title:
Subaru High-Dispersion Spectroscopy of Narrow-Line Region in the Seyfert
  Galaxy NGC 4151

abstract:
  We report on a study of forbidden emission-line spectrum of nearby Seyfert
1.5 galaxy NGC 4151 based on the high-resolution (R ~ 45,000) optical spectrum
obtained by using the High Dispersion Spectrograph boarded on the Subaru
Telescope. The profile parameters such as the emission-line widths, the
velocity shifts from the recession velocity of the host galaxy, and the
asymmetry indices, for emission lines including very faint ones such as [Ar
IV]4712,4740 and [Fe VI]5631,5677 are investigated. Statistically significant
correlations between the measured profile parameters and the critical densities
of transitions are found while there are no meaningful correlations between the
profile parameters and the ionization potentials of ions. By comparing the
results with photoionization model calculations, we remark that a simple
power-law distribution of the gas density which is independent of the radius
from the nucleus cannot explain the observed correlation between the
emission-line widths and the critical densities of the transitions. Taking the
additional dense gas component expected to exist at the innermost of the
narrow-line region into account, the observed correlations between the
emission-line width and the critical density of the transitions can be
understood since high-critical-density emission lines can arise at such
relatively inner regions even if their ionization potentials are low. The
observed correlation between the blueshift amounts of emission lines and the
critical densities of the ions is also explained if such dense gas clouds
located closer to the nucleus have larger outflowing velocities.


title:
Particle Acceleration in Supernova Remnants in the Presence of Streaming
  Instability and Nonlinear Wave Interactions

abstract:
  The instability in the cosmic-ray (CR) precursor of a SN shock is studied.
The level of turbulence in this region determines the maximum energy of
accelerated CRs. The consideration is not limited by the case of weak
turbulence. It is assumed that Kolmogorov type nonlinear wave interactions
together with the ion-neutral collisions restrict the amplitude of random
magnetic field. As a result, the maximum energy of accelerated particles
strongly depends on the age of a SNR. It can be as high as $10^{17}Z$ eV in
young SNR and falls down to about $10^{10}Z$ eV at the end of Sedov stage ($Z$
is the particle charge). This finding may explain why the SNRs with the age
more than a few thousand years are not prominent sources of very high energy
$\gamma $-rays. The averaged spectrum of ultrarelativistic CR injected in the
interstellar medium is close or somewhat steeper than $E^{-2}$.


title:
Spectral evolution of the microquasar XTE J1550-564 over its entire 2000
  outburst

abstract:
  We report on RXTE observations of the microquasar XTE J1550-564 during a ~70
day outburst in April-June 2000. We study the evolution of the PCA+HEXTE
spectra over the outburst. The source transited from an initial Low Hard State
(LS), to an Intermediate State (IS), and then back to the LS. The source shows
an hysteresis effect similar to what is observed in other sources, favoring a
common origin for the state transitions in soft X-ray transients. The first
transition occurs at a ~ constant 2-200 keV flux, which probably indicates a
change in the relative importance of the emitting media. The second transition
is more likely driven by a drop in the mass accretion rate.
  In both LS, the spectra are characterized by the presence of a strong
power-law tail (Compton corona) with a variable high energy cut-off. During the
IS, the spectra show the presence of a ~0.8 keV thermal component (accretion
disk). We discuss the apparently independent evolution of the two media, and
show that right after the X-ray maximum on MJD 51662, the decrease of the
source luminosity is due to a decrease of the power-law luminosity, at a
constant disk luminosity. This, together with the detection of radio emission
(with a spectrum typical of optically thin synchrotron emission), may suggest
that the corona is ejected and further detected as a discrete radio ejection.


title:
Gravitation in the fractal D=2 inertial universe: New phenomenology in
  spiral discs and a theoretical basis for MOND

abstract:
  An interpretation of Mach's Principle led us to consider if it was possible
to have a globally inertial universe that was irreducibly associated with a
non-trivial global matter distribution, Roscoe (GRG,2002,34,5,577-602,
astro-ph/0107397). This question received a positive answer, subject to the
condition that the global matter distribution is necessarily fractal, D=2. The
purpose of the present paper is to show how general gravitational processes
arise in this universe. We illustrate the theory by using it to model an
idealized spiral galaxy. One particular subclass of solutions, corresponding to
logarithmic spirals, has already been extensively tested in Roscoe
A&A,1999,343,788-800 (astro-ph/0107305), and shown to resolve dynamical data
over large samples of ORCs with a very high degree of statistical precision.
However, this latter analysis led directly to the discovery of a major new
phenomenology in spiral discs - that of discrete dynamical classes -
comprehensively confirmed in Roscoe A&A,2002,385,431-453 (astro-ph/0107300)
over four large independent samples of ORCs. In this paper, we analyse the
theory to show how the discrete dynamical classes phenomenology has a ready
explanation in terms of an algebraic consistency condition which must
necessarily be satisfied. Of equal significance, we apply the theory with
complete success to the detailed modelling of a sample of eight Low Surface
Brightness spirals (LSBs) which, hitherto, have been succesfully modelled only
by Milgrom's MOND algorithm. We are able to conclude that the essence of the
MOND algorithm must be contained within the presented theory.


title: Observational constraints on particle production during inflation

abstract:
  Resonant particle production, along with many other physical processes which
change the effective equation of state (EOS) during inflation, introduces a
step-like feature in the primordial power spectrum. We calculate observational
constraints on resonant particle production, parameterised in form of an
effective step height, N_eff and location in k-space, k_break. Combining data
from the cosmic microwave background and the 2dF Galaxy Redshift Survey yields
strong constraints in some regions of parameter space, although the range in
k-space which can be probed is restricted to k ~ 0.001 - 0.1 h Mpc^-1. We also
discuss the implications of our findings for general models which change the
effective EOS during inflation.


title:
Three-dimensional photoionisation modelling of the hydrogen-deficient
  knots in the planetary nebula Abell 30

abstract:
  We have constructed a photoionization model, using the 3-D Monte Carlo code
MOCASSIN for one of the hydrogen-deficient knots (J3) of the born-again
planetary nebula Abell 30. The model consists of spherical knots, comprising a
cold, dense, hydrogen-deficient core with very high metal abundances. The inner
core is surrounded by a less dense hydrogen-deficient and metal-enriched gas
envelope, with less extreme abundances. The envelope of the knot might have
been formed by the mixing of the knot material with the surrounding nebular
gas. This bi-chemistry, bi-density model did not produce enough heating to
match the fluxes of the collisionally excited emission lines (CELs) and of the
optical recombination lines (ORLs) observed in the spectrum of the knot. We
therefore included heating by photoelectric emission from dust grains in the
thermal equilibrium calculations, and found that dust-to-gas ratios of 0.077
and 0.107 by mass for the central core and the envelope of the knot,
respectively, are sufficient to fit the spectrum. Surprisingly, photoelectric
emission from grains is the dominant source of heating in the hot envelope of
the knot, while heating by photoionization of helium and heavy elements
dominates in the cold core. The chemical abundances inferred from our modelling
indicate, in agreement with the empirical analysis of Wesson et al. (2003),
that the C/O ratio in the two regions of the knot is less than unity, contrary
to theoretical predictions for born-again nebulae.


title:
New VI photometry of the sdOB binary AA Dor and an improved photometric
  model

abstract:
  New VI CCD photometry, obtained with integration times of 20s, of the
sdOB+degenerate-dwarf eclipsing binary system AA Dor has provided new complete
light curves with an rms scatter about a mean curve of +/-0.004 mag. These data
are analysed with an improved Light2 light curve synthesis code to yield more
accurate determinations of the radii of both stars, the orbital inclination,
and the flux ratio between the two components. These radii are only a little
different from the values derived 25 years ago from less complete data, but the
uncertainties on these values are improved by a factor of two. The apparent
discrepancy remains between the surface gravity of the sdOB primary star
obtained from the light-curve solution with the published spectroscopic orbit
and that obtained from NLTE analysis of high-resolution spectra of the sdOB
star. The substantial reflection effect in the system is adequately represented
by the Light2 code with a bolometric albedo of unity in light curves extending
from 0.35 microns to 2.2 microns. However there are differences at individual
wavelengths in the derived albedo, which may indicate redistribution of flux
from shorter wavelengths into the V and I passbands.


title: The distance and radius of the neutron star PSR B0656+14

abstract:
  We present the result of astrometric observations of the radio pulsar PSR
B0656+14, made using the Very Long Baseline Array. The parallax of the pulsar
is pi = 3.47 +- 0.36 mas, yielding a distance of 288 +33 -27 pc. This
independent distance estimate has been used to constrain existing models of
thermal x-ray emission from the neutron star's photosphere. Simple blackbody
fits to the x-ray data formally yield a neutron star radius R_inf ~ 7-8.5 km.
With more realistic fits to a magnetized hydrogen atmosphere, any radius
between ~13 and ~20 km is allowed.


title: The EDELWEISS experiment and Dark Matter Direct Detection

abstract:
  This mini-review first introduces the motivations for Dark Matter Searches.
The experimental aspect of the direct detection of Weakly Interactive Massive
Particles (WIMPs) is described, detailing its principle and presenting some
experiments with their recent results. The EDELWEISS experiment and its results
are discussed in more details before concluding with the future direct
detection experiments.


title: Catching NGC 4051 in the low state with Chandra

abstract:
  We report the results from a Chandra TOO observation of the low-luminosity
Narrow Line Seyfert 1 galaxy NGC 4051, obtained during a 6-week duration
low-flux state in 2001 February. During the Chandra observation, the 2-10 keV
source flux was 7e-12 erg/cm^2/s, corresponding to a 2-10 keV luminosity of
8e40 erg/s. We confirm the absence of strong extended soft X-ray emission in
NGC 4051, and that the low state spectrum is dominated by the central point
source. The X-ray spectrum has an unusual, hybrid shape, very soft below ~3 keV
(and which we model with a black body of temperature 0.14 keV) and very hard at
higher energies (power-law slope of Gamma~1). The lightcurves in both soft and
hard bands are significantly variable and correlated, implying a connection
between hard and soft components and proving that the hard component is
dominated by primary continuum emission and is not due to pure reflection from
distant cold material. However, a comparison with RXTE data obtained during the
same 2001 low state suggests the presence of unusually prominent disk
reflection features, which may help to explain the apparent upwards curvature
and extreme hardness of the Chandra spectrum above a few keV. The shape of the
2001 low state spectrum is consistent with that observed in a brief (<3 d) low
flux excursion during the source's normal state in April 2000, suggesting that
emission processes during the low state are not significantly different to
those in the normal state. The unusual spectral shape observed in the low state
may be a continuation to low fluxes of the normal, flux-dependent spectral
variability of the source.


