title:
Wind clumping and the wind-wind collision zone in the Wolf-Rayet binary
  gamma Velorum

abstract:
  We present XMM-Newton observations of gamma^2 Velorum (WR 11, WC8+O7.5III, P
= 78.53 d), a nearby Wolf-Ray binary system, at its X-ray high and low states.
At high state, emission from a hot collisional plasma dominates from about 1 to
8 keV. At low state, photons between 1 and 4 keV are absorbed. The hot plasma
is identified with the shock zone between the winds of the primary Wolf-Rayet
star and the secondary O giant. The absorption at low state is interpreted as
photoelectric absorption in the Wolf-Rayet wind. This absorption allows us to
measure the absorbing column density and to derive a mass loss rate 8x10^{-6}
M_sun/yr for the WC8 star. This mass loss rate, in conjunction with a previous
Wolf-Rayet wind model, provides evidence for a clumped WR wind. A clumping
factor of 16 is required. The X-ray spectra below 1 keV (12 Ang) show no
absorption and are essentially similar in both states. There is a rather clear
separation in that emission from a plasma hotter than 5 MK is heavily absorbed
in low state while the cooler plasma is not. This cool plasma must come from a
much more extended region than the hot material. The Neon abundance in the
X-ray emitting material is 2.5 times the solar value. The unexpected detection
of CV (25.3 Ang) and CVI (31.6 Ang) radiative recombination continua at both
phases indicates the presence of a cool (~40,000 K) recombination region
located far out in the binary system.


title: X-ray nondetection of the Lyman-alpha Emitters at z ~ 4.5

abstract:
  The Lyman-alpha emitters found at z ~ 4.5 by the Large Area Lyman Alpha
(LALA) survey have high equivalent widths in the Lyman-alpha line, which can be
produced by either narrow-lined active galactic nuclei (AGNs) or by stellar
populations with a very high proportion of young, massive stars. To investigate
the AGN scenario, we obtained two deep Chandra exposures to study the X-ray
nature of the Lyman-alpha emitters. The 172 ks deep Chandra image on the LALA
Bootes field was presented in a previous paper (Malhotra et al. 2003), and in
this paper we present a new Chandra deep exposure (174 ks) on the LALA Cetus
field, which doubled our sample of X-ray imaged Lyman-alpha sources, and imaged
the brightest source among our Lyman-alpha emitters. None of the 101
Lyman-alpha sources covered by two Chandra exposures was detected individually
in X-ray, with a 3 sigma limiting X-ray flux of F_{0.5-10.0 keV} < 3.3 x
10^{-16} ergs/cm^2/s for on-axis targets. The sources remain undetectable in
the stacked image, implying a 3 sigma limit to the average luminosity of
L_{2-8keV} < 2.8 x 10^{42} ergs/s. The resulting X-ray to Lyman-alpha ratio is
> 21 times lower than the ratios for known high redshift type-II quasars.
Together with optical spectra obtained at Keck, we conclude that no evidence of
AGN activity was found among our Lyman-alpha emitters at z ~ 4.5.


title: Transition redshift from the V-reconstruction method

abstract:
  We show the effectiveness of using the procedure of the potential
reconstruction (the V-method) in the estimation of the transition redshift
corresponding to switch from deceleration to acceleration phase of the
Universe. We investigate the FRW models with dark energy by applying the
particle-like description of their dynamics. In this picture the evolution of
the universe is represented by motion of a fictitious particle in the
one-dimensional potential $V(a)$ or V(z)$ where $a$ is the scale factor and $z$
is the redshift. The V-method solves the inverse problem where we reconstruct
the potential function from empirical data. We use the Riess et al.'s gold and
gold+silver samples of SN Ia data in this reconstruction. In the same framework
we obtain both the estimates of the form of the equation of state for dark
energy and the transition redshift. We obtain that transition redshift is
$0.38_{-0.07}^{+0.10}$ (gold subset) and $0.37_{-0.07}^{+0.06}$ (gold+silver
sample) when the linear model of dark energy ($w(z)=w_{0} + w_{1}z$) and
$\Omega_{m,0}=0.3$ are assumed. We compare the estimation of transition
redshift with the Riess et al. results. The V-method also alows us to find the
value of Hubble function at the moment of transition.


title:
The Luminosity, Stellar Mass, and Number Density Evolution of Field
  Galaxies of Known Morphology from z = 0.5 - 3

abstract:
  The evolution of rest-frame B-band luminosities, stellar masses, and number
densities of field galaxies in the Hubble Deep Field North and South are
studied as a function of rest-frame B-band morphological type out to redshifts
z~3 using a sample of 1231 I < 27 galaxies with spectroscopic and photometric
redshifts. We find that the co-moving number, and relative number, densities of
ellipticals and spirals declines rapidly at z > 1, although examples exist at z
> 2. The number and number fraction of peculiar galaxies consistent with
undergoing major mergers rises consistently at redshifts z > 2. Through
simulations we argue that this decline is robust at the 4 sigma level against
morphological k-corrections and redshift effects. We trace the evolution of
rest-frame B-band luminosity density as a function of morphology out to z~3
finding that the luminosity density is steadily dominated by peculiars at z >
1.5 with a peak fraction of 60-90% at z~3. By z~0.5 B-band luminosity fractions
are similar to their local values. The stellar mass density follows a similar
trend as the luminosity density, with some important exceptions. At high
redshifts, z > 2, over 60-80% of stellar mass is attached to peculiars, while
at z< 1, 80-95% of stellar mass is attached to ellipticals and spirals. In
contrast to the luminosity density, the stellar mass density of ellipticals is
greater than spirals at z < 1.5, and the stellar masses in both types grow
together at z < 1, while number densities remain constant. (abridged)


title:
The Nature of Radio Continuum Emission in the Dwarf Starburst Galaxy NGC
  625

abstract:
  We present new multi-frequency radio continuum imaging of the dwarf starburst
galaxy NGC 625 obtained with the Very Large Array. Data at 20, 6, and 3.6 cm
reveal global continuum emission dominated by free-free emission, with only
mild synchrotron components. Each of the major HII regions is detected; the
individual spectral indices are thermal for the youngest regions (showing
strongest H Alpha emission) and nonthermal for the oldest. We do not detect any
sources that appear to be associated with deeply embedded, dense, young
clusters, though we have discovered one low-luminosity, obscured source that
has no luminous optical counterpart and which resides in the region of highest
optical extinction. Since NGC 625 is a Wolf-Rayet galaxy with strong recent
star formation, these radio properties suggest that the youngest star formation
complexes have not yet evolved to the point where their thermal spectra are
significantly contaminated by synchrotron emission. The nonthermal components
are associated with regions of older star formation that have smaller ionized
gas components. These results imply a range of ages of the HII regions and
radio components that agrees with our previous resolved stellar population
analysis, where an extended burst of star formation has pervaded the disk of
NGC 625 over the last ~ 50 Myr. We compare the nature of radio continuum
emission in selected nearby dwarf starburst and Wolf-Rayet galaxies,
demonstrating that thermal radio continuum emission appears to be more common
in these systems than in typical HII galaxies with less recent star formation
and more evolved stellar clusters.


title:
Chandra X-ray observations of Young Clusters II. Orion Flanking Fields
  Data

abstract:
  We present results of Chandra observations of two flanking fields (FF) in
Orion, outside the Orion Nebula Cluster (ONC). The observations were taken with
the ACIS-I camera with an exposure time of about 48 ks each field. We present a
catalog of 417 sources, which includes X-ray luminosity, optical and infrared
photometry and X-ray variability information. We have found 91 variable
sources, 33 of which have a flare-like light curve, and 11 of which have a
pattern of a steady increase or decrease over a 10 hour period. The optical and
infrared photometry for the stars identified as X-ray sources are consistent
with most of these objects being pre-main sequence stars with ages younger than
10 Myr. We present evidence for an age difference among the X-ray selected
samples of NGC 2264, Orion FF, and ONC, with NGC 2264 being the oldest, and ONC
being the youngest.


title: Discovery of a Variable Star Population in NGC 2808

abstract:
  We have applied the image subtraction method to images of the peculiar,
bimodal-horizontal branch globular cluster NGC 2808, taken over a total of six
nights over a range of five months. As a result, we have found, for the first
time, a sizeable population of variable stars in the crowded inner regions of
the cluster, thus raising the known RR Lyrae population in the cluster to a
total of 18 stars. In addition, an eclipsing binary and two other variables
with periods longer than 1 day were also found. Periods, positions and
(differential) light curves are provided for all the detected variables. The
Oosterhoff classification of NGC 2808, which has recently been associated with
a previously unknown dwarf galaxy in Canis Major, is briefly discussed.


title: Gamma ray bursts and the origin of galactic positrons

abstract:
  A recent observation of the 511 keV electron-positron annihilation line from
the Galactic bulge has prompted a debate on the origin of the galactic
positrons responsible for this emission. Assuming equilibrium between
annihilation and injection of positrons in the Galaxy, we investigate the
possibility that positrons were produced by past gamma ray bursts (GRBs). We
compare the positron annihilation rate inferred from the observed 511 keV line
with the predicted injection rate due to electron-positron pairs leaking out of
individual GRBs and those pairs produced by GRB photons in the dense molecular
clouds at the Galactic center. We conclude that the proposed scenario is
marginally consistent with observations, and can reproduce the observed
normalization of the annihilation line only for higher-than-average values of
the GRB rate in the Galaxy and/or the molecular clouds optical depth for pair
production.


title: Neutrinos from pre-supernova star

abstract:
  Analysis of the massive star properties during C, Ne, O and Si burning i.e.
the neutrino-cooled stage, leads to the simplified neutrino emission model. In
the framework of this model we have simulated spectrum of the antineutrinos.
Flux normalized according to the massive star model with explicitly given
neutrino luminosity allow us to predict signal produced in water Cherenkov
detectors. The results are discussed from the point of view of the possibility
of the core-collapse supernova event prediction in advance of a few days.


title: Low-order multipole maps of CMB anisotropy derived from WMAP

abstract:
  Recent analyses of the WMAP data have suggested that the low-order multipoles
of the CMB anisotropy distribution show cosmologically interesting and
unexpected morphologies and amplitudes. In this paper, we apply a power
equalization (PE) filter to the high-latitude WMAP data in order to reconstruct
these low-l multipoles free from the largest Galactic foreground modelling
uncertainties in the Galactic plane. The characteristic spatial distributions
of the modes of order l=2,3,4,5 have been determined as a function of
frequency, sky coverage and two methods for foreground correction: using the
template fitting results of Bennett et al. (2003) and by a simple linear
projection scheme assuming the spectral dependence of the foreground
components. Our analyses suggest that the K and Ka frequency bands remain
significantly contaminated by residual foreground emission for the WMAP Kp2
mask. However, the l=3,4,5 multipole maps for the Q, V and W channels indicate
that, after foreground cleaning, these multipoles are dominated by the CMB
anisotropy component. We confirm the Tegmark et al. (2003) result that the
octopole does indeed show structure in which its hot and cold spots are centred
on a single plane in the sky, and show further that this is very stable with
respect to the applied mask and foreground correction. The estimated quadrupole
is much less stable showing non-negligible dependence on the Galactic
foreground correction. Including these uncertainties is likely to weaken the
statistical significance of the claimed alignment between the quadrupole and
octopole. Nevertheless, these anisotropy patterns are also present for in
COBE-DMR data, and are unlikely to be associated with instrumental systematic
artifacts.


