title:
New evidence for a linear colour-magnitude relation and a single
  Schechter function for red galaxies in a nearby cluster of galaxies down to
  M*+8

abstract:
  The colour and luminosity distributions of red galaxies in the cluster Abell
1185 (z=0.0325) were studied down to M*+8 in the B, V and R bands. The
colour-magnitude (hereafter CM) relation is linear without evidence for a
significant bending down to absolute magnitudes which are seldom probed in
literature (M_R=-12.5 mag). The CM relation is thin (+/-0.04 mag) and its
thickness is quite independent from the magnitude. The luminosity function of
red galaxies in Abell 1185 is adequately described by a Schechter function,
with a characteristic magnitude and a faint end slope that also well describe
the LF of red galaxies in other clusters. There is no passband dependency of
the LF shape other than an obvious M* shift due to the colour of the considered
population. Finally, we conclude that, based on colours and luminosity, red
galaxies form an homogeneous population over four decades in stellar mass,
providing a second evidence against faint red galaxies being a recent cluster
population.


title:
VI Photometry of Globular Clusters NGC6293 and NGC6541: The Formation of
  the Metal-Poor Inner Halo Globular Clusters

abstract:
  We present VI photometry of the metal-poor inner halo globular clusters
NGC6293 and NGC6541 using the planetary camera of the WFPC2 on board HST. Our
color-magnitude diagrams of the clusters show well-defined BHB populations,
consistent with their low metallicities and old ages. NGC6293 appears to have
blue straggler stars in the cluster's central region. We discuss the
interstellar reddening and the distance modulus of NGC6293 and NGC6541 and
obtain E(B-V) = 0.40 and (m-M)_0 = 14.61 for NGC6293 and E(B-V) = 0.14 and
(m-M)_0 = 14.19 for NGC6541. Our results confirm that NGC6293 and NGC6541 are
clearly located in the Galaxy's central regions (R_{GC} < 3 kpc). We also
discuss the differential reddening across NGC6293. The interstellar reddening
value of NGC6293 appears to vary by Delta E(B-V) ~ 0.02 -- 0.04 mag within our
small field of view.
  The most notable result of our study is that the inner halo clusters NGC6293
and NGC6541 essentially have the same ages as M92, confirming the previous
result from the HST NIC3 observations of NGC6287.


title: Most Detects G- and P-Modes in the B Supergiant HD 163899 (B2Ib/II)

abstract:
  The {\it Microvariability and Oscillations of Stars (MOST)} satellite
observed the B supergiant HD 163899 (B2 Ib/II) for 37 days as a guide star and
detected 48 frequencies $\la$ 2.8 c d$^{-1}$ with amplitudes of a few
milli-magnitudes (mmag) and less. The frequency range embraces g- and p-mode
pulsations. It was generally thought that no g-modes are excited in less
luminous B supergiants because strong radiative damping is expected in the
core. Our theoretical models, however, show that such g-modes are excited in
massive post-main-sequence stars, in accordance with these observations. The
nonradial pulsations excited in models between $20M_\odot$ at $\log T_{\rm eff}
\approx 4.41$ and $15M_\odot$ at $\log T_{\rm eff} \approx 4.36$ are roughly
consistent with the observed frequency range. Excitation by the Fe-bump in
opacity is possible because g-modes can be partially reflected at a convective
zone associated with the hydrogen-burning shell, which significantly reduces
radiative damping in the core. The {\it MOST} light curve of HD 163899 shows
that such a reflection of g-modes actually occurs, and reveals the existence of
a previously unrecognized type of variable, slowly pulsating B supergiants
(SPBsg) distinct from $\alpha$ Cyg variables. Such g-modes have great potential
for asteroseismology.


title: A model for the infrared emission of FSC 10214+4724

abstract:
  A model for the infrared emission of the high redshift ultraluminous infrared
galaxy FSC 10214+4724 is presented. The model assumes three components of
emission: a dusty torus viewed edge-on, clouds that are associated with the
narrow-line region and a highly obscured starburst. It is demonstrated that the
presence of clouds in the narrow-line region, with a covering factor of 17%,
can explain why the mid-infrared spectrum of FSC 10214+4724 shows a silicate
feature in emission despite the fact that its torus is viewed edge-on. It is
also shown that the same model, but with the torus viewed face-on, predicts a
spectrum with silicate emission features that is characteristic of the spectra
of quasars recently observed with Spitzer.


title: The Einstein Ring 0047-2808 Revisited: A Bayesian Inversion

abstract:
  In a previous paper, we outlined a new Bayesian method for inferring the
properties of extended gravitational lenses, given data in the form of resolved
images. This method holds the most promise for optimally extracting information
from the observed image, whilst providing reliable uncertainties in all
parameters. Here, we apply the method to the well studied optical Einstein ring
0047-2808. Our results are in broad agreement with previous studies, showing
that the density profile of the lensing galaxy is aligned within a few degrees
of the light profile, and suggesting that the source galaxy (at redshift 3.6)
is a binary system, although its size is only of order 1-2 kpc. We also find
that the mass of the elliptical lensing galaxy enclosed by the image is
(2.91$\pm$0.01)$\times10^{11}$ M$_{\sun}$. Our method is able to achieve
improved resolution for the source reconstructions, although we also find that
some of the uncertainties are greater than has been found in previous analyses,
due to the inclusion of extra pixels and a more general lens model.


title: Masses and angular momenta of contact binary stars

abstract:
  Results are presented on component masses and system angular momenta for over
a hundred low-temperature contact binaries. It is found that the secondary
components in close binary systems are very similar in mass. Our observational
evidence strongly supports the argument that the evolutionary process goes from
near-contact binaries to A-type contact binaries, without any need of mass loss
from the system. Furthermore, the evolutionary direction of A-type into W-type
systems with a simultaneous mass and angular momentum loss is also discussed.
The opposite direction of evolution seems to be unlikely, since it requires an
increase of the total mass and the angular momentum of the system.


title:
Simulations of Galactic Cosmic Rays Impacts on the Herschel/PACS
  Photoconductor Arrays with Geant4 Code

abstract:
  We present results of simulations performed with the Geant4 software code of
the effects of Galactic Cosmic Ray impacts on the photoconductor arrays of the
PACS instrument. This instrument is part of the ESA-Herschel payload, which
will be launched in late 2007 and will operate at the Lagrangian L2 point of
the Sun-Earth system. Both the Satellite plus the cryostat (the shield) and the
detector act as source of secondary events, affecting the detector performance.
Secondary event rates originated within the detector and from the shield are of
comparable intensity. The impacts deposit energy on each photoconductor pixel
but do not affect the behaviour of nearby pixels. These latter are hit with a
probability always lower than 7%. The energy deposited produces a spike which
can be hundreds times larger than the noise. We then compare our simulations
with proton irradiation tests carried out for one of the detector modules and
follow the detector behaviour under 'real' conditions.


title: Properties of Galactic B supergiants

abstract:
  Physical and wind properties of Galactic B supergiants are presented based
upon non-LTE line blanketed model atmospheres, including Sher 25 toward the NGC
3603 cluster. We compare Halpha derived wind densities with recent results for
SMC B supergiants and generally confirm theoretical expectations for stronger
winds amongst Galactic supergiants. Mid B supergiant winds are substantially
weaker than predictions from current radiatively driven wind theory, a problem
which is exacerbated if winds are already clumped in the Halpha line forming
region. We find that the so-called `bistability jump' at B1 (Teff ~ 21kK) from
Lamers et al. is rather a more gradual downward trend. CNO elemental
abundances, including Sher 25, reveal partially processed material at their
surfaces. In general, these are in good agreement with evolutionary predictions
for blue supergiants evolving redward accounting for rotational mixing. A few
cases, including HD 152236 (zeta^1 Sco), exhibit strongly processed material
which is more typical of Luminous Blue Variables. Our derived photospheric
[N/O] ratio for Sher~25 agrees with that for its ejecta nebula, although a
higher degree of CNO processing would be expected if the nebula originated
during a red supergiant phase, as is suspected for the ring nebula ejected by
the B supergiant progenitor of SN 1987A, Sk-69 202. Sher 25 has an inferred age
of ~5Myr in contrast with ~2Myr for HD 97950, the ionizing cluster of NGC 3603.
Sher 25 may be a foreground object or close binary evolution could be
responsible for its unusual location in the H-R diagram.


title: AL 3 (BH 261): a new globular cluster in the Galaxy

abstract:
  AL~3 (BH 261), previously classified as a faint open cluster candidate, is
shown to be a new globular cluster in the Milky Way, by means of B, V and I
Color-Magnitude Diagrams. The main feature of AL~3 is a prominent blue extended
Horizontal Branch. Its Color-Magnitude Diagrams match those of the intermediate
metallicity cluster M~5. The cluster is projected in a rich bulge field, also
contaminated by the disk main sequence. The globular cluster is located in the
Galactic bulge at a distance from the Sun d$_{\odot}$ = 6.0$\pm$0.5 kpc. The
reddening is E(B-V)=0.36$\pm$0.03 and the metallicity is estimated to be [Fe/H]
$\approx$ -1.3$\pm$0.25. AL~3 is probably one of the least massive globular
clusters of the Galaxy.


title:
On a systematic bias in SBF-based distances due to gravitational
  microlensing

abstract:
  The effect of gravitational microlensing on the determination of
extragalactic distances using surface brightness fluctuations (SBF) technique
is considered and a method to calculate SBF amplitudes in presence of
microlensing is presented. With a simple approximation for the magnification
power spectrum at low optical depth the correction to the SBF-based luminosity
distance is calculated. The results suggest the effect can be safely neglected
at present but may become important for SBF-based Hubble diagrams at luminosity
distances of about 1 Gpc and beyond.


title:
The superimposed photospheric and stellar wind variability of the O-type
  supergiant alpha Cam

abstract:
  (Abridged) We provide empirical constraints on the different physical
components that can act to yield temporal variability in predominantly or
partially wind-formed optical lines of luminous OB stars, and thus potentially
affect the reliable determination of fundamental parameters, including
mass-loss rates via clumped winds. Using time-series spectroscopy from epochs
spread over $\sim$ 4 years, a case study of the O9.5 supergiant $\alpha$ Cam is
presented. We demonstrate that the He I 5876 (2$^3$P$^0$--3$^3$D) line is an
important diagnostic for photospheric and wind variability in this star. The
optical line profiles of $\alpha$ Cam are affected by (i) deep-seated
fluctuations close to, or at, the photosphere, (ii) atmospheric velocity
gradients, and (iii) large-scale stellar wind structure. This study provides
new empirical perspectives on accurate line-synthesis modelling of stellar wind
signatures in massive luminous stars. Using a pure Halpha line-synthesis code
we interpret maximum changes in the red-ward and peak emission of $\alpha$ Cam
in terms of mass-loss rate differences in the range $\sim$ 5.1 $\times$
10$^{-6}$ to 6.5 $\times$ 10$^{-6}$ M$_\odot$ yr$^{-1}$. However, the models
generally fail to reproduce the morphology of blueward (possibly absorptive)
regions of the profiles.


