title:
3D Continuum radiative transfer in complex dust configurations around
  young stellar objects and active nuclei II. 3D Structure of the dense
  molecular cloud core Rho Oph D

abstract:
  Constraints on the density and thermal 3D structure of the dense molecular
cloud core Rho Oph D are derived from a detailed 3D radiative transfer
modeling. Two ISOCAM images at 7 and 15 micron are fitted simultaneously by
representing the dust distribution in the core with a series of 3D Gaussian
density profiles. Size, total density, and position of the Gaussians are
optimized by simulated annealing to obtain a 2D column density map. The
projected core density has a complex elongated pattern with two peaks. We
propose a new method to calculate an approximate temperature in an externally
illuminated complex 3D structure from a mean optical depth. This T(tau)-method
is applied to a 1.3 mm map obtained with the IRAM 30m telescope to find the
approximate 3D density and temperature distribution of the core Rho Oph D. The
spatial 3D distribution deviates strongly from spherical symmetry. The
elongated structure is in general agreement with recent gravo-turbulent
collapse calculations for molecular clouds. We discuss possible ambiguities of
the background determination procedure, errors of the maps, the accuracy of the
T(tau)-method, and the influence of the assumed dust particle sizes and
properties.


title: A Faraday Rotation Template for the Galactic Sky

abstract:
  Using a set of compilations of measurements for extragalactic radio sources
we construct all-sky maps of the Faraday Rotation produced by the Galactic
magnetic field. In order to generate the maps we treat the radio source
positions as a kind of "mask" and construct combinations of spherical harmonic
modes that are orthogonal on the masked sky. As long as relatively small
multipoles are used the resulting maps are quite stable to changes in selection
criteria for the sources, and show clearly the structure of the local Galactic
magnetic field. We also suggest the use of these maps as templates for CMB
foreground analysis, illustrating the idea with a cross-correlation analysis
between the Wilkinson Microwave Anisotropy Probe (WMAP) data and our maps. We
find a significant cross-correlation, indicating the presence of significant
residual contamination.


title: A new method of measuring the peculiar velocity power spectrum

abstract:
  We show that by directly correlating the cluster kinetic Sunyaev Zeldovich
(KSZ) flux, the cluster peculiar velocity power spectrum can be measured to
$\sim 10%$ accuracy by future large sky coverage KSZ surveys. This method is
almost free of systemics entangled in the usual velocity inversion method. The
direct correlation brings extra information of density and velocity clustering.
We utilize these information to construct two indicators of the Hubble constant
and comoving angular distance and propose a novel method to constrain
cosmology.


title:
On the extreme stationary outflows from super-star clusters: from
  superwinds to supernebulae and further massive star formation

abstract:
  The properties of star cluster winds in the supercritical, catastrophic
cooling regime are discussed. We demonstrate that strong radiative cooling may
inhibit superwinds and, after a rapid phase of accumulation of the ejected
material within the star-forming volume, a new stationary isothermal regime,
supported by the ionizing radiation from the central cluster, is established.
The expected appearance of this core/halo supernebula in the visible line
regime and possible late evolutionary tracks for super-star cluster winds, in
the absence of ionizing radiation, are thoroughly discussed.


title:
On the Generation, Propagation, and Reflection of Alfven Waves from the
  Solar Photosphere to the Distant Heliosphere

abstract:
  We present a comprehensive model of the global properties of Alfven waves in
the solar atmosphere and fast solar wind. Linear non-WKB wave transport
equations are solved from the photosphere to 4 AU, and for wave periods ranging
from 3 seconds to 3 days. We derive a radially varying power spectrum of
kinetic and magnetic energy fluctuations for waves propagating in both
directions along a superradially expanding magnetic flux tube. This work
differs from previous models in 3 major ways. (1) In the chromosphere and low
corona, the successive merging of flux tubes on granular and supergranular
scales is described using a 2D magnetostatic model of a network element. Below
a critical merging height the waves are modeled as thin-tube kink modes, and we
assume that all of the kink-mode wave energy is transformed into volume-filling
Alfven waves above the merging height. (2) The frequency spectrum of horizontal
motions is specified only at the photosphere based on prior analyses of G-band
bright point kinematics. Everywhere else the amplitudes of outward and inward
propagating waves are computed with no free parameters. We find that the wave
amplitudes in the corona agree well with off-limb nonthermal line widths. (3)
Nonlinear turbulent damping is applied to the results of the linear model using
a phenomenological loss term. A single choice for the normalization of the
turbulent outer-scale length produces both the right amount of damping at large
distances (to agree with in situ measurements) and the right amount of heating
in the extended corona (to agree with empirical wind acceleration models). In
the corona, the modeled heating rate differs by more than an order of magnitude
from a rate based on isotropic Kolmogorov turbulence.


title:
Investigating The Possible Anomaly Between Nebular and Stellar Oxygen
  Abundances in the Dwarf Irregular Galaxy WLM

abstract:
  We obtained new optical spectra of 13 H II regions in WLM with EFOSC2; oxygen
abundances are derived for nine H II regions. The temperature-sensitive [O III]
4363 emission line was measured in two bright H II regions HM7 and HM9. The
direct oxygen abundances for HM7 and HM9 are 12+log(O/H) = 7.72 +/- 0.04 and
7.91 +/- 0.04, respectively. We adopt a mean oxygen abundance of 12+log(O/H) =
7.83 +/- 0.06. This corresponds to [O/H] = -0.83 dex, or 15% of the solar
value. In H II regions where [O III] 4363 was not measured, oxygen abundances
derived with bright-line methods are in general agreement with direct values of
the oxygen abundance to an accuracy of about 0.2 dex. In general, the present
measurements show that the H II region oxygen abundances agree with previous
values in the literature. The nebular oxygen abundances are marginally
consistent with the mean stellar magnesium abundance ([Mg/H] = -0.62). However,
there is still a 0.62 dex discrepancy in oxygen abundance between the nebular
result and the A-type supergiant star WLM15 ([O/H] = -0.21). Non-zero reddening
values derived from Balmer line ratios were found in H II regions near a second
H I peak. There may be a connection between the location of the second H I
peak, regions of higher extinction, and the position of WLM15 on the eastern
side of the galaxy.


title: X-ray Insights Into Interpreting CIV Blueshifts and Optical/UV Continua

abstract:
  We present 0.5-8.0 keV Chandra observations of six bright quasars that
represent extrema in quasar emission-line properties -- three quasars each with
small and large blueshifts of the CIV emission line with respect to the
systemic redshift of the quasars. Supplemented with seven archival Chandra
observations of quasars that met our selection criteria, we investigate the
origin of this emission-line phenomenon in the general context of the structure
of quasars. We find that the quasars with the largest CIV blueshifts show
evidence, from joint-spectral fitting, for intrinsic X-ray absorption (N_H ~
10^22 cm^-2). Given the lack of accompanying CIV absorption, this gas is likely
to be highly ionized, and may be identified with the shielding gas in the
disk-wind paradigm. Furthermore, we find evidence for a correlation of
alpha_uv, the ultraviolet spectral index, with the hardness of the X-ray
continuum; an analysis of independent Bright Quasar Survey data from the
literature supports this conclusion. This result points to intrinsically red
quasars having systematically flatter hard X-ray continua without evidence for
X-ray absorption. We speculate on the origins of these correlations of X-ray
properties with both CIV blueshift and alpha_uv and discuss the implications
for models of quasar structure.


title:
Strong and weak lensing united II: the cluster mass distribution of the
  most X-ray luminous cluster RX J1347.5-1145

abstract:
  We have shown that the cluster-mass reconstruction method which combines
strong and weak gravitational lensing data, developed in the first paper in the
series, successfully reconstructs the mass distribution of a simulated cluster.
In this paper we apply the method to the ground-based high-quality multi-colour
data of RX J1347.5-1145, the most X-ray luminous cluster to date. A new
analysis of the cluster core on very deep, multi-colour data analysis of
VLT/FORS data reveals many more arc candidates than previously known for this
cluster. The combined strong and weak lensing reconstruction confirms that the
cluster is indeed very massive. If the redshift and identification of the
multiple-image system as well as the redshift estimates of the source galaxies
used for weak lensing are correct, we determine the enclosed cluster mass in a
cylinder to M(<360 h^-1 kpc)= (1.2 +/- 0.3) 10^15 Msun. In addition the
reconstructed mass distribution follows the distribution found with independent
methods (X-ray measurements, SZ). With higher resolution (e.g. HST imaging
data) more reliable multiple imaging information can be obtained and the
reconstruction can be improved to accuracies greater than what is currently
possible with weak and strong lensing techniques.


title:
Strong and weak lensing united I: the combined strong and weak lensing
  cluster mass reconstruction method

abstract:
  Weak gravitational lensing is considered to be one of the most powerful tools
to study the mass and the mass distribution of galaxy clusters. However, the
mass-sheet degeneracy transformation has limited its success. We present a
novel method for a cluster mass reconstruction which combines weak and strong
lensing information on common scales and can, as a consequence, break the
mass-sheet degeneracy. We extend the weak lensing formalism to the inner parts
of the cluster and combine it with the constraints from multiple image systems.
We demonstrate the feasibility of the method with simulations, finding an
excellent agreement between the input and reconstructed mass also on scales
within and beyond the Einstein radius. Using a single multiple image system and
photometric redshift information of the background sources used for weak and
strong lensing analysis, we find that we are effectively able to break the
mass-sheet degeneracy, therefore removing one of the main limitations on
cluster mass estimates. We conclude that with high resolution (e.g. HST)
imaging data the method can more accurately reconstruct cluster masses and
their profiles than currently existing lensing techniques.


title:
Multivariate Monte Carlo Methods for the Reflection Grating
  Spectrometers on XMM-Newton

abstract:
  We propose a novel multivariate Monte Carlo method as an efficient and
flexible approach to analyzing extended X-ray sources with the Reflection
Grating Spectrometer (RGS) on XMM Newton. A multi-dimensional interpolation
method is used to efficiently calculate the response function for the RGS in
conjunction with an arbitrary spatially-varying spectral model. Several methods
of event comparison that effectively compare the multivariate RGS data are
discussed. The use of a multi-dimensional instrument Monte Carlo also creates
many opportunities for the use of complex astrophysical Monte Carlo
calculations in diffuse X-ray spectroscopy. The methods presented here could be
generalized to other X-ray instruments as well.


title: Magnetic field generation in fully convective rotating spheres

abstract:
  Magnetohydrodynamic simulations of fully convective, rotating spheres with
volume heating near the center and cooling at the surface are presented. The
dynamo-generated magnetic field saturates at equipartition field strength near
the surface. In the interior, the field is dominated by small-scale structures,
but outside the sphere by the global scale. Azimuthal averages of the field
reveal a large-scale field of smaller amplitude also inside the star. The
internal angular velocity shows some tendency to be constant along cylinders
and is ``anti-solar'' (fastest at the poles and slowest at the equator).