title: A pulsar-atmosphere model for PSR 0656+14

abstract:
  We present a pulsar-atmosphere (PA) model for modulated thermal X-ray
emission from cooling magnetized neutron stars. The model synthesizes the
spectral properties of detailed stellar atmosphere calculations with the
non-uniform surface properties anticipated for isolated, aging radio pulsars,
and general relativistic effects on photon trajectories. We analyze the
archival Chandra observations of the middle-aged radio pulsar PSR 0656+14 with
the PA model and find it is an excellent representation of the phase-averaged
X-ray spectrum for a broad range of polar effective temperature T_p and column
density N_H ~ 10^{20} cm^{-2}. The spectral fits favor a sub-solar neutron star
mass M < 1.0 M_{\sun}, a large radius R=15-16 km for a source distance d ~ 190
pc, while retaining consistency with theoretical neutron star
equations-of-state. The modulated spectrum constrains the angular displacement
of the pulsar spin axis to 30 +/- 2 \arcdeg with respect to the line of sight.


title: Decoupling, Trans-Planckia and Inflation

abstract:
  We survey recent calculations probing what constraints decoupling can put on
the influence of very-high-energy physics on the predictions of inflation for
the cosmic microwave background. Using garden-variety hybrid inflation models
we identify two ways in which higher-energy physics can intrude into
inflationary predictions. 1. Non-adiabatic physics up to 30 e-foldings before
horizon exit can have observable consequences for the CMB, including the
introduction of features in the fluctuation spectrum at specific multipoles and
a general suppression of power at large scales (a prediction which was made
before the recent release of WMAP results). Our comparison of simple models
with the data marginally improves the goodness of fit compared to the standard
concordance cosmology, but only at the 1.5-sigma level. 2. Adiabatic physics
can also affect inflationary predictions through virtual loops of very-heavy
particles, but these can only be distinguished from lower-energy effects within
the context of specific models. We believe our conclusions should apply equally
well to trans-Planckian physics provided only that this physics satisfies
decoupling, such as string theory appears to do. (Non-decoupling
trans-Planckian proposals must explain why meaningful theoretical predictions
at low energies are possible at all.)


title: Stellar Hydrodynamics in Radiative Regions

abstract:
  We present an analysis of the response of a radiative region to waves
generated by a convective region of the star; this wave treatment of the
classical problem of ``overshooting'' gives extra mixing relative to the
treatment traditionally used in stellar evolutionary codes. The interface
between convectively stable and unstable regions is dynamic and nonspherical,
so that the nonturbulent material is driven into motion, even in the absence of
``penetrative overshoot.'' These motions may be described by the theory of
nonspherical stellar pulsations, and are related to motion measured by
helioseismology. Multi-dimensional numerical simulations of convective flow
show puzzling features which we explain by this simplified physical model.
Gravity waves generated at the interface are dissipated, resulting in slow
circulation and mixing seen outside the formal convection zone. The approach
may be extended to deal with rotation and composition gradients. Tests of this
description in the stellar evolution code TYCHO produce carbon stars on the
asymptotic giant branch (AGB), an isochrone age for the Hyades and three young
clusters with lithium depletion ages from brown dwarfs, and lithium and
beryllium depletion consistent with observations of the Hyades and Pleiades,
all without tuning parameters. The insight into the different contributions of
rotational and hydrodynamic mixing processes could have important implications
for realistic simulation of supernovae and other questions in stellar
evolution.


title:
The signature of substructure on gravitational lensing in the LCDM
  cosmological model

abstract:
  We present a study of the lens properties of quadruply imaged systems, lensed
by numerically simulated galaxies. We investigate a simulated elliptical and
disc galaxy drawn from high resolution simulations of galaxy formation in a
concordance $\Lambda$CDM universe. The simulations include the effects of gas
dynamics, star formation and feedback processes. Flux-ratio anomalies observed
in strong gravitational lensing potentially provide an indicator for the
presence of mass substructure in lens galaxies as predicted from CDM
simulations. We particularly concentrate on the prediction that, for an ideal
cusp caustic, the sum of the signed magnifications of the three highly
magnified images should vanish when the source approaches the cusp. Strong
violation of this cusp relation indicates the presence of substructure,
regardless of the global, smooth mass model of the lens galaxy. We draw the
following conclusions: (1) the level of substructure present in simulations
produces violations of the cusp relation comparable to those observed, (2)
higher-order catastrophes (e.g. swallowtails) can also cause changes of the
order of 0.6 in the cusp relation as predicted by a smooth model, (3) the flux
anomaly distribution depends on the image parity and flux and both the
brightest minimum and saddle-point images are more affected by substructure
than the fainter images. In addition, the brightest saddle point is demagnified
w.r.t. the brightest minimum. Our results are fully numerical and properly
include all mass scales, without making semi-analytic assumptions. They are
ultimately limited by the mass resolution of single particles in the simulation
determined by current computational limits, however show that our results are
not affected by shot-noise due to the finite number of particles.


title: New Dimensions in Cosmic Lensing

abstract:
  I review the current status of combing weak gravitational lensing with depth
information from redshifts as a direct probe of dark matter and dark energy in
the Universe. In particular I highlight: (1) The first maximum likelihood
measurement of the cosmic shear power spectrum, with the COMBO17 dataset (Brown
et al 2003); (2) A new method for mapping the 3-D dark matter distribution from
weak shear, and its first application to the COMBO17 dataset (Taylor et al
2003); (3) A new method for measuring the Dark Energy of the Universe using
purely the geometry of gravitational lensing, based on cross-correlation
tomography (Jain & Taylor 2003). I show that this method can constrain the
equation of state of the universe and its evolution to a few percent accuracy.


title: Observational Clues to Brown Dwarf Origins

abstract:
  Over the past year, we have conducted a multi-faceted program to investigate
the origin and early evolution of brown dwarfs. Using high-resolution Keck
optical spectra of ~30 objects near and below the sub-stellar boundary in
several star-forming regions, we present compelling evidence for a T Tauri-like
accretion phase in young brown dwarfs. Our systematic study of infrared L'-band
(3.8-micron) disk excess in ~50 spectroscopically confirmed young very low mass
objects reveal that a significant fraction of brown dwarfs harbor disks at a
very young age. Their inner disk lifetimes do not appear to be vastly different
from those of disks around T Tauri stars. Taken together, our findings are
consistent with a common origin for most low-mass stars, brown dwarfs and
isolated planetary mass objects.


title:
The CFHT Open Star Cluster Survey. IV. Two Rich, Young Open Star
  Clusters: NGC 2168 (M35) and NGC 2323 (M50)

abstract:
  We continue our study of rich Galactic clusters by presenting deep CCD
observations of both NGC 2168 (M35) and NGC 2323 (M50). Both clusters are found
to be rich (NGC 2168 contains at least 1000 stars brighter than V = 22 and NGC
2323 contains approximately 2100 stars brighter than our photometric limit of V
= 23) and young (age of NGC 2168 = 180 Myrs, age of NGC 2323 = 130 Myrs). The
color-magnitude diagrams for the clusters exhibit clear main sequences
stretching over 14 magnitudes in the V, B-V plane. Comparing these long main
sequences with those of earlier clusters in the survey, as well as with the
Hyades, has allowed for accurate distances to be established for each cluster
(dist. of NGC 2168 = 912 +/- 70/65 pc, dist. of NGC 2323 = 1000 +/- 81/75 pc).
Analysis of the luminosity and mass functions suggest that despite their young
ages, both clusters are somewhat dynamically relaxed exhibiting signs of
mass-segregation. This is especially interesting in the case of NGC 2323, which
has an age of only 1.3 times the dynamical relaxation time. The present
photometry is also deep enough to detect all of the white dwarfs in both
clusters. We discuss some interesting candidates which may be the remnants of
quite massive (M > 5 Mo) progenitor stars. The white dwarf cooling age of NGC
2168 is found to be in good agreement with the main-sequence turn-off age.
These objects are potentially very important for setting constraints on the
white dwarf initial-final mass relationship and upper mass limit for white
dwarf production.


title:
A Comparison of Measured Crab and Vela Glitch Healing Parameters with
  Predictions of Neutron Star Models

abstract:
  There are currently two well-accepted models that explain how pulsars exhibit
glitches, sudden changes in their regular rotational spin-down. According to
the starquake model, the glitch healing parameter, Q, which is measurable in
some cases from pulsar timing, should be equal to the ratio of the moment of
inertia of the superfluid core of a neutron star (NS) to its total moment of
inertia. Measured values of the healing parameter from pulsar glitches can
therefore be used in combination with realistic NS structure models as one test
of the feasibility of the starquake model as a glitch mechanism. We have
constructed NS models using seven representative equations of state of
superdense matter to test whether starquakes can account for glitches observed
in the Crab and Vela pulsars, for which the most extensive and accurate glitch
data are available. We also present a compilation of all measured values of Q
for Crab and Vela glitches to date which have been separately published in the
literature. We have computed the fractional core moment of inertia for stellar
models covering a range of NS masses and find that for stable NSs in the
realistic mass range 1.4 +/- 0.2 solar masses, the fraction is greater than
0.55 in all cases. This range is not consistent with the observational
restriction Q < 0.2 for Vela if starquakes are the cause of its glitches. This
confirms results of previous studies of the Vela pulsar which have suggested
that starquakes are not a feasible mechanism for Vela glitches. The much larger
values of Q observed for Crab glitches (Q > 0.7) are consistent with the
starquake model predictions and support previous conclusions that starquakes
can be the cause of Crab glitches.


title: Cosmic Ray Acceleration by Stellar Associations? The Case of Cygnus OB2

abstract:
  The origins of all extra-solar cosmic rays -- both the ultra high-energy and
lower energy Galactic variety -- remain unclear. It has been argued that the
large scale shocks and turbulence induced by the multiple interacting
supersonic winds from the many hot stars in young stellar associations may play
a role in accelerating Galactic cosmic rays -- with or without the associated
multiple supernova remnants (eg. Cesarsky & Montmerle, 1983; Bykov 2001). In
this context, the report by the HEGRA Cherenkov telescope group of a steady and
extended unidentified TeV gamma-ray source lying at the outskirts of Cygnus OB2
is particularly significant. This is the most massive stellar association known
in the Galaxy, estimated to contain ~2600 OB type members alone indeed, Cyg OB2
also coincides with the non-variable MeV-GeV range unidentified EGRET source,
3EG 2033+4118. We summarise here the near-simultaneous follow-up observations
of the extended TeV source region with the CHANDRA X-ray Observatory and the
Very Large Array (VLA) radio telescope. Applying a numerical simulation which
accurately tracks the radio to gamma-ray emission from primary hadrons as well
as primary and secondary e+/-, we find that the broadband spectrum of the TeV
source region favors a predominantly nucleonic rather than electronic origin of
the high-energy flux, though deeper X-ray and radio observations will help
confirm this. A very reasonable, ~0.1%, conversion efficiency of Cyg OB2's
extreme stellar wind mechanical luminosity to nucleonic acceleration to ~PeV
(10^15 eV) energies is sufficient to explain the multifrequency emissions.