title:
Global optical/infrared - X-ray correlations in X-ray binaries:
  quantifying disc and jet contributions

abstract:
  The optical/near-infrared (OIR) region of the spectra of low-mass X-ray
binaries appears to lie at the intersection of a variety of different emission
processes. In this paper we present quasi-simultaneous OIR - X-ray observations
of 33 XBs in an attempt to estimate the contributions of various emission
processes in these sources, as a function of X-ray state and luminosity. A
global correlation is found between OIR and X-ray luminosity for low-mass black
hole candidate XBs (BHXBs) in the hard X-ray state, of the form L_OIR is
proportional to Lx^0.6. This correlation holds over 8 orders of magnitude in Lx
and includes data from BHXBs in quiescence and at large distances (LMC and
M31). A similar correlation is found in low-mass neutron star XBs (NSXBs) in
the hard state. For BHXBs in the soft state, all the near-infrared (NIR) and
some of the optical emission is suppressed below the correlation, a behaviour
indicative of the jet switching off/on in transition to/from the soft state. We
compare these relations to theoretical models of a number of emission
processes. We find that X-ray reprocessing in the disc and emission from the
jets both predict a slope close to 0.6 for BHXBs, and both contribute to the
OIR in BHXBs in the hard state, the jets producing ~90 percent of the NIR
emission at high luminosities. X-ray reprocessing dominates the OIR in NSXBs in
the hard state, with possible contributions from the jets (only at high
luminosity) and the viscously heated disc. We also show that the optically
thick jet spectrum of BHXBs extends to near the K-band. (abridged)


title:
XMM-Newton observation of a spectral state transition in the peculiar
  radio/X-ray/gamma-ray source LS I +61 303

abstract:
  We report the results of XMM-Newton and BeppoSAX observations of the radio
and X-ray emitting star LS I +61 303, likely associated with the gamma-ray
source 2CG 135+01 and recently detected also at TeV energies. The data include
a long XMM-Newton pointing carried out in January 2005, which provides the
deepest look ever obtained for this object in the 0.3-12 keV range. During this
observation the source flux decreased from a high level of 13E12 erg/cm2/s to
4E12 erg/cm2/s within 2-3 hours.This flux range is the same seen in shorter and
less sensitive observations carried out in the past, but the new data show for
the first time that transitions between the two levels can occur on short time
scales. The flux decrease was accompanied by a significant softening of the
spectrum, which is well described by a power law with photon index changing
from 1.62+/-0.1 to 1.83+/-0.1. A correlation between hardness and intensity is
also found when comparing different short observations spanning almost 10 years
and covering various orbital phases.LS I +61 303 was detected in the 15-70 keV
range with the PDS instrument in one of the BeppoSAX observations, providing
evidence for variability also in the hard X-ray range. The X-ray spectra,
discussed in the context of multiwavelength observations, place some
interesting constraints on the properties and location of the high-energy
emitting region.


title: El Roque de Los Muchachos site characteristics, I.Temperature analysis

abstract:
  In this paper we present an analysis of temperature taken at two telescopes
located at the Observatorio del Roque de Los Muchachos in the Canary Islands.
More than 20 years of measurements at CAMC are included. The analysis of the
data from TNG and CAMC are compared in order to check local variations and long
term trends. Furthermore, the temperatures at different heights are correlated
to the quality of astronomical seeing. We considered the correlation of NAO
Index and annual downtime with mean annual temperatures. The final aim of this
work is to better understand the influence of wide scale parameters on local
meteorological data. The analysis is done using a statistical approach. From
each long series of data we compute the hourly averages and than the monthly
averages in order to reduce the short time fluctuations due to the day/night
cycle. A particular care is used to minimize any effect due to biases in case
of lacking of data. Finally, we compute the annual average from the monthly
ones. The two telescopes show similar trends. There is an increase of
temperatures of about 1.0 deg/10yrs from the annual means and a more rapid
increase of the annual minimums then the maximums. We found that positive NAO
Index reduces the increase of temperatures, and accelerates the decrease.
Moreover, there is no evidence that positive NAO Index corresponds to a lower
number of non-observable nights. Finally, seeing deteriorates when the gradient
of temperatures between 2 and 10 m above the ground is greater than -0.6 deg.


title:
Semi-empirical analysis of Sloan Digital Sky Survey galaxies III. How to
  distinguish AGN hosts

abstract:
  We consider the techniques to distinguish normal star forming (NSF) galaxies
and active galactic nuclei (AGN) hosts using optical spectra. The observational
data base is a set of 20000 galaxies extracted from the Sloan Digital Sky
Survey, for which we have determined the emission line intensities after
subtracting the stellar continuum obtained from spectral synthesis. Our
analysis is based on photoionization models computed using the stellar ionizing
radiation predicted by Starburst 99 and, for the AGNs, a broken power-law
spectrum. We explain why, among the four classical emission line diagnostic
diagrams, the [OIII]/Hb vs [NII]/Ha one works best. We show however, that none
of these diagrams is efficient in detecting AGNs in metal poor galaxies, should
such cases exist. We propose a new divisory line between ``pure'' NSF galaxies
and AGN hosts. We also show that a classification into NSF and AGN galaxies
using only [NII]/Ha is feasible and useful. Finally, we propose a new
classification diagram, the DEW diagram, plotting D_n(4000) vs
max(EW[OII],EW[NeIII]). This diagram can be used with optical spectra for
galaxies with redshifts up to z = 1.3, meaning an important progress over
classifications proposed up to now. Since the DEW diagram requires only a small
range in wavelength, it can also be used at even larger redshifts in suitable
atmospheric windows. It also has the advantage of not requiring stellar
synthesis analysis to subtract the stars and of allowing one to see ALL the
galaxies in the same diagram, including passive galaxies.


title:
The metallicity dependence of the long-duration GRB rate from host
  galaxy luminosities

abstract:
  We investigate the difference between the host galaxy properties of
core-collapse supernovae and long-duration gamma-ray bursts (LGRBs), and
quantify a possible metallicity dependence of the efficiency of producing
LGRBs. We use a sample of 16 CC SNe and 16 LGRBs from Fruchter et al. (2006)
which have similar redshift distributions to eliminate galaxy evolution biases.
We make a forward prediction of their host galaxy luminosity distributions from
the overall cosmic metallicity distribution of star formation. This appoach is
supported by the finding that LGRB hosts follow the L-Z relations of
star-forming galaxies. We then compare predictions for metallicity-dependent
event efficiencies with the observed host data. We find that UV-based SFR
estimates predict the hosts distribution of CC SNe perfectly well in a
metallicity-independent form. In contrast, LGRB hosts are fainter on average by
one magnitude, almost as faint as the Large Magellanic Cloud. Assuming this is
a metallicity effect, the present data are insufficient to discriminate between
a sharp metallicity cutoff and a soft decrease in efficiency towards higher
metallicity. For a sharp cut-off, however, we find a best value for the cutoff
metallicity, as reflected in the oxygen abundance, 12+log (O/H)_lim ~ 8.7+/-0.3
at 95% confidence including systematic uncertainties on the calibration of
Kobulnicky & Kewley (2004). This value is somewhat lower than the traditionally
quoted value for the Sun, but is comparable to the revised solar oxygen
abundance (Asplund, Grevesse & Sauval 2005). LGRB models that require sharp
metallicity cutoffs well below ~1/2 the revised solar metallicity appear to be
effectively ruled out (abridged).


title: Planetesimal Capture in the Disk Instability Model

abstract:
  We follow the contraction and evolution of a typical Jupiter-mass clump
created by the disk instability mechanism, and compute the rate of planetesimal
capture during this evolution. We show that such a clump has a slow contraction
phase lasting ~3x10^5 years. By following the trajectories of planetesimals as
they pass through the envelope of the protoplanet, we compute the cross-section
for planetesimal capture at all stages of the protoplanet's evolution. We show
that the protoplanet can capture a large fraction of the solid material in its
feeding zone, which will lead to an enrichment of the protoplanet in heavy
elements. The exact amount of this enrichment depends upon, but is not very
sensitive to the size and random speed of the planetesimals.


title: HD 65949: The Highest Known Mercury Excess Of Any CP Star?

abstract:
  ESO spectra of HD 65949 show it to be unlike any of the well-known types
within its temperature range $\approx$ 13600K. It is neither a silicon, nor a
mercury-manganese star, though it has a huge Hg II line at $\lambda$3984. We
estimate $\log({\rm Hg/H}) + 12.0 \approx 7.4$. This is higher than any
published stellar mercury abundance. HD 65949 is a member of a nearby open
cluster, NGC 2516, which is only slightly older than the Pleiades, and has been
of recent interest because of its numerous X-ray emission stars, including HD
65949 itself, or a close companion. A longitudinal magnetic field of the order
of -290 Gauss at the 4.7~$\sigma$ level was very recently diagnosed from
accurate circular spectropolarimetric observations with FORS 1 at the VLT.
  The spectral lines are sharp, allowing a thorough identification study.
Second spectra of Ti, Cr, and Fe are rich. Mn II is well identified but not
unusually strong. Numerous lines of S II and P II are found, but not Ga II. The
resonance lines of Sr II are strong. While many Y II lines are identified, and
Nb II is very likely present, {\it no} Zr II lines were found. Xe II is well
identified. Strong absorptions from the third spectra of the lanthanides Pr,
Nd, and Ho are present, but lines from the second spectra of lanthanides are
extremely weak or absent. Among lines from the heavier elements, those of Pt II
are clearly present, and the heaviest isotope, $^{198}$Pt, is indicated. The
uncommon spectrum of Re II is certain, while Os II and Te II are highly
probable. Several of the noted anomalies are unusual for a star as hot as HD
65949.


title: The stellar halo and outer disk of M33

abstract:
  We present first results from a Keck/DEIMOS spectroscopic survey of red giant
branch (RGB) stars in M33. The radial velocity distributions of the stars in
our fields are well described by three Gaussian components, corresponding to a
candidate halo component with an uncorrected radial velocity dispersion of
sigma ~ 50km/s, a candidate disk component with a dispersion sigma ~ 16km/s,
and a third component offset from the disk by ~ 50km/s, but for which the
dispersion is not well constrained. By comparing our data to a model of M33
based upon its HI rotation curve, we find that the stellar disk is offset in
velocity by ~ 25km/s from the HI disk, consistent with the warping which exists
between these components. The spectroscopic metallicity of the halo component
is [Fe/H] ~ -1.5, significantly more metal-poor than the implied metallicity of
the disk population ([Fe/H] ~ -0.9), which also has a broader colour dispersion
than the halo population. These data represent the first detections of
individual stars in the halo of M33 and, despite being ~ 10 times less massive
than M31 or the Milky Way, all three of these disk galaxies have stellar halo
components with a similar metallicity. The color distribution of the third
component is different to the disk and the halo, but is similar to that
expected for a single, coeval, stellar population, and could represent a
stellar stream. More observations are required to determine the true nature of
this intriguing third kinematic component in M33.


