title:
Star formation rates and chemical abundances of emission line galaxies
  in intermediate-redshift clusters

abstract:
  We examine the evolutionary status of luminous, star-forming galaxies in
intermediate-redshift clusters by considering their star formation rates and
the chemical and ionsiation properties of their interstellar emitting gas. Our
sample consists of 17 massive, star-forming, mostly disk galaxies with
M_{B}<-20, in clusters with redshifts in the range 0.31< z <0.59, with a median
of <z>=0.42. We compare these galaxies with the identically selected and
analysed intermediate-redshift field sample of Mouhcine et al. (2006), and with
local galaxies from the Nearby Field Galaxy Survey of Jansen et al. (2000).
  From our optical spectra we measure the equivalent widths of OII, Hbeta and
OIII emission lines to determine diagnostic line ratios, oxygen abundances, and
extinction-corrected star formation rates. The star-forming galaxies in
intermediate-redshift clusters display emission line equivalent widths which
are, on average, significantly smaller than measured for field galaxies at
comparable redshifts. However, a contrasting fraction of our cluster galaxies
have equivalent widths similar to the highest observed in the field. This
tentatively suggests a bimodality in the star-formation rates per unit
luminosity for galaxies in distant clusters. We find no evidence for further
bimodalities, or differences between our cluster and field samples, when
examining additional diagnostics and the oxygen abundances of our galaxies.
This maybe because no such differences exist, perhaps because the cluster
galaxies which still display signs of star-formation have recently arrived from
the field. In order to examine this topic with more certainty, and to further
investigate the way in which any disparity varies as a function of cluster
properties, larger spectroscopic samples are needed.


title:
A new model for the Warm Absorber in NGC 3783: a single medium in total
  pressure equilibrium

abstract:
  (Abridged) Many active galactic nuclei exhibit X-ray features typical of the
highly ionized gas called "Warm Absorber" (WA). Such a material appears to be
stratified, displaying zones of different density, temperature, and ionization.
In this paper, we investigate the possibility of modelling the WA gas in NGC
3783 as a single medium in total pressure equilibrium, in contrast to the
current descriptions that are based on the presence of multiple regions, each
in constant density. The assumption of total pressure equilibrium yields a more
physical description of the WA, resulting in the natural stratification of the
ionized gas, and providing an explanation for the presence of lines from
different ionization states, as observed in WA spectra. We have used the
photoionization code TITAN to compute a grid of constant total pressure models
with the purpose of fitting the WA in NGC 3783. We have compared our models to
the 900 ks Chandra spectrum of NGC 3783 and to previous studies where the WA
was described by multiple zones of constant density. Our results show that the
WA features in NGC 3783 can be well reproduced by a clumpy, ionized gas with
cosmic abondances, ionization parameter = 2500 erg cm s^-1, column density = 4
10^22 cm^-2, and constant total pressure. We have shown that the WA in NGC3783
can be modelled by a single medium in total pressure equilibrium; this is
probably the case for other WAs currently described by multi-zone, constant
density models.


title: On near Chandrasekhar mass central stars of planetary nebulae

abstract:
  A recent spectroscopic analysis of central stars of planetary nebulae (CSPNe)
claims that the sample includes five CSPNe with masses very close to the
Chandrasekhar limit of white dwarfs. This claim should be verified or discarded
from the available kinematical and chemical abundance information. Kinematical
parameters are extracted from Galactic orbits and compared with parameters
expected for populations of different ages. The chemistry of the nebulae is
compared with average values for different types. The reported high masses are
not supported by our investigation. The claimed high central star masses are in
contradiction with all other evidence. A more consistent picture emerges if
CSPN masses close to the peak of the white dwarf mass distribution are assumed.


title:
The Hubble Constant from Type Ia Supernova Calibrated with the Linear
  and Non-Linear Cepheid Period-Luminosity Relation

abstract:
  It is well-known that the peak brightness of the Type Ia supernovae
calibrated with Cepheid distances can be used to determine the Hubble constant.
The Cepheid distances to host galaxies of the calibrating supernovae are
usually obtained using the period-luminosity (PL) relation derived from Large
Magellanic Cloud (LMC) Cepheids. However recent empirical studies provide
evidence that the LMC PL relation is not linear. In this Letter we determine
the Hubble constant using both the linear and non-linear LMC Cepheid PL
relations as calibrating relations to four galaxies that hosted Type Ia
supernovae. Our results suggest that the obtained values of the Hubble constant
are similar. However a typical error of $\sim0.03$mag. has to be added (in
quadrature) to the systematic error for the Hubble constant when the linear LMC
PL relation is used, assuming that the LMC PL relation is indeed non-linear.
This is important in minimizing the total error of the Hubble constant in the
era of precision cosmology. The Hubble constants calibrated from the linear and
non-linear LMC PL relation are H_0 = 74.92+-2.28(random)+-5.06(systematic)
km/s/Mpc and H_0 = 74.37+-2.27(random)+-4.92(systematic) km/s/Mpc,
respectively. Hubble constants calculated using the Galactic PL relations are
also briefly discussed and presented in the last section of this Letter.


title:
Effects of color superconductivity on the nucleation of quark matter in
  neutron stars

abstract:
  We study the nucleation of quark matter drops at the center of cold
deleptonized neutron stars. This is relevant in the determination of the
critical mass $M_{cr}$ of hadronic stars above which it is possible a
transition to a quark star (strange or hybrid). We investigate the dependence
of $M_{cr}$ upon the parameters of the quark model (the Bag constant $B$, the
pairing gap $\Delta$, and the surface tension $\sigma$ of the quark-hadron
interphase) and for different parametrization of the hadronic equations of
state. The dependence of $M_{cr}$ on $B$, $\Delta$ and $\sigma$ is mild if the
parameters of the quark model correspond to hybrid stars, and strong if they
correspond to strange stars. For a large part of the parameter space
corresponding to hybrid stars, the critical mass is very close (but smaller
than) the maximum mass of hadronic stars, and therefore compatible with a
"mixed" population of compact stars (pure hadronic up to the critical mass and
hybrid above the critical mass). For very large $B$ the critical mass is never
smaller than the maximum mass of hadronic stars, implying that quark stars
cannot form through the here studied mechanism. The energy released in the
conversion is $3 \times 10^{52}$ erg - $4 \times 10^{53}$ erg, i.e. sufficient
to power a gamma ray burst.


title:
Faraday rotation variations along radio jets: the magnetic field in
  galaxy and group halos

abstract:
  Our modelling of FR I radio jets as decelerating, relativistic flows allows
us to derive their orientations accurately. We present images of Faraday
rotation for two of these these objects (3C 31 and NGC 315) and show that the
fluctuations of rotation measure (RM) are larger in the fainter (receding)
jets, as expected if the rotation occurs in the hot galaxy/group halos. The gas
density is much lower in NGC 315 and the RM fluctuations are only just
detectable.


title: Distribution of extinction and star formation in NGC1569

abstract:
  We investigate the distribution of the intrinsic extinction in NGC1569 using
an extinction map derived from the H_alpha/H_beta emission line ratio. We
compare the extinction distribution to that of the dust emission traced by
SPITZER IRAC(8microns) and MIPS (24microns) maps. The intrinsic extinction
shows spatial variations, from zones with negligible extinction to zones with
values up to A(V)=0.8mag. We find an extinction shell and establish a relation
between this shell and the interstellar expanding structure produced by the
stellar winds comig from the Super Star Cluster (SSCs) A and B in the center of
the galaxy. We suggest that the extinction shell has been produced by the
accumulation of dust at the border of the shell. Although we find a good
spatial correlation between the Balmer extinction and infrared emission, there
is a spatial displacement between the 8microns and 24microns maxima and the
maximum in Balmer extinction which needs further investigation.


title:
The Hubble Constant: A Summary of the HST Program for the Luminosity
  Calibration of Type Ia Supernovae by Means of Cepheids

abstract:
  This is the fifth and final summary paper of our 15 year program using the
Hubble Space Telescope (HST) to determine the Hubble constant using Type Ia
supernovae, calibrated with Cepheid variables in nearby galaxies that hosted
them. Several developments not contemplated at the start of the program in 1990
have made it necessary to put the summary on H_0 on a broader basis than
originally thought, making four preparatory papers necessary. The new Cepheid
distances of the subset of 10 galaxies, which were hosts of normal SNeIa, give
weighted mean luminosities in B, V, and I at maximum light of -19.49, -19.46,
and -19.22, respectively. These calibrate the adopted SNeIa Hubble diagram from
Paper III to give a global value of H_0 = 62.3 +/- 1.3 (random) +/- 5.0
(systematic). Local values of H_0 between 4.4 and 30 Mpc from Cepheids, SNeIa,
21cm-line widths, and the tip of the red-giant branch (TRGB) all agree within
5% of our global value. This agreement of H_0 on all scales from 4 - 200 Mpc
finds its most obvious explanation in the smoothing effect of vacuum energy on
the otherwise lumpy gravitational field due to the non-uniform distribution of
the local galaxies. The physical methods of time delay of gravitational lenses
and the Sunyaev-Zeldovich effect are consistent (but with large errors) with
our global value. The present result is also not in contradiction with existing
analyses of CMB data, because they either lead to wide error margins of H_0 or
depend on the choice of unwarrented priors that couple the value of H_0 with a
number of otherwise free parameters in the CMB acoustic waves. Our value of H_0
is 14% smaller than the value of H_0 found by Freedman et al. (2001) because
our independent Cepheid distances to the six SNeIa-calibrating galaxies used in
that analysis average 0.35mag larger than those used earlier.


title:
Cosmic Evolution of Black Holes and Spheroids. I: The M_BH-sigma
  Relation at z=0.36

abstract:
  We test the evolution of the correlation between black hole mass and bulge
velocity dispersion (M$_{\rm BH}-\sigma$), using a carefully selected sample of
14 Seyfert 1 galaxies at $z=0.36\pm0.01$. We measure velocity dispersion from
stellar absorption lines around Mgb (5175\AA) and Fe (5270\AA) using high S/N
Keck spectra, and estimate black hole mass from the H$\beta$ line width and the
optical luminosity at 5100\AA, based on the empirically calibrated
photo-ionization method. We find a significant offset from the local relation,
in the sense that velocity dispersions were smaller for given black hole masses
at $z=0.36$ than locally. We investigate various sources of systematic
uncertainties and find that those cannot account for the observed offset. The
measured offset is $\Delta \log M_{\rm BH}=0.62 \pm 0.10 \pm 0.25$, i.e.
$\Delta \log \sigma=0.15 \pm 0.03 \pm 0.06$, where the error bars include a
random component and an upper limit to the systematics. At face value, this
result implies a substantial growth of bulges in the last 4 Gyr, assuming that
the local M$_{\rm BH}-\sigma$ relation is the universal evolutionary end-point.
Along with two samples of active galaxies with consistently determined black
hole mass and stellar velocity dispersion taken from the literature, we
quantify the observed evolution with the best fit linear relation, $\Delta \log
M_{\rm BH} = (1.66\pm0.43)z + (0.04\pm0.09)$ with respect to the local
relationship of Tremaine et al. (2002), and $\Delta \log M_{\rm BH} =
(1.55\pm0.46)z + (0.01\pm0.12)$ with respect to that of Ferrarese (2002). This
result is consistent with the growth of black holes predating the final growth
of bulges at these mass scales ($<\sigma>$=170 km s$^{-1}$).


