title: Dark Energy from Mass Varying Neutrinos

abstract:
  We show that mass varying neutrinos (MaVaNs) can behave as a negative
pressure fluid which could be the origin of the cosmic acceleration. We derive
a model independent relation between the neutrino mass and the equation of
state parameter of the neutrino dark energy, which is applicable for general
theories of mass varying particles. The neutrino mass depends on the local
neutrino density and the observed neutrino mass can exceed the cosmological
bound on a constant neutrino mass. We discuss microscopic realizations of the
MaVaN acceleration scenario, which involve a sterile neutrino. We consider
naturalness constraints for mass varying particles, and find that both ev
cutoffs and ev mass particles are needed to avoid fine-tuning. These
considerations give a (current) mass of order an eV for the sterile neutrino in
microscopic realizations, which could be detectable at MiniBooNE. Because the
sterile neutrino was much heavier at earlier times, constraints from big bang
nucleosynthesis on additional states are not problematic. We consider regions
of high neutrino density and find that the most likely place today to find
neutrino masses which are significantly different from the neutrino masses in
our solar system is in a supernova. The possibility of different neutrino mass
in different regions of the galaxy and the local group could be significant for
Z-burst models of ultra-high energy cosmic rays. We also consider the cosmology
of and the constraints on the ``acceleron'', the scalar field which is
responsible for the varying neutrino mass, and briefly discuss neutrino density
dependent variations in other constants, such as the fine structure constant.


title: Optical and Infrared Observations of Anomalous X-ray Pulsars

abstract:
  The detection of optical/infrared counterparts to Anomalous X-ray Pulsars
(AXPs) has greatly increased our understanding of these systems. Models for the
AXP phenomenon were based upon their X-ray emission, and all but the magnetar
model made predictions for the optical/infrared that have now been falsified.
  With detections in hand, detailed studies of the optical/infrared to X-ray
flux ratios, variability, and the spectral energy distributions have become
possible. We present new data on two AXPs taken with Keck and Magellan, and
compare the results with predictions made in the context of the magnetar model,
in which the emission is due to ion currents flowing in the >10e14 G
magnetosphere of young neutron stars.


title: Advances in r-Process Nucleosynthesis

abstract:
  During the last several decades, there have been a number of advances in
understanding the rapid neutron-capture process (i.e., the r-process). These
advances include large quantities of high-resolution spectroscopic abundance
data of neutron-capture elements, improved astrophysical models, and
increasingly more precise nuclear and atomic physics data. The elemental
abundances of the heavy neutron-capture elements, from Ba through the third
r-process peak, in low-metallicity ([Fe/H] <~ -2.5) Galactic halo stars are
consistent with the scaled (i.e., relative) solar system r-process abundance
distribution. These abundance comparisons suggest that for elements with Z >=
56 the r-process is robust--appearing to operate in a relatively consistent
manner over the history of the Galaxy--and place stringent constraints on
r-process models. While not yet identified, neutron-rich ejecta outside of the
core in a collapsing (Type II, Ib) supernova continues to be a promising site
for the r-process. Neutron star binary mergers might also be a possible
alternative site. Abundance comparisons of lighter n-capture elements in halo
stars show variations with the scaled solar r-process curve and might suggest
either multiple r-process sites, or, at least, different synthesis conditions
in the same astrophysical site. Constraints on r-process models and clues to
the progenitors of the halo stars--the earliest generations of Galactic
stars--are also provided by the star-to-star abundance scatter of [Eu/Fe] at
low metallicities in the early Galaxy. Finally, abundance observations of
long-lived radioactive elements (such as Th and U) produced in the r-process
can be used to determine the chronometric ages of the oldest stars, placing
constraints on the lower limit age estimates of the Galaxy and the Universe.


title:
Reassessment of the GZK cutoff in the spectrum of UHE cosmic rays in a
  universe with low photon-baryon ratio

abstract:
  A prediction of standard Big Bang cosmology is that the observed UHECR
(ultra-high-energy cosmic rays) spectrum will exhibit a cutoff at the GKZ
limit, resulting from interaction with the photons that constitute the cosmic
microwave background. We show that for the Quasi-Static Universe (QSU) model,
in which photon energy is an invariant in the cosmological reference frame, the
photon number density in the universe today is a factor of 10^9 less than in
the standard model. As a consequence, the mean free path of UHECRs will exceed
the horizon distance of the universe, rendering it essentially transparent to
UHECRs. The QSU model therefore predicts that no cutoff will be observed in the
UHECR spectrum.


title: GRB 030227: the first multiwavelength afterglow of an INTEGRAL GRB

abstract:
  We present multiwavelength observations of a gamma-ray burst detected by
INTEGRAL (GRB 030227) between 5.3 hours and ~1.7 days after the event. Here we
report the discovery of a dim optical afterglow (OA) that would not have been
detected by many previous searches due to its faintess (R~23). This OA was seen
to decline following a power law decay with index Alpha_R= -0.95 +/- 0.16. The
spectral index Beta_opt/NIR yielded -1.25 +/- 0.14. These values may be
explained by a relativistic expansion of a fireball (with p = 2.0) in the
cooling regime. We also find evidence for inverse Compton scattering in X-rays.


title: On the Flux of Extra-Solar Dust in Earth's Atmosphere

abstract:
  Micron size extrasolar dust particles have been convincingly detected by
satellites. Larger extrasolar meteoroids (5-35 microns) have most likely been
detected by ground based radar at Arecibo and New Zealand. We present estimates
of the minimum detectable particle sizes and collecting areas for both radar
systems. We show that particles larger than about 10 microns can propagate for
tens of parsecs through the interstellar medium, opening up the possibility
that ground based radar systems can detect AGB stars, young stellar objects
such as T Tauri stars, and debris disks around Vega-like stars. We provide
analytical and numerical estimates of the ejection velocity in the case of a
debris disk interacting with a Jupiter mass planet. We provide rough estimates
of the flux of large micrometeoroids from all three classes of sources. Current
radar systems are unlikely to detect significant numbers of meteors from debris
disks such as Beta Pictoris. However, we suggest improvements to radar systems
that should allow for the detection of multiple examples of all three classes.


title: The Rotation Of The Deep Solar Layers

abstract:
  From the analysis of low-order GOLF+MDI sectoral modes and LOWL data (l > 3),
we derive the solar radial rotation profile assuming no latitudinal dependance
in the solar core. These low-order acoustic modes contain the most
statistically significant information about rotation of the deepest solar
layers and should be least influenced by internal variability associated with
the solar dynamo. After correction of the sectoral splittings for their
contamination by the rotation of the higher latitudes, we obtain a flat
rotation profile down to 0.2 solar radius.


title:
Constraints on the Energy Content of the Universe from a Combination of
  Galaxy Cluster Observables

abstract:
  We demonstrate that constraints on cosmological parameters from the
distribution of clusters as a function of redshift (dN/dz) are complementary to
accurate angular diameter distance (D_A) measurements to clusters, and their
combination significantly tightens constraints on the energy density content of
the Universe. The number counts can be obtained from X-ray and/or SZ
(Sunyaev-Zel'dovich effect) surveys, and the angular diameter distances can be
determined from deep observations of the intra-cluster gas using their thermal
bremsstrahlung X-ray emission and the SZ effect. We combine constraints from
simulated cluster number counts expected from a 12 deg^2 SZ cluster survey and
constraints from simulated angular diameter distance measurements based on the
X-ray/SZ method assuming a statistical accuracy of 10% in the angular diameter
distance determination of 100 clusters with redshifts less than 1.5. We find
that Omega_m can be determined within about 25%, Omega_Lambda within 20%, and w
within 16%. We show that combined dN/dz + D_A constraints can be used to
constrain the different energy densities in the Universe even in the presence
of a few percent redshift dependent systematic error in D_A. We also address
the question of how best to select clusters of galaxies for accurate diameter
distance determinations. We show that the joint dN/dz + D_A constraints on
cosmological parameters for a fixed target accuracy in the energy density
parameters are optimized by selecting clusters with redshift upper cut--offs in
the range 0.5 < z < 1.


title: Tsunamis in Galaxy Clusters: Heating of Cool Cores by Acoustic Waves

abstract:
  Using an analytical model and numerical simulations, we show that acoustic
waves generated by turbulent motion in intracluster medium effectively heat the
central region of a so-called ``cooling flow'' cluster. We assume that the
turbulence is generated by substructure motion in a cluster or cluster mergers.
Our analytical model can reproduce observed density and temperature profiles of
a few clusters. We also show that waves can transfer more energy from the outer
region of a cluster than thermal conduction alone. Numerical simulations
generally support the results of the analytical study.


