title: Mc Neil's Nebula in Orion: The Outburst History

abstract:
  We present a sequence of I-band images obtained at the Venezuela 1m Schmidt
telescope during the outburst of the nebula recently discovered by J.W. McNeil
in the Orion L1630 molecular cloud. We derive photometry spanning the
pre-outburst state and the brightening itself, a unique record including 14
epochs and spanning a time scale of ~5 years. We constrain the beginning of the
outburst at some time between Oct. 28 and Nov. 15, 2003. The light curve of the
object at the vertex of the nebula, the likely exciting source of the outburst,
reveals that it has brightened ~5 magnitudes in about 4 months. The time scale
for the nebula to develop is consistent with the light travel time, indicating
that we are observing light from the central source scattered by the ambient
cloud into the line of sight. We also show recent FLWO optical spectroscopy of
the exciting source and of the nearby HH 22. The spectrum of the source is
highly reddened; in contrast, the spectrum of HH 22 shows a shock spectrum
superimposed on a continuum, most likely due to reflected light from the
exciting source reaching the HH object through a much less reddened path. The
blue portion of this spectrum is consistent with an early B spectral type,
similar to the early outburst spectrum of the FU Ori variable V1057 Cyg; we
estimate a luminosity of L ~219 Lsun. The eruptive behavior of the McNeil
nebula source, its spectroscopic characteristics and luminosity, suggest we may
be witnessing an FU Ori event on its way to maximum. Further monitoring of this
object will decide whether it qualifies as a member of this rare class of
objects.


title: Galaxy Structures and External Perturbations in Gravitational Lenses

abstract:
  In modeling strong gravitational lens systems, one often adopts simple
models, such as singular isothermal elliptical density plus lowest-order
external perturbation. However, such simple models may mislead us if the real
mass distribution is more complicated than that in the assumed models. In
particular, assumptions on mass models are crucial in studying flux ratio
anomalies that have been suggested as evidence for a cold dark-matter
substructure. We reinvestigated four quadruple lens systems using power-law
Fourier models, which have advantages of clear physical meanings and the
applicability of a linear method, as well as a simple singular isothermal
elliptical density model. We also investigated the effect of external
perturbations, including a singular isothermal sphere, lowest-order expansion,
and next-order expansion. We have found that the $\cos3\theta$ terms of the
primary galaxy and/or of external perturbation significantly reduce the \chi^2
in PG 1115+080 and B1422+231. In particular, we could reproduce the flux ratios
of B1422+231 with next-order external perturbation assuming 5% flux
uncertainties, suggesting that external perturbation cannot be described by a
simple singular isothermal sphere approximation. On the other hand, we could
not fit B0712+472 and B2045+265 very well even with our models, although the
\chi^2 were reduced compared with the case of using simple models. Our results
clearly demonstrate that both the primary lens galaxy and the external
perturbation are often more complicated than we usually assume.


title: Rotation and accretion of very low mass objects in the SigmaOri cluster

abstract:
  We report on two photometric monitoring campaigns of Very Low Mass (VLM)
objects in the young open cluster around SigmaOrionis. Our targets were
pre-selected with multi-filter photometry in a field of 0.36 sqdeg. For 23 of
these objects, spanning a mass range from 0.03 to 0.7 MS, we detect periodic
variability. Of these, 16 exhibit low-level variability, with amplitudes of
less than 0.2 mag in the I-band, which is mostly well-approximated by a sine
wave. These periodicities are probably caused by photospheric spots co-rotating
with the objects. In contrast, the remaining variable targets show high-level
variability with amplitudes ranging from 0.25 to 1.1 mag, consisting of a
periodic light variation onto which short-term fluctuations are superimposed.
This variability pattern is very similar to the photometric behaviour of
solar-mass, classical T Tauri stars. Low-resolution spectra of a few of these
objects reveal strong Halpha and Ca-triplet emission, indicative of ongoing
accretion processes. This suggests that 5-7% of our targets still possess a
circumstellar disk. In combination with previous results for younger objects,
this translates into a disk lifetime of 3-4 Myr, significantly shorter than for
solar mass stars. The highly variable objects rotate on average slower than the
low-amplitude variables, which is expected in terms of a disk-locking scenario.
There is a trend towards faster rotation with decreasing mass, which might be
caused by shortening of the disk lifetimes or attenuation of magnetic fields.


title:
Stellar Feedback Processes: Their Impact on Star Formation and Galactic
  Evolution

abstract:
  The conditions that lead to self-regulated star formation, star bursts and
the formation of massive stellar clusters are discussed. Massive stars have a
strong impact on their environment, especially on the evolution of dwarf
galaxies which are the building blocks of giant galaxies. Energy input by
massive young clusters might help to solve some of the most important puzzles
of galaxy formation: the cosmological substructure problem and the angular
momentum problem.


title: Classical T Tauri stars as sources of parsec-scale optical outflows

abstract:
  Previous studies of young stellar objects (YSOs) have uncovered a number of
associated parsec-scale optical outflows, the majority of which are driven by
low-mass, embedded Class I sources. Here we examine more evolved Classical T
Tauri stars (CTTSs), i.e. Class II sources, to determine whether these are also
capable of driving parsec-scale outflows. Five such sources are presented here
- CW Tau, DG Tau, DO Tau, HV Tau C and RW Aur, all of which show optical
evidence for outflows of the order of 1pc (24' at the distance of
Taurus-Auriga). These sources were previously known only to drive "micro-jets"
or small-scale outflows < 1' in length. A parsec-scale outflow from a less
evolved source (DG Tau B) which was noted in the course of this work is also
included here. Examination of the five newly discovered large-scale outflows
from CTTSs shows that they have comparable morphologies, apparent dynamical
timescales and degrees of collimation to those from less evolved sources. There
is also strong evidence that these outflows have blown out of their parent
molecular clouds. Finally we note that the "fossil record" provided by these
outflows suggests their sources could have undergone FU Orionis-type outbursts
in the past.


title: INTEGRAL observations of the Large Magellanic Cloud region

abstract:
  We present the preliminary results of the INTEGRAL survey of the Large
Magellanic Cloud. The observations have been carried out in January 2003 (about
10^6 s) and January 2004 (about 4x10^5 s). Here we concentrate on the bright
sources LMC X-1, LMC X-2, LMC X-3 located in our satellite galaxy, and on the
serendipitous detections of the Galactic Low Mass X-ray Binary EXO 0748-676 and
of the Seyfert 2 galaxy IRAS 04575-7537.


title: First results on the HMXRB Pulsar SAXJ2103.5+4545 with INTEGRAL

abstract:
  We report on the preliminary timing and spectral analysis of the High Mass
X-ray Binary Pulsar SAXJ2103.5+4545 as observed with INTEGRAL during the
Galactic Pla n Scan of the Core Program. The source shows a hard spectrum,
being detected up to 100 keV. The timing analysis performed on IBIS/ISGRI data
shows evidence for a spin-up wi th respect to previous observations, performed
in 1997 and 1999 with BeppoSAX an d RossiXTE.


title: The INTEGRAL Burst Alert System: Results and Future Perspectives

abstract:
  The INTEGRAL Burst Alert System (IBAS) is the software for real time
detection of Gamma Ray Bursts (GRBs) and the rapid distribution of their
coordinates. IBAS has been running almost continuously at the INTEGRAL Science
Data Center since the beginning of the INTEGRAL mission, yielding up to now
accurate localizations for 12 GRBs detected in the IBIS field of view. IBAS is
able to provide error regions with radius as small as 3 arcminutes (90% c.l.)
within a few tens of seconds of the GRB start. We present the current status of
IBAS, review the results obtained for the GRBs localized so far, and briefly
discuss future prospects for using the IBAS real time information on other
classes of variable sources.


title:
Hydrodynamic stability of rotationally supported flows: Linear and
  nonlinear 2D shearing box results

abstract:
  We present here both analytical and numerical results of hydrodynamic
stability investigations of rotationally supported circumstellar flows using
the shearing box formalism. Asymptotic scaling arguments justifying the
shearing box approximation are systematically derived, showing that there exist
two limits which we call small shearing box (SSB) and large shearing box (LSB).
The physical meaning of these two limits and their relationship to model
equations implemented by previous investigators are discussed briefly. Two
dimensional (2D) dynamics of the SSB are explored and shown to contain
transiently growing (TG) linear modes, whose nature is first discussed within
the context of linear theory. The fully nonlinear regime in 2D is investigated
numerically for very high Reynolds (Re) numbers. Solutions exhibiting sustained
dynamics are found and manifest episodic but recurrent TG behavior and these
are associated with the formation and long-term survival of coherent vortices.
The life-time of this spatio-temporal complexity depends on the Re number and
the strength and nature of the initial disturbance. We show results for a case
in which the dynamical activity persists for the entire duration of the
simulation (hundreds of box orbits). Some combinations of the Re number and the
initial perturbation spectrum (and strength) show the transiently growing
phenomenon to ultimately fade away or, in some instances, to be absent
altogether. Because the SSB approximation used here is equivalent to a 2D
incompressible flow, the dynamics can not depend on the Coriolis force.
Therefore, three dimensional (3D) simulations are needed in order to decide if
this force indeed suppresses nonlinear hydrodynamical instability in
rotationally supported disks in the shearing box.


title: Inflationary spectra, decoherence, and two-mode coherent states

abstract:
  We re-examine the question of the entropy stored in the distribution of
primordial density fluctuations. To this end we make use of two-mode coherent
states. These states incorporate the isotropy of the distribution as well as
the temporal coherence and the semi-classical character of highly amplified
modes. They also provide a lower bound for the entropy if, as one expects,
decoherence processes erase the squeezing which originally characterized the
distribution in inflationary models. This lower bound is one half the maximal
(thermal) value. By considering backreaction effects, we also provide an upper
bound for this entropy at the onset of the adiabatic era.


title: The Inflationary Paradigm: Predictions for CMB

abstract:
  We review why the search for a causal explanation of the large scale
properties of the universe supports the idea that an extended period of
accelerated expansion, called inflation, preceded primordial nucleosynthesis.
As a consequence of inflation, all pre-existing classical structures are washed
out, and the primordial density fluctuations (the seeds of the large scale
structures) result from the amplification of vacuum quantum fluctuations. The
properties of the spectrum are derived and compared to those of the spectrum of
CMB anisotropies. The agreement is striking.


