title:
Global VLBI Observations of the High Velocity HI Absorption Toward NGC
  1275

abstract:
  We present global VLBI observations of the ~8100 km s$^{-1}$ HI absorption
feature detected toward the strong radio nucleus 3C 84 of NGC 1275 in the
Perseus cluster (${V_{\rm sys}\sim}$5200 km s$^{-1}$). The observations were
obtained using the Very Long Baseline Array (VLBA), the phased Very Large Array
(VLA), and three stations of the European VLBI Network (EVN). Our results
provide the first high dynamic range image of this feature at high spectral and
spatial resolutions. We detect six distinct absorption peaks with optical
depths ranging from 0.1 to 0.45, and multiple weak features with $\tau \leq$
0.1. The compactness of the background radio source 3C 84, which has a linear
extent of only about 16 pc, limits the conclusions that can be drawn as to the
nature of the intervening object, which must be falling toward the center of
the Perseus cluster at ~3000 km s$^{-1}$. However, the detected absorption
peaks indicate the existence of several HI clouds with velocity differences and
widths similar to those seen in Galactic neutral hydrogen absorption and
similar to some of the HI absorption seen in the Large Magellanic Cloud. The
most prominent HI clouds extend from 12 to 30 mas (milliarcseconds) on the
plane of the sky. The derived HI column densities, assuming $T_{\rm s}=50$ K,
range over $(0.35-3.8)\times 10^{20}$ cm$^{-2}$, and the implied volume
densities range between 1.4 and 11 cm$^{-3}$.


title:
Runaway Acceleration of Line-Driven Winds: the Role of the Outer
  Boundary

abstract:
  Observations and theory suggest that line driven winds from hot stars and
luminous accretion disks adopt a unique, critical solution which corresponds to
maximum mass loss rate. We analyze the numerical stability of the infinite
family of shallow wind solutions, which resemble solar wind breezes, and their
transition to the critical wind. Shallow solutions are sub-critical with
respect to radiative (or Abbott) waves. These waves can propagate upstream
through shallow winds at high speeds. If the waves are not accounted for in the
Courant time step, numerical runaway results. The outer boundary condition is
equally important for wind stability. Assuming pure outflow conditions, as is
done in the literature, triggers runaway of shallow winds to the critical
solution or to accretion flow.


title:
Abbott Wave-Triggered Runaway in Line-Driven Winds from Stars and
  Accretion Disks

abstract:
  Line-driven winds from stars and accretion disks are accelerated by
scattering in numerous line transitions. The wind is believed to adopt a unique
critical solution, out of the infinite variety of shallow and steep solutions.
We study the inherent dynamics of the transition towards the critical wind. A
new runaway wind mechanism is analyzed in terms of radiative-acoustic (Abbott)
waves which are responsible for shaping the wind velocity law and fixing the
mass loss. Three different flow types result, depending on the location of
perturbations. First, if the shallow solution is perturbed sufficiently far
downstream, a single critical point forms in the flow, which is a barrier for
Abbott waves, and the solution tends to the critical one. Second, if the
shallow solution is perturbed upstream from this critical point, mass
overloading results, and the critical point is shifted inwards. This wind
exhibits a broad, stationary region of decelerating flow and its velocity law
has kinks. Third, for perturbations even further upstream, the overloaded wind
becomes time-dependent, and develops shocks and dense shells.


title: Detection and Measurement from Narrowband Tunable Filter Scans

abstract:
  The past five years have seen a rapid rise in the use of tunable filters in
many diverse fields of astronomy, through Taurus Tunable Filter (TTF)
instruments at the Anglo-Australian and William Herschel Telescopes. Over this
time we have continually refined aspects of operation and developed a
collection of special techniques to handle the data produced by these novel
imaging instruments. In this paper, we review calibration procedures and
summarize the theoretical basis for Fabry-Perot photometry that is central to
effective tunable imaging. Specific mention is made of object detection and
classification from deep narrowband surveys containing several hundred objects
per field. We also discuss methods for recognizing and dealing with artefacts
(scattered light, atmospheric effects, etc.) which can seriously compromise the
photometric integrity of the data if left untreated. Attention is paid to the
different families of ghost reflections encountered, and strategies to minimise
their presence. In our closing remarks, future directions for tunable imaging
are outlined and contrasted with the Fabry-Perot technology employed in the
current generation of tunable imagers.


title: Redshift of reionization: are we there yet?

abstract:
  Comparison of the observed evolution of the Ly-alpha transmitted flux in the
spectra of four highest redshift quasars discovered by SLOAN survey with the
theoretical prediction for this evolution based on the state-of-the-art
numerical simulations of cosmological reionization already allows one to
constrain the redshift of reionization to z = 6.2 +- 0.1s +- 0.2r, where
systematic and random errors are given respectively.


title: Cataclysmic Variables from SDSS I. The First Results

abstract:
  The commissioning year of the Sloan Digital Sky Survey has demonstrated that
many cataclysmic variables have been missed in previous surveys with brighter
limits. We report the identification of 22 cataclysmic variables, of which 19
are new discoveries and 3 are known systems (SW UMa, BH Lyn and Vir4). A
compendium of positions, colors and characteristics of these systems obtained
from the SDSS photometry and spectroscopy is presented along with data obtained
during follow-up studies with the Apache Point Observatory (APO) and Manastash
Ridge Observatory (MRO) telescopes. We have determined orbital periods for 3 of
the new systems: two show dwarf nova outbursts, and the third is a likely
magnetic system with eclipses of its region of line emission. Based on these
results, we expect the completed survey to locate at least 400 new CVs. Most of
these will be faint systems with low accretion rates that will provide new
constraints on binary evolution models.


title: New insights on the accuracy of photometric redshift measurements

abstract:
  We use the deepest and most complete redshift catalog currently available
(the Hubble Deep Field (HDF) North supplemented by new HDF South redshift data)
to minimize residuals between photometric and spectroscopic redshift estimates.
  The good agreement at z_spec < 1.5 shows that model libraries provide a good
description of the galaxy population. At z_spec > 2.0, the systematic shift
between photometric and spectroscopic redshifts decreases when the modeling of
the absorption by the interstellar and intergalactic media is refined. As a
result, in the entire redshift range 0 < z < 6, residuals between photometric
and spectroscopic redshifts are roughly halved. For objects fainter than the
spectroscopic limit, the main source of uncertainty in photometric redshifts is
related to photometric errors, and can be assessed with
  Monte Carlo simulations.


title:
Electromagnetic Radiation and Equation of Motion for Really Shaped
  Particle -- New Covariant Formulation

abstract:
  Relativistically covariant form of equation of motion for real particle
(body) under the action of electromagnetic radiation is derived. Equation of
motion in the proper frame of the particle uses the radiation pressure cross
section 3 $\times$ 3 matrix. Obtained covariant equation of motion is compared
with another covariant equation of motion which was presented more than one
year ago.


title:
X-ray Properties of Young Stellar Objects in OMC-2 and OMC-3 from the
  Chandra X-ray Observatory

abstract:
  We report X-ray results of the Chandra observation of Orion Molecular Cloud 2
and 3. A deep exposure of \sim 100 ksec detects \sim 400 X-ray sources in the
field of view of the ACIS array, providing one of the largest X-ray catalogs in
a star forming region. Coherent studies of the source detection, time
variability, and energy spectra are performed. We classify the X-ray sources
into class I, class II, and class III+MS based on the J, H, and K-band colors
of their near infrared counterparts and discuss the X-ray properties
(temperature, absorption, and time variability) along these evolutionary
phases.


title: On the gravitational instability of a dissipative medium

abstract:
  This paper shows that the ordinary Jeans wave number can be obtained as a
limiting case of a more general approach that includes dissipative effects.
Corrections to the Jeans critical mass associated to viscosity are established.
Some possible implications of the results are finally discussed.


title: Cosmic acceleration from effective forces?

abstract:
  Accelerated expansion of the Universe may result from an anti-frictional
force that is self-consistently exerted on cold dark matter (CDM). Cosmic
anti-friction is shown to give rise to an effective negative pressure of the
cosmic medium. While other models introduce a component of dark energy besides
``standard'' CDM, we resort to a phenomenological one-component model of CDM
with internal self-interactions. We demonstrate how the dynamics of the
LambdaCDM model may be recovered as a special case of cosmic anti-friction.


title: Molecular Gas Around Young Stellar Clusters

abstract:
  We have begun a survey of the molecular gas surrounding 31 young clusters in
order to investigate the link between environment and the resulting cluster. We
present here a preliminary comparison of two clusters in our sample: GGD12-15
and Mon R2. Since both clusters are located in the MonR2 molecular cloud at a
distance of 830 pc, observational biases due to differing sensitivities and
angular resolutions are avoided.


title: On Rossby waves and vortices with differential rotation

abstract:
  We present a simplified model for linearized perturbations in a fluid with
both differential rotation and differential vorticity. Without the latter the
model reduces to the classical Shearing Sheet used in the description of spiral
density waves in astrophysical disks. Without the former it reduces to the
$\beta$-plane approximation, used in the description of Rossby waves.
  Retaining both, our model allows one in general to discuss the coupling
between density waves and Rossby waves, resulting in what is known as the
``corotation resonance'' for density waves.
  Here we derive, as a first application of this model, the properties of
Rossby waves in a differentially rotating disk. We find that their propagation
is quenched by differential rotation: after a limited number of oscillations, a
Rossby wave collapses to a singular vortex, as fluid elements are sheared apart
by differential rotation. In a keplerian disk, this number of oscillations is
always lower than one. We also describe how, in a similar manner, a vortex is
sheared in a very short time.


title: Statistics of Sunyaev-Zel'dovich Cluster Surveys

abstract:
  We describe a detailed analytic model for predicting statistical quantities
(such as number counts, redshift distributions and sizes) of clusters detected
in blank-field, thermal Sunyaev-Zel'dovich effect experiments. We include in
this model the possibility of non-Gaussian density perturbations in the early
Universe and also describe a simple model for the effects of preheating on
cluster Sunyaev-Zel'dovich effect fluxes. We use this model to explore the
current state of the theoretical uncertainties present in this type of analytic
modelling, highlighting where further improvement will be necessary to fully
exploit forthcoming surveys. We then go on to explore the constraints on
cosmological parameters, the presence of any non-Gaussianity and the degree of
cluster preheating which may be obtained from both the BOLOCAM and PLANCK
experiments. We find that, providing redshifts can be measured for all detected
clusters, the BOLOCAM experiment may provide detections of non-Gaussianity or
preheating and could give approximate measurements of these effects if prior
knowledge of the various cosmological parameters is taken into account. The
PLANCK experiment Sunyaev-Zel'dovich effect cluster survey is predicted to
provide highly accurate (~5%) measurements of the degree of non-Gaussianity and
preheating while also providing measurements of several cosmological parameters
to accuracies of a few percent independent from those constraints that will be
derived from its detections of primordial cosmic microwave background
anisotropies.


