title: A Possible New Transiting Planet

abstract:
  Recently, 59 low-luminosity object transits were reported from the Optical
Gravitational Lensing Experiment (OGLE). Our follow-up low-resolution
spectroscopy of 16 candidates provided two objects, OGLE-TR-3 and OGLE-TR-10,
which have companions with radii compatible with those of gas-giant planets.
Further high-resolution spectroscopy revealed a very low velocity variation
(<500m/s) of the host star OGLE-TR-3 which may be caused by its unseen
companion. An analysis of the radial velocity and light curve results in M<2.5
M_jup, R<1.6 R_jup, and an orbital separation of about 5 R_sol, which makes it
the planet with the shortest period known. This allows to identify the
low-luminosity companion of OGLE-TR-3 as a possible new gas-giant planet. If
confirmed, this makes OGLE-TR-3 together with OGLE-TR-56 the first extrasolar
planets detected via their transit light curves.


title: An HST/WFPC2 Snapshot Survey of 2MASS-Selected Red QSOs

abstract:
  Using simple infrared color selection, 2MASS has found a large number of red,
previously unidentified, radio-quiet QSOs. Although missed by UV/optical
surveys, the 2MASS QSOs have K-band luminosities that are comparable to
"classical" QSOs. This suggests the possible discovery of a previously
predicted large population of dust-obscured radio-quiet QSOs. We present the
results of an imaging survey of 29 2MASS QSOs observed with WFPC2 onboard the
Hubble Space Telescope. I-band images, which benefit from the relative
faintness of the nuclei at optical wavelengths, are used to characterize the
host galaxies, measure the nuclear contribution to the total observed I-band
emission, and to survey the surrounding environments. The 2MASS QSOs are found
to lie in galaxies with a variety of morphologies, luminosities, and dynamical
states, not unlike those hosting radio-quiet PG QSOs. Our analysis suggests
that the extraordinary red colors of the 2MASS QSOs are caused by extinction of
an otherwise typical QSO spectrum due to dust near the nucleus.


title:
Galaxy Populations and Evolution in Clusters IV: Deep HI Observations of
  Dwarf Ellipticals in the Virgo Cluster

abstract:
  We present in this paper the deepest Arecibo HI observations of Virgo cluster
dwarf ellipticals (dEs) taken to date. Based on this data we argue that a
significant fraction of Virgo cluster dEs recently underwent evolution. Our new
observations consist of HI 21-cm line observations for 22 classified dE
galaxies with optical radial velocities consistent with membership in the Virgo
cluster. Cluster members VCC 390 and VCC 1713 are detected with HI masses M(HI)
= 6*10^7 M_solar and 8*10^7 M_solar, respectively, while M(HI) in the remaining
20 dE galaxies have upper limits as low as 5*10^5 M_solar. We combine our
results with those for 27 other Virgo cluster dEs with HI observations in the
literature, 7 of which have HI detection claims. New optical images from the
WIYN telescope of 5 of these HI-detected dEs, along with archival data, suggest
that seven of the claimed detections are real, yielding a ~ 15% detection rate.
These HI-detected classified dEs are preferentially located near the periphery
of the Virgo cluster. Three Virgo dEs have observed HI velocity widths > 200
km/s, possibly indicating the presence of a large dark matter content, or
transient extended HI. We discuss the possible origins of these objects and
argue that they originate from field galaxies accreted onto high angular
momentum orbits by Virgo in the last few Gyr. As a result these galaxies are
slowly transformed within the cluster by gradual gas stripping processes,
associated truncation of star formation, and passive fading of stellar
populations. Low-mass early-type cluster galaxies are therefore currently being
produced as the product of cluster environmental effects. We utilize our
results to estimate the recent (past 1-3 Gyr) average mass accretion rate into
the Virgo cluster, finding dM/dt ~ 50 M_solar/year.


title: Volatile-Rich Earth-Mass Planets in the Habitable Zone

abstract:
  A small planet is not necessarily a terrestrial planet. Planets that form
beyond the snow line with too little mass to seed rapid gas accretion (<~ 10
Earth masses) should be rich in volatile ices like water and ammonia. Some of
these planets should migrate inward by interacting with a circumstellar disk or
with other planets. Such objects can retain their volatiles for billions of
years or longer at ~1 AU as their atmospheres undergo slow hydrodynamic escape.
These objects could appear in future surveys for extrasolar Earth analogs.


title: ATCA HI Observations of the NGC 6845 Galaxy Group

abstract:
  We present the results of ATCA HI line and 20-cm radio continuum observations
of the galaxy Quartet NGC 6845. The HI emission extends over all four galaxies
but can only be associated clearly with the two spiral galaxies, NGC 6845A and
B, which show signs of strong tidal interaction. We derive a total HI mass of
at least 1.8 x 10^10 Msun, most of which is associated with NGC 6845A, the
largest galaxy of the group. We investigate the tidal interaction between NGC
6845A and B by studying the kinematics of distinct HI components and their
relation to the known HII regions. No HI emission is detected from the two
lenticular galaxies, NGC 6845C and D. A previously uncatalogued dwarf galaxy,
ATCA J2001-4659, was detected 4.4' NE from NGC 6845B and has an HI mass of
about 5 x 10^8 Msun. No HI bridge is visible between the group and its newly
detected companion.
  Extended 20-cm radio continuum emission is detected in NGC 6845A and B as
well as in the tidal bridge between the two galaxies. We derive star formation
rates of 15 to 40 Msun/yr.


title:
SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. II. The
  Source Catalogue

abstract:
  This paper is the second in a series describing the Sydney University
Molonglo Sky Survey (SUMSS) being carried out at 843MHz with the Molonglo
Observatory Synthesis Telescope (MOST). The survey will consist of ~590 4.3deg.
x 4.3deg. mosaic images with 45"x45"cosec|dec.| resolution, and a source
catalogue. In this paper we describe the initial release (version 1.0) of the
source catalogue consisting of 107,765 radio sources made by fitting elliptical
gaussians in 271 SUMSS mosaics to a limiting peak brightness of 6mJy/beam at
dec.<=-50deg. and 10mJy/beam at dec.>-50deg.. The catalogue covers
approximately 3500deg^2 of the southern sky with dec.<=-30deg., about 43 per
cent of the total survey area. Positions in the catalogue are accurate to
within 1"-2" for sources with peak brightness A>=20mJy/beam and are always
better than 10". The internal flux density scale is accurate to within 3 per
cent. Image artefacts have been classified using a decision tree, which
correctly identifies and rejects spurious sources in over 96 per cent of cases.
Analysis of the catalogue shows that it is highly uniform and is complete to
8mJy at dec.<=-50^deg. and 18mJy at dec.>-50deg.. In this release of the
catalogue about 7000 sources are found in the overlap region with the NRAO VLA
Sky Survey (NVSS) at 1.4GHz. We calculate a median spectral index of
alpha=-0.83 between 1.4GHz and 843MHz. This version of the catalogue will be
released via the World Wide Web with future updates as new mosaics are
released.


title:
On the evolutionary status of chemically peculiar stars of the upper
  main sequence

abstract:
  We present further evidence that the magnetic chemically peculiar stars (CP2)
of the upper main sequence already occur at very early stages of the stellar
evolution, significantly before they reach 30% of their life-time on the main
sequence. This result is especially important for models dealing with dynamo
theories, angular momentum loss during the pre- as well as main sequence and
evolutionary calculations for CP2 stars. Results from the literature either
derived for objects in the Hyades and the UMa cluster or from the Hipparcos
mission contradict each other. A way out of this dilemma is to investigate
young open clusters with known ages and accurate distances (error < 10%),
including CP2 members. Up to now, four open clusters fulfill these
requirements: IC 2391, IC 2602, NGC 2451A and NGC 2516. In total, 13 CP2 stars
can be found within these clusters. We have used the measurements and
calibrations of the Geneva 7-color photometric system to derive effective
temperatures and luminosities. Taking into account the overall metallicity of
the individual clusters, isochrones and evolutionary tracks were used to
estimate ages and masses for the individual objects. The derived ages (between
10 and 140 Myr) are well in line with those of the corresponding clusters and
further strengthen the membership of the investigated CP2 stars.


title:
On the Mass-to-Light ratio and the Initial Mass Function in disc
  galaxies

abstract:
  A low mass-to-light ratio for the stellar component of spiral galaxies (M/L<1
in the I-band) is advocated by various dynamical arguments and by recent
cosmological simulations of the formation of these systems. We discuss this
possibility by means of chemo-photometric models for galactic discs, adopting
different Initial Mass Functions. We show that a number of "bottom--light" IMFs
(namely, with less mass locked in low-mass stars than the standard Salpeter
IMF), suggested independently in recent literature, do imply M/L ratios as low
as mentioned above, at least for late type spirals (Sbc/Sc). This conclusion
still holds when the bulge contribution to mass and light is included. We also
predict the typical stellar M/L ratio, and correspondingly the zero-point of
the Tully-Fisher relation, to vary considerably with Hubble type (about 0.5-0.7
mag in the red bands, from Sa to Sc type).
  For some of the bottom-light IMFs considered, the efficiency of metal
production tends to exceed what is typically estimated for spiral galaxies.
Suitable tuning of the IMF mass limits, post-supernova fallback of metals onto
black holes or metal outflows must then be invoked, to reproduce the observed
chemical properties of disc galaxies.
  In the appendix we provide M/L-colour relations to estimate the stellar M/L
ratio of a galaxy on the base of its colours, for several IMFs.


title:
A study of lambda Bootis type stars in the wavelength region beyond
  7000A

abstract:
  The group of lambda Bootis type stars comprises late B- to early F-type,
Population I objects which are basically metal weak, in particular the Fe group
elements, but with the clear exception of C, N, O and S. One of the theories to
explain the abundance pattern of these stars involves circumstellar or
interstellar matter around the objects. Hence, we have compiled all available
data from the literature of well established members of the lambda Bootis group
redward of 7000A in order to find evidence for matter around these objects.
Furthermore, we present unpublished ISO as well as submillimeter continuum and
CO (2-1) line measurements to complete the data set. In total, measurements for
34 (26 with data redward of 20 mu m) well established lambda Bootis stars are
available. There is evidence for an infrared excesses in six stars (HD 31295,
HD 74873, HD 110411, HD 125162, HD 198160/1 and HD 210111) and two are doubtful
cases (HD 11413 and HD 192640) resulting in a percentage of 23% (excluding the
two doubtful cases). Dust models for these objects show fractional dust
luminosities comparable to the Vega-type stars and slightly higher dust
temperatures. ISO-SWS spectroscopy for HD 125162 and HD 192640 resulted in the
detection of pure stellar HI lines ruling out an active accretion disk (as
found for several Herbig Ae/Be stars) around these objects. The submillimeter
measurements gave only upper limits for the line and continuum fluxes.