title: Simulating Galaxies and Galaxy Clusters

abstract:
  The X-ray luminosities of the hot halo gas around simulated, Milky Way like
disk galaxies have been determined, as a function of redshift. The X-ray
luminosity increases significantly with redshift, in some cases as much as a
factor 30 going from z=0 to 2. Consequently, the optimal detection redshift can
be >~0.5.
  Results of fully cosmological simulations of galaxy groups and clusters,
incorporating star formation, chemical evolution with non-instantaneous
recycling, metal-dependent radiative cooling, galactic super-winds and thermal
conduction are presented. X-ray luminosities at z=0 are somewhat high and
central entropies somewhat low compared to observations. This is likely a
combined effect of chemical evolution and metal-dependent, radiative cooling.
Central ICM abundance profiles are somewhat steep, and the observed level of
ICM enrichment can only be reproduced with IMFs more top-heavy than the
Salpeter IMF. In agreement with observations it is found that the iron in the
ICM is in place already at z~1. The [Si/Fe] of the ICM decreases with time, and
increases slightly with radius at a given time. The cluster galaxies match the
observed "red sequence" very well, and the metallicity of cluster galaxies
increases with galaxy mass, as observed.


title: Detection of Polarized Broad Emission in the Seyfert 2 Galaxy Mrk 573

abstract:
  We report the discovery of the scattered emission from a hidden broad-line
region (BLR) in a Seyfert 2 galaxy, Mrk 573, based on our recent
spectropolarimetric observation performed at the Subaru Telescope. This object
has been regarded as a type 2 AGN without a hidden BLR by the previous
observations. However, our high quality spectrum of the polarized flux of Mrk
573 shows prominent broad (~3000 km/s) H_alpha emission, broad weak H_beta
emission, and subtle Fe II multiplet emission. Our new detection of these
indications for the presence of the hidden BLR in the nucleus of Mrk 573 is
thought to be owing to the high signal-to-noise ratio of our data, but the
possibility of a time variation of the scattered BLR emission is also
mentioned. Some diagnostic quantities such as the IRAS color, the radio power,
and the line ratio of the emission from the narrow-line region of Mrk 573 are
consistent with the distributions of such quantities of type 2 AGNs with a
hidden BLR. Mrk 573 is thought to be an object whose level of the AGN activity
is the weakest among the type 2 AGNs with a hidden BLR. In terms of the
systematic differences between the type 2 AGNs with and without a hidden BLR,
we briefly comment on an interesting Seyfert 2 galaxy, Mrk 266SW, which may
possess a hidden BLR but has been treated as a type 2 AGNs without a hidden
BLR.


title: The Diffuse Light in Simulations of Galaxy Clusters

abstract:
  We study the properties of the diffuse light in galaxy clusters forming in a
large hydrodynamical cosmological simulation of the Lambda-CDM cosmology. The
simulation includes a model for radiative cooling, star formation in dense cold
gas, and feedback by SN-II explosions. We select clusters having mass M>10^(14)
h^(-1) Msun and study the spatial distribution of their star particles. While
most stellar light is concentrated in gravitationally bound galaxies orbiting
in the cluster potential, we find evidence for a substantial diffuse component,
which may account for the extended halos of light observed around central cD
galaxies. We find that more massive simulated clusters have a larger fraction
of stars in the diffuse light than the less massive ones. The intracluster
light is more centrally concentrated than the galaxy light, and the stars in
the diffuse component are on average older than the stars in cluster galaxies,
supporting the view that the diffuse light is not a random sampling of the
stellar population in the cluster galaxies. We thus expect that at least ~10%
of the stars in a cluster may be distributed as intracluster light, largely
hidden thus far due to its very low surface brightness.


title: Molecular gas in the galaxy M83. II - Kinematics of the molecular gas

abstract:
  We present the kinematics of the molecular gas in the barred spiral galaxy
M83 (NGC5236). The study is based on ^{12}CO(J=1--0 and 2--1) observations with
the Swedish-ESO Submillimetre Telescope (SEST). Iso-velocity maps of the entire
optical disk, 10'x10' or 13x13 kpc, are produced. They show the pattern of an
inclined, rotating disk, but also the effects of streaming motions along the
spiral arms. A dynamical mass of about 6x10^10 M_sun is estimated by fitting
the rotation curve of an exponential disk model to these data. The gas
constitutes about 13% of the disk mass. The pattern speed is determined from
the residual velocity pattern The locations of various resonances are
discussed. The molecular gas velocity dispersion is determined, and a trend of
decreasing dispersion with increasing galactocentric radius is found. A total
gas (H_2+HI+He) mass surface density map is presented, and compared to the
critical density for star formation of an isothermal gaseous disk. The critical
density is exceeded in the spiral arms, but not in the interarm regions. The
locations of Giant Molecular Associations (GMAs) and HII regions are consistent
with this scenario of dynamically induced star formation.


title:
Search for gamma-ray line emission from the radioactive decay of 60Fe
  with SPI

abstract:
  The search for gamma-ray line emission from the radioactive decay of 60Fe
figures among the prime scientific objectives of the INTEGRAL mission. 60Fe is
believed to be primarily produced in core-collapse supernovae, although other
sites, such as carbon deflagration supernovae or intermediate mass AGB stars
have also been suggested. We present first results of our search for the 1173
and 1332 keV gamma-ray lines of 60Fe decay in the SPI data of the first mission
year. So far we can only report upper flux limits whose levels are determined
by systematic uncertainties in the treatment of the instrumental background.
Once we understand the background uncertainties better, the SPI data should
provide stringent constraints on 60Fe nucleosynthesis in our Galaxy.


title:
Low mass stars, brown dwarf candidates and the mass function of the
  young open cluster NGC 2547

abstract:
  We present a catalogue of RIZ photometry over an area of 0.855 square
degrees, centred on NGC 2547. The survey is substantially complete to limits of
R_c=21.5, I_c=19.5, Z=19.5. We use the catalogue to define NGC 2547 candidates
with masses of about 0.05-1.0 M_sun. After correcting for incompleteness and
contamination by foreground field dwarfs, we investigate the mass function of
the cluster, its binary content, and search for evidence of mass segregation
among lower mass stars. There is evidence for mass segregation between high (>3
M_sun) and lower mass stars, but over the range 0.1<M<0.7 M_sun, the data are
consistent with no further mass segregation. By fitting King profiles we
conclude that at least 60 percent of the low-mass stellar population are
contained in our survey. The cluster mass function is remarkably similar to the
Pleiades for 0.075<M<0.7 M_sun. Because of its age (~30 Myr), we demonstrate
that this mass function is robust to several systematic uncertainties likely to
affect older and younger clusters and is therefore one of the best available
estimates for the initial mass function in young disc populations. For
0.05<M<0.075 M_sun there is some evidence for a deficit of brown dwarfs in NGC
2547 compared with other clusters. This deficit may extend to lower masses or
may only be a dip, perhaps caused by an imperfect understanding of the
mass-magnitude relationship at temperatures of 2800K.Incompleteness in our
survey, and the luminosity functions from which we estimate contamination,
leave this question open. The binary fraction for systems with mass ratios
greater than about 0.5 is 20-35 per cent for M-dwarfs in NGC 2547, quite
consistent with that found in the field (abridged).


title:
Metal enrichment in near-IR luminous galaxies at z~2: signatures of
  proto-ellipticals?

abstract:
  We present the analysis of the coadded rest-frame UV spectrum (1200<z<2000 A)
of five K-luminous galaxies at z~2 from the K20 survey. The composite spectrum
is characterized by strong absorption lines over the UV continuum from C, N, O,
Al, Si, and Fe in various ionization stages. While some of these lines are
interstellar, several among the strongest absorptions are identified with
stellar photospheric lines. Most of the photospheric and interstellar features
are stronger in the K-luminous composite spectrum than in LBGs at z~3. This
suggests higher metallicity and possibly also larger interstellar velocity
dispersion caused by macroscopic motions. The absorption lines and the slope of
the UV continuum is well matched by the spectrum of the nearby luminous
infrared galaxy NGC 6090, which is in the process of merging. A metallicity
higher than solar is suggested by comparing the pure photospheric lines (SiIII,
CIII, FeV) with starburst models. The evidence of high metallicity, together
with the high masses, high star-formation rates, and possibly strong
clustering, well qualify these galaxies as progenitors of local massive
ellipticals.


title:
Multi-wavelength INTEGRAL NEtwork (MINE) observations of the microquasar
  GRS 1915+105

abstract:
  We present the international collaboration MINE (Multi-lambda Integral
NEtwork) aimed at conducting multi-wavelength observations of X-ray binaries
and microquasars simultaneously with the INTEGRAL gamma-ray satellite. We will
focus on the 2003 March-April campaign of observations of the peculiar
microquasar GRS 1915+105 gathering radio, IR and X-ray data. The source was
observed 3 times in the plateau state, before and after a major radio and X-ray
flare. It showed strong steady optically thick radio emission corresponding to
powerful compact jets resolved in the radio images, bright near-infrared
emission, a strong QPO at 2.5 Hz in the X-rays and a power law dominated
spectrum without cutoff in the 3-300 keV range. We compare the different
observations, their multi-wavelength light curves, including JEM-X, ISGRI and
SPI, and the parameters deduced from fitting the spectra obtained with these
instruments on board INTEGRAL.


title:
Transmission- to reflection-dominated transition in Seyfert 2 galaxies:
  the XMM-Newton view

abstract:
  In this paper we present the current status of a XMM-Newton program to
observe an optically-defined, complete and unbiased sample of Compton-thick
Seyfert 2 galaxies. The main goal of this project is the measurement of the
occurrence rate of transition between transmission- (i.e.: Compton-thin), and
reflection-dominated spectral states. These transitions potentially provide
information on the distribution of the obscuring matter surrounding the
nucleus, and on the duty-cycle of the AGN activity. With about 2/3 of the whole
sample being observed, we detected 1 further transition out of 8 observed
objects, confirming previous suggestions that these transitions occur on
time-scales ~50-100 years.


title: Light Thoughts on Dark Energy

abstract:
  The physical process leading to the acceleration of the expansion of the
universe is unknown. It may involve new high energy physics or extensions to
gravitation. Calling this generically dark energy, we examine the consistencies
and relations between these two approaches, showing that an effective equation
of state function w(z) is broadly useful in describing the properties of the
dark energy. A variety of cosmological observations can provide important
information on the dynamics of dark energy and the future looks bright for
constraining dark energy, though both the measurements and the interpretation
will be challenging. We also discuss a more direct relation between the
spacetime geometry and acceleration, via ``geometric dark energy'' from the
Ricci scalar, and superacceleration or phantom energy where the fate of the
universe may be more gentle than the Big Rip.


title: Probing Dark Matter Haloes with Satellite Kinematics

abstract:
  Using detailed mock galaxy redshift surveys we investigate to what extent the
kinematics of large samples of satellites galaxies extracted from flux-limited
surveys can be used to constrain halo masses. Previous host-satellite selection
criteria yield relatively large fractions of interlopers and with a velocity
distribution that, contrary to what has typically been assumed, differs
strongly from uniform. A new adaptive selection criterion is proposed which
yields much larger host-satellite samples and with strongly reduced interloper
fractions. We show that satellite weighting, which occurs naturally when
stacking many host-satellite pairs, introduces a bias towards higher velocity
dispersions compared to the true, host-averaged mean. A further bias, in the
same direction, is introduced when using flux-limited, rather than
volume-limited surveys. We apply our adaptive selection criterion to the 2dFGRS
and obtain a sample of 12613 satellite galaxies and 8004 host galaxies. The
satellite kinematics are in excellent agreement with predictions based on the
conditional luminosity function (CLF), providing independent, dynamical
confirmation of the average mass-to-light ratios predicted by the CLF
formalism.


