title:
An intriguing correlation between the masses and periods of the
  transiting planets

abstract:
  We point out an intriguing relation between the masses of the transiting
planets and their orbital periods. For the six currently known transiting
planets, the data are consistent with a decreasing linear relation. The other
known short-period planets, discovered through radial-velocity techniques, seem
to agree with this relation. We briefly speculate about a tentative physical
model to explain such a dependence.


title:
Cosmic microwave background constraints on dark energy dynamics:
  analysis beyond the power spectrum

abstract:
  We consider the distribution of the non-Gaussian signal induced by weak
lensing on the primary total intensity cosmic microwave background (CMB)
anisotropies. Our study focuses on the three point statistics exploiting an
harmonic analysis based on the CMB bispectrum. By considering the three
multipoles as independent variables, we reveal a complex structure of peaks and
valleys determined by the re-projection of the primordial acoustic oscillations
through the lensing mechanism. We study the dependence of this system on the
expansion rate at the epoch in which the weak lensing power injection is
relevant, probing the dark energy equation of state at redshift corresponding
to the equivalence with matter or higher ($w_\infty$). We evaluate the impact
of the bispectrum observable on the CMB capability of constraining the dark
energy dynamics. We perform a maximum likelihood analysis by varying the dark
energy abundance, the present equation of state $w_0$ and $w_\infty$. We show
that the projection degeneracy affecting a pure power spectrum analysis in
total intensity is broken if the bispectrum is taken into account. For a
Planck-like experiment, assuming nominal performance, no foregrounds or
systematics, and fixing all the parameters except $w_0$, $w_\infty$ and the
dark energy abundance, a percent and ten percent precision measure of $w_0$ and
$w_\infty$ is achievable from CMB data only. These results indicate that the
detection of the weak lensing signal by the forthcoming CMB probes may be
relevant to gain insight into the dark energy dynamics at the onset of cosmic
acceleration.


title: Adiabatic and entropy perturbations with interacting fluids and fields

abstract:
  We develop a gauge-invariant formalism for the study of density perturbations
in a Friedmann-Robertson-Walker universe with multiple interacting fluids
and/or scalar fields. We show how N scalar fields may be described by N kinetic
fluids (with maximally stiff equation of state) interacting with a
non-dynamical potential (with vacuum equation of state). We split generic
perturbations into adiabatic and entropic parts, and give the coupled
first-order evolution equations on all scales, including energy and momentum
exchange. We identify the non-adiabatic effects on large scales, and define
adiabatic initial conditions in the presence of multiple fluids and fields.


title: Region of the anomalous compression under Bondi-Hoyle accretion

abstract:
  We investigate the properties of an axisymmetric non-magnetized gas flow
without angular momentum on a small compact object, in particular, on a
Schwarzschild black hole in the supersonic region near the object; the velocity
of the object itself is assumed to be low compared to the speed of sound at
infinity. First of all, we see that the streamlines intersect (i.e., a caustic
forms) on the symmetry axis at a certain distance $r_x$ from the center on the
front side if the pressure gradient is neglected. The characteristic radial
size of the region, in which the streamlines emerging from the sonic surface at
an angle no larger than $\theta_0$ to the axis intersect, is $\Delta r=
r_x\theta^2_0/3.$ To refine the flow structure in this region, we numerically
compute the system in the adiabatic approximation without ignoring the
pressure. We estimate the parameters of the inferred region with anomalously
high matter temperature and density accompanied by anomalously high energy
release.


title: The dependence of protoplanet migration rates on coorbital torques

abstract:
  We investigate the migration rates of high-mass protoplanets embedded in
accretion discs via two and three-dimensional hydrodynamical simulations. The
simulations follow the planet's radial motion and employ a nested-grid code
that allows for high resolution close to the planet. We concentrate on the
possible role of the coorbital torques in affecting migration rates. We analyse
two cases: (a) a Jupiter-mass planet in a low-mass disc and (b) a Saturn-mass
planet in a high-mass disc. Planet migration in case (b) is much more
susceptible to coorbital torques than in case (a). We find that the coorbital
torques in both cases do not depend sensitively on whether the planet is
allowed to migrate through the disc or is held on a fixed orbit. We also
examine the dependence of the planet's migration rate on the numerical
resolution near the planet. For case (a), numerical convergence is relatively
easy to obtain, even when including torques arising from deep within the
planet's Hill sphere. The migration rate in this case is numerically on order
of the Type II migration rate and much smaller than the Type I rate, if the
disc has 0.01 solar-masses inside 26 AU. Torques from within the Hill sphere
provide a substantial opposing contribution to the migration rate. In case (b),
the gas mass within the Hill sphere is larger than the planet's mass and
convergence is more difficult to obtain. If the torques within the Hill sphere
are ignored, convergence is more easily achieved but the migration rate is
artificially large. At our highest resolution, the migration rate for case (b)
is much less than the Type I rate, but somewhat larger than the Type II rate.


title: Star formation in globules in IC1396

abstract:
  We present a large-scale study of the IC1396 region using new deep NIR and
optical images, complemented by 2MASS data. For ten globules in IC1396 we
determine (H-K, J-H) colour-colour diagrams and identify the young stellar
population. Five of these globules contain a rich population of reddened
objects, most of them probably young stellar objects. Two new HH objects (HH865
and HH864) could be identified by means of [SII] emission, one of them a
parsec-scale flow. Using star counts based on 2MASS data we create an
extinction map of the whole region. This map is used to identify 25 globules
and to estimate their mass. The globule masses show a significant increase with
the distance from the exciting O6.5V star HD206267. We explain this correlation
by the enhanced radiation pressure close to this star, leading to evaporation
of the nearby clouds and hence smaller globule masses. We see evidence that the
radiation from HD206267 has a major impact on the star formation activity in
these globules.


title: Is there an enhancement of muons at sea level from transient events?

abstract:
  In a recent study of a search for enhancements from the galactic center with
muons at sea level using the TUPI muon telescope, we have found several ground
level enhancements (GLEs) as very sharp peaks above the count rate background.
This paper reports a consistent analysis of two GLEs observed in December 2003
and detected after an up-grade of the data acquisition system, which includes a
noise filter and which allows us to verify that the GLEs are not mere
background fluctuations. The main target of this study is a search for the
origin of the GLEs. The results show that one of them has a strong correlation
with a solar flare, while the other has an unknown origin, because there is
neither a satellite report of a solar flare, nor prompt X-ray emission, and nor
a excess of nuclei during the raster scan where the GLE was observed. Even so,
two possibilities are analyzed: the solar flare hypothesis and the gamma ray
burst (GRB) hypothesis. We show, by using the FLUKA Monte Carlo results for
photo-production, that under certain conditions there is the possibility of an
enhancement of muons at sea level from GeV GRBs.


title:
Heated Intracluster Gas and Radio Connections: the Singular case of
  MKW3s

abstract:
  Similarly to other cluster of galaxies previously classified as cooling flow
systems, the Chandra observation of MKW3s reveals that this object has a
complex X-ray structure hosting both a X-ray cavity and a X-ray filament.
Unlike the other clusters, however, the temperature map of the core of MKW3s
shows the presence of extended regions of gas heated above the radially
averaged gas temperature at any radius.
  As the cluster does not show evidences for ongoing major mergers Mazzotta et
al. suggest a connection between the heated gas and the activity of the central
AGN. Nevertheless, due to the lack of high quality radio maps, this
interpretation was controversial.
  In this paper we present the results of two new radio observations of MKW3s
at 1.28GHz and 604MHz obtained at the GMRT. Together with the Chandra
observation and a separate VLA observation at 327MHz from Young, we show
unequivocal evidences for a close connection between the heated gas region and
the AGN activity and we briefly summarize possible implications.


title:
Epicyclic frequencies derived from the effective potential: simple and
  practical formulae

abstract:
  We present and discuss a short and simple derivation of orbital epicyclic
frequencies for circular geodesic orbits in stationary and axially symmetric
spacetimes. Such spacetimes include as special cases analytically known black
hole Kerr and Schwarzschild spacetimes, as well as the analytic Hartle-Thorne
spacetime and all numerically constructed spacetimes relevant for rotating
neutron stars. Our derivation follows directly from energy and angular momentum
conservation and it uses the concept of the effective potential. It has never
been published, except for a few special cases, but it has already become a
part of the common knowledge in the field.


title: Radial Alignment of Cluster Galaxies

abstract:
  We report the discovery of a statistically significant radial alignment of
cluster galaxies in a sample of 85 X-ray selected clusters observed in the
Sloan Digital Sky Survey. The tendency for alignment is a robust feature of our
sample and does not vary significantly with individual cluster or galaxy
properties. We use dynamical arguments to show that a significant fraction of
cluster galaxies should be undergoing a parametric tidal resonance that can
cause their long axes to orient themselves towards the center of the cluster
potential, and therefore tentatively ascribe the observed radial alignment to
this dynamical effect.


title: 13 Color Photometry of Open Cluster M48

abstract:
  This paper presents 13 color CCD intermediate-band spectrophotometry of a
field centered on the open cluster M48 (NGC 2548), from 400nm to nearly 1000nm,
taken with Beijing-Arizona-Taiwan-Connecticut (BATC) Multi-Color Survey
Photometric system. The fundamental parameters of this cluster are derived with
a new method which based on the comparison between the spectral energy
distributions (SEDs) of cluster stars and the theoretical SEDs of Padova
models. We find that the best-fitting age of M48 is 0.32 Gyr, the distance is
780 pc and a reddening E(B-V)=0.04 with a solar metallicity Z=0.019


title:
The Acceleration Mechanism of Resistive MHD Jets Launched from Accretion
  Disks

abstract:
  We analyzed the results of non-linear resistive magnetohydrodynamical (MHD)
simulations of jet formation to study the acceleration mechanism of
axisymmetric, resistive MHD jets. The initial state is a constant angular
momentum, polytropic torus threaded by weak uniform vertical magnetic fields.
The time evolution of the torus is simulated by applying the CIP-MOCCT scheme
extended for resistive MHD equations. We carried out simulations up to 50
rotation period at the innermost radius of the disk created by accretion from
the torus. The acceleration forces and the characteristics of resistive jets
were studied by computing forces acting on Lagrangian test particles. Since the
angle between the rotation axis of the disk and magnetic field lines is smaller
in resistive models than in ideal MHD models, magnetocentrifugal acceleration
is smaller. The effective potential along a magnetic field line has maximum
around $z \sim 0.5r_0$ in resistive models, where $r_0$ is the radius where the
density of the initial torus is maximum. Jets are launched after the disk
material is lifted to this height by pressure gradient force. Even in this
case, the main acceleration force around the slow magnetosonic point is the
magnetocentrifugal force. The power of the resistive MHD jet is comparable to
the mechanical energy liberated in the disk by mass accretion. Joule heating is
not essential for the formation of jets.


