title:
Swift observations of the prompt X-ray emission and afterglow from
  GRB050126 and GRB050219A

abstract:
  We report on the temporal and spectral characteristics of the early X-ray
emission from the Gamma Ray Bursts GRB050126 and GRB050219A as observed by
Swift. The X-ray light-curves of these 2 bursts both show remarkably steep
early decays (F(t)\propto t^{-3}), breaking to flatter slopes on timescales of
a few hundred seconds. For GRB050126 the burst shows no evidence of spectral
evolution in the 20-150 keV band, and the spectral index of the gamma-ray and
X-ray afterglows are significantly different suggesting a separate origin. By
contrast the BAT spectrum of GRB050219A displays significant spectral
evolution, becoming softer at later times, with Gamma evolving toward the XRT
photon index seen in the early X-ray afterglow phase. For both bursts, the
0.2-10 keV spectral index pre- and post-break in the X-ray decay light-curve
are consistent with no spectral evolution. We suggest that the steep early
decline in the X-ray decay light-curve is either the curvature tail of the
prompt emission; X-ray flaring activity; or external forward shock emission
from a jet with high density regions of small angular size (> Gamma^{-1}). The
late slope we associate with the forward external shock.


title: Tidal Capture of Stars by Intermediate-Mass Black Holes

abstract:
  Recent X-ray observations and theoretical modelling have made it plausible
that some ultraluminous X-ray sources (ULX) are powered by intermediate-mass
black holes (IMBHs). N-body simulations have also shown that runaway merging of
stars in dense star clusters is a way to form IMBHs. In the present paper we
have performed N-body simulations of young clusters such as MGG-11 of M82 in
which IMBHs form through runaway merging. We took into account the effect of
tidal heating of stars by the IMBH to study the tidal capture and disruption of
stars by IMBHs. Our results show that the IMBHs have a high chance of capturing
stars through tidal heating within a few core relaxation times and we find that
1/3 of all runs contain a ULX within the age limits of MGG-11, a result
consistent with the fact that a ULX is found in this galaxy. Our results
strengthen the case for some ULX being powered by intermediate-mass black
holes.


title:
A Principal Component Analysis approach to the Star Formation History of
  elliptical galaxies in Compact Groups

abstract:
  (Abridged) Environmental differences in the stellar populations of early-type
galaxies are explored using principal component analysis (PCA), focusing on
differences between elliptical galaxies in Hickson Compact Groups (HCGs) and in
the field. The method is model-independent and relies on variations between the
observed spectra. The projections (PC1,PC2) reveal a difference with respect to
environment, with a wider range in PC1 and PC2 in the group sample. We define a
spectral parameter (zeta=0.36PC1-PC2) which simplifies this result to a single
number: field galaxies have a very similar value of zeta, whereas HCG galaxies
span a wide range in this parameter. We obtain a strong correlation between the
values of zeta and the mass fraction in younger stars, so that some group
galaxies present a higher fraction of them. PCA is more sensitive than other
methods based on a direct analysis of observables such as the structure of the
surface brightness profile or the equivalent width of absorption lines. The
latter do not reveal any significant variation between field and compact group
galaxies. Our results imply that the presence of young stars only amounts to a
fraction of a percent in its contribution to the total variance.


title: Roche Lobe Shapes for testing MOND-like Modified Gravity

abstract:
  Dark Matter (DM) theories and mass-tracing-light theories like MOND are by
construction nearly degenerate on galactic scales, but not when it comes to the
predicted shapes of Roche Lobes of a two-body system (e.g., a globular cluster
orbiting a host galaxy). We show that the flattening of the Roche lobe is
sensitive to the function mu(g) in modification of the law of gravity. We
generalise the analytical results obtained in the deep-MOND limit by Zhao
(2005, astro-ph/0511713 and astro-ph/0512425), and consider a binary in the
framework of a MOND-like gravity modification function mu(g) or a general
non-Keplerian gravity g \propto R^-\zeta. We give analytical expressions for
the inner Lagrange point and Robe lobe axis ratios. The Roche lobe volume is
proven to scale linearly with the true mass ratio, which applies to any mu(g),
hence mass-tracing light models would overpredict the Roche lobe of a DM-poor
globular cluster in a DM-rich host galaxy, and underpredict the size of a
DM-richer dwarf satellite. The lobes are squashed with the flattening ~ 0.4 in
the strong gravity and ~ 0.6 in the weak gravity; a precise measurement of the
flattening could be used to verify the anisotropic dilation effect which is
generic to MOND-like gravity. We generalise these results for extended mass
distribution, and compare predicted Roche radii in different gravity theories
with limiting radii of observed globular clusters and dwarf galaxy satellites.


title: The Outburst of HST-1 in the M87 Jet

abstract:
  The X-ray intensity of knot HST-1, 0.85" from the nucleus of the radio galaxy
M87, has increased by more than a factor of 50 during the last 5 years. The
optical increase is similar and our more limited radio data indicate a
commensurate activity. We give the primary results of our Chandra X-ray
Observatory monitoring program and consider some of the implications of this
extreme variability in a relativistic jet. We find that the data support a
'modest beaming synchrotron' model as indicated in our earlier papers. Based on
this model, the decay of the X-ray lightcurve appears to be dominated by light
travel time across the emitting region of HST-1, rather than synchrotron loss
timescales.


title:
Spiral galaxy rotation curves determined from Carmelian general
  relativity

abstract:
  Equations of motion, in cylindrical co-ordinates, for the observed rotation
of gases within the gravitational potential of spiral galaxies have been
derived from Carmeli's Cosmological General Relativity theory. A Tully-Fisher
type relation results and rotation curves are reproduced without the need for
non-baryonic halo dark matter. Two acceleration regimes are discovered that are
separated by a critical accleration $\approx 4.75 \times 10^{-10}$ $m.s^{-2}$.
For accelerations larger than the critical value the Newtonian force law
applies, but for accelerations less than the critical value the Carmelian
regime applies. In the Newtonian regime the accelerations fall off as $r^{-2}$,
but in the Carmelian regime the accelerations fall off as $r^{-1}$. This is new
physics but is exactly what is suggested by Migrom's phenomenological MOND
theory.


title:
Properties of dust in the high-latitude translucent cloud L1780 I:
  Spatially distinct dust populations and increased dust emissivity from ISO
  observations

abstract:
  We have analyzed the properties of dust in the high galactic latitude
translucent cloud Lynds 1780 using ISOPHOT maps at 100 and 200 micrometers and
raster scans at 60, 80, 100, 120, 150 and 200 micrometers. In far-infrared
(FIR) emission, the cloud has a single core that coincides with the maxima of
visual extinction and 200um optical depth. At the resolution of 3.0 arcmin, the
maximum visual extinction is 4.0 mag. At the cloud core, the minimum
temperature and the maximum 200um optical depth are 14.9+/-0.4 K and
2.0+/-0.2x10^{-3}, respectively, at the resolution of 1.5 arcmin. The cloud
mass is estimated to be 18M_{SUN}. The FIR observations, combined with IRAS
observations, suggest the presence of different, spatially distinct dust grain
populations in the cloud: the FIR core region is the realm of the "classical"
large grains, whereas the very small grains and the PAHs have separate maxima
on the Eastern side of the cold core, towards the "tail" of this
cometary-shaped cloud. The color ratios indicate an overabundance of PAHs and
VSGs in L1780. Our FIR observations combined with the optical extinction data
indicate an increase of the emissivity of the big grain dust component in the
cold core, suggesting grain coagulation or some other change in the properties
of the large grains. Based on our observations, we also address the question,
to what extent the 80um emission and even the 100um and the 120um emission
contain a contribution from the small-grain component.


title:
B-type supergiants in the SMC: Rotational velocities and implications
  for evolutionary models

abstract:
  High-resolution spectra for 24 SMC and Galactic B-type supergiants have been
analysed to estimate the contributions of both macroturbulence and rotation to
the broadening of their metal lines. Two different methodologies are
considered, viz. goodness-of-fit comparisons between observed and theoretical
line profiles and identifying zeros in the Fourier transforms of the observed
profiles. The advantages and limitations of the two methods are briefly
discussed with the latter techniques being adopted for estimated projected
rotational velocities (\vsini) but the former being used to estimate
macroturbulent velocities. Only one SMC supergiant, SK 191, shows a significant
degree of rotational broadening (\vsini $\simeq$ 90 \kms). For the remaining
targets, the distribution of projected rotational velocities are similar in
both our Galactic and SMC samples with larger values being found at earlier
spectral types. There is marginal evidence for the projected rotational
velocities in the SMC being higher than those in the Galactic targets but any
differences are only of the order of 5-10 \kms, whilst evolutionary models
predict differences in this effective temperature range of typically 20 to 70
\kms. The combined sample is consistent with a linear variation of projected
rotational velocity with effective temperature, which would imply rotational
velocities for supergiants of 70 \kms at an effective temperature of 28 000 K
(approximately B0 spectral type) decreasing to 32 \kms at 12 000 K (B8 spectral
type). For all targets, the macroturbulent broadening would appear to be
consistent with a Gaussian distribution (although other distributions cannot be
discounted) with an $\frac{1}{e}$ half-width varying from approximately 20 \kms
at B8 to 60 \kms at B0 spectral types.


title: The importance of tides for the Local Group dwarf spheroidals

abstract:
  There are two main tidal effects which can act on the Local Group dwarf
spheroidals (dSphs): tidal stripping and tidal shocking. Using N-body
simulations, we show that tidal stripping always leads to flat or rising
projected velocity dispersions beyond a critical radius; it is $\sim 5$ times
more likely, when averaging over all possible projection angles, that the
cylindrically averaged projected dispersion will rise, rather than be flat. In
contrast, the Local Group dSphs, as a class, show flat or falling projected
velocity dispersions interior to $\sim 1$ kpc. This argues for tidal stripping
being unimportant interior to $\sim 1$ kpc for most of the Local Group dSphs
observed so far.
  These results have important implications for the formation of the dSphs and
for cosmology. A tidal origin for the formation of these Local Group dSphs (in
which they contain no dark matter) is strongly disfavoured. In the cosmological
context, a naive solution to the missing satellites problem is to allow only
the most massive substructure dark matter halos around the Milky Way to form
stars. It is possible for dSphs to reside within these halos ($\sim
10^{10}$M$_\odot$) and have their velocity dispersions lowered through the
action of tidal shocks, but only if they have a central density core in their
dark matter, rather than a cusp. dSphs can reside within cuspy dark matter
halos if their halos are less massive ($\sim 10^{9}$M$_\odot$) and therefore
have smaller central velocity dispersions initially (abridged).


