title: Particle Acceleration at High-$\gamma$ Shock Waves

abstract:
  First-order Fermi acceleration processes at ultrarelativistic shocks are
studied with Monte Carlo simulations. The accelerated particle spectra are
obtained by integrating the exact particle trajectories in a turbulent magnetic
field near the shock, with a few ``realistic'' features of the field structure
included. We show that the main acceleration process at oblique shocks is the
particle compression at the shock. Formation of energetic spectral tails is
possible in a limited energy range for highly perturbed magnetic fields.
Cut-offs in the spectra occur at low energies in the resonance range
considered. We relate this feature to the structure of the magnetic field
downstream of the shock, where field compression produces effectively 2D
turbulence in which cross-field diffusion is very small. Because of the field
compression downstream, the acceleration process is inefficient also in
parallel high-$\gamma$ shocks for larger turbulence amplitudes, and features
observed in oblique shocks are recovered. For small-amplitude perturbations,
particle spectra are formed in a wide energy range and modifications of the
acceleration process due to the existence of long-wave perturbations are
observed. The critical turbulence amplitude for efficient acceleration at
parallel shocks decreases with shock Lorentz factor. We also study the
influence of strong short-wave perturbations downstream of the shock on the
particle acceleration processes. The spectral indices obtained do not converge
to the ``universal'' value . Our results indicate inefficiency of the
first-order Fermi process to generate high-energy cosmic rays at
ultrarelativistic shocks with the considered perturbed magnetic field
structures.


title: Radiative Processes In Extragalactic Large-Scale Jets

abstract:
  About one thousand extragalactic large-scale jets are known, and a few tens
of them are confirmed sources of infrared, optical, or X-ray photons.
Multiwavelength emission comming directly from these outflows is always
non-thermal in origin. This fact constitutes a primary difficulty in extracting
unknown parameters of large-scale jets, since the non-thermal featureless
continua do not allow to infer undoubtfully (or even at all) bulk velocities
and composition of the radiating plasma. In addition, arcsecond spatial
resolution, limited sensitivity and narrow energy bands of the best
high-frequency telescopes like Spitzer, Hubble and Chandra, preclude precise
constraints on the spectral and morphological properties of the discussed
objects. Nevertheless, new multiwavelength observations have substantially
enriched our knowledge on extragalactic large-scale jets, in many aspects,
however, by means of challenging previous predictions and expectations. In this
short contribution I will concentrate on the following issue: what can be
learned by analyzing broad-band emission of the discussed objects about
particle acceleration processes acting thereby and about jet internal
parameters.


title: The Araucaria Project

abstract:
  {Results from a long-term observational project called the Araucaria Project
are presented. Based on Wide Field optical monitoring of 8 nearby galaxies,
covering a large range of metallicities, more than 500 Cepheids and a few
hundred Blue Supergiant candidates were identified. From the analysis of
Cepheid P-L relations of outstanding quality derived from our data we conclude
that the slope of these relations in the I band and Wesenheit index are not
dependent on metallicity. Comparing the I-band magnitudes of Cepheids of a
period of ten days, as computed from our P-L relations, to the I-band
magnitudes of the tip of the RGB, which is widely believed to be independent of
population effects, we cannot see any obvious dependence of the zero point of
the I-band P-L relation on metallicity. A preliminary analysis of IR follow-up
observations of sub-samples of the identified Cepheids in various galaxies of
the project show that the distances obtained from these data are systematically
shorter by about of 0.1 mag than those derived from the optical photometry. It
is likely that this effect can be attributed to the internal reddening in the
program galaxies.


title: Swift XRT Observations of the Afterglow of GRB 050319

abstract:
  Swift discovered the high redshift GRB 050319 with the Burst Alert Telescope
and began observing with its narrow field instruments only 225 s after the
burst onset. The afterglow X-ray emission was monitored by the XRT up to 28
days after the burst. The light curve shows a decay with three different
phases, each characterized by a distinct slope: an initial steep decay with a
power law index of ~ 5.5, a second phase characterized by a flat decay slope of
\~ 0.54, and a third phase with a decay slope of ~ 1.14. During the first phase
the spectral energy distribution is softer than in the following two phases and
the photon index is consistent with the GRB prompt spectrum. The extrapolation
of the BAT light curve to the XRT band suggests that the initial fast decaying
phase of the XRT afterglow might be the low energy tail of the prompt emission.
The second break in the afterglow light curve occurs about 27000 s after the
burst. The spectral energy distribution before and after the second break does
not change and it can be tentatively interpreted as a jet break or the end of a
delayed or continuous energy injection phase.


title:
Near-Infrared search for C IV absorption counterparts along the
  line-of-sights to pair quasars

abstract:
  We carried out a Subaru and UKIRT near infrared imaging survey for H-alpha
emitting galaxies around two pair quasar systems (Q0301-005/Q0302-003 and
Q2343+125/Q2344+125), and a triple quasar system (KP76/KP77/KP78). Narrow band
near infrared filters covering the H-alpha emission expected for galaxies at
the confirmed C IV absorption redshift toward the quasar systems were used for
this survey. These quasar pairs or triplet are separated at most by 17 arcmins
(~5 h^-1 Mpc in proper distance) from each other on the sky, and have common C
IV absorption lines at almost identical redshifts at z=2.24-2.43, which
suggests there could be a Mpc-scale absorbing systems such as a cluster, or a
group, of galaxies that cover all the line-of-sights to the pair/triple
quasars. Using narrow-band deep images, we detected five candidates for H-alpha
emitting galaxies around two of the six fields, Q2343+125 and Q2344+125, whose
apparent star formation rates are, extremely high, 20-466 M_solar/year.
However, all or most of them are not likely to be galaxies at the absorption
redshift but galaxies at lower redshift, because of their extreme brightness.
In the fields of the other quasars, we detected no star-forming galaxies, nor
did we find any number excess of galaxy counts around them. This no-detection
results could be because the luminosities and star formation rates of galaxies
are lower than the detection limits of our observations (K' > 21 and SFR <
1.8-240 h^-2 M_solar/year). They could be located outside of the observed
fields by chance. Otherwise, most C IV absorption lines could be ascribed not
to cluster of galaxies, but to isolated star forming pockets far from bright
galaxies and could be analogous objects to weak Mg II absorbers.


title:
Evidence for a Universal Slope of the Period-Luminosity Relation from
  Direct Distances to Cepheids in the LMC

abstract:
  We have applied the infrared surface brightness (ISB) technique to derive
distances to 13 Cepheid variables in the LMC which have periods from 3-42 days.
The corresponding absolute magnitudes define PL relations in VIWJK bands which
agree exceedingly well with the corresponding Milky Way relations obtained from
the same technique, and are in significant disagreement with the observed LMC
Cepheid PL relations, by OGLE-II and Persson et al., in these bands. Our data
uncover a systematic error in the p-factor law which transforms Cepheid radial
velocities into pulsational velocities. We correct the p-factor law by
requiring that all LMC Cepheids share the same distance. Re-calculating all
Milky Way and LMC Cepheid distances with the revised p-factor law, we find that
the PL relations from the ISB technique both in LMC and in the Milky Way agree
with the OGLE-II and Persson et al. LMC PL relations, supporting the conclusion
of no metallicity effect on the slope of the Cepheid PL relation in
optical/near infrared bands.


title:
A Compton reflection dominated spectrum in a peculiar accreting neutron
  star

abstract:
  We report on a puzzling event occurred during a long BeppoSAX observation of
the slow-rotating binary pulsar GX 1+4. During this event, lasting about 1 day,
the source X-ray flux was over a factor 10 lower than normal. The low-energy
pulsations disappeared while at higher energies they were shifted in phase. The
spectrum taken outside this low-intensity event was well fitted by an absorbed
cut-off power law, and exhibited a broad iron line at ~6.5 keV probably due to
the blending of the neutral (6.4 keV) and ionised (6.7 keV) K_alpha iron lines.
The spectrum during the event was Compton reflection dominated and it showed
two narrow iron lines at ~6.4 keV and ~7.0 keV, the latter never revealed
before in this source. We also present a possible model for this event in which
a variation of the accretion rate thickens a torus-like accretion disc which
hides for a while the direct neutron star emission from our line of sight. In
this scenario the Compton reflected emission observed during the event is well
explained in terms of emission reflected by the side of the torus facing our
line of sight.


title: A differential rotation driven dynamo in a stably stratified star

abstract:
  We present numerical simulations of a self-sustaining magnetic field in a
differentially rotating non-convective stellar interior. A weak initial field
is wound up by the differential rotation; the resulting azimuthal field becomes
unstable and produces a new meridional field component, which is then wound up
anew, thus completing the `dynamo loop'. This effect is observed both with and
without a stable stratification. A self-sustained field is actually obtained
more easily in the presence of a stable stratification. The results confirm the
analytical expectations of the role of Tayler instability.


title:
Giant Molecular Clouds are More Concentrated to Spiral Arms than Smaller
  Clouds

abstract:
  From our catalog of Milky Way molecular clouds, created using a temperature
thresholding algorithm on the Bell Laboratories 13CO Survey, we have extracted
two subsets:(1) Giant Molecular Clouds (GMCs), clouds that are definitely
larger than 10^5 solar masses, even if they are at their `near distance', and
(2) clouds that are definitely smaller than 10^5 solar masses, even if they are
at their `far distance'. The positions and velocities of these clouds are
compared to the loci of spiral arms in (l, v) space. The velocity separation of
each cloud from the nearest spiral arm is introduced as a `concentration
statistic'. Almost all of the GMCs are found near spiral arms. The density of
smaller clouds is enhanced near spiral arms, but some clouds (~10%) are
unassociated with any spiral arm. The median velocity separation between a GMC
and the nearest spiral arm is 3.4+-0.6 km/s, whereas the median separation
between smaller clouds and the nearest spiral arm is 5.5+-0.2 km/s.


title:
ESO-VLT and Spitzer spectroscopy of IRAS05328-6827: a massive young
  stellar object in the Large Magellanic Cloud

abstract:
  We present the first thermal-infrared spectra of an extra-galactic Young
Stellar Object (YSO), IRAS05328-6827 in the HII region LHA 120-N148 in the
Large Magellanic Cloud. The observed and modelled spectral energy distribution
reveals a massive YSO, M=20 Msun, which is heavily-embedded and probably still
accreting. The reduced dust content as a consequence of the lower metallicity
of the LMC allows a unique view into this object, and together with a high C/O
ratio may be responsible for the observed low abundance of water ice and
relatively high abundances of methanol and CO2 ices.


