title: Asteroid detection at millimetric wavelengths with the Planck survey

abstract:
  The Planck mission, originally devised for cosmological studies, offers the
opportunity to observe Solar System objects at millimetric and submillimetric
wavelengths. We concentrate in this paper on the asteroids of the Main Belt. We
intend to estimate the number of asteroids that can can be detected during the
mission and to evaluate the strength of their signal. We have rescaled the
instrument sensitivities, calculated by the LFI and HFI teams for sources fixed
in the sky, introducing some degradation factors to properly account for moving
objects. In this way a detection threshold is derived for asteroidal detection
that is related to the diameter of the asteroid and its geocentric distance. We
have developed a numerical code that models the detection of asteroids in the
LFI and HFI channels during the mission. This code perfoprms a detailed
integration of the orbits of the asteroids in the timespan of the mission and
identifies those bodies that fall in the beams of Planck and their signal
stenght. According to our simulations, a total of 397 objects will be observed
by Planck and an asteroidal body will be detected in some beam in 30% of the
total sky scan--circles. A significant fraction (in the range from ~50 to 100
objects) of the 397 asteroids will be observed with a high S/N ratio. Flux
measurements of a large sample of asteroids in the submillimeter and millimeter
range are relevant since they allow to analyze the thermal emission and its
relation to the surface and regolith properties. Furthermore, it will be
possible to check on a wider base the two standard thermal models, based on a
nonrotating or rapidly rotating sphere. Our method can also be used to separate
Solar System sources from cosmological sources in the survey. This work is
based on Planck LFI activities.


title: Seyfert Galaxies in Compact Groups

abstract:
  We present results concerning the occurrence of Seyfert galaxies in a new
large sample of Compact Groups (Focardi & Kelm 2002). Seyfert galaxies turn out
to be relatively rare (<3%), with a significant dominance of Sy2. Seyferts are
preferentially associated to Compact Groups displaying relatively high velocity
dispersion and a large number of neighbours. These characteristics,together
with an excess of ellipticals among companions, suggest that Seyferts are to be
found preferentially in rich-groups/poor-cluster like CGs.


title:
Fitting optical source counts with an infrared-defined model: insights
  into galaxy evolution

abstract:
  In order to improve the fit to the optical counts, the multi-wavelength
source count model of Rowan-Robinson (2001) is improved in two ways. First,
density evolution is incorporated to correspond to the mergers in hierarchical
models of galaxy formation. Secondly, the evolution of dust opacity is taken
into account. The luminosity and density evolution parameters and the
characteristic opacity of the local universe are allowed to vary freely and the
best overall fit to the B band is determined. This parameter set is then
translated to other wavebands, showing significant improvement of goodness of
fit in the optical, UV and near-IR bands, whilst retaining the goodness of fit
in the far-IR and submillimetre bands of the original model. A significant
fraction of the improvement of fit is shown to be due to the introduction of
optical depth history. The mean value of Av in the local universe for the
best-fitting model is 0.4. The goodness of fit to available star formation
history data is not significantly altered and the form of the evolution of the
luminosity function shown to be consistent with a semi-analytic, forward
evolution model.


title:
The discovery of 2.78 hour periodic modulation of the X-ray flux from
  globular cluster source Bo 158 in M31

abstract:
  We report the discovery of periodic intensity dips in the X-ray source XMMU
J004314.1+410724, in the globular cluster Bo158 in M31. The X-ray flux was
modulated by ~83% at a period of 2.78 hr (10017 s) in an XMM-Newton observation
taken 2002 Jan 6-7. The X-ray intensity dips show no energy dependence. We
detected weaker dips with the same period in observations taken 2000 June 25
(XMM-Newton) and 1991 June 26 (ROSAT/PSPC). The amplitude of the modulation has
been found to be anticorrelated with source X-ray flux: it becomes lower when
the source intensity rises. The energy spectrum of Bo158 was stable from
observation to observation, with a characteristic cutoff at ~4-6 keV. The
photo-electric absorption was consistent with the Galactic foreground value. No
significant spectral changes were seen in the course of the dips. If the 2.78
hr cycle is the binary period of Bo158 the system is highly compact, with a
binary separation of ~10e11 cm. The association of the source with a globular
cluster, together with spectral parameters consistent with Galactic neutron
star sources, suggests that X-rays are emitted by an accreting neutron star.
The properties of Bo 158 are somewhat reminiscent of the Galactic X-ray sources
exhibiting a dip-like modulations. We discuss two possible mechanisms
explaining the energy-independent modulation observed in Bo 158: i) the
obscuration of the central source by highly ionized material that scatters
X-rays out of the line of sight; ii) partial covering of an extended source by
an opaque absorber which occults varying fractions of the source.


title: Measurement of fast bars in a sample of early-type barred galaxies

abstract:
  We present surface photometry and stellar kinematics of a sample of 5 SB0
galaxies: ESO 139-G009, IC 874, NGC 1308, NGC 1440 and NGC 3412. We measured
their bar pattern speed using the Tremaine-Weinberg method, and derived the
ratio, R, of the corotation radius to the length of the bar semi-major axis.
For all the galaxies, R is consistent with being in the range from 1.0 and 1.4,
i.e. that they host fast bars. This represents the largest sample of galaxies
for which R has been measured this way. Taking into account the measured
distribution of R and our measurement uncertainties, we argue that this is
probably the true distribution of R. If this is the case, then the
Tremaine-Weinberg method finds a distribution of R which is in agreement with
that obtained by hydrodynamical simulations. We compared this result with
recent high-resolution N-body simulations of bars in cosmologically-motivated
dark matter halos,and conclude that these bars are not located inside centrally
concentrated dark matter halos.


title: Mocassin: A fully three-dimensional Monte Carlo photoionization code

abstract:
  The study of photoionized environments is fundamental to many astrophysical
problems. Up to the present most photoionization codes have numerically solved
the equations of radiative transfer by making the extreme simplifying
assumption of spherical symmetry. Unfortunately very few real astronomical
nebulae satisfy this requirement. To remedy these shortcomings, a
self-consistent, three-dimensional radiative transfer code has been developed
using Monte Carlo techniques. The code, Mocassin, is designed to build
realistic models of photoionized nebulae having arbitraries geometry and
density distributions with both the stellar and diffuse radiation fields
treated self-consistently. In addition, the code is capable of tretating on or
more exciting stars located at non-central locations. The gaseous region is
approximated by a cuboidal Cartesian grid composed of numerous cells. The
physical conditions within each grid cell are determined by solving the thermal
equilibrium and ionization balance equations This requires a knowledge of the
local primary and secondary radiation fields, which are calculated
self-consistently by locally simulating the individual processes of ionization
and recombination. The main structure and computational methods used in the
Mocassin code are described in this paper. Mocassin has been benchmarked
against established one-dimensional spherically symmetric codes for a number of
standard cases, as defined by the Lexington/Meudon photoionization workshops
(Pequignot et al., 1986; Ferland et al., 1995; Pequignot et al.,
2001)\citep{pequignot86,ferland95, pequignot01}. The results obtained for the
benchmark cases are satisfactory and are presented in this paper. A performance
analysis has also been carried out and is discussed here.


title: Cosmological consequences of a Chaplygin gas dark energy

abstract:
  A combination of recent observational results has given rise to what is
currently known as the dark energy problem. Although several possible
candidates have been extensively discussed in the literature to date the nature
of this dark energy component is not well understood at present. In this paper
we investigate some cosmological implications of another dark energy candidate:
an exotic fluid known as the Chaplygin gas, which is characterized by an
equation of state $p = -A/\rho$, where $A$ is a positive constant. By assuming
a flat scenario driven by non-relativistic matter plus a Chaplygin gas dark
energy we study the influence of such a component on the statistical properties
of gravitational lenses. A comparison between the predicted age of the universe
and the latest age estimates of globular clusters is also included and the
results briefly discussed. In general, we find that the behavior of this class
of models may be interpreted as an intermediary case between the standard and
$\Lambda$CDM scenarios.


title:
Fundamental galaxy parameters for radio-loud AGN and the black hole -
  radio power connection

abstract:
  We have determined the central velocity dispersion and surface brightness
profiles for a sample of powerful radio galaxies in the redshift range
0.06<z<0.31, which were selected on the basis of their young radio source. The
optical hosts follow the fundamental plane of elliptical galaxies, showing that
young radio sources reside in normal ellipticals, as do other types of radio
galaxies. As young radio sources are relatively straightforward to select and
the contributions of the AGN light to the optical spectra are minimal, these
objects can readily be used to study the evolution of the fundamental plane of
elliptical galaxies out to z=1, independently of optical selection effects. The
black hole masses of the objects in our sample have been determined using the
tight empirical relation of M_bh with central velocity dispersion, and for
literature samples of classical radio galaxies and optically selected
ellipticals. Only the optically selected in-active galaxies are found to
exhibit a correlation between M_bh and radio luminosity. In contrast, the radio
powers of the AGN in the samples do not correlate with M_bh at all, with
objects at a given black hole mass ranging over 7 orders of magnitude in radio
power. We have been able to tie in the population of powerful radio sources
with its parent population of in-active elliptical galaxies: the local black
hole mass function has been determined, which was combined with the fraction of
radio-loud black holes as function of M_bh, as determined from the optically
selected galaxy sample, to derive the local volume-density of radio galaxies
and the distribution of their black hole masses. These are shown to be
consistent with the local radio luminosity function and the distribution of
black hole masses in the radio selected samples [ABBREVIATED]


title:
Freeze-out Effects in Hydrogen and Helium Lines of SN 1987A at the Early
  Photospheric Epoch

abstract:
  We have developed a time-dependent model of ionization, excitation and energy
balance of SN 1987A atmosphere at the photospheric epoch to study early
behavior of hydrogen and helium lines. The ionization freeze-out effects play a
key role in producing both the strong H-alpha during nearly the first month and
the He I 5876 A scattering line on day 1.76. Using an extended reaction network
between hydrogen molecules and their ions demonstrates that ion-molecular
processes are likely responsible for the blue peak in H-alpha profile at the
Bochum event epoch.


title: What can exoplanets tell us about our Solar System?

abstract:
  We update our analysis of recent exoplanet data that gives us a partial
answer to the question: How does our Solar System compare to the other
planetary systems in the Universe? Exoplanets detected between January and
August 2002 strengthen the conclusion that Jupiter is a typical massive planet
rather than an outlier. The trends in detected exoplanets do not rule out the
hypothesis that our Solar System is typical. They support it.


title: How common are Earths? How common are Jupiters?

abstract:
  Among the billions of planetary systems that fill the Universe, we would like
to know how ours fits in. Exoplanet data can already be used to address the
question: How common are Jupiters? Here we discuss a simple analysis of recent
exoplanet data indicating that Jupiter is a typical massive planet rather than
an outlier. A more difficult question to address is: How common are Earths?
However, much indirect evidence suggests that wet rocky planets are common.