title: Cosmology with photometric redshift surveys

abstract:
  We explore the utility of future photometric redshift imaging surveys for
delineating the large-scale structure of the Universe, and assess the resulting
constraints on the cosmological model. We perform two complementary types of
analysis: (1) We quantify the statistical confidence and the accuracy with
which such surveys will be able to detect and measure characteristic features
in the clustering power spectrum such as the acoustic oscillations and the
turnover, in a 'model-independent' fashion. We show for example that a 10,000
deg^2 imaging survey with depth r = 22.5 and photometric redshift accuracy
dz/(1+z) = 0.03 will detect the acoustic oscillations with 99.9% confidence,
measuring the associated preferred cosmological scale with 2% precision. Such a
survey will also detect the turnover with 95% confidence, determining the
corresponding scale with 20% accuracy. (2) By assuming a Lambda-CDM model power
spectrum we calculate the confidence with which a non-zero baryon fraction can
be deduced from such future galaxy surveys. We quantify 'wiggle detection' by
calculating the number of standard deviations by which the baryon fraction is
measured, after marginalizing over the shape parameter. This is typically a
factor of four more significant (in terms of number of standard deviations)
than the 'model-independent' result. We conclude that the precision with which
the clustering pattern may be inferred from future photometric redshift surveys
will be competitive with contemporaneous spectroscopic redshift surveys,
assuming that systematic effects can be controlled. We also note that an
analysis of Luminous Red Galaxies in the Sloan Digital Sky Survey may yield a
marginal detection of acoustic oscillations in the imaging survey, in addition
to that recently reported for the spectroscopic component.


title: Chemical Abundances and Milky Way Formation

abstract:
  Stellar chemical element ratios have well-defined systematic trends as a
function of abundance, with an excellent correlation of these trends with
stellar populations defined kinematically. This is remarkable, and has
significant implications for Galactic evolution. The source function, the
stellar Initial Mass Function, must be nearly invariant with time, place and
metallicity. Each forming star must see a well-mixed mass-averaged IMF yield,
implying low star formation rates, with most star formation in at most a few
regions of similar evolutionary history. These well-established results are
difficult to reconcile with standard hierachical formation models, which
assemble many stellar units: galaxy evolution seems to have been dominated by
gas assembly, with subsequent star formation. Recent results, and some new
ones, on the Galactic bulge, stellar halo and thick disk t hat justify this
conclusion are presented.


title: Alternative Detection Methods for Highest Energy Neutrinos

abstract:
  Several experimental techniques are currently under development, to measure
the expected tiny fluxes of highest energy neutrinos above 10**18 eV. Projects
in different stages of realisation are discussed here, which are based on
optical and radio as well as acoustic detectors. For the detection of neutrino
events in this energy range a combination of different detector concepts in one
experiment seems to be most promising.


title: Physics of accretion in the millisecond pulsar XTE J1751-305

abstract:
  We have undertaken an extensive study of X-ray data from the accreting
millisecond pulsar XTE J1751-305 observed by RXTE and XMM-Newton during its
2002 outburst. In all aspects this source is similar to a prototypical
millisecond pulsar SAX J1808.4-3658, except for the higher peak luminosity of
13 per cent of Eddington, and the optical depth of the hard X-ray source larger
by factor ~2. Its broad-band X-ray spectrum can be modelled by three
components. We interpret the two soft components as thermal emission from a
colder (kT ~ 0.6 keV) accretion disc and a hotter (~1 keV) spot on the neutron
star surface. We interpret the hard component as thermal Comptonization in
plasma of temperature ~40 keV and optical depth of ~1.5 in a slab geometry. The
plasma is heated by the accretion shock as the material collimated by the
magnetic field impacts on to the surface. The seed photons for Comptonization
are provided by the hotspot, not by the disc. The Compton reflection is weak
and the disc is probably truncated into an optically thin flow above the
magnetospheric radius. Rotation of the emission region with the star creates an
almost sinusoidal pulse profile with rms amplitude of 3.3 per cent. The
energy-dependent soft phase lags can be modelled by two pulsating components
shifted in phase, which is naturally explained by a different character of
emission of the optically thick spot and optically thin shock combined with the
action of the Doppler boosting.


title: Creating ultra-compact binaries through stable mass transfer

abstract:
  A binary in which a slightly evolved star starts mass transfer to a neutron
star can evolve towards ultra-short orbital periods under the influence of
magnetic braking. This is called magnetic capture. We investigate in detail for
which initial orbital periods and initial donor masses binaries evolve to
periods less than 30-40 minutes within the Hubble time. We show that only small
ranges of initial periods and masses lead to ultra-short periods, and that for
those only a small time interval is spent at ultra-short periods. Consequently,
only a very small fraction of any population of X-ray binaries is expected to
be observed at ultra-short period at any time. If 2 to 6 of the 13 bright X-ray
sources in globular clusters have an ultra-short period, as suggested by recent
observations, their formation cannot be explained by the magnetic capture
model.


title:
Rayleigh and Solberg criteria reversal near black holes: the optical
  geometry explanation

abstract:
  The familiar Newtonian version of the Rayleigh criterion demands that for
dynamical stability the specific angular momentum should increase with the
increasing circumferential radius of circular trajectories of matter. However,
sufficiently close to a black hole the Rayleigh criterion reverses: in stable
fluids, the angular momentum must decrease with the increasing circumferential
radius. The geometrical reason for this reversal is that the space is so very
strongly warped that it turns inside-out.


title: Looking for prematurely `dying', young, compact radio sources

abstract:
  We present VLBA 1.6, 5, 8.4 and 15 GHz observations of a new sample of weak,
young, compact candidates for radio faders selected from the VLA FIRST survey.
We claim that some, or even the majority of young sources, may be short-lived
phenomena due to a lack of stable fuelling from the black hole and fade before
evolving to large extended objects.


title:
A2255: the First Detection of Filamentary Polarized Emission in a Radio
  Halo

abstract:
  A deep radio observation of the A2255 cluster of galaxies has been carried
out at 1.4 GHz with the Very Large Array synthesis telescope. Thanks to the
excellent (u,v) coverage and sensitivity achieved by our observation, the low
brightness diffuse extended sources in the cluster (radio halo and relic) have
been imaged with unprecedented resolution and dynamic range. We find that the
radio halo has filamentary structures that are strongly polarized. The
fractional linear polarization reaches levels of $\simeq$ 20$-$40% and the
magnetic fields appear ordered on scales of $\sim$400 kpc. This is the first
successful attempt to detect polarized emission from a radio halo and provides
strong evidence that in this cluster the magnetic field is ordered on large
scales.


title: Dust in spiral galaxies: global properties

abstract:
  We present and analyse high-quality SCUBA 850- and 450-um images of 14 local
spiral galaxies, including the detection of dust well out into the extended
disk in many cases. We use these data in conjunction with published far-IR flux
densities from IRAS and ISO, and millimetre-wave measurements from ground-based
facilities to deduce the global properties of the dust in these galaxies; in
particular temperature and mass. We find that simple two-temperature greybody
models of fixed dust emissivity index beta=2 and with typical temperatures of
25 < T(warm) < 40 K and 10 < T(cold) < 20 K provide good fits to the spectral
energy distributions. The dust mass in the cold component correlates with the
mass in atomic hydrogen and the mass in the warm component correlates with the
mass in molecular hydrogen. These results thus fit the simple picture in which
the cold dust is heated predominantly by the interstellar radiation field while
the hot dust is heated predominantly by OB stars in more active regions,
although we argue that there is some mixing. The mean gas-to-dust ratio is
120+/-60, very similar to that found within our own galaxy and roughly a factor
of 10 lower than that derived from IRAS data alone. The gas-to-dust ratios in
the warm, molecular component are on average higher than those in the cold,
atomic component. We compare our modelling results with similar results for
more luminous spiral galaxies selected at far-IR wavelengths and find that
whilst the total dust mass distributions of the two samples are
indistinguishable, they have significantly different dust temperature
distributions in both the warm and cold components. We suggest that this
difference...(abridged)


title: Initial results from SECIS observations of the 2001 eclipse

abstract:
  SECIS observations of the June 2001 total solar eclipse were taken using an
Fe {\sc xiv} 5303 {\AA} filter. Automated tools based on wavelet analysis was
used to detect intensity oscillations on various areas of the images.
Statistical analysis of the detections found in the areas covered by the moon
and the upper corona allowed us to estimate the atmospheric and instrumental
effects on the detection of intensity oscillations. An area of the lower
corona, close to Active Region 9513, was found with a statistically significant
amount of intensity oscillations with periodicity of $\sim7.5s$. The shape of
the wavelet transformation of those detections matches theoretical predictions
of sausage-mode perturbations and for the first time in the SECIS project,
second order oscillations were also detected.


title: Asiago eclipsing binaries program. II. V570 Per

abstract:
  The orbit and physical parameters of the double-lined eclipsing binary V570
Per, discovered by the Hipparcos satellite, are derived with formal errors
better than 1% using high resolution Echelle spectroscopy and B, V
photoelectric photometry. Atmospheric analysis is performed on spectra at
quadrature using synthetic spectroscopy that indicates a [Fe/H]=+0.02+/-0.05
metallicity. V570 Per turns out to be a detached system, with shallow eclipses
of Delta B = Delta V =0.13 mag amplitude at a distance of 123+/-3 pc, in fine
agreement with Hipparcos 117 (lower lim. 104, upper lim. 132) pc distance. V570
Per is composed by unperturbed components of F2 and F5 spectral types and
masses of 1.457+/-0.004 and 1.351+/-0.004 Msun respectively, which do not show
surface activity. Both components are still within the Main Sequence band and
are dynamically relaxed to co-rotation with the orbital motion. The system is
particularly interesting because both components have their masses in the range
where transition occurs between convective and radiative cores, and where
differences between families of stellar evolutionary tracks show appreciable
differences. The position of the components of V570 Per on the
temperature-luminosity plane is compared with Padova, Geneva, Granada and
Teramo-04 theoretical stellar models. The comparison provides different best
fit metallicities and ages, with [Fe/H] ranging from +0.07 to +0.18, and ages
from 0.6 to 1.0 Gyr.


title: A Trend Filtering Algorithm for wide field variability surveys

abstract:
  We show that various systematics related to certain instrumental effects and
data reduction anomalies in wide field variability surveys can be efficiently
corrected by a Trend Filtering Algorithm (TFA) applied to the photometric time
series produced by standard data pipelines. Statistical tests, performed on the
database of the HATNet project, show that by the application of this filtering
method the cumulative detection probability of periodic transits increases by
up to 0.4 for variables brighter than 11 mag with a trend of increasing
efficiency toward brighter magnitudes. We also show that TFA can be used for
the reconstruction of periodic signals by iteratively filtering out systematic
distortions.