title:
Supernova Remnants in the Magellanic Clouds. VI. The DEML316 Supernova
  Remnants

abstract:
  The DEML316 system contains two shells, both with the characteristic
signatures of supernova remnants (SNRs). We analyze Chandra and XMM-Newton data
for DEML316, investigating its spatial and spectral X-ray features. Our Chandra
observations resolve the structure of the northeastern SNR (Shell A) as a
bright inner ring and a set of "arcs" surrounded by fainter diffuse emission.
The spectrum is well fit by a thermal plasma model with temperature ~1.4 keV;
we do not find significant spectral differences for different regions of this
SNR. The southwestern SNR (Shell B) exhibits an irregular X-ray outline, with a
brighter interior ring of emission including a bright knot of emission. Overall
the emission of the SNR is well described by a thermal plasma of temperature
~0.6 keV. The Bright Knot, however, is spectrally distinct from the rest of the
SNR, requiring the addition of a high-energy spectral component consistent with
a power-law spectrum of photon index 1.6--1.8.
  We confirm the findings of Nishiuchi et al. (2001) that the spectra of these
shells are notably different, with Shell A requiring a high iron abundance for
a good spectral fit, implying a Type Ia origin. We further explicitly compare
abundance ratios to model predictions for Type Ia and Type II supernovae. The
low ratios for Shell A (O/Fe of 1.5 and Ne/Fe of 0.2) and the high ratios for
Shell B (O/Fe of 30--130 and Ne/Fe of 8--16) are consistent with Type Ia and
Type II origins, respectively. The difference between the SNR progenitor types
casts some doubt on the suggestion that these SNRs are interacting with one
another.


title: Cosmological Implications of the Very High Redshift GRB 050904

abstract:
  We report near simultaneous multi-color (RIYJHK) observations made with the
MAGNUM 2m telescope of the gamma ray burst GRB 050904 detected by the SWIFT
satellite. The spectral energy distribution shows a very large break between
the I and J bands. Using intergalactic transmissions measured from high
redshift quasars we show that the observations place a 95% confidence lower
limit of z=6.18 on the object, consistent with a later measured spectroscopic
redshift of 6.29 obtained by Kawai et al. (2005) with the Subaru telescope. We
show that the break strength in the R and I bands is consistent with that
measured in the quasars. Finally we consider the implications for the star
formation history at high redshift.


title: Thermonuclear Kinetics in Astrophysics

abstract:
  Over the billions of years since the Big Bang, the lives, deaths and
afterlives of stars have enriched the Universe in the heavy elements that make
up so much of ourselves and our world. This review summarizes the methods used
to evolve these nuclear abundances within astrophysical simulations. These
methods fall into 2 categories; evolution via rate equations and via
equilibria. Because the rate equations in nucleosynthetic applications involve
a wide range of timescales, implicit methods have proven mandatory, leading to
the need to solve matrix equations. Efforts to improve the performance of such
rate equation methods are focused on efficient solution of these matrix
equations, in particular by making best use of the sparseness of these
matrices, and finding methods that require less frequent matrix solutions.
Recent work to produce hybrid schemes which use local equilibria to reduce the
computational cost of the rate equations is also discussed. Such schemes offer
significant improvements in the speed of reaction networks and are accurate
under circumstances where calculations which assume complete equilibrium fail.


title:
NEBU_3D: A fast pseudo-3D photoionization code for aspherical planetary
  nebulae and HII regions

abstract:
  We describe a pseudo-3D photoionization code, NEBU_3D and its associated
visualization tool, VIS_NEB3D, which are able to easily and rapidly treat a
wide variety of nebular geometries, by combining models obtained with a 1D
photoionization code. We also present a tool, VELNEB_3D, which can be applied
to the results of 1D or 3D photoionization codes to generate emission line
profiles, position-velocity maps and 3D maps in any emission line by assuming
an arbitrary velocity field. As examples of the capabilities of these new
tools, we consider three very different theoretical cases. The first one is a
blister HII region, for which we have also constructed a spherical model (the
spherical impostor) which has exactly the same Hbeta surface brightness
distribution as the blister model and the same ionizing star. The second
example shows how complex line profiles can be obtained even with a simple
expansion law if the nebula is bipolar and the slit slightly off-center. The
third example shows different ways to produce line profiles that could be
attributed to a turbulent velocity field while there is no turbulence in the
model.


title: Extragalactic Thick Disks: Implications for Early Galaxy Evolution

abstract:
  I briefly review the growing evidence that thick stellar disks surround most
edge-on disk galaxies. Recent studies show that these extragalactic thick disks
have old ages, low metallicities, long scale lengths, and moderately flattened
axial ratios, much like the thick disk of the Milky Way. However, the
properties of thick disks change systematically with the mass of the galaxy.
The thick disks of low mass galaxies are more prominent and somewhat more
metal-poor than those surrounding massive disk galaxies. Given the strong
evidence that thick disks are fossils from an early epoch of merging, these
trends place tight constraints on the early assembly of disk galaxies. The data
suggest that the vast majority of the accretion onto the early disk was
gaseous, but that the majority of thick disk stars were directly accreted.


title:
Planetesimal growth in turbulent discs before the onset of gravitational
  instability

abstract:
  It is difficult to imagine a planet formation model that does not at some
stage include a gravitationally unstable disc. Initially unstable gas-dust
discs may form planets directly, but the high surface density required has
motivated the alternative that gravitational instability occurs in a dust
sub-layer only after grains have grown large enough by electrostatic sticking.
Although such growth up to the instability stage is efficient for laminar
discs, concern has mounted as to whether realistic disc turbulence
catastrophically increases the settling time, thereby requiring additional
processes to facilitate planet formation on the needed time scales. To evaluate
this concern, we develop a model for grain growth that accounts for the
influence of turbulence on the collisional velocity of grains and on the scale
height of the dust layer. The relative effect on these quantities depends on
the grain size. The model produces a disc-radius dependent time scale to reach
a gravitationally unstable phase of planet formation. For a range of dust
sticking and disc parameters, we find that for viscosity parameters $\alpha \le
10^{-3}$, this time scale is short enough over a significant range in radii $R$
that turbulence does not catastrophically slow the early phases of planet
formation, even in the absence of agglomeration enhancement agents like
vortices.


title:
Seyfert Galaxies and the Hard X-ray Background: Artificial Chandra
  Observations of z = 0.3 Active Galaxies

abstract:
  Deep X-ray surveys have resolved much of the X-ray background radiation below
2 keV into discrete sources, but the background above 8 keV remains largely
unresolved. The obscured (type 2) Active Galactic Nuclei (AGNs) that are
expected to dominate the hard X-ray background have not yet been detected in
sufficient numbers to account for the observed background flux. However, deep
X-ray surveys have revealed large numbers of faint quiescent and starburst
galaxies at moderate redshifts. In hopes of recovering the missing AGN
population, it has been suggested that the defining optical spectral features
of low-luminosity Seyfert nuclei at large distances may be overwhelmed by their
host galaxies, causing them to appear optically quiescent in deep surveys. We
test this possibility by artificially redshifting a sample of 23 nearby,
well-studied active galaxies to z = 0.3, testing them for X-ray AGN signatures
and comparing them to the objects detected in deep X-ray surveys. We find that
these redshifted galaxies have properties consistent with the deep field
``normal'' and ``optically bright, X-ray faint'' (OBXF) galaxy populations,
supporting the hypothesis that the numbers of AGNs in deep X-ray surveys are
being underestimated, and suggesting that OBXFs should not be ruled out as
candidate AGN hosts that could contribute to the hard X-ray background source
population.


title: Strange Star Equation of State With a Modified Richardson Potential

abstract:
  Richardson potential is an phenomenological interquark interaction taking
care of two aspects of QCD, namely the asymptotic freedom and the confinement.
The original potential has a scale parameter having value around 400 MeV and is
well tested in hadronic property calculations. This potential was then used in
strange star calculation. Strange stars are very compact stars composed of
strange quark matter i.e. a very high density strange quark phase consisting of
deconfined u, d and s quarks. Here the value of the scale parameter was taken
as 100 MeV. The argument was that for a deconfined quark system like a strange
star, the scale parameter may have a value quite different from that used in
hadronic sector. To remove this discrepancy we introduced two scale parameters
in the potential, one for the asymptotic freedom part and the other for the
confining part. With suitable values of the parameters, this modified potential
has been successfully used in both baryonic property and strange star
calculations. The Equation of States obtained with the modified potential are
also used to obtain mass-radius relations for the strange stars.


title:
The Millennium Galaxy Catalogue: The nearby supermassive black hole mass
  function

abstract:
  We highlight the correlation between a galaxy's supermassive black hole mass
and the Sersic-index of the host spheroid or bulge component. From our
bulge-disk decompositions of 10 095 galaxies, drawn from the Millennium Galaxy
Catalogue, we construct the local (z < 0.18) mass function of supermassive
black holes. We compare our results to those of McLure & Dunlop (2004) and
conclude that the mass density of supermassive black holes may be marginally
higher than previously supposed. This increase is predominantly due to the
inclusion of low mass and later-type bulges. More details will be presented in
a forthcoming paper.


title: Widely separated binary systems of very low mass stars

abstract:
  In this paper we review some recent detections of wide binary brown dwarf
systems and discuss them in the context of the multiplicity properties of very
low-mass stars and brown dwarfs.


title:
GAW, Gamma Air Watch - A Large Field of View Imaging Atmospheric
  Cherenkov

abstract:
  GAW, acronym for Gamma Air Watch, is a path-finder experiment to test the
feasibility of a new generation of imaging atmospheric Cherenkov telescopes
that join high flux sensitivity with large field of view capability. GAW is
conceived as an array of three identical imaging telescopes disposed at the
vertexes of an equilateral triangle, about 80 m side. Two main features
characterize GAW with respect to all the existing and presently planned
ground-based Cherenkov telescopes. The first difference concerns the optics
system: GAW uses a Fresnel refractive lens (2.13 m diameter) as light collector
instead of classical reflective mirror. The second main difference is the
detection working mode used: the detector at the focal surface operates in
single photoelectron counting mode instead of the usual charge integration one.
The GAW array is planned to be located at the Calar Alto Observatory site,
Spain, 2150 m a.s.l. During its first phase, only 6x6 degrees of the focal
plane detector will be implemented; moving it along the field of view, the
sensitivity of the telescopes will be tested observing the Crab Nebula with
on-axis and off-axis pointing up to 20 deg and with energy threshold of 300 GeV
and energy peak of 700 GeV. As path-finder, GAW will also monitor the Very High
Energy activity of some flaring Blazars as well as will follow-up GLAST
detections at high energies. In a second phase, the focal plane will be
enlarged to cover a field of view of 24 deg (full); pointing along different
North-South directions, GAW would reach a survey of 360x60 degrees region of
the sky. GAW is a collaboration effort of Research Institutes in Italy,
Portugal and Spain.


