title: Diagnostics of SS433 with the RXTE

abstract:
  We present analysis of extensive monitoring of SS433 by the RXTE observatory
collected over the period 1996-2005. The difference between energy spectra
taken at different precessional and orbital phases shows the presence of a
strong photoabsorption near the optical star, probably due to its powerful
dense wind. Assuming that a precessing accretion disk is thick, we recover the
temperature profile in the X-ray emitting jet that best fits the observed
precessional variations of the X-ray emission temperature. The hottest visible
part of the X-ray jet is located at a distance of $l_0/a\sim0.06-0.09$, or
$\sim2-3\times10^{11}$cm from the central compact object and has a temperature
of about $T_{\rm max}\sim30$ keV. We discovered appreciable orbital X-ray
eclipses at the ``crossover'' precessional phases (jets are in the plane of the
sky, disk is edge-on) which put a lower limit on the size of the optical
component $R/a\ga0.5$ and an upper limit on a mass ratio of binary companions
$q=M_{\rm x}/M_{\rm opt}\la0.3-0.35$. The size of the eclipsing region can be
larger than secondary's Roche lobe because of substantial photoabsorption by
dense stellar wind. This must be taken into account when evaluating the mass
ratio from analysis of X-ray eclipses.


title: Accretion to a Magnetized Neutron Star in the "Propeller" Regime

abstract:
  We investigate spherical accretion to a rotating magnetized star in the
"propeller" regime using axisymmetric resistive magnetohydrodynamic
simulations. The regime is predicted to occur if the magnetospheric radius is
larger than the corotation radius and smaller than the light cylinder radius.
The simulations show that accreting matter is expelled from the equatorial
region of the magnetosphere and that it moves away from the star in a
supersonic, disk-shaped outflow. At larger radial distances the outflow slows
down and becomes subsonic. The equatorial matter outflow is initially driven by
the centrifugal force, but at larger distances the pressure gradient force
becomes significant. We find the fraction of the Bondi accretion rate which
accretes to the surface of the star.


title: Short timescale variability in the Faint Sky Variability Survey

abstract:
  We present the V band variability analysis of the point sources in the Faint
Sky Variability Survey on time scales from 24 minutes to tens of days. We find
that about one percent of the point sources down to V = 24 are variables. We
discuss the variability detection probabilities for each field depending on
field sampling, amplitude and timescale of the variability. The combination of
colour and variability information allows us to explore the fraction of
variable sources for different spectral types. We find that about 50 percent of
the variables show variability timescales shorter than 6 hours. The total
number of variables is dominated by main sequence sources. The distribution of
variables with spectral type is fairly constant along the main sequence, with 1
per cent of the sources being variable, except at the blue end of the main
sequence, between spectral types F0--F5, where the fraction of variable sources
increases to about 2 percent. For bluer sources, above the main sequence, this
percentage increases to about 3.5. We find that the combination of the sampling
and the number of observations allows us to determine the variability
timescales and amplitudes for a maximum of 40 percent of the variables found.
About a third of the total number of short timescale variables found in the
survey were not detected in either B or/and I. These show a similar variability
timescale distribution to that found for the variables detected in all three
bands.


title:
An Interactive Program for Correlative Studies of Solar Energetic
  Particle Events

abstract:
  We have developed an interactive program which shows the solar energetic
particle (SEP) intensity-time profile as observed by SOHO/ERNE, simultaneously
with the associated coronal mass ejection in optical imaging movies taken by
LASCO coronagraph, soft X-ray by YOHKOH, ultraviolet by EIT, DH radio emission
by WAVE/Wind, and the H$\alpha$ location for the solar flare and spectral radio
emission from the journal of geophysical data. The whole set of data will
provide increased scientific knowledge on the solar energetic particle events
and the solar phenomena associated with them, because in this program one can
see easily the temporal associations of each phenomenon during the evolution of
the particle intensity. The (SEP) intensity-time profile will give a clear view
to detect the velocity dispersion in the events, if it exists. The ERNE data
are commented in order to follow of phenomena associated with changes of the
intensity-time profiles. We introduce this set of data as an index for the
ERNE/SOHO solar energetic particle events. The interactive program is applied
for statistical, correlative study of SEP events observed on board SOHO.


title:
3.9 day orbital modulation in the TeV gamma-ray flux and spectrum from
  the X-ray binary LS 5039

abstract:
  New observations of LS 5039, a High Mass X-ray Binary comprising a massive
star and compact object, were carried out with the High Energy Stereoscopic
System of Cherenkov Telescopes (H.E.S.S.) in 2005 at very high energy (VHE)
gamma-ray energies. These observations reveal that its flux and energy spectrum
are modulated with the 3.9 day orbital period of the binary system. This is the
first time in gamma-ray astronomy that orbital modulation has been observed,
and periodicity clearly established using ground-based gamma-ray detectors. The
VHE gamma-ray emission is largely confined to half of the orbit, peaking around
the inferior conjunction epoch of the compact object. For this epoch, there is
also a hardening of the energy spectrum in the energy range between 0.2 TeV and
a few TeV. The flux vs. orbital phase profile provides the first clear
indication of gamma-ray absorption via pair production within an astrophysical
source, a process which is expected to occur if the gamma-ray production site
is situated within ~1 AU of the compact object. Moreover the production region
size must be not significantly greater than the binary separation (~0.15 AU).
Notably, these constraints are also considerably smaller than the collimated
outflows or jets (extending out to ~1000 AU) observed in LS 5039. The spectral
hardening could arise from variations with phase in the maximum electron
energies, and/or the dominant VHE gamma-ray production mechanism.


title:
Diffuse Interstellar Band at 5850 as a Member of 5797 Spectroscopic
  Family

abstract:
  The carriers of diffuse interstellar bands are still mysterious species.
There exist many arguments that diffuse bands at 5797 and 5850 angstroms have
the same carrier. Using high-resolution spectra of few dozens of reddened stars
we have searched mutual correlation between intensities of considered bands.
Results of our analysis indicate that 5797 and 5850 really tend to have the
same carrier.


title: Interstellar C2 Molecule as Seen in HST/STIS Data

abstract:
  Carbon chains are sometimes considered as possible carriers of some diffuse
interstellar bands. Spectroscopic observations in UV band carried by
spectrometer STIS fed with HST, give us the possibility to detect many
interstellar molecules. We focused our attention on C2 molecule and we detected
it in spectra of three reddened stars (HD27778, HD147933, HD207198).
Interstellar molecule C2 was detected as a set of absorption lines around 2313
angstroms.


title: Constraining the environment of GRB 990712 through emission line fluxes

abstract:
  The energy output in the gamma-ray burst (GRB) prompt emission and afterglow
phase is expected to photoionize the surrounding medium out to large radii.
Cooling of this gas produces line emission, particularly strong in the optical,
whose variability is a strong diagnostics of the gas density and geometry in
the close environment of the burst. We present the results of a spectral time
series analysis of the host galaxy of GRB 990712 observed up to ~6 years after
the burst. We analyze the emission line fluxes together with those of the
previous observations of the same GRB, in search for photoionization
signatures. We find that the emission line fluxes show no variation within the
uncertainities up to 6 years after the burst, and we use the measured line
intensities to set a limit on the density of the gas within a few parsecs of
the burst location. This is the first time that emission from cooling GRB
remnants is probed on years time scales.


title: Circumstellar Emission from Type Ib and Ic Supernovae

abstract:
  The presumed Wolf-Rayet star progenitors of Type Ib/c supernovae have fast,
low density winds and the shock waves generated by the supernova interaction
with the wind are not expected to be radiative at typical times of observation.
The injected energy spectrum of radio emitting electrons typically has an
observed index p=3, which is suggestive of acceleration in cosmic ray dominated
shocks. The early, absorbed part of the radio light curves can be attributed to
synchrotron self-absorption, which leads to constraints on the magnetic field
in the emitting region and on the circumstellar density. The range of
circumstellar densities inferred from the radio emission is somewhat broader
than that for Galactic Wolf-Rayet stars, if similar efficiencies of synchrotron
emission are assumed in the extragalactic supernovae. For the observed and
expected ranges of circumstellar densities to roughly overlap, a high
efficiency of magnetic field production in the shocked region is required
(epsilon_B ~ 0.1). For the expected densities around a Wolf-Rayet star, a
nonthermal mechanism is generally required to explain the observed X-ray
luminosities of Type Ib/c supernovae. Although the inverse Compton mechanism
can explain the observed X-ray emission from SN 2002ap if the wind parameters
are taken from the radio model, the mechanism is not promising for other
supernovae unless the postshock magnetic energy density is much smaller than
the electron energy density. In some cases another mechanism is definitely
needed and we suggest that it is X-ray synchrotron emission in a case where the
shock wave is cosmic ray dominated so that the electron energy spectrum
flattens at high energy. More comprehensive X-ray observations of a Type Ib/c
supernova are needed to determine whether this suggestion is correct.


title:
Are Diffuse High Energy Neutrinos and Gamma-Rays from Starburst Galaxies
  Observable?

abstract:
  Loeb and Waxman have argued that high energy neutrinos from the decay of
pions produced in interactions of cosmic rays with interstellar gas in
starburst galaxies would be produced with a large enough flux to be observable.
Their model is reexamined here and we obtain an upper limit to the diffuse
neutrino flux from starburst galaxies. The upper limit obtained here is a
factor of ~5 lower than the flux which they predict. Our predicted neutrino
flux would be below the atmospheric neutrino foreground flux at energies below
\~300 TeV and therefore would be unobservable. PeV neutrinos from starburst
galaxies are also unlikely to be detected. Compared with predicted fluxes from
other extragalactic high energy neutrino sources, starburst neutrinos with ~PeV
energies would have a flux considerably below that predicted for AGN models. We
also estimate an upper limit for the diffuse GeV gamma-ray flux from starburst
galaxies to be about two orders of magnitude below the observed gamma-ray
background, much less than the background from blazars and more than an order
of magnitude below that calculated by Thompson et al.


title: Predicted properties of RR Lyrae stars in the SDSS photometric system

abstract:
  The luminosities and effective temperatures, as well as the whole bolometric
lightcurves of nonlinear convective RR Lyrae models with 0.0001<Z<0.006 are
transformed into the SDSS photometric system. The obtained ugriz lightcurves,
mean magnitudes and colors, pulsation amplitudes and color-color loops are
shown and analytical relations connecting pulsational to intrinsic stellar
parameters, similarly to the ones currently used in the Johnson-Cousins
filters, are derived. Finally the behaviour in the color-color planes is
compared with available observations in the literature and possible systematic
uncertainties affecting this comparison are discussed.


title:
X-ray observations of the mass and entropy distributions in nearby
  galaxy clusters

abstract:
  I review some important aspects of the structural and statistical properties
of the nearby X-ray galaxy cluster population, discussing the new constraints
on mass profiles, the mass-temperature relation, and the entropy of the
intracluster medium which have become available from recent X-ray observations.