title:
Magnetic Braking of Ap/Bp Stars: Application to Compact Black-Hole X-Ray
  Binaries

abstract:
  We examine the proposal that the subset of neutron-star and black-hole X-ray
binaries that form with Ap or Bp star companions will experience systemic
angular-momentum losses due to magnetic braking, not otherwise operative with
intermediate-mass companion stars. We suggest that for donor stars possessing
the anomalously high magnetic fields associated with Ap and Bp stars, a
magnetically coupled, irradiation-driven stellar wind can lead to substantial
systemic loss of angular-momentum. In this paper we apply this mechanism to a
specific astrophysics problem involving the formation of compact black-hole
binaries with low-mass donor stars. At present, it is not understood how these
systems form, given that low-mass companion stars are not likely to provide
sufficient gravitational potential to unbind the envelope of the massive
progenitor of the black hole during a prior `common-envelope' phase. However,
in the absence of magnetic braking, such systems tend to evolve to long orbital
periods. We show that, with the proposed magnetic braking properties afforded
by Ap and Bp companions, such a scenario can lead to the formation of compact
black-hole binaries with orbital periods, donor masses, lifetimes, and
production rates that are in accord with the observations. In spite of these
successes, our models reveal a significant discrepancy between the calculated
effective temperatures and the observed spectral types of the donor stars.
Finally, we show that this temperature discrepancy would still exist for other
scenarios invoking initially intermediate-mass donor stars, and this presents a
substantial unresolved mystery.


title:
Space-VLBI Polarimetry of the BL Lac Object S5 0716+714: Rapid
  Polarization Variability in the VLBI core

abstract:
  To determine the location of the intra-day variable (IDV) emission region
within the jet of the BL Lac object S5 0716+714, a multi-epoch VSOP
polarization experiment was performed in Autumn 2000. To detect, image, and
monitor the short term variability of the source, three space-VLBI experiments
were performed with VSOP at 5 GHz, separated in time by six days and by one
day. Quasi-contemporaneous flux density measurements with the Effelsberg 100 m
radio telescope during the VSOP observations revealed variability of about 5%
in total intensity and up to 40% in linear polarization in less than one day.
Analysis of the VLBI data shows that the variations are located inside the VLBI
core component of 0716+714. In good agreement with the single-dish
measurements, the VLBI ground array images and the VSOP images, both show a
decrease in the total flux density of ~20 mJy and a drop of ~5 mJy in the
linear polarization of the VLBI core. During the observing interval, the
polarization angle rotated by about 15 degrees. No variability was found in the
jet. The high angular-resolution VSOP images are not able to resolve the
variable component and set an upper limit of <0.1 mas to the size of the core
component. From the variability timescales we estimate a source size of a few
micro-arcseconds and brightness temperatures exceeding 10^15 K. We discuss the
results in the framework of source-extrinsic (interstellar scintillation
induced) and source-intrinsic IDV models.


title:
XMM-Newton observations of the microquasars GRO J1655-40 and GRS
  1915+105

abstract:
  We present results of a sequence of XMM-Newton observations of the two
microquasars GRO J1655-40 and GRS 1915+105. The observations were preformed
using the EPIC-pn camera in the Burst mode. The observations of GRO J1655-40 in
a bright state have made possible a substantial improvement in the calibration
of the Burst mode, with determination of the rate dependence of the Charge
Transfer Efficiency (CTE). We detect He-like Fe K-shell absorption features in
the EPIC-pn spectrum of GRO J1655-40, indicating the presence of a highly
ionized absorber, and clear absorption features at 0.71 and 0.72 keV in the RGS
spectrum, most probably identified as blueshifted Fe XVIII.


title: Do Type-Ia Supernovae Constrain the Total Equation of State?

abstract:
  In this paper, we consider a couple of alternative dark energy models using
the total equation of state of the cosmological fluid, $\wt$. These models are
fit to the recent type-Ia supernovae data and are compared to previously
considered models. The first model is based on the hyperbolic tangent and
provides a good estimate of the rate of the transition to dark energy
domination. The second model is a cubic spline model. This model demonstrates
and quantifies the non-monotonicity in the total equation of state coming from
the supernovae observations. At present, the supernovae observations indicate
significance to non-monotonically decreasing dark energy. We derive constraints
on the spline paramters and compare and constrast the results to the
Cosmological Constant dark energy model. Both the hyperbolic and splines models
indicate that a precise physical notion of dark enegy is a potentially ever
more mysterious quantity?


title: Are monopoles hiding in monopolium?

abstract:
  Dirac showed that the existence of one magnetic pole in the universe could
offer an explanation of the discrete nature of the electric charge. Magnetic
poles appear naturally in most Grand Unified Theories. Their discovery would be
of greatest importance for particle physics and cosmology. The intense
experimental search carried thus far has not met with success. I propose a
Universe with magnetic poles which are not observed free because they hide in
deeply bound monopole--anti-monopole states named monopolium. I study the
feasibility of this proposal and establish signatures for confirming my
scenario.


title: Most precise single redshift bound to Delta alpha/alpha

abstract:
  Verification of theoretical predictions of an oscillating behavior of the
fine-structure constant alpha with cosmic time requires high precision Delta
alpha/alpha measurements at individual redshifts, while in earlier studies the
mean Delta alpha/alpha values averaged over wide redshift intervals were
usually reported. This requirement can be met via the single ion differential
alpha measurement (SIDAM) procedure proposed in Levshakov et al. (2005). We
apply the SIDAM to the FeII lines associated with the damped Ly-alpha system
observed at z=1.15 in the spectrum of HE0515-4414. The weighted mean <Delta
alpha/alpha> calculated on base of carefully selected 34 FeII pairs {1608,X} (X
= 2344, 2374, and 2586 A) is <Delta alpha/alpha> = (-0.07+/-0.84) 10^{-6}
(1sigma C.L.). The precision of this estimate improves by a factor 2 the
previous one reported for the same system by Quast et al. (2004). The obtained
result represents an absolute improvement with respect to what has been done in
the measurements of Delta alpha/alpha.


title: Massive Star Formation: A Tale of Two Theories

abstract:
  The physical mechanism that allows massive stars to form is a major unsolved
problem in astrophysics. Stars with masses $\gtsim 20$ $\msun$ reach the main
sequence while still embedded in their natal clouds, and the immense radiation
output they generate once fusion begins can exert a force stronger than gravity
on the dust and gas around them. They also produce huge Lyman continuum
luminosities, which can ionize and potentially unbind their parent clouds. This
makes massive star formation a more daunting problem than the formation of low
mass stars. In this review I present the current state of the field, and
discuss the two primary approaches to massive star formation. One holds that
the most massive stars form by direct collisions between lower mass stars and
their disks. The other approach is to see if the radiation barrier can be
overcome by improved treatment of the radiation-hydrodynamic accretion process.
I discuss the theoretical background to each model, the observational
predictions that can be used to test them, and the substantial parts of the
problem that neither theory has fully addressed.


title: The Discovery of Tidal Tails Around NGC 5466

abstract:
  We report the discovery of tidal tails around the high-latitude Galactic
globular cluster NGC 5466 in Sloan Digital Sky Survey (SDSS) data. Neural
networks are used to reconstruct the probability distribution of cluster stars
in u,g,r,i and z space. The tails are clearly visible, once extra-galactic
contaminants and field stars have been eliminated. They extend roughly 4
degrees on the sky, corresponding to about 1 kpc in projected length. The
orientation of the tails is in good agreement with the cluster's Galactic
orbit, as judged from the proper motion data.


title:
An analytic investigation of the scatter in the integrated X-ray
  properties of galaxy groups and clusters

abstract:
  (Abridged) We revisit the scaling relationships between the dark matter mass
and observed X-ray luminosity and temperature of galaxy clusters and groups in
the local Universe. Specifically, we compare recent observations with analytic
models of the intracluster medium in which the gas entropy distribution has
been shifted by a variable amount, K0, to investigate the origin of the scatter
in these scaling relations, and its influence on the luminosity and temperature
functions. We find that variations in halo concentration or formation epoch
(which might determine the time available for low entropy gas to cool out) are
insufficient to explain the amount of scatter in the mass-luminosity relation.
Instead, a range of entropy floors at a fixed halo mass, spanning approximately
50 keV sq.cm to 700 keV sq.cm, is required to match the data. This range is
likely related to the variance in heating and/or cooling efficiency from halo
to halo. We demonstrate that these models are consistent with the observed
temperature and luminosity functions of clusters, if scatter in the
mass-luminosity relation is accounted for. Finally, we present predictions for
the redshift evolution of these scaling relations and luminosity/temperature
functions. Comparison with recent data at z<0.7 shows reasonable agreement with
a model that assumes a median entropy floor of K0=200 keV sq.cm. When
observations are extended to group scales (kT < 1 keV), this evolution will
have the potential to discriminate between an entropy floor that is independent
of redshift (for example, in a preheating scenario) and one that depends on the
cooling time of the halo.


title: Relativistic MHD Simulations of Jets with Toroidal Magnetic Fields

abstract:
  This paper presents an application of the recent relativistic HLLC
approximate Riemann solver by Mignone & Bodo to magnetized flows with vanishing
normal component of the magnetic field.
  The numerical scheme is validated in two dimensions by investigating the
propagation of axisymmetric jets with toroidal magnetic fields.
  The selected jet models show that the HLLC solver yields sharper resolution
of contact and shear waves and better convergence properties over the
traditional HLL approach.


title:
Globular cluster systems in low-luminosity early-type galaxies near the
  Fornax Cluster centre

abstract:
  We present a photometric study of the globular cluster systems of the Fornax
cluster galaxies NGC 1374, NGC 1379, and NGC 1387. The data consists of images
from the wide-field MOSAIC Imager of the CTIO 4-m telescope, obtained with
Washington C and Kron-Cousins R filters. The images cover a field of 36 x 36
arcmin, corresponding to 200 x 200 kpc at the Fornax distance. Two of the
galaxies, NGC 1374 and NGC 1379, are low-luminosity ellipticals while NGC 1387
is a low-luminosity lenticular. Their cluster systems are still embedded in the
cluster system of NGC 1399. Therefore the use of a large field is crucial and
some differences to previous work can be explained by this. The colour
distributions of all globular cluster systems are bimodal. NGC 1387 presents a
particularly distinct separation between red and blue clusters and an
overproportionally large population of red clusters. The radial distribution is
different for blue and red clusters, red clusters being more concentrated
towards the respective galaxies. The different colour and radial distributions
point to the existence of two globular cluster subpopulations in these
galaxies. Specific frequencies are in the range S_N= 1.4-2.4, smaller than the
typical values for elliptical galaxies. These galaxies might have suffered
tidal stripping of blue globular clusters by NGC 1399.