title:
A remark on ``On the Formation and Progenitor of PSR J0737-3039: New
  Constraints on the Supernova Explosion Forming Pulsar B" by Willems et al.,
  astro-ph/0602024

abstract:
  Shortly after the discovery of the binary system PSR J0737-3039 we predicted
that it has a small proper motion and suggested that this implies that the
progenitor mass of the younger pulsar (B) must be around 1.45M_sun. This is in
contradiction to standard evolutionary scenarios that suggest a He-star
progenitor with M >2.1-2.3M_sun and in sharp contrast to a velocity of ~100
km/s predicted by these models. It requires a new previously unseen type of
gravitational collapse. Our (generally ignored) prediction of a low peculiar
motion was confirmed later by pulsar timing observations that found v_\bot < 30
km/s. Recently Willems et al. put forward an elaborate simulation suggesting
that in spite of these observations, the most likely natal kick is large
(50-170 km/s) and the corresponding most likely progenitor mass is large as
well. We refute this claim and show that Willems et al. implicitly assume the
result that they obtain.


title: Potential Condensed Fuel for the Milky Way

abstract:
  Potential condensed clouds of gas in the Galactic halo are examined in the
context of the recent models of cooling, fragmenting clouds building up the
baryonic mass of the Galaxy. 582 high-velocity clouds (HVCs) are defined as the
potential infalling, condensed clouds and the sample's spatial and velocity
distribution are presented. With the majority of the hydrogen in the clouds
ionized (~85%), the clouds at a distribution of distances within 150 kpc, and
their individual total masses below 10^7 Msun, the total mass in potentially
condensed clouds is 1.1 - 1.4 x 10^9 Msun. If the tighter distance constraint
of < 60 kpc is adopted this mass range drops to 4.5 - 6.1 x 10^8 Msun. The
implications on the condensing cloud models, as well as feedback and additional
accretion methods, are discussed.


title:
Galactic Planetary Nebulae with Wolf-Rayet Nuclei III. Kinematical
  Analysis of a Large Sample of Nebulae

abstract:
  Expansion velocities (Vexp) of different ions and line widths at the base of
the lines are measured and analyzed for 24 PNe with [WC]-type nuclei (WRPNe), 9
PNe ionized by WELS (WLPNe) and 14 ordinary PNe. A comparative study of the
kinematical behavior of the sample clearly demonstrates that WRPNe have in
average 40-45% larger Vexp, and possibly more turbulence than WLPNe and
ordinary PNe. WLPNe have velocity fields very much alike the ones of ordinary
PNe, rather than the ones of WRPNe. All the samples (WRPNe, WLPNe and ordinary
PNe) show expansion velocities increasing with age indicators, for example
<Vexp> is larger for low-density nebulae and also it is larger for nebulae
around high-temperature stars. This age effect is much stronger for evolved
WRPNe, suggesting that the [WC] winds have been accelerating the nebulae for a
long time, while for non-WRPNe the acceleration seems to stop at some point
when the star reaches a temperature of about 90,000-100,000 K. Non-WR nebulae
reach a maximum Vexp < 30 km/s while evolved WRPNe reach maximum Vexp of about
40 km/s. For all kind of objects (WRPNe and non-WRPNe) it is found that in
average Vexp(N+) is slightly larger than Vexp(O++), indicating that the nebulae
present acceleration of the external shells.


title:
Observational Evidence for Gentle Chromospheric Evaporation During the
  Impulsive Phase of a Solar Flare

abstract:
  Observational evidence for gentle chromospheric evaporation during the
impulsive phase of a C9.1 solar flare is presented using data from the Reuven
Ramaty High-Energy Solar Spectroscopic Imager and the Coronal Diagnostic
Spectrometer on board the Solar and Heliospheric Observatory. Until now,
evidence for gentle evaporation has often been reported during the decay phase
of solar flares, where thermal conduction is thought to be the driving
mechanism. Here we show that the chromospheric response to a low flux of
nonthermal electrons (>=5x10^9 ergs cm^-2 s^-1) results in plasma upflows of
13+/-16, 16+/-18, and 110+/-58 km s^-1 in the cool He I and O V emission lines
and the 8 MK Fe XIX line. These findings, in conjunction with other recently
reported work, now confirm that the dynamic response of the solar atmosphere is
sensitively dependent on the flux of incident electrons.


title: The Orbital Period of the Ultraluminous X-ray Source in M82

abstract:
  The ultraluminous x-ray source (ULX) in the galaxy M82 has been identified as
a possible intermediate-mass black hole. We have found that the x-ray flux from
M82 is modulated with a peak-to-peak amplitude corresponding to an isotropic
luminosity of 2.4x10^40 erg/s in M82 and a period of 62.0 +/- 2.5 days, which
we interpret as the orbital period of the ULX binary. This orbital period
implies that the mass-donor star must be a giant or supergiant. Large
mass-transfer rates, sufficient to fuel the ULX, are expected for a giant-phase
mass donor in an x-ray binary. The giant phase has a short lifetime, indicating
that we see the ULX in M82 in a brief and unusual period of its evolution.


title: On the Determination of N and O Abundances in Low Metallicity Systems

abstract:
  We show that in order to minimize the uncertainties in the N and O abundances
of low mass, low metallicity (O/H less than or equal to solar/5) emission-line
galaxies, it is necessary to employ separate parameterizations for inferring
Te[N II] and Te[O II] from Te[O III]. In addition, we show that for the above
systems, the ionization correction factor (ICF) for obtaining N/O from N+/O+,
where the latter is derived from optical emission-line flux ratios, is < ICF >
= 1.08 +/- 0.09. These findings are based on state-of-the-art single-star H II
region simulations, employing our own modeled stellar spectra as input. Our
models offer the advantage of having matching stellar and nebular abundances.
In addition, they have O/H as low as solar/50 (lower than any past work), as
well as log(N/O) and log(C/O) fixed at characteristic values of -1.46 and -0.7,
respectively. The above results were used to re-derive N and O abundances for a
sample of 68 systems with 12 + log(O/H) less than or equal to 8.1, whose
de-reddened emission-line strengths were collected from the literature. The
analysis of the log(N/O) versus 12 + log(O/H) diagram of the above systems
shows the following: (1) the largest group of objects forms the well-known N/O
plateau with a value for the mean (and its statistical error) of -1.43
(+.0084/-.0085); (2) the objects are distributed within a range in log(N/O) of
-1.54 to -1.27 in Gaussian fashion around the mean with a standard deviation of
sigma = +.071 / -.084; and (3) a chi-square analysis suggests that only a small
amount of the observed scatter in log(N/O) is intrinsic.


title:
A Combined EIS-NVSS Survey Of Radio Sources II: Infrared imaging and the
  K-z relation

abstract:
  The Combined EIS-NVSS Survey Of Radio Sources (CENSORS) is a 1.4 GHz radio
survey selected from the NRAO VLA Sky Survey (NVSS) and complete to a
flux-density of 7.2mJy. It targets the ESO Imaging Survey (EIS) Patch D, which
is a 3 by 2 square degree field centred on 09 51 36.0 -21 00 00 (J2000). This
paper presents K-band imaging of 142 of the 150 CENSORS sources. The primary
motivation for beginning infrared imaging of the sample was to identify the
host galaxies of the ~30% of sources for which the EIS I-band imaging failed to
produce a likely candidate. In addition, K-band magnitudes allow photometric
redshift estimation and I - K colours aid the identification of host galaxies
(which are typically old, red ellipticals). Of the sources observed in the I
and K-bands, four remain undetected, possibly indicating high redshifts for the
host galaxies, and eight involve complicated radio structures, or several
candidate host galaxies, which have yet to be resolved. Thus, the host galaxy
identifications are brought to 92% completeness.
  In conjunction with spectroscopic observations, the K-band magnitudes have
been aperture corrected and used to establish a K-z relation for the CENSORS
radio galaxies. This relation is of interest because of its variation, at z >
1, between radio surveys of different flux-density limit. Establishing this
relation for CENSORS may shed light on the origin of this variation and will
allow an appropriate K-z redshift estimator for any CENSORS source which
remains without a spectroscopic redshift. It is shown that whilst the K-z
relation for CENSORS is fainter than that of 3CRR at all redshifts, it agrees
well with that of 7C over all redshifts studied.


title:
Spitzer Observations of the Brightest Galaxies in X-ray-Luminous
  Clusters

abstract:
  We have studied the infrared properties of the brightest cluster galaxies
(BCGs) located in the cores of X-ray-luminous clusters at 0.15 < z < 0.35. The
majority of the BCGs are not particularly infrared-luminous compared with other
massive early-type galaxies, suggesting that the cluster environment has little
influence on the infrared luminosities of the BCGs. The exceptions, however,
are the BCGs in the three X-ray-brightest clusters in the sample, A1835, Z3146,
and A2390. These BCGs have a prominent far-infrared peak in their spectral
energy distributions (SEDs), and two of them (those in A1835 and Z3146) can be
classified as luminous infrared galaxies (LIRGs: L_{IR} > 10^{11} L_{sun}).
Although radio AGNs are found to be prevalent among the BCGs, the infrared
luminosities of these three BCGs, judged from the infrared SED signatures, are
likely to be powered by star formation. Considering the overall trend that
clusters with shorter radiative gas cooling times harbor more infrared-luminous
BCGs, the enhanced star formation may be caused by the cooling cluster gas
accreting onto the BCGs.


title: Spitzer Massive Lensing Cluster Survey

abstract:
  We are currently undertaking a Spitzer GTO program to image ~30 massive
lensing clusters at moderate redshift with both IRAC and MIPS. By taking
advantage of the gravitatinoal lensing power of these clusters, we will study
the population of faint galaxies that are below the nominal Spitzer detection
limits. Here, we present a few examples of our science programs.


title: The Swift X-ray flaring afterglow of GRB 050607

abstract:
  The unique capability of the Swift satellite to perform a prompt and
autonomous slew to a newly detected Gamma-Ray Burst (GRB) has yielded the
discovery of interesting new properties of GRB X-ray afterglows, such as the
steep early lightcurve decay and the frequent presence of flares detected up to
a few hours after the GRB trigger. We present observations of GRB 050607, the
fourth case of a GRB discovered by Swift with flares superimposed on the
overall fading X-ray afterglow. The flares of GRB 050607 were not symmetric as
in previously reported cases, showing a very steep rise and a shallower decay,
similar to the Fast Rise, Exponential Decay that are frequently observed in the
gamma-ray prompt emission. The brighter flare had a flux increase by a factor
of approximately 25,peaking for 30 seconds at a count rate of approximately 30
counts s-1, and it presented hints of addition short time scale activity during
the decay phase. There is evidence of spectral evolution during the flares. In
particular, at the onset of the flares the observed emission was harder, with a
gradual softening as each flare decayed. The very short time scale and the
spectral variability during the flaring activity are indicators of possible
extended periods of energy emission by the GRB central engine. The flares were
followed by a phase of shallow decay, during which the forward shock was being
refreshed by a long-lived central engine or by shells of lower Lorentz factors,
and by a steepening after approximately 12 ks to a decay slope considered
typical of X-ray afterglows.


