title:
The Las Campanas/AAT Rich Cluster Survey III: Spectroscopic Studies of
  X-ray Bright Galaxy Clusters at z~0.1

abstract:
  [abridged] We present the analysis of the spectroscopic and photometric
catalogues of 11 X-ray luminous clusters at z=0.07-0.16 from the Las Campanas /
Anglo-Australian Telescope Rich Cluster Survey. Our spectroscopic dataset
consists of over 1600 galaxy cluster members, of which two thirds are outside
r_200. We assign cluster membership using a detailed mass model and expand on
our previous work on the cluster colour-magnitude relation where membership was
inferred statistically. We confirm that the modal colours of galaxies on the
colour magnitude relation become progressively bluer with increasing radius and
decreasing local galaxy density. Interpreted as an age effect, we hypothesize
that these trends in galaxy colour should be reflected in mean Hdelta
equivalent width. We confirm that passive galaxies in the cluster increase in
Hdelta line strength as dHdelta / d r_p = 0.35 +/- 0.06. A variation of star
formation rate, as measured by [OII], with increasing local density of the
environment is discernible and is shown to be in broad agreement with previous
studies from 2dFGRS and SDSS. We find that clusters at z~0.1 are less active
than their higher redshift analogues. We also investigate unusual populations
of blue and very red nonstarforming galaxies and we suggest that the former are
likely to be the progenitors of galaxies which will lie on the colour-magnitude
relation, while the colours of the latter possibly reflect dust reddening. The
cluster galaxies at large radii consist of both backsplash ones and those that
are infalling to the cluster for the first time. We make a comparison to the
field population at z~0.1 and examine broad differences between the two
populations. Individually, the clusters show significant variation in their
galaxy populations which reflects their recent infall histories.


title: Terrestrial Exoplanet Light Curves

abstract:
  The phase or orbital light curves of extrasolar terrestrial planets in
reflected or emitted light will contain information about their atmospheres and
surfaces complementary to data obtained by other techniques such as
spectrosopy. We show calculated light curves at optical and thermal infrared
wavelengths for a variety of Earth-like and Earth-unlike planets. We also show
that large satellites of Earth-sized planets are detectable, but may cause
aliasing effects if the lightcurve is insufficiently sampled.


title: HETE-2 Localization and Observations of the Gamma-Ray Burst GRB 020813

abstract:
  A bright, long gamma-ray burst (GRB) was detected and localized by the
instruments on board the High Energy Transient Explorer 2 satellite (HETE-2) at
02:44:19.17 UTC (9859.17 s UT) on 2002 August 13. The location was reported to
the GRB Coordinates Network (GCN) about 4 min after the burst. In the prompt
emission, the burst had a duration of approximately 125 s, and more than four
peaks. We analyzed the time-resolved 2-400 keV energy spectra of the prompt
emission of GRB 020813 using the Wide Field X-Ray Monitor (WXM) and the French
Gamma Telescope (FREGATE) in detail. We found that the early part of the burst
(17-52 s after the burst trigger) shows a depletion of low-energy photons below
about 50 keV. It is difficult to explain the depletion with by either
synchrotron self-absorption or Comptonization. One possibility is that the
low-energy depletion may be understood as a mixture of ``jitter'' radiation the
usual synchrotron radiation component.


title: Island Universes

abstract: Conference Summary


title:
The thermodynamics of collapsing molecular cloud cores using smoothed
  particle hydrodynamics with radiative transfer

abstract:
  We present the results of a series of calculations studying the collapse of
molecular cloud cores performed using a three-dimensional smoothed particle
hydr odynamics code with radiative transfer in the flux-limited diffusion
approximation. The opacities and specific heat capacities are identical for
each calculation. However, we find that the temperature evolution during the
simulations varies significantly when starting from different initial
conditions. Even spherically-symmetric clouds with different initial densities
show markedly different development. We conclude that simple barotropic
equations of state like those used in some previous calculations provide at
best a crude approximation to the thermal behaviour of the gas. Radiative
transfer is necessary to obtain accurate temperatures.


title:
The very low-mass population of the Corona Australis and Chamaeleon II
  star forming regions

abstract:
  We present the results of a deep optical survey in the Corona Australis and
Chamaeleon II star forming regions. Our optical photometry is combined with
available near- and mid-infrared photometry to identify very low-mass candidate
members in these dark clouds. In our Chamaeleon II field, only one object
exhibits clear H-alpha emission, but the discrepancy between its optical and
near-infrared colours suggests that it might be a foreground star. We also
identify two objects without H-alpha emission that could be planetary mass
members of Chamaeleon II. In Corona Australis, we find ten stars and three
brown dwarf candidates in the Coronet cluster. Five of our new members are
identified with ISOCAM sources. Only two of them have a mid-infrared excess,
indicating the presence of an accretion disk. On the other hand, one brown
dwarf candidate has a faint close companion, seen only in our deepest I-band
image. For many of the candidates in both clouds, membership could not be
inferred from their H-alpha emission or near-infrared colours; these objects
need spectroscopic confirmation of their status.


title:
Log-parabolic spectra and particle acceleration in blazars. III: SSC
  emission in the TeV band from Mkn 501

abstract:
  Curved broad-band spectral distributions of non-thermal sources like blazars
are described well by a log-parabolic (LP) law where the second degree term
measures the curvature. LP energy spectra can be obtained for relativistic
electrons by means of a statistical acceleration mechanism whose probability of
acceleration depends on energy. In this paper we compute the spectra radiated
by an electron population via synchrotron (S) and Synchro-Self Compton(SSC)
processes to derive the relations between the LP parameters. These spectra were
obtained by means of an accurate numerical code. We found that the ratio
between the curvature parameters of the S spectrum to that of the electrons is
equal to about 0.2 instead of 0.25, the value foreseen in the delta
approximation. Inverse Compton spectra are also intrinsically curved and can be
approximated by a log-parabola only in limited ranges. The curvature parameter,
estimated around the SED peak, may vary from a lower value than that of the S
spectrum up to that of emitting electrons depending on whether the scattering
is in the Thomson or in the Klein-Nishina regime. We applied this analysis to
computing the SSC emission from the BL Lac object Mkn 501 during the large
flare of April 1997. We fit simultaneous BeppoSAX and CAT data and reproduced
intensities and spectral curvatures of both components with good accuracy. The
large curvature observed in the TeV range was found to be mainly intrinsic, and
therefore did not require a large pair production absorption against the
extragalactic background. We regard this finding as an indication that the
Universe is more transparent at these energies than previously assumed by
several models found in the literature. This conclusion is supported by recent
detection of two relatively high redshift blazars with H.E.S.S.


title: Sky coverage of orbital detectors. Analytical approach

abstract:
  Orbital detectors without pointing capability have to keep their field of
view axis laying on their orbital plane, to observe the largest sky fraction. A
general approach to estimate the exposure of each sky element for such
detectors is a valuable tool in the R&D phase of a project, when the detector
characteristics are still to be fixed. An analytical method to estimate the sky
exposure is developed, which makes only few very reasonable approximations. The
formulae obtained with this method are used to compute the histogram of the sky
exposure of a hypothetical gamma-ray detector installed on the ISS. The C++
code used in this example is freely available on the
https://github.com/dcasadei/SkyCoverage web page.


title: Halo Shapes and their Relation to Environment

abstract:
  Using high resolution DM simulations we study the shape of dark matter halos.
Halos become more spherical with decreasing mass. This trend is even more
pronounced for the inner part of the halo. Angular momentum and shape are
correlated. The angular momenta of neighboring halos are correlated.


title:
Probing the physical properties of the NGC 5548 Broad Line Region using
  Balmer lines

abstract:
  We investigate the physical characteristics of the Broad Line Region (BLR) of
NGC 5548 using the Boltzmann plot (BP) method, that we applied on the Balmer
lines observed from 1996 to 2004. We find that variability earlier detected in
the lines, is also present in the temperature parameter A, obtained from the BP
method. Using the BP temperature parameter A to calculate temperature, we find
that the average temperature for the considered period was T$\approx$ 10000 K,
and that varies from 5000 K (in 2002) to 15000 K (in 1998). This variation
correlates with the AGN-component of the optical continuum flux (r=0.85) and
may indicate the existence of an accretion disc in the BLR of NGC 5548.


title:
The shower size parameter as estimator of extensive air shower energy in
  fluorescence telescopes

abstract:
  The fluorescence technique has been successfully used to detect ultrahigh
energy cosmic rays by indirect measurements. The underlying idea is that the
number of charged particles in the atmospheric shower, i.e, its longitudinal
profile, can be extracted from the amount of emitted nitrogen fluorescence
light. However the influence of shower fluctuations and the very possible
presence of different nuclear species in the primary cosmic ray spectrum makes
the estimate of the shower energy from the fluorescence data analysis a
difficult task. We investigate the potential of shower size at maximum depth as
estimator of shower energy. The detection of the fluorescence light is
simulated in detail and the reconstruction biases are carefully analyzed. We
extend our calculations to both HiRes and EUSO experiments. This approach has
shown some advantages to the reconstruction of the energy when compared to the
standard analysis procedure.


title:
A detailed spectral and morphological study of the gamma-ray supernova
  remnant RX J1713.7-3946 with H.E.S.S

abstract:
  We present results from deep observations of the Galactic shell-type
supernova remnant (SNR) RX J1713.7-3946 (also known as G347.3-0.5) conducted
with the complete H.E.S.S. array in 2004. Detailed morphological and spatially
resolved spectral studies reveal the very-high-energy (VHE -- Energies E > 100
GeV) gamma-ray aspects of this object with unprecedented precision. Since this
is the first in-depth analysis of an extended VHE gamma-ray source, we present
a thorough discussion of our methodology and investigations of possible sources
of systematic errors. Gamma rays are detected throughout the whole SNR. The
emission is found to resemble a shell structure with increased fluxes from the
western and northwestern parts. The differential gamma-ray spectrum of the
whole SNR is measured over more than two orders of magnitude, from 190 GeV to
40 TeV, and is rather hard with indications for a deviation from a pure power
law at high energies. Spectra have also been determined for spatially separated
regions of RX J1713.7-3946. The flux values vary by more than a factor of two,
but no significant change in spectral shape is found. There is a striking
correlation between the X-ray and the gamma-ray image. Radial profiles in both
wavelength regimes reveal the same shape almost everywhere in the region of the
SNR. The VHE gamma-ray emission of RX J1713.7-3946 is phenomenologically
discussed for two scenarios, one where the gamma rays are produced by VHE
electrons via Inverse Compton scattering and one where the gamma rays are due
to neutral pion decay from proton-proton interactions. In conjunction with
multi-wavelength considerations, the latter case is favoured. However, no
decisive conclusions can yet be drawn regarding the parent particle population
dominantly responsible for the gamma-ray emission from RX J1713.7-3946.