title:
Chandra Observation of Diffuse Gas and LMXBs in the Elliptical Galaxy
  NGC 4649 (M60)

abstract:
  We present a Chandra X-ray observation of the X-ray bright E2 elliptical
galaxy NGC4649. In addition to bright diffuse emission, we resolve 165 discrete
sources, most of which are presumably low-mass X-ray binaries (LMXBs). As found
in previous studies, the luminosity function of the resolved sources is
well-fit by a broken power-law. In NGC4697 and NGC1553, the break luminosity
was comparable to the Eddington luminosity of a $1.4 M_{\odot}$ neutron star.
One possible interpretation of this result is that those sources with
luminosities above the break are accreting black holes and those below are
mainly accreting neutron stars. The total X-ray spectrum of the resolved
sources is well-fit by a hard power-law, while the diffuse spectrum requires a
hard and a soft component, presumably due to the relatively soft diffuse gas
and the harder unresolved sources. We also find evidence for structure in the
diffuse emission near the center of NGC4649. Specifically, there appear to be
bright "fingers" of emission extending from the center of the galaxy and a 5
arcsec long bar at the center of the galaxy. The fingers are morphologically
similar to radial features seen in two-dimensional hydrodynamic simulations of
cooling flows in elliptical galaxies, and although their other properties do
not match the predictions of the particular simulations used we conclude that
the radial fingers might be due to convective motions of hot outflowing gas and
cooler inflowing gas. The bar is coincident with the central extended radio
source; we conclude that the bar may be caused by weak shocks in the diffuse
gas from an undetected low-luminosity active galactic nucleus (AGN).


title: Cosmic rays, stellar evolution, and supernova physics

abstract:
  Most cosmic rays are thought to be accelerated by the shocks of supernova
explosions of very massive stars. Here we review one quantitative proposal,
which predicted the spectral slopes, bend and cutoff about the cosmic ray
spectrum across the spectral bend or "knee" near 3x10^15 eV in 1993. Many of
the specific predictions have now been verified, and so it may be appropiate to
investigate the consequences of that proposal. The successful fit to the cosmic
ray data across the knee suggests: 1) very massive stars, above about 20 to 25
solar masses all converge to a common final state; 2) the supernova explosion
of these very massive stars is caused by a combination of rotation, magnetic
fields and the gravitational potential, just as proposed by G. Bisnovatyi-Kogan
in 1970, based on an earlier suggestion by N.S. Kardashev in 1964; 3) their
stellar winds as well as the explosion provide the main injection of magnetic
fields into the interstellar medium; 4) the explosive energy of these
supernovae is about 10^52 erg; 5) the explosion is extremely anisotropic, which
may unify several classes of observed supernova types; 6) gamma ray bursts may
be the ultimate version of such an explosion in the case the collapse leads to
a black hole; 7)it is plausible that the luminosity of the supernova integrated
over all aspect angles is also the same for all these massive star explosions,
leading to 8) a possibly very bright standard candle, if we could just find a
correction for the extreme asphericity. This may solve the problem of what the
mechanism of supernova explosions is for very massive stars, where most cosmic
rays and magnetic fields come from, and may also point the way to a unifying
scheme for supernova explosions and gamma ray bursts.


title: New results on neutron star low mass transients in the quiescence

abstract:
  We review the main observational properties of neutron star low mass
transients in quiescence. We first survey the discoveries of BeppoSAX. We then
focus on recent discoveries by Chandra and XMM-Newton, with special emphsasis
on the detection of the quiescent counterpart of SAX J1808.4-3658 and the study
of variability in the quiescent state.


title:
The large extent of dark matter haloes probed by the formation of tidal
  dwarf galaxies

abstract:
  In several interacting systems, gas accumulations as massive as 10^9 solar
masses are observed near the tip of tidal tails, and are thought to be possible
progenitors of Tidal Dwarf Galaxies. Using N-body simulations of galaxy
interactions, we show that the existence of such features requires that dark
matter haloes around spiral galaxies extend at least ten times further than the
stellar disks. The massive gas clouds formed in our simulations have a
kinematical origin and gravitationally collapse into dwarf galaxies that often
survive for a few billion years.


title:
The MINE collaboration: multi-wavelength observations of microquasars
  with INTEGRAL, prospects with HESS and ANTARES

abstract:
  We present the international collaboration MINE (Multi-lambda Integral
NEtwork) aimed at conducting multi-wavelength observations of X-ray binaries
and microquasars simultaneously with INTEGRAL. The first results on GRS
1915+105 are encouraging and those to come should help us to understand the
physics of the accretion and ejection phenomena around a compact object. A
collaboration such as MINE could be very useful for observing quasars and
microquasars simultaneously with HESS and later with ANTARES.


title:
A search for distant radio galaxies from SUMSS and NVSS: I. Sample
  definition, radio and K-band imaging

abstract:
  We present the first results from a pilot study to search for distant radio
galaxies in the southern hemisphere (delta < -32). Within a 360 deg^2 region of
sky, we define a sample of 76 ultra-steep spectrum (USS) radio sources from the
843 MHz Sydney University Molonglo Sky Survey (SUMSS) and 1.4 GHz NRAO VLA Sky
Survey (NVSS) radio surveys with alpha_843^1400 < -1.3 and S_1400 > 15 mJy. We
observed 71 sources without bright optical or near-infrared counterparts at
1.385 GHz with the ATCA, providing ~5" resolution images and sub-arcsec
positional accuracy. To identify their host galaxies, we obtained near-IR
K-band images with IRIS2 at the AAT and SofI at the NTT. We identify 92% of the
USS sources down to K~20.5. The SUMSS-NVSS USS sources have a surface density
more than 4 times higher than USS sources selected at lower frequencies. This
is due to the higher effective selection frequency, and the well-matched
resolutions of both surveys constructed using the same source fitting
algorithm. The scattering of alpha >-1.3 sources into the USS sample due to
spectral index uncertainties can account for only 35% of the observed USS
sources. Since our sample appears to contain a similar fraction of very distant
(z>3) galaxies, selecting USS sources from SUMSS-NVSS should allow us to
identify large numbers of massive galaxies at high redshift.


title:
Element stratification in main sequence stars and its effect on stellar
  oscillations

abstract:
  The element settling due to the combined effects of gravity, thermal
gradient, radiative acceleration and concentration gradient may lead to
important abundance variations inside the stars, which cannot be neglected in
the computations of stellar structure. These processes where first introduced
to account for abundance anomalies in "peculiar stars", but their importance in
the so-called "normal" stars is now fully acknowledged, specially after the
evidence of helium settling in the Sun from helioseismology. These microscopic
processes work in competition with macroscopic motions, like rotation-induced
mixing or mass loss, which increase the settling time scales. We have recently
obtained clear evidences that asteroseismology of main sequence solar type
stars can give signatures of the chemical variations inside the stars and help
for a better understanding of these processes.


title: Numerical simulations of self-gravitating magnetized disks

abstract:
  We present the first global simulations of self-gravitating magnetized tori.
The simulations are performed with Zeus-2D and GLOBAL. We find the
magnetorotational instability (MRI) to behave similarly in a self-gravitating
environment as in previous simulations of non self-gravitating systems:
enhancement of turbulent angular momentum transport follows the linear phase.
The torus quickly develops a two component structure composed of an inner thick
disk in Keplerian rotation and an outer massive disk. We compare this result
with zero mass global simulations in 2D, and also present preliminary results
of 3D simulations.


title:
Astrophysical constraints on hypothetical variability of fundamental
  constants

abstract:
  (Abridged) Many-multiplet (MM) method applied to three inhomogeneous samples
of Keck/HIRES quasar absorption spectra gives a shift in the value of the
fine-structure constant of Delta alpha/alpha = (-5.4+/-1.2) 10^{-6} in the
redshift range 0.2 < z < 3.7 (Murphy et al. 2003).The 1sigma error is, however,
much too small and cannot be maintained by current observations of quasars. We
present a modified MM method to set an upper limit on Delta alpha/alpha from a
homogeneous sample of FeII lines identified in the up-to-date best quality
VLT/UVES spectrum of HE 0515-4414. Our result is Delta alpha/alpha =
(1.1+/-1.1) 10^{-5} at z = 1.149. Theoretical models of the fundamental
physical interactions predict that the proton-to-electron mass ratio (mu =
m_p/m_e) may relate to the shift in Delta alpha/alpha as Delta mu/mu = R Delta
alpha/alpha. We use VLT/UVES high-resolution observations of molecular hydrogen
H2 ultraviolet absorption lines at z = 3.025 toward Q 0347-3818 to bound the
value of R. The obtained constraints on Delta ln mu = (2.1+/-3.6) 10^{-5} and
on Delta ln alpha = (1.1+/-1.1) 10^{-5} rule out vary large values of |R| > 6.