title:
New VLA observations of the SNR Puppis A: the radio properties and the
  correlatoin withe the X-ray emission

abstract:
  In this paper we report on a new study of the SNR Puppis A based on VLA
observations at 1425 MHz; the improvement represents a factor of two in angular
resolution and almost ten times in sensitivity compared to the best previous
image of Puppis A. This new image is used to compare with re-processed 327 MHz
data and ROSAT and Chandra images to investigate morphological and spectral
characteristics.


title:
The Serret-Andoyer Formalism in Rigid-Body Dynamics: I. Symmetries and
  Perturbations

abstract:
  This paper reviews the Serret-Andoyer (SA) canonical formalism in rigid-body
dynamics and presents some new results. As is well known, the problem of
unsupported and unperturbed rigid rotator can be reduced. The availability of
this reduction is offered by the underlying symmetry, which stems from
conservation of the angular momentum and rotational kinetic energy. When a
perturbation is turned on, these quantities are no longer preserved.
Nonetheless, the language of reduced description remains extremely instrumental
even in the perturbed case. We describe the canonical reduction performed by
the Serret-Andoyer (SA) method, and discuss its applications to attitude
dynamics and to the theory of planetary rotation. Specifically, we consider the
case of angular-velocity-dependent torques, and discuss the
variation-of-parameters-inherent antinomy between canonicity and osculation.
Finally, we address the transformation of the Andoyer variables into the
action-angle ones, using the method of Sadov.


title: Limits on CMBP B-Mode Measurements by Galactic Synchrotron Observations

abstract:
  The B-Mode of the Cosmic Microwave Background Polarization (CMBP) promises to
detect the gravitational wave background left by Inflation and explore this
very early period of the Universe. In spite of its importance, however, the
cosmic signal is tiny and can be severely limited by astrophysical foregrounds.
In this contribution we discuss about one of the main contaminant, the diffuse
synchrotron emission of the Galaxy. We briefly report about recent deep
observations at high Galactic latitudes, the most interesting for CMB purposes
because of the low emission, and discuss the contraints in CMBP investigations.
The contamination competes with CMB models with T/S = 10^{-2}--10^{-3}, close
to the intrinsic limit for a 15% portion of the sky (which is T/S ~ 10^{-3}).
If confirmed by future surveys with larger sky coverage, this gives interesting
perpectives for experiments, that, targeting selected low emission regions,
could reach this theoretical limit.


title: Brownian Motion in Planetary Migration

abstract:
  A residual planetesimal disk of mass 10-100 Earth masses remained in the
outer solar system following the birth of the giant planets, as implied by the
existence of the Oort cloud, coagulation requirements for Pluto, and
inefficiencies in planet formation. Upon gravitationally scattering
planetesimal debris, planets migrate. Orbital migration can lead to resonance
capture, as evidenced here in the Kuiper and asteroid belts, and abroad in
extra-solar systems. Finite sizes of planetesimals render migration stochastic
("noisy"). At fixed disk mass, larger (fewer) planetesimals generate more
noise. Extreme noise defeats resonance capture. We employ order-of-magnitude
physics to construct an analytic theory for how a planet's orbital semi-major
axis fluctuates in response to random planetesimal scatterings. To retain a
body in resonance, the planet's semi-major axis must not random walk a distance
greater than the resonant libration width. We translate this criterion into an
analytic formula for the retention efficiency of the resonance as a function of
system parameters, including planetesimal size. We verify our results with
tailored numerical simulations. Application of our theory reveals that capture
of Resonant Kuiper belt objects by a migrating Neptune remains effective if the
bulk of the primordial disk was locked in bodies having sizes < O(100) km and
if the fraction of disk mass in objects with sizes > 1000 km was less than a
few percent. Coagulation simulations produce a size distribution of primordial
planetesimals that easily satisfies these constraints. We conclude that
stochasticity did not interfere with, nor modify in any substantive way,
Neptune's ability to capture and retain Resonant Kuiper belt objects during its
migration.


title:
Evolution in the Halo Masses of Isolated Galaxies between z~1 and z~0:
  From DEEP2 to SDSS

abstract:
  We measure the evolution in the virial mass-to-light ratio (M_{200}/L_B) and
virial-to-stellar mass ratio (M_{200}/M_\ast) for isolated ~ L* galaxies
between z~1 and z~0 by combining data from the DEEP2 Galaxy Redshift Survey and
the Sloan Digital Sky Survey. Utilizing the motions of satellite galaxies
around isolated galaxies, we measure line-of-sight velocity dispersions and
derive dark matter halo virial masses for these host galaxies. At both epochs
the velocity dispersion of satellites correlates with host galaxy stellar mass,
\sigma\propto M_\ast^{0.4+/-0.1}, while the relation between satellite velocity
dispersion and host galaxy B-band luminosity may grow somewhat shallower from
\sigma\propto L_B^{0.6+/-0.1} at z~1 to \sigma\propto L_B^{0.4+/-0.1} at z~0.
The evolution in M_200/M_\ast from z~1 to z~0 displays a bimodality insofar as
host galaxies with stellar mass below M_\ast ~10^{11} M_Sun/h maintain a
constant ratio (the intrinsic increase is constrained to a factor of 1.1+/-0.7)
while host galaxies above M_\ast ~10^{11} M_Sun/h experience a factor of 4+/-3
increase in their virial-to-stellar mass ratio. This result can be easily
understood if galaxies below this stellar mass scale continue to form stars
while star formation in galaxies above this scale is quenched and the dark
matter halos of galaxies both above and below this scale grow in accordance
with LCDM cosmological simulations. Host galaxies that are red in U-B color
have larger satellite dispersions and hence reside on average in more massive
halos than blue galaxies at both z~1 and z~0. The redshift and host galaxy
stellar mass dependence of M_200/M_\ast agrees qualitatively with the
Millennium Run semi-analytic model of galaxy formation. (ABRIDGED)


title: Dust absorption along the line of sight for high-redshift objects

abstract:
  We estimate the optical depth distribution of dust present in absorption
systems along the line of sight of high redshift galaxies and the resulting
reddening. We characterize the probability distribution of the transmission to
a given redshift and the shape of the effective mean extinction law by means of
analytical estimates and Monte Carlo simulations. We present our results in a
format useful for applications to present samples of high redshift galaxies and
discuss the implications for observations with the James Webb Space Telescope.
Our most realistic model takes into account the metallicity evolution of Damped
Lyman Alpha absorbers and predicts that the effects of dust absorption are
modest: at redshift z \gtrsim 5 the transmission is above 0.8 at an emitted
wavelength \lambda_e = 0.14 \mu m with probability 90%. Therefore dust
obscuration along the line of sight will affect only marginally observations at
very high redshift.


title:
Testing the Disk-Locking Paradigm: An Association Between U-V Excess and
  Rotation in NGC 2264

abstract:
  We present some results from a UVI photometric study of a field in the young
open cluster NGC 2264 aimed, in part, at testing whether accretion in pre-main
sequence stars is linked to rotation. We confirm that U-V excess is well
correlated with H-alpha equivalent width for the stars in our sample. We show
that for the more massive stars in the cluster sample (roughly 0.4-1.2 M_sun)
there is also a significant association between U-V excess and rotation, in the
sense that slow rotators are more likely to show excess U-band emission and
variability. This constitutes significant new evidence in support of the
disk-locking paradigm.


title:
Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey
  of the Magellanic Clouds

abstract:
  The EROS-2 project was designed to test the hypothesis that massive compact
halo objects (the so-called ``machos'') could be a major component of the dark
matter halo of the Milky Way galaxy. To this end, EROS-2 monitored over 6.7
years $33\times10^6$ stars in the Magellanic clouds for microlensing events
caused by such objects. In this work, we use only a subsample of $7\times10^6$
bright stars spread over $84 \deg^2$ of the LMC and $9 \deg^2$ of the SMC. The
strategy of using only bright stars helps to discriminate against background
events due to variable stars and allows a simple determination of the effects
of source confusion (blending). The use of a large solid angle makes the survey
relatively insensitive to effects that could make the optical depth strongly
direction dependent. Using this sample of bright stars, only one candidate
event was found, whereas $\sim39$ events would have been expected if the Halo
were entirely populated by objects of mass $M\sim0.4M_{\odot}$. Combined with
the results of EROS-1, this implies that the optical depth toward the Large
Magellanic Cloud (\object{LMC}) due to such lenses is $\tau<0.36\times10^{-7}$
(95%CL), corresponding to a fraction of the halo mass of less than 8%. This
optical depth is considerably less than that measured by the MACHO
collaboration in the central region of the LMC. More generally, machos in the
mass range $0.6\times10^{-7}M_\odot<M<15M_{\odot}$ are ruled out as the primary
occupants of the Milky Way Halo.


title:
The Polarization of the Cosmic Microwave Background Due to Primordial
  Gravitational Waves

abstract:
  We review current observational constraints on the polarization of the Cosmic
Microwave Background (CMB), with a particular emphasis on detecting the
signature of primordial gravitational waves. We present an analytic solution to
the Polanarev approximation for CMB polarization produced by primordial
gravitational waves. This simplifies the calculation of the curl, or B-mode
power spectrum associated with gravitational waves during the epoch of
cosmological inflation. We compare our analytic method to existing numerical
methods and also make predictions for the sensitivity of upcoming CMB
polarization observations to the inflationary gravitational wave background. We
show that upcoming experiments should be able either detect the relic
gravitational wave background or completely rule out whole classes of
inflationary models.


title:
The Kinetic Sunyaev-Zel'dovich Effect from Patchy Reionization: the View
  from the Simulations

abstract:
  We present the first calculation of the kinetic Sunyaev-Zel'dovich (kSZ)
effect due to the inhomogeneus reionization of the universe based on detailed
large-scale radiative transfer simulations of reionization. The resulting sky
power spectra peak at l=2000-8000 with maximum values of
l(l+1)C_l/(2pi)_{max}~4-7x10^{-13}. The scale roughly corresponds to the
typical ionized bubble sizes observed in our simulations, of ~5-20 Mpc. The kSZ
anisotropy signal from reionization dominates the primary CMB signal above
l=3000. At large scales the patchy kSZ signal depends only on the source
efficiencies. It is higher when sources are more efficient at producing
ionizing photons, since such sources produce larger ionized regions, on
average, than less efficient sources. The introduction of sub-grid gas clumping
in the radiative transfer simulations produce significantly more power at small
scales, but has little effect at large scales. The patchy reionization kSZ
signal is dominated by the post-reionization signal from fully-ionized gas, but
the two contributions are of similar order at scales l~3000-10^4, indicating
that the kSZ anisotropies from reionization are an important component of the
total kSZ signal at these scales.