title: Design and Status of IceCube

abstract:
  IceCube is a kilometer-scale high energy neutrino detector that builds on the
wealth of experience accumulated with its smaller predecessor, AMANDA. An
international collaboration has begun construction of key components of the
IceCube detector and deployment operations at the South Pole will begin in late
2004.
  The underlying design of the IceCube detector and of the DAQ system are
presented here, emphasizing the digital optical modules (DOMs) as the smallest
discrete IceCube building block. The event reconstruction critically relies on
a relative timing accuracy from DOM to DOM of a few nanoseconds over inter-DOM
separations of up to 1 km.


title:
The Chemical Properties of Milky Way and M31 Globular Clusters: I. A
  Comparative Study

abstract:
  A comparative analysis is performed between high-quality integrated spectra
of 30 globular clusters in M31, 20 Milky Way clusters, and a sample of field
and cluster elliptical galaxies. We find that the Lick CN indices in the M31
and Galactic clusters are enhanced relative to the bulges of the Milky Way,
M31, and elliptical spheroids. Although not seen in the Lick CN indices, the
near-UV cyanogen feature (3883 A) is strongly enhanced in M31 clustesr with
respect to the Galactic globulars at metallicities, --1.5<[Fe/H]<--0.3. Carbon
shows signs of varying amongst these two groups. For [Fe/H]>--0.8, we observe
no siginificant differences in the Hdelta, Hgamma, or Hbeta indices between the
M31 and Galactic globulars. The sample of ellipticals lies offset from the loci
of all the globulars in the Cyanogen--[MgFe], and Balmer--[MgFe] planes. Six of
the M31 cluster spectra appear young, and are projected onto the M31 disk.
Population synthesis models suggest that these are metal-rich clusters with
ages 100--800 Myr, metallicities --0.20 < [Fe/H] <0.35, and masses 0.7
-7.0x10^4 Msun. Two other young clusters are Hubble V in NGC 205, and an older
(~3 Gyr) cluster ~7 kpc away from the plane of the disk. The six clusters
projected onto the disk rotate in a similar fashion to the HI gas in M31, and
three clusters exhibit thin disk kinematics (Morrison et al.). Dynamical masses
and structural parameters are required for these objects to determine whether
they are massive open clusters or globular clusters. If the latter, our
findings suggest globular clusters may trace the build up of galaxy disks. In
either case, we conclude that these clusters are part of a young, metal-rich
disk cluster system in M31, possibly as young as 1 Gyr old.


title: Galaxies and subhaloes in LCDM galaxy clusters

abstract:
  We combine 10 high resolution resimulations of cluster--sized dark haloes
with semi--analytic galaxy formation modelling in order to compare the number
density and velocity dispersion profiles of cluster galaxies with those of dark
matter substructures (subhaloes). While the radial distribution of galaxies
follows closely that of the dark matter, the distribution of dark matter
subhaloes is much less centrally concentrated. The velocity dispersion profiles
of galaxies are also very similar to those of the dark matter, while those for
subhaloes are biased high, particularly in the inner regions of clusters. We
explain how these differences, already clearly visible in earlier work, are a
consequence of the formation of galaxies at the centres of dark matter haloes.
Galaxies and subhaloes represent different populations and are not directly
comparable. Evolution produces a complex and strongly position--dependent
relation between galaxies and the subhaloes in which they reside. This relation
can be properly modelled only by appropriate physical representation of the
galaxy formation process.


title: Radio Jets in Cooling Cores

abstract:
  Almost every strong cooling core contains an active radio galaxy. Combined
radio and X-ray images reveal the dramatic interaction which is taking place
between the radio jet and the central cluster plasma. At least two important
questions can in principle be answered by comparing the new data to theoretical
models. The first is how the radio jet propagates, and disrupts, in the cooling
core environment: why are these cluster-center radio sources unusual? The
second is the effect the radio jet has on the cooling core: is it energetically
important to the core? Thanks to the new data we are beginning to be able to
answer these questions.


title:
Current Performance and On-Going Improvements of the 8.2 m Subaru
  Telescope

abstract:
  An overview of the current status of the 8.2 m Subaru Telescope constructed
and operated at Mauna Kea, Hawaii, by the National Astronomical Observatory of
Japan is presented. The basic design concept and the verified performance of
the telescope system are described. Also given are the status of the instrument
package offered to the astronomical community, the status of operation, and
some of the future plans. The status of the telescope reported in a number of
SPIE papers as of the summer of 2002 are incorporated with some updates
included as of 2004 February. However, readers are encouraged to check the most
updated status of the telescope through the home page,
http://subarutelescope.org/index.html, and/or the direct contact with the
observatory staff.


title: The Lyman-alpha Forest Power Spectrum from the Sloan Digital Sky Survey

abstract:
  We measure the power spectrum, P_F(k,z), of the transmitted flux in the
Ly-alpha forest using 3035 high redshift quasar spectra from the Sloan Digital
Sky Survey. This sample is almost two orders of magnitude larger than any
previously available data set, yielding statistical errors of ~0.6% and ~0.005
on, respectively, the overall amplitude and logarithmic slope of P_F(k,z). This
unprecedented statistical power requires a correspondingly careful analysis of
the data and of possible systematic contaminations in it. For this purpose we
reanalyze the raw spectra to make use of information not preserved by the
standard pipeline. We investigate the details of the noise in the data,
resolution of the spectrograph, sky subtraction, quasar continuum, and metal
absorption. We find that background sources such as metals contribute
significantly to the total power and have to be subtracted properly. We also
find clear evidence for SiIII correlations with the Ly-alpha forest and suggest
a simple model to account for this contribution to the power. While it is
likely that our newly developed analysis technique does not eliminate all
systematic errors in the P_F(k,z) measurement below the level of the
statistical errors, our tests indicate that any residual systematics in the
analysis are unlikely to affect the inference of cosmological parameters from
P_F(k,z). These results should provide an essential ingredient for all future
attempts to constrain modeling of structure formation, cosmological parameters,
and theories for the origin of primordial fluctuations.


title: An Interpretation of the $h\nu_{peak}$ - $E_{iso}$ Correlation for GRB

abstract:
  The $h\nu_{peak}/100 KeV \sim [E_{iso}/10^{52} \rm{erg}]^{1/2}$ correlation
reported recently by Amati et al. (2002) and Lamb et al. (2003) for long GRB's
can be interpreted as a viewing angle effect if the emitting region of the
fireball is ring-shaped.


title:
SALT and RR Lyrae variables: Our Galaxy, The Magellanic Clouds and the
  Local Group

abstract:
  A review is given of the possibilities for the study of the kinematics and
metallicities of the old populations in galaxies of the Local Group using
SALT/PFIS observations of RR Lyrae variables.


title: The early evolution of Globular Clusters: the case of NGC 2808

abstract:
  Enhancement and spread of helium among globular cluster stars have been
recently suggested as a way to explain the horizontal branch blue tails, in
those clusters which show a primordial spread in the abundances of CNO and
other elements involved in advanced CNO burning (D'Antona et al. 2002). In this
paper we examine the implications of the hypothesis that, in many globular
clusters, stars were born in two separate events: an initial burst (first
generation), which gives origin to probably all high and intermediate mass
stars and to a fraction of the cluster stars observed today, and a second,
prolonged star formation phase (second generation) in which stars form directly
from the ejecta of the intermediate mass stars of the first generation. In
particular, we consider in detail the morphology of the horizontal branch in
NGC 2808 and argue that it unveils the early cluster evolution, from the birth
of the first star generation to the end of the second phase of star formation.
This framework provides a feasible interpretation for the still unexplained
dichotomy of NGC 2808 horizontal branch, attributing the lack of stars in the
RR Lyr region to the gap in the helium content between the red clump, whose
stars are considered to belong to the first stellar generation and have
primordial helium, and the blue side of the horizontal branch, whose minimum
helium content reflects the helium abundance in the smallest mass
(~4Msun)contributing to the second stellar generation. This scenario provides
constraints on the required Initial Mass Function, in a way that a great deal
of remnant neutron stars and stellar mass black holes might have been produced.


title: High-mass microquasars and low-latitude gamma-ray sources

abstract:
  Population studies of unidentified EGRET sources suggest that there exist at
least three different populations of galactic gamma-ray sources. One of these
populations is formed by young objects distributed along the galactic plane
with a strong concentration toward the inner spiral arms of the Galaxy.
Variability, spectral and correlation analysis indicate that this population is
not homogeneous. In particular, there is a subgroup of sources that display
clear variability in their gamma-ray fluxes on timescales from days to months.
Following the proposal by Kaufman Bernad\'o et al. (2002), we suggest that this
group of sources might be high-mass microquasars, i.e. accreting black holes or
neutron stars with relativistic jets and early-type stellar companions. We
present detailed inhomogeneous models for the gamma-ray emission of these
systems that include both external and synchrotron self-Compton interactions.
We have included effects of interactions between the jet and all external
photon fields to which it is exposed: companion star, accretion disk, and hot
corona. We make broadband calculations to predict the spectral energy
distribution of these objects from radio up to GeV energies. The results and
predictions can be tested by present and future gamma-ray instruments like
INTEGRAL, AGILE, and GLAST.


title:
Chemical abundances of planetary nebulae towards the direction of the
  galactic anticenter

abstract:
  In this paper we report new observations and derive chemical abundances for a
sample of 26 planetary nebulae (PN) located in the anticenter direction. Most
of these nebulae are far away objects, located at galactocentric distances
greater than about 8 kpc, so that they are particularly useful for the
determination of the radial gradients at large distances from the galactic
center. A comparison of the present results with previously determined
abundances suggests that the radial abundance gradients flatten out at
distances larger than about 10 kpc from the center.