title:
Study of core collapse neutrino signals and constraints on neutrino
  masses from a future Galactic Supernova

abstract:
  We study the sensitivity to neutrino masses of a Galactic supernova neutrino
signal as could be measured with the detectors presently in operation and with
future large volume water \v{C}erencov and scintillator detectors. The analysis
uses the full statistics of neutrino events. The method proposed uses the
principles of Bayesian inference reasoning and has shown a remarkably
independence of astrophysical assumptions. We show that, after accounting for
the uncertainties in the detailed astrophysical description of the neutrino
signal and taking into account the effects of neutrino oscillations in the
supernova mantle, detectors presently in operation can have enough sensitivity
to reveal a neutrino mass (or to set upper limits) at the level of 1 eV. This
is sensibly better than present results from tritium $\beta$-decay experiments,
competitive with the most conservative limits from neutrinoless double
$\beta$-decay and less precise but remarkably less dependent from prior
assumptions than cosmological measurements. Future megaton water \v{C}erencov
detectors and large volume scintillator detectors will allow for about a factor
of two improvement in the sensitivity; however, they will not be competitive
with the next generation of tritium $\beta$-decay and neutrinoless double
$\beta$-decay experiments. Using the codes developed to perform the generation
of synthetic supernova signals and their analysis we created a computer
package, SUNG (SUpernova Neutrino Generation tool,
http://urania.udea.edu.co/sungweb), aimed to offer a general purpose solution
to perform calculations in supernova neutrino studies.


title: The halo-model description of marked statistics

abstract:
  Marked statistics allow sensitive tests of how galaxy properties correlate
with environment, as well as of how correlations between galaxy properties are
affected by environment. A halo-model description of marked correlations is
developed, which incorporates the effects which arise from the facts that
typical galaxy marks (e.g., luminosity, color, star formation rate, stellar
mass) depend on the mass of the parent halo, and that massive haloes extend to
larger radii and populate denser regions. Comparison with measured marked
statistics in semi-analytic galaxy formation models shows good agreement on
scales smaller than a Megaparsec, and excellent agreement on larger scales. The
halo-model description shows clearly that the behaviour of some low-order
marked statistics on these scales encodes information about the mean galaxy
mark as a function of halo mass, but is insensitive to mark-gradients within
haloes. Higher-order statistics encode information about higher order moments
of the distribution of marks within haloes. This information is obtained
without ever having to identify haloes or clusters in the galaxy distribution.
On scales smaller than a Megaparsec, the halo-model calculation shows that
marked statistics allow sensitive tests of whether or not central galaxies in
haloes are a special population. A prescription for including more general
mark-gradients in the halo-model description is also provided. The formalism
developed here is particularly well-suited to interpretation of marked
statistics in astrophysical datasets, because it is phrased in the same
language that is currently used to interpret more standard measures of galaxy
clustering.


title: Marked correlations in galaxy formation models

abstract:
  The two-point correlation function has been the standard statistic for
quantifying how galaxies are clustered. The statistic uses the positions of
galaxies, but not their properties. Clustering as a function of galaxy
property, be it type, luminosity, color, etc., is usually studied by analysing
a subset of the full population, the galaxies in the subset chosen because they
have a similar range of properties. We explore an alternative
technique---marked correlations---in which one weights galaxies by some
property or `mark' when measuring clustering statistics. Marked correlations
are particularly well-suited to quantifying how the properties of galaxies
correlate with their environment. Therefore, measurements of marked statistics,
with luminosity, stellar mass, color, star-formation rate, etc. as the mark,
permit sensitive tests of galaxy formation models. We make measurements of such
marked statistics in semi-analytic galaxy formation models to illustrate their
utility. These measurements show that close pairs of galaxies are expected to
be red, to have larger stellar masses, and to have smaller star formation
rates. We also show that the simplest unbiased estimator of the particular
marked statistic we use extensively is very simple to measure---it does not
require construction of a random catalog---and provide an estimate of its
variance. Large wide-field surveys of the sky are revolutionizing our view of
galaxies and how they evolve. Our results indicate that application of marked
statistics to this high quantity of high-quality data will provide a wealth of
information about galaxy formation.


title: Dimensionless constants, cosmology and other dark matters

abstract:
  We identify 31 dimensionless physical constants required by particle physics
and cosmology, and emphasize that both microphysical constraints and selection
effects might help elucidate their origin. Axion cosmology provides an
instructive example, in which these two kinds of arguments must both be taken
into account, and work well together. If a Peccei-Quinn phase transition
occurred before or during inflation, then the axion dark matter density will
vary from place to place with a probability distribution. By calculating the
net dark matter halo formation rate as a function of all four relevant
cosmological parameters and assessing other constraints, we find that this
probability distribution, computed at stable solar systems, is arguably peaked
near the observed dark matter density. If cosmologically relevant WIMP dark
matter is discovered, then one naturally expects comparable densities of WIMPs
and axions, making it important to follow up with precision measurements to
determine whether WIMPs account for all of the dark matter or merely part of
it.


title: Modelling Galaxies with a 3d Multi-Phase ISM

abstract:
  We present a new particle code for modelling the evolution of galaxies. The
code is based on a multi-phase description for the interstellar medium (ISM).
We included star formation (SF), stellar feedback by massive stars and
planetary nebulae, phase transitions and interactions between gas clouds and
ambient diffuse gas, namely condensation, evaporation, drag and energy
dissipation. The latter is realised by radiative cooling and inelastic
cloud-cloud collisions. We present new schemes for SF and stellar feedback.
They include a consistent calculation of the star formation efficiency (SFE)
based on ISM properties as well as a detailed redistribution of the feedback
energy into the different ISM phases. As a first test example we show a model
of the evolution of a present day Milky-Way-type galaxy. Though the model
exhibits a quasi-stationary behaviour in global properties like mass fractions
or surface densities, the evolution of the ISM is locally strongly variable
depending on the local SF and stellar feedback. We start only with two distinct
phases, but a three-phase ISM is formed soon consisting of cold molecular
clouds, a warm gas disk and a hot gaseous halo. Hot gas is also found in
bubbles in the disk accompanied by type II supernovae explosions. The star
formation rate (SFR) is ~1.6 M_sun/year on average decreasing slowly with time
due to gas consumption. In order to maintain a constant SFR gas replenishment,
e.g. by infall, of the order 1 M_sun/year is required. Our model is in fair
agreement with Kennicutt's (1998) SF law including the cut-off at ~10
M_sun/pc^2. Models with a constant SFE, i.e. no feedback on the SF, fail to
reproduce Kennicutt's law.


title: Cluster Ellipticities as a Cosmological Probe

abstract:
  We investigate the dependence of ellipticities of clusters of galaxies on
cosmological parameters using large-scale cosmological simulations. We
determine cluster ellipticities out to redshift unity for LCDM models with
different mean densities $\Omega_m$ and amplitudes of mass fluctuation
$\sigma_{8,0}$. The mean ellipticity increases monotonically with redshift for
all models. Larger values of $\sigma_{8,0}$, i.e., earlier cluster formation
time, produce lower ellipticities. The dependence of ellipticity on $\Omega_m$
is relatively weak in the range $0.2 \leq \Omega_m \leq 0.5$ for high mass
clusters. The mean ellipticity $\bar{e}(z)$ decreases linearly with the
amplitude of fluctuations at the cluster redshift $z$, nearly independent of
$\Omega_m$; on average, older clusters are more relaxed and are thus less
elliptical. The distribution of ellipticities about the mean is approximated by
a Gaussian, allowing a simple characterization of the evolution of ellipticity
with redshift as a function of cosmological parameters. At $z=0$, the mean
ellipticity of high mass clusters is approximated by $\bar{e}(z=0) =
0.248-0.069 \sigma_{8,0} + 0.013 \Omega_{m,0}$. This relation opens up the
possibility that, when compared with future observations of large cluster
samples, the mean cluster ellipticity and its evolution could be used as a new,
independent tool to constrain cosmological parameters, especially the amplitude
of mass fluctuations, $\sigma_{8,0}$.


title: A Galactic Origin for the Local Ionized X-ray Absorbers

abstract:
  Recent Chandra and XMM observations of distant quasars have shown strong
local (z~0) X-ray absorption lines from highly ionized gas, primarily He-like
oxygen. The nature of these X-ray absorbers, i.e., whether they are part of the
hot gas associated with the Milky Way or part of the intragroup medium in the
Local Group, remains a puzzle due to the uncertainties in the distance. We
present in this paper a survey of 20 AGNs with Chandra and XMM archival data.
About 40% of the targets show local OVII He-alpha absorption with column
densities around 10^16 cm^-2; in particular, OVII absorption is present in all
the high quality spectra. We estimate that the sky covering fraction of this
OVII-absorbing gas is at least 63%, at 90% confidence, and likely to be unity
given enough high-quality spectra. Based on (1) the expected number of
absorbers along sight lines toward distant AGNs, (2) joint analysis with X-ray
emission measurements, and (3) mass estimation, we argue that the observed
X-ray absorbers are part of the hot gas associated with our Galaxy. Future
observations will significantly improve our understanding of the covering
fraction and provide robust test of this result.


title:
BOAO Photometric Survey of Galactic Open Clusters. III. Czernik 24 and
  Czernik 27

abstract:
  We present BV CCD photometry for the open clusters Czernik 24 and Czernik 27.
These clusters have never been studied before, and we provide, for the first
time, the cluster parameters; reddening, distance, metallicity and age. Czernik
24 is an old open cluster with age 1.8 +/- 0.2 Gyr, metallicity [Fe/H]=-0.41
+/- 0.15 dex, distance modulus (m-M)_0 = 13.1 +/- 0.3 mag (d=4.1 +/- 0.5 kpc),
and reddening E(B-V) = 0.54 +/- 0.12 mag. The parameters for Czernik 27 are
estimated to be age = 0.63 +/- 0.07 Gyr, [Fe/H]= -0.02 +/- 0.10 dex, (m-M)_0 =
13.8 +/- 0.2 mag (d=5.8 +/- 0.5 kpc), and E(B-V) = 0.15 +/- 0.05 mag. The
metallicity and distance values for Czernik 24 are consistent with the relation
between the metallicity and the Galactocentric distance of other old open
clusters. We find the metallicity gradient of 51 old open clusters including
Czernik 24 to be Delta [Fe/H]/Delta R_gc= -0.064 +/- 0.009 dex/kpc.