title: Stability Limits in Extra-solar Planetary Systems

abstract:
  Two types of stability boundaries exist for any planetary system consisting
of one star and two planets. Lagrange stability requires that the planets
remain bound to the star, conserves the ordering of the distance from the star,
and limits the variations of orbital elements like semi-major axis and
eccentricity. Hill stability only requires that the ordering of the planets
remain constant; the outer planet may escape to infinity. A simple formula
defines a region in orbital element space that is guaranteed to be Hill stable,
although Hill stable orbits may lie outside the region as well. No analytic
criteria describe Lagrange stability. We compare the results of 1000 numerical
simulations of planetary systems similar to 47 UMa and HD 12661 with these two
types of boundaries. All cases are consistent with the analytic criterion for
Hill stability. Moreover, the numerically determined Lagrange boundary lies
close to the analytic boundary for Hill stability. This result suggests an
analytic formulation that may describe the criterion for Lagrange stability.


title:
Atomic and Molecular Opacities for Brown Dwarf and Giant Planet
  Atmospheres

abstract:
  We present a comprehensive description of the theory and practice of opacity
calculations from the infrared to the ultraviolet needed to generate models of
the atmospheres of brown dwarfs and extrasolar giant planets. Methods for using
existing line lists and spectroscopic databases in disparate formats are
presented and plots of the resulting absorptive opacities versus wavelength for
the most important molecules and atoms at representative temperature/pressure
points are provided. Electronic, ro-vibrational, bound-free, bound-bound,
free-free, and collision-induced transitions and monochromatic opacities are
derived, discussed, and analyzed. The species addressed include the alkali
metals, iron, heavy metal oxides, metal hydrides, $H_2$, $H_2O$, $CH_4$, $CO$,
$NH_3$, $H_2S$, $PH_3$, and representative grains. [Abridged]


title: On the Origin of HD149026b

abstract:
  The high density of the close-in extrasolar planet HD149026b suggests the
presence of a huge core in the planet, which challenges planet formation
theory. We first derive constraints on the amount of heavy elements and
hydrogen/helium present in the planet: We find that preferred values of the
core mass are between 50 and 80 M_E. We then investigate the possibility of
subcritical core accretion as envisioned for Uranus and Neptune and find that
the subcritical accretion scenario is unlikely in the case of HD149026b for at
least two reasons: (i) Subcritical planets are such that the ratio of their
core mass to their total mass is above ~0.7, in contradiction with constraints
for all but the most extreme interior models of HD149026b; (ii) High accretion
rates and large isolation mass required for the formation of a subcritical core
of 30 M_E are possible only at specific orbital distances in a disk with a
surface density of dust equal to at least 10 times that of the minimum mass
solar nebula. This value climbs to 30 when considering a 50 M_E core. These
facts point toward two main routes for the formation of this planet: (i) Gas
accretion that is limited by a slow viscous inflow of gas in an evaporating
disk; (ii) A significant modification of the composition of the planet after as
accretion has stopped. These two routes are not mutually exclusive.
Illustrating the second route, we show that for a wide range of impact
parameters, giant impacts lead to a loss of the gas component of the planet and
thus may lead to planets that are highly enriched in heavy elements. In the
giant impact scenario, we expect an outer giant planet to be present.
Observational studies by imaging, astrometry and long term interferometry of
this system are needed to better narrow down the ensemble of possibilities.


title:
Helium-rich thermonuclear bursts and the distance to the
  accretion-powered millisecond pulsar SAX J1808.4-3658

abstract:
  We analysed Rossi X-ray Timing Explorer observations of the accretion-powered
401 Hz pulsar SAX J1808.4-3658, in order to precisely determine the source
distance. While the fluences for the five transient outbursts observed from
1996 were constant to within the uncertainties, the outburst interval varied
signficantly, so that the time-averaged flux (and accretion rate) decreased by
around 40%. By equating the time-averaged X-ray flux with the expected mass
transfer rate from gravitational radiation, we derived a lower limit on the
distance of 3.4 kpc. Combined with an upper limit from assuming that the four
radius-expansion thermonuclear bursts observed during the 2002 October outburst
reached at most the Eddington limit for a pure He atmosphere, we found that the
probable distance range for the source is 3.4-3.6 kpc. The implied inclination,
based on the optical/IR properties of the counterpart, is i<~30 degrees.
  We compared the properties of the bursts with an ignition model. The time
between bursts was long enough for hot CNO burning to significantly deplete the
accreted hydrogen, so that ignition occurred in a pure helium layer underlying
a stable hydrogen burning shell. This is the first time that this burning
regime has been securely observationally identified. The observed energetics of
the bursts give a mean hydrogen fraction at ignition of <X> approx. 0.1, and
require that the accreted hydrogen fraction X_0 and the CNO metallicity Z_CNO
are related by Z_CNO approx. 0.03(X_0/0.7)^2. We show that in this burning
regime, a measurement of the burst recurrence time and energetics allows the
local accretion rate onto the star to be determined independently of the
accreted composition, giving a new method for estimating the source distance
which is in good agreement with our other estimates.


title:
Magnetic burial and the harmonic content of millisecond oscillations in
  thermonuclear X-ray bursts

abstract:
  Matter accreting onto the magnetic poles of a neutron star spreads under
gravity towards the magnetic equator, burying the polar magnetic field and
compressing it into a narrow equatorial belt. Steady-state, Grad-Shafranov
calculations with a self-consistent mass-flux distribution (and a
semi-quantitative treatment of Ohmic diffusion) show that, for $\Ma \gtrsim
10^{-5}\Msun$, the maximum field strength and latitudinal half-width of the
equatorial magnetic belt are $B_{\rm max} = 5.6\times 10^{15}
(\Ma/10^{-4}\Msun)^{0.32}$ G and $\Delta\theta = \max[3^{\circ}
(\Ma/10^{-4}\Msun)^{-1.5},3^{\circ} (\Ma/10^{-4}\Msun)^{0.5}(\dot{M}_{\rm
a}/10^{-8}\Msun {\rm yr}^{-1})^{-0.5}]$ respectively, where $\Ma$ is the total
accreted mass and $\dot{M}_{\rm a}$ is the accretion rate. It is shown that the
belt prevents north-south heat transport by conduction, convection, radiation,
and ageostrophic shear. This may explain why millisecond oscillations observed
in the tails of thermonuclear (type I) X-ray bursts in low-mass X-ray binaries
are highly sinusoidal: the thermonuclear flame is sequestered in the magnetic
hemisphere which ignites first. The model is also consistent with the
occasional occurrence of closely spaced pairs of bursts. Time-dependent,
ideal-magnetohydrodynamic simulations confirm that the equatorial belt is not
disrupted by Parker and interchange instabilities.


title:
The Origin Magnetars: the role of anisotropic neutron superfluid of
  neutron stars

abstract:
  We estimate the strength of the induced magnetic field due to the total
induced magnetic moment of the anisotropic ($^3PF^2$) neutron superfluid
interior of neutron stars. The induced magnetic field of the neutron stars is
found as follows. $B^{(in)} = \frac{\eta}{{T_7 - \eta}}B^{(0)}
,\begin{array}{*{20}c}{} & {\eta =} \ \end{array}\frac{{m(^3 P_2
)}}{{0.1m_{Sun}}}R_{NS,6}^{- 3} $ ($T_7$ denotes the interior temperature of
the neutron star in unit of 10$^7$ K). The induced magnetic field will
gradually increase with the temperature of the neutron star decreasing in their
late evolutionary stage. A magnetar may appear in a condition when $T_7 \to
\eta$. The upper limit of the induced magnetic field of $^3P^2$ superfluid is
$3.35 \time 10^{14} \eta$.


title: MHD disc winds

abstract:
  This is a doctorate level lecture on the physics of accretion discs driving
magnetically self-confined jets, usually referred to in the literature as disc
winds. I will first review the governing magnetohydrodynamic equations and then
discuss their physical content. At that level, necessary conditions to drive
jets from keplerian accretion discs can already be derived. These conditions
are validated with self-similar calculations of accretion-ejection structures.
In a second part, I will critically discuss the biases introduced when using
self-similarity as well as some other questions such as: Are these systems
really unstable? Can a standard accretion disc provide the conditions to launch
jets in its innermost parts? What is the difference between X-winds and
disc-winds? Finally, the magnetic interaction between a protostar and its
circumstellar disc will be discussed with a focus on stellar spin down.


title: Are peculiar Wolf-Rayet Stars of type WN8 Thorne-Zytkow Objects?

abstract:
  Most population I Wolf-Rayet (WR) stars are the He-rich descendants of the
most massive stars (M_i = 25 - 100 M_sun). Evidence has been accumulating over
the years that among all pop I WR stars, those of the relatively cool, N-rich
subtype "WN8" are among the most peculiar: 1. They tend to be runaways, with
large space velocity and/or avoid clusters. 2. Unlike their equally luminous
WN6,7 cousins, only a very small number of WN8 stars are known to belong to a
close binary with an OB companion. 3. They are the systematically most highly
stochastically variable among all (single) WR stars. Taken together, these
suggest that many WN8 stars may originally have been in close binaries (like
half of all stars), in which the original primary exploded as a supernova,
leaving behind a very close binary containing a massive star with a neutron
star/black hole companion (like Cyg X-3). When the massive remaining star
evolved in turn, it engulfed and eventually swallowed the compact companion,
leading to the presently puffed-up, variable WN8 star. Such stars could fall in
the realm of the exotic Thorne-Zytkow objects.


title: The Chemical Composition of Red Giants, AGB Stars and Planetary Nebulae

abstract:
  The determinations of element abundances in red-giant stars and in particular
in AGB stars are reviewed and the resulting abundances are compared with those
obtained for planetary nebulae in the Galaxy and in nearby galaxies. The
problems, possibilities and implications of such comparisons when estimating
yields from low-mass and intermediate-mass stars are illustrated and commented
on.


title:
On the Possible Properties of Small and Cold Extrasolar Planets: Is
  OGLE-2005-BLG-390Lb Entirely Frozen?

abstract:
  Extrasolar planets as light as a few Earths are now being detected. Such
planets are likely not gas or ice giants. Here, we present a study on the
possible properties of the small and cold extrasolar planets, applied to the
case of the recently discovered planet OGLE-2005-BLG-390Lb (Beaulieu et al.
2006). This planet (5.5[+5.5/-2.7] Earth masses) orbits
2.6[+1.5/-0.6]-astronomical units away from an old M-type star of the Galactic
Bulge. The planet should be entirely frozen given the low surface temperature
(35 to 47 K). However, depending on the rock-to-ice mass ratio in the planet,
the radiogenic heating could be sufficient to make the existence of liquid
water within an icy crust possible. This possibility is estimated as a function
of the planetary mass and the illumination received from the parent star, both
being strongly related by the observational constraints. The results are
presented for water-poor and water-rich planets. We find that no oceans can be
present in any cases at 9-10 Gyr, a typical age for a star of the Bulge.
However, we find that, in the past when the planet was < 5-billion-years old,
liquid water was likely present below an icy surface. Nevertheless, the planet
is now likely to be entirely frozen.


