title:
Distribution of magnetically confined circumstellar matter in oblique
  rotators

abstract:
  We consider the mechanical equilibrium and stability of matter trapped in the
magnetosphere of a rapidly rotating star. Assuming a dipolar magnetic field and
arbitrary inclination of the magnetic axis with respect to the axis of rotation
we find stable equilibrium positions a) in a (warped) disk roughly aligned with
the magnetic equatorial plane and b) at two locations above and below the disk,
whose distance from the star increases with decreasing inclination angle
between dipole and rotation axis. The distribution of matter is not strongly
affected by allowing for a spatial offset of the magnetic dipole. These results
provide a possible explanation for some observations of corotating localized
mass concentrations in hot magnetic stars.


title:
Far-Ultraviolet Surveys of Globular Clusters: Searching for the Products
  of Stellar Collisions and Near Misses

abstract:
  Far-ultraviolet (FUV) observations with the Hubble Space Telescope are an
excellent way to find and study the hot, blue stellar populations in the cores
of globular clusters. These populations include dynamically-formed blue
stragglers and interacting binaries (such as cataclysmic variables), i.e. the
products of stellar collisions and near misses. Using the cluster 47 Tuc as an
example, we show how the combination of FUV imaging and slitless spectroscopy
can be used to uncover and study these populations.


title: The Interstellar Rubidium Isotope Ratio toward Rho Ophiuchi A

abstract:
  The isotope ratio, 85Rb/87Rb, places constraints on models of the
nucleosynthesis of heavy elements, but there is no precise determination of the
ratio for material beyond the Solar System. We report the first measurement of
the interstellar Rb isotope ratio. Our measurement of the Rb I line at 7800 A
for the diffuse gas toward rho Oph A yields a value of 1.21 +/- 0.30 (1-sigma)
that differs significantly from the meteoritic value of 2.59. The Rb/K
elemental abundance ratio for the cloud also is lower than that seen in
meteorites. Comparison of the 85Rb/K and 87Rb/K ratios with meteoritic values
indicates that the interstellar 85Rb abundance in this direction is lower than
the Solar System abundance. We attribute the lower abundance to a reduced
contribution from the r-process. Interstellar abundances for Kr, Cd, and Sn are
consistent with much less r-process synthesis for the solar neighborhood
compared to the amount inferred for the Solar System.


title:
Revised masses of dust and gas of SLUGS FIR bright galaxies based on a
  recent CO survey

abstract:
  Recent CO measurements of an essentially complete sub-sample of galaxies from
the SCUBA Local Universe Survey (SLUGS) are used to examine their implications
for dust and gas masses in this sample. Estimates of dust masses are affected
by a contribution to the SCUBA brightness measurements by CO(3-2) emission, and
molecular gas masses by the use of a modified value of the CO-to-H_2 conversion
factor X. The average dust mass is reduced by 25-38 per cent, which has no
bearing on earlier conclusions concering the shapes of the dust mass luminosity
function derived from the SLUGS. The value of X found from the CO survey, when
applied together with the reduction in dust masses, leads to lower estimates
for the mean gas-to-dust mass ratios, where the gas includes both H_2 and HI.
For the CO sample, the mean global ratio is reduced from approximately 430 to
about 320-360, but is further reduced to values near 50 when applied to the
nuclear regions relevant to the CO observations. We discuss these results and
suggest that the differences between the nuclear and outer regions may simply
reflect differences in metallicity or the existence of considerable amounts of
unobserved cold dust in the outer regions of these galaxiies.


title: Velocity centroids as tracers of the turbulent velocity statistics

abstract:
  We use the results of magnetohydrodynamic (MHD) simulations to emulate
spectroscopic observations and use maps of centroids to study their statistics.
In order to assess under which circumstances the scaling properties of the
velocity field can be retrieved from velocity centroids, we compare two point
statistics (structure functions and power-spectra) of velocity centroids with
those of the underlying velocity field and analytic predictions presented in a
previous paper (Lazarian & Esquivel 2003). We tested a criterion for recovering
velocity spectral index from velocity centroids derived in our previous work,
and propose an approximation of the early criterion using only the variances of
``unnormalized'' velocity centroids and column density maps. It was found that
both criteria are necessary, however not sufficient to determine if the
centroids recover velocity statistics. Both criteria are well fulfilled for
subsonic turbulence. We find that for supersonic turbulence with sonic Mach
numbers > 2.5 centroids fail to trace the spectral index of velocity.
Asymptotically, however, we claim that recovery of velocity statistics is
always possible provided that the density spectrum is steep and the observed
inertial range is sufficiently extended. In addition, we show that velocity
centroids are useful for anisotropy studies and determining the direction of
magnetic field, even if the turbulence is highly supersonic, but only if it is
sub-Alfvenic. This provides a tool for mapping the magnetic field direction,
and testing whether the turbulence is sub-Alfvenic or super-Alfvenic.


title:
Complex Structure of Galaxy Cluster Abell 1689: Evidence for a Merger
  from X-ray data?

abstract:
  Abell 1689 is a galaxy cluster at $z=0.183$ where previous measurements of
its mass using various techniques gave discrepant results. We present a new
detailed measurement of the mass with the data based on X-ray observations with
the European Photon Imaging Camera aboard the XMM-Newton Observatory,
determined by using an unparameterized deprojection technique. Fitting the
total mass profile to a Navarro-Frenk-White model yields halo concentration
$c=7.2^{+1.6}_{-2.4}$ and $r_{200}=1.13 \pm 0.21 h^{-1} \mathrm{Mpc}$,
corresponding to a mass which is less than half of what is found from
gravitational lensing. Adding to the evidence of substructure from optical
observations, X-ray analysis shows a highly asymmetric temperature profile and
a non-uniform redshift distribution implying large scale relative motion of the
gas. A lower than expected gas mass fraction $f_{gas}=0.072 \pm 0.008$ (for a
flat $\Lambda$CDM cosmology) suggests a complex spatial and/or dynamical
structure. We also find no signs of any additional absorbing component
previously reported on the basis of the Chandra data, confirming the XMM low
energy response using data from ROSAT.


title: Evolution of the Cluster X-ray Luminosity Function

abstract:
  We report measurements of the cluster X-ray luminosity function out to z=0.8
based on the final sample of 201 galaxy systems from the 160 Square Degree
ROSAT Cluster Survey. There is little evidence for any measurable change in
cluster abundance out to z~0.6 at luminosities less than a few times 10^44
ergs/s (0.5-2.0 keV). However, between 0.6 < z < 0.8 and at luminosities above
10^44 ergs/s, the observed volume densities are significantly lower than those
of the present-day population. We quantify this cluster deficit using
integrated number counts and a maximum-likelihood analysis of the observed
luminosity-redshift distribution fit with a model luminosity function. The
negative evolution signal is >3 sigma regardless of the adopted local
luminosity function or cosmological framework. Our results and those from
several other surveys independently confirm the presence of evolution. Whereas
the bulk of the cluster population does not evolve, the most luminous and
presumably most massive structures evolve appreciably between z=0.8 and the
present. Interpreted in the context of hierarchical structure formation, we are
probing sufficiently large mass aggregations at sufficiently early times in
cosmological history where the Universe has yet to assemble these clusters to
present-day volume densities.


title: Analysis of alpha Centauri AB including seismic constraints

abstract:
  Detailed models of alpha Cen A and B based on new seismological data for
alpha Cen B by Carrier & Bourban (2003) have been computed using the Geneva
evolution code including atomic diffusion. Taking into account the numerous
observational constraints now available for the alpha Cen system, we find a
stellar model which is in good agreement with the astrometric, photometric,
spectroscopic and asteroseismic data. The global parameters of the alpha Cen
system are now firmly constrained to an age of t=6.52+-0.30 Gyr, an initial
helium mass fraction Y_i=0.275+-0.010 and an initial metallicity
(Z/X)_i=0.0434+-0.0020. Thanks to these numerous observational constraints, we
confirm that the mixing-length parameter alpha of the B component is larger
than the one of the A component, as already suggested by many authors (Noels et
al. 1991, Fernandes & Neuforge 1995 and Guenther & Demarque 2000): alpha_B is
about 8% larger than alpha_A (alpha_A=1.83+-0.10 and alpha_B=1.97+-0.10).
Moreover, we show that asteroseismic measurements enable to determine the radii
of both stars with a very high precision (errors smaller than 0.3%). The radii
deduced from seismological data are compatible with the new interferometric
results of Kervella et al. (2003) even if they are slightly larger than the
interferometric radii (differences smaller than 1%).


title:
Relativistic spectral features from X-ray illuminated spots and the
  measure of the black hole mass in AGN

abstract:
  Narrow spectral features in the 5--6 keV range were recently discovered in
the X-ray spectra of a few active galactic nuclei. We discuss the possibility
that these features are due to localized spots which occur on the surface of an
accretion disc following its illumination by flares. We present detailed line
profiles as a function of orbital phase of the spot and its radial distance
from a central black hole. Comparison of these computed profiles with observed
features can help to estimate parameters of the system. In principle this
method can provide a powerful tool to measure the mass of super-massive black
holes in active galactic nuclei. By comparing our simulations with the Chandra
and XMM-Newton results, we show, however, that spectra from present generation
X-ray satellites are not of good enough quality to fully exploit the method and
determine the black hole mass with sufficient accuracy. This task has to be
deferred to future missions with high throughput and high energy resolution,
such as Constellation-X and Xeus.


title:
The physics of extrasolar gaseous planets : from theory to observable
  signatures

abstract:
  We review our present understanding of the physical properties of substellar
objects, brown dwarfs and irradiated or non-irradiated gaseous exoplanets. This
includes a description of their internal properties, mechanical structure and
heat content, their atmospheric properties, thermal profile and emergent
spectrum, and their evolution, in particular as irradiated companions of a
close parent star. The general theory can be used to make predictions in term
of detectability for the future observational projects. Special attention is
devoted to the evolution of the two presently detected transit planets,
HD209458B and OGLE-TR-56B. For this latter, we present a consistent evolution
for its recently revised mass and show that we reproduce the observed radius
within its error bars. We briefly discuss differences between brown dwarfs and
gaseous planets, both in terms of mass function and formation process. We
outline several arguments to show that the minimum mass for deuterium burning,
recently adopted officially as the limit to distinguish the two types of
objects, is unlikely to play any specific role in star formation, so that such
a limit is of purely semantic nature and is not supported by a physical
justification.