title: An Iron-Rich Sun and Its Source of Energy

abstract:
  Mass-fractionation enriches light elements and the lighter isotopes of each
element at the solar surface, making a photosphere that is 91 percent H and 9
percent He. The solar interior consists mostly of elements that comprise 99
percent of ordinary meteorites (Fe, O, Ni, Si, S, Mg and Ca) elements made in
the deep interior of a supernova. Solar energy arises from a series of nuclear
reactions triggered by neutron-emission from the collapsed supernova core on
which the Sun formed. Solar mass-fractionation, solar neutrinos, and the annual
solar-wind outpouring of 3 E43 H atoms from the solar surface are by-products
of solar luminosity.


title:
Spin temperatures and covering factors for HI 21-cm absorption in damped
  Lyman-alpha systems

abstract:
  We investigate the practice of assigning high spin temperatures to damped
Lyman-alpha absorption systems (DLAs) not detected in HI 21-cm absorption. In
particular, Kanekar & Chengaulr (2003) have attributed the mix of 21-cm
detections and non-detections in low redshift (z<2.04) DLAs to a mix of spin
temperatures, while the non-detections at high redshift were attributed to high
spin temperatures. Below z=0.9, where some of the DLA host galaxy morphologies
are known, we find that 21-cm absorption is normally detected towards large
radio sources when the absorber is known to be associated with a large
intermediate (spiral) galaxy. Furthermore, at these redshifts, only one of the
six 21-cm non-detections has an optical identification and these DLAs tend to
lie along the sight-lines to the largest background radio continuum sources.
For these and many of the high redshift DLAs occulting large radio continua, we
therefore expect covering factors of less than the assumed/estimated value of
unity. This would have the effect of introducing a range of spin temperatures
considerably narrower than the current range of >9000 K, while still supporting
the hypothesis that the high redshift DLA sample comprises a larger proportion
of compact galaxies than the low redshift sample.


title:
Surface Compositions of R Coronae Borealis Stars and Extreme Helium
  Stars - Some Connections

abstract:
  Abundances of R Coronae Borealis stars (RCBs) and Extreme Helium stars (EHes)
are discussed. Recent estimates of the $s$-process elements in hot extreme
helium stars show enhancements of lighter $s$-process elements (Y, Zr) relative
to heavier $s$-process elements, a characteristic shared by RCB stars. It also
suggests that atleast some EHe stars went through an episode of $s$-process
element synthesis in their earlier evolution. A majority of RCB stars show a
high $^{12}$C/$^{13}$C ratio in their atmospheres. A recent analysis of the
spectrum of minority RCB star V CrA, however, shows a lower value between 4 $-$
10. The implications of these results are discussed.


title:
Century scale persistence in longitude distribution: in the Sun and in
  silico

abstract:
  Using Greenwich sunspot data for 120 years it was recently observed that
activity regions on the Sun's surface tend to lie along smoothly changing
longitude strips 180 degrees apart from each other. However, numerical
experiments with random input data show that most, if not all, of the observed
longitude discrimination can be looked upon as an artifact of the analysis
method.


title: Propagation and Signatures of Ultra High Energy Cosmic Rays

abstract:
  We study the extragalactic protons with universal spectrum, which is
independent of mode of propagation, when distance between sources is less than
the propagation lengths, such as energy attenuation length or diffusion length
(for propagation in magnetic fields). The propagation features in this
spectrum, the GZK cutoff, dip and bump, are studied with help of modification
factor, which weakly depends on the generation spectrum index $\gamma_g$. We
argue that from the above features the dip is the most model-independent one.
For the power-law generation spectrum with $\gamma_g=2.7$ the dip is very well
confirmed by the data of all existing detectors, which gives the strong
evidence for extragalactic protons propagating through CMB. We develop the AGN
model for origin of UHECR, which successfully explains the observed spectra up
to $1\times 10^{20}$ eV and transition from galactic to extragalactic cosmic
rays. The calculated spectrum has the GZK cutoff, and the AGASA excess of
events at $E \gsim 1\times 10^{20}$ eV needs another component, e.g. from
superheavy dark matter. In case of weak extragalactic magnetic fields this
model is consistent with small-angle clustering and observed correlation with
BL Lacs.


title:
Supernova Neutrino Process and its Impact on the Galactic Chemical
  Evolution of the Light Elements

abstract:
  In order to resolve the overproduction problem of 11B in supernova explosions
during Galactic chemical evolution, the dependence of the ejected masses of the
light elements produced through the nu-process in supernova explosions on
supernova neutrino parameters is investigated and constraints on the supernova
neutrinos are evaluated. Detailed nucleosynthesis in a supernova explosion
model corresponding to SN 1987A is calculated by postprocessing. The ejected
masses of 11B and 7Li depend strongly on the temperature of mu- and
tau-neutrinos and their antiparticles and are roughly proportional to the total
neutrino energy. The range of temperature of mu- and -tau neutrinos and their
antiparticles appropriate for the amount of 11B necessary for Galactic chemical
evolution and the total neutrino energy deduced from the gravitational energy
of a typical neutron star is between 4.8 MeV and 6.6 MeV. In the case of
neutrino energy spectra with non-zero chemical potential, this range decreases
by about 10%.


title: Low-mass bare strange stars

abstract:
  Strange stars with low masses are suggested to exist in reality, the origin
of which could be via accretion-induced collapse (AIC) of white dwarfs. Such a
strange star is likely bare, and would thus spin very fast, even to a period of
< 0.1 ms. Strange stars with low masses may differ from those with solar-masses
in various astrophysical appearances. Observations to test this ``low-mass''
idea are proposed.


title:
Molecular abundance ratios as a tracer of accelerated collapse in
  regions of high mass star formation?

abstract:
  Recent observations suggest that the behaviour of tracer species such as
N_2H+ and CS is significantly different in regions of high and low mass star
formation. In the latter, N_2H+ is a good tracer of mass, while CS is not.
Observations show the reverse to be true in high-mass star formation regions.
We use a computational chemical model to show that the abundances of these and
other species may be significantly altered by a period of accelerated collapse
in high mass star forming regions. We suggest these results provide a potential
explanation of the observations, and make predictions for the behaviour of
other species.


title: Cosmological Evolution of a Quintom Model of Dark Energy

abstract:
  We investigate in this paper the cosmological evolution of a dark energy
model with two scalar fields where one of the scalar has canonical kinetic
energy and another scalar has negative kinetic energy term. For such a system
with exponential potentials we find that during the evolution of the universe
the equation of state $w$ changes from $w>-1$ to $w<-1$, which is consistent
with the recent observations. A phase-plane analysis shows that the
"phantom"-dominated scaling solution is the stable late-time attractor of this
type of models.


title:
Study of the Galactic Interstellar Medium from High Resolution X-Ray
  Spectroscopy: X-Ray Absorption Fine Structure and Abundances of O, Mg, Si, S,
  and Fe

abstract:
  We study the composition of the Galactic interstellar medium (ISM) toward the
Galactic center region (5 < |l| < 20 degree) by utilizing X-ray absorption
features of three bright low-mass X-ray binaries (LMXBs), GX 13+1, GX 5-1, and
GX 340+0, observed with the Chandra HETGS. We detect X-ray absorption fine
structure (XAFS) of the Si K-edge, characterized by a narrow and a broad
absorption feature at 1846 and ~1865 eV, respectively. Comparison with ground
experimental data indicates that most of the ISM Si exists in the form of
silicates, although a composition of "pure" forsterite is ruled out. The XAFS
spectra of the sulfur K-edge indicate that a significant fraction of S exists
in the gas phase. From each source, we derive the column densities of Mg, S,
Si, and Fe from the K-edge depth and that of O (or H) from the absorption of
the continuum. The elemental abundance ratios are found to be consistent
between the three targets: the mean values of O/Si, Mg/Si, S/Si, and Fe/Si are
determined to be 0.55+-0.17, 1.14+-0.13, 1.03+-0.12, and 0.97+-0.31 solar,
respectively (90% error in the mean value). We discuss the origins of the
overabundances of the heavy metals relative to O in the Galactic ISM by
comparison with the abundance pattern of the intracluster medium in clusters of
galaxies. Assuming that most of the Mg and Si atoms are depleted into silicates
of either the proxine or olivine family, we estimate that the number ratio of
Mg to Fe in olivine is >~1.2 and that 17%-43% of the total O atoms in the ISM
must be contained in silicate grains.


title:
Loop length and magnetic field estimates from oscillations detected
  during an X-ray flare on AT Mic

abstract:
  We analyse oscillations observed in the X-ray light curve of the late-type
star AT Mic. The oscillations occurred during flare maximum. We interpret these
oscillations as density perturbations in the flare loop. Applying various
models derived for the Sun, the loop length and the magnetic field of the flare
can be estimated. We find a period of 740 s, and that the models give similar
results (within a factor of 2) for the loop length (~5.4e10 cm) and the
magnetic field (~100 G). For the first time, an oscillation of a stellar X-ray
flare has been observed and results thus obtained for otherwise unobservable
physical parameters.


title: Detection of the linear radical HC4N in IRC+10216

abstract:
  We report the detection of the linear radical HC4N in the C-rich envelope of
IRC+10216. After HCCN, HC4N is the second member of the allenic chain family
HC_(2n)N observed in space. The column density of HC4N is found to be 1.5
10**12 cm**(-2). The abundance ratio HC2N/HC4N is 9, a factor of two larger
than the decrement observed for the cyanopolyynes HC$_(2n+1)N/HC_(2n+3)N.
Linear HC_4N has a 3-Sigma electronic ground state and is one of the 3
low-energy isomeric forms of this molecule. We have searched for the bent and
ringed HC4N isomers, but could only derive an upper limit to their column
densities of about 3 10**(12) cm**(-2).


title: Structures in a class of magnetized scale-free discs

abstract:
  We construct analytically stationary global configurations for both aligned
and logarithmic spiral coplanar magnetohydrodynamic (MHD) perturbations in an
axisymmetric background MHD disc with a power-law surface mass density
$\Sigma_0\propto r^{-\alpha}$, a coplanar azimuthal magnetic field $B_0\propto
r^{-\gamma}$, a consistent self-gravity and a power-law rotation curve
$v_0\propto r^{-\beta}$ where $v_0$ is the linear azimuthal gas rotation speed.
The barotropic equation of state $\Pi\propto\Sigma^{n}$ is adopted for both MHD
background equilibrium and coplanar MHD perturbations where $\Pi$ is the
vertically integrated pressure and $n$ is the barotropic index. For a
scale-free background MHD equilibrium, a relation exists among $\alpha$,
$\beta$, $\gamma$ and $n$ such that only one parameter (e.g., $\beta$) is
independent. For a linear axisymmetric stability analysis, we provide global
criteria in various parameter regimes. For nonaxisymmetric aligned and
logarithmic spiral cases, two branches of perturbation modes (i.e., fast and
slow MHD density waves) can be derived once $\beta$ is specified. To complement
the magnetized singular isothermal disc (MSID) analysis of Lou, we extend the
analysis to a wider range of $-1/4<\beta<1/2$. As an example of illustration,
we discuss specifically the $\beta=1/4$ case when the background magnetic field
is force-free. Angular momentum conservation for coplanar MHD perturbations and
other relevant aspects of our approach are discussed.


