission
and the analysis of light curves. Making use of data obtained with EPIC
(European Photon Imaging Camera) we were for the first time able to spatially
resolve the two components in X-rays and to study the light curves of the
individual components of the EQ Peg system. During the observation a series of
moderate flares was detected, where it was possible to identify the respective
flaring component.


title:
Cross-correlation of the CMB and foregrounds phases derived from the
  WMAP data

abstract:
  We present circular and linear cross-correlation tests and the
"friend-of-friend" analysis for phases of the Internal Linear Combination Map
(ILC) and the WMAP foregrounds for all K--W frequency bands at the range of
multipoles $\ell\le100$. We compare also Tegmark, de Oliveira-Costa and
Hamilton (2003) and Naselsky et al. (2003) cleaned maps with corresponding
foregrounds. We have found significant deviations from the expected Poissonian
statistics for all the cleaned maps and foregrounds. Our analysis shows that,
for a low multipole range of the cleaned maps, power spectra contains some of
the foregrounds residuals mainly from the W band.


title: ESO422-G028: The Host Galaxy of a GRG

abstract:
  ESO422-G028 denotes the very center cD-galaxy of the giant radio source
B0503-286 (Saripalli et al. 1986, Subrahmanya and Hunstead, 1986). The angular
extent of the associated radio structure is about 42.4 arcmin, which
corresponds to a linear size of 1.89 Mpc (with Omega_M=0.27, Omega_Lambda=0.73,
and H_0=71 km/s/Mpc). Here we present new high-frequency total-power and
polarization radio maps obtained with the Effelsberg 100-m dish. In addition,
we correlate the radio data with optical and X-ray observations to investigate
the physical conditions of both, the host galaxy and the extended structure.


title:
Giant Radio Sources in View of the Dynamical Evolution of FRII-type
  Population

abstract:
  The time evolution of giant (D>1 Mpc) lobe-dominated galaxies is analysed on
the basis of dynamical evolution of the entire FRII-type population.


title: INTEGRAL Field Spectroscopy of the Extended Ionized Gas in Arp 220

abstract:
  Integral field optical spectroscopy with the INTEGRAL system has been used to
investigate for the first time the two-dimensional kinematic and ionization
properties of the extended, warm ionized gas in Arp 220 over an area of 28 kpc
by 15 kpc. The structure of the ionized gas is divided into well identified
regions associated with the X-ray emitting plumes and extended lobes. Changes
in the ionization state of the gas along the major axis of the plumes are
detected, in particular in the outer regions of the northwestern plume where
the transition between the main stellar body of the galaxy and a broad, low
surface brightness tidal tail is located. If the plumes are produced by a
starburst-driven galactic wind, the efficiency in the conversion of mechanical
to radiation energy is a factor of at least 10 smaller than in galactic winds
developed in edge-on spirals with well defined rotation and outflowing axis.
The kinematic properties of the lobes are to a first order in agreement with
the predictions of the merger scenario according to which the lobes are
tidal-induced gas condensations produced during the merging process. The
largest velocity gradients and velocity deviations from the systemic velocity
are not associated with the plumes, but with the outer stellar envelope and
broad tidal tails at distances of up to 7.5 kpc, indicating that the large
scale kinematics of the extended ionized gas in Arp 220, is most likely
dominated by the tidal-induced motions, and not by galactic winds associated
with nuclear starbursts.


title: The Giant Pillars of the Carina Nebula

abstract:
  Results are presented from a multi-wavelength study of the giant pillars
within the Carina Nebula. Using near-IR data from 2MASS, mid-IR data from MSX,
843MHz radio continuum maps from the MOST, and molecular line and continuum
observations from the SEST, we investigate the nature of the pillars and search
for evidence of ongoing star formation within them. Photodissociation regions
(PDRs) exist across the whole nebula and trace the giant pillars, as well as
many ridges, filaments, and condensations (Av > 7 mag). Morphological
similarities between emission features at 21um and 843MHz adjacent to the PDRs,
suggests that the molecular material has been carved by the intense stellar
winds and UV radiation from the nearby massive stars. In addition, star forming
cores are found at the tips of several of the pillars. Using a stellar density
distribution, several candidate embedded clusters are also found. One is
clearly seen in the 2MASS images and is located within a dense core
(G287.84-0.82). A search for massive young stellar objects and compact HII
regions using mid-IR colour criteria, reveal twelve candidates across the
complex. Grey-body fits to SEDs for four of these objects are suggestive of
OB-stars. We find that massive star formation in the Carina Nebula is occurring
across the whole complex and confirm it has been continuous over the past 3
Myrs.