title:
The Solar Heavy Element Abundances: I. Constraints from Stellar
  Interiors

abstract:
  The latest solar atmosphere models include non-LTE corrections and 3D
hydrodynamic convection simulations. These models predict a significant
reduction in the solar metal abundance, which leads to a serious conflict
between helioseismic data and the predictions of solar interiors models. We
demonstrate that the helioseismic constraints on the surface convection zone
depth and helium abundance combined with stellar interiors models can be used
to define the goodness of fit for a given chemical composition. After a
detailed examination of the errors in the theoretical models we conclude that
models constructed with the older solar abundances are consistent (<2 \sigma)
with the seismic data. Models constructed with the proposed new low abundance
scale are strongly disfavored, disagreeing at the 15 \sigma level. We then use
the sensitivity of the seismic properties to abundance changes to invert the
problem and infer a seismic solar heavy element abundance mix with two
components: meteoritic abundances, and the light metals CNONe. Seismic
degeneracies between the best solutions for the elements arise for changes in
the relative CNONe abundances and their effects are quantified. We obtain
Fe/H=7.50+/-0.045+/-0.003(CNNe) and O/H=8.86+/-0.041+/-0.025(CNNe) for the
relative CNNe in the GS98 mixture. The inferred solar oxygen abundance disagree
with the abundance inferred from the 3D hydro models. Changes in the Ne
abundance can mimic changes in O for the purposes of scalar constraints.Models
constructed with low oxygen and high neon are inconsistent with the solar sound
speed profile. The implications for the solar abundance scale are discussed.


title: A Quantitative Occam's Razor

abstract:
  This paper derives an objective Bayesian "prior" based on considerations of
entropy/information. By this means, it produces a quantitative measure of
goodness of fit (the "H-statistic") that balances higher likelihood against the
number of fitting parameters employed. The method is intended for
phenomenological applications where the underlying theory is uncertain or
unknown.
  For example, it can help decide whether the large angle anomalies in the CMB
data should be taken seriously.
  I am therefore posting it now, even though it was published before the arxiv
existed.


title: Unravelling the nature of HD 81032 - a new RS CVn Binary

abstract:
  BVR photometric and quasi-simultaneous optical spectroscopic observations of
the star HD 81032 have been carried out during the years 2000 - 2004. A
photometric period of $18.802 \pm 0.07$ d has been detected for this star. A
large group of spots with a migration period of $7.43 \pm 0.07$ years is
inferred from the first three years of the data. H$\alpha$ and Ca II H and K
emissions from the star indicate high chromospheric activity. The available
photometry in the BVRIJHK bands is consistent with spectral type of K0 IV
previously found for this star. We have also examined the spectral energy
distribution of HD 81032 for the presence of an infrared colour excess using
the 2MASS JHK and IRAS photometry, but found no significant excess in any band
abovethe normal values expected for a star with this spectral type. We have
also analyzed the X-ray emission properties of this star using data obtained by
the ROSAT X-ray observatory during its All-Sky Survey phase. An X-ray flare of
about 12 hours duration was detected during the two days of X-ray coverage
obtained for this star. Its X-ray spectrum, while only containing 345 counts,
is inconsistent with a single-temperature component solar-abundance coronal
plasma model, but implies either the presence of two or more plasma components,
non-solar abundances, or a combination of both of these properties. All of the
above properties of HD 81032 suggest that it is a newly identified, evolved RS
CVn binary.


title: Evolution of Galactic Nuclei. I. orbital evolution of IMBH

abstract:
  Resent observations and theoretical interpretations suggest that IMBHs
(intermediate-mass black hole) are formed in the centers of young and compact
star clusters born close to the center of their parent galaxy. Such a star
cluster would sink toward the center of the galaxy, and at the same time stars
are stripped out of the cluster by the tidal field of the parent galaxy. We
investigated the orbital evolution of the IMBH, after its parent cluster is
completely disrupted by the tidal field of the parent galaxy, by means of
large-scale N-body simulations. We constructed a model of the central region of
our galaxy, with an SMBH (supermassive black hole) and Bahcall-Wolf stellar
cusp, and placed an IMBH in a circular orbit of radius 0.086pc. The IMBH sinks
toward the SMBH through dynamical friction, but dynamical friction becomes
ineffective when the IMBH reached the radius inside which the initial stellar
mass is comparable to the IMBH mass. This is because the IMBH kicks out the
stars. This behavior is essentially the same as the loss-cone depletion
observed in simulations of massive SMBH binaries. After the evolution through
dynamical friction stalled, the eccentricity of the orbit of the IMBH goes up,
resulting in the strong reduction in the merging timescale through
gravitational wave radiation. Our result indicates that the IMBHs formed close
to the galactic center can merge with the central SMBH in short time. The
number of merging events detectable with DECIGO is estimated to be around 50
per year. Event rate for LISA would be similar or less, depending on the growth
mode of IMBHs.


title: X-Ray and Infrared Enhancement of Anomalous X-ray Pulsar 1E 2259+58

abstract:
  The long term (~1.5 years) X-ray enhancement and the accompanying infrared
enhancement light curves of the anomalous X-ray pulsar 1E 2259+58 following the
major bursting epoch can be accounted for by the relaxation of a fall back disk
that has been pushed back by a gamma-ray flare. The required burst energy
estimated from the results of our model fits is low enough for such a burst to
have remained below the detection limits. We find that an irradiated disk model
with a low irradiation efficiency is in good agreement with both X-ray and
infrared data. Non-irradiated disk models also give a good fit to the X-ray
light curve, but are not consistent with the infrared data for the first week
of the enhancement.


title: BeppoSAX view of radio-loud Active Galactic Nuclei

abstract:
  A systematic analysis of a large sample of radio-loud Active Galactic Nuclei
available in the BeppoSAX public archive has been performed. The sample
includes 3 Narrow Line Radio Galaxies (NLRG), 10 Broad Line Radio Galaxies
(BLRG), 6 Steep Spectrum Radio Quasars (SSRQ), and 16 Flat Spectrum Radio
Quasars (FSRQ). According to the unified models, these classes correspond to
objects with increasing viewing angles. As expected, the presence of a
non-thermal beamed component emerges clearly in FSRQ. This class shows in fact
a featureless continuum (with the exception of 3C273), and a significantly
flatter average spectral slope. On the contrary, traces of a non-thermal
Doppler enhanced radiation are elusive in the other classes. We find that the
iron line equivalent widths (EW) are generally weaker in radio- loud AGN than
in Seyfert 1 galaxies, and confirm the presence of an X-ray Baldwin effect,
i.e. a decrease of EW with the 2--10 keV luminosity (L) from Seyferts to BLRG
and quasars. Since the EW--L anti-correlation is present also in radio-quiet
AGN alone, this effect cannot be ascribed entirely to a strongly beamed jet
component. Possible alternative interpretations are explored.


title:
Coincident GRB neutrino flux predictions: Implications for experimental
  UHE neutrino physics

abstract:
  In the hadronic fireball phenomenology of Gamma Ray Bursts (GRBs), it is
expected that the observed photons are accompanied by UHE neutrinos, which have
not been observed yet. It is one of the challenges of experimental UHE neutrino
astrophysics to look for a signal from GRBs. In this paper, the differences
between a search for a diffuse signal and an examination of a source sample
given by e.g. BATSE will be analyzed. Since redshift information is needed to
determine the correct energy spectrum, long duration bursts with redshifts from
different estimate methods will be used. We will start with an overview of the
current understanding of GRB neutrino physics and will then use this knowledge
to make predictions for a coincidence flux and a corresponding diffuse flux. It
can be shown that shape and normalization of the spectrum is highly dependent
on the set of bursts used and that individual bursts can determine the total
spectrum.


title:
Hot Organic Molecules Toward a Young Low-Mass Star: A Look at Inner Disk
  Chemistry

abstract:
  Spitzer Space Telescope spectra of the low mass young stellar object (YSO)
IRS 46 (L_bol ~ 0.6 L_sun) in Ophiuchus reveal strong vibration-rotation
absorption bands of gaseous C2H2, HCN, and CO2. This is the only source out of
a sample of ~100 YSO's that shows these features and the first time they are
seen in the spectrum of a solar-mass YSO. Analysis of the Spitzer data combined
with Keck L- and M-band spectra gives excitation temperatures of > 350 K and
abundances of 10(-6)-10(-5) with respect to H2, orders of magnitude higher than
those found in cold clouds. In spite of this high abundance, the HCN J=4-3 line
is barely detected with the James Clerk Maxwell Telescope, indicating a source
diameter less than 13 AU. The (sub)millimeter continuum emission and the
absence of scattered light in near-infrared images limits the mass and
temperature of any remnant collapse envelope to less than 0.01 M_sun and 100 K,
respectively. This excludes a hot-core type region as found in high-mass YSO's.
The most plausible origin of this hot gas rich in organic molecules is in the
inner (<6 AU radius) region of the disk around IRS 46, either the disk itself
or a disk wind. A nearly edge-on 2-D disk model fits the spectral energy
distribution (SED) and gives a column of dense warm gas along the line of sight
that is consistent with the absorption data. These data illustrate the unique
potential of high-resolution infrared spectroscopy to probe organic chemistry,
gas temperatures and kinematics in the planet-forming zones close to a young
star.


title: Magnetars: Structure and evolution from p-star models

abstract:
  P-stars are compact stars made of up and down quarks in $\beta$-equilibrium
with electrons in a chromomagnetic condensate. We discuss p-stars endowed with
super strong dipolar magnetic field which, following consolidated tradition in
literature, are referred to as magnetars. We show that soft gamma-ray repeaters
and anomalous $X$-ray pulsars can be understood within our theory. We find a
well defined criterion to distinguish rotation powered pulsars from magnetic
powered pulsars. We show that glitches, that in our magnetars are triggered by
magnetic dissipative effects in the inner core, explain both the quiescent
emission and bursts in soft gamma-ray repeaters and anomalous $X$-ray pulsars.
We account for the braking glitch from SGR 1900+14 and the normal glitch from
AXP 1E 2259+586 following a giant burst. We discuss and explain the observed
anti correlation between hardness ratio and intensity. Within our magnetar
theory we are able to account quantitatively for light curves for both
gamma-ray repeaters and anomalous $X$-ray pulsars. In particular we explain the
puzzling light curve after the June 18, 2002 giant burst from AXP 1E 2259+586.


title: Globular cluster system and Milky Way properties revisited

abstract:
  Updated data of the 153 Galactic globular clusters are used to readdress
fundamental parameters of the Milky Way. We build a reduced sample,
decontaminated of the clusters younger than 10Gyr, those with retrograde orbits
and/or evidence of relation to dwarf galaxies. The 33 metal-rich globular
clusters of the reduced sample extend basically to the Solar circle and
distribute over a region with projected axial-ratios typical of an oblate
spheroidal, $\rm\Delta x:\Delta y:\Delta z\approx1.0:0.9:0.4$. The 81
metal-poor globular clusters span a nearly spherical region of axial-ratios
$\approx1.0:1.0:0.8$ extending from the central parts to the outer halo. A new
estimate of the Sun's distance to the Galactic center is provided, $\rm
R_O=7.2\pm0.3 kpc$. The metal-rich and metal-poor radial-density distributions
flatten for $\rm R_{GC}\leq2 kpc$ and are well represented both by a power-law
with a core-like term and S\'ersic's law; at large distances they fall off as
$\rm\sim R^{-3.9}$. Both metallicity components appear to have a common origin,
which is different from that of the dark matter halo. Structural similarities
of the metal-rich and metal-poor radial distributions with the stellar halo are
consistent with a scenario where part of the reduced sample was formed in the
primordial collapse, and part was accreted in an early period of merging. This
applies to the bulge as well, suggesting an early merger affecting the central
parts of the Galaxy. We estimate that the present globular cluster population
corresponds to $\rm\leq23\pm6%$ of the original one. The fact that the
volume-density radial distributions of the metal-rich and metal-poor globular
clusters of the reduced sample follow both a core-like power-law and S\'ersic's
law indicates that we are dealing with spheroidal subsystems in all scales.