title: Dark Matter Halos in a Secondary Infall Model

abstract:
  We calculate the density profiles of virialized halos in the case of
structure evolving hierarchically from a scale-free Gaussian delta-field having
a power spectrum $P(k)\propto k^n$ in a Omega=1 Universe; we suppose that the
initial density contrast profile around local maxima is given by the mean peak
profile introduced by Bardeen et al. (1986 hereafter BBKS). We show both that
the density profiles are not power-laws but have a logarithmic slope that
increases from the inner halo to its outer parts and for n \geq -1 are well
approximated by Navarro et al. (1995, 1996, 1997) profile and the radius a, at
which the slope alpha=-2, is a function of the mass of the halo and of the
spectral index n.


title:
Fornax compact object survey FCOS: On the nature of Ultra Compact Dwarf
  galaxies

abstract:
  The results of the Fornax Compact Object Survey (FCOS) are presented. The
FCOS aims at investigating the nature of the Ultra Compact Dwarf galaxies
(UCDs) recently discovered in the center of the Fornax cluster (Drinkwater et
al. 2000). 280 unresolved objects in the magnitude space covering UCDs and
bright globular clusters (18<V<21 mag) were observed spectroscopically. 54 new
Fornax members were discovered, plus five of the seven already known UCDs.
Their distribution in radial velocity, colour, magnitude and space was
investigated. It is found that bright compact objects (V<20 or M_V<-11.4 mag),
including the UCDs, have a higher mean velocity than faint compact objects
(V>20 mag) at 96% confidence. The mean velocity of the bright compact objects
is consistent with that of the dwarf galaxy population in Fornax, but
inconsistent with that of NGC 1399's globular cluster system at 93.5%
confidence. The compact objects follow a colour magnitude relation with a slope
very similar to that of normal dEs, but shifted about 0.2 mag redwards. The
magnitude distribution of compact objects shows a fluent transition between
UCDs and GCs with an overpopulation of 8 +/- 4 objects for V<20 mag with
respect to the extrapolation of NGC 1399's GC luminosity function. The spatial
distribution of bright compact objects is in comparison to the faint ones more
extended at 88% confidence. All our findings are consistent with the threshing
scenario (Bekki et al. 2003), suggesting that a substantial fraction of compact
Fornax members brighter than V~20 mag could be created by threshing dE,Ns.
Fainter than V~20 mag, the majority of the objects seem to be genuine GCs. Our
results are also consistent with merged stellar super-clusters (Fellhauer &
Kroupa 2002) as an alternative explanation for the bright compact objects.


title:
X-ray temperature distribution function of clusters in presence of large
  non-radial motions

abstract:
  We consider the non-radial motions, originating in the outskirts of clusters
of galaxies and we show how it may reduce the discrepancy between Cold Dark
Matter (CDM) predicted X-ray temperature distribution function of clusters of
galaxies and that really observed, so resolving the problem of the X-ray
clusters abundance over-production predicted by the CDM model. We construct the
X-ray temperature distribution function using Press-Schechter's (1974) theory
and Evrard's (1990) prescriptions for the mass-temperature relation, taking
also account of the non-radial motions originating from the gravitational
interaction of the quadrupole moment of the protocluster. Then, we compare our
X-ray temperature distribution function with the tidal field of the matter of
the neighboring protostructures. We find that the model produces a reasonable
cluster temperature distribution.


title: Multiperiodic RR Lyrae stars in the center of the Galaxy

abstract:
  This paper presents results of a fully automated search for multiperiodic RR
Lyrae stars in the center of the Galaxy. The search was carried out on OGLE-II
database created by means of image subtraction method. I found more than 2700
RR Lyrae stars with about 600 showing various kinds of multiperiodic behavior.
Previous OGLE-I database contained only about 200 RR Lyrae stars in the
Galactic Bulge, that is twelve times less than the current sample. There are
two most interesting outcomes for Bulge: very high percentage of Blazhko stars
and very low percentage of RRd stars. Blazhko effect was confirmed in about 25
percent of all RRab stars. This incidence rate is almost 2.5 times greater than
in the Large Magellanic Cloud. On the other hand I discovered only 3 RRd stars,
which implies that the incidence rate of this type of variables is much smaller
in Bulge than in the Magellanic Clouds.


title:
A Rotating Collapsar and Possible Interpretation of the LSD Neutrino
  Signal from SN 1987A

abstract:
  We consider an improved rotational mechanism of the explosion of a collapsing
supernova. We show that this mechanism leads to two-stage collapse with a phase
difference of \sim 5 h. Based on this model, we attempt a new interpretation of
the events in underground neutrino detectors on February 23, 1987, related to
the supernova SN 1987A.


title:
Green Bank Telescope Observations of the Eclipse of Pulsar "A" in the
  Double Pulsar Binary PSR J0737-3039

abstract:
  We report on the first Green Bank Telescope observations at 427, 820 and 1400
MHz of the newly discovered, highly inclined and relativistic double pulsar
binary. We focus on the brief eclipse of PSR J0737-3039A, the faster pulsar,
when it passes behind PSR J0737-3039B. We measure a frequency-averaged eclipse
duration of 26.6 +/- 0.6 s, or 0.00301 +/- 0.00008 in orbital phase. The
eclipse duration is found to be significantly dependent on radio frequency,
with eclipses longer at lower frequencies. Specifically, eclipse duration is
well fit by a linear function having slope (-4.52 +/- 0.03) x 10^{-7}
orbits/MHz. We also detect significant asymmetry in the eclipse. Eclipse
ingress takes 3.51 +/- 0.99 times longer than egress, independent of radio
frequency. Additionally, the eclipse lasts (40 +/- 7) x 10^{-5} in orbital
phase longer after conjunction, also independent of frequency. We detect
significant emission from the pulsar on short time scales during eclipse in
some orbits. We discuss these results in the context of a model in which the
eclipsing material is a shock-heated plasma layer within the slower PSR
J0737-3039B's light cylinder, where the relativistic pressure of the faster
pulsar's wind confines the magnetosphere of the slower pulsar.


title:
The Luminosity-Metallicity relation in the local universe from the 2dF
  Galaxy Redshift Survey

abstract:
  We investigate the Luminosity-Metallicity (L-Z) relation in the local
universe (z < 0.15) using spectra of 6387 star-forming galaxies extracted from
the 2dF Galaxy Redshift Survey. This sample is by far the largest to date used
to perform such a study. We distinguish star-forming galaxies from AGNs using
"standard" diagnostic diagrams to build a homogeneous sample of starburst
galaxies for the L-Z study. We propose new diagnostic diagrams using "blue"
emission lines ([OII]3727, [OIII]5007 and Hbeta) only to discriminate
starbursts from AGNs in intermediate-redshift (z > 0.3) galaxies.
Oxygen-to-hydrogen (O/H) abundance ratios are estimated using the "strong-line"
method, which relates the strength of bright emission lines (parameters R23 and
O32) to O/H. We confirm the existence of the luminosity-metallicity relation
over a large range of abundances (~ 2 dex) and luminosities (~ 9 magnitudes).
We find a linear relation between the gas-phase oxygen abundance and both the
"raw" and extinction-corrected absolute B-band magnitude with a rms of 0.27. A
similar relation, with nearly the same scatter, is found in the R band. This
relation is in good agreement with the one derived by Melbourne & Salzer (2002)
using the KISS data. However, our L-Z relation is much steeper than previous
determinations using samples of "normal" irregular and spiral galaxies. This
difference seems to be primarily due to the choice of the galaxy sample used to
investigate the L-Z relation rather than any systematic error affecting the O/H
determination. We anticipate that this luminosity-metallicity relation will be
used as the local "reference" for future studies of the evolution with cosmic
time of fundamental galaxy scaling relations. (Abridged version).


title: Multi-transition VLBA observations of circumstellar SiO masers

abstract:
  On this paper, we present simultaneous VLBA observations of the J=1-0 and
J=2-1 rotational lines in the v=1 and v=2 vibrationally excited states of SiO
(at 7 and 3 mm wavelengths). We have mapped these four maser lines in the
circumstellar envelopes of three AGB stars: IRC +10011, Chi Cyg and TX Cam. We
study the relative spatial distribution between these maser lines. In
particular, for the two v=1 transitions, we found that the J=1-0 and J=2-1
maser spot distributions are unalike, challenging all the current theoretical
pumping mechanisms for SiO masers (which predict quite similar distribution for
maser lines in the same vibrational excited state).


title: Dusty Starbursts and the Growth of Cosmic Structure

abstract:
  Dusty starbursts were more numerous around z~1 than today and appear to be
responsible for the majority of cosmic star formation over the Hubble time. We
suggest that they represent a common phase within galaxies in general which is
triggered by the growth of cosmic structure. We discuss the origin of the
luminosity of luminous infrared galaxies at z~1. Are these galaxies dominated
by star formation or nuclear activity ? What is triggering their strong
activity ? Is it triggered by external interactions or did it happen naturally
within isolated galaxies ? We present HST-ACS high resolution optical images of
luminous infrared galaxies at z~0.7 showing the evolution of the morphology of
these galaxies as a function of infrared luminosity, or star formation rate,
and discuss the effect of the environment on their activity.


title: Estimating the bispectrum of the Very Small Array data

abstract:
  We estimate the bispectrum of the Very Small Array data from the compact and
extended configuration observations released in December 2002, and compare our
results to those obtained from Gaussian simulations. There is a slight excess
of large bispectrum values for two individual fields, but this does not appear
when the fields are combined. Given our expected level of residual point
sources, we do not expect these to be the source of the discrepancy. Using the
compact configuration data, we put an upper limit of 5400 on the value of f_NL,
the non-linear coupling parameter, at 95 per cent confidence. We test our
bispectrum estimator using non-Gaussian simulations with a known bispectrum,
and recover the input values.


title: The Globular Cluster Systems of the Sculptor Group

abstract:
  We use CTIO 4-m Mosaic II images taken with the Washington $CM$ and Harris
$R$ filters to identify candidate globular clusters in the six major galaxies
of the Sculptor group: NGC 45, NGC 55, NGC 247, NGC 254, NGC 300, and NGC 7793.
  From follow-up spectroscopy with Hydra-CTIO, we find 19 new globular clusters
in NGC 55, NGC 247, NGC 253, and NGC 300, bringing the total number of known
Sculptor group globular clusters to 36. The newly discovered clusters have
spectroscopic ages consistent with those of old Milky Way globular clusters,
and the majority are metal-poor. Their luminosity function closely resembles
that of the Milky Way's globular clusters; their metallicity distribution is
somewhat more metal-rich, but this may be the result of our color selection of
candidates. The mean [$\alpha$/Fe] ratio in the clusters is $-0.2\pm0.3$, which
is lower than the Milky Way average. The specific frequencies $S_N$ are similar
to those of other late-type galaxies. However, if we calculate the specific
frequency using the $K$-band total magnitudes of the host galaxies, we find
values that are more than a factor of two higher. The kinematics of the
globular cluster systems are consistent with rotation with the \ion{H}{1} disk
in each of the four galaxies; however, only in NGC 253 is this result based on
more than seven objects. We suggest that the Sculptor group galaxies add to
evidence indicating that many of the first generation globular clusters formed
in disks, not halos.