title:
Redshift Measurements of Faint Distant Giant Radio Galaxies and
  Observational Constraints on their Jet Power and Dynamical Age

abstract:
  The redshifts of faint radio galaxies identified with giant radio source
candidates selected from the sample of Machalski et al. (2001) have been
measured. Given the redshift, the projected linear size and radio luminosity
are then determined. The above, supplemented with the axial ratio of the
sources (evaluated from the radio maps) allows to constrain their jet power and
the dynamical age using the analytical model of Kaiser et al. (1997) but
modified by allowing the axial ratio of the source's cocoon to evolve in time.


title: Searching for massive clusters in weak lensing surveys

abstract:
  We explore the ability of weak lensing surveys to locate massive clusters. We
use both analytic models of dark matter halos and mock weak lensing surveys
generated from a large cosmological N-body simulation. The analytic models
describe average properties of weak lensing halos and predict the number
counts, enabling us to compute an effective survey selection function. We test
the model prediction for the peak number counts in weak lensing mass maps
against the mock numerical data, and find that the noise due to intrinsic
galaxy ellipticities causes a systematic effect which increases the peak
counts. We develop a correction scheme for the systematic effect in an
empirical manner, and show that, after the correction, the model prediction
agrees well with the mock data. The mock data is also used to examine the
completeness and efficiency of the weak lensing halo search with fully taking
into account the noise and the projection effect by large-scale structures. We
show that the detection threshold of S/N=4-5 gives an optimal balance between
completeness and efficiency. Our results suggest that, for a weak lensing
survey with a galaxy number density of ng=30/arcmin^2 with a mean redshift z=1,
the mean number of peaks in the 10sq deg area is N_peak=62 for a detection
threshold S/N=4. The contamination rate is 42%, and thus, on average, 36 out of
62 peaks (at least) are signals from real halos. Weak lensing surveys thus
provide a reasonably efficient way to searching for massive clusters.


title: Spectral-ageing analysis of selected distant giant radio galaxies

abstract:
  Very deep 4.9 GHz observations with the VLA are used to supplement available
radio maps at the frequencies of 325 MHz (WENSS survey) and 1.4 GHz (NVSS
survey) in order to study the synchrotron spectra and radiative ages of
relativistic particles in the extended lobes of distant giant radio galaxies
selected from the sample of Machalski et al. (2001).


title: Cosmological model with $\Omega_M$-dependent cosmological constant

abstract:
  The idea here is to set the cosmical constant $\lambda$ proportional to the
scalar of the stress-energy tensor of the ordinary matter. We investigate the
evolution of the scale factor in a cosmological model in which the cosmological
constant is proportional to the scalar of the stress-energy tensor.


title: Noether symmetry in the higher order gravity theory

abstract:
  Noether symmetry for higher order gravity theory has been explored, with the
introduction of an auxiliary variable which gives the only correct quantum
desccription of the theory, as shown in a series of earlier papers. The
application of Noether theorem in higher order theory of gravity turned out to
be a powerful tool to find the solution of the field equations. A few such
physically reasonable solutions like power law inflation are presented.


title:
Revisiting the Globular Cluster System of the Merger Remnant Elliptical
  NGC 3610

abstract:
  We have obtained Keck spectra of six candidate globular clusters (GCs) in the
dynamically young elliptical galaxy NGC 3610, supplementing our previous Keck
spectra of eight confirmed GCs (Strader et al. 2003). Five of our new
candidates are confirmed to be GCs. Of the thirteen GCs, eleven are located
within the K band effective radius of 7 kpc. Two of these thirteen clusters are
found to be young (~ 2 Gyr) and very metal-rich ([Z/H] ~ +0.5), three are old
and metal-poor, and the remaining eight clusters are old and metal-rich. The
ages of the young clusters are consistent with a recent spectroscopic age
estimate of 1.6+/-0.5 Gyr for the galaxy itself (Denicolo et al. 2003) and
suggest that these clusters formed in the disk-disk merger which likely created
NGC 3610. Intriguingly, both young GCs have [alpha/Fe] ~ +0.3, while the
majority of the old clusters are not alpha-enhanced, in contrast to Galactic
and M31 GCs, and contrary to predictions of nucleosynthetic calculations. The
two old subpopulations of GCs can be attributed to the merger progenitors. The
relative numbers of old and new metal-rich GCs are poorly constrained because
of the expected differences in radial distributions of the two subpopulations.
However, based on our spectroscopic results and a comparison of the Hubble
Space Telescope color magnitude diagram (Whitmore et al. 2002) with stellar
population models, we argue that more than half of the metal-rich GCs are
likely to be old.