title: Stroemgren uvby photometry of the open clusters NGC 6192 and NGC 6451

abstract:
  We have investigated the two open clusters NGC 6192 and NGC 6451 for which
widely different reddening values and thus ages and distances can be found in
the literature via Stroemgren uvby photometry. Our measurements allow to
disentangle the apparent discrepancies from the literature and to derive new
accurate values. From appropriate calibrations we find that the overall
abundance for NGC 6192 is about solar whereas a subsolar value for NGC 6451 was
estimated. From two previous reported photometrically candidate CP stars, one
within NGC 6192 shows Stroemgren indices typical for a B8Si star whereas the
other object of NGC 6451 is most probably a foreground G-type star.


title: Photon yields from nitrogen gas and dry air excited by electrons

abstract:
  In order to detect ultrahigh-energy cosmic rays (UHECR), atmospheric
fluorescence light from the trajectory of the extensive air shower may be
measured by mirror-photosensor systems. In this type of experiment the photon
yield from electrons exciting air of various densities and temperatures is most
fundamental information for estimating the primary energy of UHECR. An
experiment has been undertaken using a Sr90 $\beta$ source to study the
pressure dependence of photon yields, and the life times of the excited states,
for radiation in nitrogen and dry air. The photon yield between 300 nm and 406
nm in air excited by 0.85 MeV electrons is 3.73+-0.15 (+-14% systematic)
photons per meter at 1000 hPa and 20 $^{\circ}$C. The air density and
temperature dependence is given for application to UHECR observations.


title:
Dissipation in Poynting-flux Dominated Flows: the Sigma-Problem of the
  Crab Pulsar Wind

abstract:
  Flows in which energy is transported predominantly as Poynting flux are
thought to occur in pulsars, gamma-ray bursts and relativistic jets from
compact objects. The fluctuating component of the magnetic field in such a flow
can in principle be dissipated by magnetic reconnection, and used to accelerate
the flow. We investigate how rapidly this transition can take place, by
implementing into a global MHD model, that uses a thermodynamic description of
the plasma, explicit, physically motivated prescriptions for the dissipation
rate: a lower limit on this rate is given by limiting the maximum drift speed
of the current carriers to that of light, an upper limit follows from demanding
that the dissipation zone expand only subsonically in the comoving frame and a
further prescription is obtained by assuming that the expansion speed is
limited by the growth rate of the relativistic tearing mode. In each case,
solutions are presented which give the Lorentz factor of a spherical wind
containing a transverse, oscillating magnetic field component as a function of
radius. In the case of the Crab pulsar, we find that the Poynting flux can be
dissipated before the wind reaches the inner edge of the Nebula if the pulsar
emits electron positron pairs at a rate >1.E40 per second, thus providing a
possible solution to the sigma-problem.


title:
Photon Emission in a Cascade from Relativistic Protons Initiated by
  Residual Thermal Photons in Gamma-Ray Bursts

abstract:
  Gamma-ray bursts are generally considered to be the result of internal shocks
generated in an inhomogeneous relativistic outflow that arises from a fireball.
In such shocks, the Fermi acceleration of protons is naturally expected to be
at least as efficient as that of electrons. We investigate the consequences of
proton acceleration in the residual thermal photon field of a fireball,
especially those on the emission spectra of photons. In contrast to most other
studies, we do not invoke a direct electron acceleration in shock waves. We
show that the residual radiation field of the fireball can ignite the photopion
production and subsequent cascade, and that the photons emitted in this process
further enhance the photon-initiated cascade. We find that Fermi accelerated
protons with $\gtrsim 10^{13}$ eV efficiently bring their energy into pion
production and subsequent photon emission. The particles cascading from the
pions emit photons over a wide energy range. The photons emitted from
electron--positron pairs distribute continuously from the GeV range down to the
X-ray range, while muons can emit gamma-rays by synchrotron radiation with a
break at around 1--10 MeV. We also discuss several radiation processes which
may possibly produce a break feature in the MeV range, as observed in addition
to muon synchrotron radiation.


title:
Comments on ``The first detections of the Extragalactic Background Light
  at 3000, 5500, and 8000 A'' by Bernstein, Freedman and Madore

abstract:
  A critical discussion is presented of the data analysis applied by Bernstein,
Freedman and Madore (2002 ApJ, 571, 56; and ApJ 571, 85) in their measurement
of the Extragalactic Background Light. There are questionable assumptions in
the analysis of the ground-based observations of the Zodiacal Light. The
modeling of the Diffuse Galactic Light is based on an underestimated value of
the dust column density along the line of sight. Comparison with the previously
presented results from the same observations reveals a puzzling situation: in
spite of a large difference in the atmospheric scattered light corrections the
derived Extragalactic Background Light values are exactly the same. The claim
of the paper of a ``detection of the Extragalactic Background Light'' appears
premature.


title: WIYN Open Cluster Study: Tidal Interactions in Solar type Binaries

abstract:
  We present an ongoing study on tidal interactions in late-type close binary
stars. New results on tidal circularization are combined with existing data to
test and constrain theoretical predictions of tidal circularization in the
pre-main-sequence (PMS) phase and throughout the main-sequence phase of stellar
evolution. Current data suggest that tidal circularization during the PMS phase
sets the tidal cutoff period for binary populations younger than ~1 Gyr. Binary
populations older than ~1 Gyr show increasing tidal cutoff periods with age,
consistent with active main-sequence tidal circularization.


title:
Numerical constraints on the model of stochastic excitation of
  solar-type oscillations

abstract:
  Analyses of a 3D simulation of the upper layers of a solar convective
envelope provide constraints on the physical quantities which enter the
theoretical formulation of a stochastic excitation model of solar p modes, for
instance the convective velocities and the turbulent kinetic energy spectrum.
These constraints are then used to compute the acoustic excitation rate for
solar p modes, P. The resulting values are found ~5 times larger than the
values resulting from a computation in which convective velocities and entropy
fluctuations are obtained with a 1D solar envelope model built with the
time-dependent, nonlocal Gough (1977) extension of the mixing length
formulation for convection (GMLT). This difference is mainly due to the assumed
mean anisotropy properties of the velocity field in the excitation region. The
3D simulation suggests much larger horizontal velocities compared to vertical
ones than in the 1D GMLT solar model. The values of P obtained with the 3D
simulation constraints however are still too small compared with the values
inferred from solar observations. Improvements in the description of the
turbulent kinetic energy spectrum and its depth dependence yield further
increased theoretical values of P which bring them closer to the observations.
It is also found that the source of excitation arising from the advection of
the turbulent fluctuations of entropy by the turbulent movements contributes ~
65-75 % to the excitation and therefore remains dominant over the Reynolds
stress contribution. The derived theoretical values of P obtained with the 3D
simulation constraints remain smaller by a factor ~3 compared with the solar
observations. This shows that the stochastic excitation model still needs to be
improved.


title: The Rotation of Low-Mass Pre-Main-Sequence Stars

abstract:
  Major photometric monitoring campaigns of star-forming regions in the past
decade have provided rich rotation period distributions of pre-main-sequence
stars. The rotation periods span more than an order of magnitude in period,
with most falling between 1 and 10 days. Thus the broad rotation period
distributions found in 100 Myr clusters are already established by an age of 1
Myr. The most rapidly rotating stars are within a factor of 2-3 of their
critical velocities; if angular momentum is conserved as they evolve to the
ZAMS, these stars may come to exceed their critical velocities. Extensive
efforts have been made to find connections between stellar rotation and the
presence of protostellar disks; at best only a weak correlation has been found
in the largest samples. Magnetic disk-locking is a theoretically attractive
mechanism for angular momentum evolution of young stars, but the links between
theoretical predictions and observational evidence remain ambiguous. Detailed
observational and theoretical studies of the magnetospheric environments will
provide better insight into the processes of pre-main-sequence stellar angular
momentum evolution.


title: A rigorous comparison of different planet detection algorithms

abstract:
  The idea of finding extrasolar planets (ESPs) through observations of drops
in stellar brightness due to transiting objects has been around for decades. It
has only been in the last ten years, however, that any serious attempts to find
ESPs became practical. The discovery of a transiting planet around the star HD
209458 (Charbonneau et al. 2000) has led to a veritable explosion of research,
because the photometric method is the only way to search a large number of
stars for ESPs simultaneously with current technology. To this point, however,
there has been limited research into the various techniques used to extract the
subtle transit signals from noise, mainly brief summaries in various papers
focused on publishing transit-like signatures in observations. The scheduled
launches over the next few years of satellites whose primary or secondary
science missions will be ESP discovery motivates a review and a comparative
study of the various algorithms used to perform the transit identification, to
determine rigorously and fairly which one is the most sensitive under which
circumstances, to maximize the results of past, current, and future
observational campaigns.


title:
Annual modulation in the scattering of J1819+3845: peculiar plasma
  velocity and anisotropy

abstract:
  We present two years of monitoring observations of the extremely variable
quasar J1819+3845. We observe large yearly changes in the timescale of the
variations (from ~ 1 hour to ~ 10 hours at 5GHz). This annual effect can only
be explained if the variations are caused by a propagation effect, and thus
affected by the Earth's relative speed through the projected intensity pattern.
To account for this effect, the scattering plasma must have a transverse
velocity with respect to the local standard of rest.
  The velocity calculated from these observations is in good agreement with
that obtained from a two telescope delay experiment (Dennett-Thorpe & de Bruyn
2001). We also show that either the source itself is elongated, or that the
scattering plasma is anisotropic, with an axial ratio of >6:1. As the source is
extended on scales relevant to the scattering phenomenon, it seems plausible
that the anisotropy is due to the source itself, but this remains to be
investigated. From the scintillation characteristics we find that the
scattering material is a very strong, thin scatterer within ~ten parsecs. We
determine a source size at 5GHz of 100 to 900microarcsecs, and associated
brightness temperatures of 10^{10} to 10^{12}K.


title: Monte Carlo transition probabilities. II

abstract:
  The macroscopic quantizations of matter into macro-atoms and radiant and
thermal energies into r- and k-energy packets initiated in Paper I is completed
with the definition of transition probabilities governing energy flows to and
from the thermal pool. The resulting Monte Carlo method is then applied to the
problem of computing the hydrogen spectrum of a Type II supernova. This test
problem is used to demonstrate the scheme's consistency as the number of energy
packets N -> infinity, to investigate the accuracy of Monte Carlo estimators of
radiative rates, and to illustrate the convergence characteristics of the
geometry-independent, constrained Lambda-iteration method employed to obtain
the NLTE stratifications of temperature and level populations. In addition, the
method's potential, when combined with analytic ionization and excitation
formulae, for obtaining useful approximate NLTE solutions is emphasized.