title:
Global MHD simulations of stratified and turbulent protoplanetary discs.
  I. Model properties

abstract:
  We present the results of global 3-D MHD simulations of stratified and
turbulent protoplanetary disc models. The aim of this work is to develop thin
disc models capable of sustaining turbulence for long run times, which can be
used for on-going studies of planet formation in turbulent discs. The results
are obtained using two codes written in spherical coordinates: GLOBAL and
NIRVANA. Both are time--explicit and use finite differences along with the
Constrained Transport algorithm to evolve the equations of MHD. In the presence
of a weak toroidal magnetic field, a thin protoplanetary disc in hydrostatic
equilibrium is destabilised by the magnetorotational instability (MRI). When
the resolution is large enough (25 vertical grid cells per scale height), the
entire disc settles into a turbulent quasi steady-state after about 300 orbits.
Angular momentum is transported outward such that the standard alpha parameter
is roughly 4-6*10^{-3}. We find that the initial toroidal flux is expelled from
the disc midplane and that the disc behaves essentially as a quasi-zero net
flux disc for the remainder of the simulation. As in previous studies, the disc
develops a dual structure composed of an MRI--driven turbulent core around its
midplane, and a magnetised corona stable to the MRI near its surface. By
varying disc parameters and boundary conditions, we show that these basic
properties of the models are robust. The high resolution disc models we present
in this paper achieve a quasi--steady state and sustain turbulence for hundreds
of orbits. As such, they are ideally suited to the study of outstanding
problems in planet formation such as disc--planet interactions and dust
dynamics.


title: Hickson 62.I. Kinematics of NGC4778

abstract:
  Detailed studies of the photometric and kinematical properties of compact
groups of galaxies are crucial to understand the physics of galaxy interactions
and to shed light on some aspects of galaxy formation and evolution. In this
paper we present a kinematical and photometrical study of a member, NGC4778, of
the nearest (z=0.0137) compact group: Hickson 62.
  Aims: The aim of this work was to investigate the existence of kinematical
anomalies in the brightest group member, NGC4778 in order to constrain the
dynamical status and the formation history of the group.
  Methods: We used long-slit spectra obtained with FORS1 at VLT, to measure
line-of-sight velocity distributions by means of the Fourier Correlation
Quotient method, and to derive the galaxy rotation curve and velocity
dispersion profile.
  Results: Our analysis reveals that Hickson 62a, also known as NGC4778, is an
S0 galaxy with kinematical and morphological peculiarities, both in its central
regions (r < 5'') and in the outer halo. In the central regions, the rotation
curve shows the existence of a kinematically decoupled stellar component,
offset with respect to the photometric center. In the outer halo we find an
asymmetric rotation curve and a velocity dispersion profile showing a rise on
the SW side, in direction of the galaxy NGC4776.
  Conclusions: The nuclear counterrotation, the distorted kinematics in the
outer halo and the X-ray properties of the group suggest that NGC4778 may be
the product of a recent minor merger, more reliable with a small late-type
galaxy.


title:
Towards observational constraints on negative (1+z)^4 type contribution
  in the Friedmann equation

abstract:
  We discuss certain issues related to the limitations of density parameters
for a ``radiation''-like contribution to the Friedmann equation using
kinematical or geometrical measurements. We analyse the observational
constraint of a negative $(1+z)^4$-type contribution in cosmological models. We
argue that it is not possible to determine the energy densities of individual
components of matter scaling like radiation from astronomical observations. We
find three different interpretations of the presence of the radiation term: 1)
the FRW universe filled with a massless scalar field in a quantum regime (the
Casimir effect), 2) the Friedmann-Robertson-Walker (FRW) model in the Randall
Sundrum scenario with dark radiation, 3) the cosmological model with global
rotation. From supernovae type Ia (SNIa) data, Fanaroff-Riley type IIb (FRIIb)
radio galaxy (RG) data, baryon oscillation peak and cosmic microwave background
radiation (CMBR) observations we obtain bounds for the negative radiation-like
term. A small negative contribution of dark radiation can reconcile the tension
in nucleosynthesis and remove also the disagreement between $H_0$ values
obtained from both SNIa and the Wilkinson Microwave Anisotropy Probe (WMAP)
satellite data.


title: Chandra X-Ray Observatory Observations of Neutron Stars: An Overview

abstract:
  We present a brief review of Chandra X-ray Observatory observations of
neutron stars. The outstanding spatial and spectral resolution of this great
observatory have allowed for observations of unprecedented clarity and
accuracy. Many of these observations have provided new insights into neutron
star physics. We present an admittedly biased and overly brief overview of
these observations, highlighting some new discoveries made possible by the
Observatory's unique capabilities. We also include our analysis of recent
multiwavelength observations of the putative pulsar and its pulsar-wind nebula
in the IC 443 SNR.


title:
Characteristics of proposed 3 and 4 telescope configurations for Darwin
  and TPF-I

abstract:
  The Darwin and TPF-I missions are Infrared free flying interferometer
missions based on nulling interferometry. Their main objective is to detect and
characterize other Earth-like planets, analyze the composition of their
atmospheres and their capability to sustain life, as we know it. Darwin and
TPF-I are currently in study phase. A number of mission architectures of 3 and
4 free flying telescopes are evaluated on the basis of the interferometer's
response, ability to distinguish multiple planet signatures and starlight
rejection capabilities. The characteristics of the new configurations are
compared also to the former, more complex Bowtie baseline architectures as well
as evaluated on base of their science capability.


title:
CCD Photometry of the globular cluster M2. RR Lyrae physical parameters
  and new variables

abstract:
  We report the results of CCD V and R photometry of the RR Lyrae stars in M2.
The periodicities of most variables are revised and new ephemerides are
calculated. Light curve decomposition of the RR Lyrae stars was carried out and
the corresponding mean physical parameters [Fe/H] = -1.47, Teff = 6276 K, log L
= 1.63 Lsun and Mv = 0.71 from nine RRab and [Fe/H] = -1.61, M = 0.54 Msun,
Teff = 7215 K, log L = 1.74 Lsun and Mv = 0.71 from two RRc stars were
calculated. A comparison of the radii obtained from the above luminosity and
temperature with predicted radii from nonlinear convective models is discussed.
The estimated mean distance to the cluster is 10.49 +- 0.15 kpc. These results
place M2 correctly in the general globular cluster sequences Oosterhoff type,
mass, luminosity and temperature, all as a function of the metallicity. Mean
relationships for M, log L/Lsun, Teff and Mv as a function of [Fe/H] for a
family of globular clusters are offered. These trends are consistent with
evolutionary and structural notions on the horizontal branch. Eight new
variables are reported.


title: Phantom Dark Energy Models with Negative Kinetic Term

abstract:
  We examine phantom dark energy models derived from a scalar field with a
negative kinetic term for which V(phi) approaches infinity asymptotically. All
such models can be divided into three classes, corresponding to an equation of
state parameter w with asymptotic behavior w -> -1, w -> w_0 < -1, and w ->
infinity. We derive the conditions on the potential V(phi) which lead to each
of these three types of behavior. For models with w -> -1, we derive the
conditions on V(phi) which determine whether or not such models produce a
future big rip. Observational constraints are derived on two classes of these
models: power-law potentials with V(phi) = lambda phi^alpha (with alpha
positive or negative) and exponential potentials of the form V(phi) = beta
e^{lambda phi^alpha}. It is shown that these models spend more time in a state
with Omega_m ~ Omega_phi than do corresponding models with a constant value of
w, thus providing a more satisfactory solution to the coincidence problem.


title: The signature of 44Ti in Cassiopeia A revealed by IBIS/ISGRI on INTEGRAL

abstract:
  We report the detection of both the 67.9 and 78.4 keV 44Sc gamma-ray lines in
Cassiopeia A with the INTEGRAL IBIS/ISGRI instrument. Besides the robustness
provided by spectro-imaging observations, the main improvements compared to
previous measurements are a clear separation of the two 44Sc lines together
with an improved significance of the detection of the hard X-ray continuum up
to 100 keV. These allow us to refine the determination of the 44Ti yield and to
constrain the nature of the nonthermal continuum emission. By combining
COMPTEL, BeppoSAX/PDS and ISGRI measurements, we find a line flux of (2.5 +/-
0.3)*10(-5) cm(-2) s(-1) leading to a synthesized 44Ti mass of 1.6
(+0.6-0.3)*10(-4) solar mass. This high value suggests that Cas A is peculiar
in comparison to other young supernova remnants, from which so far no line
emission from 44Ti decay has been unambiguously detected.


title: Cosmic Ray Scattering in Compressible Turbulence

abstract:
  We study the scattering of low-energy Cosmic Rays (CRs) in a turbulent,
compressive MHD fluid. We show that compressible MHD modes -- fast or slow
waves with wave lengths smaller than CR mean free paths induce cyclotron
instability in CRs. The instability feeds the new small-scale Alfvenic wave
component with wave vectors mostly along magnetic field, which is not a part of
the MHD turbulence cascade. This new component gives feedback on the
instability through decreasing the CR mean free path. We show that the ambient
turbulence fully suppresses the instability at large scales, while wave
steepening constrains the amplitude of the waves at small scales. We provide
the energy spectrum of the plane-parallel Alfvenic component and calculate mean
free paths of CRs as a function of their energy. We find that for the typical
parameters of turbulence in the interstellar medium and in the intercluster
medium the new Alfvenic component provides the scattering of the low energy CRs
that exceeds the direct resonance scattering by MHD modes. This solves the
problem of insufficient scattering of low-energy CRs in the turbulent
interstellar or intracluster medium that was reported in the literature.


title:
Neon Abundances in B-Stars of the Orion Association: Solving the Solar
  Model Problem?

abstract:
  We report on non-LTE Ne abundances for a sample of B-type stellar members of
the Orion Association. The abundances were derived by means of non-LTE fully
metal-blanketed model atmospheres and extensive model atoms with updated atomic
data. We find that these young stars have a very homogeneous abundance of A(Ne)
= 8.27 +/- 0.05. This abundance is higher by ~0.4 dex than currently adopted
solar value, A(Ne)=7.84, which is derived from lines produced in the corona and
active regions. The general agreement between the abundances of C, N, and O
derived for B stars with the solar abundances of these elements derived from
3-D hydrodynamical models atmospheres strongly suggests that the abundance
patterns of the light elements in the Sun and B stars are broadly similar. If
this hypothesis is true, then the Ne abundance derived here is the same within
the uncertainties as the value required to reconcile solar models with
helioseismological observations.


