title: The Highest Dynamical Frequency in the Inner Region of an Accretion Disk

abstract:
  In the inner regions of accretion disks around compact objects, the orbital
frequency of the gas deviates from the local Keplerian value. For
long-wavelength modes in this region, the radial epicyclic frequency kappa is
higher than the azimuthal frequency Omega. This has significant implications
for models of the twin kHz QPOs observed in many neutron-star sources that
traditionally identify the frequencies of the two kHz QPOs with dynamical
frequencies in the accretion disk. The recognition that the highest frequency
in the transition or boundary region of the disk is actually the epicyclic
frequency also modifies significantly the constraints imposed by the
observation of high-frequency QPOs on the mass and radius of the compact
objects.


title:
Rubidium and lead abundances in giant stars of the globular clusters M
  13 and NGC 6752

abstract:
  We present measurements of the neutron-capture elements Rb and Pb in five
giant stars of the globular cluster NGC 6752 and Pb measurements in four giants
of the globular cluster M 13. The abundances were derived by comparing
synthetic spectra with high resolution, high signal-to-noise ratio spectra
obtained using HDS on the Subaru telescope and MIKE on the Magellan telescope.
The program stars span the range of the O-Al abundance variation. In NGC 6752,
the mean abundances are [Rb/Fe] = -0.17 +/- 0.06 (sigma = 0.14), [Rb/Zr] =
-0.12 +/- 0.06 (sigma = 0.13), and [Pb/Fe] = -0.17 +/- 0.04 (sigma = 0.08). In
M 13 the mean abundance is [Pb/Fe] = -0.28 +/- 0.03 (sigma = 0.06). Within the
measurement uncertainties, we find no evidence for a star-to-star variation for
either Rb or Pb within these clusters. None of the abundance ratios [Rb/Fe],
[Rb/Zr], or [Pb/Fe] are correlated with the Al abundance. NGC 6752 may have
slightly lower abundances of [Rb/Fe] and [Rb/Zr] compared to the small sample
of field stars at the same metallicity. For M 13 and NGC 6752 the Pb abundances
are in accord with predictions from a Galactic chemical evolution model. If
metal-poor intermediate-mass asymptotic giant branch stars did produce the
globular cluster abundance anomalies, then such stars do not synthesize
significant quantities of Rb or Pb. Alternatively, if such stars do synthesize
large amounts of Rb or Pb, then they are not responsible for the abundance
anomalies seen in globular clusters.


title:
Clues to AGN Growth from Optically Variable Objects in the Hubble Ultra
  Deep Field

abstract:
  We present a photometric search for objects with point-source components that
are optically variable on timescales of weeks--months in the Hubble Ultra Deep
Field (HUDF) to i'(AB)=28.0 mag. The data are split into four sub-stacks of
approximately equal exposure times. Objects exhibiting the signature of optical
variability are selected by studying the photometric error distribution between
the four different epochs, and selecting 622 candidates as 3.0 sigma outliers
from the original catalog of 4644 objects. Of these, 45 are visually confirmed
as free of contamination from close neighbors or various types of image
defects. Four lie within the positional error boxes of Chandra X-ray sources,
and two of these are spectroscopically confirmed AGN. The photometric redshift
distribution of the selected variable sample is compared to that of field
galaxies, and we find that a constant fraction of ~1% of all field objects show
variability over the range of 0.1<z<4.5. Combined with other recent HUDF
results, as well as those of recent state-of-the-art numerical simulations, we
discuss a potential link between the hierarchical merging of galaxies and the
growth of AGN.


title: On Oscillating Dark Energy

abstract:
  Distance-redshift data can impose strong constraints on dark energy models
even when the equation of state is oscillatory. Despite the double integral
dependence of the distance on the equation of state, precision measurement of
the distance-redshift relation for z=0-2 is more incisive than the linear
growth factor, CMB last scattering surface distance, and the age of the
universe in distinguishing oscillatory behavior from an average behavior. While
oscillating models might help solve the coincidence problem (since acceleration
occurs periodically), next generation observations will strongly constrain such
possibilities.


title:
On measuring the covariance matrix of the nonlinear power spectrum from
  simulations

abstract:
  We show how to estimate the covariance of the power spectrum of a
statistically homogeneous and isotropic density field from a single periodic
simulation, by applying a set of weightings to the density field, and by
measuring the scatter in power spectra between different weightings. We
recommend a specific set of 52 weightings containing only combinations of
fundamental modes, constructed to yield a minimum variance estimate of the
covariance of power. Numerical tests reveal that at nonlinear scales the
variance of power estimated by the weightings method substantially exceeds that
estimated from a simple ensemble method. We argue that the discrepancy is
caused by beat-coupling, in which products of closely spaced Fourier modes
couple by nonlinear gravitational growth to the beat mode between them.
Beat-coupling appears whenever nonlinear power is measured from Fourier modes
with a finite spread of wavevector, and is therefore present in the weightings
method but not the ensemble method. Beat-coupling inevitably affects real
galaxy surveys, whose Fourier modes have finite width. Surprisingly, the
beat-coupling contribution dominates the covariance of power at nonlinear
scales, so that, counter-intuitively, it is expected that the covariance of
nonlinear power in galaxy surveys is dominated not by small scale structure,
but rather by beat-coupling to the largest scales of the survey.


title: A Virgo high-resolution Halpha kinematical survey : II. The Atlas

abstract:
  A catalog of ionized gas velocity fields for a sample of 30 spiral and
irregular galaxies of the Virgo cluster has been obtained by using
three-dimensional optical data. The aim of this survey is to study the
influence of high density environments on the gaseous kinematics of local
cluster galaxies. Observations of the Halpha line by means of Fabry-Perot
interferometry have been performed at the Canada-France-Hawaii, ESO 3.6m,
Observatoire de Haute-Provence 1.93m and Observatoire du mont Megantic
telescopes at angular and spectral samplings from 0.4" to 1.6" and 7 to 16
km/s. A recently developed, automatic and adaptive spatial binning technique is
used to reach a nearly constant signal-to-noise ratio (S/N) over the whole
field-of-view, allowing to keep a high spatial resolution in high S/N regions
and extend the detection of signal in low S/N regions. This paper is part of a
series and presents the integrated emission-line and velocity maps of the
galaxies. Both Halpha morphologies and kinematics exhibit signs of
perturbations in the form of e.g. external filaments, inner and nuclear spiral-
and ring-like structures, inner kinematical twists, kinematical decoupling of a
nuclear spiral, streaming motions along spiral arms and misalignment between
kinematical and photometric orientation axes.


title:
Information content of the non-linear power spectrum: the effect of
  beat-coupling to large scales

abstract:
  We measure the covariance of the non-linear matter power spectrum from N-body
simulations using two methods. In the first case, the covariance of power is
estimated from the scatter over many random realizations of the density field.
In the second, we use a novel technique to measure the covariance matrix from
each simulation individually by re-weighting the density field with a carefully
chosen set of functions. The two methods agree at linear scales, but
unexpectedly they disagree substantially at increasingly non-linear scales.
Moreover, the covariance of non-linear power measured using the re-weightings
method changes with box size. The numerical results are consistent with an
explanation given in a companion paper, which argues that the cause of the
discrepancy is beat-coupling, in which products of Fourier modes separated by a
small wavevector couple by gravitational growth to the large-scale beat mode
between them. We calculate the information content of the non-linear power
spectrum (about the amplitude of the initial, linear power spectrum) using both
methods and confirm the result of a previous paper, that at translinear scales
the power spectrum contains little information over and above that in the
linear power spectrum, but that there is a marked increase in information at
non-linear scales. We suggest that, in real galaxy surveys, the covariance of
power at non-linear scales is likely to be dominated by beat-coupling to the
largest scales of the survey and that, as a result, only part of the
information potentially available at non-linear scales is actually measurable
from real galaxy surveys.


title: The proximity of Mercury's spin to Cassini state 1

abstract:
  In determining Mercury's core structure from its rotational properties, the
value of the normalized moment of inertia, $C/MR^2$, from the location of
Cassini 1 is crucial. If Mercury's spin axis occupies Cassini state 1, its
position defines the location of the state. The spin might be displaced from
the Cassini state if the spin is unable to follow the changes in the state
position induced by the variations in the orbital parameters and the geometry
of the solar system. The spin axis is expected to follow the Cassini state for
orbit variations with time scales long compared to the 1000 year precession
period of the spin about the Cassini state because the solid angle swept out by
the spin axis as it precesses is an adiabatic invariant. Short period
variations in the orbital elements of small amplitude should cause
displacements that are commensurate with the amplitudes of the short period
terms. By following simultaneously the spin position and the Cassini state
position during long time scale orbital variations over past 3 million years
(Quinn {\it et al.}, 1991) and short time scale variations from JPL Ephemeris
DE 408 (Standish, 2005) we show that the spin axis will remain within one
arcsec of the Cassini state after it is brought there by dissipative torques.
We thus expect Mercury's spin to occupy Cassini state 1 well within the
uncertainties for both radar and spacecraft measurements, with correspondingly
tight constraints on $C/MR^2$.


title: The Onset of Planet Formation in Brown Dwarf Disks

abstract:
  The onset of planet formation in protoplanetary disks is marked by the growth
and crystallization of sub-micron-sized dust grains accompanied by dust
settling toward the disk mid-plane. Here we present infrared spectra of disks
around brown dwarfs and brown dwarf candidates. We show that all three
processes occur in such cool disks in a way similar or identical to that in
disks around low- and intermediate-mass stars. These results indicate that the
onset of planet formation extends to disks around brown dwarfs, suggesting that
planet formation is a robust process occurring in most young circumstellar
disks.


title: Early-Time Observations of the GRB 050319 Optical Transient

abstract:
  We present the unfiltered ROTSE-III light curve of the optical transient
associated with GRB 050319 beginning 4 s after the cessation of gamma-ray
activity. We fit a power-law function to the data using the revised trigger
time given by Chincarini et al. (2005), and a smoothly broken power-law to the
data using the original trigger disseminated through the GCN notices. Including
the RAPTOR data from Wozniak et al. (2005), the best fit power-law indices are
alpha=-0.854 (+/- 0.014) for the single power-law and alpha_1=-0.364 (+/-
0.020), alpha_2= -0.881 (+/- 0.030), with a break at t_b = 418 (+/- 30) s for
the smoothly broken fit. We discuss the fit results with emphasis placed on the
importance of knowing the true start time of the optical transient for this
multi-peaked burst. As Swift continues to provide prompt GRB locations, it
becomes more important to answer the question, "when does the afterglow begin"
to correctly interpret the light curves.


