title: A Chandra Catalog of X-ray Sources in the Central 150 pc of the Galaxy

abstract:
  We present the catalog of X-ray sources detected in a shallow Chandra survey
of the inner 2 by 0.8 degrees of the Galaxy, and in two deeper observations of
the Radio Arches and Sgr B2. The catalog contains 1352 objects that are
highly-absorbed (N_H > 4e22 cm^-2 and are therefore likely to lie near the
Galactic center (D~8 kpc), and 549 less-absorbed sources that lie within <6 kc
of Earth. Based on the inferred luminosities of the X-ray sources and the
expected numbers of various classes of objects, we suggest that the sources
with L_X < 1e33 erg/s that comprise ~90% of the catalog are cataclysmic
variables, and that the ~100 brighter objects are accreting neutron stars and
black holes, young isolated pulsars, and Wolf-Rayet and O stars in
colliding-wind binaries. We find that the spatial distribution of X-ray sources
matches that of the old stellar population observed in the infrared, which
supports our suggestion that most of the X-ray sources are old cataclysmic
variables. However, we find that there is an apparent excess of ~10 bright
sources in the Radio Arches region. That region is already known to be the site
of recent star formation, so we suggest that the bright sources in this region
are young high-mass X-ray binaries, pulsars, or WR/O star binaries. We briefly
discuss some astrophysical questions that this catalog can be used to address.


title:
The Sloan Lens ACS Survey. III - The Structure and Formation of
  Early-type Galaxies and their Evolution since z~1

abstract:
  (Abridged) We present a joint gravitational lensing and stellar dynamical
analysis of fifteen massive field early-type galaxies, selected from the Sloan
Lens (SLACS) Survey. The following numerical results are found: (i) A
joint-likelihood gives an average logarithmic density slope for the total mass
density of 2.01 (+0.02/-0.03) (68 perecnt C.L). inside the Einstein radius.
(ii) The average position-angle difference between the light distribution and
the total mass distribution is found to be 0+-3 degrees, setting an upper limit
of <= 0.035 on the average external shear. (iii) The average projected
dark-matter mass fraction is inferred to be 0.25+-0.06 inside R_E, using the
stellar mass-to-light ratios derived from the Fundamental Plane as priors. (iv)
Combined with results from the LSD Survey, we find no significant evolution of
the total density slope inside one effective radius: a linear fit gives
d\gamma'/dz = 0.23+-0.16 (1-sigma) for the range z=0.08-1.01. The small scatter
and absence of significant evolution in the inner density slopes suggest a
collisional scenario where gas and dark matter strongly couple during galaxy
formation, leading to a total mass distribution that rapidly converge to
dynamical isothermality.


title:
Low radiative efficiency accretion at work in active galactic nuclei:
  the nuclear spectral energy distribution of NGC4565

abstract:
  We derive the spectral energy distribution (SED) of the nucleus of the
Seyfert galaxy NGC4565. Despite its classification as a Seyfert2, the nuclear
source is substantially unabsorbed. The absorption we find from Chandra data
(N_H=2.5 X 10^21 cm^-2) is consistent with that produced by material in the
galactic disk of the host galaxy. HST images show a nuclear unresolved source
in all of the available observations, from the near-IR H band to the optical U
band. The SED is completely different from that of Seyfert galaxies and QSO, as
it appears basically ``flat'' in the IR-optical region, with a small drop-off
in the U-band. The location of the object in diagnostic planes for low
luminosity AGNs excludes a jet origin for the optical nucleus, and its
extremely low Eddington ratio L_o/L_Edd indicates that the radiation we observe
is most likely produced in a radiatively inefficient accretion flow (RIAF).
This would make NGC4565 the first AGN in which an ADAF-like process is
identified in the optical. We find that the relatively high [OIII] flux
observed from the ground cannot be all produced in the nucleus. Therefore, an
extended NLR must exist in this object. This may be interpreted in the
framework of two different scenarios: i) the radiation from ADAFs is sufficient
to give rise to high ionization emission-line regions through photoionization,
or ii) the nuclear source has recently ``turned-off'', switching from a
high-efficiency accretion regime to the present low-efficiency state.


title: Hosts of Type II Quasars: an HST Study

abstract:
  Type II quasars are luminous Active Galactic Nuclei whose centers are
obscured by large amounts of gas and dust. In this contribution we present
3-band HST images of nine type II quasars with redshifts 0.25<z<0.4 selected
from the Sloan Digital Sky Survey based on their emission line properties. The
intrinsic luminosities of these quasars are thought to be in the range
-24>M_B>-26, but optical obscuration implies that host galaxies can be studied
unencumbered by bright nuclei. Each object has been imaged in three filters
(`red', `green' and `blue') placed between the strong emission lines. The
spectacular, high quality images reveal a wealth of details about the structure
of the host galaxies and their environments. Most galaxies in the sample are
ellipticals, but strong deviations from de Vaucouleurs profiles are found,
especially in the blue band. We argue that most of these deviations are due to
the light from the nucleus scattered off interstellar material in the host
galaxy. This scattered component can make a significant contribution to the
broad-band flux and complicates the analysis of the colors of the stellar
populations in the host galaxy. This extended component can be difficult to
notice in unobscured luminous quasars and may bias the results of host galaxy
studies.


title:
On the feedback from super stellar clusters. I. The structure of giant
  HII regions and HII galaxies

abstract:
  We review the structural properties of giant extragalactic HII regions and
HII galaxies based on 2D hydrodynamic calculations, and propose an evolutionary
sequence that accounts for their observed detailed structure. The model assumes
a massive and young stellar cluster surrounded by a large collection of clouds.
These are thus exposed to the most important star-formation feedback
mechanisms: photoionization and the cluster wind. The models show how the two
feedback mechanisms compete in the disruption of clouds and lead to two
different hydrodynamic solutions: The storage of clouds into a long lasting
ragged shell that inhibits the expansion of the thermalized wind, and the
steady filtering of the shocked wind gas through channels carved within the
cloud stratum. Both solutions are claimed to be concurrently at work in giant
HII regions and HII galaxies, causing their detailed inner structure. This
includes multiple large-scale shells, filled with an X-ray emitting gas, that
evolve to finally merge with each other, giving the appearance of shells within
shells. The models also show how the inner filamentary structure of the giant
superbubbles is largely enhanced with matter ablated from clouds and how cloud
ablation proceeds within the original cloud stratum. The calculations point at
the initial contrast density between the cloud and the intercloud media as the
factor that defines which of the two feedback mechanisms becomes dominant
throughout the evolution. Animated version of the models can be found at
http://www.iaa.csic.es/\~{}eperez/ssc/ssc.html.


title:
Observations of Magnetic Fields and Relativistic Beaming in Four Quasar
  Jets

abstract:
  We discuss the physical properties of four quasar jets imaged with the
Chandra X-ray Observatory in the course of a survey for X-ray emission from
radio jets. These objects have sufficient counts to study their spatially
resolved properties, even in the 5 ks survey observations. We have acquired
Australia Telescope Compact Array data with resolution matching Chandra. We
have searched for optical emission with Magellan, with sub-arcsecond
resolution. The radio to X-ray spectral energy distribution for most of the
individual regions indicates against synchrotron radiation from a
single-component electron spectrum. We therefore explore the consequences of
assuming that the X-ray emission is the result of inverse Compton scattering on
the cosmic microwave background. If particles and magnetic fields are near
minimum energy density in the jet rest frames, then the emitting regions must
be relativistically beamed, even at distances of order 500 kpc from the quasar.
We estimate the magnetic field strengths, relativistic Doppler factors, and
kinetic energy flux as a function of distance from the quasar core for two or
three distinct regions along each jet. We develop, for the first time,
estimates in the uncertainties in these parameters, recognizing that they are
dominated by our assumptions in applying the standard synchrotron minimum
energy conditions. The kinetic power is comparable with, or exceeds, the quasar
radiative luminosity, implying that the jets are a significant factor in the
energetics of the accretion process powering the central black hole. The
measured radiative efficiencies of the jets are of order 10^(-4).


title:
Spectacular Spitzer images of the Trifid Nebula: Protostars in a young,
  massive-star-forming region

abstract:
  Spitzer IRAC and MIPS images of the Trifid Nebula (M20) reveal its
spectacular appearance in infrared light, highlighting the nebula's special
evolutionary stage. The images feature recently-formed massive protostars and
numerous young stellar objects, and a single O star that illuminates the
surrounding molecular cloud from which it formed, and unveil large-scale,
filamentary dark clouds. The hot dust grains show contrasting infrared colors
in shells, arcs, bow-shocks and dark cores. Multiple protostars are detected in
the infrared, within the cold dust cores of TC3 and TC4, which were previously
defined as Class 0. The cold dust continuum cores of TC1 and TC2 contain only
one protostar each. The Spitzer color-color diagram allowed us to identify ~160
young stellar objects and classify them into different evolutionary stages. The
diagram also revealed a unique group of YSOs which are bright at 24 micron but
have the spectral energy distribution peaking at 5-8 micron. Despite
expectation that Class 0 sources would be "starless" cores, the Spitzer images,
with unprecedented sensitivity, uncover mid-infrared emission from these Class
0 protostars. The mid-infrared detections of Class 0 protostars show that the
emission escapes the dense, cold envelope of young protostars. The mid-infrared
emission of the protostars can be fit by two temperatures of 150 and 400 K; the
hot core region is probably optically thin in the mid-infrared regime, and the
size of hot core is much smaller than that of the cold envelope. The presence
of multiple protostars within the cold cores of Class 0 objects implies that
clustering occurs at this early stage of star formation. The TC3 cluster shows
that the most massive star is located at the center of the cluster and at the
bottom of the gravitational-potential well.