title:
The SAURON project - III. Integral-field absorption-line kinematics of
  48 elliptical and lenticular galaxies

abstract:
  We present the stellar kinematics of 48 representative elliptical and
lenticular galaxies obtained with our custom-built integral-field spectrograph
SAURON operating on the William Herschel Telescope. The data were homogeneously
processed through a dedicated reduction and analysis pipeline. All resulting
SAURON datacubes were spatially binned to a constant minimum signal-to-noise.
We have measured the stellar kinematics with an optimized (penalized
pixel-fitting) routine which fits the spectra in pixel space, via the use of
optimal templates, and prevents the presence of emission lines to affect the
measurements. We have thus generated maps of the mean stellar velocity, the
velocity dispersion, and the Gauss-Hermite moments h3 and h4 of the
line-of-sight velocity distributions. The maps extend to approximately one
effective radius. Many objects display kinematic twists, kinematically
decoupled components, central stellar disks, and other peculiarities, the
nature of which will be discussed in future papers of this series.


title:
Discovery and Evolution of an Unusual Luminous Variable Star in NGC 3432
  (Supernova 2000ch)

abstract:
  We present photometric and spectroscopic observations of SN 2000ch, an
unusual and extremely luminous variable star located in the galaxy NGC 3432.
The object was discovered on 2000 May 3.2 during the course of the Lick
Observatory Supernova Search, at an unfiltered magnitude of about 17.4.
Pre-discovery images obtained in 1997, 1998, and 2000 April show the object
with R = 19.2-19.5 mag. Optical spectra obtained beginning on 2000 May 6 show a
smooth, flat continuum and strong, broad hydrogen Balmer emission lines at
wavelengths consistent with the catalogued redshift of NGC 3432, strengthening
the association of the variable with the galaxy. Photometric monitoring reveals
a complex and erratic light curve over a time span of ~10 days. Subsequent
optical spectra over the next ~3 months continued to show strong Balmer
emission lines with a mean full-width at half-maximum intensity ~1550 km/s and
a distinct red asymmetry. A spectrum obtained 9 months after the outburst is
similar to the previous spectra, but the integrated flux in H-alpha is nearly
half that observed during the outburst. The object's photometric behavior,
spectrum, and luminosity suggest that it is a very massive and luminous
variable star and might be related to some luminous blue variable stars such as
eta Carinae and SN 1997bs in NGC 3627. The brightest apparent magnitude implies
an absolute magnitude of approximately -12.7 at the distance of NGC 3432, a
value which is comparable to eta Carinae during its outburst in the
mid-nineteenth century.


title:
UBVI Surface Photometry of the Spiral Galaxy NGC 300 in the Sculptor
  Group

abstract:
  We present UBVI surface photometry for 20.'5 X 20.'5 area of a late-type
spiral galaxy NGC 300. In order to understand the morphological properties and
luminosity distribution characteristics of NGC 300, we have derived isophotal
maps, surface brightness profiles, ellipticity profiles, position angle
profiles, and color profiles. By merging the I-band data of our surface
brightness measurements with those of Boeker et al. (2002) based on Hubble
Space Telescope observations, we have made combined I-band surface brightness
profiles for the region of 0."02 < r < 500" and decomposed the profiles into
three components: a nucleus, a bulge, and an exponential disk.


title: The Hot and Cold Spots in the WMAP Data are Not Hot and Cold Enough

abstract:
  This paper presents a frequentist analysis of the hot and cold spots of the
cosmic microwave background data collected by the Wilkinson Microwave
Anisotropy Probe (WMAP). We compare the WMAP temperature statistics of extrema
(number of extrema, mean excursion, variance, skewness and kurtosis of the
excursion) to Monte-Carlo simulations. We find that, on average, the local
maxima (high temperatures in the anisotropy) are too cold and the local minima
are too warm. In order to quantify this claim we describe a two-sided
statistical hypothesis test which we advocate for other investigations of the
Gaussianity hypothesis. Using this test we reject the isotropic Gaussian
hypothesis at more than 99% confidence in a well-defined way. Our claims are
based only on regions that are outside the most conservative WMAP foreground
mask. We perform our test separately on maxima and minima, and on the north and
south ecliptic and Galactic hemispheres and reject Gaussianity at above 95%
confidence for almost all tests of the mean excursions. The same test also
shows the variance of the maxima and minima to be low in the ecliptic north
(99% confidence), but consistent in the south; this effect is not as pronounced
in the Galactic north and south hemispheres.


title:
The first broad-band persistent X-ray spectrum of the dipping low mass
  X-ray binary EXO 0748-676

abstract:
  We report on the results of a BeppoSAX observation of the dipping LMXRB EXO
0748-676 performed in 2000 November. This is the first simultaneous observation
of this source over the 0.1-100 keV energy range. The persistent spectrum is
complex and shows a soft excess, which requires the inclusion of an ionized
absorber (with a sub-solar abundance of iron). A cutoff power-law is a good fit
to the high energy part of the spectrum, with a photon index of 1.3 and a
cutoff around 50 keV. The 0.1-100 keV luminosity is 8.2E36 erg/s.


title:
XMM-Newton results on the ultracompact Low Mass X-ray Binary 4U~1850-087
  in the Globular Cluster NGC6712

abstract:
  We report on preliminary results from our XMM-Newton observation of the Low
Mass X-ray Binary 4U 1850-087, located in the galactic globular cluster NGC
6712. It is an ultracompact binary system, with an orbital period of 20.6 min.
In previous low-resolution X-ray observations 4U 1850-087 displayed a soft
excess residual around 0.7 keV, possibly indicative of the presence of a high
Ne/O ratio. We discuss here our preliminary analysis of high resolution X-ray
spectra of 4U1850-087, and timing results.


title: ISOCAM survey and dust models of 3CR radio galaxies and quasars

abstract:
  We present a survey of all 3CR sources imaged with ISOCAM onboard the
Infrared Space Observatory (ISO). For the source, we present spatially
integrated mid--infrared (MIR, 5 - 18mic.) fluxes measured from newly
calibrated ISOCAM images. In total, we detected 68 AGN of the 3CR catalogue, at
redshifts z < 2.5. The one with the highest redshift is 4C+72.26 at z = 3.53.
ISOCAM data are combined with other photometric measurements to construct the
spectral energy distribution (SED) from optical to radio wavelengths. In order
to describe dust emission we apply new radiative transfer models. By varying
three parameters, luminosity, effective size and extinction, we obtain a fit to
the SED for our objects. In the MIR the hot dust component is mainly due to
small grains and PAHs. In the models, a type 1 AGN is represented by a compact
dust distribution, the dust is therefore very warm and emission of PAHs is weak
because of photo--destruction. In AGNs of type 2, the dust is relatively colder
but PAH bands are strong.


title:
The counter-streaming instability in dwarf ellipticals with off-center
  nuclei

abstract:
  n many nucleated dwarf elliptical galaxies (dE,N's), the nucleus is offset by
a significant fraction of the scale radius with respect to the center of the
outer isophotes. Using a high-resolution N-body simulation, we demonstrate that
the nucleus can be driven off-center by the m=1 counterstreaming instability,
which is strong in flattened stellar systems with zero rotation. The model
develops a nuclear offset on the order of 30% of the exponential scale length.
We compare our numerical results with the photometry and kinematics of FCC 046,
a Fornax Cluster dE,N with a nucleus offset by 1.2" we find good agreement
between the model and FCC 046. We also discuss mechanisms that may cause
counterrotation in dE,N's and conclude that the destruction of box orbits in an
initially triaxial galaxy is the most promising.


title: Observations of the Brackett decrement in the Class I source HH100 IR

abstract:
  The Brackett decrement in the Class I source HH100 IR has been observed and
analyzed to set constraints on the origin of the IR HI emission in this young
object. We have used both low resolution (R ~ 800) observations of the Brackett
lines from Brg, to Br24, and medium resolution (R~9000) spectra of the Brg,
Br12 and Br13 lines. The dereddened fluxes indicates that the lines remain
moderately thick up to high quantum numbers. Moreover, the profiles of the
three lines observed in medium resolution are all broad and nearly symmetric,
with a trend for the lines at high n-number to be narrower than the Brg, line.
With the assumption that the three lines have different optical depths and
consequently trace zones at different physical depths, we interprete the
observed profiles as evidence that the ionized gas velocity in the HI emitting
region is increasing as we move outwards, as expected in an accelerating wind
more than in an infalling gas. We have modelled the observed line ratios and
velocities with a simplified model for the HI excitation in an expanding
circumstellar gas. Such a comparison indicates that the observations are
consistent with the emission coming from a very compact region of 4-6 solar
radii, where the gas has been already accelerated to velocities of the order of
200 \kms, with an associated mass flow rate of the ionized component of the
order of 10^{-7} solar masses per year. This implies that the observed lines
should originate either from a stellar wind or from the inner part of a disk
wind, providing that the disk inner truncation radius is close to the stellar
surface.


title: Transient Accelerated Expansion and Double Quintessence

abstract:
  We consider Double Quintessence models for which the Dark Energy sector
consists of two coupled scalar fields. We study in particular the possibility
to have a transient acceleration in these models. In both Double Quintessence
models studied here, it is shown that if acceleration occurs, it is necessarily
transient. We consider also the possibility to have transient acceleration in
two one-field models, the Albrecht-Skordis model and the pure exponential.
Using separate conservative constraints (marginalizing over the other
parameters) on the effective equation of state $w_{eff}$, the relative density
of the Dark Energy $\Omega_{Q,0}$ and the present age of the universe, we
construct scenarios with a transient acceleration that has already ended at the
present time, and even with no acceleration at all, but a less conservative
analysis using the CMB data rules out the last possibility. The scenario with a
transient acceleration ended by today, can be implemented for the range of
cosmological parameters $\Omega_{m,0}\gtrsim 0.35$ and $h\lesssim 0.68$.


title:
The HELLAS2XMM survey: VI. X-ray absorption in the 1dfAGN sample through
  a spectral analysis

abstract:
  The spectroscopic analysis of 117 serendipitous sources in the HELLAS2XMM 1df
(1 degree field) survey is described. Of these, 106 sources, of which 86% have
a spectroscopic redshift, are used to evaluate the fraction of X-ray absorbed
(log NH>22) Active Galactic Nuclei (AGN) in the 2--10 keV flux range 0.8-20E-14
erg/cm2/s. This fraction turns out lower than what is predicted by two well
known Cosmic X-Ray Background synthesis models, and the discrepancy is
significant at the 99.999% level. This result consolidates the findings
recently obtained by other authors. In the flux interval explored, the data are
consistent with an intrinsic distribution of the absorbing columns (flat per
decade above logNH>21) independent of luminosity and redshift, together with an
AGN luminosity function evolving purely in luminosity. It is shown that, on the
other hand, extrapolation to lower fluxes fails to reproduce the results
inferred from the Chandra Deep Field North survey. It is found that about 40%
of the high luminosity sources in our sample have best fit logNH>22, and the
surface density of these X-ray obscured QSOs can then be estimated at about 48
per square degree, at the flux limit of ~1E-14} erg/cm2/s of the HELLAS2XMM 1df
survey. As a side issue, 5 or 6 out of 60 sources, that is about 10%,
identified with broad line AGN, turn out to be affected by logNH>22 absorption.


