title:
The Wide-Field Imaging Interferometry Testbed I: Purpose, Testbed
  Design, Data, and Synthesis Algorithms

abstract:
  The Wide-field Imaging Interferometry Testbed (WIIT) was designed to
validate, experiment with, and refine the technique of wide field mosaic
imaging for optical/IR interferometers. Here we offer motivation for WIIT,
present the testbed design, and describe algorithms that can be used to reduce
the data from a spatial and spectral Michelson interferometer. A conventional
single-detector Michelson interferometer operating with narrow bandwidth at
center wavelength lambda is limited in its field of view to the primary beam of
the individual telescope apertures, or ~lambda/d radians, where d is the
telescope diameter. Such a field is too small for many applications; often one
wishes to image extended sources. We are developing and testing techniques
analogous to the mosaicing method employed in millimeter and radio astronomy,
but applicable to optical/IR Michelson interferometers, in which beam
combination is done in the pupil plane. An Npix x Npix array detector placed in
the image plane of the interferometer is used to record simultaneously the
fringe patterns from many contiguous telescope fields, effectively multiplying
the field size by Npix/2, where the factor 2 allows for Nyquist sampling. This
technique will be especially valuable for interferometric space observatories,
such as the Space Infrared Interferometric Telescope (SPIRIT) and the
Submillimeter Probe of the Evolution of Cosmic Structure (SPECS). SPIRIT and
SPECS will be designed to provide sensitive, high angular resolution,
far-IR/submillimeter observations of fields several arcminutes in diameter, and
views of the universe complementary to those provided by the Hubble Space
Telescope (HST), the Next-Generation Space Telescope (NGST), and the Atacama
Large Millimeter Array (ALMA).


title: Dynamical Habitability of Known Extrasolar Planetary Systems

abstract:
  Habitability is usually defined as the requirement for a terrestrial planet's
atmosphere to sustain liquid water. This definition can be complemented by the
dynamical requirement that other planets in the system do not gravitationally
perturb terrestrial planets outside of their habitable zone, the orbital region
allowing the existence of liquid water. We quantify the dynamical habitability
of 85 known extrasolar planetary systems via simulations of their orbital
dynamics in the presence of potentially habitable terrestrial planets. When
requiring that habitable planets remain strictly within their habitable zone at
all time, the perturbing influence of giant planets extends beyond the
traditional Hill sphere for close encounters: terrestrial planet excursions
outside of the habitable zone are also caused by secular eccentricity
variations and, in some cases, strong mean-motion resonances. Our results
indicate that more than half the known extrasolar planetary systems (mostly
those with distant, eccentric giant planets) are unlikely to harbor habitable
terrestrial planets. About 1/4 of the systems (mostly those with close-in giant
planets), including 1/3 of the potential targets for the Terrestrial Planet
Finder, appear as dynamically habitable as our own Solar System. The influence
of yet undetected giant planets in these systems could compromise their
dynamical habitability. Some habitable terrestrial planets in our simulations
have substantial eccentricities (e > 0.1) which may lead to large seasonal
climate variations and thus affect their habitability.


title: The Cosmic Microwave Background & Inflation, Then & Now

abstract:
  Boomerang, Maxima, DASI, CBI and VSA significantly increase the case for
accelerated expansion in the early universe (the inflationary paradigm) and at
the current epoch (dark energy dominance), especially when combined with data
on high redshift supernovae (SN1) and large scale structure (LSS). There are
``7 pillars of Inflation'' that can be shown with the CMB probe, and at least
5, and possibly 6, of these have already been demonstrated in the CMB data: (1)
a large scale gravitational potential; (2) acoustic peaks/dips; (3) damping due
to shear viscosity; (4) a Gaussian (maximally random) distribution; (5)
secondary anisotropies; (6) polarization. A 7th pillar, anisotropies induced by
gravity wave quantum noise, could be too small. A minimal inflation parameter
set, \omega_b,\omega_{cdm}, \Omega_{tot}, \Omega_Q,w_Q,n_s,\tau_C, \sigma_8},
is used to illustrate the power of the current data. We find the CMB+LSS+SN1
data give \Omega_{tot} =1.00^{+.07}_{-.03}, consistent with (non-baroque)
inflation theory. Restricting to \Omega_{tot}=1, we find a nearly scale
invariant spectrum, n_s =0.97^{+.08}_{-.05}. The CDM density, \Omega_{cdm}{\rm
h}^2 =.12^{+.01}_{-.01}, and baryon density, \Omega_b {\rm h}^2 =
>.022^{+.003}_{-.002}, are in the expected range. (The Big Bang nucleosynthesis
estimate is 0.019\pm 0.002.) Substantial dark (unclustered) energy is inferred,
\Omega_Q \approx 0.68 \pm 0.05, and CMB+LSS \Omega_Q values are compatible with
the independent SN1 estimates. The dark energy equation of state, crudely
parameterized by a quintessence-field pressure-to-density ratio w_Q, is not
well determined by CMB+LSS (w_Q < -0.4 at 95% CL), but when combined with SN1
the resulting w_Q < -0.7 limit is quite consistent with the w_Q=-1 cosmological
constant case.


title: Real-Time Detection of Optical Transients with RAPTOR

abstract:
  Fast variability of optical objects is an interesting though poorly explored
subject in modern astronomy. Real-time data processing and identification of
transient celestial events in the images is very important for such study as it
allows rapid follow-up with more sensitive instruments. We discuss an approach
which we have developed for the RAPTOR project, a pioneering closed-loop system
combining real-time transient detection with rapid follow-up. RAPTOR's data
processing pipeline is able to identify and localize an optical transient
within seconds after the observation. The testing we performed so far have been
confirming the effectiveness of our method for the optical transient detection.
The software pipeline we have developed for RAPTOR can easily be applied to the
data from other experiments.


title:
The eclipsing millisecond pulsar PSR J1740-5340 and its red straggler
  companion

abstract:
  We present a high-resolution echelle spectrum taken with the Very Large
Telescope and analyse archival Hubble Space Telescope photometry of the
recently identified companion of the eclipsing millisecond radio pulsar PSR
J1740-5340 in the globular cluster NGC 6397. From the spectrum, we show that
the companion is metal poor, as expected for a member of NGC 6397. Using
synthetic photometry, and assuming a true distance modulus of 12.13 +/- 0.15
mag and a colour excess of E(B-V) = 0.179, we derive a radius of 1.60 +/- 0.17
solar radii and an effective temperature of 5410 +/- 50 K, implying a
luminosity of 2.0 +/- 0.4 solar luminosities (1 sigma errors). These properties
make it similar to the so-called `sub-subgiants' in the old open cluster M67
and `red stragglers' in 47 Tuc, which have luminosities comparable to those of
turn-off stars, but cooler temperatures and larger radii. The light curve of
the companion is well described by ellipsoidal variations, and despite the
incomplete (~60%) phase coverage, we are able to derive good constraints on a
number of the system parameters. In particular, for the inclination we find a 2
sigma lower limit of i > 48 deg (i > 46 deg at 3 sigma). Assuming a pulsar mass
of 1.2 M_MSP < 2.4 solar masses, this implies a companion mass in the range
0.14 < M_comp < 0.38 solar masses. Combined with the photometric constraint, we
find a best fit for i ~ 50 deg and M_comp ~ 0.3 solar masses. We infer a Roche
lobe filling factor by radius of ~97%. [Abstract shortened]


title: A New Search Technique for Short Orbital Period Binary Pulsars

abstract:
  We describe a new and efficient technique which we call sideband or
phase-modulation searching that allows one to detect short period binary
pulsars in observations longer than the orbital period. The orbital motion of
the pulsar during long observations effectively modulates the phase of the
pulsar signal causing sidebands to appear around the pulsar spin frequency and
its harmonics in the Fourier transform. For the majority of binary radio
pulsars or Low-Mass X-ray Binaries (LMXBs), large numbers of sidebands are
present, allowing efficient searches using Fourier transforms of short portions
of the original power spectrum. Analysis of the complex amplitudes and phases
of the sidebands can provide enough information to solve for the Keplerian
orbital parameters. This technique is particularly applicable to radio pulsar
searches in globular clusters and searches for coherent X-ray pulsations from
LMXBs and is complementary to more standard ``acceleration'' searches.


title:
Small-Angle Scattering and Diffusion: Application to Relativistic Shock
  Acceleration

abstract:
  We investigate ways of accurately simulating the propagation of energetic
charged particles over small times where the standard Monte Carlo approximation
to diffusive transport breaks down. We find that a small-angle scattering
procedure with appropriately chosen step-lengths and scattering angles gives
accurate results, and we apply this to the simulation of propagation upstream
in relativistic shock acceleration.


title: The shroud around the "compact, symmetric" radio jets in NGC 1052

abstract:
  This is a paper on young jet material in a frustratingly complex environment.
  NGC 1052 has a compact, flat- or GHz-peaked-spectrum radio nucleus consisting
of bi-symmetric jets, oriented close to the plane of the sky. Many features on
both sides move away at v_app~0.26c (H_0=65 km/s/Mpc). VLBI at seven
frequencies shows a wide range of spectral shapes and brightness temperatures;
there is clearly free-free absorption, probably together with synchrotron
self-absorption, on both sides of the core. The absorbing structure is likely
to be geometrically thick and oriented roughly orthogonal to the jets, but it
is patchy.
  HI VLBI shows atomic gas in front of the approaching as well as the receding
jet. There appear to be three velocity systems, at least two of which are local
to the AGN environment. The "high velocity system", 125 to 200 km/s redward of
systemic, seems restricted to a shell 1 to 2 pc away from the core. Closer to
the centre, this gas might be largely ionised; it could cause the free-free
absorption.
  WSRT spectroscopy shows 1667 and 1665 MHz OH absorption over a wide velocity
range. OH and HI profile similarity suggests co-location of molecular and
atomic ``high velocity'' gas; the connection to H2O masing gas is unclear.
Further, at ``high velocity'' we detected the OH 1612 MHz satellite line in
absorption and the 1720 MHz line in emission, with complementary strengths.


title: Mach's Principle and Cosmology Term

abstract:
  Recent discovery of the rate of expansion of the Universe (Reiss A.G. et al.,
1998; Perlimutter S. et al., 1999) is connected with the vacuum energy in space
which, in turn, can be considered (Gliner E.B., 1965) as the cosmological
constant in Einstein's equation. In this article the cosmological term
predicted by Einstein is interpreted in terms of World's mass required by
Mach's principle. The Mach's principle itself is formulated as follows: inertia
masses of bodies, including those of fundamental particles, are determined by
the value of the cosmological term.