title: Satellites of Isolated Elliptical Galaxies

abstract:
  Using well-defined selection criteria applied to the LEDA galaxy catalogue we
have derived a sample of elliptical galaxies that can be classified as
isolated. From this we have investigated the neighbourhood of these galaxies to
determine the frequency and radial distribution of faint galaxies around them
and hence derive an estimate of their surrounding satellite population. The
results are compared and contrasted to the satellite population around isolated
spiral galaxies.


title: X-ray/optical observations of A0535+26/HDE 245770 in quiescence

abstract:
  We present the result of three BeppoSAX observations of the X-ray binary
pulsar A0535+26 in its quiescent state. The source is quite well detected up to
200 keV (6 sigma detection in the stronger observation). No Iron line is
detected in the MECS data (3 sigma upper limit on its equivalent width of 150
eV). There is evidence of a soft excess below 2 keV. Pulsation is detected in
all energy bands up to 10 keV, with a pulsed fraction of ~ 0.5, not varying
with energy. There is a marginal detection (4 sigma) of a cyclotron resonance
feature (CRF) at 118 +/- 20 keV in the PDS spectrum. During the BeppoSAX
observations HDE 245770, the optical counterpart to A0535+26, was monitored
spectroscopically and photometrically. These observations show that the Halpha
and Hbeta lines previously observed in absorption returned in emission,
indicating that the Be disk formed again. The presence of pulsation and a CRF
is a clear indication that accretion onto the polar caps is occurring, and that
the propeller mechanism is leaking. The presence of a soft excess could be
explained either in terms of thermal emission (kT ~ 1.2 keV) from the neutron
star surface, as observed in other accreting X-ray pulsars, or in terms of an
overabundance of Mg in the circumstellar matter.


title:
Particle acceleration in supernova remnants, the Bell-Lucek hypothesis
  and the cosmic ray "knee"

abstract:
  Young supernova remnants are thought to be the sites where cosmic ray
acceleration occurs by the mechanism of diffusive shock acceleration. The
maximum energy gained in this process is conventionally extimated to have a
value close to, but distinctly below, the ``knee'' ($\sim 10^{15}$ eV) of the
cosmic-ray spectrum. Bell & Lucek (2001) have suggested that the generated
cosmic rays simultaneously amplify the magnetic field around the supernova
remnant shock to many times its pre-shock value. In this case the acceleration
rate may be significantly increased and protons can easily reach energies up to
$10^{17}$ eV. We use a ``simplified'' box model incorporating the magnetic
field amplification suggested by Bell & Lucek to investigate the resulting
modifications of the cosmic-ray spectrum. The model predicts a spectral break
at high energies, close to the ``knee'' region, and in good accordance with
observations.


title: KLUN+ peculiar velocity survey

abstract:
  The enhanced Kinematics of the Local Universe (KLUN+) galaxy sample is a
collection of galaxies suitable for Tully-Fisher (TF) or Faber-Jackson (FJ)
distance estimation. Here we extract a subsample of 6229 KLUN+ galaxies closer
than 80 Mpc/h, and calculate their distances and peculiar velocities with the
Iterative Normalized Distance method. Within this method we can derive an
analytical formula, independent from the density inhomogeneities, for
correcting the selection biases. The radial peculiar velocities can then be
derived from the redshifts and the corrected distances. The velocities are
smoothed, and the smoothed velocity field is used as a correction term at the
next derivation of normalized distances. This iterative procedure is repeated
until converging values are reached. Here we present the resulting map of the
radial peculiar velocity field at the < 80 Mpc/h environment. The infall
patterns towards the main galaxy clusters are clearly visible. The color
version of the map, other figures, and animations are provided on the project
web site.


title:
Three-component modeling of C-rich AGB star winds III. Micro-physics of
  drift-dependent dust formation

abstract:
  A proper treatment of the non-equilibrium dust formation process is crucial
in models of AGB star winds. In this paper the micro-physics of this process is
treated in detail, with an emphasis on the effects of drift (drift models). We
summarize the description of the dust formation process and make a few
additions to previous work. A detailed study shows that different growth
species dominate the grain growth rates at different drift velocities. The new
models show that the net effect of drift is to significantly increase the
amounts of dust, seemingly without affecting the mean wind properties, such as
e.g., the mass loss rate. In some cases there is several times more dust in
drift models, compared to the values in the corresponding non-drift models. We
study the formation of a dust shell in the inner parts of the wind and find
that drift plays an active role in accumulating dust to certain narrow regions.
In view of the results presented here it is questionable if drift -- under the
current assumptions -- can be ignored in the grain growth rates.


title: Errors in equations for galaxy rotation speeds

abstract:
  Shown are the errors and difficulties of the equations used for galaxy
rotation speeds in the book "Galactic Dynamics" (Binney and Tremaine). A usable
and accurate set of equations is then presented. The new equations allow easy
determination of galaxy mass distribution from the rotation profile with no
need for dark matter or any knowledge of galaxy surface light.


title:
Hypernovae/GRB in the Galactic Center as possible sources of Galactic
  Positrons

abstract:
  The observation of a strong and extended positron-electron line annihilation
emission in the central regions of the Galaxy by INTEGRAL-SPI, consistent with
the Galactic bulge geometry, without any counterpart in the gamma-ray range,
neither at high energy nor in the 1809 keV $^{26}$Al decay line, is
challenging. Leaving aside the geometrical question, we address the problem of
the adequate positron sources, showing the potentiality of a new category of SN
Ic, exemplified by SN2003dh, which is associated to a gamma-ray burst. This
kind of supernova/hypernova/GRB event is interpreted as the result of a bipolar
Wolf-Rayet explosion, which produces a large amount of $^{56}$Ni and ejects it
at high velocity along the rotation axis. The bulk of positrons resulting from
$^{56}$Co decay escapes in the surrounding medium due to the rapid thinning of
the ejecta in the polar direction. We show that a rate of about 0.02
SN2003dh-like events per century in the central region of the Galaxy is
sufficient to explain the positron flux detected by INTEGRAL-SPI. In order to
explain this flux by SN Ia events alone, a rate of 0.5 per century is
necessary, much higher than indicated by Galactic evolutionary models applied
to the bulge. Further observations of late light curves of SNe Ia and SNe Ic in
the bulge of spiral galaxies, together with 3D hydrodynamic calculations of
anisotropic ejections of $^{56}$Ni in SN Ic/GRB events, will allow to estimate
the separate contributions of SNe Ia and SNe Ic to positron injection.


title: First Planet Confirmation with a Dispersed Fixed-Delay Interferometer

abstract:
  The Exoplanet Tracker is a prototype of a new type of fibre-fed instrument
for performing high precision relative Doppler measurements to detect
extra-solar planets. A combination of Michelson interferometer and medium
resolution spectrograph, this low-cost instrument facilitates radial velocity
measurements with high throughput over a small bandwidth (~ 300 Angstroms), and
has the potential to be designed for multi-object operation with moderate
bandwidths (~1000 Angstroms). We present the first planet detection with this
new type of instrument, a successful confirmation of the well established
planetary companion to 51 Peg, showing an rms precision of 11.5m/s over five
days. We also show comparison measurements of the radial velocity stable star,
Eta Cas, showing an rms precision of 7.9m/s over seven days. These new results
are starting to approach the precision levels obtained with traditional radial
velocity techniques based on cross-dispersed echelles. We anticipate that this
new technique could have an important impact in the search for extra-solar
planets.


title: Quasar Apparent Proper Motion Observed by Geodetic VLBI Networks

abstract:
  In our standard geodetic VLBI solutions, we estimate the positions of quasars
assuming that their positions do not vary in time. However, in solutions
estimating proper motion, a significant number of quasars show apparent proper
motion greater than 50 uas/yr. For individual quasars, there are source
structure effects that cause apparent proper motion. To examine how coherent
the pattern of apparent proper motion is over the sky, we have estimated the
vector spherical harmonic components of the observed proper motion using VLBI
data from 1980 to 2002. We discuss the physical interpretation of the estimated
harmonic components.