title: Statistical Analysis of Extra-galactic Rotation Measures

abstract:
  We have performed a statistical analysis of a sample of 1100 extra-galactic
rotation measures (RMs) obtained from the literature. Using a subsample of
approximately 800 reliable RMs we compute a rotation measure sky and determine
reliable large scale features for the line of sight Galactic magnetic field. We
find that the influence of the Milky Way can be seen up to roughly 30 degrees
on either side of the Galactic plane. Furthermore we observe an excess of RM on
spatial scales between 30 degrees and 50 degrees in the region of the Galactic
Plane. Additionally, the support for a bisymmetric spiral Galactic magnetic
field is significantly reduced in our analysis.


title:
Covariant analysis of Newtonian multi-fluid models for neutron stars:
  III Transvective, viscous, and superfluid drag dissipation

abstract:
  As a follow up to articles dealing firstly with a convective variational
formulation in a Milne-Cartan framework for non-dissipative multi fluid models,
and secondly with various ensuing stress energy conservation laws and
generalised virial theorems, this work continues a series showing how
analytical procedures developed in the context of General Relativity can be
usefully adapted for implementation in a purely Newtonian framework where they
provide physical insights that are not so easy to obtain by the traditional
approach based on a 3+1 space time decomposition. The present article describes
the 4-dimensionally covariant treatment of various dissipative mechanisms,
including viscosity in non-superfluid constituents, superfluid vortex drag,
ordinary resistivity (mutual friction) between relatively moving non-superfluid
constituents, and the transvective dissipation that occurs when matter is
transformed from one constituent to another due to chemical disequilibrium such
as may be produced by meridional circulation in neutron stars. The
corresponding non dissipative limit cases of vortex pinning, convection, and
chemical equilibrium are also considered.


title: Some constraints on brane inflation models with power-law potentials

abstract:
  We investigate inflation in Randall-Sundrum type II brane scenario with
closed Friedman-Robertson-Walker (FRW) brane. We consider only power-law
potentials of the scalar field and wide range of powers and parameters for
them. For our models we numerically calculate the total number of e-folds, the
value of potential at the end of inflation and amplitude and spectral index of
scalar perturbations at the epoch when the present Hubble scale leaves the
horizon. All these values we calculate for different initial conditions and
different values of parameters. Then we compare our theoretical predictions
with observation data and set constraints on the parameters of our model.


title:
The Maximum Energy and Spectra of Cosmic Rays Accelerated in Active
  Galactic Nuclei

abstract:
  We computed the energy spectra of the incident (on an air shower array)
ultrahigh-energy (E > 4x10^19 eV) cosmic rays (CRs) that were accelerated in
nearby Seyfert nuclei at redshifts z<= 0.0092 and in BL Lac objects. For our
calculations, we took the distribution of these sources over the sky from
catalogs of active galactic nuclei. In accordance with the possible particle
acceleration mechanisms, the initial CR spectrum was assumed to be
monoenergetic for BL Lac's and a power law for Seyfert nuclei. The CR energy
losses in intergalactic space were computed by the Monte Carlo method. The
artificial proton statistic was 10^5 for each case considered. The computed
spectra of the particles incident on an air shower array agree with the
measurements, which indirectly confirms the adopted acceleration models. At
energies E>=10^20 eV, the spectrum of the protons from nearby Seyfert nuclei
that reached an air shower array closely matches the spectrum of the particles
from BL Lac's. BL Lac's are, on average, several hundred Mpc away. Therefore,
it is hard to tell whether a blackbody cutoff exists or not by analyzing the
shape of the measured spectrum at E>= 5x10^19 eV.


title: High Frequency Peakers: young radio sources or flaring blazars?

abstract:
  We present new, simultaneous, multifrequency observations of 45 out of the 55
candidate High Frequency Peakers (HFP) selected by Dallacasa et al. (2000),
carried out 3 to 4 years after a first set of observations. Our sub-sample
consists of 10 galaxies, 28 stellar objects (``quasars'') and 7 unidentified
sources. Both sets of observations are sensitive enough to allow the detection
of variability at the 10% level or lower. While galaxies do not show
significant variability, most quasars do. Seven of them no longer show the
convex spectrum which is the defining property of Gigahertz Peaked Spectrum
(GPS)/HFP sources and are interpreted as blazars caught by Dallacasa et al.
(2000) during a flare, when a highly self-absorbed component dominated the
emission. In general, the variability properties (amplitude, timescales,
correlation between peak luminosity and peak frequency of the flaring
component) of the quasar sub-sample resemble those of blazars. We thus conclude
that most HFP candidates identified with quasars may well be flaring blazars.


title: Thermal radiation from magnetic neutron star surfaces

abstract:
  We investigate the thermal emission from magnetic neutron star surfaces in
which the cohesive effects of the magnetic field have produced the condensation
of the atmosphere and the external layers. This may happen for sufficiently
cool atmospheres with moderately intense magnetic fields. The thermal emission
from an isothermal bare surface of a neutron star shows no remarkable spectral
features, but it is significantly depressed at energies below some threshold
energy. However, since the thermal conductivity is very different in the normal
and parallel directions to the magnetic field lines, the presence of the
magnetic field is expected to produce a highly anisotropic temperature
distribution, depending on the magnetic field geometry. In this case, the
observed flux of such an object looks very similar to a BB spectrum, but
depressed in a nearly constant factor at all energies. This results in a
systematic underestimation of the area of the emitter (and therefore its size)
by a factor 5-10 (2-3).


title: The Zeeman-sensitive emission lines of Mg I at 12 micron in Procyon

abstract:
  Emission-lines of magnesium at 12 microns have been observed in the spectrum
of Procyon. We reproduce the observed, disk-averaged line flux from Procyon (as
well as the observed intensity profiles from the Sun) by calculating the line
formation, relaxing the assumption of Local Thermodynamic Equilibrium. We find
that the lines in Procyon are formed in the photosphere in the same manner as
the solar lines. We discuss our modeling of these Rydberg lines and evaluate,
among other things, the importance of the ionizing flux and updated model-atom
parameters. The lines are of large diagnostic value for measurements of stellar
magnetic-fields through their Zeeman splitting. We have not, however, detected
splitting of the MgI lines in Procyon. Using simple arguments, we believe we
would have detected a magnetic field, had it been of a strength larger than
approximately 800 Gauss covering more than a quarter of the surface. We discuss
the prospects for future use of the Zeeman-sensitive, mid-infrared, MgI
emission lines as a diagnostic tool for stellar magnetic fields.


title: Cosmic abundances: The impact of stellar duplicity

abstract:
  The mass-transfer scenario links chemical peculiarities with stellar
duplicity for an increasing number of stellar classes (classical and dwarf
barium stars, subgiant and giant CH stars, S stars without technetium, yellow
symbiotic stars, WIRRING stars, Abell-35-like nuclei of planetary nebulae...).
Despite these successes, the mass-transfer scenario still faces several
problems: What is the mass-transfer mode? Why orbital elements of dwarf barium
stars do not fully match those of the classical barium stars? What is the
origin of the few non-binary stars among dwarf barium stars? The paper reviews
these open questions.


title:
A far infrared view of the Lockman Hole from ISO 95 micron observations
  - II. Optical identifications and insights into the nature of the
  far-infrared sources

abstract:
  We present the optical identifications of a 95 micron ISOPHOT sample in the
Lockman Hole over an area of about half square degree. The catalogue
(Rodighiero et al. 2003) includes 36 sources, making up a complete flux-limited
sample for fluxes > 100 mJy. Reliable sources were detected, with decreasing
but well-controlled completeness, down to 20 mJy. We have combined mid-IR and
radio catalogues in this area to identify the potential optical counterparts of
the far-IR sources. We found 14 radio and 13 15 micron associations, 10 of
which have both associations. For the 11 sources with spectroscopic redshift,
we have performed a spectrophotometric analysis of the observed Spectral Energy
Distributions. Four of these 95 micron sources have been classified as faint IR
galaxies (L_FIR<1.e11 solar luminosity), six as LIRGs and only one ULIRG. We
have discussed the redshift distribution of these objects, comparing our
results with evolutionary model predictions 95 and 175 micron. Given their
moderate distances (the bulk of the closest spectroscopically identified
objects lying at z<0.2), their luminosities and star formation rates (median
value 10 solar masses/yr), the sources unveiled by ISOPHOT at 95 micron seem to
correspond to the low redshift (z<0.3) FIRBACK 175 micron population, composed
of dusty, star-forming galaxies with moderate star formation rates. We computed
and compared different SFR estimators, and found that the SF derived from the
bolometric IR luminosity is well correlated with that computed from the radio
and mid-IR fluxes.


title: The Supernovae Associated with Gamma-Ray Bursts

abstract:
  Supernovae (SNe) were long suspected as possible progenitors of gamma-ray
bursts (GRBs). The arguments relied on circumstantial evidence. Several recent
GRBs, notably GRB 030329, have provided direct, spectroscopic evidence that SNe
and GRBs are related. The SNe associated with GRBs are all of Type Ic, implying
a compact progenitor, which has implications for GRB models. Other peculiar
Type Ic SNe may help to expand understanding of the mechanisms involved.


title:
Chandra-SDSS Normal and Star-Forming Galaxies I: X-ray Source Properties
  of Galaxies Detected by Chandra in SDSS DR2

abstract:
  We have cross-correlated X-ray catalogs derived from archival Chandra ACIS
observations with a Sloan Digital Sky Survey (SDSS) Data Release 2 (DR2) galaxy
catalog to form a sample of 42 serendipitously X-ray detected galaxies over the
redshift interval 0.03 < z < 0.25. This pilot study will help fill in the
"redshift gap" between local X-ray-studied samples of normal galaxies and those
in the deepest X-ray surveys. Our chief purpose is to compare optical
spectroscopic diagnostics of activity (both star-formation and accretion) with
X-ray properties of galaxies. Our work supports a normalization value of the
X-ray-star-formation-rate (X-ray-SFR) correlation consistent with the lower
values published in the literature. The difference is in the allocation of
X-ray emission to high-mass X-ray binaries relative to other components such as
hot gas, low-mass X-ray binaries, and/or AGN. We are able to quantify a few
pitfalls in the use of lower-resolution, lower signal-to-noise optical
spectroscopy to identify X-ray sources (as has necessarily been employed for
many X-ray surveys). Notably, we find a few AGN that likely would have been
misidentified as non-AGN sources in higher-redshift studies. However, we do not
find any X-ray hard, highly X-ray-luminous galaxies lacking optical
spectroscopic diagnostics of AGN activity. Such sources are members of the
"X-ray Bright, Optically Normal Galaxy" (XBONG) class of AGN.