title: Radio-optically selected clusters of galaxies. I. The radiogalaxy sample

abstract:
  In order to study the status and the possible evolution of clusters of
galaxies at intermediate redshifts (z ~ 0.1 - 0.3), as well as their spatial
correlation and relationship with the local environment, we built a sample of
candidate groups and clusters of galaxies using radiogalaxies as tracers of
dense environments. This technique - complementary to purely optical or X-ray
cluster selection methods - represents an interesting tool for the selection of
clusters in a wide range of richness, so to make it possible to study the
global properties of groups and clusters of galaxies, such as their
morphological content, dynamical status and number density, as well as the
effect of the environment on the radio emission phenomena. In this paper we
describe the compilation of a catalogue of 16000 radio sources in the region of
the South Galactic Pole extracted from the publicly available NRAO VLA Sky
Survey maps, and the optical identification procedure with galaxies brighter
than b_J=20.0 in the EDSGC Catalogue. The radiogalaxy sample, valuable for the
study of radio source populations down to low flux levels, consists of 1288
identifications and has been used to detect candidate groups and clusters
associated to NVSS radio sources. In a companion paper we will discuss the
cluster detection method, the cluster sample as well as first spectroscopic
results.


title: The Luminosity Function of the Host Galaxies of QSOs and BL Lac Objects

abstract:
  A clear insight of the galaxies hosting active galactic nuclei is of
fundamental importance for understanding the processes of galaxies and nuclei
formation and their cosmic evolution. A good characterization of the host
galaxies properties requires images of excellent quality in order to
disentangle the light of the galaxy from that of the bright nucleus. To this
aim HST has provided a major improvement of data on QSOs (Disney et al. 1995;
Bahcall et al. 1996, 1997; Boyce et al. 1998; McLure et al. 1999; Hamilton et
al. 2000; Kukula et al. 2001) and BL Lacs (Scarpa et al. 2000, Urry et al.
2000). We present a comparative study of low redshift QSO and BL Lac host
galaxy luminosity function (HGLF). To this aim we have considered samples of BL
Lacs (Urry et al. 2000) and QSOs (Bahcall et al. 1997; Boyce et al. 1998;
McLure et al. 1999) that have been well resolved by images obtained with WFPC2
on board of HST.


title: Radio-optically selected clusters of galaxies. II. The cluster sample

abstract:
  We present a sample of 171 candidate groups and clusters of galaxies at
intermediate redshift over an area of ~550 square degrees at the South Galactic
Pole selected by using optically identified radio sources from the NRAO VLA Sky
Survey as tracers of dense environment. Out of these 171 candidates, 76 have a
counterpart in the literature while 95 of them are previously unknown clusters.
This paper presents the cluster selection technique, based on the search of
excesses in the optical surface density of galaxies near identified
radiogalaxies, and the first spectroscopic results aimed to confirm the
presence of a cluster. Spectroscopy for 11 candidates led to the detection of 9
clusters at redshift in the range 0.13 - 0.3, with estimated velocity
dispersions ranging from values typical of clusters to those of galaxy groups.
These results show that this technique represents a powerful tool for the
selection of homogeneous samples of intermediate redshift clusters over a wide
range of richness.


title:
Reddening, Emission-Line, and Intrinsic Absorption Properties in the
  Narrow-Line Seyfert 1 Galaxy Akn 564

abstract:
  We use Hubble Space Telescope UV and optical spectra of the narrow-line
Seyfert 1 (NLS1) galaxy Akn 564 to investigate its internal reddening and
properties of its emission-line and intrinsic UV absorption gas. We find that
the extinction curve of Akn 564, derived from a comparison of its UV/optical
continuum to that of an unreddened NLS1, lacks a 2200 A bump and turns up
towards the UV at a longer wavelength (4000 A) than the standard Galactic, LMC,
and SMC curves. However, it does not show the extremely steep rise to 1200 A
that characterizes the extinction curve of the Seyfert 1 galaxy NGC 3227. The
emission-lines and continuum experience the same amount of reddening,
indicating the presence of a dust screen that is external to the narrow-line
region (NLR). Echelle spectra from the Space Telescope Imaging Spectrograph
show intrinsic UV absorption lines due to Ly-alpha, N V, C IV, Si IV, and Si
III, centered at a radial velocity of -190 km/s (relative to the host galaxy).
Photoionization models of the UV absorber indicate that it has a sufficient
columnand is at a sufficient distance from the nucleus (D > 95 pc) to be the
source of the dust screen. Thus, Akn 564 contains a dusty ``lukewarm absorber''
similar to that seen in NGC 3227.


title: On the Nature of Intrinsic Absorption in Reddened Seyfert 1 Galaxies

abstract:
  We discuss the origin of the ``dusty lukewarm absorber'', which we previously
identified in the reddened Seyfert 1 galaxies NGC 3227 and Akn 564. This
absorber is characterized by saturated UV absorption lines (C IV, N V) near the
systemic velocity of the host galaxy, and is likely responsible for reddening
both the continuum and the emission lines (including those from the narrow-line
region) from these Seyferts. From a large sample of Seyfert 1 galaxies, we find
that continuum reddening (as measured by UV color) tends to increase with
inclination of the host galaxy. Furthermore, reddened, inclined Seyfert
galaxies observed at moderate to high spectral resolution all show evidence for
dusty lukewarm absorbers. We suggest that these absorbers lie in the plane of
the host galaxy at distances > 100 pc from the nucleus, and are physically
distinct from the majority of intrinsic absorbers that are outflowing from the
nucleus.


title:
MUSICOS 1998: Optical and X-rays Observations of Flares on the RS CVn
  Binary HR 1099

abstract:
  We present simultaneous and continuous observations of H_alpha, H_beta, NaI
D_1, D_2 and HeI D_3 lines of the chromospherically active binary HR 1099. We
have observed HR 1099 for more than 3 weeks almost continuously and monitored
two flares. An increase in H_alpha, CaII H & K, H_beta, HeI D_3 and HeI
lambda6678 and a strong filling-in of the NaI D_1, D_2 and MgI b triplet during
one of the flares are observed. We have found that the flares took place at the
same phase (0.85) of the binary orbit, and both of them seems to occur near the
limb. Several X-rays flares were also detected by ASM on board RXTE. Rotational
modulation in the X-rays light curve has been detected with maximum flux when
the active K1IV star is in front.


title:
Evolution of the Ionizing Radiation Background and Star Formation in the
  Aftermath of Cosmological Reionization

abstract:
  The temporal evolution of the ionizing UV background radiation field at high
redshift provides a probe of the evolution of the early star formation rate. By
comparing the observed levels of absorption in the highest redshift quasar
spectra to the predictions of a hydrodynamic simulation, we determine the
evolution of the photoionization rate Gamma for neutral hydrogen in the
intergalactic medium, over the redshift range 4.9 < z < 6.1. After accounting
for sampling variance, we infer a sharp increase in Gamma from z~6.1 to z~5.8,
probably implying reionization at this redshift. We find a decrease in Gamma
from z~5.6 to 5.2, at 3sigma significance. This feature is a generic signature
in the aftermath of reionization, entirely consistent with the cosmological
reionization process being completed at z~6.1.
  This generic feature is a result of a significant change in the star
formation rate subsequent to the cosmological reionization. There is an abrupt
rise of the temperature of the intergalactic medium due to photo-heating, when
it is reionized. This translates to a correspondingly sudden jump in the Jeans
mass and a dramatic suppression of gas accretion onto the most abundant
(sub-galactic) halos at the epochs of interest. The star formation rate suffers
a temporary setback in the aftermath of reionization, resulting in a temporary
decrease in the amplitude of the ionizing radiation field.


title: Completeness in Photometric and Spectroscopic Searches for Clusters

abstract:
  We investigate, using simulated galaxy catalogues, the completeness of
searches for massive clusters of galaxies in redshift surveys or imaging
surveys with photometric redshift estimates, i.e. what fraction of clusters
(M>10^14/h Msun) are found in such surveys. We demonstrate that the matched
filter method provides an efficient and reliable means of identifying massive
clusters even when the redshift estimates are crude. In true redshift surveys
the method works extremely well. We demonstrate that it is possible to
construct catalogues with high completeness, low contamination and both varying
little with redshift.


title:
An Overview of the Performance and Scientific Results from the Chandra
  X-Ray Observatory (CXO)

abstract:
  The Chandra X-Ray Observatory (CXO), the x-ray component of NASA's Great
Observatories, was launched on 1999, July 23 by the Space Shuttle Columbia.
After satellite systems activation, the first x-rays focussed by the telescope
were observed on 1999, August 12. Beginning with the initial observation it was
clear that the telescope had survived the launch environment and was operating
as expected. Despite an initial surprise due to the discovery that the
telescope was far more efficient for concentrating CCD-damaging low-energy
protons than had been anticipated, the observatory is performing well and is
returning superb scientific data. Together with other space observatories, most
notably XMM-Newton, it is clear that we have entered a new era of discovery in
high-energy astrophysics.


title: Tracing Cosmic Evolution with the Las Campanas Distant Cluster Survey

abstract:
  The Las Campanas Distant Cluster Survey (LCDCS), which contains over 1000
cluster candidates at z>0.3, is a unique sample with which to probe the
evolution of both cluster galaxies and the properties of the cluster
population. Programs are now underway to utilize the LCDCS for both purposes.
We provide a brief overview of these programs, and also present new results for
the LCDCS cluster correlation function. Utilizing well-defined, approximately
dispersion-limited subsamples, we measure the angular correlation function for
clusters at z~0.5. Spatial correlation lengths are then derived via Limber
inversion. We find that the correlation length depends upon mass, as
parameterized by the mean cluster separation, in a manner that is consistent
with both local observations and CDM predictions for the clustering strength at
z=0.5.


title:
Revisiting Brightest Cluster Galaxy Evolution with the Las Campanas
  Distant Cluster Survey

abstract:
  We investigate the influence of environment on brightest cluster galaxy (BCG)
evolution using a sample of 63 clusters at 0.3 < z < 0.9 drawn primarily from
the Las Campanas Distant Cluster Survey and follow-up V, I, and K' photometry.
The luminosity evolution of the entire BCG sample is not adequately described
by a single evolutionary model. Using the integrated light from the cluster
detection as a proxy for cluster Lx and the suggestion by Burke, Collins, &
Mann, we set Lx = 2 x 10^{44} ergs/s to be the division between high and low
luminosity clusters. At high redshift (z>0.6) BCGs from low-Lx clusters are
fainter, on average, than those from high-Lx clusters and are best modeled as
having constant luminosity with redshift. The BCGs from high-Lx cluster are
best modeled as having a stellar population that formed at large redshift
(z_form > 5) and is passively evolving. However, for the entire BCG population,
the observed V-I and I-K' colors are well described by a single evolutionary
model in which the stellar populations have z_form > 5 and subsequently
passively evolve. We conclude that accretion is proportionally more significant
for BCGs in lower mass clusters at these redshifts (factor of 2 to 4 increase
in mass since z ~ 1 for the low Lx systems) and that the accreted matter is in
the form of systems with evolved stellar populations.