title:
Spatial Correlation Function of the Chandra Selected Active Galactic
  Nuclei

abstract:
  We present the spatial correlation function analysis of non-stellar X-ray
point sources in the Chandra Large Area Synoptic X-ray Survey of Lockman Hole
Northwest (CLASXS). Our 9 ACIS-I fields cover a contiguous solid angle of 0.4
deg^2 and reach a depth of 3x10^-15 c.g.s in the 2-8 keV band. We supplement
our analysis with data from the Chandra Deep Field North (CDFN). The addition
of this field allows better probe of the correlation function at small scales.
A total of 233 and 252 sources with spectroscopic information are used in the
study of the CLASXS and CDFN fields respectively. We calculate both
redshift-space and projected correlation functions in comoving coordinates,
averaged over the redshift range of 0.1<z<3.0, for both CLASXS and CDFN fields
for a standard cosmology with \Omega_{\Lambda} = 0.73, \Omega_{M} = 0.27, and
H_0 = 0.71. The correlation function for the CLASXS field over scales of 3 Mpc
<s< 200 Mpc can be modeled as a power-law of the form \xi(s) =
(s/s_0)^{-\gamma}, with \gamma = 1.6^{+0.4}_{-0.3} and s_0 = 8.0^{+1.4}_{-1.5}
Mpc. The redshift-space correlation function for CDFN on scales of 1
Mpc$<s<$~100 Mpc is found to have a similar correlation length $s_0 =
8.55^{+0.75}_{-0.74}$ Mpc, but a shallower slope ($\gamma = 1.3 \pm 0.1$). The
real-space correlation functions derived from the projected correlation
functions, are found to be $r_0 = 8.1^{+1.2}_{-2.2}$ Mpc, and $\gamma = 2.1 \pm
0.5$ for the CLASXS field, and $r_0 = 5.8^{+1.0}_{-1.5}$ Mpc, $\gamma =
1.38^{+0.12}_{-0.14}$ for the CDFN field. By comparing the real- and
redshift-space correlation functions in the combined CLASXS and CDFN samples,
we are able to estimate the redshift distortion parameter $\beta = 0.4 \pm 0.2$
at an effective redshift $z = 0.94$.(abridged)


title:
Equations of General Relativistic Radiation Hydrodynamics from Tensor
  Formalism

abstract:
  Radiation interacts with matter via exchange of energy and momentum. When
matter is moving with a relativistic velocity or when the background spacetime
is strongly curved, rigorous relativistic treatment of hydrodynamics and
radiative transfer is required. Here, we derive fully general relativistic
radiation hydrodynamic equations from a covariant tensor formalism. The
equations can be applied to any three-dimensional problems and are rather
starightforward to understand compared to the comoving frame-based equations.
Current approach is applicable to any spacetime or coordinates, but in this
work we specifically choose the Schwarzschild spacetime to show explicitly how
the hydrodynamic and the radiation moment equations are derived. Some important
aspects of relativistic radiation hydrodynamics and the difficulty with the
radiation moment formalism are discussed as well.


title:
First Attempt at Spectroscopic Detection of Gravity Modes in a
  Long-Period Pulsating Subdwarf B Star -- PG 1627+017

abstract:
  In the first spectroscopic campaign for a PG 1716 variable (or long-period
pulsating subdwarf B star), we succeeded in detecting velocity variations due
to g-mode pulsations at a level of 1.0-1.5 km/s.The observations were obtained
during 40 nights on 2-m class telescopes in Arizona, South Africa,and
Australia. The target,PG1627+017, is one of the brightest and largest amplitude
stars in its class.It is also the visible component of a post-common envelope
binary.Our final radial velocity data set includes 84 hours of time-series
spectroscopy over a time baseline of 53 days. Our derived radial velocity
amplitude spectrum, after subtracting the orbital motion, shows three potential
pulsational modes 3-4 sigma above the mean noise level, at 7201.0s,7014.6s and
7037.3s.Only one of the features is statistically likely to be real,but all
three are tantalizingly close to, or a one day alias of, the three strongest
periodicities found in the concurrent photometric campaign. We further
attempted to detect pulsational variations in the Balmer line amplitudes. The
single detected periodicity of 7209 s, although weak, is consistent with
theoretical expectations as a function of wavelength.Furthermore, it allows us
to rule out a degree index of l= 3 or l= 5 for that mode. Given the extreme
weakness of g-mode pulsations in these stars,we conclude that anything beyond
simply detecting their presence will require larger telescopes,higher
efficiency spectral monitoring over longer time baselines,improved longitude
coverage, and increased radial velocity precision.


title: ELT requirements for future observations of the Intergalactic Medium

abstract:
  We summarise the science cases for an ELT that were presented in the parallel
session on the intergalactic medium, and the open discussion that followed the
formal presentations. Observations of the IGM with an ELT provides tremendous
potential for dramatic improvements in current programmes in a very wide
variety of subjects. These range from fundamental physics (expansion of the
Universe, nature of the dark matter, variation of physical constants),
cosmology (geometry of the Universe, large-scale structure), reionisation
(ionisation state of the IGM at high redshift>6, to more traditional astronomy,
such as the interactions between galaxies and the IGM (metal enrichment,
galactic winds and other forms of feedback), and the study of the interstellar
medium in high redshift galaxies through molecules. The requirements on ELTs
and their instruments for fulfilling this potential are discussed.


title: Tracing the Mass-Assembly History of Galaxies with Deep Surveys

abstract:
  We use the optical and near-infrared galaxy samples from the Munich
Near-Infrared Cluster Survey (MUNICS), the FORS Deep Field (FDF) and GOODS-S to
probe the stellar mass assembly history of field galaxies out to z ~ 5.
Combining information on the galaxies' stellar mass with their star-formation
rate and the age of the stellar population, we can draw important conclusions
on the assembly of the most massive galaxies in the universe: These objects
contain the oldest stellar populations at all redshifts probed. Furthermore, we
show that with increasing redshift the contribution of star-formation to the
mass assembly for massive galaxies increases dramatically, reaching the era of
their formation at z ~ 2 and beyond. These findings can be interpreted as
evidence for an early epoch of star formation in the most massive galaxies in
the universe.


title: The stellar populations of E and S0 galaxies as seen with SAURON

abstract:
  We present selected results from integral-field spectroscopy of 48 early-type
galaxies observed as part of the SAURON survey. Maps of the Hbeta, Fe5015, Mgb
and Fe5270 indices in the Lick/IDS system were derived for each of the survey
galaxies. The metal line strength maps show generally negative gradients with
increasing radius roughly consistent with the morphology of the light profiles.
Remarkable deviations from this general trend exist, particularly the Mgb
isoindex contours appear to be flatter than the isophotes of the surface
brightness for about 40% of our galaxies without significant dust features.
Generally these galaxies exhibit significant rotation. We infer from this that
the fast-rotating component features a higher metallicity and/or an increased
Mg/Fe ratio as compared to the galaxy as a whole. We also use the line
strengths maps to compute average values integrated over circular apertures of
one effective radius, and derive luminosity weighted ages and metallicities.
The lenticular galaxies show a wide range in age and metallicity estimates,
while elliptical galaxies tend to occupy regions of older stellar populations.


title: An HLLC Solver for Relativistic Flows -- II. Magnetohydrodynamics

abstract:
  An approximate Riemann solver for the equations of relativistic
magnetohydrodynamics (RMHD) is derived. The HLLC solver, originally developed
by Toro, Spruce and Spears, generalizes the algorithm described in a previous
paper (Mignone & Bodo 2004) to the case where magnetic fields are present. The
solution to the Riemann problem is approximated by two constant states bounded
by two fast shocks and separated by a tangential wave. The scheme is
Jacobian-free, in the sense that it avoids the expensive characteristic
decomposition of the RMHD equations and it improves over the HLL scheme by
restoring the missing contact wave.
  Multidimensional integration proceeds via the single step, corner transport
upwind (CTU) method of Colella, combined with the contrained tranport (CT)
algorithm to preserve divergence-free magnetic fields. The resulting numerical
scheme is simple to implement, efficient and suitable for a general equation of
state. The robustness of the new algorithm is validated against one and two
dimensional numerical test problems.


title: INTEGRAL observations of the Crab pulsar

abstract:
  The paper presents the timing and spectral analysis of several observations
of the Crab pulsar performed with INTEGRAL in the energy range 3-500 keV. All
these observations, when summed together provide a high statistics data set
which can be used for accurate phase resolved spectroscopy. A detailed study of
the pulsed emission at different phase intervals is performed. The spectral
distribution changes with phase showing a characteristic reverse S shape of the
photon index. Moreover the spectrum softens with energy, in each phase
interval, and this behavior is adequately modeled over the whole energy range
3-500 keV with a single curved law with a slope variable with Log(E),
confirming the BeppoSAX results on the curvature of the pulsed emission. The
bending parameter of the log-parabolic model is compatible with a single value
of 0.14+/-0.02 over all phase intervals. Results are discussed within the
three-dimensional outer gap model.


title: Smoothed Particle Hydrodynamics coupled with Radiation Transfer

abstract:
  We have been constructed a brand-new radiation hydrodynamics solver based
upon Smoothed Particle Hydrodynamics (SPH), which works on parallel computer
system. The code is designed to investigate the formation and evolution of the
first generation objects at $z \gtrsim 10$, where the radiative feedback from
various sources play important roles. The code can compute the fraction of
chemical species e, H$^+$, H,
  H$^-$, H$_2$, and H$_2^+$ by fully implicit time integration. It also can
deal with multiple sources of ionizing radiation, as well as the radiation at
Lyman-Werner band. We compare the results for a few test calculations with the
results of one dimensional simulations, in which we find good agreements with
each other.
  We also evaluate the speedup by parallelization, that is found to be almost
ideal, as far as the number of sources is comparable to the number of
processors.


title:
Radial velocity measurements of B stars in the Scorpius-Centaurus
  association

abstract:
  We derive single-epoch radial velocities for a sample of 56 B-type stars
members of the subgroups Upper Scorpius, Upper Centaurus Lupus and Lower
Centaurus Crux of the nearby Sco-Cen OB association. The radial velocity
measurements were obtained by means of high-resolution echelle spectra via
analysis of individual lines. The internal accuracy obtained in the
measurements is estimated to be typically 2-3 km/s, but depends on the
projected rotational velocity of the target. Radial velocity measurements taken
for 2-3 epochs for the targets HD120307, HD142990 and HD139365 are variable and
confirm that they are spectroscopic binaries, as previously identified in the
literature. Spectral lines from two stellar components are resolved in the
observed spectra of target stars HD133242, HD133955 and HD143018, identifying
them as spectroscopic binaries.


title: INTEGRAL survey of the Cassiopeia region in hard X rays

abstract:
  We report on the results of a deep 1.6 Ms INTEGRAL observation of the
Cassiopeia region performed from December 2003 to February 2004. Eleven sources
were detected with the imager IBIS-ISGRI at energies above 20 keV, including
three new hard X-ray sources. Most remarkable is the discovery of hard X-ray
emission from the anomalous X-ray pulsar 4U 0142+61, which shows emission up to
\~150 keV with a very hard power-law spectrum with photon index Gamma = 0.73
+/- 0.17. We derived flux upper limits for energies between 0.75 MeV and 30 MeV
using archival data from the Compton telescope COMPTEL. In order to reconcile
the very hard spectrum of 4U 0142+61 measured by INTEGRAL with the COMPTEL
upper limits, the spectrum has to bend or break between ~75 keV and ~750 keV.
1E 2259+586, another anomalous X-ray pulsar in this region, was not detected.
INTEGRAL and COMPTEL upper limits are provided. The new INTEGRAL sources are
IGR J00370+6122 and IGR J00234+6144. IGR J00370+6122 is a new supergiant X-ray
binary with an orbital period of 15.665 +/- 0.006 days, derived from RXTE
All-Sky Monitor data. Archival BeppoSAX Wide-Field Camera data yielded four
more detections. IGR J00234+6144 still requires a proper identification. Other
sources for which INTEGRAL results are presented are high-mass X-ray binaries
2S 0114+650, Gamma~Cas, RX J0146.9+6121 and 4U 2206+54, intermediate polar V709
Cas and 1ES 0033+595, an AGN of the BL-Lac type. For each of these sources the
hard X-ray spectra are fitted with different models and compared with earlier
published results.