title: Evolution of local Ultraluminous mergers from NIR spectroscopy

abstract:
  We present results from our VLT Large Program to study the dynamical
evolution of Ultraluminous Infrared Galaxies (ULIRGs). We have so far obtained
near-infrared high-resolution ISAAC spectra of 53 local ULIRGs at several
merger timescales and 12 Palomar-Green QSOs (more than half of which are
IR-bright sources). We have extracted the stellar velocity dispersion and
rotational velocity along our slits to derive the kinematics of the merging
galaxies. These quantities enable us to answer the following questions about
the evolution of ULIRGs: 1) What are the progenitor mass ratios?, 2) How do the
stellar kinematics evolve?, and, 3) Is there a connection between ULIRGs and
QSOs? We find that the Ultraluminous phase is mainly triggered by mergers of
approximately equal mass galaxies, however, less violent minor mergers (of
progenitor mass ratio ~3:1) also exist in our sample. Dynamical heating of the
merging hosts is observed as the stellar systematic rotation decreases with
time in favour of the increase of random motions. The merger remnants, being
dispersion-dominated systems with non-negligible rotation, resemble elliptical
galaxies. Placing ULIRGs on the fundamental plane of early-type galaxies shows
that they resemble intermediate-mass ellipticals. After the nuclear
coalescence, the black hole masses of ULIRGs, calculated from their relation to
the host dispersions, are of the order 10^7-10^8 M_sun. To investigate whether
ULIRGs go through a QSO phase during their evolution, we perform a similar
(preliminary) analysis of the IR-bright-QSO kinematics. We find that the
average dispersion of the IR-bright QSOs is similar to that of the ULIRG
remnants, indicating that evolutionary links between the two populations may
exist.


title: Application of the global modal approach to spiral galaxies

abstract:
  We have tested the applicability of the global modal approach in the density
wave theory of spiral structure for a sample of six spiral galaxies: NGC 488,
NGC 628, NGC 1566, NGC 2985, NGC 3938 and NGC 6503. The galaxies demonstrate a
variety of spiral patterns from the regular open and tightly wound spiral
patterns to a multi-armed spiral structure. Using the observed radial
distributions of the stellar velocity dispersions and the rotation curves we
have constructed equilibrium models for the galactic disks in each galaxy and
analyzed the dynamics of the spiral perturbations using linear global modal
analysis and nonlinear hydrodynamical simulations. The theory reproduces
qualitatively the observed properties of the spiral arms in the galactic disks.
Namely the theory predicts observed grand-design spiral structure in the galaxy
NGC 1566, the tightly-wound spirals in galaxies NGC 488 and NGC 2985, the
two-armed spiral pattern with the third spiral arm in the galaxy NGC 628, and
the multi-armed spiral structure in the galaxies NGC 3938 and NGC 6503. In
general, more massive disks are dominated by two-armed spiral modes. Disks with
lower mass, and with lower velocity dispersion are simultaneously unstable for
spiral modes with different numbers of arms, which results in a more
complicated pattern.


title:
Rotational Spectroscopy of PAHs: Acenaphthene, Acenaphthylene and
  Fluorene

abstract:
  Pure rotational spectra of three polycyclic aromatic hydrocarbons -
acenaphthene, acenaphthylene and fluorene - have been obtained by Fourier
transform microwave spectroscopy of a molecular beam and subsequently by
millimeter wave absorption spectroscopy for acenaphthene and fluorene. The data
presented here will be useful for deep radio astronomical searches for PAHs
employing large radio telecopes.


title:
Very cold and massive cores near ISOSS J18364-0221: Implications for the
  initial conditions of high-mass star-formation

abstract:
  We report the discovery of two very cold and massive molecular cloud cores in
the region ISOSS J18364-0221. The object has been identified by a systematic
search for very early evolutionary stages of high-mass stars using the 170
micron ISOPHOT Serendipity Survey (ISOSS). Submm continuum and molecular line
measurements reveal two compact cores within this region. The first core has a
temperature of 16.5 K, shows signs of ongoing infall and outflows, has no NIR
or MIR counterpart and is massive enough (M ~ 75 M_sun) to form at least one O
star with an associated cluster. It is therefore considered a candidate for a
genuine high-mass protostar and a high-mass analog to the Class 0 objects. The
second core has an average gas and dust temperature of only ~ 12 K and a mass
of M ~ 280 M_sun. Its temperature and level of turbulence are below the values
found for massive cores so far and are suggested to represent the initial
conditions from which high-mass star formation occurs.


title:
On the accumulation of solid bodies in global turbulent protoplanetary
  disc models

abstract:
  We study the migration of solid bodies in turbulent protoplanetary accretion
discs by means of global MHD simulations. The bodies range in size from 5
centimetres up to 1 metre, and so include objects whose migration is expected
to be the most rapid due to gas drag interaction with the disc. As they drift
inward through the disc, some of them are trapped in regions where gas pressure
maxima are created by long lived anticyclonic vortices. This accumulation is
very efficient, locally increasing the dust--to--gas ratio by a factor > 100 in
some cases. We discuss the possible implications of this result for theories of
planet formation.


title:
Some comments on the note "Some comments on the paper 'Filter design for
  the detection of compact sources based on the Neyman-Pearson detector' by M.
  Lopez-Caniego et. al (2005, MNRAS 359, 993)" by R. Vio and P. Andreani
  (astroph/0509394)

abstract:
  In this note we stress the necessity of a careful check of the arguments used
by Vio & Andreani (2005) (VA hereinafter) to criticise the superior performance
of the biparametric scale adaptive filter (BSAF) with respect to the classic
matched filter (MF) in the detection of sources on a random Gaussian
background. In particular, we point out that a defective reading and
understanding of previous works in the literature (Rice 1954; Barreiro et al.
2003; Lopez-Caniego et al. 2005) leads the authors of VA to the derivation of
an incorrect formula and to some misleading conclusions.


title:
Fundamental limitations on Earth-like planet detection with Extremely
  Large Telescopes

abstract:
  We analyse the fundamental limitations for the detection of extraterrestrial
planets with Extremely Large Telescopes. For this task, a coronagraphic device
combined to a very high order wavefront correction system is required but not
sufficient to achieve the $10^{-10}$ contrast level needed for detecting an
Earth-like planet. The stellar residuals left uncorrected by the wavefront
correction system need to be calibrated and subtracted. In this paper, we
consider a general model including the dynamic phase aberrations downstream the
wavefront correction system, the static phase aberrations of the instrument and
some differential aberrations provided by the calibration unit. A rather
optimistic case of a filled circular pupil and of a perfect coronagraph is
elsewhere assumed. As a result of the analytical study, the limitation mostly
comes from the static aberrations. Using numerical simulations we confirm this
result and evaluate the requirements in terms of phase aberrations to detect
Earth-like planets on Extremely Large Telescopes.


title:
Red Variables in Globular Clusters: Comparison with the Bulge and the
  LMC

abstract:
  We are conducting a project aimed at surveys and repeated observations of red
variables (or long-period variables) in globular clusters. Using the
IRSF/SIRIUS near-infrared facility located at South Africa, we are observing
145 globular clusters that are accessible from the site. In this contribution,
we present our observations and preliminary results. We have discovered many
red variables, especially in the Bulge region, whose memberships to the
clusters remain to be confirmed. Using a sample of all red variables (both
already known and newly discovered ones) in globular clusters except those
projected to the Bulge region, we produce a log P-K diagram and compare it with
those for the Bulge and the Large Magellanic Cloud. A prominent feature is that
the bright part of overtone-pulsators' sequence (B+ and C') is absent.


title: A multi-wavelength model of galaxy formation

abstract:
  We present new results from a multi-wavelength model of galaxy formation,
which combines a semi-analytical treatment of the formation of galaxies within
the CDM framework with a sophisticated treatment of absorption and emission of
radiation by dust. We find that the model, which incorporates a top-heavy IMF
in bursts, agrees well with the evolution of the rest-frame far-UV luminosity
function over the range z=0-6, with the IR number counts in all bands measured
by SPITZER, and with the observed evolution of the mid-IR luminosity function
for z=0-2.


title: The Nature of Light Variations of the He-Strong CP Star HD 37776

abstract:
  We calculated spectral energy distribution of the helium strong chemically
peculiar star HD 37776 using adequate model atmospheres. We show that the
chemical peculiarity influences the stellar energy distribution. Consequently,
spots of peculiar chemical composition on the surface of a rotating star may
cause detectable light variations of the star. However, the observed light
variations are not likely caused by an uneven surface distribution of helium,
but may be due to spots of metals (mainly carbon).


title:
The Effect of Coherent Structures on Stochastic Acceleration in MHD
  Turbulence

abstract:
  We investigate the influence of coherent structures on particle acceleration
in the strongly turbulent solar corona. By randomizing the Fourier phases of a
pseudo-spectral simulation of isotropic MHD turbulence (Re $\sim 300$), and
tracing collisionless test protons in both the exact-MHD and phase-randomized
fields, it is found that the phase correlations enhance the acceleration
efficiency during the first adiabatic stage of the acceleration process. The
underlying physical mechanism is identified as the dynamical MHD alignment of
the magnetic field with the electric current, which favours parallel
(resistive) electric fields responsible for initial injection. Conversely, the
alignment of the magnetic field with the bulk velocity weakens the acceleration
by convective electric fields $- \bfu \times \bfb$ at a non-adiabatic stage of
the acceleration process. We point out that non-physical parallel electric
fields in random-phase turbulence proxies lead to artificial acceleration, and
that the dynamical MHD alignment can be taken into account on the level of the
joint two-point function of the magnetic and electric fields, and is therefore
amenable to Fokker-Planck descriptions of stochastic acceleration.


title: VLA Observations of a New Population of Blazars

abstract:
  We present the first deep VLA radio images of flat-spectrum radio quasars
(FSRQ) with multiwavelength emission properties similar to those of BL Lacs
with synchrotron X-rays. Our observations of twenty-five of these sources show
that their radio morphologies are similar to those of other radio quasars.
However, their range of extended powers is more similar to that of BL Lacertae
objects (BL Lacs) and extends down to the low values typical of FR I radio
galaxies. Five out of our nine lobe-dominated sources have extended radio
powers in the range typical of both FR I and FR II radio galaxies, but their
extended radio structure is clearly FR II-like. Therefore, we have not yet
found a large population of radio quasars hosted by FR Is. Two thirds of our
sources have a core-dominated radio morpholgy and thus X-rays likely dominated
by the jet. We find that their ratios of radio core to total X-ray luminosity
are low and in the regime indicative of synchrotron X-rays. This result shows
that also blazars with strong emission lines can produce jets of high-energy
synchrotron emission and undermines at least in part the ``blazar sequence''
scenario which advocates that particle Compton cooling by an external radiation
field governs the frequency of the synchrotron emission peak.


