title: Tests of Gaussianity

abstract:
  We review two powerful methods to test the Gaussianity of the cosmic
microwave background (CMB): one based on the distribution of spherical wavelet
coefficients and the other on smooth tests of goodness-of-fit. The spherical
wavelet families proposed to analyse the CMB are the Haar and the Mexican Hat
ones. The latter is preferred for detecting non-Gaussian homogeneous and
isotropic primordial models containing some amount of skewness or kurtosis.
Smooth tests of goodness-of-fit have recently been introduced in the field
showing some interesting properties. We will discuss the smooth tests of
goodness-of-fit developed by Rayner and Best for the univariate as well as for
the multivariate analysis.


title: Direct Dark Matter Searches

abstract:
  The elucidation of the nature of dark matter is one of the challenging tasks
in astroparticle physics. A brief overview on the different methods to search
directly for dark matter in form of Weakly Interacting Massive Particles
(WIMPs) is given.


title: Magnetic Bubbles in Galaxy Clusters

abstract:
  I discuss Chandra X-ray Observatory measurements of cavities in galaxy
clusters and their implications for heating the intracluster gas. The emerging
paradigm for cooling flows has important implications for understanding
self-regulated galaxy formation.


title:
The origin of HI-deficiency in galaxies on the outskirts of the Virgo
  cluster. I. How far can galaxies bounce out of clusters?

abstract:
  Spiral galaxies that are deficient in neutral Hydrogen are observed on the
outskirts of the Virgo cluster. If their orbits have crossed the inner parts of
the cluster, their interstellar gas may have been lost through ram pressure
stripping by the hot X-ray emitting gas of the cluster. We estimate the maximum
radius out to which galaxies can bounce out of a virialized system using
analytical arguments and cosmological N-body simulations. In particular, we
derive an expression for the turnaround radius in a flat cosmology with a
cosmological constant that is simpler than previously derived expressions. We
find that the maximum radius reached by infalling galaxies as they bounce out
of their cluster is roughly between 1 and 2.5 virial radii. Comparing to the
virial radius of the Virgo cluster, which we estimate from X-ray observations,
these HI-deficient galaxies appear to lie significantly further away from the
cluster center. Therefore, if their distances to the cluster core are correct,
the HI-deficient spiral galaxies found outside of the Virgo cluster cannot have
lost their gas by ram pressure from the hot intracluster gas.


title:
Application of Model Derived Charge Transfer Inefficiency Corrections to
  STIS Spectroscopic CCD Data

abstract:
  The ST-ECF Calibration Enhancement effort for the Space Telescope Imaging
Spectrograph (STIS) aims to improve data calibration via the application of
physical modelling techniques. As part of this effort we have developed a model
of the STIS CCD readout process. The model itself is described in some detail
in earlier ISRs. Here we consider the application to STIS spectroscopic data.
We find good agreement between the simulation derived corrections and empirical
corrections for a range of background and source levels. Moreover we find that,
where the two differ, because only the simulation properly accounts for the
charge distribution in the array.


title: CMB polarization from secondary vector and tensor modes

abstract:
  We consider a novel contribution to the polarization of the Cosmic Microwave
Background induced by vector and tensor modes generated by the non-linear
evolution of primordial scalar perturbations. Our calculation is based on
relativistic second-order perturbation theory and allows to estimate the
effects of these secondary modes on the polarization angular power-spectra. We
show that a non-vanishing B-mode polarization unavoidably arises from pure
scalar initial perturbations, thus limiting our ability to detect the signature
of primordial gravitational waves generated during inflation. This secondary
effect dominates over that of primordial tensors for an inflationary
tensor-to-scalar ratio $r<10^{-6}$. The magnitude of the effect is smaller than
the contamination produced by the conversion of polarization of type E into
type B, by weak gravitational lensing. However the lensing signal can be
cleaned, making the secondary modes discussed here the actual background
limiting the detection of small amplitude primordial gravitational waves.


title: CO emission associated with a cooling flow

abstract:
  The existence of cooling flows in the center of galaxy clusters has always
been a puzzle, and in particular the fate of the cooling gas, since the
presence of cold gas has never been proven directly. X-ray data from the
satellites Chandra and XMM-Newton have constrained the amount of cooling, and
it was realized that feedback and heating from a central AGN and its jets could
reduce the amount of cold gas.
  Recently, a few central galaxies of cooling flow clusters have been detected
in the CO lines. For the first time, we show IRAM interferometer maps of
CO(1-0) and CO(2-1) emission in a cooling flow, showing a clear association of
the cold gas (at about 20K) with the cooling flow. This shows that although the
AGN provides a feedback heating, the cooling phenomenon does occur, with about
the expected rate.


title: Thermal and Non-thermal X-Rays from the LMC Super Bubble 30 Dor C

abstract:
  We report on the discovery of thermal and non-thermal X-rays from the shells
of the super bubble (SB) 30 Dor C in the Large Magellanic Cloud (LMC). The
X-ray morphology is a nearly circular shell with a radius of about 40 pc, which
is bright on the northern and western sides. The spectra of the shells are
different from region to region. The southern shell shows clear emission lines,
and is well fitted with a model of a thin-thermal plasma (kT = 0.21keV) in
non-equilibrium ionization (NEI) plus a power-law component. This thermal
plasma is located inside of the H alpha emission, which is the outer edge of
the shell of the SB. The northern and western sides of the SB are dim in H
alpha emission, but are bright in non-thermal (power-law) X-rays with a photon
index of 2.1-2.9. The non-thermal X-ray shell traces the outer boundary of the
radio shell. These features of thin-thermal and non-thermal X-rays are similar
to those of SN 1006, a prototype of synchrotron X-ray shell, but the
non-thermal component of 30 Dor C is about ten-times brighter than that of SN
1006. 30 Dor C is the first candidate of an extragalactic SB, in which
energetic electrons are accelerating in the shell. The age is much older than
that of SN 1006, and hence the particle acceleration time in this SB may be
longer than those in normal shell-like SNRs. We found point-like sources
associated with some of tight star clusters. The X-ray luminosity and spectrum
are consistent with those of young clusters of massive stars. Point-like
sources with non-thermal spectra are also found in the SB. These may be
background objects (AGNs) or stellar remnants (neutron stars or black holes).


title:
Application of Model Derived Charge Transfer Inefficiency Corrections to
  STIS Photometric CCD Data

abstract:
  The STECF Calibration Enhancement effort for the Space Telescope Imaging
Spectrograph (STIS) aims to improve data calibration via the application of
physical modelling techniques. As part of this effort we have developed a model
of the STIS CCD readout process. The model itself is described in some detail
in earlier ISRs. Here we consider the application to STIS photometric data. We
demonstrate that this approach can successfully remove the trails typically
seen in CTE affected data and go on to ask whether this charge is being
restored to the cores of detected objects in the correct quantities. We find
good agreement between the simulation derived corrections and empirical
corrections for a range of background and source levels. Moreover we find that,
where the two differ, it is because only the simulation properly accounts for
the charge distribution in the array.


title:
Effects of Stellar-Mass and the ISM on the Evolving Morphologies of
  Planetary Nebulae

abstract:
  A significant step forward in the understanding of Planetary Nebula (PN)
formation can be achieved by exploring the connection of PN with stellar
evolution. In particular, the initial mass of the star plays a crucial role, as
it determines the evolutionary timescales, the density structure of the gas and
the amount of energy injected into the nebula. Here we summarize our study of
the effects of stellar mass in PN formation. Our numerical simulations include
the evolution of the stellar wind for different initial progenitor masses and
the influence of the ISM. We also investigate how the systemic velocity of the
star with respect to its surrounding medium affects the PN formation. We find
that unless the star is moving, most of the mass lost by PN progenitors can be
found in the low surface brightness extended halos, where the stellar ejecta is
mixed with ISM material. For a moving central star, the interaction with the
ISM considerably reduces the mass of the circumstellar envelope during the AGB
and PN phases owing to ram pressure stripping.


title:
Cosmic Shear from STIS pure parallels: III. Analysis of Cycle 9 pure
  parallels

abstract:
  Following the detection of a cosmic shear signal at the 30'' scale using
archival parallel data from the STIS CCD camera onboard HST in Haemmerle et al.
(2002), we analyzed a larger data set obtained from an HST GO pure parallel
program. Although this data set is considerably larger than the one analyzed
previously, we do not obtain a significant detection of the cosmic shear
signal. The potential causes of this null result are the multiple systematics
that plague the STIS CCD data, and in particular the degradation of the CCD
charge transfer efficiency after 4 years in space.


title:
Star Captures by Quasar Accretion Disks: A Possible Explanation of the
  M-sigma Relation

abstract:
  A new theory of quasars is presented in which the matter of thin accretion
disks around black holes is supplied by stars that plunge through the disk.
Stars in the central part of the host galaxy are randomly perturbed to highly
radial orbits, and as they repeatedly cross the disk they lose orbital energy
by drag, eventually merging into the disk. Requiring the rate of stellar mass
capture to equal the mass accretion rate into the black hole, a relation
between the black hole mass and the stellar velocity dispersion is predicted of
the form M_{BH} \propto sigma_*^{30/7}. The normalization depends on various
uncertain parameters such as the disk viscosity, but is consistent with
observation for reasonable assumptions. We show that a seed central black hole
in a newly formed stellar system can grow at the Eddington rate up to this
predicted mass via stellar captures by the accretion disk. Once this mass is
reached, star captures are insufficient to maintain an Eddington accretion
rate, and the quasar may naturally turn off as the accretion switches to a
low-efficiency advection mode. The model provides a mechanism to deliver mass
to the accretion disk at small radius, probably solving the problem of
gravitational instability to star formation in the disk at large radius. We
note that the matter from stars that is incorporated to the disk has an average
specific angular momentum that is very small or opposite to that of the disk,
and discuss how a rotating disk may be maintained as it captures this matter if
a small fraction of the accreted mass comes from stellar winds that form a disk
extending to larger radius. We propose several observational tests and
consequences of this theory.


title: Axion bremsstrahlung from collisions of global strings

abstract:
  We calculate axion radiation emitted in the collision of two straight global
strings. The strings are supposed to be in the unexcited ground state, to be
inclined with respect to each other, and to move in parallel planes. Radiation
arises when the point of minimal separation between the strings moves faster
than light. This effect exhibits a typical Cerenkov nature. Surprisingly, it
allows an alternative interpretation as bremsstrahlung under a collision of
point charges in 2+1 electrodynamics. This can be demonstrated by suitable
world-sheet reparameterizations and dimensional reduction. Cosmological
estimates show that our mechanism generates axion production comparable with
that from the oscillating string loops and may lead to further restrictions on
the axion window.