title: A Massive Planet to the Young Disc Star HD 81040

abstract:
  We report the discovery of a massive planetary companion orbiting the young
disc star HD 81040. Based on five years of precise radial-velocity measurements
with the HIRES and ELODIE spectrographs, we derive a spectroscopic orbit with a
period $P =1001.0$ days and eccentricity $e = 0.53$. The inferred minimum mass
for the companion of $m_2\sin i = 6.86$ M$_\mathrm{Jup}$ places it in the
high-mass tail of the extrasolar planet mass distribution. The radial-velocity
residuals exhibit a scatter significantly larger than the typical internal
measurement precision of the instruments. Based on an analysis of the Ca II H
and K line cores, this is interpreted as an activity-induced phenomenon.
However, we find no evidence for the period and magnitude of the
radial-velocity variations to be caused by stellar surface activity. The
observed orbital motion of HD 81040 is thus best explained with the presence of
a massive giant planet companion.


title:
Detection of the effect of cosmological large-scale structure on the
  orientation of galaxies

abstract:
  Galaxies are not distributed randomly throughout space but are instead
arranged in an intricate "cosmic web" of filaments and walls surrounding
bubble-like voids. There is still no compelling observational evidence of a
link between the structure of the cosmic web and how galaxies form within it.
However, such a connection is expected on the basis of our understanding of the
origin of galaxy angular momentum: disk galaxies should be highly inclined
relative to the plane defined by the large-scale structure surrounding them.
Using the two largest galaxy redshift surveys currently in existence (2dFGRS
and SDSS) we show at the 99.7% confident level that these alignments do indeed
exist: spiral galaxies located on the shells of the largest cosmic voids have
rotation axes that lie preferentially on the void surface.


title: Iron depletion in the hot bubbles in planetary nebulae

abstract:
  We have searched for the emission from \fex and \fexiv that is expected from
the gas emitting in diffuse X-rays in \bd, NGC 6543, NGC 7009, and NGC 7027.
Neither line was detected in any object. Models that fit the X-ray spectra of
these objects indicate that the \fex emission should be below our detection
thresholds, but the predicted \fexiv emission exceeds our observed upper limits
(one sigma) by factors of at least 3.5 to 12. The best explanation for the
absence of \fexiv is that the X-ray plasma is depleted in iron. In principle,
this result provides a clear chemical signature that may be used to determine
the origin of the X-ray gas in either the nebular gas or the stellar wind. At
present, though various lines of evidence appear to favour a nebular origin,
the lack of atmospheric and nebular iron abundances in the objects studied here
precludes a definitive conclusion.


title:
Discovery of a very extended X-ray halo around a quiescent spiral galaxy
  - the "missing link" of galaxy formation

abstract:
  Hot gaseous haloes surrounding galaxies and extending well beyond the
distribution of stars are a ubiquitous prediction of galaxy formation
scenarios. The haloes are believed to consist of gravitationally trapped gas
with a temperature of millions of Kelvin. The existence of such hot haloes
around massive elliptical galaxies has been established through their X-ray
emission. While gas out-flowing from starburst spiral galaxies has been
detected, searches for hot haloes around normal, quiescent spiral galaxies have
so far failed, casting doubts on the fundamental physics in galaxy formation
models. Here we present the first detection of a hot, large-scale gaseous halo
surrounding a normal, quiescent spiral galaxy, NGC 5746, alleviating a
long-standing problem for galaxy formation models. In contrast to starburst
galaxies, where the X-ray halo can be powered by the supernova energy, there is
no such power source in NGC 5746. The only compelling explanation is that we
are here witnessing a galaxy forming from gradually in-flowing hot and dilute
halo gas.


title: The Transparency of Solar Coronal Active Regions

abstract:
  Resonance scattering has often been invoked to explain the disagreement
between the observed and predicted line ratios of Fe XVII 15.01 A to Fe XVII
15.26 A (the ``3C/3D'' ratio). In this process photons of 15.01, with its much
higher oscillator strength, are preferentially scattered out of the line of
sight, thus reducing the observed line ratio. Recent laboratory measurements,
however, have found significant inner-shell Fe XVI lines at 15.21 and 15.26
Angstroms, suggesting that the observed 3C/3D ratio results from blending.
Given our new understanding of the fundamental spectroscopy, we have
re-examined the original solar spectra, identifying the Fe XVI 15.21 line and
measuring its flux to account for the contribution of Fe XVI to the 15.26 flux.
Deblending brings the 3C/3D ratio into good agreement with the experimental
ratio; hence, we find no need to invoke resonance scattering. Low opacity in Fe
XVII 15.01 also implies low opacity for Fe XV 284.2, ruling out resonance
scattering as the cause of the fuzziness of TRACE and SOHO EIT 284-Angstrom
images. The images must, instead, be unresolved due to the large number of
structures at this temperature. Insignificant resonance scattering implies that
future instruments with higher spatial resolution could resolve the active
region plasma into its component loop structures.


title:
Reviving Dead Zones in Accretion Disks by Rossby Vortices at their
  Boundaries

abstract:
  Models of the accretion disks of Young Stellar Objects show that they should
not be ionized at a few AU from the star, and thus not subject to the MHD
turbulence believed to cause accretion. This has been suggested to create a
'Dead Zone' where accretion remains unexplained. Here we show that the
existence of the Dead Zone self-consistently creates a density profile
favorable to the Rossby Wave Instability of Lovelace et al. (1999). This
instability will create and sustain Rossby vortices in the disk which could
lead to enhanced planet formation.


title: Software design for panoramic astronomical pipeline processing

abstract:
  We describe the software requirement and design specifications for all-sky
panoramic astronomical pipelines. The described software aims to meet the
specific needs of super-wide angle optics, and includes cosmic-ray hit
rejection, image compression, star recognition, sky opacity analysis, transient
detection and a web server allowing access to real-time and archived data. The
presented software is being regularly used for the pipeline processing of 11
all-sky cameras located in some of the world's premier observatories. We
encourage all-sky camera operators to use our software and/or our hosting
services and become part of the global Night Sky Live network.


title: A Cusp Slope -- Central Anisotropy Theorem

abstract:
  For a wide class of self-gravitating systems, we show that if the density is
cusped like 1/r^{gamma} near the center, then the limiting value of the
anisotropy parameter beta = 1 - <v_T^2>/(2<v_r^2>) at the center may not be
greater than (gamma/2). Here, <v_r^2> and <v_T^2> are the radial and tangential
velocity second moments. This follows from the non-negativity of the phase
space density. We compare this theorem to other proposed relations between the
cusp slope and the central anisotropy to clarify their applicabilities and
underlying assumptions. The extension of this theorem to tracer populations in
an externally imposed potential is also derived. In particular, for stars
moving in the vicinity of a central black hole, this reduces to gamma >=
beta+(1/2), indicating that an isotropic system in Keplerian potential should
be cusped at least as steep as 1/r^{0.5}. Similar limits have been noticed
before for specific forms of the distribution function, but here we establish
this as a general result.


title: Distribution function of the dark matter

abstract:
  There is good evidence from N-body simulations that the velocity distribution
in the outer parts of halos is radially anisotropic, with the kinetic energy in
the radial direction roughly equal to the sum of that in the two tangential
directions. We provide a simple algorithm to generate such cosmologically
important distribution functions. Introducing r_E(E), the radius of the largest
orbit of a particle with energy E, we show how to write down almost trivially a
distribution function of the form f(E,L)=g(r_E)/L for any spherical model --
including the NFW profile. We in addition give the generic form of the
distribution function for any model with a local density power-law index and
anisotropy parameter, and provide limiting forms appropriate for the central
parts and envelopes of dark matter halos. From those, we argue that, regardless
of the anisotropy, the density fall-off at large radii must evolve to 1/r^4 or
steeper ultimately.


title: Non-Gaussianity of the density distribution in accelerating universes

abstract:
  According to recent observations, the existence of the dark energy has been
considered. Even though we have obtained the constraint of the equation of the
state for dark energy ($p = w \rho$) as $-1 \le w \le -0.78$ by combining WMAP
data with other astronomical data, in order to pin down $w$, it is necessary to
use other independent observational tools. For this purpose, we consider the
$w$ dependence of the non-Gaussianity of the density distribution generated by
nonlinear dynamics. To extract the non-Gaussianity, we follow a semi-analytic
approach based on Lagrangian linear perturbation theory, which provides an
accurate value for the quasi-nonlinear region. From our results, the difference
of the non-Gaussianity between $w = -1$ and $w= -0.5$ is about 4% while that
between $w = -1$ and $w= -0.8$ is about $0.9 %$. For the highly non-linear
region, we estimate the difference by combining this perturbative approach with
N-body simulation executed for our previous paper. From this, we can expect the
difference to be more enhanced in the low-$z$ region, which suggests that the
non-Gaussianity of the density distribution potentially plays an important role
for extracting the information of dark energy.


title: Observations of Stellar Maser Sources with no IRAS Counterpart

abstract:
  We investigated stellar maser sources with no IRAS counterpart at the radio,
middle-infrared, and near-infrared wavelengths. A 43 GHz SiO maser search for
120 2MASS/MSX objects, and 10 OH 1612 MHz sources with no or a very faint MSX
counterpart, resulted in 43 SiO detections: one OH 1612 MHz source, 2
near-infrared stars, and 40 MSX sources. Additional near-infrared J-, H-, and
K-band observations of the OH 1612 MHz sources detected 5 near-infrared
counterparts. Furthermore, middle-infrared imaging observations at 8.8, 9.7,
12.4, and 24.5 micron with the Subaru 8.2-m telescope found counterparts for 2
near-infrared stars with SiO masers, and counterparts for 6 OH 1612 MHz
sources. However, 4 OH 1612 MHz sources were not detected in the sensitive
near- and middle-infrared searches; three of these are relatively strong OH
maser sources for which the positions were known accurately. We conclude that
one of these (OH 028.286-01.801) must be a young object in a star-forming
region.


title:
A two-dimensional electrodynamical outer gap model for gamma-ray
  pulsars: Gamma-ray spectrum

abstract:
  A two-dimensional electrodynamical model is used to study particle
acceleration in the outer magnetosphere of a pulsar. The charge depletion from
the Goldreich-Julian charge density causes a large electric field along the
magnetic field lines. The charge particles are accelerated by the electric
field and emit $\gamma$-rays via the curvature process. Some of the emitted
$\gamma$-rays may collide with $X$-ray photons to make new pairs, which are
accelerated again on the different field lines in the gap and proceed similar
processes. We simulate the pair creation cascade in the meridional plane using
the pair creation mean-free path, in which the $X$-ray photon number density is
proportional to inverse square of radial distance. With the space charge
density determined by the pair creation simulation, we solve the electric
structure of the outer gap in the meridional plane and calculate the curvature
spectrum.
  Because the two-dimensional model can link both gap width along the magnetic
field line and trans-field thickness with the spectral cut-off energy and flux,
we can diagnose both the current through the gap and inclination angle between
the rotational and magnetic axes. We apply the theory to the Vela pulsar. By
comparing the results with the $EGRET$ data, we rule out any cases that have a
large particle injection at the outer boundary. We also suggest the inclination
angle of $\alpha_{inc}\geq65^{\circ}$. The present model predicts the outer gap
starting from near the conventional null charge surface for the Vela pulsar.