title: Annihilation Emission from the Galactic Black Hole

abstract:
  Both diffuse high energy gamma-rays and an extended electron-positron
annihilation line emission have been observed in the Galactic Center (GC)
region. Although X-ray observations indicate that the galactic black hole Sgr
A$^*$ is inactive now, we suggest that Sgr A$^*$ can become active when a
captured star is tidally disrupted and matter is accreted into the black hole.
As a consequence the galactic black hole could be a powerful source of
relativistic protons. We are able to explain the current observed diffuse
gamma-rays and the very detailed 511 keV annihilation line of secondary
positrons by $p-p$ collisions of such protons, with appropriate injection times
and energy. Relativistic protons could have been injected into the ambient
material if the black hole captured a 50M$_\odot$ star at several tens million
years ago. An alternative possibility is that the black hole continues to
capture stars with $\sim$1M$_\odot$ every hundred thousand years. Secondary
positrons produced by $p-p$ collisions at energies $\ga 30$ MeV are cooled down
to thermal energies by Coulomb collisions, and annihilate in the warm neutral
and ionized phases of the interstellar medium with temperatures about several
eV, because the annihilation cross-section reaches its maximum at these
temperatures. It takes about ten million years for the positrons to cool down
to thermal temperatures so they can diffuse into a very large extended region
around the Galactic center. A much more recent star capture may be also able to
account for recent TeV observations within 10 pc of the galactic center as well
as for the unidentified GeV gamma-ray sources found by EGRET at GC. The
spectral difference between the GeV flux and the TeV flux could be explained
naturally in this model as well.


title: Where to find a dark matter sterile neutrino?

abstract:
  We propose a strategy of how to look for dark matter (DM) particles
possessing a radiative decay channel and derive constraints on their parameters
from observations of X-rays from our own Galaxy and its dwarf satellites. When
applied to the sterile neutrinos in keV mass range, it allows a significant
improvement of restrictions to its parameters, as compared with previous works.


title: Sterile neutrinos in the Milky Way: Observational constraints

abstract:
  We consider the possibility of constraining decaying dark matter by looking
out through the Milky Way halo. Specifically we use Chandra blank sky
observations to constrain the parameter space of sterile neutrinos. We find
that a broad band in parameter space is still open, leaving the sterile
neutrino as an excellent dark matter candidate.


title:
Testing Gaussian random hypothesis with the cosmic microwave background
  temperature anisotropies in the three-year WMAP data

abstract:
  We test the hypothesis that the temperature of the cosmic microwave
background is consistent with a Gaussian random field defined on the celestial
sphere, using de-biased internal linear combination (DILC) map produced from
the 3-year WMAP data. We test the phases for spherical harmonic modes with l <=
10 (which should be the cleanest) for their uniformity, randomness, and
correlation with those of the foreground templates. The phases themselves are
consistent with a uniform distribution, but not for l <= 5, and the differences
between phases are not consistent with uniformity. For l=3 and l=6, the phases
of the CMB maps cross-correlate with the foregrounds, suggestion the presence
of residual contamination in the DLC map even on these large scales. We also
use a one-dimensional Fourier representation to assemble a_lm into the \Delta
T_l(\phi) for each l mode, and test the positions of the resulting maxima and
minima for consistency with uniformity randomness on the unit circle. The
results show significant departures at the 0.5% level, with the one-dimensional
peaks being concentrated around \phi=180 degs. This strongly significant
alignment with the Galactic meridian, together with the cross-correlation of
DILC phases with the foreground maps, strongly suggests that even the lowest
spherical harmonic modes in the map are significantly contaminated with
foreground radiation.


title: A model for the metallicity evolution of damped Lyman-alpha systems

abstract:
  We apply a physically motivated stellar feedback model to analyse the
statistical properties of damped Lyman-alpha systems (DLAs) expected in the
concordance cold dark matter (CDM) model. Our feedback model produces extended
low-metallicity cold gaseous discs around small galaxies. Since the space
density of galaxies with low circular speeds is high, these discs dominate the
cross-section for the identification of DLAs at all redshifts. The combined
effects of star formation, outflows and infall in our models result in mild
evolution of the N_{HI}-weighted metallicity content in DLAs with redshift,
consistent with observations. According to our model, DLAs contribute only a
small fraction of the volume averaged star formation rate at redshifts z \simlt
5. Our model predicts weak evolution in Omega_{HI} over the redshift range
z=0-5. Furthermore, we show that the cosmological evolution of Omega_{HI} and
the cosmic star formation rate are largely disconnected and conclude that the
evolution of Omega_{HI} as a function of redshift is more likely to tell us
about feedback processes and the evolution of the outer gaseous components of
small galaxies than about the cosmic history of star formation.


title: On the evolution of the resonant planetary system HD128311

abstract:
  A significant number of the known multiple exoplanetary systems are
containing a pair of giant planets engaged in a low order mean motion
resonance. Such a resonant condition protects the dynamics of these planets
resulting in very stable orbits. According to recent studies the capture into a
resonance is the result of a planetary migration process induced by the
interaction of the planets with a protoplanetary disk. If the migration is slow
enough (adiabatic) next to a mean motion resonance, the two planets will also
be in apsidal corotation.
  The recently refined orbital parameters of the system HD 128311 suggest that
the two giant planets are in a 2:1 mean motion resonance, however without
exhibiting apsidal corotation. Thus the evolution of this system can not be
described by an adiabatic migration process alone.
  We present possible evolution scenarios of this system combining migration
processes and sudden perturbations. We model migration scenarios through
numerical integration of the gravitational N-body problem with additional
non-conservative forces. Planet-planet scattering has been investigated by
N-body simulations.
  We show that the present dynamical state of the system HD128311 may be
explained by such evolutionary processes.


title: Archeops In-flight Performance, Data Processing and Map Making

abstract:
  Archeops is a balloon--borne experiment widely inspired by the Planck
satellite and by its High Frequency Instrument (HFI). It is mainly dedicated to
measure the Cosmic Microwave Background (CMB) temperature anisotropies at high
angular resolution (about 12 arcminutes) over a large fraction of the sky
(around 30 %) in the millimetre and submillimetre range at 143, 217, 353 and
545 GHz. Further, the Archeops 353 GHz channel consists of three pairs of
polarized sensitive bolometers designed to detect the polarized diffuse
emission of Galactic dust. We present in this paper the update of the
instrumental setup as well as the inflight performance for the last Archeops
flight campaign in February 2002 from Kiruna (Sweden). We also describe the
processing and analysis of the Archeops time ordered data for that campaign
which lead to the measurement of the CMB anisotropies power spectrum in the
multipole range l=10-700 (Benoit et al. 2003a, Tristram et al. 2005) and to the
first measurement of the dust polarized emission at large angular scales and
its polarized. We present maps of 30 % of the sky of the Galactic emission,
including the Galactic plane, in the four Archeops channels at 143, 217, 353
and 545 GHz and maps of the CMB anisotropies at 143 and 217 GHz. These are the
firstever available sub--degree resolution maps in the millimetre and
submillimetre range of the large angular-scales Galactic dust diffuse emission
and CMB temperature anisotropies respectively.


title: Brane World Dynamics and Adiabatic Matter creation

abstract:
  We have treated the adiabatic matter creation process in various three-brane
models by applying thermodynamics of open systems. The matter creation rate is
found to affect the evolution of scale factor and energy density of the
universe. We find modification at early stages of cosmic dynamics. In GB and RS
brane worlds, by chosing appropriate parameters we obtain standard scenario,
while the warped DGP model has different Friedmann equations. During later
stages, since the matter creation is negligible the evolution reduces to FRW
expansion, in RS and GB models.


title:
Discovery of an Optically Thick, Edge-on Disk around the Herbig Ae star
  PDS 144N

abstract:
  We have discovered an optically thick, edge-on circumstellar disk around a
Herbig Ae star in the binary system PDS 144, providing the first
intermediate-mass analog of HK Tau and similar T Tauris. This system consists
of a V ~ 13 mag. primary and a fainter companion, with spectra of both stars
showing evidence for circumstellar disks and accretion; both stars were
classified as Herbig Aes by the Pico dos Dias survey. In Lick adaptive optics
polarimetry, we resolved extended polarized light scattered from dust around
the northern star. Followup Keck adaptive optics and mid-infrared observations
show that this star is entirely hidden by an optically thick disk at all
wavelengths from 1.2 to 11.7 microns. The disk major axis subtends ~ 0.8" on
the sky, corresponding to ~ 800 AU at a distance of 1000 pc. Bright "wings"
extend 0.3" above and below the disk ansae, due most likely to scattering from
the edges of an outflow cavity in a circumstellar envelope. We discuss the
morphology of the disk and the spectral energy distributions of the two PDS 144
stars, present preliminary disk models, and identify a number of open questions
regarding this fascinating system.


title:
Modelling Chromospheric Line Profiles in NGC2808: Evidence of Mass Loss
  from RGB Stars

abstract:
  In this study we test the possibility that the asymmetry in the profiles of
the H-alpha and Ca II K lines in red giant stars is due to the presence of an
active chromosphere rather than to mass loss. To this end, we compare line
profiles computed using relevant model chromospheres to profiles of the H-alpha
and Ca II K lines observed in five red giant stars of the globular cluster NGC
2808. The spectra were taken with FLAMES during Science Verification, using the
UVES mode at high resolution (R=43,000) for the H-alpha line, and GIRAFFE in
MEDUSA mode (R=20,000) for the Ca II K line. We find that the observed profiles
are better described if a negative (outward) velocity field is included in the
model chromospheres. This leads to mass loss rates of a few 10**(-9) solar
masses per year, very close to the requirements of the stellar evolution
theory.


title: Measuring 26Al and 60Fe in the Galaxy

abstract:
  With the SPI high-resolution spectrometer on INTEGRAL, new results have been
obtained for long-lived radioactive 26Al and 60Fe in our Galaxy: 26Al sources
apparently share the pattern of Galactic rotation in the inner Galaxy, and thus
allow to estimate a total mass of 26Al in the Galaxy of 2.8 M_sol from the
measured flux. 60Fe production in massive stars is constrained by recent
gamma-ray detections, and appears to be lower than predicted by standard
models. We show the broader implications of these findings both for the study
of our Galaxy, and for nucleosynthesis in massive stars.