title:
The Masses of Nuclear Black Holes in Luminous Elliptical Galaxies and
  Implications for the Space Density of the Most Massive Black Holes

abstract:
  Black hole masses predicted from the Mbh-sigma relationship conflict with
those predicted from the Mbh-L relationship for the most luminous galaxies,
such as brightest cluster galaxies (BCGs). This is because stellar velocity
dispersion, sigma, increases only weakly with L for BCGs and other giant
ellipticals. The Mbh-L relationship predicts that the most luminous BCGs may
have Mbh approaching 10^{10}M_sol, while the M-sigma relationship always
predicts Mbh<3X10^9M_sol. We argue that the Mbh-L relationship is a plausible
or even preferred description for BCGs and other galaxies of similar
luminosity. If cores in central stellar density are formed by binary BHs, then
the inner-core cusp radius, r_gamma, may be an independent witness of Mbh.
Using structural parameters derived from a large sample of early-type galaxies
observed by HST, we argue that L is superior to sigma as an indicator of
r_gamma in luminous galaxies. The observed r_gamma-Mbh relationship for 11 core
galaxies with measured Mbh appears to be consistent with the Mbh-L relationship
for BCGs. BCGs have large cores appropriate for their large luminosities that
may be difficult to generate with the modest BH masses inferred from the
Mbh-sigma relationship. Mbh~L may be expected to hold for BCGs, if they were
formed in dissipationless mergers, which should preserve ratio of BH to stellar
mass. This picture appears to be consistent with the slow increase in sigma
with L and the more rapid increase in effective radii with L seen in BCGs. If
BCGs have large BHs commensurate with their luminosities, then the local BH
mass function for Mbh>3X10^9M_sol may be nearly an order of magnitude richer
than that inferred from the Mbh-sigma relationship. The volume density of QSOs
at earlier epochs may favor the predictions from the Mbh-L relationship.


title:
Spitzer IRS Spectra of Optically Faint Infrared Sources with Weak
  Spectral Features

abstract:
  Spectra have been obtained with the low-resolution modules of the Infrared
Spectrograph (IRS) on the Spitzer Space Telescope (Spitzer) for 58 sources
having f$_{\nu}$(24 micron) > 0.75 mJy. Sources were chosen from a survey of
8.2 deg$^{2}$ within the NOAO Deep Wide-Field Survey region in Bootes (NDWFS)
using the Multiband Imaging Photometer (MIPS) on the Spitzer Space Telescope.
Most sources are optically very faint (I > 24mag). Redshifts have previously
been determined for 34 sources, based primarily on the presence of a deep 9.7
micron silicate absorption feature, with a median z of 2.2. Spectra are
presented for the remaining 24 sources for which we were previously unable to
determine a confident redshift because the IRS spectra show no strong features.
Optical photometry from the NDWFS and infrared photometry with MIPS and the
Infrared Array Camera on the Spitzer Space Telescope (IRAC) are given, with K
photometry from the Keck I telescope for some objects. The sources without
strong spectral features have overall spectral energy distributions (SEDs) and
distributions among optical and infrared fluxes which are similar to those for
the sources with strong absorption features. Nine of the 24 sources are found
to have feasible redshift determinations based on fits of a weak silicate
absorption feature. Results confirm that the "1 mJy" population of 24 micron
Spitzer sources which are optically faint is dominated by dusty sources with
spectroscopic indicators of an obscured AGN rather than a starburst. There
remain 14 of the 58 sources observed in Bootes for which no redshift could be
estimated, and 5 of these sources are invisible at all optical wavelengths.


title:
Astrophysical Explosions Driven by a Rotating, Magnetized, Gravitating
  Sphere

abstract:
  We present the results of a numerical magnetohydrodynamic simulation that
demonstrates a mechanism by which magnetic fields tap rotational energy of a
stellar core and expel the envelope. Our numerical setup, designed to focus on
the basic physics of the outflow mechanism, consists of a solid, gravitating
sphere, which may represent the compact core of a star, surrounded by an
initially hydrostatic envelope of ionized gas. The core is threaded by a
dipolar magnetic field that also permeates the envelope. At the start of the
simulation, the core begins to rotate at 10% of the escape speed. The magnetic
field is sufficiently strong to drive a magneto-rotational explosion, whereby
the entire envelope is expelled, confirming the expectation of analytical
models. Furthermore, the dipolar nature of the field results in an explosion
that is enhanced simultaneously along the rotation axis (a jet) and along the
magnetic equator. While the initial condition is simplified, the simulation
approximates circumstances that may arise in astrophysical objects such as Type
II supernovae, gamma ray bursts, and proto-planetary nebulae.


title:
Deep shower interpretation of the cosmic ray events observed in excess
  of the Greisen-Zatsepin-Kuzmin energy

abstract:
  We consider the possibility that the ultra-high-energy cosmic ray flux has a
small component of exotic particles which create showers much deeper in the
atmosphere than ordinary hadronic primaries. It is shown that applying the
conventional AGASA/HiRes/Auger data analysis procedures to such exotic events
results in large systematic biases in the energy spectrum measurement. SubGZK
exotic showers may be mis-reconstructed with much higher energies and mimick
superGZK events. Alternatively, superGZK exotic showers may elude detection by
conventional fluorescence analysis techniques.


title:
The Sun's Journey Through the Local Interstellar Medium: The PaleoLISM
  and Paleoheliosphere

abstract:
  Over the recent past, the galactic environment of the Sun has differed
substantially from today. Sometime within the past ~130,000 years, and possibly
as recent as ~56,000 years ago, the Sun entered the tenuous tepid partially
ionized interstellar material now flowing past the Sun. Prior to that, the Sun
was in the low density interior of the Local Bubble. As the Sun entered the
local ISM flow, we passed briefly through an interface region of some type. The
low column densities of the cloud now surrounding the solar system indicate
that heliosphere boundary conditions will vary from opacity considerations
alone as the Sun moves through the cloud. These variations in the interstellar
material surrounding the Sun affected the paleoheliosphere.


title:
Neutrino Spectra from Low and High Luminosity Populations of Gamma Ray
  Bursts

abstract:
  The detection of GRB 060218 at z=0.033 by {\em Swift} within 1.5 years of
operation, together with the detection of GRB 980425 at $z=0.0085$ by BeppoSAX,
suggest that these low-luminosity (LL) GRBs have a much higher event rate than
the canonical high-luminosity (HL) GRBs, and they form a distinct new component
in the GRB luminosity function. We explore the contribution of this previously
neglected GRB population to the diffuse neutrino background within the internal
shock model and compare it with that of the canonical HL population. By
considering a wide range of distributions of various parameters (e.g.
luminosity, spectral break energy, duration, variability time, Lorentz factor,
redshift) for both populations, we find that although it is difficult to detect
neutrinos from the individual LL GRBs, the contribution of the LL population to
the diffuse neutrino background is more than the HL population above about
$10^{8}$ GeV.


title:
A close look into the carbon disk at the core of the planetary nebula
  CPD-568032

abstract:
  We present high spatial resolution observations of the dusty core of the
Planetary Nebula with Wolf-Rayet central star CPD-568032. These observations
were taken with the mid-infrared interferometer VLTI/MIDI in imaging mode
providing a typical 300 mas resolution and in interferometric mode using
UT2-UT3 47m baseline providing a typical spatial resolution of 20 mas. The
visible HST images exhibit a complex multilobal geometry dominated by faint
lobes. The farthest structures are located at 7" from the star. The mid-IR
environment of CPD-568032 is dominated by a compact source, barely resolved by
a single UT telescope in a 8.7 micron filter. The infrared core is almost fully
resolved with the three 40-45m projected baselines ranging from -5 to 51 degree
but smooth oscillating fringes at low level have been detected in spectrally
dispersed visibilities. This clear signal is interpreted in terms of a ring
structure which would define the bright inner rim of the equatorial disk.
Geometric models allowed us to derive the main geometrical parameters of the
disk. For instance, a reasonably good fit is reached with an achromatic and
elliptical truncated Gaussian with a radius of 97+/-11 AU, an inclination of
28+/-7 degree and a PA for the major axis at 345+/-7 degree. Furthermore, we
performed some radiative transfer modeling aimed at further constraining the
geometry and mass content of the disk, by taking into account the MIDI
dispersed visibilities, spectra, and the large aperture SED of the source.
These models show that the disk is mostly optically thin in the N band and
highly flared.


title:
CO Detection and Millimeter Continuum Emission from Low Surface
  Brightness Galaxies

abstract:
  We present BIMA and IRAM CO(1--0) observations of seven low surface
brightness (LSB) galaxies, including three large spirals with faint disks but
prominent bulges, and four relatively small LSB galaxies with irregular disks.
The giant LSB galaxies are UGC 5709, UGC 6614 and F568-6 (Malin2). The smaller
LSB galaxies are NGC 5585, UGC 4115, UGC 5209 and F583-1. The galaxies were
selected based on their relatively high metallicity and apparent signs of star
formation in their disks. The BIMA maps suggested the presence of molecular gas
in 2 of the giant LSB galaxies, F568-6 and UGC 6614. Using the 30m IRAM
telescope we detected CO (1--0) emission in the disks of both galaxies and in
the nucleus of F568-6. The molecular gas in these galaxies is clearly offset
from the nucleus and definitely associated with the LSB disk. In addition we
also detected a millimeter continuum source in the center of UGC 6614. When
compared with VLA 1.5 GHz observations of the galaxy, the emission was found to
have a flat spectrum indicating that the millimeter continuum emission is most
likely due to an active galactic nucleus (AGN) in the galaxy. Our results show
that giant LSB spirals may contain significant quantities of molecular gas in
their disks and also harbor radio bright AGN in their centers.


title:
Deep J-band imaging of high redshift QSO candidates with the Himalayan
  Chandra Telescope

abstract:
  High redshift QSOs (redshift$>$5.7) are highly important objects. If such
QSOs may be found, their spectra will reveal the onset of reionization of the
intergalactic medium (Gunn-Peterson trough), and provide precious insights into
the re-ionization epoch in the very early universe.
  Here we report our pilot attempt to follow-up high redshift QSOs with the
Himalayan Chandra Telescope.
  Deep $J$-band imaging was performed on three high redshift QSO candidates
color-selected from the SDSS, using the near-infrared imager. Although none of
the targets turned out to be likely high redshift QSOs, careful data reduction
shows that the data reach the required depth, proving that the Himalayan
Chandra Telescope is a powerful tool to follow-up high redshift QSO candidates.