title: High-gravity central stars

abstract:
  NLTE spectral analyses of high-gravity central stars by means of
state-of-the-art model atmosphere techniques provide information about the
precursor AGB stars. The hydrogen-deficient post-AGB stars allow investigations
on the intershell matter which is apparently exhibited at the stellar surface.
We summarize recent results from imaging, spectroscopy, and spectropolarimetry.


title: Galaxy morphology and evolution from SWAN Adaptive Optics imaging

abstract:
  We present the results from adaptive optics (AO) assisted imaging in the Ks
band of an area of 15 arcmin^2 for SWAN (Survey of a Wide Area with NACO). We
derive the high resolution near-IR morphology of ~400 galaxies up to Ks~23.5 in
the first 21 SWAN fields around bright guide stars, carefully taking into
account the survey selection effects and using an accurate treatment of the
anisoplanatic AO PSF. The detected galaxies are sorted into two morphological
classes according to their Sersic index. The extracted morphological properties
and number counts of the galaxies are compared with the predictions of
different galaxy formation and evolution models, both for the whole galaxy
population and separately for late-type and early-type galaxies. This is one of
the first times such a comparison has been done in the near-IR, as AO
observations and accurate PSF modeling are needed to obtain reliable
morphological classification of faint field galaxies at these wavelengths. For
early-type galaxies we find that a pure luminosity evolution model, without
evidence for relevant number and size evolution, better reproduces the observed
properties of our Ks-selected sample than current semi-analytic models based on
the hierarchical picture of galaxy formation. In particular, we find that the
observed flattening of elliptical galaxy counts at Ks~20 is quantitatively in
good agreement with the prediction of the pure luminosity evolution model that
was calculated prior to the observation. For late-type galaxies, while both
models are able to reproduce the number counts, we find some hints of a
possible size growth. These results demonstrate the unique power of AO
observations to derive high resolution details of faint galaxies' morphology in
the near-IR and drive studies of galaxy evolution.


title: Terrestrial Planet Formation Surrounding Close Binary Stars

abstract:
  Disk material has been observed around both components of some young close
binary star systems. It has been shown that if planets form at the right places
within such disks, they can remain dynamically stable for very long times.
Herein, we numerically simulate the late stages of terrestrial planet growth in
circumbinary disks around 'close' binary star systems with stellar separations
between 0.05 AU and 0.4 AU and binary eccentricities up to 0.8. In each
simulation, the sum of the masses of the two stars is 1 solar mass, and giant
planets are included. Our results are statistically compared to a set of planet
formation simulations in the Sun-Jupiter-Saturn system that begin with
essentially the same initial disk of protoplanets. The planetary systems formed
around binaries with apastron distances less than ~ 0.2 AU are very similar to
those around single stars, whereas those with larger maximum separations tend
to be sparcer, with fewer planets, especially interior to 1 AU. We also provide
formulae that can be used to scale results of planetary accretion simulations
to various systems with different total stellar mass, disk sizes, and
planetesimal masses and densities.


title:
A Putative Early-Type Host Galaxy for GRB 060502B: Implications for the
  Progenitors of Short-Duration Hard-Spectrum Bursts

abstract:
  Starting with the first detection of an afterglow from a short-duration
hard-spectrum gamma-ray burst (SHB) by Swift last year, a growing body of
evidence has suggested that SHBs are associated with an older and
lower-redshift galactic population than long-soft GRBs and, in a few cases,
with large (>~ 10 kpc) projected offsets from the centers of their putative
host galaxies. Here we present observations of the field of GRB 060502B, a SHB
detected by Swift and localized by the X-ray Telescope (XRT). We find a massive
red galaxy at a redshift of z=0.287 at an angular distance of 17.1 arcsec from
our revised XRT position. Using associative and probabilistic arguments we
suggest that this galaxy hosted the progenitor of GRB 060502B. If true, this
offset would correspond to a physical displacement of 73 +- 19 kpc in
projection, about twice the largest offset inferred for any SHB to date and
almost an order of magnitude larger than a typical long-soft burst offset.
Spectra and modeling of the star-formation history of this possible host show
it to have undergone a large ancient starburst. If the progenitor of GRB
060502B was formed in this starburst episode, the time of the GRB explosion
since birth is tau = 1.3 +- 0.2 Gyr and the minimum kick velocity of the SHB
progenitor is v_kick = 55 +- 15 km/s.


title:
Gravitational Radiation from Standing Accretion Shock Instability in
  Core-Collapse Supernovae

abstract:
  We present the results of numerical experiments, in which we study how the
asphericities induced by the growth of the standing accretion shock instability
(SASI) produce the gravitational waveforms in the postbounce phase of
core-collapse supernovae. To obtain the neutrino-driven explosions, we
parameterize the neutrino fluxes emitted from the central protoneutron star and
approximate the neutrino transfer by a light-bulb scheme. We find that the
waveforms due to the anisotropic neutrino emissions show the monotonic increase
with time, whose amplitudes are up to two order-of-magnitudes larger than the
ones from the convective matter motions outside the protoneutron stars.
  We point out that the amplitudes begin to become larger when the growth of
the SASI enters the nonlinear phase, in which the deformation of the shocks and
the neutrino anisotropy become large. From the spectrum analysis of the
waveforms, we find that the amplitudes from the neutrinos are dominant over the
ones from the matter motions at the frequency below $\sim 100$ Hz, which are
suggested to be within the detection limits of the detectors in the next
generation such as LCGT and the advanced LIGO for a supernova at 10 kpc.
  As a contribution to the gravitational wave background, we show that the
amplitudes from this source could be larger at the frequency above $\sim$ 1 Hz
than the primordial gravitational wave backgrounds, but unfortunately,
invisible to the proposed space-based detectors.


title: Spectroscopic binaries with components of similar mass

abstract:
  The assertion that there is an intrinsic excess of binaries with mass ratios
q \simeq 1 - the twin hypothesis - is investigated. A strong version of this
hypothesis (H_s), due to Lucy & Ricco (1979) and Tokovinin (2000), refers to a
narrow peak in the distribution function psi(q) for q \ga 0.95. A weak version
(H_w), due to Halbwachs et al. (2003), refers to a broad peak for q \ga 0.8.
Current data on SB2's is analysed and H_s is found to be statistically
significant for a sample restricted to orbits of high precision. But claims
that H_s is significant for binaries with special characteristics are not
confirmed since the sample sizes are well below the minimum required for a
reliable test. With regard to H_w, additional observational evidence is not
presented, but evidence to the contrary in the form of Hogeveen's (1992b) model
of biased sampling with psi \propto q^{-2} is criticized. Specifically, his
success in thus fitting catalogued data depends on implausible assumptions
about the research methodologies of binary-star spectroscopists.


title:
The X-ray Properties of Active Galactic Nuclei with Double-Peaked Balmer
  Lines

abstract:
  Double-peaked Balmer-line profiles originate in the accretion disks of a few
percent of optically selected AGN. The reasons behind the strong low-ionization
line emission from the accretion disks of these objects is still uncertain. In
this paper, we characterize the X-ray properties of 39 double-peaked Balmer
line AGN, 29 from the Sloan Digital Sky Survey and 10 low optical-luminosity
double-peaked emitters from earlier radio-selected samples. We find that the
UV-to-X-ray slope of radio-quiet (RQ) double-peaked emitters as a class does
not differ substantially from that of normal RQ AGN with similar UV
monochromatic luminosity. The radio-loud (RL) double-peaked emitters, with the
exception of LINER galaxies, are more luminous in the X-rays than RQ AGN, as
has been observed for other RL AGN with single-peaked profiles. The X-ray
spectral shapes of double-peaked emitters, measured by their hardness ratios or
power-law photon indices, are also largely consistent with those of normal AGN
of similar radio-loudness. In practically all cases studied here, external
illumination of the accretion disk is necessary to produce the Balmer-line
emission, as the gravitational energy released locally in the disk by viscous
stresses is insufficient to produce lines of the observed strength. In the
Appendix we study the variability of Mrk 926, a double-peaked emitter with
several observations in the optical and X-ray bands.


title: Why anthropic reasoning cannot predict Lambda

abstract:
  We revisit anthropic arguments purporting to explain the measured value of
the cosmological constant. We argue that different ways of assigning
probabilities to candidate universes lead to totally different anthropic
predictions. As an explicit example, we show that weighting different universes
by the total number of possible observations leads to an extremely small
probability for observing a value of Lambda equal to or greater than what we
now measure. We conclude that anthropic reasoning within the framework of
probability as frequency is ill-defined and that in the absence of a
fundamental motivation for selecting one weighting scheme over another the
anthropic principle cannot be used to explain the value of Lambda, nor, likely,
any other physical parameters.


title: X-ray Emission from Extragalactic Jets

abstract:
  This review focuses on the X-ray emission processes of extra-galactic jets on
scales resolvable by the sub arcsec resolution of the Chandra X-ray
Observatory. It is divided into 4 parts. The introductory chapter reviews the
classical problems for jets, as well as those associated directly with the
X-ray emission. Throughout this section, we deal with the dualisms of low
powered radio sources versus high powered radio galaxies and quasars;
synchrotron models versus inverse Compton models; and the distinction between
the relativistic plasma responsible for the received radiation and the medium
responsible for the transport of energy down the jet. The second part collects
the observational and inferred parameters for the currently detected X-ray jets
and attempts to put their relative sizes and luminosities in perspective. In
part 3, we first give the relevant radio and optical jet characteristics, and
then examine the details of the X-ray data and how they can be related to
various jet attributes. The last section is devoted to a critique of the two
non-thermal emission processes and to prospects for progress in our
understanding of jets.


title: Swift, RXTE, and INTEGRAL observation of Swift J1922.7-1716

abstract:
  We report the results of analyzing Swift, RossiXTE, and INTEGRAL data of
Swift J1922.7-1716, a likely transient X-ray source discovered by Swift/BAT.
Both the fast variability measured by the RXTE/PCA and the combined Swift/XRT,
RXTE/PCA, and INTEGRAL/ISGRI (0.5-100 keV) energy spectrum suggest that the
system is a neutron-star low-mass X-ray binary or a black-hole candidate at low
accretion levels. The non-simultaneous spectra are consistent with the same
spectral shape and flux, suggesting little variability over the period July to
October 2005, but the analysis of archival INTEGRAL data shows that the source
was not detected in 2003-2004, suggesting a transient or strongly variable
behavior.