title: The Density of Coronal Plasma in Active Stellar Coronae

abstract:
  We have analyzed high-resolution X-ray spectra of a sample of 22 active stars
observed with the High Energy Transmission Grating Spectrometer on {\em
Chandra} in order to investigate their coronal plasma density. Densities where
investigated using the lines of the He-like ions O VII, Mg XI, and Si XIII.
While Si XIII lines in all stars of the sample are compatible with the
low-density limit, Mg XI lines betray the presence of high plasma densities ($>
10^{12}$ cm$^{-3}$) for most of the sources with higher X-ray luminosity ($>
10^{30}$ erg/s); stars with higher $L_X$ and $L_X/L_{bol}$ tend to have higher
densities at high temperatures. Ratios of O VII lines yield much lower
densities of a few $10^{10}$ cm$^{-3}$, indicating that the ``hot'' and
``cool'' plasma resides in physically different structures. Our findings imply
remarkably compact coronal structures, especially for the hotter plasma
emitting the Mg XI lines characterized by coronal surface filling factor,
$f_{MgXI}$, ranging from $10^{-4}$ to $10^{-1}$, while we find $f_{OVII}$
values from a few $10^{-3}$ up to $\sim 1$ for the cooler plasma emitting the O
VII lines. We find that $f_{OVII}$ approaches unity at the same stellar surface
X-ray flux level as solar active regions, suggesting that these stars become
completely covered by active regions. At the same surface flux level,
$f_{MgXI}$ is seen to increase more sharply with increasing surface flux. These
results appear to support earlier suggestions that hot $10^7$ K plasma in
active coronae arises from flaring activity, and that this flaring activity
increases markedly once the stellar surface becomes covered with active
regions.


title: Observations of jet dissipation

abstract:
  We summarise the recent progress of a project to determine physical
conditions in the jets of low-luminosity (FR I) radio galaxies. We model the
jets as intrinsically symmetrical, relativistic, decelerating flows. By fitting
to deep, high-resolution VLA images in total intensity and linear polarization,
we have been able to derive for the first time the three-dimensional
distributions of velocity, rest-frame emissivity and magnetic-field structure.
We describe our results for four sources and outline the implications for
theories of jet deceleration. We also summarise a conservation-law analysis of
3C 31, which gives profiles of internal pressure, density, Mach number and
entrainment rate along the jets, again for the first time. Finally, we discuss
the applicability of adiabatic models to FR I jets and identify the regions
where distributed particle acceleration is necessary


title:
Substructure Analysis of Selected Low Richness 2dFGRS Clusters of
  Galaxies

abstract:
  Complementary one-, two-, and three-dimensional tests for detecting the
presence of substructure in clusters of galaxies are applied to recently
obtained data from the 2dF Galaxy Redshift Survey. The sample of 25 clusters
used in this study includes 16 clusters not previously investigated for
substructure. Substructure is detected at or greater than the 99% CL level in
at least one test for 21 of the 25 clusters studied here. From the results, it
appears that low richness clusters commonly contain subclusters participating
in mergers. About half of the clusters have two or more components within 0.5
h^{-1} Mpc of the cluster centroid, and at least three clusters (Abell 1139,
Abell 1663, and Abell S333) exhibit velocity-position characteristics
consistent with the presence of possible cluster rotation, shear, or infall
dynamics. The geometry of certain features is consistent with influence by the
host supercluster environments. In general, our results support the hypothesis
that low richness clusters relax to structureless equilibrium states on very
long dynamical time scales (if at all).


title: Rotation periods for very low mass stars in the Pleiades

abstract:
  We present the results of a photometric monitoring campaign for very low mass
(VLM) members of the Pleiades. Periodic photometric variability was detected
for nine VLM stars with masses between 0.08 and 0.25 MS. These variations are
most likely caused by co-rotating, magnetically induced spots. In comparison
with solar-mass stars, the photometric amplitudes are very low (<0.04 mag),
implying that either the fraction of the spot-covered area, the asymmetry of
the spot distribution, or the contrast between spots and photospheric
environment decreases with mass. From our lightcurves, there is evidence for
temporal evolution of the spot patterns on timescales of about two weeks. The
rotation periods range from 2.9 h to 40 h and tend to increase linearly with
mass. Compared with more massive stars, we clearly see a lack of slow rotators
among VLM objects. The rotational evolution of VLM stars is investigated by
evolving the previously published periods for very young objects (Scholz &
Eisloeffel 2004) forward in time, and comparing them with those observed here
in the Pleiades. We find that the combination of spin-up by pre-main sequence
contraction and exponential angular momentum loss through stellar winds is able
to reproduce the observed period distribution in the Pleiades. This result may
be explained as a consequence of convective, small-scale magnetic fields.


title: SPI Measurements of the Diffuse Galactic Hard X-ray Continuum

abstract:
  INTEGRAL Spectrometer SPI data from the first year of the Galactic Centre
Deep Exposure has been analysed for the diffuse continuum from the Galactic
ridge. A new catalogue of sources from the INTEGRAL Imager IBIS has been used
to account for their contribution to the celestial signal. Apparently diffuse
emission is detected at a level ~10% of the total source flux. A comparison of
the spectrum of diffuse emission with that from an analysis of IBIS data alone
shows that they are consistent. The question of the contribution of unresolved
sources to this ridge emission is still open.


title: Growth of massive black holes by super-Eddington accretion

abstract:
  Narrow-Line Seyfert 1 galaxies (NLS1s) and Narrow-Line quasars (NLQs) seem to
amount to ~ 10-30 % of active galactic nuclei (AGNs) in the local universe.
Together with their average accretion rate, we argue that the black hole (BH)
growth by factor of 8-800 happens in these super-Eddington accretion phase of
AGNs. Moreover, there is a possible, systematic underestimation of accretion
rates (in the Eddington unit) due to an overestimation of BH mass by massive
accretion discs for super-Eddington objects. If it is true, the factor of BH
growth above may be larger by order(s) of magnitude. In contrast, the growth
factor expected in sub-Eddington phase is only ~ 2. Therefore, the cosmic BH
growth by accretion is likely dominated by super-Eddington phase, rather than
sub-Eddington phase which is the majority among AGNs.
  This analysis is based on the fraction and the average accretion rate of
NLS1s and NLQs obtained for z ~< 0.5. If those numbers are larger at higher
redshift (where BHs were probably less grown), super-Eddington accretion would
be even more important in the context of cosmic BH growth history.


title: The ELODIE archive

abstract:
  The ELODIE archive contains the complete collection of high-resolution
echelle spectra accumulated over the last decade using the ELODIE spectrograph
at the Observatoire de Haute-Provence 1.93-m telescope. This article presents
the different data products and the facilities available on the web to
re-process these data on-the-fly. Users can retrieve the data in FITS format
from http://atlas.obs-hp.fr/elodie and apply to them different functions:
wavelength resampling and flux calibration in particular.


title:
The Chandra Deep Field-North Survey: XVII. Evolution of magnetic
  activity in old late-type stars

abstract:
  The extremely sensitive Chandra Deep Field-North (CDF-N) pencil-beam X-ray
survey is used to identify and characterize the X-ray emission from old
high-latitude main sequence Galactic stars. Our principal goal is to
investigate the expected long-term decay of magnetic activity of late-type
stars due to the gradual spindown of stellar rotation from a magnetized stellar
wind. Eleven X-ray sources constitute a well-defined sample of 2 G, 2 K0-K4,
and 7 M2-M5 stars with median distance around 300 pc. X-ray luminosities are
typically log Lx ~ 27 erg/s and is dominated by flares rather than quiescent
coronal emission. Models of the population indicates that the CDF-N stars are
the most magnetically active old disk stars. A substantial decline in X-ray
luminosities over the 1<t<11 Gyr age interval is required. This is the first
demonstration that the coronal and flaring components of stellar magnetic
activity -- and presumably the interior magnetic dynamos responsible for the
reconnecting fields at the stellar surface -- exhibit long-term decay over the
age of the Galactic disk. The model that best fits the magnitudes, spectral
types and X-ray luminosities of the sample has Lx ~ 1/t^2 erg/s which is faster
than the 1/t decay rate predicted from widely accepted rotational spindown
rates and X-ray-activity relations.


title:
Full--Sphere Simulations of a Circulation--Dominated Solar Dynamo:
  Exploring the Parity Issue

abstract:
  We explore a two-dimensional kinematic solar dynamo model in a full sphere,
based on the helioseismically determined solar rotation profile and with an
$\alpha$ effect concentrated near the solar surface, which captures the
Babcock--Leighton idea that the poloidal field is created from the decay of
tilted bipolar active regions. The meridional circulation, assumed to penetrate
slightly below the tachocline, plays an important role. Some doubts have
recently been raised regarding the ability of such a model to reproduce
solar-like dipolar parity. We specifically address the parity issue and show
that the dipolar mode is preferred when certain reasonable conditions are
satisfied, the most important condition being the requirement that the poloidal
field should diffuse efficiently to get coupled across the equator. Our model
is shown to reproduce various aspects of observational data, including the
phase relation between sunspots and the weak, diffuse field.


title: The mass estimate in narrow-line Seyfert 1 galaxies

abstract:
  It is possible that narrow-line Seyfert 1 galaxies (NLS1s) are in the early
stage of active galactic nuclei (AGNs) evolution. It is important to estimate
the mass of supermassive black hole (SBH) in NLS1s. Here we considered the
different kinds of methods to estimate the SBH masses in NLS1s. The virial mass
from the H$\beta$ linewidth assuming random orbits of broad line regions (BLRs)
is consistent with that from the statured soft X-ray luminosity, which showed
that most of NLS1s are in the super-Eddington accretion state. The mass from
the [O III] linewidth is systematically larger than that from above two
methods. It is necessary to measure he bulge stellar dispersion and/or bulge
luminosity in NLS1s.


title: Fifty-Nine Reasons for a Supernova to not Explode

abstract:
  The number in the title is a birthday-inspired overestimate by about an order
of magnitude. Nevertheless, this contribution reminds of well-known reasons
that prevented straightforward explosions in many numerical supernova models.
It emphasizes a separation between the two events of core collapse and
supernova explosion.


title: The U-band Galaxy Luminosity Function of Nearby Clusters

abstract:
  Despite the great potential of the U-band galaxy luminosity function (GLF) to
constrain the history of star formation in clusters, to clarify the question of
variations of the GLF across filter bands, to provide a baseline for
comparisons to high-redshift studies of the cluster GLF, and to estimate the
contribution of bound systems of galaxies to the extragalactic near-UV
background, determinations have so far been hampered by the generally low
efficiency of detectors in the U-band and by the difficulty of constructing
both deep and wide surveys. In this paper, we present U-band GLFs of three
nearby, rich clusters to a limit of M_U=-17.5 (M*_U+2). Our analysis is based
on a combination of separate spectroscopic and R-band and U-band photometric
surveys. For this purpose, we have developed a new maximum-likelihood algorithm
for calculating the luminosity function that is particularly useful for
reconstructing the galaxy distribution function in multi-dimensional spaces
(e.g., the number of galaxies as a simultaneous function of luminosity in
different filter bands, surface brightness, star formation rate, morphology,
etc.), because it requires no prior assumptions as to the shape of the
distribution function.
  The composite luminosity function can be described by a Schechter function
with characteristic magnitude M*_U=-19.82+/-0.27 and faint end slope
alpha_U=-1.09+/-0.18. The total U-band GLF is slightly steeper than the R-band
GLF, indicating that cluster galaxies are bluer at fainter magnitudes.
Quiescent galaxies dominate the cumulative U-band flux for M_U<-14. The
contribution of galaxies in nearby clusters to the U-band extragalactic
background is <1% Gyr^-1 for clusters of masses ~3*10^14 to 2*10^15 M_solar.