title:
Monitoring Chandra observations of the quasi-persistent neutron-star
  X-ray transient MXB 1659-29 in quiescence: the cooling curve of the heated
  neutron-star crust

abstract:
  We have observed the quasi-persistent neutron-star X-ray transient and
eclipsing binary MXB 1659-29 in quiescence on three occasions with Chandra. The
purpose of our observations was to monitor the quiescent behavior of the source
after its last prolonged (~2.5 years) outburst which ended in September 2001.
The X-ray spectra of the source are consistent with thermal radiation from the
neutron-star surface. We found that the bolometric flux of the source decreased
by a factor of 7-9 over the time-span of 1.5 years between our first and last
Chandra observations. The effective temperature also decreased, by a factor of
1.6-1.7. The decrease in time of the bolometric flux and effective temperature
can be described using exponential decay functions, with e-folding times of 0.7
and ~3 years, respectively. Our results are consistent with the hypothesis that
we observed a cooling neutron-star crust which was heated considerably during
the prolonged accretion event and which is still out of thermal equilibrium
with the neutron-star core. We could only determine upper-limits for any
luminosity contribution due to the thermal state of the neutron-star core. The
rapid cooling of the neutron-star crust implies that it has a large thermal
conductivity. Our results also suggest that enhanced cooling processes are
present in the neutron-star core.


title:
Redshift estimation of clusters by wavelet decomposition of their
  Sunyaev-Zel'dovich morphology

abstract:
  A method for estimating redshifts of galaxy clusters based solely on resolved
Sunyaev-Zel'dovich (SZ) images is proposed. Given a high resolution SZ cluster
image (with FWHM of approx. 1 arcmin), the method indirectly measures its
structure related parameters (amplitude, size, etc.) by fitting a model
function to the higher order wavelet momenents of the cluster's SZ morphology.
The applicability and accuracy of the wavelet method is assessed by applying it
to maps of a set of clusters extracted from hydrodynamical simulations of
cosmic structure formation. The parameters, derived by a fit to the spectrum of
wavelet moments as a function of scale, are found to show a dependence on
redshift z that is of the type x(z) = x_1 exp(-z/x_2) + x_3, where the monotony
of this functional behaviour and the non-degeneracy of those parameters allow
inversion and estimation of the redshift z. The average attainable accuracy in
the z-estimation relative to 1+z is approx. 4-5% out to z = 1.2, which is
comparable to photometric redshifts. For single-frequency SZ interferometers,
where the ambient fluctuating CMB is the main noise source, the accuracy of the
method drops slightly to <Delta z/(1+z)> = 6-7%.


title: Molecular Line Emission from Accretion Disks Around YSOs

abstract:
  In this work we model the expected molecular emission from protoplanetary
disks, modifying different physical parameters, such as dust grain size, mass
accretion rate, viscosity, and disk radius, to obtain observational signatures
in these sources. Having in mind possible future observations, we study
correlations between physical parameters and observational characteristics. Our
aim is to determine the kind of observations that will allow us to extract
information about the physical parameters of disks. We also present prospects
for molecular line observations of protoplanetary disks, using millimeter and
submillimeter interferometers (e.g., SMA or ALMA), based on our results.


title: Simultaneous optical and X-ray high speed photometry of Cyg X-2

abstract:
  The X-ray emission from X-ray binaries may originate in flares occurring when
magnetic loops anchored in the disc reconnect. In analogy with our Sun, H alpha
emission should arise as the accelerated electrons thermalize in the optically
emitting disc, perhaps leading to correlated variability between X-rays, H
alpha and the optical continuum. We present simultaneous X-ray and optical high
speed photometry of the neutron star low-mass X-ray binary Cyg X-2 to search
for such correlations. The highest time resolution achieved is 5 ms in white
light and 100 ms with a 3 nm filter centred on H alpha. We find power on
timescales > 100s (flickering) in optical with a total r.m.s. of a few %, about
an order of magnitude less than that seen in X-rays. We do not find significant
correlations between the X-ray and optical fluxes on short timescales, hence
cannot conclude whether magnetic flares contribute significantly to the optical
emission.