title:
A High Order Godunov Scheme with Constrained Transport and Adaptive Mesh
  Refinement for Astrophysical MHD

abstract:
  In this paper, we present a new method to perform numerical simulations of
astrophysical MHD flows using the Adaptive Mesh Refinement framework and
Constrained Transport. The algorithm is based on a previous work in which the
MUSCL--Hancock scheme was used to evolve the induction equation. In this paper,
we detail the extension of this scheme to the full MHD equations and discuss
its properties. Through a series of test problems, we illustrate the
performances of this new code using two different MHD Riemann solvers
(Lax-Friedrich and Roe) and the need of the Adaptive Mesh Refinement
capabilities in some cases. Finally, we show its versatility by applying it to
two completely different astrophysical situations well studied in the past
years: the growth of the magnetorotational instability in the shearing box and
the collapse of magnetized cloud cores. We have implemented this new Godunov
scheme to solve the ideal MHD equations in the AMR code RAMSES. It results in a
powerful tool that can be applied to a great variety of astrophysical problems,
ranging from galaxies formation in the early universe to high resolution
studies of molecular cloud collapse in our galaxy.


title:
The Influence of Mass and Environment on the Evolution of Early-Type
  Galaxies

abstract:
  We report on a uniform comparative analysis of the fundamental parameters of
early-type galaxies at z~1 down to a well defined magnitude limit (M_B\leq
-20.0 in the field and M_B\leq -20.5 in the clusters). The changes in the M/L_B
ratio from z~1 to today are larger for lower mass galaxies in all environments,
and are similar in the field and in the clusters for galaxies with the same
mass. By deriving ages from the M}/L_B ratio, we estimate the formation
redshift for early-type galaxies as a function of galaxy mass and environment.
We find that the age of early-type galaxies increases with galaxy mass
(downsizing) in all environments, and that cluster galaxies appear to have the
same age within 5% as field galaxies at any given galaxy mass. The first result
confirms similar ones obtained by other means, while the second one is
controversial. The most recent incarnation of the hierarchical models of galaxy
formation and evolution is capable of explaining the first result, but predicts
that cluster galaxies should be older than field galaxies. We also find a total
lack of massive early--type galaxies M>3 10^{11} M_{\sun}) with a formation
redshift smaller than 2, which cannot be due to selection effects.


title:
Resolving and probing the circumstellar disk of the Herbig Ae star MWC
  480 at 1.4 mm: Evolved dust?

abstract:
  We present high resolution 0.45" x 0.32" observations from the BIMA array
toward the Herbig Ae system MWC 480 in the lambda = 1.4 mm dust continuum. We
resolve a circumstellar disk of radius ~170 AU and constrain the disk
parameters by comparing the observations to flat disk models. These results
show that the typical fit parameters of the disk, such as the mass, Md ~
0.04-0.18 Mo, and the surface density power law index, p=0.5 or 1, are
comparable to those of the lower mass T Tauri stars. The dust in the MWC 480
disk can be modeled as processed dust material (beta ~ 0.8), similar to the
Herbig Ae star CQ Tau disk; the fitted disk parameters are also consistent with
less-evolved dust (beta ~ 1.2). The possibility of grain growth in the MWC 480
circumstellar disk is supported by the acceptable fits with beta ~ 0.8. The
surface density power-law profiles of p=0.5 and p=1 can be easily fit to the
MWC 480 disk; however, a surface density power-law profile similiar to the
minimum mass solar nebula model p=1.5 is ruled out at an 80% confidence level.


title:
Limits on the high-energy gamma and neutrino fluxes from the SGR 1806-20
  giant flare of December 27th, 2004 with the AMANDA-II detector

abstract:
  On December 27th 2004, a giant gamma flare from the Soft Gamma-ray Repeater
1806-20 saturated many satellite gamma-ray detectors. This event was by more
than two orders of magnitude the brightest cosmic transient ever observed. If
the gamma emission extends up to TeV energies with a hard power law energy
spectrum, photo-produced muons could be observed in surface and underground
arrays. Moreover, high-energy neutrinos could have been produced during the SGR
giant flare if there were substantial baryonic outflow from the magnetar. These
high-energy neutrinos would have also produced muons in an underground array.
AMANDA-II was used to search for downgoing muons indicative of high-energy
gammas and/or neutrinos. The data revealed no significant signal. The upper
limit on the gamma flux at 90% CL is dN/dE < 0.05 (0.5) TeV^-1 m^-2 s^-1 for
gamma=-1.47 (-2). Similarly, we set limits on the normalization constant of the
high-energy neutrino emission of 0.4 (6.1) TeV^-1 m^-2 s^-1 for gamma=-1.47
(-2).


title: 21 cm fluctuations from inhomogeneous X-ray heating before reionization

abstract:
  Many models of early structure formation predict a period of heating
immediately preceding reionization, when X-rays raise the gas temperature above
that of the cosmic microwave background. These X-rays are often assumed to heat
the intergalactic medium (IGM) uniformly, but in reality they will heat the gas
more strongly closer to the sources. We develop a framework for calculating
fluctuations in the 21 cm brightness temperature that originate from this
spatial variation in the heating rate. High-redshift sources are highly
clustered, leading to significant gas temperature fluctuations (with fractional
variations ~40%, peaking on k~0.1 Mpc^{-1} scales). This induces a distinctive
peak-trough structure in the angle-averaged 21 cm power spectrum, which may be
accessible to the proposed Square Kilometre Array. This signal reaches the ~10
mK level, and is stronger than that induced by Lyman alpha flux fluctuations.
As well as probing the thermal evolution of the IGM before reionization, this
21 cm signal contains information about the spectra of the first X-ray sources.
Finally, we consider disentangling temperature, density and Lyman alpha flux
fluctuations as functions of redshift.


title:
Structure and Evolution of Nearby Stars with Planets II. Physical
  Properties of ~1000 Cool Stars from the SPOCS Catalog

abstract:
  We derive detailed theoretical models for 1074 nearby stars from the SPOCS
(Spectroscopic Properties of Cool Stars) Catalog. The California and Carnegie
Planet Search has obtained high-quality echelle spectra of over 1000 nearby
stars taken with the Hamilton spectrograph at Lick Observatory, the HIRES
spectrograph at Keck, and UCLES at the Anglo Australian Observatory. A uniform
analysis of the high-resolution spectra has yielded precise stellar parameters,
enabling systematic error analyses and accurate theoretical stellar modeling.
We have created a large database of theoretical stellar evolution tracks using
the Yale Stellar Evolution Code (YREC) to match the observed parameters of the
SPOCS stars. Our very dense grids of evolutionary tracks eliminate the need for
interpolation between stellar evolutionary tracks and allow precise
determinations of physical stellar parameters (mass, age, radius, size and mass
of the convective zone, etc.). Combining our stellar models with the observed
stellar atmospheric parameters and uncertainties, we compute the likelihood for
each set of stellar model parameters separated by uniform time steps along the
stellar evolutionary tracks. The computed likelihoods are used for a Bayesian
analysis to derive posterior probability distribution functions for the
physical stellar parameters of interest. We provide a catalog of physical
parameters for 1074 stars that are based on a uniform set of high quality
spectral observations, a uniform spectral reduction procedure, and a uniform
set of stellar evolutionary models. We explore this catalog for various
possible correlations between stellar and planetary properties, which may help
constrain the formation and dynamical histories of other planetary systems.


title:
Eclipsing binaries suitable for distance determination in the Andromeda
  galaxy

abstract:
  The Local Group galaxies constitute a fundamental step in the definition of
cosmic distance scale. Therefore, obtaining accurate distance determinations to
the galaxies in the Local Group, and notably to the Andromeda Galaxy (M31), is
essential to determining the age and evolution of the Universe. With this
ultimate goal in mind, we started a project to use eclipsing binaries as
distance indicators to M31. Eclipsing binaries have been proved to yield direct
and precise distances that are essentially assumption free. To do so,
high-quality photometric and spectroscopic data are needed. As a first step in
the project, broad band photometry (in Johnson B and V) has been obtained in a
region (34'x34') at the North-Eastern quadrant of the galaxy over 5 years. The
data, containing more than 250 observations per filter, have been reduced by
means of the so-called difference image analysis technique and the DAOPHOT
program. A catalog with 236238 objects with photometry in both B and V
passbands has been obtained. The catalog is the deepest (V<25.5 mag) obtained
so far in the studied region and contains 3964 identified variable stars, with
437 eclipsing binaries and 416 Cepheids. The most suitable eclipsing binary
candidates for distance determination have been selected according to their
brightness and from the modelling of the obtained light curves. The resulting
sample includes 24 targets with photometric errors around 0.01 mag. Detailed
analysis (including spectroscopy) of some 5-10 of these eclipsing systems
should result in a distance determination to M31 with a relative uncertainty of
2-3% and essentially free from systematic errors, thus representing the most
accurate and reliable determination to date.


title: Satellite Systems around Galaxies in Hydrodynamic Simulations

abstract:
  We investigate the properties of satellite galaxies formed in N-body/SPH
simulations of galaxy formation in the $\Lambda$CDM cosmology. The simulations
include the main physical effects thought to be important in galaxy formation
and, in several cases, produce realistic spiral discs. In total, a sample of 9
galaxies of luminosity comparable to the Milky Way was obtained. At magnitudes
brighter than the resolution limit, $M_V=-12$, the luminosity function of the
satellite galaxies in the simulations is in excellent agreement with data for
the Local Group. The radial number density profile of the model satellites, as
well as their gas fractions also match observations very well. In agreement
with previous N-body studies, we find that the satellites tend to be
distributed in highly flattened configurations whose major axis is aligned with
the major axis of the (generally triaxial) dark halo. In 2 out of 3 systems
with sufficiently large satellite populations, the satellite system is nearly
perpendicular to the plane of the galactic disc, a configuration analogous to
that observed in the Milk Way. The discs themselves are perpendicular to the
minor axis of their host halos in the inner parts, and the correlation between
the orientation of the galaxy and the shape of the halo persists even out to
the virial radius. However, in one case the disc's minor axis ends up, at the
virial radius, perpendicular to the minor axis of the halo. The angular momenta
of the galaxies and their host halo tend to be well aligned.


title: Luminosity Function of Faint Globular Clusters in M87

abstract:
  We present the luminosity function to very faint magnitudes for the globular
clusters in M87, based on a 30 orbit \textit{Hubble Space Telescope (HST)}
WFPC2 imaging program. The very deep images and corresponding improved false
source rejection allow us to probe the mass function further beyond the
turnover than has been done before. We compare our luminosity function to those
that have been observed in the past, and confirm the similarity of the turnover
luminosity between M87 and the Milky Way. We also find with high statistical
significance that the M87 luminosity function is broader than that of the Milky
Way. We discuss how determining the mass function of the cluster system to low
masses can constrain theoretical models of the dynamical evolution of globular
cluster systems. Our mass function is consistent with the dependence of mass
loss on the initial cluster mass given by classical evaporation, and somewhat
inconsistent with newer proposals that have a shallower mass dependence. In
addition, the rate of mass loss is consistent with standard evaporation models,
and not with the much higher rates proposed by some recent studies of very
young cluster systems. We also find that the mass-size relation has very little
slope, indicating that there is almost no increase in the size of a cluster
with increasing mass.