title: Dynamical evolution of planetesimals in protoplanetary disks

abstract:
  The current picture of terrestrial planet formation relies heavily on our
understanding of the dynamical evolution of planetesimals -- asteroid-like
bodies thought to be planetary building blocks. In this study we investigate
the growth of eccentricities and inclinations of planetesimals in spatially
homogeneous protoplanetary disks using methods of kinetic theory. We explore
disks with a realistic mass spectrum of planetesimals evolving in time, similar
to that obtained in self-consistent simulations of planetesimal coagulation. We
calculate the behavior of planetesimal random velocities as a function of the
planetesimal mass spectrum both analytically and numerically; results obtained
by the two approaches agree quite well. Scaling of random velocity with mass
can always be represented as a combination of power laws corresponding to
different velocity regimes (shear- or dispersion-dominated) of planetesimal
gravitational interactions. For different mass spectra we calculate
analytically the exponents and time dependent normalizations of these power
laws, as well as the positions of the transition regions between different
regimes. It is shown that random energy equipartition between different
planetesimals can only be achieved in disks with very steep mass distributions
(differential surface number density of planetesimals falling off steeper than
m^{-4}), or in the runaway tails. In systems with shallow mass spectra
(shallower than m^{-3}) random velocities of small planetesimals turn out to be
independent of their masses. We also discuss the damping effects of inelastic
collisions between planetesimals and of gas drag, and their importance in
modifying planetesimal random velocities.


title: Models of Type I X-Ray Bursts in 4U 1820-30

abstract:
  I present ignition models for Type I X-ray bursts and superbursts from the
ultracompact binary 4U 1820-30. A pure helium secondary is usually assumed for
this system, although some evolutionary models predict a small amount of
hydrogen (around 10% by mass). I show that even this small amount of hydrogen
significantly affects the expected Type I burst properties. Using the 2-4 hour
recurrence times observed during periods of regular bursting, I determine the
accretion rate onto the star for different compositions, a new constraint on
evolutionary models. I show that models with hydrogen predict 10% variations in
burst fluence with recurrence time, which should in future allow the accreted
composition to be determined. For superbursts, I show that the expected
recurrence times are 1-2 years for pure He accretion, and 5-10 years if
hydrogen is present. These results emphasise that a combined analysis of normal
Type I X-ray bursts and superbursts is a promising way to probe the thermal
structure and composition of the neutron star's outer layers.


title: GRB 980425, SN1998bw and the EMBH model

abstract:
  The EMBH model, previously developed using GRB 991216 as a prototype, is here
applied to GRB 980425. We fit the luminosity observed in the 40-700 keV, 2-26
keV and 2-10 keV bands by the BeppoSAX satellite. In addition we present a
novel scenario in which the supernova SN1998bw is the outcome of an ``induced
gravitational collapse'' triggered by GRB 980425, in agreement with the
GRB-Supernova Time Sequence (GSTS) paradigm (Ruffini et al. 2001c). A further
outcome of this astrophysically exceptional sequence of events is the formation
of a young neutron star generated by the SN1998bw event. A coordinated
observational activity is recommended to further enlighten the underlying
scenario of this most unique astrophysical system.


title:
The XMM-LSS project: a short presentation of the survey and of the first
  results

abstract:
  We (Pierre et al. 2003) have designed a medium deep large area X-ray survey
with XMM - the XMM Large Scale Structure survey, XMM-LSS - with the scope of
extending the cosmological tests attempted using ROSAT cluster samples to two
redshift bins between 0<z<1 while maintaining the precision of earlier studies.
The optimal survey design was found to be an 8x8 deg2 area, paved with 10 ks
XMM pointing separated by 20 arcmin. This area is the target of several
complementary surveys, from the ultraviolet to the radio wavelengths, allowing,
beside cosmological studies, detailed studies of the objects included in our
area.


title:
High-Resolution Simulations of Cosmic Microwave Background non-Gaussian
  Maps in Spherical Coordinates

abstract:
  We describe a new numerical algorithm to obtain high-resolution simulated
maps of the Cosmic Microwave Background (CMB), for a broad class of
non-Gaussian models. The kind of non-Gaussianity we account for is based on the
simple idea that the primordial gravitational potential is obtained by a
non-linear but local mapping from an underlying Gaussian random field, as
resulting from a variety of inflationary models. Our technique, which is based
on a direct realization of the potential in spherical coordinates and fully
accounts for the radiation transfer function, allows to simulate non-Gaussian
CMB maps down to the Planck resolution ($\ell_{\rm max} \sim 3,000$), with
reasonable memory storage and computational time.


title:
Long-term study of water masers associated with Young Stellar Objects.
  II: Analysis

abstract:
  (Abridged) H2O masers in 14 SFRs have been monitored once every 2-3 months
for up to 13 years. We investigate the dependence of the overall spectral
morphology of the maser emission and its variability on the luminosity of the
YSO, and look for bursts and gradients in individual components. We find that
higher-luminosity sources tend to be associated with stronger and more stable
masers.Higher-luminosity YSOs can excite more emission components over a larger
range in velocity, yet the emission that dominates the spectra is at a velocity
very near that of the molecular cloud in which the objects are embedded. For
Lfir > 3E+04 Lo the maser emission becomes increasingly structured and more
extended in velocity with increasing Lfir. Below this limit the maser emission
shows the same variety of morphologies, but without a clear dependence on Lfir
and with a smaller velocity extent. Also, for sources with Lfir above this
limit, the water maser is always present above the 5sigma-level; below it, the
typical 5sigma detection rate is 75-80%. We conclude that there must be a lower
limit to Lfir, below which the associated maser is below the detection level
most of the time. These results can be understood in terms of scaled versions
of similar SFRs with different YSO luminosities, each with many potential sites
of maser amplification, which can be excited provided there is sufficient
energy to pump them, i.e. the basic pumping process is identical regardless of
the YSO luminosity. In SFRs with lower input energies, the conditions of maser
amplification are much closer to the threshold conditions, and consequently
more unstable. We find indications that the properties of the maser emission
may be determined also by the geometry of the SFR, specifically by the beaming
and collimation properties of the outflow driven by the YSO.


title:
Separation of foreground and background signals in single frequency
  measurements of the CMB Polarization

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


title: High Energy gamma-rays From FR I Jets

abstract:
  Thanks to Hubble and Chandra telescopes, some of the large scale jets in
extragalactic radio sources are now being observed at optical and X-ray
frequencies. For the FR I objects the synchrotron nature of this emission is
surely established, although a lot of uncertainties - connected for example
with the particle acceleration processes involved - remain. In this paper we
study production of high energy gamma-rays in FR I kiloparsec-scale jets by
inverse-Compton emission of the synchrotron-emitting electrons. We consider
different origin of seed photons contributing to the inverse-Compton
scattering, including nuclear jet radiation as well as ambient, stellar and
circumstellar emission of the host galaxies. We discuss how future detections
or non-detections of the evaluated gamma-ray fluxes can provide constraints on
the unknown large scale jet parameters, i.e. the magnetic field intensity and
the jet Doppler factor. For the nearby sources Centaurus A and M 87, we find
measurable fluxes of TeV photons resulting from synchrotron self-Compton
process and from comptonisation of the galactic photon fields, respectively. In
the case of Centaurus A, we also find a relatively strong emission component
due to comptonisation of the nuclear blazar photons, which could be easily
observed by GLAST at energy ~10 GeV, providing important test for the
unification of FR I sources with BL Lac objects.


title: The VIRMOS deep imaging survey: I. overview and survey strategy

abstract:
  This paper presents the CFH12K-VIRMOS survey: a deep B, V, R and I imaging
survey in four fields totalling more than 17 deg^2, conducted with the 30x40
arcmin^2 field CFH-12K camera. The survey is intended to be a multi-purpose
survey used for a variety of science goals, including surveys of very high
redshift galaxies and weak lensing studies.
  Four high galactic latitude fields, each 2x2 deg^2, have been selected along
the celestial equator: 0226-04, 1003+01, 1400+05, and 2217+00. The 16 deg^2 of
the "wide" survey are covered with exposure times of 2h, 1.5h, 1h, 1h, while
the 1.3x1 deg^2 area of the "deep" survey at the center of the 0226-04 field is
covered with exposure times of 7h, 4.5h, 3h, 3h, in B,V,R and I respectively.
  The data is pipeline processed at the Terapix facility at the Institut
d'Astrophysique de Paris to produce large mosaic images. The catalogs produced
contain the positions, shape, total and aperture magnitudes for the 2.175
million objects. The depth measured (3sigma in a 3 arc-second aperture) is
I_{AB}=24.8 in the ``Wide'' areas, and I_{AB}=25.3 in the deep area. Careful
quality control has been applied on the data as described in joint papers.
  These catalogs are used to select targets for the VIRMOS-VLT Deep Survey, a
large spectroscopic survey of the distant universe (Le F\`evre et al., 2003).
First results from the CFH12K-VIRMOS survey have been published on weak lensing
(e.g. van Waerbeke & Mellier 2003).
  Catalogs and images are available through the VIRMOS database environment
under Oracle ({\tt http://www.oamp.fr/virmos}). They will be open for general
use on July 1st, 2003.


title: Is there a Gravitational Thomas Precession ?

abstract:
  Gravitational Thomas Precession (GTP) is the name given to Thomas Precession
when the acceleration is caused by a gravitational force field. The contributio
n of the GTP to the the anomalous perihelion advance of the orbit of Mercury is
here estimated at $\dot{\tilde{\bf\omega}}_{GTP} = 21\cdot49 [ 1 + \frac{(\vec
L \cdot \vec S)}{L^{2}} ] {arcsec/century} $,where $ \vec L $ and $ \vec S $
respectively represents the orbital angular momentum and the spin angular
momentum of Mercury .This effect seems to be of some serious concern for the
General Relativity.


title:
The VIRMOS deep imaging survey II: CFH12K BVRI optical data for the
  0226-04 deep field

abstract:
  (abridged) In this paper we describe in detail the reduction, preparation and
reliability of the photometric catalogues which comprise the 1.2 deg^2
CFH12K-VIRMOS deep field. The survey reaches a limiting magnitude of BAB~26.5,
VAB~26.2, RAB~25.9 IAB~25.0 and contains 90,729 extended sources in the
magnitude range 18.0<IAB<24.0. We demonstrate our catalogues are free from
systematic biases and are complete and reliable down these limits. We estimate
that the upper limit on bin-to-bin systematic photometric errors for the I-
limited sample is ~10% in this magnitude range. We estimate that 68% of the
catalogues sources have absolute per co-ordinate astrometric uncertainties less
than ~0.38" and ~0.32" (alpha,delta). Our internal (filter-to-filter) per
co-ordinate astrometric uncertainties are 0.08" and 0.08" (alpha,delta). We
quantify the completeness of our survey in the joint space defined by object
total magnitude and peak surface brightness. Finally, we present numerous
comparisons between our catalogues and published literature data: galaxy and
star counts, galaxy and stellar colours, and the clustering of both point-like
and extended populations. In all cases our measurements are in excellent
agreement with literature data to IAB<24.0. This combination of depth and areal
coverage makes this multi-colour catalogue a solid foundation to select
galaxies for follow-up spectroscopy with VIMOS on the ESO-VLT and a unique
database to study the formation and evolution of the faint galaxy population to
z~1 and beyond.