title:
Evolution of the Cluster Mass and Correlation Functions in LCDM
  Cosmology

abstract:
  The evolution of the cluster mass function and the cluster correlation
function from z = 0 to z = 3 are determined using 10^6 clusters obtained from
high-resolution simulations of the current best-fit LCDM cosmology (\Omega_m =
0.27, \sigma_8 = 0.84, h = 0.7). The results provide predictions for
comparisons with future observations of high redshift clusters. A comparison of
the predicted mass function of low redshift clusters with observations from
early Sloan Digital Sky Survey data, and the predicted abundance of massive
distant clusters with observational results, favor a slightly larger amplitude
of mass fluctuations (\sigma_8 = 0.9) and lower density parameter (\Omega_m =
0.2); these values are consistent within 1-\sigma with the current
observational and model uncertainties. The cluster correlation function
strength increases with redshift for a given mass limit; the clusters were more
strongly correlated in the past, due to their increasing bias with redshift -
the bias reaches b = 100 at z = 2 for M > 5 x 10^13 h^-1 M_sun. The
richness-dependent cluster correlation function, represented by the correlation
scale versus cluster mean separation relation, R0-d, is generally consistent
with observations. This relation can be approximated as R_0 = 1.7 d^0.6 h^-1
Mpc for d = 20 - 60 h^-1 Mpc. The R0-d relation exhibits surprisingly little
evolution with redshift for z < 2; this can provide a new test of the current
LCDM model when compared with future observations of high redshift clusters.


title:
Evidence for an Intermediate-Mass Black Hole: Chandra and XMM-Newton
  Observations of the Ultraluminous Supersoft X-ray Source in M101 during its
  2004 Outburst

abstract:
  We report the results of Chandra and XMM-Newton observations of a new
outburst of an ultraluminous supersoft X-ray source in M101. CXOU
J140332.3+542103 was observed in a low luminosity state (L_x~1e37 erg/s)
between 2004 January and May. The low-state X-ray spectra were relatively hard;
the combined low state spectrum can be fitted with a combination of a power-law
with photon index of 1.4 and a blackbody of 63 eV. During 2004 July, the source
underwent a strong outburst and the peak 0.3-7 keV luminosity reached 3e40
erg/s, with a bolometric luminosity of about 1e41 erg/s. The outburst spectra
were very soft and can generally be fitted with a blackbody model with
temperatures of 50-100 eV. In two of the observations, absorption edges at 0.33
keV, 0.56 keV, 0.66 keV, and 0.88 keV were found. An XMM-Newton observation was
also performed during the decay of the outburst, and a power-law tail was seen
in addition to the supersoft spectrum. We consider different accretion models;
one involving an intermediate-mass black hole can explain the observations.


title: Rotation Velocities of Two Low Luminosity Field Galaxies

abstract:
  We present H-alpha rotation curves of two low luminosity field galaxies with
r-band absolute magnitudes M_r=-13.9^{+0.8}_{-0.5} and M_r=-14.7^{+0.3}_{-0.2}
(for h=0.7; the large error bars reflect distance uncertainties). Most
previously studied galaxies in this luminosity range are members of groups
defined by brighter galaxies, but these two systems, selected from Blanton et
al.'s (2004) sample of low luminosity galaxies in the Sloan Digital Sky Survey
(SDSS), appear to have no bright companions. The measured rotation speeds at
the outer extent of the H-alpha rotation curves, 34.8+/-3.8 km/s and 30.9+/-7.2
km/s, are larger than the values of 16.0^{+6.1}_{-5.4} km/s and
20.9^{+6.2}_{-5.2} km/s predicted by extrapolating the inverse Tully-Fisher
relation of luminous SDSS galaxies to these faint luminosities. However, a
previous HI measurement of the first galaxy shows that it has a gas mass
similar to its stellar mass, and the total baryonic mass is consistent with
that predicted by McGaugh et al.'s (2000) "baryonic Tully-Fisher relation." We
find r-band dynamical mass-to-light ratios within the radii of the last H-alpha
data points (about 1.8 disk scale lengths in each case) of 12.6^{+4.7}_{-4.5}
Msun/Lsun and 4.8^{+2.5}_{-2.1} Msun/Lsun, much higher than the values ~ 1
Msun/Lsun expected for the stellar populations. The dynamical properties of
these galaxies, including the rotation speeds and evidence for high gas
fractions and dark matter domination within the luminous extent of the galaxy,
are consistent with those of previously studied faint galaxies in nearby
groups. Further studies of the SDSS sample will allow characterization of low
luminosity galaxies over the full range of environments in which they reside.


title: The binary progenitor of Tycho Brahe's 1572 supernova

abstract:
  The brightness of type Ia supernovae, and their homogeneity as a class, makes
them powerful tools in cosmology, yet little is known about the progenitor
systems of these explosions. They are thought to arise when a white dwarf
accretes matter from a companion star, is compressed and undergoes a
thermonuclear explosion Unless the companion star is another white dwarf (in
which case it should be destroyed by the mass-transfer process itself), it
should survive and show distinguishing properties. Tycho's supernova is one of
the only two type Ia supernovae observed in our Galaxy, and so provides an
opportunity to address observationally the identification of the surviving
companion. Here we report a survey of the central region of its remnant, around
the position of the explosion, which excludes red giants as the mass donor of
the exploding white dwarf. We found a type G0--G2 star, similar to our Sun in
surface temperature and luminosity (but lower surface gravity), moving at more
than three times the mean velocity of the stars at that distance, which appears
to be the surviving companion of the supernova.


title: Hubble's View of Transiting Planets

abstract:
  The Hubble Space Telescope is uniquely able to study planets that are
observed to transit their parent stars. The extremely stable platform afforded
by an orbiting spacecraft, free from the contaminating effects of the Earth's
atmosphere, enables HST to conduct ultra-high precision photometry and
spectroscopy of known transiting extrasolar planet systems. Among HST's list of
successful observations of the first such system, HD 209458, are (1) the first
detection of the atmosphere of an extrasolar planet, (2) the determination that
gas is escaping from the planet, and (3) a search for Earth-sized satellites
and circumplanetary rings. Numerous wide-field, ground-based transit surveys
are poised to uncover a gaggle of new worlds for which HST may undertake
similar studies, such as the newly-discovered planet TrES-1. With regard to the
future of Hubble, it must be noted that it is the only observatory in existence
capable of confirming transits of Earth-like planets that may be detected by
NASA's Kepler mission. Kepler could reveal Earth-like transits by the year
2010, but without a servicing mission it is very unlikely that HST would still
be in operation.


title: The Ionized Component of Intermediate-Velocity Cloud Complex L

abstract:
  We present the first full map of the H-alpha emission from the
intermediate-velocity cloud Complex L. Kinematically resolved emission
components from the ionized gas reveal a close spatial and velocity
correspondence to that of the neutral gas as mapped by 21 cm line observations.
Using a simple Gaussian component fitting technique, we compare the details of
the emission from the two phases of Complex L. The mean velocity of the H-alpha
and 21 cm emission are strongly correlated, but we find that the some of the
ionized gas is systematically offset ~ -4 km/s relative to the neutral gas.
Line widths are qualitatively comparable, but both emission components are too
low signal-to-noise to study any differences between the phases. Finally, as
with our previous study toward Complex K, we find I(H-alpha) is not strongly
correlated to N(H I) along the same lines of sight through Complex L.


title:
Multi-density model of the ionised gas in NGC 253 using radio
  recombination lines

abstract:
  We have imaged the H92alpha (8.3 GHz), H75alpha (15 GHz), and H166alpha (1.4
GHz) Radio Recombination Lines (RRLs) from NGC 253 at resolutions of 4.5 pc
(0.4"), 2.5 pc (0.2") and 53 pc (4.5") respectively. The H92alpha line arises
from individual compact sources, most of which possess radio continuum
counterparts. The line widths range from ~200 km/s for the sources near the
radio nucleus to 70-100 km/s for the extranuclear ones. These lines are emitted
by gas at a density ~10000 /cc. The remainder of the cm-wave RRLs arise in
lower density gas (~500 /cc) with a higher area filling factor and with ten
times highermass. A third component of higher density gas (>10000 /cc) is
required to explain the mm-wave RRLs.


title:
High Resolution Mid - Infrared Imaging of the AGB Star RV Boo with the
  Steward Observatory Adaptive Optics System

abstract:
  We present high resolution (~0.1"), very high Strehl ratio (0.97+-0.03)
mid-infrared (IR) adaptive optics (AO) images of the AGB star RV Boo utilizing
the MMT adaptive secondary AO system. RV Boo was observed at a number of
wavelengths over two epochs (9.8 um in May 2003, 8.8, 9.8 and 11.7 um in
February 2004) and appeared slightly extended at all wavelengths. While the
extension is very slight at 8.8 and 11.7 um data, the extension is somewhat
more pronounced at 9.8 um. With such high Strehls we can achieve
super-resolutions of 0.1" by deconvolving RV Boo with a point-spread function
(PSF) derived from an unresolved star. We tentatively resolve RV Boo into a
0.16" FWHM extension at a position angle of 120 degrees. At a distance of
390(+250)(-100) pc, this corresponds to a FWHM of 60(+40)(-15) AU. We measure a
total flux at 9.8 um of 145+-24 Jy for the disk and star. Based on a dust
thermal emission model for the observed IR spectral energy distribution and the
9.8 um AO image, we derive a disk dust mass of 1.6x10^-6 Msun and an
inclination of 30 to 45 degrees from edge-on. We discuss whether the dust disk
observed around RV Boo is an example of the early stages in the formation of
asymmetric structure in planetary nebula.


title: S Ori 70: still a strong cluster planet candidate

abstract:
  In this paper I show that the coolest $\sigma$Orionis cluster planet S Ori 70
is still a strong candidate member despite recent claims by Burgasser et al.
that it could be a brown dwarf interloper. The main point of my argument is
that the colors of S Ori 70 are significantly different to those of field
dwarfs. This object has in fact the reddest $H-K$ color of all known T dwarfs,
a clear indication of low gravity according to all published models. In a $J-H$
versus $H-K$ diagram, S Ori 70 lies in the region where models of ultracool
dwarfs predict that low gravity objects should be located. I conclude that S
Ori 70 is still a strong candidate member of the $\sigma$Orionis open cluster.
I briefly discuss additional observational tests that can be carried out with
existing facilities to verify the $\sigma$Orionis membership of this cluster
planet candidate.