title:
Probing the Magnetic Field Structure in Gamma-Ray Bursts through
  Dispersive Plasma Effects on the Afterglow Polarization

abstract:
  (Abr) The origin and structure of magnetic fields in Gamma-Ray Burst (GRB)
fireball plasmas are two of the most important open questions in all GRB
models. We show that the structure and strength of the magnetic field may be
constrained by radio and IR observations of the early afterglow, where plasma
effects on the polarization of propagating radiation are significant. We
calculate these propagation effects for cold and relativistic plasmas, and find
that in the presence of a uniform equipartition field the degree of linear
polarization is suppressed, and circular polarization prevails at low
frequencies, nu < 1-3 GHz, (2x10^11 Hz < nu < few x 10^14 Hz) in the forward
(reverse) shock. At higher frequencies linear polarization dominates. At the
frequency of the transition between circular and linear polarization, the net
level of polarization is minimal, ~10-20%. These features are nearly
independent of the circumburst density. The transition frequency is smaller by
a factor of ~10 when the uniform field is much weaker than equipartition. The
dependence of these results on viewing geometry, outflow collimation and
magnetic field orientation is discussed. When the configuration of the field is
entangled over length scales much smaller than the extent of the emitting
plasma, the aforementioned effects should not be observed and a linear
polarization at the few % level is expected. Polarimetric observations during
the early afterglow, and particularly of the reverse shock emission, may
therefore place strong constraints on the structure and strength of the
magnetic field within the fireball plasma.


title: Small-scale variations in the radiating surface of the GRB 011211 jet

abstract:
  We report the discovery of the afterglow of the X-ray rich, long-duration
gamma-ray burst GRB 011211 and present evidence for oscillatory behaviour in
its early optical light curve. The time-scale of the fluctuations, ~1 hour, is
much smaller than the time of the observations, ~12 hours from the onset of the
gamma-ray burst. The character and strength of the fluctuations are
unprecedented and are inconsistent with causally connected variations in the
emission of a symmetric, relativistic blast wave, i.e. flux variations which
are produced uniformly throughout the shell surface are ruled out. Therefore,
the wiggles are the result of spherically asymmetric density or energy
variations. Additionally, there is evidence for fluctuations in the X-ray
afterglow light curve. If real, the resulting difference in the observed time
of the peaks of the short-term variations at X-ray and optical frequencies,
would demonstrate that the energy content across the jet-emitting surface is
not uniform.


title: Statistical Challenges of Cosmic Microwave Background Analysis

abstract:
  The Cosmic Microwave Background (CMB) is an abundant source of cosmological
information. However, this information is encoded in non-trivial ways in a
signal that is difficult to observe. The resulting challenges in extracting
this information from CMB data sets have created a new frontier. In this talk I
will discuss the challenges of CMB data analysis. I review what cosmological
information is contained in the CMB data and the problem of extracting it. CMB
analyses can be divided into two types: ``canonical'' parameter extraction
which seeks to obtain the best possible estimates of cosmological parameters
within a pre-defined theory space and "hypothesis testing" which seeks to test
the assumption on which the canonical tests rest. Both of these activities are
fundamentally important. In addition to mining the CMB for cosmological
information cosmologists would like to strengthen the analysis with data from
other cosmologically interesting observations as well as physical constraints.
This gives an opportunity 1) to test the results from these separate probes for
concordance and 2) if concordance is established to sharpen the constraints on
theory space by combining the information from these separate sources.


title:
MAGIC: Exact Bayesian Covariance Estimation and Signal Reconstruction
  for Gaussian Random Fields

abstract:
  In this talk I describe MAGIC, an efficient approach to covariance estimation
and signal reconstruction for Gaussian random fields (MAGIC Allows Global
Inference of Covariance). It solves a long-standing problem in the field of
cosmic microwave background (CMB) data analysis but is in fact a general
technique that can be applied to noisy, contaminated and incomplete or censored
measurements of either spatial or temporal Gaussian random fields. In this talk
I will phrase the method in a way that emphasizes its general structure and
applicability but I comment on applications in the CMB context. The method
allows the exploration of the full non-Gaussian joint posterior density of the
signal and parameters in the covariance matrix (such as the power spectrum)
given the data. It generalizes the familiar Wiener filter in that it
automatically discovers signal correlations in the data as long as a noise
model is specified and priors encode what is known about potential
contaminants. The key methodological difference is that instead of attempting
to evaluate the likelihood (or posterior density) or its derivatives, this
method generates an asymptotically exact Monte Carlo sample from it. I present
example applications to power spectrum estimation and signal reconstruction
from measurements of the CMB. For these applications the method achieves
speed-ups of many orders of magnitude compared to likelihood maximization
techniques, while offering greater flexibility in modeling and a full
characterization of the uncertainty in the estimates.


title: Measuring neutrino masses with supernova neutrinos

abstract:
  A new method to study the effects of neutrino masses on a supernova neutrino
signal is proposed. The method relies exclusively on the analysis of the full
statistics of neutrino events, it is independent of astrophysical assumptions,
and does not require the observation of any additional phenomenon to trace
possible delays in the neutrino arrival times. A statistics of several
thousands of events as could be collected by SuperKamiokande, would allow to
explore a neutrino mass range somewhat below 1eV.


title: Cosmology and the Stellar Halo

abstract:
  If the favored hierarchical cosmological model is correct, then the Milky Way
system should have accreted and subsequently tidally destroyed ~100 low-mass
galaxies in the past ~12 Gyr. We model this process using a hybrid
semi-analytic plus N-body approach and show that the disrupted systems lead
naturally to stellar halos with masses and density profiles much like the
stellar halo of our own Galaxy. We present predictions for the properties of
stellar halos and show that ours is likely dominated by substructure beyond
\~50kpc and more spatially smooth within that radius. The average stellar halo
density profile is expected to drop off with radius more quickly than that of
the dark matter because the stellar halo is formed from the most tightly bound
material in infalling systems, while the majority of the accreted dark matter
is stripped and deposited at larger radii. We argue that stars associated with
the inner halo should be quite different chemically from stars in surviving
satellites and also different from stars in the outer halo or those liberated
in recent disruption events. We discuss how deep halo surveys and chemical
probes may be useful tools for uncovering evidence of accretion. Searches of
this kind offer a direct test of whether cosmology is indeed hierarchical on
small scales.


title: Optical variability of PKS 0736+017

abstract:
  We present BVR photometric observations of the blazar PKS 0736+017. These
observations were carried out with three telescopes in Mexico and two in Spain
between December 1998 and April 2003. PKS 0736+017 shows remarkable variation
at different timescales and amplitudes. Maximum brightness was detected on
December 19, 2001 (B=14.90+/-0.01, V=14.34+/-0.01, and R=13.79+/-0.01). A
peculiar tendency to redden with increased brightness was detected throughout
our observations. Moreover, in one season a good correlation between flux level
and spectral slope is shown. This "anomalous" behaviour cannot be described by
common flare models of blazars. The flux vs. spectral slope correlation
observed in this and other blazars is worth further study.


title: A relativistic helical jet in the gamma-ray AGN 1156+295

abstract:
  We present the results of a number of high resolution radio observations of
the AGN 1156+295. These include multi-epoch and multi-frequency VLBI, VSOP,
MERLIN and VLA observations made over a period of 50 months. The 5 GHz MERLIN
images trace a straight jet extending to 2 arcsec at P.A. -18 degrees. Extended
low brightness emission was detected in the MERLIN observation at 1.6 GHz and
the VLA observation at 8.5 GHz with a bend of about 90 degrees at the end of
the 2 arcsecond jet. A region of similar diffuse emission is also seen about 2
arcseconds south of the radio core. The VLBI images of the blazar reveal a
core-jet structure with an oscillating jet on a milli-arcsecond (mas) scale
which aligns with the arcsecond jet at a distance of several tens of
milli-arcseconds from the core. This probably indicates that the orientation of
the jet structure is close to the line of sight, with the northern jet being
relativistically beamed toward us. In this scenario the diffuse emission to the
north and south is not beamed and appears symmetrical. For the northern jet at
the mas scale, proper motions of 13.7 +/-3.5, 10.6 +/- 2.8, and 11.8 +/- 2.8 c
are measured in three distinct components of the jet (q_0=0.5, H_0=65 km /s
/Mpc are used through out this paper). Highly polarised emission is detected on
VLBI scales in the region in which the jet bends sharply to the north-west. The
spectral index distribution of the source shows that the strongest compact
component has a flat spectrum, and the extended jet has a steep spectrum. A
helical trajectory along the surface of a cone was proposed based on the
conservation laws for kinetic energy and momentum to explain the observed
phenomena, which is in a good agreement with the observed results on scales of
1 mas to 1 arcsec.


title:
A Realistic Model for Spatial and Mass Distributions of Dark Halo
  Substructures: An Analytic Approach

abstract:
  We construct a realistic model for the dark halo substructures, and derive
analytically their spatial, mass, and velocity distributions. Basically, our
model is a modification of the Press-Schechter theory to account for the
dominant dynamical processes that mark the evolution of dark halo substructures
such as the tidal stripping and dynamical friction. Our analytic model
successfully reproduces all the well known behaviors of the substructure
distributions that have been found in recent numerical simulations: the weak
dependence of the mass distributions on the host halo mass; the anti-bias of
the spatial distribution relative to the dark matter particle components; the
nearly power-law shapes of the mass and velocity distributions. We compare our
analytic results with recent high-resolution N-body simulation data and find
that they are in excellent agreement with each other.


title: Primary Particle Type of the Most Energetic Fly's Eye Air Shower

abstract:
  The longitudinal profile of the most energetic cosmic-ray air shower measured
so far, the event recorded by the Fly's Eye detector with a reconstructed
primary energy of about 320 EeV, is compared to simulated shower profiles. The
calculations are performed with the CORSIKA code and include primary photons
and different hadron primaries. For primary photons, preshower formation in the
geomagnetic field is additionally treated in detail. For primary hadrons, the
hadronic interaction models QGSJET01 and SIBYLL2.1 have been employed. The
predicted longitudinal profiles are compared to the observation. A method for
testing the hypothesis of a specific primary particle type against the measured
profile is described which naturally takes shower fluctuations into account.
The Fly's Eye event is compatible with any assumption of a hadron primary
between proton and iron nuclei in both interaction models, although differences
between QGSJET01 and SIBYLL2.1 in the predicted profiles of lighter nuclei
exist. The primary photon profiles differ from the data on a level of ~1.5
sigma. Although not favoured by the observation, the primary photon hypothesis
can not be rejected for this particular event.