title: Achronal cosmic future

abstract:
  The spherically symmetric accretion of dark and phantom energy onto
Morris-Thorne wormholes is considered. It is obtained that the accretion of
phantom energy leads to a gradual increase of the wormhole throat radius which
eventually overtakes the super-accelerated expansion of the universe and
becomes infinite at a time in the future before the occurrence of the big rip
singularity. After that time, as it continues accreting phantom energy, the
wormhole becomes an Einstein-Rosen bridge whose corresponding mass decreases
rapidly and vanishes at the big rip.


title: INTEGRAL and RXTE observations of broad-line radio galaxy 3C 111

abstract:
  3C 111 is an X-ray bright broad-line radio galaxy which is classified as a
Fanaroff-Riley type II source with a double-lobe/single jet morphology, and
reported superluminal motion. It is a well-known X-ray source, and was observed
by every major X-ray observatory since HEAO-1. In this paper we present the
results of the RXTE and INTEGRAL data analysis and compare them with the
results of the previous observations.


title: The density and masses of obscured Black Holes

abstract:
  Recent Chandra and XMM-Newton surveys have uncovered a large fraction of the
obscured AGN responsible of the hard X-ray background. One of the most
intriguing results of extensive programs of follow-up observations concerns the
optical and near-infrared properties of the hard X-ray sources counterparts.
More specifically, for a significant fraction of hard X-ray obscured sources
the AGN responsible of the high X-ray luminosity remains elusive over a wide
range of wavelengths from soft X-rays to near-infrared. This very observational
result opens the possibility to investigate the host of bright obscured quasars
in some detail. Here we briefly report on some preliminar results obtained for
a small sample of elusive AGN in the HELLAS2XMM survey.


title:
The XMM-Newton/2dF survey IV. The X-ray spectral properties of the hard
  sources

abstract:
  We present an analysis of the X-ray spectral properties of 61 hard X-ray
selected (2-8 keV) sources from the bright ($f_{2-8 keV}>10^{-14}$ \funits)
{\it XMM-Newton}/2dF survey. This comprises of 9 {\it XMM-Newton} pointings in
the North Galactic Pole region ($\sim 1.6 \rm deg^2$) and overlaps with the
SDSS, 2QZ and 2dFGRS surveys. Our sources contribute about 50 per cent of the
2-10 keV X-ray background down to the flux limit of $10^{-14}$ cgs. The
hardness ratio distribution of the sample suggests a deficit of heavily
absorbed sources. A spectral fit to the co-added total source spectrum yields a
steep photon index, $\Gamma=1.83^{+0.04}_{-0.05}$. All but 8 sources have
optical counterparts down to the SDSS photometric limit of $r\approx22.5$.
Spectroscopic identifications exist for 34 sources. The vast majority are
associated with Broad-Line (BL) AGN (24 sources) while only 7 present narrow or
no emission lines. Five sources are probably associated with Galactic stars.
Finally, for another 17 probable AGN we present photometric redshifts. The
combined spectrum of the 24 spectroscopically identified BL AGN is steep
($\Gamma=2.02^{+0.04}_{-0.05}$), while that of the 7 AGN, which do not present
broad lines is flatter with $\Gamma=1.64^{+0.11}_{-0.11}$. The spectrum of the
8 optically unidentified sources is flat with $\Gamma\approx 1.1$. Spectral
fits to the individual BL AGN reveal large absorption (rest-frame column
density $\rm>10^{22} cm^{-2}$) in only two cases.
  The individual spectra of the NL AGN present significant evidence for even a
moderate absorption ($\rm 3\times 10^{21} cm^{-2}$) in only one case.


title:
New nearby stars in the Liverpool-Edinburgh high proper motion survey
  selected by DENIS photometry

abstract:
  We present a systematic search for new neighbourhood stars among the
Liverpool-Edinburgh high proper motion survey which we cross-identified with
the DENIS survey. Their high proper motions ensure that they are not giant
stars. The distances are estimated using DENIS photometry and we found that 100
stars probably lie within 25 parsecs from the Sun. They are mostly M-dwarfs,
and 10 are probably white dwarfs. This is the first distance estimate for 84
stars among them. 10 stars, L 170-14A, DENIS J0146291-533931, DENIS
J0235219-240038, LP 942-107, DENIS J0320518-635148, LTT 1732, DENIS
J0428054-620929, DENIS J2210200-701005, DENIS J2230096-534445, and NLTT 166-3
are estimated to be closer than 15 parsecs. In addition, one star, DENIS
J2343155-241047, could also lie within 15 pc if it belongs to the halo.


title: The complex X-ray spectrum of NGC 4507

abstract:
  XMM-Newton and Chandra/HETG spectra of the Compton-thin (NH 4x10^{23}
cm^{-2}) Seyfert 2 galaxy, NGC 4507, are analyzed and discussed. The main
results are: a) the soft X-ray emission is rich in emission lines; an (at
least) two--zone photoionization region is required to explain the large range
of ionization states. b) The 6.4 keV iron line is likely emitted from
Compton-thick matter, implying the presence of two circumnuclear cold regions,
one Compton-thick (the emitter), one Compton-thin (the cold absorber). c)
Evidence of an Fe xxv absorption line is found in the Chandra/HETG spectrum.
The column density of the ionized absorber is estimated to be a few x10^{22}
cm^{-2}.


title:
A 4 - 6 GHz Spectral Scan and 8 - 10 GHz Observations of the Dark Cloud
  TMC-1

abstract:
  The results of the lowest frequency spectral survey carried out toward a
molecular cloud and sensitive observations at selected frequencies are
presented. The entire Arecibo C-band (4--6 GHz) was observed towards the
cyanopolyyne peak of TMC-1 with an rms sensitivity of about 17--18 mK (about
2--2.5 mJy). In addition, a number of selected frequency ranges within the
C-band and X-band (8--10 GHz) were observed with longer integration times and
rms sensitivities 7--8 mK (about 2 mJy) or higher. In the spectral scan itself,
already--known H2CO and HC5N lines were detected. However, in more sensitive
observations at selected frequencies, lines of C2S, C3S, C4H, C4H2, HC3N and
its 13C substituted isotopic species, HC5N, HC7N, and HC9N were found, about
half of them detected for the first time. The rotational temperatures of the
detected molecules fall in the range 4--9 K. Cyanopolyyne column densities vary
from 5.6x10^{13} cm^{-2} for HC5N to 2.7x10^{12} cm^{-2} for HC9N. Our results
show that for molecular observations at low frequencies (4--10 GHz) to be
useful for studying dark clouds, the sensitivity must be of the order of 5--10
mK or better. To date, observations at around 10 GHz have been more productive
than those at lower frequencies.


title: News from Galactic Black Holes

abstract:
  Present status of the possible black hole microlensing events and the present
understanding of high frequency quasi-periodic oscillations in systems
containing black hole candidates (BHCs) are briefly discussed. The growing
evidence for the presence of the event horizons around some compact objects is
reviewed. Finally, the news from four individual objects (SS 433, GX 339-4, CI
Cam and Cyg X-3) are presented and the updated list of BHCs, containing 49
objects is given.


title: The magnetism of the very quiet Sun

abstract:
  When the polarimetric sensitivity and the angular resolution exceed a
threshold, magnetic fields show up almost everywhere on the solar surface. Here
I revise the observational properties of the weakest polarization signals,
which appear in the InterNetwork (IN) regions. We already have some information
on the magnetic field strengths and inclinations, mass motions, lifetimes,
magnetic fluxes, magnetic energies, etc. Since the IN covers a substantial
faction of the solar surface, it may account for most of the unsigned magnetic
flux and energy existing on the solar surface at any given time. This fact
makes IN fields potentially important to understand the global magnetic
properties of the Sun (e.g., the structure of the quiet solar corona, an issue
briefly addressed here). The spectropolarimeters on board of Solar-B have the
resolution and sensitivity to routinely detect these IN fields.


title:
Discovery of a Dusty Ring in the Coalsack: A Dense Core Caught in the
  Act of Formation?

abstract:
  We present a new infrared extinction study of Globule 2, the most opaque
molecular cloud core in the Coalsack complex. Using deep near-infrared imaging
observations obtained with the ESO NTT we are able to examine the structure of
the globule in significantly greater detail than previously possible. We find
the most prominent structural feature of this globule to be a strong central
ring of dust column density which was not evident in lower resolution studies
of this cloud. This ring represents a region of high density and pressure that
is likely a transient structure. For a spherical cloud geometry the ring would
correspond to a dense inner shell of high pressure that could not be in
dynamical equilibrium with its surroundings since there appear to be no sources
of pressure in the central regions of the cloud that could support the shell
against gravity and prevent its inward implosion. The timescale for the inward
collapse of the ring would be less than 2 x 10^5 years, suggesting that this
globule is in an extremely early stage of evolution, and perhaps caught in the
process of forming a centrally condensed dense core or Bok globule. Outside its
central regions the globule displays a well-behaved density profile whose shape
is very similar to that of a stable Bonnor-Ebert sphere. Using SEST we also
obtained a C18O spectrum toward the center of the cloud. The CO observation
indicates that the globule is a gravitationally bound object. Analysis of the
CO line profile reveals significant non-thermal gas motions likely due to
turbulence. As a whole the globule may be evolving to a global state of
quasi-static dynamical equilibrium in which thermal and turbulent pressure
balance gravity.


title: Neutrino oscillations and supernovae

abstract:
  In a 1996 JRO Fellowship Research Proposal (Los Alamos), the author suggested
that neutrino oscillations may provide a powerful indirect energy transport
mechanism to supernovae explosions. The principal aim of this addendum is to
present the relevant unedited text of Section 1 of that proposal. We then
briefly remind, (a) of an early suggestion of Mazurek on vacuum neutrino
oscillations and their relevance to supernovae explosion, and (b) Wolfenstein's
result on suppression of the effect by matter effects. We conclude that whether
or not neutrino oscillations play a significant role in supernovae explosions
shall depend if there are shells/regions of space in stellar collapse where
matter effects play no essential role. Should such regions exist in actual
astrophysical situations, the final outcome of neutrino oscillations on
supernovae explosions shall depend, in part, on whether or not the LNSD signal
is confirmed. Importantly, the reader is reminded that neutrino oscillations
form a set of flavor-oscillation clocks and these clock suffer gravitational
redshift which can be as large as 20 percent. This effect must be incorporated
fully into any calculation of supernova explosion.