title: SN 2004A: Another Type II-P Supernova with a Red Supergiant Progenitor

abstract:
  We present a monitoring study of SN 2004A and probable discovery of a
progenitor star in pre-explosion HST images. The photometric and spectroscopic
monitoring of SN 2004A show that it was a normal Type II-P which was discovered
in NGC 6207 about two weeks after explosion. We compare SN 2004A to the similar
Type II-P SN 1999em and estimate an explosion epoch of 2004 January 6. We also
calculate three new distances to NGC 6207 of 21.0 +/-4.3, 21.4 +/-3.5 and 25.1
+/-1.7Mpc. The former was calculated using the Standard Candle Method (SCM) for
SNe II-P, and the latter two from the Brightest Supergiants Method (BSM). We
combine these three distances with existing kinematic distances, to derive a
mean value of 20.3 +/-3.4Mpc. Using this distance we estimate that the ejected
nickel mass in the explosion is 0.046(+0.031,-0.017) Msolar. The progenitor of
SN 2004A is identified in pre-explosion WFPC2 F814W images with a magnitude of
mF814W = 24.3 +/-0.3, but is below the detection limit of the F606W images. We
show that this was likely a red supergiant (RSG) with a mass of 9(+3,-2)
Msolar. The object is detected at 4.7 sigma above the background noise. Even if
this detection is spurious, the 5 sigma upper limit would give a robust upper
mass limit of 12 Msolar for a RSG progenitor. These initial masses are very
similar to those of two previously identified RSG progenitors of the Type II-P
SNe 2004gd 8(+4,-2) Msolar and 2005cs 9(+3,-2) Msolar).


title:
Rotation speed and stellar axis inclination from p modes: How CoRoT
  would see other suns

abstract:
  In the context of future space-based asteroseismic missions, we have studied
the problem of extracting the rotation speed and the rotation-axis inclination
of solar-like stars from the expected data. We have focused on slow rotators
(at most twice solar rotation speed), firstly because they constitute the most
difficult case and secondly because some of the CoRoT main targets are expected
to have slow rotation rates. Our study of the likelihood function has shown a
correlation between the estimates of inclination of the rotation axis i and the
rotational splitting deltanu of the star. By using the parameters, i and
deltanu*=deltanu sin(i), we propose and discuss new fitting strategies. Monte
Carlo simulations have shown that we can extract a mean splitting and the
rotation-axis inclination down to solar rotation rates. However, at the solar
rotation rate we are not able to correctly recover the angle i although we are
still able to measure a correct deltanu* with a dispersion less than 40 nHz.


title:
Line profiles of water for the photon dominated region and embedded
  sources in the S140 region

abstract:
  A radiative transfer method for the treatment of molecular lines is
presented. We apply this method to previous SWAS and ISO observations of water
vapor in the source S140 in order to make models to plan for, and to interpret,
HIFI data. Level populations are calculated with the use of a three-dimensional
(multi-zone) escape probability method and with a long characteristic code that
uses Monte Carlo techniques with fixed directions. Homogeneous and
inhomogeneous models are used to compute the differences between water line
profiles across the S140 region. We find that when an outflow or infall
velocity field with a gradient of a few kms^{-1} is adopted, line profiles with
a FWHM of 6 kms^{-1} are found, in agreement with observations. Inhomogeneous
models are favoured to produce a single-peaked line profile. When zooming in on
smaller regions within the PDR, the shapes of the line profiles start to differ
due to the different temperature and density distributions there. The embedded
sources are traced by high excitation lines of, e.g., 3_{21}-2_{21},
3_{03}-2_{12}, 2_{12}-1_{01} and 2_{20}-1_{11}. The computed intensities are
roughly consistent with existing ISO observations. Water emission in a PDR
source like S140 requires a combination of a pure PDR and an embedded source in
order to match the observations. Because of its good angular resolution, HIFI
will be able to distinguish between a dense star forming region or a more
diffuse gas component. It is therefore important for future observing programs
to consider both in their predictions of the emission characteristics of water
in these environments.


title: The Rotation of Young Low-Mass Stars and Brown Dwarfs

abstract:
  We review the current state of our knowledge concerning the rotation and
angular momentum evolution of young stellar objects and brown dwarfs from a
primarily observational view point. Periods are typically accurate to 1% and
available for about 1700 stars and 30 brown dwarfs in young clusters.
Discussion of angular momentum evolution also requires knowledge of stellar
radii, which are poorly known for pre-main sequence stars. It is clear that
rotation rates at a given age depend strongly on mass; higher mass stars
(0.4-1.2 M$_\odot$) have longer periods than lower mass stars and brown dwarfs.
On the other hand, specific angular momentum is approximately independent of
mass for low mass pre-main sequence stars and young brown dwarfs. A spread of
about a factor of 30 is seen at any given mass and age. The evolution of
rotation of solar-like stars during the first 100 Myr is discussed. A broad,
bimodal distribution exists at the earliest observable phases ($\sim$1 Myr) for
stars more massive than 0.4 M$_\odot$. The rapid rotators (50-60% of the
sample) evolve to the ZAMS with little or no angular momentum loss. The slow
rotators continue to lose substantial amounts of angular momentum for up to 5
Myr, creating the even broader bimodal distribution characteristic of 30-120
Myr old clusters. Accretion disk signatures are more prevalent among slowly
rotating PMS stars, indicating a connection between accretion and rotation.
Disks appear to influence rotation for, at most, $\sim$5 Myr, and considerably
less than that for the majority of stars. If the dense clusters studied so far
are an accurate guide, then the typical solar-like star may have only $\sim$1
Myr for this task. It appears that both disk interactions and stellar winds are
less efficient at braking these objects.


title:
Perturbations of ionization fractions at the cosmological recombination
  epoch

abstract:
  A development of perturbations of number densities of ions and electrons
during recombination epoch is analysed. The equations for relative
perturbations of ionization fractions were derived from the system of equations
for accurate computation of the ionization history of the early Universe given
by Seager et al. (1999,2000). It is shown that strong dependence of ionization
and recombination rates on the density and temperature of plasma provides the
significant deviations of amplitudes of ionization fractions relative
perturbations from ones of baryon matter density adiabatic perturbations. Such
deviations are most prominent for cosmological adiabatic perturbations of
scales larger than sound horizon at recombination epoch. The amplitudes of
relative perturbations of number densities of electrons and protons at last
scattering surface exceed by factor of $\simeq$5 the amplitude of relative
perturbation of baryons total number density, for helium ions this ratio
reaches the value of $\simeq$18. For subhorizon cosmological perturbations
these ratios appear to be essentially lesser and depend on oscillation phase at
the moment of decoupling. These perturbations of number densities of ions and
electrons at recombination epoch do not contribute to the intrinsic plasma
temperature fluctuations but cause the ''corrugation'' of last scattering
surface in optical depth, $\delta z_{dec}/(z_{dec}+1)\approx -\delta_b/3$, at
scales larger than sound horizon. It may result into noticeable changes of
precalculated values of CMB polarization pattern at several degrees angular
scales.


title:
CRPropa: A Numerical Tool for the Propagation of UHE Cosmic Rays,
  Gamma-rays and Neutrinos

abstract:
  To understand the origin of ultra-high energy cosmic rays (UHECRs, defined to
be above 10^18 eV), it is required to model in a realistic way their
propagation in the Universe. UHECRs can interact with low energy radio,
microwave, infrared and optical photons to produce electron/positron pairs or
pions. The latter decay and give rise to neutrinos and electromagnetic cascades
extending down to MeV energies. In addition, deflections in cosmic magnetic
fields can influence the spectrum and sky distribution of primary cosmic rays
and, due to the increased propagation path length, the secondary neutrino and
gamma-ray fluxes. Neutrino, gamma-ray, cosmic ray physics and extra-galactic
magnetic fields are, therefore, strongly linked subjects and should be
considered together in order to extract maximal information from existing and
future data, like the one expected from the Auger Observatory. For that
purpose, we have developed CRPropa, a publicly-available numerical package
which takes into account interactions and deflections of primary UHECRs as well
as propagation of secondary electromagnetic cascades and neutrinos. CRPropa
allows to compute the observable properties of UHECRs and their secondaries in
a variety of models for the sources and propagation of these particles. Here we
present physical processes taken into account as well as benchmark examples; a
detailed documentation of the code can be found on our web site.


title:
The Importance of Phase in Nulling Interferometry and a Three Telescope
  Closure-Phase Nulling Interferometer Concept

abstract:
  We discuss the theory of the Bracewell nulling interferometer and explicitly
demonstrate that the phase of the "white light" null fringe is the same as the
phase of the bright output from an ordinary stellar interferometer. As a
consequence a "closure phase" exists for a nulling interferometer with three or
more telescopes. We calculate the phase offset as a function of baseline length
for an Earth-like planet around the Sun at 10 pc, with a contrast ratio of
$10^{-6}$ at 10 $\mu$m. The magnitude of the phase due to the planet is $\sim
10^{-6}$ radians, assuming the star is at the phase center of the array.
Although this is small, this phase may be observable in a three-telescope
nulling interferometer that measures the closure phase. We propose a simple
non-redundant three-telescope nulling interferometer that can perform this
measurement. This configuration is expected to have improved characteristics
compared to other nulling interferometer concepts, such as a relaxation of
pathlength tolerances, through the use of the "ratio of wavelengths" technique,
a closure phase, and better discrimination between exodiacal dust and planets.


title:
An Efficient Method for the Evaluation of Secular Effects in the
  Perturbed Keplerian Motion

abstract:
  Binary systems subject to generic perturbations evolve on quasiperiodic
orbits. We derive the most generic class of perturbations, which allow to
evaluate secular effects via generalized complex true and eccentric anomaly
parameters, by use of the residue theorem. Such perturbations include both the
generic Brumberg force and various linear contributions to the conservative
dynamics of compact binaries, up to the second post-Newtonian order. As an
example, we compute the self-spin contribution to the luminosity due to
gravitational radiation of a compact binary consisting of galactic black holes,
the most important type of source for LISA. This translates to simply calculate
the residue of the instantaneous energy loss in the origin of the complex
parameter plane, which illustrates the power of the presented method.


abstract:
  We examine the X-ray and infrared properties of galaxies and AGNs in the 9
square degree Bootes field, using data from the Chandra XBootes and Spitzer
IRAC Shallow Surveys, as well as optical spectroscopy from the AGES survey. A
sample of ~30,000 objects are detected in all four IRAC bands, of which ~2,000
are associated with X-ray sources. We also study X-ray fainter sources using
stacking techniques, and find that X-ray fluxes are highest for objects with
IRAC colors that are known to be characteristic of AGNs. Because these are
shallow, wide-field surveys, they probe the bright end of the AGNluminosity
function out to spectroscopic redshifts as high as z=3-4. We can use this
multiwavelength dataset to explore the properties and redshift evolution of a
large sample of luminous active galaxies.