title:
Modelling the spectral energy distribution of galaxies. III. Attenuation
  of stellar light in spiral galaxies

abstract:
  We present new calculations of the attenuation of stellar light from spiral
galaxies using geometries for stars and dust which can reproduce the entire
spectral energy distribution from the UV to the FIR/submm and can also account
for the surface brightness distribution in both the optical/NIR and FIR/submm.
The calculations are based on the model of Popescu et al. (2000), which
incorporates a dustless stellar bulge, a disk of old stars with associated
diffuse dust, a thin disk of young stars with associated diffuse dust, and a
clumpy dust component associated with star-forming regions in the thin disk.
The attenuations, which incorporate the effects of multiple anisotropic
scattering, are derived separately for each stellar component, and presented in
the form of easily accessible polynomial fits as a function of inclination, for
a grid in optical depth and wavelength. The wavelength range considered is
between 912 AA and 2.2 micron, sampled such that attenuation can be
conveniently calculated both for the standard optical bands and for the bands
covered by GALEX. The attenuation characteristics of the individual stellar
components show marked differences between each other. A general formula is
given for the calculation of composite attenuation, valid for any combination
of the bulge-to-disk ratio and amount of clumpiness. As an example, we show how
the optical depth derived from the variation of attenuation with inclination
depends on the bulge-to-disk ratio. Finally, a recipe is given for a
self-consistent determination of the optical depth from the Halpha/Hbeta line
ratio.


title: Variations of the Fine Structure Constant in Space and Time

abstract:
  This thesis describes a detailed investigation of the effects of matter
inhomogeneities on the cosmological evolution of the fine structure constant
using the Bekenstein-Sandvik-Barrow-Magueijo (BSBM) theory. We briefly review
the observational and theoretical motivations to this work, together with the
standard cosmological model. We start by analysing the phase space of the
system of equations that describes a time-varying fine structure constant, in a
homogeneous and isotropic background universe. We classify all the possible
behaviours of the fine structure constant in ever-expanding universes and find
exact solutions for it. Using a gauge-invariant formalism, we derive and solve
the linearly perturbed Einstein cosmological equations for the BSBM theory. We
calculate the time evolution of inhomogeneous perturbations of the fine
structure constant on small and large scales with respect to the Hubble radius.
We also investigate, in the non-linear regime of the large scale structure
formation, the space-time evolution of the fine structure constant, inside
evolving spherical overdensities. The dependence on the dark-energy equation of
state is also analysed. Finally, we analyse the effects of the coupling of the
field (that drives the variations in the fine structure constant) to the matter
fields, on the space and time evolution of the fine structure constant.


title: Anisotropies in Ultrahigh Energy Cosmic Rays

abstract:
  The present status of anisotropy studies for the highest energy cosmic rays
is presented including the first full sky survey. Directions and prospects for
the future are also discussed in light of new statistical methods and the last
quantities of data expected in the near future from the Pierre Auger
Observatory.


title:
The Circumstellar Environments of High-Mass Protostellar Objects I:
  Submillimetre Continuum Emission

abstract:
  We present maps of the 850 micron and 450 micron continuum emission seen
towards a sample of 68 high-mass protostellar candidates with luminosities
ranging from 10^2.5 to 10^5 solar luminosity. Most of these candidate high-mass
stars are in the earliest stages of evolution, and have not yet developed an
ultra-compact HII region. We observe a variety of continuum emission
morphologies, from compact symmetric sources through to multiple cores embedded
in long filaments of emission. We find on average there is a 65% probability of
an IRAS point-source having a companion detection at submillimetre wavelengths.
The ratio of integrated flux to peak flux for our detections shows no strong
dependence on distance, suggesting the emission we have observed is primarily
from scale-free envelopes with power-law density structures. Assuming a near
kinematic distance projection, the clumps we detect vary in mass from ~1 to
over 1000 solar mass, with a mean clump mass of 330 solar mass, column density
of 9x10^23 cm^-2 and diameter of ~0.6 pc. The high luminosity and low mass of
the smallest clumps suggests they are accompanied by a minimal number of
stellar companions, while the most massive clumps may be examples of young
protogroups and protoclusters. We measure the spectral index of the dust
emission (alpha) and the spectral index of the dust grain opacity (beta)
towards each object, finding clumps with morphologies suggestive of strong
temperature gradients, and of grain growth in their dense inner regions. We
find a mean value for beta of 0.9, significantly smaller than observed towards
UCHII regions.


title:
Neutrino Processes in Strong Magnetic Fields and Implications for
  Supernova Dynamics

abstract:
  The processes of neutrino (antineutrino) absorption and electron (positron)
capture on nucleons provide the dominant mechanisms for heating and cooling the
material between the protoneutron star and the stalled shock in a core-collapse
supernova. Observations suggest that some neutron stars are born with magnetic
fields of at least 10^15 G while theoretical considerations give an upper limit
of 10^18 G for the protoneutron star magnetic fields. We calculate the rates
for the above neutrino processes in strong magnetic fields of 10^16 G. We find
that the main effect of such magnetic fields is to change the equations of
state through the phase space of electron and positron, which differs from the
classical case due to quantization of the motion of electron and positron
perpendicular to the magnetic field. As a result, the cooling rate can be
greatly reduced by magnetic fields of 10^16 G for typical conditions below the
stalled shock and a nonuniform protoneutron star magnetic field (e.g., a dipole
field) can introduce a large angular dependence of the cooling rate. In
addition, strong magnetic fields always lead to an angle-dependent heating rate
by polarizing the spin of nucleons. The implications of our results for the
neutrino-driven supernova mechanism are discussed.


title: On the origin of H2CO abundance enhancements in low-mass protostars

abstract:
  High angular resolution H2CO 218 GHz line observations have been carried out
toward the low-mass protostars IRAS 16293-2422 and L1448-C using the Owens
Valley Millimeter Array at ~2" resolution. Simultaneous 1.37 mm continuum data
reveal extended emission which is compared with that predicted by model
envelopes constrained from single-dish data. For L1448-C the model density
structure works well down to the 400 AU scale to which the interferometer is
sensitive. For IRAS 16293-2422, a known proto-binary object, the interferometer
observations indicate that the binary has cleared much of the material in the
inner part of the envelope, out to the binary separation of ~800 AU. The
morphology and velocity structure of the H2CO array data have been used to
investigate whether the abundance enhancements inferred from single-dish
modelling are due to thermal evaporation of ices or due to liberation of the
ice mantles by shocks in the inner envelope. A scenario in which the H2CO
abundance drops in the cold dense part of the envelope where CO is frozen out
but is undepleted in the outermost region provides good fits to the single-dish
and interferometer data on short baselines for both sources. Emission on the
longer baselines is best reproduced if the H2CO abundance is increased by about
an order of magnitude from ~1E-10 to ~1E-9 in the inner parts of the envelope
due to thermal evaporation when the temperature exceeds ~50K. Other scenarios,
including weak outflow-envelope interactions and photon heating of the
envelope, are discussed and predictions for future generation interferometers
are presented, illustrating their potential in distinguishing these competing
scenarios.


title: Spectrophotometry of galaxies in the Virgo cluster.II: The data

abstract:
  Drift-scan mode (3600-6800 A) spectra with 500<R<1000 resolution are
presented for 333 galaxies members to nearby clusters, covering the whole
Hubble sequence. The majority (225) were obtained for galaxies in the Virgo
cluster where a completeness of 36%, if all Hubble types are considered, and of
51%, restricting to late-types, was reached at m_p<=16. Our data can be
therefore considered representative of the integrated spectral properties of
giant and dwarf galaxies in this cluster. Intensities and equivalent widths
(EWs) are derived for the principal lines, both in emission and in absorption.
Deblending of the underlying absorption from emission was achieved in most
cases.


title:
A General Relativistic Model of Light Propagation in the Gravitational
  Field of the Solar System: the Static Case

abstract:
  We develop here a new approach for the relativistic modeling of the photons
moving into a quasi-Minkowskian space-time, where the metric is generated by an
arbitrary n-body distribution within an isolated Solar System. Our model is
built on the prescriptions of the theory of General Relativity and leaves the
choices of the metric, as well as that of the motion of the observer,
arbitrary. Adopting a quasi-Minkowskian expression of the metric accurate to
order (v/c)^2, a thorough numerical test campaign is conducted to verify
correctness and reliability of the model equations. The test results show that
the model behaves according to predictions. Specifically, comparisons to true
(simulated) data demonstrate that stellar distances are reconstructed up to the
specified level of accuracy. Although the (v/c)^2 approximation is not always
sufficient for its application to future astrometric experiments, which require
modeling to (v/c)^3, this work serves also as a natural test-ground for the
higher order model, whose formulation is now close to completion, and will be
presented in a forthcoming paper.


title:
Infrared and visual lunar occultations measurements of stellar diameters
  and new binary stars detections at the Calar Alto 1.5m telescope

abstract:
  We present a program of routine lunar occultations, at optical and near-IR
wavelengths, recently started at the 1.5m Spanish telescope at the Calar Alto
Observatory. Both a CCD and an infrared array detector are used. The program is
aimed mainly at the detection and investigation of binary systems, although
results in other areas of stellar research are also anticipated.
  Occultations are reported for a total of 40 stars. Among these, SAO 164567,
SAO 78258 and AG+24 788 have been discovered to be binaries, with projected
separations as small as 0.006". Furthermore, binarity is suspected in the case
of SAO 78119 and SAO 79251. Additionally, the angular diameter of the late-type
giant 30 Psc and of the infrared star V349 Gem have been accurately measured,
this latter for the first time.
  We finally evaluate the instrumentation performance in terms of limiting
magnitude and angular resolution, and discuss applications to larger
telescopes.


title: High Resolution X-ray Spectroscopy of the Fe K complex in IC 4329A

abstract:
  We report the detection of complex Fe K line emission from a Chandra High
Energy Transmission Grating Spectrometer observation of the Seyfert 1 galaxy IC
4329A. The line emission is double-peaked, one peak centered at ~6.3 keV, and
the other at ~6.9 keV in the source rest frame. When modeled by Gaussians, the
lower energy peak is resolved by the HEG at >99% confidence, whilst the higher
energy peak is resolved at only <90% confidence. The best-fitting widths are
\~21,000km/s and ~4000km/s FWHM for the ~6.3 keV and ~6.9 keV peaks
respectively. If the peaks correspond to two distinct emission lines, then the
peak energies are redshifted with respect to the expected line energies of Fe I
Ka and Fe XXVI Lya by at least 650 km/s and 950 km/s respectively.
Alternatively, the Fe K line profile may be due to a single line from a
relativistic accretion disk. In that case the inclination angle of the disk is
required to be 24^{+9}_{-1} degrees, the outer radius constrained to several
tens of gravitational radii, and the radial line emissivity flatter than
r^{-0.7}. Another possibility is that both peaks are due to distinct lines but
each one relativistically broadened by a disk. In that case the lower energy
peak could correspond to emission from Fe in a low ionization state, and the
high-energy peak to Fe XXVI Lya emission. Then, the inclination angle is even
less, restricted to a few degrees. However, the radial emissivity law is
allowed to be steeper (~r^{-2.5}) and the outer radius does not have to be
fine-tuned. Yet another scenario is that the lower energy peak originates in a
disk but the higher energy peak originates in more distant matter.


