title: Polarization and light curve variability: the "patchy shell" model

abstract:
  Recent advances in early detection and detailed monitoring of GRB afterglows
have revealed variability in some afterglow light curves. One of the leading
models for this behavior is the patchy shell model. This model attributes the
variability to random angular fluctuations in the relativistic jet energy.
These an-axisymmetric fluctuations should also impose variations in the degree
and angle of polarization that are correlated to the light curve variability.
In this letter we present a solution of the light curve and polarization
resulting from a given spectrum of energy fluctuations. We compare light curves
produced using this solution to the variable light curve of GRB 021004 and we
show that the main features in both the light curve and the polarization
fluctuations are very well reproduced by this model. We use our results to draw
constraints on the characteristics of the energy fluctuations that might have
been present in GRB 021004.


title: An HST Search for Lyman Continuum Emission From Galaxies at z=1.1--1.4

abstract:
  If enough of their Lyman limit continuum escapes, star-forming galaxies could
be significant contributors to the cosmic background of ionizing photons. To
investigate this possibility, we obtained the first deep imaging in the far
ultraviolet of eleven bright blue galaxies at intermediate redshift
(z=1.1--1.4). NO Lyman continuum emission was detected. Sensitive,
model-independent, upper limits of typically 2 x 10**-19 erg/sec/cm2/Ang were
obtained for the ionizing flux escaping from these normal galaxies. This
corresponds to lower limits on the observed ratio of 1500 to 700Ang flux of 150
up to 1000. Based on a wide range of stellar synthesis models, this suggests
that less than 6%, down to less than 1%, of the available ionizing flux emitted
by hot stars is escaping these galaxies. The magnitude of this spectral break
at the Lyman l imit confirms that the basic premise of `Lyman break' searches
for galaxies at high redshift can also be applied at intermediate redshifts.
This implies that the integrated contribution of galaxies to the UV cosmic
background at z around 1.2 is less than 15%, and may be less than 2%.


title: Does tiny-scale atomic structure exist in the interstellar medium ?

abstract:
  We report on preliminary results from the recent multi-epoch neutral hydrogen
absorption measurements toward three pulsars, B0823+26, B1133+16 and B2016+28,
using the Arecibo telescope. We do not find significant variations in optical
depth profiles over periods of 0.3 and 9--10 yr, or on spatial scales of 10--20
and 70--85 AU. The large number of non detections of the tiny scale atomic
structure suggests that the AU-sized structure is not ubiquitous in the
interstellar medium and could be quite a rare phenomenon.


title: Lights in the Shadows, 3D-modelling knots with MOCASSIN

abstract:
  Most of the enveloppes of Planetary Nebulae (and other objects like novae)
are far from beeing homogeneous: clumps, knots and tails are often observed. We
present here the first attempt to build a 3D-photoionization model of a knot
and the corresponding tail, ionized by diffused radiation issuing from
surrounding material.


title: Radio Interferometers with wide bandwidths

abstract:
  The Australia Telescope Compact Array and the Very Large Array are currently
being upgraded to operate with wide bandwidths; interferometers dedicated to
the measurement of cosmic microwave background anisotropies are being designed
with large instantaneous bandwidths for high sensitivity. Interferometers with
wide instantaneous bandwidths that do not operate with correlators capable of
decomposing the bands into narrow channels suffer from `bandwidth smearing'
effects in wide-field imaging. The formalism of mosaic imaging is extended here
to interferometers with finite bandwidths to examine the consequences for the
imaging of wide fields if very wide instantaneous bandwidths are used. The
formalism presented here provides an understanding of the signal processing
associated with wide-band interferometers: mosaicing may be viewed as
decomposing visibilities over wide observing bands and, thereby, avoiding
`bandwidth smearing' effects in wide-field imaging. In particular, the
formalism has implications for interferometer measurements of the angular power
spectrum of cosmic microwave background anisotropies: mosaic-mode observing
with wide-band radio interferometers decompose wide-band data and synthesize
narrow filters in multipole space.


title:
An X-ray jet discovered by Chandra in the z=4.3 radio-selected quasar GB
  1508+5714

abstract:
  We report the Chandra discovery of an X-ray jet associated with the redshift
4.3 radio-loud quasar GB 1508+5714. The jet X-ray emission peaks ~2 arcsec to
the South-West of the quasar core. We present archival HST WFPC2 data of the
quasar field which shows no optical emission at the location of the X-ray jet.
We discuss possible emission mechanisms and give constraints to the magnetic
field and energy densities for synchrotron radiation or for Compton scattering
of the Cosmic Microwave Background radiation as the jet X-ray emission process.


title: Measuring Shapes of Galaxy Images II: Morphology of 2MASS Galaxies

abstract:
  We study a sample of 112 galaxies of various Hubble types imaged in the Two
Micron All Sky Survey (2MASS) in the Near-Infra Red (NIR; 1-2 $\mu$m) $J$, $H$,
and $K_s$ bands. The sample contains (optically classified) 32 elliptical, 16
lenticulars, and 64 spirals acquired from the 2MASS Extended Source Catalogue.
We use a set of non-parametric shape measures constructed from the Minkowski
Functionals (MFs) for galaxy shape analysis.
  We use ellipticity ($\epsilon$) and orientation angle ($\Phi$) as shape
diagnostics. With these parameters as functions of area within the isophotal
contour, we note that the NIR elliptical galaxies with $\epsilon > 0.2$ show a
trend of being centrally spherical and increasingly flattened towards the edge,
a trend similar to images in optical wavelengths. The highly flattened
elliptical galaxies show strong change in ellipticity between the center and
the edge. The lenticular galaxies show morphological properties resembling
either ellipticals or disk galaxies. Our analysis shows that almost half of the
spiral galaxies appear to have bar like features while the rest are likely to
be non-barred. Our results also indicate that almost one-third of spiral
galaxies have optically hidden bars.
  The isophotal twist noted in the orientations of elliptical galaxies
decreases with the flattening of these galaxies indicating that twist and
flattening are also anti-correlated in the NIR, as found in optical
wavelengths. The orientations of NIR lenticular and spiral galaxies show a wide
range of twists.


title: Intermediate polars in low states

abstract:
  Although no intermediate polar (IP) has been observed in recent years to
descend into a state of low rate of mass transfer, there are candidate stars
that appear to be already in intermediate and low states. V709 Cas is probably
an intermediate state IP; NSV 2872 appears to be a low state IP, and will
probably resemble the long orbital period IP V1072 Tau if it returns to a high
state. The enigmatic V407 Vul, which has had many interpretations as an
ultra-short period binary, has many resemblances to the pre-cataclysmic
variable V471 Tau, and may therefore be an IP precursor of quite long orbital
period, and not yet a fully fledged cataclysmic variable.


title: Accretion in Cataclysmic Variable stars

abstract:
  We consider accretion onto the white dwarfs in cataclysmic variables in
relation to nova eruptions, dwarf nova outbursts, hibernation and non-radial
oscillations.


title: Anisotropic Heat Transfer inside Rotating Neutron Stars

abstract:
  We have developed the anisotropic heat transport equation for rotating
neutron stars. With a simple model of neutron star, we also model the
propagation of heat pulses result from transient energy releases inside the
star. Even in slow rotation limit, the results with rotational effects involved
could differ significantly from those obtained with a spherically symmetric
metric in the time scale of the thermal afterglow.


title:
Ground-based characterisation of the asteroseismic targets for the COROT
  space mission

abstract:
  We illustrate the approach to the use of asteroseismology to sound stellar
interiors. We also present the spectroscopic and photometric observations
carried out to give the complete characterisation of the potential targets of
the space mission COROT. The Italian contribution plays an important role in
the preparation of the observational basis of this space mission. The use of
the TNG/SARG high-resolution spectra is described.


title: Effelsberg HI Survey of Compact High-Velocity Clouds

abstract:
  We studied 11 compact high-velocity clouds (CHVCs) in the 21-cm line emission
of neutral hydrogen with the 100-m telescope in Effelsberg. We find that most
of our CHVCs are not spherically-symmetric as we would expect in case of a
non-interacting, intergalactic population. Instead, many CHVCs reveal a complex
morphology suggesting that they are disturbed by ram-pressure interaction with
an ambient medium. Thus, CHVCs are presumably located in the neighborhood of
the Milky Way instead of being spread across the entire Local Group.


title:
BeppoSAX observations of Seyfert 1s in the Piccinotti sample I: poorly
  studied sources

abstract:
  In this work we present the first of two papers devoted to the study of the
X-ray spectral characteristics of Seyfert 1 galaxies in the Piccinotti sample.
In particular we analyse here the BeppoSAX broad band (0.1-100 keV) data of 4
objects which, despite their X-ray brightness, have been historically poorly
studied due to their late identification with an AGN; these are H0111-149
(MKN1152), H0235-525 (ESO198-G24), H0557-385 (IRAS F05563-3820) and H1846-786
(IRAS F18389-7834). We have assumed for all the sources a baseline model which
includes a power law with an exponential cut-off plus a reflection component
and an iron K_alpha line; we have also searched for the presence of intrinsic
absorption and/or a soft excess component. Our analysis indicates the presence
of complex absorption in two objects (H0557-385 and H0111-149) best described
by a combination of two uniform absorbers, one cold and one warm. Only in one
source, H0557-385, a soft excess component has been measured. The primary
continuum is best described by a canonical power law (Gamma=1.7-2) with a high
energy cut-off in the range 40-130 keV. A cold reflection component is likely
present in all sources with values ranging from less than 0.6 to higher than 2.
In 3 out of 4 objects we find a cold iron line having equivalent width typical
of Seyfert 1s (100-200 eV).


title: Comparison between optical and X-ray cluster detection methods

abstract:
  In this work we present combined optical and X-ray cluster detection methods
in an area near the North Galactic Pole area, previously covered by the SDSS
and 2dF optical surveys. The same area has been covered by shallow ($\sim 1.8$
deg$^{2}$) XMM-{\em Newton} observations. The optical cluster detection
procedure is based on merging two independent selection methods - a
smoothing+percolation technique, and a Matched Filter Algorithm. The X-ray
cluster detection is based on a wavelet-based algorithm, incorporated in the
SAS v.5.2 package. The final optical sample counts 9 candidate clusters with
richness of more than 20 galaxies, corresponding roughly to APM richness class.
Three, of our optically detected clusters are also detected in our X-ray
survey.


title: X-ray Observations of the Compact Source in CTA 1

abstract:
  The point source RX J0007.0+7302, at the center of supernova remnant CTA 1,
was studied using the X-Ray Multi-mirror Mission. The X-ray spectrum of the
source is consistent with a neutron star interpretation, and is well described
by a power law with the addition of a soft thermal component that may
correspond to emission from hot polar cap regions or to cooling emission from a
light element atmosphere over the entire star. There is evidence of extended
emission on small spatial scales which may correspond to structure in the
underlying synchrotron nebula. No pulsations are observed. Extrapolation of the
nonthermal spectrum of RX J0007.0+7302 to gamma-ray energies yields a flux
consistent with that of EGRET source 3EG J0010+7309, supporting the proposition
that there is a gamma-ray emitting pulsar at the center of CTA 1. Observations
of the outer regions of CTA 1 with the Advanced Satellite for Cosmology and
Astrophysics confirm earlier detections of thermal emission from the remnant
and show that the synchrotron nebula extends to the outermost reaches of the
SNR.