title: The nature of (sub)-mm galaxies in hierarchical models

abstract:
  We present a hierarchical galaxy formation model which can account for the
number counts of sources detected through their emission at sub-millimetre
wavelengths. The first stage in our approach is an ab initio calculation of the
star formation histories for a representative sample of galaxies, which is
carried out using the semi-analytical galaxy formation model GALFORM. These
star formation histories are then input into the spectro-photometric code
GRASIL, to produce a spectral energy distribution for each galaxy. Dust
extinction and emission are treated self consistently in our model, without
having to resort to ad-hoc assumptions about the amount of attenuation by dust
or the temperature at which the dust radiates. We argue that it is necessary to
modify the form of the stellar initial mass function in starbursts in order to
match the observed number of sub-mm sources, if we are to retain the previous
good matches enjoyed between observations and model predictions in the local
universe. We also list some other observational tests that have been passed by
our model.


title: Radio-loud Narrow-Line Type 1 Quasars

abstract:
  We present the first systematic study of (non-radio-selected) radio-loud
narrow-line Seyfert 1 (NLS1) galaxies. Cross-correlation of the `Catalogue of
Quasars and Active Nuclei' with several radio and optical catalogues led to the
identification of 11 radio-loud NLS1 candidates including 4 previously known
ones. Most of the radio-loud NLS1s are compact, steep spectrum sources
accreting close to, or above, the Eddington limit. The radio-loud NLS1s of our
sample are remarkable in that they occupy a previously rarely populated regime
in NLS1 multi-wavelength parameter space. While their [OIII]/H_beta and
FeII/H_beta intensity ratios almost cover the whole range observed in NLS1
galaxies, their radio properties extend the range of radio-loud objects to
those with small widths of the broad Balmer lines. Among the radio-detected
NLS1 galaxies, the radio index R distributes quite smoothly up to the critical
value of R ~ 10 and covers about 4 orders of magnitude in total. Statistics
show that ~7% of the NLS1 galaxies are formally radio-loud while only 2.5%
exceed a radio index R > 100. Several mechanisms are considered as explanations
for the radio loudness of the NLS1 galaxies and for the lower frequency of
radio-louds among NLS1s than quasars. While properties of most sources (with
2-3 exceptions) generally do not favor relativistic beaming, the combination of
accretion mode and spin may explain the observations. (abbreviated)


title:
Astrometric Detection of Terrestrial Planets in the Habitable Zones of
  Nearby Stars with SIM PlanetQuest

abstract:
  SIM PlanetQuest (Space Interferometry Mission) is a space-borne Michelson
interferometer for precision stellar astrometry, with a nine meter baseline,
currently slated for launch in 2015. One of the principal science goals is the
astrometric detection and orbit characterization of terrestrial planets in the
habitable zones of nearby stars. Differential astrometry of the target star
against a set of reference stars lying within a degree will allow measurement
of the target star's reflex motion with astrometric accuracy of 1
micro-arcsecond in a single measurement.
  We assess SIM's capability for detection (as opposed to characterization by
orbit determination) of terrestrial planets in the habitable zones of nearby
solar-type stars. We compare SIM's performance on target lists optimized for
the SIM and Terrestrial Planet Finder Coronograph (TPF-C) missions. Performance
is quantified by three metrics: minimum detectable planet mass, number and mass
distribution of detected planets, and completeness of detections in each mass
range. Finally, we discuss the issue of confidence in detections and
non-detections, and show how information from SIM's planet survey can enable
TPF to increase its yield of terrestrial planets.


title:
The structure of galactic disks: Studying late-type spiral galaxies
  using SDSS

abstract:
  Using imaging data from the SDSS survey, we present the g' and r' radial
stellar light distribution of a complete sample of ~90 face-on to intermediate
inclined, nearby, late-type (Sb-Sdm) spiral galaxies. The surface brightness
profiles are reliable (1sigma uncertainty less than 0.2 mag) down to
mu=~27magsqarcsec. Only ~10% of all galaxies have a normal/standard purely
exponential disk down to our noise limit.
  The surface brightness distribution of the rest of the galaxies is better
described as a broken exponential. About 60% of the galaxies have a break in
the exponential profile between ~1.5-4.5 times the scalelength followed by a
downbending, steeper outer region. Another ~30% shows also a clear break
between ~4.0-6.0 times the scalelength but followed by an upbending, shallower
outer region. A few galaxies have even a more complex surface brightness
distribution.
  The shape of the profiles correlates with Hubble type. Downbending breaks are
more frequent in later Hubble types while the fraction of upbending breaks
rises towards earlier types. No clear relation is found between the
environment, as characterised by the number of neighbours, and the shape of the
profiles of the galaxies.


title: Testing RIAF model for Sgr A* using the size measurements

abstract:
  Recent radio observations by the VLBA at 7 and 3.5 mm produced the
high-resolution images of the compact radio source located at the center of our
Galaxy--Sgr A*, and detected its wavelength-dependent intrinsic sizes at the
two wavelengths. This provides us with a good chance of testing
previously-proposed theoretical models for Sgr A*. In this {\em Letter}, we
calculate the size based on the radiatively inefficient accretion flow (RIAF)
model proposed by Yuan, Quataert & Narayan (2003). We find that the predicted
sizes after taking into account the scattering of the interstellar electrons
are consistent with the observations. We further predict an image of Sgr A* at
1.3 mm which can be tested by future observations.


title: The Environmental Impact of Lyman-break Galaxies

abstract:
  We perform cosmological simulations of galaxies forming at z=3 using the
hydrodynamics grid code, Enzo. By selecting the largest galaxies in the volume
to correspond to Lyman-break galaxies, we construct observational spectra of
the HI flux distribution around these objects, as well as column densities of
CIV and OVI throughout a refined region. We successfully reproduce the most
recent observations of the mean HI flux in the close vicinity of Lyman-break
galaxies but see no evidence for the proximity effect in earlier observations.
While our galaxies do return metals to the IGM, their quantity and volume
appears to be somewhat less than observed. We conclude that either we do not
adequately resolve galactic winds, or that at least some of the intergalactic
metal enrichment is by early epoch objects whose mass is smaller than our
minimum resolved halo mass.


title:
Flaring Activity of Sgr A* at 43 and 22 GHz: Evidence for Expanding Hot
  Plasma

abstract:
  We have carried out Very Large Array (VLA) continuum observations to study
the variability of Sgr A* at 43 GHz ($\lambda$=7mm) and 22 GHz
($\lambda$=13mm). A low level of flare activity has been detected with a
duration of $\sim$ 2 hours at these frequencies, showing the peak flare
emission at 43 GHz leading the 22 GHz peak flare by $\sim20$ to 40 minutes. The
overall characteristics of the flare emission are interpreted in terms of the
plasmon model of Van der Laan (1966) by considering the ejection and
adiabatically expansion of a uniform, spherical plasma blob due to flare
activity. The observed peak of the flare emission with a spectral index
$\nu^{-\alpha}$ of $\alpha$=1.6 is consistent with the prediction that the peak
emission shifts toward lower frequencies in an adiabatically-expanding
self-absorbed source. We present the expected synchrotron light curves for an
expanding blob as well as the peak frequency emission as a function of the
energy spectral index constrained by the available flaring measurements in
near-IR, sub-millimeter, millimeter and radio wavelengths. We note that the
blob model is consistent with the available measurements, however, we can not
rule out the jet of Sgr A*. If expanding material leaves the gravitational
potential of Sgr A*, the total mass-loss rate of nonthermal and thermal
particles is estimated to be $\le 2\times10^{-8}$ M$_\odot$ yr$^{-1}$. We
discuss the implication of the mass-loss rate since this value matches closely
with the estimated accretion rate based on polarization measurements.


title: GRB 060218/SN 2006aj: A Gamma-Ray Burst and Prompt Supernova at z=0.0335

abstract:
  We report the imaging and spectroscopic localization of GRB 060218 to a
low-metallicity dwarf starburst galaxy at z = 0.03345 +/- 0.00006. In addition
to making it the second nearest gamma-ray burst known, optical spectroscopy
reveals the earliest detection of weak, supernova-like Si II near 5720
Angstroms (0.1c), starting 1.95 days after the burst trigger. UBVRI photometry
obtained between 1 and 26 days post-burst confirms the early rise of supernova
light, and suggests a short time delay between the gamma-ray burst and the
onset of SN 2006aj if the early appearance of a soft component in the X-ray
spectrum is understood as a ``shock breakout''. Together, these results verify
the long-hypothesized origin of soft gamma-ray bursts in the deaths of massive
stars.


title: Persistent Patterns in Accretion Disks

abstract:
  We present a set of new characteristic frequencies associated with accretion
disks around compact objects. These frequencies arise from persistent rotating
patterns in the disk that are finite in radial extent and driven purely by the
gravity of the central body. Their existence depends on general relativistic
corrections to orbital motion and, if observed, could be used to probe the
strong gravity region around a black hole. We also discuss a possible
connection to the puzzle of quasi-periodic oscillations.


title:
The NOAO Fundamental Plane Survey - III. Variations in the stellar
  populations of red-sequence galaxies from the cluster core to the virial
  radius

abstract:
  We analyse absorption line-strength indices for ~3000 red-sequence galaxies
in 94 nearby clusters, to investigate systematic variations of their stellar
content with location in the host cluster. The data are drawn from the NOAO
Fundamental Plane Survey. Our adopted method is a generalization of that
introduced by Nelan et al. to determine the global age-mass and
metallicity-mass relations from the same survey. We find strong evidence for a
change in galaxy properties, at fixed mass, over a range from the cluster
centre to the virial radius, R_200. For example, red-sequence galaxies further
out in the clusters have weaker Mgb5177 (at ~8 sigma significance) and stronger
Hbeta and Hgamma absorption (~3 sigma, ~4 sigma) than galaxies of the same
velocity dispersion in the cluster cores. The Fe5270 and Fe5335 indices show
only very weak trends with radius. Using a total of twelve indices, the pattern
of cluster-centric gradients is considered in light of their different
dependences on stellar age and chemical composition. The measured gradients for
all twelve indices can be reproduced by a model in which red-sequence galaxies
at ~1 R_200 have on average younger ages (by 15+/-4%) and lower alpha-element
abundance ratios (by 10+/-2%), than galaxies of the same velocity dispersion
but located near the cluster centre. For the total metallicity, Z/H, no
significant gradient is found (2+/-3% larger at R_200 than in the core). The
cluster-centric age and alpha/Fe gradients are in the sense expected if
galaxies in the cluster core were accreted at an earlier epoch than those at
larger radii, and if this earlier accretion contributed to an earlier cessation
of star formation. The size of the observed age trend is comparable to
predictions from semi-analytic models of hierarchical galaxy formation.