title: Differential rotation of cool active stars

abstract:
  The surface differential rotation of active solar-type stars can be
investigated by means of Doppler and Zeeman-Doppler Imaging, both techniques
enabling one to estimate the short-term temporal evolution of photospheric
structures (cools spots or magnetic regions). After describing the main
modeling tools recently developed to guarantee a precise analysis of
differential rotation in this framework, we detail the main results obtained
for a small number of active G and K fast rotating stars. We evoke in
particular some preliminary trends that can be derived from this sample,
bearing the promise that major advances in this field will be achieved with the
new generation of spectropolarimeters (ESPaDOnS/CFHT, NARVAL/TBL).


title:
Spectro-photometric and Weak Lensing Survey of a Supercluster and
  Typical Field Region -- I. Spectroscopic Redshift Measurements

abstract:
  We present results from a spectroscopic study of ~4000 galaxies in a 6.2
square degree field in the direction of the Aquarius supercluster and a smaller
typical field region in Cetus, down to R<19.5. Galaxy redshifts were measured
using the Two Degree Field system on the Anglo-Australian Telescope, and form
part of our wider efforts to conduct a spectro-photometric and weak
gravitational lensing study of these regions. At the magnitude limit of the
survey, we are capable of probing L_* galaxies out to z~0.4. We construct
median spectra as a function of various survey parameters as a diagnostic of
the quality of the sample. We use the redshift data to identify galaxy clusters
and groups within the survey volume. In the Aquarius region, we find a total of
48 clusters and groups, of which 26 are previously unknown systems, and in
Cetus we find 14 clusters and groups, of which 12 are new. We estimate centroid
redshifts and velocity dispersions for all these systems. In the Aquarius
region, we see a superposition of two strong superclusters at z=0.08 and
z=0.11, which both have estimated masses and overdensities similar to the
Corona Borealis supercluster.


title:
Collisional depolarization and transfer rates of spectral lines by
  atomic hydrogen. IV: application to ionised atoms

abstract:
  The semi-classical theory of collisional depolarization of spectral lines of
neutral atoms by atomic hydrogen (Derouich et al. 2003a; Derouich et al. 2003b;
Derouich et al. 2004 and references therein) is extended to spectral lines of
singly ionised atoms. In this paper we apply our general method to the
particular cases of the 3d $^2D$ and $4p$ $^2P$ states of the CaII ion and to
the $5p$ $^2P$ state of the SrII ion. Analytical expressions of all rates as a
function of local temperature are given.
  Our results for the CaII ion are compared to recent quantum chemistry
calculations. A discussion of our results is presented.


title:
The dust-enshrouded microquasar candidate AX J1639.0-4642 = IGR
  J16393-4643

abstract:
  We present a multiwavelength study of the field containing the unidentified
X-ray source AX J1639.0-4642, discovered with the ASCA observatory and recently
detected with the IBIS telescope, onboard the INTEGRAL satellite, dubbed IGR
J16393-4643. The huge hydrogen column density towards the source, the hard
spectral index in the 0.7-10 keV band and its flux variability suggest that the
source is a High Mass X-ray Binary (HMXB) enshrouded by dust. Our search
reveals the presence of a non-thermal radio counterpart within the X-ray error
box. After a study of the broadband emission from X-rays to the radio domain,
we propose that AX J1639.0-4642 is a dust-enshrouded Microquasar (MQ)
candidate. In addition, the X-ray source is well within the 95% location
contour of the unidentified gamma-ray source 3EG J1639-4702. The main
properties of AX J1639.0-4642/3EG J1639-4702 are consistent with those of two
other MQs previously proposed to display high-energy gamma-ray emission.


title: Rectangular-Mask Coronagraphs for High-Contrast Imaging

abstract:
  We present yet another new family of masks for high-contrast imaging as
required for the to-be-built terrestrial planet finder space telescope. The
``best'' design involves a square entrance pupil having a 4-vane spider, a
square image-plane mask containing a plus-sign shaped occulter to block the
starlight inside 0.6 lambda/D, and a Lyot-plane mask consisting of a
rectangular array of rectangular opennings. Using Fraunhofer analysis, we show
that the optical system can image a planet 10^{-10} times as bright as an
on-axis star in four rectangular regions given by {(xi,zeta): 1.4 < | xi | <
20, 1.4 < | zeta | < 20}.
  Since the design involves an image plane mask, pointing error is an issue. We
show that the design can tolerate pointing errors of about 0.05 lambda/D.
  The inclusion of a 4-vane spider in the entrance pupil provides the
possibility to build a mirror-only on-axis system thereby greatly reducing the
negative effects of polarization.
  Each of the masks can be realized as two masks consisting of stripes of
opaque material with the stripes oriented at right angles to each other. We
call these striped masks barcode masks. We show that it is sufficient for the
barcode masks by themselves to provide 10^{-5} contrast. This then guarantees
that the full system will provide the required 10^{-10} contrast.


title: Morphological Type Dependence in the Tully-Fisher Relationship

abstract:
  The Tully-Fisher relationship is subject to morphological type dependence
such that galaxies of morphology similar to ScI galaxies and Seyfert galaxies
are more luminous at a given rotational velocity than galaxies of other
morphological classification. This effect is most prevalent in the B-band. It
is shown that the type effect is not simply an artifact of the calibrator
sample, but is also present in cluster samples. The type effect is corrected by
creating type dependent Tully-Fisher relations for ScI group galaxies and
Sb/ScIII group galaxies. It is shown that with single calibrations, the
distances to ScI group galaxies are systematically underestimated while the
distances to Sb/ScIII group galaxies are systematically overestimated.
Tully-Fisher slope and scatter is also considered in the context of Type
Dependent Tully-Fisher relations. It is concluded that the use of type
dependent Tully-Fisher relations provide significant improvement in the
distances to individual galaxies and refined distances to clusters of galaxies.


title:
Redshift Accuracy Requirements for Future Supernova and Number Count
  Surveys

abstract:
  We investigate the required redshift accuracy of type Ia supernova and
cluster number-count surveys in order for the redshift uncertainties not to
contribute appreciably to the dark energy parameter error budget. For the SNAP
supernova experiment, we find that, without the assistance of ground-based
measurements, individual supernova redshifts would need to be determined to
about 0.002 or better, which is a challenging but feasible requirement for a
low-resolution spectrograph. However, we find that accurate redshifts for z<0.1
supernovae, obtained with ground-based experiments, are sufficient to immunize
the results against even relatively large redshift errors at high z. For the
future cluster number-count surveys such as the South Pole Telescope, Planck or
DUET, we find that the purely statistical error in photometric redshift is less
important, and that the irreducible, systematic bias in redshift drives the
requirements. The redshift bias will have to be kept below 0.001-0.005 per
redshift bin (which is determined by the filter set), depending on the sky
coverage and details of the definition of the minimal mass of the survey.
Furthermore, we find that X-ray surveys have a more stringent required redshift
accuracy than Sunyaev-Zeldovich (SZ) effect surveys since they use a shorter
lever arm in redshift; conversely, SZ surveys benefit from their high redshift
reach only so long as some redshift information is available for distant (z>1)
clusters.


title:
The s-process in metal-poor stars: Abundances for 22 neutron-capture
  elements in CS 31062-050

abstract:
  The CH star CS 31062-050 ([Fe/H]=-2.42) is one of the most useful stars yet
discovered for evaluating the s-process in metal-poor stars. It is very
abundant in heavy elements (e.g., [La/Fe]=2.2), and its relatively cool
temperature and low gravity mean that there are many lines of interesting
elements present in the spectrum. We measured the abundances of 22 elements
with Z>29, including the rarely measured Lu and Pd. We derive an upper limit on
the Th abundance as well. The abundances in CS 31062-050 show a similar pattern
to many other metal-poor CH stars: high [Pb/Fe] and [Pb/La] ratios, low [Y/La]
ratios and high [Eu/La] values compared to the solar system s-process. However,
the Th limit, with additional assumptions, is not consistent with the idea that
the excess Eu in CS 31062-050 is contributed by the r-process. In addition, the
observed [Eu/Tb] cannot be explained by any ratio of solar-system s-process and
r-process abundances. We therefore argue that the abundance pattern in CS
31062-050 is most likely the result of the s-process, and we discuss possible
modifications that could explain the non-solar-system pattern observed.


title: Cluster Lensing of the CMB

abstract:
  We investigate what the lensing information contained in high resolution, low
noise CMB temperature maps can teach us about cluster mass profiles. We create
lensing fields and Sunyaev-Zel'dovich effect maps from N-body simulations and
apply them to primary CMB anisotropies modeled as a Gaussian random field. We
examine the success of several techniques of cluster mass reconstruction using
CMB lensing information, and make an estimate of the observational requirements
necessary to achieve a satisfactory result.


title:
Line-broadening in gravitational radiation from gamma-ray
  burst-supernovae

abstract:
  Core-collapse in massive stars is believed to produce a rapidly spinning
black hole surrounded by a compact disk or torus. This forms an energetic
MeV-nucleus inside a remnant He-core, powered by black hole-spin energy. The
output produces a GRB-supernova, while most of the energy released is in
gravitational radiation. The intrinsic gravitational-wave spectrum is
determined by multipole mass-moments in the torus. Quadrupole gravitational
radiation is radiated at about twice the Keplerian frequency of the torus,
which is non-axisymmetric when sufficiently slender, representing a ``{\em
black hole-blob}" binary system or a "{\em blob-blob}" binary bound to the
central black hole. We here discuss line-broadening in the observed spectrum
due to Lense-Thirring precession, which modulates the orientation of the torus
to the line-of-sight. This spectral feature is long-lived, due to weak damping
of precessional motion. These events are believed to occur perhaps once per
year within a distance of 100Mpc, which provides a candidate source for
Advanced LIGO.


title:
Stochastic Analysis of Subcritical Amplification of Magnetic Energy in a
  Turbulent Dynamo

abstract:
  We present and analyze a simplified stochastic $\alpha \Omega -$dynamo model
which is designed to assess the influence of additive and multiplicative
noises, non-normality of dynamo equation, and nonlinearity of the $\alpha -$%
effect and turbulent diffusivity, on the generation of a large-scale magnetic
field in the subcritical case. Our model incorporates random fluctuations in
the $\alpha -$parameter and additive noise arising from the small-scale
fluctuations of magnetic and turbulent velocity fields. We show that the noise
effects along with non-normality can lead to the stochastic amplification of
the magnetic field even in the subcritical case. The criteria for the
stochastic instability during the early kinematic stage are established and the
critical value for the intensity of multiplicative noise due to $\alpha
-$fluctuations is found. We obtain numerical solutions of non-linear stochastic
differential equations and find the series of phase transitions induced by
random fluctuations in the $\alpha -$parameter.