title: Molecular gas in the intergalactic medium of Stephan's Quintet

abstract:
  Stephan's Quintet (SQ) is a Hickson Compact Group well known for its complex
dynamical and star formation history and its rich intergalactic medium (IGM).
In order to study the extent, origin and fate of the intergalactic molecular
gas and its relation to the formation of stars outside galaxies and Tidal Dwarf
Galaxies (TDGs), we mapped with the IRAM 30m antenna carbon monoxide (CO)
towards several regions of the IGM in SQ. In two star forming regions (SQ A and
B), situated in very different environments, we detected unusually large
amounts of molecular gas ($3.1 \times 10^9$ \msun and $7 \times 10^8$ \msun,
respectively), covering an extended area (between 15 and 25 kpc). In both
regions the CO clouds have different properties and may be of a distinct
nature. The integrated CO line of SQ A is in particular much wider than in SQ
B. Its CO spectrum shows emission at two velocities (6000 and 6700 \kms),
coincident with two HI lines, with the stronger emission at 6000 \kms being
very smoothly distributed without a distinct peak in the starburst region. In
SQ B the CO emission coincides with that of tracers of star formation (\halpha,
near-infrared 15 $\mu$m and radio continuum). The CO peak lies close to the HI
peak towards a steep HI gradient. This is indicating that the molecular gas is
forming in-situ, with subsequent star formation taking place. The star forming
region at SQ B is the object in SQ that most resembles a TDG.


title:
Two X-Ray Bright Cataclysmic Variables with Unusual Activities: GZ Cnc
  and NSV 10934

abstract:
  We report on a discovery of unexpected activities in two X-ray bright dwarf
novae. GZ Cnc showed an anomalous clustering of outbursts in 2002, in contrast
to a low outburst frequency in the past record. The activity resembles an
increased activity seen in some intermediate polars or candidates. We
identified NSV 10934, X-ray selected high-amplitude variable star, as a dwarf
nova with unusually rapid decline. The outburst characteristics make NSV 10934
a twin of recently discovered intermediate polar (HT Cam) with dwarf nova-type
outbursts. We propose that these activities in X-ray strong dwarf novae may be
a previously overlooked manifestation of outburst activities in magnetic
cataclysmic variables.


title: Spectroscopy of BL Lac Objects: new redshifts and mis-identified sources

abstract:
  We are carrying out a program of high signal to noise optical spectroscopy of
BL Lacs with unknown or tentative redshift. Here we report some preliminary
results. New redshifts are measured for PKS0754+100 (z=0.266) and 1ES0715-259
(z=0.464) . From lineless spectra of PG1553+113 and PKS1722+119 we set a lower
limit of z>0.3 for both sources. In two cases (UM493 and 1620+103) stellar
spectra indicate a wrong classification.


title: Carbon Monoxide bands in M dwarfs

abstract:
  We compare the observational and theoretical spectra of the $\Delta v$ = 2 CO
bands in a range of M dwarfs. We investigate the dependence of theoretical
spectra on effective temperatures as well as carbon abundance. In general we
find that the synthetic CO bands fit the observed data extremely well and are
excellent diagnostics. In particular the synthetic spectra reasonably match
observations and the best fit temperatures are similar to those found by
empirical methods. We also examine the \CDC isotopic ratio. We find that
fundamental $^{13}$CO bands around 2.345 and 2.375 $\mu$m are good
discriminators for the \CDC ratio in M dwarfs. The 2.375 $\mu$m is more useful
because it doesn't suffer such serious contamination by water vapour
transitions. Our current dataset does not quite have the wavelength coverage to
perform a reliable determination of the \CDC ratio in M dwarfs. For this we
recommend observing the region 2.31--2.40 $\mu$m at a resolution of better than
1000. Alternatively the observational problems of contamination by water vapour
at 2.345 $\mu$m maybe solved by observing at resolutions of around 50000. We
also investigated the possibility of using the $\Delta v$ = 1 CO bands around
4.5 $\mu$m. We find that the contamination due to water vapour is even more of
a problem at these wavelengths.


title:
Hydrostatic equilibrium of insular, static, spherically symmetric,
  perfect fluid solutions in general relativity

abstract:
  An analysis of insular solutions of Einstein's field equations for static,
spherically symmetric, source mass, on the basis of exterior Schwarzschild
solution is presented. Following the analysis, we demonstrate that the {\em
regular} solutions governed by a self-bound (that is, the surface density does
not vanish together with pressure) equation of state (EOS) or density variation
can not exist in the state of hydrostatic equilibrium, because the source mass
which belongs to them, does not represent the `actual mass' appears in the
exterior Schwarzschild solution. The only configuration which could exist in
this regard is governed by the homogeneous density distribution (that is, the
interior Schwarzschild solution). Other structures which naturally fulfill the
requirement of the source mass, set up by exterior Schwarzschild solution (and,
therefore, can exist in hydrostatic equilibrium) are either governed by
gravitationally-bound regular solutions (that is, the surface density also
vanishes together with pressure), or self-bound singular solutions (that is,
the pressure and density both become infinity at the centre).


title:
The Effect of Radiative Cooling on the Sunyaev-Zel'dovich Cluster Counts
  and Angular Power Spectrum: Analytic Treatment

abstract:
  Recently, the entropy excess detected in the central cores of groups and
clusters has been successfully interpreted as being due to radiative cooling of
the hot intragroup/intracluster gas. In such a scenario, the entropy floors
$S_{\rm floor}$ in groups/clusters at any given redshift are completely
determined by the conservation of energy. In combination with the equation of
hydrostatic equilibrium and the universal density profile for dark matter, this
allows us to derive the remaining gas distribution of groups and clusters after
the cooled material is removed. Together with the Press-Schechter mass function
we are able to evaluate effectively how radiative cooling can modify the
predictions of SZ cluster counts and power spectrum. It appears that our
analytic results are in good agreement with those found by hydrodynamical
simulations. Namely, cooling leads to a moderate decrease of the predicted SZ
cluster counts and power spectrum as compared with standard scenario. However,
without taking into account energy feedback from star formation which may
greatly suppress cooling efficiency, it is still premature to claim that this
modification is significant for the cosmological applications of cluster SZ
effect.


title:
Spherical gravitational collapse and electromagnetic fields in radially
  homothetic spacetimes

abstract:
  We consider a spherically symmetric, Petrov-type D, spacetime with
hyper-surface orthogonal, radial, homothetic Killing vector. In this work, some
general properties of this spacetime for non-singular and non-degenerate data
are presented. We also present the source-free electromagnetic fields in this
spacetime. We then discuss general astrophysical relevance of the results
obtained for this spacetime.


title: Ellipticity analysis of the BOOMERanG CMB maps

abstract:
  The properties of the Cosmic Microwave Background (CMB) maps carry valuable
cosmological information. Here we report the results of the analysis hot and
cold CMB anisotropy spots in the BOOMERanG 150 GHz map in terms of number,
area, ellipticity, vs. temperature threshold. We carried out this analysis for
the map obtained by summing independent measurement channels (signal plus noise
map) and for a comparison map (noise only map) obtained by differencing the
same channels. The anisotropy areas (spots) have been identified for both maps
for various temperature thresholds and a catalog of the spots has been
produced. The orientation (obliquity) of the spots is random for both maps. We
computed the mean elongation of spots obtained from the maps at a given
temperature threshold using a simple estimator. We found that for the sum map
there is a region of temperature thresholds where the average elongation is not
dependent on the threshold. Its value is ~ 2.3 for cold areas and ~ 2.2 for hot
areas. This is a non-trivial result. The bias of the estimator is less than 0.4
for areas of size less than 30', and smaller for larger areas. The presence of
noise also biases the ellipticity by less than 0.3. These biases have not been
subtracted in the results quoted above. The threshold independent and random
obliquity behaviour in the sum map is stable against pointing reconstruction
accuracy and noise level of the data, thus confirming that these are actual
properties of the dataset. The data used here give a hint of high ellipticity
for the largest spots. Analogous elongation properties of CMB anisotropies had
been detected for COBE-DMR 4-year data. If this is due to geodesics mixing, it
would point to a non zero curvature of the Universe.


title: Arrows of Time and Chaotic Properties of the Cosmic Background Radiation

abstract:
  We advance a new viewpoint on the connection between the the thermodynamical
and cosmological arrows of time, which can be traced via the properties of
Cosmic Microwave Background (CMB) radiation. We show that in the
Friedmann-Robertson-Walker Universe with negative curvature there is a
necessary ingredient for the existence of the thermodynamical arrow of time. It
is based on the dynamical instability of motion along null geodesics in a
hyperbolic space. Together with special (de-correlated) initial conditions,
this mechanism is sufficient for the thermodynamical arrow, whereas the special
initial conditions alone are able to generate only a pre-arrow of time. Since
the negatively curved space will expand forever, this provides a direct
connection between the thermodynamical and cosmological arrows of time. The
structural stability of the geodesic flows on hyperbolic spaces and hence the
robustness of the proposed mechanism is especially stressed. We then point out
that the main relations of equilibrium statistical thermodynamics (including
the second law) do not necessarily depend on any arrow of time. Finally we
formulate a {\it curvature anthropic principle}, which stipulates the negative
curvature as a necessary condition for the time asymmetric Universe with an
observer. CMB has to carry the signature of this principle as well.


title: Energy Budget and Imaging Spectroscopy of a Compact Flare

abstract:
  We present the analysis of a compact flare that occurred on 2002/02/26 at
10:26 UT, seen by both RHESSI and TRACE. The size of the nearly circular hard
X-ray source is determined to be 4.7(+-1.5)" from the modulation profiles of
the RHESSI collimators. The power-law distribution of non-thermal photons is
observed to extend down to 10 keV without flattening, and to soften with
increasing distance from the flare kernel. The former indicates that the energy
of the precipitating flare electron population is larger than previously
estimated: it amounts to 2.6(+-0.8)10^30 erg above 10 keV, assuming
thick-target emission. The thermal energy content of the soft X-ray source
(isothermal temperature of 20.8(+-0.9)MK) and its radiated power were derived
from the thermal emission at low energies. TRACE has observed a low-temperature
ejection in the form of a constricted bubble, which is interpreted as a
reconnection jet. Its initial energy of motion is estimated. Using data from
both satellites, an energy budget for this flare is derived. The kinetic energy
of the jet bulk motion and the thermal and radiated energies of the flare
kernel were more than an order of magnitude smaller than the derived electron
beam energy. A movie is available on the CD-ROM accompanying this volume.


title: Microflares and Hot Component in Solar Active Regions

abstract:
  Open-shutter RHESSI observations of 3-15 keV X-rays are found to exhibit
active region transient brightenings and microflares at a rate of at least 10
per hour occurring even during the periods of lowest solar activity so far in
the mission. A thermal component fitted by temperatures of 6-14 MK dominates
from 3 keV to about 9 keV, but can be traced up to 14 keV in some cases, and
has an average duration of 131(+-103) seconds at 7-8 keV. The duration
increases with decreasing photon energy. The peak count rate defined by
cross-correlation is delayed at low energies. The temperature peaks early in
the event and then decreases, whereas the emission measure increases throughout
the event. The properties are consistent with thermal conduction dominating the
evolution. In some of the bigger events, a second component was found in the
11-14 keV range extending down to 8 keV in some cases. The duration is
typically 3 times shorter and ends near the peak time of the thermal component
consistent with the Neupert effect of regular flares. Therefore the second
component is suggested to be of non-thermal origin, presumably causing the
beam-driven evaporation of the first component. The two components can be
separated and analyzed in detail for the first time. Low-keV measurements allow
a reliable estimate of the energy input by microflares necessary to assess
their relevance for coronal heating.