title:
The Age-Dependence of the Detectabiity of Comets Orbiting Solar-Type
  Stars

abstract:
  The outflows from comets in orbit around G-type main-sequence stars can be
detected when they produce transient OH absorption lines in the spectrum near
3100 Angstroms of the host star. There is only about a 3 X 10^{-8} probability
of detecting an analog to comet Hale-Bopp orbiting an analog to the Sun.
However, for young solar-type stars with very large numbers of comets, possibly
delivering water to terrestrial planets, there is as much as a 1% chance that
any sufficiently sensitive, randomly-timed observation may detect such
transient absorption.


title: Crossing the Phantom Divide: Dark Energy Internal Degrees of Freedom

abstract:
  Dark energy constraints have forced viable alternatives that differ
substantially from a cosmological constant Lambda to have an equation of state
w that evolves across the phantom divide set by Lambda. Naively, crossing this
divide makes the dark energy gravitationally unstable, a problem that is
typically finessed by unphysically ignoring the perturbations. While this
procedure does not affect constraints near the favored cosmological constant
model it can artificially enhance the confidence with which alternate models
are rejected. Similar to the general problem of stability for w< 0, the
solution lies in the internal degrees of freedom in the dark energy sector. We
explicitly show how to construct a two scalar field model that crosses the
phantom divide and mimics the single field behavior on either side to
substantially better than 1% in all observables. It is representative of models
where the internal degrees of freedom keep the dark energy smooth out to the
horizon scale independently of the equation of state.


title:
Line formation in solar granulation VI. [C I], C I, CH and C2 lines and
  the photospheric C abundance

abstract:
  The solar photospheric carbon abundance has been determined from [C I], C I,
CH vibration-rotation, CH A-X electronic and C2 Swan electronic lines by means
of a time-dependent, 3D, hydrodynamical model of the solar atmosphere.
Departures from LTE have been considered for the C I lines. These turned out to
be of increasing importance for stronger lines and are crucial to remove a
trend in LTE abundances with the strengths of the lines. Very gratifying
agreement is found among all the atomic and molecular abundance diagnostics in
spite of their widely different line formation sensitivities. The mean of the
solar carbon abundance based on the four primary abundance indicators ([C I], C
I, CH vibration-rotation, C_2 Swan) is log C = 8.39 +/- 0.05, including our
best estimate of possible systematic errors. Consistent results also come from
the CH electronic lines, which we have relegated to a supporting role due to
their sensitivity to the line broadening. The new 3D based solar C abundance is
significantly lower than previously estimated in studies using 1D model
atmospheres.


title: Structure of the electrospheres of bare strange stars

abstract:
  We consider a thin ($\sim 10^2-10^3$ fm) layer of electrons (the
electrosphere) at the quark surface of a bare strange star, taking into account
the surface effects at the boundary with the vacuum. The quark surface holds
the electron layer by an extremely strong electric field, generated in the
electrosphere to prevent the electrons from escaping to infinity by
counterbalancing the degeneracy and thermal pressure. Because of the surface
tension and depletion of $s$ quarks a very thin (a few fm) charged layer of
quarks forms at the surface of the star. The formation of this layer modifies
the structure of the electrosphere, by significantly changing the electric
field and the density of the electrons, in comparison with the case when the
surface effects are ignored. Some consequences of the modification of the
electrosphere structure on the properties of strange stars are briefly
discussed.


title: A 4.8- and 8.6-GHz Survey of the Large Magellanic Cloud: I The Images

abstract:
  Detailed 4.8- and 8.6-GHz radio images of the entire Large Magellanic Cloud
with half-power beamwidths of 33" at 4.8 GHz and 20" at 8.6 GHz have been
obtained using the Australia Telescope Compact Array. A total of 7085 mosaic
positions were used to cover an area of 6 degrees on a side. Full polarimetric
observations were made. These images have sufficient spatial resolution (~8 and
5 pc, respectively) and sensitivity (3-sigma of 1 mJy/beam) to identify most of
the individual SNRs and H II regions and also, in combination with available
data from the Parkes 64-m telescope, the structure of the smooth emission in
that galaxy. In addition, limited data using the sixth antenna at 4.5 to 6-km
baselines are available to distinguish bright point sources (<3 and 2 arcsec,
respectively) and to help estimate sizes of individual sources smaller than the
resolution of the full survey. The resultant database will be valuable for
statistical studies and comparisons with x-ray, optical and infrared surveys of
the LMC with similar resolution.


title: Star Formation and Chemical Evolution at High Redshift

abstract:
  I review the observational characteristics of intermediate-to-high redshift
star forming galaxies, including their star formation rates, dust extinctions,
ISM kinematics, and chemical compositions. I present evidence that the mean
rate of metal enrichment, Delta{Z}/Delta{z}, from z=0--3, as determined from
nebular oxygen abundance measurements in star forming galaxies, is 0.15 dex per
redshift unit for galaxies more luminous than M_B=-20.5. This rate of chemical
enrichment is consistent with the chemical rise in Galactic disk stars. It is
less dramatic than, but perhaps consistent with, the enrichment rate of
0.18--0.26+/-0.07 dex per redshift unit seen in Damped Ly alpha systems, and it
is much less than predicted by many cosmological evolution models. The
high-redshift galaxies observed to date are the most luminous examples from
those epochs, and thus, trace only the greatest cosmological overdensities.
Star formation in the first 1-2 Gyr appears sufficient to elevate ambient
metallicities to near or above the solar value, implying efficient production
and retention of metals in these densest environments.


title: Highest Energy Cosmic Rays

abstract:
  We review the current state and future prospect of ultra high energy cosmic
ray physics and the relationship between cosmic rays and gamma-ray
astrophysics.


title: Lower limits on the Hubble Constant from models of Type Ia Supernovae

abstract:
  By coupling observations of type Ia supernovae with results obtained from the
best available numerical models we constrain the Hubble constant, independently
of any external calibrators. We find an absolute lower limit of Ho > 50
km/s/Mpc. In addition, we construct a Hubble diagram with UVOIR light curves of
12 type Ia supernovae located in the Hubble flow, and when adopting the most
likely values (obtained from 1-D and 3-D deflagration simulations) of the
amount of (56)Ni produced in a typical event, we find values of Ho $\geq$
66$\pm$8 and $\geq$ 78$\pm$9 km/s/Mpc, respectively. Our result may be
difficult to reconcile with recent discussions in the literature as it seems
that an Einstein-de Sitter universe requires Ho $\simeq$ 46 km/s/Mpc in order
to fit the temperature power spectrum of the cosmic microwave background and
maintain the age constraints of the oldest stars.


title: Large-scale magnetic fields from density perturbations

abstract:
  We derive the minimal seed magnetic field which unavoidably arises in the
radiation and matter eras, prior to recombination, by the rotational velocity
of ions and electrons, gravitationally induced by the non-linear evolution of
primordial density perturbations. The resulting magnetic field power-spectrum
is fully determined by the amplitude and spectral index of density
perturbations. The rms amplitude of the seed-field at recombination is B ~
10^{-23} (\lambda/Mpc)^{-2} G, on comoving scales larger than about 1 Mpc.


title:
Hard X-ray Emission Clumps in the gamma-Cygni Supernova Remnant: an
  INTEGRAL-ISGRI View

abstract:
  Spatially resolved images of the galactic supernova remnant G78.2+2.1
(gamma-Cygni) in hard X-ray energy bands from 25 keV to 120 keV are obtained
with the IBIS-ISGRI imager aboard the International Gamma-Ray Astrophysics
Laboratory INTEGRAL. The images are dominated by localized clumps of about ten
arcmin in size. The flux of the most prominent North-Western (NW) clump is (1.7
+/- 0.4) 10^{-11} erg/cm^2/s in the 25-40 keV band. The observed X-ray fluxes
are in agreement with extrapolations of soft X-ray imaging observations of
gamma-Cygni by ASCA GIS and spatially unresolved RXTE PCA data. The positions
of the hard X-ray clumps correlate with bright patches of optical line
emission, possibly indicating the presence of radiative shock waves in a
shocked cloud. The observed spatial structure and spectra are consistent with
model predictions of hard X-ray emission from nonthermal electrons accelerated
by a radiative shock in a supernova interacting with an interstellar cloud, but
the powerful stellar wind of the O9V star HD 193322 is a plausible candidate
for the NW source as well.


title: Insight into AGB and post-AGB stellar evolution with FUSE

abstract:
  FUSE spectroscopy has proved that extremely hot hydrogen-deficient post-AGB
stars (PG1159 stars) display matter on their surface that usually remains
hidden in the region between the H- and He-burning shells of the former AGB
star. Hence, the spectral analysis of PG1159 stars allows to study directly the
chemistry of this intershell region which is the outcome of complicated burning
and mixing processes during AGB evolution. Detailed abundance determinations
provide constraints for these processes which are still poorly understood. With
FUSE we have discovered high neon and fluorine overabundances. There is also a
significant iron deficiency, which may be caused by s-process neutron capture
transforming iron into heavier elements.


title:
On Possible Oxygen/Neon White Dwarfs: H1504+65 and the White Dwarf
  Donors in Ultracompact X-ray Binaries

abstract:
  We discuss the possibility to detect O/Ne white dwarfs by evidence for Ne
overabundances. The hottest known WD, H1504+65, could be the only single WD for
which we might be able to proof its O/Ne nature directly. Apart from this,
strong Ne abundances are known or suspected only from binary systems, namely
from a few novae, and from a handful of LMXBs. We try to verify the hypothesis
that the latter might host strongly ablated O/Ne WD donors, by abundance
analyses of the accretion disks in these systems. In any case, to conclude on
O/Ne WDs just by strong Ne overabundances is problematic, because Ne enrichment
also occurs by settling of this species into the core of C/O WDs.


title:
Identification of a DO White Dwarf and a PG1159 Star in the ESO SN Ia
  Progenitor Survey (SPY)

abstract:
  We present high-resolution VLT spectra of a new DO white dwarf and a new
PG1159 star, which we identified in the ESO SPY survey. The PG1159 star is a
low-gravity, extremely hot (Teff=160,000 K, log g=6) star, having a C/He
dominated atmosphere with considerable amounts of O and Ne (He=38%, C=54%,
O=6%, Ne=2% by mass). It is located within the planetary nebula nuclei
instability strip and pulsations have been discovered. The DO is a unique
object. From HeI/HeII line strengths we found Teff about 60,000 K, however, the
HeII lines are extraordinarily strong and cannot be fitted by any model.


title: ESO-VLT optical spectroscopy of BL Lac objects: I. new redshifts

abstract:
  We report redshift measurements for 12 BL Lacertae objects from a program
aimed at obtaining high signal to noise (up to ~ 500) optical spectroscopy of a
mixed sample of objects. The new observations, gathered with the 8 m ESO Very
Large Telescope, allowed us to detect weak spectral features down to a line
equivalent width as small as ~ 1 Angstrom. The new redshifts fall in the
0.2-1.3 interval. For nine objects we observe emission lines from the active
nucleus. In the remaining three cases absorption lines from the host galaxy are
found. For two objects we also detect absorption lines from intervening
systems.