title:
First Detection of PAHs and Warm Molecular Hydrogen in Tidal Dwarf
  Galaxies

abstract:
  We observed two faint tidal dwarf galaxies (TDGs), NGC 5291N and NGC 5291 S
with the Infrared Spectrograph on the Spitzer Space Telescope. We detect strong
polycyclic aromatic hydrocarbon (PAH) emission, which match models of groups of
\~100 carbon atoms with an equal mixture of neutral and ionized PAHs. The TDGs
have a dominant warm ~140 K dust component in marked contrast to the cooler,
40-60 K dust found in starburst galaxies. For the first time we detect the
low-J rotational lines from molecular hydrogen. Adopting LTE there is ~10^5
solar masses of ~400 K gas, which is <0.1 % of the cold gas mass. The
combination of one-third solar metallicity with a recent, <5 million year,
epsiode of star formation is reflected in the S and Ne ratios. The excitation
is higher than typical values for starburst galaxies and similar to that found
in BCDs. Using the Infared Array Camera we identify an additional 13 PAH-rich
candidate TDGs. These sources occupy a distinct region of IRAC color space with
[3.6] - [4.5] < 0.4 and [4.5] - [8.0] > 3.2. NGC 5291 N and S have stellar
masses of (1.5 and 3.0) 10^8 solar masses, which is comparable to BCDs. This
system appears to be a remarkable TDG nursery.


title: Tracing Galaxy Assembly: Tadpole Galaxies in the Hubble Ultra Deep Field

abstract:
  In the Hubble Ultra Deep Field (HUDF) an abundance of galaxies is seen with a
knot at one end plus an extended tail, resembling a tadpole. These "tadpole
galaxies" appear dynamically unrelaxed--presumably in an early merging
state--where tidal interactions likely created the distorted knot-plus-tail
morphology. Here we systematically select tadpole galaxies from the HUDF and
study their properties as a function of their photometric redshifts. In a
companion HUDF variability study, Cohen et al. (2005) revealed a total of 45
variable objects believed to be Active Galactic Nuclei (AGN). Here we show that
this faint AGN sample has no overlap with the tadpole galaxy sample, as
predicted by theoretical work. The tadpole morphology--combined with the lack
of overlap with the variable objects--supports the idea that these galaxies are
in the process of an early-stage merger event, i.e., at a stage that likely
precedes the "turn-on" of any AGN component and the onset of any point-source
variability.


title:
Connecting Dense Gas Tracers of Star Formation in our Galaxy to High-z
  Star Formation

abstract:
  Observations have revealed prodigious amounts of star formation in starburst
galaxies as traced by dust and molecular emission, even at large redshifts.
Recent work shows that for both nearby spiral galaxies and distant starbursts,
the global star formation rate, as indicated by the infrared luminosity, has a
tight and almost linear correlation with the amount of dense gas as traced by
the luminosity of HCN. Our surveys of Galactic dense cores in HCN 1-0 emission
show that this correlation continues to a much smaller scale, with nearly the
same ratio of infrared luminosity to HCN luminosity found over 7-8 orders of
magnitude in L_IR, with a lower cutoff around 10^{4.5} L_sun of infrared
luminosity. The linear correlation suggests that we may understand distant star
formation in terms of the known properties of local star-forming regions. Both
the correlation and the luminosity cutoff can be explained if the basic unit of
star formation in galaxies is a dense core, similar to those studied in our
Galaxy.


title:
The dusty AGB star RS CrB: first mid-infrared interferometric
  observations with the Keck Telescopes

abstract:
  We report interferometric observations of the semi-regular variable star RS
CrB, a red giant with strong silicate emission features. The data were among
the first long baseline mid-infrared stellar fringes obtained between the Keck
telescopes, using parts of the new nulling beam combiner. The light was
dispersed by a low-resolution spectrometer, allowing simultaneous measurement
of the source visibility and intensity spectra from 8 to 12 microns. The
interferometric observations allow a non-ambiguous determination of the dust
shell spatial scale and relative flux contribution. Using a simple
spherically-symmetric model, in which a geometrically thin shell surrounds the
stellar photosphere, we find that ~30% to ~70% of the overall mid-infrared flux
- depending on the wavelength - originates from 7-8 stellar radii. The derived
shell opacity profile shows a broad peak around 11 microns (tau ~ 0.06),
characteristic of Mg-rich silicate dust particles.


title:
Mode Identification from Combination Frequency Amplitudes in ZZ Ceti
  Stars

abstract:
  The lightcurves of variable DA stars are usually multi-periodic and
non-sinusoidal, so that their Fourier transforms show peaks at eigenfrequencies
of the pulsation modes and at sums and differences of these frequencies. These
combination frequencies provide extra information about the pulsations, both
physical and geometrical, that is lost unless they are analyzed. Several
theories provide a context for this analysis by predicting combination
frequency amplitudes. In these theories, the combination frequencies arise from
nonlinear mixing of oscillation modes in the outer layers of the white dwarf,
so their analysis cannot yield direct information on the global structure of
the star as eigenmodes provide. However, their sensitivity to mode geometry
does make them a useful tool for identifying the spherical degree of the modes
that mix to produce them. In this paper, we analyze data from eight hot,
low-amplitude DAV white dwarfs and measure the amplitudes of combination
frequencies present. By comparing these amplitudes to the predictions of the
theory of Goldreich & Wu, we have verified that the theory is crudely
consistent with the measurements. We have also investigated to what extent the
combination frequencies can be used to measure the spherical degree (ell) of
the modes that produce them. We find that modes with ell > 2 are easily
identifiable as high ell based on their combination frequencies alone.
Distinguishing between ell=1 and 2 is also possible using harmonics. These
results will be useful for conducting seismological analysis of large ensembles
of ZZ Ceti stars, such as those being discovered using the Sloan Digital Sky
Survey. Because this method relies only on photometry at optical wavelengths,
it can be applied to faint stars using 4 m class telescopes.


title: AO Assisted Near-IR Spectroscopy of SVS 13 and its Jet

abstract:
  We present long-slit H- and K-band spectroscopy of the low-mass outflow
source SVS 13, obtained with the adaptive-optics assisted imager-spectrometer
NACO on the VLT. With a spatial resolution of < 0.25 arcsec and a pixel scale
of 0.027 arcsec we precisely establish the relative offsets of H2, [FeII], CO,
HI and NaI components from the source continuum. The H2 and [FeII] peaks are
clearly associated with the jet, while the CO, HI and NaI peaks are spatially
unresolved and coincident with the source, as is expected for emission
associated with accretion processes. The H2 profile along the slit is resolved
into multiple components, which increase in size though decrease in intensity
with distance from the source. This trend might be consistent with thermal
expansion of packets of gas ejected during periods of increased accretion
activity. Indeed, for the brightest component nearest the source, proper motion
measurements indicate a tangential velocity of 0.028 arcsec/year. It therefore
seems unlikely that this emission peak is associated with a stationary zone of
warm gas at the base of the jet. However, the same can not be said for the
[FeII] peak, for which we see no evidence for motion downwind, even though
radial velocity measurements indicate that the emission is associated with
higher jet velocities. We postulate that the [FeII] could be associated with a
collimation shock at the base of the jet.


title:
Revisiting the Infrared Spectra of Active Galactic Nuclei with a New
  Torus Emission Model

abstract:
  We describe improved modelling of the emission by dust in a toroidal--like
structure heated by a central illuminating source within Active Galactic Nuclei
(AGN). We chose a simple but realistic torus geometry, a flared disc, and a
dust grain distribution function including a full range of grain sizes. The
optical depth within the torus is computed in detail taking into account the
different sublimation temperatures of the silicate and graphite grains, which
solves previously reported inconsistencies in the silicate emission feature in
type-1 AGN. We exploit this model to study the spectral energy distributions
(SEDs) of 58 extragalactic (both type-1 and type-2) sources using archival
optical and infrared (IR) data. We find that both AGN and starburst
contributions are often required to reproduce the observed SEDs, although in a
few cases they are very well fitted by a pure AGN component. The AGN
contribution to the far-IR luminosity is found to be higher in type-1 sources,
with all the type-2 requiring a substantial contribution from a circum-nuclear
starburst. Our results appear in agreement with the AGN Unified Scheme, since
the distributions of key parameters of the torus models turn out to be
compatible for type-1 and type-2 AGN. Further support to the unification
concept comes from comparison with medium-resolution IR spectra of type-1 AGN
by the Spitzer observatory, showing evidence for a moderate silicate emission
around 10 \mums which our code reproduces. From our analysis we infer accretion
flows in the inner nucleus of local AGN characterized by high equatorial
optical depths ($A_V\simeq 100$), moderate sizes ($R_{max}<100 pc$) and very
high covering factors ($f\simeq 80$ per cent) on average.


title:
INTEGRAL and XMM-Newton observations of the X-ray pulsar IGR
  J16320-4751/AX J1631.9-4752

abstract:
  We report on observations of the X-ray pulsar IGR J16320-4751 (a.k.a. AX
J1631.9-4752) performed simultaneously with INTEGRAL and XMM-Newton. We refine
the source position and identify the most likely infrared counterpart. Our
simultaneous coverage allows us to confirm the presence of X-ray pulsations at
~1300 s, that we detect above 20 keV with INTEGRAL for the first time. The
pulse fraction is consistent with being constant with energy, which is
compatible with a model of polar accretion by a pulsar. We study the spectral
properties of IGR J16320-4751 during two major periods occurring during the
simultaneous coverage with both satellites, namely a flare and a non-flare
period. We detect the presence of a narrow 6.4 keV iron line in both periods.
The presence of such a feature is typical of supergiant wind accretors such as
Vela X-1 or GX 301-2. We inspect the spectral variations with respect to the
pulse phase during the non-flare period, and show that the pulse is solely due
to variations of the X-ray flux emitted by the source and not to variations of
the spectral parameters.
  Our results are therefore compatible with the source being a pulsar in a High
Mass X-ray Binary. We detect a soft excess appearing in the spectra as a
blackbody with a temperature of ~0.07 keV. We discuss the origin of the X-ray
emission in IGR J16320-4751: while the hard X-rays are likely the result of
Compton emission produced in the close vicinity of the pulsar, based on energy
argument we suggest that the soft excess is likely the emission by a
collisionally energised cloud in which the compact object is embedded.


title:
Nuclear astrophysical plasmas: ion distribution functions and fusion
  rates

abstract:
  This article illustrates how very small deviations from the Maxwellian
exponential tail, while leaving unchanged bulk quantities, can yield dramatic
effects on fusion reaction rates and discuss several mechanisms that can cause
such deviations.

categories: astro-ph cond-mat.stat-mech nucl-th physics.plasm-ph


title: Masses and Radii of Low-Mass Stars: Theory versus Observations

abstract:
  Eclipsing binaries with M-type components are still rare objects. Strong
observational biases have made that today only a few eclipsing binaries with
component masses below 0.6 Msun and well-determined fundamental properties are
known. However, even in these small numbers the detailed comparison of the
observed masses and radii with theoretical predictions has revealed large
disagreements. Current models seem to predict radii of stars in the 0.4-0.8
Msun range to be some 5-15% smaller than observed. Given the high accuracy of
the empirical measurements (a few percent in both mass and radius), these
differences are highly significant. I review all the observational evidence on
the properties of M-type stars and discuss a possible scenario based on stellar
activity to explain the observed discrepancies.