title: Halo Substructure in the QUEST RR Lyrae Survey

abstract:
  A survey of 380 sq. deg. of the sky with the 1m Schmidt telescope at the
Observatorio Nacional de Llano del Halo and the QUEST camera has found 498 RR
Lyrae variables lying from 4 to 60 kpc from the Sun. We describe the halo
substructure revealed by these data and the results of measuring some of the
stars' radial velocities and metal abundances.


title: The Impact of Star Formation on Cool Core Galaxy Clusters

abstract:
  We present results from recent simulations of the formation and evolution of
clusters of galaxies in a LambdaCDM cosmology. These simulations contain our
most physically complete input physics to date including radiative cooling,
star formation that transforms rapidly cooling material into aggregate star
particles and we also model the thermal feedback from resulting supernovae in
the star particles. We use an adaptive mesh refinement (AMR) Eulerian
hydrodynamics scheme to obtain very high spatial resolution (~ 2 kpc) in a
computational volume 256 Mpc on a side with mass resolution for dark matter and
star particles of ~ 10^8 M_solar. We examine in detail the appearance and
evolution of the core region of our simulated clusters.


title:
Simulating star formation in molecular cloud cores I. The influence of
  low levels of turbulence on fragmentation and multiplicity

abstract:
  We present the results of an ensemble of simulations of the collapse and
fragmentation of dense star-forming cores. We show that even with very low
levels of turbulence the outcome is usually a binary, or higher-order multiple,
system. We take as the initial conditions for these simulations a typical
low-mass core, based on the average properties of a large sample of observed
cores. All the simulated cores start with a mass of $M = 5.4 M_{\odot}$, a
flattened central density profile, a ratio of thermal to gravitational energy
$\alpha_{\rm therm} = 0.45$ and a ratio of turbulent to gravitational energy
$\alpha_{\rm turb} = 0.05 $. Even this low level of turbulence is sufficient to
produce multiple star formation in 80% of the cores; the mean number of stars
and brown dwarfs formed from a single core is 4.55, and the maximum is 10. At
the outset, the cores have no large-scale rotation. The only difference between
each individual simulation is the detailed structure of the turbulent velocity
field. The multiple systems formed in the simulations have properties
consistent with observed multiple systems. Dynamical evolution tends
preferentially to eject lower mass stars and brown dwarves whilst hardening the
remaining binaries so that the median semi-major axis of binaries formed is
$\sim 30$ au. Ejected objects are usually single low-mass stars and brown
dwarfs, yielding a strong correlation between mass and multiplicity. Our
simulations suggest a natural mechanism for forming binary stars that does not
require large-scale rotation, capture, or large amounts of turbulence.


title: Seismic tests of accretion in central stars of planetary systems

abstract:
  Central stars of extra-solar planetary systems are metal-rich. Planet
accretion or initial surmetallicity can explain this observationnal fact. These
scenarios can be tested with asteroseismology. We calibrate two stellar models,
one with accretion and one with high initial metallicity, in order to obtain
the same external parameters for both of them. We then compare their internal
structures and their oscillation frequencies.


title: Migale : A Multiparametric Virtual Instrument to Study Galaxy Evolution

abstract:
  Galaxy evolution is a complex process where both the inner evolution of
stellar population, gas and dust, and the external effects, like interactions
and exchanges with the environment, have to be taken into account. It has been
fundamental in the last years to be able to build and use homogeneous
catalogues both in the local and the far universe. The observation of galaxy
morphology and kinematics as a function of the redshift is indeed necessary to
disentangle the various galaxy formation and evolution scenarios. Some years
ago, the hyperleda extragalactic database was designed to study the local
universe from the point of view of both stellar populations and galaxies
kinematics and dynamics. Today it contains homogeneous data for about 3
millions of galaxies, with for each up to 80 astrophysical parameters
available. We will describe here the MIGALE project which emcompasses the
HyperLeda databases plus a series of tools developed to study the dynamical,
chemical and morphological evolution of galaxies. It will include, in
particular, methods to analyse the GIRAFFE cosmological fields (IFU
spectroscopy) and compare them with the Local Universe.


title:
Relativistic emission lines from accreting black holes - The effect of
  disk truncation on line profiles

abstract:
  Relativistic emission lines generated by thin accretion disks around rotating
black holes are an important diagnostic tool for testing gravity near the
horizon. The iron K-line is of special importance for the interpretation of the
X-ray emission of Seyfert galaxies, quasars and galactic X-ray binary systems.
A generalized kinematic model is presented which includes radial drifts and
non-Keplerian rotations for the line emitters. The resulting line profiles are
obtained with an object-oriented ray tracer operating in the curved Kerr
background metric. The general form of the Doppler factor is presented which
includes all kinds of poloidal and toroidal motions near the horizon. The
parameters of the model include the spin parameter, the inclination, the
truncation and outer radius of the disk, velocity profiles for rotation and
radial drift, the emissivity profile and a multi-species line-system. The red
wing flux is generally reduced when radial drift is included as compared to the
pure Keplerian velocity field. All resulting emission line profiles can be
classified as triangular, double-horned, double-peaked, bumpy and
shoulder-like. Of particular interest are emission line profiles generated by
truncated standard accretion disks (TSD). It is also shown that the emissivity
law has a great influence on the profiles. The characteristic shoulder-like
line profile observed for the Seyfert galaxy MCG-6-30-15 can be reproduced for
suitable parameters


title:
Towards Gravitational Wave Signals from Realistic Core Collapse
  Supernova Models

abstract:
  We have computed the gravitational wave signal from supernova core collapse
using the presently most realistic input physics available. We start from
state-of-the-art progenitor models of rotating and non-rotating massive stars,
and simulate the dynamics of their core collapse by integrating the equations
of axisymmetric hydrodynamics together with the Boltzmann equation for the
neutrino transport including an elaborate description of neutrino interactions,
and a realistic equation of state. We compute the quadrupole wave amplitudes,
the Fourier wave spectra, the amount of energy radiated in form of
gravitational waves, and the S/N ratios for the LIGO and the tuned Advanced
LIGO interferometers resulting both from non-radial mass motion and anisotropic
neutrino emission. The simulations demonstrate that the dominant contribution
to the gravitational wave signal is produced by neutrino-driven convection
behind the supernova shock. For stellar cores rotating at the extreme of
current stellar evolution predictions, the core-bounce signal is detectable
with advanced LIGO up to a distance of 5kpc, whereas the signal from post-shock
convection is observable up to a distance of about 100kpc. If the core is
non-rotating its gravitational wave emission can be measured up to a distance
of 15kpc, while the signal from the Ledoux convection in the deleptonizing,
nascent neutron star can be detected up to a distance of 10kpc. Both kinds of
signals are generically produced by convection in any core collapse supernova.


title: Constraints on inflation in closed universe

abstract:
  We investigate inflation in closed Friedmann-Robertson-Walker universe filled
with the scalar field with power-law potential. For a wide range of powers and
parameters of the potential we numerically calculated the slow-roll parameters
and scalar spectral index at the epoch when present Hubble scale leaves the
horizon and at the end of inflation. Also we compare results of our numerical
calculations with recent observation data. This allows us to set a constraint
on the power of the potential: alpha < (3.5 - 4.5).


title: Observable Properties of Cosmological Reionization Sources

abstract:
  Motivated by recent evidence that the epoch of reionization of hydrogen may
have ended at a redshift as low as z~6 we consider the detectability of the
sources responsible for this reionization. The main idea is that reionization
places limits on the mean surface brightness of the population of reionization
sources. Reducing the number of model-dependent assumptions to a minimum, we
discuss the observability of these sources with existing and planned
telescopes. We define a family of models characterized by two parameters: the
Lyman continuum escape fraction f_c from the sources, and the clumpiness
parameter C of the intergalactic medium. The minimum surface brightness model
corresponds to a value of unity for both parameters. We find that the detection
of the non-ionizing UV continuum of the reionization sources will be difficult
to accomplish before the launch of JWST if these sources have a mean surface
brightness close to the minimum value. However, if the values of f_c and C are
more realistic, the reionization sources may well be detected by HST before
JWST, perhaps by exploiting gravitational lensing amplification by foreground
clusters of galaxies. Instead of a detection in the continuum, one may attempt
to detect the Lyalpha emission line by narrow-band imaging. Present Lyalpha
searches at z>6 suggest that either the typical sources are fainter than dwarf
galaxies, or that the escape fraction of ionizing photons is much higher than
50%, so that there are no bright compact HII regions formed around the ionizing
sources.