title:
solarFLAG hare and hounds: on the extraction of rotational p-mode
  splittings from seismic, Sun-as-a-star data

abstract:
  We report on results from the first solar Fitting at Low-Angular degree Group
(solar FLAG) hare-and-hounds exercise. The group is concerned with the
development of methods for extracting the parameters of low-l solar p mode data
(`peak bagging'), collected by Sun-as-a-star observations. Accurate and precise
estimation of the fundamental parameters of the p modes is a vital
pre-requisite of all subsequent studies. Nine members of the FLAG (the
`hounds') fitted an artificial 3456-d dataset. The dataset was made by the
`hare' (WJC) to simulate full-disc Doppler velocity observations of the Sun.
The rotational frequency splittings of the l=1, 2 and 3 modes were the first
parameter estimates chosen for scrutiny. Significant differences were uncovered
at l=2 and 3 between the fitted splittings of the hounds. Evidence is presented
that suggests this unwanted bias had its origins in several effects. The most
important came from the different way in which the hounds modeled the
visibility ratio of the different rotationally split components. Our results
suggest that accurate modelling of the ratios is vital to avoid the
introduction of significant bias in the estimated splittings. This is of
importance not only for studies of the Sun, but also of the solar analogues
that will targets for asteroseismic campaigns.


title: Clusters in the solar neighbourhood: how are they destroyed?

abstract:
  We predict the survival time of initially bound star clusters in the solar
neighbourhood taking into account: (1) stellar evolution, (2) tidal stripping,
(3) shocking by spiral arms and (4) encounters with giant molecular clouds. We
find that the predicted dissolution time is t_dis= 1.7 (M_i/10^4 M_sun)^0.67
Gyr for clusters in the mass range of 10^2 < M_i < 10^5 M_sun, where
  M_i is the initial mass of the cluster.. The resulting predicted shape of the
logarithmic age distribution agrees very well with the empirical one, derived
from a complete sample of clusters in the solar neighbourhood within 600 pc.
The required scaling factor implies a star formation rate of 400 M_sun/Myr
within 600 pc from the Sun or a surface formation rate of 3.5 10^-10 M_sun/(yr
pc^2) for stars in bound clusters with an initial mass in the range of 10^2 to
3 10^4 M_sun.


title:
Probing the Proper Motion of the Central Compact Object in Puppis-A with
  the Chandra High Resolution Camera

abstract:
  By making use of the sub-arcsecond angular resolution of the High Resolution
Camera (HRC-I) aboard the Chandra X-ray satellite we have examined the central
compact object RX J0822-4300, in the supernova remnant Puppis-A for a possible
proper motion. Using data which span an epoch of 1952 days we found the
position of RX J0822-4300, different by $0.574\pm0.184$ arcsec, implying a
proper motion of $\mu=107.49\pm34.46$ mas/yr. For a distance of 2.2 kpc, this
proper motion is equivalent to a recoil velocity of $1121.79\pm 359.60$ km/s.
The position angle is found to be $241^\circ \pm 24^\circ$. Since both the
magnitude and direction of the proper motion are in agreement with the birth
place of RX J0822-4300, being near to the optical expansion center of the
supernova remnant, the result presented in this letter is a promising
indication of a fast moving compact object in a supernova remnant. Although the
positional shift inferred from the current data is significant at a
$\sim3\sigma$ level only, one or more future HRC-I observations can obtain a
much larger positional separation and further constrain the measurement.


title: Growth of galactic bulges by mergers. II. Low-density satellites

abstract:
  Satellite accretion events have been invoked for mimicking the internal
secular evolutionary processes of bulge growth. However, N-body simulations of
satellite accretions have paid little attention to the evolution of bulge
photometric parameters, to the processes driving this evolution, and to the
consistency of this evolution with observations. We want to investigate whether
satellite accretions indeed drive the growth of bulges, and whether they are
consistent with global scaling relations of bulges and discs. We perform N-body
models of the accretion of satellites onto disc galaxies. A Tully-Fisher (M
\propto V_{rot}^ {alpha_TF}) scaling between primary and satellite ensures that
density ratios, critical to the outcome of the accretion, are realistic. We
carry out a full structural, kinematic and dynamical analysis of the evolution
of the bulge mass, bulge central concentration, and bulge-to-disc scaling
relations. The remnants of the accretion have bulge-disc structure. Both the
bulge-to-disc ratio (B/D) and the Sersic index (n) of the remnant bulge
increase as a result of the accretion, with moderate final bulge Sersic
indices: n = 1.0 to 1.9. Bulge growth occurs no matter the fate of the
secondary, which fully disrupts for alpha_TF=3 and partially survives to the
remnant center for alpha_TF = 3.5 or 4. Global structural parameters evolve
following trends similar to observations. We show that the dominant mechanism
for bulge growth is the inward flow of material from the disc to the bulge
region during the satellite decay. The models confirm that the growth of the
bulge out of disc material, a central ingredient of secular evolution models,
may be triggered externally through satellite accretion.


title: Disc-Jet coupling in the LMXB 4U1636-53 from INTEGRAL

abstract:
  We report on the spectral analysis results of the neutron star, atoll type,
low mass X-ray Binary 4U1636-53 observed by INTEGRAL and BeppoSAX satellites.
Spectral behavior in three different epochs corresponding to three different
spectral states has been deeply investigated. Two data set spectra show a
continuum well described by one or two soft blackbody plus a Comptonized
components with changes in the Comptonizing electrons and black body
temperature and the accretion rates, which are typical of the spectral
transitions from high to low state. In one occasion INTEGRAL spectrum shows,
for first time in this source, a hard tail dominating the emission above 30
keV. The total spectrum is fitted as the sum of a Comptonized component similar
to soft state and a power-law component (Gamma=2.76), indicating the presence
of a non thermal electron distribution of velocities. In this case, a
comparison with hard tails detected in soft states from neutron stars systems
and some black hole binaries suggests that a similar mechanism could originate
these components in both cases.


title:
Supersonic turbulence in shock-bound interaction zones I: symmetric
  settings

abstract:
  Colliding hypersonic flows play a decisive role in many astrophysical
objects. In this paper, we look at the idealized model of a 2D plane parallel
isothermal slab (CDL) and at symmetric settings, where both flows have equal
parameters. We performed a set of high-resolution simulations with upwind Mach
numbers, 5 < M_u < 90.
  We find that the CDL is irregularly shaped and has a patchy and filamentary
interior. The size of these structures increases with l_cdl, the extension of
the CDL. On average, but not at each moment, the solution is about self-similar
and depends only on M_u. We find the root mean square Mach number to scale as
M_rms ~ 0.2 M_u. Independent of M_u is the mean density, rho_m ~ 30 rho_u. The
fraction f_eff of the upwind kinetic energy that survives shock passage scales
as f_eff= 1 - M_rms^(-0.6). This dependence persists if the upwind flow
parameters differ from one side to the other of the CDL, indicating that the
turbulence within the CDL and its driving are mutually coupled. In the same
direction points the finding that the auto-correlation length of the confining
shocks and the characteristic length scale of the turbulence within the CDL are
proportional.
  In summary, larger upstream Mach numbers lead to a faster expanding CDL with
more strongly inclined confining interfaces relative to the upstream flows,
more efficient driving, and finer interior structure relative to the extension
of the CDL.


title: Type I and Two-Gap Superconductivity in Neutron Star Magnetism

abstract:
  Neutron-star inner cores with several charged baryonic components are likely
to be analogues of the two-gap superconductor which is of current interest in
condensed-matter physics. Consequently, type I superconductivity is less
probable than type II but may nevertheless be present in some intervals of
matter density. The intermediate state structure formed at finite magnetic flux
densities after the superconducting transitions is subject to buoyancy,
frictional and neutron-vortex interaction forces. These are estimated and it is
shown that the most important frictional force is that produced by the stable
stratification of neutron-star matter, the irreversible process being diffusion
in the normal, finite magnetic-flux density, parts of the structure. The
length-scale of the structure, in directions perpendicular to the local
magnetic field is of crucial importance. For small scales, the flux comoves
with the neutron vortices, as do the proton vortices of a type II
superconductor. But for much larger length-scales, flux movement tends to that
expected for normal charged Fermi systems.


title: 3D MHD Simulations of Laboratory Plasma Jets

abstract:
  Jets and outflows are thought to be an integral part of accretion phenomena
and are associated with a large variety of objects. In these systems, the
interaction of magnetic fields with an accretion disk and/or a magnetized
central object is thought to be responsible for the acceleration and
collimation of plasma into jets and wider angle flows. In this paper we present
three-dimensional MHD simulations of magnetically driven, radiatively cooled
laboratory jets that are produced on the MAGPIE experimental facility. The
general outflow structure comprises an expanding magnetic cavity which is
collimated by the pressure of an extended plasma background medium, and a
magnetically confined jet which develops within the magnetic cavity. Although
this structure is intrinsically transient and instabilities in the jet and
disruption of the magnetic cavity ultimately lead to its break-up, a well
collimated, knotty jet still emerges from the system; such clumpy morphology is
reminiscent of that observed in many astrophysical jets. The possible
introduction in the experiments of angular momentum and axial magnetic field
will also be discussed.


title:
A Spitzer IRS Spectral Atlas of Luminous 8 micron Sources in the Large
  Magellanic Cloud

abstract:
  We present an atlas of Spitzer Space Telescope Infrared Spectrograph (IRS)
spectra of highly luminous, compact mid-infrared sources in the Large
Magellanic Cloud. Sources were selected on the basis of infrared colors and 8
micron (MSX) fluxes indicative of highly evolved, intermediate- to high-mass
stars with current or recent mass loss at large rates. We determine the
chemistry of the circumstellar envelope from the mid-IR continuum and spectral
features and classify the spectral types of the stars. In the sample of 60
sources, we find 21 Red Supergiants (RSGs), 16 C-rich Asymptotic Giant Branch
(AGB) stars, 11 HII regions, 4 likely O-rich AGB stars, 4 Galactic O-rich AGB
stars, 2 OH/IR stars, and 2 B[e] supergiants with peculiar IR spectra. We find
that the overwhelming majority of the sample AGB stars (with typical IR
luminosities ~1.0E4 L_sun) have C-rich envelopes, while the O-rich objects are
predominantly luminous RSGs with L_IR ~ 1.0E5 L_sun. We determine mean
bolometric corrections to the stellar K-band flux densities and find that for
carbon stars, the bolometric corrections depend on the infrared color, whereas
for RSGs, the bolometric correction is independent of IR color. Our results
reveal that objects previously classified as PNe on the basis of IR colors are
in fact compact HII regions with very red IRS spectra that include strong
atomic recombination lines and PAH emission features. We demonstrate that the
IRS spectral classes in our sample separate clearly in infrared color-color
diagrams that use combinations of 2MASS data and synthetic IRAC/MIPS fluxes
derived from the IRS spectra. On this basis, we suggest diagnostics to identify
and classify, with high confidence levels, IR-luminous evolved stars and HII
regions in nearby galaxies using Spitzer and near-infrared photometry.