title:
Synthetic Observations of Simulated Radio Galaxies I: Radio and X-ray
  Analysis

abstract:
  We present an extensive synthetic observational analysis of numerically-
simulated radio galaxies designed to explore the effectiveness of conventional
observational analyses at recovering physical source properties. These are the
first numerical simulations with sufficient physical detail to allow such a
study. The present paper focuses on extraction of magnetic field properties
from nonthermal intensity information. Synchrotron and inverse-Compton
intensities provided meaningful information about distributions and strengths
of magnetic fields, although considerable care was called for. Correlations
between radio and X-ray surface brightness correctly revealed useful dynamical
relationships between particles and fields. Magnetic field strength estimates
derived from the ratio of X-ray to radio intensity were mostly within about a
factor of two of the RMS field strength along a given line of sight. When
emissions along a given line of sight were dominated by regions close to the
minimum energy/equipartition condition, the field strengths derived from the
standard power-law-spectrum minimum energy calculation were also reasonably
close to actual field strengths, except when spectral aging was evident.
Otherwise, biases in the minimum- energy magnetic field estimation mirrored
actual differences from equipartition. The ratio of the inverse-Compton
magnetic field to the minimum-energy magnetic field provided a rough measure of
the actual total energy in particles and fields in most instances, within an
order of magnitude. This may provide a practical limit to the accuracy with
which one may be able to establish the internal energy density or pressure of
optically thin synchrotron sources.


title:
Once again about the origin of the system of the giant stellar arcs in
  the Large Magellanic Cloud

abstract:
  The origin of the arc-shaped stellar complexes in the LMC4 region is still
unknown. These perfect arcs could not have been formed by O-stars and SNe in
their centers; the strong arguments exist also against the possibility of their
formation from infalling gas clouds. The origin from microquasars/GRB jets is
not excluded, because there is the strong concentration of X-ray binaries in
the same region and the massive old cluster NGC 1978, probable site of
formation of binaries with compact components, is there also. The last
possibility is that the source of energy for formation of the stellar arcs and
the LMC4 supershell might be the the giant jet from the nucleus of the Milky
Way, which might be active a dozen Myr ago.


title:
Mid-infrared spectral evidence for a luminous dust enshrouded source in
  Arp220

abstract:
  We have re-analyzed the 6-12 micron ISO spectrum of the ultra-luminous
infrared galaxy Arp220 with the conclusion that it is not consistent with that
of a scaled up version of a typical starburst. Instead, both template fitting
with spectra of the galaxies NGC4418 and M83 and with dust models suggest that
it is best represented by combinations of a typical starburst component,
exhibiting PAH emission features, and a heavily absorbed dust continuum which
contributes ~40% of the 6-12 micron flux and likely dominates the luminosity.
Of particular significance relative to previous studies of Arp220 is the fact
that the emission feature at 7.7 micron comprises both PAH emission and a
broader component resulting from ice and silicate absorption against a heavily
absorbed continuum. Extinction to the PAH emitting source, however, appears to
be relatively low. We tentatively associate the PAH emitting and heavily
dust/ice absorbed components with the diffuse emission region and the two
compact nuclei respectively identified by Soifer et al. (2002) in their higher
spatial resolution 10 micron study. Both the similarity of the absorbed
continuum with that of the embedded Galactic protostars and results of the dust
models imply that the embedded source(s) in Arp220 could be powered by, albeit
extremely dense, starburst activity. Due to the high extinction, it is not
possible with the available data to exclude that AGN(s) also contribute some or
all of the observed luminosity. In this case, however, the upper limit measured
for its hard X-ray emission would require Arp220 to be the most highly obscured
AGN known.


title: The XMM-Newton view of the X-ray halo and jet of NGC 6251

abstract:
  We present an XMM observation of the radio jet and diffuse halo of the nearby
radio galaxy NGC6251. The EPIC spectrum of the galaxy's halo is best-fitted by
a thermal model with temperature kT~1.6 keV and subsolar abundances.
Interestingly, an additional hard X-ray component is required to fit the EPIC
spectra of the halo above 3 keV, and is independently confirmed by an archival
Chandra observation. However, its physical origin is not clear. Contribution
from a population of undetected Low Mass X-ray Binaries seems unlikely.
Instead, the hard X-ray component could be due to inverse Compton scattering of
the CMB photons off relativistic electrons scattered throughout the halo of the
galaxy, or non-thermal bremsstrahlung emission. The IC/CMB interpretation,
together with limits on the diffuse radio emission, implies a very weak
magnetic field, while a non-thermal bremsstrahlung origin implies the presence
of a large number of very energetic electrons. We also detect X-ray emission
from the outer (~3.5') jet, confirming previous ROSAT findings. Both the EPIC
and ACIS spectra of the jet are best-fitted by a power law with photon index
\~1.2. A thermal model is formally ruled out by the data. Assuming an origin of
the X-rays from the jet via IC/CMB, as suggested by energetic arguments, and
assuming equipartition implies a large Doppler factor (delta~10).
Alternatively, weaker beaming is possible for magnetic fields several orders of
magnitude lower than the equipartition field.


title: Cosmological parameters from SDSS and WMAP

abstract:
  We measure cosmological parameters using the three-dimensional power spectrum
P(k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in
combination with WMAP and other data. Our results are consistent with a
``vanilla'' flat adiabatic Lambda-CDM model without tilt (n=1), running tilt,
tensor modes or massive neutrinos. Adding SDSS information more than halves the
WMAP-only error bars on some parameters, tightening 1 sigma constraints on the
Hubble parameter from h~0.74+0.18-0.07 to h~0.70+0.04-0.03, on the matter
density from Omega_m~0.25+/-0.10 to Omega_m~0.30+/-0.04 (1 sigma) and on
neutrino masses from <11 eV to <0.6 eV (95%). SDSS helps even more when
dropping prior assumptions about curvature, neutrinos, tensor modes and the
equation of state. Our results are in substantial agreement with the joint
analysis of WMAP and the 2dF Galaxy Redshift Survey, which is an impressive
consistency check with independent redshift survey data and analysis
techniques. In this paper, we place particular emphasis on clarifying the
physical origin of the constraints, i.e., what we do and do not know when using
different data sets and prior assumptions. For instance, dropping the
assumption that space is perfectly flat, the WMAP-only constraint on the
measured age of the Universe tightens from t0~16.3+2.3-1.8 Gyr to
t0~14.1+1.0-0.9 Gyr by adding SDSS and SN Ia data. Including tensors, running
tilt, neutrino mass and equation of state in the list of free parameters, many
constraints are still quite weak, but future cosmological measurements from
SDSS and other sources should allow these to be substantially tightened.


title: Testing Massive Star Formation Theory in Orion

abstract:
  I compare theoretical models of massive star formation with observations of
the Orion Hot Core, which harbors one of the closest massive protostars.
Although this region is complicated, many of its features (size, luminosity,
accretion disk, HII region, outflow) may be understood by starting with a
simple model in which the star forms from a massive gas core that is a coherent
entity in approximate pressure balance with its surroundings. The dominant
contribution to the pressure is from turbulent motions and magnetic fields. The
collapse can be perturbed by interactions with other stars in the forming
cluster, which may induce sporadic enhancements of the accretion and outflow
rate.


title: The 3D power spectrum of galaxies from the SDSS

abstract:
  We measure the large-scale real-space power spectrum P(k) using a sample of
205,443 galaxies from the Sloan Digital Sky Survey, covering 2417 square
degrees with mean redshift z~0.1. We employ a matrix-based method using
pseudo-Karhunen-Loeve eigenmodes, producing uncorrelated minimum-variance
measurements in 22 k-bands of both the clustering power and its anisotropy due
to redshift-space distortions, with narrow and well-behaved window functions in
the range 0.02 h/Mpc < k < 0.3h/Mpc. We pay particular attention to modeling,
quantifying and correcting for potential systematic errors, nonlinear redshift
distortions and the artificial red-tilt caused by luminosity-dependent bias.
Our final result is a measurement of the real-space matter power spectrum P(k)
up to an unknown overall multiplicative bias factor. Our calculations suggest
that this bias factor is independent of scale to better than a few percent for
k<0.1h/Mpc, thereby making our results useful for precision measurements of
cosmological parameters in conjunction with data from other experiments such as
the WMAP satellite. As a simple characterization of the data, our measurements
are well fit by a flat scale-invariant adiabatic cosmological model with h
Omega_m =0.201+/- 0.017 and L* galaxy sigma_8=0.89 +/- 0.02 when fixing the
baryon fraction Omega_b/Omega_m=0.17 and the Hubble parameter h=0.72;
cosmological interpretation is given in a companion paper.


title:
The Effect of Neutron Star Rotation on the Properties of Thermonuclear
  X-ray Bursts

abstract:
  Previously, observations with the Rossi X-ray Timing Explorer showed that
millisecond oscillations occur preferentially in thermonuclear X-ray bursts
with photospheric radius expansion from sources rotating near 600 Hz, while
they occur with equal likelihood in X-ray bursts with and without radius
expansion for sources rotating near 300 Hz. With a larger sample of data than
in previous studies, we find that the detectability of the oscillations is not
directly determined by the properties of the X-ray bursts. Instead, we find
that (1) the oscillations are observed almost exclusively when the accretion
rate onto the neutron star is high, but that (2) radius expansion is only
observed at high accretion rates from the 600 Hz sources, whereas it occurs
only at low accretion rates in the 300 Hz sources. The persistent millisecond
pulsars provide the only apparent exceptions to these trends. The first result
might be explained if the oscillation amplitudes are attenuated at low
accretion rates by an extended electron corona. The second result indicates
that the rotation period of the neutron star determines how the burst
properties vary with accretion rate, possibly through the differences in the
effective surface gravity or the strength of the Coriolis force.


title: A giant flare on a t tauri star observed at millimeter wavelengths

abstract:
  We have conducted multi-epoch synthesis imaging of 2 and 3 millimeter (mm)
continuum emission and near infrared K band 2.2 um imaging of a flare event in
January 2003 that occurred on the young stellar object GMR-A which is suggested
to be a weak-line T Tauri star in the Orion cluster. Our mm data showed that
the flare activity lasted at least over 13 days, whereas the K-band magnitude
did not change during this event. In addition, we have succeeded in detecting
short time variations of flux on the time scales of 15 minutes. The total
energy of the flare is estimated to be 10^{35-36} erg, which makes it one of
the most energetic flares reported to date. Comparing the mm continuum
luminosities with reported X-ray luminosities, we conclude that the mm flare
was similar in nature to solar and other stellar flares. Our results will be a
crucial step toward understanding magnetically induced stellar surface
activities in T Tauri stars.