title: RHESSI as a Hard X-Ray Polarimeter

abstract:
  Polarization measurements of hard X-rays from solar flares can provide a
direct handle on the extent to which the accelerated electrons are beamed,
which, in turn, has important implications for particle acceleration models.
Past efforts to measured X-ray polarization have met with only limited success.
Although designed primarily as a hard X-ray imager and spectrometer, the Ramaty
High Energy Solar Spectroscopic Imager (RHESSI) is also capable of measuring
the polarization of hard X-rays (20-100 keV) from solar flares. This capability
arises from the inclusion of a small unobstructed Be scattering element that is
strategically located within the cryostat that houses the array of nine
germanium detectors. The Ge detectors are segmented, with both a front and rear
active volume. Low energy photons (below about 100 keV) can reach a rear
segment of a Ge detector only indirectly, by scattering. Low energy photons
from the Sun have a direct path to the Be and have a high probability of
Compton scattering into a rear segment of a Ge detector. The azimuthal
distribution of these scattered photons carries with it a signature of the
linear polarization of the incident flux. Sensitivity estimates, based on Monte
Carlo simulations and in-flight background measurements, indicate that a 20-100
keV polarization sensitivity of less than a few percent can be achieved for
X-class flares.


title:
What can rapid terrestrial biogenesis tell us about life in the
  universe?

abstract:
  It is sometimes asserted that the rapidity of biogenesis on Earth suggests
that life is common in the Universe. We critically examine the assumptions
inherent in this argument. Using a lottery model for biogenesis in the
Universe, we convert the observational constraints on the rapidity of
biogenesis on Earth into constraints on the probability of biogenesis on other
terrestrial planets. For example, if terrestrial biogenesis took less than 200
Myr (and we assume that it could have taken 1 billion years) then we find the
probability of biogenesis on terrestrial planets older than ~ 1 Gyr, is > 36%
at the 95% confidence level. However, there are assumptions and selection
effects that complicate this result: although we correct the analysis for the
fact that biogenesis is a prerequisite for our existence, our result depends on
the plausible assumption that rapid biogenesis is not such a prerequisite.


title: Cosmic Needles versus Cosmic Microwave Background Radiation

abstract:
  It has been suggested by a number of authors that the 2.7K cosmic microwave
background (CMB) radiation might have arisen from the radiation from Population
III objects thermalized by conducting cosmic graphite/iron needle-shaped dust.
Due to lack of an accurate solution to the absorption properties of exceedingly
elongated grains, in existing literature which studies the CMB thermalizing
process they are generally modelled as (1) needle-like spheroids in terms of
the Rayleigh approximation; (2) infinite cylinders; and (3) the antenna theory.
We show here that the Rayleigh approximation is not valid since the Rayleigh
criterion is not satisfied for highly conducting needles. We also show that the
available intergalactic iron dust, if modelled as infinite cylinders, is not
sufficient to supply the required opacity at long wavelengths to obtain the
observed isotropy and Planckian nature of the CMB. If appealing to the antenna
theory, conducting iron needles with exceedingly large elongations (10^4)
appear able to provide sufficient opacity to thermalize the CMB within the iron
density limit. But the applicability of the antenna theory to exceedingly thin
needles of nanometer/micrometer in thickness needs to be justified.


title: Simulating the Hot X-ray Emitting Gas in Elliptical Galaxies

abstract:
  We study the chemo-dynamical evolution of elliptical galaxies and their hot
X-ray emitting gas using high-resolution cosmological simulations. Our Tree
N-body/SPH code includes a self-consistent treatment of radiative cooling, star
formation, supernovae feedback, and chemical enrichment. We present a series of
LCDM cosmological simulations which trace the spatial and temporal evolution of
heavy element abundance patterns in both the stellar and gas components of
galaxies. X-ray spectra of the hot gas are constructed via the use of the
vmekal plasma model, and analysed using XSPEC with the XMM EPN response
function. Simulation end-products are quantitatively compared with the
observational data in both the X-ray and optical regime. We find that radiative
cooling is important to interpret the observed X-ray luminosity, temperature,
and metallicity of the interstellar medium of elliptical galaxies. However,
this cooled gas also leads to excessive star formation at low redshift, and
therefore results in underlying galactic stellar populations which are too blue
with respect to observations.


title: An Automated Search for Extrasolar Planet Transits

abstract:
  We are setting up a new search for transiting extrasolar planets using the
0.5m Automated Patrol Telescope at Siding Spring Observatory, Australia. We
will begin regular observations in September 2002. We expect to find ~7 new
planets per year.


title: Detecting Topology in a Nearly Flat Spherical Universe

abstract:
  When the density parameter is close to unity, the universe has a large
curvature radius independently of its being hyperbolic, flat, or spherical.
Whatever the curvature, the universe may have either a simply connected or a
multiply connected topology. In the flat case, the topology scale is arbitrary,
and there is no a priori reason for this scale to be of the same order as the
size of the observable universe. In the hyperbolic case any nontrivial topology
would almost surely be on a length scale too large to detect. In the spherical
case, by contrast, the topology could easily occur on a detectable scale. The
present paper shows how, in the spherical case, the assumption of a nearly flat
universe simplifies the algorithms for detecting a multiply connected topology,
but also reduces the amount of topology that can be seen. This is of primary
importance for the upcoming cosmic microwave background data analysis.
  This article shows that for spherical spaces one may restrict the search to
diametrically opposite pairs of circles in the circles-in-the-sky method and
still detect the cyclic factor in the standard factorization of the holonomy
group. This vastly decreases the algorithm's run time. If the search is widened
to include pairs of candidate circles whose centers are almost opposite and
whose relative twist varies slightly, then the cyclic factor along with a
cyclic subgroup of the general factor may also be detected. Unfortunately the
full holonomy group is, in general, unobservable in a nearly flat spherical
universe, and so a full 6-parameter search is unnecessary. Crystallographic
methods could also potentially detect the cyclic factor and a cyclic subgroup
of the general factor, but nothing else.


title:
Influence of gravitational lensing on the determination of the
  luminosity function of background objects

abstract:
  The distribution function of quasars with respect to apparent brightness is
given, found under the assumption that quasars are, at least partially, the
gravitationally enhanced images of the active nuclei of distant galaxies. A
Schechter law and a two-power law for the luminosity function of the sources
are used, as well as a probabilistic law of image enhancement for various
models of gravitational lenses. To find the theoretical distribution function
of quasars with respect to apparent brightness we use a theorem on the
probability density of a product of random quantities. It is shown that the
slope of this function ranges from -1 to -2 for faint quasars, like that for
ordinary galaxies. In the case of bright quasars, the slope of the apparent
brightness distribution function is determined mainly by the lensing effect and
has a lower limit of -3. The good agreement between theory and observations
suggests that statistically quasars are gravitationally enhanced images of the
active nuclei of distant galaxies. If the initial assumptions are correct, then
the luminosity function of galaxies and the apparent brightness function for
quasars are not independent but are related by means of the differential
lensing probability.


title: The Draco and Ursa Minor dwarf spheroidals. A comparative study

abstract:
  We present (V,I) photometry of two wide (~25 X 25 arcmin^2) fields centered
on the low surface brightness dwarf spheroidal galaxies Draco and Ursa Minor.
New estimates of the distance to these galaxies are provided
((m-M)_0(UMi)=19.41 \pm 0.12 and (m-M)_0(Dra)=19.84 \pm 0.14) and a comparative
study of their evolved stellar population is presented. We detect for the first
time the RGB-bump in the Luminosity Function of UMi (V_{RGB}^{Bump}=19.40\pm
0.06) while the feature is not detected in Draco. Photometric metallicity
distributions are obtained for the two galaxies and an accurate analysis to
determine the intrinsic metallicity spread is performed by means of artificial
stars experiments. (Abridged) We demonstrate that the inner region of UMi is
significantly structured, at odds with what expected for a system in dynamical
equilibrium. In particular we show that the main density peak of UMi is
off-centered with respect to the center of symmetry of the whole galaxy and it
shows a much lower ellipticity with respect to the rest of the galaxy.
Moreover, UMi stars are shown to be clustered according to two different
characteristic clustering scales, as opposite to Draco, which instead has a
very symmetric and smooth density profile. The possible consequences of this
striking structural difference on our ideas about galaxy formation are briefly
discussed. Combining our distance modulus with the more recent estimates of the
total luminosity of UMi, we find that the mass to light (M/L) ratio of this
galaxy may be as low as M/L ~ 7, a factor 5-10 lower than current estimates.


title:
A Chandra study of X-ray sources in the field of the z=2.16 radio galaxy
  MRC 1138-262

abstract:
  We present results from a Chandra X-ray Observatory study of the field X-ray
source population in the vicinity of the radio galaxy MRC 1138-262. Many
serendipitous X-ray sources are detected in an area of 8'x8' around the radio
source and 90% are identified in our deep VLT images. The space density of such
sources is higher than expected on the basis of the statistics of ROSAT and
Chandra deep surveys. The most likely explanation is in terms of a
concentration of AGN associated with the protocluster at z=2.16 which was found
around the radio galaxy in previous studies. Two sources have a confirmed
spectroscopic redshift close to that of the radio galaxy, and for three more
sources other observations suggest that they are associated with the
protocluster. Four of these five X-ray sources form, together with the radio
galaxy, a filament in the plane of the sky. The direction of the filament is
similar to that of the radio source axis, the large scale distribution of the
other protocluster members, the 150 kpc-sized emission-line halo and the
extended X-ray emission associated with the radio galaxy.
  The majority of optically identified X-ray sources in this field have
properties consistent with type I AGN, a few could be soft, low luminosity
galaxies, one is probably an obscured (type II) AGN and one is a star. These
statistics are consistent with the results of deep X-ray surveys.


title: Is NGC6752 hiding a double black hole binary in its core ?

abstract:
  NGC6752 hosts in its halo PSR J1911-5958A, a newly discovered binary
millisecond pulsar which is the most distant pulsar ever known from the core of
a globular cluster. Interestingly, its recycling history seems in conflict with
a scenario of ejection resulting from ordinary stellar dynamical encounters. A
scattering event off a binary system of two black holes with masses in the
range of 3-50 solar masses that propelled PSR J1911-5958A into its current
peripheral orbit seems more likely. It is still an observational challenge to
unveil the imprint(s) left from such a dark massive binary on cluster's stars:
PSR J1911-5958A may be the first case.


title: Unveiling black holes ejected from globular clusters

abstract:
  Was the black hole in XTE J1118+480 ejected from a globular cluster or kicked
away from the galactic disk?


title: Can the Chaplygin gas be a plausible model for dark energy?