title:
The Origin of Complex Behavior of Linearly Polarized Components in
  Parsec-Scale Jets

abstract:
  Evidence that the magnetic fields of extragalactic jets have a significant
fraction of their energy in a random component is briefly summarized, and a
detailed model of evolving, jet polarization structures is constructed, based
on this picture. The evolving magnetic field structure of an oblique shock
complex that forms in a relativistic jet simulation is explored by using
velocity data from the hydrodynamical simulation to advect an initially random
magnetic field distribution. Radiative transfer calculations reveal that
emission from a propagating region of magnetic field, `ordered' by the shock,
and lying approximately transverse to the flow direction, merges with that from
an evolving sheared region at the flow periphery. If such a flow were barely
resolved, observation would suggest evolution from a somewhat oblique, to a
more longitudinal, magnetic field structure with respect to the flow axis,
while higher resolution observations would infer a component following a
non-linear trajectory, and with a magnetic field orientation that rotates
during evolution. This result highlights the ambiguity in interpreting VLBP
data, and illustrates the importance of simulations in providing a framework
for proper interpretation of such data.


title: Effects of Gravitational Lensing in the Double Pulsar System J0737-3039

abstract:
  We investigate the effects of gravitational lensing in the binary pulsar
system J0737-3039. Current measurement of the orbital inclination allows the
millisecond pulsar (A) to pass very close (at R_{min}=4000 km) in projection to
the companion pulsar (B), with R_{min} comparable to the Einstein radius (2600
km). For this separation at the conjunction, lensing causes small (about 10%)
magnification of the pulsar A signal on a timescale of several seconds, and
displaces the pulsar image on the sky plane by about 1200 km. More importantly,
lensing introduces a correction (of several microsec) to the conventional
Shapiro delay formula used in pulsar timing analysis, and gives rise to a
geometric time delay together with the delays associated with the pulsar spin
period. These lensing effects can influence the determination of the system
parameters by both timing and scintillation studies. Given the current
uncertainty in the orbital inclination, more extreme manifestations of lensing
(e.g. magnification by a factor of several) are possible. We compare our
predictions with the existing observations and discuss the possibility of
detecting gravitational lensing signatures in the system. The anomalously high
point in A's lightcurve close to superior conjunction might be caused by
gravitational lensing.


title: Star-forming protoclusters associated with methanol masers

abstract:
  We present a multiwavelength study of five methanol maser sites which are not
directly associated with a strong ($>100$ mJy) radio continuum source: G
31.28+0.06, G 59.78+0.06, G 173.49+2.42 (S231, S233IR), G 188.95+0.89 (S252,
AFGL5180) and G 192.60-0.05 (S255IR). These radio-quiet methanol maser sites
are often interpreted as precursors of ultra-compact \ion{H}{ii} regions or
massive protostar sites. In this work, the environment of methanol masers is
probed from mid-IR to millimetre wavelengths at angular resolutions of
$8''-34''$. Spectral energy distribution (SED) diagrams for each site are
presented, together with mass and luminosity estimates. Each radio-quiet maser
site is always associated with a massive ($>50$ M$_{\odot}$), deeply embedded
($A_v>40$ mag) and very luminous ($>10^4$ S L$_{\odot}$) molecular clump, with
$L_{total}{\propto}M_{gas}^{0.75}$. These physical properties characterise
massive star-forming clumps in earlier evolutionary phases than \ion{H}{ii}
regions. In addition, colder gas clumps seen only at mm-wavelengths are also
found near the methanol maser sites. These colderclumps may represent an even
earlier phase of massive star formation. These results suggest an evolutionary
sequence for massive star formation from a cold clump, seen only at mm
wavelengths, evolving to a hot molecular core with a two-component SED with
peaks at far-IR and mid-IR wavelengths, to an (ultra-compact) \ion{H}{ii}
region. Alternatively, the cold clumps might be clusters of low-mass YSOs, in
formation near the massive star-forming clusters. Finally, the values of the
dust grain emissivity index ($\beta$) range between 1.6 and 1.9.


title:
Implications of a new temperature scale for halo dwarfs on LiBeB and
  chemical evolution

abstract:
  Big bang nucleosynthesis (BBN) and the cosmic baryon density from cosmic
microwave background anisotropies together predict a primordial Li7 abundance a
factor of 2--3 higher than that observed in galactic halo dwarf stars. A recent
analysis of Li7 observations in halo stars, using significantly higher surface
temperature for these stars, found a higher Li plateau abundance. These results
go a long way towards resolving the discrepancy with BBN. Here, we examine the
implications of the higher surface temperatures on the abundances of Be and B
which are thought to have been produced in galactic cosmic-ray nucleosynthesis
by spallation of CNO together with Li (produced in alpha + alpha collisions).
While the Be abundance is not overly sensitive to the surface temperature, the
derived B abundances and more importantly the derived oxygen abundances are
very temperature dependent. If the new temperature scale is correct, the
implied increased abundances of these elements poses a serious challenge to
models of galactic cosmic ray nucleosynthesis and galactic chemical evolution.


title:
The effects of population III stars on the chemical and photometrical
  evolution of ellipticals

abstract:
  We have studied the effects of an hypothetical initial generation containing
very massive stars (M > 100 Msun, pair-creation SNe) on the chemical and
photometric evolution of elliptical galaxies. To this purpose, we have computed
the evolution of a typical elliptical galaxy with luminous mass of the order of
10^11 Msun and adopted chemical evolution models already tested to reproduce
the main features of ellipticals. We have tested several sets of yields for
very massive zero-metallicity stars: these stars should produce quite different
amounts of heavy elements than lower mass stars. We found that the effects of
population III stars on the chemical enrichment is negligible if only one or
two generations of such stars occurred, whereas they produce quite different
results from the standard models if they continuously formed for a period not
shorter than 0.1 Gyr. In this case, the results are at variance with the main
observational constraints of ellipticals such as the average [<alpha/Fe>] ratio
in stars and the integrated colors. Therefore, we conclude that if population
III stars ever existed they must have been present for a very short period of
time and their effects on the following evolution of the parent galaxy must
have been negligible. This effect is minimum if a more realistic model with
initial infall of gas rather than the classic monolithic model is adopted.
Ultimately, we conclude that there is no need to invoke a generation of very
massive stars in ellipticals to explain their chemical and photometric
properties.


title: Cosmological N-Body Simulations

abstract:
  In this review we discuss Cosmological N-Body codes with a special emphasis
on Particle Mesh codes. We present the mathematical model for each component of
N-Body codes. We compare alternative methods for computing each quantity by
calculating errors for each of the components. We suggest an optimum set of
components that can be combined reduce overall errors in N-Body codes.


title: Constraints on the luminosity of the stellar remnant in SNR1987A

abstract:
  We obtain photometric constraints on the luminosity of the stellar remnant in
SNR1987A using XMM-Newton and INTEGRAL data. The upper limit in the 2--10 keV
band based on the XMM-Newton data is L<5*10^{34}erg/s. We note, however, that
the optical depth of the envelope is still high in the XMM-Newton band,
therefore, this upper limit does not constrain the true unabsorbed luminosity
of the central source. The optical depth is expected to be small in the hard
X-ray band of the IBIS telescope aboard the INTEGRAL observatory, therefore it
provides an unobscured look at the stellar remnant. We did not detect
statistically significant emission from SN1987A in the 20-60 keV band with the
upper limit of L<1.1*10^{36}erg/s. We also obtained an upper limit on the mass
of radioactive 44Ti M(44Ti)<10^{-3}Msun.


title: Detection of Two Massive CO Systems in 4C 41.17 at z = 3.8

abstract:
  We have detected CO(4-3) in the z=3.8 radio galaxy 4C 41.17 with the IRAM
Interferometer. The CO is in two massive (M_dyn ~ 6 x 10^10 M_Sun) systems
separated by 1.8" (13 kpc), and by 400 km/s in velocity, which coincide with
two different dark lanes in a deep Ly-alpha image. One CO component coincides
with the cm-radio core of the radio galaxy, and its redshift is close to that
of the HeII AGN line. The second CO component is near the base of a cone-shaped
region southwest of the nucleus, which resembles the emission-line cones seen
in nearby AGN and starburst galaxies. The characteristics of the CO sources and
their mm/submm dust continuum are similar to those found in ultraluminous IR
galaxies and in some high-z radio galaxies and quasars. The fact that 4C 41.17
contains two CO systems is further evidence for the role of mergers in the
evolution of galaxies at high redshift.


title:
Evidence of intense hot(~340K) dust in 3CR radio galaxies The most
  dissipative source of cooling in AGNs

abstract:
  The spectra of the powerful 3CR radio galaxies present a typical distribution
in the far-infrared. From the observed radio to X-ray spectral energy
distribution (SED) templates, we propose to subtract the typical energy
distributions of, respectively, the elliptical galaxy host and the synchrotron
radiation. The resulting SED reveals that the main dust emission is well fitted
by the sum of two blackbody components at the respective temperatures 340K+-50K
and 40K+-16K. When the AGN is active, the energy rate released by hot dust is
much more dissipative than cold dust and stellar emission, even when the
elliptical galaxy emission is maximum at age of ~ 90 Myr. Hot dust appears as a
huge cooling source which implies an extremely short time-scale t(cool). In
balance, with the short gravitational time-scale t(grav) of massive galaxies,
the dissipative self-gravitational models (Rees & Ostriker, 1977) are favoured
for radio sources. They justify the existence of massive radio galaxies at z=4
(Rocca-Volmerange et al., 2004). The synchrotron emission is emitting up to the
X-ray wavelength range, so that strong "EXOs" sources could be assimilated to
3CR radio sources. This analysis applied to ISO and SPITZER data on a larger
sample will statistically confirm these results.


title: The orbits of the extrasolar planets HD 82943 c,b

abstract:
  The published orbits of the planets HD 82943b and HD 82943c correspond to a
system bound to a catastrophic event in less than 100,000 years. Alternative
sets of elements and masses, which fit the available observational data and
correspond to regular motions, are presented in this paper. The planets HD
82943 c,b are in a 2/1 mean-motion resonance and are trapped in the
neighborhood of a (0,0)-apsidal corotation.


title: First detection of dust clouds around R CrB variable stars

abstract:
  From VLT/NACO diffraction-limited images of RY~Sgr, we report the first
direct detection of heterogeneities in the circumstellar envelope of a R
Coronae Borealis variable star. Several bright and very large dust clouds are
seen in various directions at several hundred stellar radii from RY Sgr,
revealing high activity for the ejection of stellar material by R CrB
variables. These observations do support the current interpretation that
optically thick dust clouds are formed around the surface of this type of
variable stars and, when passing between the star and the observer, produce the
huge and sudden declines characterizing these objects in visible light. This is
the first direct confirmation of a scenario proposed about 70 years ago.