title: The Distance to Clusters: Correcting for Asphericity

abstract:
  X-ray and Sunyaev-Zeldovich effect observations can be combined to measure
the distance to clusters of galaxies. If the intracluster gas distribution is
not spherical, but elongated by a factor of Z along the line of sight, the
inferred distance is increased by Z, and H0 is decreased by the same factor.
Averaging the inferred value of H0 over a sufficiently large sample of clusters
can reduce any systematic bias due to cluster shapes, provided the clusters are
selected without any preferred orientation. Even so, elongation contributes
significantly to the variance in the measured distances and in the inferred
value of H0.
  With the addition of gravitational lensing observations, it is possible to
infer the three-dimensional shape of clusters, provided the gas is in
hydrostatic equilibrium. We demonstrate a specific method for finding the shape
and correcting the measured distances to individual clusters. To test this
method, we apply it to artificial observations of simple model clusters. We
recover the true distances to each of our clusters without detectable bias, and
with statistical errors due to measurement uncertainties of 4 to 6%.


title:
Recurrent Novae, Classical Novae, Symbiotic Novae, and Population II
  Novae

abstract:
  Light curve analysis of decay phase of nova outburst are summarized. Nova
duration is determined by the strong wind mass-loss which depends only on the
white dwarf mass. Fast novae correspond very massive white dwarfs and very slow
novae correspond almost lower mass limit of white dwarfs. This relation is
shown in both of classical novae and recurrent novae. Light curves are
theoretically reproduced for recurrent novae, U Sco, V394 CrA, CI Aql, V2487
Oph, RS Oph, T CrB, V745 Sco and V3890 Sgr, using binary model composed of a
white dwarf, an irradiated accretion disk, and partly irradiated companion
which is shadowed by the accretion disk. From the light curve fitting, we
conclude that most of these objects contain a very massive white dwarf close to
the Chandrasekhar mass limit (1.37 M_\sun for U Sco, V394 CrA T CrB and RS Oph,
1.35 M_\sun for V2487 Oph, V3890 Sgr and V745 Sco). They are strong candidates
of type Ia SN progenitors. Population II novae have trends of slow evolution
and small expanding velocity compared with disk novae.


title:
On the Cross-Correlation between Dark Matter Distribution and Secondary
  CMB Anisotropies by Ionized Intergalactic Medium

abstract:
  We investigate a cross-correlation between the weak gravitational lensing
field of the large-scale structure, $\kappa$, and the secondary temperature
fluctuation field, $\Delta$, of cosmic microwave background (CMB) induced by
Thomson scattering of CMB photons off the ionized medium in the mildly
nonlinear structure. The cross-correlation is expected to observationally
unveil the biasing relation between the dark matter and ionized medium
distributions in the large-scale structure. We develop a formalism for
calculating the cross-correlation function and its angular power spectrum based
on the small angle approximation. As a result, we find that leading
contribution to the cross-correlation comes from the secondary CMB fluctuation
field induced by the quadratic Doppler effects of the bulk velocity field $v$
of ionized medium. The magnitude of the cross-correlation can be estimated as
$\kaco{\kappa\Delta}\sim 10^{-10}$ on small angular scales ($l\simgt 1000$)
under the currently favored cold CDM model of the structure formation and the
simplest scenario of homogeneous reionization after a given redshift of $z_{\rm
ion}\simgt 5$. Interestingly, we find that the density-modulated quadratic
Doppler effect of $O(\delta_e v^2)$ produces the cross-correlation with the
weak lensing field that has {\em linear} dependence on the electron density
fluctuation field $\delta_e$ or equivalently on the biasing relation between
the dark matter and electron distributions. In other words, the angular power
spectrum could be both positive or negative, depending on the positive biasing
or antibiasing, respectively. Detection of the cross-correlation thus offers a
new opportunity to observationally understand the reionization history of
intergalactic medium connected to the dark matter clustering.


title: Contact Binaries in OGLE-I Database

abstract:
  We present a new catalog of 1575 contact binary stars fainter than I=18 mag
identified in OGLE-I database in the selected directions toward the Galactic
bulge and the Galactic bar. For completeness we recall here also the objects
from the formerly published OGLE catalog of contact binaries brighter than I=18
mag.
  To ease the comparison and/or distinction between contact binaries with
sinusoidal light curves and pulsating stars we also give a catalog of 506
objects with nearly sinusoidal light curves which were classified or
re-classified as pulsating variable stars.
  Present catalog contains the most numerous, observationally homogeneous
sample of contact binaries. Given are the statistical properties of the sample
relating to the distributions of brightness, periods and amplitudes of the
contact binaries.


title: The Unusually Long Duration Gamma-ray Burst GRB 000911

abstract:
  Of all the well localized gamma-ray bursts, GRB 000911 has the longest
duration (T_90 ~ 500 s), and ranks in the top 1% of BATSE bursts for fluence.
Here, we report the discovery of the afterglow of this unique burst. In order
to simultaneously fit our radio and optical observations, we are required to
invoke a model involving an hard electron distribution, p ~ 1.5 and a jet-break
time less than 1.5 day. A spectrum of the host galaxy taken 111 days after the
burst reveals a single emission line, interpreted as [OII] at a redshift z =
1.0585, and a continuum break which we interpret as the Balmer limit at this
redshift. Despite the long T_90, the afterglow of GRB 000911 is not unusual in
any other way when compared to the set of afterglows studied to date. We
conclude that the duration of the GRB plays little part in determining the
physics of the afterglow.


title:
Effective Temperatures of late L dwarfs and the onset of Methane
  signatures

abstract:
  We present a spectral analysis of a sample of late L dwarfs. We use our
latest model atmospheres and synthetic spectra and optical and K band spectra
to determine effective temperatures. We derive effective temperatures of 1400 K
to 1700 K for L8 to L6 dwarfs. The analysis demonstrates that our recent models
that rain out the formed dust completely are applicable to optical spectra of
late L dwarfs and that more consistent models are needed for intermediate L
dwarfs and for infrared spectra. We compare the results for the effective
temperatures with the temperatures of the onset of Methane formation. Our
models predict Methane absorption at 3.3micron to occur at about 400 K higher
temperatures than Methane absorption at 2.2micron. This is consistent with our
data and previous observations which show Methane absorption at 3.3micron but
not at 2.2micron in late L dwarfs.


title:
V344 Lyr: an unusual large-amplitude SU UMa-type dwarf nova with a short
  supercycle

abstract:
  We studied the large-amplitude SU UMa-type dwarf nova V344 Lyr. A combination
of our observations and reports to VSNET has yielded an extensive coverage of
outbursts between 1994 July and 2001 June. The analysis of this data showed a
mean supercycle length of 109.6 d. This value is one of the smallest among
known SU UMa-type dwarf novae (except unusual ER UMa-type dwarf novae). The
outburst amplitude of V344 Lyr (~5.5 mag) is found to be much larger than those
(3.5 +/- 0.3 mag) of SU UMa-type dwarf novae with similar supercycle lengths.
Such a deviation of the amplitude in V344 Lyr is difficult to explain by the
inclination effect. The extreme outburst parameters of V344 Lyr would require
an additional mechanism to effectively reduce the quiescent luminosity or to
increase the outburst frequency.


title:
Phase Structure of Weak MgII Absorbers: Star Forming Pockets Outside of
  Galaxies

abstract:
  A new and mysterious class of object has been revealed by the detection of
numerous weak MgII doublets in quasar absorption line spectra. The properties
of these objects will be reviewed. They are not in close proximity to luminous
galaxies, yet they have metallicities close to the solar value; they are likely
to be self-enriched. A significant fraction of the weak MgII absorbers are
constrained to be less than 10 parsecs in size, yet they present a large
cross-section for absorption, indicating that there are more than a million
times more of them than there are luminous galaxies. They could be remnants of
Population III star clusters or tracers of supernova remnants in a population
of "failed dwarf galaxies" expected in cold dark matter structure formation
scenarios.


title:
Magnetic fields in our Galaxy: How much do we know? (II) Halo fields and
  the global field structure

abstract:
  I review the large scale global magnetic field structure of our Galaxy, using
all information available for disk fields, halo fields and magnetic fields near
the Galactic center (GC). In the local disk of our Galaxy, RM and dispersion
measure (DM) data of nearby pulsars yield the strength of regular field as
1.8$\mu$G, with a pitch angle of about $8\degr$, and a bisymmetric spiral
structure. There are at least four, maybe five, field reversals from the Norma
arm to the outskirts of our Galaxy. In the thick disk or Galactic halo, large
scale toroidal magnetic fields, with opposite field directions in the Southern
and Northern Galaxy, have been revealed by the antisymmetric RM sky towards the
inner Galaxy. This signature of the A0 dynamo-mode field structure is
strengthened by the indication of a poloidal field of dipole form, that is the
transition of the RM signs probably shifted from $l\sim0\degr$ to
$l\sim+10\degr$. The local vertical field is probably a part of this dipole
field. The field structure of the A0 dynamo-mode strikingly continues towards
the region near the GC. In short, the magnetic fields in the Galactic disk have
a bisymmetric spiral structure of primordial nature, while in the halo and near
the GC the A0 dynamo seems to dominate, so that the fields consist of toroidal
fields with opposite directions below and above the Galactic plane and poloidal
fields of dipole form.


title: Electrons as quasi-bosons in magnetic white dwarfs

abstract:
  A white dwarf star achieves its equilibrium from the balancing of the
gravitational compression against the Fermi degeneracy pressure of the electron
gas. In field theory there are examples (e.g. the monopole-charge system) where
a strong magnetic field can transform a boson into a fermion or a fermion into
a boson. In some condensed matter systems (e.g. fractional quantum Hall
systems) a strong magnetic field can transform electrons into effective
fermions, or effective anyons. Based on these examples we investigate the
possibility that the strong magnetic fields of some white dwarfs may transform
some fraction of the electrons into effective bosons. This could have
consequences for the structure of highly magnetized white dwarfs. It would
alter the mass-radius relationship, and in certain instances one could envision
a scenario where a white dwarf below the Chandrasekhar limit could nevertheless
collapse into a neutron star due to a weakening of the electron degeneracy
pressure. In addition the transformation of electrons into effective bosons
could result in the electrons Bose condensing, which could speed up the cooling
rate of white dwarfs.