title:
The Structure, Kinematics and Physical Properties of the Molecular Gas
  in the Starburst Nucleus of NGC 253

abstract:
  We present 5.2" x 2.6" resolution interferometry of CO J=1-0 emission from
the starburst galaxy NGC 253. The high spatial resolution of these new data, in
combination with recent high resolution maps of 13CO, HCN and near-infrared
emission, allow us for the first time to link unambiguously the gas properties
in the central starburst of NGC 253 with its bar dynamics. We confirm that the
star formation results from bar-driven gas flows as seen in "twin peaks"
galaxies. Two distinct kinematic features are evident from the CO map and
position-velocity diagram: a group of clouds rotating as a solid body about the
kinematic center of the galaxy, and a more extended gas component associated
with the near-infrared bar. We model the line intensities of CO, HCN and 13CO
to infer the physical conditions of the gas in the nucleus of NGC 253. The
results indicate increased volume densities around the radio nucleus in a
twin-peaks morphology. Compared with the CO kinematics, the gas densities
appear highest near the radius of a likely inner Linblad resonance, and
slightly lead the bar minor axis. This result is similar to observations of the
face-on, twin-peaks galaxy NGC 6951, and is consistent with models of starburst
generation due to gas inflow along a bar.


title: Two simple problems in semiclassical dense matter physics

abstract:
  The aim of this lecture is to discuss in some detail two simple but important
problems which have considerable importance for the development of theoretical
work in semiclassical dense matter physics.


title:
First Results from the Cryogenic Dark Matter Search in the Soudan
  Underground Lab

abstract:
  We report the first results from a search for weakly interacting massive
particles (WIMPs) in the Cryogenic Dark Matter Search (CDMS) experiment at the
Soudan Underground Laboratory. Four Ge and two Si detectors were operated for
52.6 live days, providing 19.4 kg-d of Ge net exposure after cuts for recoil
energies between 10--100 keV. A blind analysis was performed using only
calibration data to define the energy threshold and selection criteria for
nuclear-recoil candidates. Using the standard dark-matter halo and
nuclear-physics WIMP model, these data set the world's lowest exclusion limits
on the coherent WIMP-nucleon scalar cross-section for all WIMP masses above 15
GeV, ruling out a significant range of neutralino supersymmetric models. The
minimum of this limit curve at the 90% C.L. is 4 x 10^{-43} cm^2 at a WIMP mass
of 60 GeV.


title: A dichotomy in dust-jet orientation in radio galaxies

abstract:
  We have analyzed the position angle (PA) differences between radio jets and
dust distributions in the centers of Fanaroff & Riley Type 1 (FRI) radio
galaxies. We model the observed PA differences to infer the three-dimensional
relative orientation of jet and dust. Our main conclusion is that there is a
dichotomy in dust-jet-galaxy orientation both in projection and in
three-dimensional space. The orientation dichotomy can explain the
contradictory results obtained in previous studies. We briefly mention
scenarios that might explain the dichotomy.


title: Clustering of Submillimeter-Selected Galaxies

abstract:
  Using accurate positions from very deep radio observations to guide
multi-object Keck spectroscopy, we have determined a substantially complete
redshift distribution for very luminous, distant submillimeter(submm)-selected
galaxies (SMGs). A sample of 73 redshifts for SMGs in 7 fields contains a
surprisingly large number of `associations': systems of SMGs with Mpc-scale
separations, and redshifts within 1200 km/s. This sample provides tentative
evidence of strong clustering of SMGs at redshifts z~2-3 with a correlation
length of about 6.9 +- 2.1 Mpc/h, using a simple pair-counting approach that is
appropriate to the small, sparse SMG samples. This is somewhat greater than the
well-determined correlation lengths for both z~3 optical-ultraviolet(UV)
color-selected Lyman-break galaxies (LBGs) and z~2 QSOs. This could indicate
that SMGs trace the densest large-scale structures in the high-redshift
Universe, and that they may either be evolutionarily distinct from LBGs and
QSOs, or subject to a more complex astrophysical bias.


title:
Computer Simulations of Nonthermal Particles in Clusters of Galaxies:
  Application to the Coma Cluster

abstract:
  We have developed a numerical model for the temporal evolution of particle
and photon spectra resulting from nonthermal processes at the shock fronts
formed in merging clusters of galaxies. Fermi acceleration is approximated by
injecting power-law distributions of particles during a merger event, subject
to constraints on maximum particle energies. We consider synchrotron,
bremsstrahlung, Compton, and Coulomb processes for the electrons, nuclear,
photomeson, and Coulomb processes for the protons, and knock-on electron
production during the merging process. The broadband radio through $\gamma$-ray
emission radiated by nonthermal protons and primary and secondary electrons is
calculated both during and after the merger event. To test the ability of the
computer model to accurately calculate the nonthermal emission expected from a
cluster merger event, we apply the model to the Coma cluster of galaxies, and
show that the centrally located radio emission and the Hard X-ray excess
observed at 40-80$\kev$ is well fit by our model. If our model is correct, then
the Coma cluster will be significantly detected with GLAST and ground-based air
Cherenkov telescopes.


title: Millimeter and Submillimeter Survey of the R Corona Australis Region

abstract:
  Using a combination of data from the Antarctic Submillimeter Telescope and
Remote Observatory (AST/RO), the Arizona Radio Observatory Kitt Peak 12m
telescope and the Arizona Radio Observatory 10m Heinrich Hertz Telescope, we
have studied the most active part of the R CrA molecular cloud in multiple
transitions of Carbon Monoxide, HCO$^+$ and 870\micron continuum emission.
Since R CrA is nearby (130 pc), we are able to obtain physical spatial
resolution as high as 0.01pc over an area of 0.16 pc$^2$, with velocity
resolution finer than 1 km/s. Mass estimates of the protostar driving the
mm-wave emission derived from HCO$^+$, dust continuum emission and kinematic
techniques point to a young, deeply embedded protostar of $\sim$0.5-0.75
M$_\odot$, with a gaseous envelope of similar mass. A molecular outflow is
driven by this source that also contains at least 0.8 M$_\odot$ of molecular
gas with $\sim$0.5 L$_\odot$ of mechanical luminosity. HCO$^+$ lines show the
kinematic signature of infall motions as well as bulk rotation. The source is
most likely a Class 0 protostellar object not yet visible at near-IR
wavelengths. With the combination of spatial and spectral resolution in our
data set, we are able to disentangle the effects of infall, rotation and
outflow towards this young object.


title: Ten Years of Super Star Cluster Research

abstract:
  This conference demonstrated the tremendous progress that has been made in
the last decade in our observational and theoretical understanding of compact,
young, massive star clusters. One of the Hubble Space Telescope's main
achievements was to show that these are young analogues of classical globular
clusters and form in profusion in the local universe. They are now recognized
as key players in the problems of galaxy evolution and star formation. A major
result of the conference is the commonality of the star and cluster formation
process across an astonishing range of environments and scales. With the demise
of HST, the focus of the field will probably shift to the critical early phases
of cluster formation and evolution as revealed with new infrared and radio/mm
facilities.


title: Muon and Tau Neutrinos Spectra from Solar Flares

abstract:
  Solar neutrino flares and mixing are considered. Most power-full solar flare
as the ones occurred on 23th February 1956, September 29th 1989, 28th October
and on 2nd-4th November 2003 are sources of cosmic rays, X, gamma and neutrino
bursts. These flares took place both on front or in the edge and in the hidden
solar disk. The observed and estimated total flare energy should be a source of
a prompt secondary neutrino burst originated, by proton-proton-pion production
on the sun itself; a more delayed and spread neutrino flux signal arise by the
solar charged flare particles reaching the terrestrial atmosphere. Our first
estimates of neutrino signals in largest underground detectors hint for few
events in correlation with, gamma,radio onser. Our approximated spectra for
muons and taus from these rare solar eruption are shown over the most common
background. The muon and tau signature is very peculiar and characteristic over
electron and anti-electron neutrino fluxes. The rise of muon neutrinos will be
detectable above the minimal muon threshold of 113 MeV. The rarest tau
appearence will be possible only for hardest solar neutrino energies above
3.471 GeV


title: Effects of Ellipticity and Shear on Gravitational Lens Statistics

abstract:
  We study the effects of ellipticity in lens galaxies and external tidal shear
from neighboring objects on the statistics of strong gravitational lenses. For
isothermal lens galaxies normalized so that the Einstein radius is independent
of ellipticity and shear, ellipticity {\it reduces} the lensing cross section
slightly, and shear leaves it unchanged. Ellipticity and shear can
significantly enhance the magnification bias, but only if the luminosity
function of background sources is steep. Realistic distributions of ellipticity
and shear {\it lower} the total optical depth by a few percent for most source
luminosity functions, and increase the optical depth only for steep luminosity
functions. The boost in the optical depth is noticeable (>5%) only for surveys
limited to the brightest quasars (L/L_* > 10). Ellipticity and shear broaden
the distribution of lens image separations but do not affect the mean.
Ellipticity and shear naturally increase the abundance of quadruple lenses
relative to double lenses, especially for steep source luminosity functions,
but the effect is not enough (by itself) to explain the observed
quadruple-to-double ratio. With such small changes to the optical depth and
image separation distribution, ellipticity and shear have a small effect on
cosmological constraints from lens statistics: neglecting the two leads to
biases of just Delta Omega_M = 0.00 \pm 0.01 and Delta Omega_Lambda = -0.02 \pm
0.01 (where the errorbars represent statistical uncertainties in our
calculations).


title: Constraining Born-Infeld models of dark energy with CMB anisotropies

abstract:
  We study the CMB constraints on two Dark Energy models described by scalar
fields with different Lagrangians, namely a Klein-Gordon and a Born-Infeld
field. The speed of sound of field fluctuations are different in these two
theories, and therefore the predictions for CMB and structure formation are
different. Employing the WMAP data on CMB, we make a likelihood analysis on a
grid of theoretical models. We constrain the parameters of the models and
compute the probability distribution functions for the equation of state. We
show that the effect of the different sound speeds affects the low multipoles
of CMB anisotropies, but is at most marginal for the class of models studied
here.