title:
The Star Formation Histories of Four Fields Spanning the Minor Axis of
  NGC 6822

abstract:
  The star formation histories of four fields within the Local Group dwarf
irregular galaxy NGC 6822 are presented. Each of the fields was imaged by the
WFPC2 aboard the {\it Hubble Space Telescope} and were used to obtain $VI$
color-magnitude diagrams for each field reaching $V\simeq26$. The magnitude of
the tip of the red giant branch and the red clump were used to determine
distances to NGC 6822 that are consistent with previous ground-based
measurements. The distance, extinction and star formation history were also
determined by fitting the entire color-magnitude diagram in each field. The
distances from these fits are consistent with the other determinations within
the estimated errors once the systematic effects of uncertainties in the
age-metallicity relation are taken into account. The extinction varies among
the four fields from approximately the foreground Galactic value to $\approx
0.4$ mag higher in $V$ and roughly correlates with the $60\micron$ surface
brightness. The star formation histories in the four fields are similar for
ages $\gtrsim 1$ Gyr and are relatively constant or somewhat increasing with
time. These old star formation rates are comparable to that expected from the
typical gas surface densities at these galactocentric radii and suggest that no
large scale redistribution of gas or stars is required to account for the
inferred star formation rates. Three of the fields show a drop of a factor of
$\sim 2-4$ in the star formation rate about 600 Myr ago while the remaining
field centered on the bar shows an increase.


title: Neutrino transport in accretion disks

abstract:
  We test approximate approaches to solving a neutrino transport problem that
presents itself in the analysis of some accretion-disk models. Approximation #1
consists of replacing the full, angular- dependent, distribution function by a
two-stream simulation, where the streams are respectively outwardly and
inwardly directed, with angles $\cos \theta=\pm 1/\sqrt{3}$ to the vertical. In
this approximation the full energy dependence of the distribution function is
retained, as are the energy and temperature dependences of the scattering
rates. Approximation #2, used in recent works on the subject, replaces the
distribution function by an intensity function and the scattering rates by
temperature-energy-averaged quantities. We compare the approximations to the
results of solving the full Boltzmann equation. Under some interesting
conditions, approximation #1 passes the test; approximation #2 does not. We
utilize the results of our analysis to construct a toy model of a disc at a
temperature and density such that relativistic particles are more abundant than
nucleons, and dominate both the opacity and pressure. The nucleons will still
provide most of the energy density. In the toy model we take the rate of heat
generation (which drives the radiative transfer problem) to be proportional to
the nucleon density. The model allows the simultaneous solution of the neutrino
transport and hydrostatic equilibrium problems in a disk in which the nucleon
density decreases approximately linearly as one moves from the median plane of
the disk upwards, reaching zero on the upper boundary.


title: Portent of Heine's Reciprocal Square Root Identity

abstract:
  Precise efforts in theoretical astrophysics are needed to fully understand
the mechanisms that govern the structure, stability, dynamics, formation, and
evolution of differentially rotating stars. Direct computation of the physical
attributes of a star can be facilitated by the use of highly compact azimuthal
and separation angle Fourier formulations of the Green's functions for the
linear partial differential equations of mathematical physics.


title:
The Nature, Evolution, Clustering and X-ray Properties of Extremely Red
  Galaxies in the CDFS/GOODS field

abstract:
  We identify a deep sample of 198 extremely red objects (EROs) in (50.4 sq.
arcmin of) the Chandra Deep Field South, selected as I-K>3.92 galaxies to a
limit K=22. The ERO number counts remain well below the predictions for pure
luminosity evolution, and fall below even a non-evolving model, suggesting the
comoving number density of passive/very red galaxies decreases with redshift.
The angular correlation function of these EROs indicates stronger clustering
than that of other galaxies at the same magnitudes, and is best-fitted by
models in which the EROs have a comoving correlation radius 12.5/h Mpc, or
21.4/h Mpc in a stable clustering model. We find a 40-arcsec diameter grouping
of 10 EROs, centered on the Chandra source (and ERO) XID:58, with colours
suggesting a cluster of mostly passive EROs at approx. z=1.5. The 942 ksec
Chandra survey detected 73 X-ray sources in the area of our ERO sample, of
which 17 coincide with EROs. Of these sources, 13 have X-ray properties
indicative of obscured AGN, while the faintest 4 may be starburst galaxies. In
addition, we find evidence that Chandra sources and EROs are positively
cross-correlated at non-zero (2-20 arcsec) separations, implying that they tend
to trace the same large-scale structures.


title: Anisotropy in the angular distribution of the long gamma-ray bursts?

abstract:
  The gamma-ray bursts detected by the BATSE instrument may be separated into
"short", "intermediate" and "long" subgroups. Previous statistical tests found
an anisotropic sky-distribution on large angular scales for the intermediate
subgroup, and probably also for the short subgroup. In this article the
description and the results of a further statistical test - namely the nearest
neighbour analysis - are given. Surprisingly, this test gives an anisotropy for
the long subgroup on small angular scales. The discussion of this result
suggests that this anisotropy may be real.


title: Supernova Enrichment of Dwarf Spheroidal Galaxies

abstract:
  (Abridged) Many dwarf galaxies exhibit sub-Solar metallicities, with some
star-to-star variation, despite often containing multiple generations of stars.
The total metal content in these systems is much less than expected from the
heavy element production of massive stars in each episode of star formation.
Such a deficiency implies that a substantial fraction of the enriched material
has been lost from these small galaxies. Mass ejection from dwarf galaxies may
have important consequences for the evolution of the intergalactic medium and
for the evolution of massive galaxies, which themselves may have formed via the
merger of smaller systems. We report here the results of three-dimensional
simulations of the evolution of supernova-enriched gas within dwarf spheroidal
galaxies (dSph's), with the aim of determining the retention efficiency of
supernova ejecta. We consider two galaxy models, selected to represent opposite
ends of the dSph sequence. For each model galaxy we investigate a number of
scenarios, ranging from a single supernova in smooth gas distributions to more
complex multiple supernovae in highly disturbed gas distributions. The results
of these investigations suggest that, for low star-formation efficiencies, it
is difficult to completely expel the enriched material from the galaxy. Most of
the enriched gas is, however, lost from the core of the galaxy following
multiple supernovae, especially if the interstellar medium is already highly
disturbed by processes such as photo-ionization and stellar winds. If
subsequent star formation occurs predominantly within the core where most of
the residual gas is concentrated, then these results could explain the poor
self-enrichment efficiency observed in dwarf galaxies.


title: COSMOS: A Radiation-Chemo-Hydrodynamics Code for Astrophysical Problems

abstract:
  We have developed a new massively-parallel radiation-hydrodynamics code
(Cosmos) for Newtonian and relativistic astrophysical problems that also
includes radiative cooling, self-gravity, and non-equilibrium, multi-species
chemistry. Several numerical methods are implemented for the hydrodynamics,
including options for both internal and total energy conserving schemes.
Radiation is treated using flux-limited diffusion. The chemistry incorporates
27 reactions, including both collisional and radiative processes for atomic
hydrogen and helium gases, and molecular hydrogen chains. In this paper we
discuss the equations and present results from test problems carried out to
verify the robustness and accuracy of our code in the Newtonian regime. An
earlier paper presented tests of the relativistic capabilities of Cosmos.


title: The Radial Velocity Precision of Fiber-fed Spectrographs

abstract:
  We have measured the radial velocities of five 51 Peg-type stars and one star
with constant velocity. Our measurements, on 20 \AA centered at 3947 \AA, were
conventional using Th/Ar comparison spectra taken every 20 or 40 minutes
between the stellar exposures. Existing IRAF routines were used for the
reduction. We find $\sigma_{RV}$ $\leq$ 20 m s$^{-1}$, provided 4 measurements
(out of 72) with residuals $>5\sigma_{RV}$ are neglected. The observations were
made with the CFHT Gecko spectrograph, fiber-fed with the CAFE system
(R$\sim$110,000). $\sigma_{RV}$ $\leq$10 m s$^{-1}$ seems possible with
additional care. This study was incidental to the main program and so not
exhaustive but the small value of $\sigma_{RV}$ implies that the fiber
feed/image slicer system on Gecko + CAFE, essentially eliminates the long
standing problem of guiding errors in radial velocity measurements. We are not
suggesting this conventional approach for serious Doppler planet searches
(especially with Gecko which has such a small multiplex gain), but the
precision is valuable for observations made in spectral regions remote from
telluric lines or captive-gas fiducials. Instrument builders might consider the
advantages of the CAFE optics which incorporate agitation and invert the object
and pupil for slit and grating illumination in future spectrograph designs.


title:
Model-Independent Reconstruction of the Primordial Power Spectrum from
  WMAP Data

abstract:
  Reconstructing the shape of the primordial power spectrum in a model
independent way from cosmological data is a useful consistency check on what is
usually assumed regarding early universe physics. It is also our primary window
to unknown physics during the inflationary era. Using a power-law form for the
primordial power spectrum $P_{in}(k)$ and constraining the scalar spectral
index and its running, \cite{Peiris03} found that the first year WMAP data seem
to indicate a preferred scale in $P_{in}(k)$. We use two complementary methods:
the wavelet band powers method of \cite{pia1}, and the top-hat binning method
of \cite{Wang99} to reconstruct $P_{in}(k)$ as a free function from CMB data
alone (WMAP, CBI, and ACBAR), or from CMB data together with large scale
structure data (2dFGRS and PCSZ). The shape of the reconstructed $P_{in}(k)$ is
consistent with scale-invariance, although it allows some indication of a
preferred scale at $k \sim 0.01$Mpc$^{-1}$. While consistent with the possible
evidence for a running of the scalar spectral index found by the WMAP team, our
results highlight the need of more stringent and independent constraints on
cosmological parameters (the Hubble constant in particular) in order to more
definitively constrain deviations of $P_{in}(k)$ from scale-invariance without
making assumptions about the inflationary model.


title:
Periodic Flux Variability of Stars due to the Reflex Doppler Effect
  Induced by Planetary Companions

abstract:
  Upcoming space-based photometric satellites offer the possibility of
detecting continuum flux variability at the micro-magnitude level. We show that
the Doppler flux variability induced by the reflex motion of stars due to
planetary companions has an amplitude of (3-alpha)K/c, where K is the reflex
radial velocity amplitude and alpha is the logarithmic slope of source spectral
flux in the observed frequency band. For many of the known close-in planetary
systems with periods less than ~0.2 years, the periodic Doppler variability is
of order a micromagnitude, and is significant relative to the variability
caused by reflected light from the planetary companion. For companions with
periods greater than ~0.2 years, the Doppler signal is larger than the
reflected light signal. We show that the future photometric satellites should
reach the sensitivity to detect this Doppler variability. In particular, the
Kepler satellite should have the photon-noise sensitivity to detect at a
signal-to-noise ratio > 5, all planets with minimum mass greater than 5 Jupiter
masses, and periods less than 0.1 years around the 10,000 main-sequence stars
with spectral types A through K and apparent magnitude V<12 in its
field-of-view.