title:
Photometric validation of a model independent procedure to extract
  galaxy clusters

abstract:
  By means of CCD photometry in three bands (Gunn g, r, i) we investigate the
existence of 12 candidate clusters extracted via a model independent peak
finding algorithm (\cite{memsait}) from DPOSS data. The derived color-magnitude
diagrams allow us to confirm the physical nature of 9 of the cluster
candidates, and to estimate their photometric redshifts. Of the other
candidates, one is a fortuitous detection of a true cluster at z~0.4, one is a
false detection and the last is undecidable on the basis of the available data.
The accuracy of the photometric redshifts is tested on an additional sample of
8 clusters with known spectroscopic redshifts. Photometric redshifts turn out
to be accurate within z~0.01 (interquartile range).


title:
The Spectrum of Density Perturbations produced during Inflation to
  Leading Order in a General Slow-Roll Approximation

abstract:
  The standard calculation of the spectrum of density perturbations produced
during inflation assumes (i) |n-1| << 1 and (ii) |dn/dlnk| << |n-1|. Slow-roll
predicts and observations require (i), but neither slow-roll nor observations
require (ii). In this paper I derive formulae for the spectrum, spectral index,
and running of the spectral index, assuming only (i) and not (ii). I give a
large class of observationally viable examples in which these general slow-roll
formulae are accurate but the standard slow-roll formulae for the spectral
index and running are incorrect.


title: Matter in the Local Universe

abstract:
  In this contribution we review the large body of work carried out over the
past two decades to probe the dark matter in the local universe using redshift
survey and peculiar velocity data. While redshift surveys have evolved rapidly
over the years, gathering suitable peculiar velocity data and understanding the
short-comings of different analyses have proven to be a difficult task. These
difficulties have led to conflicting results which have casted some doubts on
the usefulness of cosmic flows to constrain cosmological models. Recently,
however, a consistent picture seems to be finally emerging with various methods
of analyses applied to different data sets yielding concordant results. These
favor a low-density universe, with constraints which are in good agreement with
those obtained from LSS, high-redshift supernovae and CMB studies.


title: The Stellar Population of High Redshift Galaxies

abstract:
  Using the VLT we have obtained high quality spectra of about 70 high redshift
(1- 4.6) galaxies within the FORS Deep Field (FDF). As expected most of them
turn out to be (bright) starburst galaxies and the observed spectra agree with
synthetic ones. The equivalent width of the CIV(1550) absorption line turns out
to be a good indicator for the galaxies metallicity. Furthermore our high-z
starburst galaxies show increasing metal content with decreasing redshift.
Compared with local starburst galaxies they tend to be overliminous for their
metallicity.


title: Pulsars in FIRST Observations

abstract:
  We identified 16 pulsars from the Faint Images of the Radio Sky at Twenty-cm
(FIRST) at 1.4 GHz. Their positions and total flux densities are extracted from
the FIRST catalog. Comparing the source positions with those in the PSRcatalog,
we obtained better determined positions of PSRs J1022+1001, J1518+4904,
J1652+2651, and proper motion upper limits of another three pulsars PSRs
J0751+1807, J1012+5307, J1640+2224. Proper motions of the other 10 pulsars are
consistent with the values in the catalog.


title:
Distinguishing Local and Global Influences on Galaxy Morphology: An HST
  Comparison of High and Low X-ray Luminosity Clusters

abstract:
  (Abridged) We present a morphological analysis of 17 X-ray selected clusters
at z~0.25, imaged uniformly with HST WFPC2. Eight of these clusters have low
X-ray luminosities (<10^{44} erg/s), while the remaining nine clusters have
L_x>10^{45} ergs/s. The clusters cover a relatively small range in redshift and
the data are homogeneous in terms of depth, resolution and rest wavelength
observed. We use GIM2D to fit the two dimensional surface brightness profiles
of galaxies down to M(702)<=-18.2 (Ho=50; roughly 0.01 L*) with parametric
models, and quantify their morphologies using the fractional bulge luminosity
(B/T). Within a single WFPC2 image we find that the Low-Lx clusters are
dominated by galaxies with low B/T (~0), while the High-Lx clusters are
dominated by galaxies with intermediate B/T (~0.4). We test whether this
difference could arise from a universal morphology-density relation due to
differences in the typical galaxy densities in the two samples. We find that
small differences in the B/T distributions of the two samples persist with
marginal statistical significance even when we restrict the comparison to
galaxies in environments with similar projected local galaxy densities. From
the correlations with the bulge and disk luminosity functions, we argue that
the global environment affects the population of bulges, over and above trends
seen with local density. We conclude that the destruction of disks through ram
pressure stripping or harassment is not solely responsible for the
morphology-density relation, and that bulge formation is less efficient in low
mass clusters.


title: Evolution of Li, Be and B in the Galaxy

abstract:
  In this paper we study the production of Li, Be and B nuclei by Galactic
cosmic ray spallation processes. We include three kinds of processes: (i)
spallation by light cosmic rays impinging on interstellar CNO nuclei (direct
processes); (ii) spallation by CNO cosmic ray nuclei impinging on interstellar
p and 4He (inverse processes); and (iii) alpha-alpha fusion reactions. The
latter dominate the production of 6Li and 7Li. We calculate production rates
for a closed-box Galactic model, verifying the quadratic dependence of the Be
and B abundances for low values of Z. These are quite general results and are
known to disagree with observations. We then show that the multi-zone
multi-population model we used previously for other aspects of Galactic
evolution produces quite good agreement with the linear trend observed at low
metallicities without fine tuning. We argue that reported discrepancies between
theory and observations do not represent a nucleosynthetic problem, but instead
are the consequences of inaccurate treatments of Galactic evolution.


title:
The Colour-Magnitude Relation and the Age of Galaxies in the Cluster
  AC118 at z=0.31

abstract:
  We derive the Colour-Magnitude (CM) relation for the galaxy cluster AC118 at
z=0.31 and use this relation to set constraints on the formation epoch and on
the age spread of cluster galaxies in the framework of the passive evolution
scenario. This work is based on observations at ESO NTT (OAC guaranteed time).


title:
NIR and Optical Structural Parameters of Galaxies in the Cluster AC118
  at z=0.31

abstract:
  We present some preliminary results related to a project aimed at studying
the evolution of the galaxy population in rich environments by means of the
Color-Magnitude relation and of the Fundamental Plane. We derive the NIR and
optical structural parameters for a sample of galaxies in the cluster AC118 at
z=0.31. We prove that reliable structural parameters of galaxies at z$\sim$0.3
can be still derived from ground--based observations. The NIR effective radii,
measured for the first time at this redshift, turn out to be significantly
smaller than those derived from the optical data, providing new insight into
the evolution of colour gradients in galaxies.


title: ROSAT/Chandra Observations of a Bright Transient in M81

abstract:
  We present a 10-year X-ray light curve and the spectra of a peculiar X-ray
transient in the spiral galaxy M81. The source was below the detection limit of
ROSAT PSPC before 1993, but it brightened substantially in 1993, with
luminosities exceeding the Eddington limit of a 1.5 solar-mass compact
accretor. It then faded and was not firmly detected in the ROSAT HRI and PSPC
observations after 1994. The Chandra image obtained in 2000 May, however, shows
an X-ray source at its position within the instrumental uncertainties. The
Chandra source is coincident with a star-like object in the
Digitized-Sky-Survey. A Hubble image suggests that the optical object may be
extended. While these three observations could be of the same object, which may
be an X-ray binary containing a black-hole candidate, the possibility that the
ROSAT and Chandra sources are two different objects in a dense stellar
environment cannot be ruled out. The Hubble data suggests that the optical
object may be a globular cluster yet to be identified.


title:
Vertical Distribution of Galactic Disc Stars and Gas Constrained by a
  Molecular Cloud Complex

abstract:
  We investigate the dynamical effects of a molecular cloud complex with a mass
of about 10**7 M_sun and a size of a few 100 pc on the vertical distribution of
stars and atomic hydrogen gas in a spiral galactic disc. Such massive complexes
have now been observed in a number of spiral galaxies. The extended mass
distribution in a complex, with an average mass density 6 times higher than the
Oort limit, is shown to dominate the local gravitational field. This results in
a significant redistribution of the surrounding disc components towards the
mid-plane, with a resulting decrease in their vertical scaleheights. A
surprising result is the large radial distance of about 500 pc from the complex
centre over which the complex influences the disc. The complex has a comparable
effect on the vertical distribution of HI in the galactic disc. This `pinching'
or constraining effect should be detectable in the nearby spiral galaxies. Thus
the gravitational field of a complex results in local corrugations of the
stellar and HI vertical scaleheights, and the galactic disc potential is highly
non-uniform on scales of the inter-complex separation of about 1 kpc.


title: The stellar mass ratio of GK Persei

abstract:
  We study the absorption lines present in the spectra of the long-period
cataclysmic variable GK Per during its quiescent state, which are associated
with the secondary star. By comparing quiescent data with outburst spectra we
infer that the donor star appears identical during the two states and the inner
face of the secondary star is not noticeably irradiated by flux from the
accreting regions. We obtain new values for the radial velocity semi-amplitude
of the secondary star, Kk = 120.5 +- 0.7 km/s, a projected rotational velocity,
Vksin i = 61.5 +- 11.8 km/s and consequently a measurement of the stellar mass
ratio of GK Per, q = Mk/Mwd = 0.55 +- 0.21. The inferred white dwarf radial
velocities are greater than those measured traditionally using the wings of
Doppler-broadened emission lines suspected to originate in an accretion disk,
highlighting the unsuitability of emission lines for mass determinations in
cataclysmic variables. We determine mass limits for both components in the
binary, Mk >= 0.48 +- 0.32 Msolar and Mwd >= 0.87 +- 0.24 Msolar.


title:
Pair annihilation and radio emission from galactic jet sources: The case
  of Nova Muscae

abstract:
  In the hard X-ray spectra of some X-ray binaries line features at around 500
keV are detected. We interpret these as arising from pair annihilation in
relativistic outflows leading to a significant Doppler shift of the lines'
frequencies. We show how this can be used to accurately determine the bulk
velocity and orientation to the line of sight of the outflows. Constraints on
the energy requirements of such outflows are also derived. Furthermore, we show
that a small fraction of pairs escaping the annihilation region may give rise
to the radio synchrotron emission observed in some of these objects. We apply
these ideas to the hard X-ray and radio observations of Nova Muscae 1991. In
this object, the energy requirements seem to rule out a large proton fraction
in the outflows.