title: The ISO 170um Luminosity Function of Galaxies

abstract:
  We constructed a local luminosity function (LF) of galaxies using a
flux-limited sample (S_170 > 0.195Jy) of 55 galaxies at z < 0.3 taken from the
ISO FIRBACK survey at 170um. The overall shape of the 170-um LF is found to be
different from that of the total 60-um LF (Takeuchi et al. 2003): the bright
end of the LF declines more steeply than that of the 60-um LF. This behavior is
quantitatively similar to the LF of the cool subsample of the IRAS PSCz
galaxies. We also estimated the strength of the evolution of the LF by assuming
the pure luminosity evolution (PLE): L(z) \propto (1+z)^Q. We obtained
Q=5.0^{+2.5}_{-0.5} which is similar to the value obtained by recent Spitzer
observations, in spite of the limited sample size. Then, integrating over the
170-um LF, we obtained the local luminosity density at 170um, \rho_L(170um). A
direct integration of the LF gives \rho_L(170um) = 1.1 \times 10^8 h Lsun
Mpc^{-3}, whilst if we assume a strong PLE with Q=5, the value is 5.2 \times
10^7 h Lsun Mpc^{-3}. This is a considerable contribution to the local FIR
luminosity density. By summing up with other available infrared data, we
obtained the total dust luminosity density in the Local Universe,
\rho_L(dust)=1.1 \times 10^8 h Lsun Mpc^{-3}. Using this value, we estimated
the cosmic star formation rate (SFR) density hidden by dust in the Local
Universe. We obtained \rho_SFR(dust) \simeq 1.1-1.2 h \times 10^{-2} Msun
yr^{-1} Mpc^{-3}$, which means that 58.5% of the star formation is obscured by
dust in the Local Universe.


abstract:
  Tidal disruption of dark matter halos around proto-globular clusters in a
halo of a small galaxy is studied in the context of the hierarchical clustering
scenario by using semi-cosmological N-body/SPH simulations assuming the
standard cold dark matter model ($\Omega_0 = 1$). Our analysis on formation and
evolution of the galaxy and its substructures archives until $z = 2.0$. In such
a high-redshift universe, the Einstein-de Sitter universe is still a good
approximation for a recently favored $\Lambda$-dominated universe, and then our
results does not depend on the choice of cosmology. In order to resolve small
gravitationally-bound clumps around galaxies and consider radiative cooling
below $T = 10^4 K$, we adopt a fine mass resolution ($m_{\rm SPH} = 1.12 \times
10^3 \Msun$). Because of the cooling, each clump immediately forms a
`core-halo' structure which consists of a baryonic core and a dark matter halo.
The tidal force from the host galaxy mainly strips the dark matter halo from
clumps and, as a result, theses clumps get dominated by baryons. Once a clump
is captured by the host halo, its mass drastically decreases each pericenter
passage. At $z = 2$, more than half of the clumps become baryon dominated
systems (baryon mass/total mass $> 0.5$). Our results support the tidal
evolution scenario of the formation of globular clusters and baryon dominated
dwarf galaxies in the context of the cold dark matter universe.


title:
Big Bang nucleosynthesis in scalar tensor gravity: the key problem of
  the $^7$Li abundance

abstract:
  Combined with other CMB experiments, the WMAP survey provides an accurate
estimate of the baryon density of the Universe. In the framework of the
standard Big Bang Nucleosynthesis (BBN), such a baryon density leads to
predictions for the primordial abundances of $^{4}$He and D in good agreement
with observations. However, it also leads to a significant discrepancy between
the predicted and observed primordial abundance of $^{7}$Li. Such a discrepancy
is often termed as 'the lithium problem'. In this paper, we analyze this
problem in the framework of scalar-tensor theories of gravity. It is shown that
an expansion of the Universe slightly slower than in General Relativity before
BBN, but faster during BBN, solves the lithium problem and leads to $^4$He and
D primordial abundances consistent with the observational constraints. This
kind of behavior is obtained in numerous scalar-tensor models, both with and
without a self-interaction potential for the scalar field. In models with a
self-interacting scalar field, the convergence towards General Relativity is
ensured without any condition, thanks to an attraction mechanism which starts
to work during the radiation-dominated epoch.


title: Combining weak and strong lensing in cluster potential reconstruction

abstract:
  We propose a method for recovering the two-dimensional gravitational
potential of galaxy clusters which combines data from weak and strong
gravitational lensing. A first estimate of the potential from weak lensing is
improved at the approximate locations of critical curves. The method can be
fully linearised and does not rely on the existence and identification of
multiple images. We use simulations to show that it recovers the surface-mass
density profiles and distributions very accurately, even if critical curves are
only partially known and if their location is realistically uncertain. We
further describe how arcs at different redshifts can be combined, and how
deviations from weak lensing can be included.


title:
Direct magnetic field detection in the innermost regions of an accretion
  disc

abstract:
  Models predict that magnetic fields play a crucial role in the physics of
astrophysical accretion disks and their associated winds and jets. For example,
the rotation of the disk twists around the rotation axis the initially vertical
magnetic field, which responds by slowing down the plasma in the disk and by
causing it to fall towards the central star. The magnetic energy flux produced
in this process points away from the disk, pushing the surface plasma outwards,
leading to a wind from the disk and sometimes a collimated jet. But these
predictions have hitherto not been supported by observations. Here we report
the direct detection of the magnetic field in the core of the protostellar
accretion disk FU Orionis. The surface field reaches strengths of about 1 kG
close to the centre of the disk, and it includes a significant azimuthal
component, in good agreement with recent models. But we find that the field is
very filamentary and slows down the disk plasma much more than models predict,
which may explain why FU Ori fails to collimate its wind into a jet.


title:
NGC 4435: a bulge dominated galaxy with an unforeseen low mass central
  black hole

abstract:
  We present the ionised gas kinematics of the SB0 galaxy NGC 4435 from spectra
obtained with the Space Telescope Imaging Spectrograph. This galaxy has been
selected on the basis of its ground-based spectroscopy, for displaying a
position velocity diagram consistent with the presence of a circumnuclear
Keplerian disc rotating around a supermassive black hole (SMBH). We obtained
the Halpha and [NII](6583) kinematics kinematics in the galaxy nucleus along
the major axis and two parallel offset positions. We built a dynamical model of
the gaseous disc taking into account the whole bidimensional velocity field and
the instrumental set-up. For the mass of the central SMBH we found an upper
limit of 7.5e6 Msun at 3sigma level. This indicates that the mass of SMBH of
NGC 4435 is lower than the one expected from the Mbh-sigma (5e7 Msun) and
near-infrared Mbh- Lbulge (4e7 Msun) relationships.


title:
Reverberation Measurements of the Inner Radius of the Dust Torus in
  Nearby Seyfert 1 Galaxies

abstract:
  The most intense monitoring observations yet made in the optical (UBV) and
near-infrared (JHK) wave bands were carried out for nearby Seyfert1 galaxies of
NGC 5548, NGC 4051, NGC 3227, and NGC 7469. Over three years of observations
with MAGNUM telescope since early 2001, clear time-delayed response of the
K-band flux variations to the V-band flux variations was detected for all of
these galaxies. Their H-K color temperature was estimated to be 1500-1800 K
from the observed flux variation gradients, which supports a view that the bulk
of the K flux should originate in the thermal radiation of hot dust that
surrounds the central engine. Cross-correlation analysis was performed to
quantify the lag time corresponding to the light-travel distance of the hot
dust region from the central engine. The measured lag time is 47-53 days for
NGC 5548, 11-18 days for NGC 4051, about 20 days for NGC 3227, and 65-87 days
for NGC 7469. We found that the lag time is tightly correlated with the optical
luminosity as expected from dust reverberation ($\Delta t \propto L^{0.5}$),
while only weakly with the central virial mass, which suggests that an inner
radius of the dust torus around the active nucleus has a one-to-one
correspondence to central luminosity. In the lag time versus central luminosity
diagram, the K-band lag times place an upper boundary on the similar lag times
of broad-emission lines in the literature. This not only supports the unified
scheme of AGNs, but also implies a physical transition from the BLR out to the
dust torus that encircles the BLR. Furthermore, our V-band flux variations of
NGC 5548 on timescales of up to 10 days are found to correlate with X-ray
variations and delay behind them by one or two days, indicating the thermal
reprocessing of X-ray emission by the central accretion flow.


title: The missing metals problem: II. How many metals are in z ~ 2.2 galaxies?

abstract:
  In the context of the ``missing metals problem'', the contributions of the
UV-selected z=2.2 ``BX'' galaxies and z=2.5 ``distant red galaxies'' (DRGs)
have not been discussed previously. Here we show that: (i) DRGs only make a
marginal contribution to the metal budget (~ 5%); (ii) BX galaxies contribute
as much as 18% to the metal budget; and (iii) the K-bright subsample ($K<20$)
of the BX sample (roughly equivalent to the `BzK' selected samples) contributes
roughly half of this 18%, owing both to their larger stellar masses and higher
metallicities, implying that the rare K-bright galaxies at z>2 are a major
source of metals in the budget. We showed in the first paper of this series
that submm galaxies (SMGs) brighter than 3 mJy contribute ~5% (<9% as an upper
limit) to the metal budget. Adding the contribution of SMGs and damped Ly-alpha
absorbers, to the contribution of UV selected galaxies, implies that at least
30% of the metals (in galaxies) have been accounted for at z=2. The cosmic
metal density thus accounted for is ~ 1.3\times 10^6 \rhosun. This is a lower
limit given that galaxies on the faint-end of the luminosity function are not
included. An estimate of the distribution of metals in local galaxies as a
function luminosity suggests that galaxies with luminosity less than L^{\star}$
contribute about half of the total mass of metals. If the metals in galaxies at
z ~ 2 are similarly distributed then faint galaxies alone cannot solve the
`missing metals problem.' Galaxy populations at z ~ 2 only account for about
50% of the total metals predicted.