title:
HST and Spitzer Observations of the Host Galaxy of GRB 050904: A
  Metal-Enriched, Dusty Starburst at z=6.295

abstract:
  We present deep Hubble Space Telescope and Spitzer Space Telescope
observations of the host galaxy of GRB 050904 at z=6.295. The host is detected
in the H-band and marginally at 3.6 micron. From these detections, and limits
in the z'-band and 4.5 micron, we infer an extinction-corrected absolute
magnitude, M(UV)=-20.7 mag, or ~L*, a substantial star formation rate of 15
solar masses per year, and a stellar mass of a few 10^9 solar masses. A
comparison to the published sample of spectroscopically-confirmed galaxies at
z>5.5 reveals that the host of GRB 050904 would evade detection and/or
confirmation in any of the current surveys due to the lack of detectable
Ly-alpha emission, which is likely the result of dust extinction (A[1200]~1.5
mag). This suggests that not all luminous starburst galaxies at z~6 are
currently being accounted for. Most importantly, using the metallicity of
Z~0.05 solar inferred from the afterglow absorption spectrum, our observations
indicate for the first time that the observed evolution in the mass- and
luminosity-metallicity relations from z=0 to z~2 continues on to z>6. The ease
of measuring redshifts and metallicities from the afterglow emission suggests
that in tandem with the next generation ground- and space-based telescopes, a
GRB mission with dedicated near-IR follow-up can provide unique information on
the evolution of stars and galaxies through the epoch of re-ionization.


title:
Cross-correlation of WMAP 3rd year and the SDSS DR4 galaxy survey: new
  evidence for Dark Energy

abstract:
  We cross-correlate the third-year WMAP data with galaxy samples extracted
from the SDSS DR4 (SDSS4) covering 13% of the sky, increasing by a factor of
3.7 the volume sampled in previous analyses. The new measurements confirm a
positive cross-correlation with higher significance (total signal-to-noise of
about 4.7). The correlation as a function of angular scale is well fitted by
the integrated Sachs-Wolfe (ISW) effect for LCDM flat FRW models with a
cosmological constant. The combined analysis of different samples gives
Omega_L=0.80-0.85$ (68% Confidence Level, CL) or $0.77-0.86$ (95% CL). We find
similar best fit values for Omega_L for different galaxy samples with median
redshifts of z ~0.3 and z ~0.5, indicating that the data scale with redshift as
predicted by the LCDM cosmology (with equation of state parameter w=-1). This
agreement is not trivial, but can not yet be used to break the degeneracy
constraints in the w versus Omega_L plane using only the ISW data.


title: Improved 3D Fabry-Perot Data Reduction Techniques

abstract:
  Improved data reduction techniques for 3D data cubes obtained from
Fabry-Perot integral field spectroscopy are presented. They provide accurate
sky emission subtraction and adaptive spatial binning and smoothing. They help
avoiding the effect analogous to the beam smearing, seen in HI radio data, when
strong smoothing is applied to 3D data in order to get the most extended signal
coverage. The data reduction techniques presented in this paper allow one to
get the best of both worlds: high spatial resolution in high signal-to-noise
regions and large spatial coverage in low signal-to-noise regions.


title: Structures in the Great Attractor Region

abstract:
  To further our understanding of the Great Attractor (GA), we have undertaken
a redshift survey using the 2dF on the AAT. Clusters and filaments in the GA
region were targeted with 25 separate pointings resulting in approximately 2600
new redshifts. Targets included poorly studied X-ray clusters from the CIZA
catalogue as well as the Cen-Crux and PKS 1343-601 clusters, both of which lie
close to the classic GA centre. For nine clusters in the region, we report
velocity distributions as well as virial and projected mass estimates. The
virial mass of CIZA J1324.7-5736, now identified as a separate structure from
the Cen-Crux cluster, is found to be ~3x10^14 M_sun, in good agreement with the
X-ray inferred mass. In the PKS 1343-601 field, five redshifts are measured of
which four are new. An analysis of redshifts from this survey, in combination
with those from the literature, reveals the dominant structure in the GA region
to be a large filament, which appears to extend from Abell S0639 (l=281\deg,
b=+11\deg) to (l~5\deg, b~-50\deg), encompassing the Cen-Crux, CIZA
J1324.7-5736, Norma and Pavo II clusters. Behind the Norma Cluster at cz~15000
km/s, the masses of four rich clusters are calculated. These clusters
(Triangulum-Australis, Ara, CIZA J1514.6-4558 and CIZA J1410.4-4246) may
contribute to a continued large-scale flow beyond the GA. The results of these
observations will be incorporated into a subsequent analysis of the GA flow.


title: Long-Term X-Ray and TeV variability of Mrk 501

abstract:
  We present X-ray observations of the blazar Mrk501 obtained with RXTE during
1997, 1998, 1999, 2000, and 2004. The goal of this study is twofold: 1)
characterize the long-term X-ray flux and spectral variability of the source
with a model-independent analysis, and 2) investigate the X-ray and TeV
correlation on long timescales. The spectral and temporal variability
properties appear to be markedly different compared to those of
non-jet-dominated radio-loud and radio-quiet AGN monitored with RXTE. To
investigate the X-ray/TeV correlation on long timescales we compared RXTE data
with HEGRA and Whipple historical light curves. We confirm the presence of a
direct correlation, which appears to be stronger when the source is brighter.
The analysis of individual flares shows that the X-ray\TeV correlated activity
is heterogeneous. However, more sensitive TeV observations are necessary to
confirm these findings, and to put tighter constraints on jet models
(abridged).


title: On Kinematic Substructure in the Sextans Dwarf Spheroidal Galaxy

abstract:
  We present multifiber echelle radial velocity results for 551 stars in the
Sextans dwarf spheroidal galaxy and identify 294 stars as probable Sextans
members. The projected velocity dispersion profile of the binned data remains
flat to a maximum angular radius of $30^{\prime}$. We introduce a nonparametric
technique for estimating the projected velocity dispersion surface, and use
this to search for kinematic substructure. Our data do not confirm previous
reports of a kinematically distinct stellar population at the Sextans center.
Instead we detect a region near the Sextans core radius that is kinematically
colder than the overall Sextans sample with 95% confidence.


title: High resolution OH maser survey in star forming regions

abstract:
  We present results of a high resolution survey of OH masers in Galactic Star
Forming Regions in order to study the maser emission and establish a list of
suitable candidates for higher resolution instruments follow up. We used the
Very Long Baseline Array (VLBA) to observe the 1665, 1667, 1612 and 1720 MHz OH
maser transitions within 41 regions. These are the first high resolution
observations for most of the sources. For all the transitions 30 sites of maser
emission were detected, 4 of the sources have new detections, and approximately
40% of the sources in the sample exhibit highly compact structure. Finally we
consider that the spectrum observed in W75N shows the early stage of a long
period OH maser flare in the 1665 MHz line, the first of its kind.


title:
Redshift and Shear Calibration: Impact on Cosmic Shear Studies and
  Survey Design

abstract:
  The cosmological interpretation of weak lensing by large-scale structures
requires knowledge of the redshift distribution of the source galaxies. Current
lensing surveys are often calibrated using external redshift samples which span
a significantly smaller sky area in comparison to the lensing survey, and are
thus subject to sample variance. Some future lensing surveys are expected to be
calibrated in the same way, in particular the fainter galaxy populations where
the entire color coverage, and hence photometric redshift estimate, could be
challenging to obtain. Using N-body simulations, we study the impact of this
sample variance on cosmic shear analysis and show that, to first approximation,
it behaves like a shear calibration error 1+/-epsilon. Using the Hubble Deep
Field as a redshift calibration survey could therefore be a problem for current
lensing surveys. We discuss the impact of the redshift distribution sampling
error and a shear calibration error on the design of future lensing surveys,
and find that a lensing survey of area Theta square degrees and limiting
magnitude m_lim}, has a minimum shear and redshift calibration accuracy
requirements given by epsilon = epsilon_0 10^{beta(m_lim-24.5)} / sqrt(Theta/
200). Above that limit, lensing surveys would not reach their full potential.
Using the galaxy number counts from the Hubble Ultra-Deep Field, we find
(epsilon_0,beta)=(0.015,-0.18) and (epsilon_0,beta)=(0.011,-0.23) for ground
and space based surveys respectively. Lensing surveys with no or limited
redshift information and/or poor shear calibration accuracy will loose their
potential to analyse the cosmic shear signal in the sub-degree angular scales,
and therefore complete photometric redshift coverage should be a top priority
for future lensing surveys.


title:
The low-luminosity galaxy population in the NGC 5044 Group (Conference
  proceeding)

abstract:
  Detailed surface photometry for 79 (mostly dwarf) galaxies in the NGC 5044
Group area is analysed, revealing the existence of different morphologies among
objects originally classified as early-type dwarfs. Particularly, a significant
fraction of bright dwarf "ellipticals" show a distinct bulge+disc structure; we
thus re-classify these objects as dwarf lenticulars (dS0). Our finding points
at a possible scenario where these systems are the remnants of "harassed" disc
galaxies. This is emphasized by the discovery of a few objects with hints for
very low-surface brightness spiral-like structure. The colours, structure, and
spatial distribution of the different galaxy types suggest that our
classification may indeed be separating objects with different origins and/or
evolutionary paths.


title: M 33 X-7: ChASeM33 reveals the first eclipsing black hole X-ray binary

abstract:
  The first observations conducted as part of the Chandra ACIS survey of M 33
(ChASeM33) sampled the eclipsing X-ray binary M 33 X-7 over a large part of the
3.45 d orbital period and have resolved eclipse ingress and egress for the
first time. The occurrence of the X-ray eclipse allows us to determine an
improved ephemeris of mid-eclipse and binary period as HJD (2453639.119+-0.005)
+- N x (3.453014+-0.000020) and constrain the eclipse half angle to (26.5+-1.1)
degree. There are indications for a shortening of the orbital period. The X-ray
spectrum is best described by a disk blackbody spectrum typical for black hole
X-ray binaries in the Galaxy. We find a flat power density spectrum and no
significant regular pulsations were found in the frequency range of 10^{-4} to
0.15 Hz. HST WFPC2 images resolve the optical counterpart, which can be
identified as an O6III star with the help of extinction and colour corrections
derived from the X-ray absorption. Based on the optical light curve, the mass
of the compact object in the system most likely exceeds 9 M_sun. This mass, the
shape of the X-ray spectrum and the short term X-ray time variability identify
M 33 X-7 as the first eclipsing black hole high mass X-ray binary.


title:
Spectral Statistics and Local Luminosity Function of a Hard X-ray
  Complete Sample of Brightest AGNs

abstract:
  We have measured the X-ray spectral properties of a complete flux-limited
sample of bright AGNs from HEAO-1 all-sky catalogs to investigate their
statistics and provide greater constraints on the bright-end of the hard X-ray
luminosity function (HXLF) of AGNs and the AGN population synthesis model of
the X-ray background. Spectral studies using data from ASCA, XMM-Newton and/or
Beppo-SAX observations have been made for almost all AGNs in this sample.
  The spectral measurements enable us to construct the neutral absorbing column
density (Log nH) distribution and separate HXLFs for absorbed (Log nH[cm-2]>
21.5) and unabsorbed AGNs in the local universe. Our results show evidence for
a difference in the shapes of HXLFs of absorbed and unabsorbed AGNs in that
absorbed AGN HXLF drops more rapidly at higher luminosities than that of
unabsorbed AGNs, which is similar to that previously reported. In the Lx - nH
plot, we found no AGN in the high-luminosity high-intrinsic absorption regime
(Log Lx[erg/s]> 44.5, Log nH[cm-2]> 21.5) in our sample, where we expect about
5 AGNs if we assume that absorbed and unabsorbed having identical AGN HXLF
shapes. We also find that the observed flux with ASCA or XMM-Newton is smaller
than that with HEAO-1 by a factor of 0.29 on average, which is expected for
re-observation of sources with a factor 2.5 variability amplitude scale.