title:
Dust heating by the interstellar radiation field in models of turbulent
  molecular clouds

abstract:
  We have calculated the radiation field, dust grain temperatures, and far
infrared emissivity of numerical models of turbulent molecular clouds. When
compared to a uniform cloud of the same mean optical depth, most of the volume
inside the turbulent cloud is brighter, but most of the mass is darker. There
is little mean attenuation from center to edge, and clumping causes the
radiation field to be somewhat bluer. There is also a large dispersion,
typically by a few orders of magnitude, of all quantities relative to their
means. However, despite the scatter, the 850 micron emission maps are well
correlated with surface density. The fraction of mass as a function of
intensity can be reproduced by a simple hierarchical model of density
structure.


title: Kepler and the Kuiper Belt

abstract:
  The proposed field-of-view of the Kepler mission is at an ecliptic latitude
of ~55 degrees, where the surface density of scattered Kuiper Belt Objects
(KBOs) is a few percent that in the ecliptic plane. The rate of occultations of
Kepler target stars by scattered KBOs with radii r>10km is ~10^-6 to 10^-4 per
star per year, where the uncertainty reflects the current ignorance of the
thickness of the scattered KBO disk and the faint-end slope of their magnitude
distribution. These occultation events will last only ~0.1% of the planned
t_exp=15 minute integration time, and thus will appear as single data points
that deviate by tiny amounts. However, given the target photometric accuracy of
Kepler, these deviations will nevertheless be highly significant, with typical
signal-to-noise ratios of ~10. I estimate that 1-20 of the 10^5 main-sequence
stars in Kepler's field-of-view will exhibit detectable occultations during its
four-year mission. For unresolved events, the signal-to-noise of individual
occultations scales as t_exp^{-1/2}, and the minimum detectable radius could be
decreased by an order of magnitude to ~1 km by searching the individual
3-second readouts for occultations. I propose a number of methods by which
occultation events may be differentiated from systematic effects. Kepler should
measure or significantly constrain the frequency of highly-inclined, ~10
km-sized KBOs.


title: The orbital period distribution of wide binary millisecond pulsars

abstract:
  We present results of a binary population synthesis study on the orbital
period distribution of wide binary millisecond pulsars forming through four
evolutionary channels. In three of the channels, the progenitor of the
millisecond pulsar undergoes a common envelope phase prior to the supernova
explosion which gives birth to the neutron star. In the fourth channel, the
primary avoids the common-envelope phase and forms a neutron star when it
ascends the asymptotic giant branch. The four formation channels yield an
orbital period distribution which typically shows a short-period peak below 10
days, a long-period peak around 100 days, and a cut-off near 200 days. The
agreement with the orbital period distribution of observed binary millisecond
pulsars in the Galactic disk is best when the common-envelope ejection is
efficient, the mass-transfer phase responsible for spinning up the pulsar is
highly non-conservative, and no or moderate supernova kicks are imparted to
neutron stars at birth.


title:
An Optical Survey of the Position Error Contours of Unidentified High
  Energy Gamma-Ray Sources at Galactic Latitude b >|20| degrees

abstract:
  We present the most recent results of an optical survey of the position error
contours ("error boxes") of unidentified high energy gamma-ray sources.


title: Radiative cooling, heating and thermal conduction in M87

abstract:
  The crisis of the standard cooling flow model brought about by Chandra and
XMM-Newton observations of galaxy clusters, has led to the development of
several models which explore different heating processes in order to assess if
they can quench the cooling flow. Among the most appealing mechanisms are
thermal conduction and heating through buoyant gas deposited in the ICM by
AGNs. We combine Virgo/M87 observations of three satellites (Chandra,
XMM-Newton and Beppo-SAX) to inspect the dynamics of the ICM in the center of
the cluster. Using the spectral deprojection technique, we derive the physical
quantities describing the ICM and determine the extra-heating needed to balance
the cooling flow assuming that thermal conduction operates at a fixed fraction
of the Spitzer value. We assume that the extra-heating is due to buoyant gas
and we fit the data using the model developed by Ruszkowski and Begelman
(2002). We derive a scale radius for the model of $\sim 5$ kpc, which is
comparable with the M87 AGN jet extension, and a required luminosity of the AGN
of a $few \times 10^{42}$ erg s$^{-1}$, which is comparable to the observed AGN
luminosity. We discuss a scenario where the buoyant bubbles are filled of
relativistic particles and magnetic field responsible for the radio emission in
M87. The AGN is supposed to be intermittent and to inject populations of
buoyant bubbles through a succession of outbursts. We also study the X-ray cool
component detected in the radio lobes and suggest that it is structured in
blobs which are tied to the radio buoyant bubbles.


title:
Meeting the Cool Neighbors VIII: A preliminary 20-parsec census from the
  NLTT catalogue

abstract:
  Continuing our census of late-type dwarfs in the Solar Neighbourhood, we
present BVRI photometry and optical spectroscopy of 800 mid-type M dwarfs drawn
from the NLTT proper motion catalogue. The targets are taken from both our own
cross-referencing of the NLTT catalogue and the 2MASS Second Incremental
release, and from the revised NLTT compiled by Salim & Gould (2003). All are
identified as nearby-star candidates based on their location in the (m_r,
(m_r-K_S)) diagram. Three hundred stars discussed here have previous
astrometric, photometric or spectroscopic observations. We present new BVRI
photometry for 101 stars, together with low resolution spectroscopy of a
further 400 dwarfs. In total, we find that 241 stars are within 20 parsecs of
the Sun, while a further 70 lie within 1-sigma of our distance limit. Combining
the present results with previous analyses, we have quantitative observations
for 1910 of the 1913 candidates in our NLTT nearby-star samples. Eight hundred
and fifteen of those stars have distance estimates of 20 parsecs or less,
including 312 additions to the local census.
  With our NLTT follow-up observations essentially complete, we have searched
the literature for K and early-type M dwarfs within the sampling volume covered
by the 2MASS Second Release. Comparing the resultant 20-parsec census against
predicted numbers, derived from the 8-parsec luminosity function, shows an
overall deficit of ~20% for stellar systems and ~35% for individual stars.
Almost all are likely to be fainter than M_J=7, and at least half are probably
companions of known nearby stars. Our results suggest that there are relatively
few missing systems at the lowest luminosities, M_J > 8.5. We discuss possible
means of identifying the missing stars.


title: Uncorrelated Estimates of Dark Energy Evolution

abstract:
  Type Ia supernova data have recently become strong enough to enable, for the
first time, constraints on the time variation of the dark energy density and
its equation of state. Most analyses, however, are using simple two or
three-parameter descriptions of the dark energy evolution, since it is well
known that allowing more degrees of freedom introduces serious degeneracies.
Here we present a method to produce uncorrelated and nearly model-independent
band power estimates of the equation of state of dark energy and its density as
a function of redshift. We apply the method to recently compiled supernova
data. Our results are consistent with the cosmological constant scenario, in
agreement with other analyses that use traditional parameterizations, though we
find marginal (2-sigma) evidence for w(z) < -1 at z < 0.2. In addition to easy
interpretation, uncorrelated, localized band powers allow intuitive and
powerful testing of the constancy of either the energy density or equation of
state. While we have used relatively coarse redshift binning suitable for the
current set of about 150 supernovae, this approach should reach its full
potential in the future, when applied to thousands of supernovae found from
ground and space, combined with complementary information from other
cosmological probes.


title: Tiny-Scale Molecular Structures in the Magellanic Clouds (Part 1)

abstract:
  We report on the {\small FUSE} detections of the HD and CO molecules {\bf on
the lines of sight towards three Large Magellanic stars}: Sk $-$67D05, Sk
$-$68D135, and Sk $-$69D246. HD is also detected for the first time {\bf on the
lines of sight towards two Small Magellanic Cloud stars}: AV 95 and Sk 159.
While the HD and CO abundances are expected to be lower in the Large Magellanic
Cloud where molecular fractions are a third of the Galactic value and where the
photodissociation flux is up to thousands times larger, we report an average
HD/H$_2$ ratio of 1.4$\pm$0.5 ppm and CO/H$_2$ ratio ranging from 0.8 to 2.7
ppm similar to the Galactic ones. We tentatively identify a deuterium reservoir
(hereafter D--reservoir) towards the Small Magellanic Cloud, along the light
path to AV 95. We derive a D/H ratio ranging from 1. 10$^{-6}$ to 1.1
10$^{-5}$.


title: Atomic X-Ray Spectra of Accretion Disk Atmospheres in the Kerr Metric

abstract:
  We calculate the atmospheric structure of an accretion disk around a Kerr
black hole and obtain its X-ray spectrum, which exhibits prominent atomic
transitions under certain circumstances. The gravitational and Doppler
(red)shifts of the C V, C VI, O VII, O VIII, and Fe I-XXVI emission lines are
observable in active galaxies. We quantify the line emissivities as a function
of radius, to identify the effects of atmospheric structure, and to determine
the usefulness of these lines for probing the disk energetics. The line
emissivities do not always scale linearly with the incident radiative energy,
as in the case of Fe XXV and Fe XXVI. Our model incorporates photoionization
and thermal balance for the plasma, the hydrostatic approximation perpendicular
to the plane of the disk, and general relativistic tidal forces. We include
radiative recombination rates, fluorescence yields, Compton scattering, and
photoelectric opacities for the most abundant elements.


title: First Evidence of Circumstellar Disks around Blue Straggler Stars

abstract:
  We present an analysis of optical HST/STIS and HST/FOS spectroscopy of 6 blue
stragglers found in the globular clusters M3, NGC6752 and NGC6397. These stars
are a subsample of a set of ~50 blue stragglers and stars above the main
sequence turn-off in four globular clusters which will be presented in an
forthcoming paper. All but the 6 stars presented here can be well fitted with
non-LTE model atmospheres. The 6 misfits, on the other hand, possess Balmer
jumps which are too large for the effective temperatures implied by their
Paschen continua. We find that our data for these stars are consistent with
models only if we account for extra absorption of stellar Balmer photons by an
ionized circumstellar disk. Column densities of HI and CaII are derived as are
the the disks' thicknesses. This is the first time that a circumstellar disk is
detected around blue stragglers. The presence of magnetically-locked disks
attached to the stars has been suggested as a mechanism to lose the large
angular momentum imparted by the collision event at the birth of these stars.
The disks implied by our study might not be massive enough to constitute such
an angular momentum sink, but they could be the leftovers of once larger disks.