title: Curvature effect in structured GRB jets

abstract:
  We study the influence of jet structure on the curvature effect in a
GRB-lightcurve. Using a simple model of jet emissivity, we numerically
calculate lightcurves for a short flash from a relativistic outflow having
various profiles of the Lorentz factor and outflowing energy density (gaussian,
core+power-law). We find that for "on-beam" viewing geometry, with the line of
sight passing through the bright core of the outflow, the shape of the
lightcurve practically does not depend on the jet structure, initially
following the temporal slope 2+delta, where delta is the spectral index. When
the viewing angle is larger than the core, the light curve decaying slope is
shallower. We discuss the implications of our results for the Swift data.


title:
An exceptional X-ray view of the young open cluster NGC 6231: what
  XMM-Newton has taught us

abstract:
  Considered as the core of the Sco OB1 association, the young open cluster NGC
6231 harbours a rich O-type star population. In 2001, the XMM-Newton satellite
targeted the cluster for a nominal duration of about 180 ks. Thanks to the
detector sensitivity, the EPIC cameras provided an unprecedented X-ray view of
NGC 6231, revealing about 600 point-like sources. In this contribution, we
review the main results that have been obtained thanks to this unprecedented
data set. Concerning the O-type stars, we present the latest developments
related to the so-called 'canonical' Lx-Lbol relation. The dispersion around
this relation might actually be much smaller than previously thought. In our
data set, the sole mechanism that yields a significant deviation from this
scheme is wind interaction. It is also the sole mechanism that induces a
significant variation of the early-type star X-ray flux. In a second part of
this contribution, we probe the properties of the optically faint X-ray
sources. Most of them are believed to be low mass pre-main sequence stars.
Their analysis provides direct insight into the star formation history of the
cluster.


title: Globular Clusters in Dwarf and Giant Galaxies

abstract:
  The luminosity distribution of globular clusters shows a dramatic dependence
on parent galaxy luminosity. Dwarf galaxies contain far more faint globulars
than do luminous galaxies. This difference is significant at the 99.7% level.
On the other hand the luminosity distribution of globular clusters in dwarf
galaxies does not appear to depend strongly on their host's morphological type.
The dichotomy of globular cluster masses occurs at a host galaxy mass of ~ 4 x
10^8 solar masses, which is almost two orders of magnitude lower than the onset
of the dichotomy in globular color characteristics at ~ 3 x 10^10 solar masses
that was recently noted by Forbes.


title: Diameters of Open Star Clusters

abstract:
  The present paper presents a tabulation of data on all 600 Galactic open
clusters for which it is presently possible to calculate linear diameters. As
expected, the youngest `clusters' with ages < 15 Myr, contain a significant
(greater than or equal to 20%) admixture of associations. Among
intermediate-age clusters, with ages in the range 15 Myr to 1.5 Gyr, the median
cluster diameter is found to increase with age. Small compact clusters are rare
among objects with ages > 1.5 Gyr. Open clusters with ages > 1 Gyr appear to
form what might be termed a `cluster thick disk', part of which consistst of
objects that were probably captured gravitationally by the main body of the
Galaxy.


title:
What can be learned from the lensed cosmic microwave background B-mode
  polarization power spectrum?

abstract:
  The effect of weak gravitational lensing on the cosmic microwave background
(CMB) temperature anisotropies and polarization will provide access to
cosmological information that cannot be obtained from the primary anisotropies
alone. We compare the information content of the lensed B-mode polarization
power spectrum, properly accounting for the non-Gaussian correlations between
the power on different scales, with that of the unlensed CMB fields and the
lensing potential. The latter represent the products of an (idealised) optimal
analysis that exploits the lens-induced non-Gaussianity to reconstruct the
fields. Compressing the non-Gaussian lensed CMB into power spectra is wasteful
and leaves a tight degeneracy between the equation of state of dark energy and
neutrino mass that is much stronger than in the more optimal analysis. Despite
this, a power spectrum analysis will be a useful first step in analysing future
B-mode polarization data. For this reason, we also consider how to extract
accurate parameter constraints from the lensed B-mode power spectrum. We show
with simulations that for cosmic-variance-limited measurements of the lensed
B-mode power, including the non-Gaussian correlations in existing likelihood
approximations gives biased parameter results. We develop a more refined
likelihood approximation that performs significantly better. This new
approximation should also be of more general interest in the wider context of
parameter estimation from Gaussian CMB data.


title:
Multivariate Analysis of Globular Cluster's Horizontal Branch
  Morphology: searching for the second parameter

abstract:
  The interpretation of globular cluster horizontal branch (HB) morphology is a
classical problem that can significantly blur our understanding of stellar
populations. In this paper, we present a new multivariate analysis connecting
the effective temperature extent of the HB with other cluster parameters. The
work is based on Hubble Space Telescope photometry of 54 Galactic globular
clusters. The present study reveals an important role of the total mass of the
globular cluster on its HB morphology. More massive clusters tend to have HBs
more extended to higher temperatures. For a set of three input variables
including the temperature extension of the HB, [Fe/H] and M_V, the first two
eigenvectors account for the 90% of the total sample variance. Possible effects
of cluster self-pollution on HB morphology, eventually stronger in more massive
clusters, could explain the results here derived.


title: Principal Component Analysis of Weak Lensing Surveys

abstract:
  We study degeneracies between cosmological parameters and measurement errors
from cosmic shear surveys using a principal component analysis of the Fisher
matrix. We simulate realistic survey topologies with non-uniform sky coverage,
and quantify the effect of survey geometry, depth and noise from intrinsic
galaxy ellipticities on the parameter errors. This analysis allows us to
optimise the survey geometry. Using the shear two-point correlation functions
and the aperture mass dispersion, we study various degeneracy directions in a
multi-dimensional parameter space spanned by Omega_m, Omega_Lambda, sigma_8,
the shape parameter Gamma, the spectral index n_s, along with parameters that
specify the distribution of source galaxies. If only three parameters are to be
obtained from weak lensing data, a single principal component is dominant and
contains all information about the main parameter degeneracies and their
errors. The variance of the dominant principal component of the Fisher matrix
shows a minimum for survey strategies which have small cosmic variance and
measure the shear correlation up to several degrees [abridged].


title: A new radial system of dark globules in Monoceros

abstract:
  Aims. We analyze the LBN 978 HII region in order to study the HII/molecular
cloud interaction.
  Methods. We used the IAC-80 telescope to image the region with narrow-band
filters and the Very Large Array to obtain a radio continuum map at 3.6 cm. We
also used the DSS2 red images and the NRAO VLA Sky Survey at 20 cm.
  Results. We have discovered a new radial system of dark globules associated
with the LBN 978 HII region, containing a group of at least eight cometary
bright-rimmed globules with the same morphological type. The brightest source
is also detected in the radio continuum. Analysis of optical and radio emission
suggest that this object is photoionized by HD 47432, the central star of the
LBN 978 HII region.


title: A search for periodicity in the light curves of selected blazars

abstract:
  We present an analysis of multifrequency light curves of the sources 2223-052
(3C 446), 2230+114 (CTA 102), and 2251+158 (3C 454.3), which had shown evidence
of quasi-periodic activity. The analysis made use of data from the University
of Michican Radio Astronomy Observatory (USA) at 4.8, 8, and 14.5 GHz, as well
as the Metsahovi Radio Astronomy Observatory (Finland) at 22 and 37 GHz.
Application of two different methods (the discrete autocorrelation function and
the method of Jurkevich) both revealed evidence for periodicity in the flux
variations of these sources at essentially all frequencies. The periods derived
for at least two of the sources -- 2223-052 and 2251+158-- are in good
agreement with the time interval between the appearance of successive VLBI
components. The derived periods for 2251+158 (P = 12.4 yr and 2223-052 (P = 5.8
yr) coincide with the periods found earlier by other authors based on optical
light curves.


title: Radiative zone solar magnetic fields and g-modes

abstract:
  We consider a generalized model of seismic-wave propagation that takes into
account the effect of a central magnetic field in the Sun. We determine the
g-mode spectrum in the perturbative magnetic field limit using a
one-dimensional Magneto-Hydrodynamics (MHD) picture. We show that central
magnetic fields of about 600-800 kG can displace the pure g-mode frequencies by
about 1%, as hinted by the helioseismic interpretation of GOLF observations.


title: Comments on the tethered galaxy problem

abstract:
  In a recent paper Davis et al. make the counter intuitive assertion that a
galaxy held `tethered' at a fixed distance from our own could emit blueshifted
light. Moreover, this effect may be derived from the simplest
Friedmann-Robertson-Walker spacetimes and the (0.3,0.7) case which is believed
to be a good late time model of our own universe.
  In this paper we recover the previous authors' results in a more transparent
form. We show how their results rely on a choice of cosmological distance scale
and revise the calculations in terms of observable quantities which are
coordinate independent. By this method we see that, although such a tethering
would reduce the redshift of a receding object, it would not do so sufficiently
to cause the proposed blueshift. The effect is also demonstrated to be much
smaller than conjectured below the largest intergalactic scales. We also
discuss some important issues, raised by this scenario, relating to the
interpretation of redshift and distance in relativistic cosmology.


title: Resonance Overlap is Responsible for Ejecting Planets in Binary Systems

abstract:
  A planet orbiting around a star in a binary system can be ejected if it lies
too far from its host star. We find that instability boundaries first obtained
in numerical studies can be explained by overlap between sub-resonances within
mean-motion resonances (mostly of the j:1 type). Strong secular forcing from
the companion displaces the centroids of different sub-resonances, producing
large regions of resonance overlap. Planets lying within these overlapping
regions experience chaotic diffusion, which in most cases leads to their
eventual ejection. The overlap region extends to shorter-period orbits as
either the companion's mass or its eccentricity increase. Our analytical
calculations reproduce the instability boundaries observed in numerical studies
and yield the following two additional results. Firstly, the instability
boundary as a function of eccentricity is jagged; thus, the widest stable orbit
could be reduced from previously quoted values by as much as 20%. Secondly,
very high order resonances (e.g., 50:3) do not significantly modify the
instability boundary despite the fact that these weak resonances can produce
slow chaotic diffusion which may be missed by finite-duration numerical
integrations. We present some numerical evidence for the first result. More
extensive experiments are called for to confirm these conclusions. For the
special case of circular binaries, we find that the Hill criterion (based on
the critical Jacobi integral) yields an instability boundary that is very
similar to that obtained by resonance overlap arguments, making the former both
a necessary and a sufficient condition for planet instability.