title:
The Uncertainties in the 22Ne + alpha-capture Reaction Rates and the
  Production of the Heavy Magnesium Isotopes in Asymptotic Giant Branch Stars
  of Intermediate Mass

abstract:
  We present new rates for the 22Ne(alpha, n)25Mg and 22Ne(alpha,gamma)26Mg
reactions, with uncertainties that have been considerably reduced compared to
previous estimates, and we study how these new rates affect the production of
the heavy magnesium isotopes in models of intermediate mass Asymptotic Giant
Branch (AGB) stars of different initial compositions. All the models have deep
third dredge-up, hot bottom burning and mass loss. Calculations have been
performed using the two most commonly used estimates of the 22Ne + alpha rates
as well as the new recommended rates, and with combinations of their upper and
lower limits. The main result of the present study is that with the new rates,
uncertainties on the production of isotopes from Mg to P coming from the 22Ne +
alpha-capture rates have been considerably reduced. We have therefore removed
one of the important sources of uncertainty to effect models of AGB stars. We
have studied the effects of varying the mass-loss rate on nucleosynthesis and
discuss other uncertainties related to the physics employed in the computation
of stellar structure, such as the modeling of convection, the inclusion of a
partial mixing zone and the definition of convective borders. These
uncertainties are found to be much larger than those coming from 22Ne +
alpha-capture rates, when using our new estimates. Much effort is needed to
improve the situation for AGB models.


title: On the Decoherence of Primordial Fluctuations During Inflation

abstract:
  We study the process whereby quantum cosmological perturbations become
classical within inflationary cosmology. By setting up a master-equation
formulation we show how quantum coherence for super-Hubble modes can be
destroyed by their coupling to the environment provided by sub-Hubble modes. We
identify what features the sub-Hubble environment must have in order to
decohere the longer wavelengths, and identify how the onset of decoherence (and
how long it takes) depends on the properties of the sub-Hubble physics which
forms the environment. Our results show that the decoherence process is largely
insensitive to the details of the coupling between the sub- and super-Hubble
scales. They also show how locality implies, quite generally, that the
decohered density matrix at late times is diagonal in the field representation
(as is implicitly assumed by extant calculations of inflationary density
perturbations). Our calculations also imply that decoherence can arise even for
couplings which are as weak as gravitational in strength.


title:
Search for and investigation of new stellar clusters using the data from
  huge stellar catalogues

abstract:
  We present new automatic methods of search for star clusters using the data
available in new huge stellar catalogues. Using 2MASS catalogue we have
discovered over ten new open clusters in the region of Galaxy anticenter and
determined their physical parameters.


title: Dynamical Evolution of the TW Hya Association

abstract:
  Using Galactic dynamics we have determined the age of the low mass post-T
Tauri stars TW Hya Association (TWA). To do so we applied the method of Ortega
et al.(2002, 2004) to five stars of the association with Hipparcos measured
distances (TWA 1, TWA 4,TWA 9,TWA 11,TWA 19).The method is based on the
calculation of the past 3D orbits of the stars. Of these stars only TWA 9
presents a quite different orbit so that it does not appear to be a dynamical
member of TWA. The four remaining stars have a first maximum orbits'
confinement at the age of -8.3 $\pm{0.8}$ Myr which is considered the dynamical
age of TWA. This confinement fixes the probable 3D forming region of TWA with a
mean radius of 14.5 pc. This region is related to the older subgroups of the
Sco-Cen OB association, Lower Centaurus Crux (LCC) and Upper Centaurus Lupus
(UCL), both with a mean age of about 18 Myr. This dynamical age of TWA and that
of the $\beta$ Pic Moving Group (BPMG) with an age of 11 Myr, also discussed
here, introduce a more precise temporal scale for studies of disks evolution
and planetary formation around some stars of these associations. Using the
retraced orbit of the runaway star HIP 82868 we examine the possibility that
the formation of TWA was triggered by a supernova (SN) explosion. It is shown
that for the four considered TWA stars, the expansion in volume is a factor of
five since their origin to the present state. This is mainly due to the
presently more distant star TWA 19.


title: Near-infrared observations of water-ice in OH/IR stars

abstract:
  A search for the near-infrared water-ice absorption band was made in a number
of very red OH/IR stars which are known to exhibit the 10um silicate
absorption. As a by-product, accurate positions of these highly reddened
objects are obtained. We derived a dust mass loss rate for each object by
modelling the spectral energy distribution and the gas mass loss rate by
solving the equation of motion for the dust drag wind. The derived mass loss
rates show a strong correlation with the silicate optical depth as well as that
of the water-ice. The stars have a high mass loss rate (> 1.0E-4 Msun/yr) with
an average gas-to-dust mass ratio of 110. In objects which show the 3.1um
water-ice absorption, the near-IR slope is much steeper than those with no
water-ice. Comparison between our calculated mass loss rates and those derived
from OH and CO observations indicates that these stars have recently increased
their mass loss rates.


title: A KOSMA 7 deg^2 13CO 2--1 & 12CO 3--2 survey of the Perseus cloud

abstract:
  Characterizing the spatial and velocity structure of molecular clouds is a
first step towards a better understanding of interstellar turbulence and its
link to star formation. We present observations and structure analysis results
for a large-scale (~ 7.10 deg^2) 13CO J = 2--1 and 12 CO J = 3--2 survey
towards the nearby Perseus molecular cloud observed with the KOSMA 3m
telescope. We study the spatial structure of line-integrated and velocity
channel maps, measuring the $\Delta$-variance as a function of size scale. We
determine the spectral index $\beta$ of the corresponding power spectrum and
study its variation across the cloud and across the lines. We find that the
spectra of all CO line-integrated maps of the whole complex show the same
index, $\beta$ ~ 3.1, for scales between about 0.2 and 3pc, independent of
isotopomer and rotational transition. A complementary 2MASS map of optical
extinction shows a noticeably smaller index of 2.6. In contrast to the overall
region, the CO maps of individual subregions show a significant variation of
$\beta$. The 12CO 3--2 data provide e.g. a spread of indices between 2.9 in
L1455 and 3.5 in NGC1333. In general, active star forming regions show a larger
power-law exponent. We find that the $\Delta$-variance spectra of individual
velocity channel maps are very sensitive to optical depth effects clearly
indicating self-absorption in the densest regions. When studying the dependence
of the channel-map spectra as a function of the velocity channel width, the
expected systematic increase of the spectral index with channel width is only
detected in the blue line wings.This could be explained by a filamentary,
pillar-like structure which is left at low velocities while the overall
molecular gas is swept up by a supernova shock wave.


title: XMM-Newton observations of the brightest Ultraluminous X-ray sources

abstract:
  We present an analysis of 13 of the best quality EPIC ULX datasets. We
utilise the high signal-to-noise in these ULX spectra to investigate the best
descriptions of their spectral shape in the 0.3-10 keV range. Simple models of
an absorbed power-law or multicolour disc blackbody prove inadequate at
describing the spectra. Better fits are found using a combination of these two
components, with both variants of this model - a cool (0.2 keV) disc blackbody
plus hard power-law continuum, and a soft power-law continuum plus a warm (1.7
keV) disc blackbody - providing good fits to 8/13 ULX spectra. However, by
examining the data above 2 keV, we find evidence for curvature in the majority
of datasets, inconsistent with the dominance of a power-law in this regime. The
most successful empirical description of the spectra proved to be a combination
of a cool (0.2 keV) classic blackbody spectrum, plus a warm disc blackbody
(good fits to 10/13 ULX spectra). The best overall fits are provided by a
physically self-consistent accretion disc plus Comptonised corona model (diskpn
+ eqpair), which fits acceptably to 11/13 ULXs. This model provides a physical
explanation for the spectral curvature, namely that it originates in an
optically-thick corona, though the accretion disc photons seeding this corona
still originate in an apparently cool disc. We note similarities between this
fit and models of Galactic black hole binaries at high accretion rates. We
conclude that this analysis of the best spectral data for ULXs shows it to be
plausible that the majority of the population are high accretion rate
stellar-mass (perhaps up to 80-Msun) black holes, though we cannot
categorically rule out the presence of larger, 1000-Msun intermediate-mass
black holes (IMBHs) in individual sources with the current X-ray data.


title: MeV-GeV emission from neutron-loaded short gamma-ray burst jets

abstract:
  Recent discovery of the afterglow emission from short gamma-ray bursts
suggests that binary neutron star or black hole-neutron star binary mergers are
the likely progenitors of these short bursts. The accretion of neutron star
material and its subsequent ejection by the central engine implies a
neutron-rich outflow. We consider here a neutron-rich relativistic jet model of
short bursts, and investigate the high energy neutrino and photon emission as
neutrons and protons decouple from each other. We find that upcoming neutrino
telescopes are unlikley to detect the 50 GeV neutrinos expected in this model.
For bursts at z~0.1, we find that GLAST and ground-based Cherenkov telescopes
should be able to detect prompt 100 MeV and 100 GeV photon signatures,
respectively, which may help test the neutron star merger progenitor
identification.


title: The Warped HI Layer of the Outer Galaxy

abstract:
  Using the Leiden/Dwingeloo Survey (Hartmann & Burton 1997) of the Galactic
sky north of declination -30 degrees as the principal component of a composite
data cube, the structure of the warped HI layer of the outer Galaxy was
displayed by converting the data cube from heliocentric (l,b,v) coordinates to
galactocentric (R,theta,z) coordinates. We masked out known high-velocity-cloud
complexes that might otherwise have contaminated the resulting description of
the warped layer. We considered analogous displays under controlled
circumstances by using as input medium a simulation of the same complete
(l,b,v) data cube corresponding to a modeled HI Galaxy of known morphology and
kinematics. By varying this artificial input we were able to check our method
of converting the data cube and to put constraints on the global parameters
that have been used to explain different asymmetries in the heliocentric data.