abstract:
  In this note two cosmological models representing the flat Friedmann Universe
filled with a Chaplygin fluid, with or without dust, are analyzed in terms of
the recently proposed "statefinder" parameters. Trajectories of both models in
the parameter plane are shown to be significantly different w.r.t. "quiessence"
and "tracker" models. The generalized Chaplygin gas model with an equation of
state of the form $p = -A/\rho^{\alpha}$ is also analyzed in terms of the
statefinder parameters.


title:
Stellar populations in local star-forming galaxies. I.-Data and
  modelling procedure

abstract:
  We present an analysis of the integrated properties of the stellar
populations in the Universidad Complutense de Madrid Survey of Halpha-selected
galaxies. In this paper, the first of a series, we describe in detail the
techniques developed to model star-forming galaxies using a mixture of stellar
populations, and taking into account the observational uncertainties. We assume
a recent burst of star formation superimposed on a more evolved population. The
effects of the nebular continuum, line emission and dust attenuation are taken
into account. We also test different model assumptions including the choice of
specific evolutionary synthesis model, initial mass function, star formation
scenario and the treatment of dust extinction. Quantitative tests are applied
to determine how well these models fit our multi-wavelength observations for
the UCM sample. Our observations span the optical and near infrared, including
both photometric and spectroscopic data. Our results indicate that extinction
plays a key role in this kind of studies, revealing that low- and
high-extinction objects may require very different extinction laws and must be
treated differently. We also demonstrate that the UCM Survey galaxies are best
described by a short burst of star formation occurring within a quiescent
galaxy, rather than by continuous star formation. A detailed discussion on the
inferred parameters, such as the age, burst strength, metallicity, star
formation rate, extinction and total stellar mass for individual objects, is
presented in paper II of this series.


title:
Stellar populations in local star-forming galaxies. II.-Recent star
  formation properties and stellar masses

abstract:
  We present the integrated properties of the stellar populations in the
Universidad Complutense de Madrid Survey galaxies. Applying the techniques
described in the first paper of this series, we derive ages, burst masses and
metallicities of the newly-formed stars in our sample galaxies. The population
of young stars is responsible for the Halpha emission used to detect the
objects in the UCM Survey. We also infer total stellar masses and star
formation rates in a consistent way taking into account the evolutionary
history of each galaxy. We find that an average UCM galaxy has a total stellar
mass of ~1E10 Msun, of which about 5% has been formed in an instantaneous burst
occurred about 5 Myr ago, and sub-solar metallicity. Less than 10% of the
sample shows massive starbursts involving more than half of the total mass of
the galaxy. Several correlations are found among the derived properties. The
burst strength is correlated with the extinction and with the integrated
optical colours for galaxies with low obscuration. The current star formation
rate is correlated with the gas content. A stellar mass-metallicity relation is
also found. Our analysis indicates that the UCM Survey galaxies span a broad
range in properties between those of galaxies completely dominated by
current/recent star formation and those of normal quiescent spirals. We also
find evidence indicating that star-formation in the local universe is dominated
by galaxies considerably less massive than L*.


title:
Reddening-Independent Quasar Selection from a Wide-Field Optical and
  Near-IR Imaging Survey

abstract:
  We combine deep, wide-field near-IR and optical imaging to demonstrate a
reddening-independent quasar selection technique based on identifying outliers
in the (g-z) / (z-H) colour diagram. In three fields covering a total of ~0.7
deg^2 to a depth of m_H~18, we identified 68 quasar candidates. Follow-up
spectroscopy for 32 objects from this candidate list confirmed 22 quasars
(0.86<z<2.66), five with significant IR excesses. 2 of 8 quasars from a
subsample with U band observations do not exhibit UVX colours. From these
preliminary results, we suggest that this combined optical and near-IR
selection technique has a high selection efficiency (> 65% success rate), a
high surface density of candidates, and is relatively independent of reddening.
We discuss the implications for star/galaxy separation for IR based surveys for
quasars. We provide the coordinate list and follow-up spectroscopy for the
sample of 22 confirmed quasars.


title: Abell 3560, a galaxy cluster at the edge of a major merging event

abstract:
  In this paper we study A3560, a rich cluster at the southern periphery of the
A3558 complex, a chain of interacting clusters in the central part of the
Shapley Concentration supercluster.
  From a ROSAT-PSPC map we find that the X-ray surface brightness distribution
of A3560 is well described by two components, an elliptical King law and a more
peaked and fainter structure, which has been modeled with a Gaussian. The main
component, corresponding to the cluster, is elongated with the major axis
pointing toward the A3558 complex. The second component, centered on the
Dumb-bell galaxy which dominates the cluster, appears significantly offset (by
about 0.15 Mpc) from the cluster X-ray centroid.
  From a Beppo-SAX observation we derive the radial temperature profile,
finding that the temperature is constant (at kT~3.7 keV) up to 8 arcmin,
corresponding to 0.3 Mpc: for larger distances, the temperature significantly
drops to kT~1.7 keV. We analyze also temperature maps, dividing the cluster in
4 sectors and deriving the temperature profiles in each sector: we find that
the temperature drop is more sudden in the sectors which point towards the
A3558 complex.
  From VLA radio data, at 20 and 6 cm, we find a peculiar bright extended radio
source (J1332-3308), composed by a core (centered on the northern component of
the Dumb-bell galaxy), two lobes, a "filament" and a diffuse component. The
morphology of the source could be interpreted either with a strong interaction
of the radio source with the intracluster medium or with the model of
intermittency of the central engine.


title: Galactic Synchrotron Foreground and the CMB Polarization Measurements

abstract:
  The polarization of the Cosmic Microwave Background (CMB)is a powerful
observational tool at hand for modern cosmology. It allows to break the
degeneracy of fundamental cosmological parameters one cannot obtain using only
anisotropy data and provides new insight into conditions existing in the very
early Universe. Many experiments are now in progress whose aim is detecting
anisotropy and polarization of the CMB. Measurements of the CMB polarization
are however hampered by the presence of polarized foregrounds, above all the
synchrotron emission of our Galaxy, whose importance increases as frequency
decreases and dominates the polarized diffuse radiation at frequencies below
$\simeq 50$ GHz. In the past the separation of CMB and synchrotron was made
combining observations of the same area of sky made at different frequencies.
In this paper we show that the statistical properties of the polarized
components of the synchrotron and dust foregrounds are different from the
statistical properties of the polarized component of the CMB, therefore one can
build a statistical estimator which allows to extract the polarized component
of the CMB from single frequency data also when the polarized CMB signal is
just a fraction of the total polarized signal. This estimator improves the
signal/noise ratio for the polarized component of the CMB and reduces from
about 50 GHz to about 20 GHz the frequency above which the polarized component
of the CMB can be extracted from single frequency maps of the diffuse
radiation.


title: Abundances of Cu and Zn in metal-poor stars: clues for Galaxy evolution

abstract:
  We present new observations of copper and zinc abundances in 90 metal-poor
stars, belonging to the metallicity range -3< [Fe/H] < -0.5. The present study
is based on high resolution spectroscopic measurements collected at the Haute
Provence Observatoire (R= 42000, S/N > 100). The trend of Cu and Zn abundances
as a function of the metallicity [Fe/H] is discussed and compared to that of
other heavy elements beyond iron. We also estimate spatial velocities and
galactic orbital parameters for our target stars in order to disentangle the
population of disk stars from that of halo stars using kinematic criteria. In
the absence of a firm a priori knowledge of the nucleosynthesis mechanisms
controlling Cu and Zn production, and of the relative stellar sites, we derive
constraints on these last from the trend of the observed ratios [Cu/Fe] and
[Zn/Fe] throughout the history of the Galaxy, as well as from a few well
established properties of basic nucleosynthesis processes in stars. We thus
confirm that the production of Cu and Zn requires a number of different sources
(neutron captures in massive stars, s-processing in low and intermediate mass
stars, explosive nucleosynthesis in various supernova types). We also attempt a
ranking of the relative roles played by different production mechanisms, and
verify these hints through a simple estimate of the galactic enrichment in Cu
and Zn. In agreement with suggestions presented earlier, we find evidence that
Type Ia Supernovae must play a relevant role, especially for the production of
Cu.


title:
Search for point sources of gamma radiation above 15 TeV with the HEGRA
  - AIROBICC array

abstract:
  A search for potential point sources of very high energy gamma rays has been
carried out on the data taken simultaneously by the HEGRA AIROBICC and
Scintillator arrays from August 1994 to March 2000. The list of sought sources
includes supernova remnants, pulsars, AGNs and binary systems. The energy
threshold is around 15 TeV. For the Crab Nebula, a modest excess of 2.5
standard deviations above the cosmic ray background has been observed. Flux
upper limits (at 90% c.l.) of around 1.3 times the flux of the Crab Nebula are
obtained, on average, for the candidate sources. A different search procedure
has been used for an all-sky search which yields absolute flux upper limits
between 4 and 9 crabs depending on declination, in the band from 0 to 60
degrees.


title:
Nineteenth and Twentieth Century Clouds Over the Twenty-First Century
  Virtual Observatory

abstract:
  Physical science has changed in the century since Lord Kelvin's celebrated
essay on Nineteenth Century Clouds over the Dynamical Theory of Heat and Light,
but some things are the same. Analogs in what was happening in physics then and
what is happening in astronomy today serve to remind us why we can be confident
the Virtual Observatory of the twenty-first century will have a rich list of
challenges to explore.


title: Direct Detection of the Companion of Chi 1 Orionis

abstract:
  We present an H-band image of the companion of Chi 1 Orionis taken with the
Keck adaptive optic system and NIRC2 camera equipped with a 300mas-diameter
coronographic mask. The direct detection of this companion star enables us to
calculate dynamical masses using only Kepler's laws M_A = 1.01 +/- 0.13 M_Sun,
M_B = 0.15 +/- 0.02 M_Sun, and to study stellar evolutionary models at a wide
spread of masses. The application of Baraffe et al. (1998) pre-main-sequence
models implies an age of 70-130 Myrs. This is in conflict to the age of the
primary, a confirmed member of the Ursa Major Cluster with a canonical age of
300 Myrs. As a consequence, either the models at low masses underestimate the
age or the Ursa Major Cluster is considerably younger than assumed.


title: Inferring physical conditions in interstellar clouds of H_2

abstract:
  We have developed a code that models the formation, destruction, radiative
transfer, and vibrational/rotational excitation of H_2 in a detailed fashion.
We discuss how such codes, together with FUSE observations of H_2 in diffuse
and translucent lines of sight, may be used to infer various physical
parameters. We illustrate the effects of changes in the major physical
parameters (UV radiation field, gas density, metallicity), and we point out the
extent to which changes in one parameter may be mirrored by changes in another.
We provide an analytic formula for the molecular fraction, f_H2, as a function
of cloud column density, radiation field, and grain formation rate of H_2. Some
diffuse and translucent lines of sight may be concatenations of multiple
distinct clouds viewed together. Such situations can give rise to observables
that agree with the data, complicating the problem of uniquely identifying one
set of physical parameters with a line of sight. Finally, we illustrate the
application of our code to an ensemble of data, such as the FUSE survey of H_2
in the Large and Small Magellanic Clouds (LMC/SMC), in order to constrain the
elevated UV radiation field intensity and reduced grain formation rate of H_2
in those low- metallicity environments.