title:
The properties of isolated Main Galaxies in Sloan Digital Sky Survey
  Data Release 3 (SDSS DR3)

abstract:
  We have constructed a Main galaxy subsample with redshifts in the range
0.08<=z<=0.12 from SDSS Data Release 3 (SDSS DR3), and refer to this subsample
as "MGSU"(It contains 67777 galaxies). By cluster analysis, two isolated Main
galaxy samples are extracted from this subsample. It turns out that two
isolated Main galaxy samples identified at different radii have the same
properties. Additionally, we also find that early-type galaxies in isolated
Main galaxy samples are fewer than that in close double galaxy sample.


title: Binaries as Astrophysical Laboratories: Open Questions

abstract:
  Binary systems have long been recognized as the source of powerful
astrophysical diagnostics. Among the many applications of binary stars, they
have been used as probes of stellar structure and evolution (both of single and
binary stars) in a broad range of masses, evolutionary stages, and chemical
compositions, and as indicators of distance and time. With the numerous ongoing
photometric surveys and upcoming space astrometry and photometry missions, the
future of binaries looks bright. The various aspects of binaries as
astrophysically useful laboratories are reviewed here, with emphasis on the
currently open problems and research opportunities.


title: Molecular gas in QSO host galaxies

abstract:
  We present the results of a survey for CO line emission from a sample of
nearby QSO hosts taken from the Hamburg/ESO survey (HES) and the Veron-Cetty
and Veron quasar catalogue. From a total of 39 observed sources we clearly
detected 5 objects with >10sigma signals (HE 0108-4743, HE 0224-2834,
J035818.7-612407, HE 1029-1831, HE 2211-3903). Further 6 sources show marginal
detections on the 2sigma level.


title: The XMM-Newton Slew Survey: towards the XMMSL1 catalogue

abstract:
  The XMM-Newton satellite is the most sensitive X-ray observatory flown to
date due to the great collecting area of its mirrors coupled with the high
quantum efficiency of the EPIC detectors. It performs slewing manoeuvers
between observation targets tracking almost circular orbits through the
ecliptic poles due to the Sun constraint. Slews are made with the EPIC cameras
open and the other instruments closed, operating with the observing mode set to
the one of the previous pointed observation and the medium filter in place.
  Slew observations from the EPIC-pn camera in FF, eFF and LW modes provide
data, resulting in a maximum of 15 seconds of on-source time. These data can be
used to give a uniform survey of the X-ray sky, at great sensitivity in the
hard band compared with other X-ray all-sky surveys.


title: Unveiling the distribution of absorption in the AGN population

abstract:
  We use the very deep XMM-Newton observations in the CDF-S to measure the
distribution of absorption in the AGN population. We describe the Monte Carlo
method used to unveil the intrinsic properties of the AGN using their
multi-band X-ray colours. The measured distribution of AGN in z, L_X and N_H
space is compared with the distributions predicted by a number of XLFs and
absorption models. In contrast to other studies, we do not find any evidence
that the absorption distribution is dependent on redshift or intrinsic
luminosity.


title: Statistical Computations with AstroGrid and the Grid

abstract:
  We outline our first steps towards marrying two new and emerging
technologies; the Virtual Observatory (e.g, AstroGrid) and the computational
grid. We discuss the construction of VOTechBroker, which is a modular software
tool designed to abstract the tasks of submission and management of a large
number of computational jobs to a distributed computer system. The broker will
also interact with the AstroGrid workflow and MySpace environments. We present
our planned usage of the VOTechBroker in computing a huge number of n-point
correlation functions from the SDSS, as well as fitting over a million CMBfast
models to the WMAP data.


title: Energy-shifted lines in XMM-Newton spectra of Seyfert Galaxies

abstract:
  In the recent literature on AGNs it has been often reported that spectra of
Seyfert 1 Galaxies show resonant absorption lines of Fe K which are redshifted
from the rest frame position. Such lines are often found with marginal
significance but, if real, could potentially open up new avenues to study the
circumnuclear gas in the black hole environment. It is also extremely important
to take them into account in X-ray spectral analysis because of the influence
they have in the correct estimation of spectral parameters, Fe K alpha line in
primis. An XMM-Newton observation of Mrk 335 is reported here as a case study:
a narrow feature has been detected at 5.9 keV, i.e. with a redshift
corresponding to a velocity of v ~ 0.15c. Preliminary results on the
statistical significance of narrow absorption and emission lines in a sample of
PG QSOs observed by XMM-Newton are also included.


title: The LMC HII region N 214C and its peculiar nebular blob

abstract:
  We study the Large Magellanic Cloud HII region N 214C using imaging and
spectroscopy obtained at the ESO New Technology Telescope. On the basis of the
highest resolution images so far obtained of the OB association LH 110, we show
that the main exciting source of the HII region, Sk -71 51, is in fact a tight
cluster of massive stars consisting of at least 6 components in an area ~ 4"
wide. Spectroscopic observations allow us to revise the spectral type of the
main component (# 17) to O2 V ((f*)) + OB, a very rare, hot type. We also
classify several other stars associated with N 214C and study the extinction
and excitation characteristics of the HII region. Moreover, we obtain BVR
photometry and astrometry of 2365 stars and from the corresponding
color-magnitude diagram study the stellar content of N 214C and the surrounding
LH 110. Furthermore, we discover a striking compact blob of ionized gas in the
outer northern part of N 214C. A spherical structure of ~ 5" in radius (~ 1.3
pc), it is split into two lobes by absorbing dust running diametrically through
its center. We discuss the possible nature of this object.


title: Varying Constants

abstract:
  We review properties of theories for the variation of the gravitation and
fine structure 'constants'. We highlight some general features of the
cosmological models that exist in these theories with reference to recent
quasar data that are consistent with time-variation in the fine structure
'constant' since a redshift of 3.5. The behaviour of a simple class of
varying-alpha cosmologies is outlined in the light of all the observational
constraints.


title:
Turbulent Gas Flows in the Rosette and G216-2.5 Molecular Clouds:
  Assessing Turbulent Fragmentation Descriptions of Star Formation

abstract:
  The role of turbulent fragmentation in regulating the efficiency of star
formation in interstellar clouds is examined from new wide field imaging of
12CO and 13CO J=1-0 emission from the Rosette and G216-2.5 molecular clouds.
The Rosette molecular cloud is a typical star forming giant molecular cloud and
G215-2.5 is a massive molecular cloud with no OB stars and very little low mass
star formation. The properties of the turbulent gas flow are derived from the
set of eigenvectors and eigenimages generated by Principal Component Analysis
of the spectroscopic data cubes. While the two clouds represent quite divergent
states of star formation activity, the velocity structure functions for both
clouds are similar. The sonic scale, lambda_S, defined as the spatial scale at
which turbulent velocity fluctuations are equivalent to the local sound speed,
and the turbulent Mach number evaluated at 1 pc, M_{1pc}, are derived for an
ensemble of clouds including the Rosette and, G216-2.5 regions that span a
large range in star formation activity. We find no evidence for the positive
correlations between these quantities and the star formation efficiency, that
are predicted by turbulent fragmentation models. A correlation does exist
between the star formation efficiency and the sonic scale for a subset of
clouds with L_{FIR}/M(H_2) > 1 that are generating young stellar clusters.
Turbulent fragmentation must play a limited and non-exclusive role in
determining the yield of stellar masses within interstellar clouds.


title: The Tully-Fisher relation of distant field galaxies

abstract:
  We examine the evolution of the Tully-Fisher relation (TFR) using a sample of
89 field spirals, with 0.1 < z < 1, for which we have measured confident
rotation velocities (Vrot). By plotting the residuals from the local TFR versus
redshift, or alternatively fitting the TFR to our data in several redshift
bins, we find evidence that luminous spiral galaxies are increasingly offset
from the local TFR with redshift, reaching a brightening of -1.0+-0.5 mag, for
a given Vrot, by approximately z = 1. Since selection effects would generally
increase the fraction of intrinsically-bright galaxies at higher redshifts, we
argue that the observed evolution is probably an upper limit.
  Previous studies have used an observed correlation between the TFR residuals
and Vrot to argue that low mass galaxies have evolved significantly more than
those with higher mass. However, we demonstrate that such a correlation may
exist purely due to an intrinsic coupling between the Vrot scatter and TFR
residuals, acting in combination with the TFR scatter and restrictions on the
magnitude range of the data, and therefore it does not necessarily indicate a
physical difference in the evolution of galaxies with different Vrot.
  Finally, if we interpret the luminosity evolution derived from the TFR as due
to the evolution of the star formation rate (SFR) in these luminous spiral
galaxies, we find that SFR(z) is proportional to (1+z)^(1.7+-1.1), slower than
commonly derived for the overall field galaxy population. This suggests that
the rapid evolution in the SFR density of the universe observed since
approximately z = 1 is not driven by the evolution of the SFR in individual
bright spiral galaxies. (Abridged.)


title: Radiatively Driven Winds of OB Stars -- from Micro to Macro

abstract:
  We review basic physics of line-driven stellar winds of OB stars. We discuss
elementary processes due to which stellar winds are accelerated on a
microscopic level. We show how these microscopic processes may enable the
outflow and how they determine wind properties on a macroscopic level. We
discuss shortcomings of present wind theories and future wind model
improvements.


title:
Identification of four RXTE Slew Survey sources with nearby luminous
  active galactic nuclei

abstract:
  Based on RXTE scans and observations with the SWIFT/XRT telescope and
INTEGRAL observatory, we report the identification of four X-ray sources
discovered during the RXTE Slew Survey of the |b|>10deg sky with nearby (z ~
0.017-0.098) luminous (log L_2-10keV ~ 42.7-44 erg/s) active galactic nuclei.
Two of the objects exhibit heavily intrinsically absorbed X-ray spectra
(NHL~10^23 cm^-2).


title:
Searching for Sharp Surface Brightness Discontinuities: a Systematic
  Study of Cold Fronts in Galaxy Clusters

abstract:
  We perform a systematic search of cold fronts in a sample of 62 clusters
observed with XMM-Newton with redshift ranging from 0.01 to 0.3. We detect one
or more cold fronts in 21 (34%) of our objects. A large fraction (87.5%) of
nearby clusters 0.01 < z < 0.04 host a cold front while only 20% of the distant
clusters, mostly merging clusters, do so. The absence of sharp surface
brightness discontinuites in distant cool cores is most likely a consequence of
the insufficent spatial resolution of our images. Some nearby cool core
clusters show a dislocation between the surface brightness and the pressure
peak. This implies that the cool central gas is displaced from the bottom of
the gravitational potential well and likely sloshing.