title:
On the Formation of Cool, Non-Flowing Cores in Galaxy Clusters via
  Hierarchical Mergers

abstract:
  We present a new model for the creation of cool cores in rich galaxy clusters
within a LambdaCDM cosmological framework using the results from high spatial
dynamic range, adaptive mesh hydro/N-body simulations. It is proposed that
cores of cool gas first form in subclusters and these subclusters merge to
create rich clusters with cool, central X-Ray excesses. The rich cool clusters
do not possess ``cooling flows'' due to the presence of bulk velocities in the
intracluster medium in excess of 1000 km/sec produced by on-going accretion of
gas from supercluster filaments. This new model has several attractive features
including the presence of substantial core substructure within the cool cores,
and it predicts the appearance of cool bullets, cool fronts, and cool filaments
all of which have been recently observed with X-Ray satellites. This
hierarchical formation model is also consistent with the observation that cool
cores in Abell clusters occur preferentially in dense supercluster
environments. On the other hand, our simulations overproduce cool cores in
virtually all of our numerical clusters, the central densities are high, and
physical core temperatures are often below 1 keV (in contrast to recent
observations). We will discuss additional preliminary simulations to ``soften''
the cool cores involving star formation and supernova feedback.


title:
Mass Modeling of Disk Galaxies: Constraints, Degeneracies and Adiabatic
  Contraction

abstract:
  This paper addresses available constraints on mass models fitted to rotation
curves. Mass models of disk galaxies have well-known degeneracies, that prevent
a unique mass decomposition. The most notable is due to the unknown value of
the stellar mass-to-light ratio (the disk-halo degeneracy); even with this
known, degeneracies between the halo parameters themselves may prevent an
unambiguous determination of the shape of the dark halo profile, which includes
the inner density slope of the dark matter halo. The latter is often referred
to as the ``cusp-core degeneracy''. We explore constraints on the disk and halo
parameters and apply these to four mock and six observed disk galaxies with
high resolution and extended rotation curves. Our full set of constraints
consists of mass-to-light (M/L) ratios from stellar population synthesis models
based on B-R colors, constraints on halo parameters from N-body simulations,
and constraining the halo virial velocity to be less than the maximum observed
velocity. These constraints are only partially successful in lifting the
cusp-core degeneracy. The effect of adiabatic contraction of the halo by the
disk is to steepen cores into cusps and reduce the best-fit halo concentration
and M/L values (often significantly). We also discuss the effect of disk
thickness, halo flattening, distance errors, and rotation curve error values on
mass modeling. Increasing the imposed minimum rotation curve error from
typically low, underestimated values to more realistic estimates decreases the
chi-square substantially and makes distinguishing between a cuspy or cored halo
profile even more difficult. In spite of the degeneracies and uncertainties
present, our constrained mass modeling favors sub-maximal disks (i.e., a
dominant halo) at 2.2 disk scale lengths, with Vdisk/Vtot < 0.6.


title: Axisymmetric MHD simulations of the collapsar model for gamma-ray bursts

abstract:
  We present results from axisymmetric, time-dependent magnetohydrodynamic
(MHD) simulations of the collapsar model for gamma-ray bursts. We begin the
simulations after the 1.7 MSUN iron core of a 25 MSUN presupernova star has
collapsed and study the ensuing accretion of the 7 MSUN helium envelope onto
the central black hole formed by the collapsed iron core. We consider a
spherically symmetric progenitor model, but with spherical symmetry broken by
the introduction of a small, latitude-dependent angular momentum and a weak
radial magnetic field. Our MHD simulations include a realistic equation of
state, neutrino cooling, photodisintegration of helium, and resistive heating.
Our main conclusion is that, within the collapsar model, MHD effects alone are
able to launch, accelerate and sustain a strong polar outflow. We also find
that the outflow is Poynting flux-dominated, and note that this provides
favorable initial conditions for the subsequent production of a baryon-poor
fireball.


title:
Simulations of core convection in rotating A-type stars: Differential
  rotation and overshooting

abstract:
  We present the results of 3--D simulations of core convection within A-type
stars of 2 solar masses, at a range of rotation rates. We consider the inner
30% by radius of such stars, thereby encompassing the convective core and some
of the surrounding radiative envelope. We utilize our anelastic spherical
harmonic (ASH) code, which solves the compressible Navier-Stokes equations in
the anelastic approximation, to examine highly nonlinear flows that can span
multiple scale heights. The cores of these stars are found to rotate
differentially, with central cylindrical regions of strikingly slow rotation
achieved in our simulations of stars whose convective Rossby number (R_{oc}) is
less than unity. Such differential rotation results from the redistribution of
angular momentum by the nonlinear convection that strongly senses the overall
rotation of the star. Penetrative convective motions extend into the overlying
radiative zone, yielding a prolate shape (aligned with the rotation axis) to
the central region in which nearly adiabatic stratification is achieved. This
is further surrounded by a region of overshooting motions, the extent of which
is greater at the equator than at the poles, yielding an overall spherical
shape to the domain experiencing at least some convective mixing. We assess the
overshooting achieved as the stability of the radiative exterior is varied, and
the weak circulations that result in that exterior. The convective plumes serve
to excite gravity waves in the radiative envelope, ranging from localized
ripples of many scales to some remarkable global resonances.


title: Constraining Multiphase Gas in Cooling Flows

abstract:
  We present a spectral analysis of the central X-ray emission for a sample of
galaxy clusters observed with Chandra. We constrain the quantity of a second
cospatial temperature component using Markov Chain Monte Carlo sampling and
discuss the implications for our understanding of cooling flows.


title: Squeezing MOND into a Cosmological Scenario

abstract:
  Explaining the effects of dark matter using modified gravitational dynamics
(MOND) has for decades been both an intriguing and controversial possibility.
By insisting that the gravitational interaction that accounts for the Newtonian
force also drives cosmic expansion, one may kinematically identify which
cosmologies are compatible with MOND, without explicit reference to the
underlying theory so long as the theory obeys Birkhoff's law. Using this
technique, we are able to self-consistently compute a number of quantities of
cosmological interest. We find that the critical acceleration a_0 must have a
slight source-mass dependence (a_0 ~ M^(1/3)) and that MOND cosmologies are
naturally compatible with observed late-time expansion history and the
contemporary cosmic acceleration. However, cosmologies that can produce enough
density perturbations to account for structure formation are contrived and
fine-tuned. Even then, they may be marginally ruled out by evidence of early (z
\~ 20) reionization.


title: Hubble Space Telescope Observations of Novae in M49

abstract:
  A search for novae in M49 (NGC 4472) has been undertaken with the Hubble
Space Telescope. A 55-day observing campaign in F555W (19 epochs) and F814W
(five epochs) has led to the discovery of nine novae. We find that M49 may be
under-abundant in slow, faint novae relative to the Milky Way and M31. Instead,
the decline rates of the M49 novae are remarkably similar to those of novae in
the LMC. This fact argues against a simple classification of novae in "bulge"
and "disk" sub-classes. We examine the Maximum-Magnitude versus Rate of Decline
(MMRD) relation for novae in M49, finding only marginal agreement with the
Galactic and M31 MMRD relations. A recalibration of the Buscombe-de Vaucouleurs
relation gives an absolute magnitude 15 days past maximum of M_{V,15} =
-6.36+/-0.19, which is substantially brighter than previous calibrations based
on Galactic novae. Monte Carlo simulations yield a global nova rate for M49 of
100{+35}{-30} per year, and a luminosity-specific nova rate in the range \nu_K
= 1.7-2.5 per year per 10^{-10} L_K,solar. These rates are far lower than those
predicted by current models of nova production in elliptical galaxies and may
point to a relative scarity of novae progenitors, or an increased recurrence
timescale, in early-type environments.


title: Strings in the Eta Carinae Nebula: Hypersonic Radiative Cosmic Bullets

abstract:
  We present the results of a numerical study focusing on the propagation of a
hypersonic bullet subject to radiative cooling. Our goal is to explore the
feasibility of such a model for the formation of ``strings'' observed in the
Eta Carinae Homunculus nebula. Our simulations were performed in cylindrical
symmetry with the adaptive mesh refinement code AstroBEAR. The radiative
cooling of the system was followed using the cooling curve by Dalgarno & McCray
(1972). In this letter we discuss the evolution and overall morphology of the
system as well as key kinematic properties. We find that radiative bullets can
produce structures with properties similar to those of the Eta Carinae strings,
i.e. high length-to-width ratios and Hubble-type flows in the form of a linear
velocity increase from the base of the wake to the bullet head. These features,
along with the appearance of periodic ``ring-like'' structures, may also make
this model applicable to other astrophysical systems such as planetary nebulae,
e.g. CRL 618 and NGC 6543, young stellar objects, etc.