title: Simulations of Radio Emission from Cosmic Ray Air Showers

abstract:
  Radio emission from cosmic ray air showers has the potential to become an
additional, cost-effective observing technique for cosmic ray research, being
largely complementary to the well-established particle detector and air
fluorescence techniques. We present Monte Carlo simulatios of radio emission
from extensive air showers in the scheme of coherent geosynchrotron radiation
from electron-positron pairs gyrating in the earth's magnetic field.
Preliminary results of our simulations are the predicted frequency, primary
particle energy, shower zenith angle, shower azimuth angle and polarization
dependence of the radio emission. These properties can be directly related to
data measured by LOPES and other experiments.


title:
Starburst at the Expanding Molecular Superbubble in M82: Self-Induced
  Starburst at the Inner Edge of the Superbubble

abstract:
  We present high spatial resolution (2.3"x1.9" or 43 pc x 36 pc at D = 3.9
Mpc) 100 GHz millimeter-wave continuum emission observations with the Nobeyama
Millimeter Array toward an expanding molecular superbubble in the central
region of M82. The 100 GHz continuum image, which is dominated by free-free
emission, revealed that the four strongest peaks are concentrated at the inner
edge of the superbubble along the galactic disk. The production rates of Lyman
continuum photons calculated from 100 GHz continuum flux at these peaks are an
order of magnitude higher than those from the most massive star forming regions
in our Galaxy. At these regions, high velocity ionized gas (traced by H41a and
[Ne II]) can be seen, and H2O and OH masers are also concentrated. The center
of the superbubble, on the other hand, is weak in molecular and free-free
emissions and strong in diffuse hard X-ray emission. These observations suggest
that a strong starburst produced energetic explosions and resultant plasma and
superbubble expansions, and induced the present starburst regions traced by our
100 GHz continuum observations at the inner edge of the molecular superbubble.
These results, therefore, provide the first clear evidence of self-induced
starburst in external galaxies. Starburst at the center of the superbubble, on
the other hand, begins to cease because of a lack of molecular gas. This kind
of intense starburst seems to have occurred several times within 10^6-10^7
years in the central region of M82.


title: Metal rich stars in omega Cen: preliminary FLAMES GTO results

abstract:
  I present preliminary results for a sample of ~700 red giants in omega Cen,
observed during the Ital-FLAMES Consortium GTO time in May 2003, for the
Bologna Project on omega Cen. Preliminary Fe and Ca abundances confirm previous
results: while the metal-poor and intermediate populations show a normal halo
alpha-enhancement of [alpha/Fe]=$+0.3, the most metal-rich stars show a
significantly lower [alpha/Fe]=+0.1. If the metal-rich stars have evolved
within the cluster in a process of self-enrichment, the only way to lower their
alpha-enhancement would be SNe type Ia intervention.


title: AA Dor - An Eclipsing Post Common-Envelope Binary

abstract:
  AA Dor (LB 3459) is an eclipsing, close, single-lined, post common-envelope
binary (PCEB) consisting of an sdOB primary star and an unseen secondary with
an extraordinary small mass - formally a brown dwarf. The brown dwarf may have
been a former planet which survived a common envelope phase and has even gained
mass.
  A recent determination of the components' masses from results of
state-of-the-art NLTE spectral analysis and subsequent comparison to
evolutionary tracks shows a discrepancy between masses derived from
radial-velocity and the eclipse curves. Phase-resolved high-resolution and
high-SN spectroscopy was carried out with FUSE in order to investigate on this
problem.
  We present preliminary results of an ongoing NLTE spectral analysis of FUSE
spectra of the primary.


title:
Hydrodynamic model atmospheres for WR stars: Self-consistent modeling of
  a WC star wind

abstract:
  We present the first non-LTE atmosphere models for WR stars that incorporate
a self-consistent solution of the hydrodynamic equations. The models account
for iron-group line-blanketing and clumping, and compute the hydrodynamic
structure of a radiatively driven wind consistently with the non-LTE radiation
transport in the co-moving frame. We construct a self-consistent wind model
that reproduces all observed properties of an early-type WC star (WC5). We find
that the WR-type mass-loss is initiated at high optical depth by the so-called
`Hot Iron Bump' opacities (Fe IX-XVI). The acceleration of the outer wind
regions is performed by iron-group ions of lower excitation in combination with
C and O. Consequently, the wind structure shows two acceleration regions, one
close to the hydrostatic wind base in the optically thick part of the
atmosphere, and another farther out in the wind. In addition to the radiative
acceleration, the `Iron Bump' opacities are responsible for an intense heating
of deep atmospheric layers. We find that the observed narrow OVI-emissions in
the optical spectra of WC stars originate from this region. By their dependence
on the clumping factor we gain important information about the location where
the density inhomogeneities in WR-winds start to develop.


title:
On the Evolutionary Status of Extremely Hot Helium Stars - are O(He)
  Stars Successors of RCrB Stars?

abstract:
  95% of all stars end their lives as white dwarfs. About 20% of the hot
post-AGB stars are hydrogen deficient. Most of these are the result of a late
helium-shell flash, but the evolutionary status of a fraction of about 10-20%
of the hottest hydrogen-deficient stars, namely four O(He) stars, is as yet
unexplained. They could be the long-searched hot successors of RCrB stars,
which have not been identified up to now. If this turns out to be true, then a
third post-AGB evolutionary sequence is revealed, which is probably the result
of a double degenerate merging process. More generally, understanding details
of merging double degenerate stars is of interest in the context of SN Ia
events and hence cosmology.


title:
Spectral Analysis of Central Stars of PNe Interacting with the
  Interstellar Medium

abstract:
  Planetary Nebulae (PNe) are the result of heavy mass loss of the asymptotic
giant branch (AGB) stars. They are understood in terms of Kwok's (1978)
interacting-winds model as the product of the mass-loss history on the AGB and
the central star (CS) evolution. Since the CS are close to the end of nuclear
burning and at their hottest stage of evolution then, precise modeling of these
pre-white dwarfs is a prerequisite in order to calculate reliable ionizing
fluxes which are crucial input for the presently available 3D photoionization
codes. In the framework of a systematic study of PNe which show evidence for an
interaction with the ISM, we present a NLTE analysis of their CS.


title: Spectral Analysis of Super Soft X-ray Sources: V4743 Sagittarii

abstract:
  Half a year after its outburst, the nova V4743 Sgr evolved into the brightest
super-soft X-ray source in the sky with a flux maximum around 30A, exhibiting
resonance lines of C V, C VI, N VI, N VII, and O VII. We present preliminary
results of an analysis of the XMM-Newton RGS spectra by means of NLTE
model-atmosphere techniques.


title: Turning cool star X-ray spectra upside down

abstract:
  H1504+65 is a young white dwarf with an effective temperature of 200,000 K
and is the hottest post-AGB star ever analysed with detailed model atmospheres.
Chandra LETG+HRC-S spectra have revealed the richest X-ray absorption line
spectrum recorded from a stellar photosphere to date. The line forming regions
in this extremely hot photosphere produce many transitions in absorption that
are also observed in emission in cool star coronae. We have performed a
detailed comparison of Chandra spectra of H1504+65 with those of Procyon and
alpha Cen A and B. State of the art non-LTE model spectra for the hot white
dwarf have enabled us to identify a wealth of absorption lines from highly
ionised O, Ne and Mg. In turn, these features have allowed us to identify
coronal lines whose origins were hitherto unknown.


title: Star complexes and starburst clumps in spiral galaxies

abstract:
  Star complexes are the highest level groupings in the hierarchy of the
embedded young stars, clusters and associations, which obey the size - age
relation. Starburst clumps, superassociations, supergiant HII regions are
different titles for the groupings of the same size as complexes but with
active star formation over all the grouping. The coherent star formation in the
regions of violent star formation was probably triggered by external pressure.
The issue of gravitational boundness of complexes and superassociations is
briefly discussed


title: Synthetic Spectra for Type Ia Supernovae at Early Epochs

abstract:
  We present the current status of our construction of synthetic spectra for
type Ia supernovae. These properly take into account the effects of NLTE and an
adequate representation of line blocking and blanketing. The models are based
on a sophisticated atomic database. We show that the synthetic spectrum
reproduces the observed spectrum of 'normal' SN-Ia near maximum light from the
UV to the near-IR. However, further improvements are necessary before truly
quantitative analyses of observed SN-Ia spectra can be performed. In
particular, the inner boundary condition has to be fundamentally modified. This
is due to the dominance of electron scattering over true absorption processes
coupled with the flat density structure in these objects


title: The Structure of Magnetocentrifugal Winds I. Steady Mass Loading

abstract:
  We present the results of a series of time-dependent numerical simulations of
cold, magnetocentrifugally launched winds from accretion disks. Our simulations
span four and half decades of mass loading; in the context of a disk with a
launching region from $0.1\AU$ to $1.0\AU$ around a $1\solarmass$ star and a
field strength of about $20\gauss$ at the inner disk edge, this amounts to mass
loss rates of $1\times 10^{-9}$ -- $3\times 10^{-5}\solarmassyear$ from each
side of the disk. We find that the degree of collimation of the wind increases
with mass loading; however even the ``lightest'' wind simulated is
significantly collimated compared with the force-free magnetic configuration of
the same magnetic flux distribution. The implication is that for flows from
young stellar objects a radial field approximation is inappropriate.
Surprisingly, the terminal velocity of the wind and the magnetic lever arm are
still well-described by the analytical solutions for a radial field geometry.
We also find that the isodensity contours and Alfv\'en surface are very nearly
self-similar in mass loading. The wind becomes unsteady above some critical
mass loading rate. For a small enough injection speed, we are able to obtain
the first examples of a class of heavily-loaded magnetocentrifugal winds with
magnetic fields completely dominated by the toroidal component all the way to
the launching surface.


title:
Silicate-break galaxies: an efficient selection method of distant
  ultraluminous infrared galaxies

abstract:
  We present a photometric selection method for ULIRGs in the redshift range of
z=1 -- 2. We utilize the most prominent spectral feature of ULIRGs, i.e. the
silicate absorption feature at 9.7 micron and an optimized filter system at
mid-infrared wavelengths. These `silicate-break' galaxies could be selected by
using colour anomalies owing to the silicate absorption feature around 9.7(1+z)
micron. Such filter systems are available on the Spitzer Space Telescope but we
suggest that the most promising selection criteria would be given with
mid-infrared bands of ASTRO-F satellite due to a more comprehensive set of
filter bands than that of Spitzer. We study the selection method of
silicate-break galaxies with the SED model of both starbursts and quiescent
star-forming galaxies, and then verify the method by using the observed spectra
of nearby galaxies. We would expect that about 1000 candidates of
silicate-break galaxies could be detected per square degree in current and
future mid-infrared surveys. The silicate-break selection criteria will break
the degeneracy between various galaxy evolution models for extragalactic source
counts and place strong limits on the star formation activity at z=1 -- 2.
Applying our silicate-break technique to initial Spitzer results we have
tentatively identified the first candidate silicate-break galaxy at z=1.6.