title:
An Intercomparison Between Divergence-Cleaning and Staggered Mesh
  Formulations for Numerical Magnetohydrodynamics

abstract:
  In recent years, several different strategies have emerged for evolving the
magnetic field in numerical MHD. Some of these methods can be classified as
divergence-cleaning schemes, where one evolves the magnetic field components
just like any other variable in a higher order Godunov scheme. The fact that
the magnetic field is divergence-free is imposed post-facto via a
divergence-cleaning step. Other schemes for evolving the magnetic field rely on
a staggered mesh formulation which is inherently divergence-free. The claim has
been made that the two approaches are equivalent. In this paper we
cross-compare three divergence-cleaning schemes based on scalar and vector
divergence-cleaning and a popular divergence-free scheme. All schemes are
applied to the same stringent test problem. Several deficiencies in all the
divergence-cleaning schemes become clearly apparent with the scalar
divergence-cleaning schemes performing worse than the vector
divergence-cleaning scheme. The vector divergence-cleaning scheme also shows
some deficiencies relative to the staggered mesh divergence-free scheme. The
differences can be explained by realizing that all the divergence-cleaning
schemes are based on a Poisson solver which introduces a non-locality into the
scheme, though other subtler points of difference are also catalogued. By using
several diagnostics that are routinely used in the study of turbulence, it is
shown that the differences in the schemes produce measurable differences in
physical quantities that are of interest in such studies.


title:
The visual orbits of the spectroscopic binaries HD 6118 and HD 27483
  from the Palomar Testbed Interferometer

abstract:
  We present optical interferometric observations of two double-lined
spectroscopic binaries, HD 6118 and HD 27483, taken with the Palomar Testbed
Interferometer (PTI) in the K band. HD 6118 is one of the most eccentric
spectroscopic binaries and HD 27483 a spectroscopic binary in the Hyades open
cluster. The data collected with PTI in 2001-2002 allow us to determine
astrometric orbits and when combined with the radial velocity measurements
derive all physical parameters of the systems. The masses of the components are
2.65 +/- 0.27 M_Sun and 2.36 +/- 0.24 M_Sun for HD 6118 and 1.38 +/- 0.13 M_Sun
and 1.39 +/- 0.13 M_Sun for HD 27483. The apparent semi-major axis of HD 27483
is only 1.2 mas making it the closest binary successfully observed with an
optical interferometer.


title: Pulsar Wind Nebulae and Their Supernovae

abstract:
  Young supernova remnants that contain pulsar wind nebulae provide diagnostics
for both the inner part of the supernova and the interaction with the
surrounding medium, providing an opportunity to relate these objects to
supernova types. Among observed young nebulae, there is evidence for a range of
supernova types, including Type IIP (Crab Nebula and SN 1054) and Type
IIb/IIn/IIL (G292.0+1.8).


title: Electrodynamics of pulsar magnetospheres

abstract:
  I review the theoretical understanding of the global structure of pulsar
magnetospheres concentrating on recent progress in force-free electrodynamics
and first-principles simulations of magnetospheres.


title:
Structuring the HD 141569 A circumstellar dust disk. Impact of eccentric
  bound stellar companions

abstract:
  Scattered light images of the optically thin dust disk around the 5 Myr old
star HD141569 have revealed its complex asymmetric structure. We show in this
paper that the surface density inferred from the observations presents
similarities with that expected from a circumprimary disk within a highly
eccentric binary system. We assume that either the two M stars in the close
vicinity of HD141569 are bound companions or at least one of them is an
isolated binary companion. We discuss the resulting interaction with an
initially axisymmetric disk. This scenario accounts for the formation of a
spiral structure, a wide gap in the disk and a broad faint extension outside
the truncation radius of the disk after 10-15 orbital periods with no need for
massive companion(s) in the midst of the disk resolved in scattered light. The
simulations match the observations and the star age if the perturber is on an
elliptic orbit with a periastron distance of 930 AU and an eccentricity from
0.7 to 0.9. We find that the numerical results can be reasonably well
reproduced using an analytical approach proposed to explain the formation of a
spiral structure by secular perturbation of a circumprimary disk by an external
bound companion. We also interpret the redness of the disk in the visible
reported by Clampin et al.(2003) and show that short-lived grains one order of
magnitude smaller than the blow-out size limit are abundant in the disk. The
most probable reason for this is that the disk sustains high collisional
activity. Finally we conclude that additional processes are required to clear
out the disk inside 150 AU and that interactions with planetary companions
possibly coupled with the remnant gas disk are likely candidates.


title: Radio Identification of the X-ray Jet in the z=4.3 Quasar GB 1508+5714

abstract:
  The recent discovery of an X-ray jet in the z=4.3 quasar GB 1508+5714 by Yuan
et al. (astro-ph/0309318) and Siemiginowska et al. (astro-ph/0310241) prompted
a search for its radio counterpart. Here, we report the successful discovery of
faint radio emission from the jet at 1.4 GHz using archival VLA data. The X-ray
emission is best interpreted as inverse Compton (IC) emission off the CMB as
discussed by the previous investigators. In this scenario, its high X-ray to
radio monochromatic luminosity ratio, compared to previously detected IC/CMB
X-ray jets at lower redshift, is a natural consequence of its high redshift.


title: A library of galaxy mergers

abstract:
  We have undertaken a large series of numerical simulations with the goal to
built a library of galaxy mergers (GALMER). Since the aim is to have more than
a thousand of realisations, each individual run is simplified, with a small
number of particules (24 000), but following the chemodynamical evolution, with
star formation and feedback. We illustrate in this short report some
preliminary results.


title: Cosmic microwave background snapshots: pre-WMAP and post-WMAP

abstract:
  Abbreviated: We highlight the remarkable evolution in the CMB power spectrum
over the past few years, and in the cosmological parameters for minimal
inflation models derived from it. Grand unified spectra (GUS) show pre-WMAP
optimal bandpowers are in good agreement with each other and with the one-year
WMAP results, which now dominate the L < 600 bands. GUS are used to determine
calibrations, peak/dip locations and heights, and damping parameters. These CMB
experiments significantly increased the case for accelerated expansion in the
early universe (the inflationary paradigm) and at the current epoch (dark
energy dominance) when they were combined with `prior' probabilities on the
parameters. A minimal inflation parameter set is applied in the same way to the
evolving data. Grid-based and and Monte Carlo Markov Chain methods are shown to
give similar values, highly stable over time and for different prior choices,
with the increasing precision best characterized by decreasing errors on
uncorrelated parameter eigenmodes. After marginalizing over the other cosmic
and experimental variables for a weak+LSS prior, the pre-WMAP data of Jan03 cf.
the post-WMAP data of Mar03 give Omega_{tot} =1.03^{+0.05}_{-0.04} cf.
1.02^{+0.04}_{-0.03}. Adding the flat prior, n_s =0.95^{+0.07}_{-0.04} cf.
0.97^{+0.02}_{-0.02}, with < 2\sigma evidence for a log variation of n_s. The
densities have concordance values. The dark energy pressure-to-density ratio is
not well constrained by our weak+LSS prior, but adding SN1 gives w_Q < -0.7. We
find \sigma_8 = 0.89^{+0.06}_{-0.07} cf. 0.86^{+0.04}_{-0.04}, implying a
sizable SZ effect; the high L power suggest \sigma_8 \sim 0.94^{+0.08}_{-0.16}
is needed to be SZ-compatible.


title: Status of the ANTARES Project

abstract:
  The ANTARES collaboration is constructing a neutrino telescope in the
Mediterranean Sea at a depth of 2400 metres, about 40 kilometres off the French
coast near Toulon. The detector will consist of 12 vertical strings anchored at
the sea bottom, each supporting 25 triplets of optical modules equipped with
photomultipliers, yielding sensitivity to neutrinos with energies above some 10
GeV. The effective detector area is roughly 0.1 square kilometres for neutrino
energies exceeding 10 TeV. The measurement of the Cherenkov light emitted by
muons produced in muon-neutrino charged-current interactions in water and
under-sea rock will permit the reconstruction of the neutrino direction with an
accuracy of better than 0.3 degrees at high energies. ANTARES will complement
the field of view of neutrino telescopes at the South Pole in the
low-background searches for point-sources of high-energy cosmic neutrinos and
will also be sensitive to neutrinos produced by WIMP annihilation in the Sun or
the Galactic centre.


title: Turbulence in Clusters of Galaxies and X-Ray Line Profiles

abstract:
  Large-scale bulk motions and hydrodynamic turbulence in the intergalactic gas
inside clusters of galaxies significantly broaden X-ray emission lines. For
lines of heavy ions (primarily helium-like and hydrogen-like iron ions), the
hydrodynamic broadening is significantly larger than the thermal broadening.
Since cluster of galaxies have a negligible optical depth for resonant
scattering in forbidden and intercombination lines of these ions, these lines
are not additionally broadened. At the same time, they are very intense, which
allows deviations of the spectrum from the Gaussian spectrum in the line wings
to be investigated. The line shape becomes an important indicator of bulk
hydrodynamic processes because the cryogenic detectors of new generation of
X-ray observatories will have a high energy resolution (from 5 eV for ASTRO-E2
to 1-2 eV for Constellation-X and XEUS). We use the spectral representation of
a Kolmogorov cascade in the inertial range to calculate the characteristic
shapes of X-ray lines. Significant deviations in the line profiles from the
Gaussian profile (shape asymmetry, additional peaks, sharp breaks in the
exponential tails) are expected for large-scale turbulence. The kinematic SZ
effect and the X-ray line profile carry different information about the
hydrodynamic velocity distribution in clusters of galaxies and complement each
other, allowing the redshift, the peculiar velocity of the cluster, and the
bulk velocity dispersion to be measured and separated


title: Results from the AST/RO Survey of the Galactic Center Region

abstract:
  We have used the Antarctic Submillimeter Telescope and Remote Observatory
(AST/RO), a 1.7m diameter single-dish submillimeter-wave telescope at the
geographic South Pole, to determine the physical state of gas in the Galactic
Center region and assess its stability. We present an analysis based on data
obtained as part of an ongoing AST/RO key project: the large-scale mapping of
the dominant cooling lines of the molecular interstellar medium in the Milky
Way. These data are released for general use.


title:
The Ultraluminous X-ray Source NGC 1313 X-2 (MS 0317.7-6647) and its
  Environment

abstract:
  We present new optical and {\it Chandra} observations of the field containing
the ultraluminous X-ray source NGC 1313 X-2. On an ESO 3.6 m image, the {\it
Chandra} error box embraces a $R=21.6$ point-like object and excludes a
previously proposed optical counterpart. The resulting X-ray/optical flux ratio
of NGC 1313 X-2 is $\sim 500$. The value of $f_X/f_{opt}$, the X-ray
variability history and the spectral distribution derived from a re-analysis of
the {\it ROSAT}, {\it ASCA} and {\it XMM} data indicate a luminous X-ray binary
in NGC 1313 as a likely explanation for NGC 1313 X-2. If the X-ray soft
component observed in the {\it XMM} EPIC spectrum originates from an accretion
disk, the inferred mass of the compact remnant is $\approx 100 M_\odot$, making
it an intermediate mass black hole. The derived optical luminosity ($L\approx
10^5 L_\odot$) is consistent with that of a $\approx 15-20 M_\odot$ companion.
The properties of the environment of NGC 1313 X-2 are briefly discussed.