title:
Gravitational torques in spiral galaxies: gas accretion as a driving
  mechanism of galactic evolution

abstract:
  The distribution of gravitational torques and bar strengths in the local
Universe is derived from a detailed study of 163 galaxies observed in the
near-infrared. The results are compared with numerical models for spiral galaxy
evolution. It is found that the observed distribution of torques can be
accounted for only with external accretion of gas onto spiral disks. Accretion
is responsible for bar renewal - after the dissolution of primordial bars - as
well as the maintenance of spiral structures. Models of isolated, non-accreting
galaxies are ruled out. Moderate accretion rates do not explain the
observational results: it is shown that galactic disks should double their mass
in less than the Hubble time. The best fit is obtained if spiral galaxies are
open systems, still forming today by continuous gas accretion, doubling their
mass every 10 billion years.


title: Polar ring galaxies: formation and properties

abstract:
  Formation scenarios for polar ring galaxies are studied through N-body
simulatio ns that are compared with existing observations. It is shown that
polar rings ar e likely to be formed by tidal accretion of the polar material
from a gas rich d onor galaxy. The distribution of dark matter in polar ring
galaxies is studied: dark halos seem to be flattened towards the polar rings.


title:
The All-Sky Asiago-ESO/RASS QSO Survey: Clustering and Luminosity
  Function

abstract:
  The AERQS is a project aimed at the construction of an all-sky statistically
well-defined sample of local (z < 0.3) and bright (R < 15.5) QSOs. Present
uncertainties on the theoretical modeling of the QSO evolution are to be
ascribed to the relatively small number of objects observed in this magnitude
and redshift domain. We are filling this gap with a sample of 392 AGN covering
all the sky at high Galactic latitude: we present here the Clustering analysis
and the Luminosity Function of AGN at low redshift. The AERQS sets an important
zero point about the properties of the local QSO population and the
evolutionary pattern of QSOs between the present epoch and the highest
redshift.


title: Limits on cosmological variation of quark masses and strong interaction

abstract:
  We discuss limits on variation of $(m_q/\Lambda_{QCD})$. The results are
obtained by studying $n-\alpha$-interaction during Big Bang, Oklo natural
nuclear reactor data and limits on variation of the proton $g$-factor from
quasar absorpion spectra.


title:
Evaluating the disk formation paradigm in the LCDM framework:
  constraints from the Milky Way

abstract:
  We investigate the properties of a galaxy similar to the Milky Way within the
context of standard disk formation theory in a LCDM universe. Using the
standard assumption that baryons conserve specific angular momentum when they
collapse, we conclude that the mean properties of the model galaxies are in
good agreement with the Milky Way and other similar spiral galaxies, but the
predicted scatter in disk scale lengths may be too large. A model in which half
of the initial specific angular momentum is transfered to the dark matter may
produce a smaller scatter, if very compact disks are unstable and evolve into
spheroids or early type galaxies.


title: Studying Galaxy Formation with Hubble's Successor

abstract:
  In this paper, I discuss the capabilities and limitations of an 8-10 meter
ultraviolet/optical telescope in space, the proposed successor to the Hubble
Space Telescope, in the context of galaxy studies. The exquisite spatial
resolution and excellent sensitivity of such a facility would open up new
possibilities for the study of nearby dwarf galaxies ($z \la 0.5$), and for
studying the internal structure and kinematics of more luminous galaxies at
high redshift ($z \ga 2$). These applications are of particular importance
because they would address areas in which the popular Cold Dark Matter theory
is in potential conflict with observations.


title: Nucleosynthesis in Gamma Ray Burst Accretion Disks

abstract:
  We follow the nuclear reactions that occur in the accretion disks of stellar
mass black holes that are accreting at a very high rate, 0.01 to 1 solar masses
per second, as is realized in many current models for gamma-ray bursts (GRBs).
The degree of neutronization in the disk is a sensitive function of the
accretion rate, black hole mass, Kerr parameter, and disk viscosity. For high
accretion rates and low viscosity, material arriving at the black hole will
consist predominantly of neutrons. This degree of neutronization will have
important implications for the dynamics of the GRB producing jet and perhaps
for the synthesis of the r-process. For lower accretion rates and high
viscosity, as might be appropriate for the outer disk in the collapsar model,
neutron-proton equality persists allowing the possible synthesis of 56Ni in the
disk wind. 56Ni must be present to make any optically bright Type Ib supernova,
and in particular those associated with GRBs.


title:
CO Luminosity Functions For FIR and B-band Selected Galaxies and the
  First Estimate for Omega_{HI+H2}

abstract:
  We derive a non-parametric CO luminosity function using a FIR and an optical
B-band selected sample of the galaxies included in the FCRAO Extragalactic CO
Survey. The FIR selected sample is defined using the IRAS Bright Galaxy Surveys
(BGS; IRAS 60 micron flux density >= 5.24 Jy). Although our CO sample is not
complete, the normalization using the BGS reproduces the IRAS 60 micron
luminosity function in excellent agreement with those found in the literature.
Similarly, a B-band selected sample defined using the Revised Shapley-Ames
(RSA) catalog is used to derive a CO luminosity function for a comparison. A
Schechter function describes the both derived CO luminosity functions
reasonably well. Adopting the standard CO-to-H2 conversion factor, we derive a
molecular gas density of rho_{H2}=(3.1\pm 1.2)*10^7h Mo Mpc^{-3} for the local
volume. Combining with the measurements of the local HI mass density and the
helium contribution, we estimate that the total mass density of cold neutral
gas in the local universe is Omega_{gas} =(4.3 \pm 1.1)*10^{-4} h^{-1}, which
is about 20% of the total stellar mass density Omega_{stars}.


title: SMC X-1 As An Intermediate-Stage Flaring X-ray Pulsar

abstract:
  We present Rossi X-ray Timing Explorer observations of the X-ray pulsar SMC
X-1. The source is highly variable on short time scales (< 1 h), exhibiting
apparent X-ray flares occupying a significant fraction (~3 %) of the total
observing time, with a recurrence time of ~100 s. The flares seem to occur over
all binary orbital phases, and correlate with the overall variability in the
light curve. We find a total of 323 discrete flares which have a mean full
width half maximum of ~18 s. The detailed properties of SMC X-1 do not vary
significantly between the flares and the normal state, suggesting that the
flare may be an extension of the normal state persistent emission with
increased accretion rates. The flares resemble Type II X-ray bursts from GRO
J1744--28. We discuss the origin of the SMC X-1 flares in terms of a viscous
instability near the inner edge of the accretion disk around a weakly
magnetized X-ray pulsar, and find this is consistent with the interpretation
that SMC X-1 is in fact an intermediate-stage source like GRO J1744--28.


title:
On the nature of Extremely Red Objects: the 2 Ms Chandra Deep
  Field-North Survey results

abstract:
  Understanding the nature of Extremely Red Objects [EROs; (I-K)>=4] is one of
the most challenging issues in observational cosmology. Here we report on the
X-ray constraints provided by the 2 Ms Chandra Deep Field-North Survey (CDF-N).
X-ray emission has been detected from 11 out of 36 EROs (approx 30%). Five of
these have hard X-ray emission and appear to be obscured AGNs, while non-AGN
emission (star formation or normal elliptical galaxy emission) is likely to be
the dominant source of X-rays from the soft X-ray sources detected at the
faintest X-ray flux levels.


title: Planet migration

abstract:
  A planetary system may undergo significant radial rearrangement during the
early part of its lifetime. Planet migration can come about through interaction
with the surrounding planetesimal disk and the gas disk--while the latter is
still present--as well as through planet-planet interactions. We review the
major proposed migration mechanisms in the context of the planet formation
process, in our Solar System as well as in others.


title:
Three-dimensional photoionization modelling of the planetary nebula NGC
  3918

abstract:
  The three-dimensional Monte Carlo photoionization code Mocassin has been
applied to construct a realistic model of the planetary nebula NGC 3918. Three
different geometric models were tried.
  The effects of the interaction of the diffuse fields coming from two adjacent
regions of different densities were investigated. These are found to be
non-negligible, even for the relatively uncomplicated case of a biconical
geometry. We found that the ionization structure of low ionization species near
the boundaries is particularly affected.
  It is found that all three models provided acceptable matches to the
integrated nebular optical and ultraviolet spectrum. Large discrepancies were
found between all of the model predictions of infrared fine-structure line
fluxes and ISO SWS measurements. This was found to be largely due to an offset
of ~14 arcsec from the centre of the nebula that affected all of the ISO
observations of NGC 3918.
  For each model, we also produced projected emission-line maps and
position-velocity diagrams from synthetic long-slit spectra, which could be
compared to recent HST images and ground-based long-slit echelle spectra. This
comparison showed that spindle-like model B provided the best match to the
observations. We have therefore shown that although the integrated emission
line spectrum of NGC 3918 can be reproduced by all three of the
three-dimensional models investigated in this work, the capability of creating
projected emission-line maps and position-velocity diagrams from synthetic
long-slit spectra was crucial in allowing us to constrain the structure of this
object.


title: WeBo 1: A Young Barium Star Surrounded by a Ring-Like Planetary Nebula

abstract:
  WeBo 1 (PN G135.6+01.0), a previously unrecognized planetary nebula with a
remarkable thin-ring morphology, was discovered serendipitously on Digitized
Sky Survey images. The central star is found to be a late-type giant with
overabundances of carbon and s-process elements. The giant is chromospherically
active and photometrically variable, with a probable period of 4.7 days; this
suggests that the star is spotted, and that 4.7 days is its rotation period. We
propose a scenario in which one component of a binary system became an AGB star
with a dense stellar wind enriched in C and s-process elements; a portion of
the wind was accreted by the companion, contaminating its atmosphere and
spinning up its rotation. The AGB star has now become a hot subdwarf, leaving
the optical companion as a freshly contaminated barium star inside an ionized
planetary nebula.