title: Discovery of a Cool, Massive, and Metal-Rich DAZ White Dwarf

abstract:
  We report the discovery of a new metal-rich DAZ white dwarf, GD 362. High
signal-to-noise optical spectroscopy reveals the presence of spectral lines
from hydrogen as well as CaI, CaII, MgI, and FeI. A detailed model atmosphere
analysis of this star yields an effective temperature of Teff = 9740 +/- 50 K,
a surface gravity of log g = 9.12 +/- 0.07, and photospheric abundances of log
Ca/H = -5.2 +/- 0.1, log Mg/H = -4.8 +/- 0.1, and log Fe/H = -4.5 +/- 0.1.
White dwarf cooling models are used to derive a mass of 1.24 Mo for GD 362,
making it the most massive and metal-rich DAZ uncovered to date. The problems
related to the presence of such large metal abundances in a nearby (d ~ 25 pc)
white dwarf in terms of an accretion scenario are briefly discussed.


title:
La recherche de naines brunes et d'exoplanetes: developpement d'une
  technique d'imagerie multibande

abstract:
  The technique of simultaneous spectral differential imaging (SSDI) is used to
image directly brown dwarfs and exoplanets around nearby stars. An analytical
PSF model is first presented with numerical simulations to estimate the PSF
noise attenuation performance. A three-wavelength infrared camera (TRIDENT)
implementing the SSDI technique is then described. Results from a survey of 35
nearby stars carried out with TRIDENT at the Canada-France-Hawaii telescope are
presented. Performance estimates show that a companion 9.5 magnitudes fainter
than a star is detectable (6 sigma) at 0.5" separation. An analysis of the
observations suggests that non-common path aberrations between TRIDENT optical
channels are the limiting factor preventing further PSF noise attenuation. A
new camera concept using a multi-wavelength detector featuring a microlens
array combined with micro-filters is presented to overcome the non-common path
aberration problem. Another imaging technique, differential angular imaging, is
also discussed to obtain a reference PSF in each optical channel while
observing a target. Finally, the accuracy of FFT-based image shifting, scaling
and rotating algorithms is studied to show that a companion 10^9 times fainter
than a star can theoretically be detected by those algorithms.


title: Spitzer IRAC Observations of Star Formation in N159 in the LMC

abstract:
  We present observations of the giant HII region complex N159 in the LMC using
IRAC on the {\it Spitzer Space Telescope}. One of the two objects previously
identified as protostars in N159 has an SED consistent with classification as a
Class I young stellar object (YSO) and the other is probably a Class I YSO as
well, making these two stars the youngest stars known outside the Milky Way. We
identify two other sources that may also be Class I YSOs. One component,
N159AN, is completely hidden at optical wavelengths, but is very prominent in
the infrared. The integrated luminosity of the entire complex is L $\approx
9\times10^6$L$_{\odot}$, consistent with the observed radio emission assuming a
normal Galactic initial mass function (IMF). There is no evidence for a red
supergiant population indicative of an older burst of star formation. The N159
complex is 50 pc in diameter, larger in physical size than typical HII regions
in the Milky Way with comparable luminosity. We argue that all of the
individual components are related in their star formation history. The
morphology of the region is consistent with a wind blown bubble $\approx
1-2Myr-old that has initiated star formation now taking place at the rim. Other
than its large physical size, star formation in N159 appears to be
indistinguishable from star formation in the Milky Way.


title: Predictions for high-frequency radio surveys of extragalactic sources

abstract:
  We present detailed predictions of the contributions of the various source
populations to the counts at frequencies of tens of GHz. New evolutionary
models are worked out for flat-spectrum radio quasars, BL Lac objects, and
steep-spectrum sources. Source populations characterized by spectra peaking at
high radio frequencies, such as extreme GPS sources, ADAF/ADIOS sources and
early phases of gamma-ray burst afterglows are also dealt with. The counts of
different populations of star-forming galaxies (normal spirals, starbursts,
high-z galaxies detected by SCUBA and MAMBO surveys, interpreted as
proto-spheroidal galaxies) are estimated taking into account both synchrotron
and free-free emission, and dust re-radiation. Our analysis is completed by
updated counts of Sunyaev-Zeldovich effects in clusters of galaxies and by a
preliminary estimate of galactic-scale Sunyaev-Zeldovich signals associated to
proto-galactic plasma.


title:
Missing Mass, Dark Energy and the Acceleration of the Universe. Is
  Acceleration Here to Stay?

abstract:
  In this paper we present an alternative explanation to the acceleration of
the universe and the dark energy problems in terms of the Friedmann
Thermodynamics. This model has the capability of making definite predictions
in-line with the current observations of the universe. According to this model,
cosmos was expanding slower at the beginning. During the galaxy formation era
(with redshifts [0.54-0.91]), due to a change in the global equation of state
it accelerates for a brief period of time. We expect to see this as a
discontinuity in the Hubble diagram. Recent data about the galaxies with
redshifts 0.5<z<0.9 displays this discontinuity clearly. We expect the
deceleration to re-appear as more data with redshifts z>1 is gathered. These
galaxies will be among the very first galaxies formed in the universe, thus
still showing the kinematics of the pre-galaxy formation era. This point is now
clearly evidenced in the recent data by Riess et al. on Type Ia supernovae with
redshifts z>1.25 (2004 astro-ph/0402512). In our model, galaxies with redshifts
0<z<0.5 should reflect the kinematics of the universe after the transition is
completed. These galaxies are now receding from each other faster. However, for
redshifts towards the upper end of this range we still expect to see
deceleration. This is in contrast with the predictions of the dark energy
models.


title: Galaxy-galaxy Lensing: Dissipationless Simulations Versus the Halo Model

abstract:
  Galaxy-galaxy lensing is a powerful probe of the relation between galaxies
and dark matter halos, but its theoretical interpretation requires a careful
modeling of various contributions, such as the contribution from central and
satellite galaxies. For this purpose, a phenomenological approach based on the
halo model has been developed, allowing for fast exploration of the parameter
space of models. In this paper, we investigate the ability of the halo model to
extract information from the g-g weak lensing signal by comparing it to
high-resolution dissipationless simulations that resolve subhalos. We find that
the halo model reliably determines parameters such as the host halo mass of
central galaxies, the fraction of galaxies that are satellites, and their
radial distribution inside larger halos. If there is a significant scatter
present in the central galaxy host halo mass distribution, then the mean and
median mass of that distribution can differ significantly from one another, and
the halo model mass determination lies between the two. This result suggests
that when analyzing the data, galaxy subsamples with a narrow central galaxy
halo mass distribution, such as those based on stellar mass, should be chosen
for a simpler interpretation of the results.


title: On lambda and omega measurements and acceleration of universe expansion

abstract:
  Luminisity distances to the high-redshift Ia supernovas measured by the
Supernova Cosmology Project team with the relativistic correction factors for
redshift and time dilation led to the sensational conclusion about acceleration
of universe expansion. The effect of relativistic aberration of high-redshift
sources requires an additional correcting factor for the observed luminosities
of SN Ia supernovas which can reduce the data to fit the universe with lambda =
0, i.e. without acceleration.


title:
Parameter Dependence of Transonic Accretion onto a Black Hole in the
  Presence of Bremsstrahlung and Synchrotron Cooling

abstract:
  The topologies are obtained for accretion flows around black holes as the
parameters, accretion rate and specific angular momentum are varied.
Paczy{\'n}ski-Wiita pseudo-Newtonian potential is used to mimic the
gravitational field of a Schwarzschild black hole. Both stellar
mass($14M_{\odot}$) and supermassive($10^8M_{\odot}$) black holes are
considered. The effects of bremsstrahlung and synchrotron cooling processes on
the flow dynamics are studied. Rankine-Hugoniot conditions are checked for
possible shock formation of solution branches of the topology. Stability of the
branches and the boundary conditions of the flow are likely to decide the
uniqueness of the solution.


title:
A Running Spectral Index in Supersymmetric Dark-Matter Models with
  Quasi-Stable Charged Particles

abstract:
  We show that charged-particles decaying in the early Universe can induce a
scale-dependent or `running' spectral index in the small-scale linear and
nonlinear matter power spectrum and discuss examples of this effect in minimal
supersymmetric models in which the lightest neutralino is a viable
cold-dark-matter candidate. We find configurations in which the neutralino
relic density is set by coannihilations with a long-lived stau, and the late
decay of staus partially suppresses the linear matter power spectrum. Nonlinear
evolution on small scales then causes the modified linear power spectrum to
evolve to a nonlinear power spectrum similar (but different in detail) to
models parametrized by a constant running $\alpha_{s}=d n_{s}/d{\rm ln} k$ by
redshifts of 2 to 4. Thus, Lyman-$\alpha$ forest observations, which probe the
matter power spectrum at these redshifts, might not discriminate between the
two effects. However, a measurement of the angular power spectrum of primordial
21-cm radiation from redshift $z \approx 30$--$200$ might distinguish between
this charged-decay model and a primordial running spectral index. The direct
production of a long-lived charged particle at future colliders is a dramatic
prediction of this model.


title:
Force-Free Magnetosphere of an Accretion Disk -- Black Hole System. II.
  Kerr Geometry

abstract:
  We consider a stationary axisymmetric force-free degenerate magnetosphere of
a rotating Kerr black hole surrounded by a thin Keplerian infinitely-conducting
accretion disk. We focus on the closed-field geometry characterize by a direct
magnetic coupling between the disk and the hole's event horizon. We first argue
that the hole's rotation necessarily limits the radial extent of the force-free
link on the disk surface: the faster the hole rotates, the smaller the
magnetically-connected inner part of the disk has to be. We then show that this
is indeed the case by solving numerically the Grad--Shafranov equation--the
main differential equation describing the structure of the magnetosphere. An
important element in our approach is the use of the regularity condition at the
inner light cylinder to fix the poloidal current as a function of the poloidal
magnetic flux. As an outcome of our computations, we are able to chart out the
maximum allowable size of the portion of the disk that is magnetically
connected to the hole as a function of the black hole spin. We also calculate
the angular momentum and energy transfer between the hole and the disk that
takes place via the direct magnetic link. We find that both of these quantities
grow rapidly and that their deposition becomes highly concentrated near the
inner edge of the disk as the black hole spin is increased.