title:
Dust temperature and density profiles of AGB and post-AGB stars from
  mid-infrared observations

abstract:
  First mid-infrared images of a sample of AGB and post-AGB carbon stars (V
Hya, IRC +10216, CIT 6 and Roberts 22) obtained at La Silla Observatory (ESO,
Chile) are reported. CIT 6 presents a cometary-like feature clearly seen in the
9.7$\mu$m image, Roberts 22 shows an envelope slightly elongated in the
north-east direction while images of V Hya and IRC+10216 are roughly
spherically symmetric. Using inversion technique, the dust emissivity was
derived from the observed intensity profiles, allowing a determination of the
grain temperature and density distributions inside the envelope for these
stars. Dust masses and mass-loss rates were estimated for V Hya and IRC +10216.
Our results are comparable to those obtained in previous studies if dust grains
have dimensions in the range $\sim$ 0.01 - 0.2 $\mu$m. Color maps suggest the
presence of temperature inhomogeneities in the central regions of the dust
envelopes. In the case of V Hya, an eccentric hot point, which direction
coincides with the jet previously seen in [SII] emission, suggest that we are
observing a material ejected in a previous mass-loss event. Bipolar lobes are
clearly seen in the color maps of Roberts 22 and IRC +10216.


title:
Cosmological Parameter Constraints as Derived from the Wilkinson
  Microwave Anisotropy Probe Data via Gibbs Sampling and the Blackwell-Rao
  Estimator

abstract:
  We study the Blackwell-Rao (BR) estimator of the probability distribution of
the angular power spectrum, P(C_l|d), by applying it to samples of full-sky
no-noise CMB maps generated via Gibbs sampling. We find the estimator, given a
set of samples, to be very fast and also highly accurate, as determined by
tests with simulated data. We also find that the number of samples required for
convergence of the BR estimate rises rapidly with increasing l, at least at low
l. Our existing sample chains are only long enough to achieve convergence at l
less than about 40. In comparison with P(C_l|d) as reported by the WMAP team we
find significant differences at these low l values. These differences lead to
up to approximately 0.5 sigma shifts in the estimates of parameters in a
7-parameter Lambda CDM model with non-zero dn_s/dln(k). Fixing dn_s/dln(k)= 0
makes these shifts much less significant.
  Unlike existing analytic approximations, the BR estimator can be
straightforwardly extended for the case of power spectra from correlated
fields, such as temperature and polarization. We discuss challenges to
extending the procedure to higher l and provide some solutions.


title:
A Search for Narrow Vertical Structures in the Canadian Galactic Plane
  Survey

abstract:
  Worms are defined to be dusty, atomic hydrogen (HI) structures which are
observed in low resolution data to rise perpendicular to the Galactic plane.
Data from the 1'-resolution Canadian Galactic Plane Survey (CGPS) were
systematically searched for narrow vertical HI structures which could be
resolved worms. Another motivation for the search was to explore the scenario
that mushroom-shaped worms like GW123.4-1.5, studied by English and
collaborators, could be generated by a single supernova. However no other
vertical structures of mushroom-shape morphology were found. We also examined
objects previously classified as worm candidates by Koo and collaborators; only
7 have a significant portion of their structure falling in the CGPS range of
l=74 deg to 147 deg, -3.5 deg < b < +5.5 deg. Apart from GW123.4-1.5 we could
not confirm that any of these are coherent structures that extend towards the
Milky Way's halo. However a list of 10 narrow, vertical structures found in our
search is furnished; one structure is >~ 500 pc tall, thus extending from the
Galactic plane into the halo. We provide details about these narrow vertical
structures, including comparisons between HI, radio continuum, IR, and CO
observations. Our search was conducted by visual inspection and we describe the
limitations of this approach since it indicates that only 6 disk-halo features
may exist throughout the Milky Way. We also discuss possible origins of
structures at high latitudes and the relationship between mushroom-shaped
clouds and old supernova remnants.


title: Introduction to galactic dynamos

abstract:
  A review of galactic magnetic fields is given with emphasis on simple
analytical solutions of relevant equations and detailed comparison with
observations. It is shown that mean-field dynamo theory, in its simplest form,
is in a remarkably good agreement with observations of galactic magnetic
fields. It is argued that the disc-halo connection can play crucial role in the
nonlinear evolution of regular magnetic fields in spiral galaxies by driving
flux of magnetic helicity from the disc, thus supporting healthy dynamo action.


title:
A submillimeter line survey of low-mass protostars: prelude to ALMA and
  Herschel

abstract:
  The results from a single-dish molecular line survey of a set of 18 deeply
embedded young stellar objects are summarized. More than 40 lines from 16
different species were observed with the JCMT, Onsala, IRAM 30m and SEST
telescopes. The multi-transition data are analyzed using a temperature and
density structure derived from models of the dust continuum emission. For the
outer envelope (>300 AU), the data indicate a `drop' abundance profile for many
species, with normal abundances in the outer- and innermost regions and highly
depleted abundances in an intermediate zone. This zone is bounded at the outer
than the lifetime of the core, and at the inner edge by the evaporation
temperature of the species involved. In the innermost envelope (<300 AU), all
ices evaporate resulting in jumps in the abundances of complex organic
molecules such as CH3OH. A key project for Herschel will be to survey gas-phase
water in these objects, whose abundance shows extreme variations with
temperature. ALMA wil be able to directly image the chemical variations
throughout the envelope and zoom in on the inner hot core and protoplanetary
disks on scales on tens of AU.


title:
Young Stellar Clusters, WR-type Phenomenon and the Origin of the
  Galactic Center Nonthermal Radio Filaments

abstract:
  Recent observations of the Arches cluster located within a projected distance
of 30 pc from the dynamical center of the Galaxy have shown the presence of
diffuse and discrete X-ray continuum emission, diffuse 6.4keV line emission as
well as thermal and nonthermal radio continuum emission. This young and dense
stellar cluster is also recognized to be within the 95% error circle of an
identified steady source of $\gamma$-ray emission associated with the EGRET
source 3EG J1746--2851. Much of the thermal and nonthermal emission can be
explained by shocked gas resulting from colliding winds originating from
massive binaries within the cluster. In particular, we argue that nonthermal
particles could upscatter the radiation field of the cluster by ICS and account
for the $\gamma$-ray emission. We also consider that the fluorescent 6.4 keV
line emission may be the result of the impact of low-energy relativistic
particles on neutral gas distributed in the vicinity of the cluster. Lastly, we
sketch an interpretation in which young stellar clusters and massive young
binary systems are responsible for the origin of nonthermal radio filaments
found throughout the inner 300pc of the Galaxy. The collimation of the
nonthermal filaments may be done in the colliding wind region by the ionized
surface of individual mass-losing stars of massive binary systems. In this
picture, a WR-type phenomenon is expected to power a central star burst in the
Galactic center in order to account for all the observed filaments.


title: Shapiro delay in the PSR J1640+2224 binary system

abstract:
  We present the results of precision timing observations of the binary
millisecond pulsar PSR J1640+2224. Combining the pulse arrival time
measurements made with the Effelsberg 100-m radio telescope and the Arecibo
305-m radio telescope, we have extended the existing timing model of the pulsar
to search for a presence of the effect of a general-relativistic Shapiro delay
in the data. At the currently attainable precision level, the observed
amplitude of the effect constrains the companion mass to
$m_2=0.15^{+0.08}_{-0.05} M_\sun$, which is consistent with the estimates
obtained from optical observations of the white dwarf companion and with the
mass range predicted by theories of binary evolution. The measured shape of the
Shapiro delay curve restricts the range of possible orbital inclinations of the
PSR J1640+2224 system to $78^{\circ}\le i\le 88^{\circ}$. The pulsar offers
excellent prospects to significantly tighten these constraints in the near
future.


title: Black-Hole Accretion Discs and Jets at Super-Eddington Luminosity

abstract:
  Super-Eddington accretion discs with 3 and 15 dot M_E around black holes with
mass 10 M_sun are examined by two-dimensional radiation hydrodynamical
calculations extending from the inner disc edge to 5*10^4 r_g and lasting up to
\sim 10^6 r_g/c. The dominant radiation-pressure force in the inner region of
the disc accelerates the gas vertically to the disc plane, and jets with 0.2 --
0.4$c$ are formed along the rotational axis. In the case of the lower accretion
rate, the initially anisotropic high-velocity jet expands outward and becomes
gradually isotropic flow in the distant region. The mass-outflow rate from the
outer boundary is as large as \sim 10^{19} -- 10^{23} g s^{-1}, but it is
variable and intermittent with time; that is, the outflow switches occasionally
to inflow in the distant region. The luminosity also varies as \sim 10^{40} --
10^{42} erg s^{-1} on a long time-scale. On the other hand, the jet in the case
of the higher accretion rate maintains its initial anisotropic shape even after
it goes far away. The mass-outflow rate and the luminosity attain to steady
values of 3*10^{19} g s^{-1} and 1.3*10^{40} erg s^{-1}, respectively. In
accordance with the local analysis of the slim accretion disc model, the disc
is thermally unstable in the case of 3 \dot M_E} but stable in the case of 15
\dot M_E. The super-Eddington model with 15 \dot M_E is promising to explain a
small collimation degree of the jet and a large mass-outflow rate observed in
the X-ray source SS 433.


abstract:
  Understanding the fate of merging supermassive black holes in galactic
mergers, and the gravitational wave emission from this process, are important
LISA science goals. To this end, we present results from numerical relativity
simulations of binary black hole mergers using the so-called Lazarus approach
to model gravitational radiation from these events. In particular, we focus
here on some recent calculations of the final spin and recoil velocity of the
remnant hole formed at the end of a binary black hole merger process, which may
constraint the growth history of massive black holes at the core of galaxies
and globular clusters.


title:
ASCA Compilation of X-Ray Properties of Hot Gas in Elliptical Galaxies
  and Galaxy Clusters: Two Breaks in the Temperature Dependences

abstract:
  Utilizing ASCA archival data of about 300 objects of elliptical galaxies,
groups, and clusters of galaxies, we performed systematic measurements of the
X-ray properties of hot gas in their systems, and compiled them in this paper.
The steepness of the luminosity--temperature (LT) relation, $L_{\rm
X}\propto(kT)^{\alpha}$, in the range of $kT=$1.5--15 keV is
$\alpha=3.17\pm0.15$, consistent with previous measurements. In the relation,
we find two breaks at around ICM temperatures of 1 keV and 4 keV:
$\alpha=2.34\pm0.29$ above 4 keV, $3.74\pm0.32$ in 1.5--5 keV, and
$4.03\pm1.07$ below 1.5 keV. Such two breaks are also evident in the
temperature and size relation. The steepness in the LT relation at $kT>4$ keV
is consistent with the scale-relation derived from the CDM model, indicating
that the gravitational effect is dominant in richer clusters, while poorer
clusters suffer non-gravity effects. The steep LT relation below 1 keV is
almost attributed to X-ray faint systems of elliptical galaxies and galaxy
groups. We found that the ICM mass within the scaling radius $R_{1500}$ follows
the relation of $M_{\rm gas}\propto T^{2.33\pm0.07}$ from X-ray faint galaxies
to rich clusters. Therefore, we speculate that even such X-ray faint systems
contain a large-scale hot gas, which is too faint to detect.