title:
The relation between galaxy activity and the dynamics of compact groups
  of galaxies

abstract:
  Using a sample of 91 galaxies distributed over 27 Compact Groups of Galaxies
(CGs), we define an index that allows us to quantify their level of activity,
be it AGN or star formation. By combining the mean activity index with the mean
morphological type of the galaxies in a group we are able to quantify the
evolutionary state of the groups. We find that they span a sequence in
evolution, which is correlated with the spatial configuration of the galaxies
making up a CG. We distinguish three main configuration: Type A CGs show
predominantly low velocity dispersions and are rich in late-type spirals that
are active in terms of star formation or harbor an AGN; Type B groups have
intermediate velocity dispersions and contain a large fraction of interacting
or merging galaxies; Type C is formed by CGs with high velocity dispersions,
which are dominated by elliptical galaxies that show no activity. We suggest
that the level of evolution increases in the sense A-->B-->C. Mapping the
groups with different evolution levels in a diagram of radius versus velocity
dispersion does not reveal the pattern expected based on the conventional fast
merger model for CGs. Instead, we observe a trend that goes contrary to
expectation: the level of evolution of a group increases with velocity
dispersion. This trend seems to be related to the masses of the structures in
which CGs are embedded. In general, the level of evolution of a group increases
with the mass of the structure. This suggests either that galaxies evolve more
rapidly in massive structures or that the formation of CGs embedded in massive
structures predated the formation of CGs associated with lower mass systems.
Our observations are consistent with CDM (or Lambda CDM) structures formation
scenarios, assuming the formation of galaxies is a biased process.


title:
Superposition of blackbodies and the dipole anisotropy: A possibility to
  calibrate CMB experiments

abstract:
  The CMB angular temperature fluctuations observed by COBE and WMAP enable us
to place a lower limit on the spectral distortions of the CMB at any angular
scale. These distortions are connected with the simple fact, that the
superposition of blackbodies with different temperatures in general is not a
blackbody. We show, that in the limit of small temperature fluctuations, the
superposition of blackbodies leads to a y-type spectral distortion. It is
known, that the CMB dipole induces a y-type spectral distortion with quadrupole
and monopole angular distribution leading to a corresponding whole sky
y-parameter of y~2.6\cdot 10^{-7}.We show here that taking the difference of
the CMB signal in the direction of the maximum and minimum of the CMB dipole
due to the superposition of two blackbodies leads to a spectral distortion with
y~3.1\cdot 10^{-6}. The amplitude of this distortion can be calculated to the
same precision as the CMB dipole, i.e. 0.3% today. Therefore it may be used as
a source with brightness of several or tens of \muK to cross calibrate and
calibrate different frequency channels of CMB surveys with precision of a few
tens or hundreds of nK. Furthermore, we show in this work that primordial
anisotropies for multipoles 2\leq l \leq 1000 also lead to spectral distortions
but with much smaller y-parameter, i.e. y\sim 10^{-11}-10^{-9}.


title: A Comprehensive Study of Young Black Hole Populations

abstract:
  We present theoretical models of black hole (BH) populations in young stellar
environments, such as starbursts and young star clusters. Using a population
synthesis approach we compute the formation rates and characteristic properties
of single and binary BHs for various representative ages and choices of
parameters. We find that most of the BHs (typically 80% for an initial 50%
binary fraction) are single, but with many originating from primordial binaries
(which either merged into a single massive star or were disrupted following a
supernova explosion). A smaller but significant fraction (typically 20%) of the
BHs remain in binary systems. Main-sequence stars are the most frequent BH
companions, but massive BH--BH binaries are the next most numerous group. The
most massive BHs found in our simulations reach 80 Msun, and are formed through
mergers of massive binary components. If formed in a dense star cluster such a
massive stellar BH may become the seed for growth to a more massive
(``intermediate-mass'') BH. Although we do not include dynamical interactions,
our results provide realistic initial conditions for N-body simulations of
dense star clusters (e.g., globular clusters) including primordial BHs.


title: SX Phoenicis Stars in the Globular Cluster NGC 5466

abstract:
  Through time-series CCD photometry of the globular cluster NGC 5466, we have
detected nine SX Phoenicis stars including three new ones. All the SX Phoenicis
stars are located in the blue straggler region in the color-magnitude diagram
of NGC 5466. Five of them show clearly double-radial mode features, the periods
of which are well consistent with the theoretical ratio of the first overtone
mode to the fundamental mode (P$_{1H}$/P$_F$). Normally, it has not been easy
to secure a P-L relation of the SX Phoenicis stars, because determination of
the pulsational mode of the SX Phoenicis stars has been difficult. The
existence of five SX Phoenicis stars in NGC5466 with double-radial modes allows
us to derive reliably a P-L relation for the fundamental mode of the SX
Phoenicis stars. Using seven SX Phoenicis stars including five stars with
double-radial modes, we derive a P-L relation for the fundamental mode in NGC
5466, $<V> = - 3.25 (\pm 0.46) Log P + 14.70 (\pm 0.06), (\sigma = \pm0.04) $,
corresponding to $<M_V> = - 3.25 (\pm0.46)Log P - 1.30 (\pm0.06) $ for an
adopted distance modulus of $(m-M)_0=16.00$ and zero reddening.


title: Two programs for studying stellar evolution and nuclear astrophysics

abstract:
  Two FORTRAN programs are presented which plot the Hertzsprung-Russell diagram
and the temporal evolution of such stellar quantities as: central and
photospheric isotopic abundances, central densities and temperatures,
luminosities,effective temperatures and photospheric radii for a wide range of
stellar masses. The programs, which are modifications and extensions of some
modules of the TYCHO 6.0 stellar evolution package, are accompanied by various
control input files as well as by a library of data. The data library is
actually one of the output files generated by TYCHO 7.0 (a modified version of
TYCHO 6.0), while the plots themselves are generated by the PGPLOT Graphics
Subroutine Library which is also publicly available and well cited.


title:
Observational constraints on the cosmological evolution of
  dual-population radio sources

abstract:
  In this paper we show normalized differential source counts n(S) at 408 MHz
and 1.4 GHz of radio sources separately for FRI and FRII classes with extended
and compact morphologies. The maps from the FIRST, NVSS, and WENSS surveys are
used to define the source morphology and flux density. The counts provide a
basis for a direct test as well as constraining the cosmological evolution of
powerful extragalactic radio sources in terms of the dual-population model
(Jackson & Wall 1999), where radio sources of Fanaroff-Riley (1974) types I and
II are regarded as two physically separate types of active galactic nuclei
(AGN). The predicted count values are compared with the observational data to
find the best fits for the evolution and beaming parameters, and to further
refine the model.


title: The substellar population of the young cluster lambda Orionis

abstract:
  By collecting optical and infrared photometry and low resolution
spectroscopy, we have identified a large number of low mass stars and brown
dwarf candidates belonging to the young cluster (~5 Myr) associated with the
binary star lambda Orionis. The lowest mass object found is a M8.5 with an
estimated mass of 0.02 Msun (~0.01 Msun for objects without spectroscopic
confirmation).
  For those objects with spectroscopy, the measured strength of the Halpha
emission line follows a distribution similar to other clusters with the same
age range, with larger equivalent widths for cooler spectral types. Three of
the brown dwarfs have Halpha emission equivalent widths of order 100 \AA,
suggestive that they may have accretion disks and thus are the substellar
equivalent of Classical T Tauri stars. We have derived the Initial Mass
Function for the cluster. For the substellar regime, the index of the mass
spectrum is alpha=0.60$+-0.06, very similar to other young associations.


title: Large-Scale Radio Structure in the Universe: Giant Radio Galaxies

abstract:
  Giant radio galaxies (GRGs), with linear sizes larger than 1 Mpc (H0=50
km/s/Mpc), represent the biggest single objects in the Universe. GRGs are rare
among the entire population of radio galaxies (RGs) and their physical
evolution is not well understood though for many years they have been of
special interest for several reasons. The lobes of radio sources can compress
cold gas clumps and trigger star or even dwarf galaxy formation, they can also
transport gas from a host galaxy to large distances and seed the IGM with
magnetic fields. Since GRGs have about 10 to 100 times larger sizes than normal
RGs, their influence on the ambient medium is correspondingly wider and is
pronounced on scales comparable to those of clusters of galaxies or larger.
Therefore `giants' could play an important role in the process of large-scale
structure formation in the Universe. Recently, thanks to the new all sky radio
surveys, significant progress in searching for new GRGs has been made.


title: Some Current Theoretical Issues around Ultra-High Energy Cosmic Rays

abstract:
  We address some current theoretical issues around ultra-high energy cosmic
rays. We recall that scenarios producing more gamma-rays than cosmic rays up to
high redshift can in general only provide a sub-dominant contribution to the
ultra-high energy cosmic ray flux. This includes extra-galactic top-down and
the Z-burst scenarios. Finally we discuss the influence of large scale cosmic
magnetic fields on ultra-high energy cosmic ray propagation which is currently
hard to quantify. The views presented here represent the authors perspective.


title:
The Detection of Terrestrial Planets via Gravitational Microlensing:
  Space vs. Ground-based Surveys

abstract:
  I compare an aggressive ground-based gravitational microlensing survey for
terrestrial planets to a space-based survey. The Ground-based survey assumes a
global network of very wide field-of-view ~2m telescopes that monitor fields in
the central Galactic bulge. I find that such a space-based survey is ~100 times
more effective at detecting terrestrial planets in Earth-like orbits. The poor
sensitivity of the ground-based surveys to low-mass planets is primarily due to
the fact that the main sequence source stars are unresolved in ground-based
images of the Galactic bulge. This gives rise to systematic photometry errors
that preclude the detection of most of the planetary light curve deviations for
low mass planets.


title:
GeV and higher energy photon interactions in gamma-ray burst fireballs
  and surroundings

abstract:
  We have calculated the opacities and secondary production mechanisms of high
energy photons arising in gamma-ray burst internal shocks, using exact
cross-sections for the relevant processes. We find that for reasonable choices
of parameters, photons in the range of 10's to 100's of GeV may be emitted in
the prompt phase. Photons above this range are subject to electron-positron
pair production with fireball photons and would be absent from the spectrum
escaping the gamma-ray burst. We find that, in such cases, the fireball becomes
optically thin again at ultra-high energies ($\gtrsim$ PeV). On the other hand,
for sufficiently large fireball bulk Lorentz factors, the fireball is optically
thin at all energies. Both for $\gamma\gamma$ self-absorbed and optically thin
cases, the escaping high energy photons can interact with infra-red and
microwave background photons to produce delayed secondary photons in the
GeV-TeV range. These may be observable with GLAST, or at low redshifts with
ground-based air Cherenkov telescopes. Detection of the primary prompt spectrum
constrains the bulk Lorentz factor, while detection of delayed secondary
gamma-rays would provide a consistency check for the primary spectrum and the
bulk Lorentz factor as well as constraints on the intergalactic magnetic field
strength.