title: Magnetic collapse of a neutron gas: Can magnetars indeed be formed

abstract:
  A relativistic degenerate neutron gas in equilibrium with a background of
electrons and protons in a magnetic field exerts its pressure anisotropically,
having a smaller value perpendicular than along the magnetic field. For
critical fields the magnetic pressure may produce the vanishing of the
equatorial pressure of the neutron gas. Taking it as a model for neutron stars,
the outcome could be a transverse collapse of the star. This fixes a limit to
the fields to be observable in stable neutron star pulsars as a function of
their density. The final structure left over after the implosion might be a
mixed phase of nucleons and meson condensate, a strange star, or a highly
distorted black hole or black "cigar", but no any magnetar, if viewed as a
super strongly magnetized neutron star. However, we do not exclude the
possibility of a supersotrong magnetic fields arising in supernova explosions
which lead directly to strange stars. In other words, if any magnetars exist,
they cannot be neutron stars.


title:
Thermal conduction and particle transport in strong MHD turbulence, with
  application to galaxy-cluster plasmas

abstract:
  We investigate field-line separation in strong MHD turbulence analytically
and with direct numerical simulations. We find that in the
static-magnetic-field approximation the thermal conductivity in galaxy clusters
is reduced by a factor of about 5-10 relative to the Spitzer thermal
conductivity of a non-magnetized plasma. We also estimate how the thermal
conductivity would be affected by efficient turbulent resistivity.


title: Near-Infrared Synchrotron Emission from Cas A

abstract:
  High energy observations of Cas A suggested the presence of synchrotron
radiation, implying acceleration of cosmic rays by young supernova remnants. We
detect synchrotron emission from Cas A in the near-infrared using Two Micron
All Sky Survey (2MASS) and Palomar 200 inch PFIRCAM observations. The remnant
is detected in J, H, and Ks bands, with Ks band brightest and J faint. In the J
and H bands, bright [Fe II] lines (1.24um and 1.64um) are detected
spectroscopically. The Palomar observations include Ks continuum, narrow-band
1.64um (centered on [Fe II]) and 2.12um (centered on H2(1-0)) images. While the
narrow-band 1.64um image shows filamentary and knotty structures, similar to
the optical image, the Ks image shows a relatively smooth, diffuse shell,
remarkably similar to the radio image. The broad-band near-infrared fluxes of
Cas A are generally consistent with, but a few tens of percent higher than, an
extrapolation of the radio fluxes. The hardening to higher frequencies is
possibly due to nonlinear shock acceleration and/or spectral index variation
across the remnant. We show evidence of spectral index variation. The presence
of near-infrared synchrotron radiation requires the roll-off frequency to be
higher than 1.5e14 Hz, implying that electrons are accelerated to energies of
at least 0.2 TeV. The morphological similarity in diffuse emission between the
radio and Ks band images implies that synchrotron losses are not dominant. Our
observations show unambiguous evidence that the near-infrared Ks band emission
of Cas A is from synchrotron emission by accelerated cosmic-ray electrons.


title: The Compact Nucleus of the Deep Silicate Absorption Galaxy NGC 4418

abstract:
  High resolution, Hubble Space Telescope (HST) near-infrared and Keck
mid-infrared images of the heavily extinguished, infrared luminous galaxy NGC
4418 are presented. These data make it possible to observe the imbedded
near-infrared structure on scales of 10-20 pc, and to constrain the size of the
mid-infrared emitting region. The 1.1-2.2 um data of NGC 4418 show no clear
evidence of nuclear star clusters or of a reddened active galactic nucleus.
Instead, the nucleus of the galaxy consists of a ~100-200 pc linear structure
with fainter structures extending radially outward. The near-infrared colors of
the linear feature are consistent with a 10-300 Myr starburst suffering
moderate levels (few magnitudes) of visual extinction. At 7.9-24.5 um, NGC 4418
has estimated size upper limits in the range of 30-80 pc. These dimensions are
consistent with the highest resolution radio observations obtained to date of
NGC 4418, as well as the size of 50-70 pc expected for a blackbody with a
temperature derived from the 25 um, 60 um, and 100 um flux densities of the
galaxy. Further, a spectral energy distribution constructed from the
multi-wavelength mid-infrared observations show the strong silicate absorption
feature at 10 um, consistent with previous mid-infrared observations of NGC
4418. An infrared surface brightness of 2.1x10^13 L_sun kpc^-2 is derived for
NGC 4418. Such a value, though consistent with the surface brightness of warm
ultraluminous infrared galaxies (ULIGs: L_IR [8-1000 um] >~ 10^12 L_sun) such
as IRAS 05189-2524 and IRAS 08572+3915, is not large enough to distinguish NGC
4418 as a galaxy powered by an Active Galactic Nucleus (AGN), as opposed to a
lower surface brightness starburst.


title:
The divergence of neighboring magnetic field lines and fast-particle
  diffusion in strong magnetohydrodynamic turbulence, with application to
  thermal conduction in galaxy clusters

abstract:
  We investigate field-line separation in strong MHD turbulence using direct
numerical simulations. We find that in the static-magnetic-field approximation
the thermal conductivity in galaxy clusters is reduced by a factor of about 50
relative to the Spitzer thermal conductivity of a non-magnetized plasma. This
value is too small for heat conduction to balance radiative cooling in
clusters.


title:
Limits on diffuse fluxes of high energy extraterrestrial neutrinos with
  the AMANDA-B10 detector

abstract:
  Data from the AMANDA-B10 detector taken during the austral winter of 1997
have been searched for a diffuse flux of high energy extraterrestrial
muon-neutrinos, as predicted from, e.g., the sum of all active galaxies in the
universe. This search yielded no excess events above those expected from the
background atmospheric neutrinos, leading to upper limits on the
extraterrestrial neutrino flux. For an assumed E^-2 spectrum, a 90% classical
confidence level upper limit has been placed at a level E^2 Phi(E) = 8.4 x
10^-7 GeV cm^-2 s^-1 sr^-1 (for a predominant neutrino energy range 6-1000 TeV)
which is the most restrictive bound placed by any neutrino detector. When
specific predicted spectral forms are considered, it is found that some are
excluded.


title:
Migration of Jupiter-family comets and resonant asteroids to near-Earth
  space

abstract:
  We estimated the rate of comet and asteroid collisions with the terrestrial
planets by calculating the orbits of 13000 Jupiter-crossing objects (JCOs) and
1300 resonant asteroids and computing the probabilities of collisions based on
random-phase approximations and the orbital elements sampled with a 500 yr
step. The Bulirsh-Stoer and a symplectic orbit integrator gave similar results
for orbital evolution, but sometimes give different collision probabilities
with the Sun. A small fraction of former JCOs reached orbits with aphelia
inside Jupiter's orbit, and some reached Apollo orbits with semi-major axes
less than 2 AU, Aten orbits, and inner-Earth orbits (with aphelia less than
0.983 AU) and remained there for millions of years. Though less than 0.1% of
the total, these objects were responsible for most of the collision probability
of former JCOs with Earth and Venus. Some Jupiter-family comets can reach
inclinations i>90 deg. We conclude that a significant fraction of near-Earth
objects could be extinct comets that came from the trans-Neptunian region.


title: A Model for Quasi-Spherical Magnetized Accretion Flow

abstract:
  A model for axisymmetric magnetized accretion flow is proposed. The dominant
mechanism of energy dissipation is assumed to be the magnetic diffusivity due
to turbulence in the accretion flow. In analogy to the advection-dominated
accretion flow (ADAF) solutions, a constant fraction of the resistively
dissipated energy is stored in the accreting gas and the rest is radiated. The
general self-similar solutions which describe a resistive and {\it nonrotating}
flow with purely poloidal magnetic field is first introduced. The radial
dependence of physical quantities is identical to viscous ADAF solutions.
Although the main focus of this study is nonrotating magnetized accretion flow,
for rotating flow with both poloidal and toroidal components of magnetic field
we find the radial scaling of solutions similar to the nonrotating case. We
show that the accretion and the rotation velocities are both below the
Keplerian rate, irrespective of the amount of cooling. We show that the set of
the equations is reduced to a second order differential equation for a
nonrotating flow. The geometrical shape of the disk changes depending on the
fraction of the resistively dissipated energy which is stored in the accreting
gas. However, there is a hot low-density gas above the disk in almost all
cases. The net accretion rate is calculated for a set of illustrative
parameters.


title:
Searching for Planets in the Hyades IV: Differential Abundance Analysis
  of Hyades Dwarfs

abstract:
  We present a differential abundance analysis of Hyades F-K dwarfs in search
for evidence of stellar enrichment from accreted hydrogen deficient disk
material. Metallicites and relative abundance ratios of several species have
been determined. We derive a cluster mean [Fe/H] = 0.13+-0.01. Two stars show
abundances ~0.2 dex larger than the cluster mean. Additionally, one star, which
was added by a recent study as a cluster member, shows significantly lower
abundances than the cluster mean. These three stars have questionable
membership characteristics. The remaining stars in the survey have an rms of
0.04 dex in the differential [Fe/H] values. The Hyades cluster members have
apparently not been significantly chemically enriched. The abundance ratios of
Si, Ti, Na, Mg, Ca and Zn with respect to Fe are in their solar proportions.


title: Galactic Halos in MONDian Cosmological Simulations

abstract:
  In this paper a series of high-resolution n-body simulations is presented in
which the equations of motion have been changed to account for MOdified
Newtonian Dynamics (MOND). It is shown that a low-Omega0 MONDian model with an
appropriate choice for the normalisation sigma8 can lead to similar clustering
properties at redshift z=0 as the commonly accepted (standard) LCDM model.
However, such a model shows no significant structures at high redshift with
only very few objects present beyond z>3 that can be readily ascribed to the
low Omega0 value adopted. The agreement with LCDM at redshift z=0 is driven by
the more rapid structure evolution in MOND. Moreover, galaxy formation appears
to be more strongly biased in MONDian cosmologies. Within the current
implementation of MOND density profiles of gravitationally bound objects at z=0
can still be fitted by the universal NFW profile but MOND halos are less
clumpy.


title:
Infrared spectroscopy of faint 15 micron sources in the Hubble Deep
  Field South: first hints at the properties of the sources of the IR
  background

abstract:
  We present a spectroscopic analysis of 21 galaxies with z=0.2-1.5 drawn from
a 25 sq. arcmin ultra-deep 15 micron ISOCAM survey centered in the HDFS.
VLT/ISAAC spectra are reported for 18 sources, aimed at detecting the
redshifted Ha. Optical data come from VLT/FORS2 and NTT/EMMI. Ha line emission
is detected in all the observed objects. Our analysis of emission lines,
morphology, and SEDs shows evidence for AGN in only two of these sources. The
Ha luminosities indicate star formation rates (SFR) between 0.5 and 20 Msun,
without extinction corrections. We find good correlations between the mid-IR,
the radio and Ha luminosities, confirming the mid-IR light as a good tracer of
star formation (while SFR based on Ha flux show large scatter and offset, still
to be understood). We have estimated the baryonic masses in stars by fitting
the optical-IR SED, and found that the host galaxies of ISO sources are massive
members of groups with SFR=10 to 300 Msun/yr. We have finally compared this
ongoing SF activity with the already formed stellar masses to estimate the
timescales t(SF) for the stellar build-up, which turn-out to be widely spread
between 0.1 Gyrs to more than 10 Gyr. The faint ISOCAM galaxies appear to form
a composite population, including moderately active but very massive
spiral-like galaxies, and very luminous ongoing starbursts, in a continuous
sequence. From the observed t(SF), assuming typical starburst timescales, we
infer that, with few exceptions, only a fraction of the galactic stars can be
formed in any single starburst, while several of such episodes during a
protracted SF history are required for the whole galactic build-up.