title:
Spectroscopic source redshifts and parameter constraints from weak
  lensing and CMB

abstract:
  Weak lensing is a potentially robust and model-independent cosmological
probe, but its accuracy is dependent on knowledge of the redshift distribution
of the source galaxies used. The most robust way to determine the redshift
distribution is via spectroscopy of a subsample of the source galaxies. We
forecast constraints from combining CMB anisotropies with cosmic shear using a
spectroscopically determined redshift distribution, varying the number of
spectra $N_{spec}$ obtained from 64 to $\infty$. The source redshift
distribution is expanded in a Fourier series, and the amplitudes of each mode
are considered as parameters to be constrained via both the spectroscopic and
weak lensing data. We assume independent source redshifts, and consider in what
circumstances this is a good approximation (the sources are clustered and for
narrow spectroscopic surveys with many objects this results in the redshifts
being correlated). It is found that for the surveys considered and for a prior
of 0.04 on the calibration parameters, the addition of redshift information
make significant improvements on the constraints on the cosmological
parameters; however, beyond $N_{spec}\sim$few$\times 10^3$ the addition of
further spectra will make only a very small improvement to the cosmological
parameters. We find that a better calibration makes large $N_{spec}$ more
useful. Using an eigenvector analysis, we find that the improvement continues
with even higher $N_{spec}$, but not in directions that dominate the
uncertainties on the standard cosmological parameters.


title: The K Band Luminosity Functions of Galaxies in High Redshift Clusters

abstract:
  K band luminosity functions (LFs) of three, massive, high redshift clusters
of galaxies are presented. The evolution of K*, the characteristic magnitude of
the LF, is consistent with purely passive evolution, and a redshift of forma
tion z = 1.5-2.


title: Observations of Water Vapor Outflow from NML Cygnus

abstract:
  We report new observations of the far infrared and submillimeter water vapor
emission of NML Cygnus based on data gathered with the Infrared Space
Observatory and the Submillimeter Wave Astronomy Satellite. We compare the
emission from NML Cyg to that previously published for VY CMa and W Hya in an
attempt to establish the validity of recently proposed models for the outflow
from evolved stars. The data obtained support the contention by Ivezi\'{c} &
Elitzur (1995, 1997) that the atmospheres of evolved stars obey a set of
scaling laws in which the optical depth of the outflow is the single most
significant scaling parameter, affecting both the radiative transfer and the
dynamics of the outflow. Specifically, we provide observations comparing the
water vapor emission from NML Cyg, VY CMa and W Hya, and find, to the extent
permitted by the quality of our data, that the results are in reasonable
agreement with a model developed by Zubko & Elitzur (2000). Using this model we
derive a mass loss based on the dust opacities, spectral line fluxes, and
outflow velocities of water vapor observed in the atmospheres of these
oxygen-rich giants. For VY CMa and NML Cyg we also obtain an estimate of the
stellar mass.


title:
Multi-wavelength analysis of the dust emission in the Small Magellanic
  Cloud

abstract:
  We present an analysis of dust grain emission in the diffuse interstellar
medium of the Small Magellanic Cloud (SMC). This study is motivated by the
availability of 170 microns ISOPHOT data covering a large part of the SMC, with
a resolution enabling to disentangle the diffuse medium from the star forming
regions. After data reduction and subtraction of Galactic foreground emission,
we used the ISOPHOT data together with HiRes IRAS data and ATCA/Parkes combined
HI column density maps to determine dust properties for the diffuse medium. We
found a far infrared emissivity per hydrogen atom 30 times lower than the Solar
Neighborhood value. The modeling of the spectral energy distribution of the
dust, taking into account the enhanced interstellar radiation field, gives a
similar conclusion for the smallest grains (PAHs and very small grains)
emitting at shorter wavelength. Assuming Galactic dust composition in the SMC,
this result implies a difference in the gas-to-dust ratio (GDR) 3 times larger
than the difference in metallicity. This low depletion of heavy elements in
dust could be specific of the diffuse ISM and not apply for the whole SMC dust
if it results from efficient destruction of dust by supernovae explosions.


title:
Diffusion of Ultra High Energy Protons in Galaxy Clusters and Secondary
  X and Gamma Ray Emissions

abstract:
  In this work we simulate the propagation of Ultra High Energy (UHE) protons
in the magnetised intergalactic medium of Galaxy Clusters (GCs). Differently
from previous works on the subject, we trace proton trajectories in
configurations of the Intra Cluster Magnetic Field (ICMF) which have been
extracted from a constrained Magnetic-SPH simulation of the local universe.
Such an approach allows us to take into account the effects of several features
of the ICMFs, e.g. irregular geometrical structure and field fluctuations due
to merger shocks,which cannot be investigated analitically or with usual
numerical simulations. Furthermore, we are able to simulate a set of clusters
which have properties quite similar to those of GCs observed in the nearby
universe. We estimate the time that UHE protons take to get out of the clusters
and found that in the energy range $5\times 10^{18} \simleq E \simleq 3 \times
10^{19} \eV$ proton propagation takes place in the Bohm scattering diffusion
regime passing smoothly to a small pitch angle diffusion regime at larger
energies.
  We apply our results to estimate the secondary gamma and Hard X Ray (HXR)
emissions produced by UHE protons in a rich GC. We show that the main emission
channel is due to the synchrotron HXR radiation of secondary electrons
originated by proton photo-pair production scattering onto the CMB. This
process may give rise to a detectable signal if a relatively powerful AGN, or a
dead quasar, accelerating protons at UHEs is harboured by a rich GC in the
local universe.


title: Feeding AGN: new results from the NUGA survey

abstract:
  The NUGA project is a high-resolution (0.5''-1'') CO survey of low luminosity
AGN including the full sequence of activity types (Seyferts, LINERs and
transition objects). NUGA aims to systematically study the different mechanisms
for gas fueling of AGNs in the Local Universe. In this paper we discuss the
latest results of this recently completed survey, which now includes newly
acquired subarcsec resolution observations for all targets of the sample. The
large variety of circumnuclear disk morphologies found in NUGA galaxies (m=1,
m=2 and stochastic instabilities) is a challenging result that urges the
refinement of current dynamical models. In this paper we report on new results
obtained in 4 study cases for NUGA: NGC4826, NGC7217, NGC4579 and NGC6951


title:
Impact of Varying Atmospheric Profiles on Extensive Air Shower
  Observation: - Atmospheric Density and Primary Mass Reconstruction -

abstract:
  The longitudinal profile of extensive air showers is sensitive to the energy
and type/mass of the primary particle. One of its characteristics, the
atmospheric depth of shower maximum, is often used to reconstruct the elemental
composition of primary cosmic rays. In this article, the impact of the
atmospheric density profile on the reconstruction of the depth of maximum, as
observed in fluorescence light measurements, is investigated. We consider in
detail the atmospheric density profile and its time variations at the site of
the southern Pierre Auger Observatory, using data that were obtained from
meteorological radio soundings. Similar atmospheric effects are expected to be
found also at other sites.


title: Galactic Evolution of Nitrogen

abstract:
  We present detailed spectroscopic analysis of nitrogen abundances in 31
unevolved metal-poor stars analysed by spectral synthesis of the near-UV NH
band at 3360 A observed at high resolution with various telescopes. We found
that [N/Fe] scales with that of iron in the metallicity range -3.1 < [Fe/H] <0
with the slope 0.01+-0.02. Furthermore, we derive uniform and accurate (N/O)
ratios using oxygen abundances from near-UV OH lines obtained in our previous
studies. We find that a primary component of nitrogen is required to explain
the observations. The NH lines are discovered in the VLT/UVES spectra of the
very metal-poor subdwarfs G64-12 and LP815-43 indicating that these stars are N
rich. The results are compared with theoretical models and observations of
extragalactic HII regions and Damped Ly$\alpha$ systems. This is the first
direct comparison of the (N/O) ratios in these objects with those in Galactic
stars.


title: Cu and Zn in the early Galaxy

abstract:
  We present Cu and Zn abundances for 38 FGK stars, mostly dwarfs, spanning a
metallicity range between solar and [Fe/H] =-3. The abundances were obtained
using Kurucz's local thermal equilibrium (LTE) model atmospheres and the
near-UV lines of CuI 3273.95 A and ZnI 3302.58 A observed at high spectral
resolution. The trend of [Cu/Fe] versus [Fe/H] is almost solar for [Fe/H] > -1
and then decreases to a plateau <[Cu/Fe]> =-0.98 at [Fe/H] <-2.5, whereas the
[Zn/Fe] trend is essentially solar for [Fe/H] >-2 and then slightly increases
at lower metallicities to an average value of <[Zn/Fe]> =+ 0.18. We compare our
results with previous work on these elements, and briefly discuss them in terms
of nucleosynthesis processes. Predictions of halo chemical evolution fairly
reproduce the trends, especially the [Cu/Fe] plateau at very low metallicities,
but to a lower extent the greater [Zn/Fe] ratios at low metallicities,
indicating eventually missing yields.


title:
The Kast Ground Based UV Spectral Survey of 79 QSOs at Redshift 2 for
  Lyman Alpha Forest and Metal Absorption

abstract:
  We present a moderate resolution (~1.15 Angstroms/pixel) survey of 79 quasars
obtained using the Kast spectrograph on the Shane 3m telescope at Lick
observatory. The spectra span the wavelength range of 3175-5880 Angstroms, and
have typical signal to noise of 6-20 in the regions of the spectra showing
Lyman alpha forest absorption. The quasars have a mean emission redshift of
z=2.17, and nearly all cover the entire Lyman alpha forest between Lyman alpha
and Lyman beta. Although the quasars were selected to avoid BAL, two quasars in
the survey are BAL, one of which is a new discovery. We list the HI and metal
ions observed in a total of 140 absorption systems. We also identify 526
emission lines, and list their observed wavelengths, along with new redshifts
of the quasars. We determine the rest wavelengths of 3 emission lines or line
blends in the forest to be 1070.95 +/- 1.00, 1123.13 +/- 0.51, and 1175.88 +/-
0.30 Angstroms.


title: Astrophysical magnetic fields and nonlinear dynamo theory

abstract:
  The current understanding of astrophysical magnetic fields is reviewed,
focusing on their generation and maintenance by turbulence. In the
astrophysical context this generation is usually explained by a self-excited
dynamo, which involves flows that can amplify a weak 'seed' magnetic field
exponentially fast. Particular emphasis is placed on the nonlinear saturation
of the dynamo. Analytic and numerical results are discussed both for small
scale dynamos, which are completely isotropic, and for large scale dynamos,
where some form of parity breaking is crucial. Central to the discussion of
large scale dynamos is the so-called alpha effect which explains the generation
of a mean field if the turbulence lacks mirror symmetry, i.e. if the flow has
kinetic helicity. Large scale dynamos produce small scale helical fields as a
waste product that quench the large scale dynamo and hence the alpha effect.
With this in mind, the microscopic theory of the alpha effect is revisited in
full detail and recent results for the loss of helical magnetic fields are
reviewed.