title:
Photo-Chemical Evolution of Elliptical Galaxies I. The high-redshift
  formation scenario

abstract:
  In this paper we compute new multi-zone photo-chemical evolution models for
elliptical galaxies, taking into account detailed nucleosynthetic yields,
feedback from supernovae and an initial infall episode. By comparing model
predictions with observations, we derive a picture of galaxy formation in which
the higher is the mass of the galaxy, the shorter are the infall and the star
formation timescales. Therefore, in this scenario, the most massive objects are
older than the less massive ones, in the sense that larger galaxies stop
forming stars at earlier times. Each galaxy is created outside-in, i.e. the
outermost regions accrete gas, form stars and develop a galactic wind very
quickly, compared to the central core in which the star formation can last up
to ~1.3 Gyr. In particular, we suggest that both the duration of the star
formation and the infall timescale decrease with galactic radius. (abridged) By
means of our model, we are able to match the observed mass-metallicity and
color-magnitude relations for the center of the galaxies as well as to
reproduce the overabundance of Mg relative to Fe, observed in the nuclei of
bright ellipticals, and its increase with galactic mass. Furthermore, we find
that the observed Ca underabundance relative to Mg can be real, due to the
non-neglibile contribution of type Ia SN to the production of this element. We
predict metallicity and color gradients inside the galaxies which are in good
agreement with the mean value of the observed ones. (abridged)


title: Phase Correlations in Cosmic Microwave Background Temperature Maps

abstract:
  We study the statistical properties of spherical harmonic modes of
temperature maps of the cosmic microwave background. Unlike other studies,
which focus mainly on properties of the amplitudes of these modes, we look
instead at their phases. In particular, we present a simple measure of phase
correlation that can be diagnostic of departures from the standard assumption
that primordial density fluctuations constitute a statistically homogeneous and
isotropic Gaussian random field, which should possess phases that are uniformly
random on the unit circle. The method we discuss checks for the uniformity of
the distribution of phase angles using a non-parametric descriptor based on the
use order statistics, which is known as Kuiper's statistic. The particular
advantage of the method we present is that, when coupled to the judicious use
of Monte Carlo simulations, it can deliver very interesting results from small
data samples. In particular, it is useful for studying the properties of
spherical harmonics at low l for which there are only small number of
independent values of m and which therefore furnish only a small number of
phases for analysis. We apply the method to the COBE-DMR and WMAP sky maps, and
find departures from uniformity in both. In the case of WMAP, our results
probably reflect Galactic contamination or the known variation of
signal-to-noise across the sky rather than primordial non-Gaussianity.


title:
Dodecahedral space topology as an explanation for weak wide-angle
  temperature correlations in the cosmic microwave background

abstract:
  Cosmology's standard model posits an infinite flat universe forever expanding
under the pressure of dark energy. First-year data from the Wilkinson Microwave
Anisotropy Probe (WMAP) confirm this model to spectacular precision on all but
the largest scales (Bennett {\it et al.}, 2003 ; Spergel {\it et al.}, 2003).
Temperature correlations across the microwave sky match expectations on scales
narrower than $60^{\circ}$, yet vanish on scales wider than $60^{\circ}$.
Researchers are now seeking an explanation of the missing wide-angle
correlations (Contaldi {\it et al.}, 2003 ; Cline {\it et al.}, 2003). One
natural approach questions the underlying geometry of space, namely its
curvature (Efstathiou, 2003) and its topology (Tegmark {\it et al.}, 2003). In
an infinite flat space, waves from the big bang would fill the universe on all
length scales. The observed lack of temperature correlations on scales beyond
$60^{\circ}$ means the broadest waves are missing, perhaps because space itself
is not big enough to support them.
  Here we present a simple geometrical model of a finite, positively curved
space -- the Poincar\'e dodecahedral space -- which accounts for WMAP's
observations with no fine-tuning required. Circle searching (Cornish, Spergel
and Starkman, 1998) may confirm the model's topological predictions, while
upcoming Planck Surveyor data may confirm its predicted density of $\Omega_0
\simeq 1.013 > 1$. If confirmed, the model will answer the ancient question of
whether space is finite or infinite, while retaining the standard
Friedmann-Lema\^\i{}tre foundation for local physics.


title:
An L'-band survey for circumstellar disks around low-mass stars in the
  young sigma Orionis cluster

abstract:
  We present new K- and L'-band imaging of a representative sample of members
of the young 3-5 Myr old sigma Orionis cluster. We identified objects with
(K-L') excess by analysing colour-colour diagrams and comparing the
observations with empirical main-sequence colours. The derived disk frequency
depends on the method used: (54 +/- 15)% if measured directly from the JHKL'
colour-colour diagram; or (46 +/-14)% if excesses are computed with respect to
predicted photospheric colours (according to the objects spectral types,
2-sigma excess detections). We compare the (K-L') excess with other indicators
and show that this is a robust and reliable disk indicator. We also compare the
derived disk frequency with similarly aged clusters and discuss possible
implications for disk lifetimes. The computed age of the sigma Ori cluster is
very important: a cluster age of 3 Myr would support the overall disk lifetime
of 6 Myr proposed in the literature, while an age > 4 Myr would point to a
slower disk destruction rate.


title:
A more detailed look at the Opacities for Enriched Carbon and Oxygen
  Mixtures

abstract:
  We have included opacity tables in our stellar evolution code that enable us
to accurately model the structure of stars composed of mixtures with carbon and
oxygen independently enhanced relative to solar. We present tests to
demonstrate the effects of the new tables. Two of these are practical examples,
the effect on the evolution of a thermally pulsing asymptotic giant branch star
and a Wolf-Rayet Star. The changes are small but perceptible.


title: Emission lines and optical continuum in low-luminosity radio galaxies

abstract:
  We present spectroscopic observations of a complete sub-sample of 13
low-luminosity radio galaxies selected from the 2Jy sample. The underlying
continuum in these sources is carefully modelled in order to make a much-needed
comparison between the emission line and continuum properties of FRIs with
those of other classes of radio sources. We find that 5 galaxies in the sample
show a measurable UV excess: 2 of the these sources are BL Lacs and in the
remaining 3 galaxies we argue that the most likely contributor to the UV excess
is a young stellar component. Excluding the BL Lacs, we therefore find that
\~30% of the sample show evidence for young stars, which is similar to the
results obtained for higher luminosity samples. We compare our results with
far-infrared measurements in order to investigate the far-infrared-starburst
link. The nature of the optical-radio correlations is investigated in light of
this new available data and, in contrast to previous studies, we find that the
FRI sources follow the correlations with a similar slope to that found for the
FRIIs. Finally, we compare the luminosity of the emission lines in the FRI and
BL Lac sources and find a significant difference in the [OIII] line
luminosities of the two groups. Our results are discussed in the context of the
unified schemes.


title: Exploring the complex X-ray spectrum of NGC 4051

abstract:
  Archival XMM-Newton data on the nearby Seyfert galaxy NGC 4051, taken in
relatively high and low flux states, offer a unique opportunity to explore the
complexity of its X-ray spectrum. We find the hard X-ray band to be
significantly affected by reflection from cold matter, which can also explain a
non-varying, narrow Fe K fluorescent line. We interpret major differences
between the high and low flux hard X-ray spectra in terms of the varying
ionisation (opacity) of a substantial column of outflowing gas. An emission
line spectrum in the low flux state indicates an extended region of
photoionised gas. A high velocity, highly ionised outflow seen in the high
state spectrum can replenish the gas in the extended emission region over ~10^3
years, while having sufficient kinetic energy to contribute significantly to
the hard X-ray continuum.


title:
The magnetic field of M31 from multi-wavelength radio polarization
  observations

abstract:
  The configuration of the regular magnetic field in M31 is deduced from radio
polarization observations at the wavelengths 6, 11 and 20 cm. By fitting the
observed azimuthal distribution of polarization angles, we find that the
regular magnetic field, averaged over scales 1--3 kpc, is almost perfectly
axisymmetric in the radial range 8 to 14 kpc, and follows a spiral pattern with
pitch angles of $p\simeq -19\degr$ to $p\simeq -8\degr$. In the ring between 6
and 8 kpc a perturbation of the dominant axisymmetric mode may be present,
having the azimuthal wave number m=2. A systematic analysis of the observed
depolarization allows us to identify the main mechanism for wavelength
dependent depolarization -- Faraday rotation measure gradients arising in a
magneto-ionic screen above the synchrotron disk. Modelling of the
depolarization leads to constraints on the relative scale heights of the
thermal and synchrotron emitting layers in M31; the thermal layer is found to
be up to three times thicker than the synchrotron disk. The regular magnetic
field must be coherent over a vertical scale at least similar to the scale
height of the thermal layer, estimated to be $h\therm\simeq 1$ kpc. Faraday
effects offer a powerful method to detect thick magneto-ionic disks or halos
around spiral galaxies.


title:
Thermal states of coldest and hottest neutron stars in soft X-ray
  transients

abstract:
  We calculate the thermal structure and quiescent thermal luminosity of
accreting neutron stars (warmed by deep crustal heating in accreted matter) in
soft X-ray transients (SXTs). We consider neutron stars with nucleon and
hyperon cores and with accreted envelopes. It is assumed that an envelope has
an outer helium layer (of variable depth) and deeper layers of heavier
elements, either with iron or with much heavier nuclei (of atomic weight A >
100) on the top (Haensel & Zdunik 1990, 2003, astro-ph/0305220). The relation
between the internal and surface stellar temperatures is obtained and fitted.
The quiescent luminosity of the hottest (low-mass) and coldest (high-mass)
neutron stars is calculated, together with the ranges of its possible
variations due to variable thickness of the helium layer. The results are
compared with observations of SXTs, particularly, containing the coldest (SAX
J1808.4-3658) and the hottest (Aql X-1) neutron stars. The observations of SAX
J1808.4-3658 in a quiescent state on March 24, 2001 (Campana et al. 2002,
astro-ph/0206376) can be explained only if this SXT contains a massive neutron
star with a nucleon/hyperon core; a hyperon core with a not too low fraction of
electrons is preferable. Future observations may discriminate between the
various models of hyperon/nucleon dense matter. The thermal emission of SAX
J1808.4-3658 is also sensitive to the models of plasma ionization in the
outermost surface layers and can serve for testing such models.