title: Non-Gaussian perturbations from multi-field inflation

abstract:
  We show how the primordial bispectrum of density perturbations from inflation
may be characterised in terms of manifestly gauge-invariant cosmological
perturbations at second order. The primordial metric perturbation, zeta,
describing the perturbed expansion of uniform-density hypersurfaces on large
scales is related to scalar field perturbations on unperturbed (spatially-flat)
hypersurfaces at first- and second-order. The bispectrum of the metric
perturbation is thus composed of (i) a local contribution due to the
second-order gauge-transformation, and (ii) the instrinsic bispectrum of the
field perturbations on spatially flat hypersurfaces. We generalise previous
results to allow for scale-dependence of the scalar field power spectra and
correlations that can develop between fields on super-Hubble scales.


title: On the nature of the ultraluminous X-ray transient in Cen~A (NGC 5128)

abstract:
  We combine 9 ROSAT, 9 Chandra, and 2 XMM-Newton observations of the Cen~A
galaxy to obtain the X-ray light curve of 1RXH J132519.8-430312 (=CXOU
J132519.9$-$430317) spanning 1990 to 2003. The source reached a peak 0.1-2.4
keV flux F_X>10^{-12} ergs cm^{-2} s^{-1} during a 10~day span in 1995 July.
The inferred peak isotropic luminosity of the source therefore exceeded 3
10^{39} ergs s^{-1}, which places the source in the class of ultra-luminous
X-ray sources. Coherent pulsations at 13.264 Hz are detected during a second
bright episode (F_X >3 times 10^{-13} ergs cm^{-2} s^{-1}) in 1999 December.
The source is detected and varies significantly within three additional
observations but is below the detection threshold in 7 observations. The X-ray
spectrum in 1999 December is best described as a cut-off power law or a
disk-blackbody (multi-colored disk). We also detect an optical source, m_F555W
~ 24.1 mag, within the Chandra error circle of 1RXH J132519.8-430312 in HST
images taken 195~days before the nearest X-ray observation. The optical
brightness of this source is consistent with a late O or early B star at the
distance of Cen A. If the optical source is the counterpart, then the X-ray and
optical behavior of 1RXH J132519.8-430312 are similar to the transient Be/X-ray
pulsar A 0538-66.


title: The initial mass distribution of the M82 star cluster system

abstract:
  We explore whether we can constrain the shape of the INITIAL mass
distribution of the star cluster population in M82's ~1 Gyr-old post-starburst
region "B", in which the present-day cluster mass function (CMF) is closely
approximated by a log-normal distribution. We conclude that the M82 B initial
CMF must have had a mean mass very close to that of the "equilibrium" CMF of
Vesperini (1998). Consequently, if the presently observed M82 B CMF has
remained approximately constant since its formation, as predicted, then the
INITIAL CMF must have been characterized by a mean mass that was only slightly
larger than the present mean mass. From our detailed analysis of the expected
evolution of CMFs, we conclude that our observations of the M82 B CMF are
inconsistent with a scenario in which the 1 Gyr-old cluster population
originated from an initial power-law mass distribution. Our conclusion is
supported by arguments related to the initial density in M82 B, which would
have been unphysically high if the present cluster population were the remains
of an initial power-law distribution.


title: Off-Axis Properties of Short Gamma-Ray Bursts

abstract:
  Based on recent models of relativistic jet formation by thermal energy
deposition around black hole-torus systems, the relation between the on- and
off-axis appearance of short, hard gamma-ray bursts (GRBs) is discussed in
terms of energetics, duration, average Lorentz factor, and probability of
observation, assuming that the central engines are remnants of binary neutron
star or neutron star-black hole mergers. As a consequence of the interaction
with the torus matter at the jet basis and the subsequent expansion of the jets
into an extremely low-density environment, the collimated ultrarelativistic
outflows possess flat core profiles with only little variation of
radially-averaged properties, and are bounded by very steep lateral edges.
Owing to the rapid decrease of the isotropic-equivalent energy near the jet
edges, the probability of observing the lateral, lower Lorentz factor wings is
significantly reduced and most short GRBs should be seen with on-axis-like
properties. Taking into account cosmological and viewing angle effects,
theoretical predictions are made for the short-GRB distributions with redshift
z, fluence, and isotropic-equivalent energy. The observational data for short
bursts with determined redshifts are found to be compatible with the
predictions only if either the intrinsic GRB rate density drops rapidly at z>1,
or a large number of events at z>1 are missed, implying that the subenergetic
GRB 050509b was an extremely rare low-fluence event with detectable photon flux
only because of its proximity and shortness. It appears unlikely that GRB
050509b can be explained as an off-axis event. The detection of short GRBs with
small Lorentz factors is statistically disfavored, suggesting a possible reason
for the absence of soft short bursts in the duration-hardness diagram.


title: Intra-group Light in Hickson Compact Groups

abstract:
  We have analyzed the intra-group light component of 3 Hickson Compact Groups
(HCG 79, HCG 88 and HCG 95) with detections in two of them: HCG 79, with
$46\pm11%$ of the total $B$ band luminosity and HCG 95 with $11\pm26%$. HCG 88
had no component detected. This component is presumably due to tidally stripped
stellar material trapped in the group potential and represents an efficient
tool to determine the stage of dynamical evolution and to map its gravitational
potential. To detect this low surface brightness structure we have applied the
wavelet technique OV\_WAV, which separates the different components of the
image according to their spatial characteristic sizes.


title: Stellar Variability in the Sub-Horizontal Branch Region of the LMC

abstract:
  We present the initial results from an in-depth re-examination of the MACHO
project Large Magellanic Cloud database to identify and characterize stellar
variability near the intersection of the instability strip and the main
sequence. This dataset's long time-series and uniform photometry is an
unprecedented resource for describing the frequency and regions of incidence of
various radial and non-radial modes of excitation. The raw MACHO photometry has
been investigated to identify factors responsible for most of the residual
photometric variance and increase the sensitivity to small amplitudes. We
present details of the search method used, the Delta Scuti variables detected
thus far and discuss the implications for the completed survey.


title: The formation history of elliptical galaxies

abstract:
  We take advantage of the largest high-resolution simulation of cosmic
structure growth ever carried out -- the Millennium Simulation of the
concordance LambdaCDM cosmogony -- to study how the star formation histories,
ages and metallicities of elliptical galaxies depend on environment and on
stellar mass. We concentrate on a galaxy formation model which is tuned to fit
the joint luminosity/colour/morphology distribution of low redshift galaxies.
Massive ellipticals in this model have higher metal abundances, older
luminosity-weighted ages, shorter star formation timescales, but lower assembly
redshifts than less massive systems. Within clusters the typical masses, ages
and metal abundances of ellipticals are predicted to decrease, on average, with
increasing distance from the cluster centre. We also quantify the effective
number of progenitors of ellipticals as a function of present stellar mass,
finding typical numbers below 2 for M* < 10^{11} Msun, rising to about 5 for
the most massive systems. These findings are consistent with recent
observational results that suggest ``down-sizing'' or ``anti-hierarchical''
behaviour for the star formation history of the elliptical galaxy population,
despite the fact that our model includes all the standard elements of
hierarchical galaxy formation and is implemented on the standard, LambdaCDM
cosmogony.


title: Discovery of PAHs in the Halo of NGC 5907

abstract:
  We have used sensitive archival data from the Infrared Space Observatory
(ISO) to make maps of the edge-on low SFR galaxy, NGC 5907, in 6 different MIR
bands: LW2, LW5, LW6, LW7, LW8, and LW10, covering the spectrum from 6.5 to
15.0 microns and including several narrow bands that isolate the infrared
aromatic spectral features commonly referred to as PAHs. Most of the MIR
emission is dominated by PAHs and it is likely that emission from VSGs
contribute only negligibly except in the broad IRAS-equivalent band. The flux
ratios are typical of galaxies with low SFRs or quiesent regions within
galaxies (e.g M~83) and a very high PAH/continuum ratio is observed. The PAH
emission follows the CO distribution and also shows some correlation within the
disk with the lambda 850 micron distribution. However, the PAH emission also
reaches larger galactocentric radii than the CO and other correlations suggest
that the PAHs are also more widespread. A significant new discovery is the
presence of PAHs in the halo of the galaxy. In the narrow bands that isolate
single PAH features, the emission shows structure similar to high latitude
features seen in other galaxies in other tracers. The features extend as far as
6.5 kpc from the plane but scale heights of 3.5 kpc are more typical. The
(lambda 11.3/lambda7.7) ratio also appears to increase with distance from the
major axis. To our knowledge, this is the first time PAHs have been seen in the
halo of an external galaxy. Just as significantly, they are seen in a low SFR
galaxy, suggesting that strong SNe and winds are not necessary for these large
molecules to reach high latitudes.


title: Boundary Inflation and the WMAP Data

abstract:
  Inflation in a five-dimensional brane world model with two boundary branes is
studied. We make use of the moduli space approximation whereby the low energy
theory reduces to a four-dimensional biscalar-tensor gravity plus a minimally
coupled scalar field. After a detailed analysis of the inflationary solutions,
we derive the evolution equations of the linear perturbations separating the
adiabatic mode from two entropy modes. We then examine the primordial scalar
and tensor power spectra and show that their tilt depends on the scalar-tensor
coupling constant. Finally, the induced CMB anisotropies are computed and we
present a Monte Carlo Markov Chains exploration of the parameter space using
the first year WMAP data. We find a marginalized probability bound for the
associated Eddington parameter at the end of inflation 1 - gamma < 0.002, at
95% confidence level. This suggests that future CMB data could provide crucial
information helping to distinguish scalar-tensor and standard inflationary
scenarios.


title:
Investigating disk evolution: A high spatial resolution mid-infrared
  survey of T Tauri stars

abstract:
  We present a high spatial resolution, 10-20 micron survey of 65 T Tauri
binary stars in Taurus, Ophiuchus, and Corona Australis using the Keck 10 m
telescopes. Designed to probe the inner ~1 AU region of the circumstellar disks
around the individual stellar components in these binary systems, this study
increases the number of binaries with spatially resolved measurements at 10
micron by a factor of ~5. Combined with resolved near-infrared photometry and
spectroscopic accretion diagnostics, we find that ~10% of stars with a
mid-infrared excess do not appear to be accreting. In contrast to an actively
accreting disk system, these passive disks have significantly lower
near-infrared colors that are, in most cases, consistent with photospheric
emission, suggesting the presence of an inner disk hole. In addition, there
appears to be a spectral type/mass dependence associated with the presence of a
passive disk, with all passive disks occurring around M type stars. The
possibility that the passive disks are caused by the presence of an as yet
undetected companion at a small separation (0.3-3 AU) is possible for any
individual system, however, it cannot account for the spectral type dependence
of the passive disk sample as a whole. We propose that these passive disks
represent a subset of T Tauri stars that are undergoing significant disk
evolution. The fraction of observed passive disks and the observed spectral
type dependence can both be explained by models of disk evolution that include
disk photoevaporation from the central star. (abridged).