title: Radio Detection of Cosmic Ray Air Shower by the CODALEMA Experiment

abstract:
  The possibilities of measuring Extremely High Energy Cosmic Rays (EHECR) by
radio detection of electromagnetic pulses radiated during the development of
extensive air showers in the atmosphere are investigated. We present the
demonstrative CODALEMA experiment, set up at Nancay Radio-Observatory (France).
The radio-decametric array has been adapted to measure radio transients in time
coincidence between antennas.


title: The optical and X-ray flickering of XTE J1118+480

abstract:
  We use both time-domain and Fourier techniques to study the correlated
optical and X-rays variability in the black hole X-ray nova XTE J1118+480. Its
X-ray timing properties, such as the shape of the X-ray power spectrum and
cross-correlation functions (CCFs) between X-ray energy bands, the slight
decrease of RMS variability from 30 % in the 2-5.9 keV to 19 % in the
15.5--44.4 keV band, as well as the X-ray hardness/flux anti-correlation, are
very similar to what is found in other black hole binaries in the hard state.
The optical/X-ray CCF is virtually independent of the X-ray energies. The
optical flux appears to be correlated not only with the X-ray flux but also
with the X-ray spectral variability. Both the coherence function and the lags
between optical and the X-rays are Fourier frequency dependent. The
optical/X-ray coherence function reaches its maximum (~0.3) in the 0.1-1 Hz
range and the time-lags decrease with frequency approximatively like f^-0.8.
The correlation between X-ray and optical light curves appears to have
time-scale-invariant properties. The X-ray/optical CCF maintains a similar but
rescaled shape on time-scales ranging at least from 0.1 s to few 10 s. Using
the event superposition method we show that the correlation is not triggered by
a single type of event (dip or flare) in the light curves. Instead, optical and
X-ray fluctuations of very different shapes, amplitudes and time-scales are
correlated in a similar mode where the optical light curve is seemingly related
to the time derivative of the X-rays.


title:
Constraining the population of cosmic ray protons in cooling flow
  clusters with gamma-ray and radio observations: Are radio mini-halos of
  hadronic origin?

abstract:
  We wish to constrain the cosmic-ray proton (CRp) population in galaxy
clusters. By hadronic interactions with the thermal gas of the intra-cluster
medium (ICM), the CRp produce gamma-rays for which we develop an analytic
formalism to deduce their spectral distribution. Assuming the CRp-to-thermal
energy density ratio X_CRp and the CRp spectral index to be spatially constant,
we derive an analytic relation between the gamma-ray and bolometric X-ray
fluxes, F_gamma and F_X. Based on our relation, we compile a sample of suitable
clusters which are promising candidates for future detection of gamma-rays
resulting from hadronic CRp interactions. Comparing to EGRET upper limits, we
constrain the CRp population in the cooling flow clusters Perseus and Virgo to
X_CRp < 20%. Assuming a plausible value for the CRp diffusion coefficient
kappa, we find the central CRp injection luminosity of M 87 to be limited to
10^43 erg s^-1 kappa/(10^29 cm^2 s^-1). The synchrotron emission from secondary
electrons generated in CRp hadronic interactions allows even tighter limits to
be placed on the CRp population using radio observations. We obtain excellent
agreement between the observed and theoretical radio brightness profiles for
Perseus, but not for Coma without a radially increasing CRp-to-thermal energy
density profile. Since the CRp and magnetic energy densities necessary to
reproduce the observed radio flux are very plausible, we propose synchrotron
emission from secondary electrons as an attractive explanation of the radio
mini-halos found in cooling flow clusters. This model can be tested with future
sensitive gamma-ray observations of the accompanying pi0-decays. We identify
Perseus (A 426), Virgo, Ophiuchus, and Coma (A 1656) as the most promising
candidate clusters for such observations.


title:
Probing the Cosmic Ray Population of the Giant Elliptical Galaxy M 87
  with Observed TeV Gamma-Rays

abstract:
  We examine the cosmic ray proton (CRp) population within the giant elliptical
galaxy M 87 using the TeV gamma-ray detection of the HEGRA collaboration. In
our scenario, the gamma-rays are produced by decaying pions which result from
hadronic CRp interactions with thermal gas of the interstellar medium of M 87.
By comparing the gamma-ray emission to upper limits of EGRET, we constrain the
spectral index of the CRp population to alpha(GeV,TeV) < 2.275 within our
scenario. Both the expected radial gamma-ray profile and the required amount of
CRp support this hadronic scenario. The accompanying radio mini-halo of
hadronically originating cosmic ray electrons is outshone by the synchrotron
emission of the relativistic jet of M 87 by one order of magnitude. According
to our predictions, the future GLAST mission should allow us to test this
hadronic scenario.


title: Strange stars: Can their crust reach the neutron drip density?

abstract:
  Electrostatic potential of electrons near the surface of static strange stars
at zero temperature is studied within the frame of the MIT bag model. We find
that for QCD parameters within rather wide ranges, and if the nuclear crust on
the strange star is at a density leading to neutron drip, the electrostatic
potential is insufficient to establish an outwardly directed electric field,
which is crucial for the survival of such crusts. If a minimum gap width of 200
fm is called in for a more stringent constraint, our calculations completely
rule out the possibility of such crusts' presence on strange stars. Therefore,
our results prefer against the existence of neutron-drip crust in nature.


title:
Radio structure of the most distant radio-detected quasar at the ten
  milli- arcsecond scale

abstract:
  We present a high resolution radio image of SDSS 0836+0054 identified
recently as the most distant radio-detected quasar at a redshift of z=5.82. The
observation was carried out with ten antennas of the European VLBI Network,
spread from Europe to China and South Africa, at 1.6 GHz frequency on 2002 June
8. The source is detected with a total flux density of 1.1 mJy, equal to its
flux density measured in the VLA FIRST survey. We found no indication of
multiple images produced by gravitational lensing. The radio structure of the
quasar at ~10-mas angular resolution appears somewhat resolved. It resembles
the radio structure typical for lower redshift radio-loud active galactic
nuclei. We obtained so far the best astrometric position of the source with an
accuracy better than 8 mas, limited mainly by the structural effects in the
phase-reference calibrator source.


title:
Physical Conditions and Star Formation Activity in the Intragroup Medium
  of Stephan's Quintet

abstract:
  New multi-band observations of the famous compact group of galaxies Stephan's
Quintet (SQ) are presented and analyzed. These include far infrared (FIR)
images at 60$\mu m$ and 100$\mu m$ (ISOPHOT C-100 camera), radio continuum
images at 1.4 GHz (VLA B-array) and 4.86 GHz (VLA C-array), and long-slit
optical spectrographs (Palomar $200"$ telescope). With these new data, we aim
to learn more about the X-ray/radio ridge in the middle of the intragroup
medium (IGM) and the IGM starburst SQ-A, both are likely to be caused by the
high speed collision ($\sim 900$ km s$^{-1}$) between the intruder galaxy NGC
7318b ($v = 5700$ km s$^{-1}$) and the IGM ($v = 6600$ km s$^{-1}$).


title:
Long Term X-ray Variability in GX13+1: Energy Dependent Periodic
  Modulation

abstract:
  A search is made for periodic modulation in the X-ray flux from the low mass
X-ray binary GX13+1 using Rossi X-ray Timing Explorer All Sky Monitor data
collected over a period of almost seven years. From a filtered data set, which
excludes measurements with exceptionally large error bars and so maximizes
signal to noise, modulation is found at a period of 24.065 +/- 0.018 days. The
modulation is most clearly detectable at high energies (5 - 12 keV). Spectral
changes are revealed as a modulation in hardness ratio on the 24 day period and
there is a phase shift between the modulation in the 5 - 12 keV energy band
compared to the 1.5 - 5 keV band. The high-energy spectrum of GX13+1 is unusual
in displaying both emission and absorption iron line features and it is
speculated that the peculiar spectral and timing properties may be connected.


title: The IRAS Revised Bright Galaxy Sample (RBGS)

abstract:
  IRAS flux densities, redshifts, and infrared luminosities are reported for
all sources identified in the IRAS Revised Bright Galaxy Sample (RBGS), a
complete flux-limited survey of all extragalactic objects with total 60 micron
flux density greater than 5.24 Jy, covering the entire sky surveyed by IRAS at
Galactic latitude |b| > 5 degrees. The RBGS includes 629 objects, with a median
(mean) sample redshift of 0.0082 (0.0126) and a maximum redshift of 0.0876. The
RBGS supersedes the previous two-part IRAS Bright Galaxy Samples, which were
compiled before the final ("Pass 3") calibration of the IRAS Level 1 Archive in
May 1990. The RBGS also makes use of more accurate and consistent automated
methods to measure the flux of objects with extended emission. Basic properties
of the RBGS sources are summarized, including estimated total infrared
luminosities, as well as updates to cross-identifications with sources from
optical galaxy catalogs established using the NASA/IPAC Extragalactic Database
(NED). In addition, an atlas of images from the Digitized Sky Survey with
overlays of the IRAS position uncertainty ellipse and annotated scale bars is
provided for ease in visualizing the optical morphology in context with the
angular and metric size of each object. The revised bolometric infrared
luminosity function, phi(L_ir), for infrared bright galaxies in the local
Universe remains best fit by a double power law, phi(L_ir) ~ L_ir^alpha, with
alpha = -0.6 (+/- 0.1), and alpha = -2.2 (+/- 0.1) below and above the
"characteristic" infrared luminosity L_ir ~ 10^{10.5} L_solar, respectively.
(Abridged)


title: The radial structure of galaxy groups and clusters

abstract:
  Simple self-consistent models of galaxy groups and clusters are tested
against the results of high-resolution adiabatic gasdynamical simulations. We
investigate two models based on the existence of a 'universal' dark matter
density profile and two versions of the beta-model. The mass distribution of
relaxed clusters can be fitted by phenomenological formulae proposed in the
literature. Haloes that have experienced a recent merging event are
systematically less concentrated and show steeper profiles than relaxed objects
near the centre. The hot X-ray emitting gas is found to be in approximate
hydrostatic equilibrium with the dark matter potential, and it is well
described by a polytropic equation of state. Analytic formulae for the gas
density and temperature can be derived from these premises. Though able to
reproduce the X-ray surface brightness, the beta-model is shown to provide a
poor description of our numerical clusters. We find strong evidence of a
'universal' temperature profile that decreases by a factor of 2-3 from the
centre to the virial radius, whereas baryon fraction and entropy are
monotonically increasing functions. Numerical resolution and entropy
conservation play a key role in the shapes of the profiles at small radii.