title: Period change of Superhumps in the WZ Sge-Type Dwarf Nova, HV Virginis

abstract:
  After 10 years of quiescence, HV Vir underwent a superoutburst in January
2002. We report time-series observations clearly revealing the period change of
ordinary superhumps during the superoutburst. We derived a mean superhump
period of 0.058260 d and a positive period derivative of $7 \times 10^{-5}$.
These results are in good agreement with the value obtained from the 1992
superoutburst. We also detected early superhumps, which were not clearly
recognized in the past outburst, and a possible rebrightening. Both of them are
the common characteristics of WZ Sge-type stars.


title:
The 5200A flux depression of chemically peculiar stars: I. Synthetic
  Delta a photometry - the normality line

abstract:
  The Delta a photometric system provides an efficient observational method to
identify and distinguish magnetic and several other types of chemically
peculiar (CP) stars of spectral types B to F from other classes of stars in the
same range of effective temperatures. We have developed a synthetic photometric
system which can be used to explore the capability of model atmospheres with
individual element abundances to predict photometric Delta a magnitudes which
measure the extent of the flux depression around 5200A found in different types
of CP stars. In this first paper, we confirm the observed dependency of the
a-index as a function of various colour indices sensitive to the effective
temperature of stars as well as its average scatter expected from surface
gravity variations within the main sequence band. The behaviour of the
so-called normality line of Delta a systems used in photometric observations of
CP stars is well reproduced. The metallicity dependence of the normality line
of the Delta a system was computed for several grids of model atmospheres where
the abundances of elements heavier than He had been scaled +-0.5 dex with
respect to the solar value. We estimate a lowering of Delta a magnitudes for CP
stars within the Magellanic Clouds by approximately -3 mmag relative to those
in the solar neighbourhood assuming an average metallicity of [Fe/H]= -0.5 dex.
Using these results on the metallicity bias of the Delta a system we find the
observational systems in use suitable to identify CP stars in other galaxies or
distant regions of our own galaxy and capable to provide data samples on a
statistically meaningful basis. In turn, the synthetic system is suitable to
test the performance of model atmospheres for CP stars. This work will be
presented in follow-up papers of this series.


title: Supernova neutrinos: Flavor-dependent fluxes and spectra

abstract:
  Transporting nu_mu and nu_tau in a supernova (SN) core involves several
processes that have been neglected in traditional simulations. Based on a Monte
Carlo study we find that the flavor-dependent spectral differences are much
smaller than is often stated in the literature. A full-scale SN simulation
using a Boltzmann solver and including all relevant neutrino reactions confirms
these results. The flavor-dependent flux differences are largest during the
initial accretion phase.


title:
Galactic distribution of merging neutron stars and black holes -
  prospects for short GRB progenitors and LIGO/VIRGO

abstract:
  We have performed detailed population synthesis on a large number (20
million) of binary systems in order to investigate the properties of massive
double degenerate binaries. We have included new important results in our input
physics in order to obtain more reliable estimates of the merging timescales
and relative formation rates. These improvements include refined treatment of
the binding energy in a common envelope, helium star evolution and reduced
kicks imparted to newborn black holes. The discovery and observations of GRB
afterglows and the identification of host galaxies have allowed comparisons of
theoretical distributions of merger sites with the observed distribution of
afterglow positions relative to host galaxies. To help investigate the physical
nature of short- and long-duration GRBs, we compute the distances of merging
neutron stars (NS) and/or black holes (BH) from the centers of their host
galaxies, as predicted by their formation scenario combined with motion in
galactic potentials. Furthermore, we estimate the formation rate and merging
rate of these massive double degenerate binaries. The latter is very important
for the prospects of detecting gravitational waves with LIGO/VIRGO. We find
that the expected detection rate for LIGO II is ~850 per year for galactic
field sources and that this rate is completely dominated by merging BHBH
binaries. Even LIGO I may detect such an event (~0.25 per year). Our preferred
model estimate the Galactic field NSNS merger rate to be ~1.5*10^(-6) per year.
For BHBH systems this model predicts a merger rate of ~9.7*10^{-6} per year.
Our studies also reveal an accumulating numerous population of very wide orbit
BHBH systems which never merge (t >> t_Hubble).


title: Tracking and coupled dark energy as seen by WMAP

abstract:
  The satellite experiment WMAP has produced for the first time a
high-coverage, high resolution survey of the microwave sky, releasing publicly
available data that are likely to remain unrivalled for years to come. Here we
compare the WMAP temperature power spectrum, along with an exhautive
compilation of previous experiments, to models of dark energy that allow for a
tracking epoch at the present, deriving updated bounds on the dark energy
equation of state and the other cosmological parameters. Moreover, we
complement the analysis by including a coupling of the dark energy to dark
matter. The main results are: a) the WMAP data alone constrains the equation of
state of tracking dark energy to be w_\phi<-0.67(-0.49) to 68%(95%) (confining
the analysis to w_\phi>-1), which implies for an inverse power law potential an
exponent \alpha<0.99(2.08); b) the dimensionless coupling to dark matter is
|\beta|<0.07(0.13). Including the results from the supernovae Ia further
constrains the dark energy equation of state.


title:
Dynamics of the Globular Cluster System Associated with M49 (NGC4472):
  Cluster Orbital Properties and the Distribution of Dark Matter

abstract:
  We have measured radial velocities for 196 globular clusters (GCs) around
M49, the brightest member of the Virgo Cluster. Combined with published data,
they bring the total number of GCs with measured radial velocities in this
galaxy to 263. Using this sample, we extract the projected kinematics of the
full sample of GCs, and of the separate metal-poor and metal-rich subsamples.
In agreement with previous results for the global GC kinematics based on
smaller datasets, we find that the GC system as a whole exhibits a slow overall
rotation that is due almost entirely to a net rotation of the metal-poor GC
subsystem alone. In a spatial average, the metal-rich GCs shows essentially no
rotation. We note, however, the presence of a well defined grouping of 10
metal-rich GCs that are located at opposite poles along the galaxy's major axis
and which appear to be rotating at nearly 300 km/s about the minor axis. This
grouping may be the relic of a past merger or accretion event. Using a
Jeans-equation analysis, we show that the GC radial velocities alone point
unequivocally (and independently of X-ray observations) to the need for a
massive dark halo associated with M49 and the Virgo B subcluster around it. We
also show that the GC system as a whole is consistent with an almost perfectly
isotropic velocity ellipsoid. M49 is now the second elliptical galaxy (after
M87) for which we have been able to demonstrate velocity isotropy in the
globular cluster system overall, when no division based on GC color or
metallicity is attempted. Thus, the data for these two galaxies lend support
the general assumption of isotropy when using GC kinematics to study the
dark-matter distribution in early-type galaxies. (ABRIDGED)


title: HST astrometry: the Galactic constant Theta_0/R_0

abstract:
  From multi-epoch WFPC2/HST observations we present astrometric measurements
of the absolute motion of the bulge stars. The presence of an extragalactic
point-source candidate allows us to measure the difference between the Oort
constants, A-B = Theta_0/R_0. We find: Theta_0/R_0 = 27.4 +/- 1.8 km/s/kpc.


title: A Joint model for radio and gamma-ray emission from pulsars

abstract:
  Although pulsars can radiate electromagnetic wave from radio to gamma ray
bands, we still have no a united model to understand the multi-band emission.
In this paper the effort for a joint model is presented. The inverse Compton
scattering (ICS) and a second acceleration process near the null charge surface
are involved to account for the radio and the gama-ray emission, respectively.
Various kind of pulse profiles and other observational properties can be
reproduced.


title: Radio and gamma-ray emission from pulsars

abstract:
  The radiation of pulsars have been observed for many years. A few pulsars are
discovered to have both radio and gamma-ray emission. Many models on pulsar
radiation have been developed, but so far we are still lacking an elaborate
model which can explain the emission from radio to gamma-rays in detail. In
this paper we present a joint model for radio and gamma-ray emission, in which
both the dominate emission mechanisms are inverse Compton scattering. The pulse
profiles at radio and gamma-ray bands are reproduced for the Crab-like,
Vela-like and Geminga-like pulsars, in good agreement with observations.


title: Ultra High Energy Particle Astronomy, Neutrino Masses and Tau Airshowers

abstract:
  Ultra High Energy (UHE) neutrino Astronomy and relic Neutrino masses may play
a key role in solving the Ultra High Energy Cosmic Ray (UHECR) puzzle within
the Z-Showering model. Tau air-shower originated by UHE neutrino in matter may
probe and amplify this expected UHE neutrino Astronomy. The discover of
upcoming and horizontal tau air-showers (UPTAUs, HORTAUs), born by UHE, nu_tau
interacting inside mount chains or along Earth Crust crown masses at the
Horizons edges, will greatly amplify the single UHE nu_tau track. Observing
UPTAUs and HORTAUs along their line of showering, from higher balloons or
satellites, at Greisen-Zatsepin-Kuzmin (GZK) energies above 10^19 eV, may test
a calorimeter mass exceeding 150 km^3 (water equivalent). Observing Horizontal
Shower by EUSO will probe even larger ring areas generated in huge terrestrial
volumes larger than 2360 km^3. These highest GZK energies nu_tau astronomy are
well tuned to test the needed abundant nu fluence in GZK Z-Showering model
where ZeV (above 10^21 eV) Ultra High Energy neutrinos hit on relic light (near
0.1-3 eV masses) anti-neutrinos, in hot dark matter halos, creating boosted UHE
Z bosons. Their nucleon decay in flight may born secondaries observed on Earth
atmosphere as UHECR. The wide EUSO acceptance may test easily Z-showering
fluxes as well as GZK neutrinos at their minimal granted fluence. The rare (78)
observed upcoming terrestrial gamma flashes observed by BATSE satellite during
last decade may be also be traces of such UPTAUs and HORTAUs.