title: A multi-particle model of the 3C 48 host

abstract:
  The first successful multi-particle model for the host of the well-known
quasi-stellar object (QSO) 3C 48 is reported. It shows that the morphology and
the stellar velocity field of the 3C 48 host can be reproduced by the merger of
two disk galaxies. The conditions of the interaction are similar to those used
for interpreting the appearance of the ''Antennae'' (NGC 4038/39) but seen from
a different viewing angle. The model supports the controversial hypothesis that
3C 48A is the second nucleus of a merging galaxy, and it suggests a simple
solution for the problem of the missing counter tidal tail.


title: Oxygen trends in the Galactic thin and thick disks

abstract:
  We present oxygen abundances for 72 F and G dwarf stars in the solar
neighbourhood. Using the kinematics of the stars we divide them into two
sub-samples with space velocities that are typical for the thick and thin
disks, respectively. The metallicities of the stars range from [Fe/H] = -0.9 to
+0.4 and we use the derived oxygen abundances of the stars to: (1) perform a
differential study of the oxygen trends in the thin and the thick disk; (2) to
follow the trend of oxygen in the thin disk to the highest metallicities. We
analyze the forbidden oxygen lines at 6300 {\AA} and 6363 {\AA} as well as the
(NLTE afflicted) triplet lines around 7774 {\AA}. For the forbidden line at
6300 A we have spectra of very high S/N (>400) and resolution (R=215 000). This
has enabled a very accurate modeling of the oxygen line and the blending Ni
lines. The high internal accuracy in our determination of the oxygen abundances
from this line is reflected in the very tight trends we find for oxygen
relative to iron........


title: The manifold spectra and morphologies of EROs

abstract:
  Deep VLT optical spectroscopy, HST+ACS (GOODS) imaging and VLA observations
are used to unveil the nature of a complete sample of 47 EROs with R-Ks>5 and
Ks<20. The spectroscopic redshift completeness is 62%. Morphological
classification was derived for each ERO through visual inspection and surface
brightness profile fitting. Three main ERO morphological types are found: E/S0
galaxies (30-37%), spiral-like (24-46%) and irregular systems (17-39%). The
only ERO detected in the radio is likely to host an obscured AGN. The average
radio luminosity of the star-forming EROs undetected in the radio implies star
formation rates of the order of 33 Msun yr^-1. The colors, redshifts and masses
of the E/S0 galaxy subsample imply a minimum formation redshift z_f \sim 2.
With this z_f there is enough time to have old and massive stellar spheroids
already assembled at z \sim 1. We verify that the R-Ks vs. J-Ks color diagram
is efficient in segregating old and dusty-star-forming EROs.


title:
Angular Momentum Transfer in Star-Discs Encounters: The Case of Low-Mass
  Discs

abstract:
  A prerequisite for the formation of stars and planetary systems is that
angular momentum is transported in some way from the inner regions of the
accretion disc. Tidal effects may play an important part in this angular
momentum transport. Here the angular momentum transfer in an star-disc
encounter is investigated numerically for a variety of encounter parameters in
the case of low mass discs. Although good agreement is found with analytical
results for the entire disc, the loss {\it inside} the disc can be up to an
order of magnitude higher than previously assumed. The differences in angular
momentum transport by secondaries on a hyperbolic, parabolic and elliptical
path are shown, and it is found that a succession of distant encounters might
be equally, if not more, successful in removing angular momentum than single
close encounter.


title: X-Ray Sources Overdensity Around the 3C 295 Galaxy Cluster

abstract:
  We present a statistical analysis of the Chandra observation of the source
field around the 3C 295 galaxy cluster ($z=0.46$). The logN-logS of this field
is in good agreement with that computed for the Chandra Deep Field South in
this work and in previous ones. Nevertheless, the logN-logS computed separately
for the four ACIS-I chips reveals that there is a significant excess of sources
to the North-North East and a void to the South of the central cluster. Such an
asymmetric distribution is confirmed by the two-dimensional Kolmogorov-Smirnov
test, which excludes ($P \sim 3%$) a uniform distribution. In addition, a
strong spatial correlation emerges from the study of the angular correlation
function of the field: the angular correlation function is above that expected
for X-ray sources on a few arcmin scales. In synthesis, the present analysis
may indicate a filament of the large scale structure of the Universe toward 3C
295. This kind of studies may open-up a new way to map (with high efficiency)
high-density peaks of large scale structures at high-z.


title: Cosmological models in the nonsymmetric Kaluza-Klein Theory

abstract:
  We consider a dynamics of Higgs' field in the framework of cosmological
models involving the scalar field from Nonsymmetric Kaluza-Klein (Jordan-Thiry)
Theory. The field plays here a role of a quintessence field. We consider phase
transition in cosmological models of the second and of the first order due to
evolution of Higgs' field. We developed inflationary models including
calculation of an amount of inflation. We match some cosmological models,
calculating a Hubble parameter and an age of the Universe.


title: Discovery of Blue Hook Stars in the Massive Globular Cluster M54

abstract:
  We present BV photometry centered on the globular cluster M54 (NGC 6715). The
color-magnitude diagram clearly shows a blue horizontal branch extending
anomalously beyond the zero age horizontal branch theoretical models. These
kinds of horizontal branch stars (also called ``blue hook'' stars), which go
beyond the lower limit of the envelope mass of canonical horizontal branch hot
stars, have so far been known to exist in only a few globular clusters: NGC
2808, Omega Centauri (NGC 5139), NGC 6273, and NGC 6388. Those clusters, like
M54, are among the most luminous in our Galaxy, indicating a possible
correlation between the existence of these types of horizontal branch stars and
the total mass of the cluster. A gap in the observed horizontal branch of M54
around T(eff)= 27000 K could be interpreted within the late helium flash
theoretical scenario, a possible explanation for the origin of those stars.


title:
Magnetic Driving of Relativistic Outflows in Active Galactic Nuclei. I.
  Interpretation of Parsec-Scale Accelerations

abstract:
  There is growing evidence that relativistic jets in active galactic nuclei
undergo extended (parsec-scale) acceleration. We argue that, contrary to some
suggestions in the literature, this acceleration cannot be purely hydrodynamic.
Using exact semianalytic solutions of the relativistic MHD equations, we
demonstrate that the parsec-scale acceleration to relativistic speeds inferred
in sources like the radio galaxy NGC 6251 and the quasar 3C 345 can be
attributed to magnetic driving. Additional observational implications of this
model will be explored in future papers in this series.


title: Gamma-Ray Pulsars: Modeling and Searches

abstract:
  Using a likelihood analysis (updated since McLaughlin & Cordes 2000) and
EGRET detections, upper limits and diffuse background measurements, we find a
best-fit luminosity law for the gamma-ray pulsar population. We find that
roughly 30 of the 170 unidentified EGRET sources are likely to be pulsars. This
is roughly twice the number of known radio pulsars which are plausibly
associated with unidentified EGRET sources. We predict that AGILE will detect
roughly 70 pulsars as point sources, including 12 which will be able to be
detected in blind periodicity searches. GLAST should detect roughly 1200
pulsars (including only 200 currently known radio pulsars), 210 of which will
be able to be detected in blind searches. We discuss methods of searching for
pulsars in gamma-ray data and present results from our searches for gamma-ray
periodicities from new radio pulsars associated with unidentified EGRET
sources.


title: "Circles in the Sky" in twisted cylinders

abstract:
  It is shown here how prior estimates on the local shape of the universe can
be used to reduce, to a small region, the full parameter space for the search
of circles in the sky. This is the first step towards the development of
efficient estrategies to look for these matched circles in order to detect a
possible nontrivial topology of our Universe. It is shown how to calculate the
unique point, in the parameter space, representing a pair of matched circles
corresponding to a given isometry $g$ (and its inverse). As a consequence, (i)
given some fine estimates of the covering group $\Gamma$ of the spatial section
of our universe, it is possible to confine, in a very effective way, the region
of the parameter space in which to perform the searches for matched circles,
and reciprocally (ii) once identified such pairs of matched circles, one could
determine with greater precision the topology of our Universe and our location
within it.


title:
Long term stability and dynamical environment of the PSR 1257+12
  planetary system

abstract:
  We study the long-term dynamics of the PSR 1257+12 planetary system. Using
the recently determined accurate initial condition by Konacki & Wolszczan
(2003) who derived the orbital inclinations and the absolute masses of the
planets B and C, we investigate the system stability by long-term, 1Gyr direct
integrations. No secular changes of the semi-major axes eccentricities and
inclinations appear during such an interval. This stable behavior is confirmed
with the fast indicator MEGNO. The analysis of the orbital stability in the
neighborhood of the nominal initial condition reveals that the PSR 1257+12
system is localized in a wide stable region of the phase space but close to a
few weak 2 and 3-body mean motion resonances. The long term stability is
additionally confirmed by a negligible exchange of the Angular Momentum Deficit
between the innermost planet A and the pair of the outer planets B and C. An
important feature of the system that helps sustain the stability is the secular
apsidal resonance (SAR) between the planets B and C with the center of
libration about 180deg. We find useful limits on the elements of the innermost
planet A which are otherwise unconstrained by the observations. We also perform
a preliminary study of the short-term dynamics of massless particles in the
system.


title: Multicomponent stellar winds of He chemically peculiar stars

abstract:
  We calculate multicomponent stellar wind models with inclusion of a helium
component applicable to He-rich and He-poor stars. We show that helium does not
decouple from the stellar wind of He-rich stars due to its coupling to hydrogen
and its ionized state. For He-poor stars helium may decouple from the stellar
wind, however this effect is not able to explain the chemical peculiarity of
these stars. We conclude that the explanation of chemical peculiarity of these
stars based purely on helium or hydrogen decoupling from the stellar wind is
unlikely.


title:
The Optical Gravitational Lensing Experiment. Optical Monitoring of the
  Gravitationally Lensed Quasar HE1104-1805 in 1997-2002

abstract:
  We present results of the long term monitoring of the gravitationally lensed
quasar HE1104-1805. The photometric data were collected between August 1997 and
January 2002 as a subproject of the OGLE survey.
  We determine the time delay in the light curves of images A and B of
HE1104-1805 to be equal to 157+/-21 days with the variability in the image B
light curve leading variability of the image A. The result is in excellent
agreement with the earlier determination by Ofek and Maoz.
  OGLE photometry of HE1104-1805 is available to the astronomical community
from the OGLE Internet archive.


title: Nuclear reactions in the Sun after SNO and KamLAND

abstract:
  In this brief review we discuss the possibility of studying the solar
interior by means of neutrinos, in the light of the enormous progress of
neutrino physics in the last few years. The temperature near the solar center
can be extracted from Boron neutrino experiments as: $ T= (1.57 \pm 0.01) 10^7
K$. The energy production rate in the Sun from pp chain and CNO cycle, as
deduced from neutrino measurements, agrees with the observed solar luminosity
to about twenty per cent. Progress in extracting astrophysical information from
solar neutrinos requires improvement in the measurements of $^3He+$ \\$^4He \to
^7Be+\gamma$ and $p+^{14}N \to ^{15}O+ \gamma$.