title: Evolution of irradiated Circumbinary Disks

abstract:
  We study the evolution and emission of circumbinary disks around close
classical T Tauri binary systems. High resolution numerical hydrodynamical
simulations are employed to model a system consisting of a central eccentric
binary star within an irradiated accretion disk. A detailed energy balance
including viscous heating, radiative cooling and irradiation from the central
star is applied to calculate accurately the emitted spectral energy
distribution. Numerical simulations using two different methods, the previously
developed Dual-Grid technique with a finite difference discretization, and the
Smoothed Particle Hydrodynamics method are employed to compare the
hydrodynamical features and strengthen our conclusions. Physical parameters of
the setup are chosen to model the close systems of DQ Tau and AK Sco. Using the
self-consistent models, we are able to fit the observed spectral energy
distributions by constraining parameters such as disk mass, density profile and
radial extension for those systems. We find that the incorporation of
irradiation effects is necessary to obtain correct disk temperatures.


title: No Planet Around HD 219542 B

abstract:
  The star HD 219542 B has been reported by us (Desidera et al. 2003) to show
low-amplitude radial velocity variations that could be due to the presence of a
Saturn-mass planetary companion or to stellar activity phenomena. In this
letter we present the results of the continuation of the radial velocity
monitoring as well as a discussion of literature determinations of the
chromospheric activity of the star (Wright et al. 2004). These new data
indicate that the observed radial velocity variations are likely related to
stellar activity. In particular, there are indications that HD 219542 B
underwent a phase of enhanced stellar activity in 2002 while the activity level
has been lower in both 2001 and 2003. Our 2003 radial velocity measurements now
deviate from our preliminary orbital solution and the peak in the power
spectrum at the proposed planet period is severely reduced by the inclusion of
the new data. We therefore dismiss the planet hypothesis as the cause of the
radial velocity variations.


title:
The K20 survey. VI. The Distribution of the Stellar Masses in Galaxies
  up to z~2

abstract:
  We present a detailed analysis of the stellar mass content of galaxies up to
z=2.5 in the K20 galaxy sample, that has a 92% spectroscopic completeness and a
complete $UBVRIzJK_s$ multicolor coverage. We find that the M/L ratio decreases
with redshift: in particular, the average M/L ratio of early type galaxies
decreases with $z$, with a scatter that is indicative of a range of
star--formation time-scales and redshift of formation. More important, the
typical M/L of massive early type galaxies is larger than that of less massive
ones, suggesting that their stellar population formed at higher z. The final
K20 galaxy sample spans a range of stellar masses from M*=10^9Msun to
M*=10^12Msun, with massive galaxies ($M*>10^11Msun) detected up to z~2. We
compute the Galaxy Stellar Mass Function at various z, of which we observe only
a mild evolution (i.e. by 20-30%) up to z~1. At z>1, the evolution of the GSMF
appears to be much faster: at z~2, about 35% of the present day stellar mass in
objects with M*~10^11Msun appear to have assembled. We also detect a change in
the physical nature of the most massive galaxies, since at z>1 a population of
massive star--forming galaxies progressively appears. We finally analyze our
results in the framework of Lambda-CDM hierarchical models. First, we show that
the large number of massive galaxies detected at high z does not violate any
fundamental Lambda-CDM constraint based on the number of massive DM halos.
Then, we compare our results with the predictions of renditions of both
semianalytic and hydro-dynamical models, that range from severe underestimates
to slight overestimates of the observed mass density at z<~2. We discuss how
the differences among these models are due to the different implementation of
the main physical processes. (Abridged)


title: An Overdensity of Extremely Red Objects Around Faint Mid-IR galaxies

abstract:
  We have searched for Extremely Red Objects (EROs) around faint mid-IR
selected galaxies in ELAIS fields. We find a significant overdensity, by
factors of 2 to 5, of these EROs compared to field EROs in the same region and
literature random field ERO counts. The excess is similar to that found
previously in the fields of known high redshift quasars and AGN. While with the
present data it cannot be definitely shown whether the overdensity is
physically connected to the mid-IR source, a derived radial distribution does
suggest this. The fraction of EROs among K-selected galaxies is high in the
mid-IR fields in agreement with the picture that the EROs responsible for the
overdensity are members of high redshift clusters of galaxies. We find R-K>5
selected EROs to be more clustered around the mid-IR galaxies than I-K>4 EROs,
though statistics are weak because of small numbers. However, this would be
consistent with a cluster/galaxy group scenario if, as we argue, the former
colour selection finds preferentially more strongly clustered early type
galaxies, whereas the latter selection includes a larger fraction of dusty
EROs. Finally, using the mid-IR data, we are able to limit the fraction of
ULIRG type very dusty EROs at K<18 magnitude to less than 10% of the total ERO
population.


title:
Cooling of neutron stars: effects of accreted envelopes, magnetic field
  and crustal superfluidity

abstract:
  We briefly review recent theoretical studies of the effects of accreted
envelopes, magnetic fields and crustal superfluidity on the cooling of neutron
stars. These effects are especially important for slowly cooling low-mass
neutron stars, where direct Urca process of neutrino emission is forbidden. The
effects are useful for interpretation of observations of several isolated
middle-aged neutron stars.


title: Searching for High Redshift Clusters

abstract:
  Distant clusters of galaxies provide a powerful method to study the formation
and evolution of galaxies, and large scale structure of the Universe. However,
the number of known clusters at high redshift (z> 0.5) is still very reduced.
As a preparatory work for detailed studies wigh GTC, we are searching for high
redshift clusters in public wide optical surveys. We will complement this with
near IR observations in 4 m telescopes. Here, we present some preliminary
results. In a field of 35 x 35 arcmin^2 we have detected 8 clusters of galaxies
at redshift z> 0.5.


title: Using the filaments in the LCRS to test the LambdaCDM model

abstract:
  It has recently been established that the filaments seen in the Las Campanas
Redshift Survey (LCRS) are statistically significant at scales as large as 70
to 80 Mpc/h in the $-3^{\circ}$ slice, and 50 to 70 Mpc/h in the five other
LCRS slices. The ability to produce such filamentary features is an important
test of any model for structure formation. We have tested the LCDM model with a
featureless, scale invariant primordial power spectrum by quantitatively
comparing the filamentarity in simulated LCRS slices with the actual data. The
filamentarity in an unbiased LCDM model, we find, is less than the LCRS.
Introducing a bias b=1.15, the model is in rough consistency with the data,
though in two of the slices the filamentarity falls below the data at a low
level of statistical significance. The filamentarity is very sensitive to the
bias parameter and a high value b=1.5, which enhances filamentarity at small
scales and suppresses it at large scales, is ruled out. A bump in the power
spectrum at k~0.05 Mpc/h is found to have no noticeable effect on the
filamentarity.


title: Formation and Evolution of Structures in the Universe

abstract:
  We summarize our work on structures in different stages of aggregation, and
spanning a wide range in redshift. We emphasize our work on high resdhift
clusters. This comprises the analysis of ~7 square degrees using deep images
with several broad-band optical filters. We plan to complement these with near
IR observations in 4 m telescopes. Preliminary results of the analysis in a
field of 35 x 35 arcmin^2 indicate the detection of several candidates to be
clusters at redshifst z> 0.5. When all the fields are analyzed, we will have an
adequate sample for future detailed studies with the GTC.


title:
Long-term optical/infrared variability in the quiescent X-ray transient
  V404 Cyg

abstract:
  We present the results of optical and infrared photometry of the quiescent
X-ray transient V404 Cyg during the period 1992-2003. The ellipsoidal
modulations extracted from the most complete databases (years 1992, 1998 and
2001) show unequal maxima and minima with relative strength varying from year
to year although their peak to peak amplitudes remain roughly constant at
0.24+-0.01 magnitudes. Fast optical variations superimposed on the secondary
star's double-humped ellipsoidal modulation were detected every year with a
mean amplitude of ~0.07 mags. We have not found significant changes in the
activity during this decade which indicates that this variability is probably
not connected to the 1989 outburst. We have found periodicities in the 1998 and
2001 data near the 6 hr quasi-periodicity observed in 1992, although we
interpret it as consequence of the appearance of a flare event almost every
night. Significant variability is also present in the I and near infrared (J
and K_short) bands and this decreases slightly or remains approximately
constant at longer wavelengths. A cross correlation analysis shows that both
the R and I emission are simultaneous down to 40 s.


title:
GRB 021211 as a Faint Analogue of GRB 990123: Exploring the Similarities
  and Differences in their Optical Afterglows

abstract:
  We present B, V, Rc, J, H, and Ks photometry of the optical afterglow of the
gamma-ray burst GRB 021211 taken at the Magellan, MMT, and WIYN observatories
between 0.7 and 50 days after the burst. We find an intrinsic spectral slope at
optical and near-infrared wavelengths of 0.69 +/- 0.14 at 0.87 days. The
optical decay during the first day is almost identical to that of GRB 990123
except that GRB 021211's optical afterglow was intrinsically approximately 38
times fainter, and the transition from the reverse shock to the forward shock
may have occurred earlier than it did for GRB 990123. We find no evidence for a
jet break or the cooling break passing through optical frequencies during the
first day after the burst. There is weak evidence for a break in the J-band
decay between 0.89 and 1.87 days which may be due to a jet. The optical and
infrared data are consistent with a relativistic fireball where the shocked
electrons are in the slow cooling regime and the electron index is 2.3 +/- 0.1.
The forward shock appears to have been expanding in a homogeneous ambient
medium during the first day after the burst. Our analysis suggests that the jet
of GRB 021211 may have a small opening angle and that the total gamma-ray
energy is likely to be much less than the canonical value of 1.33E+51 erg. If
this is the case then it is possible that most of the energy of the burst is in
another form such as a frozen magnetic field, supernova ejecta, or a second jet
component. The host galaxy of GRB 021211 is subluminous and has a star
formation rate of at least one Solar mass per year.


title:
Direct Determinations of the Redshift Behavior of the Pressure, Energy
  Density, and Equation of State of the Dark Energy and the Acceleration of the
  Universe

abstract:
  One of the goals of current cosmological studies is the determination of the
expansion and acceleration rates of the universe as functions of redshift, and
the determination of the properties of the dark energy that can explain these
observations. Here the expansion and acceleration rates are determined directly
from the data, without the need for the specification of a theory of gravity,
and without adopting an a priori parameterization of the form or redshift
evolution of the dark energy. We use the latest set of distances to SN standard
candles from Riess et al. (2004), supplemented by data on radio galaxy standard
ruler sizes, as described by Daly and Djorgovski (2003, 2004). We find that the
universe transitions from acceleration to deceleration at a redshift of about
0.4. The standard "concordance model" provides a reasonably good fit to the
dimensionless expansion rate as a function of redshift, though it fits the
dimensionless acceleration rate as a function of redshift less well. The
expansion and acceleration rates are then combined with a theory of gravity to
determine the pressure, energy density, and equation of state of the dark
energy as functions of redshift. Adopting General Relativity as the correct
theory of gravity, the redshift trends for the pressure, energy density, and
equation of state of the dark energy out to redshifts of about one are
determined, and are found to be generally consistent with the concordance
model.