title:
Magnetar giant flares and afterglows as relativistic magnetized
  explosions

abstract:
  (Abridged) We propose that giant flares on Soft Gamma-Ray Repeaters produce
relativistic, strongly magnetized, weakly baryon loaded magnetic clouds,
somewhat analogous to solar coronal mass ejection (CME) events. Flares are
driven by unwinding of internal non-potential magnetic fields which leads to
slow build-up of magnetic energy outside of the neutron star. For large
magnetospheric currents, corresponding to a large twist of external magnetic
field, magnetosphere becomes dynamically unstable on \Alfven crossing times
scale of inner magnetosphere, $t_A \sim R_{NS}/c \sim 30 \mu$sec. Released
magnetic energy results in formation of a strongly magnetized, pair-loaded,
quasi-spherically expanding flux rope, topologically connected by magnetic
field to the neutron star during the prompt flare emission. Magnetic stresses
of the tied flux rope lead to late collimation of the expansion, on time scales
longer than giant flare duration. Relativistic bulk motion of the expanding
magnetic cloud, directed at an angle $\theta \sim 135^\circ$ to the line of
sight (away from the observer), results in a strongly non-spherical forward
shock with observed non-relativistic apparent expansion and bulk motion
velocities $\beta_{app} \sim \cot \theta/2 \sim 0.4 $ at times of first radio
observations approximately one week after the burst. Interaction with a shell
of wind-shocked ISM and then with the unshocked ISM leads to deceleration to
non-relativistic velocities approximately one month after the flare.


title:
Resolving the Kinematic Distance Ambiguity of Southern Massive Young
  Stellar Object Candidates

abstract:
  We investigate the use of HI data to resolve the near/far ambiguity in
kinematic distances of massive young stellar object (MYSO) candidates.
Kinematic distances were obtained from 13CO 1-0 spectral line observations with
the Mopra Telescope towards 94 candidates selected from the Red MSX Source
(RMS) survey in the fourth Galactic quadrant. HI data from the Southern
Galactic Plane Survey (SPGS) was used in conjunction with the HI
self-absorption technique to determine the near or far distance. We resolved
the kinematic distance ambiguity to 70% of the sources. We can also
simultaneously solve for any multiple line-of-sight component sources. We
discuss the advantages and disadvantages of this technique in comparison with
other methods, and also perform confidence checks on the reliability of using
the HI self-absorption technique. We examined the projected location of these
sources in both the Galactic plane and longitude-velocity diagrams to ascertain
any recognisable spiral arm pattern. Although no obvious spiral pattern was
found when compared to that proposed by Cordes & Lazio, far distance sources
tended to lie on or near spiral arm loci. Near distance sources, however, had
peculiar velocity uncertainties consistent with the separation between the
spiral arms themselves. The longitude-velocity plot shows a more consistent
picture, with tangent points of the spiral arm loci easily seen. We conclude
that using the HI self-absorption technique to determine kinematic distance
ambiguities is a quick and reliable method in most cases, with an 80% success
rate in determining the correct designation of whether an object is at the near
or far distance.


title: Roche Lobe Sizes in Deep-MOND Gravity

abstract:
  MOdified Newtonian Dynamics (MOND) is evolving from an empirical to a decent
theory respecting fundamental physics after Bekenstein (2004) showed that
lensing and Hubble expansion can be modeled rigourously in a Modified
Relativity. The degeneracy of MOND with Dark Matter can be broken if we examine
the non-linear MONDian Poisson's equation in detail. Here we study the effect
of tides for a binary stellar system or a baryonic satellite-host galaxy
system. We show that the Roche lobe is more squashed than the Newtonian case
due to the anisotropic dilation effect in deep-MOND. We prove analytically that
the Roche lobe volume scales linearly with the "true" baryonic mass ratio in
both Newtonian and deep-MOND regimes, insensitive to the modification to the
inertia mass. Hence accurate Roche radii of satellites can break the degeneracy
of MOND and dark matter theory. Globular clusters and dwarf galaxies of
comparable luminosities and distances show a factor of ten scatter in limiting
radii; this is difficult to explain in any "mass-tracing-light" universe. The
results here are generalizable to the intermediate MOND regime for a wide class
of gravity modification function $\mu(g)$ (Zhao and Tian, astro-ph/0511754).


title: Complex supergravity quintessence models confronted with Sn Ia data

abstract:
  A class of supergravity inspired quintessence models is studied by comparing
to cosmological data. The set of considered models includes several previously
studied quintessential potentials, as well as the $\Lambda$CDM model. We find
that even though the commonly studied supergravity inspired quintessence models
fit the data better than the $\Lambda$CDM model, they are a relatively poor fit
when compared to the best fit model in the studied class. Our results suggest a
low energy scale, less than ${\cal{M}}\sim 1$ TeV, for the effective
supergravity potential.


title:
Spectral shape of the UV ionizing background and OVI absorbers at z ~
  1.5 towards HS0747+4259

abstract:
  We report on high resolution spectra of the bright QSO HS0747+4259 (zem =
1.90, V = 15.8) observed to search for intermediate redshift OVI absorption
systems. The spectra were obtained by means of the Space Telescope Imaging
Spectrograph (STIS) at the Hubble Space Telescope (HST) and the High Resolution
Echelle Spectrometer (HIRES) at the W. M. Keck telescope. We identify 16 OVI
systems in the range 1.07 <= z <= 1.87. Among them, six systems with zabs =
1.46-1.8 exhibit a sufficient number of lines of different ionic transitions to
estimate the shape of the ionizing radiation field in the range 1 Ryd < E < 10
Ryd. All recovered UV ionizing spectra are characterized by the enhanced
intensity at E > 3 Ryd compared to the model spectrum of Haardt and Madau
(1996). This is in line with the observational evidence of a deficiency of
strong Ly-alpha absorbers with N(HI) > 10^{15} cm^{-2}, at z < 2. The UV
background shows significant local variations: the spectral shape estimated at
z = 1.59 differs from that obtained at z = 1.81 and 1.73. A possible cause of
these variations is the presence of a QSO/AGN at z ~= 1.54-1.59 close to the
line of sight. No features favoring the input of stellar radiation to the
ionizing background are detected, limiting the escape fraction of the galactic
UV photons to f_esc < 0.05.


title:
Reconciliation of Statistical Mechanics and Astro-Physical Statistics.
  The errors of conventional canonical thermostatistics

abstract:
  Conventional thermo-statistics address infinite homogeneous systems within
the canonical ensemble. (Only in this case this is equivalent to the
fundamental microcanonical ensemble.) However, some 170 years ago the original
motivation of thermodynamics was the description of steam engines, i.e. boiling
water. Its essential physics is the separation of the gas phase from the
liquid. Of course, boiling water is inhomogeneous and as such cannot be treated
by conventional thermo-statistics. Then it is not astonishing, that a phase
transition of first order is signaled canonically by a Yang-Lee singularity.
Thus it is only treated correctly by microcanonical Boltzmann-Planck
statistics. It turns out that the Boltzmann-Planck statistics is much richer
and gives fundamental insight into statistical mechanics and especially into
entropy. This can be done to a far extend rigorously and analytically. As no
extensivity, no thermodynamic limit, no concavity, no homogeneity is needed, it
also applies to astro-physical systems. The deep and essential difference
between ``extensive'' and ``intensive'' control parameters, i.e. microcanonical
and canonical statistics, is exemplified by rotating, self-gravitating systems.
In the present paper the necessary appearance of a convex entropy S(E) and
negative heat capacity at phase separation in small as well macroscopic systems
independently of the range of the force is pointed out. Thus the old puzzle of
stellar statistics is finally solved, the appearance of negative heat capacity
which is forbidden and cannot appear in the canonical formalism.


title:
NGC 2401: A template of the Norma-Cygnus Arm's young population in the
  Third Galactic Quadrant

abstract:
  Based on a deep optical CCD (UBV(RI)_C) photometric survey and on the
Two-Micron All-Sky-Survey (2MASS) data we derived the main parameters of the
open cluster NGC 2401. We found this cluster is placed at 6.3 $\pm$ 0.5 kpc
(V_O - M_V = 14.0 \pm 0.2) from the Sun and is 25 Myr old, what allows us to
identify NGC 2401 as a member of the young population belonging to the
innermost side of the extension of the Norma-Cygnus spiral--arm in the Third
Galactic Quadrant. A spectroscopic study of the emission star LSS 440 that lies
in the cluster area revealed it is a B0Ve star; however, we could not confirm
it is a cluster member. We also constructed the cluster luminosity function
(LF) down to $V \sim 22$ and the cluster initial mass function (IMF) for all
stars with masses above $M \sim 1-2 M_{\sun}$. It was found that the slope of
the cluster IMF is $x \approx 1.8 \pm 0.2$. The presence of a probable PMS star
population associated to the cluster is weakly revealed.


title:
Shallow Decay of Early X-ray Afterglows from Inhomogeneous Gamma-Ray
  Burst Jets

abstract:
  Almost all the X-ray afterglows of gamma-ray bursts (GRBs) observed by the
Swift satellite have a shallow decay phase in the first thousands of seconds.
We show that in an inhomogeneous jet (multiple-subjet or patchy-shell) model
the superposition of the afterglows of off-axis subjets (patchy shells) can
have the shallow decay phase. The necessary condition for obtaining the shallow
decay phase is that gamma-ray bright subjets (patchy shells) should have
gamma-ray efficiency higher than previously estimated, and should be surrounded
by gamma-ray dim subjets (patchy shells) with low gamma-ray efficiency. Our
model predicts that events with dim prompt emission have the conventional
afterglow light curve without the shallow decay phase like GRB 050416A.


title:
Hadronic Cosmic Ray Interactions Near the LHC Energy Region and in the
  UHE Domain of Giant EAS

abstract:
  The fluctuations of $\gamma$ ray families simulated with CORSIKA in the
energy region 3$\times10^{15}-10^{17}$eV on the basis of standard $Ln s$
collider physics exhibits alignments of secondaries in the stratosphere and at
ground level. The remarkable event registrated on the Concorde doesn't fit well
however those cases ; The possible hints of new mechanisms, especially the
valence diquark breaking, are considered. Observing that the extrapolation of
the original cosmic ray primary spectrum derived from the size spectrum
measured in the Akeno classical EAS array coincides with the spectrum measured
recently by the Hires Stereo experiment, we point out a possible overestimation
of the primary energy in inclined showers of the surface arrays like AGASA.


title:
Halpha surface photometry of galaxies in nearby clusters. V: the survey
  completion

abstract:
  We present the Halpha imaging observations of 273 late-type galaxies in the
nearby rich galaxy clusters Virgo, A1367, Coma, Cancer, Hercules and in the
Great Wall, carried out primarily with the 2.1m telescope of the San Pedro
Martir Observatory (SPM) and with the ESO/3.6m telescope. We derived the
Halpha+[NII] fluxes and equivalent widths. The Halpha survey reached completion
for an optically selected sample of nearby galaxies in and outside rich
clusters. Taking advantage of the completeness of the data set, the dependence
of Halpha properties on the Hubble type was determined for late-type galaxies
in the Virgo cluster. Differences in the gaseous content partly account for the
large scatter of the Halpha E.W. within each Hubble-type class. We studied the
radial distributions of the Halpha E.W. around Coma+A1367 and the Virgo
clusters in two luminosity bins. Luminous galaxies show a decrease in their
average Halpha E.W. in the inner 1 virial radius, while low-luminosity galaxies
do not show this trend.