title: A Brief History of Trans-Neptunian Space

abstract:
  The Edgeworth-Kuiper belt encodes the dynamical history of the outer solar
system. Kuiper belt objects (KBOs) bear witness to coagulation physics, the
evolution of planetary orbits, and external perturbations from the solar
neighborhood. We critically review the present-day belt's observed properties
and the theories designed to explain them. Theories are organized according to
a possible time-line of events. In chronological order, epochs described
include (1) coagulation of KBOs in a dynamically cold disk, (2) formation of
binary KBOs by fragmentary collisions and gravitational captures, (3) stirring
of KBOs by Neptune-mass planets (``oligarchs''), (4) eviction of excess
oligarchs, (5) continued stirring of KBOs by remaining planets whose orbits
circularize by dynamical friction, (6) planetary migration and capture of
Resonant KBOs, (7) creation of the inner Oort cloud by passing stars in an open
stellar cluster, and (8) collisional comminution of the smallest KBOs. Recent
work underscores how small, collisional, primordial planetesimals having low
velocity dispersion permit the rapid assembly of ~5 Neptune-mass oligarchs at
distances of 15-25 AU. We explore the consequences of such a picture. We
propose that Neptune-mass planets whose orbits cross into the Kuiper belt for
up to ~20 Myr help generate the high-perihelion members of the hot Classical
disk and Scattered belt. By contrast, raising perihelia by sweeping secular
resonances during Neptune's migration might fill these reservoirs too
inefficiently when account is made of how little primordial mass might reside
in bodies having sizes of order 100 km. These and other frontier issues in
trans-Neptunian space are discussed quantitatively.


title: Where is the Molecular Hydrogen in Damped Lyman-Alpha Absorbers?

abstract:
  We show in this paper why molecular millimeter absorption line searches in
DLAs have been unsuccessful. We use CO emission line maps of local galaxies to
derive the H2 column density distribution function f(N_H2) at z=0. We show that
it forms a natural extension to f(N_HI): the H2 distribution exceeds f(N_HI) at
N_H ~ 10^22 cm^-2 and exhibits a power law drop-off with slope ~ -2.5.
Approximately 97% of the H2 mass density rho_H2 is in systems above N_H2=10^21
cm^-2. We derive a value rho_H2 = 1.1 x 10^7 h_70 M_sun Mpc^-3, which is ~25%
the mass density of atomic hydrogen. Yet, the redshift number density of H2
above this N_H2 limit is only ~3 x 10^-4, a factor 150 lower than that for HI
in DLAs at z=0. Furthermore, we show that the median impact parameter between a
N_H2>10^21 cm^-2 absorber and the centre of the galaxy hosting the H2 gas is
only 2.5 kpc. Based on arguments related to the Schmidt law, we argue that H2
gas above this column density limit is associated with a large fraction of the
integral star formation rate density. Even allowing for an increased molecular
mass density at higher redshifts, the derived cross-sections indicate that it
is very unlikely to identify the bulk of the molecular gas in present quasar
absorption lines samples. We discuss the prospects for identifying this
molecular mass in future surveys.


title:
Silicon and Nickel Enrichment in Planet-Host Stars: Observations and
  Implications for the Core-Accretion Theory of Planet Formation

abstract:
  We present evidence that stars with planets exhibit statistically significant
silicon and nickel enrichment over the general metal-rich population. We also
present simulations which predict silicon enhancement of planet hosts within
the context of the core-accretion hypothesis for giant planet formation.
Because silicon and oxygen are both alpha elements, [Si/Fe] traces [O/Fe], so
the silicon enhancement in planet hosts predicts that these stars are
oxygen-rich as well. We present new numerical simulations of planet formation
by core accretion that establish the timescale on which a Jovian planet reaches
rapid gas accretion, t_rga, as a function of solid surface density sigma_solid:
(t_rga / 1 Myr) = (sigma_solid / 25.0 g cm^{-2})^{-1.44}. This relation enables
us to construct Monte Carlo simulations that predict the fraction of star-disk
systems that form planets as a function of [Fe/H], [Si/Fe], disk mass, outer
disk radius and disk lifetime. Our simulations reproduce both the known
planet-metallicity correlation and the planet-silicon correlation reported in
this paper. The simulations predict that 16% of Solar-type stars form
Jupiter-mass planets, in agreement with 12% predicted from extrapolation of the
observed planet frequency-semimajor axis distribution. Although a simple
interpretation of core accretion predicts that the planet-silicon correlation
should be much stronger than the planet-nickel correlation, we observe the same
degree of silicon and nickel enhancement in planet hosts. If this result
persists once more planets have been discovered, it might indicate a complexity
in the chemistry of planet formation beyond the simple accumulation of solids
in the core accretion theory.


title:
Propagation of very high energy gamma-rays inside massive binaries LS
  5039 and LSI +61 303

abstract:
  It is expected that high energy gamma-rays, if injected relatively close to
the massive stars in binary systems LS 5039 and LSI 61 3003, should be strongly
absorbed, initiating inverse Compton $e^\pm$ pair cascades in the anisotropic
radiation from stellar surfaces. We investigate influence of the propagation
effects on the spectral and angular features of the gamma-ray spectra emerging
from these two binary systems by applying the Monte Carlo method. Two different
hypothesis are considered: isotropic injection of primary gamma-rays with the
power law spectrum and electrons. It is concluded that propagation effects of
gamma-rays can be responsible for the spectral features observed from LS 5039.
The cascade processes occurring inside these binary systems significantly
reduce the gamma-ray opacity obtained in other works by simple calculations of
the escape of gamma-rays from the radiation fields of the massive stars. Both
systems provide very similar conditions for the TeV gamma-ray production at the
periastron passage. Any TeV gamma-ray flux at the apastron passage in LSI +61
303 will be relatively stronger with respect to its GeV flux than in LS 5039.
If gamma-rays are produced inside these binaries not far from the massive
stars, i.e. within a few stellar radii, then clear anticorrelation between the
GeV and TeV emission should be observed, provided that primary gamma-rays at
GeV and TeV energies are produced in the same process by the same population of
relativistic particles. These gamma-ray propagation features can be tested in
the near future by the multi-wavelength campaigns engaging the AGILE and GLAST
telescopes and the Cherenkov telescopes (e.g. MAGIC, HESS, VERITAS and
CANGAROO).


title: Newtonian mechanics of neutron superfluid in elastic star crust

abstract:
  To account for pulsar frequency glitches, it is necessary to use a neutron
star crust model allowing not only for neutron superfluidity but also for
elastic solidity. These features have been treated separarately in previous
treatments of crust matter, but are combined here in a unified treatment that
is based on the use of a Lagrangian master functon, so that the coherence the
system is ensured by the relevant Noether identities. As well as the model
obtained directly from the variation principle, the same master function can
provide other conservative alternatives, allowing in particular for the effect
of perfect vortex pinning. It is also shown how such models can be generalised
to allow for dissipative effects, including that of imperfect pinning, meaning
vortex drag or creep.


title: The rotating and accelerating Universe

abstract:
  An attempt is made to explain the spiral structure of spiral galaxies through
a possible rotation of the Universe. To this end, we write down a possible form
of the metric, and we calculate the necessary quantities (Rik, Tik, ...) in
order to form the Einstein equations. We find the two Einstein equations
pertaining to the Robertson-Walker metric and no rotation at all in this way,
if we assume p+e not= 0. There are introduced then two suitable rotational
motions in the universe, and we try to generalize again the Robertson-Walker
metric in this way. The result is again null, since it is found that the
corresponding angular velocities must vanish, for p+e not= 0. A third attempt
is finally done, without restricting ourselves to generalize any existing
cosmological model. We introduce again two suitable rotational motions, and we
form the appropriate Einstein equations. After solving them, we find that the
two rotations, corresponding to the usual rotations on a torus, dictate again
the equation of state p+e = 0. This solution is a steady state one, and it
describes naturally the observationally discovered acceleration of the Universe
(1998), without a cosmological constant and the ambiguous dark energy.


title: Multifrequency observations of the jets in the radio galaxy NGC 315

abstract:
  We present images of the jets in the nearby radio galaxy NGC 315 made with
the VLA at five frequencies between 1.365 and 5 GHz with resolutions between
1.5 and 45 arcsec FWHM. Within 15 arcsec of the nucleus, the spectral index of
the jets is 0.61. Further from the nucleus, the spectrum is flatter, with
significant transverse structure. Between 15 and 70 arcsec from the nucleus,
the spectral index varies from 0.55 on-axis to 0.44 at the edge. This spectral
structure suggests a change of dominant particle acceleration mechanism with
distance from the nucleus and the transverse gradient may be associated with
shear in the jet velocity field. Further from the nucleus, the spectral index
has a constant value of 0.47. We derive the distribution of Faraday rotation
over the inner +/-400 arcsec of the radio source and show that it has three
components: a constant term, a linear gradient (both probably due to our
Galaxy) and residual fluctuations at the level of 1 - 2 rad/m^2. These residual
fluctuations are smaller in the brighter (approaching) jet, consistent with the
idea that they are produced by magnetic fields in a halo of hot plasma that
surrounds the radio source. We model this halo, deriving a core radius of
approximately 225 arcsec and constraining its central density and
magnetic-field strength. We also image the apparent magnetic-field structure
over the first +/-200 arcsec from the nucleus.


title: Theories of GRB Early Afterglow

abstract:
  The rapid follow-up of gamma-ray burst (GRB) afterglows made possible by the
multi-wavelength satellite Swift, launched in November 2004, has put under a
microscope the GRB early post-burst behavior, This is leading to a significant
reappraisal and expansion of the standard view of the GRB early afterglow
behavior, and its connection to the prompt gamma-ray emission. In addition to
opening up the previously poorly known behavior on minutes to hours timescales,
two other new pieces in the GRB puzzle being filled in are the the discovery
and follow-up of short GRB afterglows, and the opening up of the $z\simg 6$
redshift range. We review some of the current theoretical interpretations of
these new phenomena.


title:
Sgr A* as probe of the theory of supermassive compact objects without
  event horizon

abstract:
  In the present paper some consequences of the hypothesis that the
supermassive compact object in the Galaxy centre relates to a class of objects
without event horizon are examined. The possibility of the existence of such
objects was substantiated by the author earlier. It is shown that accretion of
a surrounding gas can cause nuclear combustion in the surface layer which, as a
result of comptonization of the superincumbent hotter layer, may give a
contribution to the observed Sgr A* radiation in the range $10^{15} \div
10^{20} Hz$.
  It is found a contribution of the possible proper magnetic moment of the
object to the observed synchrotron radiation on the basis of Boltzmann's
equation for photons which takes into account the influence of gravity to their
motion and frequency. We arrive at the conclusion that the hypothesis of the
existence in the Galaxy centre of the object with such extraordinary
gravitational properties at least does not contradict observations.


title:
Variability of black hole accretion discs: The cool, thermal disc
  component

abstract:
  We extend the model of King et al. (2004) for variability in black hole
accretion discs, by taking proper account of the thermal properties of the
disc. Because the degree of variability in the King et al. (2004) model depends
sensitively on the ratio of disc thickness to radius, H/R, it is important to
follow the time-dependence of the local disc structure as the variability
proceeds. In common with previous authors, we develop a one-zone model for the
local disc structure. We agree that radial heat advection plays an important
role in determining the inner disc structure, and also find limit-cycle
behaviour. When the stochastic magnetic dynamo model of King et al. (2004) is
added to these models, we find similar variability behaviour to before.
  We are now better placed to put physical constraints on model parameters. In
particular, we find that in order to be consistent with the low degree of
variability seen in the thermal disc component of black hole binaries, we need
to limit the energy density of the poloidal field that can be produced by local
dynamo cells in the disc to less than a few percent of the energy density of
the dynamo field within the disc itself.