title: SACY - a Search for Associations Containing Young stars

abstract:
  The scientific goal of the SACY (Search for Associations Containing
Young-stars) was to identify possible associations of stars younger than the
Pleiades Association among optical counterparts of the ROSAT X-ray bright
sources. High-resolution spectra for possible optical counterparts later than
G0 belonging to HIPPARCOS and/or TYCHO-2 catalogs were obtained in order to
assess both the youth and the spatial motion of each target. More than 1000
ROSAT sources were observed, covering a large area in the Southern Hemisphere.
The newly identified young stars present a patchy distribution in UVW and XYZ,
revealing the existence of huge nearby young associations. Here we present the
associations identified in this survey.


title: A Method to Search for Associations of Young Stars

abstract:
  In the SACY (Search for Associations Containing Young-stars) project we try
to identify associations of stars younger than the Local Association among
HIPPARCOS and/or TYCHO-2 stars later than G0 which are counterparts of the
ROSAT X-ray bright sources. High-resolution spectra for the possible optical
counterparts were obtained in order to assess both the youth and the spatial
motion of each target. More than 1000 ROSAT sources were observed, covering a
large area in the Southern Hemisphere. Associations are characterized mainly by
the similarity in UVW velocity space of their proposed member, but other
parameters, as evolutionary age, Li abundance and distribution in space must
also be taken into account. We proposed a method to identify associations when
proper motions and radial velocities are available, but no parallaxes. Using
the method we found eleven associations in the SACY data.


title: Long Term Variability of SDSS Quasars

abstract:
  We use a sample of 3791 quasars from the Sloan Digital Sky Survey (SDSS)
Early Data Release (EDR), and compare their photometry to historic plate
material for the same set of quasars in order to study their variability
properties. The time base-line we attain this way ranges from a few months to
up to 50 years. In contrast to monitoring programs, where relatively few
quasars are photometrically measured over shorter time periods, we utilize
existing databases to extend this base-line as much as possible, at the cost of
sampling per quasar. Our method, however, can easily be extended to much larger
samples. We construct variability Structure Functions and compare these to the
literature and model functions. From our modeling we conclude that 1) quasars
are more variable toward shorter wavelengths, 2) their variability is
consistent with an exponentially decaying light-curve with a typical time-scale
of ~2 years, 3) these outbursts occur on typical time-scales of ~200 years.
With the upcoming first data release of the SDSS, a much larger quasar sample
can be used to put these conclusions on a more secure footing.


title:
Relaxation of a Collisionless System and the Transition to a New
  Equilibrium Velocity Distribution

abstract:
  In this paper, we present our conclusions from the numerical study of the
collapse of a destabilized collisionless stellar system. We use both direct
integration of the Vlasov-Poisson equations and an N-body tree code to obtain
our results, which are mutually confirmed. We find that spherical and
moderately nonspherical collapse configurations evolve to new equilibrium
configurations in which the velocity distribution approaches a Gaussian form,
at least in the central regions. The evolution to this state has long been an
open question, and in this work we are able to clarify the process responsible
and to support predictions made from statistical considerations (Lynden-Bell
1967; Nakamura 2000). The simulations of merging N-body systems show a
transition to a Gaussian velocity distribution that is increasingly suppressed
as the initial separation of centres is increased. Possible reasons for this
are discussed.


title: Cataclysmic Variables from SDSS II. The Second Year

abstract:
  The first full year of operation following the commissioning year of the
Sloan Digital Sky Survey has revealed a wide variety of newly discovered
cataclysmic variables. We show the SDSS spectra of forty-two cataclysmic
variables observed in 2002, of which thirty-five are new classifications, four
are known dwarf novae (CT Hya, RZ Leo, T Leo and BZ UMa), one is a known CV
identified from a previous quasar survey (Aqr1) and two are known ROSAT or
FIRST discovered CVs (RX J09445+0357, FIRST J102347.6+003841). The SDSS
positions, colors and spectra of all forty-two systems are presented. In
addition, the results of follow-up studies of several of these objects identify
the orbital periods, velocity curves and polarization that provide the system
geometry and accretion properties. While most of the SDSS discovered systems
are faint (>18th mag) with low accretion rates (as implied from their spectral
characteristics), there are also a few bright objects which may have escaped
previous surveys due to changes in the mass transfer rate.


title:
Evidence for an asymptotic giant branch star in the progenitor system of
  a type Ia supernova

abstract:
  A type Ia supernova (SN Ia), one of the two main classes of exploding stars,
is recognized by the absence of hydrogen and the presence of elements such as
silicon and sulphur in its spectra. These explosions are thought to produce the
majority of iron-peak elements in the universe and are known to be precise
"standard candles" used to measure distances to galaxies. While there is
general agreement that SNe Ia are exploding white dwarfs, astronomers face the
embarassing problem that the progenitor systems have never been directly
observed. Significant effort has been put into the detection of circum-stellar
material (CSM) in order to discriminate between the different types of possible
progenitors systems, yet no CSM has been found. Here we report optical
observations of SN 2002ic which reveal large amounts of CSM seen as a strong
hydrogen emission. This observation suggests that the progenitor system
contained a massive asymptotic branch giant star which lost a few solar masses
of hydrogen-rich gas prior to the type Ia explosion.


title: A search for H2 around pre-main-sequence stars

abstract:
  We present the results of a search for pure rotational molecular hydrogen
emission from two pre-main-sequence stars, AB Aur and CQ Tau. Observations were
made using MICHELLE, the mid-IR echelle spectrometer at the UK Infrared
Telescope. We found some evidence for emission in the J = 4 --> 2 line in AB
Aur, but no J = 3 --> 1 line from either star. We derive upper limits on line
flux which are significantly smaller than previous line flux estimates based on
ISO observations. This suggests that the emission detected by ISO is extended
on scales of at least 6 arcsec, and does not come from the disk as previously
thought.


title:
Comparing and combining Wilkinson Microwave Anisotropy (WMAP) probe
  results and Large Scale Structure

abstract:
  Since this is a meeting on inflation the title of this talk should probably
have been ``The cosmos as a lab for inflation''. I will illustrate how, by
combining WMAP observations of the cosmic microwave background (CMB) with
smaller scales CMB experiments and large-scale structure surveys, it is
possible to constrain inflationary models. WMAP data in combination with these
external data sets, offers a window to the very early universe and the physics
of inflation: enables us to confirm the basic tenets of the inflationary
paradigm and begin to quantitatively test inflationary models. Understanding
the complex physics and complicated systematics of the low redshift
observations is crucial to make progress in this direction.


title:
A Multiwavelength study of NLS1s galaxies from the Second Byurakan
  Survey

abstract:
  In this work we present a multiwavelength study of narrow-line Seyfert 1
galaxies (NLS1s) discovered in the Second Byurakan Survey (SBS). The sample
consists of 26 objects, which have $M_{B}\ge -23.0$, or $-19.9 > M_{B} >
-23.0$, $0.0243 < z < 0.317$ and $15.2 < B < 19.0$. For these objects, we
present accurate coordinates, magnitudes, redshifts and the identification of
optical objects with X-ray, IR and radio sources. Several galaxies are
identified as X-ray or radio sources for the first time. We also report
spectroscopic and photometric data, the spectral energy distribution,
$\alpha_{ox}$ indices and other data. Our study shows that SBS NLS1s are strong
or moderately strong soft X-ray sources with $ \log L_{x}= 42.8-45.4$. Soft
X-ray luminous sources in our sample do not tend to be luminous in the
infrared. All SBS NLS1s are radio quiet objects ($ \log L_{R}<40.0$), and 52%
of them are strong FeII emitters (FeII$\lambda4570/H\beta >1$). The traditional
linear correlation $L_x$ and $L_{op}$, which seems to hold for AGN in general,
is found for SBS NLS1s. An anticorrelation between FWHM of ${H\beta}$ and the
ratio of FeII$\lambda4570/H\beta$ is also observed. A weak correlation is found
between $\alpha_{ox}$ slope and $L_{op}$. One of our main findings is that
almost all SBS NLS1s may not have a FIR bump. Their SED suggest that they may
also possess a BBB. The absence of IR bump in most of SBS NLS1s and the
weakness of X-ray radiation in some of them, may argue against the presence of
a BLR. The surface density of SBS NLS1s is $<$ 0.015 per $deg.^2$ ($B<17.5,
z<0.16$).


title: GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy

abstract:
  GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire), a SIRTF
Legacy Science Program, will be a fully sampled, confusion-limited infrared
survey of the inner two-thirds of the Galactic disk with a pixel resolution of
\~1.2" using the Infrared Array Camera (IRAC) at 3.6, 4.5, 5.8, and 8.0
microns. The survey will cover Galactic latitudes |b| <1 degree and longitudes
|l|=10 to 65 degrees (both sides of the Galactic center). The survey area
contains the outer ends of the Galactic bar, the Galactic molecular ring, and
the inner spiral arms. The GLIMPSE team will process these data to produce a
point source catalog, a point source data archive, and a set of mosaicked
images. We summarize our observing strategy, give details of our data products,
and summarize some of the principal science questions that will be addressed
using GLIMPSE data. Up-to-date documentation, survey progress, and information
on complementary datasets are available on the GLIMPSE web site:
www.astro.wisc.edu/glimpse.


title: Inflation and Cosmological Perturbations

abstract:
  This talk, which was presented at Stephen Hawking's 60th birthday conference,
begins with a discussion of the early development of the theory of inflationary
density perturbations. Stephen played a crucial role in this work, at every
level. Much of the foundation for this work was laid by Stephen's 1966 paper on
cosmological density perturbations, and by his 1977 paper with Gary Gibbons on
quantum field theory in de Sitter space. Stephen was a major participant in the
new work, and he was also a co-organizer of the 1982 Nuffield Workshop, where
divergent ideas about inflationary density perturbations were thrashed about
until a consensus emerged. In the second part of the talk I summarize the
recent observational successes of these predictions, I present a graph of the
probability distribution for the time of last scattering for CMB photons, and I
summarize a recent theorem by Borde, Vilenkin, and me which shows that although
inflation is generically eternal to the future, an inflationary region of
spacetime must be incomplete in null and timelike past directions.


title: Splitting and focusing of neutrino collective states

abstract:
  It is shown that the collective nonlinear interactions between intense
neutrino or anti-neutrino fluxes and a dense neutrino plasma are governed by a
multi-dimensional coupled cubic Schr\"odinger equation in which the interaction
potential is positive or negative depending on the neutrino type. The cubic
Schr\"odinger equation describes the splitting and focusing of intense neutrino
beams due to the nonlinear excitations associated with the modifications of the
individual neutrino energies in a dense neutrino background.