title: Asymfast, a method for convolving maps with asymmetric main beams

abstract:
  We describe a fast and accurate method to perform the convolution of a sky
map with a general asymmetric main beam along any given scanning strategy. The
method is based on the decomposition of the beam as a sum of circular
functions, here Gaussians. It can be easily implemented and is much faster than
pixel-by-pixel convolution. In addition, Asymfast can be used to estimate the
effective circularized beam transfer functions of CMB instruments with
non-symmetric main beam. This is shown using realistic simulations and by
comparison to analytical approximations which are available for Gaussian
elliptical beams. Finally, the application of this technique to Archeops data
is also described. Although developped within the framework of Cosmic Microwave
Background observations, our method can be applied to other areas of
astrophysics.


title:
The ELODIE survey for northern extra-solar planets III. Three planetary
  candidates detected with ELODIE

abstract:
  We present our ELODIE radial-velocity measurements of HD 74156 and 14 Her (HD
145675). These stars exhibit low-amplitude radial-velocity variations induced
by the presence of low-mass companions. The radial-velocity data of HD 74156
reveal the presence of two planetary companions: a 1.86 M_Jup planet on a
51.64--d orbit and a 6.2 M_Jup planet on a long-period (5.5 yr) orbit. Both
orbits are fairly eccentric (e=0.64 and 0.58). The 4.7M_Jup companion to HD
145675 has a long period (4.9 yr) and a moderately eccentric orbit (e=0.34). We
detect an additional linear radial-velocity trend superimposed to the periodic
signal for this star. We also compute updated orbital solutions for HD 209458
and 51 Peg (HD 217014). Finally, we present our ELODIE radial-velocity data and
orbital solutions for 5 stars known to host planetary companions: Ups And (HD
9826), 55 Cnc (HD 75732), 47 UMa (HD 95128), 70Vir (HD 117176) and HD 187123.
We confirm the previously published orbital solutions for Ups And, 70 Vir and
HD 187123. Our data are not sufficient for fully confirming the orbital
solutions for 55 Cnc and 47UMa.


title: The peculiar circumstellar environment of NGC2024-IRS2

abstract:
  We re-examine the nature of NGC2024-IRS2 in light of the recent discovery of
the late O-type star, IRS2b, located 5 arcsec from IRS2. Using L-band
spectroscopy, we set a lower limit of Av = 27.0 mag on the visual extinction
towards IRS2. Arguments based on the nature of the circumstellar material,
favor an Av of 31.5 mag. IRS2 is associated with the UCHII region
G206.543-16.347 and the infrared source IRAS 05393-0156. We show that much of
the mid-infrared emission towards IRS2, as well as the far infrared emission
peaking at ~ 100 micron, do not originate in the direct surroundings of IRS2,
but instead from an extended molecular cloud. Using new K-, L- and L'-band
spectroscopy and a comprehensive set of infrared and radio continuum
measurements from the literature, we apply diagnostics based on the radio
slope, the strength of the infrared hydrogen recombination lines, and the
presence of CO band-heads to constrain the nature and spatial distribution of
the circumstellar material of IRS2. Using simple gaseous and/or dust models of
prescribed geometry, we find strong indications that the infrared flux
originating in the circumstellar material of IRS2 is dominated by emission from
a dense gaseous disk with a radius of about 0.6 AU. At radio wavelengths the
flux density distribution is best described by a stellar wind recombining at a
radius of about 100 AU. Although NGC2024/IRS2 shares many similarities with
BN-like objects, we do not find evidence for the presence of a dust shell
surrounding this object. Therefore, IRS2 is likely more evolved.


title: A Taxonomy of Extended Radio Sources in Clusters of Galaxies

abstract:
  At the request of the conference attendees, we have compiled a classification
of extended radio sources in clusters. These range from scales of tens of
parsecs to over a megaparsec in scale, and include both sources associated with
AGN and sources thought to derive from the electron population in the ionized
ICM. We pay special attention to distinguishing between the types of AGN in the
cores of cooling flow clusters and between the multiple classes of objects
referred to over the years as ``radio relics.'' We suggest new names based on
physical arguments for some of these classes of objects where their commonly
used names are inappropriate or confusing.


title:
Clustering and light profiles of galaxies in the environment of 20 Ultra
  Steep Spectrum Radio sources

abstract:
  We have analyzed galaxy properties in the neighborhood of 20 Ultra-Steep
Spectrum Radio sources (USS) taken from the WISH catalog of De Breuck et al.
(2002). Galaxies in these USS fields were identified in deep observations that
were carried out in the K'-band using the OSIRIS imager at the CTIO 4m
telescope. We find a statistically significant signal of clustering around our
sample of USS. The angular extension of the detected USS-galaxy clustering is
theta_c~20" corresponding to a spatial scale ~120 h^{-1}kpc, assuming the
sources are at z~1 in a Omega_m=0.3, Omega_{\Lambda}=0.7 model universe. These
results are in agreement with those obtained by Best (2000) for radio
galaxy-galaxy correlation, and Best et al. (2003) for radio-loud AGN-galaxy
correlation. We have also analyzed the light distribution of the galaxies by
fitting Sersic's law profiles. Our results show no significant dependence of
the galaxy shape parameters on the projected distance to the USS.


title: Chandra Observation of the Core of Abell 576

abstract:
  We present data from a Chandra observation of the nearby cluster of galaxies
Abell 576. The core of the cluster shows a significant departure from dynamical
equilibrium. We show that this core gas is most likely the remnant of a merging
subcluster, which has been stripped of much of its gas, depositing a stream of
gas behind it in the main cluster. The unstripped remnant of the subcluster is
characterized by a different temperature, density and metalicity than that of
the surrounding main cluster, suggesting its distinct origin. Continual
dissipation of the kinetic energy of this minor merger may be sufficient to
counteract most cooling in the main cluster over the lifetime of the merger
event.


title: Far Infrared mapping of NGC 891

abstract:
  We present deep maps of dust emission from the edge-on spiral galaxy NGC 891,
obtained with the ISOPHOT instrument on board the Infrared Space Observatory in
broad band filters with reference wavelengths centered on 170 and 200 micron.
Using new processing methods to remove the effects of detector transients from
the data, we detect cold dust at high dynamic range. The observed surface
brightness distribution and colour profile of the far-infrared (FIR) emission
are found to be in good agreement with predictions for their counterparts
derived from the model of Popescu et al. (2000a). Thus, NGC 891 is the first
galaxy for which an intrinsic distribution of dust and stars could be found
which simultaneously accounts for both the optical/near-IR and FIR
morphologies.


title: The cosmological evolution of quasar black-hole masses

abstract:
  Virial black-hole mass estimates are presented for 12698 quasars in the
redshift interval 0.1<z<2.1, based on modelling of spectra from the Sloan
Digital Sky Survey (SDSS) first data release. The black-hole masses of the SDSS
quasars are found to lie between $\simeq10^{7}\Msun$ and an upper limit of
$\simeq 3\times 10^{9}\Msun$, entirely consistent with the largest black-hole
masses found to date in the local Universe. The estimated Eddington ratios of
the broad-line quasars (FWHM\geq 2000 kms^{-1}) show a clear upper boundary at
$L_{bol}/L_{Edd}\simeq 1$, suggesting that the Eddington luminosity is still a
relevant physical limit to the accretion rate of luminous broad-line quasars at
$z\leq 2$. By combining the black-hole mass distribution of the SDSS quasars
with the 2dF quasar luminosity function, the number density of active black
holes at $z\simeq 2$ is estimated as a function of mass. In addition, we
independently estimate the local black-hole mass function for early-types using
the $M_{bh}-\sigma$ and $M_{bh}-L_{bulge}$ correlations. Based on the SDSS
velocity dispersion function and the 2MASS $K-$band luminosity function, both
estimates are found to be consistent at the high-mass end ($M_{bh}\geq
10^{8}\Msun$). By comparing the estimated number density of active black holes
at $z\simeq 2$ with the local mass density of dormant black holes, we set lower
limits on the quasar lifetimes and find that the majority of black holes with
mass $\geq 10^{8.5}\Msun$ are in place by $\simeq 2$.


title:
Chemical enrichment of the intra-cluster and intergalactic medium in a
  hierarchical galaxy formation model

abstract:
  (Abridged) We use a combination of high resolution N-body simulations and
semi-analytic techniques to follow the formation, the evolution and the
chemical enrichment of cluster galaxies in a Lambda-CDM Universe. We model the
transport of metals between the stars, the cold gas in galaxies, the hot gas in
dark matter haloes, and the intergalactic gas outside virialized haloes. We
have compared three different feedback schemes. The `retention' model assumes
that material reheated by supernova explosions is able to leave the galaxy, but
not the dark matter halo. The `ejection' model assumes that this material
leaves the halo and is then re-incorporated when structure collapses on larger
scales. The `wind' model uses prescriptions that are motivated by observations
of local starburst galaxies. We require that our models reproduce the cluster
LF from the 2dF survey, the relations between stellar mass, gas mass and
metallicity inferred from new SDSS data, and the observed amount of metals in
the ICM. With suitable adjustment of the free parameters in the model, a
reasonable fit to the observational results at redshift zero can be obtained
for all three feedback schemes. All three predict that the chemical enrichment
of the ICM occurs at high redshift with 60-80 per cent of the metals currently
in the ICM ejected at redshifts larger than 1. Massive galaxies are important
contributors to the chemical pollution. The observed decline in baryon fraction
from rich clusters to galaxy groups is reproduced only in an `extreme' ejection
scheme, where material ejected from dark matter haloes is re-incorporated on a
timescale comparable to the age of the Universe. We explore how the metal
abundance in the intergalactic medium as a function of redshift can constraint
how and when galaxies ejected their metals.


title: Influence of the Interstellar Medium on the Shaping of Planetary Nebulae

abstract:
  The interaction of the ISM with the evolution of PNe is studied for cases
where there is a large relative velocity between ISM and central star, for
example for high-proper motion PNe. In such cases the ISM wind already
interacts strongly with the AGB wind, and extensive PN asymmetries result.


title:
Understanding the Chandra detected X-ray emission of the knots and hot
  spots of powerful extragalactic jets

abstract:
  I present here a short personal view of our understanding of the Chandra
detected knots and hot spots of powerful Fanaroff Rilley (FR) II radio galaxies
and quasars in the context of leptonic models. Observations of the knots and
hot spots strongly suggest that the jets in these powerful sources retain their
relativistic velocities at large scales, all the way to the hot spots. The
emission mechanism suggested for the knots of quasars and FR II radio galaxies
is external Compton (EC) off the cosmic microwave backgounrd (CMB) from a
relativistic flow, while for the hotspots Upstream Compton (UC) scattering from
a decelerating relativistic flow.


title:
XMM-Newton light curves of the low-mass X-ray binary EXO 0748--676:
  dips, eclipses, and bursts

abstract:
  We present an analysis of XMM-Newton light curves of the dipping, bursting,
and eclipsing low-mass X-ray binary EXO 0748-676, focusing on the variability
on time scales of seconds to hours. The observed variability can be roughly
divided in three types: dips, eclipses and bursts. We find that the appearance
of the latter two, depends strongly on the strength of the first. We show that
the absorption dips change from spectrally hard to spectrally soft as they
become deeper, which supports suggestions that the source is composed of a
spectrally hard compact source and a spectrally soft extended source. The fast
variability in the soft light curve indicates that the large structures causing
the dips are made up of smaller absorption cores. We present the first clear
detection with XMM-Newton of eclipses below 2 keV in this source, and show that
dipping activity is apparently unrelated to the source luminosity. We also test
several proposed models for the spectral evolution during dips and confirm the
presence of a scatter/reflection component in the eclipse spectrum.