title: Mass, Age, and Space Distributions of Star Clusters

abstract:
  This article reviews some recent studies of the mass, age, and space
distributions of star clusters, with a primary focus on the large population of
clusters in the interacting Antennae galaxies. Some of the highlights of these
studies are the following: 1. The mass function of the young clusters (with
ages \tau < 10^8 yr) has power-law form, dN/dM propto M^{-2}, over the observed
range of masses, 10^4 < M < 10^6 solar masses. 2. The age distribution of the
clusters declines steeply at all ages, roughly as dN/d tau propto tau^{-1} for
mass-limited samples, indicating rapid disruption of most clusters. 3. At least
20% and possibly all stars form in clusters and/or associations, including
those that are unbound and short-lived. 4. Many of the clusters that remain
bound just after their formation are disrupted on longer timescales by a
combination of mass loss by stellar evolution and several stellar dynamical
processes. 5. The young clusters have a clumpy space distribution and are
located preferentially in regions of high interstellar density, at least when
averaged over scales of about a kpc. 6. The positions of the young clusters,
however, are not correlated with the local velocity gradients or velocity
dispersions in the interstellar medium. There are growing indications that most
of these conclusions also apply to the populations of young star clusters in
other galaxies, both interacting and quiescent.


title: 128Xe and 130Xe: Testing He-shell burning in AGB stars

abstract:
  The s-process branching at 128I has been investigated on the basis of new,
precise experimental (n,g) cross sections for the s-only isotopes 128Xe and
130Xe. This branching is unique, since it is essentially determined by the
temperature- and density-sensitive stellar decay rates of 128I and only
marginally affected by the specific stellar neutron flux. For this reason it
represents an important test for He-shell burning in AGB stars. The description
of the branching by means of the complex stellar scenario reveals a significant
sensitivity to the time scales for convection during He shell flashes, thus
providing constraints for this phenomenon. The s-process ratio 128Xe/130Xe
deduced from stellar models allows for a (9+-3)% p-process contribution to
solar 128Xe, in agreement with the Xe-S component found in meteoritic presolar
SiC grains.


title: Problem of neutrino handedness in weak interactions

abstract:
  In this paper we show that the neutrino observables, including an information
about the transverse neutrino spin polarization, can be sensitive to the
effects coming from the interference terms between the standard vector V, axial
A couplings of L-handed neutrinos and exotic scalar S coupling of R-handed ones
in the differential cross section. Our analysis is based on the electron
neutrino-electron elastic scattering. This reaction is considered at the level
of the four-fermion point interaction. Neutrinos are assumed to be massive and
to be polarized Dirac fermions coming from the Sun.


title: Testing Strong-field Gravity with Quasi-Periodic Oscillations

abstract:
  The frequencies of quasi-periodic oscillations around neutron stars are
believed to be related to characteristic frequencies in the gravitational
fields of the compact objects. In different variability models, these include
the Keplerian, epicyclic, and Lense-Thirring frequencies, which depend mostly
on the properties of the stellar spacetimes. We argue that quasi-periodic
oscillations in the X-ray flux of neutron stars can be used to map the external
spacetimes of the compact objects and, therefore, lead to direct tests of
general relativity in the strong-field regime. In particular, we show that
particular extensions of General Relativity, in which the gravitational force
felt by matter is mediated by both a rank-two tensor and a scalar field, can be
constrained by current observations.


title: Millisecond Pulsar Searches and Double Neutron Star Binaries

abstract:
  A unified strategy is developed that can be used to search for millisecond
pulsars (MSPs) with ~solar mass companions (including neutron star companions
in double neutron star binaries [DNSBs]) belonging to both very short period
binaries, and those with periods so long that they could be appropriate targets
for acceleration searches, and to bridge the gap between these two extremes. In
all cases, the orbits are assumed to be circular. Applications to searches for
binary pulsars similar to PSR J0737-3039 are discussed. The most likely
candidates for more DNSBs consist of weakly magnetized neutron stars, spinning
only moderately fast, like J0737-3039A, with periods generally longer than 15
ms, though this issue is not yet settled. Because of the similarity between the
MSP components of DNSBs, and the longer period MSP population specific to
massive condensed or core collapsed globular clusters, as well as the
uncertainties about accretion-driven spinup, doubts linger about the standard
models of DNSB formation.


title: Large Scale Structure in the Local Universe: The 2MASS Galaxy Catalog

abstract:
  Using twin ground-based telescopes, the Two Micron All Sky Survey (2MASS)
scanned both equatorial hemi- spheres, detecting more than 500 million stars
and resolving more than 1.5 million galaxies in the near-infrared (1 - 2.2
microns) bands. The Extended Source "Galaxy" Catalog (XSC) embodies both
photometric and astrometric whole sky uniformity, revealing large scale
structures in the local Universe and extending our view into the Milky Way's
dust-obscured "Zone of Avoidance." The XSC represents a uniquely unbiased
sample of "normal" galaxies, particularly sensitive to the underlying,
dominant, stellar mass component of galaxies. The basic properties of the XSC,
including photometric sensitivity, source counts, and spatial distribution are
presented here. We illustrate the spatial clustering properties, ranging from
interacting galaxies to groups and clusters, and finally to the largest "cosmic
web" of superclusters spanning the sky.


title: Strong lensing by cluster-sized haloes in dark-energy cosmologies

abstract:
  We study the efficiency of numerically simulated galaxy clusters for
producing strong gravitational lensing events in different dark-energy
cosmologies with constant and time-variable equation of state and we compare it
with ``standard'' $\Lambda$CDM and OCDM models. Our main results are that: (1)
the expected abundance of gravitational arcs with large length-to-width ratio
depends on the equation of state of dark energy at the epoch of formation of
the halo; (2) as found in previous studies, the strong lensing cross section of
galaxy clusters is very sensitive to dynamical processes like mergers, whose
impact however is different for different cosmologies, being stronger for
models in which halos are less concentrated. As expected, the largest
differences in the lensing optical depth occur at moderate and high redshift.


title: Quasars as Absorption Probes of the J0053+1234 Region

abstract:
  We present UBRI photometry and spectra for 60 quasars found within one square
degree centered on the J0053+1234 region, which has been the subject of the
Caltech Faint Galaxy Redshift Survey. Candidate quasars were selected by their
ultraviolet excess with respect to the stellar locus, and confirmed
spectroscopically. The quasars span a wide range in brightness (17.5<B<21.6)
and redshift (0.43<z<2.38). These new quasars comprise a grid of absorption
probes that can be used to study large-scale structure as well as the
correlation between luminous galaxies, non-luminous halos, and Lyman-alpha
absorbers in the direction of the deep pencil-beam galaxy survey. Spectra of 14
emission line galaxies found using the same technique are also presented.


title:
Magnetic extraction of energy from accretion disc around a rotating
  black hole

abstract:
  An analytical expression for the disc power is derived based on an equivalent
circuit in black hole (BH) magnetosphere with a mapping relation between the
radial coordinate of the disc and that of unknown astrophysical load. It turns
out that this disc power is comparable with two other disc powers derived in
the Poynting flux and hydrodynamic regimes, respectively. In addition, the
relative importance of the disc power relative to the BZ power is discussed. It
is shown that the BZ power is generally dominated by the disc power except some
extreme cases. Furthermore, we show that the disc power derived in our model
can be well fitted with the jet power of M87.


title:
A Toy Model for Magnetic Extraction of Energy from Black Hole Accretion
  Disc

abstract:
  A toy model for magnetic extraction of energy from black hole (BH) accretion
disk is discussed by considering the restriction of the screw instability to
the magnetic field configuration. Three mechanisms of extracting energy
magnetically are involved. (1) The Blandford-Znajek (BZ) process is related to
the open magnetic field lines connecting the BH with the astrophysical load;
(2) the magnetic coupling (MC) process is related to the closed magnetic field
lines connecting the BH with its surrounding disk; and (3) a new scenario
(henceforth the DL process) for extracting rotational energy from the disk is
related to the open field lines connecting the disk with the astrophysical
load. The expressions for the electromagnetic powers and torques are derived by
using the equivalent circuits corresponding to the above energy mechanisms. It
turns out that the DL power is comparable with the BZ and MC powers as the BH
spin approaches unity. The radiation from a quasi-steady thin disk is discussed
in detail by applying the conservation laws of mass, energy and angular
momentum to the regions corresponding to the MC and DL processes. In addition,
the poloidal currents and the current densities in BH magnetosphere are
calculated by using the equivalent circuits.


title:
Time delay of photons of different energies in multi-dimensional
  cosmological models

abstract:
  We consider the general expressions for the time delay of photons of
different energies in the framework of multi-dimensional cosmological models.
In models with compactified extra-dimensions (Kaluza-Klein type models), the
main source of the photon time delay is the time variation of the
electromagnetic coupling, due to dimensional reduction, which induces an
energy-dependence of the speed of light. A similar relation between the fine
structure constant and the multi-dimensional gauge couplings also appears in
models with large (non-compactified) extra-dimensions. For photons of energies
around 1 TeV, propagating on cosmological distances in an expanding Universe,
the time delay could range from a few seconds in the case of Kaluza-Klein
models to a few days for models with large extra-dimensions. As a consequence
of the multi-dimensional effects, the intrinsic time profiles at the emitter
rest frame differ from the detected time profiles. The formalism developed in
the present paper allows the transformation of the predicted light curves of
various energy ranges of the emitter into the frame of the observer, for
comparison with observations. Therefore the study of energy and redshift
dependence of the time delay of photons, emitted by astrophysical sources at
cosmological distances, could discriminate between the different
multi-dimensional models and/or quantum gravity effects.


title: ISOCAM observations of the L1551 star formation region

abstract:
  The results of a deep mid-IR ISOCAM survey of the L1551 dark molecular cloud
are presented. The aim of this survey is a search for new YSO (Young Stellar
Object) candidates, using two broad-band filters centred at 6.7 and 14.3
micron. Although two regions close to the centre of L1551 had to be avoided due
to saturation problems, 96 sources were detected in total (76 sources at 6.7
micron and 44 sources at 14.3 micron). Using the 24 sources detected in both
filters, 14 were found to have intrinsic mid-IR excess at 14.3 micron and were
therefore classified as YSO candidates. Using additional observations in B, V,
I, J, H and K obtained from the ground, most candidates detected at these
wavelengths were confirmed to have mid-IR excess at 6.7 micron as well, and
three additional YSO candidates were found. Prior to this survey only three
YSOs were known in the observed region (avoiding L1551 IRS5/NE and HL/XZ Tau).
This survey reveals 15 new YSO candidates, although several of these are
uncertain due to their extended nature either in the mid-IR or in the
optical/near-IR observations. Two of the sources with mid-IR excess are
previously known YSOs, one is a brown dwarf MHO 5 and the other is the well
known T Tauri star HH30, consisting of an outflow and an optically thick disk
seen edge on.