title: Automated detection of gravitational arcs

abstract:
  This paper presents a method to identify gravitational arcs or more generally
elongated structures in a given image. The method is based on the computation
of a local estimator of the elongation. The estimation of the local elongation
proceed in two steps: first the local orientation of the structure is computed,
then in the next step, a rotation is performed, and the marginal distributions
are used to compute the elongation. This procedure allows the computation of
the local elongation at each point in the image. Then, using a threshold on the
elongation map the elongated structures are identified and re-constructed using
connectivity criteria. Finally a catalogue of elongated structures is produced,
and the properties of each object are computed, allowing the selection of
potential arc candidates. The final selection of the arc candidates is
performed by visual inspection of multi-color images of a small number of
objects. This method is a general tool that may be applied not only to
gravitational arcs, but to all problems related to the mapping and measurement
of elongated structures, in an image, or a volume.


title:
Chemical abundances for the transiting planet host stars OGLE-TR-10, 56,
  111, 113, 132 and TrES-1. Abundances in different galactic populations

abstract:
  We used the UVES spectrograph (VLT-UT2 telescope) to obtain high-resolution
spectra of 6 stars hosting transiting planets, namely for OGLE-TR-10, 56, 111,
113, 132 and TrES-1. The spectra are now used to derive and discuss the
chemical abundances for C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni,
Cu and Zn. Abundances were derived in LTE, using 1-D plane-parallel Kurucz
model atmospheres. For S, Zn and Cu we used a spectral synthesis procedure,
while for the remaining cases the abundances were derived from measurements of
line-equivalent widths. The resulting abundances are compared with those found
for stars in the solar neighborhood. Distances and galactic coordinates are
estimated for the stars. We conclude that besides being particularly
metal-rich, with small possible exceptions OGLE-TR-10, 56, 111, 113, 132 and
TrES-1 are chemically undistinguishable from the field (thin disk) stars
regarding their [X/Fe] abundances. This is particularly relevant for the most
distant of the targets, located at up to ~2 Kpc from the Sun. We also did not
find any correlation between the abundances and the condensation temperature of
the elements, an evidence that strong accretion of planetary-like material,
tentatively connected to planetary migration, did not occur.


title: Tight coupling expansion and fully inhomogeneous magnetic fields

abstract:
  The tight coupling expansion, appropriately generalized to include
large-scale magnetic fields, allows the estimate of the brightness
perturbations of CMB anisotropies for typical wavelengths that are larger than
the Hubble radius after matter-radiation equality. After discussing the basic
features of the the pre-decoupling initial conditions in the presence of fully
inhomogeneous magnetic fields, the tight coupling expansion is studied both
analytically and numerically. From the requirement that the amplitudes and
phases of Sakharov oscillations are (predominantly) adiabatic and from the
inferred value of the plateau in the temperature autocorrelation, the effects
of the magnetized contribution can be systematically investigated and
constrained.


title: Possible Application of Wavefront Coding to the LSST

abstract:
  Wavefront Coding has been applied as a means to increase the effective depth
of focus of optical systems. In this note I discuss the potential for this
technique to increase the depth of focus of the LSST and the resulting
advantages for the construction and operation of the facility, as well as
possible drawbacks. It may be possible to apply Wavefront Coding without
changing the current LSST design, in which case Wavefront Coding might merit
further study as a risk mitigation strategy.


title: An HST Archival Survey of Feathers in Spiral Galaxies

abstract:
  We present a survey of spiral arm extinction substructure referred to as
feathers in 223 spiral galaxies using HST WFPC2 images. The sample includes all
galaxies in the RC3 catalog with cz < 5000 km/s, B_T < 15, i < 60 degrees, and
types Sa--Sd with well-exposed broadband WFPC2 images. The detection frequency
of delineated, periodic feathers in this sample is 20% (45 of 223). This work
is consistent with Lynds (1970), who concluded that feathers are common in
prototypical Sc galaxies; we find that feathers are equally common in Sb
galaxies. Sb--Sc galaxies without clear evidence for feathers either had poorer
quality images, or flocculent or complex structure. We did not find clearly
defined feathers in any Scd--Sd galaxy. The probability of detecting feathers
was highest (83%) for spirals with well-defined primary dust lanes (PDLs; the
lanes which line the inner edge of an arm); well-defined PDLs were only noted
in Sab--Sc galaxies. Consistent with earlier work, we find that neighboring
feathers tend to have similar shapes and pitch angles. OB associations are
often found lining feathers, and many feathers transition to the stellar
substructures known as spurs (Elmegreen 1980). We find that feathers are
coincident with interarm filaments strikingly revealed in Spitzer 8 micron
images. Comparison with CO 1-0 maps of NGC 0628 and NGC 5194 from BIMA SONG
shows that feathers originate at the PDL coincident with gas surface density
peaks. Contrary to the appearance at 8 microns, the CO maps show that gas
surface density in feathers decreases rapidly with distance from the PDL. Also,
we find that the spacing between feathers decreases with increasing gas surface
density, consistent with formation via a gravitational instability.


title:
Interferometric Space Missions for the Search for Terrestrial
  Exoplanets: Requirements on the Rejection Ratio

abstract:
  The requirements on space missions designed to study Terrestrial exoplanets
are discussed. We then investigate whether the design of such a mission,
specifically the Darwin nulling interferometer, can be carried out in a
simplified scenario. The key element here is accepting somewhat higher levels
of stellar leakage. We establish detailed requirements resulting from the
scientific rationale for the mission, and calculate detailed parameters for the
stellar suppression required to achieve those requirements. We do this
utilizing the Darwin input catalogue. The dominating noise source for most
targets in this sample is essentially constant for all targets, while the
leakage diminishes with the square of the distance. This means that the stellar
leakage has an effect on the integration time only for the nearby stars, while
for the more distant targets its influence decreases significantly. We assess
the impact of different array configurations and nulling profiles and identify
the stars for which the detection efficiency can be maximized.


title:
When Do Internal Shocks End and External Shocks Begin? Early-Time
  Broadband Modelling of GRB 051111

abstract:
  Even with the renaissance in gamma-ray burst (GRB) research fostered by the
Swift satellite, few bursts have both contemporaneous observations at long
wavelengths and exquisite observations at later times across the
electromagnetic spectrum. We present here contemporaneous imaging with the KAIT
robotic optical telescope, dense optical sampling with Lulin, and supplemented
with infrared data from PAIRITEL and radio to gamma-ray data from the
literature. For the first time, we can test the constancy of microphysical
parameters in the internal-external shock paradigm and carefully trace the flow
of energy from the GRB to the surrounding medium. KAIT data taken <~1 minute
after the start of GRB051111 and coinciding with the fading gamma-ray tail of
the prompt emission indicate a smooth re-injection of energy into the shock. No
color change is apparent in observations beginning ~1.5 minutes after the GRB
and lasting for the first hour after the burst. There are achromatic flux
modulations about the best-fit model at late (t~10^4 s) times, possibly due to
variations in the external density. We find that the host-galaxy extinction is
well fit by a curve similar to that ofthe Small Magellanic Cloud. Low visual
extinction, A_V~0.2 mag, combined with high column densities determined from
the X-ray and optical spectroscopy (N_H> 10^21 cm^-2), indicate a low
dust-to-metals ratio and a possible over-abundance of the light metals. An
apparent small ratio of total to selective extinction (R_V~2) argues against
dust destruction by the GRB. Time constancy of both the IR/optical/UV spectral
energy distribution and the soft X-ray absorption suggests that the absorbing
material is not local to the GRB.


title: Models of mass segregation at the Galactic centre

abstract:
  We study the process of mass segregation through 2-body relaxation in
galactic nuclei with a central massive black hole (MBH). This study has bearing
on a variety of astrophysical questions, from the distribution of X-ray
binaries at the Galactic centre, to tidal disruptions of main-sequence and
giant stars, to inspirals of compact objects into the MBH, an important
category of events for the future space borne gravitational wave interferometer
LISA. In relatively small galactic nuclei, typical hosts of MBHs with masses in
the range 1e4-1e7 Msun, the relaxation induces the formation of a steep density
cusp around the MBH and strong mass segregation. Using a spherical stellar
dynamical Monte-Carlo code, we simulate the long-term relaxational evolution of
galactic nucleus models with a spectrum of stellar masses. Our focus is the
concentration of stellar black holes to the immediate vicinity of the MBH.
Special attention is given to models developed to match the conditions in the
Milky Way nucleus.


title:
Exoplanet detection with simultaneous spectral differential imaging:
  effects of out-of-pupil-plane optical aberrations

abstract:
  Imaging faint companions (exoplanets and brown dwarfs) around nearby stars is
currently limited by speckle noise. To efficiently attenuate this noise, a
technique called simultaneous spectral differential imaging (SSDI) can be used.
This technique consists of acquiring simultaneously images of the field of view
in several adjacent narrow bands and in combining these images to suppress
speckles. Simulations predict that SSDI can achieve, with the acquisition of
three wavelengths, speckle noise attenuation of several thousands. These
simulations are usually performed using the Fraunhofer approximation, i.e.
considering that all aberrations are located in the pupil plane. We have
performed wavefront propagation simulations to evaluate how out-of-pupil-plane
aberrations affect SSDI speckle noise attenuation performance. The Talbot
formalism is used to give a physical insight of the problem; results are
confirmed using a proper wavefront propagation algorithm. We will show that
near-focal-plane aberrations can significantly reduce SSDI speckle noise
attenuation performance at several lambda/D separation. It is also shown that
the Talbot effect correctly predicts the PSF chromaticity. Both differential
atmospheric refraction effects and the use of a coronagraph will be discussed.


title: Neutrino Astronomy at the South Pole

abstract:
  IceCube is currently being built deep in the glacial ice beneath the South
Pole. In its second year of construction, it is already larger than its
predecessor, AMANDA. AMANDA continues to collect high energy neutrino and muon
data as an independent detector until it is integrated with IceCube. After
introducing both detectors, recent results from AMANDA and a status report on
IceCube are presented.