title:
Dark matter with invisible light from heavy double charged leptons of
  almost-commutative geometry?

abstract:
  A new candidate of cold dark matter arises by a novel elementary particle
model: the almostcommutative AC-geometrical framework. Two heavy leptons are
added to the Standard Model, each one sharing a double opposite electric charge
and an own lepton flavor number The novel mathematical theory of
almost-commutative geometry [1] wishes to unify gauge models with gravity. In
this scenario two new heavy (m_L>100GeV), oppositely double charged leptons
(A,C),(A with charge -2 and C with charge +2), are born with no twin quark
companions. The model naturally involves a new U(1) gauge interaction,
possessed only by the AC-leptons and providing a Coulomblike attraction between
them. AC-leptons posses electro-magnetic as well as Z-boson interaction and,
according to the charge chosen for the new U(1) gauge interaction, a new
"invisible light" interaction. Their final cosmic relics are bounded into
"neutral" stable atoms (AC) forming the mysterious cold dark matter, in the
spirit of the Glashow's Sinister model. An (AC) state is reached in the early
Universe along a tail of a few secondary frozen exotic components. They should
be now here somehow hidden in the surrounding matter. The two main secondary
manifest relics are C (mostly hidden in a neutral (Cee) "anomalous helium"
atom, at a 10-8 ratio) and a corresponding "ion" A bounded with an ordinary
helium ion (4He); indeed the positive helium ions are able to attract and
capture the free A fixing them into a neutral relic cage that has nuclear
interaction (4HeA).


title:
Approximation of lateral distribution of atmospheric Cherenkov light at
  different observation levels for different primary particles. Applications
  for cosmic ray studies

abstract:
  This work summarizes the results presented at 29th International Cosmic Ray
Conference in Pune India. Generally the aim of this work is to obtain the
lateral distribution of the atmospheric Cherenkov light in extensive air
showers produced by different primary particles in wide energy range and at
several observation levels and to fit the obtained lateral distributions. Using
one large detector and partially modified CORSIKA code version are obtained the
lateral distributions of Cherenkov light flux densities at several observation
levels for different particle primaries precisely at 536 g/cm2 Chacaltaya, 700
g/cm2 Moussala and 875 g/cm2 Kartalska field observation levels for hadronic
primaries and gamma quanta in the energy range 1011 eV-1016 eV. On the basis of
the solution of over-determined inverse problem the approximation of these
distributions is obtained. The same model function for all the primaries is
used and for the different observation levels. The different model parameters
for the different primaries and levels are obtained. The approximations are
compared with polynomial approximation obtained with different method. Both
approximations are used for detector efficiency estimation for the different
experiments in preparation and estimation of the accuracy of the reconstruction
techniques. At the same time inclined showers up to 30 degrees zenith angle are
studied at Chacaltaya observation level. The obtained lateral distributions of
vertical showers are compared with vertical showers model and the previously
obtained approximation. This permits to adjust the reconstruction strategy and
to study the model parameters behavior.


title: The Capture of Centaurs as Trojans

abstract:
  Large scale simulations of Centaurs have yielded vast amounts of data, the
analysis of which allows interesting but uncommon scenarios to be studied. One
such rare phenomenon is the temporary capture of Centaurs as Trojans of the
giant planets. Such captures are generally short (10 kyr to 100 kyr), but occur
with sufficient frequency (about 40 objects larger than 1 km in diameter every
Myr) that they may well contribute to the present-day populations. Uranus and
Neptune seem to have great difficulty capturing Centaurs into the 1:1
resonance, while Jupiter captures some, and Saturn the most (80 %). We
conjecture that such temporary capture from the Centaur population may be the
dominant delivery route into the Saturnian Trojans. Photometric studies of the
Jovian Trojans may reveal outliers with Centaur-like as opposed to asteroidal
characteristics, and these would be prime candidates for captured Centaurs.


title: Fractal Properties and Small-scale Structure of Cosmic String Networks

abstract:
  We present results from a detailed numerical study of the small-scale and
loop production properties of cosmic string networks, based on the largest and
highest resolution string simulations to date. We investigate the non-trivial
fractal properties of cosmic strings, in particular, the fractal dimension and
renormalised string mass per unit length, and we also study velocity
correlations. We demonstrate important differences between string networks in
flat (Minkowski) spacetime and the two very similar expanding cases. For high
resolution matter era network simulations, we provide strong evidence that
small-scale structure has converged to `scaling' on all dynamical lengthscales,
without the need for other radiative damping mechanisms. We also discuss
preliminary evidence that the dominant loop production size is also approaching
scaling.


title: Near-infrared imaging polarimetry of dusty young stars

abstract:
  We have carried out JHK polarimetric observations of eleven dusty young
stars, by using the polarimeter module IRPOL2 with the near-IR camera UIST on
the 3.8-m United Kingdom Infrared Telescope (UKIRT). Our sample targeted
systems for which UKIRT-resolvable discs had been predicted by model fits to
their spectral energy distributions. Our observations have confirmed the
presence of extended polarized emission around TW Hya and around HD 169142. HD
150193 and HD 142666 show the largest polarization values among our sample, but
no extended structure was resolved. By combining our observations with HST
coronographic data from the literature, we derive the J- and H-band intrinsic
polarization radial dependences of TW Hya's disc. We find the disc's polarizing
efficiency is higher at H than at J, and we confirm that the J- and H-band
percentage polarizations are reasonably constant with radius in the region
between 0.9 and 1.3 arcseconds from the star. We find that the objects for
which we have detected extended polarizations are those for which previous
modelling has suggested the presence of flared discs, which are predicted to be
brighter than flat discs and thus would be easier to detect polarimetrically.


title:
The IMF and Star Formation History of the Stellar Clusters in the Vela D
  Cloud

abstract:
  We present the results of a Near-Infrared deep photometric survey of a sample
of six embedded star clusters in the Vela-D molecular cloud, all associated
with luminous (~10^3 Lsun) IRAS sources. The clusters are unlikely to be older
than a few 10^6 yrs, since all are still associated with molecular gas. We
employed the fact that all clusters lie at the same distance and were observed
with the same instrumental setting to derive their properties in a consistent
way, being affected by the same instrumental and observational biases. We
extracted the clusters' K Luminosity Functions (KLF) and developed a simple
method to correct them for extinction, based on colour-magnitude diagrams. The
reliability of the method has been tested by constructing synthetic clusters
from theoretical tracks for pre-main sequence stars and a standard Initial Mass
Function (IMF). The clusters' IMFs have been derived from the dereddened KLFs
by adopting a set of pre-main sequence evolutionary tracks and assuming coeval
star formation. All clusters are small (~100 members) and compact (radius
\~0.1-0.2 pc); their most massive stars are intermediate-mass (~2-10 Msun)
ones. The dereddened KLFs are likely to arise from the same distribution,
suggesting that the selected clusters have quite similar IMFs and star
formation histories. The IMFs are consistent with those derived for field stars
and clusters. Adding them together we found that the ``global'' IMF appears
steeper at the high-mass end and exhibits a drop-off at ~10 Msun. In fact, a
standard IMF would predict a star with M>22.5 Msun within one of the clusters,
which is not found. Hence, either high-mass stars need larger clusters to be
formed, or the IMF of the single clusters is steeper at the high-mass end
because of the physical conditions in the parental gas.


title: On the correlation of Short Gamma--Ray Bursts and Clusters of galaxies

abstract:
  We cross correlate Gamma--Ray Bursts and X--Ray selected clusters of galaxies
at z\leq0.45. We find a positive 2\sigma signal for the angular
cross--correlation function w_{bc}(\theta) on scales \theta\leq 3 deg between
short GRBs and clusters. Conversely, no correlation is found between clusters
and the population of long GRBs. The comparison with the cluster
autocorrelation function shows that short GRBs do not trace the cluster
distribution as not all short GRBs are found in clusters. A higher signal in
w_{bc}(\theta) is found if we only consider the cluster population up to z=0.1.
By comparing the short burst autocorrelation function with model predictions we
then constrain short bursts to mostly originate within \sim 270 Mpc (i.e. z\leq
0.06). Our analysis also reveals that short GRBs are better correlated with
``normal'' galaxies. The double compact object merger model for short GRBs
would associate them preferentially to early--type galaxies but the present
statistics do not allow us to exclude that at least a fraction of these events
might also take place in late--type galaxies, in agreement with recent
evidences.


title: Composite dark matter from 4th generation

abstract:
  Hypothesis of heavy stable quark of 4th family can provide a nontrivial
solution for cosmological dark matter if baryon asymmetry in 4th family has
negative sign and the excess of anti-U quarks with charge (-2/3) is generated
in early Universe. Excessive anti-U antiquarks form (\bar U \bar U \bar U)
antibaryons with electric charge -2, which are all captured by ^4He and trapped
in [^4He^{++}(\bar U \bar U \bar U)^{--}] O-helium (OHe) ``atom'', as soon as
He-4 is formed in Big Bang Nucleosynthesis. Interaction of O-helium with nuclei
opens new path to creation heavy nuclides in Big Bang nucleosynthesis. Due to
large mass of U quark, (OHe) ``atomic'' gas decouples from baryonic matter and
plays the role of dark matter in large scale structure formation with
structures in small scales being suppressed. Owing to nuclear interaction with
matter cosmic O-helium from galactic dark matter halo are slowed down in Earth
below the thresholds of underground dark matter detectors. However,
experimental test of this hypothesis is possible in search for (OHe) in
balloon-borne experiments and for $U$ hadrons in cosmic rays and accelerators.
(OHe) ``atoms'' might form anomalous isotopes and can cause cold nuclear
transformations in matter, offering possible way to exclude (or prove?) their
existence.