title: C_l interpolation for cosmological parameter estimation

abstract:
  I will briefly present my work on cosmological parameters estimation.
Classical methods for parameters estimation involve the exploration of the
parameter space on a precalculated grid of cosmological models. Here we try to
estimate the cosmological parameters by using a minimization method associated
with the interpolation of the C_l spectrum. We first use a simple
multidimensional linear interpolation, and show the flaws of this method. We
then introduce a new interpolation method, based on a physical description of
the location of the acoustic peaks in the power spectrum


title: Morphology of Mock SDSS Catalogues

abstract:
  We measure the geometry, topology and morphology of the superclusters in mock
SDSS catalogues prepared by Cole et al.(1998). The mock catalogues refer to
$\tau$CDM and $\L$CDM {\em flat} cosmological models and are populated by
galaxies so that these act as biased tracers of mass, conforming with the
correlation function measured using APM catalogue. We compute the Minkowski
Functionals (MFs) for the cosmic density fields using SURFGEN (Sheth et
al.2003) and use the available 10 realizations of $\tau$CDM to study the effect
of cosmic variance in estimation of MFs and Shapefinders, which we find to be
extremely well constrained statistics. Although all the mock catalogues of
galaxies have the same two-point correlation function and similar clustering
amplitude, the global MFs due to $\tau$CDM show systematically lower amplitude
compared to those due to $\L$CDM; an indirect, but detectable effect due to
nonzero, higher order correlation functions. The characteristic thickness (T),
breadth (B) and length (L) of the superclusters are measured using the
available 10 realizations of $\tau$CDM. While T$\le$B and T, B$\in$[1,17]
h$^{-1}$Mpc, we find the top 10 superclusters to be as long as 90 h$^{-1}$Mpc,
with the longest superclusters identified at percolation to be rare objects
with their length as large as 150 h$^{-1}$Mpc. The $\tau$CDM superclusters are
found to be significantly longer than those in $\L$CDM. Thickness (T), breadth
(B), planarity (P) and mass/volume$-$weighted planarity and filamentarity of
the superclusters are found to be useful to compare the two models (abridged).


title: Properties of galaxy dark matter halos from weak lensing

abstract:
  We present the results of a study of the average mass profile around galaxies
using weak gravitational lensing. We use 45.5 deg^2 of R_C band imaging data
from the Red-Sequence Cluster Survey (RCS) and define a sample of 1.2\times
10^5 lenses with 19.5<R_C<21, and a sample of 1.5\times 10^6 background
galaxies with 21.5<R<24. We constrain the power law scaling relations between
the $B$-band luminosity and the mass and size of the halo, and find that the
results are in excellent agreement with observed luminosity-line-width
relations. Under the assumption that the luminosity does not evolve with
redshift, the best fit NFW model yields a mass M_{200}=(8.8\pm0.7)\times
10^{11} h^{-1} Msun and a scale radius r_s=16.7^{+3.7}_{-3.0} h^{-1} kpc for a
galaxy with a fiducial luminosity of \lumstar. The latter result is in
excellent agreement with predictions from numerical simulations for a halo of
this mass. We also observe a signficant anisotropy of the lensing signal around
the lenses, implying that the halos are flattened and aligned with the light
distribution. We find an average projected) halo ellipticity of <e_{\rm
halo}>=0.20^{+0.04}_{-0.05}, in fair agreement with results from numerical
simulations of CDM. Alternative theories of gravity (without dark matter)
predict an isotropic lensing signal, which is excluded with 99.5% confidence.
Hence, our results provide strong support for the existence of dark matter.


title: Quantum Effects during Inflation

abstract:
  The expansion of spacetime alters the energy-time uncertainty principle,
allowing virtual particles to persist longer than in flat space. For a given
expansion the effect is largest for massless particles which are not
conformally invariant. For a given particle type the effect is largest for
inflation. I exhibit these two principles in the context of massless fermions
which are Yukawa-coupled to massless scalars. I also review the many related
examples which have been studied recently.


title: Did Massive Primordial Stars Preenrich the Lyman Alpha Forest?

abstract:
  We examine the dynamical evolution and statistical properties of the
supernova ejecta of massive primordial stars in a cosmological framework to
determine whether this first population of stars could have enriched the
universe to the levels and dispersions seen by the most recent observations of
the Lyman-Alpha forest. We evolve a lambda CDM model in a 1 Mpc^3 volume to a
redshift of z = 15 and add ``bubbles'' of metal corresponding to the supernova
ejecta of the first generation of massive stars in all dark matter halos with
masses greater than 5 times 10^5 solar masses. These initial conditions are
then evolved to z = 3 and the distribution and levels of metals are compared to
observations. In the absence of further star formation the primordial metal is
initially contained in halos and filaments. Photoevaporation of metal-enriched
gas due to the metagalactic ultraviolet background radiation at the epoch of
reionization (z ~ 6) causes a sharp increase of the metal volume filling
factor. At z = 3, ~ 2.5% of the simulation volume (approx. 20% of the total gas
mass) is filled with gas enriched above a metallicity of 10^-4 Z_solar, and
less than 0.6% of the volume is enriched above a metallicity of 10^-3 Z_solar.
This suggests that, even with the most optimistic prescription for placement of
primordial supernova and the amount of metals produced by each supernova, this
population of stars cannot entirely be responsible for the enrichment of the
Lyman-$\alpha$ forest to the levels and dispersions seen by current
observations unless we have severely underestimated the duration of the Pop III
epoch. However, comparison to observations show that Pop III supernovae can be
significant contributors to the very low overdensity Lyman-Alpha forest.


title: Detection of OH and wide HI absorption toward B0218+357

abstract:
  We present deep GMRT OH and WSRT HI absorption spectra of the $z = 0.6846$
gravitational lens toward B0218+357. Both the 1665 MHz and 1667 MHz OH lines
are clearly detected for the first time while a new wide absorption component
was detected (at low significance) in the HI spectrum; the OH spectra yielded
an OH column density of $N_{OH} = 2.3 \times 10^{15}$ cm^{-2}. The ratio of
1667 and 1665 MHz equivalent widths is $\sim 1.8$ while the redshift of peak OH
absorption is $z = 0.68468 \pm 0.000008$ for both lines; this redshift agrees
with that obtained from the HI line. The velocity spread (between nulls) of the
HI absorption is $\sim 140$ km/s, while that of both OH lines is $\sim 100$
km/s; the HI and OH spectra are broadly similar in that they each have two
principal narrow components and a wide absorption trough. We argue that the
wide absorption is likely to arise from source components in the Einstein ring
and derive a rotation velocity of $\sim 150$ km/s at a distance of 1.5 kpc from
the centre of the $z \sim 0.6846$ galaxy.


title: Cluster Heating by Viscous Dissipation of Sound Waves

abstract:
  We simulate the effects of viscous dissipation of waves that are generated by
AGN activity in clusters of galaxies. We demonstrate that the amount of viscous
heating associated with the dissipation of these waves can offset radiative
cooling rates in cooling flow clusters of galaxies. This heating mechanism
leads to spatially distributed and approximately symmetrical dissipation. The
heating waves reach a given distance from the cluster center on a timescale
shorter than the cooling time. This means that this heating mechanism has the
potential of quenching cooling flows in a quasi-stable fashion. Moreover, the
heating is gentle as no strong shocks are present in the simulations. We first
investigated whether a single continuous episode of AGN activity can lead to
adequate dissipation to balance cooling rates. These simulations demonstrated
that, whereas secondary waves generated by the interaction of the rising bubble
with the intracluster medium are clearly present, viscous heating associated
with the dissipation of these waves is insufficient to balance radiative
cooling. It is only when the central source is intermittent that the viscous
dissipation of waves associated with subsequent episodes of activity can offset
cooling. This suggests that the ripples observed in the Perseus cluster can be
interpreted as being due to the AGN duty cycle, i.e., they trace AGN activity
history. The simulations were performed using the PPM adaptive mesh refinement
code FLASH in two dimensions.


title: The temperature of the WNM in the Milky Way

abstract:
  We report high spectral resolution Australia Telescope Compact Array HI 21 cm
observations resulting in the detection of the warm neutral medium (WNM) of the
Galaxy in absorption against two extragalactic radio sources, PKS 1814-637 and
PKS 0407-658. The two lines of sight were selected on the basis of the
simplicity of their absorption profiles and the strength of the background
sources; the high velocity resolution of the spectra then enabled us to
estimate the kinetic temperatures of the absorbing gas by fitting multiple
Gaussians to the absorption profiles. Four separate WNM components were
detected toward the two sources, with peak optical depths $\tau_{max} = (1.0
\pm 0.08) \times 10^{-2}$, $(1.4 \pm 0.2) \times 10^{-3}$, $(2.2 \pm 0.5)
\times 10^{-3}$ and $(3.4 \pm 0.5) \times 10^{-3}$ and kinetic temperatures
$T_{k} = 3127 \pm 300$ K, $3694 \pm 1595$ K, $3500 \pm 1354$ K and $2165 \pm
608$ K respectively. All four components were thus found to have temperatures
in the thermally unstable range $500 < T_{k} < 5000$ K; this suggests that
thermal equilibrium has not been reached throughout the WNM.


title: The VLA Galactic Plane Survey (VGPS)

abstract:
  The VLA Galactic Plane Survey (VGPS) consists of measurements of the 21cm HI
line and 1420 MHz continuum at 1' angular resolution over much of the first
quadrant of Galactic longitude within a few degrees of the Galactic plane. In
combination with similar surveys of the fourth longitude quadrant and the outer
Galaxy made with other instruments, the VGPS will provide comprehensive data on
the interstellar medium in most of the regions of active star formation in the
Galaxy. This paper describes the parameters of the VGPS, reports on its status,
and discusses some early scientific results from the survey.


title: Supernova Science at Spallation Neutron Sources

abstract:
  New facilities to measure neutrino-nucleus cross sections, such as those
possible in conjunction with spallation neutron sources, could provide an
experimental foundation for the many neutrino-nucleus weak interaction rates
needed in supernova models. This would enable more realistic supernova models
and provide a greatly improved ability to understand the physics fundamental to
supernovae by comparison of these models with detailed observations. Charged-
and neutral-current neutrino interactions on nuclei in the stellar core play a
central role in supernova dynamics and nucleosynthesis as well as being
important for supernova neutrino detection. Measurements of these reactions on
judiciously chosen targets would provide an invaluable test of the complex
theoretical models used to compute the large number of neutrino-nucleus cross
sections that are needed.