title:
R=100,000 Spectroscopy of Photodissociation Regions: H2 Rotational Lines
  in the Orion Bar

abstract:
  Ground state rotational lines of H2 are good temperature probes of moderately
hot (200-1000 K) gas. The low A-values of these lines result in low critical
densities while ensuring that the lines are optically thin. ISO observations of
H2 rotational lines in PDRs reveal large quantities of warm gas that are
difficult to explain via current models, but the spatial resolution of ISO does
not resolve the temperature structure of the warm gas. We present and discuss
high spatial resolution observations of H2 rotational line emission from the
Orion Bar.


title:
XMM-Newton observations of the sigma Ori cluster. I. The complex RGS
  spectrum of the hot star sigma Ori AB

abstract:
  We present XMM-Newton observations of the young (~2-5 Myr) cluster around the
hot (O9.5V) star sigma Orionis AB, aimed at obtaining a high resolution RGS
spectrum of the hot star as well as EPIC imaging data for the whole field. We
show that the RGS spectrum of sigma Ori AB may be contaminated by weaker nearby
sources which required the development of a suitable procedure to extract a
clean RGS spectrum and to determine the thermal structure and wind properties
of the hot star. We also report on the detection of a flare from the B2Vp star
sigma Ori E and we discuss whether the flare originated from the hot star
itself or rather from an unseen late-type companion. Other results of this
observation include: the detection of 174 X-ray sources in the field of sigma
Ori of which 75 identified as cluster members, including very low-mass stars
down to the substellar limit; the discovery of rotational modulation in a
late-type star near sigma Ori AB; no detectable line broadenings and shifts
(<800 km s^-1) in the spectrum of sigma Ori AB together with a remarkable low
value of the O VII forbidden to intercombination line ratio and unusually high
coronal abundances of CNO elements.


title: Cooling delay for protoquark stars due to neutrino trapping

abstract:
  The influence of neutrino trapping (NT) on the early cooling evolution of hot
proto quark stars (PQS) with initial temperatures in the range T ~ 40 MeV is
studied. Within a simplified model for the neutrino transport it is shown that
the time for reaching neutrino opacity temperature of T_{opac} ~ 1 MeV is about
10 sec. This is an order of magnitude larger than without NT and of the same
order as the duration long gamma ray bursts.


title:
From Reference Frames to Relativistic Experiments: Absolute and Relative
  Radio Astrometry

abstract:
  Reference systems and frames are crucial for high precision absolute
astrometric work, and their foundations must be well-defined. The current
frame, the International Celestial Reference Frame, will be discussed: its
history, the use of the group delay as the measured quantity, the positional
accuracy of 0.3 milliarcsec, and possible future improvements. On the other
hand, for the determination of the motion of celestial objects, accuracies
approaching 0.01 milliarcsec can be obtained by measuring the differential
position between the target object and nearby stationary sources. This
astrometric technique uses phase referencing, and the current techniques and
limitations are discussed, using the results from four experiments. Brief
comments are included on the interpretation of the Jupiter gravity deflection
experiment of September 2002.


title: Study of changes in the Solar Environment

abstract:
  Recent studies have shown that the local environment of the Sun is a complex
one with the presence of several supernova shock bubbles and interstellar
clouds. Even within this environment, the Sun is moving with a velocity of
about 15 km/s toward the interior of the galaxy. We examine the changes in the
local ISM environment experienced by the Sun in the past and then discuss the
interaction of the Sun with these different environments. Lastly, we inquire
how this must have changed the cosmic ray environment of the earth since this
remains one of the few methods to test the changes in the local ISM environment
over astronomical time scales. %


title: Rapid Oscillations in Cataclysmic Variables. XVI. DW Cancri

abstract:
  We report photometry and spectroscopy of the novalike variable DW Cancri. The
spectra show the usual broad H and He emission lines, with an excitation and
continuum slope characteristic of a moderately high accretion rate. A
radial-velocity search yields strong detections at two periods, 86.1015(3) min
and 38.58377(6) min. We interpret these as respectively the orbital period
P_orb of the binary, and the spin period P_spin of a magnetic white dwarf. The
light curve also shows the spin period, plus an additional strong signal at
69.9133(10) min, which coincides with the difference frequency
1/P_spin-1/P_orb. These periods are stable over the 1 year baseline of
measurement.
  This triply-periodic structure mimics the behavior of several
well-credentialed members of the "DQ Herculis" (intermediate polar) class of
cataclysmic variables. DQ Her membership is also suggested by the mysteriously
strong sideband signal (at nu_spin-nu_orb), attesting to a strong pulsed flux
at X-ray/EUV/UV wavelengths. DW Cnc is a new member of this class, and would be
an excellent target for extended observation at these wavelengths.


title:
Forecast for Epoch-of-Reionization as viewable by the PrimevAl Structure
  Telescope (PAST)

abstract:
  We present sensitivity forecasts for the PAST 21cm reionization observations
and compare these with the measured sensitivity of a prototype array. We
discuss the likely epoch-of-reionization structures and the redshifts that can
be observed, and conclude that a 10,000 antenna PAST will be able to image
ionized structures with its 1 million pixel map at 6<z<20. The angular scales
of the images to be produced span from 5 arc minutes to 10 degrees. The effect
of potential foreground contaminants are analyzed. All known extra-terrestial
foregrounds have power law continuum spectra, and can be modeled and cleanly
separated. We present results of observations using the prototype, which verify
the estimated sensitivities and provide data on astronomical foregrounds. The
same sample allows real-world measurement of man-made interference, of meteor
scatter propagation, and of ionospheric variation. These data are also used to
verify our large angle map making algorithms.


title: Observing the build-up of the colour-magnitude relation at redshift ~0.8

abstract:
  We analyse the rest-frame (U-V) colour-magnitude relation for 2 clusters at
redshift 0.7 and 0.8, drawn from the ESO Distant Cluster Survey. By comparing
with the population of red galaxies in the Coma cluster, we show that the high
redshift clusters exhibit a deficit of passive faint red galaxies. Our results
show that the red-sequence population cannot be explained in terms of a
monolithic and synchronous formation scenario. A large fraction of faint
passive galaxies in clusters today has moved onto the red sequence relatively
recently as a consequence of the fact that their star formation activity has
come to an end at z<0.8.


title: The angular power spectrum of NVSS radio galaxies

abstract:
  We measure the angular power spectrum of radio galaxies in the NRAO VLA Sky
Survey (NVSS) using two independent methods: direct spherical harmonic analysis
and maximum likelihood estimation. The results are consistent and can be
understood using models for the spatial matter power spectrum and for the
redshift distribution of radio galaxies at mJy flux-density levels. A good fit
to the angular power spectrum can only be achieved if radio galaxies possess
high bias with respect to mass fluctuations; by marginalizing over the other
parameters of the model we derive a 68% confidence interval 1.53 < b_0 sigma_8
< 1.87, where b_0 is the linear bias factor for radio galaxies and sigma_8
describes the normalization of the matter power spectrum. Our models indicate
that the majority of the signal in the NVSS angular power spectrum is generated
at low redshifts. Individual redshifts for the NVSS sources are thus required
to alleviate projection effects and probe directly the matter power spectrum on
large scales.


title: Exact solutions for the interacting tachyonic-dark matter system

abstract:
  We find exact solutions leading to power law accelerated expansion for a
homogeneous, isotropic and spatially flat universe, dominated by an interacting
mixture of cold dark matter and a tachyonic field such that the ratio of the
energy densities of both components at late times is constant and no
coincidence problem arises.


title: X-ray number counts of star forming galaxies

abstract:
  The behaviour of the X-ray number counts of normal galaxies at faint (-18<Log
F<-15 cgs in the 0.5-2.0 keV band) fluxes is investigated. The joint use of
information from radio, far infrared and X-ray surveys allows the determination
of the LogN-LogS of galaxies within a factor-of-3 over the whole flux range
considered.


title:
FUSE search for 10^5-10^6 K gas in the rich clusters of galaxies Abell
  2029 and Abell 3112

abstract:
  Recent Chandra and XMM X-ray observations of rich clusters of galaxies have
shown that the amount of hot gas which is cooling below ~1 keV is generally
more modest than previous estimates. Yet, the real level of the cooling flows,
if any, remains to be clarified by making observations sensitive to different
temperature ranges. As a follow-up of the FUSE observations reporting a
positive detection of the OVI doublet at 1032, 1038 Angstrom in the cluster of
galaxies Abell 2597, which provided the first direct evidence for ~3x10^5 K gas
in a cluster of galaxies, we have carried out sensitive spectroscopy of two
rich clusters, Abell 2029 and Abell 3112 (z~0.07) located behind low HI
columns. In neither of these clusters could we detect the OVI doublet, yielding
fairly stringent limits of ~27 Msun yr-1 (Abell 2029) and ~25 Msun yr-1 (Abell
3112) to the cooling flow rates using the 10^5-10^6 K gas as a tracer. The
non-detections support the emerging picture that the cooling-flow rates are
much more modest than deduced from earlier X-ray observations.


title:
Stellar dynamics of blue compact galaxies: I. Decoupled star-gas
  kinematics in ESO 400-G43

abstract:
  In this letter we present the first results from a program aimed at measuring
the stellar kinematics of blue compact galaxies by observing the near-infrared
Calcium triplet. We show the first results for ESO 400-G43 based on deep
VLT/FORS2 spectroscopy. The instabilities found in the central gaseous velocity
field are not seen in the solid body stellar rotation curve, indicating that
stars and gas are kinematically decoupled in this galaxy. Even if this galaxy
has a perturbed gaseous velocity field, the stellar velocity dispersion on
average agrees well with that derived from the nebular lines.


title: The IceCube Project

abstract:
  This talk gives a brief description of goals, expected performance and status
of the Icecube project.


title: Accretion stream mapping with genetically modified "fire-flies"

abstract:
  We apply an eclipse mapping technique using `genetically modified fire-flies'
to the eclipse light curves of HU Aqr and EP Dra. The technique makes as few
assumptions as possible about the location of accretion stream material,
allowing the emission to be located anywhere within the Roche lobe of the white
dwarf. We model two consecutive eclipses in the UBVR_c band for HU Aqr, and
four consecutive `white'-light eclipses for EP Dra, to determine the changing
brightness distribution of stream material. We find fire-fly distributions
which are consistent with accretion through a curtain of material in both HU
Aqr and EP Dra, and show that the previously assumed two part ballistic and
magnetic trajectory is a good approximation for polars. Model fits to the
colour band data of HU Aqr indicate that the material confined to the magnetic
field lines is brightest, and most of the emission originates from close to the
white dwarf. There is evidence for emission from close to a calculated
ballistic stream in both HU Aqr and EP Dra.We propose that a change in the
stream density causes a change in the location of the bright material in the
accretion stream in EP Dra.