title: Evolution of rotating stars at very low metallicity

abstract:
  At very low metallicity, the effects of differential rotation have a more
important impact on the evolution of stars than at high metallicity. Rotational
mixing leads to the production of great quantities of helium and of primary
$^{14}$N by massive stars. Rotation induces important mass loss and allows
stars to locally strongly enrich the interstellar medium in CNO elements. Stars
formed from interstellar clouds enriched by the winds of fast rotating massive
stars would present surface abundances similar to those of C-rich extremely
metal-poor stars. C-rich stars can also be formed by mass accretion in a binary
system where the primary would be a fast rotating intermediate mass star in the
early-AGB phase. Fast rotation may also lead to the formation of collapsars
even at very low metallicity and make the most massive stars avoid the pair
instability.


title:
Reconstruction of an Inductive Velocity Field Vector from Doppler
  Motions and a Pair of Solar Vector Magnetograms

abstract:
  We outline a general methodology to infer the inductive velocity field vector
in solar active regions. For the first time, both the field-aligned and the
cross-field velocity components are reconstructed. The cross-field velocity
solution accounts for the changes of the vertical magnetic field seen between a
pair of successive active-region vector magnetograms via the ideal induction
equation. The field-aligned velocity is obtained using the Doppler velocity and
the calculated cross-field velocity. Solving the ideal induction equation in
vector magnetograms measured at a given altitude in the solar atmosphere is an
under-determined problem. In response, our general formalism allows the use of
any additional constraint for the inductive cross-field velocity to enforce a
unique solution in the induction equation. As a result, our methodology can
give rise to new velocity solutions besides the one presented here. To
constrain the induction equation, we use a special case of the minimum
structure approximation that was introduced in previous studies and is already
employed here to resolve the $180^o$-ambiguity in the input vector
magnetograms. We reconstruct the inductive velocity for three active regions,
including NOAA AR 8210 for which previous results exist. Our solution
believably reproduces the horizontal flow patterns in the studied active
regions but breaks down in cases of localized rapid magnetic flux emergence or
submergence. Alternative approximations and constraints are possible and can be
accommodated into our general formalism.


title: Evolving structures of star-forming clusters

abstract:
  Understanding the formation and evolution of young star clusters requires
quantitative statistical measures of their structure. We investigate the
structures of observed and modelled star-forming clusters. By considering the
different evolutionary classes in the observations and the temporal evolution
in models of gravoturbulent fragmentation, we study the temporal evolution of
the cluster structures. We apply different statistical methods, in particular
the normalised mean correlation length and the minimum spanning tree technique.
We refine the normalisation of the clustering parameters by defining the area
using the normalised convex hull of the objects and investigate the effect of
two-dimensional projection of three-dimensional clusters. We introduce a new
measure $\xi$ for the elongation of a cluster. It is defined as the ratio of
the cluster radius determined by an enclosing circle to the cluster radius
derived from the normalised convex hull. The mean separation of young stars
increases with the evolutionary class, reflecting the expansion of the cluster.
The clustering parameters of the model clusters correspond in many cases well
to those from observed ones, especially when the $\xi$ values are similar. No
correlation of the clustering parameters with the turbulent environment of the
molecular cloud is found, indicating that possible influences of the
environment on the clustering behaviour are quickly smoothed out by the stellar
velocity dispersion. The temporal evolution of the clustering parameters shows
that the star cluster builds up from several subclusters and evolves to a more
centrally concentrated cluster, while the cluster expands slower than new stars
are formed.


title:
Turbulence in the Solar Atmosphere: Manifestations and Diagnostics via
  Solar Image Processing

abstract:
  Intermittent magnetohydrodynamical turbulence is most likely at work in the
magnetized solar atmosphere. As a result, an array of scaling and multi-scaling
image-processing techniques can be used to measure the expected
self-organization of solar magnetic fields. While these techniques advance our
understanding of the physical system at work, it is unclear whether they can be
used to predict solar eruptions, thus obtaining a practical significance for
space weather. We address part of this problem by focusing on solar active
regions and by investigating the usefulness of scaling and multi-scaling
image-processing techniques in solar flare prediction. Since solar flares
exhibit spatial and temporal intermittency, we suggest that they are the
products of instabilities subject to a critical threshold in a turbulent
magnetic configuration. The identification of this threshold in scaling and
multi-scaling spectra would then contribute meaningfully to the prediction of
solar flares. We find that the fractal dimension of solar magnetic fields and
their multi-fractal spectrum of generalized correlation dimensions do not have
significant predictive ability. The respective multi-fractal structure
functions and their inertial-range scaling exponents, however, probably provide
some statistical distinguishing features between flaring and non-flaring active
regions. More importantly, the temporal evolution of the above scaling
exponents in flaring active regions probably shows a distinct behavior starting
a few hours prior to a flare and therefore this temporal behavior may be
practically useful in flare prediction. The results of this study need to be
validated by more comprehensive works over a large number of solar active
regions.


title:
Study of the relationship between the gamma ray bursts and their host
  galaxies

abstract:
  Gamma ray bursts (GRBs) belong to the most energetic events in the Universe.
Recently, the extragalactic nature of these sources has been confirmed with the
discovery of several host galaxies (HGs) and the measurement of their
redshifts. To explain the origin of GRBs various models have been proposed,
among which the coalescence of compact objects and the "collapsar" scenarios
are the most representative, being the collapsar model one of the most accepted
to explain the long duration GRBs. A natural consequence of this model is that
the GRBs would trace the star formation rate (SFR) of their HGs. In this
contributed paper we present preliminary results of the development of a
Montecarlo-based code for collapsar event formation which is coupled to
chemical-cosmological simulations aiming at studying the properties of HGs in a
hierarchical scenario.


title: Hot Gas in Galaxy Clusters: Theory and Simulations

abstract:
  We review the theory of the formation of galaxy clusters and discuss their
role as cosmological probes. We begin with the standard cosmological framework
where we discuss the origin of the CDM matter power spectrum and the growth of
density fluctuations in the linear regime. We then summarize the spherical
top-hat model for the nonlinear growth of fluctuations from which scaling
relations and halo statistics are derived. Numerical methods for simulating gas
in galaxy clusters are then overviewed with an emphasis on multiscale
hydrodynamic simulations of cluster ensembles. Results of hydrodynamic AMR
simulations are described which compare cluster internal and statistical
properties as a function of their assumed baryonic processes. Finally, we
compare various methods of measuring cluster masses using X-ray and the thermal
Sunyaev-Zeldovich effect (SZE). We find that SZE offers great promise for
precision measurements in raw samples of high-z clusters.


title:
Early Cosmic Chemical Evolution: Relating the Origin of a Diffuse
  Intergalactic Medium and the First Long-Lived Stars

abstract:
  Nucleosynthetic signatures in common between the gas responsible for the high
redshift Lyman alpha forest and a subsample of extremely metal poor stars are
found. A simple mass loss model of chemical evolution with physically motivated
parameters provides a consistent picture in which the gas is identified with
that lost by supernova-driven winds during the first generation of star
formation. Substantial mass loss occurs which can account for a diffuse IGM
with up to 80% of the total baryon content and a peak [C-O/H] abundance of
\~-2.9. This mass loss component differs from one produced later during galaxy
formation and evolution that contributes to a circum-galactic medium (CGM). The
CGM was shown earlier to have a mass of ~10% of all baryons and peak [Fe/H]~-1.


title:
The Sloan Lens ACS Survey. I. A Large Spectroscopically Selected Sample
  of Massive Early-Type Lens Galaxies

abstract:
  The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope
Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The
targeted lens candidates are selected spectroscopically from within the Sloan
Digital Sky Survey (SDSS) database of galaxy spectra for having multiple
nebular emission lines at a redshift significantly higher than that of the SDSS
target galaxy. In this paper, we present a catalog of 19 newly discovered
gravitational lenses, along with 9 other observed candidate systems that are
either possible lenses, non-lenses, or non-detections. The survey efficiency is
thus >=68%. We also present Gemini and Magellan IFU data for 9 of the SLACS
targets, which further support the lensing interpretation. A new method for the
effective subtraction of foreground galaxy images to reveal faint background
features is presented. We show that the SLACS lens galaxies have colors and
ellipticities typical of the spectroscopic parent sample from which they are
drawn (SDSS luminous red galaxies and quiescent main-sample galaxies), but are
somewhat brighter and more centrally concentrated. Several explanations for the
latter bias are suggested. The SLACS survey provides the first statistically
significant and homogeneously selected sample of bright early-type lens
galaxies, furnishing a powerful probe of the structure of early-type galaxies
within the half-light radius. The high confirmation rate of lenses in the SLACS
survey suggests consideration of spectroscopic lens discovery as an explicit
science goal of future spectroscopic galaxy surveys (abridged).


title: New Photometric Observations of sigma Ori E

abstract:
  We present new UBVRI observations of the magnetic Bp star sigma Ori E. The
basic features of the star's lightcurve have not changed since the previous
monitoring by Hesser et al. (1977), indicating that the star's magnetosphere
has remained stable over the past three decades. Interestingly, we find a
rotation period that is slightly longer than in the Hesser et al. (1977)
analysis, suggesting possible spindown of the star.


title: Kappa-Mechanism Excitation of Retrograde Mixed Modes in B-Type Stars

abstract:
  The stability of retrograde mixed modes in rotating B-type stars is
investigated. It is found that these modes are susceptible to kappa-mechanism
excitation, due to the iron opacity bump at log T ~ 5.3. The findings are
discussed in the context of the pulsation of SPB and Be stars.


title: sigma Ori E: The Archetypal Rigidly Rotating Magnetosphere

abstract:
  I review the basic concepts of the Rigidly Rotating Magnetosphere model for
the circumstellar plasma distribution around the helium-strong star sigma Ori
E. I demonstrate that the model can furnish a good fit to the photometric,
spectroscopic and magneticv ariability exhibited by this star, and argue that
the variability of other helium-strong stars may be amenable to a similar
interpretation.


title: An Explanation for the soft X-ray excess in AGN

abstract:
  We present a large sample of type 1 active galactic nuclei (AGN) spectra
taken with XMM-Newton, and fit them with both the conventional model (a power
law and black body) and the relativistically-blurred photoionized disc
reflection model of Ross and Fabian (2005). We find the disc reflection model
is a better fit. The disc reflection model successfully reproduces the
continuum shape, including the soft excess, of all the sources. The model also
reproduces many features that would conventionally be interpreted as absorption
edges. We are able to use the model to infer the properties of the sources;
specifically that the majority of black holes in the sample are strongly
rotating and that there is a deficit in sources with an inclination > 70
degrees. We conclude that the disc reflection model is an important tool in the
study of AGN X-ray spectra.