title: V2051 Oph's disc evolution on decline from superoutburst

abstract:
  We present an Eclipse Mapping analysis of ten eclipses taken during decline
from superoutburst of the dwarf nova V2051 Oph. On decline from superoutburst
the disc cools down considerably from nearly 50,000 K in the intermediate disc
(approx. 0.2 R_L1) near maximum to about 25,000 K at the end of our observing
run, i.e. within 4 days. The average mass accretion rate through the disc drops
in the same time from 10^18 g/s to below 10^17 g/s.
  While in some maps the brightness temperature follows the steady state model,
in others the temperature profile shows flattenings and/or indication of an
inward travelling cooling front with a speed of approximately -0.12 km/s,
possibly a reflected heating front with a speed of +1.8 km/s and a newly
reflected cooling front with the same speed as the first one. Such scenario has
been predicted (Menou et al. 2000) but not been observed before. Furthermore,
we see a prograde precession of the enlarged disc with a precession period of
about 52.5 hours in very good agreement with the independently determined
superhump period observed by Kiyota & Kato (1998). At the same time, the
uneclipsed component -- presumeably a disc wind -- decreases significantly in
strength during decline from superoutburst.


title: From Fermi-Pasta-Ulam Problem to Galaxies: The Quest for Relaxation

abstract:
  The major problem posed by the Fermi-Pasta-Ulam work was the relaxation
(thermalization) of a many-body system. We review two approaches to this
problem, the ergodic theory and Langevin (stochastic) equation ones, which have
been applied for the description of statistical mechanics of stellar systems.
Among the particular problems that we consider, are 1-dimensional long-range
interacting systems and iterated maps and 3-dimensional N-body gravitating
systems.


title: The Resolved Red Giant Branches of E/S0 Galaxies

abstract:
  Formation paradigms for massive galaxies have long centered around two
antipodal hypotheses -- the monolithic-collapse and the accretion/merger
scenarios. Empirical data on the stellar contents of galaxy halos is crucial in
order to develop galaxy formation and assembly scenarios which have their root
in observations, rather than in numerical simulations. Hubble Space Telescope
(HST) has enabled us to study directly individual stars in the nearby E/S0
galaxies Cen A, NGC 3115, NGC 5102, and NGC 404. We here present and discuss
HST single-star photometry in V and I bands. Using color-magnitude diagrams and
stellar luminosity functions, we gauge the galaxies' stellar contents. This can
be done at more than one position in the halo, but data with deeper limiting
magnitudes are desired to quantify the variation of metallicity with
galactocentric radius. We here compare the color distributions of red giant
stars with stellar isochrones, and we intercompare the galaxies' halo
populations, noting that their total absolute V magnitudes cover the range from
about -21.5 to -17.5. In the future, we plan to model the stellar metallicity
distributions with the aim to constrain chemical enrichment scenarios, a step
towards unravelling the evolutionary history of elliptical and lenticular
galaxies.


title:
Consequences of the non gaussian character of the stochastic excitation
  for solar-type oscillations

abstract:
  Our recent study, based on a 3D numerical simulation, suggested that the
stochastic excitation of solar p-modes has a non gaussian nature and a non
gaussian model was proposed which results in a good agreement between the
computed rate $P$ at which p-modes are excited and the solar seismic
observational constraints.
  In the present work, we study some consequences of this non-gaussian model on
the rate P at which p-modes are excited in intermediate mass stars (1 Mo < M <
2 Mo). The non gaussian model changes substantially the spectrum of P at high
frequency compared with the commonly assumed gaussian model. The largest
effects on P are found for stars in the mass range ~ 1.5-1.6 Mo. They are found
large enough that observatins in solar-like oscillating stars observed with
space based seismology missions (e.g. COROT) will be able to confirm or reject
the gaussian nature of stochastic excitation.


title: X-ray and Optical Studies of Millisecond Pulsars in 47 Tucanae

abstract:
  Our Chandra X-ray observation of the globular cluster 47 Tuc clearly detected
most of the 16 MSPs with precise radio positions, and indicates probable X-ray
emission from the remainder. The MSPs are soft (BB kT 0.2-0.3 keV) and faint
(Lx few 10^{30} ergs/s), and generally consistent with thermal emission from
small polar caps. An additional 40 soft X-ray sources are consistent with the
known MSPs in X-ray colors, luminosity, and radial distribution within the
cluster (and thus mass). We note that these MSPs display a flatter Lx to Edot
relation than pulsars and MSPs in the field, consistent with polar cap heating
models for younger MSPs and may suggest the surface magnetic field has been
modified by repeated accretion episodes to include multipole components.
Correlating HST images, radio timing positions, and the Chandra dataset has
allowed optical searches for MSP binary companions. The MSP 47 Tuc-U is
coincident with a blue star exhibiting sinusoidal variations that agree in
period and phase with the heated face of the WD companion. Another blue
variable star (and X-ray source) agrees in period and phase with the companion
to 47 Tuc-W (which lacks an accurate timing position); this companion is
probably a main sequence star.


title:
Collision-induced galaxy formation: semi-analytical model and
  multi-wavelength predictions

abstract:
  A semi-analytic model is proposed that couples the Press-Schechter formalism
for the number of galaxies with a prescription for galaxy-galaxy interactions
that enables to follow the evolution of galaxy morphologies along the Hubble
sequence. Within this framework, we calculate the chemo-spectrophotometric
evolution of galaxies to obtain spectral energy distributions. We find that
such an approach is very successful in reproducing the statistical properties
of galaxies as well as their time evolution. We are able to make predictions as
a function of galaxy type: for clarity, we restrict ourselves to two categories
of galaxies: early and late types that are identified with ellipticals and
disks. In our model, irregulars are simply an early stage of galaxy formation.
In particular, we obtain good matches for the galaxy counts and redshift
distributions of sources from UV to submm wavelengths. We also reproduce the
observed cosmic star formation history and the diffuse background radiation,
and make predictions as to the epoch and wavelength at which the dust-shrouded
star formation of spheroids begins to dominate over the star formation that
occurs more quiescently in disks. A new prediction of our model is a rise in
the FIR luminosity density with increasing redshift, peaking at about $z\sim
3$, and with a ratio to the local luminosity density $\rho_{L,\nu} (z =
z_{peak})/ \rho_{L,\nu} (z = 0)$ about 10 times higher than that in the blue
(B-band) which peaks near $z\sim 2$.


title:
Rapidly Evolving Circularly Polarized Emission during the 1994 Outburst
  of GRO J1665-40

abstract:
  We report the detection of circular polarization during the 1994 outburst of
the Galactic microquasar GRO J1655-40. The circular polarization is clearly
detected at 1.4 and 2.4GHz, but not at 4.8 and 8.4GHz, where its magnitude
never exceeds 5 mJy. Both the sign and magnitude of the circular polarization
evolve during the outburst. The time dependence and magnitude of the polarized
emission can be qualitatively explained by a model based on synchrotron
emission from the outbursts, but is most consistent with circular polarization
arising from propagation effects through the relativistic plasma surrounding
the object.


title: Fusion cycles in stars and stellar neutrinos

abstract:
  Starting from the early works by Weizsaecker and Bethe about fusion cycles
and energy conversion in stars, a brief survey of thermonuclear processes in
stars leading to contemporary research problems in this field is given. Special
emphasis is put on the physics of stellar and, in particular, solar neutrinos
which is at the frontline of current investigations.


title:
Generation of Primordial Cosmological Perturbations from Statistical
  Mechanical Models

abstract:
  The initial conditions describing seed fluctuations for the formation of
structure in standard cosmological models, i.e.the Harrison-Zeldovich
distribution, have very characteristic ``super-homogeneous'' properties: they
are statistically translation invariant, isotropic, and the variance of the
mass fluctuations in a region of volume V grows slower than V. We discuss the
geometrical construction of distributions of points in ${\bf R}^3$ with similar
properties encountered in tiling and in statistical physics, e.g. the Gibbs
distribution of a one-component system of charged particles in a uniform
background (OCP). Modifications of the OCP can produce equilibrium correlations
of the kind assumed in the cosmological context. We then describe how such
systems can be used for the generation of initial conditions in gravitational
$N$-body simulations.


title: Missing Parameters in the CMB Physics

abstract:
  The lecture is devoted to the comparison of a few models of cosmic
recombination kinetics with recent CMB anisotropy data and to corresponding
predictions for the upcoming PLANCK mission. The influence of additional
sources of ionized photons at the epoch of hydrogen recombination may restrict
our possibility to estimate the density of baryonic fraction of matter when
using PLANCK data. This new source of degeneracy of the cosmological parameters
which can be estimated from the CMB anisotropy data can mimic the distortion of
the CMB power spectrum for different models of baryonic matter. I would like to
point out that realistic values of the cosmological parameters can not be
obtained without PLANCK polarization data.


title:
Chandra observations of the recurrent nova CI Aql after its April 2000
  outburst

abstract:
  We report the results of two Chandra observations of the recurrent nova CI
Aql at 14 and 16 months after its outburst in April 2000, respectively. The
X-ray emission is faint in both cases, without any noticeable change in
spectrum or intensity. Although the emission is very soft, it is not luminous
enough to be due to late-time H-burning. This implies that the luminous
supersoft phase ended even before the time predicted by the most recent
calculations. The details of the X-ray spectrum, together with the fact that
the observed X-ray intensity is brighter than pre-outburst (1992/1993), suggest
that the observed X-ray emission is either due to ionization of the
circumstellar material or due to the shocks within the wind and/or with the
surrounding medium.


title:
Seismic diagnostics on stellar convection treatment from oscillation
  amplitudes of p-modes

abstract:
  The excitation rate P of solar p-modes is computed with a model of stochatic
excitation which involves constraints on the averaged properties of the solar
turbulence. These constraints are obtained from a 3D simulation. Resulting
values for P are found ~9 times larger than when the calculation assumes
properties of turbulent convection which are derived from an 1D solar model
based on Gough (1977)'s formulation of the mixing-length theory (GMLT). This
difference is mainly due to the assumed values for the mean anisotropy of the
velocity field in each case.Calculations based on 3D constraints bring the P
maximum closer to the observational one.We also compute P for several models of
intermediate mass stars (1Mo < M < 2Mo). Differences in the values of P_max
between models computed with the classical mixing-length theory and GMLT models
are found large enough for main sequence stars to suggest that measurements of
P in this mass range will be able to discriminate between different models of
turbulent convection.