title:
Low and intermediate mass star yields: The evolution of carbon
  abundances

abstract:
  We present a set of low and intermediate mass star yields based on a modeling
of the TP--AGB phase which affects the production of nitrogen and carbon. These
yields are evaluated by using them in a Galaxy Chemical Evolution model, with
which we analyze the evolution of carbon abundances. By comparing the results
with those obtained with other yield sets, and with a large amount of
observational data, we conclude that the model using these yields combined with
those from Woosley & Weaver (1995) for massive stars properly reproduce all the
data. The model reproduces well the increase of C/O with increasing O/H
abundances. Since these massive star yields do not include winds, it implies
that these stellar winds might have a smoother dependence on metallicity than
usually assumed and that a significant quantity of carbon proceeds from LIM
stars.


title:
Modelling the spin equilibrium of neutron stars in LMXBs without
  gravitational radiation

abstract:
  In this paper we discuss the spin-equilibrium of accreting neutron stars in
LMXBs. We demonstrate that, when combined with a naive spin-up torque, the
observed data leads to inferred magnetic fields which are at variance with
those of galactic millisecond radiopulsars. This indicates the need for either
additional spin-down torques (eg. gravitational radiation) or an improved
accretion model. We show that a simple consistent accretion model can be
arrived at by accounting for radiation pressure in rapidly accreting systems
(above a few percent of the Eddington accretion rate). In our model the inner
disk region is thick and significantly sub-Keplerian, and the estimated
equilibrium periods are such that the LMXB neutron stars have properties that
accord well with the galactic millisecond radiopulsar sample. The implications
for future gravitational-wave observations are also discussed briefly.


title: How viscous is a superfluid neutron star core?

abstract:
  We discuss the effects of superfluidity on the shear viscosity in a neutron
star core. Our study combines existing theoretical results for the viscosity
coefficients with data for the various superfluid energy gaps into a consistent
description. In particular, we provide a simple model for the electron
viscosity which is relevant both when the protons form a normal fluid and when
they become superconducting. This model explains in a clear way why proton
superconductivity leads to a significant strengthening of the shear viscosity.
We present our results in a form which permits the use of data for any given
modern equation of state (our final formulas are explicitly dependent on the
proton fraction). We discuss a simple description of the relevant superfluid
pairing gaps, and construct a number of models (spanning the range of current
uncertainty) which are then used to discuss the superfluid suppression of shear
viscosity. We conclude by a discussion of a number of challenges that must be
met if we are to make further progress in this area of research.


title: Challenges at the neutron star core-crust boundary

abstract: This paper has been withdrawn by the authors.


title: Crust-core coupling in rotating neutron stars

abstract:
  Motivated by their gravitational-wave driven instability, we investigate the
influence of the crust on r-mode oscillations in a neutron star. Using a
simplistic model of an elastic neutron star crust with constant shear modulus,
we carry out an analytic calculation with the main objective of deriving an
expression for the ``slippage'' between the core and the crust. Our analytic
estimates support previous numerical results, and provide useful insights into
the details of the problem.


title:
Where Are We Now, and Where Are We Going? Perspectives on Cosmic
  Abundances

abstract:
  I was asked at the end of this conference to provide a few comments on the
present status of the field of cosmic abundances, which I summarize (and extend
upon) in this contribution. A discussion of the present ``state of play'' is
given, along with some suggested directions for the future.


title: Deflection of Pulsar Signal Reveals Compact Structures in the Galaxy

abstract:
  We have detected a strong deflection of radio waves from the pulsar PSR
B0834+06 in scintillation observations. Interference between the undeflected
pulsar image and deflected subimages allows single dish interferometry of the
interstellar medium with sub-milliarcsecond resolution. We infer the presence
of scattering structure(s) similar to those that are thought to cause Extreme
Scattering Events in quasar flux monitoring programs: size ~ 0.2 AU (an angular
size of 0.1 mas) with an electron density of > 10^3 compared to the warm
ionized medium. The deflectors are nearly stationary in a scattering screen
that is thin (< 5% of the pulsar-observer distance in extent), is located 70%
of the way from the Earth to the pulsar, and has been seen consistently in
observations dating back 20 years. The pulsar scans the scattering screen at a
velocity of 110 km/s with a detection radius of 15 mas. Pulsar observations
such as these -- particularly with a new generation of low-frequency radio
telescopes with large collecting areas -- hold promise for improving
constraints on the poorly understood physical characteristics and space density
of the deflecting structures. Such observations may also prove useful in
correcting deviations the deflectors produce in high-precision timing of
millarcsecond pulsars.


title: Precursor activity in bright long BATSE gamma-Ray Bursts

abstract:
  We study a sample of bright long BATSE GRB light curves in the 200 s before
the detection of the GRB prompt emission. We find that in a sizable fraction of
cases (20 %) there is evidence of emission above the background coming from the
same direction of the GRB. This emission is characterised by a softer spectrum
with respect to the main one and contains a small fraction (0.1-1 %) of the
total event counts. The precursors have typical delays of several tens of
seconds extending (in few cases) up to 200 seconds (the limit of the
investigated period). Their spectra are typically non-thermal power-law but for
a few cases. Such long delays and the non-thermal origin of their spectra are
hard to reconcile with any model for the progenitor.


title:
Negative phase velocity of electromagnetic waves and the cosmological
  constant

abstract:
  Examining the propagation of electromagnetic plane waves with the wavevector
directed in opposition to the time-averaged Poynting vector in cosmological
spacetime with piecewise uniform metric, we show that such
negative-phase-velocity (NPV) propagation is possible in certain de Sitter
spacetimes but not in anti-de Sitter spacetimes. This difference suggests the
possibility of an optical/electromagnetic experiment to discern the
cosmological constant of a four-dimensional universe stemming from a
five-dimensional brane universe.


title: XMM-Newton detects the beginning of the X-ray decline of SN 1995N

abstract:
  We present the results of a new XMM-Newton observation of the interacting
supernova 1995N, performed on July 27, 2003. We find that the 0.2-10.0 keV flux
has dropt at a level of 1.44e-13 erg cm^-2 s^-1, about one order of magnitude
lower than that of a previous ASCA observation performed on January 1998. The
X-ray spectral analysis shows statistically significant evidence for the
presence of two distinct components, that can be modeled with emission from
optically thin, thermal plasmas at different temperatures. From these
temperatures we derive that the exponent of the ejecta density distribution is
n ~ 6.5.


title: Classical Cepheid Pulsation Models. X. The Period-Age Relation

abstract:
  We present new Period-Age (PA) and Period-Age-Color (PAC) relations for
fundamental and first overtone classical Cepheids. Current predictions rely on
homogeneous sets of evolutionary and pulsation models covering a broad range of
stellar masses and chemical compositions. We found that PA and PAC relations
present a mild dependence upon metal content. Moreover, the use of different PA
and PAC relation for fundamental and first overtone Cepheids improves the
accuracy of age estimates in the short-period (log P < 1) range (old Cepheids),
because they present smaller intrinsic dispersions. At the same time, the use
of the PAC relations improves the accuracy in the long-period (log P >= 1)
range (young Cepheids), since they account for the position of individual
objects inside the instability strip. We performed a detailed comparison
between evolutionary and pulsation ages for a sizable sample of LMC (15) and
SMC (12) clusters which host at least two Cepheids. In order to avoid deceptive
uncertainties in the photometric absolute zero-point, we adopted the
homogeneous set of B,V,I data for clusters and Cepheids collected by OGLE. We
also adopted the same reddening scale. The different age estimates agree at the
level of 20 % for LMC clusters and of 10 % for SMC clusters. We also performed
the same comparison for two Galactic clusters (NGC6067, NGC7790) and the
difference in age is smaller than 20 %. These findings support the use of PA
and PAC relations to supply accurate estimates of individual stellar ages in
the Galaxy and in external Galaxies. The main advantage of this approach is its
independence from the distance.


title: MASTER: The Mobile Astronomical System of Telescope-Robots

abstract:
  We present the first russian robot-telescope designed to make prompt
observations of gamma-ray bursts (http://observ.pereplet.ru). The telescopes
are near Moscow. The system of telescopes with prompt pointing rates connects
to the internet. The main parameters are the following: Richter-Slefogt system
telescope (355 mm, f/d=2.4); Richter-Slefogt system telescope (200mm, f/d=2.4);
Flugge system telescope (280mm, f/d=2.5); TV-camera with 20x40 degree
objective; Two CCD cameras (Pictor 416); One CCD Apogee Camera AP16E. The type
of mount is German with 8 grad/sec slew rate. MASTER images stars down to 19
magnitude in a 1 min exposure covering 6 square degrees.


title:
Numerical simulations of expanding supershells in dwarf irregular
  galaxies. II. Formation of giant HI rings

abstract:
  We perform numerical hydrodynamic modeling of various physical processes that
can form an HI ring as is observed in Holmberg I. Three energetic mechanisms
are considered: multiple supernova explosions (SNe), a hypernova explosion
associated with a gamma ray burst (GRB), and the vertical impact of a high
velocity cloud (HVC). The total released energy has an upper limit of 10^54
ergs. We find that multiple SNe are in general more effective in producing
shells that break out of the disk than a hypernova explosion of the same total
energy. As a consequence, multiple SNe form rings with a high ring-to-center
contrast K<100 in the HI column density, whereas single hypernova explosions
form rings with K<10. Only multiple SNe can reproduce both the size (diameter
\~1.7 kpc) and the ring-to-center contrast (K ~ 15-20) of the HI ring in
Hoolmberg I. High velocity clouds create HI rings that are much smaller in size
(< 0.8 kpc) and contrast (K < 4.5) than seen in Holmberg I. We construct model
position-velocity (pV) diagrams and find that they can be used to distinguish
among different HI ring formation mechanisms. The observed pV-diagrams of
Holmberg I are best reproduced by multiple SNe. We conclude that the giant HI
ring in Holmberg I is most probably formed by multiple SNe. We also find that
the appearance of the SNe-driven shell in the integrated HI image depends on
the inclination angle of the galaxy. In nearly face-on galaxies, the integrated
HI image shows a ring of roughly constant HI column density surrounding a deep
central depression, whereas in considerably inclined galaxies (i > 45 deg) the
HI image is characterized by two kidney-shaped density enhancements and a mild
central depression.