title: Completing HI observations of galaxies II. The Coma Supercluster

abstract:
  High sensitivity 21-cm HI line observations, with an rms noise level of \sim
0.5 mJy, were made of 35 spiral galaxies in the Coma Supercluster, using the
refurbished Arecibo telescope, which resulted in the detection of 25 objects.
These data, combined with the measurements available from the literature,
provide the set of HI data for 94% of all late-type galaxies in the Coma
Supercluster with an apparent photographic magnitude m_p <15.7 mag. We confirm
that the typical scale of HI deficiency around the Coma cluster is 2 Mpc, i.e.
one virial radius. Comparing the HI mass function (HIMF) of cluster with
non-cluster members of the Coma Supercluster we detect a shortage of high HI
mass galaxies among cluster members that can be ascribed to the pattern of HI
deficiency found in rich clusters.


title:
The weak INTEGRAL bursts GRB040223 and GRB040624: an emerging population
  of dark afterglows

abstract:
  We report here gamma-ray, X-ray and near-infrared observations of GRB040223
along with gamma-ray and optical observations of GRB040624. GRB040223 was
detected by INTEGRAL close to the Galactic plane and GRB040624 at high Galactic
latitude. Analyses of the prompt emission detected by the IBIS instrument on
INTEGRAL are presented for both bursts. The two GRBs have long durations, slow
pulses and are weak. The gamma-ray spectra of both bursts are best fit with
steep power-laws, implying they are X-ray rich. GRB040223 is among the weakest
and longest of INTEGRAL GRBs. The X-ray afterglow of this burst was detected 10
hours after the prompt event by XMM-Newton. The measured spectral properties
are consistent with a column density much higher than that expected from the
Galaxy, indicating strong intrinsic absorption. We carried out near-infrared
observations 17 hours after the burst with the NTT of ESO, which yielded upper
limits. Given the intrinsic absorption, we find that these limits are
compatible with a simple extrapolation of the X-ray afterglow properties. For
GRB040624, we carried out optical observations 13 hours after the burst with
FORS 1 and 2 at the VLT, and DOLoRes at the TNG, again obtaining upper limits.
We compare these limits with the magnitudes of a compilation of promptly
observed counterparts of previous GRBs and show that they lie at the very faint
end of the distribution. These two bursts are good examples of a population of
bursts with dark or faint afterglows that are being unveiled through the
increasing usage of large diameter telescopes engaged in comprehensive
observational programmes.


title: Mass distribution in nearby Abell clusters

abstract:
  We study the mass distribution in six nearby (z<0.06) relaxed Abell clusters
of galaxies A0262, A0496, A1060, A2199, A3158 and A3558. Given the dominance of
dark matter in galaxy clusters we approximate their total density distribution
by the NFW formula characterized by virial mass and concentration. We also
assume that the anisotropy of galactic orbits is reasonably well described by a
constant and that galaxy distribution traces that of the total density. Using
the velocity and position data for 120-420 galaxies per cluster we calculate,
after removal of interlopers, the profiles of the lowest-order even velocity
moments, dispersion and kurtosis. We then reproduce the velocity moments by
jointly fitting the moments to the solutions of the Jeans equations. Including
the kurtosis in the analysis allows us to break the degeneracy between the mass
distribution and anisotropy and constrain the anisotropy as well as the virial
mass and concentration. The method is tested in detail on mock data extracted
from N-body simulations of dark matter haloes. We find that the best-fitting
galactic orbits are remarkably close to isotropic in most clusters. Using the
fitted pairs of mass and concentration parameters for the six clusters we
conclude that the trend of decreasing concentration for higher masses found in
cosmological N-body simulations is consistent with the data. By scaling the
individual cluster data by mass we combine them to create a composite cluster
with 1465 galaxies and perform a similar analysis on such sample. The estimated
concentration parameter then lies in the range 1.5 < c < 14 and the anisotropy
parameter in the range -1.1 < \beta < 0.5 at the 95 percent confidence level.


title:
Spectral evolution of star clusters in the Large Magellanic Cloud: I.
  Blue concentrated clusters in the age range 40-300 Myr

abstract:
  Integrated spectroscopy of a sample of 17 blue concentrated Large Magellanic
Cloud (LMC) clusters is presented and its spectral evolution studied. The
spectra span the range ~3600-6800A with a resolution of ~14A FWHM, being used
to determine cluster ages and, in connection with their spatial distribution,
to explore the LMC structure and cluster formation history. Cluster reddening
values were estimated by interpolation, using the available extinction maps. We
used two methods to derive cluster ages: (i) template matching, in which line
strengths and continuum distribution of the cluster spectra were compared and
matched to those of template clusters with known astrophysical properties, and
(ii) equivalent width (EW) method, in which new age/metallicity calibrations
were used together with diagnostic diagrams involving the sum of EWs of
selected spectral lines (KCaII, G band (CH), MgI, Hdelta, Hgamma and Hbeta).
The derived cluster ages range from 40Myr (NGC2130 and SL237) to 300Myr
(NGC1932 and SL709), a good agreement between the results of the two methods
being obtained. Combining the present sample with additional ones indicates
that cluster deprojected distances from the LMC center are related to age in
the sense that inner clusters tend to be younger. Spectral libraries of star
clusters are useful datasets for spectral classifications and extraction of
parameter information for target star clusters and galaxies. The present
cluster sample complements previous ones, in an effort to gather a spectral
library with several clusters per age bin.


title: Bimodal spectral variability of Cygnus X-1 in an intermediate state

abstract:
  We report the results of an observation of Cygnus X-1 with INTEGRAL, that we
combine with simultaneous radio observations with the Ryle telescope. Both
spectral and variability properties of the source indicate that Cygnus X-1 was
in an Intermediate State. The INTEGRAL spectrum shows a high-energy cut-off or
break around 100 keV. The shape of this cut-off differs from pure thermal
Comptonisation, suggesting the presence of a non-thermal component at higher
energies.The average broad band spectrum is well represented by hybrid
thermal/non-thermal Comptonisation models. During the 4 day long observation
the source showed an important spectral and flux variability. A principal
component analysis demonstrates that most of this variability occurs through 2
independent modes. The first mode consists in changes in the overall luminosity
on time scale of hours with almost constant spectra that are strikingly
uncorrelated with the variable radio flux. We interpret this variability mode
as variations of the dissipation rate in the corona. The second variability
mode consists in a pivoting of the spectrum around 10 keV. It acts on a longer
time-scale: initially soft, the spectrum hardens in the first part of the
observation and then softens again. This pivoting pattern is strongly
correlated with the radio (15 GHz) emission: radio fluxes are stronger when the
INTEGRAL spectrum is harder. We propose that the pivoting mode represents a
'mini' state transition from a nearly High Soft State to a nearly Low Hard
State, and back. This mini-transition would be caused by changes in the soft
cooling photons flux in the hot Comptonising plasma associated with an increase
of the temperature of the accretion disc. The jet power then appears to be
anti-correlated with the disc luminosity and unrelated to the coronal power.


title:
Foreground contamination of the WMAP CMB maps from the perspective of
  the matched circle test

abstract:
  WMAP has provided CMB maps of the full sky. The raw data is subject to
foreground contamination, in particular near to the Galactic plane. Foreground
cleaned maps have been derived, e.g., the internal linear combination (ILC) map
of Bennett et al. and the reduced foreground TOH map of Tegmark et al. Using S
statistics we examine whether residual foreground contamination is left over in
the foreground cleaned maps. In particular, we specify which parts of the
foreground cleaned maps are sufficiently accurate for the circle-in-the-sky
signature. We generalise the S statistic, called D statistic, such that the
circle test can deal with CMB maps in which the contaminated regions of the sky
are excluded with masks.


title: A Dimensional study of Disk Galaxies

abstract:
  We present a highly simplified model of the dynamical structure of a disk
galaxy where only two parameters fully determine the solution, mass and angular
momentum. We show through simple physical scalings that once the mass has been
fixed, the angular momentum parameter $\lambda$ is expected to regulate such
critical galactic disk properties as colour, thickness of the disk and disk to
bulge ratio. It is hence expected to be the determinant physical ingredient
resulting in a given Hubble type. A simple analytic estimate of $\lambda$ for
an observed system is provided. An explicit comparison of the distribution of
several galactic parameters against both Hubble type and $\lambda$ is performed
using observed galaxies. Both such distributions exhibit highly similar
characteristics for all galactic properties studied, suggesting $\lambda$ as a
physically motivated classification parameter for disk galaxies.


title:
A New Multidimensional Hydrodynamics code based on Semidiscrete Central
  and WENO schemes

abstract:
  We present a new multidimensional classical hydrodynamics code based on
Semidiscrete Central Godunov-type schemes and high order Weighted Essentially
Non-oscillatory (WENO) data reconstruction. This approach is a lot simpler and
easier to implement than other Riemann solver based methods. The algorithm
incorporates elements of the Piecewise Parabolic Method (PPM) in the
reconstruction schemes to ensure robustness and applications of high order
reconstruction schemes. A number of one and two dimensional benchmark tests
have been carried out to verify the code. The tests show that this new
algorithm and code is comparable in accuracy, efficiency and robustness to
others.


title: An Integrated Spectrophotometric Survey of Nearby Star-Forming Galaxies

abstract:
  We present integrated optical spectrophotometry for a sample of 417 nearby
galaxies. Our observations consist of spatially integrated, S/N=10-100
spectroscopy between 3600 and 6900 Angstroms at ~8 Angstroms FWHM resolution.
In addition, we present nuclear (2.5"x2.5") spectroscopy for 153 of these
objects. Our sample targets a diverse range of galaxy types, including
starbursts, peculiar galaxies, interacting/merging systems, dusty,
infrared-luminous galaxies, and a significant number of normal galaxies. We use
population synthesis to model and subtract the stellar continuum underlying the
nebular emission lines. This technique results in emission-line measurements
reliably corrected for stellar absorption. Here, we present the integrated and
nuclear spectra, the nebular emission-line fluxes and equivalent widths, and a
comprehensive compilation of ancillary data available in the literature for our
sample. In a series of subsequent papers we use these data to study optical
star-formation rate indicators, nebular abundance diagnostics, the
luminosity-metallicity relation, the dust properties of normal and starburst
galaxies, and the star-formation histories of infrared-luminous galaxies.