title: On the cosmological evolution of BL Lacs

abstract:
  We study the cosmological evolution of BL Lac objects by applying the Ve/Va
analysis to a new sample of 55 objects presented for the first time in this
paper. This sample has been selected from the 239 sources with the brightest
X-ray flux (>4X10^-13 erg s^-1 cm^-2) and relatively bright optical counterpart
(B<20.5) among the ~1600 objects included in the REX survey. The uniform
distribution of the Ve/Va values found in the sample suggests that BL Lac
objects are not affected by a strong cosmological evolution in contrast with
the behavior observed in the emission line AGNs. The Ve/Va analysis applied to
the subsample of the High energy peaked BL Lacs (HBL) does not reveal a
significant departure from a uniform distribution. This result suggests either
that the cosmological evolution is less extreme than that previously found in
other samples or that it is carried out only by a minority of objects, namely
by the most extreme HBLs.


title: Eternally accelerating universe without event horizon

abstract:
  Increasing astronomical evidence indicates that the expansion of the universe
is accelerating. By simply solving Einstein equations we show in this letter
that a wide class of generic quintessence models leading to eternal
acceleration is associated with spacetime static metrics which do not exhibit
future event horizons, and therefore do not pose the same problems for string
theory as asymptotic de Sitter space.


title:
Constraints on the equation of state of ultra-dense matter from
  observations of neutron stars

abstract:
  I discuss constraints on the equation of state of matter at supra-nuclear
densities that can be derived from observations of neutron stars. I focus on
recent work on Vela X-1, which may well be substantially more massive than the
canonical 1.4 solar masses, and on the prospects offered by the `isolated' or
`thermally-emitting' neutron stars. I present a re-analysis of the LETG
observations of the brightest of the isolated neutron stars, RX J1856.5-3754,
and find that the spectrum shows, unlike all other neutron stars observed so
far, a significant absorption feature, near 39 Angstrom.


title: Clustering in the Las Campanas Distant Cluster Survey

abstract:
  We utilize a sample of galaxy clusters at 0.35<z<0.6 drawn from the Las
Campanas Distant Cluster Survey (LCDCS) to provide the first non-local
constraint on the cluster-cluster spatial correlation function. The LCDCS
catalog, which covers an effective area of 69 square degrees, contains over
1000 cluster candidates. Estimates of the redshift and velocity dispersion
exist for all candidates, which enables construction of statistically
completed, volume-limited subsamples. In this analysis we measure the angular
correlation function for four such subsamples at z~0.5. After correcting for
contamination, we then derive spatial correlation lengths via Limber inversion.
We find that the resulting correlation lengths depend upon mass, as
parameterized by the mean cluster separation, in a manner that is consistent
with both local observations and CDM predictions for the clustering strength at
z=0.5.


title: An Unbiased Survey for Outflows in the W3 and W5 Star-Formation Regions

abstract:
  During their birth all stars undergo periods of copious mass loss, frequently
characterized by the occurrence of bipolar outflows. These outflows are
believed to play a fundamental role in the star formation process. However the
exact outflow generating method is obscure at present. To elucidate this
problem we are investigating whether the flow properties are correlated over
the entire protostellar mass spectrum. Progress in this area requires that we
assemble a statistically valid sample of high-mass outflow systems. This is
necessary since existing catalogues of such objects are heterogeneous and
statistically incomplete.


title: Jet reorientation in AGN: two winged radio galaxies

abstract:
  Winged, or X-shaped, radio sources form a small class of morphologically
peculiar extragalactic sources. We present multi-frequency radio observations
of two such sources. We derive maximum ages since any re-injection of fresh
particles of 34 and 17Myr for the wings of 3C223.1 and 3C403, respectively,
based on the lack of synchrotron and inverse Compton losses. On morphological
grounds we favour an explanation in terms of a fast realignment of the jet axis
which occurred within a few Myr. There is no evidence for merger activity, and
the host galaxies are found to reside in no more than poor cluster
environments. A number of puzzling questions remain about those sources: in
particular, although the black hole could realign on sufficiently short
timescales, the origin of the realignment is unknown.


title: 5-micron photometry of late-type dwarfs

abstract:
  We present narrowband-M photometry of nine low-mass dwarfs with spectral
types ranging from M2.5 to L0.5. Combining the (L'-M') colours derived from our
observations with data from the literature, we find colours consistent with a
Rayleigh-Jeans flux distribution for spectral types earlier than M5, but
enhanced F_3.8/F_4.7 flux ratios (negative (L'-M') colours) at later spectral
types. This probably reflects increased absorption at M' due to the CO
fundamental band. We compare our results against recent model predictions and
briefly discuss the implications.


title: Self consistent estimates of magnetic fields from reheating

abstract:
  We investigate the generation of primordial magnetic fields from stochastic
currents created by the cosmological transition from inflation to reheating. We
consider N charged scalar fields coupled to the electromagnetic field in a
curved background and derive self-consistent equations for the evolution of the
two point functions of the fields, which in the large N limit give a decoupled
set for the scalar and the electromagnetic functions. The main contribution to
the electric current comes from the infrared portion of the spectrum of created
particles, and in this limit the damping of the magnetic field is not due to
normal conductivity but to London currents in the scalar field. For a given set
of the physical parameters of the problem, we solved this equation numerically
and found that, due to the fact that the London currents are oscillating, the
field actually grows exponentially during the time interval in which our
large-N limit equations are valid. Although for the chosen parameters the
induced field is weak, the present uncertainties on their actual values leave
open the possibility for higher intensities.


title: Infrared Views of the TW Hya Disk

abstract:
  The face-on disk around TW Hya is imaged in scattered light at wavelengths of
1.1 and 1.6 micron using the coronagraph in the Near Infrared Camera and Multi
Object Spectrometer aboard the Hubble Space Telescope. Stellar light scattered
from the optically thick dust disk is seen from 20-230 AU. The surface
brightness declines as a power law of r^(-2.6+/-0.1) between 45 and 150 AU. The
scattering profile indicates that the disk is flared, not geometrically flat.
The disk, while spatially unresolved in thermal radiation at wavelengths of 12
and 18 micron in observations from the W. M. Keck Observatory, shows amorphous
and crystalline silicate emission in its spectrum. A disk with silicate grains
of a ~1 micron in size in its surface layers can explain the shape of the
mid-infrared spectrum. Much larger grains in the disk interior are necessary to
fit the millimeter-wave spectral energy distribution, and hence grain growth
from an original interstellar size population may have occurred.


title: Dubious Deductions from AGN Survey Data

abstract:
  The participants in this meeting are almost all carrying out the hard work of
making many different types of AGN surveys. Since it's so much easier to
criticize other people's work than to do actual work myself, I'll just present
some demurs regarding recent papers drawing conclusions from various AGN survey
data. In particular I'll mention some questionable interpretations of surveys
of Seyfert 2 near-UV polarization; interpreting the results of searches for
polarized broad H-alpha lines in Seyfert 2s; testing the beam model for radio
galaxies and quasars; testing the unification of Seyfert spectral types with a
torus; and finally testing the energy sources for Ulirgs, especially those with
Liner optical spectra. Only the polarized broad H-alpha results are examined in
detail here.


title: Early-type galaxies in the SDSS

abstract:
  A sample of nearly 9000 early-type galaxies, in the redshift range
0.01<z<0.3, was selected from the Sloan Digital Sky Survey using morphological
and spectral criteria. The sample was used to study how early-type galaxy
observables, including luminosity L, effective radius R, surface brightness I,
color, and velocity dispersion V, are correlated with one another. Measurement
biases are understood with mock catalogs which reproduce all of the observed
scaling relations. At any given redshift, the intrinsic distribution of
luminosities, sizes and velocity dispersions in our sample are all
approximately Gaussian. In the r* band L ~ V^3.91, L ~ R^1.58, R ~ I^(-0.75),
and the Fundamental Plane relation is R ~ V^(1.49) I^(-0.75). These relations
are approximately the same in the g*, i* and z* bands. At fixed luminosity, the
mass-to-light ratio scales as M/L ~ L^0.14. The g*-r* color scales as V^0.25.
Color also correlates with magnitude and size, but these correlations are
entirely due to the L-V and R-V relations. Chemical evolution and star
formation histories are investigated using co-added spectra of similar objects
in our sample. Chemical abundances correlate primarily with velocity
dispersion. At fixed V, the higher redshift population is bluer, is weaker in
Mg2, and is stronger in Hbeta than the population nearby. In addition, the
population at higher redshifts is slightly more luminous. These differences are
consistent with that of a passively evolving population which formed the bulk
of its stars about 9 Gyrs ago. The Fundamental Plane suggests that galaxies in
dense regions are slightly different from those in less dense regions, but the
co-added spectra and color--magnitude relations show no statistically
significant dependence on environment.


title: The ionising cluster of 30 Doradus.IV. Stellar kinematics

abstract:
  On the basis of multislit spectroscopy of 180 stars in the ionising cluster
of 30 Doradus we present reliable radial velocities for 55 stars. We calculate
a radial velocity dispersion of ~35 km/s for the cluster and we analyse the
possible influence of spectroscopic binaries in this rather large velocity
dispersion. We use numerical simulations to show that the observations are
consistent with the hypothesis that all the stars in the cluster are binaries,
and the total mass of the cluster is ~5E+5 solar masses. A simple test shows
only marginal evidence for dynamical mass segregation which if present is most
likely not due to dynamical relaxation.


title: Advanced Compton Telescope Designs and SN Science

abstract:
  The Advanced Compton Telescope (ACT) has been suggested to be the optimal
next-generation instrument to study nuclear gamma-ray lines. In this work, we
investigate the potential of three hypothetical designs of the ACT to perform
SN science. We provide estimates of 1) the SN detection rate, 2) the SN Ia
discrimination rate, and 3) which gamma-ray lines would be detected from
specific supernova remnants. We find that the prompt emission from a SN Ia is
such that it is unlikely that one would be within the range that an
INTERMEDIATE ACT would be able to distinguish between explosion scenarios,
although such an instrument would detect a handful of SNRs.
  We further find that the SUPERIOR ACT design would be a truly breakthrough
instrument for SN science. By supplying these estimates, we intend to assist
the gamma-ray astrophysics community in deciding the course of the next decade
of gamma-ray SN science.


title: High-Resolution Mid-Infrared Morphology of Cygnus A

abstract:
  We present subarcsecond resolution mid-infrared images at 10.8 and 18.2
microns of Cygnus A. These images were obtained with the University of Florida
mid-IR camera/spectrometer OSCIR at the Keck II 10-m telescope. Our data show
extended mid-IR emission primarily to the east of the nucleus with a possible
western extension detected after image deconvolution. This extended emission is
closely aligned with the bi-conical structure observed at optical and near-IR
wavelengths by the HST. This emission is consistent with dust heated from the
central engine of Cygnus A. We also marginally detect large-scale low level
emission extending > 1.5 kpc from the nucleus which may be caused by in-situ
star formation, line emission, and/or PAH contamination within the bandpass of
our wide N-band filter.