title: A Strong-Lens Survey in AEGIS: the influence of large scale structure

abstract:
  We report on the results of a visual search for galaxy-scale strong
gravitational lenses over 650 arcmin^2 of HST/ACS imaging in the DEEP2-EGS
field. In addition to a previously-known Einstein Cross (the "Cross," HST
J141735+52264, with z_lens=0.8106 and a published z_source=3.40), we identify
two new strong galaxy-galaxy lenses with multiple extended arcs. The first, HST
J141820+52361 (the ``Dewdrop''; z_lens=0.5798, lenses two distinct extended
sources into two pairs of arcs z_source=0.while), 9818 the second, HST
J141833+52435 (the ``Anchor''; z_lens=0.4625), produces a single pair of arcs
(source redshift not yet known). All three definite lenses are fit well by
simple singular isothermal ellipsoid models including external shear. Using the
three-dimensional line-of-sight (LOS) information on galaxies from the DEEP2
data, we calculate the convergence and shear contributions, assuming singular
isothermal sphere halos truncated at 200 h^-1 kpc. These are also compared
against three-dimensional local-density estimates. We find that even strong
lenses in demonstrably underdense local environments may be considerably
affected by LOS contributions, which in turn, may be underestimates of the
effect of large scale structure.


title: The Hubble time inferred from 10 time-delay lenses

abstract:
  We present a simultaneous analysis of 10 galaxy lenses having time-delay
measurements. For each lens we derive a detailed free-form mass map, with
uncertainties, and with the additional requirement of a shared value of the
Hubble parameter across all the lenses. We test the prior involved in the lens
reconstruction against a galaxy-formation simulation. Assuming a concordance
cosmology, we obtain 1/H_0 = 13.5 (+2.5/-1.3) Gyr


title: Collisional Particle Disks

abstract:
  We present a new, simple, fast algorithm to numerically evolve disks of
inelastically colliding particles surrounding a central star. Our algorithm
adds negligible computational cost to the fastest existing collisionless N-body
codes, and can be used to simulate, for the first time, the interaction of
planets with disks over many viscous times. Though the algorithm is implemented
in two dimensions-i.e., the motions of bodies need only be tracked in a
plane-it captures the behavior of fully three-dimensional disks in which
collisions maintain inclinations that are comparable to random eccentricities.
We subject the algorithm to a battery of tests for the case of an isolated,
narrow, circular ring. Numerical simulations agree with analytic theory with
regards to how particles' random velocities equilibrate; how the ring viscously
spreads; and how energy dissipation, angular momentum transport, and material
transport are connected. We derive and measure the critical value of the
coefficient of restitution above which viscous stirring dominates inelastic
damping and the particles' velocity dispersion runs away.


title: AEGIS: The Diversity of Bright Near-IR Selected Distant Red Galaxies

abstract:
  We use deep and wide near infrared (NIR) imaging from the Palomar telescope
combined with DEEP2 spectroscopy and Hubble Space Telescope (HST) and Chandra
Space Telescope imaging to investigate the nature of galaxies that are red in
NIR colors. We locate these `distant red galaxies' (DRGs) through the color cut
(J-K)_{vega} > 2.3 over 0.7 deg^{2}, where we find 1010 DRG candidates down to
K_s = 20.5. We combine 95 high quality spectroscopic redshifts with photometric
redshifts from BRIJK photometry to determine the redshift and stellar mass
distributions for these systems, and morphological/structural and X-ray
properties for 107 DRGs in the Extended Groth Strip. We find that many bright
(J-K)_{vega}>2.3 galaxies with K_s<20.5 are at redshifts z<2, with 64% between
1<z<2. The stellar mass distributions for these galaxies is broad, ranging from
10^{9}-10^{12} M_solar, but with most z>2 systems massive with M_*>10^{11}
M_solar. HST imaging shows that the structural properties and morphologies of
DRGs are also diverse, with the majority elliptical/compact (57%), and the
remainder edge-on spirals (7%), and peculiar galaxies (29%). The DRGs at z <
1.4 with high quality spectroscopic redshifts are generally compact, with small
half light radii, and span a range in rest-frame optical properties. The
spectral energy distributions for these objects differ from higher redshift
DRGs: they are bluer by one magnitude in observed (I-J) color. A pure IR color
selection of high redshift populations is not sufficient to identify unique
populations, and other colors, or spectroscopic redshifts are needed to produce
homogeneous samples.


title: Imbalanced Strong MHD Turbulence

abstract:
  We present a phenomenological model of imbalanced MHD turbulence in an
incompressible magnetofluid. The steady-state cascades, of waves traveling in
opposite directions along the mean magnetic field, carry unequal energy fluxes
to small length scales, where they decay due to viscous and resistive
dissipation. The inertial-range scalings are well-understood when both cascades
are weak. We study the case when both cascades are, in a sense, strong. The
inertial-range of this imbalanced cascade has the following properties: (i) the
ratio of the r.m.s. Elsasser amplitudes is independent of scale, and is equal
to the ratio of the corresponding energy fluxes; (ii) in common with the
balanced strong cascade, the energy spectra of both Elsasser waves are of the
anisotropic Kolmogorov form, with their parallel correlation lengths equal to
each other on all scales, and proportional to the two-thirds power of the
transverse correlation length; (iii) the equality of cascade time and
waveperiod (critical balance) that characterizes the strong balanced cascade
does not apply to the Elsasser field with the larger amplitude. Instead, the
more general criterion that always applies to both Elsasser fields is that the
cascade time is equal to the correlation time of the straining imposed by
oppositely-directed waves. Our results are particularly relevant for turbulence
in the solar wind. Spacecraft measurements have established that, in the
inertial range of solar wind turbulence, waves travelling away from the sun
have higher amplitudes than those travelling towards it. Result (i) allows us
to infer the turbulent flux ratios from the amplitude ratios, thus providing
insight into the origin of the turbulence.


title: Neutrino signatures of supernova turbulence

abstract:
  Convection that develops behind the shock front during the first second of a
core-collapse supernova explosion is believed to play a crucial role in the
explosion mechanism. We demonstrate that the resulting turbulent density
fluctuations may be directly observable in the neutrino signal starting at t>~
3-4 s after the onset of the explosion. The effect comes from the modulation of
the MSW flavor transformations by the turbulent density fluctuations. We derive
a simple and general criterion for neutrino flavor depolarization in a
Kolmogorov-type turbulence and apply it to the turbulence seen in modern
numerical simulations. The turbulence casts a "shadow", by making other
features, such as the shock front, unobservable in the density range covered by
the turbulence.


title:
Spectropolarimetry of the 3.4 micron Feature in the Diffuse ISM toward
  the Galactic Center Quintuplet Cluster

abstract:
  Aliphatic hydrocarbons exhibit an absorption feature at 3.4 micron observed
toward sources that sample diffuse regions of the interstellar medium. The
absorbers responsible for this feature are assumed to reside in some component
of interstellar dust, but the physical nature of the particles (size, shape,
structure, etc.) is uncertain. Observations of interstellar polarization
provide discrimination. Since the grains that carry the silicate absorption
feature are known to be aligned, polarization across the 3.4 micron hydrocarbon
feature can be used to test the silicate core-organic refractory mantle grain
theory. Although the 3.4 micron feature has been observed to be devoid of
polarization for one line of sight toward the Galactic center, a corresponding
silicate polarization measurement for the same line of sight was not available.
Here, we present spectropolarimetric observations toward GCS 3-II and GCS 3-IV
toward the Galactic center, where the 9.7 micron silicate polarization has been
previously observed. We show that polarization is not detected across the 3.4
micron feature to a limit of 0.06 +/- 0.13% (GCS 3-II) and 0.15 +/- 0.31% (GCS
3-IV), well below the lowest available prediction of polarization on the basis
of the core-mantle model. We conclude that the hydrocarbons in the diffuse ISM
do not reside on the same grains as the silicates and likely form a separate
population of small grains.


title: Smooth Boundaries to Cosmological HII Regions from Galaxy Clustering

abstract:
  The HII regions around quasars and galaxies at redshifts beyond the epoch of
reionisation will provide prime targets for upcoming 21cm campaigns using a new
generation of low-frequency radio observatories. Here we show that the
boundaries of these HII regions will not be sharp. Rather, the clustering of
sources near massive galaxies results in a neutral fraction that rises
gradually towards large radii from an interior value near zero. A neutral
fraction corresponding to the global background value is typically reached at a
distance of 2-5 times the radius of the HII region around the central massive
galaxy.


title: Analysis methods for Atmospheric Cerenkov Telescopes

abstract:
  Three different analysis techniques for Atmospheric Imaging System are
presented. The classical Hillas parameters based technique is shown to be
robust and efficient, but more elaborate techniques can improve the sensitivity
of the analysis. A comparison of the different analysis techniques shows that
they use different information for gamma-hadron separation, and that it is
possible to combine their qualities.


title: Slow glitches in the pulsar B1822-09

abstract:
  The pulsar B1822-09 (J1825-0935) experienced a series of five unusual slow
glitches over the 1995-2004 interval. The results of further study of this
unusual glitch phenomenon are presented. It is also reported the detection a
new glitch of typical signature that occurred in the pulsar period in 2006
January.


title:
Neutrinos from galactic sources of cosmic rays with known gamma-ray
  spectra

abstract:
  We describe a simple procedure to estimate the high-energy neutrino flux from
the observed gamma-ray spectra of galactic cosmic ray sources that are
transparent to their gamma radiation. We evaluate in this way the neutrino flux
from the supernova remnant RX J1713.7-3946, whose very high-energy gamma-ray
spectrum (assumed to be of hadronic origin) is not a power law distribution
according to H.E.S.S. observations. The corresponding muon signal in neutrino
telescopes is found to be about 5 events per square kilometer per year in an
ideal detector.


title:
Possibilities of analysis of brightness distributions for components of
  eclipsing variables from data of space photometry

abstract:
  We carried out numerical experiments on the evaluation of the possibilities
of obtaining the information about brightness distributions for the components
of eclipsing variables from the data of high-precision photometry expected for
planned satellites COROT and Kepler. We examined a simple model of the
eclipsing binary with the spherical components on circular orbits and the
linear law of the limb darkening. The solutions of light curves have been
obtained as by fitting of the nonlinear model, into the number of parameters of
which included the limb darkening coefficients, so also by the solution of the
ill-posed inverse problem of restoration of brightness distributions across the
disks of stars without rigid model constraints on the form of these functions.
The obtained estimations show that if the observational accuracy amounts to
0.0001 then the limb darkening coefficients can be found with the relative
error approximately 0.01 . The brightness distributions across the disks of
components can be restored also nearly with the same accuracy.