title: Optical Star-Formation Rate Indicators

abstract:
  Using integrated optical spectrophotometry for 412 star-forming galaxies at
z~0, and fiber-aperture spectrophotometry for 120,846 SDSS galaxies at z~0.1,
we investigate the H-alpha, H-beta, [O II] 3727, and [O III] 5007 nebular
emission lines and the U-band luminosity as quantitative star-formation rate
(SFR) indicators. We demonstrate that the extinction-corrected H-alpha
luminosity is a reliable SFR tracer even in highly obscured star-forming
galaxies. We find that variations in dust reddening dominate the systematic
uncertainty in SFRs derived from the observed H-beta, [O II], and U-band
luminosities, producing a factor of ~1.7, ~2.5, and ~2.1 scatter in the mean
transformations, respectively. We show that [O II] depends weakly on variations
in oxygen abundance over a wide range in metallicity, 12+log(O/H)=8.15-8.7 dex
(Z/Z_sun=0.28-1.0), and that in this metallicity interval galaxies occupy a
narrow range in ionization parameter (-3.8<log U<-2.9 dex). We show that the
scatter in [O III] 5007 as a SFR indicator is a factor of 3-4 due to its
sensitivity to metal abundance and ionization. We develop empirical SFR
calibrations for H-beta and [O II] parameterized in terms of the B-band
luminosity, which remove the systematic effects of reddening and metallicity,
and reduce the SFR scatter to +/-40% and +/-90%, respectively, although
individual galaxies may deviate substantially from the median relations.
Finally, we compare the z~0 relations between blue luminosity and reddening,
ionization, and [O II]/H-alpha ratio against measurements at z~1 and find broad
agreement. (Abridged.)


title: Integrated Nebular Abundances of Disk Galaxies

abstract:
  We study whether integrated optical spectroscopy of a disk galaxy can be used
to infer the mean, or characteristic gas-phase oxygen abundance in the presence
of systematic effects such as spatial abundance variations, contributions to
the integrated emission-line spectrum from diffuse-ionized gas, and dust
attenuation. Our sample consists of 14 nearby disk galaxies with integrated
spectrophotometry, and observations of more than 250 individual HII regions
culled from the literature. We consider both theoretical and empirical
strong-line abundance calibrations based on the R23=([OII]+[OIII])/H-beta
parameter. We find that the integrated oxygen abundance correlates well with
the gas-phase abundance measured at a fixed galactocentric radius, as
determined by the HII-region abundance gradient. The typical scatter in the
correlation is +/-0.1 dex, independent of the abundance calibration, or whether
the observed integrated emission-line fluxes, the reddening-corrected fluxes,
or the emission-line equivalent widths are used. Integrated abundances based on
the observed fluxes or equivalent widths, however, are susceptible to
additional systematic effects of order 0.05-0.1 dex, at least for the range of
reddenings and stellar populations spanned by our sample. Unlike the integrated
R23 parameter, we find that the integrated [NII]/H-alpha and [SII]/H-alpha
ratios are enhanced with respect to line-ratios typical of HII regions,
consistent with a modest contribution from diffuse-ionized gas emission. We
conclude that the R23 parameter can be used to reliably measure the gas-phase
abundances of distant star-forming galaxies.


title: Identifying Primordial Substructure in NGC 2264

abstract:
  We present new Spitzer Space Telescope observations of the young cluster
NGC2264. Observations at 24 micron with the Multiband Imaging Photometer has
enabled us to identify the most highly embedded and youngest objects in
NGC2264. This letter reports on one particular region of NGC2264 where bright
24 micron sources are spatially configured in curious linear structures with
quasi-uniform separations. The majority of these sources (~60% are found to be
protostellar in nature with Class I spectral energy distributions. Comparison
of their spatial distribution with sub-millimeter data from Wolf-Chase (2003)
and millimeter data from Peretto et al. (2005) shows a close correlation
between the dust filaments and the linear spatial configurations of the
protostars, indicating that star formation is occurring primarily within dense
dusty filaments. Finally, the quasi-uniform separations of the protostars are
found to be comparable in magnitude to the expected Jeans length suggesting
thermal fragmentation of the dense filamentary material.


title:
The rapid fading of V1647 Orionis: the sudden end of a FUor-type
  eruption?

abstract:
  V1647 Ori is a young eruptive star, which went into outburst at the end of
2003. Since then, the object is gradually fading. In October 2005, however,
V1647 Ori started a very rapid fading, approximately 1 mag/month in I_C as
opposed to 0.1 mag/month previously. According to the colour changes, the rapid
fading is not caused by increasing extinction, which suggests that the observed
brightness changes are intrinsic. Supposing that the fading rate remains
unchanged, the star will return to the pre-outburst state by mid-December 2005.


title: An Overdensity of Galaxies near the Most Distant Radio-Loud Quasar

abstract:
  A five square arcminute region around the luminous radio-loud quasar SDSS
J0836+0054 (z=5.8) hosts a wealth of associated galaxies, characterized by very
red (1.3 < i_775 - z_{850} < 2.0) color. The surface density of these z~5.8
candidates is approximately six times higher than the number expected from deep
ACS fields. This is one of the highest galaxy overdensities at high redshifts,
which may develop into a group or cluster. We also find evidence for a
substructure associated with one of the candidates. It has two very faint
companion objects within two arcseconds, which are likely to merge. The finding
supports the results of a recent simulation that luminous quasars at high
redshifts lie on the most prominent dark-matter filaments and are surrounded by
many fainter galaxies. The quasar activity from these regions may signal the
buildup of a massive system.


title: Probing neutrino masses with CMB lensing extraction

abstract:
  We evaluate the ability of future cosmic microwave background (CMB)
experiments to measure the power spectrum of large scale structure using
quadratic estimators of the weak lensing deflection field. We calculate the
sensitivity of upcoming CMB experiments such as BICEP, QUaD, BRAIN, ClOVER and
PLANCK to the non-zero total neutrino mass M_nu indicated by current neutrino
oscillation data. We find that these experiments greatly benefit from lensing
extraction techniques, improving their one-sigma sensitivity to M_nu by a
factor of order four. The combination of data from PLANCK and the SAMPAN
mini-satellite project would lead to sigma(M_nu) = 0.1 eV, while a value as
small as sigma(M_nu) = 0.035 eV is within the reach of a space mission based on
bolometers with a passively cooled 3-4 m aperture telescope, representative of
the most ambitious projects currently under investigation. We show that our
results are robust not only considering possible difficulties in subtracting
astrophysical foregrounds from the primary CMB signal but also when the minimal
cosmological model (Lambda Mixed Dark Matter) is generalized in order to
include a possible scalar tilt running, a constant equation of state parameter
for the dark energy and/or extra relativistic degrees of freedom.


title: The Curvaton Web

abstract:
  We discuss nontrivial features of the large scale structure of the universe
in the simplest curvaton model proposed in our paper astro-ph/9610219. The
amplitude of metric perturbations in this model takes different values in
different parts of the universe. The spatial distribution of the amplitude
looks like a web consisting of exponentially large cells. Depending on the
relation between the cell size l_0 and the scale of the horizon l_H, one may
either live in a part of the universe dominated by gaussian perturbations
(inside a cell with l_0 >> l_H), or in the universe dominated by nongaussian
perturbations (for l_0 << l_H). We show that the curvaton contribution to the
total amplitude of adiabatic density perturbations can be strongly suppressed
if the energy density of the universe prior to the curvaton decay was dominated
not by the classical curvaton field but by the curvaton particles produced
during reheating. We describe the curvaton-inflaton transmutation effect: The
same field in different parts of the universe may play either the role of the
curvaton or the role of the inflaton. Finally, we discuss an interplay between
the curvaton web and anthropic considerations in the string theory landscape.


title:
Nature and completeness of galaxies detected in the Two Micron All Sky
  Survey

abstract:
  We cross correlate the well-defined and very complete spectroscopic Main
Galaxy Sample (MGS) of 156,000 bright (r<17.5 mag) galaxies from the SDSS with
2MASS sources to explore the nature and completeness of the 2MASS K-band
selection of nearby galaxies. 2MASS detects 90% of the MGS brighter than r=17
mag. For r<16, 93.1% of the MGS is found in the 2MASS Extended Source Catalog
(XSC). These detections span the representative range of optical and near-IR
galaxy properties, but with a surface brightness-dependent bias to
preferentially miss the most blue and low-concentration sources, consistent
with the most morphologically late-type galaxy population. An XSC completeness
of 97.5% is achievable at bright magnitudes, with blue LSBs being the only
major source of incompleteness, if one follows our careful matching criteria
and weeds out spurious SDSS sources. We conclude that the rapid drop in XSC
completeness at r>16 reflects the sharp surface-brightness limit of the
extended source detection algorithm in 2MASS. As a result, the r>16 galaxies
found in the XSC are over-representative in red early types and
under-representative in blue latetypes. At r>16 the XSC suffers an additional
selection effect from the 2-3" spatial resolution limit of 2MASS. Therefore,
2MASS continues to detect 90% of of the MGS at 16<r<17, but with a growing
fraction found in the Point Source Catalog (PSC) only. Overall, one third of
the MGS is detected in the 2MASS PSC but not the XSC. A combined K<13.57 and
r<16 selection provides the most representative inventory of galaxies in the
local cosmos with near-IR and optical measurements, and 90.8% completeness.
Using data from SDSS-DR2, this sample contains 19,156 galaxies with a median
redshift of 0.052. (abridged)


title:
Equilibrium of large astrophysical structures in the Newton-Hooke
  spacetime

abstract:
  Using the scalar and tensor virial equations, the Lane-Emden equation
expressing the hydrostatic equilibrium and small oscillations around the
equilibrium, we show how the cosmological constant $\Lambda$ affects various
astrophysical quantities important for large matter conglomeration in the
universe. Among others we examine the effect of $\Lambda$ on the polytropic
equation of state for spherically symmetric objects and find non-negligible
results in certain realistic cases. We calculate the angular velocity for
non-spherical oblate configurations which demonstrates a clear effect of
$\Lambda$ on high eccentricity objects. We show that for oblate as well as
prolate ellipsoids the cosmological constant influences the critical mass and
the temperature of the astrophysical object. These and other results show that
the effect of $\Lambda$ is large for flat astrophysical bodies.