title: High energy neutrinos from a slow jet model of core collapse supernovae

abstract:
  It has been hypothesized recently that core collapse supernovae are triggered
by mildly relativistic jets following observations of radio properties of these
explosions. Association of a jet, similar to a gamma-ray burst jet but only
slower, allows shock acceleration of particles to high energy and non-thermal
neutrino emission from a supernova. Detection of these high energy neutrinos in
upcoming kilometer scale Cherenkov detectors may be the only direct way to
probe inside these astrophysical phenomena as electromagnetic radiation is
thermal and contains little information. Calculation of high energy neutrino
signal from a simple and slow jet model buried inside the pre-supernova star is
reviewed here. The detection prospect of these neutrinos in water or ice
detector is also discussed in this brief review. Jetted core collapse
supernovae in nearby galaxies may provide the strongest high energy neutrino
signal from point sources.


title: Compact HI clouds at high forbidden velocities in the inner Galaxy

abstract:
  The VLA Galactic Plane Survey (VGPS) of the first Galactic quadrant was
searched for HI emission with velocities well above the maximum velocity
allowed by Galactic rotation. A sample of 17 small fast-moving clouds was
identified. The distribution of the ensemble of clouds in longitude and
velocity indicates that the clouds are part of the Galactic disk, despite their
large forbidden velocity. The median angular diameter of the clouds detected in
the VGPS is 3.4 arcminutes. These clouds would not be noticed in previous low
resolution surveys because of strong beam dilution. Assuming each cloud is
located at the tangent point, a median cloud has a diameter of 10 pc, HI mass
of 60 M_sun, and a velocity more than 25 km/s beyond the local terminal
velocity derived from 12CO observations. Three clouds in the sample have a
velocity between 50 and 60 km/s in excess of the local terminal velocity. The
longitude distribution of the sample peaks near l = 30 degrees, while the
latitude distribution of the clouds is nearly flat. The observed longitude and
latitude distributions are compared with simulated distributions taking into
account the selection criteria of the cloud search. It is found that the number
of clouds declines with distance from the Galactic center, with an exponential
scale length 2.8 - 8 kpc at the 99% confidence level. We find a lower limit to
the scale height of the clouds of 180 pc (HWHM), but the true value is likely
significantly higher.


title:
SN 2005bf: A Possible Transition Event Between Type Ib/c Supernovae and
  Gamma Ray Bursts

abstract:
  We present u'g'r'i'BV photometry and optical spectroscopy of the Type Ib/Ic
SN 2005bf covering the first ~100 days following discovery. The u'g'BV light
curves displayed a double-peaked morphology, which is among Type Ib/Ic
supernovae. The bolometric light curve indicates that SN 2005bf was a
remarkably luminous event. Spectroscopically, SN 2005bf underwent a unique
transformation from a Type Ic-like event at early times to a typical Type Ib
supernova at later phases. The initial maximum in u'g'BV was accompanied by the
presence in the spectrum of high velocity absorption lines of Fe II, Ca II, and
H I. The photospheric velocity derived from spectra at early epochs was
unusually low compared with ordinary Type Ib supernovae. We describe
one-dimensional computer simulations which attempt to account for these
remarkable properties. The most favored model is that of a very energetic (2 x
10^{51} erg), asymmetric explosion of a massive (8.3 M_sun) Wolf-Rayet WN star
that had lost most of its hydrogen envelope. We speculate that an unobserved
relativistic jet was launched producing a two-component explosion consisting of
1) a polar explosion containing a small fraction of the total mass and moving
at high velocity, and 2) the explosion of the rest of the star. At first, only
the polar explosion is observed, producing the initial maximum and the high
velocity absorption-line spectrum resembling a Type Ic event. At late times,
this fast-moving component becomes optically-thin, revealing the slower-moving
explosion of the rest of the star and transforming the observed spectrum to
that of a typical Type Ib supernova. If this scenario is correct, then SN
2005bf is the best example to date of a transition object between normal Type
Ib/Ic supernovae and gamma ray bursts.


title:
Arecibo Pulsar Survey Using ALFA. I. Survey Strategy and First
  Discoveries

abstract:
  We report results from the initial stage of a long-term pulsar survey of the
Galactic plane using the Arecibo L-band Feed Array (ALFA), a seven-beam
receiver operating at 1.4 GHz with 0.3 GHz bandwidth. The search targets
Galactic latitudes |b| < 5 deg in the longitude ranges 32 deg < l < 77 deg and
168 deg < l < 77 deg. Data discussed here were collected over a 100 MHz
passband centered on 1.42 GHz using a spectrometer that recorded 256 channels
every 64 microsec. In a preliminary, standard period-DM analysis, we have
detected 29 previously known pulsars and discovered 11 new ones. One of these,
with a period of 69 ms and a low characteristic age of 82 kyr, is a plausible
candidate for association with the unidentified EGRET source 3EG J1928+1733.
Another is a non-recycled pulsar in a relativistic binary with orbital period
of 3.98 hr. We also search the data for isolated dispersed pulses, a technique
that yielded discovery of an extremely sporadic radio emitter with a spin
period of 1.2 s. Simulations we have carried out indicate that about 1000 new
pulsars will be found in the ALFA survey. In addition to providing a large
sample for use in population analyses and for probing the magnetoionic
interstellar medium, the survey maximizes the chances of finding rapidly
spinning millisecond pulsars and pulsars in compact binary systems. Our search
algorithms will exploit the multiple data streams from ALFA to discriminate
between radio frequency interference and celestial signals, including pulsars
and possibly new classes of transient radio sources.


title: Dust and the ultraviolet energy distribution of quasars

abstract:
  The ultraviolet energy distribution of quasars shows a sharp steepening of
the continuum shortward of 1000 A (rest-frame). We describe how we came to
consider the possibility that this continuum break might be the result of
absorption by carbon crystallite dust grains.


title: Dust and the far-UV spectral energy distribution of quasars

abstract:
  The spectral energy distribution of quasars shows a sharp steepening of the
continuum shortward of ~ 1100 A. We present a new dust extinction model
consisting of crystalline carbon grains. We analyze the unusual extinction
properties of this dust and proceed to show how the observed UV spectral break
can be successfully modelled by crystalline carbon dust.


title: Nanodiamond dust and the energy distribution of quasars

abstract:
  The spectral energy distribution of quasars shows a sharp steepening of the
continuum shortward of ~ 1100 A. The steepening could be a result of dust
absorption. We present a dust extinction model which considers crystalline
carbon grains and compare it with SMC-like dust extinction consisting of a
mixture of silicate grains with graphite or amorphous carbon grains. We show
that the sharp break seen in individual quasar spectra of intermediate redshif
\~ 1-2 can be reproduced by dust absorption provided the extinction curve
consists of nanodiamonds, composed of terrestial cubic diamonds or of diamonds
similar to the presolar nanodiamonds found in primitive meteorites.


title: Redshifts in the Southern Abell Redshift Survey Clusters. I. The Data

abstract:
  The Southern Abell Redshift Survey contains 39 clusters of galaxies with
redshifts in the range 0.0 < z < 0.31 and a median redshift depth of z =
0.0845. SARS covers the region 0 < decl < -65 deg, R.A. < 5h, R.A. > 21h (while
avoiding the LMC and SMC) with b > 40. Cluster locations were chosen from the
Abell and Abell-Corwin-Olowin catalogs while galaxy positions were selected
from the Automatic Plate Measuring Facility galaxy catalog with
extinction-corrected magnitudes in the range 15 <= b_j < 19. SARS utilized the
Las Campanas 2.5 m duPont telescope, observing either 65 or 128 objects
concurrently over a 1.5 sq deg field. New redshifts for 3440 galaxies are
reported in the fields of these 39 clusters of galaxies.


title: Detection of a huge explosion in the early Universe

abstract:
  Gamma-ray Bursts (GRBs) are bright flashes of high energy photons that can
last from about 10 milliseconds to 10 minutes. Their origin and nature have
puzzled the scientific community for about 25 years until 1997, when the first
X-ray afterglows of long (> 2 s duration) bursts were detected and the first
optical and radio counterparts were found. These measurements established that
long GRBs are typically at high redshift (z 1.6) and are in sub-luminous
star-forming host galaxies. They are likely produced in core-collapse
explosions of a class of massive stars that give rise to highly relativistic
jets (collapsar model). Internal inhomogeneities in the velocity field of the
relativistic expanding flow lead to collisions between fast moving and slow
moving fluid shells and to the formation of internal shock waves. These shocks
are believed to produce the observed prompt emission in the form of irregularly
shaped and spaced pulses of gamma-rays, each pulse corresponding to a distinct
internal collision. The expansion of the jet outward into the circumstellar
medium is believed to give rise to ``external'' shocks, responsible for
producing the smoothly fading afterglow emission seen in the X-ray, optical and
radio bands. Here we report on the gamma-ray and x-ray observation of the most
distant gamma-ray burst ever observed: its redshift of 6.29 translates to a
distance of 13 billion light-years from Earth, corresponding to a time when the
Universe was just 700 million to 750 million years old. The discovery of a
gamma-ray burst at such a large redshift implies the presence of massive stars
only 700 million years after the Big Bang. The very high redshift bursts
represent a good way to study the re-ionization era soon after the Universe
came out of the Dark Ages.


title: AM 1934-563: A giant spiral polar-ring galaxy in a triplet

abstract:
  We have observed the emission-line kinematics and photometry of a southern
triplet of galaxies. The triplet contains a giant spiral galaxy AM 1934-563
which optical structure resembles a polar-ring galaxy: distorted spiral disk,
seen almost edge-on, and a faint large-scale (45 kpc in diameter) warped
structure, inclined by 60^o-70^o with respect to the disk major axis. The
triplet shows relatively small velocity dispersion (69 km/s) and a large
crossing time (0.17 in units of the Hubble time). The disk of AM 1934-563
demonstrates optical colors typical for an early-type spirals, strong radial
color gradient, and almost exponential surface brightness distribution with an
exponential scale-length value of 3.1 kpc (R passband). The galaxy shows a
maximum rotation velocity of about 200 km/s and it lies close to the
Tully-Fisher relation for spiral galaxies. The suspected polar ring is faint
(\mu(B) > 24) and strongly warped. Its total luminosity comprises (10-15)% of
the total luminosity of AM 1934-563. We then try to model this system using
numerical simulations, and study its possible formation mechanisms. We find
that the most robust model, that reproduces the observed characteristics of the
ring and the host galaxy, is the tidal transfer of mass from a massive gas-rich
donor galaxy to the polar ring. The physical properties of the triplet of
galaxies are in agreement with this scenario.