title:
XMM-Newton and ESO observations of the two unidentified gamma-ray
  sources 3EG J0616-3310 and 3EG J1249-8330

abstract:
  The limited angular resolution of gamma-ray telescopes prevents a direct
identification of the majority of sources detected so far. This is particularly
true for the low latitude, probably galactic, ones only 10 % of which has been
identified. Most counterparts of the identified low-latitude gamma-ray sources
are Isolated Neutron Stars (INS), both radio-loud and radio-quiet
(Geminga-like) objects, which are characterised by an extremely high value of
the X-ray-to-optical flux ratio f_X/f_opt. Therefore, the systematic X-ray and
optical coverage of low-latitude unidentified gamma-ray sources aiming at high
f_X/f_opt sources seems one of the most promising ways to spot INS candidate
counterparts. Since low latitude sources are heavily affected by the
interstellar absorption at both X-ray and optical wavelengths, we have focussed
on two middle-latitude, probably galactic, GRO/EGRET sources: 3EG J0616-3310
and 3EG J1249-8330. These two sources, which could belong to a local galactic
population, have been selected owing to their relatively good positional
accuracy, spectral shape and lack of candidate extragalactic radio
counterparts. Here we report on X-ray observations of the two gamma-ray error
boxes performed with XMM-Newton and on their optical follow-up carried on with
the Wide Field Imager at the ESO/MPG 2.2m telescope. Less than half of the ~300
sources detected by the X-ray coverage have no optical counterparts. Among
those, we have selected few interesting sources with f_X/f_opt > 100, which we
consider promising INS candidates.


title:
Crushing of interstellar gas clouds in supernova remnants II. X-ray
  emission

abstract:
  AIMS. We study and discuss the time-dependent X-ray emission predicted by
hydrodynamic modeling of the interaction of a SNR shock wave with an
interstellar gas cloud. The scope includes: 1) to study the correspondence
between modeled and X-ray emitting structures, 2) to explore two different
physical regimes in which either thermal conduction or radiative cooling plays
a dominant role, and 3) to investigate the effects of the physical processes at
work on the emission of the shocked cloud in the two different regimes.
  METHODS. We use a detailed hydrodynamic model, including thermal conduction
and radiation, and explore two cases characterized by different Mach numbers of
the primary shock: M = 30 in which the cloud dynamics is dominated by radiative
cooling and M = 50 dominated by thermal conduction. From the simulations, we
synthesize the expected X-ray emission, using available spectral codes.
  RESULTS. The morphology of the X-ray emitting structures is significantly
different from that of the flow structures originating from the shock-cloud
interaction. The hydrodynamic instabilities are never clearly visible in the
X-ray band. Shocked clouds are preferentially visible during the early phases
of their evolution. Thermal conduction and radiative cooling lead to two
different phases of the shocked cloud: a cold cooling dominated core emitting
at low energies and a hot thermally conducting corona emitting in the X-ray
band. The thermal conduction makes the X-ray image of the cloud smaller, more
diffuse, and shorter-lived than that observed when thermal conduction is
neglected.


title: Complex emission line region of Mrk 817

abstract:
  In this work we study the physical and kinematical properties of the emission
line region of Seyfert 1.5 galaxy Mrk 817 using three sets of observations,
among which are high-resolution spectra obtained with the Isaac Newton
Telescope on Canary Islands. We find that in Mrk 817 the Narrow (NEL) and Broad
Emission Lines (BEL) are very complex, indicating that structure of both the
Narrow (NLR) and Broad Line Region (BLR) is complex and consists of at least
two sub-regions with different kinematical properties. We find that the BEL can
be fitted with the two-component model, where the core of the line is coming
from a spherical region with isotropic velocity distribution, and wings might
be affected by a low inclined accretion disc (or disc-like emitting region).
Also, we discuss the physical properties of the BLR. Moreover, we find that an
outflow is present in the NLR, that may be driven by an approaching jet.


title: Searching dark-matter halos in the GaBoDS survey

abstract:
  We apply the linear filter for the weak-lensing signal of dark-matter halos
developed in Maturi et al. (2005) to the cosmic-shear data extracted from the
Garching-Bonn-Deep-Survey (GaBoDS). We wish to search for dark-matter halos
through weak-lensing signatures which are significantly above the random and
systematic noise level caused by intervening large-scale structures. We employ
a linear matched filter which maximises the signal-to-noise ratio by minimising
the number of spurious detections caused by the superposition of large-scale
structures (LSS). This is achieved by suppressing those spatial frequencies
dominated by the LSS contamination. We confirm the improved stability and
reliability of the detections achieved with our new filter compared to the
commonly-used aperture mass (Schneider, 1996; Schneider et al., 1998) and to
the aperture mass based on the shear profile expected for NFW haloes (see e.g.
Schirmer et al., 2004; Hennawi & Spergel, 2005). Schirmer et al.~(2006)
achieved results comparable to our filter, but probably only because of the low
average redshift of the background sources in GaBoDS, which keeps the LSS
contamination low. For deeper data, the difference will be more important, as
shown by Maturi et al. (2005). We detect fourteen halos on about eighteen
square degrees selected from the survey. Five are known clusters, two are
associated with over-densities of galaxies visible in the GaBoDS image, and
seven have no known optical or X-ray counterparts.


title: Cosmology with CMB anisotropy

abstract:
  Measurements of CMB anisotropy and, more recently, polarization have played a
very important role allowing precise determination of various parameters of the
`standard' cosmological model. The expectation of the paradigm of inflation and
the generic prediction of the simplest realization of inflationary scenario in
the early universe have also been established -- `acausally' correlated initial
perturbations in a flat, statistically isotropic universe, adiabatic nature of
primordial density perturbations. Direct evidence for gravitational instability
mechanism for structure formation from primordial perturbations has been
established. In the next decade, future experiments promise to strengthen these
deductions and uncover the remaining crucial signature of inflation -- the
primordial gravitational wave background.


title: Electromagnetic Pulsar Spindown

abstract:
  This paper has been withdrawn by the author. It will be posted on astro-ph
once the proceedings of the 363rd Heraeus Seminar on Neutron Stars and Pulsars
are ready.


title:
Noncommutative Black-Body Radiation: Implications On Cosmic Microwave
  Background

abstract:
  Including loop corrections, black-body radiation in noncommutative space is
anisotropic. A direct implication of possible space noncommutativity on the
Cosmic Microwave Background map is argued.


title:
Simultaneous radio-interferometric and high-energy TeV observations of
  the gamma-ray blazar Mkn 421

abstract:
  The TeV-emitting BL Lac object Mkn 421 was observed with very long baseline
interferometry (VLBI) at three closely-spaced epochs one-month apart in
March-April 1998. The source was also monitored at very-high gamma-ray energies
(TeV measurements) during the same period in an attempt to search for
correlations between TeV variability and the evolution of the radio morphology
on parsec scales. While the VLBI maps show no temporal changes in the Mkn 421
VLBI jet, there is strong evidence of complex variability in both the total and
polarized fluxes of the VLBI core of Mkn 421 and in its spectrum over the
two-month span of our data. The high-energy measurements indicate that the
overall TeV activity of the source was rising during this period, with a
gamma-ray flare detected just three days prior to our second VLBI observing
run. Although no firm correlation can be established, our data suggest that the
two phenomena (TeV activity and VLBI core variability) are connected, with the
VLBI core at 22 GHz being the self-absorbed radio counterpart of synchrotron
self-Compton (SSC) emission at high energies. Based on the size of the VLBI
core, we could derive an upper limit of 0.1 pc (3 x 10**17 cm) for the
projected size of the SSC zone. This determination is the first model-free
estimate of the size of the gamma-ray emitting region in a blazar.


title: PSF reconstruction for NAOS-CONICA

abstract:
  Adaptive optics (AO) allows one to derive the point spread function (PSF)
simultaneously to the science image, which is a major advantage in
post-processing tasks such as astrometry/photometry or deconvolution. Based on
the algorithm of \citet{veran97}, PSF reconstruction has been developed for
four different AO systems so far: PUEO, ALFA, Lick-AO and Altair. A similar
effort is undertaken for NAOS/VLT in a collaboration between the group PHASE
(Onera and Observatoire de Paris/LESIA) and ESO. In this paper, we first
introduce two new algorithms that prevent the use of the so-called "$U\_{ij}$
functions" to: (1) avoid the storage of a large amount of data (for both new
algorithms), (2) shorten the PSF reconstruction computation time (for one of
the two) and (3) provide an estimation of the PSF variability (for the other
one). We then identify and explain issues in the exploitation of real-time
Shack-Hartmann (SH) data for PSF reconstruction, emphasising the large impact
of thresholding in the accuracy of the phase residual estimation. Finally, we
present the data provided by the NAOS real-time computer (RTC) to reconstruct
PSF ({\em (1)} the data presently available, {\em (2)} two NAOS software
modifications that would provide new data to increase the accuracy of the PSF
reconstruction and {\em (3)} the tests of these modifications) and the PSF
reconstruction algorithms we are developing for NAOS on that basis.


title: 30 Glitches in slow pulsars

abstract:
  We have analyzed 5.5 years of timing observations of 7 'slowly' rotating
radio pulsars, made with the Westerbork Synthesis Radio Telescope. We present
improved timing solutions and 30, mostly small, new glitches. Particularly
interesting are our results on PSR J1814-1744, which is one of the pulsars with
similar rotation parameters and magnetic field strength to the Anomalous X-ray
Pulsars (AXPs). Although the high-B radio pulsars do not show X-ray emission,
and no radio emission is detected for AXPs, the roughly similar glitch
parameters provide us with another tool to compare these classes of neutron
stars. Furthermore, we were able to detect glitches one to two orders of
magnitude smaller than before, for example in our well-sampled observations of
PSR B0355+54. We double the total number of known glitches in PSR B1737-30, and
improve statistics on glitch sizes for this pulsar individually and pulsars in
general. We detect no significant variations in dispersion measure for PSRs
B1951+32 and B2224+65, two pulsars located in high-density surroundings. We
discuss the effect of small glitches on timing noise, and show it is possible
to resolve timing-noise looking structures in the residuals of PSR B1951+32 by
using a set of small glitches.