title:
Relative abundance pattern along the profile of high redshift Damped
  Lyman-alpha systems

abstract:
  We investigated abundance ratios along the profiles of six high-redshift
Damped Lyman-alpha systems, three of them associated with H2 absorption, and
derived optical depths in each velocity pixel. The variations of the pixel
abundance ratios were found to be remarkably small and usually smaller than a
factor of two within a profile. This result holds even when considering
independent sub-clumps in the same system. The depletion factor is
significantly enhanced only in those components where H2 is detected. There is
a strong correlation between [Fe/S] and [Si/S] abundances ratios, showing that
the abundance ratio patterns are definitely related to the presence of dust.
The depletion pattern is usually close to the one seen in the warm halo gas of
our Galaxy.


title: The Near-Infrared Surface Brightness Distribution of NGC4696

abstract:
  We present H-band observations of the elliptical galaxy NGC4696, the
brightest member of the Centaurus cluster of galaxies. We have measured its
light profile, using a two-dimensional fitting algorithm, out to a radius of
180 arcsec (37 h^{-1}_{70} kpc). The profile is well described by a de
Vaucouleurs law, with an effective radius of 35.3 +/- 1.0 h^{-1}_{70} kpc.
There is no need for the extra free parameter allowed by a Sersic law. Allowing
for a variation of 0.3% in the sky level, the profile obtained is compatible
with data from 2MASS. The profile shows no sign of either a truncation or an
extended halo.


title: QPOs: Einstein's gravity non-linear resonances

abstract:
  There is strong evidence that the observed kHz Quasi Periodic Oscillations
(QPOs) in the X-ray flux of neutron star and black hole sources in LMXRBs are
linked to Einstein's General Relativity. Abramowicz&Klu\'zniak (2001) suggested
a non-linear resonance model to explain the QPOs origin: here we summarize
their idea and the development of a mathematical toy-model which begins to
throw light on the nature of Einstein's gravity non-linear oscillations.


title: Seeing Star Formation Regions with Gravitational Microlensing

abstract:
  We qualitatively study the effects of gravitational microlensing on our view
of unresolved extragalactic star formation regions. Using a general
gravitational microlensing configuration, we perform a number of simulations
that reveal that specific imprints of the star forming region are imprinted,
both photometrically and spectroscopically, upon observations. Such
observations have the potential to reveal the nature and size of these star
forming regions, through the degree of variability observed in a monitoring
campaign, and hence resolve the star formation regions in distant galaxies
which are too small to be probed via more standard techniques.


title: Numerical Simulations of Penetration and Overshoot in the Sun

abstract:
  We present numerical simulations of convective overshoot in a two-dimensional
model of the solar equatorial plane. The simulated domain extends from 0.001
R_sun to 0.93 R_sun, spanning both convective and radiative regions. We show
that convective penetration leads to a slightly extended, mildly subadiabatic
temperature gradient beneath the convection zone below which there is a rapid
transition to a strongly subadiabatic region. A slightly higher temperature is
maintained in the overshoot region by adiabatic heating from overshooting
plumes. This enhanced temperature may partially account for the sound speed
discrepancy between the standard solar model and helioseismology. Simulations
conducted with tracer particles suggest that a fully mixed region exists down
to at least 0.687 R_sun.


title:
A simple analytical model for dark matter halo structure and adiabatic
  contraction

abstract:
  A simple analytical model for describing inner parts of dark matter halo is
considered. It is assumed that dark matter density is power-law. The model
deals with dark matter distribution function in phase space of adiabatic
invariants (radial action and angular momentum). Two variants are considered
for the angular part of the distribution function: narrow and broad
distribution. The model allows to describe explicitly the process of adiabatic
contraction of halo due to change of gravitational potential caused by
condensation of baryonic matter in the centre. The modification of dark matter
density in the centre is calculated, and is it shown that the standard
algorithm of adiabatic contraction calculation overestimates the compressed
halo density, especially in the case of strong radial anisotropy.


title:
Tail emission from a ring-like jet: its application to shallow decays of
  early afterglows and to GRB 050709

abstract:
  Similar to the pulsar, the magnetic axis and the spin axis of the gamma-ray
burst source may not lie on the same line. This may cause a ring-like jet due
to collimation of the precessing magnetic axis. We analyze the tail emission
from such a jet, and find that it has a shallow decay phase with temporal index
equal to -1/2 if the Lorentz factor of the ejecta is not very high. This phase
is consistent with the shallow decay phase of some early X-ray afterglow
detected by {\it{swift}}. The ring-like jet has a tail cusp with sharp rising
and very sharp decay. This effect can provide an explanation for the
re-brightening and sharp decay of the X-ray afterglow of GRB 050709.


title: The Tully-Fisher Relation in Cluster Cl0024+1654 at z=0.4

abstract:
  Using moderate-resolution Keck spectra, we have examined the velocity
profiles of 15 members of cluster Cl0024+1654 at z=0.4. WFPC2 images of the
cluster members have been used to determine structural parameters, including
disk sizes, orientations, and inclinations. We compare two methods of optical
rotation curve analysis for kinematic measurements. Both methods take seeing,
slit size and orientation, and instrumental effects into account and yield
similar rotation velocity measurements. Four of the galaxies in our sample
exhibit unusual kinematic signatures, such as non-circular motions. Our key
result is that the Cl0024 galaxies are marginally underluminous (0.50 +/- 0.23
mag), given their rotation velocities, as compared to the local Tully-Fisher
relation. In this analysis, we assume no slope evolution, and take into account
systematic differences between local and distant velocity and luminosity
measurements. Our result is particularly striking considering the Cl0024
members have very strong emission lines, and local galaxies with similar Halpha
equivalent widths tend to be overluminous on the Tully-Fisher relation. Cl0024
Tully-Fisher residuals appear to be correlated most strongly with galaxy
rotation velocities, indicating a possible change in the slope of the
Tully-Fisher relation. However, we caution that this result may be strongly
affected by magnitude selection and by the original slope assumed for the
analysis. Cl0024 residuals also depend weakly on color, emission line strength
and extent, and photometric asymmetry. In a comparison of stellar and gas
motions in two Cl0024 members, we find no evidence for counter-rotating stars
and gas, an expected signature of mergers.


title: Avoiding Dark Energy with 1/R Modifications of Gravity

abstract:
  Scalar quintessence seems epicyclic because one can choose the potential to
reproduce any cosmology (I review the construction) and because the properties
of this scalar seem to raise more questions than they answer. This is why there
has been so much recent interest in modified gravity. I review the powerful
theorem of Ostrogradski which demonstrates that the only potentially stable,
local modification of general relativity is to make the Lagrangian an arbitrary
function of the Ricci scalar. Such a theory can certainly reproduce the current
phase of cosmic acceleration without Dark Energy. However, this explanation
again seems epicyclic in that one can construct a function of the Ricci scalar
to support any cosmology (I give the technique). Models of this form are also
liable to problems in the way they couple to matter, both in terms of matter's
impact upon them and in terms of the long range gravitational force they
predict. Because of these problems my own preference for avoiding Dark Energy
is to bypass Ostrogradski's theorem by considering the fully nonlocal effective
action built up by quantum gravitational processes during the epoch of
primordial inflation.


title:
The sky distribution of positronium annihilation continuum emission
  measured with SPI/INTEGRAL

abstract:
  We present a measurement of the sky distribution of positronium (Ps)
annihilation continuum emission obtained with the SPI spectrometer on board
ESA's INTEGRAL observatory. The only sky region from which significant Ps
continuum emission is detected is the Galactic bulge. The Ps continuum emission
is circularly symmetric about the Galactic centre, with an extension of about 8
deg FWHM. Within measurement uncertainties, the sky distribution of the Ps
continuum emission is consistent with that found by us for the 511 keV
electron-positron annihilation line using SPI. Assuming that 511 keV line and
Ps continuum emission follow the same spatial distribution, we derive a Ps
fraction of 0.92 +/- 0.09. These results strengthen our conclusions regarding
the origin of positrons in our Galaxy based on observations of the 511 keV
line. In particular, they suggest that the main source of Galactic positrons is
associated with an old stellar population, such as Type Ia supernovae,
classical novae, or low-mass X-ray binaries. Light dark matter is a possible
alternative source of positrons.


title: Probing the Sagittarius stream with blue horizontal branch stars

abstract:
  We present 2-degree field spectroscopic observations of a sample of 96 A-type
stars selected from the Sloan Digital Sky Survey Data Release 3 (SDSS DR3). Our
aim is to identify blue horizontal branch (BHB) stars in order to measure the
kinematic properties of the tidal tails of the Sagittarius dwarf spheroidal
galaxy. We confine our attention to the 44 classifiable stars with spectra of
signal-to-noise ratio >15 per angstrom. Classification produces a sample of 29
BHB stars at distances 5-47 kpc from the Sun. We split our sample into three
bins based on their distance. We find 10 of the 12 stars at 14-25 kpc appear to
have coherent, smoothly varying radial velocities which are plausibly
associated with old debris in the Sagittarius tidal stream. Further
observations along the orbit and at greater distances are required to trace the
full extent of this structure on the sky. Three of our BHB stars in the
direction of the globular cluster Palomar (Pal) 5 appear to be in an
overdensity but are in the foreground of Pal 5. More observations are required
around this overdensity to establish any relation to Pal 5 and/or the Sgr
stream. We emphasize observations of BHB stars have unlimited potential for
providing accurate velocity and distance information in old distant halo
streams and globular clusters alike. The next generation multi-object
spectrographs provide an excellent opportunity to accurately trace the full
extent of such structures.


title: Evolution of the Black Hole - Bulge Relationship in QSOs

abstract:
  QSOs allow study of the evolution of the relationship between black holes in
galactic nuclei and their host galaxies. The black hole mass can be derived
from the widths of the broad emission lines, and the stellar velocity
dispersion (sigma_*) of the host galaxy can be inferred from the narrow
emission lines. Results based on [OIII] and [OII] line widths indicate that the
black hole mass - sigma_* relationship, at redshifts up to z ~ 2, is consistent
with no evolution or an increase of up to ~ 0.5 dex in black hole mass at fixed
sigma_*. CO line widths offer an estimate of sigma_* for luminous QSOs at high
redshifts. The available objects from z ~ 4 to 6 have very massive black holes,
\~ 10^9.5 M_sun, but their CO line widths suggest much smaller host galaxies
than would be expected by the local black hole mass - sigma_* relationship. The
most massive black holes must continue to reside in comparatively modest
galaxies today, because their number density inferred from QSO statistics
exceeds the present-day abundance of proportionally massive galaxies.