title:
Infrared Photometry and Evolution of Mass-Losing AGB Stars I. Carbon
  Stars Revisited

abstract:
  As part of a reanalysis of galactic Asymptotic Giant Branch (AGB) stars at
infrared (IR) wavelengths, we discuss a sample (357) of carbon stars for which
mass loss rates, near-IR photometry and distance estimates exist. For 252
sources we collected mid-IR fluxes from the MSX (6C) and the ISO-SWS
catalogues. Most stars have spectral energy distributions up to 21 microns, and
some (1/3) up to 45 microns. This wide wavelength coverage allows us to obtain
reliable bolometric magnitudes. The properties of our sample are discussed with
emphasis on about 70 stars with astrometric distances. We show that mid-IR
fluxes are crucial to estimate the magnitude of stars with dusty envelopes. We
construct HR diagrams and show that the luminosities agree fairly well with
model predictions based on the Schwarzschild's criterion, contrary to what is
widely argued in the literature. A problem with the brightness of C stars does
not appear to exist. From the relative number of Mira and Semiregular
C-variables, we argue that the switch between these classes is unlikely to be
connected to thermal pulses. The relevance of the two populations varies with
the evolution, with Miras dominating the final stages. We also analyze mass
loss rates, which increase for increasing luminosity, but with a spread that
probably results from a dependence on a number of parameters (like e.g.
different stellar masses and different mechanisms powering stellar winds).
Instead, mass loss rates are well monitored by IR colours, especially if
extended to 20 microns and beyond, where AGB envelopes behave like black
bodies. From these colours the evolutionary status of various classes of C
stars is discussed.


title:
Power Spectrum of Cosmic Momentum Field Measured from the SFI Galaxy
  Sample

abstract:
  We have measured the cosmic momentum power spectrum from the peculiar
velocities of galaxies in the SFI sample. The SFI catalog contains field spiral
galaxies with radial peculiar velocities derived from the I-band Tully-Fisher
relation. As a natural measure of the large-scale peculiar velocity field, we
use the cosmic momentum field that is defined as the peculiar velocity field
weighted by local number of galaxies. We have shown that the momentum power
spectrum can be derived from the density power spectrum for the constant linear
biasing of galaxy formation, which makes it possible to estimate \beta_S =
\Omega_m^{0.6} / b_S parameter precisely where \Omega_m is the matter density
parameter and b_S is the bias factor for optical spiral galaxies. At each
wavenumber k we estimate \beta_S(k) as the ratio of the measured to the derived
momentum power over a wide range of scales (0.026 h^{-1}Mpc <~ k <~ 0.157
h^{-1}Mpc) that spans the linear to the quasi-linear regimes. The estimated
\beta_S(k)'s have stable values around 0.5, which demonstrates the constancy of
\beta_S parameter at scales down to 40 h^{-1}Mpc. We have obtained
\beta_S=0.49_{-0.05}^{+0.08} or \Omega_m = 0.30_{-0.05}^{+0.09} b_S^{5/3}, and
the amplitude of mass fluctuation as
\sigma_8\Omega_m^{0.6}=0.56_{-0.21}^{+0.27}. The 68% confidence limits include
the cosmic variance. We have also estimated the mass density power spectrum.
For example, at k=0.1047 h Mpc^{-1} (\lambda=60 h^{-1}Mpc) we measure
\Omega_m^{1.2} P_{\delta}(k)=(2.51_{-0.94}^{+0.91})\times 10^3 (h^{-1}Mpc)^3,
which is lower compared to the high-amplitude power spectra found from the
previous maximum likelihood analyses of peculiar velocity samples like Mark
III, SFI, and ENEAR.


title: Primordial Molecular Emission in Population III Galaxies

abstract:
  We study formation of molecules in primordial prestellar clumps and evaluate
the line luminosities to assess detectability by next-generation facilities. If
the initial H_2 fraction is sufficiently high, HD becomes an important coolant
in the clumps. The luminosity from such HD cooling clumps is lower than that
from H_2 cooling ones because of lower temperature (<100K). As for Li
reactions, we include the three-body LiH formation approximately. The Li
molecular fraction remains very low (<10^{-3}) throughout the evolution owing
to the high dissociative reaction rate of LiH +H -> Li + H_2. LiH does not
become an important coolant in any density range. The luminous emission lines
from the prestellar cores include H_2 rovibrational lines: 1-0 Q(1), 1-0 O(3),
1-0 O(5), and pure rotational lines: 0-0 S(3), 0-0 S(4), 0-0 S(5). The
next-generation facilities SPICA and JWST are able to detect H_2 emission in a
large pre-galactic cloud that forms metal-free stars at a high rate of \sim
10^3 M_s/yr at redshift z<10. We also derive an analytical expression for the
luminosity that reproduces the numerical results.


title:
Photometry and Spectroscopy of Old, Outer Disk Star Clusters: vdB-Hagen
  176, Berkeley 29 and Saurer 1

abstract:
  It has been previously proposed that some distant open clusters in the Milky
Way may have been accreted during a dwarf galaxy merger, perhaps associated
with the same event that led to the formation of the Galactic anticenter
stellar structure (GASS), also known as the ``Monoceros Ring''. We have
obtained VI and Washington+DDO51 photometric and medium resolution (R ~ 8000)
multi-fiber spectroscopic data for the three distant old open clusters Berkeley
29, Saurer 1, and vdB-Hagen 176 (BH 176). These clusters are spatially
coincident with GASS, but radial velocities and spectroscopic metallicities had
not been available during previous studies of the GASS candidate cluster
system. Similar data for the clusters Berkeley 20 and Berkeley 39 have been
obtained for calibration purposes. We provide the first {\it reliable} radial
velocity for BH 176 (V_{helio} = 11.2 +/- 5.3 km/s). We also find that
V_{helio} = +95.4 +/- 3.6 and +28.4 +/- 3.6 km/s, for Saurer 1(A) and Berkeley
29, respectively. We show that alpha-enhanced isochrones, while
spectroscopically motivated, provide a poor fit to Be29 in contrast to previous
findings. We find that the clusters Berkeley 29 and Saurer 1 are consistent
with the previously reported characteristics for GASS candidate clustersand the
GASS stellar stream as derived from M-giant observations. However, the radial
velocity and photometric metallicity ([Fe/H] ~ 0.0 dex) for BH 176 suggests
that a connection of this cluster with the putative GASS cluster system is
unlikely. We reassess the age-metallicity relation for the most likely members
of the GASS clusters system for which spectroscopic metallicities are now
available.


title:
Prediction of the Virgo axis anisotropy: CMB radiation illuminates the
  nature of things

abstract:
  Recent findings of the anisotropy in the Cosmic Microwave Background (CMB)
radiation are confusing for standard cosmology. Remarkably, this fact has been
predicted several years ago in the framework of our model of the physical
world. Moreover, in exact agreement with our prediction the CMB has a preferred
direction towards the Virgo Cluster. The transpired structure of the CMB shows
workings of the suggested model of the physical world. Comprising the
information processes of Nature, this model presents a high-tech version of the
previous low-tech developments for mechanical ether and quantum vacuum. In the
current model, the phenomenon of Life turns up as a collective effect on the
"Internet of the Physical Universe" using DNA structures for access codes. Most
convincingly, this construction points to a harmful analogy with so-called
"identity theft" - improper manipulations with DNA of individual organisms can
destroy these organisms from a remote location without any physical contact.
Appearing incredible, such a possibility creates a superlative Experimentum
Crucis. In a broad sense, this surmised biological effect is intimately related
to the cosmological prediction of the structurization of the CMB, but it is
more compelling.


title: Formation of intracluster globular clusters

abstract:
  We first present the results of numerical simulations on formation processes
and physical properties of old globular clusters (GCs) located within clusters
of galaxies (``intracluster GCs'') and in between clusters of galaxies
(``intercluster GCs''). Our high-resolution cosmological simulations with
models of GC formation at high redshifts ($z>6$) show that about 30 % of all
GCs in a rich cluster can be ragarded as intracluster GCs that can freely drift
being trapped by gravitational potential of the cluster rather than by the
cluster member galaxies. The radial surface density profiles of the simulated
intracluster GCs are highly likely to be flatter than those of GCs within
cluster member galaxies. We also find that about 1% of all GCs formed before
$z>6$ are not located within any virialized halos and can be regarded as
``intercluster'' (or ``intergalactic'') GCs. We discuss the dependences of
physical properties of intracluster and intercluster GCs on the initial density
profiles of GCs within low-mass dark matter halos at high redshifts ($z>6$).


title: Antonov problem and quasi-equilibrium states in N-body system

abstract:
  In this paper, a quantitative characterization for the evolutionary sequence
of stellar self-gravitating system is investigated, focusing on the
pre-collapse stage of the long-term dynamical evolution. In particular, we
consider the quasi-equilibrium behaviors of the N-body systems in the setup of
the so-called Antonov problem, i.e., self-gravitating N-body system confined in
an adiabatic wall and try to seek a possible connection with thermostatistics
of self-gravitating systems. For this purpose, a series of long-term N-body
simulations with various initial conditions are performed. We found that a
quasi-equilibrium sequence away from the thermal equilibrium can be
characterized by the one-parameter family of the stellar models. Especially,
the stellar polytropic distribution satisfying the effective equation of state
$P\propto\rho^{1+1/n}$ provides an excellent approximation to the evolutionary
sequence of the N-body system. Based on the numerical results, we discuss a
link between the quasi-equilibrium state and the generalized thermostatistics
by means of the non-extensive entropy.


title:
High angular resolution N-band observation of the silicate carbon star
  IRAS08002-3803 with the VLTI/MIDI instrument

abstract:
  We present the results of N-band spectro-interferometric observations of the
silicate carbon star IRAS08002-3803 with the MID-infrared Interferometric
instrument (MIDI) at the Very Large Telescope Interferometer (VLTI) of the
European Southern Observatory (ESO). The observations were carried out using
two unit telescopes (UT2 and UT3) with projected baseline lengths ranging from
39 to 47 m. Our observations of IRAS08002-3803 have spatially resolved the
dusty environment of a silicate carbon star for the first time and revealed an
unexpected wavelength dependence of the angular size in the N band: the
uniform-disk diameter is found to be constant and ~36 mas (72 Rstar) between 8
and 10 micron, while it steeply increases longward of 10 micron to reach ~53
mas (106 Rstar) at 13 micron. Model calculations with our Monte Carlo radiative
transfer code show that neither spherical shell models nor axisymmetric disk
models consisting of silicate grains alone can simultaneously explain the
observed wavelength dependence of the visibility and the spectral energy
distribution (SED). We propose that the circumstellar environment of
IRAS08002-3803 may consist of two grain species coexisting in the disk:
silicate and a second grain species, for which we consider amorphous carbon,
large silicate grains, and metallic iron grains. Comparison of the observed
visibilities and SED with our models shows that such disk models can fairly --
though not entirely satisfactorily -- reproduce the observed SED and N-band
visibilities. Our MIDI observations and the radiative transfer calculations
lend support to the picture where oxygen-rich material around IRAS08002-3803 is
stored in a circumbinary disk surrounding the carbon-rich primary star and its
putative low-luminosity companion.