title: Neutrino Detection With CLEAN

abstract:
  This article describes CLEAN, an approach to the detection of low-energy
solar neutrinos and neutrinos released from supernovae. The CLEAN concept is
based on the detection of elastic scattering events (neutrino-electron
scattering and neutrino-nuclear scattering) in liquified noble gases such as
liquid helium, liquid neon, and liquid xenon, all of which scintillate brightly
in the ultraviolet. Key to the CLEAN technique is the use of a thin film of
wavelength-shifting fluor to convert the ultraviolet scintillation light to the
visible. This allows the same liquid to be used as both a passive shielding
medium and an active self-shielding detector, allowing lower intrinsic
radioactive backgrounds at low energies. Liquid neon is a particularly
promising medium for CLEAN. Because liquid neon has a high scintillation yield,
has no long-lived radioactive isotopes, and can be easily purified by use of
cold traps, it is an ideal medium for the detection of rare nuclear events. In
addition, neon is inexpensive, dense, and transparent to its own scintillation
light, making it practical for use in a large self-shielding apparatus. Monte
Carlo simulations of gamma ray backgrounds have been performed assuming liquid
neon as both shielding and detection medium. Gamma ray events occur with high
probability in the outer parts of the detector. In contrast, neutrino
scattering events occur uniformly throughout the detector. We discriminate
background gamma ray events from events of interest based on a spatial Maximum
Likelihood method estimate of event location. Background estimates for CLEAN
are presented, as well as an evaluation of the sensitivity of the detector for
$p-p$ neutrinos. Given these simulations, the physics potential of the CLEAN
approach is evaluated.


title: Beating Lensing Cosmic Variance with Galaxy Tomography

abstract:
  I discuss the use of cross correlations between galaxies with distance
information and projected weak lensing dark matter maps to obtain a fully three
dimensional dark matter map and power spectrum. On large scales l<100 one
expects the galaxies to be biased, but not stochastic. I show that this allows
a simultaneous solution of the full 3-D evolving galaxy bias and the dark
matter power spectrum simultaneously. Within the photo-z information of the CFH
lensing legacy survey, this allows a threefold reduction of statistical error,
while a cross correlation with CLAR or other deep spectroscopic surveys allows
a tenfold improvement in dark matter power accuracy on linear scales. This
makes lensing surveys more sensitive to the cosmic equation of state and the
neutrino masses.


title:
Simulation of a Combined SZE and Weak Lensing Cluster Survey for AMiBA
  Experiment

abstract:
  We present simulations of interferometric Sunyaev-Zel'dovich effect (SZE) and
optical weak lenisng observations for the forthcoming AMiBA experiment, aiming
at searching for high-redshift clusters of galaxies. On the basis of simulated
sky maps, we have derived theoretical halo number counts and redshift
distributions of selected halo samples for an AMiBA SZE survey and a weak
lensing follow-up survey. By utilizing the conditional number counts of weak
lensing halos with the faint SZE detection, we show that a combined SZE and
weak lensing survey can gain an additional fainter halo sample at a given false
positive rate, which cannot be obtained from either survey alone.


title:
H II emission line region in LEDA 212995, a small neighboring galaxy of
  Mrk 1040

abstract:
  We present here new spectroscopic observations of Mrk 1040 and LEDA 212995
(Mrk 1040 companion) obtained with the Isaac
  Newton Telescope (INT). The intensity ratios and widths for the narrow
emission lines found in LEDA 212995 are typical of H II regions. The red-shift
(0.0169$\pm$0.00015) of the object derived from these emission lines is very
close to the red-shift of Mrk 1040
  (z=0.01665). The weak narrow and broad absorption lines were detected in the
H$\alpha$ wavelength band of LEDA 212995 spectra. These absorptions indicate
that the companion might be at least partly obscured by Mrk 1040. Using this
and previous observations we discuss the possible physical relationship between
these two galaxies.


title: OH Absorption in the Line of Sight Towards Sagittarius B2

abstract:
  The giant molecular cloud complex, Sgr B2, was observed with the ISO Long
Wavelength Spectrometer over the range 47-197 microns. The ground state
rotational transitions of OH lie in the survey range and we have analysed
results from the 16OH, 17OH and 18OH isotopomers. Absorption in these lines due
to clouds along the line of sight towards Sgr B2 has allowed us to compare the
isotopomer abundance at different galactocentric radii. This is an excellent
test of previous results for the isotope ratios which were measured at radio
wavelengths and generally required a double ratio with 12C/13C.


title:
The importance of discovering a 3:2 twin-peak QPO in a ULX or how to
  solve the puzzle of intermediate mass black holes

abstract:
  Recently, twin-peak QPOs have been observed in a 3:2 ratio for three Galactic
black-hole microquasars with frequencies that have been shown to scale as 1/M,
as expected for general relativisitic motion near a black hole. It may be
possible to extend this result to distinguish between the following two
disparate models that have been proposed for the puzzling ultraluminous X-ray
sources (ULXs): (1) an intermediate-mass black hole M ~1000 solar mass)
radiating very near the Eddington limit and (2) a conventional black hole (M ~
10 solar mass) accreting at a highly super-Eddington rate with its emission
beamed along the rotation axis. We suggest that it may be possible to
distinguish between these models by detecting the counterpart of a Galactic
twin-peak QPO in a ULX: the expected frequency for the intermediate-mass black
hole model is only about 1 Hz, whereas, for the conventional black hole model
the expected frequency would be the ~100 Hz value observed for the Galactic
microquasars.


title: High-frequency QPOs as a problem in physics: non-linear resonance

abstract:
  The presence of a kHz frequency in LMXBs has been expected from scaling laws,
by analogy with the QPO phenomenon in HMXB X-ray pulsars. Interpretation of the
two kHz frequencies, observed in accreting neutron stars, in terms of
non-linear resonance in strong-field gravity led to the prediction of twin QPOs
in black hole systems, in a definite frequency ratio (such as 2/3). The imprint
of a subharmonic of the 401 Hz rotation rate in the frequencies of the QPOs
detected in the accreting millisecond pulsar is at once a signature of
non-linear resonance and of coupling between accretion disk modes and the
neutron star spin.


title: Methanol: a diagnostic tool for high-mass star-forming regions

abstract:
  We here present an innovative technique to handle the problem of deriving
physical parameters from observed multi-line spectra of methanol, based on the
simultaneous fit of all the lines with a synthetic spectrum computed under the
Large Velocity Gradient approximation; the best physical parameters are found
using numerical methods.


title: UYSO 1 - An Extremely Young Massive Stellar Object

abstract:
  In the course of a comprehensive mm/submm survey of massive star-forming
regions, a particularly interesting object has been found in the surroundings
of the bright FIR source IRAS 07029-1215, in a distance of 1 kpc. The object --
named UYSO 1 (Unidentified Young Stellar Object 1) -- is cold (T=40 K), it has
a massive envelope, and it is associated with an energetic molecular outflow.
No infrared point source has been detected at its position for wavelengths
below 20 micron. Therefore, it is a very good candidate for a member of the
long searched for group of massive protostars.


title:
Disappearance of N2H+ from the Gas Phase in the Class 0 Protostar IRAM
  04191

abstract:
  We present a high-resolution spectroscopic study of the envelope of the young
Class 0 protostar IRAM 04191+1522 in Taurus. N2H+(1-0) observations with the
Plateau de Bure Interferometer and the IRAM 30m telescope demonstrate that the
molecular ion N2H+ disappears from the gas phase in the inner envelope (r <
1600 AU, n(H2) > 4-7 * 1e5 cm-3). This may result from N2 depletion on polar
ice mantles and enhanced grain chemistry.


title: Line-of-sight distribution of water towards the SgrB2 complex

abstract:
  Here we report the detection, with the Caltech Submillimeter Observatory, of
the 894-GHz HDO(111-000) transition, observed in absorption against the
background continuum emission of the SgrB2 cores M and N. Radiative transfer
modeling of this feature, together with the published data set of mm and submm
HDO and H2O-18 transitions, suggests that ground-state absorption features from
deuterated and non-deuterated water trace different gas components along the
line of sight. In particular, while the HDO line seems to be produced by the
large column densities of gas located in the SgrB2 warm envelope, the H2O-18
ground-state transition detected by SWAS and KAO at 548 GHz (Neufeld et al.
2000; Zmuidzinas et al. 1995) is instead a product of the hot, diffuse, thin
gas layer lying in the foreground of the SgrB2 complex.


title: A Masing Molecular Cloud in the Central Parsecs of Mrk348

abstract:
  We report new observations of the H_2O megamaser in the Seyfert 2 galaxy
Mrk348. The line is redshifted by about 130 km s^-1 with respect to the
systemic velocity, is extremely broad, with a FWHM of 130 km s^-1, and has no
detectable high velocity components within 1500 km s^-1 on either side of the
observed line. The unusual line profile led us to suspect that this source,
might belong to a class of megamaser galaxies in which the amplified emission
is the result of an interaction between the radio jet and an encroaching
molecular cloud, rather than occurring in a circumnuclear disk. Our initial
VLBA observations show that the maser emission emanates entirely from a region
<0.25 pc in extent, located toward a continuum component thought to be
associated with the receding jet. The very high linewidth occurring on such
small spatial scales and the rapid variability indicate that the H_2O emission
is likely to arise from a shocked region at the interface between the energetic
jet material and the molecular gas in the cloud where the jet is boring
through. The orientation of the radio jets close to the plane of the sky also
results in shocks with the preferred orientation for strong masers from our
vantage point. Single-dish monitoring with the Effelsberg 100m telescope showed
that the line and continuum emission "flared" on very similar timescales. The
close temporal correlation between this activity in the maser emission and the
continuum flare further suggest that the masing region and the continuum
hotspots are nearly equidistant from the central engine and may be different
manifestations of the same dynamical events.
  (abridged abstract)


title: Galactic Center Molecular Clouds

abstract:
  At a distance of 8 kpc only, the center of the Galaxy provides a unique
testbed for studies about the physics of the interstellar medium and star
formation in the nuclei of galaxies. Since it shares many properties of other,
more spectacular nuclei, a detailed investigation of the Galactic Center is a
necessary step to gain better understanding of the physical processes governing
galactic nuclei in general. We review the characteristics of the central
molecular cloud layer, the physical properties of these clouds, and their
interplay with the magnetic field.