title: Cosmic Structure Formation with Topological Defects

abstract:
  Topological defects are ubiquitous in physics. Whenever a symmetry breaking
phase transition occurs, topological defects may form. The best known examples
are vortex lines in type II super conductors or in liquid Helium, and
declination lines in liquid crystals. In an adiabatically expanding universe
which cools down from a very hot initial state, it is quite natural to
postulate that topological defects may have emerged during a phase transition
in the early universe and that they may have played the role of initial
inhomogeneities seeding the formation of cosmic structure. This basic idea goes
back to Kibble (1976). In this report we summarize the progress made in the
investigation of Kibble's idea during the last 25 years. Our understanding of
the formation and evolution of topological defects is reported almost
completely in the beautiful book by Vilenkin & Shellard or the excellent Review
by Hindmarsh & Kibble, and we shall hence be rather short on that topic.
Nevertheless, in order to be self contained, we have included a short chapter
on spontaneous symmetry breaking and defect formation. Our main topic is
however the calculation of structure formation with defects, results which are
not included in the above references.


title: New physics and astronomy with the new gravitational-wave observatories

abstract:
  Gravitational-wave detectors with sensitivities sufficient to measure the
radiation from astrophysical sources are rapidly coming into existence. By the
end of this decade, there will exist several ground-based instruments in North
America, Europe, and Japan, and the joint American-European space-based antenna
LISA should be either approaching orbit or in final commissioning in
preparation for launch. The goal of these instruments will be to open the field
of gravitational-wave astronomy: using gravitational radiation as an
observational window on astrophysics and the universe. In this article, we
summarize the current status of the various detectors currently being
developed, as well as future plans. We also discuss the scientific reach of
these instruments, outlining what gravitational-wave astronomy is likely to
teach us about the universe.


title: The UCSD HIRES/KeckI Damped Lya Abundance Database: I. The Data

abstract:
  We present new chemical abundance measurements of 16 damped Lya systems at
z>1.5 and update our previous abundance analyses. The entire database presented
here was derived from HIRES observations on the Keck I telescope, reduced with
the same software package, and analysed with identical techniques. Altogether,
we present a large, homogeneous database of chemical abundance measurements for
protogalaxies in the early universe, ideal for studying a number of important
aspects of galaxy formation. In addition, we have established an online
directory for this database and will continuously update the results.


title: The UCSD HIRES/KeckI Damped Lya Abundance Database: II. The Implications

abstract:
  We present a comprehensive analysis of the damped Lya abundance database
presented in the first paper of this series. This database provides a
homogeneous set of abundance measurements for many elements including Si, Cr,
Ni, Zn, Fe, Al, S, Co, O, and Ar from 38 damped Lya systems with z > 1.5. With
little exception, these damped Llya systems exhibit very similar relative
abundances. There is no significant correlation in X/Fe with [Fe/H] metallicity
and the dispersion in X/Fe is small at all metallicity.
  We search the database for trends indicative of dust depletion and in a few
cases find strong evidence. Specifically, we identify a correlation between
[Si/Ti] and [Zn/Fe] which is unambiguous evidence for depletion.
  We present a discussion on the nucleosynthetic history of the damped Lya
systems by focusing on abundance patterns which are minimally affected by dust
depletion. We find [Si/Fe] -> +0.25 dex as [Zn/Fe] -> 0 and that the [Si/Fe]
values exhibit a plateau of ~+0.3 dex at [Si/H] < -1.5 dex. Together these
trends indicate significant alpha-enrichment in the damped Lya systems at low
metallicity, an interpretation further supported by the observed O/Fe, S/Fe and
Ar/Fe ratios. We also discuss Fe-peak nucleosynthesis and the odd-even effect.
  To assess the impact of dust obscuration, we present estimates of the
dust-to-gas ratios for the damped Lya sightlines and crudely calculate dust
extinction corrections. The distribution of extinction corrections suggests the
effects of dust obscuration are minimal and that the population of 'missing'
damped systems has physical characteristics similar to the observed sample.
  We update our investigation on the chemical evolution of the early universe
in neutral gas. [significantly abridged]


title: The $\alpha$ Dynamo Effects in Laboratory Plasmas

abstract:
  A concise review of observations of the $\alpha$ dynamo effect in laboratory
plasmas is given. Unlike many astrophysical systems, the laboratory pinch
plasmas are driven magnetically. When the system is overdriven, the resultant
instabilities cause magnetic and flow fields to fluctuate, and their
correlation induces electromotive forces along the mean magnetic field. This
$\alpha$-effect drives mean parallel electric current, which, in turn, modifies
the initial background mean magnetic structure towards the stable regime. This
drive-and-relax cycle, or the so-called self-organization process, happens in
magnetized plasmas in a time scale much shorter than resistive diffusion time,
thus it is a fast and unquenched dynamo process. The observed $\alpha$-effect
redistributes magnetic helicity (a measure of twistedness and knottedness of
magnetic field lines) but conserves its total value. It can be shown that fast
and unquenched dynamos are natural consequences of a driven system where
fluctuations are statistically either not stationary in time or not homogeneous
in space, or both. Implications to astrophysical phenomena will be discussed.


title: Constraining dark energy with Sunyaev-Zel'dovich cluster surveys

abstract:
  We discuss the prospects of constraining the properties of a dark energy
component, with particular reference to a time varying equation of state, using
future cluster surveys selected by their Sunyaev-Zel'dovich effect. We compute
the number of clusters expected for a given set of cosmological parameters and
propogate the errors expected from a variety of surveys. In the short term they
will constrain dark energy in conjunction with future observations of type Ia
supernovae, but may in time do so in their own right.


title:
The Transformation of Galaxies within the Large Scale Structure around a
  z=0.41 Cluster

abstract:
  We present deep, panoramic multi-color imaging of the distant rich cluster
A851 (Cl0939+4713, z=0.41) using Suprime-Cam on Subaru. These images cover a
27' field of view, ~11 Mpc at z=0.41, and by exploiting photometric redshifts
estimated from our BVRI imaging we can isolate galaxies in a narrow redshift
slice at the cluster redshift. Using a sample of ~2700 probable cluster members
brighter than 0.02 Lv*, we trace the network of filaments and subclumps around
the cluster core. The depth of our observations, combined with the
identification of filamentary structure, gives us an unprecedented opportunity
to test the influence of the environment on the properties of low luminosity
galaxies. We find an abrupt change in the colors of < 0.1 Lv* galaxies at a
local density of 100 gal. per sq. Mpc, with the population in lower density
regions being predominantly blue, while those in higher density regions are
red. The transition in the color-local density behavior occurs at densities
corresponding to subclumps within the filaments surrounding the cluster.
Identifying the sites where the transition occurs brings us much closer to
understanding the mechanisms which are responsible for establishing the
present-day relationship between environment and galaxy characteristics.


title:
On the Origin of Lyman$\alpha$ Blobs at High Redshift: Submillimetric
  Evidence for a Hyperwind Galaxy at z=3.1

abstract:
  The most remarkable class of high-redshift objects observed so far is
extended Ly$\alpha$ emission-line blobs found in an over-density region at
redshift 3.1. They may be either a dust-enshrouded, extreme starburst galaxy
with a large-scale galactic outflow (superwind) or cooling radiation from dark
matter halos. Recently one of these Ly$\alpha$ blobs has been detected at
submillimeter wavelengths (450 and 850 $\mu$m). Here we show that its
rest-frame spectral energy distribution between optical and far-infrared is
quite similar to that of Arp 220, which is a typical ultraluminous
starburst/superwind galaxy in the local universe. This suggests strongly that
the superwind model proposed by Taniguchi & Shioya is applicable to this
Ly$\alpha$ blob. Since the blob is more luminous in the infrared by a factor of
30 than Arp 220, it comprises a new population of hyperwind galaxies at high
redshift.


title: New light on the search for low metallicity galaxies I. The N2 method

abstract:
  We present a simple metallicity estimator based on the logarithmic [NII]6584
/ Halpha ratio, hereafter N2, which we envisage will become very useful for
ranking galaxies in a metallicity sequence from redshift survey quality data
even for moderately low spectral resolution. We have calibrated the N2
estimator using a compilation of HII galaxies having accurate oxygen
abundances, plus photoionization models covering a wide range of abundances.
The comparison of models and observations indicates that both primary and
secondary nitrogen are important for the relevant range of metallicities. The
N2 estimator follows a linear relation with log(O/H) that holds for the whole
abundance range covered by the sample, from about 1/50th to twice the Solar
value (7.2 < 12+log(O/H) < 9.1). We suggest that the ([SII]6717,6731 / Halpha)
ratio (hereafter S2) can also be used as a rough metallicity indicator. Because
of its large scatter the S2 estimator will be useful only in systems with very
low metallicity, where [NII]6584 is not detected or in low resolution spectra
where [NII]6584 is blended with Halpha.


title: Infrared Views of Galaxy Evolution: A Progress Report

abstract:
  The two major functions in galaxy evolution that we would like to measure are
the stellar populations in galaxies, and their time-derivative, the star
formation rate. Especially at redshifts above 1, both of these measures are
benefiting greatly from wide-area infrared data. To date, most of these
infrared observations suggest that a significant fraction of the star formation
suffers substantial internal extinction from dust. Ground-based illustrations
include optical/infrared photometric redshift estimates of Balmer-break
galaxies, and near-infrared narrow-band imaging and spectroscopy of emission
lines redshifted from the optical rest frame. Space-based examples include
slitless spectroscopic surveys for H-alpha line emission, mid- and far-infrared
diffuse background measurements and deep number counts, and searches for
starlight from damped Lyman-alpha absorbers.


title: FUSE Observations towards HD 34078 Detection of highly excited H2 and HD

abstract:
  We present FUSE observations of the extincted O9.5 star, HD 34078. The 19
first levels of H2 are detected (i.e. from J=0 to v=1, J=5) as well as HD in
its two first levels. The excitation of H2 up to J=7 can be explained using a
combination of Photon Dominated Region (PDR) and MHD shock models. However,
understanding the large amount of H2 found in higher excitation states seems to
require more energetic processes that have yet to be identified.


title:
A simple analytical model for the abundance of damped Ly-\alpha
  absorbers

abstract:
  A simple analytical model for estimating the fraction (\Omega_{gas}) of
matter in gaseous form within the collapsed dark matter (DM) haloes is
presented. The model is developed using (i) the Press-Schechter formalism to
estimate the fraction of baryons in DM haloes, and (ii) the observational
estimates of the star formation rate at different redshifts. The prediction for
\Omega_{gas} from the model is in broad agreement with the observed abundance
of the damped Ly-\alpha systems. Furthermore, it can be used for estimating the
circular velocities of the collapsed haloes at different redshifts, which could
be compared with future observations.