title: Complex Absorption Hides a Type II QSO in IRAS 13197-1627

abstract:
  We report on the analysis of a BeppoSAX observation of IRAS 13197-1627. The
complexity of the broad band (0.3-100 keV) spectrum of the source prevents us
from selecting from two possible best-fit models, i.e. one based on a partial
covering and the other on a reflection dominated scenario. Whatever the best
fit model, the data imply that: 1) the primary spectrum is heavily obscured by
at least two absorbers with column densities of the order of 5x10^23 cm-2 and
>2x10^24 cm-2; 2) the intrinsic 2-10 keV luminosity of the source is at least
\~2x10^44 erg/s thus making IRAS 13197-1627 a type-II QSO (more precisely a
type 1.8 QSO) rather than a Seyfert 1.8 galaxy as previously classified.
Furthermore, there is marginal evidence of an absorption line at E $\sim$7.5
keV suggesting a possible outflow with v~0.1c similar to recent findings on
other QSOs and Seyferts.


title:
Detection of non-Gaussianity in the WMAP 1-year data using spherical
  wavelets

abstract:
  A non-Gaussian detection in the WMAP 1-year data is reported. The detection
has been found in the combined Q-V-W map proposed by the WMAP team (Komatsu et
al. 2003) after applying a wavelet technique based on the Spherical Mexican Hat
Wavelet (SMHW). The skewness and the kurtosis of the SMHW coefficients are
calculated at different scales. A non-Gaussian signal is detected at scales of
the SMHW around 4 deg (size in the sky of around 10 deg). The right tail
probability of the detection is approx. 0.4%. In addition, a study of
Gaussianity is performed in each hemisphere. The northern hemisphere is
compatible with Gaussianity, whereas the southern one deviates from Gaussianity
with a right tail probability of approx. 0.1%. Systematics, foregrounds and
uncertainties in the estimation of the cosmological parameters are carefully
studied in order to identify the possible source of non-Gaussianity. The
detected deviation from Gaussianity is not found to be caused by systematic
effects: 1) each one of the Q, V and W receivers shows the same non-Gaussianity
pattern, and 2) several combinations of the different receivers at each
frequency band do not show this non-Gaussian pattern. Similarly, galactic
foregrounds show a negligible contribution to the non-Gaussian detection:
non-Gaussianity is detected in all the WMAP maps and no frequency dependence is
observed. Moreover, the expected foreground contribution to the combined WMAP
map was added to CMB Gaussian simulations showing a behaviour compatible with
the Gaussian model. Influence of uncertainties in the CMB power spectrum
estimation are also quantified. Hence, possible intrinsic temperature
fluctuations (like secondary anisotropies and primordial features) can not be
rejected as the source of this non-Gaussian detection.


title: A New SU UMa-Type Dwarf Nova, QW Serpentis (= TmzV46)

abstract:
  We report on the results of the QW Ser campaign which has been continued from
2000 to 2003 by the VSNET collaboration team. Four long outbursts and many
short ones were caught during this period. Our intensive photometric
observations revealed superhumps with a period of 0.07700(4) d during all four
superoutbursts, proving the SU UMa nature of this star. The recurrence cycles
of the normal outbursts and the superoutbursts were measured to be $\sim$50
days and 240(30) days, respectively. The change rate of the superhump period
was -5.8x10^{-5}. The distance and the X-ray luminosity in the range of 0.5-2.4
keV are estimated to be 380(60) pc and log L_x = 31.0 \pm 0.1 erg s^{-1}. These
properties have typical values for an SU UMa-type dwarf nova with this
superhump period.


title:
O stars effective temperature and HII regions ionization parameter
  gradients in the Galaxy

abstract:
  Extensive photoionization model grids are computed for single star HII
regions using stellar atmosphere models from the WM-basic code. Mid-IR emission
line intensities are predicted and diagnostic diagrams of [NeIII]/[NeII] and
[SIV]/[SIII] excitation ratio are build, taking into account the metallicities
of both the star and the HII region. The diagrams are used in conjunction with
galactic HII region observations obtained with the ISO Observatory to determine
the effective temperature Teff of the exciting O stars and the mean ionization
parameter U. Teff and U are found to increase and decrease, respectively, with
the metallicity of the HII region represented by the [Ne/Ne_sol] ratio. No
evidence is found for gradients of Teff or U with galactocentric distance Rgal.
The observed excitation sequence with Rgal is mainly due to the effect of the
metallicity gradient on the spectral ionizing shape, upon which the effect of
an increase in Teff with Z is superimposed. We show that not taking properly
into account the effect of metallicity on the ionizing shape of the stellar
atmosphere would lead to an apparent decrease of Teff with Z and an increase of
Teff with Rgal.


title:
Constraining the properties of the proposed supermassive black hole
  system in 3c66b: Limits from pulsar timing

abstract:
  Data from long term timing observations of the radio pulsar PSR B1855+09 have
been searched for the signature of Gravitational waves (G-waves) emitted by the
proposed supermassive binary black hole system in 3C66B. For the case of a
circular orbit, the emitted G-waves would generate detectable fluctuations in
the pulse arrival times of PSR B1855+09. General expressions for the expected
timing residuals induced by G-wave emission from a slowly evolving, eccentric,
binary black hole system are derived here for the first time. These waveforms
are used in a Monte-Carlo analysis in order to place limits on the mass and
eccentricity of the proposed black hole system. The reported analysis also
demonstrates several interesting features of a gravitational wave detector
based on pulsar timing.


title:
The Globular Cluster Systems of the Early-type Galaxies NGC3379,
  NGC4406, and NGC4594 and Implications for Galaxy Formation

abstract:
  We have investigated the global properties of the globular cluster (GC)
systems of three early-type galaxies: the Virgo elliptical NGC4406, the field
elliptical NGC3379, and the field S0 galaxy NGC4594. These galaxies were
observed as part of a wide-field CCD survey of the GC populations of a sample
of normal galaxies beyond the Local Group. Images obtained with the Mosaic
detector on the Kitt Peak 4-m provide radial coverage to at least 24', or
70-100 kpc. We use BVR photometry and image classification to select GC
candidates and thereby reduce contamination from non-GCs, and HST data to help
quantify the contamination that remains. The GC systems of all three galaxies
have color distributions with at least two peaks and show modest negative color
gradients. The proportions of blue GCs range from 60-70% of the total
populations. The GC specific frequency (S_N) of NGC4406 is 3.5+/-0.5, 20% lower
than past estimates and nearly identical to S_N for the other Virgo cluster
elliptical included in our survey, NGC4472. S_N for NGC3379 and NGC4594 are
1.2+/-0.3 and 2.1+/-0.3, respectively; these are similar to past values but the
errors have been reduced by a factor of 2-3. We compare our results to models
for the formation of massive galaxies and their GC systems. Of the scenarios we
consider, a hierarchical merging picture -- in which metal-poor GCs form at
high redshift in protogalactic building blocks and metal-rich GC populations
are built up during subsequent gas-rich mergers -- appears most consistent with
the data. [abridged]


title: Arakelian 564: An XMM-Newton view

abstract:
  We report on two XMM-Newton observations of the bright narrow-line Seyfert 1
galaxy Ark 564 taken one year apart (2000 June and 2001 June). The 0.6-10 keV
continuum is well described by a soft blackbody component (kT~140-150 eV) plus
a steep power law (Gamma~2.50-2.55). No significant spectral changes are
observed between the two observations, although the X-ray flux in the second
observation is ~40-50 per cent lower. In both observations we detect a
significant absorption edge at a rest-frame energy of ~0.73 keV, corresponding
to OVII. The presence of the absorption feature is confirmed by a simultaneous
Chandra grating observation in 2000 June, although the best-fitting edge
threshold is at a slightly lower energy in the Chandra data, possibly because
of a different parameterisation of the underlying X-ray continuum. We find
tentative evidence for a broad iron emission line in the 2000 June observation.
The results from an analysis of the power spectral density (PSD) function are
also presented. The present XMM-Newton data support the idea that the PSD shows
two breaks, although the location of the high-frequency break requires further
constraints.


title: A Magnetic Betelgeuse? Numerical Simulations of Non-linear Dynamo Action

abstract:
  Betelgeuse is an example of a cool super-giant displaying brightness
fluctuations and irregular surface structures. Simulations by Freytag et al.
(2002) of the convective envelope of the star have shown that the fluctuations
in the star's luminosity may be caused by giant cell convection. A related
question regarding the nature of Betelgeuse and supergiants in general is
whether these stars may be magnetically active. If so, that may in turn also
contribute to their variability. By performing detailed numerical simulations,
I find that both linear kinematic and non-linear dynamo action are possible and
that the non-linear magnetic field saturates at a value somewhat below
equipartition: in the linear regime there are two modes of dynamo action.


title:
The Angular Momentum Evolution of 0.1-10 Msun Stars From the Birthline
  to the Main Sequence

abstract:
  (Abridged) Projected rotational velocities (vsini) have been measured for a
sample of 145 stars with masses between 0.4 and >10 Msun (median mass 2.1 Msun)
located in the Orion star-forming complex. These measurements have been
supplemented with data from the literature for Orion stars with masses as low
as 0.1 Msun. The primary finding from analysis of these data is that the upper
envelope of the observed values of angular momentum per unit mass (J/M) varies
as M^0.25 for stars on convective tracks having masses in the range ~0.1 to ~3
Msun. This power law extends smoothly into the domain of more massive stars (3
to 10 Msun), which in Orion are already on the ZAMS. This result stands in
sharp contrast to the properties of main sequence stars, which show a break in
the power law and a sharp decline in J/M with decreasing mass for stars with M
<2 Msun. A second result of our study is that this break is seen already among
the PMS stars in our Orion sample that are on radiative tracks, even though
these stars are only a few million years old. A comparison of rotation rates
seen for stars on either side of the convective-radiative boundary shows that
stars do not rotate as solid bodies during the transition from convective to
radiative tracks.