title: Massive X-ray binaries: New developments in the INTEGRAL era

abstract:
  The study of massive X-ray binaries provides important observational
diagnostics for a number of fundamental astrophysical issues, such as the
evolution of massive stars, the stellar winds of massive stars, the formation
of compact objects and accretion processes. More than three decades of study
have led to a coherent picture of their formation and evolution and some
understanding of the physical mechanisms involved. As more and more systems are
discovered, this picture grows in complexity. Over the last two years, INTEGRAL
has discovered a new population of massive X-ray binaries, characterised by
absorbed spectra, which challenges some of our previous assumptions and
guarantees that this will be a major subject of research for the near future.


title: Emergence of a filamentary structure in the fireball from GRB spectra

abstract:
  It is shown that the concept of a fireball with a definite filamentary
structure naturally emerges from the analysis of the spectra of Gamma-Ray
Bursts (GRBs). These results, made possible by the recently obtained analytic
expressions of the equitemporal surfaces in the GRB afterglow, depend crucially
on the single parameter R describing the effective area of the fireball
emitting the X- and gamma ray radiation. The X- and gamma ray components of the
afterglow radiation are shown to have a thermal spectrum in the co-moving frame
of the fireball and originate from a stable shock front described
self-consistently by the Rankine-Hugoniot equations. Precise predictions are
presented on a correlations between spectral changes and intensity variations
in the prompt radiation verifiable, e.g., by the Swift and future missions. The
highly variable optical and radio emission depends instead on the parameters of
the surrounding medium. The GRB 991216 is used as a prototype for this model.


title:
Expected neutrino signal from supernova remnant RX J1713.7-3946 and
  flavor oscillations

abstract:
  We consider the impact of oscillations on 1-200 TeV neutrinos expected from
RX J1713.7-3946. After a description of the nature of the source, we obtain a
prediction for the neutrino fluxes, based on the intense gamma ray flux first
seen by CANGAROO and recently measured by H.E.S.S. experiment. We study the
effect of 3 flavor oscillations in detail and consider the impact on the muon
flux induced by these high energy neutrinos, potentially observable by a
neutrino telescope located in the Northern hemisphere. A detector in the
Mediterranean with an effective area of 1 km^2 and unit detection efficiency
should be able to see a signal of about 10 muons per year.


title: A new inverse method for stellar population synthesis and error analysis

abstract:
  The stellar population synthesis in unresolved composite objects is a very
tricky problem. Indeed, it is a degenerate problem since many parameters affect
the observables. The stellar population synthesis issue thus deserves a deep
and rigourous analysis. In this paper we present a method of inversion which
uses as observables the intensities at each pixel of a galactic spectrum and
provides the stellar contribution to luminosity of all stars considered in a
database. The main contribution of this paper to the synthesis problem is that
it provides an analytical computation of the uncertainties accompanying a
solution. This constitutes an important improvement relative to previous
methods which do not provide such infomation except in the method described by
Pelat (1997) and Moultaka & Pelat (2000). The latter uses the equivalent widths
and intensities of stellar spectra in order to reproduce the equivalent widths
of a galactic spectrum. The novelty of this work relative to the previous one
is that the dust emission present in the IR spectra can be modeled as well as
the velocity dispersion of stars that broadens the lines of a galactic
spectrum. Tests are also performed in order to estimate the reliability of the
method and the influence on the results of an additive continuum present in a
studied spectrum, for example in the case of AGNs.


title: A Unified Model of High-Energy Astrophysical phenomena

abstract:
  I outline a unified model of high-energy astrophysics, in which the gamma
background radiation, cluster "cooling flows", gamma-ray bursts, X-ray flashes
and cosmic-ray electrons and nuclei of all energies -share a common origin. The
mechanism underlying these phenomena is the emission of relativistic
"cannonballs" by ordinary supernovae, analogous to the observed ejection of
plasmoids by quasars and microquasars. I concentrate on Cosmic Rays: the
longest-lasting conundrum in astrophysics. The distribution of Cosmic Rays in
the Galaxy, their total "luminosity", the broken power-law spectra with their
observed slopes, the position of the knee(s) and ankle(s), and the alleged
variations of composition with energy are all explained in terms of simple and
"standard" physics. The model is only lacking a satisfactory theoretical
understanding of the "cannon" that emits the cannonballs in catastrophic
episodes of accretion onto a compact object.


title: The Interaction of 3C401 with the Surrounding Intracluster Medium

abstract:
  We present an observation of the radio-galaxy 3C401 and the surrounding
intracluster medium (ICM) of its host galaxy cluster by the Chandra X-ray
Observatory. This luminous radio-galaxy is notable in that it has
characteristics intermediate between the FRI and FRII morphologies. We clearly
detect point-like emission coincident with the radio-core of 3C401, although
the spatial resolution of even Chandra is only 2kpc at the distance of 3C401
(z=0.201) and so the possibility remains that this is a dense (and rapidly
cooling) thermal gaseous core in the center of the ICM atmosphere. Strong
departures from spherical symmetry in the central 10-20kpc of the ICM clearly
suggest interaction between the ICM and the radio-lobes of 3C401. A central
X-ray bar probably results from the evacuation of two ICM cavities by the
expanding radio lobes. Beyond these central regions, the cluster possesses a
flatter profile than many clusters of comparable mass suggesting the importance
of ICM heating and entropy injection by 3C401. We detect an interesting
cross-like structure in the ICM on 100kpc scales. We speculate that this could
be a radio-galaxy induced disturbance corresponding to a time when 3C401 was
substantially more powerful. A particularly exciting possibility is that this
cross-like structure corresponds to a large scale global g-mode oscillation
excited by a past outburst of 3C401.


title: How star clusters could survive low star formation efficiencies

abstract:
  After the stars of a new, embedded star cluster have formed they blow the
remaining gas out of the cluster. Especially winds of high mass stars and
definitely the on-set of the first super novae can remove the residual gas from
a cluster. This leads to a very violent mass-loss and leaves the cluster out of
virial equilibrium. Standard models predict that the star formation efficiency
(SFE) has to be about 33 per cent for sudden (within one crossing-time of the
cluster) gas expulsion to retain some of the stars in a bound cluster. If the
efficiency is lower the stars of the cluster disperse completely. Recent
observations reveal that in strong star bursts star clusters do not form in
isolation but in complexes containing dozens and up to several hundred star
clusters (super-clusters). By carrying out numerical experiments we demonstrate
that in these environments (i.e. the deeper potential of the star cluster
complex and the merging process of the star clusters within these
super-clusters) the SFEs could be as low as 20 per cent, leaving a
gravitationally bound stellar population. We demonstrate that the merging of
the first clusters happens faster than the dissolution time therefore enabling
more stars to stay bound within the merger object. Such an object resembles the
outer Milky Way globular clusters and the faint fuzzy star clusters recently
discovered in NGC 1023.


title:
Dust in the Photospheric Environment III. A Fundamental Element in the
  Characterization of Ultracool Dwarfs

abstract:
  Recent photometry of L and T dwarfs revealed that the infrared colors show a
large variation at a given Teff and, within the framework of our Unified Cloudy
Model (UCM), this result can be interpreted as due to a variation of the
critical temperature (Tcr) which is essentially a measure of the thickness of
the dust cloud. It appears that the L/T transition takes place at around Teff =
1400K, where Tcr shows a particularly large change. Thus the L/T transition is
associated with a drastic change of the thickness of the dust cloud at around
Teff = 1400K, but the reason for this change is unknown. Once we allow Tcr to
vary at given Teff and log g, the two-color and color-magnitude diagrams can be
well explained as the effect of Teff, log g, and Tcr, but not by that of Teff
and log g alone. In general, the effects of Teff and Tcr are difficult to
discriminate on individual spectra, but this degeneracy of Teff and Tcr can be
removed to some extent by the analysis of the SED on an absolute scale. The
reanalysis of a selected sample of spectra revealed that the L-T spectral
sequence may not necessarily be a sequence of Teff, but may reflect a change of
the thickness of the dust cloud, represented by Tcr in our UCM. Also, an odd
'brightening' of the absolute J magnitudes plotted against the L-T spectral
types may also be a manifestation that the L-T spectral sequence is not a
temperature sequence, since Mbol also shows a similar 'brightening'. Then, the
'J-brightening' may not be due to any atmospheric effect and hence should not
be a problem to be solved by model atmospheres including the UCMs. Thus, almost
all the available observed data are reasonably well interpreted with the UCMs
in which the cloud thickness varies, and the problem now is how to understand
why the cloud thickness (or Tcr) changes independently of Teff and log g.


title: Emission Line Abundances of Absorption Selected Galaxies at z<0.5

abstract:
  We have obtained optical spectra of four galaxies associated with MgII QSO
absorbers at redshifts 0.10 < z < 0.45. We calculate the gas-phase oxygen
abundance of these galaxies using the empirical R23 strong line method. The
absolute B-band magnitudes of the galaxies span -20.6 < M_B < -18.3. If the
metallicities lie on the R23 upper branch (8.4 < log (O/H) + 12 < 8.9), then
the metallicities of these absorption selected galaxies span the range between
0.5--1.4 solar and would be consistent with the well-known
luminosity-metallicity relation for 0.10 < z < 0.45 emission-line galaxies.
However, such metallicities would be 0.5--1.0 dex higher than those observed in
damped Lyman alpha systems (DLAs) via absorption line measurements at similar
redshifts. Conversely, the lower R23 branch calibration yields metallicities
approximately 1/7 solar, consistent with the DLA absorption metallicities at
low redshifts. In this case, the absorption selected galaxies would lie
significantly lower than the luminosity-metallicity relation for emission-line
galaxies at z<0.5. We discuss the implications and possible solutions for each
scenario.