title: High Resolution X-ray Spectroscopic Constraints on Cooling-Flow Models

abstract:
  We present XMM-Newton Reflection Grating Spectrometer observations of X-ray
clusters and groups of galaxies. We demonstrate the failure of the standard
cooling-flow model to describe the soft X-ray spectrum of clusters of galaxies.
We also emphasize several new developments in the study of the soft X-ray
spectrum of cooling flows. Although there is some uncertainty in the expected
mass deposition rate for any individual cluster, we show that high resolution
RGS spectra robustly demonstrate that the expected line emission from the
isobaric cooling-flow model is absent below 1/3 of the background temperature
rather than below a fixed temperature in all clusters. Furthermore, we
demonstrate that the best-resolved cluster spectra are inconsistent with the
predicted shape of the differential luminosity distribution and the measured
distribution is tilted to higher temperatures. These observations create
several fine-tuning challenges for current theoretical explanations for the
soft X-ray cooling-flow problem. Comparisons between these observations and
other X-ray measurements are discussed.


title: Weak lensing mass distributions for 24 X-Ray Abell Clusters

abstract:
  We use the weak gravitational lensing effect to study the mass distribution
and dynamical state of a sample of 24 X-ray luminous clusters of galaxies
($0.05<z<0.31$) observed with the VLT-FORS1 under homogeneous sky conditions
and subarsecond image quality. The galaxy shapes were measured after
deconvolution with a locally determined point-spread-function, while the
two-dimensional mass distributions of the clusters were computed using an
algorithm based on the maximum entropy method. By comparing the mass and light
distributions of the clusters in our sample, we find that their mass centers,
for the majority of the clusters, is consistent with the positions of optical
centers. We find that some clusters present significant mass substructures
which generally have optical counterparts. At least in one cluster (Abell
1451), we detect a mass substructure without an obvious luminous counterpart.
The radial profile of the shear of the clusters was fitted using circular and
elliptical isothermal elliptical distributions, which allowed the finding of a
strong correlation between the orientation of the major-axis of the matter
distribution and the corresponding major-axes of the brightest cluster galaxy
light-profiles. Estimates of how close to dynamical relaxation are these
clusters were obtained through comparison of our weak-lensing mass measurements
with the x-ray and velocity dispersion determinations available in the
literature. We find that clusters with intra-cluster gas colder than 8 keV show
a good agreement between the different mass determinations, but clusters with
gas hotter than 8 keV present discrepant mass values.


title:
Gas Dynamical Simulations of the Large and Little Homunculus Nebulae of
  Eta Carinae

abstract:
  We here present two-dimensional, time-dependent radiatively cooling
hydrodynamical simulations of the large and little Homunculus nebulae around
$\eta$ Carinae. We employ an alternative scenario to previous interacting
stellar wind models which is supported by both theoretical and observational
evidence, where a non-spherical outburst wind (with a latitudinal velocity
dependence that matches the observations of the large Homunculus), which is
expelled for 20 years, interacts with a pre-eruptive slow wind also with a
toroidal density distribution, but with a much smaller equator-to-polar density
contrast than that assumed in previous models. A second eruptive wind with
spherical shape is ejected about 50 years after the first outburst, and causes
the development of the little internal nebula. We find that, as a result of an
appropriate combination of the parameters that control the degree of asymmetry
of the interacting winds, we are able to produce not only the structure and
kinematics of both Homunculus, but also the high-velocity equatorial ejecta.
These arise from the impact between the non-spherical outburst and the
pre-outburst winds in the equatorial plane.


title: Radio Galaxies in Cooling Cores

abstract:
  A currently active radio galaxy sits at the center of almost every strong
cooling core. What effect does it have on the cooling core? Could its effect be
strong enough to offset the radiative cooling which should be occuring in these
cores? In order to answer these questions we need to know how much energy the
radio jet carries to the cooling core; but we have no way to measure the jet
power directly. We therefore need to understand how the radio source evolves
with time, and how it radiates, in order to use the data to determine the jet
power. When some simple models are compared to the data, we learn that
cluster-center radio galaxies probably are energetically important -- but not
necessarily dominant -- in cooling cores.


title: Evidence for bipolar jets in late stages of AGB winds

abstract:
  Bipolar expansion at various stages of evolution has been recently observed
in a number of AGB stars. The expansion is driven by bipolar jets that emerge
late in the evolution of AGB winds. The wind traps the jets, resulting in an
expanding, elongated cocoon. Eventually the jets break-out from the confining
spherical wind, as recently observed in W43A. This source displays the most
advanced evolutionary stage of jets in AGB winds. The earliest example is
IRC+10011, where the asymmetry is revealed in high-resolution near-IR imaging.
In this source the jets turned on only ~200 years ago, while the spherical wind
is ~4000 years old.


title: Gravitational Lensing Statistics in Universes Dominated by Dark Energy

abstract:
  We study lens statistics in flat, low-density universes with different
equations of state $w=p_Q/\rho_Q$ for the dark energy component. Dark energy
modifies the distance-redshift relation and the mass function of dark matter
halos leading to changes in the lensing optical depth as a function of image
separation. Those effects must, however, be distinguished from effects
associated with the structure of dark matter halos. Baryonic cooling causes
galaxy-mass halos to have different central density profiles than group- and
cluster-mass halos, which causes the distribution of normal arcsecond-scale
lenses to differ from the distribution of ``wide-separation'' ($\Delta\theta
\gtrsim 4\arcsec$) lenses. Fortunately, the various parameters related to
cosmology and halo structure have very different effects on the overall image
separation distribution: (1) the abundance of wide-separation lenses is
exremely sensitive (by orders of magnitude) to the distribution of
``concentration'' parameters for massive halos modeled with the
Navarro-Frenk-White profile; (2) the transition between normal and
wide-separation lenses depends mainly on the mass scale where baryonic cooling
ceases to be efficient; and (3) dark energy has effects at all image separation
scales. While current lens samples cannot usefully constrain all of the
parameters, ongoing and future imaging surveys should discover hundreds or
thousands of lenses and make it possible to disentangle the various effects and
constrain all of the parameters simultaneously. (abridged)


title:
Spectra from Forming Region of the First Galaxies : The Effect of
  Aspherical Deceleration

abstract:
  Ly$\alpha$ line emission from the Loeb-Rybicki (LR) halo, which is the
expanding HI IGM (intergalactic medium) around the first star clusters and the
ionized interstellar medium, is investigated by solving a radiative transfer
problem. While the initial scattering optical depth is $\sim 10^5$ for the
Ly$\alpha$ photons, most of the Ly$\alpha$ photons can escape when the
cumulative frequency-shift due to the expansion of the HI IGM becomes
significantly large. The current paper improves upon previous treatments of the
scattering processes and the opacity for the Ly$\alpha$ transfer. Confirming
the previous results of the LR halo, we investigate the effect of the
aspherical expansion of the IGM. The asphericity is hypothesized to follow the
initial stage of the gravitational deceleration to form the large scale
filamentary structure of the Universe. According to our results, the effect of
the asphericity lets the peak wavelength of the line profile shift to longer
wavelengths and the FWHM of the profile become wider than those of the
spherically expanding model. To detect these features is meaningful if we are
interested in the initial evolution of the large scale structure, since they
reflect the dynamical properties of the IGM at that time. Furthermore, given
the recent discovery of the high redshift cosmological reionization, we briefly
comment on the effects of the redshift and the cosmological parameters on the
line profile.


title: Observed and physical properties of type II plateau supernovae

abstract:
  I use photometry and spectroscopy data for 24 Type II plateau supernovae to
examine their observed and physical properties. This dataset shows that these
objects encompass a wide range in their observed properties (plateau
luminosities, tail luminosities, and expansion velocities) and their physical
parameters (explosion energies, ejected masses, initial radii, and 56Ni
yields). Several regularities emerge within this diversity, which reveal (1) a
continuum in the properties of Type II plateau supernovae, (2) a one parameter
family (at least to first order), (3) evidence that stellar mass plays a
central role in the physics of core collapse and the fate of massive stars.


title: The DIRECT Project

abstract:
  The DIRECT project aims to determine direct distances to two important
galaxies in the cosmological distance ladder -- M31 and M33 -- using detached
eclipsing binaries (DEBs) and Cepheids. I present an overview of the project
and some results from follow-up observations.