title:
The MACHO Project Large Magellanic Cloud Variable Star Inventory. XIII.
  Fourier Parameters for the First Overtone RR Lyrae Variables and the LMC
  Distance

abstract:
  Fourier coefficents have been derived for the $V$ and $R$ light curves of 785
overtone RR Lyrae variables in 16 MACHO fields near the bar of the LMC. The
$\phi_{31}$ and $R_{21}$ coefficients have been compared with those of the
first overtone RR Lyrae variables in the Galactic globular clusters NGC 6441,
M107, M5, M3, M2, $\omega$ Centauri and M68. The results indicate that many of
the LMC variables have properties similar to the ones in M2, M3, M5 and the
Oosterhoff type I variables in $\omega$ Cen, but they are different from the
Oosterhoff type II variables in $\omega$ Cen. Equations derived from
hydrodynamic pulsation models have been used to calculate the luminosity and
temperature for the 330 bona fide first-overtone variables. The results
indicate that they have $\log L$ in the range 1.6 to $1.8\lsun$ and $\log
T_{eff}$ between 3.85 and 3.87. Based on these temperatures, a mean color
excess $E(V-R) =0.08$ mag, equivalent to $E(B-V)=0.14$ mag, has been estimated
for these 330 stars. The 80 M5-like variables (selected according to their
location in the $\phi_{31}-\log P$ plot) are used to determine a LMC distance.
After correcting for the effects of extinction and crowding, a mean apparent
magnitude $<V_0>=18.99 \pm 0.02$ (statistical) $\pm 0.16$ (systematic) has been
estimated for these 80 stars. Combining this with a mean absolute magnitude
$M_V=0.56\pm 0.06$ for M5-like stars derived from Baade-Wesselink analyses,
main sequence fitting, Fourier parameters and the trigonometric parallax of RR
Lyrae, we derive an LMC distance modulus $\mu=18.43\pm 0.06$ (statistical) $\pm
0.16$ (systematic) mag. The large systematic error arises from the difficulties
of correcting for interstellar extinction and for crowding.


title: The catalogue of OB associations in IC 1613

abstract:
  We present a catalogue of OB associations in IC 1613. Using an automatic and
objective method (Battinelli's 1991 technique) 60 objects were found. The size
distribution reveals a significant peak at about 60 parsecs if a distance
modulus of 24.27 mag is assumed. Spatial distributions of the detected
associations and H II regions are strongly correlated.


title: Radiation Hydrodynamical Evolution of Primordial H II Regions

abstract:
  We simulate the ionization environment of z ~ 20 luminous objects formed
within the framework of the current CDM cosmology and compute their UV escape
fraction. These objects are likely single very massive stars that are copious
UV emitters. We present analytical estimates as well as one--dimensional
radiation hydrodynamical calculations of the evolution of these first HII
regions in the universe. The initially D--type ionization front evolves to
become R--type within $\lesssim 10^5$ yrs at a distance $\sim1$ pc. This
ionization front then completely overruns the halo, accelerating an expanding
shell of gas outward to velocities in excess of 30 km s$^{-1}$, about ten times
the escape velocity of the confining dark matter halo. We find that the
evolution of the HII region depends only weakly on the assumed stellar ionizing
luminosities. Consequently, most of the gas surrounding the first stars will
leave the dark halo whether or not the stars produce supernovae. If they form
the first massive seed black holes these are unlikely to accrete within a
Hubble time after they formed until they are incorporated into larger dark
matter halos that contain more gas. Because these I--fronts exit the halo on
timescales much shorter than the stars' main sequence lifetimes their host
halos have UV escape fractions of $\gtrsim 0.95$, fixing an important parameter
for theoretical studies of cosmological hydrogen reionization.


title: Intrinsic Redshifts in Normal Spiral Galaxies

abstract:
  The Tully-Fisher (TF) relation calibrated in both the B-band and the I-band
indicates that (1) the redshift distribution of Virgo Cluster spirals has a
morphological dependence that is inconsistent with a peculiar velocity
interpretation. (2) Galaxies of morphology similar to ScI galaxies have a
systematic excess redshift component relative to the redshift expected from a
Hubble Constant of 72 km s-1 Mpc-1. (3) Pairs and groups of galaxies exist for
which the TF relation provides excellent agreement among individual members,
but for which the group redshift deviates strongly from the predictions of the
Hubble Relation. It is again found that morphology plays a role as these
galaxies are all of Hubble types Sbc and Sc. The overall results of this study
indicate that normal Sbc and Sc galaxies have a systematic excess redshift
component relative to the predictions of the standard Hubble relation assuming
a Hubble Constant of 72 km s-1 Mpc-1. The excess redshifts identified in this
analysis are consistent with the expectations of previous claims for
non-cosmological (intrinsic) redshifts.


title: Giant pulses in Millisecond Pulsars

abstract:
  Giant pulses (GPs), occasional individual pulses with an intensity 100 times
the average intensity, have been detected in four pulsars todate. Their origin
is not well understood, but studies suggest a connection between the strength
of magnetic field at the light cylinder B_lc and the existence of GPs. Here, we
report on detection of significant Large Amplitude Pulses (LAPs) in two more
pulsars with high values of B_lc, PSRs J0218+4232 and B1957+20, observed using
Giant Meterwave Radio Telescope (GMRT).


title: Clumpy Flows in Protoplanetary and Planetary Nebulae

abstract:
  Many astrophysical flows occur in inhomogeneous media. We briefly discuss
some general properties of the adiabatic and radiative inhomogeneous systems
and discuss the relevance of those properties to the planetary nebulae systems.
We then focus on radiative hypersonic bullets and the applicability of this
model to planetary and protoplanetary systems such as CRL 618, NGC 6543, Hen
3-1475.


title: Magnetic fields in the Milky Way and other spiral galaxies

abstract:
  The average strength of the total magnetic field in the Milky Way, derived
from radio synchrotron data under the energy equipartition assumption, is 6\muG
locally and \simeq 10\muG at 3 kpc Galactic radius. Optical and synchrotron
polarization data yield a strength of the local regular field of \simeq 4\muG
(an upper limit if anisotropic fields are present), while pulsar rotation
measures give \simeq 1.5\muG (a lower limit if small-scale fluctuations in
regular field strength and in thermal electron density are anticorrelated). In
spiral arms of external galaxies, the total [regular] field strength is up to
\simeq 35\muG [\simeq 15\muG]. In nuclear starburst regions the total field
reaches \simeq 50\muG. Little is known about the global field structure in the
Milky Way. The local regular field may be part of a ``magnetic arm'' between
the optical arms, a feature that is known from other spiral galaxies. Unlike
external galaxies, rotation measure data indicate several global field
reversals in the Milky Way, but some of these could be due to field
distortions. The Galaxy is surrounded by a thick radio disk of similar extent
as around many edge-on spiral galaxies. While the regular field of the local
disk is of even symmetry with respect to the plane (quadrupole), the regular
field in the inner Galaxy or in the halo may be of dipole type. The Galactic
center region hosts highly regular fields of up to milligauss strength which
are oriented perpendicular to the plane.


title: Radio characteristics of the very young Planetary Nebulae SAO244567

abstract:
  The radio emission from the youngest known Planetary nebula, SAO244567, has
been mapped at 20,13, 6, 3.6 and 1.2 cm by using the Australian Telescope
Compact Array (ATCA). These observations constitute the first detailed radio
study of this very interesting object, as they allow us to obtain, for the
first time, the radio morphology of the source and to compute the radio
spectrum up to 18752 MHz.


title: Extrasolar "Earths" in habitable zones- targets of opportunity

abstract:
  We have shown that Earth-mass planets could survive in variously restricted
regions of the habitable zones (HZs) of most of a sample of nine of the 102
main-sequence exoplanetary systems confirmed by 25 September 2003. In a
preliminary extrapolation of our results to the other systems, we estimate that
roughly a half of these systems could have had an Earth-mass planet confined to
the HZ for at least the most recent 1000 Ma. The HZ migrates outwards during
the main-sequence lifetime, and so this proportion varies with stellar age;
about two thirds of the systems could have such a planet confined to the HZ for
at least 1000 Ma at sometime during the main-sequence lifetime. Clearly, these
systems should be high on the target list for exploration for terrestrial
planets. We have reached this conclusion by launching putative Earth-mass
planets in various orbits and following their fate with mixed-variable
symplectic and hybrid integrators. Whether the Earth-mass planets could form in
the HZs of the exoplanetary systems is an urgent question that needs further
study.


title: Nuclear pasta structure in hot neutron stars

abstract:
  Structure of cold and hot dense matter at subnuclear densities is
investigated by quantum molecular dynamics (QMD) simulations. Obtained phase
diagrams show that the density of the phase boundaries between the different
nuclear structures decreases with increasing temperature due to the thermal
expansion of nuclear matter region.


title:
First stars IV.CS 29497-030: Evidence for operation of the s-process at
  very low metallicity

abstract:
  We present an abundance analysis of the very metal-poor, carbon-enhanced star
CS 29497-030. Our results indicate that this unusually hot turnoff star (Teff =
6650K, log g = 3.5) has a metallicity [Fe/H] = -2.8, and exhibits large
overabundances of carbon ([C/Fe] = +2.38), nitrogen ([N/Fe]= +1.88), and oxygen
([O/Fe]= +1.67). This star also exhibits a large enhancement in its
neutron-capture elements; the pattern follows that expected to arise from the
s-process. In particular, the Pb abundance is found to be very high with
respect to iron ([Pb/Fe]= +3.5), and also with respect to the second peak
s-process elements (e.g., Ba, La, Ce, Nd), which fits into the newly introduced
classification of lead (Pb) stars. The known spectroscopic binary status of
this star, along with the observed s-process abundance pattern, suggest that it
has accreted matter from a companion, which formerly was an Asymptotic
Giant-Branch(AGB) star. In a preliminary analysis, we have also identified
broad absorption lines of metallic species that suggest a large axial
rotational velocity for this star, which may be the result of spin-up
associated with the accretion of material from its previous AGB companion. In
addition, this star is clearly depleted in the light element Li. When
considered along with its rather high inferred temperature, these observations
are consistent with the expected properties of a very low metallicity halo blue
straggler.


title: Metal Abundances and Kinematics of the Ly-alpha absorbers

abstract:
  Both high resolution spectra of QSOs observed at the 8-10m telescopes and
advanced methods of data analysis are crucial for accurate measurements of the
chemical composition and physical parameters of the intervening clouds. An
overview of our recent results obtained with the Monte Carlo inversion (MCI)
procedure is presented. This includes: (1) variations of the shape of the local
background ionizing continuum in the 1-5 Ryd range at redshift z ~ 2.8-3.0; (2)
an inverse correlation between the measured metallicity, [C/H], and the
absorber line-of-sight linear size, L; (3) a functional dependence between the
line-of-sight velocity dispersion, sigma_v, and L.


title: The merging/AGN connection: A case for 3D spectroscopy

abstract:
  We discuss an ongoing study of the connection between galaxy
merging/interaction and AGN activity, based on integral field spectroscopy. We
focus on the search for AGN ionization in the central regions of mergers,
previously not classified as AGNs. We present here the science case, the
current status of the project, and plans for future observations.


title: Dark Matter at the Center and in the Halo of the Galaxy

abstract:
  All presently known stellar-dynamical constraints on the size and mass of the
supermassive compact dark object at the Galactic center are consistent with a
ball of self-gravitating, nearly non-interacting, degenerate fermions with mass
between 76 and 491 keV, for degeneracy factor g=2. Sterile neutrinos of 76 keV
mass, which are mixed with at least one of the active neutrinos with a mixing
angele ~10^{-7}, are produced in about the right amount in the early Universe
by incoherent resonant and non-resonant scattering of active neutrinos having
asymmetry of ~0.01. The former process yields sterile neutrinos with a
quasi-degenerate spectrum while the latter leads to a thermal spectrum. As the
production mechanism of the sterile neutrino is consistent with the constraints
from large scale structure formation, core collapse supernovae, and diffuse
X-ray background, it could be the dark matter particle of the Universe.