title:
Astronomical databases, Space photometry and time series analysis: Open
  questions

abstract:
  How to analyse Terabytes of photometric data, and extract knowledge on
variable stars? How to detect variable phenomena? How to combine different
photometric bands? Which algorithm to search for periods? How to characterize
and classify the detected variable objects? Many questions, but certainly no
definitive answers yet. We present several aspects which are at the interface
of photometric surveys and variable stars. Fully automated analyses of
photometric surveys are still not at an optimized level. We will take the
example of a future survey, the Gaia mission project of the European Space
Agency, to show different steps of a possible automated pipeline scheme.
Principal component analysis can be applied to the Gaia photometric bands. We
give some illustrative examples of classification methods such as Support
Vector Machine, Self-Organising Map, or Bayesian classifier.


title:
Deep Chandra and multicolor HST follow-up of the jets in two powerful
  radio quasars

abstract:
  We present deep (70-80 ks) Chandra and multicolor HST ACS images of two jets
hosted by the powerful quasars 1136-135 and 1150+497, together with new radio
observations. The sources have an FRII morphology and were selected from our
previous X-ray and optical jet survey for detailed follow up aimed at obtaining
better constraints on the jet multiwavelength morphology and X-ray and optical
spectra of individual knots, and to test emission models deriving physical
parameters more accurately. All the X-ray and optical knots detected in our
previous short exposures are confirmed, together with a few new faint features.
The overlayed maps and the emissivity profiles along the jet show good
correspondence between emission regions at the various wavelengths; a few show
offsets between the knots peaks of <1". In 1150+497 the X-ray, optical, and
radio profiles decrease in similar ways with distance from the core up to ~7",
after which the radio emission increases more than the X-ray one. No X-ray
spectral variations are observed in 1150+497. In 1136-135 an interesting
behavior is observed, whereby, downstream of the most prominent knot at ~ 6.5"
from the core, the X-ray emission fades while the radio emission brightens. The
X-ray spectrum also varies, with the X-ray photon index flattening from ~2 in
the inner part to ~1.7 to the end of the jet. We intepret the jet behavior in
1136-135 in a scenario where the relativistic flow suffers systematic
deceleration along the jet, and briefly discuss the major consequences of this
scenario (abridged).


title: The Gaia mission. Pulsating stars with Gaia

abstract:
  Gaia is a cornerstone mission of the European Space Agency (ESA) selected in
2000, with a target launch date of 2011. The Gaia mission will perform a survey
of about 1 billion sources brighter than V=20. Its goal is to provide
astrometry leading to parallaxes, proper-motions and positions. Astrometric
data are complemented by multicolour photometry and a spectroscopic instrument
(up to V=17 mag) to provide astrophysical parameters (as effective
temperatures, surface gravities, metallicities) and radial velocities. The
survey will have multi-epoch observations allowing a detection of the variable
sources; objects will be measured as a mean 80/100 times over the 5 year
mission length in the two instruments on board, the Astro-/Spectro-instruments
respectively.
  The data processing of the mission is a major challenge: as a first step
working groups on different themes were created and have been active. One
working group has been dedicated to variable stars. A consortium for the data
processing is currently being created, the Data Processing and Analysis
Consortium.
  Though several aspects of the Gaia mission are under possible changes, we
review some activities related to the mission in the perspective of pulsating
stars.


title: Spectroscopy of Four Cataclysmic Variables with Periods above 7 Hours

abstract:
  We present spectroscopy of four cataclysmic variables. Using radial velocity
measurements, we find orbital periods for the first time. The stars and their
periods are GY Hya, 0.347230(9) d; SDSS J204448-045929, 1.68(1) d; V392 Hya,
0.324952(5) d; and RX J1951.7+3716, 0.492(1) d. We also detect the spectra of
the secondary stars, estimate their spectral types, and derive distances based
on surface brightness and Roche lobe constraints.


title: Discovery of a Very Young Field L Dwarf, 2MASS J01415823-4633574

abstract:
  While following up L dwarf candidates selected photometrically from the Two
Micron All Sky Survey, we uncovered an unusual object designated 2MASS
J01415823-4633574. Its optical spectrum exhibits very strong bands of vanadium
oxide but abnormally weak absorptions by titanium oxide, potassium, and sodium.
Morphologically such spectroscopic characteristics fall intermediate between
old, field early-L dwarfs (log(g)~5) and very late M giants (log(g)~0), leading
us to favor low gravity as the explanation for the unique spectral signatures
of this L dwarf. Such a low gravity can be explained only if this L dwarf is
much lower in mass than a typical old field L dwarf of similar temperature and
is still contracting to its final radius. These conditions imply a very young
age. Further evidence of youth is found in the near-infrared spectrum,
including a triangular-shaped H-band continuum reminiscent of young brown dwarf
candidates discovered in the Orion Nebula Cluster. Using the above information
along with comparisons to brown dwarf atmospheric and interior models, our
current best estimate is that this L dwarf has an age of 1-50 Myr and a mass of
6-25 M_Jupiter. The location of 2MASS 0141-4633 on the sky coupled with a
distance estimate of ~35 pc and the above age estimate suggests that this
object may be a brown dwarf member of either the 30-Myr-old Tucana/Horologium
Association or the ~12-Myr-old beta Pic Moving Group.


title:
Orbital configurations and dynamical stability of multi-planet systems
  around Sun-like stars HD 202206, 14 Her, HD 37124 and HD 108874

abstract:
  We perform a dynamical analysis of the recently published radial velocity
(RV) measurements of a few solar type stars which host multiple Jupiter-like
planets. In particular, we re-analyze the data for HD 202206, 14 Her, HD 37124
and HD 108874. We derive dynamically stable configurations which reproduce the
observed RV signals using our method called GAMP (an acronym of the Genetic
Algorithm with MEGNO Penalty). The GAMP relies on the N-body dynamics and makes
use of genetic algorithms merged with a stability criterion. For this purpose,
we use the maximal Lyapunov exponent computed with the dynamical fast indicator
MEGNO. Through a dynamical analysis of the phase-space in a neighborhood of the
obtained best-fit solutions, we derive meaningful limits on the parameters of
the planets. We demonstrate that GAMP is especially well suited for the
analysis of the RV data which only partially cover the longest orbital period
and/or correspond to multi-planet configurations involved in low-order mean
motion resonances (MMRs). In particular, our analysis reveals a presence of a
second Jupiter-like planet in the 14 Her system (14 Her c) involved in a 3:1 or
6:1 MMR with the known companion b. We also show that the dynamics of the HD
202206 system may be qualitatively different when coplanar and
mutually-inclined orbits of the companions are considered. We demonstrate that
the two outer planets in the HD 37124 system may reside in a close neighborhood
of the 5:2 MMR. Finally, we found a clear indication that the HD 108874 system
may be very close to, or locked in an exact 4:1 MMR.


title:
AGN Feedback and Evolution of Radio Sources: Discovery of an X-ray
  Cluster Associated with z=1 Quasar

abstract:
  We report the first significant detection of an X-ray cluster associated with
a powerful (L(bol) ~1e47 erg/sec) radio-loud quasar at high redshift (z=1.06).
Diffuse X-ray emission is detected out to ~120 kpc from the CSS quasar 3C 186.
A strong Fe-line emission at the z(rest)=1.06 confirms its thermal nature. We
find that the CSS radio source is highly overpressured with respect to the
thermal cluster medium by ~2-3 orders of magnitude. This provides direct
observational evidence that the radio source is not thermally confined as
posited in the ``frustrated'' scenario for CSS sources. Instead, the radio
source may be young and at an early stage of its evolution. This source
provides the first detection of the AGN in outburst in the center of a cooling
flow cluster. Powerful radio sources are thought to be triggered by the cooling
flows. The evidence for the AGN activity and intermittent outbursts comes from
the X-ray morphology of low redshift clusters, which usually do not harbour
quasars. 3C186 is a young active radio source which can supply the energy into
the cluster and potentially prevent its cooling. We discuss energetics related
to the quasar activity and the cluster cooling flow, and possible feedback
between the evolving radio source and the cluster.


title: Internal Kinematics of the Fornax Dwarf Spheroidal Galaxy

abstract:
  We present new radial velocity results for 176 stars in the Fornax dwarf
spheroidal galaxy, of which at least 156 are probable Fornax members. We
combine with previously published data to obtain a radial velocity sample with
206 stars, of which at least 176 are probable Fornax members. We detect the
hint of rotation about an axis near Fornax's morphological minor axis, though
the significance of the rotation signal in the galactic rest frame is sensitive
to the adopted value of Fornax's proper motion. Regardless, the observed
stellar kinematics are dominated by random motions, and we do not find
kinematic evidence of tidal disruption. The projected velocity dispersion
profile of the binned dataset remains flat over the sampled region, which
reaches a maximum angular radius of 65 arcmin. Single-component King models in
which mass follows light fail to reproduce the observed flatness of the
velocity dispersion profile. Two-component (luminous plus dark matter) models
can reproduce the data, provided the dark component extends sufficiently beyond
the luminous component, and the central dark matter density is of the same
order as the central luminous density. These requirements suggest a more
massive, darker Fornax than standard core-fitting analyses have previously
concluded, with M/L_V over the sampled region reaching 10 to 40 times the M/L_V
of the luminous component. We also apply a non-parametric mass estimation
technique, introduced in a companion paper. Though it is designed to operate on
datasets containing velocities for $>$1000 stars, the estimation yields
preliminary results suggesting M/L_V ~ 15 inside r < 1.5 kpc.


title:
XMM observes ClJ0152.7-1357: A massive galaxy cluster forming at merger
  crossroads at z=0.83

abstract:
  We present an analysis of a 50ks XMM observation of the merging galaxy
cluster ClJ0152.7-1357 at z=0.83. In addition to the two main subclusters and
an infalling group detected in an earlier Chandra observation of the system,
XMM detects another group of galaxies possibly associated with the cluster.
This group may be connected to the northern subcluster by a filament of cool
(1.4^{+0.3}_{-0.1}keV) X-ray emitting gas, and lies outside the estimated
virial radius of the northern subcluster. The X-ray morphology agrees well with
the projected galaxy distribution in new K-band imaging data presented herein.
We use detailed spectral and imaging analysis of the X-ray data to probe the
dynamics of the system and find evidence that another subcluster or group has
recently passed through the northern subcluster. ClJ0152.7-1357 is an extremely
dynamically active system with mergers at different stages occurring along two
perpendicular merger axes.