title: Science Objectives and Early Results of the DEEP2 Redshift Survey

abstract:
  The DEIMOS spectrograph has now been installed on the Keck-II telescope and
commissioning is nearly complete. The DEEP2 Redshift Survey, which will take
approximately 120 nights at the Keck Observatory over a three year period and
has been designed to utilize the power of DEIMOS, began in the summer of 2002.
The multiplexing power and high efficiency of DEIMOS enables us to target 1000
faint galaxies per clear night. Our goal is to gather high-quality spectra of
\~60,000 galaxies with z>0.75 in order to study the properties and large scale
clustering of galaxies at z ~ 1. The survey will be executed at high spectral
resolution, $R=\lambda/\Delta \lambda \approx 5000$, allowing us to work
between the bright OH sky emission lines and to infer linewidths for many of
the target galaxies (for several thousand objects, we will obtain rotation
curves as well). The linewidth data will facilitate the execution of the
classical redshift-volume cosmological test, which can provide a precision
measurement of the equation of state of the Universe. This talk reviews the
project, summarizes our science goals and presents some early DEIMOS data.


title: Parallization of Stellar Atmosphere Codes

abstract:
  Parallel computing has turned out to be the enabling technology to solve
complex physical systems. However, the transition from shared memory, vector
computers to massively parallel, distributed memory systems and, recently, to
hybrid systems poses new challenges to the scientist. We want to present a
cook-book (with a very strong, personal bias) based on our experience with
parallization of our existing codes. Some of the general tools and
communication libraries are discussed. Our approach includes a mixture of
algorithm, domain and physical module based parallization. The advantages,
scalability and limitations of each are discussed at some examples. We want
show that it becomes easier to write parallel code with increasing complexity
of the physical problem making stellar atmosphere codes beyond the classical
assumptions very suitable.


title: Observational Limits on a Cold Distant Kuiper Belt

abstract:
  Almost all of the $>600$ known Kuiper belt objects (KBOs) have been
discovered within 50 AU of the Sun. One possible explanation for the observed
lack of KBOs beyond 50 AU is that the distant Kuiper belt is dynamically very
cold, and thus thin enough on the sky to have slipped between previous deep
survey fields. We have completed a survey designed to search for a dynamically
cold distant Kuiper belt near the invariable plane of the Solar system. In $2.3
{\rm deg}^2$ we have discovered a total of 33 KBOs and 1 Centaur, but no
objects in circular orbits beyond 50 AU. We find that we can exclude at 95% CL
the existence of a distant disk inclined by $i\le1\arcdeg$ to the invariable
plane and containing more than 1.2 times as many $D>185$ km KBOs between 50 and
60 AU as the observed inner Kuiper belt, if the distant disk is thinner than
$\sigma=1\fdg75$.


title: Energy determination in the Akeno Giant Air Shower Array experiment

abstract:
  Using data from more than ten-years of observations with the Akeno Giant Air
Shower Array (AGASA), we published a result that the energy spectrum of
ultra-high energy cosmic rays extends beyond the cutoff energy predicted by
Greisen, and Zatsepin and Kuzmin. In this paper, we reevaluate the energy
determination method used for AGASA events with respect to the lateral
distribution of shower particles, their attenuation with zenith angle, shower
front structure, delayed particles observed far from the core and other
factors. The currently assigned energies of AGASA events have an accuracy of
$\pm$25% in event-reconstruction resolution and $\pm$18% in systematic errors
around 10$^{20}$eV. This systematic uncertainty is independent of primary
energy above 10$^{19}$eV. Based on the energy spectrum from 10$^{14.5}$eV to a
few times 10$^{20}$eV determined at Akeno, there are surely events above
10$^{20}$eV and the energy spectrum extends up to a few times 10$^{20}$eV
without a GZK-cutoff.


title: Performance of the low light level CCD camera for speckle imaging

abstract:
  A new generation CCD detector called low light level CCD (L3CCD) that
performs like an intensified CCD without incorporating a micro channel plate
(MCP) for light amplification was procured and tested. A series of short
exposure images with millisecond integration time has been obtained. The L3CCD
is cooled to about $-80^\circ$ C by Peltier cooling.


title: Speckle interferometric observations of close binary stars

abstract:
  Speckle interferometric technique is employed to record a series of hundreds
of short-exposure images of several close binary stars with sub-arcsecond
separation through a narrow band filter at the Cassegrain focus of the 2.34
meter (m) Vainu Bappu telescope (VBT), situated at Vainu Bappu Observatory
(VBO), Kavalur, India. The data are recorded sequentially by a Peltier-cooled
intensified CCD camera with 10 ms exposure. The auto-correlation method is
applied to determine the angular separations and position angles of these
binary systems.


title: Time-Resolved Photometry of GK Per during the 1996 Outburst

abstract:
  GK Per is a unique cataclysmic variable star which has showed a nova
explosion as well as dwarf nova-type outbursts, and has the intermediate-polar
nature. We carried out V-band time-resolved photometry and B-band monitoring
during the 1996 outburst. This outburst lasted about 60 d and is divided into
three parts: the slow rise branch for 35 d, the gradual decay branch with a
decay rate of 20.0 d/mag for ~16 d, and the rapid decline branch with a rate of
5.6 d/mag for ~10 d. The $B-V$ color became bluest (B-V~0.18) about 10 d before
the outburst maximum, which supports an idea that the outburst in GK Per is of
the inside-out type. The spin pulse, 440-s quasi periodic oscillations (QPOs),
and ~5,000-s QPOs were detected in our light curve, as previously seen in X-ray
and optical observations. In addition, we report the discovery of ~300-s
periodicity, which is shorter than the spin period.


title:
MHD Simulations of Disk-Magnetized Star Interactions in Quiescent
  Regime: Funnel Flows and Angular Momentum Transport

abstract:
  Magnetohydrodynamic (MHD) simulations have been used to study disk accretion
to a rotating magnetized star with an aligned dipole moment. Quiescent initial
conditions were developed in order to avoid the fast initial evolution seen in
earlier studies. A set of simulations was performed for different stellar
magnetic moments and rotation rates. Simulations have shown that the disk
structure is significantly changed insidea radius r_{br} where magnetic braking
is significant. In this region the disk is strongly inhomogeneous. Radial
accretion of matter slows as it approaches the area of strong magnetic field
and a dense ring and funnel flow form at the magnetospheric radius r_m where
the magnetic pressure is equal to the total, kinetic plus thermal, pressure of
the matter.


title:
ate helium flash in V605 Aql: PNe evolution and shell formation in quick
  motion

abstract:
  The "born-again" PNe V605 Aql (A58) and V4344 Sgr (Sakurai) give us the rare
chance to follow shell formation and building of the winds in "real-time". The
high carbon abundance, and thus the high dust formation rate, enhances the
mechanisms. Thus the timescales are shortened. My data presented here gives a
quick look on the results of new observations of V605 Aql and its old planetary
nebula (PN) A58 obtained at the ESO NTT (August 2002).


title: Detection of abundant solid CO in the disk around CRBR 2422.8-3423

abstract:
  We present direct evidence for CO freeze-out in a circumstellar disk around
the edge-on class I object CRBR 2422.8-3423, observed in the M band with
VLT-ISAAC at a resolving power R~10,000. The spectrum shows strong solid CO
absorption, with a lower limit on the column density of 2.2E18 cm-2. The solid
CO column is the highest observed so far, including high-mass protostars and
background field stars. Absorption by foreground cloud material likely accounts
for less than 10% percent of the total solid CO, based on the weakness of solid
CO absorption toward nearby sources and the absence of gaseous C18O J=2-1
emission 30'' south. Gas-phase ro-vibrational CO absorption lines are also
detected with a mean temperature of 50 +/-10 K. The average gas/solid CO ratio
is ~1 along the line of sight. For an estimated inclination of 20 +/- 5 degree,
the solid CO absorption originates mostly in the cold, shielded outer part of
the flaring disk, consistent with the predominance of apolar solid CO in the
spectrum and the non-detection of solid OCN-, a thermal/ultraviolet processing
of the ice mantle. The gaseous CO comes from the warm upper layers closer to
the star.


title:
Searching for an Intrinsic Stellar Population in Compact High-Velocity
  Clouds

abstract:
  We are investigating the hypothesis that Compact High--Velocity Clouds
(CHVCs) are the left-over building blocks of Local Group galaxies. To this end,
we are searching for their embedded stellar populations using FORS at the VLT.
The search is done with single-star photometry in V and I bands, which is
sensitive to both, young and old, stellar populations. Five CHVCs of our sample
have been observed so far down to I=24. We pointed the VLT towards the highest
HI column density regions, as determined in Effelsberg radio data. In an
alternate approach, we searched 2MASS public data towards those 5 CHVCs down to
K=16. While the VLT data probe the central regions out to distance moduli of
about 27, the 2MASS data are sensitive to a population of red giant stars to
distance moduli of about 20. The 2MASS data, on the other hand, cover a much
wider field of view than the VLT data (radius of 1 degree versus FORS field of
6.8 arcmin). We did not find a stellar population intrinsic to the CHVCs in
either data. In this paper, we illustrate our search methods.


title:
Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope
  Imaging. I: Method and a Preliminary Measurement for Fornax

abstract:
  This article presents and discusses a method for measuring the proper motions
of the Galactic dwarf spheroidal galaxies using images taken with the Hubble
Space Telescope. The method involves fitting an effective point spread function
to the image of a star or quasi-stellar object to determine its centroid with
an accuracy of about 0.005 pixel (0.25 milliarcseconds) -- an accuracy
sufficient to measure the proper motion of a dwarf spheroidal galaxy using
images separated by just a few years. The data consist of images, dithered to
reduce the effects of undersampling, taken at multiple epochs with the Space
Telescope Imaging Spectrograph or the Wide Field Planetary Camera. The science
fields are in the directions of the Carina, Fornax, Sculptor, and Ursa Minor
dwarf spheroidal galaxies and each has at least one quasi-stellar object whose
identity has been established by other studies. The rate of change with time of
the centroids of the stars of the dwarf spheroidal with respect to the centroid
of the quasi-stellar object is the proper motion.
  Four independent preliminary measurements of the proper motion of Fornax for
three fields agree within their uncertainties. The weighted average of these
measurements is mu_alpha = 49 +- 13 milliarcseconds/century and mu_delta = -59
+- 13 milliarcseconds/century. The Galactocentric velocity derived from the
proper motion implies that Fornax is near perigalacticon, may not be bound to
the Milky Way, and is not a member of any of the proposed streams of galaxies
and globular clusters in the Galactic halo. If Fornax is bound, the Milky Way
must have a mass of at least (1.6 +- 0.8) x 10^{12} solar masses.


title:
Monte Carlo studies on the sensitivity of the HEGRA imaging atmospheric
  Cerenkov telescope system in observations of extended gamma-ray sources

abstract:
  In this paper, we present the results of Monte Carlo simulations of
atmospheric showers induced by diffuse gamma rays as detected by the
high-energy gamma ray astronomy (HEGRA) system of five imaging atmospheric
Cerenkov telescopes (IACTs). We have investigated the sensitivity of
observations on extended gamma ray emission over the entire field of view of
the instrument. We discuss a technique to search for extended gamma ray sources
within the field of view of the instrument. We give estimates for HEGRA
sensitivity of observations on extended TeV gamma ray sources.