title: The spinning-top Be star Achernar from VLTI-VINCI

abstract:
  We report here the first observations of a rapidly rotating Be star, $\alpha$
Eridani, using Earth-rotation synthesis on the Very Large Telescope (VLT)
Interferometer. Our measures correspond to a $2a/2b = 1.56\pm0.05$ apparent
oblate star, $2a$ and $2b$ being the equivalent uniform disc angular diameters
in the equatorial and polar direction. Considering the presence of a
circumstellar envelope (CSE) we argue that our measurement corresponds to a
truly distorted star since $\alpha$ Eridani exhibited negligible H$\alpha$
emission during the interferometric observations. In this framework we conclude
that the commonly adopted Roche approximation (uniform rotation and centrally
condensed mass) should not apply to $\alpha$ Eridani. This result opens new
perspectives to basic astrophysical problems, such as rotationally enhanced
mass loss and internal angular momentum distribution. In addition to its
intimate relation with magnetism and pulsation, rapid rotation thus provides a
key to the Be phenomenon: one of the outstanding non-resolved problems in
stellar physics.


title:
Curious Variables Experiment (CURVE). Superhump Period Change Pattern in
  KS UMa and Other Dwarf Novae

abstract:
  We report extensive photometry of the dwarf nova KS UMa throughout its 2003
superoutburst till quiescence. During the superoutburst the star displayed
clear superhumps with a mean period of Psh = 0.070092(23) days. In the middle
stage of superoutburst the period was increasing with a rate of $\dot P/P =
(21\pm12)\times 10^{-5}$ and later was decreasing with a rate of $\dot P/P =
-(21\pm8)\times 10^{-5}$.
  At the end of superoutburst and during first dozen days of quiescence the
star was showing late superhumps with a mean period of Plate = 0.06926(2) days.
This phenomenon was observed even 30 days after beginning of the superoutburst.
  In quiescence the star shows quasi-periodic modulations with amplitude
reaching 0.5 mag. The most common structure observed during this stage was
sinusoidal wave characterized by a period of about 0.1 days.
  Comparing KS UMa to other SU UMa stars we conclude that this group of dwarf
novae shows decreasing superhump periods at the beginning and the end of
superoutburst but increasing period in the middle phase.


title: Gauge Coupling Variation in Brane Models

abstract:
  We consider the space-time variation of gauge couplings in brane-world models
induced by the coupling to a bulk scalar field. A variation is generated by the
running of the gauge couplings with energy and a conformal anomaly while going
from the Jordan to the Einstein frame. We indicate that the one-loop
corrections cancel implying that one obtains a variation of the fine structure
constant by either directly coupling the gauge fields to the bulk scalar field
or having bulk scalar field dependent Yukawa couplings. Taking into account the
cosmological dynamics of the bulk scalar field, we constrain the strength of
the gauge coupling dependence on the bulk scalar field and relate it to
modifications of gravity at low energy.


title: FUSE Survey of the Local Interstellar Medium within 200 Parsec

abstract:
  We present FUSE observations of the interstellar gas toward 30 white dwarf
and 1 subdwarf (SdO) stars. These sightlines probe the Local Bubble (LB) and
the local interstellar medium (LISM) near the LB. Our survey detected only
diffuse H_2 molecular clouds along six sightlines. There is no evidence from
this study that H_2 exists well inside the perimeter of the LB. The kinematical
temperature for H_2 is less than the usual temperature observed in the local
interstellar clouds, implying different gas phases in the LISM. The relative
abundance ratios of Si II, P II, and Fe II give insight about the dust content.
These ratios vary, but are similar to the depletion patterns observed in warm
and halo diffuse clouds in more distant sightlines in the Galaxy. The N I/O I
and Ar I/O I ratios are significantly subsolar within the LB. Outside the LB a
larger scatter is observed from subsolar to solar. Because Ar and N are only
weakly depleted into dust grains if at all, the deficiencies of their neutral
forms are likely due to photoionization. The evidence for significant
ionization of N (and hence Ar) is strengthened by the detection and measurement
of N II, which is a dominant ion for this element toward many sightlines. These
observations imply that photoionization is the main ionization mechanism in the
LISM and do not support the existence of a highly ionized condition in the
past. In view of the variations observed in the different atomic and ionic
ratios, the photoionization conditions vary significantly in the LB and the
LISM. [Abridged.]


title:
The long time-scale X-ray variability of the radio-quiet quasar PG
  0804+761

abstract:
  We present the results from a study of the timing properties and the energy
spectrum of the radio-quiet quasar PG0804+761, based on monitoring RXTE PCA
observations that lasted for a year. This is a systematic study of the X-ray
variations on time scales of weeks/months of the most luminous radio-quiet
quasar studied so far. We detect significant variations in the 2-10 keV band of
an average amplitude of ~15%. The excess variance of the light curve is smaller
than that of Seyfert galaxies, entirely consistent with the relationship
between variability amplitude and luminosity defined from the Seyfert data
alone. The power spectrum of the source follows a power-like form of slope ~
-1. However, when we extend the power spectrum estimation at higher frequencies
using archival ASCA data, we find strong evidence for an intrinsic steepening
to a slope of ~ -2 at around ~ 1x10^(-6) Hz. This "break frequency" corresponds
to a time scale of ~ 10 days. The time-average energy spectrum is well fitted
by a power law model with Gamma ~ 2. We also find evidence for an iron line at
\~ 6.4 keV (rest frame) with EW 110 eV, similar to what is observed in Seyfert
galaxies. The flux variations are not associated with any spectral variation.
This is the only major difference that we find when we compare the variability
properties of the source with those of Seyfert galaxies. Our results support
the hypothesis that the same X-ray emission and variability mechanism operates
in both Seyfert galaxies and quasars.


title: Superheavy dark matter as UHECR source versus the SUGAR data

abstract:
  Decay or annihilation products of superheavy dark matter (SHDM) could be
responsible for the end of the Ultra-High Energy Cosmic Ray (UHECR) spectrum.
In this case, the south array of the Pierre Auger Observatory should observe in
the future a significant anisotropy of UHECR arrival directions towards the
galactic center. Here we use the already existing data of the SUGAR array to
test this possibility. If decaying SHDM is distributed according a
Navarro-Frenk-White (NFW) dark matter profile with core radius R_c=15 kpc and
is responsible only for UHECRs above 6*10^{19} eV, i.e. the AGASA excess, then
the arrival directions measured by the SUGAR array have a probability of ~10%
to be consistent with this model. By contrast, the model of annihilating SHDM
is disfavoured at least at 99% CL by the SUGAR data, if the smooth component of
the DM dominates the signal.


title: HST/WFPC2 snapshot imaging of symbiotic stars

abstract:
  The results of a HST/WFPC2 snapshot imaging survey of selected symbiotic
stars in 1999/2000 are presented. Seven sources - HD 149427 (PC 11), PU Vul, RT
Ser, He2-104 (Southern Crab), V1329 Cyg (HBV 475), V417 Cen, AS 201 - were
observed in filters F218W (ultraviolet continuum), F502N ([OIII]lambda
4959,5007) and F656N (Halpha); an eighth source, RS Oph, was observed in F437N
([OIII]lambda 4363), F502N and F656N. The presence of extended emission was
detected in He2-104, V1329 Cyg and possibly HD 149427. In He2-104 we detected
the [OIII] and Halpha counterparts to the inner lobes found in [NII] by Corradi
et al. For V1329 Cyg, comparison with previously published HST/FOC results
indicates expanding ejecta which may be associated with an ejection event in
1982 (+/-2 years) at a velocity of 260 +/- 50 km/s in the plane of the sky and
at an assumed distance of 3.4kpc. We also present previously unpublished radio
images of HD 149427, which we have obtained from the archives of the Australia
Telescope Compact Array and which reveal the presence of extended emission at a
similar orientation to that of the possible optical extension. Finally we also
include HST/WFPC2 GO observations of AG Peg and detect possible extended
emission in the F218W filter.


title: Delayed soft X-ray emission lines in the afterglow of GRB 030227

abstract:
  Strong, delayed X-ray line emission is detected in the afterglow of GRB
030227, appearing near the end of the XMM-Newton observation, nearly twenty
hours after the burst. The observed flux in the lines, not simply the
equivalent width, sharply increases from an undetectable level (<1.7e-14
erg/cm^2/s, 3 sigma) to 4.1e-14 erg/cm^2/s in the final 9.7 ks. The line
emission alone has nearly twice as many detected photons as any previous
detection of X-ray lines. The lines correspond well to hydrogen and/or
helium-like emission from Mg, Si, S, Ar and Ca at a redshift z=1.39. There is
no evidence for Fe, Co or Ni--the ultimate iron abundance must be less than a
tenth that of the lighter metals. If the supernova and GRB events are nearly
simultaneous there must be continuing, sporadic power output after the GRB of a
luminosity >~5e46 erg/s, exceeding all but the most powerful quasars.


title: Dynamical Processes in the Central Kpc and Active Galactic Nuclei

abstract:
  We discuss different aspects of nested bar dynamics and its effect on the gas
flow and fueling of Active Galactic Nuclei. Specifically we focus on the
dynamical decoupling between the primary and secondary bars and the gas flow
across the bar-bar interface. We analyze the nuclear gaseous bar formation when
gas gravity can be neglected or when it dominates. Finally, we discuss the
possible effect of flat core, triaxial, dark halos on the formation of galactic
bulges and supermassive black holes (SBHs) and argue in favor of SBH-bulge-halo
correlation.


title: Bounds on isocurvature perturbations from CMB and LSS data

abstract:
  We obtain very stringent bounds on the possible cold dark matter, baryon and
neutrino isocurvature contributions to the primordial fluctuations in the
Universe, using recent cosmic microwave background and large scale structure
data. In particular, we include the measured temperature and polarization power
spectra from WMAP and ACBAR, as well as the matter power spectrum from the 2dF
galaxy redshift survey. Neglecting the possible effects of spatial curvature,
tensor perturbations and reionization, we perform a Bayesian likelihood
analysis with nine free parameters, and find that the amplitude of the
isocurvature component cannot be larger than about 31% for the cold dark matter
mode, 91% for the baryon mode, 76% for the neutrino density mode, and 60% for
the neutrino velocity mode, at 2-sigma, for uncorrelated models. On the other
hand, for correlated adiabatic and isocurvature components, the fraction could
be slightly larger. However, the cross-correlation coefficient is strongly
constrained, and maximally correlated/anticorrelated models are disfavored.
This puts strong bounds on the curvaton model, independently of the bounds on
non-Gaussianity.