title:
An Abundance Analysis of the New Carbon-Rich Proto-Planetary Nebula IRAS
  06530$-$0213

abstract:
  In this paper, we present a study of the proto-planetary nebula (PPN) IRAS
06530$-$0213 based on low- and high-resolution spectra. The low-resolution
spectrum shows that star is an F5 supergiant with molecular C$_{2}$ and C$_{3}$
and enhanced s-process lines. From the high-resolution spectra, the following
atmospheric parameters were determined: $T_{\rm eff}$ = 6900 K, log$g$ = 1.0
and $\xi_{\rm t}$ = 4.5. Abundance analysis shows that IRAS 06530$-$0213 is
metal-poor ([Fe/H]=$-$0.9) and overabundant in carbon ([C/Fe]=1.3), nitrogen
([N/Fe]=1.0), and s-process elements ([s-process/Fe]=1.9), indicating AGB
nucleosynthesis and deep convective mixing. From the analysis of circumstellar
C$_{2}$ and CN molecular bands in the spectrum of IRAS 06530$-$0213, an
envelope expansion velocity of V$_{\rm exp}$=~14$\pm1$ km s$^{-1}$ was
determined, a typical value for post-AGB stars. Also typical of PPNs is the
double-peaked spectral energy distribution. The properties of both the
photosphere and circumstellar envelope suggest that IRAS 06530$-$0213 is
unambiguously a low-mass, carbon-rich PPN. For comparison purposes, new,
high-resolution spectra of the well-known PPN HD 56126 (IRAS 07134+1005) was
also analyzed and compared with previous results.


title: On the rapidly cooling interior of supergalactic winds

abstract:
  The steady state numerical solution and two dimensional hydrodynamic
calculations of supergalactic winds generated by super star clusters are
presented. Two possible regimes: quasi-adiabatic and strongly radiative are
thoroughly discussed.
  It is shown that superwinds driven by compact and powerful starbursts undergo
catastrophic cooling close to their sources, and establish a temperature
distribution radically different from those obtained in the adiabatic solution.
At the same time, both velocity and density radial distributions remain almost
unchanged given the speed of the rapidly diverging flow.
  The rapid fall in temperature as a function of radius reduces the size of the
zone radiating in X-rays and decreases the superwind X-ray luminosity. At the
same time, cooling brings the 10$^4$ K boundary closer to the wind center, and
promotes the establishment of an extended ionized fast moving envelope. This
should show up as a weak and broad ($\sim 1000$ km s$^{-1}$) line emission
component at the base of the much narrower line caused by the central HII
region.


title:
Implications of WMAP Observations On the Population III Star Formation
  Processes

abstract:
  In an earlier paper (Cen 2003) we pointed out the strong likelihood for the
universal reionization to occur twice, giving rise to a larger Thomson optical
depth. Here we perform a more focused analysis of the Thomson optical depth in
light of the WMAP observations. While the current uncertainties on the observed
Thomson optical depth are still relatively large, with tau_e=0.17+-0.04 (68%)
(Kogut et al 2003), important implications on Pop III star formation processes
at high redshift can already be inferred. We are able to draw four conclusions:
(1) in the absence of a top-heavy initial stellar mass function (IMF) for Pop
III metal-free stars and without a dramatic upturn in the star formation
efficiency and ionizing photon escape fraction at high redshift (z>6), we find
tau_e =< 0.09; (2) with a top-heavy IMF for the Pop III metal-free stars and
plausible star formation efficiency and ionizing photon escape fraction, it is
expected that tau_e =< 0.12; (3) it is possible to reach tau_e = 0.15, if the
metal enrichment efficiency of the intergalactic medium by Pop III stars is
very low thus Pop III era is prolonged; (4) to reach tau_e >= 0.17 requires
either of the following two conditions: the cosmological model power index n is
positively tilted to n >= 1.03, Pop III star formation in minihalos with
molecular hydrogen cooling has an efficiency c_*(H_2,III)>0.01 (with ionizing
photon escape fraction greater than 30%). If the current observed value of
Thomson optical depth withstands future data, we will have strong observational
evidence that Pop III stars are massive and their formation efficiency may be
much higher than current theoretical works suggest. Alternatively, there may be
unknown, non-stellar ionizing sources at very high redshift.


title: Self-consistent Modelling of the interstellar medium

abstract:
  The dynamical evolution of hot optically thin plasmas in the ISM crucially
depends on the heating and cooling processes. It is essential to realize that
all physical processes that contribute operate on different time scales. In
particular detailed balancing is often violated since the statistically inverse
process of e.g. collisional ionization is recombination of an ion with two
electrons, which as a three-body collision is usually dominated by radiative
recombination, causing a departure from collisional ionization equilibrium. On
top of these differences in atomic time scales, hot plasmas are often in a
dynamical state, thereby introducing another time scale, which can be the
shortest one. The non-equilibrium effects will be illustrated and discussed in
the case of galactic outflows. It will be shown, that spectral analyses of
X-ray data of edge-on galaxies show a clear signature in the form of
"multi-temperature" halos, which can most naturally be explained by the
"freezing-in" of highly ionized species in the outflow, which contribute to the
overall spectrum by DELAYED RECOMBINATION. This naturally leads to a
non-equilibrium cooling function, which modifies the dynamics, which in turn
changes the plasma densities and thermal energy budget, thus feeding back on
the ionization structure. Therefore SELF-CONSISTENT modelling is needed.


title:
Dark matter candidates: black holes and gravitationally bound black hole
  atoms in n-space

abstract:
  A comparison is made of a range of proposals to include free and bound black
holes as either a small component or the dominant constituent of dark matter.
The hypothesis that dark matter consists of atomic gravitationally bound
primordial black holes is closely examined in 3-space, as well as in n-space.
It is demonstrated that for dimensions greater than 3, stable gravitational or
electrostatic atoms cannot be bound by energy constraints. The total number of
degrees of freedom of a d-dimensional body in n-space is derived so that
equipartition of energy may be applied in the early universe. Blackbody and
Hawking radiation are generalized to n-space. A promising new approach to black
hole entropy is presented.


title:
The formation and evolution of bars in low surface brightness galaxies
  with cold dark matter halos

abstract:
  We perform several high resolution N-Body/SPH simulations of low surface
brightness galaxies (LSBs) embedded in cold dark matter halos to study how
likely is bar formation in such systems. The behavior of various collisionless
galaxy models is studied both in isolation and in the presence of a large
perturbing satellite. We also consider models with a dominant gaseous component
in the disk. We find that in general bar formation requires disk masses at
least a factor of 2 higher than those inferred for LSBs under the assumption of
a normal stellar mass-to-light ratio. Low surface density stellar disks
contributing less than 10% of the total virial mass are stable within NFW halos
spanning a range of concentrations. However, a purely gaseous disk can form a
bar even for quite low masses and for realistic temperatures provided that
cooling is very efficient (we adopt an isothermal equation of state) and that
the halo has a very low concentration, c < 5. The bars that form in these LSB
models are shorter than the typical halo scale radius - their overall angular
momentum content might be too low to affect significantly the inner dark halo
structure. Once formed, all the bars evolve into bulge-like structures in a few
Gyr and can excite spiral patterns in the surrounding disk component. The
recently discovered red LSBs show significant non-axisymmetric structure and
bulge-like components and share many of their structural properties with the
final states of our LSB models with massive disks. Our results imply that a
bulge-like component must be present in any low surface brightness galaxy that
ever went bar unstable in the past.


title: On the Origin of the Global Schmidt Law of Star Formation

abstract:
  One of the most puzzling properties of observed galaxies is the universality
of the empirical correlation between the star formation rate and average gas
surface density on kiloparsec scales (the Schmidt law). In this study I present
results of self-consistent cosmological simulations of high-redshift galaxy
formation that reproduce the Schmidt law naturally, without assuming it, and
provide some clues to this puzzle. The simulations incorporate the main
physical processes critical to various aspects of galaxy formation and have a
dynamic range high enough to identify individual star forming regions. The
results indicate that the global Schmidt law is a manifestation of the overall
density distribution of the interstellar medium (ISM). In particular, the
density probability distribution function (PDF) in the simulated disks is
similar to that observed in recent state-of-the-art modeling of the turbulent
ISM and has a well-defined generic shape. The shape of the PDF in a given
region of the disk depends on the local average surface density Sigma_g. The
dependence is such that the fraction of gas mass in the high-density tail of
the distribution scales as Sigma_g^{n-1} with n~1.4, which gives rise to the
Schmidt-like correlation. The high-density tail of the PDF is remarkably
insensitive to the inclusion of feedback and details of the cooling and heating
processes. This indicates that the global star formation rate is determined by
the supersonic turbulence driven by gravitational instabilities on large
scales, rather than stellar feedback or thermal instabilities on small scales.


title:
Global General Relativistic Magnetohydrodynamic Simulations of Accretion
  Tori

abstract:
  This paper presents an initial survey of the properties of accretion flows in
the Kerr metric from three-dimensional, general relativistic
magnetohydrodynamic simulations of accretion tori. We consider three fiducial
models of tori around rotating, both prograde and retrograde, and nonrotating
black holes; these three fiducial models are also contrasted with axisymmetric
simulations and a pseudo-Newtonian simulation with equivalent initial
conditions to delineate the limitations of these approximations.


title: Self-similarity of the Third Type in the Strong Explosion Problem

abstract:
  Propagation of a blast wave due to strong explosion in the center of a
power-law-density ($\rho \propto r^{-\alpha}$) spherically symmetric atmosphere
is studied. For adiabatic index of 5/3, the solution was known to be
self-similar, (of type I) for $\alpha <3$, self-similar (of type II) for
$\alpha >3.26$, and unknown in between. We find a self-similar solution for
$3<\alpha <3.26$, and give a (tentative) numerical proof that this solution is
indeed an asymptotic of the strong explosion. This self-similar solution is
neither of type I (dimensional analysis does not work), nor of type II (the
index of the solution is known without solving an eigenvalue problem).


title: Global Metallicities From Globulars Through To Elliptical Galaxies

abstract:
  We present narrow band data on dwarf ellipticals in nearby (Virgo, Fornax)
and intermediate redshift clusters (A2125, A2218) in order to study their mean
age and metallicities. In all four clusters, nucleated dwarf ellipticals
display colors that place them on the high metallicity end of the Milky Way
globular cluster sequence. Normal dwarf ellipticals display colors, and
resulting metallicities and ages, that align them with bright ellipticals. This
suggests that dE,N's may be the ancestors to the red GC population found around
many elliptical galaxies.


title: Narrow Band Continuum Colors of Distant Cluster Populations

abstract:
  In this poster, we present new results on narrow band photometry for A2218
($z$=0.18) and A2125 ($z$=0.25), two clusters with similar redshifts, but very
different cluster properties. A2218 is a dense, elliptical-rich cluster
(Bautz-Morgan type II) similar to Coma in its evolutionary appearance. A2125 is
a less dense, more open cluster (Bautz-Morgan type II-III), although similar in
richness. The color-magnitude relation indicates that A2125 has a more
developed blue population than A2218 (the Butcher-Oemler effect), although both
clusters have significant numbers of blue galaxies (normal star-forming or
starburst) compared to a present-day cluster. The red population are identical
in A2125 and A2218 and well fit by passive evolution models.