title: Expected properties of radio pulses from lunar EeV neutrino showers

abstract:
  We present results of the simulation of the intensity distribution of radio
pulses from the Moon due to interaction of EeV neutrinos with lunar regolith.
The radiation mechanism is of coherent \^Cerenkov radiation of the negative
charge excess in the shower, known as Askar'yan effect. Several realistic
observational setups with ground radio telescopes are considered. Effective
detector volume is calculated using maximum-knowledge Monte Carlo code, and the
possibilities to set limits on the diffuse neutrino flux are discussed.


title: Quasar Mesolensing - Direct Probe to Substructures around Galaxies -

abstract:
  Recently, ``CDM crisis'' is under discussion. The main point of this crisis
is that number of substructures presented by cosmological N-body simulations
based on CDM scenario for structure formation is much larger than observed
substructures. Therefore, it is crucial for this crisis to discriminate whether
expected number of CDM substructures really exist but non-luminous or do not
exist.
  In this paper, we present a new idea to detect such invisible substructures
by utilizing a gravitational lensing. Here, we consider quasars that are
gravitationally lensed by a foreground galaxy. A substructure around the
lensing galaxy may superposed on one of the lensed images of such quasars. In
this situation, additional image splitting should occur in the image behind the
substructure, and further multiple images are created. This is ``quasar
mesolensing''.
  We estimate separation and time delay between further multiple images due to
quasar mesolensing. The expected value is $1 \sim 30$ milli-arcsecond for the
separation and future fine resolution imaging enable us to find invisible
substructures, and is $1 \sim 10^3$ second for the time delay and high-speed
monitoring of such quasar will be able to find ``echo''-like variation due to
quasar mesolensing in intrinsic variability of the quasar. Furthermore, we
evaluate that the optical depth for the quasar mesolensing is $\sim 0.1$.
Consequently, if we monitor a few multiple quasars, we can find ``echo''-like
variation in one of the images after intrinsic flux variations of quasars.


title: Simulating the high-redshift universe in the sub-mm

abstract:
  I present various simulations of an on-going large sub-mm survey, SHADES,
showing how constraints can be put on galaxy formation models and cosmology
from this survey.


title:
The HELLAS2XMM 1dF survey: on the nature of high X-ray to optical flux
  ratio sources

abstract:
  We present results from the photometric and spectroscopic identification of
122 X-ray sources discovered by XMM-Newton in the 2-10 keV band (the HELLAS2XMM
1dF sample). One of the most interesting results (which is found also in deeper
sourveys) is that ~20% of the sources have an X-ray to optical flux ratio (X/O)
ten times or more higher than that of optically selected AGN. Unlike the faint
sources found in the ultra-deep Chandra and XMM-Newton surveys, which reach
X-ray (and optical) fluxes >~10 times lower than in the HELLAS2XMM sample, many
of the extreme X/O sources in our sample have R~25 and are therefore accessible
to optical spectroscopy. We report the identification of 13 sources with
extreme X/O values. While four of these sources are broad line QSO, eight of
them are narrow line QSO, seemingly the extension to very high luminosity of
the type 2 Seyfert galaxies.


title: BeppoSAX observation of PSR B1937+21

abstract:
  We present the results of a BeppoSAX observation of the fastest rotating
pulsar known: PSR B1937+21. The ~200 ks observation (78.5 ks MECS/34 ks LECS
on-source time) allowed us to investigate with high statistical significance
both the spectral properties and the pulse profile shape. The pulse profile is
clearly double peaked at energies > ~4 keV. Peak widths are compatible with the
instrumental time resolution and the second pulse lags the main pulse 0.52 in
phase, like is the case in the radio. In the 1.3-4 keV band we detect a ~45% DC
component; conversely the 4-10 keV pulsed fraction is consistent with 100%. The
on-pulse spectrum is fitted with an absorbed power-law of spectral index ~1.2,
harder than that of the total flux which is ~1.9. The total unabsorbed (2-10
keV) flux is F_{2-10} = 4.1 10^-13 cgs, implying a luminosity of L_X = 5.0
10^31 \Theta (d/3.6 kpc)^2 erg s^-1 and a X-ray efficiency of \eta = 4.5 10^-5
\Theta, where \Theta is the solid angle spanned by the emission beam. These
results are in agreement with those obtained by ASCA and a more recent
Rossi-XTE observation. The hydrogen column density N_H ~2 10^22 cm^-2 is ~10
times higher than expected from the radio dispersion measure and average
Galactic density of e-. Though it is compatible (within 2\sigma) with the
Galactic (HI derived) value of ~1 10^22 cm^-2, inspection of dust extinction
maps reveal that the pulsar falls in a highly absorbed region. In addition, 1.4
GHz radio map shows that the nearby (likely unrelated) HII source 4C21.53W is
part of a circular emission region ~4' across.


title: Comment on a Quintessence Particle Mass in the Kaluza-Klein Theory

abstract:
  We calculate a mass of a quintessence particle of order 0.00001 eV and we
find several solutions for quintessence field equation. We consider also a
quintessence speed of sound in several schemes and quintessence fluctuations.


title: A calibration map for Wide Field Imager photometry

abstract:
  We present a prescription to correct large-scale intensity variations
affecting imaging data taken with the Wide Field Imager (WFI) at the MPG/ESO
2.2 m telescope at the European Southern Observatory at La Silla in Chile. Such
smoothly varying, large-scale gradients are primarily caused by non-uniform
illumination due to stray light, which cannot be removed using standard
flatfield procedures. By comparing our observations to the well-calibrated,
homogeneous multi-colour photometry from the Sloan Digital Sky Survey we
characterise the intensity gradients across the camera by second-order
polynomials. The application of these polynomials to our data removes the
gradients and reduces the overall scatter. We also demonstrate that applying
our correction to an independent WFI dataset significantly reduces its
large-scale variations, indicating that our prescription provides a generally
valid and simple tool for calibrating WFI photometry.


title: Galactic hydraulic drop?

abstract:
  Galaxies and galaxy clusters are observed to have a rather non-trivial radial
behaviour. The observations show that the radial profiles change from one
power-law profile near the centre to another power-law profile in the outer
region. We present a simple explanation for this complex behaviour by finding
the analytical solutions to the governing hydrodynamic equations. We see that
the origin of this complexity is the collisional nature of the baryonic plasma,
possibly related to a turbulence-enhanced viscosity.


title: Science Verification Results from PMAS

abstract:
  PMAS, the Potsdam Multi-Aperture Spectrophotometer, is a new integral field
instrument which was commissioned at the Calar Alto 3.5m Telescope in May 2001.
We report on results obtained from a science verification run in October 2001.
We present observations of the low-metallicity blue compact dwarf galaxy
SBS0335-052, the ultra-luminous X-ray Source X-1 in the Holmberg II galaxy, the
quadruple gravitational lens system Q2237+0305 (the "Einstein Cross"), the
Galactic planetary nebula NGC7027, and extragalactic planetary nebulae in M31.
PMAS is now available as a common user instrument at Calar Alto Observatory.


title:
Magnetic Braking and Viscous Damping of Differential Rotation in
  Cylindrical Stars

abstract:
  Differential rotation in stars generates toroidal magnetic fields whenever an
initial seed poloidal field is present. The resulting magnetic stresses, along
with viscosity, drive the star toward uniform rotation. This magnetic braking
has important dynamical consequences in many astrophysical contexts. For
example, merging binary neutron stars can form "hypermassive" remnants
supported against collapse by differential rotation. The removal of this
support by magnetic braking induces radial fluid motion, which can lead to
delayed collapse of the remnant to a black hole. We explore the effects of
magnetic braking and viscosity on the structure of a differentially rotating,
compressible star, generalizing our earlier calculations for incompressible
configurations. The star is idealized as a differentially rotating, infinite
cylinder supported initially by a polytropic equation of state. The gas is
assumed to be infinitely conducting and our calculations are performed in
Newtonian gravitation. Though highly idealized, our model allows for the
incorporation of magnetic fields, viscosity, compressibility, and shocks with
minimal computational resources in a 1+1 dimensional Lagrangian MHD code. Our
evolution calculations show that magnetic braking can lead to significant
structural changes in a star, including quasistatic contraction of the core and
ejection of matter in the outermost regions to form a wind or an ambient disk.
These calculations serve as a prelude and a guide to more realistic MHD
simulations in full 3+1 general relativity.


title: A most energetic type Ic supernova: SN 2003L

abstract:
  We present extensive radio observations of SN 2003L, the most luminous and
energetic Type Ic radio supernova with the exception of SN 1998bw. Using radio
data, we are able to constrain the physical parameters of the supernova,
including the velocity and energy of the fastest ejecta, the temporal evolution
of the magnetic field, and the density profile of the surrounding medium. We
highlight the extraordinary properties of the radio emission with respect to
the supernova's normal characteristics within optical bands. We find that
although the explosion does not show evidence for a significant amount of
relativistic ejecta, it produces a radio luminosity which is comparable to that
seen in the unusual SN 1998bw. Using SN 2003L as an example, we comment briefly
on the broad diversity of type Ic properties and the associated implications
for progenitor models.


title: Statistics of Giant Arcs in Galaxy Clusters

abstract:
  We study the expected properties and statistics of giant arcs produced by
galaxy clusters in a LambdaCDM universe and investigate how the characteristics
of CDM clusters determine the properties of the arcs they generate. Due to the
triaxiality and substructure of CDM halos, the giant arc cross section for
individual clusters varies by more than an order of magnitude as a function of
viewing angle. In addition, the shallow density cusps and triaxiality of CDM
clusters cause systematic alignments of giant arcs which should be testable
with larger samples from forthcoming lensing surveys. We compute the predicted
statistics of giant arcs for the LambdaCDM model and compare to results from
previous surveys. The predicted arc statistics are in excellent agreement with
the numbers of giant arcs observed around low redshift (0.2 < z < 0.6) clusters
from the EMSS sample, however there are hints of a possible excess of arcs
observed around high redshift z > 0.6 clusters. This excess, if real, appears
to be due to the presence of highly massive or concentrated clusters at high
redshifts.


title: Testing Lorentz Invariance with GRB021206

abstract:
  Since the discovery of the cosmological origin of GRBs there has been growing
interest in using these transient events to probe the quantum gravity energy
scale in the range 10^16--10^19 GeV, up to the Planck mass scale. This energy
scale can manifest itself through a measurable modification in the
electromagnetic radiation dispersion relation for high energy photons
originating from cosmological distances. We have used data from the gamma-ray
burst (GRB) of 6 December 2002 (GRB021206) to place an upper bound on the
energy dispersion of the speed of light. The limit on the first-order quantum
gravity effects derived from this single GRB indicate that the energy scale is
in excess of 1.8x10^17 GeV. We discuss a program to further constrain the
energy scale by systematically studying such GRBs.