title: From Spirals to Low Surface Brightness galaxies

abstract:
  We show that simple models of the chemical and spectrophotometric evolution
of galaxies can be used to explore the properties of present-day galaxies and
especially the causes of the observed variety among disc galaxies. We focus on
the link between ``classical'' spirals and Low Surface Brightness galaxies.


title: Dark energy and dissipation

abstract:
  Most of the models leading to a current state of cosmic accelerated expansion
fail to address the coincidence problem, i.e., that the dark energy density and
the energy density of the matter fluid are of the same order precisely today.
We show that a way to drive late acceleration and simultaneously solve the
aforesaid problem is assuming the matter fluid dissipative[1].


title: Signatures of primordial helicity in the CMBR

abstract:
  We have studied ways in which helical primordial magnetic fields could be
constrained by measurements of the cosmic microwave background radiation
(CMBR). If there were helical flows in the primordial plasma at the time of
recombination, they would produce parity violating temperature-polarization
correlations ($C_l^{TB}$ and $C_l^{EB}$). However, the magnitude of helical
flows induced by helical magnetic fields is unobservably small. We discuss an
alternate scheme for extracting the helicity of a stochastically homogeneous
and isotropic primordial magnetic field using Faraday rotation measure maps of
the CMBR and the power spectrum of B-type polarization ($C_l^{BB}$).


title:
Molecular Gas and Dust at z = 2.6 in SMM J14011+0252: A Strongly Lensed,
  Ultraluminous Galaxy, Not a Huge, Massive Disk

abstract:
  We used the IRAM Interferometer to detect CO(3-2), CO(7-6), and 1.3 mm dust
continuum emission from the submillimeter galaxy SMM J14011+0252 at a redshift
of 2.6. Contrary to a recent claim that the CO was extended over 6.6 arcsec (57
kpc), the new data yield a size of 2 x 0.5 arcsec for the CO and the dust.
Although previous results placed the CO peak in a region with no visible
counterpart, the new maps show the CO and dust are centered on the J1 complex
seen on K-band and optical images. We suggest the CO is gravitationally lensed
not only by the foreground cluster A1835, but also by an individual galaxy on
the line of sight. Comparison of measured and intrinsic CO brightness
temperatures indicates the CO size is magnified by a factor of 25 +/- 5. After
correcting for lensing, we derive a true CO diameter of ~0.08 arcsec (700 pc),
consistent with a compact circumnuclear disk of warm molecular gas similar to
that in Arp 220. The high magnification means the true size, far-IR luminosity,
star formation rate, CO luminosity, and molecular gas mass are all comparable
with those in present-epoch ultraluminous IR galaxies, not with those of a
huge, massive, early-universe galactic disk.


title: SNAP Near Infrared Detectors

abstract:
  The SuperNova/Acceleration Probe (SNAP) will measure precisely the
cosmological expansion history over both the acceleration and deceleration
epochs and thereby constrain the nature of the dark energy that dominates our
universe today. The SNAP focal plane contains equal areas of optical CCDs and
NIR sensors and an integral field spectrograph. Having over 150 million pixels
and a field-of-view of 0.34 square degrees, the SNAP NIR system will be the
largest yet constructed. With sensitivity in the range 0.9-1.7 microns, it will
detect Type Ia supernovae between z = 1 and 1.7 and will provide follow-up
precision photometry for all supernovae. HgCdTe technology, with a cut-off
tuned to 1.7 microns, will permit passive cooling at 140 K while maintaining
noise below zodiacal levels. By dithering to remove the effects of intrapixel
variations and by careful attention to other instrumental effects, we expect to
control relative photometric accuracy below a few hundredths of a magnitude.
Because SNAP continuously revisits the same fields we will be able to achieve
outstanding statistical precision on the photometry of reference stars in these
fields, allowing precise monitoring of our detectors. The capabilities of the
NIR system for broadening the science reach of SNAP are discussed.


title: Variable Speed of Light Theories

abstract:
  Two variable speed of light models and their physical consequences are
investigated.


title: The Wide-Field Imaging Interferometry Testbed III. Metrology Subsystem

abstract:
  In order for data products from WIIT to be as robust as possible, the
alignment and mechanical positions of source, receiver, and detector components
must be controlled and measured with extreme precision and accuracy, and the
ambient environment must be monitored to allow environmental effects to be
correlated with even small perturbations to fringe data. Relevant detailed
anatomy of many testbed components and assemblies are described. The system of
displacement measuring interferometers (DMI), optical encoders, optical
alignment tools, optical power monitors, and temperature sensors implemented
for control and monitoring of the testbed is presented.


title: The Challenge to Large Optical Telescopes from X-ray Astronomy

abstract:
  In the ROSAT era of the mid-1990's, the problems facing deep X-ray surveys
could be largely solved with 10 m class telescopes. In the first decade of this
new millennium, with X-ray telescopes such as the Chandra X-ray Observatory and
XMM-Newton in operation, deep X-ray surveys are challenging 10 m telescopes.
For example, in the Chandra Deep Field surveys, approximately 30% of the X-ray
sources have optical counterparts fainter than R=25 (I=24).
  This paper reviews current progress with 6-10 m class telescopes in following
up sources discovered in deep X-ray surveys, including results from several
X-ray surveys which have depended on telescopes such as Keck, VLT and HET.
Topics include the prospects for detecting extreme redshift (z>6) quasars and
the first detections of normal and starburst galaxies at cosmologically
interesting distances in the X-ray band.
  X-ray astronomy can significantly bolster the science case for the next
generation of large aperture (30-100 m) ground-based telescopes and has already
provided targets for these large telescopes through the Chandra and XMM-Newton
surveys. The next generation of X-ray telescopes will continue to challenge
large optical telescopes; this review concludes with a discussion of prospects
from new X-ray missions coming into operation on a 5-30 year timescale.


title: Lepton Acceleration by Relativistic Collisionless Magnetic Reconnection

abstract:
  We have calculated self-consistent equilibria of a collisionless relativistic
electron-positron gas in the vicinity of a magnetic $X-$point. For the
considered conditions, pertinent to extra-galactic jets, we find that leptons
are accelerated up to Lorentz factors $\Gamma_0 = \kappa e B_0L {\cal E}^2
/mc^2 \gg 1$, where $B_0$ is the typical magnetic field strength, ${\cal
E}\equiv E_0/B_0$, with $E_0$ the reconnection electric field, $L$ is the
length scale of the magnetic field, and $\kappa \approx 12$. The acceleration
is due to the dominance of the electric field over the magnetic field in a
region around the $X-$point. The distribution function of the accelerated
leptons is found to be approximately $dn/d\gamma \propto \gamma^{-1}$ for
$\gamma \lesssim \Gamma_0$. The apparent distribution function may be steeper
than $\gamma^{-1}$ due to the distribution of $\Gamma_0$ values and/or the
radiative losses. Self-consistent equilibria are found only for plasma inflow
rates to the $X-$point less than a critical value.


title: The Extra-Solar Planet Imager (ESPI)

abstract:
  ESPI has been proposed for direct imaging and spectral analysis of giant
planets orbiting solar-type stars. ESPI extends the concept suggested by
Nisenson and Papaliolios (2001) for a square aperture apodized telescope that
has sufficient dynamic range to directly detect exo-planets. With a 1.5 M
square mirror, ESPI can deliver high dynamic range imagery as close as 0.3
arcseconds to bright sources, permitting a sensitive search for exoplanets
around nearby stars and a study of their characteristics in reflected light.


title: "Hidden" Seyfert 2 Galaxies and the X-ray Background

abstract:
  Obscured active galactic nuclei, which are classified optically as type 2
(narrow-line) Seyfert galaxies in the local universe, are by far the most
promising candidates for the origin of the hard (2-10 keV) X-ray background
radiation. However, optical follow-up observations of faint X-ray sources in
deep Chandra images have revealed surprising numbers of apparently normal
galaxies at modest redshift. Such objects represent ~40-60% of the sources
classified in deep Chandra surveys, raising the possibility that the X-ray
galaxy population has evolved with cosmic time. Alternatively, most of the
faint X-ray galaxies in question are so distant that their angular diameters
are comparable to the slit widths used in ground-based spectroscopic
observations; thus, their nuclear spectral features may be overwhelmed
(``hidden'') by host-galaxy light. To test this hypothesis, we have obtained
integrated spectra of a sample of nearby, well-studied Seyfert 2 galaxies. The
data, which accurately simulate observations of distant Chandra sources,
demonstrate convincingly that the defining spectral signatures of Seyfert 2s
can be hidden by light from their host galaxies. In fact, 60% of the observed
objects would not be classified as Seyfert 2s on the basis of their integrated
spectra, similar to the fraction of faint X-ray sources identified with
``normal'' galaxies. Thus, the numbers of narrow-line active galaxies in deep
Chandra surveys (and perhaps all ground-based spectroscopic surveys of distant
galaxies) are likely to have been underestimated.


title:
A Search for "Dwarf" Seyfert Nuclei. VI. Properties of Emission-Line
  Nuclei in Nearby Galaxies

abstract:
  We use the database from Paper III to quantify the global and nuclear
properties of emission-line nuclei in the Palomar spectroscopic survey of
nearby galaxies. We show that the host galaxies of Seyferts, LINERs, and
transition objects share remarkably similar large-scale properties and local
environments. The distinguishing traits emerge on nuclear scales. Compared with
LINERs, Seyfert nuclei are an order of magnitude more luminous and exhibit
higher electron densities and internal extinction. We suggest that Seyfert
galaxies possess characteristically more gas-rich circumnuclear regions, and
hence a more abundant fuel reservoir and plausibly higher accretion rates. The
differences between the ionization state of the narrow emission-line regions of
Seyferts and LINERs can be partly explained by the differences in their nebular
properties. Transition-type objects are consistent with being composite
(LINER/\hii) systems. With very few exceptions, the stellar population within
the central few hundred parsecs of the host galaxies is uniformly old, a
finding that presents a serious challenge to starburst or post-starburst models
for these objects. Seyferts and LINERs have virtually indistinguishable
velocity fields as inferred from their line widths and line asymmetries. All
three classes of objects obey a strong correlation between line width and line
luminosity. We argue that the angular momentum content of circumnuclear gas may
be an important factor in determining whether a nucleus becomes active.
Finally, we discuss some possible complications for the unification model of
Seyfert galaxies posed by our observations. (Abridged)


title: The Enigma of the Highest Energy Particles of Nature

abstract:
  Historically cosmic rays have always been at the intersection of astrophysics
with particle physics. This is still and especially true in current days where
experimenters routinely observe atmospheric showers from particles whose
energies reach macroscopic values up to about 50 Joules. This dwarfs energies
achieved in the laboratory by about eight orders of magnitude in the detector
frame and three orders of magnitude in the center of mass. While the existence
of these highest energy cosmic rays does not necessarily testify physics not
yet discovered, their macroscopic energies likely links their origin to the
most energetic processes in the Universe. Explanations range from conventional
shock acceleration to particle physics beyond the Standard Model and processes
taking place at the earliest moments of our Universe. While motivation for some
of the more exotic scenarios may have diminished by newest data, conventional
shock acceleration scenarios remain to be challenged by the apparent isotropy
of cosmic ray arrival directions which may not be easy to reconcile with a
highly structured and magnetized Universe. Fortunately, many new experimental
activities promise a strong increase of statistics at the highest energies and
a combination with gamma-ray and neutrino astrophysics will put strong
constraints on all these theoretical models. This short review is far from
complete and instead presents a selection of aspects regarded by the author as
interesting and/or promising for the future.