title: General Relativistic Magnetohydrodynamic Simulations of Collapsars

abstract:
  We have performed 2.5-dimensional general relativistic magnetohydrodynamic
(MHD) simulations of the gravitational collapse of a magnetized rotating
massive star as a model of gamma ray bursts (GRBs). The current calculation
focuses on general relativistic MHD with simplified microphysics (we ignore
neutrino cooling, physical equation of state, and photodisintegration).
Initially, we assume that the core collapse has failed in this star. A few
$M_{\odot}$ black hole is inserted by hand into the calculation. The
simulations presented in the paper follow the accretion of gas into a black
hole that is assumed to have formed before the calculation begins.The
simulation results show the formation of a disk-like structure and the
generation of a jetlike outflow inside the shock wave launched at the core
bounce. We have found that the jet is accelerated by the magnetic pressure and
the centrifugal force and is collimated by the pinching force of the toroidal
magnetic field amplified by the rotation and the effect of geometry of the
poloidal magnetic field. The maximum velocity of the jet is mildly relativistic
(0.3c). The velocity of the jet becomes larger as the initial rotational
velocity of stellar matter gets faster. On the other hand, the dependence on
the initial magnetic field strength is a bit more complicated: the velocity of
the jet increases with the initial field strength in the weak field regime,
then is saturated at some intermediate field strength, and decreases beyond the
critical field strength. These results are related to the stored magnetic
energy determined by the balance between the propagation time of the Alfven
wave and the rotation time of the disk (or twisting time).


title: Technetium and the third dredge up in AGB stars. I. Field stars

abstract:
  We searched for Tc in a sample of long period variables selected by stellar
luminosity derived from Hipparcos parallaxes. Tc, as an unstable s-process
element, is a good indicator for the evolutionary status of stars on the
asymptotic giant branch (AGB). In this paper we study the occurrence of Tc as a
function of luminosity to provide constraints on the minimum luminosity for the
third dredge up as estimated from recent stellar evolution models.
  A large number of AGB stars above the estimated theoretical limit for the
third dredge up are found not to show Tc. We confirm previous findings that
only a small fraction of the semiregular variables show Tc lines in their
spectra. Contrary to earlier results by Little et al. (1987) we find also a
significant number of Miras without Tc.
  The presence and absence of Tc is discussed in relation to the mass
distribution of AGB stars. We find that a large fraction of the stars of our
sample must have current masses of less than 1.5 M_{\sun}. Combining our
findings with stellar evolution scenarios we conclude that the fraction of time
a star is observed as a SRV or a Mira is dependent on its mass.


title: Extending the Butcher--Oemler effect up to z~0.7

abstract:
  We have observed three clusters at z~0.7, of richness comparable to the low
redshift sample of Butcher & Oemler (BO), and determined their fraction of blue
galaxies. When adopting the standard error definition, two clusters have a low
blue fraction for their redshifts, whereas the fraction of the third one is
compatible with the expected value. A detailed analysis of previous BO-like
studies that adopted different definitions of the blue fraction shows that the
modified definitions are affected by contaminating signals: colour segregation
in clusters affects blue fractions derived in fixed metric apertures,
differential evolution of early and late type spirals potentially affects blue
fractions derived with a non standard choice of the colour cut, the younger age
of the Universe at high redshift affects blue fractions computed with a colour
cut taken relatively to a fixed non evolving colour. Adopting these definitions
we find largely varying blue fractions. This thorough analysis of the drawbacks
of the different possible definitions of the blue fraction should allow future
studies to perform measures in the same scale. Finally, if one adopts a more
refined error analysis to deal with BO and our data, a constant blue fraction
with redshift cannot be excluded, showing that the BO effect is still far from
being detected beyond doubt.


title:
Collapse of Rotating Supramassive Neutron Stars to Black Holes: Fully
  General Relativistic Simulations

abstract:
  We study the final state of the gravitational collapse of uniformly rotating
supramassive neutron stars by axisymmetric simulations in full general
relativity. The rotating stars provided as the initial condition are marginally
stable against quasiradial gravitational collapse and its equatorial radius
rotates with the Kepler velocity (i.e., the star is at the mass-shedding
limit). To model the neutron stars, we adopt the polytropic equations of state
for a wide range of the polytropic index as $n=2/3$, 4/5, 1, 3/2 and 2. We
follow the formation and evolution of the black holes, and show that
irrespective of the value of $n (2/3\leq n \leq 2)$, the final state is a Kerr
black hole and the disk mass is very small ($< 10^{-3}$ of the initial stellar
mass).


title: Magnetically driven outflows from Jovian circum-planetaryaccretion disks

abstract:
  We discuss the possibility to launch outflows from the close vicinity of a
protoplanetary core considering a scenario where the protoplanet surrounded by
a circum-planetary accretion disk is located in a circum-stellar disk. For the
circum-planetary disk accretion rate we assume 6x10^{-5} M_jup/yr, implying
peak disk temperatures of about 2000K. The estimated disk ionization degree and
Reynolds number allow for a sufficient coupling between the disk matter and the
magnetic field. We find that the surface magnetic field strength of the
protoplanet is probably not more than 10 G, indicating that the global
planetary magnetosphere is dominated by the circum-planetary disk magnetic
field below 50 G. The estimated field strength and mass flow rates allow for
asymptotic outflow velocities of 60 km/s. The overall outflow geometry will
resemble a hollow tube or cone perpendicular the disk. Outflows from
circum-planetary disks may be visible in shock excited emission lines along a
tube of diameter of the orbital radius and thickness of about 100
protoplanetary radii. Energetically, protoplanetary outflows cannot survive the
interaction with a protostellar outflow. Due to the efficient angular momentum
removal by the outflow, we expect the protoplanetary outflow to influence the
early planet angular momentum evolution.


title: An active M8.5 dwarf wide companion to the M4/DA binary LHS4039/LHS4040

abstract:
  Low-mass and brown dwarfs have recently been found as wide companions to many
nearby stars, formerly believed to be single. Wide binaries are usually found
as common proper motion pairs. Sometimes, more than two objects share the same
large proper motion, identifying them as nearby systems. We have found a third,
low-mass component to a known wide binary at a distance of about 21pc,
consisting of a red and a white dwarf (LHS4039 and LHS4040; about 150AU
separation). The new companion, APMPMJ2354-3316C separated by about 2200AU, was
classified as M8.5 dwarf. In recent spectroscopic observations it shows a very
strong $H_{\alpha}$ emission line and blue continuum. Comparing this event to
flares in late-type M dwarfs, we find some similarity with LHS2397a, a nearby
M8 dwarf which is so far the only known example of a low-mass star with a tight
brown dwarf companion (separation of less than 4AU). The level of the activity
as measured by $L_{H_{\alpha}}/L_{bol}$ is comparable to that of the M9.5 dwarf
2MASSWJ0149+29 both during the flare and in quiescence.


title: Doppler-like effect and doubtful expansion of universe

abstract:
  The distance contraction, as observed in electrical soundings over
horizontally stratified earth (static system), is identified as a counterpart
of Doppler shift in dynamical systems. Identification of Doppler-like effect in
a stock-still systems makes it possible to give an al-ternative answer to the
question about an effective cause of the Doppler shift, which sounds: the
inhomogeneities. This answer opens different static as well as kinematic
possibilities, which challenge established theories of expanding universe and
energizing big bang.The energy propagating in stratified universe of layers
exhibits a shift which could be at-tributed not only to the expansion (Hubble's
theory) but alternatively to fluctuations in material properties
(inhomogeneities).


title: The UV luminosity function of nearby clusters of galaxies

abstract:
  We present the UV composite luminosity function for galaxies in the Virgo,
Coma and Abell 1367 clusters. The luminosity function (LF) is well fitted by a
Schechter function with M*(UV} - 5*log h(75) = -20.75 +/- 0.40 and alpha =
-1.50 +/- 0.10 and does not differ significantly from the local UV luminosity
function of the field. This result is in agreement with recent studies carried
out in the Halpha and B-bands which find no difference between the LFs of star
forming galaxies in clusters and in the field. This indicates that, whatever
mechanisms are responsible for quenching the star formation in clusters, they
influence similarly the giant and the dwarf populations, leaving the shape of
the LF unchanged and only modifying its normalization.