title: Cepheids as Distance Indicators: Some Current Problems

abstract:
  A general review is given of the calibration of the Cepheid distance scale,
with particular reference to its use in the determination of H0. Emphasis is
placed on the advantage of using a galactic calibration of the Cepheid scale,
rather than relying on an adopted distance to the LMC. It is then possible to
use LMC data to test for possible metallicity effects on this scale.


title:
The subsurface radial gradient of solar angular velocity from MDI f-mode
  observations

abstract:
  We report quantitative analysis of the radial gradient of solar angular
velocity at depths down to about 15 Mm below the solar surface for latitudes up
to 75 degree using the Michelson Doppler Imager (MDI) observations of surface
gravity waves (f modes) from the Solar and Heliospheric Observatory (SoHO). A
negative outward gradient of around -400 nHz/R, equivalent to logarithmic
gradient of the rotation frequency with respect to radius which is very close
to -1, is found to be remarkably constant between the equator and 30 degree of
latitude. Above 30 degree it decreases in absolute magnitude to a very small
value at around 50 degree. At higher latitudes the gradient may reverse its
sign: if so this reversal takes place in a thin layer extending only 5 Mm
beneath the visible surface, as evidenced by the most superficial modes (with
degrees l>250). The signature of the torsional oscillations is seen in this
layer, but no other significant temporal variations of the gradient and value
of the rotation rate there are found.


title: Does MOND follow from the CDM paradigm?

abstract:
  In a recent paper, Kaplinghat and Turner (2001) (KT) advertise that MOND can
be derived naturally in the CDM paradigm. They actually proceed to produce a
more limited result: Every galaxy should have a transition radius, $r_t$, below
which baryons dominate, and above which dark matter (DM) takes over; the
acceleration at $r_t$ is nearly the same for all galaxies; and due to a
coincidences this is of order $a_0\sim cH_0$. This follows from their tacit,
intermediate result, whereby CDM halos of galaxies have a very nearly universal
acceleration profile $a(r)\approx v^2(r)/r\approx A\hat a(r/\ell)$, where A is
universal, and only the scale $\ell$ varies from halo to halo. (This remains so
when baryons are added because they assume a universal baryon-collapse factor.)
The KT scenario is phenomenologically wrong--observed galaxies are simply not
like that. For example, it precludes altogether the existence of LSB galaxies,
in which the acceleration is everywhere smaller than $a_0$. The
phenomenologically sound outcome--i.e., the role of $a_0$ as a transition
acceleration in high-surface-brightness galaxies--pertains to only a small part
of the statement of MOND. There are several other, independent roles that
$a_0\sim cH_0$ plays in MOND phenomenology, and other predictions of MOND, not
related to the value of $a_0$, that are not explainable in the KT scenario.
  The results of KT also disagree with those of CDM simulations, which, as they
now stand, do not reproduce any aspect of MOND phenomenology.


title: High-Mass Proto-Stellar Candidates - I : The Sample and Initial Results

abstract:
  We describe a systematic program aimed at identifying and characterizing
candidate high-mass proto-stellar objects (HMPOs). Our candidate sample
consists of 69 objects selected by criteria based on those established by
Ramesh & Sridharan (1997) using far-infrared, radio-continuum and molecular
line data. Infrared-Astronomical-Satellite (IRAS) and
Midcourse-Space-Experiment (MSX) data were used to study the larger scale
environments of the candidate sources and to determine their total luminosities
and dust temperatures. To derive the physical and chemical properties of our
target regions, we observed continuum and spectral line radiation at millimeter
and radio wavelengths. We imaged the free-free and dust continuum emission at
wavelengths of 3.6 cm and 1.2 mm, respectively, searched for H2O and CH3OH
maser emission and observed the CO 2-1 and several NH3 lines toward all sources
in our sample. Other molecular tracers were observed in a subsample. The
presented results indicate that a substantial fraction of our sample harbors
HMPOs in a pre-UCHII region phase, the earliest known stage in the high-mass
star formation process.


title:
Analysis of the solar cycle and core rotation using 15 years of Mark-I
  observations:1984-1999. I. The solar cycle

abstract:
  High quality observations of the low-degree acoustic modes (p-modes) exist
for almost two complete solar cycles using the solar spectrophotometer Mark-I,
located at the Observatorio del Teide (Tenerife, Spain) and operating now as
part of the Birmingham Solar Oscillations Network (BiSON). We have performed a
Fourier analysis of 30 calibrated time-series of one year duration covering a
total period of 15 years between 1984 and 1999. Applying different techniques
to the resulting power spectra, we study the signature of the solar activity
changes on the low-degree p-modes. We show that the variation of the central
frequencies and the total velocity power (TVP) changes. A new method of
simultaneous fit is developed and a special effort has been made to study the
frequency-dependence of the frequency shift. The results confirm a variation of
the central frequencies of acoustic modes of about 450 nHz, peak-to-peak, on
average for low degree modes between 2.5 and 3.7 mHz. The TVP is
anti-correlated with the common activity indices with a decrease of about 20%
between the minimum and the maximum of solar cycle 22. The results are compared
with those obtained for intermediate degrees, using the LOWL data. The
frequency shift is found to increase with the degree with a weak l-dependence
similar to that of the inverse mode mass. This verifies earlier suggestions
that near surface effects are predominant.


title: Discovery of 5.16s pulsations from the isolated neutron star RBS 1223

abstract:
  The isolated neutron star candidate RBS 1223 was observed with the Advanced
CCD Imaging Spectrometer aboard the Chandra X-ray observatory on 2000 June 24.
A timing analysis of the data yielded a periodic modulation with a period
P=5.1571696^(+1.57*10^(-4) -1.36*10^(-4)s. Using ROSAT HRI archived
observations we detected a period P=5.1561274 \pm 4.4*10^(-4)s and determined
period derivative dP/dt=(0.7 - 2.0)*10^(-11) s*s^(-1). The detection of this
period and dP/dt indicates that RBS 12223 has a ``characteristic'' age of
6000-12000 years and huge magnetic field at the surface (B(dipole)~(1.7-
3.2)*10^(+14) G) typical for anomalous X-ray pulsars (AXPs).


title:
The Excitation and Metallicity of Galactic HII Regions from ISO-SWS
  Observations of Mid-Infrared Fine-Structure Lines

abstract:
  We present mid-infrared ISO-SWS observations of the fine-structure emissions
lines [NeII]12.8, [NeIII]15.6, [NeIII]36, [ArII]6.9, [ArIII]8.9, [SIII]18.7,
[SIII]33.5, [SIV]10.5, and the recombination lines Br_alpha and Br_beta, in a
sample of 112 Galactic HII regions and 37 nearby extra-galactic HII regions in
the LMC, SMC, and M33. The Galactic sources have a wide range in galactocentric
distance (0<R<18kpc), which enables us to study excitation and metallicity
variations over large Galactic scales. We detect a steep rise in the
[NeIII]15.6/[NeII]12.8,[ArIII]8.9/[ArII]6.9, and [SIV]10.5/[SIII]33.5
excitation ratios from the inner Galaxy outwards, and a moderate decrease in
metallicity, from twice solar in the inner Galaxy to solar in the outer disk.
The extra galactic sources in our sample show low gas density, low metallicity
and high excitation. We find a good correlation between the neon and the argon
excitation ratios in our sample. The observed correlation is well-reproduced by
theoretical nebular models which incorporate new generation wind-driven NLTE
model stellar atmospheres for the photoionizing stars. In particular, the NLTE
atmospheres can account for the production of [NeIII] emission in the HII
regions. We conclude that the increase in nebular excitation with
galactocentric radius is due to an increase in stellar effective temperature
(as opposed to a hardening of the stellar SEDs due to the metallicity
gradient). The good fit between observations and our models support the
conclusion of Thornley et al. (2000), that the low neon ratios observed in
extra-galactic sources are due to global aging effects.


title:
XMM-Newton discovery of a sharp spectral feature at ~7 keV in the
  Narrow-Line Seyfert 1 galaxy 1H 0707-495

abstract:
  We report the first detection of a sharp spectral feature in a Narrow-Line
Seyfert 1 galaxy. Using XMM-Newton we have observed 1H0707-495 and find a drop
in flux by a factor of more than 2 at a rest-frame energy of ~7 keV without any
detectable narrow Fe K alpha line emission. The energy of this feature suggests
a connection with the neutral iron K photoelectric edge, but the lack of any
obvious absorption in the spectrum at lower energies makes the interpretation
challenging. We explore two alternative explanations for this unusual spectral
feature: (i) partial covering absorption by clouds of neutral material and (ii)
ionised disc reflection with lines and edges from different ionisation stages
of iron blurred together by relativistic effects. We note that both models
require an iron overabundance to explain the depth of the feature. The X-ray
light curve shows strong and rapid variability, changing by a factor of four
during the observation. The source displays modest spectral variability which
is uncorrelated with flux.


title: Spiral arms, bar shape and bulge microlensing in the Milky Way

abstract:
  A new model for the luminosity distribution in the inner Milky Way is found,
using a non-parametric penalized maximum-likelihood algorithm to deproject a
dereddened COBE/DIRBE L-band map of the inner Galaxy. The model is also
constrained by the apparent magnitude (line-of-sight) distributions of clump
giant stars in certain bulge fields. An important new feature is the inclusion
of a spiral arm model in the disk. Spiral arms make the model appear broader on
the sky, thus our bar is more elongated than in previous eight-fold symmetric
models. They also lead to a smoother disk model interior to the Sun. The bar
length is approx. 3.5kpc and its axis ratios are 1:(0.3-0.4):0.3, independent
of whether the spiral arm model is 4-armed or 2-armed. The larger elongation in
the plane makes it possible to reproduce the observed clump giant distributions
as well. For the bar angle we estimate 15^o <= phi <= 30^o, with the best
models obtained for 20^o <= phi <= 25^o. We use our reference model to predict
a microlensing optical depth map towards the bulge, normalising its mass by the
observed terminal velocity curve. For clump giant sources at (l,b)=(3.9,-3.8)
we find tau_{-6}:=tau/10^{-6}=1.27, within 1.8*sigma of the new MACHO
measurement given by Popowski et al. The value for all sources at
(l,b)=(2.68,-3.35) is tau_{-6}=1.1, still >3*sigma away from the published
MACHO DIA value. The dispersion of these tau_{-6} values within our models is
10%. Because the distribution of sources is well-fit by the NIR model,
increasing the predicted optical depths by >20% will be difficult. Thus the
high value of the measured clump giant optical depth argues for a near-maximal
disk in the Milky Way. (abridged)


title:
A new, kinematically anomalous HI component in the spiral galaxy NGC
  2403

abstract:
  We discuss new, high sensitivity HI observations of the spiral galaxy NGC2403
which show extended emission at anomalous velocities with respect to the `cold'
disk. This `anomalous' gas component (~1/10 of the total HI mass) is probably
located in the region of the halo and rotates more slowly (~20-50 km/s) than
the gas in the disk. Moreover, it shows a distortion in the velocity field that
we interpret as a large-scale radial motion (10-20 km/s inflow) towards the
centre of the galaxy. The most likely explanation for its origin and kinematics
seems to be that of a galactic fountain. There is, however, a significant part
of the anomalous gas which seems to be moving contrary to rotation and is
difficult to understand in such a picture. These anomalous gas complexes
discovered in NGC 2403 may be analogous to the High Velocity Clouds of our
Galaxy. They may be rather common in spiral galaxies and not have been detected
yet for lack of sensitivity.