title: The Black Hole-Bulge Relationship in QSOs

abstract:
  We use QSO emission-line widths to examine the black hole mass - sigma
relationship as a function of redshift and to extend the relationship to larger
masses. Supermassive black holes in galactic nuclei are closely related to the
bulge of the host galaxy. The mass of the black hole, M_BH, increases with the
bulge luminosity and with the velocity dispersion of the bulge stars, sigma_*.
An important clue to the origin of this correlation would be an observational
determination of the evolution, if any, in the M_BH - sigma_* relationship as a
function of cosmic time. The high luminosity of QSOs affords the potential for
studies at large redshifts. We derive black hole masses from the continuum
luminosity and the width of the broad Hbeta line and sigma_* from the width of
the narrow [O III] lines. We find that radio quiet QSOs conform to the
established M_BH - sigma_* relationship up to values M_BH of 10 billion solar
masses, with no discernible change in the relationship out to redshifts of $z
\approx 3$. These results are consistent with the idea that the growth of
supermassive black holes and massive bulges occurred simultaneously.


title: On the origin of high eccentricity halo stars

abstract:
  The present-day chemical and dynamical properties of the Milky Way are
signatures of the Galaxy's formation and evolution. Using a self consistent
chemodynamical evolution code we examine these properties within the currently
favoured paradigm for galaxy formation - hierarchical clustering within a CDM
cosmology. Our Tree N-body/Smoothed Particle Hydrodynamics code includes a
self-consistent treatment of gravity, hydrodynamics, radiative cooling, star
formation, supernova feedback and chemical enrichment. Two models are described
which explore the role of small-scale density perturbations in driving the
evolution of structure within the Milky Way. The relationship between
metallicity and kinematics of halo stars are quantified and the implications
for galaxy formation discussed. While high-eccentricity halo stars have
previously been considered a signature of ``rapid collapse'', we suggest that
many such stars may have come from recently accreted satellites.


title:
Disappearing Dark Matter in Brane World Cosmology: New Limits on
  Noncompact Extra Dimensions

abstract:
  We explore cosmological implications of dark matter as massive particles
trapped on a brane embedded in a Randall-Sundrum noncompact higher dimension
$AdS_5$ space. It is an unavoidable consequence of this cosmology that massive
particles are metastable and can disappear into the bulk dimension. Here, we
show that a massive dark matter particle (e.g. the lightest supersymmetric
particle) is likely to have the shortest lifetime for disappearing into the
bulk. We examine cosmological constraints on this new paradigm and show that
disappearing dark matter is consistent (at the 95% confidence level) with all
cosmological constraints, i.e. present observations of Type Ia supernovae at
the highest redshift, trends in the mass-to-light ratios of galaxy clusters
with redshift, the fraction of X-ray emitting gas in rich clusters, and the
spectrum of power fluctuations in the cosmic microwave background. A best $2
\sigma$ concordance region is identified corresponding to a mean lifetime for
dark matter disappearance of $15 \le \Gamma^{-1} \le 80$ Gyr. The implication
of these results for brane-world physics is discussed.


title: Near Infrared Adaptive Optics Imaging of the Embedded Cluster NGC 2024

abstract:
  We present the results of a high resolution near infrared adaptive optics
survey of the young obscured star forming region NGC 2024. Out of the total 73
stars detected in the adaptive optics survey of the cluster, we find 3 binaries
and one triple. The resulting companion star fraction, 7+/-3% in the separation
range of 0.''35-2.''3 (145-950 AU), is consistent with that expected from the
multiplicity of mature solar-type stars in the local neighborhood. Our survey
was sensitive to faint secondaries but no companions with Delta K' > 1.2
magnitudes are detected within 2'' of any star. The cluster has a K' luminosity
function that peaks at ~12, and although our completeness limit was 17.7
magnitude at K', the faintest star we detect had a K' magnitude of 16.62.


title:
Chandra observations of the galaxy cluster A478: the interaction of hot
  gas and radio plasma in the core, and an improved determination of the
  Compton y-parameter

abstract:
  We present the results from a 42 ks \chandra ACIS observation of the galaxy
cluster A478. This cluster is generally considered to be highly relaxed. The
\chandra image reveals, for the first time, X-ray cavities in the hot gas
within the central 15 kpc radius of A478. Two weak and small ($\sim$ 4 kpc)
radio lobes that extend from the central nucleus, are detected in a 1.4 GHz VLA
observation. The radio lobes are roughly along the direction of the X-ray
cavities, but are much smaller than the X-ray cavities. We propose a ``donut''
configuration for the hot gas within the central 15 kpc, created by the
interaction of the gas with the radio plasma that originated from the nucleus.
The current radio activity of the central radio source is weak ($\sim$ 0.2% of
Hydra A) and the total radio power is at least 10 times smaller than the
minimum power needed to create the cavities. We compare A478 with other galaxy
clusters where similar X-ray cavities were found. A478 and A4059 host much
weaker central radio sources than do others with similar size X-ray cavities.
On larger scales, deprojected temperature and density profiles are obtained for
A478. We used these to derive the Compton y-parameter, for the first time,
through direct integration. The result has a much smaller statistical
uncertainty than previous ones. This serves as an example of how high quality
X-ray data can help constrain H$_{0}$. The corresponding H$_{0}$ also was
derived combining the available Sunyaev-Zeldovich effect (SZE) measurement.


title: A Search for Lyman alpha Emitters at Redshift 3.7

abstract:
  We present the results of a survey for emission-line objects based on optical
intermediate-band ($\lambda_{\rm c}$ = 5736 \AA ~ and $\Delta\lambda$ = 280
\AA) and broad-band ($B$, $V$, $R$, and $i^\prime$) observations of the
Subaru/XMM-Newton Deep Field on the 8.2 m Subaru telescope with the Subaru
Prime Focus Camera, Suprime-Cam. All the data were obtained during the
guaranteed time observations of the Suprime-Cam instrument. The
intermediate-band image covered a sky area with 10\minpoint62 $\times
12\minpoint40 \approx 132$ arcmin$^2$ in the Subaru/XMM-Newton Deep Field
(Ouchi et al.).
  Using this image, we have found 23 emission-line sources whose observed
emission-line equivalent widths are greater than 250 \AA. Their optical
multicolor properties indicate that six emission-line sources are Ly$\alpha$
emitters at $z \approx$ 3.7 ($\Delta z \approx 0.22$). They are either intense
starburst galaxies or active galactic nuclei like quasars at $z \approx$ 3.7.
Two more emission-line sources may also be Ly$\alpha$ emitters at $z \approx$
3.7 although their multicolor properties are marginal. Among the remaining 15
emission-line objects, eight objects appear strong emission-line galaxies at
lower redshift; e.g., [O {\sc ii}] $\lambda$3727 emitters at $z \approx 0.54$,
H$\beta$ at $z \approx 0.18$, or [O {\sc iii}]$\lambda$5007 emitters at $z
\approx 0.15$. The remaining seven objects are unclassified because they are
too faint to be detected in broad-band images. We discuss observational
properties of these strong emission-line sources. In particular, our data allow
us to estimate the star formation density at $z \approx 3.7$ for the first
time.


title: Kinematics of diffuse elliptical galaxies

abstract:
  New observations show that most of the flattened diffuse elliptical (dE)
galaxies are essentially isotropic rotators. This supports the idea that dEs
have evolved from fast rotating dIrr systems or late-type spirals after their
gas was expelled by SN-driven winds and stripped by ram pressure against the
intergalactic medium.


title: Binary evolution and neutron stars in globular clusters

abstract:
  Improved observations of globular clusters are uncovering a large number of
radio pulsars and of X-ray sources. The latter include binaries in which a
neutron star or a white dwarf accretes matter from a companion, recycled
pulsars, and magnetically active binaries. Most of these sources originate from
close encounters between stars in the cluster core; magnetically active
binaries and some cataclysmic variables have evolved from primordial binaries.
The formation rate through close encounters scales differently with the central
density and core radius of the cluster than the probability for a single binary
to be perturbed by an encounter. This is exploited in some preliminary
observational tests of the close encounter hypothesis.
  Accreting black holes have been found in globular clusters with other
galaxies; the absence of such holes in the Milky Way clusters is compatible
with the small number expected.


title: Parameterising the third dredge-up in asymptotic giant branch stars

abstract:
  We present new evolutionary sequences for low and intermediate mass stars for
three different metallicities, Z = 0.02,0.008 and 0.004. We evolve the models
from the pre-main sequence to the thermally-pulsing asymptotic giant branch
phase. We have two sequences of models for each mass, one which includes mass
loss and one without mass loss. Typically 20 or more pulses have been followed
for each model, allowing us to calculate the third dredge-up parameter for each
case. Using the results from this large and homogeneous set of models, we
present an approximate fit for the core mass at the first thermal pulse, as
well as for the third dredge-up efficiency parameter, and the core mass at the
first third dredge-up episode as a function of metallicity and total mass. We
also examine the effect of a reduced envelope mass on the value of the third
dredge-up efficiency parameter.


title: The census of cataclysmic variables in the ROSAT Bright Survey

abstract:
  We give an identification summary and results of polarimetric, photometric
and spectroscopic follow-up observations of new, X-ray bright cataclysmic
variables. These were identified as optical counterparts of high galactic
latitude sources in the ROSAT All-Sky Survey. This optical identification
programme is termed the ROSAT Bright Survey (RBS) and represents the first
complete soft X-ray selected, flux-limited sample of CVs at high galactic
latitude (survey area ~20400 sq.deg.). The systems described here escaped
previous identification programmes since these surveys were designed to
identify even brighter than ours or particularly soft X-ray sources. Among the
11 new RBS-CVs we find 6 magnetic systems of AM Herculis type, 4 dwarf novae
(among them one candidate), and one particularly bright system of uncertain
nature, tentatively identified as dwarf nova or symbiotic binary. Orbital
periods could be determined for all magnetic systems which range from 87.1 min
to 187.7 min. Three of the new dwarf novae have moderate to high inclination
and two of them might be eclipsing. Using non-magnetic systems only we derive a
space density of CVs of ~3 10^{-5} pc^{-3}. This limit rests on the two new
nearby, low-luminosity systems RBS0490 and RBS1955, with estimated distances of
30pc only and luminosities below 10^{30} erg s^{-1}.