title:
Recent Results from HEGRA (Gamma-Ray Observations with the HEGRA
  Stereoscopic System of 5 Cherenkov Telescopes)

abstract:
  The HEGRA collaboration has achieved outstanding results during the operation
of the six imaging atmospheric Cherenkov telescopes from 1996 to 2002. The
experimental work pioneered the field of TeV gamma-ray astronomy with
observations during partial moon time and mainly by applying the stereoscopic
observation mode using a system of five Cherenkov telescopes.
  Concerning Galactic objects the HEGRA observations have led to a precise
measurement of the energy spectrum of the Crab nebula between 0.5 and 80 TeV,
the detection of the first shell type supernova remnant in the Northern
hemisphere (Cassiopeia A) and the investigation of the yet unidentified HEGRA
TeV gamma-ray source TeV J2032+4130 in the Cygnus region. In addition, a large
fraction of the Galactic plane has been studied during dedicated scans.
  Following the most precise measurements of the energy spectra of the well
known extragalactic objects Mkn 421 and Mkn 501, the blazars H 1426+428 and 1ES
1959+650 have just been established as sources of TeV photons in the last two
years. Extensive multi-wavelength campaigns have been successfully performed
and spectroscopy of these four objects gives important clues for the
understanding of the nonthermal emission processes and also on the optical to
infrared part of the spectrum of the extragalactic background light. Recently,
strong evidence for the nearby giant radio galaxy M 87 being a TeV gamma-ray
emitter has been obtained.
  Some of these results are highlighted in this article.


title: X-ray Observations of Planetary Nebulae

abstract:
  Planetary nebulae (PNe) are an exciting addition to the zoo of X-ray sources.
Recent Chandra and XMM-Newton observations have detected diffuse X-ray emission
from shocked fast winds in PN interiors as well as bow-shocks of fast
collimated outflows impinging on the nebular envelope. Point X-ray sources
associated with PN central stars are also detected, with the soft X-ray (<0.5
keV) emission originating from the photospheres of stars hotter than ~100,000
K, and the hard X-ray (>>0.5 keV) emission from instability shocks in the fast
stellar wind itself or from a low-mass companion's coronal activity. X-ray
observations of PNe offer a unique opportunity to directly examine the dynamic
effects of fast stellar winds and collimated outflows, and help us understand
the formation and evolution of PNe.


title: Hot Gas in Planetary Nebulae

abstract:
  Diffuse X-ray emission has been detected in a small number of planetary
nebulae (PNe), indicating the existence of shocked fast stellar winds and
providing support for the interacting-stellar-winds formation scenario of PNe.
However, the observed X-ray luminosities are much lower than expected, similar
to the situation seen in bubbles or superbubbles blown by massive stars. Ad hoc
assumptions have been made to reconcile the discrepancy between observations
and theoretical expectations. We have initiated FUSE programs to observe OVI
absorption and emission from PNe, and our preliminary results indicate that OVI
emission provides an effective diagnostic for hot gas in PN interiors.


title: Bubbles and Superbubbles

abstract:
  An isolated massive star can blow a bubble, while a group of massive stars
can blow superbubbles. In this paper, we examine three intriguing questions
regarding bubbles and superbubbles: (1) why don't we see interstellar bubbles
around every O star? (2) how hot are the bubble interiors? and (3) what is
going on at the hot/cold gas interface in a bubble?


title: Hard X-ray Emission Associated with White Dwarfs II

abstract:
  We have previously conducted a search for X-ray sources coincident with white
dwarfs using the white dwarf catalog compiled by McCook & Sion (1999} and the
ROSAT sources in the WGACAT (Paper I). To include the white dwarfs discovered
since 1999 and to include the X-ray sources detected in ROSAT Position
Sensitive Proportional Counter (PSPC) observations made with a boron filter, we
have carried out another search using an updated list of white dwarfs and the
final catalogs of the ROSAT PSPC observations with and without a boron filter.
Forty-seven new X-ray sources convincingly coincident with white dwarfs are
found and reported in this paper. Among these, only 5 show hard X-ray emission:
three possess confirmed or suggested late-type companions, one is apparently
single, and the other is likely a misclassified BL Lac object. The apparently
single white dwarf with hard X-ray emission, KPD 0005+5106, was discussed
extensively in Paper I. Photospheric origin for the hard X-ray emission from
hot DO and DQZO white dwarfs remains a tantalizing possibility, but
high-quality near IR spectroscopic observations and monitoring of the H-alpha
emission line are needed to rule out the existence of a faint dMe companion.


title:
An Intriguing X-ray Arc Surrounding the X-ray Source RX J053335-6854.9
  toward the Large Magellanic Cloud

abstract:
  ROSAT observations of the Large Magellanic Cloud (LMC) have revealed a large
diffuse X-ray arc around the point source RX J053335-6854.9. The relative
locations of the diffuse and point sources suggest that they might originate
from a common supernova explosion. We have analyzed the physical properties of
the diffuse X-ray emission and determined that it is most likely a supernova
remnant in a low-density medium in the LMC. We have also analyzed the X-ray and
optical observations of RX J053335-6854.9 and concluded that it is a foreground
dMe star in the solar neighborhood. Therefore, despite their positional
coincidence, these two X-ray sources are physically unrelated.


title: Detection of Molecular Hydrogen Emission Associated with LkHalpha 264

abstract:
  We have detected emission of molecular hydrogen from a classical T Tauri
star, LkHalpha 264 in the v=1-0 S(1) line at 2.122 micron. The line velocity is
coincident with the rest velocity of the star. The line profile is well
reproduced by a model in which the line emanates from material in a Keplerian
rotating circumstellar disk. Fluorescence by X-ray ionization and shock
excitation due to accretion or a low-velocity wind are considered for the
emission mechanism of molecular hydrogen.


title: Faint 1.4 GHz sources in the 2dF Galaxy Redshift Survey

abstract:
  The Australia Telescope Compact Array (ATCA) has been used to survey at
1.4GHz, a small region (< 3 sq deg) overlapping with the 2dF Galaxy Redshift
Survey (Colless et al. 2001, MNRAS, 328, 1039). We surveyed with a varying
radio sensitivity, ranging from 1mJy - 20microJy (1 sigma). There are 365
2dFGRS sources with z > 0.001 lying within the surveyed region, of which 316
have reliable spectral classification. Following Sadler et al. 2002 (MNRAS,
329, 227), we visually classified 176 as AGN or early-type galaxies, and 140 as
star-forming galaxies. We derived radio flux density measurement or upperlimits
for each of the 365 2dFGRS sources. The fraction of radio detected 2dFGRS
star-forming galaxies increases from ~ 50% at ~ 0.7mJy up to ~ 60% at ~ 0.2mJy.
The mean redshift for the fraction of radio detected star-forming galaxies
increases with increasing radio detection sensitivity, while the mean redshift
is fairly constant for the AGN/early-type fraction. We found very similar radio
detection rates of 2dFGRS galaxies for both the AGN/early-type and star-forming
components. The radio detection rate increases approximately linearly with
respect to the rate of increase in radio detection sensitivity. We derived the
radio luminosity function for our sample and it was found to be consistent with
that of Sadler et al. 2002. We have also compared the total flux densities of
NVSS sources common to our survey, and we discuss strategies for a large-scale
radio survey of the 2dFGRS sample.


title:
The CORALIE survey for southern extra-solar planets. XII. Orbital
  solutions for 16 extra-solar planets discovered with CORALIE

abstract:
  This paper summarizes the information gathered for 16 still unpublished
exoplanet candidates discovered with the CORALIE echelle spectrograph mounted
on the Euler Swiss telescope at La Silla Observatory. Amongst these new
candidates, 10 are typical extrasolar Jupiter-like planets on intermediate- or
long-period (100<P<1350d) and fairly eccentric (0.2<e<0.5) orbits (HD19994,
HD65216, HD92788, HD111232, HD114386, HD142415, HD147513, HD196050, HD216437,
HD216770). Two of these stars are in binary systems. The next 3 candidates are
shorter-period planets (HD6434, HD121504) with lower eccentricities among which
a hot Jupiter (HD83443). More interesting cases are finally given by the
multiple-planet systems HD82943 and HD169830. The former is a resonant
P_2/P_1=2/1 system in which planet-planet interactions are influencing the
system evolution. The latter is more hierarchically structured.


title:
An ISOCAM survey through gravitationally lensing galaxy clusters. IV.
  Luminous infrared galaxies in Cl 0024+1654 and the dynamical status of
  clusters

abstract:
  Observations of the core of the massive cluster Cl 0024+1654, at a redshift
z=0.39, were obtained with the Infrared Space Observatory using ISOCAM at 6.7
mum and 14.3 mum (hereafter 15 mum). Thirty five sources were detected at 15
mum and thirteen of them are spectroscopically identified with cluster
galaxies. The remaining sources consist of four stars, one quasar, one
foreground galaxy, three background galaxies and thirteen sources with unknown
redshift. The ISOCAM sources have best-fit SEDs typical of spiral or starburst
models observed 1 Gyr after the main starburst event. The median infrared
luminosity of the twelve cluster galaxies is 1.0x10^11 Lsun, with 10 having
infrared luminosity above 9x10^10 Lsun, and so lying near or above the 1x10^11
Lsun threshold for identification as a luminous infrared galaxy (LIRG). The
[OII] star formation rates obtained for 3 cluster galaxies are one to two
orders of magnitude lower than the infrared values, implying that most of the
star formation is missed in the optical because it is enshrouded by dust in the
starburst galaxy. The counterparts of about half of the 15 mum cluster sources
are blue, luminous, star-forming systems and the type of galaxy that is usually
associated with the Butcher-Oemler effect. Dust obscuration may be a major
cause of the 15 mum sources appearing on the cluster main sequence. The
majority of the ISOCAM sources in the Butcher-Oemler region of the
colour-magnitude diagram are best fit by spiral-type SEDs whereas
post-starburst models are preferred on the main sequence, with the starburst
event probably triggered by interaction with one or more galaxies. Finally, the
mid-infrared results on Cl 0024+1654 are compared with four other clusters
observed with ISOCAM.