title: X-ray spectral transitions of black holes from RXTE All-Sky Monitor

abstract:
  We have analysed X-ray outbursts from several Galactic black hole (GBH)
transients, as seen by the ASM on board RXTE. We have used the best estimates
of distance and black hole mass to find their luminosity (scaled to the
Eddington limit), which allowed for direct comparison of many sources. We have
found two distinct hard-to-soft state transitions in the initial part of the
outburst. The distinction is made on the basis of the transition luminosity,
its duration, the shape of the track in the hardness-luminosity diagram, and
evolution of the hardness ratio. The bright/slow transition occurs at ~30 per
cent of Eddington (estimated bolometric) luminosity and takes >~30 days, during
which the source quickly reaches the intermediate/very high state and then
proceeds to the soft state at much slower pace. The dark/slow transition is
less luminous (<~10 per cent of Eddington), shorter (<~15 days) and the source
does not slow its transition rate before reaching the soft state. We speculate
that the distinction is due to irradiation and evaporation of the disc, which
sustains the Comptonizing corona in the bright intemediate/very high state.


title:
Recovery of the global magnetic field configuration of 78 Virginis from
  Stokes IQUV line profiles

abstract:
  The surface magnetic field configuration of the Ap star HD 118022 (78 Vir)
has been reconstructed in the framework of the magnetic charge distribution
(MCD) method from the analysis of Stokes $IQUV$ spectra obtained using the
MuSiCoS spectropolarimeter at Pic du Midi Observatory. Magnetically-sensitive
Fe~{\sc ii} lines were primarily employed in the analysis, supposing that iron
is evenly distributed over the stellar surface. We show that the Stokes $IQUV$
profile shapes and variations of 78 Vir can be approximately fit assuming a
global magnetic field configuration described by a slightly decentered,
inclined magnetic dipole of polar surface intensity approximately 3.3~kG. The
derived inclinations of the stellar rotational axis to the line of sight
$i=24\pm 5\degr$ as well as to the magnetic dipole axis $\beta=124\pm5\degr$
are in good agreement with previous estimations by other authors, whereas the
sky-projected position angle\thanks{$\Omega$ increases clockwise from the axis
to the North Celestial Pole and relates to the azimuth angle $\Theta$ specified
by Landolfi at al.~(\cite{Landolfi+93}) as $\Omega=360\degr-\Theta$.} of the
stellar rotation axis $\Omega\sim110\degr$ is reported here for the first time.
In addition, several lines of Cr~{\sc ii} and Ti~{\sc ii} were studied,
yielding evidence for non-uniform surface distributions of these elements, and
magnetic field results similar to those derived from Fe.


title:
Magnetized Tori around Kerr Black Holes: Analytic Solutions with a
  Toroidal Magnetic Field

abstract:
  The dynamics of accretion discs around galactic and extragalactic black holes
may be influenced by their magnetic field. In this paper we generalise the
fully relativistic theory of stationary axisymmetric tori in Kerr metric of
Abramowicz et al.(1978) by including strong toroidal magnetic field and
construct analytic solutions for barotropic tori with constant angular
momentum. This development is particularly important for the general
relativistic computational magnetohydrodynamics that suffers from the lack of
exact analytic solutions that are needed to test computer codes.


title: Milky Way Gas Dynamics

abstract:
  The Milky Way is made up of a central bar, a disk with embedded spiral arms,
and a dark matter halo. Observational and theoretical constraints for the
characteristic parameters of these components will be presented, with emphasis
on the constraints from the dynamics of the Milky Way gas. In particular, the
fraction of dark matter inside the solar radius, the location of the main
resonances, and the evidence for multiple pattern speeds will be discussed.


title: Hunt for cold H2 molecules

abstract:
  The bulk of the molecular component in galaxies is made of cold H2, which is
not observed directly, but which abundance is derived from indirect tracers
such as CO emission. The CO to H2 conversion ratio remains uncertain, and may
vary by large factors in special environments with different excitation or
metallicity. Recent cold gas discoveries (through gamma-rays or cold dust
emission) are reviewed and the most promising tracers in the future are
discussed, such as the primordial molecules HD and LiH, or the pure rotational
lines of excited H2*.


title: Separation of dwarf and giant stars with ROTSE-IIId

abstract:
  136 stars which were known to be the members of open cluster NGC 752 were
observed at R band with ROTSE-IIId telescope located at the Turkish National
Observatory (TUG) site. The data had been evaluated together with BV and 2MASS
photometric data. A new practical method for separating dwarf and giant was
described and applied. Evaluating the colour magnitude--diagrams with Padova
isochrones revealed metallicity similar to the Sun and an age of 1.41 Gyr for
the open cluster NGC 752.


title: [CII] 158$\mu$m Emission and Metallicity in PDRs

abstract:
  We study the effects of a metallicity variation on the thermal balance and
[CII] fine-structure line strengths in interstellar photon dominated regions
(PDRs). We find that a reduction in the dust-to-gas ratio and the abundance of
heavy elements in the gas phase changes the heat balance of the gas in PDRs.
The surface temperature of PDRs decreases as the metallicity decreases except
for high density ($n>10^6$ cm$^{-3}$) clouds exposed to weak ($\chi< 100$) FUV
fields where vibrational H$_2$-deexcitation heating dominates over
photoelectric heating of the gas. We incorporate the metallicity dependence in
our KOSMA-$\tau$ PDR model to study the metallicity dependence of [CII]/CO line
ratios in low metallicity galaxies. We find that the main trend in the
variation of the observed CII/CO ratio with metallicity is well reproduced by a
single spherical clump, and does not necessarily require an ensemble of clumps
as in the semi-analytical model presented by Bolatto et al. (1999).


title: How many SNeIa do we need to detect the effect of weak lensing ?

abstract:
  We show that as many as 4000 SNeIa may be required to detect the effect of
weak lensing on their flux distribution with a high level of significance.
However, if the intrinsic SNeIa magnitude dispersion is unknown one needs an
even higher number of SNeIa (an order of magnitude more) to reach a similar
level of statistical significance. Moreover, the ability to separate the
lensing contribution from the intrinsic scatter depends sensitively on the
amplitude of the latter. Using a Kolmogorov - Smirnov (K-S) test we check how
the required number of SNeIa changes with level of significance. Our model
incorporates a completely analytical description of weak lensing which has been
tested extensively against numerical simulations. Thus, future missions such as
SNAP may be able to detect non-Gaussianity at a lower significance level of 10%
(through the K-S test) only if the intrinsic scatter is known from external
data (e.g. from low redshift observations) whereas ALPACA with 100,000 SNe will
definitely detect non-Gaussianity with a very high confidence even if the
intrinsic magnitude dispersion is not known a priori.


title:
Optical and Near-Infrared Observations of the Peculiar Type Ia Supernova
  1999ac

abstract:
  We present 39 nights of optical photometry, 34 nights of infrared photometry,
and 4 nights of optical spectroscopy of the Type Ia SN 1999ac. This supernova
was discovered two weeks before maximum light, and observations were begun
shortly thereafter. At early times its spectra resembled the unusual SN 1999aa
and were characterized by very high velocities in the Ca II H and K lines, but
very low velocities in the Si II 6355 A line. The optical photometry showed a
slow rise to peak brightness but, quite peculiarly, was followed by a more
rapid decline from maximum. Thus, the B- and V-band light curves cannot be
characterized by a single stretch factor. We argue that the best measure of the
nature of this object is not the decline rate parameter Delta m_15 (B). The B-V
colors were unusual from 30 to 90 days after maximum light in that they evolved
to bluer values at a much slower rate than normal Type Ia supernovae. The
spectra and bolometric light curve indicate that this event was similar to the
spectroscopically peculiar slow decliner SN 1999aa.


title:
Massive and Red Objects predicted by a semianalytical model of galaxy
  formation

abstract:
  We study whether hierarchical galaxy formation in a concordance $\Lambda$CDM
universe can produce enough massive and red galaxies compared to the
observations. We implement a semi-analytical model in which the central black
holes gain their mass during major mergers of galaxies and the energy feedback
from active galaxy nuclei (AGN) suppresses the gas cooling in their host halos.
The energy feedback from AGN acts effectively only in massive galaxies when
supermassive black holes have been formed in the central bulges. Compared with
previous models without black hole formation, our model predicts more massive
and luminous galaxies at high redshift, agreeing with the observations of K20
up to $z\sim 3$. Also the predicted stellar mass density from massive galaxies
agrees with the observations of GDDS. Because of the energy feedback from AGN,
the formation of new stars is stopped in massive galaxies with the termination
of gas cooling and these galaxies soon become red with color $R-K>$5 (Vega
magnitude), comparable to the Extremely Red Objects (EROs) observed at redshift
$z\sim$1-2. Still the predicted number density of very EROs is lower than
observed at $z\sim 2$, and it may be related to inadequate descriptions of dust
extinction, star formation history and AGN feedback in those luminous galaxies.


title: The UV Scattering Halo of the Central Source Associated with Eta Carinae

abstract:
  We have made an extensive study of the UV spectrum of Eta Carinae, and find
that we do not directly observe the star and its wind in the UV. Because of
dust along our line of sight, the UV light that we observe arises from
bound-bound scattering at large impact parameters. We obtain a reasonable fit
to the UV spectrum by using only the flux that originates outside 0.033". This
explains why we can still observe the primary star in the UV despite the large
optical extinction -- it is due to the presence of an intrinsic coronagraph in
the Eta Carinae system, and to the extension of the UV emitting region. It is
not due to peculiar dust properties alone. We have computed the spectrum of the
purported companion star, and show that it could only be directly detected in
the UV spectrum preferentially in the Far Ultraviolet Spectroscopic Explorer
(FUSE) spectral region (912-1175 Ang.). However, we find no direct evidence for
a companion star, with the properties indicated by X-ray studies and studies of
the Weigelt blobs, in UV spectra. This might be due to reprocessing of the
companion's light by the dense stellar wind of the primary. Broad FeII and
[FeII] emission lines, which form in the stellar wind, are detected in spectra
taken in the SE lobe, 0.2" from the central star. The wind spectrum shows some
similarities to the spectra of the B & D Weigelt blobs, but also shows some
marked differences in that high excitation lines, and lines pumped by Ly-alpha,
are not seen. The detection of the broad lines lends support to our
interpretation of the UV spectrum, and to our model for Eta Carinae.


title: Rate of Period Change as a Diagnostic of Cepheid Properties

abstract:
  Rate of period change $\dot{P}$ for a Cepheid is shown to be a parameter that
is capable of indicating the instability strip crossing mode for individual
objects, and, in conjunction with light amplitude, likely location within the
instability strip. Observed rates of period change in over 200 Milky Way
Cepheids are demonstrated to be in general agreement with predictions from
stellar evolutionary models, although the sample also displays features that
are inconsistent with some published models and indicative of the importance of
additional factors not fully incorporated in models to date.