title:
The internal dynamics of the Local Group dwarf elliptical galaxies
  NGC147, NGC185, and NGC205

abstract:
  We present three-integral dynamical models for the three Local Group dwarf
elliptical galaxies: NGC147, NGC185, and NGC205. It is the first time models
are constructed for the Local Group dEs that allow for the presence of dark
matter at large radii and that are constrained by kinematics out to at least
one half-light radius. The B-band mass-to-light ratios of all three galaxies
are rather similar, (M/L)_B = 3-4. Within the inner two half-light radii, about
40-50% of the mass is in the form of dark matter, so dEs contain about as much
dark matter as bright ellipticals.
  NGC205 and NGC147 have a relatively isotropic velocity dispersion tensor
within the region where the internal dynamics are strongly constrained by the
data. Our estimated inclination for NGC185 is i ~ 50 degrees because in that
case the model has an intrinsic flattening close to the peak of the intrinsic
shape distribution of dEs and it, like the best fitting models for NGC147 and
NGC205, is nearly isotropic. We also show that the dynamical properties of the
bright nucleus of NGC205 are not unlike those of a massive globular cluster.


title: Deep seawater inherent optical properties in the Southern Ionian Sea

abstract:
  The NEMO (NEutrino Mediterranean Observatory) Collaboration has been carrying
out since 1998 an evaluation programme of deep sea sites suitable for the
construction of the future Mediterranean km3 Cerenkov neutrino telescope. We
investigated the seawater optical and oceanographic properties of several deep
sea marine areas close to the Italian Coast. Inherent optical properties (light
absorption and attenuation coefficients) have been measured as a function of
depth using an experimental apparatus equipped with standard oceanographic
probes and the commercial transmissometer AC9 manufactured by WETLabs. This
paper reports on the visible light absorption and attenuation coefficients
measured in deep seawater of a marine region located in the Southern Ionian
Sea, 60-100 km SE of Capo Passero (Sicily). Data show that blue light
absorption coefficient is about 0.015 1/m (corresponding to an absorption
length of 67 m) close to the one of optically pure water and it doe not show
seasonal variation.


title:
Millimetric observation of the SZ effect in the Corona Borealis
  supercluster

abstract:
  We have observed the Corona Borealis Supercluster with the Millimeter and
Infrared Testa grigia Observatory (MITO), located in the Italian Alps, at 143,
214, 272, and 353 GHz. We present a description of the measurements, data
analysis, and results of the observations together with a comparison with
observations performed at 33 GHz with the Very Small Array (VSA) interferometer
situated at the Teide Observatory (Tenerife-Spain). Observations have been made
in the direction of the supercluster towards one Cosmic Microwave Background
(CMB) cold spot previously detected in a VSA temperature map. Observational
strategy and data analysis are described in detail, explaining the procedures
used to disentangle primary and secondary anisotropies in the resulting maps.
  From a first level of data analysis we find evidence in MITO data of primary
anisotropy, however still with room for the presence of secondary anisotropy,
especially when VSA results are included. With a second level of data analysis
using map-making and the maximum entropy method we claim a weak detection of a
faint signal compatible with a SZ effect characterized at most by a
Comptonization parameter $y=(7.8^{+5.3}_{-4.4})\times10^{-6}$ 68% CL. The low
level of confidence in the presence of a SZ signal invite us to study this sky
region with higher sensitivity and angular resolution experiments like the
already planned upgraded versions of VSA and MITO.


title: Are f(R) dark energy models cosmologically viable ?

abstract:
  All $f(R)$ modified gravity theories are conformally identical to models of
quintessence in which matter is coupled to dark energy with a strong coupling.
This coupling induces a cosmological evolution radically different from
standard cosmology. We find that in all $f(R)$ theories that behave as a power
of $R$ at large or small $R$ (which include most of those proposed so far in
the literature) the scale factor during the matter phase grows as $t^{1/2}$
instead of the standard law $t^{2/3}$. This behaviour is grossly inconsistent
with cosmological observations (e.g. WMAP), thereby ruling out these models
even if they pass the supernovae test and can escape the local gravity
constraints.


title:
Direct Dark Matter Detection with Velocity Distribution in the Eddington
  approach

abstract:
  Exotic dark matter together with the vacuum energy (associated with the
cosmological constant) seem to dominate the Universe. Thus its direct detection
is central to particle physics and cosmology. Supersymmetry provides a natural
dark matter candidate, the lightest supersymmetric particle (LSP). One
essential ingredient in obtaining the direct detection rates is the density and
the velocity distribution of the LSP in our vicinity. In the present paper we
study simultaneously density profiles and velocity distributions in the context
of the Eddington approach. In such an approach, unlike the commonly assumed
Maxwell-Boltzmann (M-B) distribution, the upper bound of the velocity arises
naturally from the potential.


title:
Infrared Spectra and Visibilities as Probes of the Outer Atmospheres of
  Red Supergiant Stars

abstract:
  In the light of the recent results of the stellar interferometry, we examine
the nature of the extra molecular layer outside the photosphere of red super-
giant stars, so far studied mostly with the use of the infrared spectra.
Although the visibility data are more direct probes of the spatial structure of
the outer atmosphere, it is essential that they are analyzed in combination
with the spectral data of a wide spectral coverage. In the case of the M2
supergiant mu Cephei, several sets of data, both spectra and visibilities,
strongly suggested the presence of an extra-molecular layer, and its basic
parameters are estimated to be: excitation temperature T_ex = 1600 K, column
densities of CO and H2O N_col = 3.0d+20/cm2, and inner radius R_in = 2.0R*. The
result shows reasonable agreement with the one based on the infrared spectra
alone, and this may be because the infrared spectra already include some
information on the spatial structure of the outer atmosphere. It is important,
however, that the model inferred from the spectra is now fully supported with
the recent visibility data. In the case of the M2 supergiant alpha Orionis, the
infrared spectra and visibilities show a consistent picture in that its
molecular layer is closer to the photosphere (R_in = 1.3R*) with higher gas
temperature (T_ex = 2250 K) and lower gas column density (N_col = 1.0d+20/cm2),
compared with that of mu Cephei. Some controversy on the interpretation of the
mid infrared data of alpha Orionis can be reconciled.


title: Planetary Nebula Velocities in the Disk and Bulge of M31

abstract:
  We present radial velocities for a sample of 723 planetary nebulae (PNe) in
the disk and bulge of M31, measured using the WYFFOS fibre spectrograph on the
William Herschel telescope. Velocities are determined using the [OIII] 5007
Angstrom emission line. Rotation and velocity dispersion are measured to a
radius of 50 arcminutes (11.5 kpc), the first stellar rotation curve and
velocity dispersion profile for M31 to such a radius. Our kinematics are
consistent with rotational support at radii well beyond the bulge effective
radius of 1.4kpc, although our data beyond a radius of 5kpc are limited. We
present tentative evidence for kinematic substructure in the bulge of M31 to be
studied fully in a later work. This paper is part of an ongoing project to
constrain the total mass, mass distribution and velocity anisotropy of the
disk, bulge and halo of M31.


title: Interactions, Mergers and the Fundamental Mass Relations of Galaxies

abstract:
  We present a study of the effects of mergers and interactions on the mass
distribution of galactic systems in hierarchical clustering scenarios using the
disc-bulge structural parameters and their dynamical properties to quantify
them. We focus on the analysis of the Fundamental Mass Plane relation, finding
that secular evolution phases contribute significantly to the determination of
a plane with a slope in agreement to that of the observed luminosity relation.
In these simulations, secular phases are responsible for the formation of
compact stellar bulges with the correct structural parameter combination. We
also test that the relations among these parameters agree with observations.
Taking into account these results, the hierarchical growth of the structure
predicts a bulge formation scenario for typical field spiral galaxies where
secular evolution during dissipate mergers plays a fundamental role.
Conversely, subsequent mergers can help to enlarge the bulges but do not seem
to strongly modify their fundamental mass relations. Systems get to the local
mass relations at different stages of evolution (i.e. different redshifts) so
that their formation histories introduce a natural scatter in the relations.
Our results suggest that the formation mechanisms of the bulge and disc
components, satisfying their corresponding fundamental mass relations, might be
coupled and that secular evolution could be the possible connecting process.


title:
XMM-Newton Discovery of the X-ray Transient XMMU J181227.8-181234 in the
  Galactic Plane

abstract:
  We report the discovery of an X-ray transient, observed in outburst with
XMM-Newton on March 20, 2003, and with position 18h12m27.8s, -18 12 34 (J2000,
approximate positional error 2"). No known source is present at this position
and the source was not detected during published ROSAT or ASCA observations of
that region. However, the source may be associated with 1H1812-182 detected by
HEAO 1, although the error bars on the HEAO 1 position are very large and the
two sources could also be unrelated. Therefore, we name the source XMMU
J181227.8-181234. Initially, the source was not detected using the All-Sky
Monitor (ASM) on-board the Rossi X-ray Timing Explorer, however, reprocessing
of the ASM data shows that the source was in fact detected and it was active
for about 50 days. The X-ray spectrum of this transient is fitted equally well
by an absorbed power-law (with a spectral index of 2.5) or multi-colour disk
blackbody model (with kT ~ 2 keV), where we find that the source is highly
absorbed. We detect an unabsorbed 0.5-10 keV flux in the range (2-5)E-9 ergs
cm^{-2} s^{-1}, which at a distance of 8 kpc corresponds to a 0.5-10 keV
luminosity of (1-4)E37 ergs s^{-1}. No pulsations were detected by timing
analysis. A colour-colour diagram from ASM data of different accreting objects
suggests that the transient is a high-mass X-ray binary, as is also suggested
by the high absorption compared to the average interstellar value in the
direction of the source. However, the power-law spectral index is far more
typical of a low-mass X-ray binary. Thus, we are unable to conclusively
identify the nature of the transient. We also report on three sources first
detected by the ASCA Galactic Plane Survey that are close to this transient.


title: The Limits of Bound Structures in the Accelerating Universe

abstract:
  According to the latest evidence, the Universe is entering an era of
exponential expansion, where gravitationally bound structures will get
disconnected from each other, forming isolated `island universes'. In this
scenario, we present a theoretical criterion to determine the boundaries of
gravitationally bound structures and a physically motivated definition of
superclusters as the largest bound structures in the Universe. We use the
spherical collapse model self-consistently to obtain an analytical condition
for the mean density enclosed by the last bound shell of the structure (2.36
times the critical density in the present Universe, assumed to be flat, with 30
per cent matter and 70 per cent cosmological constant, in agreement with the
previous, numerical result of Chiueh and He). $N$-body simulations extended to
the future show that this criterion, applied at the present cosmological epoch,
defines a sphere that encloses $\approx 99.7$ per cent of the particles that
will remain bound to the structure at least until the scale parameter of the
Universe is 100 times its present value. On the other hand, $(28\pm 13)$ per
cent of the enclosed particles are in fact not bound, so the enclosed mass
overestimates the bound mass, in contrast with the previous, less rigorous
criterion of, e.~g., Busha and collaborators, which gave a more precise mass
estimate. We also verify that the spherical collapse model estimate for the
radial infall velocity of a shell enclosing a given mean density gives an
accurate prediction for the velocity profile of infalling particles, down to
very near the centre of the virialized core.