title:
Perspective from a Younger Generation -- The Astro-Spectroscopy of
  Gisbert Winnewisser

abstract:
  Gisbert Winnewisser's astronomical career was practically coextensive with
the whole development of molecular radio astronomy. Here I would like to pick
out a few of his many contributions, which I, personally, find particularly
interesting and put them in the context of newer results.


title: Structure and Stability of Prestellar Cores

abstract:
  Following an approach initially outlined by McKee & Holliman, we investigate
the structure and stability of dense, starless molecular cloud cores. We model
those as spherical clouds in hydrostatic equilibrium and supported against
gravity by thermal, turbulent, and magnetic pressure. We determine the gas
pressure by solving for thermal equilibrium between heating and cooling, while
the turbulent and magnetic pressures are assumed to obey polytropic equations
of state. In comparing the models to observed cloud cores we find that the
observed peak column densities often exceed the limit for stable equilibria
supported by thermal pressure alone, suggesting significant non-thermal
pressure if the cores are to be stable. Non-thermal support is also needed to
stabilize cores embedded in molecular clouds with high average pressures. Since
the observed molecular linewidths of cores suggest that the turbulent pressure
is lower than the thermal pressure, magnetic field are likely a dominant
pressure component in many such cores.


title:
Constraining the Magnetic Effects on HI Rotation Curves and the Need for
  Dark Halos

abstract:
  The density profiles of dark halos are usually inferred from the rotation
curves of disk galaxies based on the assumption that the gas is a good tracer
of the gravitational potential of the galaxies. Some authors have suggested
that magnetic pinching forces could alter significantly the rotation curves of
spiral galaxies. In contrast to other studies which have concentrated in the
vertical structure of the disk, here we focus on the problem of magnetic
confinement in the radial direction to bound the magnetic effects on the HI
rotation curves. It is shown that azimuthal magnetic fields can hardly speed up
the HI disk of galaxies as a whole. In fact, based on virial constraints we
show that the contribution of galactic magnetic fields to the rotation curves
cannot be larger than ~10 km/s at the outermost point of HI detection, if the
galaxies did not contain dark matter at all, and up to 20 km/s in the
conventional dark halo scenario. The procedure to estimate the maximum effect
of magnetic fields is general and applicable to any particular galaxy disk. The
inclusion of the surface terms, namely the intergalactic (thermal, magnetic or
ram) pressure, does not change our conclusions. Other problems related with the
magnetic alternative to dark halos are highlighted. The relevance of magnetic
fields in the cuspy problem of dark halos is also discussed.


title:
Rayleigh Scattering Cross Section Redward of Ly$\alpha$ by Atomic
  Hydrogen

abstract:
  We present a low energy expansion of the Kramers-Heisenberg formula for
atomic hydrogen in terms of $(\omega/\omega_l)$, where $\omega_l$ and $\omega$
are the angular frequencies corresponding to the Lyman limit and the incident
radiation, respectively. The leading term is proportional to
$(\omega/\omega_l)^4$, which admits a well-known classical interpretation. With
higher order terms we achieve accuracy with errors less than 4 % of the
scattering cross sections in the region $\omega/\omega_l\le 0.6$. In the
neighboring region around Ly$\alpha$ ($\omega/\omega_l >0.6$), we also present
an explicit expansion of the Kramers-Heisenberg formula in terms of
$\Delta\omega\equiv (\omega-\omega_{Ly\alpha})/\omega_{Ly\alpha}$. The accuracy
with errors less than 4 % can be attained for $\omega/\omega_l \ge 0.6$ with
the expansion up to the fifth order of $\Delta\omega$. We expect that these
formulae will be usefully applied to the radiative transfer in high neutral
column density regions, including the Gunn-Peterson absorption troughs and
Rayleigh scattering in the atmospheres of giants.


title:
Binaries with Compact Components: Theoretical and Observational
  Challenges

abstract:
  We report on recent progress in our theoretical understanding of X-ray
binaries, which has largely been driven by new observations, and illustrate the
interplay between theory and observations considering as examples
intermediate-mass X-ray binaries, irradiation-driven evolution, ultraluminous
X-ray sources and neutron stars with low-velocity kicks.


title:
Orientations of Spin and Magnetic Dipole Axes of Pulsars in the
  J0737--3039 Binary Based on Polarimetry Observations at the Green Bank
  Telescope

abstract:
  We report here the first polarimetric measurements of the pulsars in the
J0737-3039 binary neutron star system using the Green Bank Telescope. We
conclude both that the primary star (A) has a wide hollow cone of emission,
which is an expected characteristic of the relatively open magnetosphere given
its short spin period, and that A has a small angle between its spin and
magnetic dipole axes, $4\pm 3$ degrees. This near alignment of axes suggests
that A's wind pressure on B's magnetosphere will depend on orbital phase. This
variable pressure is one mechanism for the variation of flux and profile shape
of B with respect to the orbital phase that has been reported. The response of
B to the A wind pressure will also depend on the particular side of its
magnetosphere facing the wind at the spin phase when B is visible. This is a
second possible mechanism for variability. We suggest that B may have its spin
axis aligned with the orbital angular momentum owing to A's wind torque that
contributes to its spindown. Monitoring the pulsars while geodetic precession
changes spin orientations will provide essential evidence to test detailed
theoretical models. We determine the Rotation Measures of the two stars to be
$-112.3\pm 1.5$ and $-118\pm 12$ rad m$^{-2}$.


title:
On the Center Shifts of Raman Scattered He II and H$\alpha$ Wings in
  Symbiotic Stars

abstract:
  Using a Monte Carlo technique, we investigate the center shifts that are
expected to occur for the broad H$\alpha$ wings and the He II $\lambda$ 6545
feature as a function of the neutral hydrogen column density in symbiotic
stars.These two features are proposed to be formed via Raman scattering of UV
continuum around Ly$\beta$ and He II $\lambda$ 1025 emission line by neutral
hydrogen. The branching ratio of Raman scattering to Rayleigh scattering for UV
radiation around Ly$\beta$ is a non-linearly increasing function of the
wavelength, which results in enhanced Raman optical fluxes redward of the
H$\alpha$ line center as $N_{HI}$ increases. However, we find that the amount
of wing center shift is quite small about $20{\rm km s^{-1}}$ as $N_{HI}$
increases from $10^{20}{\rm cm^{-2}}$ to $10^{21}{\rm cm^{-2}}$. Assuming that
He II $\lambda$~1025 emission is characterized by a Gaussian profile, the Raman
scattered He II 6545 feature exhibits near Gaussian profiles with the peak
shifted redward for $N_{HI}<10^{22}{\rm cm^{-2}}$. The redward center shift
amounts to $1{\rm \AA}$ for $N_{HI}\sim 10^{20}{\rm cm^{-2}}$ and decreases as
$N_{HI}$ increases up to $N_{HI}\sim 10^{22}{\rm cm^{-2}}$, above which no
center shift is observed. The redward peak shift is due to the fact that the
incident emission profile is symmetric with respect to He II $\lambda$~1025
line center whereas the Raman conversion rate is increasing towards the line
center of Ly$\beta$. We emphasize that the determination of $N_{HI}$ by
locating the exact peak position of the He II 6545 feature will lift the
degeneracy to allow a more accurate estimate of the covering factor of the
neutral region, providing strong constraints on the mass loss process occurring
in symbiotic stars.


title:
A Hard X-ray survey of the Galactic Center with INTEGRAL/IBIS. Catalog
  of sources

abstract:
  During the period Aug.23-Sept.24 2003, the INTEGRAL observatory performed an
ultra deep survey of the Galactic Center region with a record sensitivity at
energies higher than 20 keV. We have analized images of the Galactic Center
region obtained with the ISGRI detector of the IBIS telescope (15-200 keV) and
present here a catalog of detected sources. In total, 60 sources with a flux
higher than 1.5 mCrab have been detected. 44 of them were earlier identified as
Galactic binary systems, 3 are extragalactic objects. 2 new sources are
discovered.


title:
The MHD Alfven wave oscillation model of kHz Quasi Periodic Oscillations
  of Accreting X-ray Binaries

abstract:
  We ascribe the interpretation of the twin kilohertz Quasi Periodic
Oscillations (kHz QPOs) of X-ray spectra of Low Mass X-Ray Binaries (LMXBs) to
MHD Alfven wave oscillations in the different mass density regions of the
accreted matter at the preferred radius, and the upper kHz QPO frequency
coincides with the Keplerian frequency. The proposed model concludes that the
kHz QPO frequencies depend inversely on the preferred radius, and that
theoretical relation between the upper frequency ($\nt$) and the lower
frequency ($\no$) is $\no \sim \nt^{2}$, which is similar to the measured
empirical relation. The separation between the twin frequencies decreases
(increases) with increasing kHz QPO frequency if the lower kHz QPO frequency is
more (less) than $\sim$ 400 Hz.


title: Seyfert galaxies in UZC-Compact Groups

abstract:
  We present results concerning the occurrence of Seyfert galaxies in a new
automatically selected sample of nearby Compact Groups of galaxies (UZC-CGs).
Seventeen Seyferts are found, constituting ~3% of the UZC-CG galaxy population.
CGs hosting and non-hosting a Seyfert member exhibit no significant
differences, except that a relevant number of Sy2 is found in unusual CGs, all
presenting large velocity dispersion (sigma > 400 km/s), many neighbours and a
high number of ellipticals. We also find that the fraction of Seyferts in CGs
is 3 times as large as that among UZC-single-galaxies, and results from an
excess of Sy2s. CG-Seyferts are not more likely than other CG galaxies to
present major interaction patterns, nor to display a bar. Our results
indirectly support the minor-merging fueling mechanism.


title:
The Environmental Dependence of the Relations between Stellar Mass,
  Structure, Star Formation and Nuclear Activity in Galaxies

abstract:
  We use a complete sample of galaxies drawn from the SDSS to study how
structure, star formation and nuclear activity depend on local density and on
stellar mass. Local density is estimated by counting galaxies above a fixed
absolute magnitude limit within cylinders 2 Mpc in projected radius and +-500
km/s in depth. The stellar mass distribution of galaxies shifts by nearly a
factor of two towards higher masses between low and high density regions. At
fixed stellar mass, both star formation and nuclear activity depend strongly on
local density, while structural parameters such as size and concentration are
almost independent of it. The galaxy property most sensitive to environment is
specific star formation rate. For galaxies with stellar masses less than 3 x
10^10 M_sun, the median SFR/M* decreases by more than a factor of 10 from low
to high densities. This decrease is less marked for massive galaxies. At fixed
stellar mass, twice as many galaxies host AGN with strong [OIII] emission in
low density regions as in high. Massive galaxies in low-density environments
also contain more dust. We have analyzed correlations between spectroscopic
indicators that probe SFH on different timescales (D4000, Hdelta_A and SFR/M*).
The correlations do not depend on environment, suggesting that the decrease in
star formation has ocurred over long (>1 Gyr) timescales. Since structure does
not depend on environment for more massive galaxies, trends in recent SFH, dust
and AGN for these systems cannot be driven by processes that alter structure,
e.g. mergers. The SFH-density correlation is strongest for small scale (< 1
Mpc) estimates of local density. Finally, we highlight a striking similarity
between changes in the galaxy population as a function of density and as a
function of redshift and we interpret this using N-body simulations.