title:
The evolution of the galaxy B-band rest-frame morphology to z~2: new
  clues from the K20/GOODS sample

abstract:
  We present a detailed analysis of the evolution of the rest-frame B-band
morphology of K-selected galaxies with 0 < z < 2.5. This work is based on the
K20 spectroscopic sample (Ks<20) located within the Chandra Deep Field South
area, coupled with the public deep GOODS HST+ACSmulti-band optical imaging
available in that field. Thanks to the spectroscopic completeness of this
catalog reaching 94%, we can compare the morphological and spectroscopic
properties of galaxies with unprecedented detail. Our morphological analysis
includes visual inspection and automatic procedures using both parametric (e.g.
the Sersic indices treated by the GALFIT and GASPHOT packages) and
non-parametric (the Concentration, Asymmetry and clumpineSs, CAS) methods. Our
analysis classifies the K20 galaxies as: 60/300 (20%, class 1) normal
ellipticals/S0; 14/300 (4%, class 2) perturbed or peculiar ellipticals; 80/300
(27%, class 3) normal spirals; 48/300 (16%, class 4) perturbed or actively
star-forming spirals; 98/300 (33%, class 5) irregulars. The evolution of the
merging fraction is constrained up to z~2, by carefully accounting effects of
morphological k-correction: both asymmetry criterion and pair statistic show an
increasing merging fraction as a function of the redshift. We finally analyse
the redshift-dependence of the effective radii for early- and late-type
galaxies and find some mild evidence for a decrease with z of the early-type
galaxy sizes, while disks and irregulars remain constant. Altogether, this
analysis of the K20 sample indicates the large predominance of spirals and
irregulars at 0.5<z<1.5 in K-band selected samples at even moderate depths.


title: Evolution from AGB to planetary nebula in the MSX survey

abstract:
  We investigate the evolution of oxygen- and carbon-rich AGB stars, post-AGB
objects, and planetary nebulae using data collected mainly from the MSX
catalogue. Magnitudes and colour indices are compared with those calculated
from a grid of synthetic spectra that describe the post-AGB evolution beginning
at the onset of the superwind. We find that carbon stars and OH/IR objects form
two distinct sequences in the (K-[8.3])x([8.3]-[14.7]) MSX colour diagram.
OH/IR objects are distributed in two groups: the bluest ones are crowded near
[14.7]-[21.3]=1 and [8.3]-[14.7]=2, and a second, redder group is spread over a
large area in the diagram, where post-AGB objects and planetary nebulae are
also found. High mass-loss rate OH/IR objects, post-AGB stars, and planetary
nebulae share the same region in the (K-[8.3])x([8.3]-[14.7]) and
[14.7]-[21.3]x([8.3]-[14.7]) colour-colour diagrams. This region in the diagram
is clearly separated from a bluer one where most OH/IR stars are found. We use
a grid of models of post-AGB evolution, which are compared with the data. The
gap in the colour-colour diagrams is interpreted as the result of the rapid
trajectory in the diagram of the stars that have just left the AGB.


title: Radio--X-ray Correlation and the "Quiescent State" of Black Hole Sources

abstract:
  Recently a correlation between the radio and X-ray luminosities is found,
$L_{\rm R}\propto L_{\rm X}^{0.7}$, in black hole sources including black hole
candidates in our galaxy and active galactic nuclei. We first show that the
correlation can be understood in the context of an accretion-jet model
developed for explaining the spectral and timing properties of XTE J1118+480.
More importantly, we show that when the X-ray luminosity is below a critical
value, $\la (10^{-5}$--$10^{-6}) L_{\rm Edd}$, if the jet persists, the
correlation should turn and become steeper, $L_{\rm R}\propto L_{\rm
X}^{1.23}$, and the X-ray radiation of the system should be dominated by the
emission from the jet, rather than by the accretion flow. Possible
observational evidence for our predictions is presented and future observations
to further test our predictions are proposed.


title:
Hydrodynamic simulations of molecular outflows driven by slow-precessing
  protostellar jets

abstract:
  We present hydrodynamic simulations of molecular outflows driven by jets with
a long period of precession, motivated by observations of arc-like features and
S-symmetry in outflows associated with young stars. We simulate images of not
only H2 vibrational and CO rotational emission lines, but also of atomic
emission. The density cross section displays a jaw-like cavity, independent of
precession rate. In molecular hydrogen, however, we find ordered chains of bow
shocks and meandering streamers which contrast with the chaotic structure
produced by jets in rapid precession. A feature particularly dominant in atomic
emission is a stagnant point in the flow that remains near the inlet and alters
shape and brightness as the jet skims by. Under the present conditions, slow
jet precession yields a relatively high fraction of mass accelerated to high
speeds, as also attested to in simulated CO line profiles. Many outflow
structures, characterised by HH222 (continuous ribbon), HH240 (asymmetric
chains of bow shocks) and RNO43N (protruding cavities), are probably related to
the slow precession model.


title:
The Evolution of Early-type Red Galaxies with the GEMS Survey:
  Luminosity-size and Stellar Mass-size Relations Since z=1

abstract:
  We combine HST/ACS imaging from the GEMS survey with redshifts and rest-frame
quantities from COMBO-17 to study the evolution of morphologically early-type
galaxies with red colors since z=1. We use a new large sample of 728 galaxies
with centrally-concentrated radial profiles (Sersic n>2.5) and rest-frame U-V
colors on the red sequence. By appropriate comparison with the local relations
from SDSS, we find that the luminosity-size (L-R) and stellar mass-size (M-R)
relations evolve in a manner that is consistent with the passive aging of
ancient stars. By itself, this result is consistent with a completely passive
evolution of the red early-type galaxy population. If instead, as demonstrated
by a number of recent surveys, the early-type galaxy population builds up in
mass by a factor of 2 since z=1, our results imply that new additions to the
early-type galaxy population follow similar L-R and M-R correlations, compared
to the older subset of early-type galaxies. Adding early-type galaxies to the
red sequence through disk fading appears to be consistent with the data.
Through comparison with models, the role of dissipationless merging is limited
to <1 major merger on average since z=1 for the most massive galaxies.
Predictions from models of gas-rich mergers are not yet mature enough to allow
a detailed comparison to our observations. We find tentative evidence that the
amount of luminosity evolution depends on galaxy stellar mass, such that the
least massive galaxies show stronger luminosity evolution compared to more
massive early types. This could reflect a different origin of low-mass
early-type galaxies and/or younger stellar populations; the present data is
insufficient to discriminate between these possibilities. (abridged)


title: Non-Gaussianity in braneworld and tachyon inflation

abstract:
  We calculate the bispectrum of single-field braneworld inflation, triggered
by either an ordinary scalar field or a cosmological tachyon, by means of a
gradient expansion of large-scale non-linear perturbations coupled to
stochastic dynamics. The resulting effect is identical to that for single-field
4D standard inflation, the non-linearity parameter being proportional to the
scalar spectral index in the limit of collapsing momentum. If the slow-roll
approximation is assumed, braneworld and tachyon non-Gaussianities are
subdominant with respect to the post-inflationary contribution. However, bulk
physics may considerably strengthen the non-linear signatures. These features
do not change significantly when considered in a non-commutative framework.


title:
The connection between star formation and stellar mass: Specific star
  formation rates to redshift one

abstract:
  We investigate the contribution of star formation to the growth of stellar
mass in galaxies over the redshift range 0.5 < z < 1.1 by studying the redshift
evolution of the specific star formation rate (SSFR), defined as the star
formation rate per unit stellar mass. We use an I-band selected sample of 6180
field galaxies from the Munich Near-Infrared Cluster Survey (MUNICS) with
spectroscopically calibrated photometric redshifts. The SSFR decreases with
stellar mass at all redshifts. The low SSFRs of massive galaxies indicates that
star formation does not significantly change their stellar mass over this
redshift range: The majority of massive galaxies have assembled the bulk of
their mass before redshift unity. Furthermore, these highest mass galaxies
contain the oldest stellar populations at all redshifts. The line of maximum
SSFR runs parallel to lines of constant star formation rate. With increasing
redshift, the maximum SFR is generally increasing for all stellar masses, from
SFR ~ 5 M_sun/yr at z = 0.5 to SFR ~ 10 M_sun/yr at z = 1.1. We also show that
the large SSFRs of low-mass galaxies cannot be sustained over extended periods
of time. Finally, our results do not require a substantial contribution of
merging to the growth of stellar mass in massive galaxies over the redshift
range probed. We note that highly obscured galaxies which remain undetected in
our sample do not affect these findings for the bulk of the field galaxy
population.


title: Cosmic Star Formation History and its Dependence on Galaxy Stellar Mass

abstract:
  We examine the cosmic star formation rate (SFR) and its dependence on galaxy
stellar mass over the redshift range 0.8 < z < 2 using data from the Gemini
Deep Deep Survey (GDDS). The SFR in the most massive galaxies (M > 10^{10.8}
M_sun) was six times higher at z = 2 than it is today. It drops steeply from z
= 2, reaching the present day value at z ~ 1. In contrast, the SFR density of
intermediate mass galaxies (10^{10.2} < M < 10^{10.8} M_sun) declines more
slowly and may peak or plateau at z ~ 1.5. We use the characteristic growth
time t_SFR = rho_M / rho_SFR to provide evidence of an associated transition in
massive galaxies from a burst to a quiescent star formation mode at z ~ 2.
Intermediate mass systems transit from burst to quiescent mode at z ~ 1, while
the lowest mass objects undergo bursts throughout our redshift range. Our
results show unambiguously that the formation era for galaxies was extended and
proceeded from high to low mass systems. The most massive galaxies formed most
of their stars in the first ~3 Gyr of cosmic history. Intermediate mass objects
continued to form their dominant stellar mass for an additional ~2 Gyr, while
the lowest mass systems have been forming over the whole cosmic epoch spanned
by the GDDS. This view of galaxy formation clearly supports `downsizing' in the
SFR where the most massive galaxies form first and galaxy formation proceeds
from larger to smaller mass scales.


title: On the Incidence and Kinematics of Strong Mg II Absorbers

abstract:
  We present the results of two investigations into the nature of strong (rest
equivalent width > 1.0 Ang) Mg II absorption systems at high redshift. The
first line of questioning examines the complete SDSS- DR3 set of quasar spectra
to determine the evolution of the incidence of strong Mg II absorption. The
redshift evolution of the comoving line-of-sight number density, l(x), is
characterized by a roughly constant value at z > 0.8, indicating that the
product of the number density and gas cross-section of halos hosting strong Mg
II is unevolving at these redshifts. At z < 0.8 there is a decline in l(x),
which we interpret as a decrease in the gas cross-section to strong Mg II
absorption and therefore a decline in the physical processes relevant to such
absorption. This evolution roughly tracks the global evolution of the SFR
density. The decrease of l(x) is more pronounced for larger equivalent width
systems. We also present the results of a search for strong Mg II absorption in
91 high resolution quasar spectra, which allow us to investigate the kinematics
of such systems. These systems are characterized by the presence of numerous
components spread over a ~200 km/s velocity width and the presence of more
highly ionized species, which display kinematic profiles similar to the
corresponding Mg II absorption. We consider these results in light of two
competing theories to explain strong Mg II absorption: post-starburst,
SN-driven galactic winds and accreting gas in the halos of massive galaxies.
The later model is disfavored by the absence of evolution in l(x) at z > 1. We
argue that the strong Mg II phenomenon primarily arises from feedback processes
in relatively low mass galactic halos related to star formation.