title:
Relative spectral lag: an new redshift indicator to measure the cosmos
  with gamma-ray bursts

abstract:
  Using 64 ms count data for long gamma-ray bursts ($T_{90}>$2.6s), we analyze
the quantity, relative spectral lag (RSL), which is defined as
$\tau_{31}/FWHM_{(1)}$, where $\tau_{31}$ is the spectral lag between energy
bands 1 and 3, and $FWHM_{(1)}$ denotes full width at half maximum of the pulse
in energy channel 1. To get insights into features of the RSLs, we investigate
in detail all the correlations between them and other parameters with a
sub-sample including nine long bursts. The general cross-correlation technique
is adopted to measure the lags between two different energy bands. We can
derive the below conclusions. Firstly, the distribution of RSLs is normal and
oncentrates on around the value of 0.1. Secondly, the RSLs are weakly
correlated with $FWHM$, asymmetry, peak flux ($F_{p}$), peak energy ($E_{p}$)
and spectral indexes ($\alpha$ and $\beta$), while they are uncorrelated with
$\tau_{31}$, hardness-ratio ($HR_{31}$) and peak time ($t_m$). The final but
important discovery is that redshift ($z$) and peak luminosity ($L_{p}$) are
strongly correlated with the RSLs which can be measured easily and directly. We
find that the RSL is a good redshift and peak luminosity estimator.


title:
Current Advances in the Methodology and Computational Simulation of the
  Formation of Low-Mass Stars

abstract:
  Developing a theory of low-mass star formation ($\sim 0.1$ to 3~M$_{\odot}$)
remains one of the most elusive and important goals of theoretical
astrophysics. The star-formation process is the outcome of the complex dynamics
of interstellar gas involving non-linear interactions of turbulence, gravity,
magnetic field and radiation. The evolution of protostellar condensations, from
the moment they are assembled by turbulent flows to the time they reach stellar
densities, spans an enormous range of scales, resulting in a major
computational challenge for simulations. Since the previous Protostars and
Planets conference, dramatic advances in the development of new numerical
algorithmic techniques have been successfully implemented on large scale
parallel supercomputers. Among such techniques, Adaptive Mesh Refinement and
Smooth Particle Hydrodynamics have provided frameworks to simulate the process
of low-mass star formation with a very large dynamic range. It is now feasible
to explore the turbulent fragmentation of molecular clouds and the
gravitational collapse of cores into stars self-consistently within the same
calculation. The increased sophistication of these powerful methods comes with
substantial caveats associated with the use of the techniques and the
interpretation of the numerical results. In this review, we examine what has
been accomplished in the field and present a critique of both numerical methods
and scientific results. We stress that computational simulations should obey
the available observational constraints and demonstrate numerical convergence.
Failing this, results of numerical simulations do not advance our understanding
of low-mass star formation.


title:
The Correlation of Narrow Line Emission and X-ray Luminosity in Active
  Galactic Nuclei

abstract:
  We combine emission line and X-ray luminosities for 45 sources from the
Chandra Deep Field South (CDF-S), and seven HELLAS sources, to obtain a new
sample of 52 X-ray selected type-II active galactic nuclei (AGNs). Eighteen of
our sources are very luminous with a typical, absorption-corrected 2-10 keV
luminosity of few 10^{44} erg/sec (type-II QSOs). We compare the emission line
properties of the new sources with emission line and X-ray luminosities of
known low redshift, mostly lower luminosity AGNs by using a composite spectrum.
We find that ${\rm L_{[OIII]}}$/${\rm L_{2-10}}$ and ${\rm L_{[OII]}}$/${\rm
L_{2-10}}$ decrease with L(2-10 keV) such that ${\rm L_{[OIII]}}/{\rm L_{2-10}}
\propto {\rm L_{2-10}}^{-0.42}$. The trend was already evident, yet neglected
in past low redshift samples. This lead to erroneous calibration of the
line-to-X-ray luminosity in earlier AGN samples. The analysis of several type-I
samples shows the same trend with a similar slope but a median ${\rm
L_{[OIII]}}$/${\rm L_{2-10}}$ which is larger by a factor of about two compared
with optically selected type-II samples. We interpret this shift as due to
additional reddening in type-II sources and comment in general on the very
large extinction in many type-II objects and the significantly smaller average
reddening of the SDSS type-II AGNs. The decrease of ${\rm L_{[OIII]}}$/${\rm
L_{2-10}}$ with L(2--10 keV) is large enough to suggest that a significant
fraction of high luminosity high redshift type-II AGNs have very weak emission
lines that may have escaped detection in large samples. A related decrease of
EW([OIII]) with optical continuum luminosity is demonstrated by an analysis of
12,000 type-I SDSS AGNs.


title:
4U 1344-60: a bright intermediate Seyfert galaxy at z=0.012 with a
  relativistic Fe Kalpha emission line

abstract:
  We present analysis of the optical and X-ray spectra of the low Galactic
latitude bright (F(2-10) = 3.6 10^{-11} erg/cm2/s) source 4U 1344-60. On the
basis of the optical data we propose to classify 4U 1344-60 as an intermediate
type Seyfert galaxy and we measure a value of z=0.012+/-0.001 for its redshift.
  From the XMM-Newton observation we find that the overall X-ray spectral shape
of 4U 1344-60 is complex and can be described by a power-law continuum (Gamma ~
1.55) obscured by two neutral absorption components (Nh(f) ~ 10^{22} cm^{-2}
and Nh(p) ~ 4 10^{22} cm^{-2}), the latter covering only the ~50% of the
primary X-ray source. The X-ray data therefore lend support to our
classification of 4U 1344-60. It exhibits a broad and skewed Fe Kalpha line at
6.4 keV, which suggests the existence of an accretion disk that is able to
reprocess the primary continuum down to a few gravitational radii. Such a line
represents one of the clearest examples of a relativistic line observed by
XMM-Newton so far. Our analysis has also revealed the marginal presence of two
narrow line-like emission features at ~4.9 and ~5.2 keV.


title:
The star formation history of early-type galaxies as a function of mass
  and environment

abstract:
  Using the third data release of the Sloan Digital Sky Survey (SDSS) we have
rigorously defined a volume limited sample of early-type galaxies in the
redshift range z < 0.1. We have defined the density of the local environment
for each galaxy using a method which takes account of the redshift bias
introduced by survey boundaries if traditional methods are used. At
luminosities greater than our absolute r-band magnitude cutoff of -20.45 the
mean density of environment shows no trend with redshift. We calculate the Lick
indices for the entire sample and correct for aperture effects and velocity
dispersion in a model independent way. Although we find no dependence of
redshift or luminosity with environment we do find that the mean velocity
dispersion, sigma, of early-type galaxies in dense environments tends to be
higher than in low density environments. Taking account of this effect we find
that several indices show small but very significant trends with environment
that are not the result of the correlation between indices and velocity
dispersion. The statistical significance of the data is sufficiently high to
reveal that models accounting only for alpha-enhancement struggle to produce a
consistent picture of age and metallicity of the sample galaxies, whereas a
model that also includes carbon enhancement fares much better. We find that
early-type galaxies in the field are younger than those in environments typical
of clusters but that neither metallicity, alpha-enhancement nor carbon
enhancement are influenced by the environment. The youngest early-type galaxies
in both field and cluster environments are those with the lowest sigma.
However, there is some evidence that the objects with the largest sigma are
slightly younger, especially in denser environments.


title:
XSS J00564+4548 and IGR J00234+6141 -- new cataclysmic variables from
  RXTE and INTEGRAL all sky surveys

abstract:
  We present the results of optical identification of two X-ray sources from
RXTE and INTEGRAL all sky surveys: XSS J00564+4548 and IGR J00234+6141. Using
the optical data from Russian-Turkish 1.5-m Telescope (RTT150) and SWIFT X-ray
observations, we show that these sources most probably are intermediate polars,
i.e. binary systems with accreting white dwarfs with not very strong magnetic
field (<~10 MG). Periodical oscillations of optical emission with periods 480 s
and 570 s were found. We argue that these periods most probably correspond to
the rotating periods of the white dwarfs in these systems. Further optical
observations scheduled at RTT150 will allow to study the parameters of these
systems in more detail.


title: Photometric observations of Supernovae 2000E, 2001B, 2001V, and 2001X

abstract:
  CCD BVRI photometry is presented for two type Ia supernovae 2000E and 2001V,
for SN Ib 2001B and SN II-P 2001X. The parameters of light curves and absolute
magnitudes at maximum light are estimated. It is shown that all four supernovae
are typical for their classes considering the shape of their light curves and
maximum luminosity.


title: Cygnus A: A Long Wavelength Resolution of the Hot Spots

abstract:
  This paper presents observations of Cygnus A at 74 and 327 MHz at angular
resolutions of approximately 10" and 3", respectively. These observations are
among the highest angular resolutions obtained below 1000 MHz for this object.
While the angular resolution at 74 MHz is not sufficient to separate clearly
the hot spots from the lobes, guided by 151 and 327 MHz images, we have
estimated the 74 MHz emission from the hot spots. We confirm that the emission
from both the western and eastern hot spots flattens at low frequencies and
that there is a spectral asymmetry between the two. For the eastern hot spot, a
low-energy cutoff in the electron energy spectrum appears to explain the
flattening, which implies a cutoff Lorentz factor \gamma_min ~ 300, though we
cannot exclude the possibility that there might be a moderate level of
free-free absorption. For the western hot spot, the current observations are
not sufficient to distinguish between a free-free absorped power-law spectrum
and a synchrotron self-absorbed spectrum.


title:
Structure of the hot object in the symbiotic prototype Z And during its
  2000-03 active phase

abstract:
  Aims: To investigate structure of the hot object in the symbiotic prototype Z
And during its major 2000-03 active phase. Methods: Analysis of the far
ultraviolet, optical low- and high-resolution spectroscopy and UBVR photometry.
Reconstruction of the spectral energy distribution (SED) during the outburst.
The Raman scattering process. Results: At the initial stages of the outburst
the hot object was characterized by the two-temperature spectrum (a warm
stellar radiation and a strong nebular emission) with signatures of a
mass-outflow at moderate (100-200 km/s) and very high (1000-2000 km/s)
velocities. The corresponding structure of the hot object consists of an
optically thick, slowly-expanding disk-like material encompassing the accretor
at the orbital plane and a fast optically thin wind over the remainder of the
star. A striking similarity of [FeVII]6087 and Raman 6825 profiles at/after the
dilution of the disk suggested their origin within the interaction zone where
the winds from the binary components collide.