title:
Spitzer Mid-infrared Spectroscopy of Ices Toward Extincted Background
  Stars

abstract:
  A powerful way to observe directly the solid state inventory of dense
molecular clouds is by infrared spectroscopy of background stars. We present
Spitzer/IRS 5-20 micron spectra of ices toward stars behind the Serpens and
Taurus molecular clouds, probing visual extinctions of 10-34 mag. These data
provide the first complete inventory of solid-state material in dense clouds
before star formation begins. The spectra show prominent 6.0 and 6.85 micron
bands. In contrast to some young stellar objects (YSOs), most (~75%) of the 6.0
micron band is explained by the bending mode of pure water ice. In realistic
mixtures this number increases to 85%, because the peak strength of the water
bending mode is very sensitive to the molecular environment. The strength of
the 6.85 micron band is comparable to what is observed toward YSOs. Thus, the
production of the carrier of this band does not depend on the energetic input
of a nearby source. The spectra show large abundances of carbon monoxide and
carbon dioxide (20-40% with respect to water ice). Compared to YSOs, the band
profile of the 15 micron carbon dioxide bending mode lacks the signatures of
crystallization, confirming the cold, pristine nature of these lines of sight.
After the dominant species are removed, there are residuals that suggest the
presence of minor species such as formic acid and possibly ammonia. Clearly,
models of star formation should begin with dust models already coated with a
fairly complex mixture of ices.


title: Photometry and Spectroscopy of KS Ursae Majoris during Superoutburst

abstract:
  We report photometric and spectroscopic observations of the SU UMa-type dwarf
novae, KS Ursae Majoris, during its 2003 February superoutburst. Modulations
with a period of $0.07017\pm0.00021$ day, which is 3.3% larger than the orbital
period, have been found during the superoutburst and may be positive
superhumps. A maximum trough-to-peak amplitude of around 0.3 magnitude is
determined for this superhump.
  The spectra show broad, absorption-line profiles. The lines display blue and
red troughs which alternate in depth. The radial velocity curve of the
absorption wings of H$\beta$ has an amplitude of $40\pm11$ km s$^{-1}$ and a
phase offset of $0.12\pm0.03$. The $\gamma$ velocity of the binary is $3\pm9$
km s$^{-1}$ and varies on an order of 50 km s$^{-1}$ from day to day. From
another clear evidence for a precessing eccentric disk, we obtain a solution to
an eccentric outer disk consistent with theoretical works, which demonstrates
the validity of the relation between superhumps and tidal effects. The inner
part of the disk is also eccentric as evidenced by asymmetric and symmetric
wings in the lines. Therefore, the whole disk is eccentric and the variation of
$\gamma$ velocity and the evolutionary asymmetric line profiles could be
criterions for an precessing eccentric accretion disk.


title:
Are protons still dominant at the knee of the cosmic-ray energy
  spectrum?

abstract:
  A hybrid experiment consisting of emulsion chambers, burst detectors and the
Tibet II air-shower array was carried out at Yangbajing (4,300 m a.s.l., 606
g/cm$^2$) in Tibet to obtain the energy spectra of primary protons and heliums.
  From three-year operation, these energy spectra are deduced between $10^{15}$
and $10^{16}$ eV by triggering the air showers associated with a high energy
core and using a neural network method in the primary mass separation. The
proton spectrum can be expressed by a single power-law function with a
differential index of $-3.01 \pm 0.11$ and $-3.05 \pm 0.12$ based on the
QGSJET+HD and SIBYLL+HD models, respectively, which are steeper than that
extrapolated from the direct observations of $-2.74 \pm 0.01$ in the energy
range below $10^{14}$ eV. The absolute fluxes of protons and heliums are
derived within 30% systematic errors depending on the hadronic interaction
models used in Monte Carlo simulation. The result of our experiment suggests
that the main component responsible for the change of the power index of the
all-particle spectrum around $3 \times 10^{15}$ eV, so-called ``knee'', is
composed of nuclei heavier than helium. This is the first measurement of the
differential energy spectra of primary protons and heliums by selecting them
event by event at the knee energy region.


title:
Dedicated Supernova Detection by a Network of Neutral Current Spherical
  TPC's

abstract:
  Supernova neutrinos can easily be detected by a spherical gaseous TPC
detector measuring very low energy nuclear recoils. The expected rates are
quite large for a neutron rich target since the neutrino nucleus neutral
current interaction yields a coherent contribution of all neutrons. As a matter
of fact for a typical supernova at 10 kpc, about 1000 events are expected using
a spherical detector of radius 4 m with Xe gas at a pressure of 10 Atm. A world
wide network of several such simple, stable and low cost supernova detectors
with a running time of a few centuries is quite feasible.


title:
Strong Emission-Line Galaxies at Low Redshift in the Field around the
  Quasar SDSSp J104433.04-012502.2

abstract:
  We discuss observational properties of strong emission-line galaxies at low
redshift found by our deep imaging survey for high-redshift Ly alpha emitters.
In our surveys, we used the narrowband filter, NB816 (lambda_center=8150A with
FWHM = 120A), and the intermediate-band filter, IA827 (lambda_center = 8270A
with FWHM = 340A). In this survey, 62 NB816-excess (> 0.9 mag) and 21
IA827-excess (> 0.8 mag) objects were found. Among them, we found 20
NB816-excess and 4 IA827-excess Ly alpha emitter candidates. Therefore, it
turns out that 42 NB816-excess and 17 IA827-excess objects are strong
emission-line objects at lower redshift. Since 4 objects in the two low-z
samples are common, the total number of strong low-z emitters is 55. Applying
our photometric redshift technique, we identify 7 H alpha emitters at z~0.24,
20 H beta-[OIII] ones at z~0.65, and 11 [OII] ones at z~1.19. However, we
cannot determine reliable photometric redshifts of the remaining 17 emitters.
The distributions of their rest frame equivalent widths are consistently
understood with recent studies of galaxy evolution from z~1 to z~0.


title:
Probing the internal magnetic field of slowly pulsating B-stars through
  g modes

abstract:
  We suggest that high-order g modes can be used as a probe of the internal
magnetic field of SPB (slowly pulsating B) stars. The idea is based on earlier
work by the authors which analytically investigated the effect of a vertical
magnetic field on p and g modes in a plane-parallel isothermal stratified
atmosphere. It was found that even a weak field can significantly shift the
g-mode frequencies -- the effect increases with mode order. In the present
study we adopt the classical perturbative approach to estimate the internal
field of a 4 solar mass SPB star by looking at its effect on a low-degree
($l=1$) and high-order ($n=20$) g mode with a period of about 1.5 d. We find
that a polar field strength of about 110 kG on the edge of the convective core
is required to produce a frequency shift of 1%. Frequency splittings of that
order have been observed in several SPB variables, in some cases clearly too
small to be ascribed to rotation. We suggest that they may be due to a poloidal
field with a strength of order 100 kG, buried in the deep interior of the star.


title:
Confronting Braneworld Cosmology with Supernova data and Baryon
  Oscillations

abstract:
  Braneworld cosmology has several attractive and distinctive features. For
instance the effective equation of state in braneworld models can be both
quintessence-like (w_0 \geq -1) as well as phantom-like (w_0 \leq -1). Models
with w_0 \geq -1 (w_0 \leq -1) are referred to as Brane 2 (Brane 1) and
correspond to complementary embeddings of the brane in the bulk. (The equation
of state in Brane 1 can successfully cross the `phantom divide' at w = -1.) In
this paper we compare the predictions of braneworld models to two recently
released supernova data sets: the `Gold' data (Riess et al, 2004) and the data
from the Supernova Legacy Survey (SNLS) (Astier et al, 2005). We also
incorporate the recent discovery of the baryon acoustic peak in the Sloan
Digital Sky Survey (Eisenstein et al, 2005) into our analysis. Our main results
are that braneworld models satisfy both sets of SNe data. Brane 1 (with w_0
\leq -1) shows very good agreement with data for values of the matter density
bounded {\em from below}: \Omega_m \geq 0.25 (Gold) and $\Omega_m \geq 0.2
(SNLS). On the other hand Brane 2 (with w_0 \geq -1) shows excellent agreement
with data for values of the matter density which are bounded {\em from above}:
\Omega_m \leq 0.45 (Gold) and \Omega_m \leq 0.35 (SNLS). The DGP model is
excluded at 3\sigma by SNLS and at 1\sigma by the Gold dataset. Braneworld
models with future `quiescent' singularities (at which the Hubble parameter and
the matter density remain finite but higher derivatives of the expansion factor
diverge) are excluded by both datasets.


title: Constraining dark energy interacting models with WMAP

abstract:
  We determine the range of parameter space of an interacting quintessence (IQ)
model that best fits the luminosity distance of type Ia supernovae data and the
recent WMAP measurements of Cosmic Microwave Background temperature
anisotropies. Models in which quintessence decays into dark matter provide a
clean explanation for the coincidence problem. We focus on cosmological models
of zero spatial curvature. We show that if the dark energy (DE) decays into
cold dark matter (CDM) at a rate that brings the ratio of matter to dark energy
constant at late times, the supernovae data are not sufficient to constrain the
interaction parameter. On the contrary, WMAP data constrain it to be smaller
than $c^2 < 10^{-2}$ at the $3\sigma$ level. Accurate measurements of the
Hubble constant and the dark energy density, independent of the CMB data, would
support/disprove this set of models.


title: The mid- and far-infrared colours of AGB and post-AGB stars

abstract:
  With the advent of space missions, like SPITZER and ASTRO-F, with sensitive
detectors in the near- and mid-infra red covering a reasonable field-of-view
and having a good spatial resolution, it will be possible to detect individual
AGB stars in Local Group galaxies. The filters used by these missions are
non-standard and different from mission to mission.
  In this paper, the colours of mass-losing AGB and post-AGB stars are
calculated in the broad-band filters of the SPITZER and ASTRO-F missions, as
well as Bessell V,I and 2MASS J,H,K to connect these results to existing
ground-based data.
  The models are calculated for carbon- and oxygen-rich chemistry and cover
different effective temperatures and dust compositions.


title:
From the Spectrum to Inflation: A Second Order Inverse Formula for the
  General Slow-Roll Spectrum

abstract:
  We invert the second order, single field, general slow-roll formula for the
power spectrum, to obtain a second order formula for inflationary parameters in
terms of the primordial power spectrum.


title:
Radio and X-Ray Emission Associated with the Supernova Remnant
  G352.7-0.1

abstract:
  We report on new VLA radio and XMM-Newton X-ray observations of the SNR
G352.7-0.1. These high sensitivity, high resolution data reveal that G352.7-0.1
belongs to the thermal composite morphological class. Small scale structures in
radio and X-ray emission are not always correlated and are different for the
different X-rays bands examined. The distance to G352.7-0.1 can be constrained
between 6.6 and 8.4 kpc. The study of the HI suggests that G352.7-0.1 is
located within a cavity probably created by the stellar wind of the precursor
star.