title:
Small scale systems of galaxies I. Photometric and spectroscopic
  properties of members

abstract:
  This paper is the first of a series addressed to the investigation of galaxy
formation/evolution in small scale systems of galaxies (SSSGs) which are
located in low density cosmic environments. Our algorithm for SSSG selection
includes galaxy systems of 2 or more galaxies lying within 1000 km/s and a 200
h_{100}^{-1} kpc radius volume. We present the analysis of the photometric and
spectroscopic properties of 19 member galaxies belonging to a sample of 11
SSSGs.
  In the $\mu_e - r_e$ plane, early-type members may be considered "ordinary",
not "bright" galaxies in the definition given by Capaccioli et al.(1992) with a
significant fraction of galaxies having a disk or disky isophotes. We do not
detect fine structure and signatures of recent interaction events in the
early-type galaxy population, a picture also confirmed by the spectroscopy.
  At odd, there are several spiral members with open arm configurations as
expected in interacting systems. At the same time, emission lines in the
spectra of spiral members fall in the HII regions regime defined with
diagnostic diagrams (Veilleux & Osterbrock 1987). None of the objects displays
unambiguous indication of nuclear activity, although fourspiral nuclei could be
ascribed to the class of Seyferts. The star formation rate seems enhanced over
the average expected in spiral galaxies only for poorer SSSGs in particular
pairs (<50 solar masses per year) but without being in the range of starburst
systems.


title: X-ray emission from GPS/CSS sources

abstract:
  The high spatial resolution of the Chandra X-ray Observatory allows us to
study the environment of GPS/CSS sources to within an arcsec of the strong
compact core. We present the discovery of X-ray jets in two GPS quasars,
PKS1127-145 and B2 0738+393, indicating that X-ray emission associated with the
relativistic plasma is present at large distances from the GPS nucleus. We also
discuss first results from Chandra observations of our GPS/CSS sample. We find
that 6 out of 10 sources show intrinsic absorption at a level which may be
sufficient to confine the GPS source.


title:
First results of observations of transient pulsar SAXJ2103.5+4545 with
  the INTEGRAL observatory

abstract:
  We present preliminary results of observations of X-ray pulsar SAX
J2103.5+4545 with INTEGRAL observatory in Dec 2002. Maps of this sky region in
energy bands 3-10, 15-40, 40-100 and 100-200 keV are presented. The source is
significantly detected up to energies of $\sim100$ keV. The hard X-ray flux in
the 15-100 energy band is variable, that could be connected with the orbital
phase of the binary system. We roughly reconstructed the source spectrum using
its comparison to that of Crab nebula. It is shown that the parameters of the
source spectrum in 18-150 keV energy range are compatible with that obtained
earlier by RXTE observatory


title:
Abundances in the Neutral Interstellar Medium of I Zw 18 from FUSE
  Observations

abstract:
  We report on new FUSE far-UV spectroscopy of the most metal-poor blue compact
dwarf galaxy I Zw 18. The new data represent an improvement over previous FUSE
spectra by a factor of 1.7 in the signal-to-noise. Together with a larger
spectral coverage (917-1188 angstroms), this allows us to characterize
absorption lines in the interstellar medium with unprecedented accuracy. The
kinematics averaged over the large sampled region shows no clear evidence of
gas inflows or outflows. The H I absorption is interstellar with a column
density of 2.2 (+0.6,-0.5} * 10^21 cm^(-2). A conservative 3 sigma upper limit
of 5.25 * 10^(14) cm^(-2) is derived for the column density of diffuse H_2.
  From a simultaneous fitting of metal absorption lines in the interstellar
medium, we infer the following abundances: [Fe/H] = -1.76 +/- 0.12, [O/H] =
-2.06 +/- 0.28, [Si/H] = -2.09 +/- 0.12, [Ar/H] = -2.27 +/- 0.13, and [N/H] =
-2.88 +/- 0.11. This is in general several times lower than in the H II
regions. The only exception is iron, whose abundance is the same. The abundance
pattern of the interstellar medium suggests ancient star-formation activity
with an age of at least a Gyr that enriched the H I phase. Around 470 SNe Ia
are required to produce the iron content. A more recent episode that started 10
to several 100 Myr ago is responsible for the additional enrichment of
alpha-elements and nitrogen in the H II regions.


title:
Addendum to "Coherent radio pulses from GEANT generated electromagnetic
  showers in ice"

abstract:
  We reevaluate our published calculations of electromagnetic showers generated
by GEANT 3.21 and the radio frequency pulses they produce in ice. We are
prompted by a recent report showing that GEANT 3.21-modeled showers are
sensitive to internal settings in the electron tracking subroutine. We report
the shower and pulse characteristics obtained with different settings of GEANT
3.21 and with GEANT 4. The default setting of electron tracking in GEANT 3.21
we used in previous work speeds up the shower simulation at the cost of
information near the end of the tracks. We find that settings tracking electron
and positron to lower energy yield a more accurate calculation, a more intense
shower, and proportionately stronger radio pulses at low frequencies. At high
frequencies the relation between shower tracking algorithm and pulse spectrum
is more complex. We obtain radial distributions of shower particles and phase
distributions of pulses from 100 GeV showers that are consistent with our
published results.


title:
High-Resolution Spectroscopy of Gamma-Ray Lines from the X-Class Solar
  Flare of 23 July, 2002

abstract:
  The Reuven Ramaty High Energy Solar Spectroscopy Imager (RHESSI) has obtained
the first high-resolution measurements of nuclear de-excitation lines produced
by energetic ions accelerated in a solar flare, a GOES X4.8 event occurring on
23 July, 2002 at a heliocentric angle of 73 degrees. Lines of neon, magnesium,
silicon, iron, carbon, and oxygen were resolved for the first time. They
exhibit Doppler redshifts of 0.1--0.8% and broadening of 0.1--2.1% (FWHM),
generally decreasing with mass. The measured redshifts are larger than expected
for a model of an interacting ion distribution isotropic in the downward
hemisphere in a radial magnetic field. Possible interpretations of the large
redshifts include 1) an inclination of the loop magnetic field to the solar
surface so that the ion distribution is oriented more directly away from the
observer, and 2) extreme beaming of the ions downward along a magnetic field
normal to the solar surface. Bulk downward motion of the plasma in which the
accelerated ions interact can be ruled out.


title:
The effects of Non-Gaussian initial conditions on the structure and
  substructure of Cold Dark Matter halos

abstract:
  We study the structure and substructure of halos obtained in N-body
simulations for a Lambda Cold Dark Matter (LCDM) cosmology with non-Gaussian
initial conditions (NGICs). The initial statistics are lognormal in the
gravitational potential field with positive (LNp) and negative (LNn) skewness;
the sign of the skewness is conserved by the density field, and the power
spectrum is the same for all the simulations. Our aim is not to test a given
non-Gaussian statistics, but to explore the generic effect of positive- and
negative-skew statistics on halo properties. From our low-resolution
simulations, we find that LNp (LNn) halos are systematically more (less)
concentrated than their Gaussian counterparts. This result is confirmed by our
Milky Way- and cluster-sized halos resimulated with high-resolution. In
addition, they show inner density profiles that depend on the statistics: the
innermost slopes of LNp (LNn) halos are steeper (shallower) than those obtained
from the corresponding Gaussian halos. A subhalo population embedded in LNp
halos is more susceptible to destruction than its counterpart inside Gaussian
halos. On the other hand, subhalos in LNn halos tend to survive longer than
subhalos in Gaussian halos. The spin parameter probability distribution of LNp
(LNn) halos is skewed to smaller (larger) values with respect to the Gaussian
case. Our results show how the statistics of the primordial density field can
influence some halo properties, opening this the possibility to constrain,
although indirectly, the primordial statistics at small scale.


title: String Imprints from a Pre-inflationary Era

abstract:
  We derive the equations governing the dynamics of cosmic strings in a flat
anisotropic universe of Bianchi type I and study the evolution of simple cosmic
string loop solutions. We show that the anisotropy of the background can have a
characteristic effect in the loop motion. We discuss some cosmological
consequences of these findings and, by extrapolating our results to cosmic
string networks, we comment on their ability to survive an inflationary epoch,
and hence be a possible fossil remnant (still visible today) of an anisotropic
phase in the very early universe.


title: Lithium in the Symbiotic Mira V407 Cyg

abstract:
  We report an identification of the lithium resonance doublet LiI 6708A in the
spectrum of V407 Cyg, a symbiotic Mira with a pulsation period of about 745
days. The resolution of the spectra used was R~18500 and the measured
equivalent width of the line is ~0.34A. It is suggested that the lithium
enrichment is due to hot bottom burning in the intermediate mass AGB variable,
although other possible origins cannot be totally ruled out. In contrast to
lithium-rich AGB stars in the Magellanic clouds, ZrO 5551A, 6474A absorption
bands were not found in the spectrum of V407Cyg. These are the bands used to
classify the S-type stars at low-resolution. Although we identified weak ZrO
5718A, 6412A these are not visible in the low-resolution spectra, and we
therefore classify the Mira in V407 Cyg as an M type. This, together with other
published work, suggests lithium enrichment can precede the third dredge up of
s-process enriched material in galactic AGB stars.


title: From Small-Scale Dynamo to Isotropic MHD Turbulence

abstract:
  We consider the problem of incompressible, forced, nonhelical, homogeneous,
isotropic MHD turbulence with no mean magnetic field. This problem is
essentially different from the case with externally imposed uniform mean field.
There is no scale-by-scale equipartition between magnetic and kinetic energies
as would be the case for the Alfven-wave turbulence. The isotropic MHD
turbulence is the end state of the turbulent dynamo which generates folded
fields with small-scale direction reversals. We propose that the statistics
seen in numerical simulations of isotropic MHD turbulence could be explained as
a superposition of these folded fields and Alfven-like waves that propagate
along the folds.


title:
Escape probability methods versus "exact" transfer for modelling the
  X-ray spectrum of Active Galactic Nuclei and X-ray binaries

abstract:
  In the era of XMM-Newton and Chandra missions, it is crucial to use codes
able to compute correctly the line spectrum of X-ray irradiated thick media
(Thomson thickness of the order of unity) to build models for the structure and
the emission of the central regions of AGN or X-ray binaries. In all
photoionized codes except in our code Titan, the line intensities are computed
with the "escape probability approximation". In its last version, Titan solves
the transfer of a thousand lines and of the continuum with the ``Accelerated
Lambda Iteration" method, which is one of the most efficient and most secure
for line transfer. We find that for conditions typical of the AGN or X-ray
binary emission medium, all escape approximations commonly used lead to an
overestimation of the soft X-ray lines which can reach one order of magnitude
for intense lines.


title:
Evidence for Supernova Signatures in the Spectrum of the Late-time Bump
  of the Optical Afterglow of GRB 021211

abstract:
  We present photometric and spectroscopic observations of the gamma-ray burst
GRB 021211 obtained during the late stages of its afterglow. The light curve
shows a rebrightening occurring ~25 days after the GRB. The analysis of a VLT
spectrum obtained during the bump (27 days after the GRB) reveals a suggestive
resemblance with the spectrum of the prototypical type-Ic SN 1994I, obtained
about ~10 days past maximum light. Particularly we have measured a strong,
broad absorption feature at 3770 A, which we have identified with Ca II
blueshifted by ~14400 km/s, thus indicating that a supernova (SN) component is
indeed powering the `bump' in the afterglow decay. Assuming SN 1994I as a
template, the spectroscopic and photometric data together indicate that the SN
and GRB explosions were at most separated by a few days. Our results suggest
that GRBs might be associated also to standard type-Ic supernovae.