title: Statistics of turbulence profile at Cerro Tololo

abstract:
  Results of 3-month continuous monitoring of turbulence profile and seeing at
Cerro Tololo (Chile) in May-July 2002 are presented. Some 28000 low-resolution
profiles were measured by a new MASS single-star turbulence monitor,
accompanied by seeing data from DIMM. The median seeing was 0.95 arcseconds.
The first 500 m contribute 60% to the total seeing, the free-atmosphere median
seeing was 0.55 arcseconds. Free-atmosphere seeing is almost never better than
0.15 arcseconds because there is always some turbulence above 12 km. A 4-day
period of calm upper atmosphere with a stable free-atmosphere seeing of 0.2-0.3
arcseconds was noted. A gain in resolution from adaptive compensation of ground
layer will be 1.7 times typically and 2-3 times during such calm periods.
Correlations of the free-atmosphere turbulence with the wind speed at
tropopause and of the ground-layer turbulence with ground wind are studied.
Temporal evolution of turbulence is characterized by recurrent bursts, their
typical duration increases from 15 minutes in low layers to 1-2 hours in high
layers. The large data base of turbulence profiles can be used to test
meso-scale modeling of astronomical seeing.


title: omega-Cen - an Ultra Compact Dwarf Galaxy ?

abstract:
  We study the merging of star clusters out of cluster aggregates similar to
Knot S in the Antennae on orbits close to the one of omega-Cen by carrying out
high resolution numerical N-body simulations. We want to constrain the
parameter space which is able to produce merger objects with similar properties
as omega-Cen.


title: On the lithium content of the globular cluster M92

abstract:
  I use literature data and a new temperature calibration to determine the Li
abundances in the globular cluster M 92. Based on the same data, Boesgaard et
al. have claimed that there is a dispersion in Li abundances in excess of
observational errors. This result has been brought as evidence for Li depletion
in metal-poor dwarfs. In the present note I argue that there is no strong
evidence for intrinsic dispersion in Li abundances, although a dispersion as
large as 0.18 dex is possible. The mean Li abundance, A(Li)=2.36, is in good
agreement with recent results for field stars and TO stars in the metal-poor
globular cluster NGC 6397. The simplest interpretation is that this constant
value represents the primordial Li abundance.


abstract:
  The Galactic Exoplanet Survey Telescope (GEST) will observe a 2 square degree
field in the Galactic bulge to search for extra-solar planets using a
gravitational lensing technique. This gravitational lensing technique is the
only method employing currently available technology that can detect Earth-mass
planets at high signal-to-noise, and can measure the frequency of terrestrial
planets as a function of Galactic position. GEST's sensitivity extends down to
the mass of Mars, and it can detect hundreds of terrestrial planets with
semi-major axes ranging from 0.7 AU to infinity. GEST will be the first truly
comprehensive survey of the Galaxy for planets like those in our own Solar
System.


title: Nonthermal Particles and Radiation Produced by Cluster Merger Shocks

abstract:
  We have developed a numerical model for the temporal evolution of particle
and photon spectra resulting from nonthermal processes at the shock fronts
formed in merging clusters of galaxies. Fermi acceleration is approximated by
injecting power-law distributions of particles during a merger event, subject
to constraints on maximum particle energies. We consider synchrotron,
bremsstrahlung, Compton, and Coulomb processes for the electrons, nuclear,
photomeson, and Coulomb processes for the protons, and knock-on electron
production during the merging process. The broadband radio through gamma-ray
emission radiated by nonthermal protons and primary and secondary electrons is
calculated both during and after the merger event. Using ROSAT observations to
establish typical parameters for the matter density profile of clusters of
galaxies, we find that typical merger shocks are weak and accelerate particles
with relatively soft spectra. We consider the prospects for detecting
nonthermal radio and gamma-ray emission from clusters of galaxies and
implications for the origin of ultra-high energy cosmic rays and the diffuse
gamma-ray background. Our results suggest that only a few of the
isotropically-distributed unidentified EGRET sources are due to shocks formed
in cluster mergers, and that only a minor contribution to the diffuse
extragalactic gamma-ray background can originate from cluster merger shocks.
Cluster merger shocks can accelerate protons to $\lesssim 10^{19}$ eV for the
standard parameters considered here. We predict that {\it GLAST} will detect
several cluster mergers and, depending on the mean magnetic fields in the
intracluster medium, the Low Frequency Array could detect anywhere from several
to several hundred.


title: The 1.6um Bump as a Photometric Redshift Indicator

abstract:
  I describe the principle of using the 1.6um H- spectral feature as a
photometric redshift indicator and demonstrate that the technique holds promise
by successfully recovering the redshifts of a small sample of z=0-1 galaxies
using only their infrared (JHKL) photometry. I then consider the applicability
of the technique to the 3.6--8um SIRTF filter set and investigate the
systematic errors that could arise in photometric redshifts from random
photometric errors or from a mismatch between target galaxies and fitting
templates in metallicity, star formation history, and amount of interstellar
dust. It appears that SIRTF near-IR data alone should be sufficient to estimate
redshift of most galaxies that are at z>~1.5 and are dominated by stellar
populations older than >~20Myr. Galaxies whose photometric fits indicate them
to be at lower redshifts, z_fit<~1.5, or dominated by very young stellar
populations, age_fit<~20Myr, suffer from severe degeneracies in photometric
redshift, and a reliable photometric determination of their redshifts will have
to include either IR observations at shorter wavelengths (H and K) or optical
data. Overall, it appears that - with care and caveats - the 1.6um bump can
provide a powerful way of estimating redshifts of distant galaxies in deep
infrared imaging surveys that will soon be provided by SIRTF, and, eventually,
by NGST.


title: Formation and evolution of bars in disc galaxies

abstract:
  I follow a bar from its formation, via its evolution, to its destruction and,
perhaps, regeneration. I discuss the main features at each stage and
particularly the role of the halo. Bars can form even in sub-maximum discs. In
fact, such bars can be stronger than bars which have grown in maximum discs.
This is due to the response of the halo and, in particular, to the exchange of
energy and angular momentum between the disc particles constituting the bar and
the halo particles at resonance with it. The bar slowdown depends on the
initial central concentration of the halo and the initial value of the disc Q.
Contrary to the halo mass distribution, the disc changes its radial density
profile considerably during the evolution. Applying the Sackett criterion, I
thus find that discs become maximum in many simulations in which they have
started off as sub-maximum. I briefly discuss the evolution if a gaseous
component is present, as well as the destruction and regeneration of bars.


title:
Near-infrared imaging and the K-z relation for radio galaxies in the 7C
  Redshift Survey

abstract:
  We present K-band imaging of all 49 radio galaxies in the 7C-I and 7C-II
regions of the 7C Redshift Survey (7CRS). The low-frequency (151 MHz) selected
7CRS sample contains all sources with flux-densities S_151 > 0.5 Jy in three
regions of the sky. We combine the K-band magnitudes of the 7CRS radio galaxies
with those from the 3CRR, 6CE and 6C* samples to investigate the nature of the
relationship between K-magnitude and redshift and whether there is any
dependence upon radio luminosity. We find that radio galaxies appear to belong
to a homogeneous population which formed the bulk of their stars at high
redshifts (z_f>5) and evolved passively from then until they reach a mean
present-day luminosity of 3L*. We find a significant difference between the
K-magnitudes of the 7CRS and 3CRR radio galaxies with the 7CRS galaxies being
\~0.55 mag fainter at all redshifts. The cause of this weak correlation between
stellar and radio luminosities probably lies in mutual correlations of these
properties with the central black hole mass. We compare the evolution-corrected
host luminosities at a constant radio luminosity and find that the typical host
luminosity (mass) increases by approximately 1L* from z~2 to z~0.5 which,
although a much smaller factor than predicted by semi-analytic models of galaxy
formation, is in line with results on optically-selected quasars. Our study has
therefore revealed that the small dispersion in stellar luminosity of radio
galaxies around 3L* includes subtle but significant differences between the
host galaxies of extreme- and moderate-power radio sources at fixed redshift,
and between those of high- and low-redshift radio sources at fixed radio
luminosity.


title:
The Hawaii-AAO K-band Galaxy Redshift Survey -- Paper I: The Local
  K-band Luminosity Function

abstract:
  We present the K-band local luminosity function derived froma sample of 1056
bright (K<15) K-selected galaxies from the Hawaii-AAO K-band redshift survey.
The Hawaii-AAO K-band redshift survey covers 4 equatorial fields with a total
area of 8.22 $\deg^2$. We derive both the non-parametric and Schechter
luminosity function from our data, and determine
$M^*(K)=-23.70\pm0.08+5\log_{10}(h)$, $\alpha=-1.37\pm0.10$ and
$\phi^*=0.013\pm0.003 h^3 \Mpc^{-3}$ for a universe with $\Omega_m=0.3$ and
$\Omega_{\Lambda}=0.7$. We also measure the K-band luminosity function for the
early- and later-type galaxies from our morphologically classified subsample.
It appears that later-type galaxies have a fainter $M^*$ and a steep slope,
while early-type galaxies have a much brighter $M^*$ and a quite flat slope in
their K-band luminosity functions. This is consistent with what have been found
in optical type dependent luminosity function. The K-band luminosity density
derived using our luminosity function is now measured at a similar redshift
depth to optical luminosity densities in the SDSS redshift survey. It is 2
times higher than the previous measurement from the shallower 2MASS sample and
resolves the previously reported discrepancies between optical and near-IR
luminosity densities.


title: Chandra Spectra of the Soft X-ray Diffuse Background

abstract:
  We present an exploratory Chandra ACIS-S3 study of the diffuse component of
the Cosmic X-ray Background in the 0.3-7 keV band for four directions at high
Galactic latitudes, with emphasis on details of the ACIS instrumental
background modeling. Observations of the dark Moon are used to model the
detector background. A comparison of the Moon data and the data obtained with
ACIS stowed outside the focal area showed that the dark Moon does not emit
significantly in our band. Point sources down to 3 10^-16 erg/s/cm2 in the
0.5-2 keV band are excluded in our two deepest observations. We estimate the
contribution of fainter, undetected sources to be less than 20% of the
remaining CXB flux in this band in all four pointings. In the 0.3-1 keV band,
the diffuse signal varies strongly from field to field and contributes between
55% and 90% of the total CXB signal. It is dominated by emission lines that can
be modeled by a kT=0.1-0.4 keV plasma. In particular, the two fields located
away from bright Galactic features show a prominent line blend at E=580 eV (O
VII + O VIII) and a possible line feature at E~300 eV. The two pointings toward
the North Polar Spur exhibit a brighter O blend and additional bright lines at
730-830 eV (Fe XVII). We measure the total 1-2 keV flux of (1.0-1.2 +-0.2)
10^-15 erg/s/cm2/arcmin (mostly resolved), and the 2-7 keV flux of (4.0-4.5
+-1.5) 10^-15 erg/s/cm2/arcmin. At E>2 keV, the diffuse emission is consistent
with zero, to an accuracy limited by the short Moon exposure and systematic
uncertainties of the S3 background. Assuming Galactic or local origin of the
line emission, we put an upper limit of 3 10^-15 erg/s/cm2/arcmin on the 0.3-1
keV extragalactic diffuse flux.