title: An explicit scheme for multifluid magnetohydrodynamics

abstract:
  When modeling astrophysical fluid flows, it is often appropriate to discard
the canonical magnetohydrodynamic approximation thereby freeing the magnetic
field to diffuse with respect to the bulk velocity field. As a consequence,
however, the induction equation can become problematic to solve via standard
explicit techniques. In particular, the Hall diffusion term admits fast-moving
whistler waves which can impose a vanishing timestep limit.
  Within an explicit differencing framework, a multifluid scheme for weakly
ionised plasmas is presented which relies upon a new approach to integrating
the induction equation efficiently. The first component of this approach is a
relatively unknown method of accelerating the integration of parabolic systems
by enforcing stability over large compound timesteps rather than over each of
the constituent substeps. This method, Super Time Stepping, proves to be very
effective in applying a part of the Hall term up to a known critical value. The
excess of the Hall term above this critical value is then included via a new
scheme for pure Hall diffusion.


title: Search for dense molecular gas in QSO hosts

abstract:
  We present the results of a recently conducted mm-experiment at the IRAM 30m
telescope. We searched in two QSO hosts for the HCN(J=1-0) line emission
tracing the dense regions of gas. Our goal is to probe the HCN-CO line ratio in
QSO hosts for the first time and to compare the results with recent findings of
quiescent galaxies. These findings indicate a strong correlation between the
star formation efficiency and the HCN-CO line ratio over several orders of
magnitudes in infrared luminosities.


title:
Three Dimensional Simulation of Gamma Ray Emission from Asymmetric
  Supernovae and Hypernovae

abstract:
  Hard X- and $\gamma$-ray spectra and light curves resulting from radioactive
decays are computed for aspherical (jet-like) and energetic supernova models
(representing a prototypical hypernova SN 1998bw), using a 3D energy- and
time-dependent Monte Carlo scheme. The emission is characterized by (1) early
emergence of high energy emission, (2) large line-to-continuum ratio, and (3)
large cut-off energy by photoelectric absorptions in hard X-ray energies. These
three properties are not sensitively dependent on the observer's direction. On
the other hand, fluxes and line profiles depend sensitively on the observer's
direction, showing larger luminosity and larger degree of blueshift for an
observer closer to the polar ($z$) direction. Strategies to derive the degree
of asphericity and the observer's direction from (future) observations are
suggested on the basis of these features, and an estimate on detectability of
the high energy emission by the {\it INTEGRAL} and future observatories is
presented. Also presented is examination on applicability of a gray effective
$\gamma$-ray opacity for computing the energy deposition rate in the aspherical
SN ejecta. The 3D detailed computations show that the effective $\gamma$-ray
opacity $\kappa_{\gamma} \sim 0.025 - 0.027$ cm$^{2}$ g$^{-1}$ reproduces the
detailed energy-dependent transport for both spherical and aspherical
(jet-like) geometry.


title: X-ray source populations in galaxies

abstract:
  Today's sensitive, high-resolution X-ray observations allow the study of
populations of X-ray sources, in the luminosity range of Galactic X-ray
binaries, in galaxies as distant as 20-30 Mpc. The traditional astronomical
tools of photometric diagrams and luminosity functions are now applied to these
populations, providing a direct probe of the evolved binary component of
different stellar populations. The study of the X-ray populations of E and S0
galaxies has revamped the debate on the formation and evolution of low-mass
X-ray binaries (LMXBs) and on the role of globular clusters in these processes.
While overall stellar mass drives the amount of X-ray binaries in old stellar
populations, the amount of sources in star forming galaxies is related to the
star formation rate. Short-lived, luminous, high-mass binaries (HMXBs) dominate
these young populations. The most luminous sources in these systems are the
debated ULXs, which have been suggested to be ~100-1000 Msol black holes, but
could alternatively include a number of binaries with stellar mass black holes.
Very soft sources have also been discovered in many galaxies and their nature
is currently being debated. Observations of the deep X-ray sky, and comparison
with deep optical surveys, are providing the first evidence of the X-ray
evolution of galaxies.


title:
Study of the Origin of the Luminosity-Metallicity and the Stellar
  Mass-Metallicity Relations in Hierarchical Universes

abstract:
  In this work, we study the Luminosity-Metallicity relation (LMR) and the
Stellar Mass -Metallicity relation (MMR) of galactic systems in a hierarhical
clustering scenario. We performed numerical hydrodynamical simulations with the
chemical GADGET-2 of Scannapieco et al.(2005) in a LCDM universe.
  We found that our simulated galactic systems reproduce the observed local LMR
and its evolution in zero point and slope. The simulated MMR is also in
agreement with recent observational results. From the analysis of the evolution
of the MMR, we found a characteristic mass at ~10^(10.2) M_sun / h which
separates two galactic populations with different astrophysical properties.
More massive systems tend to have their stars formed at z > 2 and show less
evolution than smaller systems. Hence, this characteristic mass is determined
by the formation of the structure in a hierarchical scenario. Our results also
suggest the need for important supernova feedback.


title: Strongly Interacting Astrophysical Neutrinos

abstract:
  The origin and chemical composition of ultra high energy cosmic rays is still
an open question in astroparticle physics. The observed large-scale isotropy
and also direct composition measurements can be interpreted as an extragalactic
proton dominance above the ankle at about 10^10 GeV. Photopion production of
extragalactic protons in the cosmic microwave background predicts a cutoff at
about 5x10^10 GeV in conflict with excesses reported by some experiments. In
this report we will outline a recent statistical analysis (astro-ph/0506698) of
cosmic ray data using strongly interacting neutrinos as primaries for these
excesses.


title: Circular Polarimetry and the Line of Sight to the BN Object

abstract:
  The 3.1 micron absorption feature of water-ice has been observed
spectroscopically in many molecular clouds and, when it has been observed
spectropolarimetrically, usually a corre- sponding polarization feature is
seen. Typically on these occasions, and particularly for the BN object, a
distinct position angle shift between the feature and continuum is seen, which
indicates both a fractionation of the icy material and a changing alignment
direction along the line of sight.
  Here the dependence of circular polarimetry on fractionation along the line
of sight is investigated and it is shown that the form of its spectrum,
together with the sign of the position angle shift, indicates where along the
line of sight the icy material lies. More specifically a coincidence between
the sign of the position angle displacement in the ice feature, measured north
through east, and that of the circular polarization ice feature means that the
icy grains are overlaid by bare grains. Some preliminary circular polarimetry
of BN has this characteristic and a similar situation is found in the only two
other cases for which relevant observations so far exist.


title:
The role of differential rotation in the evolution of the r-mode
  instability

abstract:
  We discuss the role of differential rotation in the evolution of the l=2
r-mode instability of a newly born, hot, rapidly-rotating neutron star. It is
shown that the amplitude of the r-mode saturates in a natural way at a value
that depends on the amount of differential rotation at the time the instability
becomes active. It is also shown that, independently of the saturation
amplitude of the mode, the star spins down to a rotation rate that is
comparable to the inferred initial rotation rates of the fastest pulsars
associated with supernova remnants.


title: The faintest accretors

abstract:
  Recent X-ray observations have detected a class of very faint X-ray
transients in the Galaxy which probably reveal a previously unrecognised type
of accretion on to neutron stars or black holes. We show that these systems
cannot have descended from binaries with stellar-mass components of normal
composition. Accretion of hydrogen-depleted matter on to stellar-mass black
holes can account for individual systems, but requires that these transients
should be observed to repeat within a few years, and does not explain why the
class is distinctly faint.
  Two other explanations appear to be quite natural. One invokes accretion by
neutron stars or stellar-mass black holes from companions which were already
brown dwarfs or planets when the systems formed, i.e. which did not descend
from low-mass stars. The other possibility is that these systems are the
endpoints of primordial (zero-metallicity) binaries in which the primary was
extremely massive, and collapsed to a black hole of mass > 1000 solar masses.
The (primordial) companion must by now have reached an extremely low mass (<
0.01 solar mass) and be transferring mass at a very low rate to the black hole.
This picture avoids the main difficulty encountered by models invoking
intermediate-mass black hole formation at non-primordial metallicities, and is
a natural consequence of some current ideas about Population III star
formation.


title: Multithermal Analysis of a CDS Coronal Loop

abstract:
  The observations from 1998 April 20 taken with the Coronal Diagnostics
Spectrometer CDS on SOHO of a coronal loop on the limb have shown that the
plasma was multi-thermal along each line of sight investigated, both before and
after background subtraction. The latter result relied on Emission Measure Loci
plots, but in this Letter, we used a forward folding technique to produce
Differential Emission Measure curves. We also calculate DEM-weighted
temperatures for the chosen pixels and find a gradient in temperature along the
loop as a function of height that is not compatible with the flat profiles
reported by numerous authors for loops observed with EIT on SOHO and TRACE. We
also find discrepancies in excess of the mathematical expectation between some
of the observed and predicted CDS line intensities. We demonstrate that these
differences result from well-known limitations in our knowledge of the atomic
data and are to be expected. We further show that the precision of the DEM is
limited by the intrinsic width of the ion emissivity functions that are used to
calculate the DEM. Hence we conclude that peaks and valleys in the DEM, while
in principle not impossible, cannot be confirmed from the data.


title: Future magnetic fields studies using the Planck Surveyor experiment

abstract:
  The Planck mission will permit measurements of the polarization of the cosmic
microwave background and of polarized foregrounds such as our own Galaxy with
an unprecedented combination of accuracy and completeness. This will provide
information on cosmological and galactic magnetic fields. The latter can be
studied in detail via nearly Faraday-rotation free synchrotron and polarized
dust emission. Methods are discussed to extract physically relevant information
on the magnetic turbulence from Planck data and other measurements.


title: The maximum contribution to reionization from metal-free stars

abstract:
  We estimate the maximum contribution to reionization from the first
generation of massive stars, with zero metallicity, under the assumption that
one of these stars forms with a fixed mass in every collapsed halo in which
metal-free gas is able to cool. We assume that any halo that has already had
stars previously formed in one of their halo progenitors will form only stars
with metals, which are assigned an emissivity of ionizing radiation equal to
that determined at z=4 from the measured intensity of the ionizing background.
We examine the impact of molecular hydrogen photodissociation (which tends to
reduce cooling when a photodissociating background is produced by the first
stars) and X-Ray photoheating (which heats the atomic medium, raising the
entropy of the gas before it collapses into halos). We find that in the
CDM$\Lambda$ model supported by present observations, and even assuming no
negative feedbacks for the formation of metal-free stars, a reionized mass
fraction of 50% is not reached until redshift $z\sim 12$. The combination of
ordinary metal-enriched stars and early metal-free stars can yield a CMB
optical depth to electron scattering of at most 0.13. The contribution of
metal-free stars to the present Cosmic Infrarred Background is negligibly
small.