title: An asteroseismic study of the beta Cephei star beta Canis Majoris

abstract:
  We present the results of a detailed analysis of 452 ground-based
high-resolution high S/N spectroscopic measurements spread over 4.5 years for
beta Canis Majoris with the aim to determine the pulsational characteristics of
this star, and to use them to derive seismic constraints on the stellar
parameters. We determine pulsation frequencies in the SiIII 4553 Angstrom line
with Fourier methods. We identify the m-value of the modes by taking into
account the photometric identifications of the degrees l. To this end we use
the moment method together with the amplitude and phase variations across the
line profile. The frequencies of the identified modes are used for a seismic
interpretation of the structure of the star. We confirm the presence of the
three pulsation frequencies already detected in previous photometric datasets:
f_1 = 3.9793 c/d (46.057 microHz), f_2 = 3.9995 c/d (46.291 microHz) and f_3 =
4.1832 c/d (48.417 microHz). For the two modes with the highest amplitudes we
unambiguously identify (l_1,m_1) = (2,2) and (l_2,m_2) = (0,0). We cannot
conclude anything for the third mode identification, except that m_3 > 0. We
also deduce an equatorial rotational velocity of 31 +/- 5 Km/s for the star. We
show that the mode f_1 must be close to an avoided crossing. Constraints on the
mass (13.5 +/- 0.5 Msun), age (12.4 +/- 0.7 Myr) and core overshoot (0.20 +/-
0.05 H_P) of beta CMa are obtained from seismic modelling using f_1 and f_2.


title: Constraints on Quintessence From Using Cosmological Data

abstract:
  Recent data, including the three--year WMAP data, the full 2dF galaxy power
spectrum and the first--year data of the Supernova Legacy Survey, are used to
constrain model parameters in quintessence cosmologies. In particular, we
discuss the inverse power--law (RP) and SUGRA potentials and compare parameter
constraints with those for LCDM. Both potentials fit current observations with
a goodness of fit comparable or better than LCDM. The constraints on the energy
scale Lambda_DE appearing in both potential expressions are however different.
For RP, only energy scales around the cosmological constant limit are allowed,
making the allowed models quite similar to LCDM. For SUGRA, Lambda_DE values
approximately up to Electroweak energy scale are still allowed, while other
parameter intervals are slightly but significantly displaced. In particular a
value of the primeval spectral index n_s = 1 is still allowed at the 95% c.l.,
and this can have an impact on constraints on possible inflationary potentials.


title:
Diffuse Light in Hickson Compact Groups: The Dynamically Young System
  HCG 44

abstract:
  Compact groups are associations of a few galaxies in which the environment
plays an important role in galaxy evolution. The low group velocity dispersion
favors tidal interactions and mergers, which may bring stars from galaxies to
the diffuse intragroup light. Numerical simulations of galaxy clusters in
hierarchical cosmologies show that the amount of the diffuse light increases
with the dynamical evolution of the cluster. We search for diffuse light in the
galaxy group HCG 44 in order to determine its luminosity and luminosity
fraction. Combining with literature data, we aim to constrain the dynamical
status of Hickson compact groups. We use Intra Group planetary nebulae (IGPNe)
as tracers of diffuse light. These are detected by the so-called on band-off
band technique. We found 12 emission line objects in HCG 44, none of them
associated with the galaxies of the group. 6/12 emission line objects are
consistent with being IGPNe in HCG 44, but are also consistent with being
Ly$\alpha$ background galaxies. Thus we derive an upper limit to the diffuse
light fraction in HCG 44 of 4.7%. We find a correlation between the fraction of
elliptical galaxies and the amount of diffuse light in Hickson compact groups.
Those with large fraction of diffuse light are those with large fractions in
number and luminosity of E/S0 galaxies. We propose an evolutionary sequence for
Hickson compact groups in which the amount of diffuse light increases with the
dynamical evolution of the group.


title:
Abundance analysis of prime B-type targets for asteroseismology I.
  Nitrogen excess in slowly-rotating beta Cephei stars

abstract:
  We present the results of a detailed NLTE abundance study of nine beta Cephei
stars, all of them being prime targets for theoretical modelling: gamma Peg,
delta Cet, nu Eri, beta CMa, xi1 CMa, V836 Cen, V2052 Oph, beta Cep and DD (12)
Lac. The following chemical elements are considered: He, C, N, O, Mg, Al, Si, S
and Fe. Our abundance analysis is based on a large number of time-resolved,
high-resolution optical spectra covering in most cases the entire oscillation
cycle of the stars. Nitrogen is found to be enhanced by up to 0.6 dex in four
stars, three of which have severe constraints on their equatorial rotational
velocity, \Omega R, from seismic or line-profile variation studies: beta Cep
(\Omega R~26 km/s), V2052 Oph (\Omega R~56 km/s), delta Cet (\Omega R < 28
km/s) and xi1 CMa (\Omega R sin i < 10 km/s). The existence of core-processed
material at the surface of such largely unevolved, slowly-rotating objects is
not predicted by current evolutionary models including rotation. We draw
attention to the fact that three stars in this subsample have a detected
magnetic field and briefly discuss recent theoretical work pointing to the
occurrence of diffusion effects in beta Cephei stars possibly capable of
altering the nitrogen surface abundance. On the other hand, the abundances of
all the other chemical elements considered are, within the errors,
indistinguishable from the values found for OB dwarfs in the solar
neighbourhood. Despite the mild nitrogen excess observed in some objects, we
thus find no evidence for a significantly higher photospheric metal content in
the studied beta Cephei stars compared to non-pulsating B-type stars of similar
characteristics.


title: Extended Emission by Dust in the Dwarf Galaxy UGC 10445

abstract:
  We present Spitzer Space Telescope images of the isolated dwarf galaxy UGC
10445. The galaxy is detected at all photometric bands (3.6-160um) as well as
in the Multiband Imaging Photometer for Spitzer (MIPS) spectral energy
distribution mode (55-95um). We derive a star formation rate of 0.25 M_sun/yr
based on H-alpha and infrared flux densities. There is over 10^6 solar masses
of cold dust (T~18K) in the galaxy, represented by 160um emission, that extends
to a larger radius than the ultraviolet (UV), optical and near-infrared light.
Such extended emission has been seen previously only in dwarf galaxies in
cluster environments. We suggest the source of heating for this dust is UV
light originating in star forming complexes. To produce the large quantity of
dust requires a higher rate of star formation in the past than is observed
currently.


title:
First science with SALT: peering at the accreting polar caps of the
  eclipsing polar SDSS J015543.40+002807.2

abstract:
  We describe briefly the properties of the recently completed Southern African
Large Telescope (SALT), along with its first light imager SALTICAM. Using this
instrument, we present 4.3 hr of high speed unfiltered photometric observations
of the eclipsing polar SDSSJ015543.40+002807.2 with time resolution as short as
112 ms, the highest quality observations of this kind of any polar to date. The
system was observed during its high luminosity state. Two accreting poles are
clearly seen in the eclipse light curve. The binary system parameters have been
constrained: the white dwarf mass is at the low end of the range expected for
cataclysmic variables. Correlations between the positions of the accretion
regions on or near the surface of the white dwarf and the binary system
parameters were established. The sizes of the accretion regions and their
relative movement from eclipse to eclipse were estimated: they are typically
4-7 deg depending on the mass of the white dwarf. The potential of these
observations will only fully be realised when low state data of the same kind
are obtained and the contact phases of the eclipse of the white dwarf are
measured.


title: Atomic Carbon in APM 08279+5255 at z=3.91

abstract:
  We present a detection of [CI] line emission in the lensed quasar APM
08279+5255 at z=3.91 using the IRAM Plateau de Bure interferometer. The [CI]
line velocity and width are similar to the values of previously detected high-J
CO and HCN lines in this source, suggesting that the emission from all of these
species arises from the same region. The apparent luminosity of the [CI] line
is L'(CI) = (3.1 +/- 0.4)x10^10 K km/s pc^2, which implies a neutral carbon
mass, M(CI) = (4.4+/-0.6)/m x10^7 M_sun, where m is the lensing magnification
factor. The [CI] line luminosity is consistent with the large molecular gas
mass inferred from the nuclear CO line luminosity ~10^11 /m M_sun. We also
present an upper limit on the H2O line luminosity in APM 08279+5255 of, L'(H2O)
< 1.8x10^10 K km/s pc^2 (3-sigma).


title:
Planetesimal formation via fragmentation in self-gravitating
  protoplanetary discs

abstract:
  An unsolved issue in the standard core accretion model for gaseous planet
formation is how kilometre-sized planetesimals form from, initially,
micron-sized dust grains. Solid growth beyond metre sizes can be difficult both
because the sticking efficiency becomes very small, and because these particles
should rapidly migrate into the central star. We consider here how metre-sized
particles evolve in self-gravitating accretion discs using simulations in which
the gravitational influence of the solid particles is also included.
Metre-sized particles become strongly concentrated in the spiral structures
present in the disc and, if the solid to gas density ratio is sufficiently
high, can fragment due to their own self-gravity to form planetesimals
directly. This result suggests that planetesimal formation may occur very early
in the star formation process while discs are still massive enough to be
self-gravitating. The dependence of this process on the surface density of the
solids is also consistent with the observation that extrasolar planets are
preferentially found around high metallicity stars.


title:
Structural Parameters for Globular Clusters in NGC 5128. II: HST/ACS
  Imaging and New Clusters

abstract:
  We report the first results from an imaging program with the ACS camera on
HST designed to measure the structural characteristics of a wide range of
globular clusters in NGC 5128, the nearest giant elliptical galaxy. From 12
ACS/WFC fields, we have measured a total of 62 previously known globular
clusters and have discovered 69 new high-probability cluster candidates not
found in any previous work. We present magnitudes and color indices for all of
these, along with rough measurements of their effective diameters and
ellipticities. The luminosity distribution of this nearly-uncontaminated sample
of clusters matches well with the normal GCLF for giant elliptical galaxies,
and the cluster scale size and ellipticity distributions are similar to those
in the Milky Way system. The indication from this survey is that many hundreds
of individual clusters remain to be found with carefully designed search
techniques in the future. A very rough estimate of the total cluster population
from our data suggests N_GC = 1500 in NGC 5128, over all magnitudes and within
a projected radius R = 25' from the galaxy center.


title: AEGIS: The color-magnitude relation for X-ray selected AGN

abstract:
  We discuss the relationship between rest-frame color and optical luminosity
for X-ray sources in the range 0.6<z<1.4 selected from the Chandra survey of
the Extended Groth Strip (EGS). These objects are almost exclusively active
galactic nuclei (AGN). While there are a few luminous QSOs, most are relatively
weak or obscured AGN whose optical colors should be dominated by host galaxy
light. The vast majority of AGN hosts at z~1 are luminous and red, with very
few objects fainter than M_{B}=-20.5 or bluer than U-B=0.6. This places the AGN
in a distinct region of color-magnitude space, on the ``red sequence'' or at
the top of the ``blue cloud'', with many in between these two modes in galaxy
color. A key stage in the evolution of massive galaxies is when star formation
is quenched, resulting in a migration from the blue cloud to the red sequence.
Our results are consistent with scenarios in which AGN either cause or maintain
this quenching. The large numbers of red sequence AGN imply that strong,
ongoing star formation is not a necessary ingredient for AGN activity, as black
hole accretion appears often to persist after star formation has been
terminated.