title:
The Munich Near-Infrared Cluster Survey (MUNICS) -- II. The K-Band
  Luminosity Function of Field Galaxies to z ~ 1.2

abstract:
  (Abriged) We present a measurement of the evolution of the rest-frame K-band
luminosity function to z ~ 1.2 using a sample of more than 5000 K-selected
galaxies drawn from the MUNICS dataset. Distances and absolute K-band
magnitudes are derived using photometric redshifts from spectral energy
distribution fits to BVRIJK photometry. These are calibrated using >500
spectroscopic redshifts. We obtain redshift estimates having a rms scatter of
0.055 and no mean bias. We use Monte-Carlo simulations to investigate the
influence of the errors in distance associated with photometric redshifts on
our ability to reconstruct the shape of the luminosity function. Finally, we
construct the rest-frame K-band LF in four redshift bins spanning 0.4<z<1.2 and
compare our results to the local luminosity function. We discuss and apply two
different estimators to derive likely values for the evolution of the number
density, Phi*, and characteristic luminosity, M*, with redshift. While the
first estimator relies on the value of the luminosity function binned in
magnitude and redshift, the second estimator uses the individually measured
{M,z} pairs alone. In both cases we obtain a mild decrease in number density by
\~ 25% to z=1 accompanied by brightening of the galaxy population by 0.5 to 0.7
mag. These results are fully consistent with an analogous analysis using only
the spectroscopic MUNICS sample. The total K-band luminosity density is found
to scale as dlog(rho_L)/dz = 0.24. We discuss possible sources of systematic
errors and their influence on our parameter estimates.


title:
Measurement of the Sunyaev-Zel'dovich Increment in Massive Galaxy
  Clusters

abstract:
  We have detected the Sunyaev-Zel'dovich (SZ) increment at 850 microns in two
galaxy clusters (Cl 0016+16 and MS 1054.4-0321) using SCUBA (Sub-millimetre
Common User Bolometer Array) on the James Clerk Maxwell Telescope. Fits to the
isothermal \beta model yield a central Compton y parameter of (2.2 \pm 0.7) x
10^{-4} and a central 850 micron flux of \Delta I_{0} = 2.2 \pm 0.7 mJy/beam in
Cl 0016. This can be combined with decrement measurements to infer y = (2.38
\pm_{0.34}^{0.36}) x 10^{-4} and v_{pec} = 400 \pm_{1400}^{1900} km/s. In MS
1054 we find a peak 850 micron flux of \Delta I_{0} = 2.0 \pm 1.0 mJy/beam and
y = (2.0 \pm 1.0) x 10^{-4}. To be successful such measurements require large
chop throws and non-standard data analysis techniques. In particular, the 450
micron data are used to remove atmospheric variations in the 850 micron data.
An explicit annular model is fit to the SCUBA difference data in order to
extract the radial profile, and separately fit to the model differences to
minimize the effect of correlations induced by our scanning strategy. We have
demonstrated that with sufficient care, SCUBA can be used to measure the SZ
increment in massive, compact galaxy clusters.


title: UBVRI CCD photometry of the OB associations Bochum 1 and Bochum 6

abstract:
  We report the first deep $UBVRI$ CCD photometry of 2460 stars in the field of
two poorly studied OB associations Bochum 1 and Bochum 6. We selected 15 and 14
probable members in Bochum 1 and Bochum 6 respectively using photometric
criteria and proper motion data of Tycho 2. Our analysis indicates variable
reddening having mean value of $E(B-V)=$ 0.47$\pm$0.10 and 0.71$\pm$0.13 mag
for Bochum 1 and Bochum 6 respectively. Using the zero-age main-sequence
fitting method, we derive a distance of 2.8$\pm$0.4 and 2.5$\pm$0.4 Kpc for
Bochum 1 and Bochum 6 respectively. We obtain an age of 10$\pm$5 Myrs for both
the associations from isochrone fitting. In both associations high and low mass
stars have probably formed together. Within the observational uncertainties,
mass spectrum of the both associations appears to be similar to the Salpeter's
one.


title: H-alpha +[NII] Observations of the HII Regions in M81

abstract:
  In a first of a series of studies of the H-alpha + [NII] emission from nearby
spiral galaxies, we present measurements of H-alpha + [NII] emission from HII
regions in M81. Our method uses large-field-CCD images and long-slit spectra,
and is part of the ongoing Beijing-Arizona-Taipei-Connecticut Sky Survey. The
CCD images are taken with the NAOC 0.6/0.9m f/3 Schmidt telescope at the
Xinglong Observing Station, using a multicolor filter set. Spectra of 10 of the
brightest HII regions are obtained using the NAOC 2.16m telescope with a Tek
1024 X 1024 CCD. The continua of the spectra are calibrated by flux-calibrated
images taken from the Schmidt observations. We determine the continuum
component of our H-alpha + [NII] image via interpolation from the more
accurately-measured backgrounds (M81 starlight) obtained from the two
neighboring (in wavelength) BATC filter images. We use the calibrated fluxes of
H-alpha + [NII] emission from the spectra to normalize this interpolated,
continuum-subtracted H-alpha + [NII] image. We estimate the zero point
uncertainty of the measured H-alpha + [NII] emission flux to be $\sim$ 8%. A
catalogue of H-alpha + [NII] fluxes for 456 HII regions is provided, with those
fluxes are on a more consistent linear scale than previously available. The
logarithmically-binned H-alpha + [NII] luminosity function of HII regions is
found to have slope $\alpha$ = -0.70, consistent with previous results (which
allowed $\alpha=-0.5 \sim -0.8$). From the overall H-alpha + [NII] luminosity
of the HII regions, the star formation rate of M81 is found to be $\sim 0.68
M_{\odot} {\rm yr}^{-1}$, modulo uncertainty with extinction corrections.


title:
Cluster AgeS Experiment (CASE): RR Lyrae stars from the globular cluster
  Omega Centauri as standard candles

abstract:
  New photometry of RRab and RRc stars in Omega Cen is used to calibrate their
absolute magnitudes M_V as a function of: a) metallicity; and b) the Fourier
parameters of light curves in the V band. The zero point of both calibrations
relies on the distance modulus to the cluster derived earlier by the CASE
project based on observations of the detached eclipsing binary OGLE GC17. For
RRab variables we obtained a relation of M_V=(0.26\pm 0.08)[Fe/H]+(0.91\pm
0.13). A dereddened distance modulus to the LMC based on that formula is
$\mu_{0}=18.56\pm 0.14$ mag. The second calibration of M_V, which is based on
Fourier coefficients of decomposed light curves, results in the LMC distance of
$\mu_{0}=18.51\pm 0.07$ mag.


title: Damping of Tensor Modes in Cosmology

abstract:
  An analytic formula is given for the traceless transverse part of the
anisotropic stress tensor due to free streaming neutrinos, and used to derive
an integro-differential equation for the propagation of cosmological
gravitational waves. The solution shows that anisotropic stress reduces the
squared amplitude by 35.6 % for wavelengths that enter the horizon during the
radiation-dominated phase, independent of any cosmological parameters. This
decreases the tensor temperature and polarization correlation functions for
these wavelengths by the same amount. The effect is less for wavelengths that
enter the horizon at later times. At the longest wavelengths the decrease in
the tensor correlation functions due to neutrino free streaming ranges from
10.7% for $\Omega_Mh^2=0.1$ to 9.0% for $\Omega_Mh^2=0.15$. An Appendix gives a
general proof that tensor as well as scalar modes satisfy a conservation law
for perturbations outside the horizon, even when the anisotropic stress tensor
is not negligible.


title: Constraining slow-roll inflation with WMAP and 2dF

abstract:
  We constrain slow-roll inflationary models using the recent WMAP data
combined with data from the VSA, CBI, ACBAR and 2dF experiments. We find the
slow-roll parameters to be $0 < \epsilon_1 < 0.032$ and $\epsilon_2 + 5.0
\epsilon_1 = 0.036 \pm 0.025$. For inflation models $V \propto \phi^{\alpha}$
we find that $\alpha< 3.9, 4.3$ at the 2$\sigma$ and $3\sigma$ levels,
indicating that the $\lambda\phi^4$ model is under very strong pressure from
observations. We define a convergence criterion to judge the necessity of
introducing further power spectrum parameters such as the spectral index and
running of the spectral index. This criterion is typically violated by models
with large negative running that fit the data, indicating that the running
cannot be reliably measured with present data.


title: On the Search for Coherent Radiation from Radio Pulsars

abstract:
  We have examined data from pulsars B0950+08 and B0329+54 for evidence of
temporally coherent radiation using the modified coherence function (MCF)
technique of Jenet et al. (2001). We consider the influence of both
instrumental bandpass and interstellar propagation effects. Even after removal
of the effects due to the instrumental bandpass, we detect a signature in the
MCF of our PSR B0329+54 data which is consistent with the definition of a
coherent signal. However, we model the effects due to interstellar
scintillation for this pulsar and show that it reproduces the observed
signature. In particular, the temporal coherence time is close to the
reciprocal of the decorrelation bandwidth due to diffractive scintillation.
Furthermore, comparison of the coherence times of three pulsars reported by
Jenet et al. (2001) with their expected diffractive decorrelation bandwidths
suggests that the detection of coherence in these pulsars is also likely a
result of interstellar scintillation, and is not intrinsic to the pulsars.


title:
Deep Near Infrared Mapping of Young and Old Stars in Blue Compact Dwarf
  Galaxies

abstract:
  We analyze J, H and Ks near-infrared data for 9 Blue Compact Dwarf (BCD)
galaxies, selected from a larger sample that we have already studied in the
optical. We present contour maps, surface brightness and color profiles, as
well as color maps of the sample galaxies. The morphology of the BCDs in the
NIR has been found to be basically the same as in the optical. The inner
regions of these systems are dominated by the starburst component. At low
surface brightness levels the emission is due to the underlying host galaxy;
the latter is characterized by red, radially constant colors and isophotes well
fit by ellipses. We derive accurate optical near--infrared host galaxy colors
for eight of the sample galaxies; these colors are typical of an evolved
stellar population. Interestingly, optical near--infrared color maps reveal the
presence of a complex, large-scale absorption pattern in three of the sample
galaxies. We study the applicability of the Sersic law to describe the surface
brightness profiles of the underlying host galaxy, and find that, because of
the limited surface brightness interval over which the fit can be made, the
derived Sersic parameters are very sensitive to the selected radial interval
and to errors in the sky subtraction. Fitting an exponential model gives
generally more stable results, and can provide a useful tool to quantify the
structural properties of the host galaxy and compare them with those of other
dwarf classes as well as with those of star-forming dwarfs at higher redshifts.