title: Laue Lens Development for Hard X-rays (>60 keV)

abstract:
  Results of reflectivity measurements of mosaic crystal samples of Cu (111)
are reported. These tests were performed in the context of a feasibility study
of a hard X-ray focusing telescope for space astronomy with energy passband
from 60 to 600 keV. The technique envisaged is that of using mosaic crystals in
transmission configuration that diffract X-rays for Bragg diffraction (Laue
lens). The Laue lens assumed has a spherical shape with focal length $f$. It is
made of flat mosaic crystal tiles suitably positioned in the lens. The samples
were grown and worked for this project at the Institute Laue-Langevin (ILL) in
Grenoble (France), while the reflectivity tests were performed at the X-ray
facility of the Physics Department of the University of Ferrara.


title: Probable nonradial g-mode pulsation in early A-type stars

abstract:
  A survey for line profile variability in early A-type stars has been
performed in order to detect nonradial pulsation signatures. The star HR 6139,
with spectral type A2V and estimated T_eff=8800 K, shows evident line profile
variations that can be explained by oscillations in prograde g-modes. This
feature and the known photometric variability are similar to those observed in
the Slowly Pulsating B-type stars. However HR 6139 is much cooler than the cool
border of the instability strip of such variables, and it is hotter than the
blue edge of the delta Scuti instability strip. There are indications of a tiny
variability also in other four objects, whose nature is not yet clear.


title: Wide-field kinematics of globular clusters in the Leo I group

abstract:
  We present wide-field spectroscopy of globular clusters around the Leo I
group galaxies NGC 3379 and NGC 3384 using the FLAMES multi-fibre instrument at
the VLT. We obtain accurate radial velocities for 42 globular clusters (GCs) in
total, 30 for GCs around the elliptical NGC 3379, eight around the lenticular
NGC 3384, and four which may be associated with either galaxy. These data are
notable for their large radial range extending from 0'7 to 14'5 (2 to 42 kpc)
from the centre of NGC 3379, and small velocity uncertainties of about 10 km/s.
We combine our sample of 30 radial velocities for globular clusters around NGC
3379 with 8 additional GC velocities from the literature, and find a projected
velocity dispersion of 175(+24/-22) km/s at R < 5' and 147(+44/-39) at R > 5'.
These velocity dispersions are consistent with a dark matter halo around NGC
3379 with a concentration in the range expected from a LCDM cosmological model
and a total mass of ~ 6 x 10^11 Msun. Such a model is also consistent with the
stellar velocity dispersion at small radii and the rotation of the HI ring at
large radii, and has a M/L_B that increases by a factor of five from several
kpc to 100 kpc. Our velocity dispersion for the globular cluster system of NGC
3379 is somewhat higher than that found for the planetary nebulae (PNe) in the
inner region covered by the PN data, and we discuss possible reasons for this
difference. For NGC 3384, we find the GC system has a rotation signature
broadly similar to that seen in other kinematic probes of this SB0 galaxy. This
suggests that significant rotation may not be unusual in the GC systems of disc
galaxies.


title:
Oxygen and Iron Abundances in Nearby Galaxies Using Ultraluminous X-ray
  Sources

abstract:
  We determined oxygen and iron abundances of the interstellar medium (ISM)
using K-shell (O) and L-shell (Fe) X-ray photo-ionization edges towards Ultra
luminous X-ray sources (ULXs). We determine the hydrogen column densities (n_H)
towards the ULXs from XMM-Newton archival spectra of 14 ULX sources. We compare
our X-ray values with those obtained from radio HI observations for 8 of the
sources. The X-ray model n_H values are in good agreement with the HI n_H
values, implying that the hydrogen absorption towards the ULX is not local to
the source, with the exception of M81 X-1. Oxygen abundances and iron
abundances are roughly solar for the host galaxies.


title:
Destruction of small-scale dark matter clumps in the hierarchical
  structures and galaxies

abstract:
  A mass function of small-scale dark matter clumps is calculated in the
standard cosmological scenario with an inflationary-produced primordial
fluctuation spectrum and with a hierarchical clustering. We take into account
the tidal destruction of clumps at early stages of structure formation starting
from a time of clump detachment from the Universe expansion. Only a small
fraction of these clumps, ~0.1-0.5%, in each logarithmic mass interval
$\Delta\log M\sim1$ survives the stage of hierarchical clustering. The
surviving clumps can be disrupted further in the galaxies by tidal interactions
with stars. We performed the detailed calculations of the tidal destruction of
clumps by stars in the Galactic bulge and halo and by the Galactic disk itself.
It is shown that the Galactic disc provides the dominant contribution to the
tidal destruction of small-scale clumps outside the bulge. The results obtained
are crucial for calculations of the dark matter annihilation signal in the
Galaxy.


title: An End-to-End Test of Neutron Stars as Particle Accelerators

abstract:
  Combining resolved spectroscopy with deep imaging, XMM-Newton is providing
new insights on the particle acceleration processes long known to be at work in
the magnetospheres of isolated neutron stars. According to a standard
theoretical interpretation, in neutron stars' magnetospheres particles are
accelerated along the B field lines and, depending on their charge, they can
either move outward, to propagate in space, or be funnelled back, towards the
star surface. While particles impinging on the neutron star surface should heat
it at well defined spots, outgoing ones could radiate extended features in the
neutron star surroundings. By detecting hot spots, seen to come in and out of
sight as the star rotates, as well as extended features trailing neutron stars
as they move in the interstellar medium, XMM-Newton provides the first
end-to-end test to the particle acceleration process.


title: The radio loud narrow-line quasar SDSSJ172206.03+565451.6

abstract:
  We report identification of the radio loud narrow-line quasar SDSS
J172206.03+565451.6 which we found in the course of a search for radio loud
narrow-line Active Galactic Nuclei (AGN). SDSSJ172206.03+565451.6 is only the
~4th securely identified radio loud narrow-line quasar and the second-most
radio loudest with a radio index R_1.4 ~ 100-700. Its black hole mass, M_BH =
(2-3) 10^7 M_sun, is unusually small given its radio loudness, and the
combination of mass and radio index puts SDSSJ172206.03+565451.6 in a scarcely
populated region of M_BH-R diagrams. SDSSJ172206.03+565451.6 is a classical
Narrow-Line Seyfert1-type object with FWHM_Hbeta = 1490 km/s, an intensity
ratio of [OIII]/Hbeta = 0.7 and FeII emission complexes with FeII4570/Hbeta =
0.7. The ionization parameter of its narrow-line region, estimated from the
line ratio [OII]/[OIII], is similar to Seyferts and its high ratio of
[NeV]/[NeIII] indicates a strong EUV to soft-X-ray excess. We advertise the
combined usage of [OII]/[OIII] and [NeV]/[NeIII] diagrams as a useful
diagnostic tool to estimate ionization parameters and to constrain the EUV
continuum shape relatively independent from other parameters.


title:
A Spectroscopic Analysis of Blue Stragglers, Horizontal Branch and
  Turn-Off Stars in Four Globular Clusters

abstract:
  We present a spectroscopic analysis of HST/STIS and FOS low- and
intermediate-resolution spectroscopy of 55 stars (turn-off stars, horizontal
branch stars and blue stragglers) in four globular clusters (47 Tucanae, M3,
NGC6752, and NGC6397). Stars were analyzed with non-Local Thermodynamic
Equilibrium model atmospheres, and values for their effective temperatures and
gravities and some rotation rates were obtained. Using photometric fluxes, we
also obtained radii, luminosities and spectroscopic masses.


title:
Spectroscopy of GRB 050505 at z=4.275: A logN(HI)=22.1 DLA Host Galaxy
  and the Nature of the Progenitor

abstract:
  We present the discovery of the optical afterglow of GRB 050505 and an
optical absorption spectrum obtained with the Keck I 10-m telescope. The
spectrum exhibits three redshifted absorption systems with the highest, at
z=4.2748, arising in the GRB host galaxy. The host absorption system is marked
by a damped Ly-alpha (DLA) feature with a neutral hydrogen column density of
logN(HI)=22.05+/-0.10, higher than that of any QSO-DLA detected to date, but
similar to several other recent measurements from GRB spectra. In addition, we
detect absorption lines from both low- and high-ionization species from which
we deduce a metallicity, Z~0.06 Z_solar, with a depletion pattern that is
roughly similar to that of the Galactic warm halo, warm disk, or disk+halo.
More importantly, we detect strong absorption from SiII* indicating a dense
environment, n_H>10^2 cm^-3, in the vicinity of the burst, with a size of about
4 pc. In addition, the CIV absorption system spans a velocity range of about
1000 km/s, which is not detected in any other absorption feature. We show that
the most likely interpretation for this wide velocity range is absorption in
the wind from the progenitor star. In this context, the lack of corresponding
SiIV absorption indicates that the progenitor had a mass of <25 M_solar and a
metallicity <0.1 Z_solar, and therefore required a binary companion to eject
its hydrogen envelope prior to the GRB explosion. Finally, by extending the
GRB-DLA sample to z~4.3 we show that these objects appear to follow a similar
metallicity-redshift relation as in QSO-DLAs, but with systematically higher
metallicities. It remains to be seen whether this trend is simply due to the
higher neutral hydrogen columns in GRB-DLAs, or if it is a manifestation of
different star formation properties in GRB-DLAs. [abridged]


title:
On the interpretation of the spectral--energy correlations in long
  Gamma--Ray Bursts

abstract:
  Recently, Liang & Zhang (2005) found a tight correlation involving only
observable quantities, namely the isotropic emitted energy $E_{\gamma,iso}$,
the energy of the peak of the prompt spectrum $E^\prime_{p}$, and the jet break
time $t^\prime_{j}$. This phenomenological correlation can have a first
explanation in the framework of jetted fireballs, whose semiaperture angle
$\theta_{j}$ is measured by the jet break time $t^\prime_{j}$. By correcting
$E_{\gamma, iso}$ for the angle $\theta_{j}$ one obtains the so called
Ghirlanda correlation linking the collimation corrected energy $E_\gamma$ and
$E^\prime_{p}$. There are two ways to derive $\theta_{j}$ from $t^\prime_{j}$
in the standard scenario, corresponding to an homogeneous or to a wind-like
circumburst medium. We show that the Ghirlanda correlation with a wind-like
medium is as tight as (if not tighter) than the Ghirlanda correlation found in
the case of an homogeneous medium. There are hence two Ghirlanda correlations,
both entirely consistent with the phenomenological Liang & Zhang relation. We
consider the difference between the observed correlations and the ones one
would see in the comoving frame (i.e. moving with the same bulk Lorentz factor
of the fireball). Since both $E_{p}$ and $E_\gamma$ transform in the same way,
the wind-like Ghirlanda relation, which is linear, remains linear also in the
comoving frame, no matter the distribution of bulk Lorentz factors. Instead, in
the homogeneous density case, one is forced to assume the existence of a strict
relation between the bulk Lorentz factor and the total energy, which in turn
put constraints on the radiation mechanisms of the prompt emission. The
wind-like Ghirlanda correlation, being linear, corresponds to different bursts
having the same number of photons.