title: Cluster formation in the LMC

abstract:
  In this work we present preliminary results concerning the properties of
about 50 clusters and associations located in a densely populated region at the
Southern edge of the supershell LMC~4. The ages of the clusters and
associations are derived. The cluster formation rate peaks at about 10-20 Myr
ago corresponding to the age of the formation of LMC~4. Objects younger than 10
Myr are located close to CO clouds, indicating a possible trigger of the recent
star formation by the interaction of the supershell with the interstellar
medium.
  Isophotal analysis has been done for 50% of the clusters. A large number of
objects present isophotal distortions commonly interpreted as sign of
interaction. Cluster multiplets are coeval within 20 Myr, suggesting a common
origin. This indicates that clusters possibly form in large groups. Our
findings are in agreement with the unified view of multi-scale star formation,
where a size-duration correlation is expected.


title:
Construction optimale d'images bolometriques - Contribution a l'etude du
  milieu interstellaire et du rayonnement fossile

abstract:
  This work takes part of the development of far-infrared and millimeter
astrophysics. We have worked on the data processing and analysis in the fields
of the Galactic interstellar medium, through the dust thermal emission, and
cosmology through the observation of the cosmic microwave background
fluctuations. We have been particularly interested in optimal map-making by
inverse linear methods. We have developed a new map-making method for the
balloon-borne submillimeter experiment PRONAOS, based on a Wiener inversion
matrix, which allows to globally reconstruct the map. The analysis of PRONAOS
maps in massive star-forming complexes as Orion and M17 allowed us to discover
the large variations of the physical conditions and the dust properties. We
showed an anticorrelation between the temperature and the submillimeter
spectral index. Our investigations concerning this effect favour causes related
to the intrinsic physics of the grains. We have also developed optimal
map-making methods for the experiments aiming at measuring the cosmic microwave
background fluctuations. The iterative methods that we have developed allow to
reconstruct the sky maps very accurately, in spite of the large amount of
self-correlated noise present in the timelines. We have also worked on the data
processing and analysis for the Archeops balloon-borne experiment.


title: The [OII]3727 Luminosity Function of the Local Universe

abstract:
  The measurement of the Star Formation Rate density of the Universe is of
prime importance in understanding the formation and evolution of galaxies. The
[OII]3727 emission line flux, easy to measure up to z~1.4 within deep redshift
surveys in the optical and up to z~5.4 in the near infrared, offers a reliable
means of characterizing the star formation properties of high-z objects. In
order to provide the high-z studies with a local reference, we have measured
total [OII]3727 fluxes for the well analyzed local sample of star-forming
galaxies from the Universidad Complutense de Madrid Survey. This data is used
to derive the [OII]3727 luminosity function for local star-forming galaxies.
When compared with similar luminosity densities published for redshift up to
z~1, the overall evolution already observed in the star formation activity of
the Universe is confirmed.


title: Coupling parameters and the form of the potential via Noether symmetry

abstract:
  We explore the conditions for the existence of Noether symmetries in the
dynamics of FRW metric, non minimally coupled with a scalar field, in the most
general situation, and with nonzero spatial curvature. When such symmetries are
present we find general exact solution for the Einstein equations. We also show
that non Noether symmetries can be found.
  Finally,we present an extension of the procedure to the Kantowski- Sachs
metric which is particularly interesting in the case of degenerate Lagrangian.


title: The analysis of red giant branch photometry in galaxies

abstract:
  We present an analysis of the many possible methods for simulating and
analysing colour-magnitude diagrams, with application to studies of the field
halo stellar populations of resolved galaxies. Special consideration is made to
the analysis of stars on the Red Giant branch (RGB), and methods for obtaining
metallicity distributions for old populations based on analysis of evolved
sections of the Colour Magnitude Diagram (CMD). These tools are designed to
provide a reliable and accurate method for the analysis of resolved Population
II stars in the haloes of nearby galaxies. In particular, we introduce a
Perpendicular Distance method for calculating most likely source isochrones for
stars in our input dataset. This method is shown to have several advantages
over a more traditional approach considering the isochrone as a set of
finely-spaced Gaussian probability distributions. We also consider methods by
which the obtained metallicity distribution might be most efficiently optimised
and especially evaluate the difficulties involved in avoiding sub-optimal local
maxima in the likelihood maximisation procedure.


title:
Automated spectroscopic abundances of A and F-type stars using echelle
  spectrographs II. Abundances of 140 A-F stars from ELODIE and CORALIE

abstract:
  Using the method presented in Erspamer & North (2002, Paper I hereafter),
detailed abundances of 140 stars are presented. The uncertainties
characteristic of this method are presented and discussed. In particular, we
show that for a S/N ratio higher than 200, the method is applicable to stars
with a rotational velocity as high as 200 km/s. There is no correlation between
abundances and vsini, except a spurious one for Sr, Sc and Na which we explain
by the small number of lines of these elements combined with a locally biased
continuum. Metallic giants (Hauck 1986) show larger abundances than normal
giants for at least 8 elements: Al, Ca, Ti, Cr, Mn, Fe, Ni and Ba. The
anticorrelation for Na, Mg, Si, Ca, Fe and Ni with vsini suggested by Varenne
and Monier (1999) is not confirmed. The predictions of the Montreal models
(e.g. Richard et al. 2001) are not fulfilled in general. However a correlation
between [Fe/H] and logg is found for stars of 1.8 to 2.0 Mo. Various possible
causes are discussed, but the physical reality of this correlation seems
inescapable.


title: Arc Statistics in Cosmological Models with Dark Energy

abstract:
  We investigate how the probability of the formation of giant arcs in galaxy
clusters is expected to change in cosmological models dominated by dark energy
with an equation of state p=w rho c^2 compared to cosmological-constant or open
models. To do so, we use a simple analytic model for arc cross sections based
on the Navarro-Frenk-White density profile which we demonstrate reproduces
essential features of numerically determined arc cross sections. Since analytic
lens models are known to be inadequate for accurate absolute quantifications of
arc probabilities, we use them only for studying changes relative to
cosmological-constant models. Our main results are (1) the order of magnitude
difference between the arc probabilities in low density, spatially flat and
open CDM models found numerically is reproduced by our analytic model, and (2)
dark-energy cosmologies with w>-1 increase the arc optical depth by at most a
factor of two and are thus unlikely to reconcile arc statistics with spatially
flat cosmological models with low matter density.


title: Stacking Clusters in the ROSAT All-Sky Survey

abstract:
  Ongoing and planned wide-area surveys at optical and infrared wavelengths
should detect a few times 10^5 galaxy clusters, roughly 10% of which are
expected to be at redshifts >~ 0.8. We investigate what can be learned about
the X-ray emission of these clusters from the ROSAT All-Sky Survey. While
individual clusters at redshifts >~ 0.5 contribute at most a few photons to the
survey, a significant measurement of the mean flux of cluster subsamples can be
obtained by stacking cluster fields. We show that the mean X-ray luminosity of
clusters with mass M >~ 2 x 10^{14} M_sun/h selected from the Sloan Digital Sky
Survey should be measurable out to redshift unity with signal-to-noise >~ 10,
even if clusters are binned with Delta z=0.1 and Delta ln M ~ 0.3. For such
bins, suitably chosen hardness ratio allows the mean temperature of clusters to
be determined out to z ~ 0.7 with a relative accuracy of Delta T/T <~ 0.15 for
M > 10^{14} M_sun/h.


title: Cosmic Distances: Current Odds and Future Perspectives

abstract:
  We discuss recent theoretical and empirical results concerning cosmic
distances and discuss the problems affecting the Cepheid and the RR Lyrae
distance scales. In particular, we outline the key role that first overtone
Cepheids can play to improve the accuracy of distance determinations to nearby
galaxies. We also address the positive features of the K-band
Period-Luminosity-Metallicity (PLZ_K) relation of RR Lyrae stars when compared
to the M_V vs [Fe/H] relation. Moreover, we discuss the impact that accurate
multiband data in external galaxies can have on the evolutionary properties of
intermediate and low-mass stars. Finally, we introduce possible avenues of
future research in stellar astrophysics.


title: The dynamical Casimir effect and energetic sources for gamma ray bursts

abstract:
  On the analogy of the Casimir effect, we present an effect of quantum-field
fluctuations, attributed to gravitational field coupling to the zero-point
energy of virtual particles in the vacuum. In the process of black hole's
formation, such an effect could cause tremendous energy release, possibly
describing a scenario of energetic sources for observed gamma ray bursts.


title: Preliminary results from VLT (FORS1) photometry of NGC 6397

abstract:
  We present VLT (FORS1) photometry of the lower main sequence (MS) of the
Galactic Globular Cluster (GGC) NGC 6397, for stars located in 2 fields
extending from a region near the cluster center out to ~ 10'. The obtained CMD
shows a narrow MS extending down to V ~ 27 (figure c), much deeper than any
previous ground based study and comparable with previous HST photometry (Cool
et al. 1996). The comparison between observed MS Luminosity Functions (LFs)
derived for 2 annuli at different radial distance from the center of the
cluster shows a clear-cut correlation between their slope before reaching the
turn-over, and the radial position of the observed fields inside the cluster
area: the LFs become flatter with decreasing radius, a trend that is consistent
with the interpretation of NGC 6397 as a dynamically relaxed system.


title:
The Sizes of OH (1720 MHz) Supernova Remnant Masers: MERLIN and VLBA
  Observations of IC443

abstract:
  MERLIN and VLBA observations of the 1720 MHz maser emission from the OH
molecule in the supernova remnant IC443 are presented. Based on MERLIN data
with a resolution of 160 mas, the deconvolved sizes of the maser sources are in
the range 90 to 180 mas (135 to 270 AU). The 12 mas resolution VLBA images show
compact cores with sizes in the range 15 to 55 mas. The maser brightness
temperatures are (2-34)x10^6 K for the MERLIN sources and (5-19)x10^8 K for the
VLBA cores, in agreement with theory. Unlike the Zeeman Stokes V profiles
observed in other OH (1720 MHz) SNR masers, single-handed circular polarization
line profiles are observed in IC443 on all angular scales from 1000 to 10 mas
resolution. For one line component, the observed line width is 0.24+/-0.07
km/s, compared to an estimated Doppler width of 0.49 km/s. This discrepancy in
line widths can be accounted for if the maser emission arises from an elongated
ellipsoidal region of masing gas.