title: Time lag between prompt optical emission and gamma-rays in GRBs

abstract:
  The prompt optical emission contemporaneous with the $\gamma$-rays from
$\gamma$-ray bursts (GRBs) carries important information on the central engine
and explosion mechanism. We study the time lag between prompt optical emission
and $\gamma$-rays in GRB 990123 and GRB 041219a, which are the only two GRBs
had been detected at optical wavelengths during the ascending burst phase.
Assuming profiles of prompt optical light curves are the same as the prompt
$\gamma$-rays, we simulate optical light curves with different time lags and
compare them with the observed optical flux. Then the best fit time lag and its
error are determined by chi-squared values. We find that time lags between
prompt optical emission and $\gamma$-rays in GRB host galaxy rest-frames are
consistent in the two GRBs, which is $5\sim7$ s for GRB 990123 and $1\sim5$ s
for GRB 041219a. This result is consistent with a common origin of prompt
optical and $\gamma$-ray emissions in the two GRBs. Based on synchrotron
cooling model, we also derive the parameters for the two GRBs.


title: Exotic bulk viscosity and its influence on neutron star r-modes

abstract:
  We investigate the effect of exotic matter in particular, hyperon matter on
neutron star properties such as equation of state (EoS), mass-radius
relationship and bulk viscosity. Here we construct equations of state within
the framework of a relativistic field theoretical model. As hyperons are
produced abundantly in dense matter, hyperon-hyperon interaction becomes
important and is included in this model. Hyperon-hyperon interaction gives rise
to a softer EoS which results in a smaller maximum mass neutron star compared
with the case without the interaction. Next we compute the coefficient of bulk
viscosity and the corresponding damping time scale due to the non-leptonic weak
process including $\Lambda$ hyperons. Further, we investigate the role of the
bulk viscosity on gravitational radiation driven r-mode instability in a
neutron star of given mass and temperature and find that the instability is
effectively suppressed.


title: X-ray Study of Triggered Star Formation and Protostars in IC 1396N

abstract:
  The IC 1396N cometary globule within the large nearby HII region IC 1396 has
been observed with the ACIS detector on board the Chandra X-ray Observatory. We
detect 117 X-ray sources, of which ~50-60 are likely members of the young open
cluster Trumpler~37 dispersed throughout the HII region, and 25 are associated
with young stars formed within the globule. Spitzer/2MASS photometry shows the
X-ray population is very young: 3 older Class III stars, 16 classical T Tauri
stars, 6 protostars including a Class 0/I system. We infer a total T Tauri
population of ~30 stars in the globule, including the undetected population,
with a star formation efficiency of 1-4%. An elongated source spatial
distribution with an age gradient oriented towards the exciting star is
discovered in the X-ray population of IC 1396N, supporting similar findings in
other cometary globules. The geometric and age distribution is consistent with
the RDI model for triggered star formation in CGs by HII region shocks. The
inferred velocity of the shock front propagating into the globule is ~0.6km/s.
The large number of X-ray-luminous protostars in the globule suggests either an
unusually high ratio of Class I/0 vs. Class II/III stars, or a non-standard IMF
favoring higher mass stars by the triggering process. The Chandra source
associated with the luminous Class 0/I protostar IRAS 21391+5802 is one of the
youngest stars ever detected in the X-ray band. We also establish for the first
time that the X-ray absorption in protostars arises from the local infalling
envelopes rather than ambient molecular cloud material.


title:
Lensing signals in the Hubble Ultra-Deep Field using all 2nd order shape
  deformations

abstract:
  The long exposure times of the HST Ultra-Deep Field plus the use of an
empirically derived position-dependent PSF, have enabled us to measure a
cardioid/displacement distortion map coefficient as well as improving upon the
sextupole map coefficient. We confirmed that curved background galaxies are
clumped on the same angular scale as found in the HST Deep Field North. The new
cardioid/displacement map coefficient is strongly correlated to a product of
the sextupole and quadrupole coefficients. One would expect to see such a
correlation from fits to background galaxies with quadrupole and sextupole
moments. Events that depart from this correlation are expected to arise from
map coefficient changes due to lensing, and several galaxy subsets selected
using this criteria are indeed clumped.


title: The tails in the Helix Nebula NGC 7293

abstract:
  We have examined a stream-source model for the production of the cometary
tails observed in the Helix Nebula NGC 7293 in which a transonic or moderately
supersonic stream of ionized gas overruns a source of ionized gas. Hydrodynamic
calculations reveal velocity structures which are in good agreement with the
observational data on tail velocities and are consistent with observations of
the nebular structure. The results also are indicative of a stellar atmosphere
origin for the cometary globules. Tail remnants persist for timescales long
enough for their identification with faint striations visible in the nebula gas
to be plausible.


title: MILES: A Medium resolution INT Library of Empirical Spectra

abstract:
  A new stellar library developed for stellar population synthesis modeling is
presented. The library consist of 985 stars spanning a large range in
atmospheric parameters. The spectra were obtained at the 2.5m INT telescope and
cover the range 3525-7500A at 2.3A (FWHM) spectral resolution. The spectral
resolution, spectral type coverage, flux calibration accuracy and number of
stars represent a substantial improvement over previous libraries used in
population synthesis models.


title: Gas-phase CO in protoplanetary disks: a challenge for turbulent mixing

abstract:
  This is the first paper in a series where we study the influence of turbulent
diffusion and advective transport on the chemical evolution of protoplanetary
disks, using a 2D flared disk model and a 2D mixing gas-grain chemical code
with surface reactions. A first interesting result concerns the abundance of
gas-phase CO in the outer regions of protoplanetary disks. In this Letter we
argue that the gas-phase CO concentration in the disk regions, where the
temperature is lower than $\sim25$ K, can be significantly enhanced due to the
combined effect of vertical and radial mixing. This finding has a potential
implication for the current observational data on the DM~Tau disk chemistry.


title: Coronal loop widths and pressure scale heights

abstract:
  The scale heights of stratification and the widths of steady solar coronal
loops exhibit properties unexplained by standard theory: observed scale heights
are often much greater than static theory predicts, while the nearly-constant
widths of loop emission signatures defy theoretical expectations for large flux
tubes in stratified media. In this work we relate the cross-sectional profile
of a coronal flux tube to its density scale height in steady-state plasma flow
regimes. Steady flows may shorten or lengthen the scale height according to how
the tube cross-sectional area varies with arclength. In a near-potential corona
the flux tubes are expected to be sufficiently expansive in many active regions
for scale heights to be increased by steady flows. On the other hand, cases
where scale lengths are actually increased to observed sizes form a small part
of the solution space, close to regimes where density profiles reverse.
Therefore, although steady flows are the only steady process known to be
capable of extending scale heights significantly, they are not expected to be
not responsible for the majority of extended active region scale heights.


title:
New nonadiabatic pulsation computations on full PG1159 evolutionary
  models: the theoretical GW Vir instability strip revisited

abstract:
  We reexamine the theoretical instability domain of pulsating PG1159 stars (GW
Vir variables). We performed an extensive g-mode stability analysis on PG1159
evolutionary models with stellar masses ranging from 0.530 to 0.741 Mo for
which the complete evolutionary stages of their progenitors from the ZAMS,
through the thermally pulsing AGB and born-again phases to the domain of the
PG1159 stars have been considered. We found that pulsations in PG1159 stars are
excited by the kappa-mechanism due to partial ionization of carbon and oxygen,
and that no composition gradients are needed between the surface layers and the
driving region, much in agreement with previous studies. We show, for the first
time, the existence of a red edge of the instability strip at high
luminosities. We found that all of the GW Vir stars lay within our theoretical
instability strip. Our results suggest a qualitative good agreement between the
observed and the predicted ranges of unstable periods of individual stars.
Finally, we found that generally the seismic masses (derived from the period
spacing) of GW Vir stars are somewhat different from the masses suggested by
evolutionary tracks coupled with spectroscopy. Improvements in the evolution
during the thermally pulsing AGB phase and/or during the core helium burning
stage and early AGB could help to alleviate the persisting discrepancies.


title:
Population III star formation in a Lambda CDM universe, I: The effect of
  formation redshift and environment on protostellar accretion rate

abstract:
  (abridged) We perform 12 extremely high resolution adaptive mesh refinement
cosmological hydrodynamic simulations of Population III star formation in a
Lambda CDM universe, varying the box size and large-scale structure, to
understand systematic effects in the formation of primordial protostellar
cores. We find results that are qualitatively similar to those observed
previously. We observe that the threshold halo mass for formation of a
Population III protostar does not evolve significantly with time in the
redshift range studied (33 > z > 19) but exhibits substantial scatter due to
different halo assembly histories: Halos which assembled more slowly develop
cooling cores at lower mass than those that assemble more rapidly, in agreement
with Yoshida et al. (2003). We do, however, observe significant evolution in
the accretion rates of Population III protostars with redshift, with objects
that form later having higher maximum accretion rates, with a variation of two
orders of magnitude (10^-4 - 10^-2 Msolar/year). This can be explained by
considering the evolving virial properties of the halos with redshift and the
physics of molecular hydrogen formation at low densities. Our result implies
that the mass distribution of Population III stars inferred from their
accretion rates may be broader than previously thought, and may evolve with
redshift. Finally, we observe that our collapsing protostellar cloud cores do
not fragment, consistent with previous results, which suggests that Population
III stars which form in halos of mass 10^5 - 10^6 Msun always form in
isolation.


title:
Theory for the Secondary Eclipse Fluxes, Spectra, Atmospheres, and Light
  Curves of Transiting Extrasolar Giant Planets

abstract:
  We have created a general methodology for calculating the
wavelength-dependent light curves of close-in extrasolar giant planets (EGPs)
as they traverse their orbits. Focussing on the transiting EGPs HD189733b,
TrES-1, and HD209458b, we calculate planet/star flux ratios during secondary
eclipse and compare them with the Spitzer data points obtained so far in the
mid-infrared. We introduce a simple parametrization for the redistribution of
heat to the planet's nightside, derive constraints on this parameter (P_n), and
provide a general set of predictions for planet/star contrast ratios as a
function of wavelength, model, and phase. Moreover, we calculate average
dayside and nightside atmospheric temperature/pressure profiles for each
transiting planet/P_n pair with which existing and anticipated Spitzer data can
be used to probe the atmospheric thermal structure of severely irradiated EGPs.
We find that the baseline models do a good job of fitting the current secondary
eclipse dataset, but that the Spitzer error bars are not yet small enough to
discriminate cleanly between all the various possibilities.