title:
Evidence for Line Broadening by Electron Scattering in the Broad Line
  Region of NGC 4395

abstract:
  A high quality Keck spectrum of the Halpha line in NGC 4395 reveals symmetric
exponential wings, fv\propto e^{-v/sigma}, with sigma~500km/s. The wings extend
out to >2500km/s from the line core, and down to a flux density of <10^-3 of
the peak flux density. Numerical and analytic calculations indicate that
exponential wings are expected for optically thin, isotropic, thermal electron
scattering. Such scattering produces exponential wings with sigma=1.1sigma_e(ln
tau_e^-1)^0.45, where sigma_e is the electron velocity dispersion, and tau_e is
the electron scattering optical depth. The Halpha wings in NGC 4395 are well
fit by an electron scattering model with tau_e=0.34, and an electron
temperature T_e=1.1x10^4K. Such conditions are produced in photoionized gas
with an ionization parameter U=0.3, as expected in the broad line region (BLR).
Similar analysis of the [O III] 5007 line yields tau_e<0.01, consistent with
the lower ionization in the narrow line region. If the electron scattering
interpretation is correct, there should be a tight correlation between tau_e
and the ionizing flux on time scales shorter than the BLR dynamical time, or ~1
week for NGC 4395. In contrast, the value of sigma should remain nearly
constant on these time scales. Such wings may be discernible in other objects
with unusually narrow Balmer lines, and they can provide a useful direct probe
of T_e and tau_e in the BLR.


title:
Spectra of the spreading layers on the neutron star surface and
  constraints on the neutron star equation of state

abstract:
  Spectra of the spreading layers on the neutron star surface are calculated on
the basis of the Inogamov-Sunyaev model taking into account general relativity
correction to the surface gravity and considering various chemical composition
of the accreting matter. Local (at a given latitude) spectra are similar to the
X-ray burst spectra and are described by a diluted black body. Total spreading
layer spectra are integrated accounting for the light bending, gravitational
redshift, and the relativistic Doppler effect and aberration. They depend
slightly on the inclination angle and on the luminosity. These spectra also can
be fitted by a diluted black body with the color temperature depending mainly
on a neutron star compactness. Owing to the fact that the flux from the
spreading layer is close to the critical Eddington, we can put constraints on a
neutron star radius without the need to know precisely the emitting region area
or the distance to the source. The boundary layer spectra observed in the
luminous low-mass X-ray binaries, and described by a black body of color
temperature Tc=2.4+-0.1 keV, restrict the neutron star radii to R=14.8+- 1.5 km
(for a 1.4-Msun star and solar composition of the accreting matter), which
corresponds to the hard equation of state.


title: A radio and infrared exploration of the Cygnus X-3 environments

abstract:
  To confirm, or rule out, the possible hot spot nature of two previously
detected radio sources in the vicinity of the Cygnus X-3 microquasar.
  We present the results of a radio and near infrared exploration of the
several arc-minute field around the well known galactic relativistic jet source
Cygnus X-3 using the Very Large Array and the Calar Alto 3.5~m telescope.
  The data this paper is based on do not presently support the hot spot
hypothesis. Instead, our new observations suggest that these sources are most
likely background or foreground objects. Actually, none of them appears to be
even barely extended as would be expected if they were part of a bow shock
structure. Our near infrared observations also include a search for extended
emission in the Bracket $\gamma$ (2.166 $\mu$m) and $H_{2}$ (2.122 $\mu$m)
lines as possible tracers of shocked gas in the Cygnus X-3 surroundings. The
results were similarly negative and the corresponding upper limits are
reported.


title: Search for New Open Clusters in Huge Catalogues

abstract:
  Current catalogues of open clusters are rather heterogeneous and incomplete
lists of clusters than true catalogues. Before there has been no attempts of
automatic search for open clusters in huge photometric catalogues using
homogeneous all-sky approach.
  We have developed such a method based on extraction from catalogue and
successive analysis of stellar densities using the colour-magnitude diagrams.
Our algorithm finds density peaks and then verifies the significance of these
peaks exploiting the fact that in real clusters only stars lying on the
isochrone must show density peaks, in contrast with stars lying far from the
isochrone on the CMD. In addition such procedure allows to determine the
physical parameters: age, distance and color excess of open clusters.
  Preliminary study of 150 sq. degrees in Galaxy anticenter region yielded
several dozens of new clusters. The software developed will allow to build
first homogeneous all-sky open cluster catalogue (it will include essentially
refined data for known clusters as well) based on 2MASS data.


title: The COMPLETE Nature of the Warm Dust Ring in Perseus

abstract:
  The Perseus molecular cloud complex is a ~30pc long chain of molecular clouds
most well-known for the two star-forming clusters NGC1333 and IC348 and the
well-studied outflow source in B5. However, when studied at mid- to
far-infrared wavelengths the region is dominated by a ~10pc diameter shell of
warm dust, likely generated by an HII region caused by the early B-star
HD278942. Using a revised calibration technique the COMPLETE team has produced
high-sensitivity temperature and column-density maps of the Perseus region from
IRAS Sky Survey Atlas (ISSA) 60 and 100um data. In this paper, we combine the
ISSA based dust-emission maps with other observations collected as part of the
COMPLETE Survey, along with archival H-alpha and MSX observations. Molecular
line observations from FCRAO and extinction maps constructed by applying the
NICER method to the 2MASS catalog provide independent estimates of the ``true''
column-density of the shell. H-alpha emission in the region of the shell
confirms that it is most likely an HII region located behind the cloud complex,
and 8um data from MSX indicates that the shell may be interacting with the
cloud. Finally, the two polarisation components previously seen towards
background stars in the region can be explained by the association of the
stronger component with the shell. If confirmed, this would be the first
observation of a parsec-scale swept-up magnetic field.


title: A Broader Perspective on the GRB-SN Connection

abstract:
  Over the last few years our understanding of local Type Ibc supernovae and
their connection to long-duration gamma-ray bursts has been revolutionized.
Recent discoveries have shown that the emerging picture for core-collapse
explosions is one of diversity. Compiling data from our dedicated radio survey
of SNe Ibc and our comprehensive HST survey of GRB-SNe together with
ground-based follow-up campaigns, I review our current understanding of the
GRB-SN connection. In particular, I compare local SNe Ibc with GRB-SNe based on
the following criteria: (1) the distribution of optical peak magnitudes which
serve as a proxy for the mass of Nickel-56 produced in the explosion, (2) radio
luminosity at early time (few days to weeks) which provides a measure of the
energy coupled to on-axis relativistic ejecta, and (3) radio luminosity at late
time (several years) which constrains the emission from GRB jets initially
directed away from our line-of-sight. By focusing on these three points, I will
describe the complex picture of stellar death that is emerging.


title: A Magellanic Origin for the Warp of the Galaxy

abstract:
  We show that a Magellanic Cloud origin for the warp of the Milky Way can
explain most quantitative features of the outer HI layer recently identified by
Levine, Blitz & Heiles (2005). We construct a model similar to that of Weinberg
(1998) that produces distortions in the dark matter halo, and we calculate the
combined effect of these dark-halo distortions and the direct tidal forcing by
the Magellanic Clouds on the disk warp in the linear regime. The interaction of
the dark matter halo with the disk and resonances between the orbit of the
Clouds and the disk account for the large amplitudes observed for the vertical
m=0,1,2 harmonics. The observations lead to six constraints on warp forcing
mechanisms and our model reasonably approximates all six. The disk is shown to
be very dynamic, constantly changing its shape as the Clouds proceed along
their orbit. We discuss the challenges to MOND placed by the observations.


title:
The Cumulative Bakground of High-Energy Neutrinos from Starburst
  Galaxies

abstract:
  We show that starburst galaxies convert efficiently cosmic-rays into pions,
which in turn decay into high-energy neutrinos and photons. The cumulative
background of GeV neutrinos is 10^{-7}GeV/cm^2/s/sr. Its extrapolation to
higher neutrino energies depends on the energy spectrum of the injected
cosmic-rays and is proportional to E^{-0.15+-0.1} up to E~0.3PeV and possibly
higher neutrino energies. This flux, which constitutes a lower limit to the
high energy extra-Galactic neutrino flux, is likely to be detectable by
forthcoming km-scale neutrino telescopes.


title:
Structure of Passive Circumstellar Disks: Beyond the Two-Temperature
  Approximation

abstract:
  Structure and spectral energy distributions (SEDs) of externally irradiated
circumstellar disks are often computed on the basis of the two-temperature
model of Chiang & Goldreich. We refine these calculations by using a more
realistic temperature profile which is continuous at all optical depths and
thus goes beyond the two-temperature model. It is based on the approximate
solution of the radiation transfer in the disk obtained from the
frequency-integrated moment equations in the Eddington approximation. We come
up with a simple procedure (``constant g_z approximation'') for treating the
vertical structure of the disk in regions where its optical depth to stellar
radiation is high. This allows us to obtain expressions for the vertical
profiles of density and pressure at every point in the disk and to determine
the shape of its surface. Armed with these analytical results we calculate the
full radial structure of the disk and demonstrate that it favorably agrees with
the results of direct numerical calculations. We also describe a simple and
efficient way of the SED calculation based on our adopted temperature profile.
Resulting spectra provide very good match (especially at short wavelengths) to
the results of more detailed (but also more time-consuming) SED calculations
solving the full frequency- and angle-dependent radiation transfer within the
disk.


title: The Vertical Structure of the Outer Milky Way HI Disk

abstract:
  We examine the outer Galactic HI disk for deviations from the b=0 plane by
constructing maps of disk surface density, mean height, and thickness. We find
that the Galactic warp is well described by a vertical offset plus two Fourier
modes of frequency 1 and 2, all of which grow with Galactocentric radius.
Adding the m=2 mode accounts for the large asymmetry between the northern and
southern warps. We use a Morlet wavelet transform to investigate the spatial
and frequency localization of higher frequency modes; these modes are often
referred to as "scalloping." We find that the m=10 and 15 scalloping modes are
well above the noise, but localized; this suggests that the scalloping does not
pervade the whole disk, but only local regions.


title:
Efficient Merger of Binary Supermassive Black Holes in Non-Axisymmetric
  Galaxies

abstract:
  Binary supermassive black holes form naturally in galaxy mergers, but their
long-term evolution is uncertain. In spherical galaxies, N-body simulations
show that binary evolution stalls at separations much too large for significant
emission of gravitational waves (the "final parsec problem"). Here, we follow
the long-term evolution of a massive binary in more realistic, triaxial and
rotating galaxy models. We find that the binary does not stall. The binary
hardening rates that we observe are sufficient to allow complete coalescence of
binary SBHs in 10 Gyr or less, even in the absence of collisional loss-cone
refilling or gas-dynamical torques, thus providing a potential solution to the
final parsec problem.