title: Decomposition of the Superwind in M82

abstract:
  We present new optical images ($B$, $V$, and H$\alpha$) of the archetypical
starburst/superwind galaxy M82 obtained with the 8.2 m Subaru Telescope to
reveal new detailed structures of the superwind-driven nebula and the
high-latitude dark lanes. The emission-line nebula is decomposed into (1) a
ridge-dominated component comprising numerous filament/loop sub-structures
whose overall morphology appears as a pair of narrow cylinders, and (2) a
diffuse component extended over much wider opening angle from the nucleus. We
suggest that these two components have different origins. The ridge-dominated
component appears as a pair of cylinders rather than a pair of cones. Since
this morphological property is similar to that of hot plasma probed by soft
X-ray, this component seems to surround the hot plasma. On the other hand, the
diffuse component may arise from dust grains which scatter stellar light from
the galaxy. Since inner region of this component is seen over the prominent ^^
^^ X"-shaped dark lanes streaming out from the nuclear region and they can be
reproduced as a conical distribution of dust grains, there seems to be a dusty
cold outflow as well as the hot one probed by soft X-ray and shock-excited
optical emission lines. If this is the case, the presence of such high-latitude
dust grains implies that neutral gaseous matter is also blown out during the
course of the superwind activity.


title: Supernova Constraints on Braneworld Dark Energy

abstract:
  Braneworld models of dark energy are examined in the light of observations of
high redshift type Ia supernovae. Braneworld models admit several novel and
even exotic possibilities which include: (i) The effective equation of state of
dark energy can be more negative than in LCDM: $w \leq -1$; (ii) A class of
braneworld models can encounter a `quiescent' future singularity at which the
energy density and the Hubble parameter remain well behaved, but higher
derivatives of the expansion factor ($\stackrel{..}{a}$, $\stackrel{...}{a}$
etc.) diverge when the future singularity is reached; (iii) The current
acceleration of the universe is a {\em transient feature} in a class of models
in which dark energy `disappears' after a certain time, giving rise to a matter
dominated universe in the future. Since horizons are absent in such a
space-time, a braneworld model with {\em transient acceleration} might help
reconcile current supernova-based observations of an accelerating universe with
the demands of string/M-theory. A maximum likelihood analysis reveals that
braneworld models satisfy the stringent demands imposed by high redshift
supernovae and a large region in parameter space agrees marginally better with
current observations than LCDM. For instance, models with $w < -1 (> -1)$
provide better agreement with data than LCDM for $\Omega_m \ggeq 0.3 (\lleq
0.25)$.


title: HI distribution and kinematics of NGC 1569

abstract:
  We present WSRT observations of high sensitivity and resolution of the
neutral hydrogen in the starburst dwarf galaxy NGC 1569. Assuming a distance of
2.2 Mpc, we find a total HI mass of 1.3 * 10^8 M_sun to be distributed in the
form of a dense, clumpy ridge surrounded by more extended diffuse HI containing
a few additional discrete features, such as a Western HI Arm and an HI bridge
reaching out to a small counterrotating companion cloud. About 10% by mass of
all HI in NGC 1569 is at unusually high velocities. Some of this HI may be
associated with the mass outflow evident from H-alpha measurements, but some
may also be associated with NGC 1569's HI companion and intervening HI bridge,
in which case, infall rather than outflow might be the cause of the discrepant
velocities. No indication of a large bubble structure was found in
position-velocity maps of the high-velocity HI. The galaxy as a whole is in
modest overall rotation, but the HI gas lacks any sign of rotation within 60''
(0.6 kpc) from the center, i.e. over most of the optical galaxy. Here,
turbulent motions resulting from the starburst appear to dominate over
rotation. In the outer disk, the rotational velocities reach a maximum of 35
\pm 6 km/s, but turbulent motion remains significant. Thus, starburst effects
are still noticeable in the outer HI disk, although they are no longer dominant
beyond 0.6 kpc. Even excluding the most extreme high-velocity HI clouds, NGC
1569 still has an unusually high mean HI velocity dispersion of sigma_v=21.3
km/s, more than double that of other dwarf galaxies.


title:
Subaru Deep Survey III. Evolution of Rest-Frame Luminosity Functions
  Based on the Photometric Redshifts for A K'-band Selected Galaxy Sample

abstract:
  We have constructed a very deep K'-selected multicolor BVRIz'JK' sample of
439 field galaxies. Photometric redshifts for sample galaxies were estimated.
The overall redshift distribution N(z) for the K'<21.0 sample is consistent
with previous observations, and for the first time we derive the N(z) down to
K'=24.0. After taking account of the dust extinction and selection effects of
the sample, the observed N(z) distribution is well described with the PLE
model, while the hierarchical galaxy formation model shows an apparent
deficiency of galaxies especially at z>2. The photometric redshift and the
best-fit SED model evaluations allow the derivation of the rest-frame K', B,
and UV(2000A) luminosity functions (LFs) and their evolutions. The rest-K' LF
shows almost no evolution up to z=3, while the rest B LF shows mild luminosity
evolution, and the rest UV LF shows strong luminosity evolution. This trend
corresponds to the evolution of the rest UV-K' color, which gets bluer with
increasing redshift. We also found that more massive galaxies are redder in
this rest-frame color in every epoch. The rest-UV LF of our K'-selected
galaxies shows a much shallower faint end slope at z=3 than that of previous
estimations for rest-UV selected Lyman break galaxies. As a consequence, the
contribution to the global star formation rate of our K'-selected galaxies is
about 42% of that derived from the integration of LF of Lyman break galaxies at
z=3. This result suggests that a large fraction of the star formation rate
density at z>1.5 comes from the contribution from the faint (M_2000A>-20) blue
galaxy population at high redshift universe that have not yet obviously been
identified. (abridged)


title:
Photometric investigation of the MBM 12 molecular cloud area in Aries.
  I. Photoelectric photometry

abstract:
  The results of photoelectric photometry in the Vilnius seven-color system are
given for 152 stars down to 12.2 mag in the area of the molecular cloud MBM 12
and the dust clouds L1454 and L1457 in Aries. The results of photometric
classification of stars are also given. The investigation of interstellar
extinction in the area is described in the next paper.


title:
Observations of the Crab Nebula with the HEGRA system of IACTs in
  convergent mode using a topological trigger

abstract:
  Routine observations of the Crab Nebula for a total of about 250 hrs,
performed with the HEGRA stereoscopic system of 5 imaging atmospheric Cerenkov
telescopes in the standard operational mode, have proven the energy threshold
of the system to be 500 GeV for small zenith angles (< 20 deg). A topological
trigger applied along with the convergent observational mode allows to reduce
noticeably the energy threshold of the system down to 350 GeV. Here we present
the relevant Monte Carlo simulations as well as the analysis results of 15 hrs
Crab Nebula data taken in such an observational mode. From the Crab Nebula
data, the final energy threshold was found to be 350 GeV. The estimated gamma
ray flux from the Crab Nebula above 350 GeV is (8.1 +- 0.1(stat) +- 0.2(syst))
10^(-11) ph cm^(-2) s^(-1), which is consistent with recent measurements
reported by the STACEE, CELESTE, CAT, and Whipple groups.


title:
Photometric investigation of the MBM 12 molecular cloud area in Aries.
  II. Cloud distance

abstract:
  Photoelectric magnitudes and color indices in the Vilnius seven-color system
for 152 stars are used to investigate the interstellar extinction in the area
of the Aries molecular cloud MBM 12, coinciding with the L1454 and L1457 dust
clouds. Spectral types, absolute magnitudes, color excesses, interstellar
extinctions and distances of the stars are determined. The plot of interstellar
extinction Av versus distance shows that the dust cloud is situated at a
distance of 325 pc, at 180 pc from the Galactic plane, and its true diameter is
about 11 pc. The interstellar extinction law in the area is found to be normal,
typical for the diffuse dust. Ten peculiar or unresolved binary stars and some
heavily reddened stars are detected.


title:
CCD photometry and classification of stars in the North America and
  Pelican nebulae region. I. Moletai photometry

abstract:
  Magnitudes and color indices in the Vilnius seven-color system are measured
for 690 stars down to ~13.2 mag in the area of the North America and Pelican
nebulae. Spectral types, absolute magnitudes, color excesses, interstellar
extinctions and distances of the stars are determined. The plots of
interstellar extinction Av versus distance for the North America Nebula and for
the dark cloud L935 show that both areas are covered by the same absorbing
cloud, situated at a distance of 600 pc. The maximal extinction in the area of
the nebula is ~3 mag, while in the dark cloud L935 it is much greater.


title:
Submillimetre and far-infrared spectral energy distributions of
  galaxies: the luminosity-temperature relation and consequences for
  photometric redshifts

abstract:
  The spectral energy distributions (SEDs) of dusty high-redshift galaxies are
poorly sampled in frequency and spatially unresolved. Their form is crucially
important for estimating the large luminosities of these galaxies accurately,
for providing circumstantial evidence concerning their power sources, and for
estimating their redshifts in the absence of spectroscopic information. We
discuss the suite of parameters necessary to describe their SEDs adequately
without introducing unnecessary complexity. We compare directly four popular
descriptions, explain the key degeneracies between the parameters in each when
confronted with data, and highlight the differences in their best-fitting
values. Using one representative SED model, we show that fitting to even a
large number of radio, submillimetre and far-infrared (far-IR) continuum
colours provides almost no power to discriminate between the redshift and dust
temperature of an observed galaxy, unless an accurate relationship with a tight
scatter exists between luminosity and temperature for the whole galaxy
population. We review our knowledge of this luminosity-dust temperature
relation derived from three galaxy samples, to better understand the size of
these uncertainties. Contrary to recent claims, we stress that far-IR-based
photometric redshifts are unlikely to be sufficiently accurate to impose useful
constraints on models of galaxy evolution: finding spectroscopic redshifts for
distant dusty galaxies will remain essential.


title: Information from the Beginning

abstract:
  Requiring black hole evaporation to be quantum-mechanically coherent imposes
a universal, finite ``holographic bound'', conjectured to be due to fundamental
discreteness of quantized gravity, on the amount of information carried by any
physical system. This bound is applied to the information budget in the
standard slow-roll model of cosmic inflation. A simple estimate suggests that
when quantum gravity is included, fluctuations during inflation have a discrete
spectrum with a limited information content, only about 10^5 bits per mode,
fixed by the inverse scalar perturbation amplitude. This scarcity of
information may allow direct observation of quantum-gravity eigenmodes in the
anisotropy of cosmic background radiation.