title:
Chemical Abundances in the Secondary Star of the Black Hole Binary V4641
  Sagittarii (SAX J1819.3-2525)

abstract:
  We report on detailed spectroscopic studies performed for the secondary star
in the black hole binary (micro-quasar) V4641 Sgr in order to examine its
surface chemical composition and to see if its surface shows any signature of
pollution by ejecta from a supernova explosion. High-resolution spectra of
V4641 Sgr observed in the quiescent state in the blue-visual region are
compared with those of the two bright well-studied B9 stars (14 Cyg and $\nu$
Cap) observed with the same instrument. The effective temperature of V4641 Sgr
(10500 $\pm$ 200 K) is estimated from the strengths of He~{\sc i} lines, while
its rotational velocity, $\it v$ sin $\it i$ (95 $\pm$ 10 km s${}^{-1}$), is
estimated from the profile of the Mg~{\sc ii} line at 4481 \AA. We obtain
abundances of 10 elements and find definite over-abundances of N (by 0.8 dex or
more) and Na (by 0.8 dex) in V4641 Sgr. From line-by-line comparisons of eight
other elements (C, O, Mg, Al, Si, Ti, Cr, and Fe) between V4641 Sgr and the two
reference stars, we conclude that there is no apparent difference in the
abundances of these elements between V4641 Sgr and the two normal late B-type
stars, which have been reported to have solar abundances. An evolutionary model
of a massive close binary system has been constructed to explain the abundances
observed in V4641 Sgr. The model suggests that the progenitor of the black hole
forming supernova was as massive as ~ 35 Msun on the main-sequence and, after
becoming a ~ 10 Msun He star, underwent "dark" explosion which ejected only N
and Na-rich outer layer of the He star without radioactive $^{56}$Ni.


title:
On Dissipation inside Turbulent Convection Zones from 3D Simulations of
  Solar Convection

abstract:
  The development of 2D and 3D simulations of solar convection has lead to a
picture of convection quite unlike the usually assumed Kolmogorov spectrum
turbulent flow. We investigate the impact of this changed structure on the
dissipation properties of the convection zone, parametrized by an effective
viscosity coefficient. We use an expansion treatment developed by Goodman & Oh
1997, applied to a numerical model of solar convection (Robinson et al. 2003)
to calculate an effective viscosity as a function of frequency and compare this
to currently existing prescriptions based on the assumption of Kolmogorov
turbulence (Zahn 1966, Goldreich & Keeley 1977). The results match quite
closely a linear scaling with period, even though this same formalism applied
to a Kolmogorov spectrum of eddies gives a scaling with power-law index of 5/3.


title:
Sulphur abundances in disk stars as determined from the forbidden 10821
  A [SI] line

abstract:
  Aims: In this paper we aim to study the chemical evolution of sulphur in the
galactic disk, using a new optimal abundance indicator: the [SI] line at 10821
A. Similar to the optimal oxygen indicators, the [OI] lines, the [SI] line has
the virtues of being less sensitive to the assumed temperatures of the stars
investigated and of likely being less prone to non-LTE effects than other
tracers. Methods: High-resolution, near-infrared spectra of the [SI] line are
recorded using the Phoenix spectrometer on the Gemini South telescope. The
analysis is based on 1D, LTE model atmospheres using a homogeneous set of
stellar parameters. Results: The 10821 A [SI] line is suitable for an abundance
analysis of disk stars, and the sulphur abundances derived from it are
consistent with abundances derived from other tracers. We corroborate that, for
disk stars, the trend of sulphur-to-iron ratios with metallicity is similar to
that found for other alpha elements, supporting the idea of a common
nucleosynthetic origin.


title:
Shock-Wave Heating Model for Chondrule Formation: Prevention of Isotopic
  Fractionation

abstract:
  Chondrules are considered to have much information on dust particles and
processes in the solar nebula. It is naturally expected that protoplanetary
disks observed in present star forming regions have similar dust particles and
processes, so study of chondrule formation may provide us great information on
the formation of the planetary systems.
  Evaporation during chondrule melting may have resulted in depletion of
volatile elements in chondrules. However, no evidence for a large degree of
heavy-isotope enrichment has been reported in chondrules. In order to meet this
observed constraint, the rapid heating rate at temperatures below the silicate
solidus is required to suppress the isotopic fractionation.
  We have developed a new shock-wave heating model taking into account the
radiative transfer of the dust thermal continuum emission and the line emission
of gas molecules and calculated the thermal history of chondrules. We have
found that optically-thin shock waves for the thermal continuum emission from
dust particles can meet the rapid heating constraint, because the dust thermal
emission does not keep the dust particles high temperature for a long time in
the pre-shock region and dust particles are abruptly heated by the gas drag
heating in the post-shock region. We have also derived the upper limit of
optical depth of the pre-shock region using the radiative diffusion
approximation, above which the rapid heating constraint is not satisfied. It is
about 1 - 10.


title: Star formation bursts in isolated spiral galaxies

abstract:
  We study the response of the gaseous component of a galactic disc to the time
dependent potential generated by N-body simulations of a spiral galaxy. The
results show significant variation of the spiral structure of the gas which
might be expected to result in significant fluctuations in the Star Formation
Rate (SFR). Pronounced local variations of the SFR are anticipated in all
cases. Bursty histories for the global SFR, however, require that the mean
surface density is much less (around an order of magnitude less) than the
putative threshold for star formation. We thus suggest that bursty star
formation histories, normally attributed to mergers and/or tidal interactions,
may be a normal pattern for gas poor isolated spiral galaxies.


title: ESO Imaging Survey: Infrared Deep Public Survey

abstract:
  This paper presents new J and Ks data obtained from observations conducted at
the ESO 3.5m New Technology Telescope using the SOFI camera. These data were
taken as part of the ESO Imaging Survey Deep Public Survey (DPS) and
significantly extend the earlier optical/infrared EIS-DEEP survey presented in
a previous paper. The DPS-IR survey comprises two observing strategies: shallow
Ks observations providing nearly full coverage of pointings with complementary
multi-band optical data and deeper J and Ks observations of the central parts
of these fields. The DPS-IR survey provides a coverage of roughly 2.1 square
degrees in Ks with 0.63 square degrees to fainter magnitudes and also covered
in J, over three independent regions of the sky. The goal of the present paper
is to describe the observations, the data reduction procedures, and to present
the final survey products. The astrometric solution with an estimated accuracy
of <0.15" is based on the USNO catalog. The final stacked images presented here
number 89 and 272, in J and Ks, respectively, the latter reflecting the larger
surveyed area. The J and Ks images were taken with a median seeing of 0.77" and
0.8". The images reach a median 5sigma limiting magnitude of J_AB~23.06 in an
aperture of 2", while the corresponding limiting magnitude in Ks_AB is ~21.41
and ~22.16 mag for the shallow and deep strategies. Overall, the observed
limiting magnitudes are consistent with those originally proposed. The quality
of the data has been assessed by comparing the measured magnitude of sources at
the bright end directly with those reported by the 2MASS survey and at the
faint end by comparing the counts of galaxies and stars with those of other
surveys to comparable depth and to model predictions. The final science-grade
catalogs and images are available at CDS.


title: Searching for AGN-driven Shocks in Galaxy Clusters

abstract:
  Shocks and blastwaves are expected to be driven driven into the intracluster
medium filling galaxy groups and clusters by powerful outbursts of active
galactic nuclei or quasars in the member galaxies; the first footprints of
shock fronts have been tentatively traced out with X-ray imaging. We show how
overpressures in the blasts behind the shock can prove the case and also
provide specific marks of the nuclear activity: its strength, its current
stage, and the nature of its prevailing output. We propose to detect these
marks with the aimed pressure probe constituted by the resolved
Sunyaev-Zel'dovich effect. We compute and discuss the outcomes to be expected
in nearby and distant sources at different stages of their activity.


title:
GaBoDS: The Garching-Bonn Deep Survey -- IX. A sample of 158
  shear-selected mass concentration candidates

abstract:
  The aim of the present work is the construction of a mass-selected galaxy
cluster sample based on weak gravitational lensing methods. This sample will be
subject to spectroscopic follow-up observations.
  We apply the mass aperture statistics and a derivative of it to 19 square
degrees of high quality, single colour wide field imaging data obtained with
the WFI@MPG/ESO 2.2m telescope. For the statistics a family of filter functions
is used that approximates the expected tangential radial shear profile and thus
allows for the efficient detection of mass concentrations.
  We identify 158 possible mass concentrations. This is the first time that
such a large and blindly selected sample is published. 72 of the detections are
associated with concentrations of bright galaxies. For about 22 of those we
found spectra in the literature, indicating or proving that the galaxies seen
are indeed spatially concentrated. 15 of those were previously known to be
clusters or have meanwhile been secured as such. We currently follow-up a
larger number of them spectroscopically to obtain deeper insight into their
physical properties. The remaining 55% of the possible mass concentrations
found are not associated with any optical light, or could not be classified
unambiguously. We show that those "dark" detections are to a significant degree
due to noise, and appear preferentially in shallow data.


title:
Disentangling the synchrotron and Inverse Compton variability in the
  X-ray emission of the intermediate BL Lac object S5 0716+71

abstract:
  The possibility to detect simultaneously in the X-ray band the synchrotron
and Inverse Compton (IC)emission of intermediate BL Lac objects offers the
unique opportunity to study contemporaneously the low- and high-energy tails of
the electron distribution in the jets of these sources. We attempted to
disentangle the X-ray spectral variability properties of both the low- and
high-energy ends of the synchrotron and Inverse Compton emission of the
intermediate BL Lac object S5 0716+71. We carried out spectral, temporal and
cross-correlation analyses of the data from a long XMM-Newton pointing of S5
0716+71 and we compared our findings with previous results from past X-ray
observations. Strong variability was detected during the XMM exposure.Both the
synchrotron and Inverse Compton components were found to vary on time scales of
hours, implying a size of the emitting region of $R\la 0.7\delta /(1+z)$
light-hours. The synchrotron emission was discovered to become dominant during
episodes of flaring activity, following a harder-when-brighter trend. Tight
correlations were observed between variations in different energy bands. Upper
limits on time lags between the soft and hard X-ray light curves are of the
order of a few hundred seconds.


title: Tidal Mass Loss from Collisionless Systems

abstract:
  We examine the problem tidally-induced mass loss from collisionless systems
such as dark matter haloes. We develop a model for tidal mass loss, based upon
the phase space distribution of particles, which accounts for how both tidal
and Coriolis torques perturb the angular momentum of each particle in the
system. This allows us to study how both the density profile and velocity
anisotropy affect the degree of mass loss--we present basic results from such a
study. Our model predicts that mass loss is a continuous process even in a
static tidal field, a consequence of the fact that mass loss weakens the
potential of the system making it easier for further mass loss to occur. We
compare the predictions of our model with N-body simulations of idealized
systems in order to check its validity. We find reasonable agreement with the
N-body simulations except for in the case of very strong tidal fields, where
our results suggest that a higher-order perturbation analysis may be required.
The continuous tidally-induced mass loss predicted by our model can lead to
substantial reduction in satellite mass in cases where the traditional
treatment predicts no mass loss. As such, our results may have important
consequences for the orbits and survival of low mass satellites in dark matter
haloes.