title: On the Mass-to-Light Ratio of Large Scale Structure

abstract:
  We examine the dependence of the mass-to-light (M/L) ratio of large-scale
structure on cosmological parameters, in models that are constrained to match
observations of the projected galaxy correlation function w(rp). For a sequence
of cosmological models with a fixed P(k) shape and increasing normalization
\sig8, we find parameters of the galaxy halo occupation distribution (HOD) that
reproduce SDSS measurements of w(rp) as a function of luminosity. Using these
HOD models we calculate mean M/L ratios as a function of halo mass and populate
halos of N-body simulations to compute M/L in larger scale environments,
including cluster infall regions. For all cosmological models, the M/L ratio in
high mass halos or high density regions is approximately independent of halo
mass or smoothing scale. However, the "plateau" value of M/L depends on \sig8
as well as \Omega_m, and it represents the universal mass-to-light ratio <M/L>
only for models in which the galaxy correlation function is approximately
unbiased, i.e., with \sig8 ~ \sig8_gal. Our results for cluster mass halos
follow the trend M/L = 577(\Omega_m/0.3)(\sig8/0.9)^{1.7} h Msun/Lsun. Combined
with Carlberg et al.'s (1996) mean M/L ratio of CNOC galaxy clusters, this
relation implies (\sig8/0.9)(\Omega_m/0.3)^{0.6} = 0.75 +/- 0.06. M/L ratios of
clusters from the SDSS and CAIRNS surveys yield similar results. This
constraint is inconsistent with parameter values \Omega_m ~ 0.3, \sig8 ~ 0.9
favored by recent joint analyses of CMB measurements and other large-scale
structure data. We discuss possible resolutions, none of which seems entirely
satisfactory. Appendices present an improved formula for halo bias factors and
an improved analytic technique for calculating the galaxy correlation function
from a given cosmological model and HOD. (Abridged)


title:
Supernovae in Helium Star--Compact Object Binaries: A Possible Gamma-ray
  Burst Mechanism

abstract:
  Helium star--compact object binaries, and helium star--neutron star binaries
in particular, are widely believed to be the progenitors of the observed double
neutron star systems. In these, the second neutron star is presumed to be the
compact remnant of the helium star supernova. Here, the observational
implications of such a supernova are discussed, and in particular are explored
as a candidate gamma-ray burst mechanism. In this scenario the supernova
results in a transient period of rapid accretion onto the compact object,
extracting via magnetic torques its rotational energy at highly super-Eddington
luminosities in the form of a narrowly beamed, strongly electromagnetically
dominated jet. Compton scattering of supernova photons advected within the
ejecta, and photons originating at shocks driven into the ejecta by the jet,
will cool the jet and can produce the observed prompt emission characteristics,
including the peak--inferred isotropic energy relation, X-ray flash
characteristics, subpulse light curves, energy dependent time lags and subpulse
broadening, and late time spectral softening. The duration of the burst is
limited by the rate of Compton cooling of the jet, eventually creating an
optically thick, moderately relativistically expanding fireball which can
produce the afterglow emission. If the black hole or neutron star stays bound
to a compact remnant, late term light curve variability may be observed as in
SN 2003dh.


title: The strange case of a sub-DLA with very little HI

abstract:
  We report a deep search for HI 21cm emission from the $z= 0.00632$ sub-DLA
toward PG1216+069 with the Giant Metrewave Radio Telescope. No emission was
detected and our $5\sigma$ upper limit on the mass of any associated galaxy is
$M_{\rm HI} \lesssim 10^7 M_\odot$, nearly 3 orders of magnitude less than
M$_{\rm HI}^\star$. The $z \sim 0.006$ absorber is thus the most extreme known
deviation from the standard paradigm in which high column density quasar
absorption lines arise in the disks of gas-rich galaxies.


title:
Identification of an Extended Accretion Disk Corona in the Hercules X-1
  Low State: Moderate Optical Depth, Precise Density Determination, and
  Verification of CNO Abundances

abstract:
  We identify an accretion disk atmosphere and corona from the high resolution
X-ray spectrum of Hercules X-1, and we determine its detailed physical
properties. More than two dozen recombination emission lines (from Fe XXVI at
1.78 A to N VI at 29.08 A) and Fe K-alpha, K-beta fluorescence lines were
detected in a 50 ks observation with the Chandra High-Energy Transmission
Grating Spectrometer (HETGS). They allow us to measure the density,
temperature, spatial distribution, elemental composition, and kinematics of the
plasma. We exclude HZ Her as the source of the recombination emission. We
compare accretion disk model atmospheres with the observed spectrum in order to
constrain the stratification of density and ionization, disk atmosphere area,
elemental composition, and energetics. The atmospheric spectrum observed during
the low state is photoionized by the main-on X-ray continuum, indicating that
the disk is observed edge-on during the low state. We infer the mean number of
scatterings N of Ly-alpha and Ly-beta line photons from H-like ions. We derive
N < 69 for O VIII Ly_alpha_1, which rules out the presence of a mechanism
modeled by Sako (2003) to enhance N VII emission via a line overlap with O
VIII. The line optical depth diagnostics are consistent with a flattened
atmosphere. Our spectral analysis, the disk atmosphere model, and the presence
of intense N VII and N VI lines (plus N V in the UV), confirm the
over-abundance of nitrogen relative to other metals, which was shown to be
indicative of CNO cycle processing in a massive progenitor.


title: Magnetised plasma turbulence in clusters of galaxies

abstract:
  Cluster plasmas are magnetised already at very low magnetic field strength.
Low collisionality implies that conservation of the first adiabatic invariant
results in an anisotropic viscous stress (Braginskii viscosity) or,
equivalently, anisotropic plasma pressure. This triggers firehose and mirror
instabilities, which have growth rates proportional to the wavenumber down to
scales of the order of ion Larmor radius. This means that MHD equations with
Braginskii viscosity are not well posed and fully kinetic description is
necessary. In this paper, we review the basic picture of small-scale dynamo in
the cluster plasma and attempt to reconcile it with the existence of plasma
instabilities at collisionless scales.


title:
The Wide Field Imager Lyman-Alpha Search (WFILAS) for Galaxies at
  Redshift ~5.7: I. A Spatially Compact Lyman-alpha Emitting Galaxy at Redshift
  5.721

abstract:
  We report the spectroscopic confirmation of a compact \lya emitting galaxy at
$z=5.721$. A FORS2 spectrum of the source shows a strong asymmetric line with a
flux of 5$\times10^{-17}$ erg s$^{-1}$ cm$^{-2}$, making it one of the
brightest \lya emitting galaxies at this redshift, and a line-of-sight velocity
dispersion of 400 km s$^{-1}$. We also have a tentative detection of a second,
narrower component that is redshifted by 400 km s$^{-1}$ with respect to the
main peak. A FORS2 image shows that the source is compact, with a FWHM of
0\farcs5, which corresponds to 3.2 kpc at this redshift. This source is a
brighter example of \object{J1236.8+6215} \citep{Dawson02}, another \lya\
emitting galaxy at $z\sim5.2$.


title: Making Carbon in Stars

abstract:
  The triple alpha process plays an important role in the production of 12C in
stars. Its rate is known with an accuracy of about 12%. We examine the
corresponding uncertainties introduced in the description of pre-supernova
stars, of nucleosynthesis in a core-collapse SN explosion, and of the
production of 12C during the third dredge-up in asymptotic giant branch (AGB)
stars. For the AGB case we consider also the effects of uncertainties in the
14N(p,gamma)15O rate. We conclude that the present accuracy of the triplr alpha
rate is inadequate and describe new experiments that will lead to a more
accurate value.


title: R-modes of a neutron star with a magnetic dipole field

abstract:
  We study $r$-modes of a rotating magnetized neutron star, assuming a magnetic
dipole field whose axis is aligned with the axis of rotation. We approach the
problem by applying a singular perturbation theory to the oscillations of
rotating stars. In this treatment, we divide the star into a thin surface
magnetic layer and a non-magnetic core. We integrate linearized ideal MHD
equations in the surface magnetic layer and non-magnetic oscillation equations
in the core, and match the two integrations at the interface to obtain a
complete solution. For a polytropic neutron star model of mass $M=1.4M_\odot$
and radius $R=10^6$cm, the magnetic dipole field becomes effective on the modal
properties of the $r$-modes only when the field strength $B_S$ is much greater
than $10^{14}$G. We also find that the damping effects caused by very short
magnetic perturbations in the surface layer are not important for the $r$-mode
instability of rapidly rotating neutron stars if the field strength $B_S$ is
smaller than $10^{12}$G.


title:
Molecular dynamics simulation of gaseous atomic hydrogen interactions
  with hydrocarbon grains

abstract:
  Semi-empirical molecular dynamics is used to simulate several gaseous atomic
hydrogen interactions with hydrocarbon grains in space: recoil, adsorption,
diffusion, chemisorption and recombination into molecular hydrogen. Their
probabilities are determined by multiple numerical experiments, as a function
of initial velocity of gas atoms. The equilibrium hydrogen coverage of free
grains is then derived. These data can be used in calculations of material and
energy balance as well as rates of hydrogen recombination on grains. The role
of grain temperature is also considered.


title: Strong gravitational lensing by braneworld black holes

abstract:
  In this paper, we use the strong field limit approach to investigate the
gravitational lensing properties of braneworld black holes. Applying this
method to the supermassive black hole at the centre of our galaxy, the lensing
observables for some candidate braneworld black hole metrics are compared with
those for the standard Schwarzschild case. It is found that braneworld black
holes could have significantly different observational signatures to the
Schwarzschild black hole.


title: Improvements for group delay fringe tracking

abstract:
  Group delay fringe tracking using spectrally-dispersed fringes is suitable
for stabilising the optical path difference in ground-based astronomical
optical interferometers in low light situations. We discuss the performance of
group delay tracking algorithms when the effects of atmospheric dispersion,
high-frequency atmospheric temporal phase variations, non-ideal path
modulation, non-ideal spectral sampling, and the detection artifacts introduced
by electron-multiplying CCDs (EMCCDs) are taken into account, and we present
ways in which the tracking capability can be optimised in the presence of these
effects.


title: Photometric Observation and Apsidal motion Study of V1143 Cyg

abstract:
  Photometric observations of the eccentric eclipsing binary V1143 Cygni were
performed during the August-September 2000 and July 2002, in B and V bands of
the Johnson system. The analysis on both light curves was done separately using
the 1998 version of Wilson's LC code. In order to find a new observed rate of
apsidal motion, we followed the procedure described by Guinan and Maloney
(1985). A new observed rate of apsidal motion of 3.72 degrees/100yr was
computed which is close to the one reported earlier by Khaliullin (1983),
Gimenez and Margrave (1985), and Burns et al.(1996).