title: The shock-patterned solar chromosphere in the light of ALMA

abstract:
  Recent three-dimensional radiation hydrodynamic simulations by Wedemeyer et
al. (2004) suggest that the solar chromosphere is highly structured in space
and time on scales of only 1000 km and 20-25 sec, resp.. The resulting pattern
consists of a network of hot gas and enclosed cool regions which are due to the
propagation and interaction of shock fronts. In contrast to many other
diagnostics, the radio continuum at millimeter wavelengths is formed in LTE,
and provides a rather direct measure of the thermal structure. It thus
facilitates the comparison between numerical model and observation. While the
involved time and length scales are not accessible with todays equipment for
that wavelength range, the next generation of instruments, such as the Atacama
Large Millimeter Array (ALMA), will provide a big step towards the required
resolution. Here we present results of radiative transfer calculations at mm
and sub-mm wavelengths with emphasis on spatial and temporal resolution which
are crucial for the ongoing discussion about the chromospheric temperature
structure.


title: Spectroscopy of roAp star pulsation: HD24712

abstract:
  We present results of the radial velocity (RV) analysis of spectroscopic
time-series observations of the roAp star HD24712 (HR1217) which were carried
out simultaneously with the Canadian MOST mini-satellite photometry. Only lines
of the rare-earth elements (REE) show substantial amplitudes of RV pulsations.
Based on new Zeeman measurements we found different shapes of the magnetic
curves derived by using Fe-peak and REE separately. Frequency analysis of the
spectroscopic data showed that the highest amplitude frequencies are the same
in photometry and spectroscopy. Photometric and spectroscopic pulsation curves
are shifted in phase, and the phase shift depends on the atomic species. The
observed distribution of RV pulsation amplitudes and phases with the optical
depth as well as the observed phase lag between luminosity and radius
variations are explained satisfactorily by the model of nonadiabatic nonradial
pulsations of a magnetic star.


title:
The circumstellar environment of Wolf-Rayet stars & Gamma-ray burst
  afterglows

abstract:
  We study the evolution of the circumstellar medium of massive stars. We pay
particular attention to Wolf-Rayet stars that are thought to be the progenitors
of some long Gamma-Ray Bursts. We detail the mass-loss rates we use in our
stellar evolution models and how we estimate the stellar wind speeds during
different phases. With these details we simulate the interactions between the
wind and the interstellar medium to predict the circumstellar environment
around the stars at the time of core-collapse. We then investigate how the
structure of the environment might affect the GRB afterglow. We find that when
the afterglow jet encounters the free-wind to stalled-wind interface that
rebrightening occurs and a bump is seen in the afterglow light curve. However
our predicted positions of this interface are too distant from the site of the
GRB to reach while the afterglow remains observable. The values of the
final-wind density, A_{*}, from our stellar models are similar to the values
inferred from observed afterglow lightcurves and those from observed Wolf-Rayet
stars. However we do not reproduce the lowest observed A_{*} values below 0.3.
For these cases we suggest that the progenitors could have been a WO type
Wolf-Rayet star, be in a close binary or very low metallicity star. Finally we
turn our attention to the matter of stellar wind material producing absorption
lines in the afterglow spectra. We discuss the observational signatures of two
Wolf-Rayet stellar types, WC and WO, in the afterglow lightcurve and spectra.
We also indicate how it may be possible to constrain the initial mass and
metallicity of a GRB progenitor by using the inferred wind density and wind
velocity.


title: Precursors and Main-bursts of Gamma Ray Bursts in a Hypernova Scenario

abstract:
  We investigate a "hypernova" model for gamma-ray bursts (GRBs), i.e., massive
C+O star model with relativistic jets. In this model, non-thermal precursors
can be produced by the "first" relativistic shell ejected from the star. Main
GRBs are produced behind the "first"-shell by the collisions of several
relativistic shells. They become visible to distant observers after the
colliding region becomes optically thin. We examine six selected conditions
using relativistic hydrodynamical simulations and simple analyses.
Interestingly, our simulations show that sub-relativistic $(v \sim 0.8c)$ jets
from the central engine is sufficient to produce highly-relativistic $(\Gamma >
100)$ shells. We find that the relativistic shells from such a star can
reproduce observed GRBs with certain conditions. Two conditions are especially
important. One is the sufficiently long duration of the central engine $ \gsim
100$ sec. The other is the existence of a dense-shell somewhere behind the
"first"-shell. Under these conditions, both the existence and non-existence of
precursors, and long delay between precursors and main GRBs can be explained.


title:
Light variations and angular momentum loss from the He-strong magnetic
  chemically peculiar star HD 37776

abstract:
  We present a principle component analysis of multicolour light variations of
the He-strong magnetic chemically peculiar star HD 37776 and its (O-C) diagram.
The period increase rate found, (dP/dt) / P = 5.5 x 10^{-6}/year, is consistent
with the conception of angular momentum loss through magnetically confined
stellar wind.


title: Template fitting and the large-angle CMB anomalies

abstract:
  We investigate two possible explanations for the large-angle anomalies in the
Cosmic Microwave Background (CMB): an intrinsically anisotropic model and an
inhomogeneous model. We take as an example of the former a Bianchi model (which
leaves a spiral pattern in the sky) and of the latter a background model that
already contains a non-linear long-wavelength plane wave (leaving a stripy
pattern in the sky). We make use of an adaptation of the ``template''
formalism, previously designed to detect galactic foregrounds, to recognize
these patterns and produce confidence levels for their detection. The
``corrected'' maps, from which these patterns have been removed, are free of
anomalies, in particular their quadrupole and octupole are not planar and their
intensities not low. We stress that although the ``template'' detections are
not found to be statistically significant they do correct statistically
significant anomalies.


title:
Separate the Tensor Perturbation From the CMB Temperature Anisotropy
  Power Spectrum

abstract: This paper has been withdrawn.


title:
Constraints on the formation mechanism of the planetary mass companion
  of 2MASS 1207334-393254

abstract:
  In this paper we discuss the nature and the possible formation scenarios of
the companion of the brown dwarf 2MASS 1207334-393254. We initially discuss the
basic physical properties of this object and conclude that, although from its
absolute mass ($5M_{\rm Jup}$), it is a planetary object, in terms of its mass
ratio $q$ and of its separation $a$ with respect to the primary brown dwarf, it
is consistent with the statistical properties of binaries with higher primary
mass. We then explore the possible formation mechanism for this object. We show
that the standard planet formation mechanism of core accretion is far too slow
to form this object within 10 Myr, the observed age of the system. On the other
hand, the alternative mechanism of gravitational instability (proposed both in
the context of planet and of binary formation) may, in principle, work and form
a system with the observed properties.


title: Static Configurations of Dark Energy and Dark Matter

abstract:
  We study static configurations of dark matter coupled to a scalar field
responsible for the dark energy of the Universe. The dark matter is modelled as
a Fermi gas within the Thomas-Fermi approximation. The mass of the dark matter
particles is a function of the scalar field. We analyze the profile of the dark
matter halos in galaxies. In this case our framework is equivalent to the model
of the isothermal sphere. In the presence of a scalar field, the velocity of a
massive object orbiting the galaxy is not of the order of the typical velocity
of the dark matter particles, as in the conventional picture. Instead, it is
reduced by a factor that quantifies the dependence of the dark matter mass on
the scalar field. This has implications for dark matter searches. We derive new
solutions of the Einstein equations which describe compact objects composed of
dark matter. Depending on the scale of the dark matter mass, the size of these
objects can vary between microscopic scales and cosmological distances. We
determine the mass to radius relation and discuss the similarities with
conventional neutron stars and exotic astrophysical objects.


title:
Detector and Telescope Development for ProtoEXIST and Fine Beam
  Measurements of Spectral Response of CZT Detectors

abstract:
  We outline our plan to develop ProtoEXIST, a balloon-borne prototype
experiment for the Energetic X-ray Imaging Survey Telescope (EXIST) for the
Black Hole Finder Probe. EXIST will consist of multiple wide-field hard X-ray
coded-aperture telescopes. The current design of the EXIST mission employs two
types of telescope systems: high energy telescopes (HETs) using CZT detectors,
and low energy telescopes (LETs) using Si detectors. With ProtoEXIST, we will
develop and demonstrate the technologies required for the EXIST HETs. As part
of our development efforts, we also present recent laboratory measurements of
the spectral response and efficiency variation of imaging CZT detectors on a
fine scale (~0.5 mm). The preliminary results confirm the need for multi-pixel
readouts and small inter-pixel gaps to achieve uniform spectral response and
high detection efficiency across detectors.


title:
Monte-Carlo simulations of the expected imaging performance of the EXIST
  high-energy telescope

abstract:
  EXIST is being studied as the Black Hole Finder Probe, one of the 3 Einstein
Probe missions under NASA's Beyond Einstein program. The major science goals
for EXIST include highly sensitive full-sky hard X-ray survey in a very wide
energy band of 5-600 keV. The scientific requirements of wide energy band
(10-600 keV for the High Energy Telescope considered for EXIST) and large field
of view (approximately 130 deg x 60 deg in the current design, incorporating an
array of 18 contiguous very large area coded aperture telescopes) presents
significant imaging challenges. The requirement of achieving high imaging
sensitivity puts stringent limits on the uniformity and knowledge of
systematics for the detector plane. In order to accomplish the ambitious
scientific requirements of EXIST, it is necessary to implement many novel
techniques. Here we present the initial results of our extensive Monte-Carlo
simulations of coded mask imaging for EXIST to estimate the performance
degradation due to various factors affecting the imaging such as the non-ideal
detector plane and bright partially coded sources.