title: Constraining the variation of fundamental constants using 18cm OH lines

abstract:
  We describe a new technique to estimate variations in the fundamental
constants using 18cm OH absorption lines. This has the advantage that all lines
arise in the same species, allowing a clean comparison between the measured
redshifts. In conjunction with one additional transition (for example, an
HCO$^+$ line), it is possible to simultaneously measure changes in $\alpha$,
$g_p$ and $y \equiv m_e/m_p$. At present, only the 1665 MHz and 1667 MHz lines
have been detected at cosmological distances; we use these line redshifts in
conjunction with those of HI 21cm and mm-wave molecular absorption in a
gravitational lens at $z\sim 0.68$ to constrain changes in the above three
parameters over the redshift range $0 < z \lesssim 0.68$. While the constraints
are relatively weak ($\lesssim$ 1 part in $10^3$), this is the first
simultaneous constraint on the variation of all three parameters. We also
demonstrate that either one (or more) of $\alpha$, $g_p$ and $y$ must vary with
cosmological time or there must be systematic velocity offsets between the OH,
HCO$^+$ and HI absorbing clouds.


title:
The use of OH "main" lines to constrain the variation of fundamental
  constants

abstract:
  We describe a new technique to measure variations in the fundamental
parameters $\alpha$ and $y \equiv m_e/m_p$, using the sum of the frequencies of
cm-wave OH ``main'' lines. The technique is $\sim$ three orders of magnitude
more sensitive than that of Chengalur & Kanekar (2003), which utilised only the
four 18cm OH lines. The increase in sensitivity stems from the use of OH
``main'' lines arising from different rotational states, instead of the
frequency difference between lines from the same state. We also show that
redshifts of the main OH 18cm and 6cm lines can be combined with the redshift
of an HCO$^+$ transition to measure any evolution in $\alpha$ and $y$. Both
18cm main lines and a number of HCO$^+$ lines have already been detected in
absorption in four cosmologically distant systems; the detection of the main
6cm OH line in any of these systems would thus be sufficient to simultaneously
constrain changes in $\alpha$ and $y$ between the absorption redshift and
today.


title: The Nature of the Local Group

abstract:
  The Local Group provides an interesting and representative sample of galaxies
in the rest of the Universe. The high accuracy with which many problems can be
addressed in Local Group galaxies is of paramount importance for understanding
galaxy formation and evolution. This contribution presents a short review of
overall Local Group properties followed by short discussions of five topics in
which the study of Local Group members provides particularly significant
information. These topics are only examples of the usefulness and potential of
Local Group research. The five selected topics are the formation of the Milky
Way, galaxy destruction and tidal streams, detailed galactic chemical
evolution, star formation history determination, and low surface brightness
extended structures.


title: Spatially resolved spectrum of the Vela PWN

abstract:
  A series of 13 Chandra observations provided the deepest images of the Vela
PWN yet available. In addition to the fine structure of the inner PWN features,
a much larger and fainter asymmetric X-ray nebula emerges in the summed images.
The shape of this outer PWN is similar to that of the radio PWN. We also
present the spectral map of the Vela PWN that reveals a shell of soft emission
surrounding the inner PWN and an extended region of harder emission south-west
of the pulsar. This may indicate that the outer jet is supplying particles to
this region.


title:
Constraints on SN Ia Progenitors and ICM enrichment from field and
  cluster SN rates

abstract:
  The iron mass in galaxy clusters is about 6 times larger than could have been
produced by core-collapse SNe, assuming the stars in cluster galaxies formed
with a standard IMF. Type-Ia SNe have been proposed as the alternative dominant
iron source. We use our HST measurements of the cluster SN-Ia rate at high
redshift to study the cluster iron enrichment scenario. The measurements can
constrain the star-formation epoch and the SN-Ia progenitor models via the mean
delay time between the formation of a stellar population and the explosion of
some of its members as SNe-Ia. The low observed rate of cluster SNe-Ia at z~1
pushes back the star-formation epoch in clusters to z>2, and implies a short
delay time. We also show a related analysis for high-z field SNe which implies,
under some conditions, a long SN-Ia delay time. Thus, cluster enrichment by
core-collapse SNe from a top-heavy IMF may remain the only viable option.


title: Highly Ionized Gas Surrounding High Velocity Cloud Complex C

abstract:
  We present Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope
observations of high, intermediate, and low ion absorption in high-velocity
cloud Complex C along the lines of sight toward five active galaxies. Our
purpose is to investigate the idea that Complex C is surrounded by an envelope
of highly ionized material, arising from the interaction between the cloud and
a hot surrounding medium. We measure column densities of high-velocity high ion
absorption, and compare the kinematics of low, intermediate, and high
ionization gas along the five sight lines. We find that in all five cases, the
H I and O VI high-velocity components are centered within 20 km/s of one
another, with an average displacement of <v(O VI)-v(H I)>=3+-12 km/s. In those
directions where the H I emission extends to more negative velocities (the
so-called high-velocity ridge), so does the O VI absorption. We compare our
high ion column density ratios to the predictions of various models, adjusted
to account for both recent updates to the solar elemental abundances, and for
the relative elemental abundance ratios in Complex C. Our observed ratios are
inconsistent with collisional ionization equilibrium at one kinetic
temperature. Photoionization by the extragalactic background is ruled out as
the source of the high ions, since the path lengths required would make Complex
C unreasonably large. We consider the most likely origin for the highly ionized
high-velocity gas to be at the conductive or turbulent interfaces between the
neutral/warm ionized components of Complex C and a surrounding hot medium. The
presence of interfaces on the surface of HVCs provides indirect evidence for
the existence of a hot medium in which the HVCs are immersed.


title:
Damped Lyman-alpha Absorbers in Cosmological SPH Simulations: the
  "metallicity problem"

abstract:
  We study the distribution of star formation rate (SFR) and metallicity of
damped Lyman-alpha absorbers (DLAs) using cosmological smoothed particle
hydrodynamics (SPH) simulations of the Lambda cold dark matter model. Our
simulations include a phenomenological model for feedback by galactic winds
which allows us to examine the effect of galactic outflows on the distribution
of SFR and metallicity of DLAs. For models with strong galactic winds, we
obtain good agreement with recent observations with respect to total neutral
hydrogen mass density, N_HI column-density distribution, abundance of DLAs, and
for the distribution of SFR in DLAs. However, we also find that the median
metallicity of simulated DLAs is higher than the values typically observed by
nearly an order of magnitude. This discrepancy with observations could be due
to shortcomings in the treatment of the supernova feedback or the multiphase
structure of the gas in our current simulations. Recent observations by Wolfe
et al. (2003a,b) seem to point to the same problem; i.e. the observed DLA
metallicities are much lower than those expected from the (either observed or
simulated) DLA star formation rates, a puzzle that has been known as the
``missing metals'' problem for the globally averaged quantities.


title:
The evolution of gravitationally unstable protoplanetary disks:
  fragmentation and possible giant planet formation

abstract:
  We carry out a large set of very high resolution, three dimensional smoothed
particle hydrodynamics (SPH) simulations describing the evolution of
gravitationally unstable gaseous protoplanetary disks. We consider a broad
range of initial disk parameters. Disk masses out to 20 AU range from 0.075 to
0.125 $M_{\odot}$, roughly consistent with the high-end of the mass
distribution inferred for disks around T Tauri stars. The initial disks span
minimum $Q$ parameters between 0.8 and 2, with most models being around $\sim
1.4$. The disks are evolved assuming either a locally isothermal equation of
state or an adiabatic equation of state with varying $\gamma$. When
overdensities above a specific threshold appear as a result of gravitational
instability in a locally isothermal calculation, the equation of state is
switched to adiabatic to account for the increased optical depth. We show that
when a disk has a minimum $Q$ parameter less than 1.4 strong trailing spiral
instabilities, typically three or four armed modes, form and grow until
fragmentation occurs along the arms after about 5 mean disk orbital times. The
resulting clumps contract quickly to densities several orders of magnitude
higher than the initial disk density, and the densest of them survive even
under adiabatic conditions. These clumps are stable to tidal disruption and
merge quickly, leaving 2-3 protoplanets on fairly eccentric orbits (the mean
eccentricity being around 0.2) with masses between 0.7 and more than $7
M_{Jup}$, well in agreement with those of detected extrasolar planets.after
$\sim 10^3$ years. Fragmentation is not strongly dependent on whether the disk
starts from a marginally unstable state or gradually achieves it, as shown by a
test where the disk gradually achieves the critical $Q$ by growing in mass.


title:
Powerful obscured AGN among X-ray hard, optically-dim serendipitous
  Chandra sources

abstract:
  We present a small sample of Chandra X-ray sources selected from the fields
of ACIS observations which probe fluxes around the break in the hard band
source counts. The targets of these fields include 9 nearby galaxy clusters, 1
distant cluster and 2 powerful radio galaxy fields. The follow-up of this
serendipitous sample was biased towards X-ray hard and optically-dim sources
mostly not seen on the Digitized Sky Survey; for these, we present X-ray
fluxes, optical and near-infrared photometry leading to 51 photometric
redshifts in all and 18 independently measured spectroscopic redshifts. Few
sources are associated with the target fields themselves. Fifty-six of 58
sources imaged in the K-band are detected at K<~20 with K_median=18, and of
these, 38 have hard X-ray count ratios and 24 of these are significantly hard
with most of the counts emerging about 2 keV. We find that almost all are AGN
hosted in massive early-type host galaxies with a photometric redshift
distribution peaking at z~1. Two type 2 quasars with intrinsic X-ray luminosity
L>~10^{45} erg/s, Fe K_alpha emission lines and absorbing column density
nH>10^{23} cm^{-2} -- and nH>~10^{24} cm^{-2} in one case -- are discussed in
detail; the sample contains at least 12 potential type 2 quasars in all. We
discuss various detection strategies for type 2 quasars and calculate their
inferred space density. This combines and extends a number of results from
subsamples already published by us.


title:
CCD Photometry of the Globular Cluster omega Centauri. II. Stellar
  Populations and Age-Metallicity Relation

abstract:
  We present wide-field and high-precision BV and Ca & Stromgren by photometry
of omega Centauri, which represents one of the most extensive photometric
surveys to date for this cluster. The member stars of omega Cen are well
discriminated from foreground Galactic field stars in the hk [=(Ca-b)-(b-y)]
vs. b-y diagram. The resulting "cleaned" color-magnitude diagram (CMD) has
allowed us to obtain an accurate distribution of the red horizontal branch (HB)
and the asymptotic giant branch stars. We confirm the presence of several red
giant branches (RGBs) with the most metal-rich sequence well separated from
other bluer metal-poor ones. Our population models suggest that four
populations with different metallicities can reproduce the observed nature of
the RGB. The HB distribution is also found to be consistent with the multiple
stellar populations of the RGB. From our population models, we propose that the
most metal-rich population is about 4 Gyr younger than the dominant metal-poor
population, indicating that omega Cen was enriched over this timescale. We
identify, for the first time, a continuous and slanting RGB bump in the CMD of
omega Cen, which is due to the metallicity spread amongst the RGB stars. Our
photometry also reveals a significant population of blue straggler stars. The
discovery of several populations and the internal age-metallicity relation of
omega Cen provides good evidence that omega Cen was once part of a more massive
system that merged with the Milky Way, as the Sagittarius dwarf galaxy is in
the process of doing at the present time.