title:
The Extraordinary X-ray Light Curve of the Classical Nova V1494 Aquilae
  (1999 #2) in Outburst: The Discovery of Pulsations and a "Burst"

abstract:
  V1494 Aql (Nova Aql 1999 No. 2) was discovered on 2 December 1999. We
obtained Chandra ACIS-I spectra on 15 April and 7 June 2000 which appear to
show only emission lines. Our third observation, on 6 August, showed that its
spectrum had evolved to that characteristic of a Super Soft X-ray Source. We
then obtained Chandra LETG+HRC-S spectra on 28 September (8 ksec) and 1 October
(17 ksec). We analyzed the X-ray light curve of our grating observations and
found both a short time scale ``burst'' and oscillations. Neither of these
phenomena have previously been seen in the light curve of a nova in outburst.
The ``burst'' was a factor of 10 rise in X-ray counts near the middle of the
second observation, and which lasted about 1000 sec; it exhibited at least two
peaks, in addition to other structure. Our time series analysis of the combined
25 ksec observation shows a peak at 2500 s which is present in independent
analyses of both the zeroth order image and the dispersed spectrum and is not
present in similar analyses of grating data for HZ 43 and Sirius B. Further
analyses of the V1494 Aql data find other periods present which implies that we
are observing non-radial g+ modes from the pulsating, rekindled white dwarf.


title:
Infrared stellar populations in the central parts of the Milky Way
  galaxy

abstract:
  Near- and mid-IR survey data from DENIS and ISOGAL are used to investigate
the structure and formation history of the inner 10 degree (1.4 kpc) of the
Milky Way galaxy. Synthetic bolometric corrections and extinction coefficients
in the near- and mid-IR are derived for stars of different spectral types, to
allow the transformation of theoretical isochrones into observable
colour-magnitude diagrams. The observed IR colour-magnitude diagrams are used
to derive the extinction, metallicity and age for individual stars. The inner
galaxy is dominated by an old population (> 7 Gyr). In addition, an
intermediate-age population (200 Myr to 7 Gyr) is detected, which is consistent
with the presence of a few hundred Asymptotic Giant Branch stars with heavy
mass loss. Furthermore, young stars (< 200 Myr) are found across the inner
Bulge. The metallicities of these stellar population components are discussed.
These results can be interpreted in terms of an early epoch of intense star
formation and chemical enrichment which shaped the bulk of the Bulge and
nucleus, and a more continuous star formation history which gradually shaped
the disk from the accretion of sub-solar metallicity gas from the halo. A
possible increase in star formation about 200 Myr ago might have been triggered
by a minor merger. Ever since the formation of the first stars, mechanisms have
been at play that mix the populations from the nucleus, Bulge and disk.
Luminosity functions across the inner galactic plane indicate the presence of
an inclined (bar) structure at > 1 kpc from the galactic centre, near the inner
Lindblad resonance. The innermost part of the Bulge, within about 1 kpc from
the galactic centre, seems azimuthally symmetric.


title:
Modelling the Formation of Individual Galaxies: A Morphology Problem for
  CDM?

abstract:
  We use a semi-analytic model of halo formation to study the dynamical history
of giant field galaxies like the Milky Way. We find that in a concordance LCDM
cosmology, most isolated disk galaxies have remained undisturbed for 8-10 Gyr,
such that the age of the Milky Way's thin disk is unremarkable. Many systems
also have older disk components which have been thickened by minor mergers,
consistent with recent observations of nearby field galaxies. We do have a
considerable problem, however, reproducing the morphological mix of nearby
galaxies. In our fiducial model, most systems have disk-to-bulge mass ratios of
order 1, and look like S0s rather than spirals. This result depends mainly on
merger statistics, and is unchanged for most reasonable choices of our model
parameters. We discuss two possible solutions to this morphology problem in
LCDM.


title: Detection of a Collimated Jet towards a High-mass Protostar

abstract:
  Here we present the discovery of a triple radio continuum source associated
with IRAS 16547-4247. The spectral indices of the three components are
consistent with a jet powered by a massive O-type star in the process of
formation, with the outer radio components being the shocked gas at the working
surfaces of the jet. The detected radio continuum emission from the central
object is thought to arise from the jet itself, prior to the formation of a
detectable HII region. All three radio continuum components are located within
a molecular core of mass 10^3 M_sun. Our discovery makes IRAS 16547-4247 the
most luminous (6.2 x 10^4 L_sun) young stellar object from which a thermal jet
emanates, suggesting that the mechanism that produces jets in low-mass star
formation also operates in high-mass star formation.


title:
Extrasolar Planet Transit Light Curves and a Method to Select the Best
  Planet Candidates for Mass Follow-up

abstract:
  A unique analytical solution of planet and star parameters can be derived
from an extrasolar planet transit light curve under a number of assumptions.
This analytical solution can be used to choose the best planet transit
candidates for radial velocity follow-up measurements, with or without a known
spectral type. In practice, high photometric precision (< 0.005 mag) and high
time sampling (< 5 minutes) are needed for this method. See Seager &
Mallen-Ornelas (2002) for full details.


title: Wide-Field Surveys from the SNAP Mission

abstract:
  The Supernova/Acceleration Probe (SNAP) is a proposed space-borne observatory
that will survey the sky with a wide-field optical/near-infrared (NIR) imager.
The images produced by SNAP will have an unprecedented combination of depth,
solid-angle, angular resolution, and temporal sampling. For 16 months each, two
7.5 square-degree fields will be observed every four days to a magnitude depth
of AB=27.7 in each of the SNAP filters, spanning 3500-17000\AA. Co-adding
images over all epochs will give AB=30.3 per filter. In addition, a 300
square-degree field will be surveyed to AB=28 per filter, with no repeated
temporal sampling. Although the survey strategy is tailored for supernova and
weak gravitational lensing observations, the resulting data will support a
broad range of auxiliary science programs.


title: On the self-consistency of evolutionary synthesis models

abstract:
  Evolutionary synthesis models have been used to study the physical properties
of unresolved populations in a wide range of scenarios. Unfortunately, their
self-consistency are difficult to test and there are some theoretical open
questions without an answer: (1) The change of the homology relations assumed
in the computation of isochrones due to the effect of stellar winds (or
rotation) and the discontinuities in the stellar evolution are not considered.
(2) There is no a consensus about how the isochrones must be integrated. (3)
The discreteness of the stellar populations (that produce an intrinsic
statistical dispersion) usually are not taken into account, and model results
are interpreted in a deterministic way instead a statistical one... The
objective of this contribution is to present some inconsistencies in the
computation and some cautions in the application of the results of such codes.


title: Bars and Dark Matter Halo Cores

abstract:
  Self-consistent bars that form in galaxies embedded within cuspy halos are
unable to flatten the cusp. Short bars form in models with quasi-flat rotation
curves. They lose angular momentum to the halo through dynamical friction, but
the continuous concentration of mass within the disk as the bar grows actually
compresses the halo further, overwhelming any density reduction due to the
modest angular momentum transfer to the halo. Thus the Weinberg-Katz proposed
solution to the non-existence of the predicted cuspy halos from CDM simulations
would seem to be unworkable. I also find that the concerns over the performance
of N-body codes raised by these authors do not apply to the methods used here.


title:
Galaxy Populations and Evolution in Clusters III. The Origin of Low-Mass
  Galaxies in Clusters: Constraints from Stellar Populations

abstract:
  Low-mass galaxies in nearby clusters are the most numerous galaxy type in the
universe, yet their origin and properties remain largely unknown. To study
basic questions concerning these galaxies we present the results of a survey
designed to constrain the characteristics and properties of the stellar
populations in a magnitude complete sample of low-mass cluster galaxies (LMCGs)
in the center of the Perseus cluster. Using deep, high-quality WIYN UBR images,
we demonstrate that the 53 LMCGs in our sample have a significant scatter about
the color-magnitude relationship at M_B > -15. By comparing single-burst
stellar population models to our photometry, we argue that stellar populations
in LMCGs all have ages > 1 Gyrs, with redder LMCGs having stellar metallicities
[Fe/H] > -0.5. By assuming that the colors of LMCGs reflect metallicity, and
have co-evolved with the giant ellipticals, we find a wide range of values,
from solar to [Fe/H] ~ -3. We argue from this that LMCGs have multiple origins,
and fundamentally differ from Local Group dwarf spheroidals/ellipticals. The
inferred lower metallicities of the bluer LMCGs implies that these are possibly
primordial galaxies formed through self enrichment and stellar feedback
provided by winds from supernova. We also investigate several other formation
scenarios for these LMCGS, including: self enrichment induced by the
confinement of metals in halos by the intracluster medium, in situ formation
out of intracluster gas, systems with extreme dark halos, and as remnants of
higher mass systems. We conclude that roughly half of all low-mass cluster
galaxies have stellar populations and kinematic properties, discussed in
previous papers in this series, consistent with being the remnants of stripped
galaxies accreted into clusters a few Gyrs ago.


title:
Inner Structure of Protostellar Collapse Candidate B335 Derived from
  Millimeter-Wave Interferometry

abstract:
  We present a study of the density structure of the protostellar collapse
candidate B335 using continuum observations from the IRAM Plateau de Bure
Interferometer made at wavelengths of 1.2mm and 3.0mm. We analyze these data,
which probe spatial scales from 5000 AU to 500 AU, directly in the visibility
domain by comparison to synthetic observations constructed from models that
assume different physical conditions. This approach allows for much more
stringent constraints to be derived from the data than from analysis of images.
A single radial power law in density provides a good description of the data,
with best fit power law index p=1.65+/-0.05. Through simulations, we quantify
the sensitivity of this result to various model uncertainties, including
assumptions of temperature distribution, outer boundary, dust opacity spectral
index, and an unresolved central component. The largest uncertainty comes from
the unknown presence of a centralized point source. A point source with 1.2mm
flux of F=12+/-7 mJy reduces the density index to p=1.47+/-0.07. The remaining
sources of systematic uncertainty, the most important of which is the
temperature distribution, likely contribute a total uncertainty of < 0.2. We
therefore find strong evidence that the power law index of the density
distribution within 5000 AU is significantly less than the value at larger
radii, close to 2.0 from previous studies of dust emission and extinction.
These results conform well to the generic paradigm of isolated, low-mass star
formation which predicts a power law density index close to p=1.5 for an inner
region of gravitational free fall onto the protostar.


title: Formation of protostellar jets - effects of magnetic diffusion

abstract:
  We investigate the evolution of a disk wind into a collimated jet under the
influence of magnetic diffusivity, assuming that the turbulent pattern in the
disk will also enter the disk corona and the jet. Using the ZEUS-3D code in the
axisymmetry option we solve the time-dependent resistive MHD equations for a
model setup of a central star surrounded by an accretion disk. We find that the
diffusive jets propagate slower into the ambient medium. Close to the star we
find that a quasi stationary state evolves after several hundred (weak
diffusion) or thousand (strong diffusion) disk rotations. Magnetic diffusivity
affects the protostellar jet structure as follows. The jet poloidal magnetic
field becomes de-collimated. The jet velocity increases with increasing
diffusivity, while the degree of collimation for the hydrodynamic flow remains
more or less the same. We suggest that the mass flux is a proper tracer for the
degree of jet collimation and find indications of a critical value for the
magnetic diffusivity above which the jet collimation is only weak.