title: Can we have inflation with Omega > 1?

abstract:
  It is very difficult to obtain a realistic model of a closed inflationary
universe. Even if one fine-tunes the total number of e-folds to be sufficiently
small, the resulting universe typically has large density perturbations on the
scale of the horizon. We describe a class of models where this problem can be
resolved. The models are unattractive and fine-tuned, so the flatness of the
universe remains a generic prediction of inflationary cosmology. Nevertheless
one should keep in mind that with the fine-tuning at the level of about one
percent one can obtain a semi-realistic model of a closed inflationary
universe. The spectrum of density perturbations in this model may have a
cut-off on the scale of the horizon. Similar approach may be valid in
application to a compact inflationary universe with a nontrivial topology.


title: Maximum-entropy image reconstruction using wavelets

abstract:
  Wavelet functions allow the sparse and efficient representation of a signal
at different scales. Recently the application of wavelets to the denoising of
maps of cosmic microwave background (CMB) fluctuations has been proposed. The
maximum-entropy method (MEM) is also often used for enhancing astronomical
images and has been applied to CMB data. In this paper, we give a systematic
discussion of combining these two approaches by the use of the MEM in wavelet
bases for the denoising and deconvolution of CMB maps and more general images.
Certain types of wavelet transforms, such as the a trous transform, can be
viewed as a multi-channel intrinsic correlation function (ICF). We find that
the wavelet MEM has lower reconstruction residuals than conventional
pixel-basis MEM in the case when the signal-to-noise ratio is low and the point
spread function narrow. Furthermore, the Bayesian evidence for the wavelet MEM
reconstructions is generally higher for a wide range of images.
  From a Bayesian point of view, the wavelet basis thus provides a better model
of the image.


title:
Dense gas in nearby galaxies: XV. Hot ammonia in NGC253, Maffei2 and
  IC342

abstract:
  The detection of NH3 inversion lines up to the (J,K)=(6,6) level is reported
toward the central regions of the nearby galaxies NGC253, Maffei2, and IC342.
The observed lines are up to 406K (for (J,K)=(6,6)) and 848K (for the (9,9)
transition) above the ground state and reveal a warm (T_kin= 100 - 140 K)
molecular component toward all galaxies studied. The tentatively detected
(J,K)=(9,9) line is evidence for an even warmer (>400K) component toward IC342.
Toward NGC253, IC342 and Maffei2 the global beam averaged NH3 abundances are
1-2 10^-8, while the abundance relative to warm H2 is around 10^-7. The
temperatures and NH3 abundances are similar to values found for the Galactic
central region. C-shocks produced in cloud-cloud collisions can explain kinetic
temperatures and chemical abundances. In the central region of M82, however,
the NH3 emitting gas component is comparatively cool (~ 30K). It must be dense
(to provide sufficient NH3 excitation) and well shielded from dissociating
photons and comprises only a small fraction of the molecular gas mass in M82.
An important molecular component, which is warm and tenuous and characterized
by a low ammonia abundance, can be seen mainly in CO. Photon dominated regions
(PDRs) can explain both the high fraction of warm H_2 in M82 and the observed
chemical abundances.


title: Dark energy and global rotation of the Universe

abstract:
  We discuss the problem of universe acceleration driven by global rotation.
The redshift-magnitude relation is calculated and discussed in the context of
SN Ia observation data. It is shown that the dynamics of considered problem is
equivalent to the Friedmann model with additional non-interacting fluid with
negative pressure. We demonstrate that the universe acceleration increase is
due to the presence of global rotation effects, although the cosmological
constant is still required to explain the SN Ia data. We discuss some
observational constraints coming from SN Ia imposed on the behaviour of the
homogeneous Newtonian universe in which matter rotates relative local
gyroscopes. In the Newtonian theory $\Omega_{\text{r},o}$ can be identified
with $\Omega_{\omega,0}$ (only dust fluid is admissible) rotation can exist
with $\Omega_{\text{r},0}=\Omega_{\omega,0} \le 0$. However, the best-fit flat
model is the model without rotation, i.e., $\Omega_{\omega,0}=0$. In the
considered case we obtain the limit for $\Omega_{\omega,0}>-0.033$ at 1\sigma$
level$. We are also beyond the model and postulate the existence od additional
matter which scales like radiation matter and then analyse how that model fits
the SN Ia data. In this case the limits on rotation coming from BBN and CMB
anisotropies are also obtained. If we assume that the current estimates are
$\Omega_{\text{m},0}\sim 0.3$, $\Omega_{\text{r},0} \sim 10^{-4}$, then the SN
Ia data show that $\Omega_{\omega,0} \ge -0.01$ (or $\omega < 2.6 \cdot
10^{-19} \text{rad}/\text{s}$). The statistical analysis gives us that the
interval for any matter scaling like radiation is $\Omega_{\text{r},0} in
(-0.01, 0.04)$.


title:
Probing Beyond the Epoch of Hydrogen Reionization with 21 Centimeter
  Radiation

abstract:
  We use numerical simulations of hydrogen reionization by stellar sources in
the context of LCDM cosmogonies to investigate the 21 (1+z) cm radio signal
expected from the diffuse intergalactic medium (IGM) prior to the epoch of
reionization breakthrough at redshift z_ion. Two reionization scenarios are
analyzed in details: an `early reionization' case with z_ion~13, consistent
with the recent discovery by the WMAP satellite of a large optical depth to
Thomson scattering, and a `late reionization' case with z_ion~8. It is a
generic prediction of these models that the background of Lyalpha photons
produced by the early generation of stars which ultimately ionize the universe
will be sufficiently intense to make intergalactic neutral hydrogen visible
against the cosmic microwave background during the `grey age', i.e. z_ion<z<20.
Depending on the redshift of reionization breakthrough, broad-beam observations
at frequencies <150 MHz (below 100 MHz for the `early reionization' scenario)
with the next generation of radio telescopes should reveal angular fluctuations
in the sky brightness temperature in the range 5-20 mK (1 sigma) on scales
below 5 arcmin.


title:
Primordial braneworld black holes: significant enhancement of lifetimes
  through accretion

abstract:
  The Randall-Sundrum (RS-II) braneworld cosmological model with a fraction of
the total energy density in primordial black holes is considered. Due to their
5-d geometry these black holes undergo modified Hawking evaporation. It is
shown that during the high energy regime accretion from the surrounding
radiation bath is dominant compared to evaporation. This effect increases the
mass of the black holes till the onset of matter (or black hole) domination of
the total energy density. Thus black holes with even very small initial masses
could survive till several cosmologically interesting eras.


title:
Chandra Observation of NGC4449. Analysis of the X-ray Emission from a
  Dwarf Starburst Galaxy

abstract:
  We present CHANDRA X-ray data of the nearby Magellanic Irregular dwarf
starburst galaxy NGC4449. Contributions to the X-ray emission come from
discrete point sources and extended diffuse emission. The extended emission has
a complex morphology with an extent of 2.4x1.6kpc down to a flux density of
1.3E-13 erg/s/cm2/arcmin2. The best spectral fit to this emission is obtained
with an absorbed, two temperature model giving temperatures for the two gas
components of 0.28keV and 0.86keV, a total mass content of ~10^7 Msun compared
with a galactic mass of several 10^{10} Msun and a total thermal energy content
of ~2.5E55erg, with an average energy injection rate for the galaxy of a few
1E41 erg/s. Comparison of the morphology of the diffuse X-ray emission with
that of the observed Halpha emission shows similarities in the two emissions.
An expanding super-bubble is suggested by the presence of diffuse X-ray
emission within what appears to be a cavity in the Halpha emission. The
kinematics of this bubble suggest an expansion velocity of ~220km/s and a mass
injection rate of 0.14Msun/yr, but the presence of NGC4449's huge HI halo
(r~40kpc) may prevent the ejection, into the IGM, of the metal-enriched
material and energy it contains. The arcsecond-resolution of CHANDRA has
detected 24 X-ray point sources down to a completeness level corresponding to a
flux of ~2E-14 erg/s/cm2, within the optical extent of NGC4449 and analysis of
their spectra has shown them to be from at least 3 different classes of object.
As well as the known SNR in this galaxy, it also harbours several X-ray
binaries and super-soft sources. The point source X-ray luminosity function,
for the higher luminosity sources, has a slope of ~-0.51, comparable to those
of other starburst galaxies.


title: Cosmic UHE Neutrino Signatures

abstract:
  Utilizing the unique and reliable ultrasmall--$x$ predictions of the
dynamical (radiative) parton model, nominal event rates and their detailed
energy dependence caused by a variety of cosmic UHE neutrino fluxes are
calculated and analyzed. In addition, maximal Regge--model inspired small--$x$
structure functions are employed for obtaining optimal rates which do not
necessarily require `new' physics interpretations. Upward $\mu^+ +\mu^-$ event
rates are estimated by taking into account total and nadir--angle dependent
regeneration effects due to neutral current interactions. For exploring
extragalactic neutrino sources at highest energies
(\raisebox{-0.1cm}{$\stackrel{>}{\sim}$} $10^8$ GeV) with modern (future)
ground--level telescopes, we analyze horizontal air shower event rates and
shower events caused by Earth--skimming tau--neutrinos, in particular their
detailed shower-- and cosmic neutrino--energy dependence. As an illustration of
`new physics' implications we estimate the relevant horizontal air shower event
rates due to spin--2 Kaluza--Klein `graviton' exchanges in neutral current
neutrino--quark and neutrino--gluon interactions at low TeV--scales.


title: MHD Jets, Flares, and Gamma Ray Bursts

abstract:
  Recent numerical simulations of MHD jets from accretion disks are briefly
reviewed with emphasis on the scaling law for jet speed and the role of
magnetic reconnection in relation to time variability in accretion disks, jets,
and flares. On the basis of these studies, possible interpretation is given on
why statistical properties of peak intensity, peak interval, and peak duration
of gamma ray bursts (log-normal distribution) are different from those in solar
flares and black hole accretion disks (power-law distribution). From these
considerations, a new model, ``magnetized plasmoid model'', is proposed for a
central engine of gamma ray bursts.
  (see http://www.kwasan.kyoto-u.ac.jp/~shibata/grb_final/grb.pdf for pdf files
including both text and figures)


title: V, J, H and K Imaging of the Metal Rich Globular Cluster NGC 6528

abstract:
  New near-infrared observations of NGC6528 are presented. The JHK observations
complement a previous HST/NICMOS data set by Ortolani et al. (2001), in that
they sample a larger area, contain a more numerous sample of red giant stars,
and include the K band. Also, archival HST data sets (separated by 6.093 years)
were used to proper-motion decontaminate the near-infrared sample and extract a
clean VJHK catalogue. Using the present wide colour baseline, we compared the
cleaned colour-magnitude diagrams of NGC6528 with those of NGC 6553 and NGC104
and derived new estimates of reddening and distance, E(B-V)=0.55 and
(m-M)o=14.44 (7.7 kpc). Moreover, the morphology and location of the cleaned
red giant branch were used to derive a photometric estimate of the cluster
metallicity. The average of 10 metallicity indicators yields a mean value of
[M/H] ~ 0.0, and [Fe/H] ~-0.20 and +0.08 on the Zinn & West (1984) and Carretta
& Gratton (1997) revised metallicity scale, respectively. The best isochrone
fit to the cleaned K,V-K diagram is obtained for a 12.6 Gyr and Z=0.02
isochrone, i.e. the derived metallicity of NGC6528 turns out to be very close
to the mean of stars in the Baade's Window. Five AGB variable star candidates,
whose membership has to be confirmed spectroscopically, are bolometrically as
bright as the known long period variable stars in NGC6553. As discussed in
Guarnieri et al. (1997) for NGC6553, this may indicate that an `intermediate
age' population is not needed to account for the brightest stars in external
galaxies such as M32.