title:
AX J0049.4-7323 - a close look at a neutron star interacting with a
  circumstellar disk

abstract:
  Detailed evidence on the system AX J0049.4-7323 is presented here to show how
the passage of the neutron star in the binary system disrupts the circumstellar
disk of the mass donor Be star. A similar effect is noted in three other
Be/X-ray binary systems. Together the observational data should provide
valuable tools for modelling these complex interactions.


title: Testing the paradigm of adiabaticity

abstract:
  We introduce the concepts of adiabatic (curvature) and isocurvature (entropy)
cosmological perturbations and present their relevance for parameter estimation
from cosmic microwave background anisotropies data. We emphasize that, while
present-day data are in excellent agreement with pure adiabaticity, subdominant
isocurvature contributions cannot be ruled out. We discuss model independent
constraints on the isocurvature contribution. Finally, we argue that the Planck
satellite will be able to do precision cosmology even if the assumption of
adiabaticity is relaxed.


title: Wimp/Neutralino Direct Detection

abstract:
  The most popular candidate for non baryonic dark matter is the neutralino.
More than twenty experiments are dedicated to its direct detection. This review
describes the most competitive and promising experiments with different
detection techniques. The most recent results are presented with some prospects
for the near future.


title: Circumstellar dust shells of hot post-AGB stars

abstract:
  Using a radiative transfer code (DUSTY) parameters of the circumstellar dust
shells of 15 hot post-AGB stars have been derived. Combining the optical, near
and far-infrared (ISO, IRAS) data of the stars, we have reconstructed their
spectral energy distributions (SEDs) and estimated the dust temperatures, mass
loss rates, angular radii of the inner boundary of the dust envelopes and the
distances to these stars. The mass loss rates
(10$^{-6}-10^{-5}$M$_{\odot}$yr$^{-1}$) are intermediate between stars at the
tip of the AGB and the PN phase. We have also studied the ISO spectra of 7 of
these stars. Amorphous and crystalline silicate features were observed in
IRAS14331-6435 (Hen3-1013), IRAS18062+2410 (SAO85766) and IRAS22023+5249 (LSIII
+5224) indicating oxygen-rich circumstellar dust shells. The presence of
unidentified infrared (UIR) band at 7.7$\mu$, SiC emission at 11.5$\mu$ and the
"26$\mu$" and "main 30$\mu$" features in the ISO spectrum of IRAS17311-4924
(Hen3-1428) suggest that the central star may be carbon-rich. The ISO spectrum
of IRAS17423-1755 (Hen3-1475) shows a broad absorption feature at 3.1$\mu$ due
to C$_{2}$H$_{2}$ and/or HCN which is usually detected in the circumstellar
shells of carbon-rich stars.


title: X Ray Observations of Classical and recurrent Novae in Outburst

abstract:
  I review X-ray observations of classical and recurrent novae in outburst.
Significant X-ray flux is emitted by the nova shell, with a peak luminosity up
to 10**35 erg/cm**2/s in the 0.2-10 keV range.In recurrent nova systems, or in
novae hosting a red giant, the source of X-rays may be previous circumstellar
matter shocked by the nova wind. However, for most classical novae, X-rays
originate inside the nebula ejected in the outburst. The data indicate a very
high fraction of shocked material, and a non-smooth, varying wind outflow. A
nebular emission line spectrum is also observed at late phases. In about half
of the observed novae, the central white dwarf appears as a very luminous
supersoft X-ray source for 1 to 9 years after the outburst. It is the best type
of object to study the characteristics of shell hydrogen burning on white
dwarfs in single degenrate systems. The available statistics indicate that the
duration of the supersoft X-ray phase is peaked around 2 years. Recently,
``template grating spectra'' with high S/N have been obtained for V4743 Sgr.
  The X-ray light curve of this nova reveals a rich and complex power spectrum,
with signatures of non-radial g-mode oscillations of the white dwarf. The
oscillations and the spectra allow to determine the properties of the shell
hydrogen burning white dwarf.


title:
On the discovery of an enormous ionized halo around the hot DO white
  dwarf PG1034+001

abstract:
  Very recently, the discovery of the largest known planetary nebula on the sky
surrounding the DO white dwarf PG1034+001 with an apparent diameter of about 2
degrees, corresponding to a linear diameter of 3.5 - 7.0 pc at the likely
distance of 100 - 200 pc, has been reported by Hewett et al. (2003). A careful
inspection of available sky survey data has now shown that this planetary
nebula, Hewett 1, is surrounded by an elliptical emission shell with an
apparent diameter of 6 times 9 degrees (16.2 +6.1/-4.5 times 24.3 +9.1/-6.8 pc
at d = 155 +58/-43 pc. A further emission structure, detected northeast of the
central star may indicate another shell with a size of 10 times 16 degr. From
presently available observational data we do not have indications whether the
emission arises from material which was ejected from PG1034+001 or from ionized
ambient ISM.
  Improved proper motion data combined with radial velocity and distance from
the literature have enabled us to derive a Galactic orbit for the central star
PG1034+001. Its thin disk orbit and the morphology of the first halo suggest
that the nebula is in an advanced stage of interaction with the interstellar
medium.


title: PAHs and crystalline silicates in the post-AGB star IRAS 16279-4757

abstract:
  IRAS 16279-4757 belongs to a group of post-AGB stars showing both PAH bands
and crystalline silicates. We present mid-infrared images, that resolve the
object for the first time. The morphology is similar to that of the `Red
Rectangle' (HD 44179), the prototype object with PAHs and crystalline
silicates. A two-component model and images suggest a dense oxygen-rich torus,
an inner, low-density carbon-rich region and a carbon-rich bipolar outflow. The
PAH bands are enhanced at the outflow, while the continuum emission is
concentrated towards the center. Our findings support the suggestion that mixed
chemistry and morphology are closely related. We discuss the ISO/SWS spectra of
IRAS 16279-4757. Several bands in the ISO/SWS spectrum show a match with
anorthite: this would be the first detection of this mineral outside the solar
system. Compared to HD 44179, the shapes of PAH bands are closer to those of
planetary nebulae, possibly related to a population of small PAHs present HD
44179, but absent around IRAS 16279-4757. Detailed examination of the spectra
shows the individual character of these two objects. The comparison suggests
that the torus found in IRAS 16279-4757 may have formed more recently than that
in HD 44179.


title: Gravoturbulent Fragmentation

abstract:
  We discuss star formation in the turbulent interstellar medium. We argue that
morphological appearance and dynamical evolution of the gas is primarily
determined by supersonic turbulence, and that stars form via a process we call
gravoturbulent fragmentation. Turbulence that is dominated by large-scale
shocks or is free to decay leads to an efficient, clustered, and synchronized
mode of star formation. On the other hand, when turbulence carries most of its
energy on very small scales star formation is inefficient and biased towards
single objects. The fact that Galactic molecular clouds are highly filamentary
can be explained by a combination of compressional flows and shear. Some
filaments may accumulate sufficient mass and density to become gravitationally
unstable and form stars. This is observed in the Taurus molecular cloud.
Timescales and spatial distribution of protostars are well explained by the
linear theory of gravitational fragmentation of filaments. The dynamical
evolution, especially at late times, and the final mass distribution strongly
depend on the global properties of the turbulence. In dense embedded clusters
mutual protostellar interactions and competition for the available mass
reservoir lead to considerable stochastic variations between the mass growth
histories of individual stars.


title: L1521E: the first starless core with no molecular depletion

abstract:
  L1521E seems unique among starless cores. It stands out in a distribution of
a ratio (R) that we define to asses core evolution, and which compares the
emission of the easily-depleted C18O molecule with that of the hard to deplete,
late-time species N2H+. While all cores we have studied so far have R ratio
lower than 1, L1521E has an R value of 3.4, which is 8 times the mean of the
other cores. To understand this difference, we have modeled the C18O and N2H+
abundance profiles in L1521E using a density distribution derived from 1.2mm
continuum data. Our model shows that the C18O emission in this core is
consistent with constant abundance, and this makes L1521E the first core with
no C18O depletion. Our model also derives an unusually low N2H+ abundance.
These two chemical peculiarities suggest that L1521E has contracted to its
present density very recently, and it is therefore an extremely young starless
core. Comparing our derived abundances with a chemical model, we estimate a
tentative age of 1.5 x 10^5 yr, which is too short for ambipolar diffusion
models.


title: A New View of the Supersoft X-Ray Source Cal 87 Observed with XMM-Newton

abstract:
  Cal 87 was observed with XMM-Newton in April of 2003. The source shows a rich
emission line spectrum, where lines can be identified if they are red-shifted
by 700-1200 km/s. These lines seem to have been emitted in a wind from the
system. The eclipse is observed to be shifted in phase by 0.03 phi(orb), where
phi(orb) is the phase of the optical light curve.


title: A stroboscopic method for phase resolved pulsar observations

abstract:
  We present a stroboscopic system developed for optical observations of
pulsars and its application in the CLYPOS survey. The stroboscopic device is
connected to a GPS clock and provides absolute timing to the stroboscopic
shutter relative to the pulsar's radio ephemerides. By changing the phase we
can examine the pulsar's light curve. The precisely timed stroboscope in front
of the CCD camera can perform highly accurate time resolved pulsar photometry
and offers the advantages of CCD cameras, which are high quantum efficiency as
well as relatively large field of view, which is important for flux
calibrations.
  CLYPOS (Cananea Ljubljana Young Pulsar Optical Survey) is an extensive search
for optical counterparts of about 30 northern hemisphere radio pulsars. It is a
collaboration between the INAOE, Mexico and the Faculty of Mathematics and
Physics of the University of Ljubljana. Stroboscopic observations were done
between December 1998 and November 2000 at the 2.12 m telescope of the
Observatory Guillermo Haro in Cananea, Sonora. The first results of the survey
are presented. Analyzed data indicate that there is no optical counterpart
brighter than ~22.


title: SDSS J1240-01: A New AM CVn Candidate from the Sloan Digital Sky Survey

abstract:
  We report on the discovery of a new AM CVn candidate from the Sloan Digital
Sky Survey, Data Release 1. Our first spectroscopic follow-up in the optical is
presented and discussed briefly.