title:
Extracting Rotational Energy in Supernova Progenitors: Transient
  Poynting Flux Growth vs. Turbulent Dissipation

abstract:
  Observational evidence for anisotropy in supernovae (SN) may signal the
importance of angular momentum and differential rotation in the progenitors.
Free energy in differential rotation and rotation can be extracted magnetically
or via turbulent dissipation. The importance that magnetohydrodyamic jets and
coronae may play in driving SN motivates understanding large scale dynamos in
SN progenitors. We develop a dynamical large scale interface dynamo model in
which the differential rotation and rotation deplete both through Poynting flux
and turbulent diffusion. We apply the model to a differentially rotating core
surrounded by a convection zone of a SN progenitor from a initial 15$M_\odot$
star. Unlike the Sun, the dynamo is transient because the differential rotation
is primarily due to the initial collapse. Up to $\sim 10^{51}$erg can be
drained into time-integrated Poynting flux and heat, the relative fraction of
which depends on the relative amount of turbulence in the shear layer vs.
convection zone and the fraction of the shear layer into which the magnetic
field penetrates. Both sinks can help facilitate explosions and could lead to
different levels of anisotropy and pulsar kicks. In all cases, the poloidal
magnetic field is much weaker than the toroidal field, and the Poynting flux is
lower than previous estimates which invoke the magnitude of the total magnetic
energy. A signature of a large scale dynamo is that the oscillation of the
associated
  Poynting flux on $\sim 1$ sec time scales, implying the same for the energy
delivery to a SN.


title: Composition of the Solar Interior: Information from Isotope Ratios

abstract:
  Measurements are reviewed showing that the interior of the Sun, the inner
planets, and ordinary meteorites consist mostly of the same elements: Iron,
oxygen, nickel, silicon, magnesium, sulfur and calcium. These results do not
support the standard solar model.


title: A Change in the Physical State of $\eta$ Carinae?

abstract:
  During $\eta$ Car's spectroscopic event in mid-2003, the stellar wind's
bright H$\alpha$ and H$\beta$ emission lines temporarily had a distinctive
shape unlike that reported on any previous occasion, and particularly unlike
the 1997--98 event. Evidently the structure of the wind changed between 1997
and 2003. Combining this with other evidence, we suspect that the star may now
be passing through a rapid stage in its recovery from the Great Eruption seen
160 years ago. In any case the data indicate that successive spectroscopic
events differ, and the hydrogen line profiles are quantitative clues to the
abnormal structure of the wind during a spectroscopic event.


title: Pushing the Boundaries of the Cl 1604 Supercluster at z~0.9

abstract:
  The Cl 1604 supercluster at z~0.9 is known to contain at least four distinct
member clusters, separated in both projection and redshift. In this paper we
present deep, multicolor wide-field imaging of a region spanning ~45' on a
side, corresponding to 21 h^{-1}_{70} Mpc (physical) at the supercluster
redshift. We select galaxies whose colors correspond to those of
spectroscopically confirmed cluster members in the r' vs. (r'-i')
color-magnitude diagram. Using an adaptive kernel, we generate a map of the
projected red galaxy density and identify numerous new candidate clusters which
are likely supercluster members. Assuming that all of the density peaks are
associated with the supercluster, its transverse size is ~10 h^{-1}_{70} Mpc,
which is still significantly smaller than the nearly 93 h^{-1}_{70} Mpc depth
in redshift space.


title: Modeling the 3C 120 Radio Jet from 1 to 30 Milliarcseconds

abstract:
  The predicted spatial development of helical structures along an expanding
jet are used to model observed structures and motions in the 3C 120 jet. Proper
motions of helical components associated with the pattern and of other
components that move through the pattern provide estimates of flow and helical
pattern speeds. Theoretical modeling allows determination of sound speeds as a
function of jet viewing angle. Jet morphology argues against viewing angles
larger than 12 deg. At a 12 deg viewing angle the most likely scenario involves
a decline in jet sound speed from c/3 < a_j < c/1.7 at ~0.5 mas from the core
to 0.1c < a_j < 0.25c at ~25 mas from the core accompanied by some acceleration
in the jet flow from Lorentz factor < 5 to Lorentz factor > 7. At smaller
viewing angles the jet sound speed is lower and at a 6 deg viewing angle the
jet sound speed is about a factor 2 less but the flow Lorentz factor is
comparable. The decline in radio intensity is on the order of what would be
associated with isothermal jet expansion. Knot interknot intensity variations
are greater than would be expected from adiabatic compressions associated with
the helical twist and we infer the presence of a shock along the leading edge
of the helical twist. Our results imply that the macroscopic heating of the
expanding jet fluid is less than the microscopic energization of the
synchrotron radiating relativistic electrons.


title: The DEEP2 Galaxy Redshift Survey: First results on galaxy groups

abstract:
  We use the first 25% of the DEEP2 Galaxy Redshift Survey spectroscopic data
to identify groups and clusters of galaxies in redshift space. The data set
contains 8370 galaxies with confirmed redshifts in the range 0.7 <= z <= 1.4,
over one square degree on the sky. Groups are identified using an algorithm
(the Voronoi-Delaunay Method) that has been shown to accurately reproduce the
statistics of groups in simulated DEEP2-like samples. We optimize this
algorithm for the DEEP2 survey by applying it to realistic mock galaxy catalogs
and assessing the results using a stringent set of criteria for measuring
group-finding success, which we develop and describe in detail here. We find in
particular that the group-finder can successfully identify ~78% of real groups
and that ~79% of the galaxies that are true members of groups can be identified
as such. Conversely, we estimate that ~55% of the groups we find can be
definitively identified with real groups and that ~46% of the galaxies we place
into groups are interloper field galaxies. Most importantly, we find that it is
possible to measure the distribution of groups in redshift and velocity
dispersion, n(sigma,z), to an accuracy limited by cosmic variance, for
dispersions greater than 350km/s. We anticipate that such measurements will
allow strong constraints to be placed on the equation of state of the dark
energy in the future. Finally, we present the first DEEP2 group catalog, which
assigns 32% of the galaxies to 899 distinct groups with two or more members,
153 of which have velocity dispersions above 350km/s. We provide locations,
redshifts and properties for this high-dispersion subsample. This catalog
represents the largest sample to date of spectroscopically detected groups at
z~1.


title:
The Structural Properties of Isolated Galaxies, Spiral-Spiral Pairs, and
  Mergers: The Robustness of Galaxy Morphology During Secular Evolution

abstract:
  We present a structural analysis of nearby galaxies in spiral-spiral pairs in
optical BVRI bands and compare with the structures of isolated spiral galaxies
and galaxies in ongoing mergers. We use these comparisons to determine how
galaxy structure changes during galaxy interactions and mergers. We analyze
light concentration (C), asymmetry (A), and clumpiness (S) parameters, and use
the projections of CAS parameter space to compare these samples. We find that
the CAS parameters of paired galaxies are correlated with the projected
separations of the pair. For the widest and closest pairs, the CAS parameters
tend to be similar to those of isolated and ongoing major mergers (ULIRGs),
respectively. Our results imply that galaxy CAS morphology is a robust quantity
that only changes significantly during a strong interaction or major merger.
The typical time-scale for this change in our paired sample, based on dynamical
friction arguments, is short, t ~ 0.1 - 0.5 Gyr. We find average enhancement
factors for the spiral pair asymmetries and clumpiness values of ~2.2 and 1.5.
The S parameter, which is related to star formation activity, has a moderate
level of enhancement suggesting that this activity in modern spirals depends
more on internal processes than on external conditions. We furthermore test the
statistical criterion for picking up interacting galaxies in an automated way
by using the A-S projection plane. The diversity of our spiral pair sample in
the CAS space suggests that structural/SF/morphological properties of
interacting galaxies change abruptly only when the interaction becomes very
strong and that the criteria for finding galaxies involved in major mergers
from Conselice (2003) is effective.


title: Initial test of a Bayesian approach to solar flare prediction

abstract:
  A test of a new Bayesian approach to solar flare prediction (Wheatland 2004a)
is presented. The approach uses the past history of flaring together with
phenomenological rules of flare statistics to make a prediction for the
probability of occurrence of a large flare within an interval of time, or to
refine an initial prediction (which may incorporate other information). The
test of the method is based on data from the Geostationary Observational
Environmental Satellites (GOES), and involves whole-Sun prediction of soft
X-ray flares for 1976-2003. The results show that the method somewhat
over-predicts the probability of all events above a moderate size, but performs
well in predicting large events.


title: Efficiency of Nonlinear Particle Acceleration at Cosmic Structure Shocks

abstract:
  We have calculated the evolution of cosmic ray (CR) modified astrophysical
shocks for a wide range of shock Mach numbers and shock speeds through
numerical simulations of diffusive shock acceleration (DSA) in 1D quasi-
parallel plane shocks. The simulations include thermal leakage injection of
seed CRs, as well as pre-existing, upstream CR populations. Bohm-like diffusion
is assumed. We model shocks similar to those expected around cosmic structure
pancakes as well as other accretion shocks driven by flows with upstream gas
temperatures in the range $T_0=10^4-10^{7.6}$K and shock Mach numbers spanning
$M_s=2.4-133$. We show that CR modified shocks evolve to time-asymptotic states
by the time injected particles are accelerated to moderately relativistic
energies ($p/mc \gsim 1$), and that two shocks with the same Mach number, but
with different shock speeds, evolve qualitatively similarly when the results
are presented in terms of a characteristic diffusion length and diffusion time.
For these models the time asymptotic value for the CR acceleration efficiency
is controlled mainly by shock Mach number. The modeled high Mach number shocks
all evolve towards efficiencies $\sim 50$%, regardless of the upstream CR
pressure. On the other hand, the upstream CR pressure increases the overall CR
energy in moderate strength shocks ($M_s \sim {\rm a few}$). (abridged)


title:
Peculiar velocities in the Zone of Avoidance: Determining the Distance
  to the Norma cluster

abstract:
  Deep J, H and Ks photometry of the low Galactic latitude Norma cluster has
been obtained with the 1.4-m Infrared Survey Facility (IRSF) and with SOFI on
the NTT. Together with spectroscopy taken at the Anglo-Australian Observatory
using 2dF, the near-infrared Fundamental Plane of the Norma cluster will be
used to determine the distance to this cluster and to assess its location
within the Great Attractor overdensity. Potential systematic uncertainties
related to the determination of peculiar velocities in the Zone of Avoidance
are discussed in some detail. In particular the effects (uncertainties,
systematics and scatter) of extinction and star-crowding on the derived
magnitudes at low latitudes are investigated in great detail. We present a
first look at the emerging Ks-band Fundamental Plane of the Norma cluster. We
expect an uncertainty of ~ 3% (~ 150 km/s at the distance of the Norma cluster)
in our final Fundamental Plane distance estimate based on 76 galaxies.


title: Rotation-induced mixing in red giant stars

abstract:
  Red giant stars, both in the field and in globular clusters, present
abundance anomalies that can not be explained by standard stellar evolution
models. Some of these peculiarities clearly point towards the existence of
extra-mixing processes at play inside the stars, the nature of which remains
unclear. We present new results of the evolution of a typical globular cluster
red giant including a fully consistent treatment of rotation-induced mixing
from the ZAMS up to the RGB tip. The uncertainties pertaining to the
prescriptions of angular momentum and chemicals transport inside the star are
discussed.