title:
The Rates of type I X-ray Bursts from Transients Observed with RXTE:
  Evidence for Black Hole Event Horizons

abstract:
  We measure the rates of type I X-ray bursts, as a function of the bolometric
luminosity, from a likely complete sample of 37 non-pulsing transients
(1996-2004). Our goals are to test the burst model for neutron stars and to
investigate whether black holes have event horizons. We find 135 type I bursts
in 3.7 Ms of exposure for the neutron-star group, and the burst rate function
is generally consistent with model predictions. However, for the black hole
groups (18 sources), there are no confirmed type I bursts in 6.5 Ms of
exposure, and the upper limits in the burst function are inconsistent with the
model predictions for heavy compact objects with a solid surface. There are
systematic spectral differences between the neutron-star and black-hole groups,
supporting the presumption that physical differences underly the sample
classifications. These results provide indirect evidence that black holes do
have event horizons.


title:
The Morphological Demographics of galaxies in the ACS Hubble Ultra Deep
  Parallel Fields

abstract:
  We present a morphological analysis of distant field galaxies using the deep
ACS images from the public parallel NICMOS observations of the Hubble Ultra
Deep Field obtained in the F435W (B), F606W (V), F775W (i) and F850LP (z)
filters. We morphologically segregate galaxies using a combination of visual
classification and objective machine based selection. We use the Asymmetry (A)
and Central Concentration (C) parameters to characterize galaxies up to
z_AB<25mag. We take advantage of the multicolor dataset and estimate redshifts
for our sample using the Bayesian photometric redshift (BPZ) which enables us
to investigate the evolution of their morphological demographics with redshift.
Using a template fitting model and a maximum likelihood approach, we compute
the star-formation rate (SFR) for galaxies up to z~1.3 and its contributions
from different morphological types. We report that spirals are the main
providers to the total SFR. The E/S0s contribution flattens out at z~1 while
the Irr/Pec populations continuously rise to match the spirals contribution at
z~1.0. We use the i-z and V-i color-magnitude diagrams to constrain the
galaxies' formation histories and find that E/S0s show both a population of
luminous red galaxies in place at z~1.2 and a bluer and fainter population
resembling those of Irr/Pec at similar redshifts.


title:
Could electron-positron annihilation lines in the Galactic center result
  from pulsar winds?

abstract:
  we study the possibility of pulsar winds in the Galactic center (GC) to
produce the 511 keV line. We propose that there may exist three possible
scenarios of pulsar winds as the positron sources: normal pulsars; rapidly
spinning strongly magnetized neutron stars in GRB progenitors; a population of
millisecond pulsars in the Galactic center region. These $e^\pm$pairs could be
trapped in the region by the magnetic field in the GC, and cool through the
synchrotron radiation and Coulomb interactions with the medium. The cooling
timescales are lower than the diffuse timescale of positrons, so low energy
positrons could annihilate directly with electrons into 511 keV photons or form
positronium before annihilation. We find that normal pulsars cannot be a
significant contributor to the positron sources. Although magnetars in the GC
could be potential sources of positrons, their birth rate and birth locations
may impose some problems for this scenario. We believe that the most likely
candidate positron sources in the GC may be a population of millisecond pulsars
in the GC. Our preliminary estimations predict the e$^\pm$ annihilation rate in
the GC is $> 5\times 10^{42}$ s$^{-1}$. Therefore, the $e^\pm$ pairs from
pulsars winds can contribute significantly to the positron sources in the GC.
Furthermore, since the diffusion length of positrons is short, we predict that
the intensity distribution of the annihilation line should follow the
distribution of millisecond pulsars, which should correlate to the mass
distribution in the GC.


title: Receiver control for the Submillimeter Array

abstract:
  Efficient operation of a submillimeter interferometer requires remote
(preferably automated) control of mechanically tuned local oscillators,
phase-lock loops, mixers, optics, calibration vanes and cryostats. The present
control system for these aspects of the Submillimeter Array (SMA) will be
described. Distributed processing forms the underlying architecture and the
software is split between hardware platforms in a leader/follower arrangement.
In each antenna cabin, a serial network of up to ten independent 80C196
microcontroller boards attaches to the real-time PowerPC computer (running
LynxOS). A multi-threaded, gcc-compiled leader program on the PowerPC accepts
top-level requests via remote procedure calls (RPC), subsequently dispatches
tuning commands to the relevant follower microcontrollers, and regularly
reports the system status to optical-fiber-based reflective memory for common
access by the telescope monitor and error reporting system. All serial
communication occurs asynchronously via encoded, variable-length packets. The
microcontrollers respond to the requested commands and queries by accessing
non-volatile, rewriteable lookup-tables (when appropriate) and executing
embedded software that operates additional electronic devices (DACs, ADCs,
etc.). Since various receiver hardware components require linear or rotary
motion, each microcontroller also implements a position servo via a
one-millisecond interrupt service routine which drives a DC-motor/encoder
combination that remains standard across each subsystem.


title:
The Radio Spectrum of TVLM513-46546: Constraints on the Coronal
  Properties of a Late M Dwarf

abstract:
  We explore the radio emission from the M9 dwarf, TVLM513-46546, at multiple
radio frequencies, determining the flux spectrum of persistent radio emission,
as well as constraining the levels of circular polarization. Detections at both
3.6 and 6 cm provide spectral index measurement $\alpha$ (where S$_{\nu}
\propto \nu^{\alpha}$) of $-0.4\pm0.1$. A detection at 20 cm suggests that the
spectral peak is between 1.4 and 5 GHz. The most stringent upper limits on
circular polarization are at 3.6 and 6 cm, with $V/I <$15%. These
characteristics agree well with those of typical parameters for early to mid M
dwarfs, confirming that magnetic activity is present at levels comparable with
those extrapolated from earlier M dwarfs. We apply analytic models to
investigate the coronal properties under simple assumptions of dipole magnetic
field geometry and radially varying nonthermal electron density distributions.
Requiring the spectrum to be optically thin at frequencies higher than 5 GHz
and reproducing the observed 3.6 cm fluxes constrains the magnetic field at the
base to be less than about 500 G. There is no statistically significant
periodicity in the 3.6 cm light curve, but it is consistent with low-level
variability.


title: Pattern Speeds of Spiral Galaxies Using the Tremaine-Weinberg Method

abstract:
  Spiral galaxies displaying molecule-dominated ISMs are potential candidates
for pattern speed determination by the Tremaine-Weinberg (TW) method (1984);
the molecular gas of such galaxies, as traced by CO emission, is argued to
approximately obey the continuity equation on orbital timescales--a key
requirement of the method. We continue our work on this application of the
Tremaine-Weinberg method with pattern speed determinations of several galaxies
using CO emission data cubes from the BIMA SONG survey, wherein the molecular
dominance of each of the three galaxies in our sample (NGC 5457, 5033, and
5055) is established using radial profiles of Wong and Blitz (2002).


title:
A New Definition for the Ca4227 Feature: Is Calcium Really Underabundant
  in Early-type Galaxies?

abstract:
  We have investigated the abundance of calcium in early-type galaxies by
measuring the strength of the Ca I 4227 absorption line in their integrated
spectra. The database used is the large sample of early-type galaxy integrated
spectra in Caldwell, Rose, & Concannon (2003). We have measured Ca abundances
from the Ca I 4227 feature both by using the Lick Ca4227 index and also by
defining a new index, Ca4227_r, that avoids the CN4216 molecular band in the
continuum on the blueward side of the line. With the new index definition we
measure Ca abundances that are systematically ~0.3 dex higher than with the
Lick Ca4227 index. The result is that with the new index definition we obtain
higher [Ca/Fe] abundances in early-type galaxies which are more consistent with
their well known [Mg/Fe] over-abundances. Hence, we suggest that Ca might be
slightly enhanced, relative to Fe, in early-type galaxies.


title:
Numerical Analysis on Standing Accretion Shock Instability with Neutrino
  Heating in the Supernova Cores

abstract:
  We have numerically studied the instability of the spherically symmetric
standing accretion shock wave against non-spherical perturbations. We have in
mind the application to the collapse-driven supernovae in the post bounce
phase, where the prompt shock wave generated by core bounce is commonly
stalled. We take an experimental stand point in this paper. Using spherically
symmetric, completely steady, shocked accretion flows as unperturbed states, we
have clearly observed both the linear growth and the subsequent nonlinear
saturation of the instability. In so doing, we have employed a realistic
equation of state together with heating and cooling via neutrino reactions with
nucleons. We have done a mode analysis based on the spherical harmonics
decomposition and found that the modes with l=1, 2 are dominant not only in the
linear regime, but also after the nonlinear couplings generate various modes
and the saturation occurs. Varying the neutrino luminosity, we have constructed
the unperturbed states both with and without a negative entropy-gradient. We
have found that in both cases the growth of the instability is similar,
suggesting the convection does not play a dominant role, which also appears to
be supported by the recent linear analysis of the convection in accretion flows
by Foglizzo et al. The real part of the eigen frequency seems to be mainly
determined by the advection time rather than by the sound-crossing time.
Whatever the cause may be, the instability is favorable for the shock revival.


title:
GRB 050904 at redshift 6.3: observations of the oldest cosmic explosion
  after the Big Bang

abstract:
  We present optical and near-infrared observations of the afterglow of the
gamma-ray burst GRB 050904. We derive a photometric redshift z = 6.3, estimated
from the presence of the Lyman break falling between the I and J filters. This
is by far the most distant GRB known to date. Its isotropic-equivalent energy
is 3.4x10^53 erg in the rest-frame 110-1100 keV energy band. Despite the high
redshift, both the prompt and the afterglow emission are not peculiar with
respect to other GRBs. We find a break in the J-band light curve at t_b = 2.6
+- 1.0 d (observer frame). If we assume this is the jet break, we derive a
beaming-corrected energy E_gamma = (4-12)x10^51 erg. This limit shows that GRB
050904 is consistent with the Amati and Ghirlanda relations. This detection is
consistent with the expected number of GRBs at z > 6 and shows that GRBs are a
powerful tool to study the star formation history up to very high redshift.


title: Planets in triple star systems--the case of HD188753

abstract:
  We consider the formation of the recently discovered ``hot Jupiter'' planet
orbiting the primary component of the triple star system HD188753. Although the
current outer orbit of the triple is too tight for a Jupiter-like planet to
have formed and migrated to its current location, the binary may have been much
wider in the past. We assume here that the planetary system formed in an open
star cluster, the dynamical evolution of which subsequently led to changes in
the system's orbital parameters and binary configuration. We calculate cross
sections for various scenarios that could have led to the multiple system
currently observed, and conclude that component A of HD188753 with its planet
were most likely formed in isolation to be swapped in a triple star system by a
dynamical encounter in an open star cluster. We estimate that within 500pc of
the Sun there are about 1200 planetary systems which, like Hd188753, have
orbital parameters unfavorable for forming planets but still having a planet,
making it quite possible that the HD188753 system was indeed formed by a
dynamical encounter in an open star cluster.