title:
Ellipticity and Deviations from Orthogonality in the Polarization Modes
  of PSR B0329+54

abstract:
  We report on an analysis of the polarization of single pulses of PSR B0329+54
at 328 MHz. We find that the distribution of polarization orientations in the
central component diverges strongly from the standard picture of orthogonal
polarization modes (OPMs), making a remarkable partial annulus on the Poincare
sphere. A second, tightly clustered region of density appears in the opposite
hemisphere, at a point antipodal to the centre of the annulus. We argue that
this can be understood in terms of birefringent alterations in the relative
phase of two elliptically polarized propagation modes in the pulsar
magnetosphere (i.e. generalised Faraday rotation). The ellipticity of the modes
implies a significant charge density in the plasma, while the presence of both
senses of circular polarization, and the fact that only one mode shows the
effect, supports the view that refracted ordinary-mode rays are involved in the
production of the annulus. At other pulse longitudes the polarization
(including the circular component) is broadly consistent with an origin in
elliptical OPMs, shown here quantitatively for the first time, however
considerable non-orthogonal contributions serve to broaden the orientation
distribution in an isotropic manner.


title:
A systematic search for massive young stars in the Galaxy - the RMS
  survey

abstract:
  We have selected red MSX sources (RMS) that have the colours of massive young
stellar objects (MYSOs). Our aim is to generate a large, systematically
selected sample to address questions such as their luminosity function,
lifetimes, clustering and triggering. Other objects such as UCHIIs, PN, PPN and
AGB stars have similar IR colours and a large programme of ground-based
follow-up observations is underway to identify and eliminate these from the
sample of the red MSX sources. These include radio continuum observations,
kinematic distances, ground-based mid-IR imaging, near-IR imaging and
spectroscopy to distinguish. We report the progress of these campaigns on the
3000 candidates, with initial indications showing that a substantial fraction
are indeed massive YSOs.


title:
The vertical structure of T Tauri accretion discs IV. Self-irradiation
  of the disc in the FU Orionis outburst phase

abstract:
  I investigate the self-irradiation of intensively accreting circumstellar
discs (backwarmed discs). It is modelled using the two-layer disc approach by
Lachaume et al. (2003) that includes heating by viscous dissipation and by an
external source of radiation. The disc is made of a surface layer directly
heated by the viscous luminosity of the central parts of the disc, and of an
interior heated by viscosity as well as by reprocessed radiation from the
surface. This model convincingly accounts for the infrared excess of some FU
Orionis objects in the range 1-200 microns and supports the backwarmed disc
hypothesis sometimes invoked to explain the mid- and far-infrared excesses
whose origins are still under debate. Detailed simulation of the vertical
radiative transfert in the presence of backwarming is still needed to
corroborate these results and spectroscopically constrain the properties of
intensively accreting discs.


title:
The Expansion of Space: Free Particle Motion and the Cosmological
  Redshift

abstract:
  The meaning of the expansion of the universe, or the `expansion of space,' is
explored using two phenomena: the motion of a test particle against a
homogeneous background and the cosmological redshift. Contrary to some
expectations, a particle removed from the Hubble flow never returns to it. The
cosmological redshift is not an `expansion effect;' in special cases it can be
separated into a kinematic (special relativistic) part and a static
(gravitational redshift) part, but in general must be thought of as the effect
on light rays of their propagation through curved space-time. Space as such
does not affect matter by `expanding,' but only through its curvature.


title: The Baikal Neutrino Telescope: Results, Plans, Lessons

abstract:
  We review recent results on the search for high energy extraterrestrial
neutrinos, neutrinos induced by WIMP annihilation and neutrinos coincident with
Gamma Ray Bursts as obtained with the Baikal neutrino telescope NT-200. We
describe the moderate upgrade of NT-200 towards a ~10 Mton scale detector
NT-200+. We finally draw a few lessons from our experience which may be of use
for other underwater experiments.


title: High-energy emission from the stellar wind collisions in gamma-2 Velorum

abstract:
  The binary system gamma-2 Velorum (WC8+O7.5) contains the nearest known
Wolf-Rayet star to the Sun, at a distance of 258$_{-31}^{+41}$ pc. Its strong
radio emission shows evidence for a partially absorbed nonthermal component,
which has been interpreted as synchrotron emission from electrons accelerated
in the colliding wind region. Inverse Compton cooling of these electrons in the
intense UV radiation field from the O-type companion star could produce a
significant hard X-ray and gamma-ray emission, whose flux depends on the ratio
of the energy densities of magnetic to seed photon fields. The Vela region was
observed with the INTEGRAL satellite in 2003, as part of the Core Programme. No
signals from gamma-2 Vel are detected in the images obtained with the
IBIS/ISGRI coded aperture instrument in the energy ranges 20-40 and 40-80 keV.
  From the derived 3$\sigma$ upper limits, we show that the average magnetic
field near the region of stellar wind collision should be relatively high,
greater than about 1 G. The high-energy emission of gamma-2 Vel might be
detected with the forthcoming GLAST experiment.


title:
The distance to the LMC cluster Reticulum from the K-band
  Period-Luminosity-Metallicity relation of RR Lyrae stars

abstract:
  We present new and accurate Near-Infrared J and Ks-band data of the Large
Magellanic Cloud cluster Reticulum. Data were collected with SOFI available at
NTT and covering an area of approximately (5 x 5) arcmin^2 around the center of
the cluster. Current data allowed us to derive accurate mean K-band magnitudes
for 21 fundamental and 9 first overtone RR Lyrae stars. On the basis of the
semi-empirical K-band Period-Luminosity-Metallicity relation we have recently
derived, we find that the absolute distance to this cluster is 18.52 +- 0.005
(random) +- 0.117 (systematic). Note that the current error budget is dominated
by systematic uncertainty affecting the absolute zero-point calibration and the
metallicity scale.


title:
Fluid Stability Below the Neutrinospheres of Supernova Progenitors and
  the Dominant Role of Lepto-Entropy Fingers

abstract:
  We have developed a formalism for analyzing the stability of a fluid in the
presence of neutrinos of all flavors and in the presence of a gravitational
field. When applied to an extensive two-dimensional grid of core radii and
fluid element sizes for each of several time slices of a number of
proto-supernovae, we find no evidence for the neutron finger instability as
described by the Livermore group. We find, instead, that the rate of lepton
equilibration always exceeds that of thermal equilibration. Furthermore, we
find that thermal diffusion driven by a lepton fraction difference and lepton
diffusion driven by an entropy difference are both nonzero and that the first
of these tends to be large in magnitude. An important consequence of this is
the presence of a doubly diffusive instability, which we refer to as
``lepto-entropy fingers,'' in an extensive region below the neutrinosphere
where the lepton number, $Y_{\ell}$, is small. This instability is driven by a
mechanism very different from that giving rise to neutron fingers, and may play
an important role in enhancing the neutrino emission. Deep in the core where
the entropy is low and the lepton number higher, our analysis indicates a
region unstable to another instability which we refer to as ``lepto-entropy
semiconvection.'' These instabilities, particularly lepto-entropy fingers, may
have already been seen in some multi-dimensional core collapse simulations
described in the literature.


title: Pulsar Kicks: Spin and Kinematic Constraints

abstract:
  It has been noted that the Crab and Vela pulsar proper motions lie along the
symmetry axes of their wind nebulae. In an effort to promote this observation
to a serious test of kick physics, we are using CXO images and other data to
estimate the angle between the proper motion and PWN (i.e. spin) axis for a
number of pulsars. Here we give a progress report on this work and the
constraints that these data provide on kick models. Present data suggest that a
kick duration of tau_K~3s is sufficient to explain the alignment of most
pulsars. This rules out E-M and hydrodynamic kick models, but is fairly
consistent with proposed anisotropic neutrino emission. However, some objects,
especially PSR J0538+2817 show such good alignment that even neutrino models
are challenged.


title: The effect of evaporation on the evolution of close-in giant planets

abstract:
  We include the effect of evaporation in our evolutionary calculations of
close-in giant planets, based on a recent model for thermal evaporation taking
into account the XUV flux of the parent star (Lammer et al. 2003). Our analysis
leads to the existence of a critical mass for a given orbital distance $m_{\rm
crit}(a)$ below which the evaporation timescale becomes shorter than the
thermal timescale of the planet. For planets with initial masses below $m_{\rm
crit}$, evaporation leads to a rapid expansion of the outer layers and of the
total planetary radius, speeding up the evaporation process. Consequently, the
planet does not survive as long as estimated by a simple application of mass
loss rates without following consistently its evolution. We find out that the
transit planet HD 209458b might be in such a dramatic phase, although with an
extremely small probability. As a consequence, we predict that, after a certain
time, only planets above a value $m_{\rm crit}(a)$ should be present at an
orbital distance $a$ of a star. For planets with initial masses above $m_{\rm
crit}$, evaporation does not affect the evolution of the radius with time.


title: X-Ray Eclipse Timing in the LMXB EXO0748-676

abstract:
  Orbital period changes are an important diagnostic for understanding low mass
X-ray binary (LMXB) accretion-induced angular momentum exchange and overall
system evolution. We present our most recent results for the eclipse timing of
the LMXB EXO0748-676. Since its discovery in 1985 it has apparently undergone
three distinct orbital period "epochs", each characterized by a different
orbital period than the previous epoch. We outline the orbital period behavior
for EXO0748-676 over the past 18 years and discuss the implications of this
behavior in light of current theoretical ideas for LMXB evolution.


title:
BUDDA: A New Two-Dimensional Bulge/Disk Decomposition Code for Detailed
  Structural Analysis of Galaxies

abstract:
  We present BUDDA (BUlge/Disk Decomposition Analysis), a new code devoted to
perform a two-dimensional bulge/disk decomposition directly from the images of
galaxies. The bulge component is fitted with a generalized Sersic profile
whereas disks have an exponential profile. No other components are included.
Bars and other sub-structures, like lenses, rings, inner bars and inner disks,
are studied with the residual images obtained through the subtraction of bulges
and disks from the original images. This means that a detailed structural
analysis of galaxies may be performed with a small number of parameters, and
sub-structures may be directly studied with no a priori assumptions. To
illustrate its usefulness, we present the results obtained with a sample of 51
mostly early-type galaxies (but covering the whole Hubble sequence). These
results show some of the applications in which the code may be used: the
determination of parameters for Fundamental Plane and structural studies,
quantitative morphological classification of galaxies and identification and
study of hidden sub-structures. We have determined the structural parameters of
the galaxies in our sample and found many examples of hidden inner disks in
ellipticals, secondary bars, nuclear rings and dust lanes in lenticulars and
spirals, and also wrong morphological classification cases.


title: The PSR J0514-4002A binary system in NGC 1851

abstract:
  Using the Giant Metrewave Radio Telescope (GMRT), we have discovered PSR
J0514-4002A, a binary millisecond pulsar in the globular cluster NGC 1851. This
pulsar has a rotational period of 4.99 ms and the most eccentric pulsar orbit
yet found: e = 0.89. The orbital period is 18.8 days, and companion has a
minimum mass of 0.9 M_sun; its nature is presently unclear. After accreting
matter from a low-mass stellar companion, this pulsar exchanged it for its more
massive present companion. This system presents the strongest evidence to date
of such a process.