title:
The Hot Gas Environment of the Radio Galaxy 3C 388: Quenching the
  Accumulation of Cool Gas in a Cluster Core by a Nuclear Outburst

abstract:
  We present results from a 35 ks {\em Chandra}/ACIS-I observation of the hot
ICM around the FR II radio galaxy 3C 388. 3C 388 resides in a cluster
environment with an ICM temperature of $\sim$3.5 keV. We detect cavities in the
ICM coincident with the radio lobes. The enthalpy of these cavities is
$\sim1.2\times10^{60}$ ergs. The work done on the gas by the inflation of the
lobes is $\sim3\times10^{59}$ ergs, or $\sim$0.87 keV per particle out to the
radius of the lobes. The radiative timescale for gas at the center of the
cluster at the current temperature is a few Gyrs. The gas in the core was
probably cooler and denser before the outburst, so the cooling time was
considerably shorter. We are therefore likely to be witnessing the quenching of
a cluster cooling flow by a radio galaxy outburst. The mechanical power of the
lobes is at least 20 times larger than the radiative losses out to the cooling
radius. Outbursts of similar power with a $\sim$5% duty cycle would be more
than sufficient to continually reheat the cluster core over the Hubble time and
prevent the cooling of any significant amount of gas. The mechanical power of
the outburst is also roughly two orders of magnitude larger than either the
X-ray luminosity of the active nucleus or the radio luminosity of the lobes.
The equipartition pressure of the radio lobes is more than an order of
magnitude lower than that of the ambient medium, indicating that the pressure
of the lobe is dominated by something other than the relativistic electrons
radiating at GHz frequencies.


title:
Radio-ejection and bump-related orbital period gap of millisecond binary
  pulsars

abstract:
  The monotonic increase of the radius of low mass stars during their ascent on
the red giant branch halts when they suffer a temporary contraction. This
occurs when the hydrogen burning shell reaches the discontinuity in hydrogen
content left from the maximum increase in the convective extension, at the time
of the first dredge up, and produces a well known "bump" in the luminosity
function of the red giants of globular clusters. If the giant is the mass
losing component in a binary in which mass transfer occurs on the nuclear
evolution time scale, this event produces a temporary stop in the mass
transfer, which we will name "bump related" detachment. If the accreting
companion is a neutron star, in which the previous mass transfer has spun up
the pulsar down to millisecond periods, the subsequent mass transfer phase may
be altered by the presence of the energetic pulsar. In fact, the onset of a
radio--ejection phase produces loss of mass and angular momentum from the
sytem. We show that this sequence of events may be at the basis of the shortage
of systems with periods between ~ 20 and 60 days in the distribution of
binaries containing millisecond pulsars. We predict that systems which can be
discovered at periods into the gap should have preferentially either magnetic
moments smaller than ~ 2 x10^{26}Gcm^3, or larger than ~ 4x10^{26}Gcm^3. We
further show that this period gap should not be present in population II.


title: On the Lengths, Colors and Ages of 18 Face-On Bars

abstract:
  Along with a brief analysis we present data obtained from BVRI and Ks images
of a sample of 19 galaxies (18 barred and 1 unbarred) which will be further
explored in a future paper. We measured the lengths and colors of the bars,
created color maps and estimated global color gradients. Applying a method
developed in a companion paper, we could distinguish for 7 galaxies in our
sample those whose bars have been recently formed from the ones with already
evolved bars. We estimated an average difference in the optical colors between
young and evolved bars that may be translated to an age difference of the order
of 10 Gyr, meaning that bars may be, at least in some cases, long standing
structures. Moreover, our results show that, on average, evolved bars are
longer than young bars. This seems to indicate that, during its evolution, a
bar grows longer by capturing stars from the disk, in agreement with recent
numerical and analytical results. Although the statistical significance of
these results is low, and further studies are needed to confirm them, we
discuss the implications from our results on the possibility of bars being a
recurrent phenomenon. We also present isophotal contours for all our images as
well as radial profiles of relevant photometric and geometric parameters.


title: Observations of Ultra-High Energy Cosmic Rays

abstract:
  The status of measurements of the arrival directions, mass composition and
energy spectrum of cosmic rays above 3 x 10^18 eV (3 EeV) is reviewed using
reports presented at the 29th International Cosmic Ray Conference held in Pune,
India, in August 2005. The paper is based on a plenary talk given at the
TAUP2005 meeting in Zaragoza, 10 - 14 September 2005.


title: Ionization structure in the disks and winds of B[e] stars

abstract:
  We investigate the ionization structure in the non-spherical winds and disks
of B[e] stars. Especially the luminous B[e] supergiants seem to have outflowing
disks which are neutral in hydrogen already close to the stellar surface. The
existence of neutral material so close to the central star is surprising and
needs to be investigated in detail. We perform our model calculations mainly in
the equatorial plane, trying to find a plausible scenario that leads to
recombination in the vicinity of the hot stars. Two different approaches are
presented that both result in a hydrogen neutral equatorial region. We
especially focus on the influence of stellar rotation which is known to play a
significant role in shaping non-spherical winds. We show that a rotating star
can have a neutral equatorial wind, even without the need of a density
enhancement due to bi-stability or wind compression, but simply due to
graviational darkening in combination with the known high mass-loss rates of
the B[e] stars and especially the B[e] supergiants.


title: Multivariate Non-Normality in the WMAP 1st Year Data

abstract:
  The extraction of cosmological parameters from microwave background
observations relies on specific assumptions about the statistical properties of
the data, in particular that the p-point distributions of temperature
fluctuations are jointly-normal. Using a battery of statistical tests, we
assess the multivariate Gaussian nature of the Wilkinson Microwave Anisotropy
Probe (WMAP) 1st year data. The statistics we use fall into three classes which
test different aspects of joint-normality: the first set assess the normality
of marginal (one-point) distributions using familiar univariate methods; the
second involves statistics that directly assess joint-normality; and the third
explores the evidence of non-linearity in the relationship between variates. We
applied these tests to frequency maps, `foreground-cleaned' assembly maps and
all-sky CMB-only maps. The assembly maps are of particular interest as when
combined with the kp2 mask, we recreate the region used in the computation of
the angular power spectrum. Significant departures from normality were found in
all the maps. In particular, the kurtosis coefficient, D'Agostino's statistic
and bivariate kurtosis calculated from temperature pairs extracted from all the
assembly maps were found to be non-normal at 99% confidence level. We found
that the results were unaffected by the size of the Galactic cut and were
evident on either hemisphere of the CMB sky. The latter suggests that the
non-Gaussianity is not simply related to previous claims of north-south
asymmetry or localized abnormalities detected through wavelet techniques.


title: Dense plasmas in astrophysics: from giant planets to neutron stars

abstract:
  We briefly examine the properties of dense plasmas characteristic of the
interior of giant planets and the atmospheres of neutron stars. Special
attention is devoted to the equation of state of hydrogen and helium at high
density and to the effect of magnetic fields on the properties of dense matter.


title: Discovery of eleven new ZZ Ceti stars

abstract:
  We report the discovery of eleven new ZZ Cetis using telescopes at OPD
(Observat\'orio do Pico dos Dias/LNA) in Brazil, the 4.1 m SOAR (Southern
Astrophysical Research) telescope at Cerro Pachon, Chile, and the 2.1 m Otto
Struve telescope at McDonald observatory. The candidates were selected from the
SDSS (Sloan Digital Sky Survey) and SPY (ESO SN Ia progenitor survey), based on
their Teff obtained from optical spectra fitting. This selection criterion
yields the highest success rate of detecting new ZZ Cetis, above 90% in the
Teff range from 12000 to 11000 K. We also report on a DA not observed to vary,
with a Teff placing the star close to the blue edge of the instability strip.
Among our new pulsators, one is a little bit cooler than this star for which
pulsations were not detected. Our observations are an important constraint on
the location of the blue edge of the ZZ Ceti instability strip.


title: Dark Matter Searches

abstract:
  More than 90% of matter in the Universe could be composed of heavy particles,
which were non-relativistic, or 'cold', when they froze-out from the primordial
soup. I will review current searches for these hypothetical particles, both via
interactions with nuclei in deep underground detectors, and via the observation
of their annihilation products in the Sun, galactic halo and galactic center.


title: Constraints on the Progenitor of Cassiopeia A

abstract:
  We compare a suite of 3D explosion calculations and stellar models
incorporating advanced physics with observational constraints on the progenitor
of Cassiopeia A. We consider binary and single stars from 16 to 40 solar masses
with a range of explosion energies and geometries. The parameter space allowed
by observations of nitrogen rich high velocity ejecta, ejecta mass, compact
remnant mass, and 44Ti and 56Ni abundances individually and as an ensemble is
considered. A progenitor of 15-25 solar masses which loses its hydrogen
envelope to a binary interaction and undergoes an energetic explosion can match
all the observational constraints.


title: Discovery of a Planetary-Mass Brown Dwarf with a Circumstellar Disk

abstract:
  Using the Hubble Space Telescope, the 4 m Blanco telescope at the Cerro
Tololo Inter-American Observatory, and the Spitzer Space Telescope, we have
performed deep imaging from 0.8 to 8 um of the southern subcluster in the
Chamaeleon I star-forming region. In these data, we have discovered an object,
Cha 110913-773444, whose colors and magnitudes are indicative of a very
low-mass brown dwarf with a circumstellar disk. In a near-infrared spectrum of
this source obtained with the Gemini Near-Infrared Spectrograph, the presence
of strong steam absorption confirms its late-type nature (>=M9.5) while the
shapes of the H- and K-band continua and the strengths of the Na I and K I
lines demonstrate that it is a young, pre-main-sequence object rather than a
field dwarf. A comparison of the bolometric luminosity of Cha 110913-773444 to
the luminosities predicted by the evolutionary models of Chabrier and Baraffe
and Burrows and coworkers indicates a mass of 8+7/-3 M_Jup, placing it fully
within the mass range observed for extrasolar planetary companions (M<=15
M_Jup). The spectral energy distribution of this object exhibits mid-infrared
excess emission at >5 um, which we have successfully modeled in terms of an
irradiated viscous accretion disk with M'<=10e-12 M_sun/year. Cha 110913-773444
is now the least massive brown dwarf observed to have a circumstellar disk, and
indeed is one of the least massive free-floating objects found to date. These
results demonstrate that the raw materials for planet formation exist around
free-floating planetary-mass bodies.


title:
Post-WMAP Assessment of Infrared Cutoff in the Primordial Spectrum from
  Inflation

abstract:
  The recent Cosmic Microwave Background (CMB) measurements indicate that there
is power deficiency of the CMB anisotropies at large scales compared with the
$\Lambda$CDM model. We have investigated the possibility of explaining such
effects by a class of primordial power spectra which have infrared cutoffs
close to the horizon scale. The primordial power spectrum recovered by direct
deconvolution of the observed CMB angular spectrum indicates that the data
prefers a sharp infrared cutoff with a localized excess (bump) just above the
cutoff. We have been motivated to assess plausible extensions of simplest
inflationary scenarios which readily accommodate similar form of infrared
cutoff. We carry out a complete Bayesian analysis of the parameter space using
{\it Markov Chain Monte Carlo} technique with such a class of primordial power
spectra. We show that primordial power spectrum that have features such as an
infrared cutoff followed by a subsequent excess in power give better fit to the
observed data compared to a nearly scale-invariant power law or power spectrum
with just a monotonic infrared cutoff. However, there is substantial room for
improvement in the match to data and calls for exploration of other mechanisms
that may lead to infrared cutoff even closer to that recovered by direct
deconvolution approach.