title:
Constraining Variations in the Fine-structure Constant, Quark Masses and
  the Strong Interaction

abstract:
  We present evidence for variations in the fine-structure constant from
Keck/HIRES spectra of 143 quasar absorption systems over the redshift range 0.2
< z_abs < 4.2. This includes 15 new systems, mostly at high-z (z_abs > 1.8).
Our most robust estimate is a weighted mean da/a=(-0.57 +/- 0.11)x10^{-5}. We
respond to recent criticisms of the many-multiplet method used to extract these
constraints. The most important potential systematic error at low-z is the
possibility of very different Mg heavy isotope abundances in the absorption
clouds and laboratory: {\it higher} abundances of {25,26}Mg in the absorbers
may explain the low-z results. Approximately equal mixes of {24}Mg and
{25,26}Mg are required. Observations of Galactic stars generally show {\it
lower} {25,26}Mg isotope fractions at the low metallicities typifying the
absorbers. Higher values can be achieved with an enhanced population of
intermediate mass stars at high redshift, a possibility at odds with observed
absorption system element abundances. At present, all observational evidence is
consistent with the varying-alpha results.
  Another promising method to search for variation of fundamental constants
involves comparing different atomic clocks. Here we calculate the dependence of
nuclear magnetic moments on quark masses and obtain limits on the variation of
alpha and m_q/Lambda_QCD from recent atomic clock experiments with hyperfine
transitions in H, Rb, Cs, Hg+ and an optical transition in Hg+.


title: Stellar Coronal Spectroscopy with the Chandra HETGS

abstract:
  Spectroscopy with the Chandra High Energy Transmission Grating Spectrometer
provides details on X-ray emission and activity from young and cool stars
through resolution of emission lines from a variety of ions. We are beginning
to see trends in activity regarding abundances, emission measures, and
variability. Here we contrast spectra of TV Crt, a weak-lined T Tauri star,
with TW Hya, a Classical T Tauri star. TV Crt has a spectrum more like magnetic
activity driven coronae, relative to the TW Hya spectrum, which we have
interpreted as due to accretion-produced X-rays. We have also observed the long
period system, IM Pegasi to search for rotational modulation, and to compare
activity in a long period active binary to shorter period systems and to the
pre-main sequence stars. We detected no rotational modulation, but did see
long-duration flares.


title:
The nature of GRB980425 and the search for off-axis GRB signatures in
  nearby type Ib/c supernovae emission

abstract:
  The identification of type Ib/c supernovae as GRB progenitors is motivated by
the association of GRB980425 with SN1998bw and of GRB030329 with SN2003dh.
While the gamma-ray luminosity of GRB030329 was typical to cosmological GRBs,
the luminosity of the nearby (40 Mpc) GRB980425 was ~5 orders of magnitude
lower. The large luminosity difference is commonly explained by hypothesizing
that either SNe Ib/c produce two different classes of GRBs, or that GRB980425
was a typical cosmological GRB jet viewed off-axis. In the latter scenario,
strong radio emission, ~10^{30} erg/s Hz, is expected at ~1 yr delay due to jet
deceleration to sub-relativistic speed, as observed from GRB970508. The radio
luminosity of SN1998bw was 3 orders of magnitude lower than this value. We show
that the low radio flux may be consistent with the off-axis jet interpretation,
if the density of the wind surrounding the progenitor is lower than typically
expected, \dot{m}=(\dot{M}/10^{-5} M_sun/yr)/(v/10^3 km/s)~0.1 instead of
\dot{m}>=1. The lower value of \dot{m} is consistent with the observed radio
emission from the supernova shock driven into the wind. This interpretation
predicts transition to sub-relativistic expansion at ~10 yr delay, with current
\~1 mJy 10GHz flux and m_V~23 optical flux, and with ~10 mas angular source
size. It also implies that in order to search for the signature of off-axis
GRBs associated with nearby Ib/c supernovae, follow up observations should be
carried on a multi-yr time scale.


title: Evolution of Planetary Systems in Resonance

abstract:
  We study the time evolution of two protoplanets still embedded in a
protoplanetary disk. The results of two different numerical approaches are
presented and compared. In the first approach, the motion of the disk material
is computed with viscous hydrodynamical simulations, and the planetary motion
is determined by N-body calculations including exactly the gravitational forces
exerted by the disk material. In the second approach, only the N-body
integration is performed but with additional dissipative forces included such
as to mimic the effect of the disk torques acting on the disk. This type of
modeling is much faster than the full hydrodynamical simulations, and gives
comparative results provided that parameters are adjusted properly.
  Resonant capture of the planets is seen in both approaches, where the order
of the resonance depends on the properties of the disk and the planets.
Resonant capture leads to a rise in the eccentricity and to an alignment of the
spatial orientation of orbits. The numerical results are compared with the
observed planetary systems in mean motion resonance (Gl 867, HD 82943, and 55
Cnc). We find that the forcing together of two planets by their parent disk
produces resonant configurations similar to those observed, but that
eccentricity damping greater than that obtained in our hydrodynamic simulations
is required to match the GJ 876 observations.


title: Radiatively inefficient MHD accretion-ejection structures

abstract:
  We present magnetohydrodynamic simulations of a resistive accretion disk
continuously launching transmagnetosonic, collimated jets. We time-evolve the
full set of magnetohydrodynamic equations, but neglect radiative losses in the
energetics (radiatively inefficient). Our calculations demonstrate that a jet
is self-consistently produced by the interaction of an accretion disk with an
open, initially bent large-scale magnetic field. A constant fraction of heated
disk material is launched in the inner equipartition disk regions, leading to
the formation of a hot corona and a bright collimated, super-fastmagnetosonic
jet. We illustrate the complete dynamics of the ``hot'' near steady-state
outflow (where thermal pressure $\simeq$ magnetic pressure) by showing force
balance, energy budget and current circuits. The evolution to this near
stationary state is analyzed in terms of the temporal variation of energy
fluxes controlling the energetics of the accretion disk. We find that unlike
advection-dominated accretion flow, the energy released by accretion is mainly
sent into the jet rather than transformed into disk enthalpy. These magnetized,
radiatively inefficient accretion-ejection structures can account for
under-luminous thin disks supporting bright fast collimated jets as seen in
many systems displaying jets (for instance M87).


title: The electromagnetic signature of black hole ringdown

abstract:
  We investigate generation of electromagnetic radiation by gravitational waves
interacting with a strong magnetic field in the vicinity of a vibrating
Schwarzschild black hole. Such an effect may play an important role in
gamma-ray bursts and supernovae, their afterglows in particular. It may also
provide an electromagnetic counterpart to gravity waves in many situations of
interest, enabling easier extraction and verification of gravity wave waveforms
from gravity wave detection. We set up the Einstein-Maxwell equations for the
case of odd parity gravity waves impinging on a static magnetic field as a
covariant and gauge-invariant system of differential equations which can be
integrated as an initial value problem, or analysed in the frequency domain. We
numerically investigate both of these cases. We find that the black hole
ringdown process can produce substantial amounts of electromagnetic radiation
from a dipolar magnetic field in the vicinity of the photon sphere.


title: Globular Clusters in Early-Type Galaxies with GMOS

abstract:
  We present recent results from our long-term Gemini/GMOS study of globular
clusters in early-type galaxies. To date, we have obtained photometry and
spectroscopy for clusters in NGCs 3379, 4649, 524, 7332, and IC 1459. We find a
clear bimodality in the NGC 4649 cluster colour distribution, with the fraction
of blue/red clusters increasing with galactocentric radius. We derive ages and
metallicities for 22 clusters in NGC 3379, finding that most of the clusters
appear old (10-15 Gyr); however, there is a group of 4 metal-rich, younger
clusters with ages of 2-6 Gyr. The NGC 3379 cluster velocity dispersion
decreases with radius, as does the inferred (local) mass-to-light ratio: there
is no evidence for a dark matter halo in NGC 3379 based on our globular cluster
data.


title: A Phenomenological Model for QSOs

abstract:
  Using LBQS data, it seems that the predictions of the model is confirmed by
observations. The behavior of comoving density versus redshift is consistent
with LDDE for QSQs. Considering the cosmic evolution of SFR, a unified aspect
for origin and evolution of QSOs and ordinary galaxies is implied by this
model.


title: Thin and Thick Galactic Disks

abstract:
  Studies of elemental abundances in stars belonging to the thin and the thick
disk of our Galaxy are reviewed. Edvardsson et al. (1993) found strong evidence
of [alpha/Fe] variations among F and G main sequence stars with the same [Fe/H]
and interpreted these differences as due to radial gradients in the star
formation rate in the Galactic disk. Several recent studies suggest, however,
that the differences are mainly due to a separation in [alpha/Fe] between thin
and thick disk stars, indicating that these populations are discrete Galactic
components, as also found from several kinematical studies. Further evidence of
a chemical separation between the thick and the thin disk is obtained from
studies of [Mn/Fe] and the ratio between r- and s-process elements. The
interpretation of these new data in terms of formation scenarios and time
scales for the disk and halo components of our Galaxy is discussed.


title:
Quasi-Local Evolution of the Cosmic Gravitational Clustering in Halo
  Model

abstract:
  We show that the nonlinear evolution of the cosmic gravitational clustering
is approximately spatial local in the $x$-$k$ (position-scale) phase space if
the initial perturbations are Gaussian. That is, if viewing the mass field with
modes in the phase space, the nonlinear evolution will cause strong coupling
among modes with different scale $k$, but at the same spatial area $x$, while
the modes at different area $x$ remain uncorrelated, or very weakly correlated.
We first study the quasi-local clustering behavior with the halo model, and
demonstrate that the quasi-local evolution in the phase space is essentially
due to the self-similar and hierarchical features of the cosmic gravitational
clustering. The scaling of mass density profile of halos insures that the
coupling between $(x-k)$ modes at different physical positions is substantially
suppressed. Using high resolution N-body simulation samples in the LCDM model,
we justify the quasi-locality with the correlation function between the DWT
(discrete wavelet transform) variables of the cosmic mass field. Although the
mass field underwent a highly non-linear evolution, and the DWT variables
display significantly non-Gaussian features, there are almost no correlations
among the DWT variables at different spatial positions. Possible applications
of the quasi-locality have been discussed.


title: Sulphur-bearing species in the star forming region L1689N

abstract:
  We report observations of the expected main S-bearing species (SO, SO2 and
H2S) in the low-mass star forming region L1689N. We obtained large scale
(~300''x200'') maps of several transitions from these molecules with the goal
to study the sulphur chemistry, i.e. how the relative abundances change in the
different physical conditions found in L1689N. We identified eight interesting
regions, where we carried out a quantitative comparative study: the molecular
cloud (as reference position), five shocked regions caused by the interaction
of the molecular outflows with the cloud, and the two protostars IRAS16293-2422
and 16293E. In the cloud we carefully computed the gas temperature and density
by means of a non-LTE LVG code, while in other regions we used previous
results. We hence derived the column density of SO, SO2 and H2S, together with
SiO and H2CO - which were observed previously - and their relevant abundance
ratios. We find that SiO is the molecule that shows the largest abundance
variations in the shocked regions, whereas S-bearing molecules show more
moderate variations. Remarkably, the region of the brightest SiO emission in
L1689N is undetected in SO2, H2S and H2CO and only marginally detected in SO.
In the other weaker SiO shocks, SO2 is enhanced with respect to SO. We propose
a schema in which the different molecular ratios correspond to different ages
of the shocks. Finally, we find that SO, SO2 and H2S have significant abundance
jumps in the inner hot core of IRAS16293-2422 and discuss the implications of
the measured abundances.