title:
Illuminating the dark ages of the universe: the exact backreaction in
  the SFRW model and the acceleration of the universe

abstract:
  Within the recently proposed structured FRW model universe the averaged
Einstein equations are derived. The backreaction turns out to have an
interesting behavior. Its equivalent density and pressure, being proportional,
are negative at early times of the dark ages of the universe, and change sign
near our present time in our local patch. In addition to explaining the
observed dimming of the SNIa it leads to new effects for small cosmic redshifts
and also to the difference between the local and global Hubble parameter.
Interpreting the backreaction in the FRW-{\it picture}, it is equivalent to a
time dependent dark energy with $w = -1$.


title:
Chandra Observations of SDSS J1004+4112: Constraints on the Lensing
  Cluster and Anomalous X-Ray Flux Ratios of the Quadruply Imaged Quasar

abstract:
  We present results from Chandra observations of SDSS J1004+4112, a strongly
lensed quasar system with a maximum image separation of 15". All four bright
images of the quasar, as well as resolved X-ray emission originating from the
lensing cluster, are clearly detected. The emission from the lensing cluster
extends out to approximately 1.5 arcmin. We measure the bolometric X-ray
luminosity and temperature of the lensing cluster to be 4.7e44 erg s^-1 and 6.4
keV, consistent with the luminosity-temperature relation for distant clusters.
The mass estimated from the X-ray observation shows excellent agreement with
the mass derived from gravitational lensing. The X-ray flux ratios of the
quasar images differ markedly from the optical flux ratios, and the combined
X-ray spectrum of the images possesses an unusually strong Fe Kalpha emission
line, both of which are indicative of microlensing.


title:
The finite source size effect and the wave optics in gravitational
  lensing

abstract:
  We investigate the finite source size effect in the context of the wave
optics in the gravitational lensing. The magnification of an extended source is
presented in an analytic manner for the singular isothermal sphere lens model
as well as the point mass lens model with the use of the thin lens
approximation. The condition that the finite source size effect becomes
substantial is demonstrated. As an application, we discuss possible
observational consequences of the finite source size effect on astrophysical
systems.


title: Constraining B in galaxy clusters from statistics of giant radio halos

abstract:
  There are several possibilities to constrain the value of the magnetic field
in the ICM, the most direct ones being the combination of inverse Compton and
synchrotron observations, and the Faraday rotation measures. Here we discuss on
the possibility to provide constraints on the magnetic field in the ICM from
the analysis of the statistical properties of the giant radio halos, Mpc--scale
diffuse radio emission in galaxy clusters. Present observations of a few well
studied radio halos can be interpreted under the hypothesis that the emitting
relativistic electrons are re-accelerated on their way out. By using
statistical calculations carried out in the framework of the re-acceleration
model we show that the observed radio--power vs cluster mass correlation in
radio halos can be reproduced only by assuming $\mu$G fields in the ICM and a
scaling of the magnetic field with cluster mass $B \propto M_v^b$, with $b \geq
0.6$. We also show that the expected occurrence of radio halos with mass and
redshift, and their number counts are sensitive to the magnetic field intensity
in massive galaxy clusters and to the scaling of B with cluster mass. Thus
future deep surveys of radio halos would provide constraints on B in galaxy
clusters.


title: Interacting galaxies and cosmological parameters

abstract:
  We propose a (physical)-geometrical method to measure the present rates of
the density cosmological parameters for a Friedmann-Lemaitre universe. The
distribution of linear separations between two interacting galaxies,when both
of them undergo a first massive starburst, is used as a standard of length.
Statistical properties of the linear separations of such pairs of
``interactivated'' galaxies are estimated from the data in the Two Degree Field
Galaxy Redshift Survey. Synthetic samples of interactivated pairs are generated
with random orientations and a likely distribution of redshifts. The resolution
of the inverse problem provides the probability densities of the retrieved
cosmological parameters. The accuracies that can be achieved by that method on
matter and cosmological constant densities parameters are computed depending on
the size of ongoing real samples. Observational prospects are investigated as
the foreseeable surface densities on the sky and magnitudes of those objects.


title: TeV Gamma-Rays from Old Supernova Remnants

abstract:
  We study the emission from an old supernova remnant (SNR) with an age of
around 10^5 yrs and that from a giant molecular cloud (GMC) encountered by the
SNR. When the SNR age is around 10^5 yrs, proton acceleration is efficient
enough to emit TeV gamma-rays both at the shock of the SNR and that in the GMC.
The maximum energy of primarily accelerated electrons is so small that TeV
gamma-rays and X-rays are dominated by hadronic processes, pi^0-decay and
synchrotron radiation from secondary electrons, respectively. However, if the
SNR is older than several 10^5 yrs, there are few high-energy particles
emitting TeV gamma-rays because of the energy loss effect and/or the wave
damping effect occurring at low-velocity isothermal shocks. For old SNRs or
SNR-GMC interacting systems capable of generating TeV gamma-ray emitting
particles, we calculated the ratio of TeV gamma-ray (1-10 TeV) to X-ray (2-10
keV) energy flux and found that it can be more than ~10^2. Such a source
showing large flux ratio may be a possible origin of recently discovered
unidentified TeV sources.


title:
Hardening in a Time--Evolving Stellar Background: Hyper--Velocity Stars,
  Orbital Decay and Prediction for Lisa

abstract:
  We study the long-term evolution of massive black hole binaries (MBHBs) at
the centers of galaxies using detailed full three-body scattering experiments.
Stars, drawn from a distribution unbound to the binary, are ejected by the
gravitational slingshot. We quantify the effect of secondary slingshots --
stars returning on small impact parameter orbits to have a second super-elastic
scattering with the MBHB -- on binary separation. Even in the absence of
two-body relaxation or gas dynamical processes, very unequal mass binaries of
mass M=10^7 solar masses can shrink to the gravitational wave emission regime
in less than a Hubble time, and are therefore a target for the planned Laser
Interferometer Space Antenna (LISA). Three-body interactions create a
subpopulation of hypervelocity stars on nearly radial, corotating orbits, with
a spatial distribution that is initially highly flattened in the inspiral plane
of the MBHB, but becomes more isotropic with decreasing binary separation. The
mass ejected is ~0.7 times the binary reduced mass, and most of the stars are
ejected in an initial burst lasting much less than a bulge crossing time.


title: Bias-free Measurement of Giant Molecular Cloud Properties

abstract:
  (abridged) We review methods for measuring the sizes, line widths, and
luminosities of giant molecular clouds (GMCs) in molecular-line data cubes with
low resolution and sensitivity. We find that moment methods are robust and
sensitive -- making full use of both position and intensity information -- and
we recommend a standard method to measure the position angle, major and minor
axis sizes, line width, and luminosity using moment methods. Without
corrections for the effects of beam convolution and sensitivity to GMC
properties, the resulting properties may be severely biased. This is
particularly true for extragalactic observations, where resolution and
sensitivity effects often bias measured values by 40% or more. We correct for
finite spatial and spectral resolutions with a simple deconvolution and we
correct for sensitivity biases by extrapolating properties of a GMC to those we
would expect to measure with perfect sensitivity. The resulting method recovers
the properties of a GMC to within 10% over a large range of resolutions and
sensitivities, provided the clouds are marginally resolved with a peak
signal-to-noise ratio greater than 10. We note that interferometers
systematically underestimate cloud properties, particularly the flux from a
cloud. The degree of bias depends on the sensitivity of the observations and
the (u,v) coverage of the observations. In the Appendix to the paper we present
a conservative, new decomposition algorithm for identifying GMCs in
molecular-line observations. This algorithm treats the data in physical rather
than observational units, does not produce spurious clouds in the presence of
noise, and is sensitive to a range of morphologies. As a result, the output of
this decomposition should be directly comparable among disparate data sets.


title:
Screw Instability of Magnetic Field and Gamma-Ray Bursts in Type Ib/C
  Supernovae

abstract:
  A toy model for gamma-ray burst supernovae (GRB-SNe) is discussed by
considering the effects of screw instability of magnetic field in black hole
(BH) magnetosphere. The screw instability in the Blandford-Znajek (BZ) process
(henceforth SIBZ) can coexist with the screw instability in the magnetic
coupling (MC) process (henceforth SIMC). It turns out that both SIBZ and SIMC
occur inevitably, provided that the following parameters are greater than some
critical values, i.e., (i) the BH spin, (ii) the power-law index describing the
magnetic field at the disk, and (iii) the vertical height of the astrophysical
load above the equatorial plane of the rotating BH. The features of several
GRBs are well fitted. In our model the durations of the long GRBs depend on the
evolve time of the half-opening angle. A small fraction of energy is extracted
from the BH via the BZ process to power a GRB, while a large fraction of energy
is extracted from the BH via the MC process to power an associated supernova.
In addition, the variability time scales of tens of msec in the light curves of
the GRBs are fitted by two successive flares due to SIBZ.


title:
GRB 050315: A step in the proof of the uniqueness of the overall GRB
  structure

abstract:
  Using the Swift data of GRB 050315, we progress in proving the uniqueness of
our theoretically predicted Gamma-Ray Burst (GRB) structure as composed by a
proper-GRB, emitted at the transparency of an electron-positron plasma with
suitable baryon loading, and an afterglow comprising the "prompt radiation" as
due to external shocks. Detailed light curves for selected energy bands are
theoretically fitted in the entire temporal region of the Swift observations
ranging over 10^6 seconds.


title:
A Bima Array Survey of Molecules in Comets Linear (C/2002 T7) and Neat
  (C/2001 Q4)

abstract:
  We present an interferometric search for large molecules, including methanol,
methyl cyanide, ethyl cyanide, ethanol, and methyl formate in comets LINEAR
(C/2002 T7) and NEAT (C/2001 Q4) with the Berkeley-Illinois-Maryland
Association (BIMA) array. In addition, we also searched for transitions of the
simpler molecules CS, SiO, HNC, HN13C and 13CO . We detected transitions of
methanol and CS around Comet LINEAR and one transition of methanol around Comet
NEAT within a synthesized beam of ~20''. We calculated the total column density
and production rate of each molecular species using the variable temperature
and outflow velocity (VTOV) model described by Friedel et al.(2005).Considering
the molecular production rate ratios with respect to water, Comet T7 LINEAR is
more similar to Comet Hale-Bopp while Comet Q4 NEAT is more similar to Comet
Hyakutake. It is unclear, however, due to such a small sample size, whether
there is a clear distinction between a Hale-Bopp and Hyakutake class of comet
or whether comets have a continuous range of molecular production rate ratios.


title: Theoretical Interpretation of GRB 031203 and URCA-3

abstract:
  We present an analysis of the late time X-ray emission (URCA-3) connected
with GRB 031203 and SN 2003lw.