title:
High-Mass Proto-Stellar Candidates - II : Density structure from dust
  continuum and CS emission

abstract:
  We present a detailed 1.2 mm continuum and CS spectral line study of a large
sample of 69 massive star forming regions in very early stages of evolution,
most of them prior to building up an ultracompact HII region. The continuum
data show a zoo of different morphologies and give detailed information on the
spatial distributions, the masses, column densities and average densities of
the whole sample. Fitting the radial intensity profiles shows that three
parameters are needed to describe the spatial distribution of the sources:
constant emission from the center out to a few arcsec radius followed by a
first power law intensity distribution which steepens further outside into a
second power law distribution. The mean inner power law intensity index mi
(I~r^(-mi)) is 1.2 corresponding to density indices p (n~r^(-p)) of 1.6. In
total the density distribution of our massive star formations sites seem to be
not too different from their low-mass counterparts, but we show that setting
tight constrains on the density indices is very difficult and subject to many
possible errors. The local densities we derive from CS calculations are higher
(up to one order of magnitude) than the mean densities we find via the
mm-continuum. Such inhomogeneous density distribution reflects most likely the
ubiquitous phenomenon of clumping and fragmentation in molecular clouds.
Linewidth-mass relations show a departure from virial equilibrium in the stages
of strongly collapsing cores.


title:
On the Radial Structure of Radiatively Inefficient Accretion Flows with
  Convection

abstract:
  We consider the radial structure of radiatively inefficient hydrodynamic
accretion flows around black holes. We show that low-viscosity flows consist of
two zones: an outer convection-dominated zone and an inner advection-dominated
zone. The transition between these two zones occurs at ~50 Schwarzschild radii.


title: Massive molecular outflows

abstract:
  Well established correlations of low-mass flows show a continuity in the
high-mass regime, and mean accretion rates for L>1000 Lsun are dM/dt~10^(-4)
Msun/yr. We also present a tight correlation between outflow masses and core
masses, which implies that the accretion rate is to first order a linear
function of the core mass. All those results support the idea that similar
physical processes drive outflows of all masses.


title: Schwarzschild metrics, quasi-universes and wormholes

abstract:
  We introduce the concept of "quasi-universe" and describe the Einstein-Rosen
bridge as an extreme wormhole connecting two quasi-universes.


title: Gas Dynamics and Inflow in gas-rich Galaxy Mergers

abstract:
  We performed N-body/SPH simulations of merging gas-rich disk galaxies with
mass ratios of 1:1 and 3:1. A stellar disk and bulge component and a dark halo
was realized with collisionless particles, the gas was represented by SPH
particles. Since we did not include star formation we focused on the gas
dynamics and its influence on the structure of merger remnants. We find that
equal-mass mergers are in general more effective in driving gas to the center.
Around 50% of the gas resides in the central regions after the merger is
complete. The gas in unequal-mass mergers keeps a large amount of its initial
angular momentum and settles in a large scale disk while only 20% -30% of the
gas is driven to the center. This general result is almost independent of the
merger geometry. The gas in the outer regions accumulates in dense knots within
tidal tails which could lead to the formation of open clusters or dwarf
satellites. Later on, the gas knots loose angular momentum by dynamical
friction and successively sink to the center of the remnant thereby increasing
the total gas content of the disk. Due to the influence of the gas the
simulated merger remnant becomes more oblate than its pure stellar counterpart.
The shape of the stellar LOSVD changes and the third-order Gauss-Hermite
coefficient $h_3$ is in good agreement with observations.


title:
Automatic variability analysis of bulge stars in OGLE II image
  subtraction database

abstract:
  We present results of star variability analysis in OGLE II first bulge field.
Photometric database was derived by means of image subtraction method (Wozniak
2000) and contains 4597 objects pre-classified as variables. We analyzed all
the light curves in order to find periodic variables, non periodic but all-time
variables and stars showing episodic changes in their brightness, e.g.
gravitational lenses. Variability of 3969 stars was confirmed, among them we
detected 12 lensing event candidates whose light curves are shown. We found 762
periodic variables. Algorithmic methods let us identify 71 RR Lyrae and 110 W
UMa stars. Almost all luminous red giants are found to be variable. Most of red
clump giants are not variable. Classification of all 4597 objects is presented
online.


title:
Investigating the nature of the z~2.8 submillimeter selected galaxy SMM
  J02399-0136 with VLT spectropolarimetry

abstract:
  We present deep optical spectropolarimety of SMM J02399-0136 (z=2.8) done
with the VLT Antu 8.2 m telescope equipped with FORS1. Moderate continuum and
emission line polarization are measured (P~5%). We do not detect broad lines in
scattered flux as would be expected for a type-2 object but rather a
polarization behaviour similar to BAL quasars. This classification is confirmed
by the detection of both high and low ionization broad absorption troughs and a
very red continuum. We argue that this object shares several properties with
local ULIGs such as Mrk 231 and other ultraluminous infrared Lo-BAL quasars.
However, the fact that the ultraviolet spectrum is dominated by non-stellar
radiation does not prove that the dust that is thermally radiating in the far
infrared is predominantly heated by the AGN. Since the energy that we get in
the far-infrared is precisely that which is removed from the ultraviolet
spectrum, this could mean that the starburst is more dust-enshrouded than the
AGN due to a peculiar dust distribution. The limits we place on the putative
starburst contribution to the restframe ultraviolet continuum together with
constraints on the amount of extinction provides an upper limit to the star
formation rate of about 2000 Msun/yr, consistent with previously claimed high
star formation rate in this object.


title: Interstellar Abundances in the Magellanic Clouds

abstract:
  We summarize recent studies of the predominantly neutral gas in the
Magellanic Clouds (MC), based on combinations of high-resolution optical
spectra and UV spectra obtained with IUE, HST, and FUSE. Similarities in
relative gas-phase abundances for Galactic and MC sightlines with relatively
low N(H) had suggested that the depletion patterns might be similar in the
three galaxies -- at least where the depletions are relatively mild. New STIS
spectra of one higher N(H) SMC sightline, however, have revealed significant
differences, relative to the Galactic patterns, for SMC clouds characterized by
more severe depletions.


title: Ten Low Mass Companions from the Keck Precision Velocity Survey

abstract:
  Ten new low mass companions have emerged from the Keck precision Doppler
velocity survey, with minimum (msini) masses ranging from 0.8 mjup to 0.34
msun. Five of these are planet candidates with msini < 12 mjup, two are brown
dwarf candidates with msini ~30 mjup, and three are low mass stellar
companions. Hipparcos astrometry reveals the orbital inclinations and masses
for three of the (more massive) companions, and it provides upper limits to the
masses for the rest. A new class of extrasolar planet is emerging,
characterized by nearly circular orbits and orbital radii greater than 1 AU.
The planet HD 4208b appears to be a member of this new class. The mass
distribution of extrasolar planets continues to exhibit a rapid rise from 10
mjup toward the lowest detectable masses near 1 msat.


title:
External Compton emission from relativistic jets in Galactic black hole
  candidates and ultraluminous X-ray sources

abstract:
  Galactic binary systems that contain a black hole candidate emit hard X-rays
in their low luminosity mode. We show that this emission can be understood as
due to the Compton scattering of photons from the companion star and/or the
accretion disk by relativistic electrons in a jet. The same electrons are also
responsible for the radio emission. Two sources -- XTE J1118+480 and Cygnus X-1
-- are modelled as representatives of black holes with low and high luminosity
companion stars respectively. We further show that the ultraluminous compact
X-ray sources observed in nearby galaxies have the properties expected of
stellar mass black holes with high luminosity companions in which the jet is
oriented close to our line of sight.


title: Limits to Interstellar C_4 and C_5 Towards zeta Ophiuchi

abstract:
  We have made a sensitive search for the origin bands in the known electronic
transitions of the linear carbon chains C_4 and C_5 at 3789 and 5109 A towards
zeta Oph (A_V <= 1). The incentive was a recent detection of C_3 in this
interstellar cloud with a column density of 1.6 x 10^12 cm^-2 plus the
availability of laboratory gas phase spectra of C_4 and C_5. Further, some
models of diffuse interstellar clouds predict that the abundance of these
latter species should be within an order of magnitude of C_3. Despite achieving
S/N of 2300 to 2600 per pixel at a resolution of ~110,000, the searches were
negative, leading to 3 sigma upper limits to the column density of N(C_5) = 2 x
10^11 cm^-2 and N(C_4) = 4 x 10^12-13 cm^-2 where these values rely on
theoretically calculated oscillator strengths. The implication of these limits
are discussed on the choice of molecules for study in future attempts to
identify the carriers of the stronger diffuse interstellar bands.


title: J06587-5558 -- A Very Unusual Polarised Radio Source

abstract:
  We have found a peculiar radio source in the field of one of the hottest
known clusters of galaxies 1E0657-56. It is slightly extended, highly polarised
(54% at 8.8GHz) and has a very steep spectrum, with alpha ~ -1 at 1.3 GHz,
steepening to ~ -1.5 at 8.8GHz (S \propto nu^alpha). No extragalactic sources
are known with such high integrated polarisation, and sources with spectra as
steep as this are rare. In this paper, we report the unusual properties of the
source J06587-5558 and speculate on its origin and optical identification.


title:
Abundances of Recently Discovered Planetary Nebulae Towards the Galactic
  Bulge

abstract:
  In this work we report spectrophotometric observations of a planetary nebula
sample towards the galactic bulge. A total of 45 PNe was observed and their
physical parameters (electron density and temperature) were derived. Ionic
abundances were calculated using a three-level atom model and abundances were
derived through ionisation correction factors. Results show low abundance
objects at high galactic latitudes, indicating a possible vertical gradient
inside the bulge. A few objects with low N/O ratio were found, which could
originated from old, low mass progenitors.