title: Discovery of a Massive Protostar near IRAS 18507+0121

abstract:
  We have observed the massive star forming region, IRAS 18507+0121, at
millimeter wavelengths in 3 mm continuum emission and H13CO+(J=1-0) and
SiO(v=0, J=2-1) line emission, and at near-infrared wavelengths between 1.2 and
2.1 microns. Two compact molecular cores are detected: one north and one south
separated by about 40". The northern molecular core contains a newly
discovered, deeply embedded, B2 protostar surrounded by several hundred solar
masses of warm gas and dust, G34.4+0.23 MM. Based on the presence of warm dust
emission and the lack of detection at near-infrared wavelengths, we suggest
that G34.4+0.23 MM may represent the relatively rare discovery of a massive
protostar (e.g. analogous to a low-mass "Class 0" protostar). The southern
molecular core is associated with a near-infrared cluster of young stars and an
ultracompact (UC) HII region, G34.4+0.23, with a central B0.5 star. The
fraction of near-infrared stars with excess infrared emission indicative of
circumstellar material is greater than 50% which suggests an upper limit on the
age of the IRAS 18507+0121 star forming region of 3 Myrs.


title:
Neutrino Properties from Measurements using Astrophysical and
  Terrestrial Sources

abstract:
  The current knowledge of neutrino properties has been derived from
measurements performed with both astrophysical and terrestrial sources.
Observations of neutrino flavor change have been made with neutrinos generated
in the solar core, through cosmic ray interactions in the atmosphere and in
nuclear reactors. A summary is presented of the current knowledge of neutrino
properties and a description is provided for future measurements that could
provide more complete information on neutrino properties.


title:
Cosmological Mestel Disks and the Rossby Vortex Instability: The Origin
  of Supermassive Black Holes

abstract:
  A scenario is put forth for the formation of supermassive black holes at the
centers of galaxies. It depends upon the formation of a Mestel disk with a flat
rotation curve, where the mass is proportional to r and thickness to 1/r. Such
disks should form from the collapse of uniformly rotating, isolated, gaseous
clouds, either proto-galactic, galaxy-mass damped Lyman alpha clouds or the gas
that survives galaxy mergers. We propose that in any case the disk will be
unstable to the Rossby vortex instability (RVI). This instability grows from
any large, steep pressure gradient in an optically thick disk. Such pressure
gradients either occur adjacent to compact objects or could be triggered by
individual supernovae in and around the disk. Upon excitation, the RVI
transports angular momentum far more efficiently than the turbulence of a
viscosity-based Shakura-Sunyaev disk. The critical column density condition in
a L* Mestel disk predicts that the black hole mass is ~ 10^8 Msolar and is also
proportional to the 1/4 power of the velocity dispersion, in accordance with
observations.


title: Low-Energy X-ray Emission from Young Isolated Neutron Stars

abstract:
  A young neutron star with large spin-down power is expected to be closely
surrounded by an e+/- pair plasma maintained by the conversion of gamma-rays
associated with the star's polar-cap and/or outer-gap accelerators.
Cyclotron-resonance scattering by the e- and e+ within several radii of such
neutron stars prevents direct observations of thermal X-rays from the stellar
surface. Estimates are presented for the parameters of the Planck-like
X-radiation which ultimately diffuses out through this region. Comparisons with
observations, especially of apparent blackbody emission areas as a function of
neutron star age, support the proposition that we are learning about a neutron
star's magnetosphere rather than about its surface from observations of young
neutron star thermal X-rays.


title:
The K band galaxy luminosity functions of three massive high redshift
  clusters of galaxies

abstract:
  K band observations of the galaxy populations of three high redshift
(z=0.8-1.0), X-ray selected, massive clusters are presented. The observations
reach a depth of K=21.5, corresponding to K*+3.5 mag. The evolution of the
galaxy properties are discussed in terms of their K band luminosity functions
and the K band Hubble diagram of brightest cluster galaxies.
  The bulk of the galaxy luminosities, as characterised by the parameter K*
from the Schechter (1976) function, are found to be consistent with passive
evolution with a redshift of formation of z_f~1.5-2. This is consistent with
observations of other high redshift clusters, but may be in disagreement with
galaxies in the field at similar redshifts. A good match to the shape of the
Coma cluster luminosity function is found by simply dimming the high redshift
luminosity function by an amount consistent with passive evolution. The
evolution of the cumulative fraction of K band light as a function of
luminosity shows no evidence of merger activity in the brighter galaxies.
  The evolution of the brightest cluster galaxies (BCGs) is tested by their K
band Hubble diagram and by the fraction of K band cluster light in the BCGs.
The evolution observed is consistent with recent previous observations although
the scatter in the Hubble diagram allows for a range of evolutionary histories.
The fraction of cluster light contained in the BCGs is not smaller than that in
Coma, suggesting that they are already very massive with no need to hypothesise
significant mergers in their futures.


title:
Distances, Metallicities, and Ages of Dwarf Elliptical Galaxies in the
  Virgo Cluster from Surface Brightness Fluctuations

abstract:
  We have employed FORS1/2+VLT to acquire deep B and R CCD images of 16 dwarf
elliptical galaxies in the direction of the Virgo cluster. For each dwarf we
measure the R-band surface brightness fluctuation (SBF) magnitude \bar{m}_R and
the (B-R) colour in a number of fields at different galactocentric distances.
  From the field-to-field variation of the two quantities we determine the SBF
distance by means of the (B-R)-\bar{M}_R relation. The derived distances of the
dwarfs are ranging from 14.9-21.3Mpc, with a mean 1sigma uncertainty of 1.4Mpc,
confirming that there is considerable depth in the distance distribution of
early-type cluster members. For IC3388 our SBF distance of 17.0+-1.5Mpc is in
good agreement with the Harris et al. result based on HST observations and the
tip magnitude of the red giant branch. Combining our results with existing
distances for giant Virgo ellipticals we identify two major galaxy
concentrations: a broad primary clump around 15.8Mpc and a narrow secondary
clump around 18.5Mpc. An adaptive kernel analysis finds the two concentrations
to be significant at the 99% and 89% levels. While the near-side clump of Virgo
early-type galaxies can be associated to the subcluster centered on M87, the
second clump is believed to be mainly due to the backside infalling group of
galaxies around M86. The ages and metallicities of the dE stellar populations
are estimated by combining the observed (B-R) colours with Worthey's stellar
population synthesis models. It appears that the Virgo dEs cover a wider range
in metallicity than Fornax cluster dEs. The derived metallicities place the
Virgo dEs on the extension of the [Fe/H]-M_V relation defined by the Local
Group dEs. The data further suggest an age range from genuinly old stellar
systems like IC3019 to intermediate-age dwarfs like NGC4431.


title: On magnetic field generation in Kolmogorov turbulence

abstract:
  We analyze the initial, kinematic stage of magnetic field evolution in an
isotropic and homogeneous turbulent conducting fluid with a rough velocity
field, v(l) ~ l^alpha, alpha<1. We propose that in the limit of small magnetic
Prandtl number, i.e. when ohmic resistivity is much larger than viscosity, the
smaller the roughness exponent, alpha, the larger the magnetic Reynolds number
that is needed to excite magnetic fluctuations. This implies that numerical or
experimental investigations of magnetohydrodynamic turbulence with small
Prandtl numbers need to achieve extremely high resolution in order to describe
magnetic phenomena adequately.


title: New insights on the thermal dust from the far-infrared to the centimeter

abstract:
  We present a compilation of PRONAOS-based results concerning the temperature
dependence of the dust submillimeter spectral index, including data from
Galactic cirrus, star-forming regions, dust associated to a young stellar
object, and a spiral galaxy. We observe large variations of the spectral index
(from 0.8 to 2.4) in a wide range of temperatures (11 to 80 K). These spectral
index variations follow a hyperbolic-shaped function of the temperature, high
spectral indices (1.6-2.4) being observed in cold regions (11-20 K) while low
indices (0.8-1.6) are observed in warm regions (35-80 K). Three distinct
effects may play a role in this temperature dependence: one is that the grain
sizes change in dense environments, another is that the chemical composition of
the grains is not the same in different environments, a third one is that there
is an intrinsic dependence of the dust spectral index on the temperature due to
quantum processes. This last effect is backed up by laboratory measurements and
could be the dominant one.
  We also briefly present a joint analysis of WMAP dust data together with
COBE/DIRBE and COBE/FIRAS data.


title: Effects of Dust Scattering in Expanding Spherical Nebulae

abstract:
  The mean intensity of planetary nebulae with an expanding atmosphere is
modeled by considering dusty and dust-free atmospheres. The bulk matter density
is determined from the adopted velocity field through the equation of
continuity. The gas is assumed to consist of hydrogen and helium and the
gas-to-dust mass ratio is taken to be $3\times10^{-4}$. The Rayleigh phase
function is employed for atomic scattering while the full Mie theory of
scattering is incorporated for determining the dust scattering and absorption
cross-section as well as the phase function for the angular distribution of
photons after scattering. It is shown that in a dust free atmosphere, the mean
intensity increases with the increase in the expansion velocity that makes the
medium diluted. The mean intensity profile changes significantly when dust
scattering is incorporated. The increase in forward scattering of photons by
the dust particles yields into an increase in the mean intensity as compared to
that without dust. The mean intensity increases as the particle size is
increased. Thus it is shown that both the expansion of the medium and the
presence of dust play important role in determining the mean intensity of a
planetary nebulae.


title: XDR Chemistry in the Circumnuclear Disk of NGC 1068

abstract:
  We have studied the feedback influence that the central engine of the Seyfert
2 galaxy NGC 1068 may have on the chemistry of the 200 pc circumnuclear gas
disk (CND). With this purpose, we have conducted a
multi-species/multi-transition survey of molecular gas in the CND of NGC 1068
using the IRAM 30m telescope. Abundances of several molecular species have been
estimated, including HCN, CN, CS, HCO+, SiO and HOC+. We report on the
detection of significant SiO emission in this galaxy, as well as on the first
extragalactic detection of the active radical HOC+. We conclude that the
chemistry of the molecular gas reservoir in the CND can be best explained in
the framework of X-rays Dominated Regions (XDR) models.