title: Angular Momentum Transport by Gravity Waves in the Solar Interior

abstract:
  We present self-consistent numerical simulations of the sun's convection zone
and radiative interior using a two-dimensional model of its equatorial plane.
The background reference state is a one-dimensional solar structure model.
Turbulent convection in the outer convection zone continually excites gravity
waves which propagate throughout the stable radiative interior and deposit
their angular momentum. We find that angular velocity variations in the
tachocline are driven by angular momentum transported by overshooting
convective plumes rather than the nonlinear interaction of waves. The mean flow
in the tachocline is time dependent but not oscillatory in direction. Since the
forcing in this shallow region can not be described by simple linear waves, it
is unlikely that the interaction of such waves is responsible for the solar
cycle or the 1.3 year oscillation. However, in the deep radiative interior, the
interaction of low amplitude gravity waves, continually excited by the
overshooting plumes, is responsible for the angular velocity deviations
observed there. Near the center of the model sun the angular velocity deviation
is about two orders of magnitude greater than that in the bulk of the radiative
region and reverses its direction (prograde to retrograde or vice versa) in the
opposite sense of the angular velocity deviations that occur in the tachocline.
Our simulations thus demonstrate how angular velocity variations in the solar
core are linked to those in the tachocline, which themselves are driven by
convective overshooting.


title:
Thermal effects on the absorption of ultra-high energy neutrinos by the
  cosmic neutrino background

abstract:
  We use the formalism of finite-temperature field theory to study the
interactions of ultra-high energy (UHE) cosmic neutrinos with the background of
relic neutrinos and to derive general expressions for the UHE neutrino
transmission probability. This approach allows us to take into account the
thermal effects introduced by the momentum distribution of the relic neutrinos.
We compare our results with the approximate expressions existing in the
literature and discuss the influence of thermal effects on the absorption dips
in the context of favoured neutrino mass schemes, as well as in the case of
clustered relic neutrinos.


title:
Hi-Res Spectroscopy of a Volume-Limited Hipparcos Sample within 100
  parsec: Austin Bash Symposium Conference Proceeding

abstract:
  Accurate parallaxes from the Hipparcos catalog have enabled detailed studies
of stellar properties. Subgiants are of particular interest because they lie in
an area where isochrones are well separated, enabling dependable age
determination. We have initiated a project to obtain hi-res spectra of
Hipparcos subgiants in a volume-limited sample within 100 pc. We obtain stellar
properties and abundances via fully automatic analysis. We will use our results
to constrain star formation history and chemical evolution in the solar
neighborhood. We present initial results for our observed sample and discuss
future development for this project.


title: Dark world and baryon asymmetry from a common source

abstract:
  We study generation of baryon number asymmetry and both abundance of dark
matter and dark energy on the basis of global symmetry and its associating flat
directions in a supersymmetric model. We assume the existence of a model
independent axion which is generally expected in the effective theory of
superstring. If we consider a combined field of the model independent axion and
a pseudo Nambu-Goldstone boson coming from spontaneous breaking of the global
symmetry, its potential can be sufficiently flat and then it may present a
candidate of the dark energy as a quintessential axion. Both the baryon
asymmetry and the dark matter are supposed to be produced nonthermally as the
asymmetry of another global charge through the Affleck-Dine mechanism along the
relevant flat direction. Its decay to the observable and hidden sectors
explains the baryon number asymmetry and the dark matter abundance,
respectively.


title: Primordial Black Holes: Do They Exist and Are They Useful?

abstract:
  Recent developments in the study of primordial black holes (PBHs) are
reviewed, with particular emphasis on their formation and evaporation. It is
still not clear whether PBHs formed but, if they did, they could provide a
unique probe of the early Universe, gravitational collapse, high energy physics
and quantum gravity. Indeed their study may place interesting constraints on
the physics relevant to these areas even if they never existed.


title:
Stellar model atmospheres with magnetic line blanketing. II.
  Introduction of polarized radiative transfer

abstract:
  The technique of model atmosphere calculation for magnetic Ap and Bp stars
with polarized radiative transfer and magnetic line blanketing is presented. A
grid of model atmospheres of A and B stars are computed. These calculations are
based on direct treatment of the opacities due to the bound-bound transitions
that ensures an accurate and detailed description of the line absorption and
anomalous Zeeman splitting. The set of model atmospheres was calculated for the
field strengths between 1 and 40 kG. The high-resolution energy distribution,
photometric colors and the hydrogen Balmer line profiles are computed for
magnetic stars with different metallicities and are compared to those of
non-magnetic reference models and to the previous paper of this series. The
results of modelling confirmed the main outcomes of the previous study: energy
redistribution from UV to the visual region and flux depression at 5200A.
However, we found that effects of enhanced line blanketing when transfer for
polarized radiation takes place are smaller in comparison to those obtained in
our first paper where polarized radiative transfer was neglected. Also we found
that the peculiar photometric parameter delta_a is not able to clearly
distinguish stellar atmospheres with abundances other than solar, and is less
sensitive than delta(V_1-G) or Z to a magnetic field for low effective
temperature (Teff=8000K). Moreover we found that the back determination of the
fundamental stellar atmosphere parameters using synthetic Stromgren photometry
does not result in significant errors.


title:
Dark Energy: relating the evolution of the universe from the past to the
  future

abstract:
  Using the evolution history of the universe, one can make constraint on the
parameter space of dynamic dark energy models. We discuss two different
parameterized dark energy models. Our results further restrict the combined
constraints obtained from supernova and WMAP observations. From the allowed
parameter space, it is found that our universe will experience an eternal
acceleration. We also estimate the bound on the physically relevant regions
both in the re-inflationary and inflationary phases.


title: Weak lensing mass reconstructions of the ESO Distant Cluster Survey

abstract:
  We present weak lensing mass reconstructions for the 20 high-redshift
clusters i n the ESO Distant Cluster Survey. The weak lensing analysis was
performed on deep, 3-color optical images taken with VLT/FORS2, using a
composite galaxy catalog with separate shape estimators measured in each
passband. We find that the EDisCS sample is composed primarily of clusters that
are less massive than t hose in current X-ray selected samples at similar
redshifts, but that all of the fields are likely to contain massive clusters
rather than superpositions of low mass groups. We find that 7 of the 20 fields
have additional massive structures which are not associated with the clusters
and which can affect the weak lensing mass determination. We compare the mass
measurements of the remaining 13 clusters with luminosity measurements from
cluster galaxies selected using photometric redshifts and find evidence of a
dependence of the cluster mass-to-light ratio with redshift. Finally we
determine the noise level in the shear measurements for the fields as a
function of exposure time and seeing and demonstrate that future ground-based
surveys which plan to perform deep optical imaging for use in weak lensing
measurements must achieve point-spread functions smaller than a median of 0.6"
FWHM.


title:
The nature of X-ray absorbed starburst QSOs and the QSO evolutionary
  scheme

abstract:
  In contradiction to the simple AGN unification schemes, there exists a
significant population of broad line, z~2 QSOs which have heavily absorbed
X-ray spectra. These objects have luminosities and redshifts characteristic of
the sources that produce the bulk of the QSO luminosity in the universe. Our
follow up observations in the submillimetre show that these QSOs are embedded
in ultraluminous starburst galaxies, unlike most unabsorbed QSOs at the same
redshifts and luminosities. The radically different star formation properties
between the absorbed and unabsorbed QSOs implies that the X-ray absorption is
unrelated to the torus invoked in AGN unification schemes. The most puzzling
question about these objects is the nature of the X-ray absorber. We present
our study of the X-ray absorbers based on deep (50-100ks) XMM-Newton
spectroscopy. The hypothesis of a normal QSO continuum, coupled with a neutral
absorber is strongly rejected. We consider the alternative hypotheses for the
absorber, originating either in the QSO or in the surrounding starburst.
Finally we discuss the implications for QSO/host galaxy formation, in terms of
an evolutionary sequence of star formation and black hole growth. We propose
that both processes occur simultaneously in the gas-and-dust-rich heavily
obscured centres of young galaxies, and that absorbed QSOs form a transitional
stage, between the main obscured growth phase, and the luminous QSO.


abstract:
  We present XMM-Newton observations of the Seyfert 1 AGN H0557-385. We have
conducted a study into the warm absorber present in this source, and using
high-resolution RGS data we find that the absorption can be characterised by
two phases: a phase with log ionisation parameter xi of 0.50 (where xi is in
units of ergs cm/s) and a column of 0.2e21 cm^-2, and a phase with log xi of
1.62 and a column of 1.3e22 cm^-2. An iron K alpha line is detected. Neutral
absorption is also present in the source, and we discuss possible origins for
this. On the assumption that the ionised absorbers originate as an outflow from
the inner edge of the torus, we use a new method for finding the volume filling
factor. Both phases of H0557-385 have small volume filling factors (< 1%). We
also derive the volume filling factors for a sample of 23 AGN using this
assumption and for the absorbers with log xi > 0.7 we find reasonable agreement
with the filling factors obtained through the alternative method of equating
the momentum flow of the absorbers to the momentum loss of the radiation field.
By comparing the filling factors obtained by the two methods, we infer that
some absorbers with log xi < 0.7 occur at significantly larger distances from
the nucleus than the inner edge of the torus.


title:
Efficiency Crisis of Swift Gamma-Ray Bursts with Shallow X-ray
  Afterglows: Prior Activity or Time-Dependent Microphysics?

abstract:
  Most X-ray afterglows of gamma-ray bursts (GRBs) observed by the Swift
satellite have a shallow decay phase t^{-1/2} in the first few hours. This is
not predicted by the standard afterglow model and needs an explanation. We
discuss that the shallow decay requires an unreasonably high gamma-ray
efficiency, >75-90%, within current models, which is difficult to produce by
internal shocks. Such a crisis may be avoided if a weak relativistic explosion
occurs ~10^3-10^6 s prior to the main burst or if the microphysical parameter
of the electron energy increases during the shallow decay, \epsilon_e ~
t^{1/2}. The former explanation predicts a very long precursor, while both
prefer dim optical flashes from the reverse shock, as was recently reported. We
also calculate the multi-wavelength afterglows and compare them with
observations. No optical break at the end of the shallow X-ray decay indicates
a preference for the time-dependent microphysics model with additionally
decaying magnetic fields, \epsilon_B ~ t^{-0.6}.


title: Evidence for intrinsic absorption in the Swift X-ray afterglows

abstract:
  Gamma-ray burst (GRB) progenitors are observationally linked to the death of
massive stars. X-ray studies of the GRB afterglows can deepen our knowledge of
the ionization status and metal abundances of the matter in the GRB
environment. Moreover, the presence of local matter can be inferred through its
fingerprints in the X-ray spectrum, i.e. the presence of absorption higher than
the Galactic value. A few studies based on BeppoSAX and XMM-Newton found
evidence of higher than Galactic values for the column density in a number of
GRB afterglows. Here we report on a systematic analysis of 17 GRBs observed by
Swift up to April 15, 2005. We observed a large number of GRBs with an excess
of column density. Our sample, together with previous determinations of the
intrinsic column densities for GRBs with known redshift, provides evidence for
a distribution of absorption consistent with that predicted for randomly
occurring GRB within molecular clouds.