title: The rate and the origin of type Ia supernovae in radiogalaxies

abstract:
  An analysis of type Ia supernova (SNIa) events in early type galaxies from
Evans et al (1989) database provides strong evidence that the rate of type Ia
supernovae (SNe) in radio-loud galaxies is about 6 times higher than the rate
measured in radio-quiet galaxies, i.e. SNIa-rate$(radio-loud
galaxies)=0.47^{+0.23}_{-0.15} h^2_{50}$ SNe per century and per
10$^{10}$L$^{B}_\odot$ (SNU) as compared to SNIa-rate$(radio-quiet
galaxies)\lsim 0.080 h^2_{50}$ SNU. The exact value of the enhancement is still
rather uncertain, but is likely to be in the range $\sim 4-15$. We discuss the
possible causes of this result and we conclude that that the enhancement of
SNIa explosion rate in radio-loud galaxies has the same common origin as their
being strong radio sources, but that there is no causality link between the two
phenomena. We argue that repeated episodes of interaction and/or mergers of
early type galaxies with dwarf companions are responsible for inducing both
strong radio activity in $\sim$14% of early type galaxies, and the $\sim1$ Gyr
old stellar population needed to supply an adequate number SNIa progenitors.
Within this scenario we predict that the probability of detecting a
core-collapse SN event in radio-loud elliptical galaxies amounts to about 4% of
their SNIa events.


title: Klein-Gordon Thermal Equation for a Preplanckian Universe

abstract:
  In the paper the quantum hyperbolic equation formulated in [M. Kozlowski, J.
Marciak-Kozlowska, From Quarks to Bulk Matter, Hadronic Press, 2001], is appled
to the study of the propagation of the initial thermal state of the Universe.
It is shown that the propagation depends on the barrier height. The Planck wall
potential is introduced, V_P=hbar/8t_P=1.25 10^18 GeV where t_P is a Planck
time. For the barrier height V<V_P the master thermal equation is the modified
Klein-Gordon equation and for barrier height V>V_P the master equation is the
Klein-Gordon equation. The solutions of both type equations for Cauchy boundary
conditions are discussed.


title: Simulations of Normal Spiral Galaxies

abstract:
  Results are presented of numerical simulations of normal isolated late type
spiral galaxies. Specifically the galaxy NGC 628 is used as a template. The
method employs a TREESPH code including stellar particles, gas particles,
cooling and heating of the gas, star formation according to a Jeans criterion,
and Supernova feedback. A regular spiral disc can be generated as an
equilibrium situation of two opposing actions. On the one hand cooling and
dissipation of the gas, on the other hand gas heating by the FUV field of young
stars and SN mechanical forcing. The disc exhibits small and medium scale
spiral structure of which the multiplicity increases as a function of radius.
The theory of swing amplification can explain, both qualitatively and
quantitatively, the emerging spiral structure. In addition, swing amplification
predicts that the existence of a grand design m=2 spiral is only possible if
the disc is massive. The simulations show that the galaxy is then unstable to
bar formation. A general criterion is derived for the transition between bar
stable and unstable, depending on disc mass contribution and on disc thickness.
It seems that bar stability hardly depends on the presence of gas. A detailed
quantitative analysis is made of the emerging spiral structure and a comparison
is made with observations. That demonstrates that the structure of the
numerical isolated galaxies is not as strong and has a larger multiplicity
compared to the structure of some exemplary real galaxies. It is argued that a
grand design can only be generated by a central bar or by tidal forces
resulting from an encounter with another galaxy.


title:
The Evolution of Mass Loaded Supernova Remnants. II. Temperature
  Dependent Mass Injection Rates

abstract:
  We investigate the evolution of spherically symmetric supernova remnants in
which mass loading takes place due to conductively driven evaporation of
embedded clouds. Numerical simulations reveal significant differences between
the evolution of conductively mass loaded and the ablatively mass loaded
remnants studied in Paper I. A main difference is the way in which conductive
mass loading is extinguished at fairly early times, once the interior
temperature of the remnant falls below ~10 million K. Thus, at late times
remnants that ablatively mass load are dominated by loaded mass and thermal
energy, while those that conductively mass load are dominated by swept-up mass
and kinetic energy. Simple approximations to the remnant evolution,
complementary to those in Paper I, are given.


title:
Spatially-resolved spectrophotometric analysis and modelling of the
  Superantennae

abstract:
  We have performed spatially-resolved spectroscopy of the double-nucleated
Ultra-Luminous Infrared Galaxy IRAS 19254-7245, ``the Superantennae'', along
the line connecting the two nuclei. These data are analysed with a spectral
synthesis code, to derive the star formation and extinction properties of the
galaxy. The star formation history (SFH) of the two nuclei is similarly
characterized by two different main episodes: a recent burst, responsible of
the observed emission lines, and an older one, occurred roughly 1 Gyr ago. We
tentatively associate this bimodal SFH with a double encounter in the dynamical
history of the merger. We have complemented our study with a detailed analysis
of the broad band spectral energy distribution of the Superantennae, built from
published photometry, providing the separate optical-to-mm SEDs of the two
nuclei. Our analysis shows that: a) the southern nucleus is responsible for
about 80% of the total infrared luminosity of the system, b) the L-band
luminosity in the southern nucleus is dominated by the emission from an
obscured AGN, providing about 40 to 50% of the bolometric flux between 8 and
1000 microns; c) the northern nucleus does not show evidence for AGN emission
and appears to be in a post-starburst phase. As for the relative strengths of
the AGN and starburst components, we find that, while they are comparable at
FIR and sub-mm wavelengths, in the radio the Sy2 emission dominates by an order
of magnitude the starburst.


title:
Probing the close environment of young stellar objects with
  interferometry

abstract:
  The study of Young Stellar Objects (YSOs) is one of the most exciting topics
that can be undertaken by long baseline optical interferometry. The magnitudes
of these objects are at the edge of capabilities of current optical
interferometers, limiting the studies to a few dozen, but are well within the
capability of coming large aperture interferometers like the VLT
Interferometer, the Keck Interferometer, the Large Binocular Telescope or
'OHANA. The milli-arcsecond spatial resolution reached by interferometry probes
the very close environment of young stars, down to a tenth of an astronomical
unit. In this paper, I review the different aspects of star formation that can
be tackled by interferometry: circumstellar disks, multiplicity, jets. I
present recent observations performed with operational infrared
interferometers, IOTA, PTI and ISI, and I show why in the next future one will
extend these studies with large aperture interferometers.


title: Qualitative Theory for Lensed QSOs

abstract:
  We show that some characteristics of multiply-imaged QSO systems are very
model-independent and can be deduced accurately by simply scrutinizing the
relative positions of images and galaxy-lens center. These include the
time-ordering of the images, the orientation of the lens potential, and the
rough morphology of any ring. Other features can differ considerably between
specific models; H_0 is an example. Surprisingly, properties inherited from a
circularly symmetric lens system are model-dependent, whereas features that
arise from the breaking of circular symmetry are model-independent. We first
develop these results from some abstract geometrical ideas, then illustrate
them for some well-known systems (the quads Q2237+030, H1413+117,
HST14113+5211, PG1115+080, MG0414+0534, B1608+656, B1422+231, and RXJ0911+0551,
and the ten-image system B1933+507), and finally remark on two systems
(B1359+154 and PMN J0134-0931) where the lens properties are more complex. We
also introduce a Java applet which produces simple lens systems, and helps
further illustrate the concepts.


title: Observing the Sunyaev-Zel'dovich Effect Closer to Home

abstract:
  Hot gas trapped in a dark matter halo will produce a decrement in the surface
brightness of the microwave background, the Sunyaev-Zel'dovich (SZ) effect.
While massive clusters produce the strongest central SZ decrements, we point
out that a local galaxy halo, specifically the halo of M31, may be one of the
brightest integrated SZ sources in the sky. For various realistic gas
distributions consistent with current X-ray limits, we show that the integrated
SZ decrement from M31 will be comparable to decrements already detected in more
distant sources, provided its halo contains an appreciable quantity of hot gas.
A measurement of this decrement would provide direct information on the mass,
spatial distribution and thermodynamic state of hot gas in a low-mass halo, and
could place important constraints on current models of galaxy formation.
Detecting such an extended (~ 10 degree), low-amplitude signal will be
challenging, but should be possible with all-sky SZ maps from satellite
missions such as the Wilkinson Microwave Anisotropy Probe or the Planck
Surveyor.


title: Bowen Fluorescence from the Companion Star in X1822-371

abstract:
  We present a clear evidence for the motion of the companion star in the Low
Mass X-Ray Binary (LMXB) X1822-371. We detect NIII lambda 4640 emission moving
in antiphase with the radial velocity curve of the neutron star and produced on
the X-ray heated hemisphere of the donor star. From the motion of this feature
we derive a lower limit to the radial velocity semi-amplitude of the companion
star K2 > 300 +_ 8 km/s, which, combined with a previous determination of the
inclination angle and the pulsar's radial velocity curve, yield M2 > 0.36(2)
Msun and M1 > 1.14(6) Msun. The HeI lambda 4471 absorption line moves at lower
velocities (~ 225 km/s) and with a -0.05 phase shift, suggests a likely origin
on the gas stream near the L1 point. In addition, we detect an S-wave emission
of OVI lambda 3811 produced by illumination of the hot-spot bulge by the
central source. The Balmer lines are dominated by broad absorptions probably
due to obscuration of the accretion disc by vertically extended cool material
from the splash region and overflowing stream. We also derive a more accurate,
and significantly different (compared to earlier work) systemic velocity of
gamma = -44 +_ 5 km/s based on the motion of the HeII lambda 4686 wings and
Doppler tomography. This work confirms the power of imaging the companion stars
in LMXBs and outbursting transients using the Bowen fluorescence transitions.