title:
The [OII]/Halpha ratio of emission line galaxies in the 2dF redshift
  survey

abstract:
  We investigate the systematic variation of the [OII]3727/Halpha flux line
ratio as a function of various galaxy properties, i.e., luminosity,
metallicity, reddening, and excitation state, for a sample of 1124
emission-line galaxies, with a mean redshift z ~ 0.06, drawn from the Two
Degree Field Galaxy Redshift Survey. The mean observed and extinction-corrected
emission-line flux ratios agree well with the values derived from the $B$-band
selected Nearby Field Galaxy Survey galaxy sample, but are significantly
different from the values obtained from the Halpha-selected Universidad
Complutense de Madrid Survey galaxy sample. This is because the different
selection criteria applied in these surveys lead to a significant difference in
the mean extinction and metallicity of different samples. We use the R_{23}
parameter to estimate the gas-phase oxygen abundance and find that the
extinction-corrected [OII]3727/Halpha ratio depends on the oxygen abundance.
For 12+log(O/H)>8.4, we confirm that the emission-line ratio decreases with
increasing metallicity. We have extended the relationship further to the
metal-poor regime, 12+log(O/H)< 8.4, and find that the correlation between the
extinction-corrected [OII]3727/Halpha ratio and the metallicity reverses in
comparison to the relationship for metal-rich galaxies. For metal-poor
galaxies, in contrast with metal-rich ones, the variation of
extinction-corrected [OII]3727/Halpha ratio is correlated with the ionization
states of the interstellar gas.


title: The Smallest AGN Host Galaxies

abstract:
  We describe our efforts to study dwarf galaxies with active nuclei, whose
black holes, with masses < 10^6 M_sun, provide the best current observational
constraints on the mass distribution of primordial seed black holes. Although
these low-mass galaxies do not necessarily contain classical bulges, Barth,
Greene, & Ho (2005) show that their stellar velocity dispersions and black hole
masses obey the same relation as more massive systems. In order to characterize
the properties of the dwarf hosts without the glare of the active nucleus, we
have compiled a complementary sample of narrow-line active galaxies with
low-mass hosts. The host galaxy properties, both their structures and stellar
populations, are consistent with the general properties of low-mass, blue
galaxies from Sloan. The black holes in these galaxies are probably radiating
close to their Eddington limits, suggesting we may have found Type 2 analogues
of narrow-line Seyfert 1 galaxies.


title: Compact Object Modeling with the StarTrack Population Synthesis Code

abstract:
  We present a comprehensive description of the population synthesis code
StarTrack. The original code has been significantly modified and updated.
Special emphasis is placed here on processes leading to the formation and
further evolution of compact objects (white dwarfs, neutron stars, and black
holes). Both single and binary star populations are considered. The code now
incorporates detailed calculations of all mass-transfer phases, a full
implementation of orbital evolution due to tides, as well as the most recent
estimates of magnetic braking. This updated version of StarTrack can be used
for a wide variety of problems, with relevance to many current and planned
observatories, e.g., studies of X-ray binaries (Chandra, XMM-Newton),
gravitational radiation sources (LIGO, LISA), and gamma-ray burst progenitors
(HETE-II, Swift). The code has already been used in studies of Galactic and
extra-galactic X-ray binary populations, black holes in young star clusters,
Type Ia supernova progenitors, and double compact object populations. Here we
describe in detail the input physics, we present the code calibration and
tests, and we outline our current studies in the context of X-ray binary
populations.


title: Astrophysical Gyrokinetics: Basic Equations and Linear Theory

abstract:
  Magnetohydrodynamic (MHD) turbulence is encountered in a wide variety of
astrophysical plasmas, including accretion disks, the solar wind, and the
interstellar and intracluster medium. On small scales, this turbulence is often
expected to consist of highly anisotropic fluctuations with frequencies small
compared to the ion cyclotron frequency. For a number of applications, the
small scales are also collisionless, so a kinetic treatment of the turbulence
is necessary. We show that this anisotropic turbulence is well described by a
low frequency expansion of the kinetic theory called gyrokinetics. This paper
is the first in a series to examine turbulent astrophysical plasmas in the
gyrokinetic limit. We derive and explain the nonlinear gyrokinetic equations
and explore the linear properties of gyrokinetics as a prelude to nonlinear
simulations. The linear dispersion relation for gyrokinetics is obtained and
its solutions are compared to those of hot-plasma kinetic theory. These results
are used to validate the performance of the gyrokinetic simulation code {\tt
GS2} in the parameter regimes relevant for astrophysical plasmas. New results
on global energy conservation in gyrokinetics are also derived. We briefly
outline several of the problems to be addressed by future nonlinear
simulations, including particle heating by turbulence in hot accretion flows
and in the solar wind, the magnetic and electric field power spectra in the
solar wind, and the origin of small-scale density fluctuations in the
interstellar medium.


title: The Nature of the Faint Chandra X-ray Sources in the Galactic Centre

abstract:
  Recent Chandra observations have revealed a large population of faint X-ray
point sources in the Galactic Centre. The observed population consists of about
2000 faint sources in the luminosity range ~10^31-10^33 erg/s. The majority of
these sources (70%) are described by hard spectra, while the rest are rather
soft. The nature of these sources still remains unknown. Belczynski & Taam
(2004) demonstrated that X-ray binaries with neutron star or black hole
accretors may account for most of the soft sources, but are not numerous enough
to account for the observed number and X-ray properties of the faint hard
sources. A population synthesis calculation of the Galactic Centre region has
been carried out. Our results indicate that the numbers and X-ray luminosities
of intermediate polars are consistent with the observed faint hard Galactic
Centre population.


title: Viscous generalized Chaplygin gas

abstract:
  Viscous GCG(generalized Chaplygin gas) cosmology is discussed, assuming that
there is bulk viscosity in the barotropic fluid and GCG. The dynamical analysis
indicates that the phase
$w_g=-1+\sqrt{3}\gamma\kappa\tau_{g}/(\gamma-\sqrt{3}\kappa\tau_{\gamma})$ is a
dynamical attractor and the equation of state of GCG approaches it from either
$w_g>-1$ or $w_g<-1$ depending on the choice of its initial cosmic density
parameter and the ratio of pressure to critical energy density. Obviously, the
equation of state $w_g$ can cross the boundary $w_g=-1$. Also, from the point
of view of dynamics, the parameters of viscous GCG should be in the range of
$\gamma>\sqrt{3}\kappa\tau_{\gamma}/(1-\sqrt{3}\kappa\tau_{g})$ and
$0<\alpha<1+\sqrt{3}
\kappa\gamma\tau_{g}/(\gamma-\sqrt{3}\kappa\tau_{\gamma}-\sqrt{3}\kappa\gamma\t
au_{g})$.


title: Infrared spectroscopy of solid CO-CO2 mixtures and layers

abstract:
  The spectra of pure, mixed and layered CO and CO2 ices have been studied
systematically under laboratory conditions using infrared spectroscopy. This
work provides improved resolution spectra (0.5 cm-1) of the CO2 bending and
asymmetric stretching mode, as well as the CO stretching mode, extending the
existing Leiden database of laboratory spectra to match the spectral resolution
reached by modern telescopes and to support the interpretation of the most
recent data from Spitzer. It is shown that mixed and layered CO and CO2 ices
exhibit very different spectral characteristics, which depend critically on
thermal annealing and can be used to distinguish between mixed, layered and
thermally annealed CO-CO2 ices. CO only affects the CO2 bending mode spectra in
mixed ices below 50K under the current experimental conditions, where it
exhibits a single asymmetric band profile in intimate mixtures. In all other
ice morphologies the CO2 bending mode shows a double peaked profile, similar to
that observed for pure solid CO2. Conversely, CO2 induces a blue-shift in the
peak-position of the CO stretching vibration, to a maximum of 2142 cm-1 in
mixed ices, and 2140-2146 cm-1 in layered ices. As such, the CO2 bending mode
puts clear constraints on the ice morphology below 50K, whereas beyond this
temperature the CO2 stretching vibration can distinguish between initially
mixed and layered ices. This is illustrated for the low-mass YSO HH46, where
the laboratory spectra are used to analyse the observed CO and CO2 band
profiles and try to constrain the formation scenarios of CO2.


title:
The Non-Parametric Model for Linking Galaxy Luminosity with Halo/Subhalo
  Mass

abstract:
  We present a non-parametric, empirically based, model for associating galaxy
luminosities with halo/subhalo masses, based on a self-consistent treatment of
subhalo mass loss and the subhalo mass function. We find that, at high mass,
the mass-luminosity relation is almost independent of the actual luminosity
function considered, when luminosity is scaled by the characteristic luminosity
L*. Additionally, the shape of the total halo luminosity depends on the slope
of the subhalo mass function. For these high mass, cluster sized haloes, we
find that total luminosity scales as L_tot ~ M^0.88, while the luminosity of
the first brightest galaxy has a much weaker dependence on halo mass, L_1 ~
M^0.28, in good agreement with observations and previous results. At low mass,
the resulting slope of the mass-luminosity relation depends strongly of the
faint end slope of the luminosity function, and we obtain a steep relation,
with approximately L ~ M^4.5 in the K-band. The average number of galaxies per
halo/cluster is also in very good agreement with observations, scaling as
M^0.9. In general, we obtain a good agreement with several independent sets of
observational data. We find that, when comparing with observations and for a
flat cosmology, the model tends to prefer lower values for Omega_m and sigma_8.
Within the WMAP+SDSS concordance plane of Tegmark et al. (2004), we find best
agreement around Omega_m=0.25 and sigma_8=0.8, also in very good agreement with
the results of the CMB+2dF study of Sanchez et al. (2005). We also check on
possible corrections for observed mass based on a comparison of the equivalent
number of haloes/clusters. Additionally, we include further checks on the model
results based on the mass to light ratio, the occupation number, the group
luminosity function and the multiplicity function. (abridged)


title: On the force-free magnetosphere of aligned rotator

abstract:
  We investigate in details properties of stationary force-free magnetosphere
of aligned rotator assuming the last closed field line lying in equatorial
plane at large distances from pulsar. The pulsar equations is solved
numerically using multigrid code with high numerical resolution, physical
properties of the magnetosphere are obtained with high accuracy. We found a set
of solutions with different sizes of the closed magnetic field line zone and
verify the applicability of the force-free approximation. We discuss the role
of electron-positron cascades in supporting of the force-free magnetosphere and
argue that the closed field line zone should grow with time slower than the
light cylinder. This yield the pulsar breaking index less than 3. It is shown,
that models of aligned rotator magnetosphere with widely accepted configuration
of magnetic field, like one considered in this paper, have serious
difficulties. We discuss solutions of this problem and argue that in any case
pulsar energy losses should evolve with time differently than predicted by the
magnetodipolar formula.