title:
Galaxies in Present-day Clusters: Evolutionary Constraints from Their
  Distributions and Kinematics

abstract:
  We discuss evidence in local, present-day clusters of galaxies (from the
ENACS survey) about the way in which those clusters have evolved and about the
evolutionary relationships between the galaxies of different morphological
types in them. This evidence is complementary to that obtained from the study
of clusters at intermediate and high redshifts. We argue that the spatial
distribution and the kinematics of the various types of galaxies in and outside
substructures support the following picture.
  The ELLIPTICAL AND S0 GALAXIES have been around for a long time and have
obtained an isotropic velocity distribution. The spatial distribution and
kinematics of the EARLY SPIRALS are consistent with the idea that many of their
kind have transformed into an S0, but that they have survived, most likely
because of their velocities. The distribution and kinematics of the LATE
SPIRALS are consistent with a picture in which they have been accreted fairly
recently. They have mildly radial orbits and hardly populate the central
regions, most likely because they suffer tidal disruption. Finally, the
distribution and kinematics of the GALAXIES IN SUBSTRUCTURES, when taken at
face value, imply tangential velocity anisotropy for these galaxies, but this
result may be (partly) due to the procedure by which these galaxies are
selected. A first attempt to take the effects of selection into account shows
that isotropic (or even mildly radial) orbits of subcluster galaxies cannot be
excluded.


title: X-ray Detections of Two Young Bona-Fide Brown Dwarfs

abstract:
  I report here the detection of two bona-fide brown dwarfs by XMM-Newton:
[GY92] 141 in the rho-Ophiuchus star forming region and DENIS-P J155601-233809
in the Upper Scorpius OB association. The two objects have been detected with
luminosities of Lx=8.35\pm2.86*10^28 erg/s and Lx=6.54\pm1.35*10^28 erg/s
respectively, corresponding to luminosity ratios of log(Lx/Lbol)= -2.07 and
log(Lx/Lbol)= -2.69. The two sources were close to the limit of detection of
the instruments at only 2~3-sigma above the background level, and no
significant flare or variation could be detected during the 48.3ks and 33.9ks
observations. [GY92] 141 had already been observed 10 months earlier with
Chandra (see 2001 ApJ, 563, 361) with a luminosity ~14 times fainter than the
one I report here, meaning that the X-ray emission of this object is strongly
variable.


title:
A Detailed View of the Fundamental Plane of Early-Type Galaxies in
  Clusters at z~0.2

abstract:
  We present a spectroscopic sample of 48 early-type galaxies in the rich
cluster Abell 2218 and 50 galaxies in Abell 2390. Since both samples are very
similar, we combine them and investigate a total number of 98 early-type
galaxies at z~0.2. A subsample of 34 galaxies with HST structural properties is
used to construct the Fundamental Plane. Elliptical and S0 galaxies show a
zeropoint offset of m_r~0.43 mag with respect to the local Coma FP. Both
sub-samples, ellipticals and lenticulars, exhibit a similar, mild evolution and
small scatter. The moderate amount of luminosity evolution is consistent with
stellar population models of passive evolution, if z_f>=2 is assumed.


title: Evolutionary Status of Early-Type Galaxies in Distant Poor Clusters

abstract:
  We introduce our project that investigates the kinematic properties of
early-type galaxies in 6 distant poor clusters at z~0.25. This study represents
a continuation of our efforts to understand galaxy evolution in low-density
environments. Higher-resolution MOSCA spectra have been obtained at the Calar
Alto 3.5-m telescope with which we can measure absorption line strengths and
velocity dispersions. In conjunction with our HST/F702W images of all the
clusters, we are able to construct the Fundamental Plane of ellipticals and S0
galaxies in poor clusters at a look-back time of ~3 Gyrs. For galaxies outside
the HST field, we concentrate our analysis on the Mg-sigma and Faber-Jackson
relations. With the line strength diagrams age/metallicity distributions can be
derived in densities between the field and rich cluster environments. Comparing
with our rich clusters at the same cosmic epochs, the dependence of galaxy
formation models on the local environment can be tested more quantitatively.


title: The cosmic evolution of low-luminosity radio sources from the SDSS DR1

abstract:
  In this paper we constrain the evolution in the comoving space density for
low-luminosity (typically FRI) radio sources as a function of cosmic epoch by
matching deep radio surveys (WENSS, FIRST and NVSS) with the Sloan Digital Sky
Survey (SDSS). This results in 1014 matched radio sources covering an effective
area of 0.217 sr, 686 with L(325 MHz) < 10^25 W/Hz/sr, which is an order of
magnitude larger than any previous study at these luminosities. Using the
non-parametric V/Vmax test we show that low-luminosity radio sources evolve
differently to their more powerful, predominantly FRII, counterparts. Indeed,
we find that the lower luminosity population is consistent with a constant
comoving space density with redshift, as opposed to the strong positive
evolution for the more powerful sources.


title: Internal kinematics of spiral galaxies in distant rich galaxy clusters

abstract:
  We present our project on galaxy evolution in the environment of distant rich
clusters aiming at disentangling the importance of specific interaction and
galaxy transformation processes from the hierarchical evolution of field
galaxies. Spatially resolved MOS spectra were gained with VLT/FORS to analyze
the internal kinematics of disk galaxies. First results are shown for the
clusters MS 1008.1-1224 (z=0.30), Cl 0303+1706 (z=0.42), and Cl 0413-6559
(z=0.51). Out of 35 late type cluster members, 13 galaxies exhibit a rotation
curve of the universal form rising in the inner region and passing over into a
flat part. The other members have peculiar kinematics. The 13 cluster galaxies
for which a maximum rotation velocity could be derived are distributed in the
Tully-Fisher diagram very similar to field galaxies from the FORS Deep Field
with corresponding redshifts. The same is true for seven non-cluster galaxies
observed in the cluster fields. The TF-cluster spirals do not show any
significant luminosity evolution as might be expected from certain
clusterspecific phenomena. Contrary to that, the disturbed kinematics of the
non--TF cluster spirals indicate ongoing or recent interaction processes.


title: Detection of a companion to the pulsating sdB Feige 48

abstract:
  We present the discovery of a binary companion to the pulsating sdB Feige 48.
Using HST/STIS and archival FUSE spectra, we measure a period of 0.376+/-0.003
d and a velocity semi-amplitude of 28.0+/-0.2 km/s. This implies that the
companion star must either be of very low mass, or the orbit is at high
inclination. Combining 2MASS fluxes, the lack of a reflection effect, results
from asteroseismology and a measurement of the rotation velocity of Feige 48,
we show that the orbital inclination must be <= 11.4 degrees and that the
unseen companion is a white dwarf with mass >= 0.46 Msun. The implications of
this discovery, and of binarity amongst sdB pulsators, is then discussed in the
context of recent theoretical work on sdB formation. In particular we suggest
that radial velocity studies focus on sdB pulsators with no known companion,
and that asteroseismological studies of sdBs investigate a larger mass range
than previously considered in order to test formation models.


title: Another origin of cosmological redshifts

abstract:
  If gravitons are super-strong interacting particles which fulfill a flat
non-expanding universe, we would have another possibility to explain
cosmological redshifts - in a frame of non-kinematic model. It is shown by the
author that in this case SNe 1a data may be understood without any dark energy
and dark matter. A value of relaxation factor is found in this paper. In this
approach, we have Newton's law of gravity as a simplest consequence, and the
connection between Newton's and Hubble's constants. A value of the latter may
be theoretically predicted.


title: Five-Dimensional Cosmological Scaling Solution

abstract:
  A five-dimensional Ricci-flat cosmological solution is studied by assuming
that the induced 4D matter contains two components: the usual fluid for dark
matter as well as baryons and a scalar field with an exponential potential for
dark energy. With use of the phase-plane analysis it is shown that there exist
two late-time attractors one of which corresponds to a universe dominated by
the scalar field alone and the other is a scaling solution in which the energy
density of the scalar field remains proportional to that of the dark matter. It
is furthermore shown that for this 5D scaling solution the universe expands
with the same rate as in the 4D FRW models and not relies on which 4D
hypersurface the universe is located in the 5D manifold.


title: W49A North - Global or Local or No Collapse?

abstract:
  We attempt to fit observations with 5" resolution of the J=2-1 transition of
CS in the directions of H II regions A, B, and G of W49A North as well as
observations with 20" resolution of the J=2-1, 3-2, 5-4, and 7-6 transitions in
the directions of H II regions A and G by using radiative transfer
calculations. These calculations predict the intensity profiles resulting from
several spherical clouds along the line of sight. We consider three models:
global collapse of a very large (5 pc radius) cloud, localized collapse from
smaller (1 pc) clouds around individual H II regions, and multiple, static
clouds. For all three models we can find combinations of parameters that
reproduce the CS profiles reasonably well provided that the component clouds
have a core-envelope structure with a temperature gradient. Cores with high
temperature and high molecular hydrogen density are needed to match the higher
transitions (e.g. J=7-6) observed towards A and G. The lower temperature, low
density gas needed to create the inverse P-Cygni profile seen in the CS J=2-1
line (with 5" beam) towards H II region G arises from different components in
the 3 models. The infalling envelope of cloud G plus cloud B creates the
absorption in global collapse, cloud B is responsible in local collapse, and a
separate cloud, G', is needed in the case of many static clouds. The exact
nature of the velocity field in the envelopes for the case of local collapse is
not important as long as it is in the range of 1 to 5 km/s for a turbulent
velocity of about 6 km/s. High resolution observations of the J=1-0 and 5-4
transitions of CS and C34S may distinguish between these three models. Modeling
existing observations of HCO+ and C18O does not allow one to distinguish
between the three models but does indicate the existence of a bipolar outflow.


title:
On the determination of oxygen abundances in chromospherically active
  stars

abstract:
  We discuss oxygen abundances derived from [O I] 6300 and the O I triplet in
stars spanning a wide range in chromospheric activity level, and show that
these two indicators yield increasingly discrepant results with higher
chromospheric/coronal activity measures. While the forbidden and permitted
lines give fairly consistent results for solar-type disk dwarfs, spuriously
high O I triplet abundances are observed in young Hyades and Pleiades stars, as
well as in individual components of RS CVn binaries (up to 1.8 dex). The
distinct behaviour of the [O I]-based abundances which consistently remain
near-solar suggests that this phenomenon mostly results from large departures
from LTE affecting the O I triplet at high activity level that are currently
unaccounted for, but also possibly from a failure to adequately model the
atmospheres of K-type stars. These results suggest that some caution should be
exercised when interpreting oxygen abundances in active binaries or young open
cluster stars.