title: An X-ray absorption analysis of the high-velocity system in NGC 1275

abstract:
  We present an X-ray absorption analysis of the high-velocity system (HVS) in
NGC 1275 using results from a deep 200 ks Chandra observation. We are able to
describe the morphology of the HVS in more detail than ever before. We present
an HST image for comparison, and note close correspondence between the deepest
X-ray absorption and the optical absorption. A column density map of the HVS
shows an average column density NH of 1x10^21 cm^-2 with a range from ~5x10^20
to 5x10^21 cm^-2. From the NH map we calculate a total mass for the absorbing
gas in the HVS of (1.32+-0.05)x10^9 solar masses at solar abundance. 75 per
cent of the absorbing mass is contained in the four regions of deepest
absorption. We examine temperature maps produced by spectral fitting and find
no direct evidence for shocked gas in the HVS. Using deprojection methods and
the depth of the observed absorption, we are able to put a lower limit on the
distance of the HVS from the nucleus of 57 kpc, showing that the HVS is quite
separate from the body of NGC 1275.


title:
Fluctuation Analysis of the Far-Infrared Background - Information from
  the Confusion

abstract:
  We are investigating to what extent one can use a P(D) analysis to extract
number counts of unclustered sources from maps of the far infrared background.
Currently available such maps, and those expected to emerge in near future are
dominated by confusion noise due to poor resolution. We simulate background
maps with an underlying two slope model for N(S) and we find that in an
experiment of FIRBACK type we can extract the high flux slope with an error of
few percent while other parameters are not so well constrained. We find,
however, that in a SIRTF type experiment all parameters of this N(S) model can
be extracted with errors of only few percent.


title:
FLY. A parallel tree N-body code for cosmological simulations. Reference
  Guide

abstract:
  FLY is a parallel treecode which makes heavy use of the one-sided
communication paradigm to handle the management of the tree structure. In its
public version the code implements the equations for cosmological evolution,
and can be run for different cosmological models.
  This reference guide describes the actual implementation of the algorithms of
the public version of FLY, and suggests how to modify them to implement other
types of equations (for instance the Newtonian ones)


title: CMB map-making and power spectrum estimation

abstract:
  CMB data analysis is in general done through two main steps : map-making of
the time data streams and power spectrum extraction from the maps. The latter
basically consists in the separation between the variance of the CMB and that
of the noise in the map. Noise must therefore be deeply understood so that the
estimation of CMB variance (the power spectrum) is unbiased. I present in this
article general techniques to make maps from time streams and to extract the
power spectrum from them. We will see that exact, maximum likelihood solutions
are in general too slow and hard to deal with to be used in modern experiments
such as Archeops and should be replaced by approximate, iterative or
Monte-Carlo approaches that lead to similar precision.


title: Archeops results

abstract:
  \Archeops is a balloon--borne instrument dedicated to measuring cosmic
microwave background (CMB) temperature anisotropies at high angular resolution
($\sim$ 12 arcmin.) over a large fraction (30%) of the sky in the
(sub)millimetre domain (from 143 to 545 GHz). We describe the results obtained
during the last flight: the \Archeops estimate of the CMB angular power
spectrum linking for the first time \Cobe scales and the first acoustic peak,
consequences in terms of cosmological parementers favouring a flat-$\Lambda$
Universe. We also present the first measurement of galactic dust polarization
and accurate maps of the galactic plane diffuse (sub) millimetre emisson.


title:
Smoothed Particle Magnetohydrodynamics I. Algorithms and tests in one
  dimension

abstract:
  In this paper we show how the Smoothed Particle Hydrodynamics (SPH) equations
for ideal magnetohydrodynamics (MHD) can be written in conservation form with
the positivity of the dissipation guaranteed. We call the resulting algorithm
Smoothed Particle Magnetohydrodynamics (SPMHD). The equations appear to be
accurate, robust and easy to apply and do not suffer from the instabilities
known to exist previously in formulations of the SPMHD equations. In addition
we formulate our MHD equations such that errors associated with non-zero
divergence of the magnetic field are naturally propagated by the flow and
should therefore remain small.
  In this and a companion paper (Price and Monaghan 2003b) we present a wide
range of numerical tests in one dimension to show that the algorithm gives very
good results for one dimensional flows in both adiabatic and isothermal MHD.
For the one dimensional tests the field structure is either two or three
dimensional.
  The algorithm has many astrophysical applications and is particularly suited
to star formation problems.


title:
Smoothed Particle Magnetohydrodynamics II. Variational principles and
  variable smoothing length terms

abstract:
  In this paper we show how a Lagrangian variational principle can be used to
derive the SPMHD (smoothed particle magnetohydrodynamics) equations for ideal
MHD. We also consider the effect of a variable smoothing length in the SPH
kernels after which we demonstrate by numerical tests that the consistent
treatment of terms relating to the gradient of the smoothing length in the
SPMHD equations significantly improves the accuracy of the algorithm. Our
results complement those obtained in a companion paper (Price and Monaghan
2003a, paper I) for non ideal MHD where artificial dissipative terms were
included to handle shocks.


title:
When Is a Bulge Not a Bulge? Inner Disks Masquerading as Bulges in NGC
  2787 and NGC 3945

abstract:
  We present a detailed morphological, photometric, and kinematic analysis of
two barred S0 galaxies with large, luminous inner disks inside their bars. We
show that these structures, in addition to being geometrically disk-like, have
exponential profiles (scale lengths $\sim$ 300--500 pc) distinct from the
central, non-exponential bulges. We also find them to be kinematically
disk-like. The inner disk in NGC 2787 has a luminosity roughly twice that of
the bulge; but in NGC 3945, the inner disk is almost ten times more luminous
than the bulge, which itself is extremely small (half-light radius $\approx$
100 pc, in a galaxy with an outer ring of radius $\approx$ 14 kpc) and only
$\sim$ 5% of the total luminosity -- a bulge/total ratio much more typical of
an Sc galaxy. We estimate that at least 20% of (barred) S0 galaxies may have
similar structures, which means that their bulge/disk ratios may be
significantly overestimated. These inner disks dominate the central light of
their galaxies; they are at least an order of magnitude larger than typical
``nuclear disks'' found in ellipticals and early-type spirals. Consequently,
they must affect the dynamics of the bars in which they reside.


title: Calibration of the Spectrometer aboard the INTEGRAL satellite

abstract:
  SPI, the Spectrometer on board the ESA INTEGRAL satellite, to be launched in
October 2002, will study the gamma-ray sky in the 20 keV to 8 MeV energy band
with a spectral resolution of 2 keV for photons of 1 MeV, thanks to its 19
germanium detectors spanning an active area of 500 cm2. A coded mask imaging
technique provides a 2 deg angular resolution. The 16 deg field of view is
defined by an active BGO veto shield, furthermore used for background
rejection. In April 2001 the flight model of SPI underwent a one-month
calibration campaign at CEA in Bruy\`eres le Ch\^atel using low intensity
radioactive sources and the CEA accelerator for homogeneity measurements and
high intensity radioactive sources for imaging performance measurements. After
integration of all scientific payloads (the spectrometer SPI, the imager IBIS
and the monitors JEM-X and OMC) on the INTEGRAL satellite, a cross-calibration
campaign has been performed at the ESA center in Noordwijk. A set of sources
has been placed in the field of view of the different instruments in order to
compare their performances and determine their mutual influence. Some of those
sources had already been used in Bruy\`eres during the SPI standalone test. For
the lowest energy band calibration an X-ray generator has been used. We report
on the scientific goals of this calibration activity, and present the
measurements performed as well as some preliminary results.


title: SPI/INTEGRAL in-flight performance

abstract:
  The SPI instrument has been launched on-board the INTEGRAL observatory on
October 17, 2002. SPI is a spectrometer devoted to the sky observation in the
20 keV-8 MeV energy range using 19 germanium detectors. The performance of the
cryogenic system is nominal and allows to cool the 19 kg of germanium down to
85 K with a comfortable margin. The energy resolution of the whole camera is
2.5 keV at 1.1 MeV. This resolution degrades with time due to particle
irradiation in space. We show that the annealing process allows the recovery of
the initial performance. The anticoincidence shield works as expected, with a
low threshold at 75 keV, reducing the GeD background by a factor of 20. The
digital front-end electronics system allows the perfect alignement in time of
all the signals as well as the optimisation of the dead time (12%). We
demonstrate that SPI is able to map regions as complex as the galactic plane.
The obtained spectrum of the Crab nebula validates the present version of our
response matrix. The 3 $\sigma$ sensitivity of the instrument at 1 MeV is 8
10$^{-7}$ph$\cdot$cm$^{-2}\cdot$s$^{-1}\cdot$keV$^{-1}$ for the continuum and 3
10$^{-5}$ph$\cdot$cm$^{-2}\cdot$s$^{-1}$ for narrow lines.


title:
X-ray properties of galaxy clusters and groups from a cosmological
  hydrodynamical simulation

abstract:
  We present results on the X-ray properties of clusters and groups of
galaxies, extracted from a large hydrodynamical simulation. We used the GADGET
code to simulate a LambdaCDM model within a box of 192 Mpc/h on a side, with
480^3 dark matter particles and as many gas particles. The simulation includes
radiative cooling, star formation and supernova feedback. The simulated M-T
relation is consistent with observations once we mimic the procedure for mass
estimates applied to real clusters. Also, with the adopted choices of
Omega_m=0.3 and sigma_8=0.8 the resulting XTF agrees with observational
determinations. The L-T relation also agrees with observations for clusters
with T>2 keV, with no change of slope at the scale of groups. The entropy in
central cluster regions is higher than predicted by gravitational heating
alone, the excess being almost the same for clusters and groups. The simulated
clusters appear to have suffered some overcooling, with f*~0.2, thus about
twice as large as the value observed. Interestingly, temperature profiles are
found to steadily increase toward cluster centers. They decrease in the outer
regions, much like observational data do at r>0.2r_vir, while not showing an
isothermal regime followed by a smooth temperature decline in the innermost
regions.


title: Multifrequency Radiation of Extragalactic Large-Scale Jets

abstract:
  Large-scale extragalactic jets, observed to extend from a few to a few
hundred kiloparsecs from active galactic nuclei, are now studied over many
decades in frequency of electromagnetic spectrum, from radio until (possibly)
TeV gamma rays. For hundreds of known radio jets, only about 25 are observed at
optical frequencies. Most of them are relatively short and faint, with only a
few exceptions, like 3C 273 or M 87, allowing for detailed spectroscopic and
morphological studies. Somewhat surprisingly, the large-scale jets can be very
prominent in X-rays. Up to now, about 25 jets were detected within the 1 - 10
keV energy range, although the nature of this emission is still under debate.
In general, both optical and X-ray jet observations present serious problems
for standard radiation models for the considered objects. Recent TeV
observations of M 87 suggest the possibility of generating large photon fluxes
at these high energies by its extended jet.
  In this paper we summarize information about multiwavelength emission of the
large-scale jets, and we point out several modifications of the standard jet
radiation models (connected with relativistic bulk velocities, jet radial
stratification and particle energization all the way along the jet), which can
possibly explain some of the mentioned puzzling observations. We also comment
on gamma-ray emission of the discussed objects.