title: A dichotomy in radio jet orientations

abstract:
  We examine the relative orientations of radio jets, central dust and stars in
low-power (i.e., FR I and FR I/II) radio galaxies. We use the position angles
of jet and dust to constrain the three-dimensional angle $\theta_{\rm DJ}$
between jet and dust. For galaxies with filamentary dust 'lanes' (which tend to
be misaligned with the galaxy major axis) the jet is approximately
perpendicular to the dust structure, while for galaxies with elliptical dust
distributions (typically aligned with the galaxy major axis) there is a much
wider distribution of $\theta_{\rm DJ}$. nThe dust ellipses are consistent with
being nearly circular thin disks viewed at random viewing angles. The lanes are
likely warped, unsettled dust structures. We consider two scenarios to explain
the dust/jet orientation dichotomy.


title:
The optical and IR properties of southern galactic unclB[e] stars: The
  case of CD-42 11721

abstract:
  (abridged) In this work we present the results of an optical and IR study for
the curious B[e] star CD-42 11721. This object has a doubtful evolutionary
stage, being either a pre-main sequence star (HAeB[e]) or an evolved star
(sgB[e]). Our optical investigation could be splitted in two parts, a
qualitative study based on the identification of the numerous emission lines
present in the spectra and the classification of their line profiles, which
indicate a non-spherically symmetric circumstellar environment, and a
quantitative analysis of numerous forbidden lines, e.g. [OI], [OII], [NII] and
[SII]. Assuming a typical circumstellar scenario for a sgB[e], i.e. a fast,
low-density polar wind and a slow, high-density disc forming equatorial wind,
we can reproduce very well the line luminosities of the forbidden lines. From
this analysis, we can determine the mass loss rate of the star lying in the
range from 4.4 x 10^(-6) to 2.2 x 10^(-5) M_sun/yr, depending on the considered
redenning. Our IR study could also be splitted in two parts: the identification
of several features in the SWS ISO spectrum, and the modeling of the SED of
CD-42 11721. The first part shows the presence of a mixed chemistry, i.e. C-
and O-rich dust in the same circumstellar medium. We have tried to model the
SED, by using a numerical code written by us which considers a spherical
circumstellar scenario. Although the answer concerning the evolutionary stage
of CD-42 11721 is still not very clear, we believe that our analysis will
improve the discussion about the nature of this curious star.


title: The compact planetary nebula B[e] star Hen 2-90

abstract:
  We present a study of the optical spectrum of the fascinating B[e] star Hen
2-90 based on new high-resolution observations taken with FEROS at the ESO
1.52m telescope in La Silla (Chile). The recent HST image of Hen 2-90 (Sahai et
al. 2002) reveals a bipolar, highly ionized region, a neutral disk-like
structure seen almost perfectly edge-on, and an intermediate region of moderate
ionization. The slits of our observations cover the same innermost region of
Hen 2-90 as the HST image, which allows us to combine the observations. Our
spectra contain a huge amount of permitted and forbidden emission lines of
atoms in different stages of ionization. In addition, the line wings deliver
velocity information of the emitting region. We find correlation between the
different ionization states of the elements and the velocities derived from the
line profiles: the highly ionized atoms have the highest outflow velocity,
while the neutral lines have the lowest. When combining the velocity
information with the HST image of Hen 2-90, it seems that a non-spherical
stellar wind model is a good option to explain the ionization and spatial
distribution of the circumstellar material. Our modeling of the forbidden
emission lines results in strong evidence for Hen 2-90 being a compact
planetary nebulae that has undergone a superwind phase of high, non-spherical
mass loss, most probably triggered by a central star that was rotating with
about 80% of the critical velocity. We find a total mass loss rate during this
superwind phase on the order of 3 x 10^(-5) M_sun/yr.


title:
Dark Energy Evolution and the Curvature of the Universe from Recent
  Observations

abstract:
  We discuss the constraints on the time-varying equation of state for dark
energy and the curvature of the universe using observations of type Ia
supernovae from Riess et al. and the most recent Supernova Legacy Survey
(SNLS), the baryon acoustic oscillation peak detected in the SDSS luminous red
galaxy survey and cosmic microwave background. Due to the degeneracy among the
parameters which describe the time dependence of the equation of state and the
curvature of the universe, the constraints on them can be weakened when we try
to constrain them simultaneously, in particular when we use a single
observational data. However, we show that we can obtain relatively severe
constraints when we use all data sets from observations above even if we
consider the time-varying equation of state and do not assume a flat universe.
We also found that the combined data set favors a flat universe even if we
consider the time variation of dark energy equation of state.


title: The neutral outflowing disks of some Magellanic Cloud B[e] supergiants

abstract:
  We report on the detection of [OI] emission lines in the high-resolution
optical spectra of several Magellanic Cloud (MC) B[e] supergiants, which we
took with FEROS at the ESO 1.52m telescope in La Silla (Chile). In addition, we
model the [OI] line luminosities and show that the best location for the
neutral oxygen material is the outflowing disk. In order to reproduce the
observed line luminosities, we conclude that the disks must be neutral already
very close to the stellar surface.


title: New Near-Infrared Surface Brightness Fluctuation Models

abstract:
  We present new theoretical models for surface brightness fluctuations in the
near-infrared. We show the time evolution of near-infrared brightness
fluctuation properties over large age and metallicity ranges, i.e., from 12 Myr
to 16 Gyr, and from Z/Zsun=1/50 to Z/Zsun=2.5, for single age, single
metallicity stellar populations. All the stellar models are followed from the
zero age main sequence to the central carbon ignition for massive stars, or to
the end of the thermally pulsing regime of the asymptotic giant branch phase
for low and intermediate mass stars. The new models are compared with observed
near-infrared fluctuation absolute magnitudes and colours for a sample of
Magellanic Cloud star clusters and Fornax Cluster galaxies. For star clusters
younger than ~3 Gyr, the predicted near-infrared fluctuation properties are in
a satisfactory agreement with observed ones over a wide range of stellar
population metallicities. However, for older star clusters, the agreement
between the observed and predicted near-IR brightness fluctuations depends on
how the surface brightness absolute magnitudes are estimated. The computed set
of models are not able to match the observed near-IR fluctuation absolute
magnitudes and colours simultaneously. We argue that the observed discrepancies
between the predicted and observed properties of old MC superclusters are more
likely due to observational reasons.


title:
Hamiltonian General Relativity in Finite Space and Cosmological
  Potential Perturbations

abstract:
  The Hamiltonian formulation of general relativity (GR) is considered in
finite space-time and a specific frame of reference given by the
diffeo-invariant components of the Fock simplex in terms of the Dirac -- ADM
variables. The evolution parameter and energy invariant with respect to the
time-coordinate transformations are constructed by the separation of the
cosmological scale factor and its identification with the spatial averaging of
the metric determinant, so that the dimension of the kinemetric group of
diffeomorphisms coincides with the dimension of a set of variables whose
velocities are removed by the Gauss-type constraints in accordance with the
second N\"other theorem. This coincidence allows us to solve the energy
constraint, fulfil Dirac's Hamiltonian reduction, and to describe the potential
perturbations in terms of the Lichnerowicz scale-invariant variables
distinguished by the absence of the time derivatives of the spatial metric
determinant. It was shown that the Hamiltonian version of the cosmological
perturbation theory acquires attributes of the theory of superfluid liquid, and
it leads to the generalization of the Schwarzschild solution. The astrophysical
application of this approach to GR is considered under supposition that the
Dirac -- ADM Hamiltonian frame is identified with that of the Cosmic Microwave
Background radiation distinguished by its dipole component in the frame of an
Earth observer.


title: The recurrent nova U Scorpii - an evolutionary considerations

abstract:
  We perform evolutionary calculations of binary stars to find progenitors of
systems with parameters similar to the recurrent nova U Sco. We show that a U
Sco-type system may be formed starting with an initial binary system which has
a low-mass carbon-oxygen white dwarf as an accretor. Since the evolutionary
stage of the secondary is not well known, we calculate sequences with
hydrogen-rich and helium-rich secondaries. The evolution of the binary may be
divided into several observable stages as: classical nova, supersoft X-ray
source with stable hydrogen shell burning, or strong wind phase. It culminates
in the formation of a massive white dwarf near the Chandrasekhar mass limit. We
follow the chemical evolution of the secondary as well as of the matter lost
from the system, and we show that observed $^{12}$C/$^{13}$C and N/C ratios may
give some information about the nature of the binary.


title:
Toward Radiation-Magnetohydrodynamic Simulations in Core-Collapse
  Supernovae

abstract:
  We report a current status of our radiation-magnetohydrodynamic code for the
study of core-collapse supernovae. In this contribution, we discuss the
accuracy of our newly developed numerical code by presenting the test problem
in a static background model. We also present the application to the
spherically symmetric core-collapse simulations. Since close comparison with
the previously published models is made, we are now applying it for the study
of magnetorotational core-collapse supernovae.


title: Resolving the pulsations of the subdwarf B star KPD 2109+4401

abstract:
  We present the results of extensive time series photometry of the pulsating
subdwarf B star KPD 2109+4401. Our data set consists of 29 data runs with a
total length of 182.6 hours over 31 days, collected at five observatories in
2004. These data are comprised of high signal-to-noise observations acquired
with larger telescopes and wider time coverage observations obtained with
smaller telescopes. They are sufficient to resolve the pulsation structure to
0.4 $\mu$Hz and are the most extensive data set for this star to date. With
these data, we identify eight pulsation frequencies extending from 4701 to 5481
$\mu$Hz, corresponding to periods of 182 to 213 s. The pulsation frequencies
and their amplitudes are examined over several time-scales with some
frequencies showing amplitude variability.


title: INTEGRAL observation of the X-ray burster KS 1741-293

abstract:
  KS 1741-293 was firstly detected in 1989 with the X-ray wide field camera TTM
(3-10 keV) on board of the Rontgen-Kvant-Mir observatory. During these
observations this source exhibited two X-ray bursts allowing to identify it as
a neutron star in a Low mass X-ray Binary. During the BeppoSAX/WFC monitoring
of the Galactic Centre Region, KS 1741-293 was also reported at a flux level of
6 mCrab in the 2-9 keV and 25 mCrab in the 9-25 keV energy range. Thanks to the
deep and regular INTEGRAL observation of the Galactic Centre region, KS
1741-293 has been observed by the X-ray monitor JEM-X and the imager IBIS in a
wide energy range, giving for the first time relevant information on its high
energy behaviour. Furthermore, two X-ray bursts have been detected by JEM-X. We
report on IBIS and JEM-X data analysis in terms of flux monitoring, spectral
proprieties and bursts detection. The data reduction has been done with the
most recent release of the standard analysis software (OSA 5.0).