title: Proto-Quasars:Physical States and Observable Properties

abstract:
  Based on the radiation hydrodynamical model for the black hole(BH)
growth,incorporated with the chemical evolution of the early-type host galaxy,
we construct the coevolution model of a QSO BH and the host galaxy. As a
result, it is found that after a galactic wind epoch,the luminosity is shifted
from the host-dominant phase to the AGN-dominant phase (QSO phase) in the
timescale of a few $10^{8}$ years.The former phase corresponds to the early
stage of growing BH, and can be regarded as a ``proto-QSO'' phase. It has
observable characteristic properties (detail inthis paper).By comparing these
predictions with recent observations, radio galaxies are a possible candidate
for proto-QSOs.Also, it is anticipated that the proto-QSO phase is preceded by
an optically thick phase, which may correspond to ULIRGs.In this phase, $M_{\rm
BH}/M_{\rm bulge}$ is predicted to be much less than $10^{-3}$ and grow with
metallicity.Moreover, as precursors of ULIRGs, optically-thin star-forming
galaxies are predicted. These may be in the assembly phase of Lyman break
galaxies (LBGs) or Ly$\alpha$ emitters.


title: Black holes in the varying speed of light theory

abstract:
  We consider the effect of the \emph{Varying Speed of Light} theory on
non-rotating black holes. We show that in any varying-$c$ theory, the
Schwarzschild solution is neither static nor stationary. For a no-charged black
hole, the singularity in the Schwarzschild horizon cannot be removed by
coordinate transformation. Hence, no matter can enter the horizon, and the
interior part of the black hole is separated from the rest of the Universe. If
$\dot{c}<0$, then the size of the Schwarzschild radius increases with time. The
higher value of the speed of light in the very early Universe may have caused a
large reduction in the probability of the creation of the primordial black
holes and their population.The same analogy is also considered for the charged
black holes.


title:
Multi-wavelength observations of the TeV Blazars Mkn~421, 1ES1959+650,
  and H1426+428 with the HEGRA Cherenkov telescopes and the RXTE X-ray
  satellite

abstract:
  Recent results obtained with the HEGRA system of imaging Cherenkov telescopes
on the TeV emission of the Blazars Mkn~421 ($z=0.030$), 1ES1959+650
($z=0.047$), and H1426+428 ($z=0.129$) are reported. For Mkn~421, a close
connection of the average flux level and spectral shape has been observed
during the periods of increased activity in the years 2000 and 2001.
Simultaneously taken data with the RXTE X-ray satellite reveal a complex light
curve at X-ray and TeV energies. After a deep exposure of 94 hrs, the object
1ES1959+650 was detected at the significance level of 5.4$\sigma$ with a soft
energy spectrum following a power-law with a photon-index of $3.3 \pm 0.7$.
During recent observations in May 2002, the source has shown increased activity
with indications for a flattening of the energy spectrum.
  The high energy peaked Blazar H1426+428 has recently been identified as a
source of TeV photons. Since the source is fairly distant (z=0.129), absorption
of TeV photons due to pair-production on the optical and near infrared
extragalactic light becomes important and should leave a signature in the
observed TeV energy spectrum. Notably, the TeV energy spectrum determined with
the HEGRA system of Cherenkov telescopes agrees with the expectation of a
strongly absorbed source spectrum.


title:
Ultra-High Energy Quenching of the LPM Effect: Implications for
  GZK-Violating Events

abstract:
  Cosmic rays in the regime of 10^19-10^20 eV should not exist, according to
the GZK bound. Conflicts between data and the bound have led to suggestions
that laws of physics must be modified. We find that physical processes
neglected in the early history terminate the LPM effect, important in
calibrating the energy of electromagnetic and hadronic showers in the GZK
energy regime. The processes neglected are the direct losses of electrons and
positrons, overlooked by LPM and greatly augmented by ultra-high energy
circumstances. We present an exact formula for direct energy losses of e^+e^-
pairs in electromagnetic showers. Numerical integration in current hadronic
models shows that actual energy losses are always substantially larger than LPM
estimates, but the energy at which crossover occurs depends on models.


title: Galactic Metrics

abstract:
  The paths of stars in galaxies have circular velocity independent of their
distance from the centre of the galaxy. Newtonian mechanics with a logarithmic
potential has such paths. In relativity these paths can be taken to be
geodesics and this requirement places a resticting equation on the spacetime
metric. This equation has a non-unique spherically symmetric solution that in
the newtonian limit has a logarithmic potential. It also can be solved in terms
of a conformal factor. In particular it has solutions which are conformal to
the vacuum-Einstein solutions and such spacetimes are solutions to the
vacuum-Bach equations. Therefore it is suggested that the Bach equations
describe dynamics on galactic lenght scales.


title: The Redshift of the Lensed Object in the Einstein Ring B0218+357

abstract:
  We present a secure redshift of z=0.944\pm0.002 for the lensed object in the
Einstein ring gravitational lens B0218+357 based on five broad emission lines,
in good agreement with our preliminary value announced several years ago based
solely on the detection of a single emission line.


title:
Two-fluid matter-quintessence FLRW models: energy transfer and the
  equation of state of the universe

abstract:
  Recent observations support the view that the universe is described by a FLRW
model with $\Omega_m^0 \approx 0.3$, $\Omega_{\Lambda}^0 \approx 0.7$, and $w
\leq -1/3$ at the present epoch. There are several theoretical suggestions for
the cosmological $\Lambda$ component and for the particular form of the energy
transfer between this dark energy and matter. This gives a strong motive for a
systematic study of general properties of two-fluid FLRW models. We consider a
combination of one perfect fluid, which is quintessence with negative pressure
($p_Q = w\epsilon_Q$), and another perfect fluid, which is a mixture of
radiation and/or matter components with positive pressure ($p = \beta
\epsilon_m$), which define the associated one-fluid model ($p = \gamma
\epsilon$). We introduce a useful classification which contains 4 classes of
models defined by the presence or absence of energy transfer and by the
stationarity ($w = const.$ and $\beta = const.$) or/and non stationarity ($w$
or $\beta$ time dependent) of the equations of state. It is shown that, for
given $w$ and $\beta$, the energy transfer defines $\gamma$ and, therefore, the
total gravitating mass and dynamics of the model. We study important examples
of two-fluid FLRW models within the new classification. The behaviour of the
energy content, gravitating mass, pressure, and the energy transfer are given
as functions of the scale factor. We point out three characteristic scales,
$a_E$, $a_{\cal P}$ and $a_{\cal M}$, which separate periods of time in which
quintessence energy, pressure and gravitating mass dominate. Each sequence of
the scales defines one of 6 evolution types.


title: 15 colour photometry of Landolt SA95 standard star field

abstract:
  In this paper, we present a set of photometric observations in 15 colors of
stars in the Landolt covered by the system range from 300 nm to 1000 nm. Visual
magnitudes of the stars being studied in the field are from 10th to 20th mag.
The observational methodology and the data reduction procedures are described.
The relationships between the BATC intermediate-band system and the Landolt
UBVRI broad band system are obtained. A catalogue of the photometry has been
produced which contains the SEDs of 3613 stars. The electronic form of this
catalogue can be accessed at the CDS via anonymous ftp to cdsarc.u-strasbg.fr.


title: Photometric Redshift Determination with the BATC Multicolor System

abstract:
  In this paper, we present the methodology of photometric redshift
determination with the BATC 15-color system by using hyperz program. Both
simulated galaxies and real galaxies with known redshifts were used to estimate
the accuracy of redshifts inferred from the multicolor photometry. From the
test with simulated galaxies, the uncertainty in the inferred redshifts is
about $0.02\sim0.03$ for a given range of photometric uncertainty of $0.05 \sim
0.10$. The results with the 27 real galaxies are in good agreement with the
simulated ones. The advantage of using BATC intermediate-band system to derive
redshift is clear through the comparison with the UBVRI broad-band system. The
accuracy in redshift determination with BATC system is mainly affected by the
selection of filters and the photometric uncertainties in the observation. When
we take the limiting magnitudes of the 15 filters into account, we find that
redshift can be determined with good accuracy for galaxies with redshifts less
than 0.5, using only filters with central wavelengths shorter than 6000 A.


title: Radiation and Dynamics of Dust Particle

abstract:
  Relativistically covariant form of equation of motion for arbitrarily shaped
dust particle (neutral in charge) under the action of electromagnetic radiation
is derived -- emission, scattering and absorption of radiation is considered.
The result is presented in the form of optical quantities used in optics of
dust particles. The obtained equation of motion represents a generalization of
the Poynting-Robertson (P-R) effect, which is standardly used in orbital
evolution of dust particles in astrophysics. Simultaneous action of
electromagnetic radiation and gravitational fields of the central body -- star
-- on the motion of the particle is discussed.


title:
Electrons as Quasi-Bosons in Strong Magnetic Fields and the Stability of
  Magnetars

abstract:
  Following the recent ideas of Dryzek, Kato, Mu\~noz and Singleton \cite{R1}
(henceforth we call this paper as R1), that the composite system consisting of
an electron along with its screened electric field and within the sphere of
influence, the trapped magnetic field of white dwarf can behave like a boson,
we have argued that such an exotic transition (bosonization) of electronic
component in strongly magnetized neutron star matter in $\beta$-equilibrium can
make the existence of magnetars physically viable.


title: Outflows in Galaxies and Damped Ly-alpha System

abstract:
  Although quasar absorbers, and in particular Damped Lyman-alpha systems
(DLAs) have proven a valuable tool to study the early Universe, their exact
nature is so far poorly constrained. It has been suggested that outflows in
galaxies might account for at least part of the DLA population. Observational
evidences and models in support of this hypothesis are reviewed, including
recent observations of Lyman Break Galaxies (LBGs). Observational
counter-arguments and theoretical limitations are also given. Finally,
implications of such a model for the environment of galaxies at high-redshifts
are discussed.


title: The kinematic relationship between disk and jet in the DG Tauri system

abstract:
  We present high angular resolution millimeter wavelength continuum and
13CO(2-1) observations of the circumstellar disk surrounding the TTauri star DG
Tauri. We show that the velocity pattern in the inner regions of the disk is
consistent with Keplerian rotation about a central 0.67 Msun star. The disk
rotation is also consistent with the toroidal velocity pattern in the initial
channel of the optical jet, as inferred from HST spectra of the first
de-projected 100 AU from the source. Our observations support the tight
relationship between disk and jet kinematics postulated by the popular
magneto-centrifugal models for jet formation and collimation.