title:
Detection of small scale fluctuations in the near-IR cosmic infrared
  background from long exposure 2MASS fields

abstract:
  We report first results for the cosmic infrared background (CIB) fluctuations
at 1.25, 1.65 and 2.17 micron obtained from long exposures constructed from
2MASS standard star fields. We have co-added and analyzed scans from one such
field with a total exposure time > 1 hour, and removed sources and other
artifacts. The stars and galaxies were clipped out to K_s~19^m leaving only
high-z galaxies (or possibly local low-surface-brightness systems). The
residual component of the diffuse emission on scales from a few arc-sec to a
few arc-min has a power-law slope consistent with emission produced by
clustered galaxies. The noise (and residual artifacts) contribution to the
signal is small and the colors of the signal are very different from Galactic
stars or air-glow. We therefore identify the signal as CIB fluctuations from
the faint unresolved galaxies. We show that the present-day galaxies with no
evolution would produce a significant deficit in the observed CIB fluctuations.
Thus the dominant contribution to the observed signal must come from high z and
may indicate high rates of star formation at those epochs.


title:
Analysis of the diffuse near-IR emission from 2MASS deep integration
  data: foregrounds vs the cosmic infrared background

abstract:
  This is one of two papers in which we report the detection of structure in
the cosmic infrared background (CIB) between 1.25 - 2.2 micron through the use
of data from the Two Micron Sky Survey (2MASS). This paper concentrates on data
assembly, analysis and the estimate of the various foreground contributions;
the companion paper (Kashlinsky, Odenwald, Mather, Skrutskie, Cutri 2002,
hereafter KOMSC) presents the cosmological results for the CIB fluctuations and
their implications. By using repeated observations of a specific calibration
star field, we were able to achieve integration times in excess of 3900 seconds
compared to the 7.8 seconds in the standard 2MASS data product. This yielded a
point source detection limit (3 \sigma) of +18.5^m in K_s band. The resulting
co-added images were processed to remove point sources to a limiting surface
brightness of +20^m/arcsec$^2 or 40 nW/m^2/sr. The remaining maps contained
over 90% of the pixels and were Fourier transformed to study the spatial
structure of the diffuse background light. After removing resolved sources and
other artifacts, we find that the power spectrum of the final images has a
power-law distribution consistent with clustering by distant galaxies. We
estimate here the contributions to this signal from Galactic foregrounds,
atmospheric OH-glow, zodiacal light and instrument noise, all of which are
small and of different slopes. Hence, this supports the KOMSC identification of
the signal as coming from the CIB fluctuations produced by distant clustered
galaxies.


title: Gravitational microlensing as a test of stellar model atmospheres

abstract:
  We present calculations illustrating the potential of gravitational
microlensing to discriminate between classical models of stellar surface
brightness profiles and the recently computed ``Next Generation'' models of
Hauschildt et al. These spherically-symmetric models include a much improved
treatment of molecular lines in the outer atmospheres of cool giants -- stars
which are very typical sources in Galactic bulge microlensing events. We show
that the microlensing signatures of intensively monitored point and fold
caustic crossing events are readily able to distinguish between NextGen and the
classical models, provided a photometric accuracy of 0.01 magnitudes is
reached. This accuracy is now routinely achieved by alert networks, and hence
current observations can discriminate between such model atmospheres, providing
a unique insight on stellar photospheres.


title:
Calculations of the Far-Wing Line Profiles of Sodium and Potassium in
  the Atmospheres of Substellar-Mass Objects

abstract:
  At the low temperatures achieved in cool brown dwarf and hot giant planet
atmospheres, the less refractory neutral alkali metals assume an
uncharacteristically prominent role in spectrum formation. In particular, the
wings of the Na-D (5890 \AA) and K I (7700 \AA) resonance lines come to define
the continuum and dominate the spectrum of T dwarfs from 0.4 to 1.0 \mic.
Whereas in standard stellar atmospheres the strengths and shapes of the wings
of atomic spectral lines are rarely needed beyond 25 \AA of a line center, in
brown dwarfs the far wings of the Na and K resonance lines out to 1000's of \AA
detunings are important. Using standard quantum chemical codes and the Unified
Franck-Condon model for line profiles in the quasi-static limit, we calculate
the interaction potentials and the wing line shapes for the dominant Na and K
resonance lines in H$_2$- and helium-rich atmospheres. Our theory has natural
absorption profile cutoffs, has no free parameters, and is readily adapted to
spectral synthesis calculations for stars, brown dwarfs, and planets with
effective temperatures below 2000 Kelvin.


title: An Integral Field Spectrograph for SNAP Supernova Identification

abstract:
  A well-adapted spectrograph concept has been developed for the SNAP
(SuperNova/Acceleration Probe) experiment. The goal is to ensure proper
identification of Type Ia supernovae and to standardize the magnitude of each
candidate by determining explosion parameters. An instrument based on an
integral field method with the powerful concept of imager slicing has been
designed and is presented in this paper. The spectrograph concept is optimized
to have very high efficiency and low spectral resolution (R~100), constant
through the wavelength range (0.35-1.7 microns), adapted to the scientific
goals of the mission.


title: Multitransitional observations of the CS core of L673

abstract:
  A multitransitional study with the BIMA interferometric array was carried out
toward the starless core found in the L673 region, in order to study the
small-size structure of the cores detected with previous single--dish
observations, which provides us with a test of the predictions of the chemical
model of Taylor et al. (1996; 1998). We detected emission in the CS (2-1), N2H+
(1-0), and HCO+ (1-0) lines. Several clumps of size ~0.08 pc were found for
each line distributed all over the region where previous single-dish emission
was found (Morata et al. 1997). Each molecular transition traces differently
the clump distribution, although in some cases the detected clumps are
coincident. The distribution of the N2H+ emission and the single-dish NH3
emission are coincident and compatible with an origin in the same gas. The
large fraction of missing flux measured for the CS (2-1) transition can be
explained if the cloud is formed by a clumpy and heterogeneous medium. Four
positions were selected to derive the abundance ratios [N2H+/CS] and [HCO+/CS]
from the molecular column density determinations, and to compare them with the
values predicted by the chemical model. The model was able to explain the
interferometric observations, and, in particular, the chemical differentiation
of the detected clumps and the coincidence of the NH3 and N2H+ emissions. The
lack of HCO+ towards the two selected positions that trace the more evolved
clumps cannot be accounted for by the model, but it is possibly due to strong
self-absorption. We propose a classification of the studied clumps according to
the stage of chemical evolution indicated by the molecular abundances.


title: Isolating Clusters with Wolf-Rayet Stars in I Zw 18

abstract:
  We present UV images and spectra of the starburst galaxy I Zw 18, taken with
the Space Telescope Imaging Spectrograph. The high spatial resolution of these
data allows us to isolate clusters containing Wolf-Rayet stars of the subtype
WC. Our far-UV spectra clearly show CIV 1548,1551 and HeII 1640 emission of WC
stars in two clusters: one within the bright (NW) half of I Zw 18, and one on
the outskirts of this region. The latter spectrum is unusual, because the CIV
is seen only in emission, indicating a spectrum dominated by WC stars. These
data also demonstrate that the HI column in I Zw 18 is strongly peaked in the
fainter (SE) half of I Zw 18, with a column depth far larger than that reported
in previous analyses.


title: WKB approximation for inflationary cosmological perturbations

abstract:
  A new method for predicting inflationary cosmological perturbations, based on
the Wentzel-Kramers-Brillouin (WKB) approximation, is presented. A general
expression for the WKB scalar and tensor power spectra is derived. The main
advantage of the new scheme of approximation is that it is valid even if the
slow-roll conditions are violated. The method is applied to power-law
inflation, which allows a comparison with an exact result. It is demonstrated
that the WKB approximation predicts the spectral indices exactly and the
amplitude with an error lower than 10%, even in regimes far from
scale-invariance. The new method of approximation is also applied to a
situation where the slow-roll conditions hold. It is shown that the result
obtained bears close resemblance with the standard slow-roll calculation.
Finally, some possible improvements are briefly mentioned.


title: Wide-field cosmic shear surveys

abstract:
  We present the current status of cosmic shear based on all surveys done so
far. Taken together, they cover more about 70 deg$^2$ and concern more than 3
million galaxies with accurate shape measurement. Theoretical expectations,
observational results and their cosmological interpretations are discussed in
the framework of standard cosmology and CDM scenarios. The potentials of the
next generation cosmic shear surveys are discussed.


title: Extreme emission line outflows in the GPS source 4C 12.50 (PKS 1345+12)

abstract:
  We present high resolution spectra (0.7 A/pix) of the GPS source 4C 12.50
with large spectral coverage (~ 4500A) taken with the 4.2m William Herschel
Telescope on La Palma. The slit was aligned along PA 160 to include the nucleus
and emission line region to the NW. An asymmetric halo extending 20 kpc NW and
12 kpc SE from the nucleus is clearly seen. At the position of the nucleus we
observe unusually broad forbidden emission line components (broadest component:
FWHM ~ 2000 km s^-1), blue shifted by up to 2000 km s^-1 with respect to the
halo of the galaxy and HI absorption. We interpret this as material in outflow.
We measure E(B-V) = 1.44 for the broadest, most kinematically disturbed
component, corresponding to an actual Hbeta flux 130 times brighter than that
measured. We calculate an upper limit for the mass of the line emitting gas of
order 10^6 solar masses for both the intermediate and broad components. Our
results are consistent with 4C 12.50 being a young radio source.


title: Prospects for weak lensing/cosmic shear with VLTs

abstract:
  The present status of weak lensing analyses of clusters of galaxies and of
cosmic shear surveys are presented and discussed. We focus on the impact of
very large telescopes on present-day and future surveys and compare their
potential with HST or wide field 4 meter telescopes.


title: Disk galaxy evolution: from the Milky Way to high-redshift disks

abstract:
  We develop a detailed model of the Milky Way (a ``prototypical'' disk galaxy)
and extend it to other disks with the help of some simple scaling relations,
obtained in the framework of Cold Dark Matter models. This phenomenological
(``hybrid'') approach to the study of disk galaxy evolution allows us to
reproduce successfully a large number of observed properties of disk galaxies
in the local Universe and up to redshift z~1. The important conclusion is that,
on average, massive disks have formed the bulk of their stars earlier than
their lower mass counterparts: the ``star formation hierarchy'' has been
apparently opposite to the ``dark matter assembly'' hierarchy. It is not yet
clear whether ``feedback'' (as used in semi-analytical models of galaxy
evolution) can explain that discrepancy.