title:
A new template background estimate for source searching in TeV gamma-ray
  astronomy

abstract:
  A new method is described that permits quickly and easily, a 2-dimensional
search for TeV gamma-ray sources over large fields of view ~6deg with
instruments utilising the imaging atmospheric Cerenkov technique. It employs as
a background estimate, events normally rejected according to a cosmic-ray
background rejection criterion based on image shape, but with reconstructed
directions overlapping the source of interest. This so-called template
background model is demonstrated using example data taken with the stereoscopic
HEGRA System of Cerenkov Telescopes. Discussion includes comparisons with a
conventional background estimate and limitations of the model. The template
model is well suited to the search for point-like, moderately extended sources
and combinations thereof, and compensates well for localised systematic changes
in cosmic-ray background response.


title: Modulation of the X-ray Fluxes by the AEI

abstract:
  The Accretion-Ejection Instability (AEI) has been proposed to explain the low
frequency Quasi-Periodic Oscillation (QPO) observed in low-mass X-Ray Binaries.
Its frequency, typically a fraction of the Keplerian frequency at the disk
inner radius, is in the right range indicated by observations. With numerical
simulation we will show how this instability is able to produce a modulation of
the X-ray flux and what are the characteristic of this modulation. More
simulations are required, especially 3D MHD simulations. We will briefly
present a new code in development: AstroBear which will allow us to create
synthetic spectra.


title: A Complete Sample of Soft X-ray Selected AGN: I. The Data

abstract:
  We present the optical spectra and simple statistical analysis for a complete
sample of 110 soft X-ray selected AGN. About half of the sources are
Narrow-Line Seyfert 1 galaxies (NLS1s), which have the steepest X-ray spectra,
strongest FeII emission and slightly weaker [OIII]5007 emission than broad line
Seyfert 1s (BLS1s).
  Kolmogorov Smirnov tests show that NLS1s and BLS1s have clearly different
distributions of the X-ray spectral slope, X-ray short-term variability, and
FeII equivalent widths and luminosity and FeII/H-beta ratios. The differences
in the [OIII]/H-beta and [OIII] equivalent widths are only marginal. We found
no significant differences between NLS1s and BLS1s in their rest frame 0.2-2.0
X-ray luminosities, rest frame 5100A monochromatic luminosities, bolometric
luminosities, redshifts, and their H$\beta$ equivalent widths.


title: Magnetic fields and cosmic rays in cooling flows

abstract:
  Cooling flows are regions where the importance of non-thermal intra-cluster
medium components such as magnetic fields and cosmic rays may be strongest
within a galaxy cluster. They are also regions where such components are best
detectable due to the high gas density which influences Faraday rotation
measurements of magnetic fields and secondary particle production in hadronic
interactions of cosmic ray nuclei with the ambient thermal gas. New estimates
of magnetic fields in cooling flow and non-cooling flow clusters are presented,
which are based on a newly developed Fourier analysis of extended Faraday
rotation maps. We further present new constraints on the cluster cosmic ray
proton population using radio and gamma-ray observations measurements of
cluster cooling flows, which are especially suited for this purpose due to
their high gas and magnetic energy densities. We argue that radio synchrotron
emission of cosmic ray electrons generated hadronically by cosmic ray protons
is a very plausible explanation for the radio mini-halos observed in some
cooling flows.


title:
Hubble Space Telescope Observations of NGC 6240: a Case Study of an
  Ultra-Luminous Infrared Galaxy with Obscured Activity

abstract:
  We present results from an HST study of the morphology and kinematics of NGC
6240. This merging galaxy with a double nucleus is one of the nearest and
best-studied ultraluminous infrared galaxies. HST resolves both nuclei into
seperate components. The distance between the northern and southern
optical/near-infrared components is greater than that observed in radio and
X-ray studies, arguing that even in K-band we may not be seeing all the way
through the dust to the true nuclei. The ionized gas does not display rotation
around either of the nuclei, or equilibrium motion in general. There is a
strong velocity gradient between the nuclei, similar to what is seen in CO
data. There is no such gradient in our stellar kinematics. The velocity
dispersion of the gas is larger than expected for a cold disk. We also map and
model the emission-line velocity field at an off-nuclear position where a steep
velocity gradient was previously detected in ground-based data. Overall, the
data indicate that line-of-sight projection effects, dust absorption,
non-equilibrium merger dynamics, and the possible influence of a wind may be
playing an important role in the observed kinematics. Chandra observations of
hard X-rays have shown that both of the nuclei contain an Active Galactic
Nucleus (AGN). The HST data show no clear sign of the two AGNs: neither
continuum nor narrow-band imaging shows evidence for unresolved components in
the nuclei, and there are no increased emission line widths or rapid rotation
near the nuclei. This underscores the importance of X-ray data for identifying
AGNs in highly dust-enshrouded environments.


title: Solar Models and Solar Neutrinos

abstract:
  I summarize 40 years of development of the standard solar model that is used
to predict solar neutrino fluxes and then describe the current uncertainties in
the predictions. I will also attempt to explain why it took so long, about
three and a half decades, to reach a consensus view that new physics is being
learned from solar neutrino experiments.


title: On the morphogenesis of stellar flows - Application to planetary nebulae

abstract:
  A large class of stellar systems (e.g., planetary nebulae (PNe), supernova
envelopes, LBV stars, young stars in formation) shows structures in their
accretion/ejection phase that have similar characteristics. In particular, one
currently observes for these objects equatorial discs, axial ejections and
stable bipolar shells. However these simple shapes, which are expected to be
solutions of standard hydrodynamical equations, are not yet fully understood.
In this paper, we suggest a new form of these equations that takes into account
the fractality and the irreversibility of particle motion in such processes.
Then we study in this framework a general infall or ejection motion in a
central spherical potential. From the stationary solutions allowed by this new
hydrodynamical system, we deduce a specific distribution of matter density,
described in terms of probability density for ejection angles. A global
classification of predicted shapes, depending on the values of conservative
quantities such as (E^2,L^2,L_z), is given. These results are compared with the
available observational data, and allows us to theoretically predict the
possible existence of more complicated structures and of correlations between
observable variables, which could be checked by future observations.


title: Coronae of Cool Stars

abstract:
  We present preliminary results of grating observations of YY Mensae and V824
Arae by Chandra and XMM-Newton. Spectral features are presented in the context
of the emission measure distributions, the coronal abundances, and plasma
electron densities. In particular, we observe a coronal N/C enhancement in YY
Men believed to reflect the photospheric composition (CN cycle). Finally, we
interpret line broadening in YY Men as Doppler thermal broadening in its very
hot corona.


title:
The Insignificance of Global Reheating in the Abell 1068 Cluster: X-Ray
  Analysis

abstract:
  We report on a Chandra observation of the massive, medium redshift (z=0.1386)
cooling flow cluster Abell 1068. We detect a clear temperature gradient in the
X-ray emitting gas from kT ~ 5 keV in the outer part of the cluster down to
roughly 2 keV in the core, and a striking increase in the metallicity of the
gas toward the cluster center. The total spectrum from the cluster can be fit
by a cooling flow model with a total mass deposition rate of 150 solar
masses/yr. Within the core (r < 30 kpc), the mass depositon rate of 40 solar
masses/yr is comparable to estimates for the star formation rate from optical
data. We find an apparent correlation between the cD galaxy's optical isophotes
and enhanced metallicity isocontours in the central ~100 kpc of the cluster. We
show that the approximate doubling of the metallicity associated with the cD
can be plausibly explained by supernova explosions associated with the cD's
ambient stellar population and the recent starburst. Finally, we calculate the
amount of heating due to thermal conduction and show that this process is
unlikely to offset cooling in Abell 1068.


title:
On gamma-ray bursts and their biological effects :a case for an
  extrinsic trigger of the Cambrian explosion ?

abstract:
  We discuss some the effects of local gamma-ray bursts on the earth's
atmosphere. A rough calculation of the fraction of ozone destruction by
catalytic $NO_{x}$ cycles is given, which in turn serves to argue how the large
flux of gammas from these events would have indirectly provoked major
extinction of living organisms. We give specific examples of these features,
and tentatively identify the Cambrian explosion seen in the actual fossil
record as an event caused by a GRB.


title:
The Insignificance of Global Reheating in the Abell 1068 Cluster:
  Multiwavelength Analysis

abstract:
  We present a detailed, multiwavelength study of the Abell 1068 galaxy
cluster, and we use this data to test cooling and energy feedback models of
galaxy clusters. Near ultraviolet and infrared images of the cluster show that
the cD galaxy is experiencing star formation at a rate of ~20-70 M_o/yr over
the past ~100 Myr. The dusty starburst is concentrated toward the nucleus of
the cD galaxy and in filamentary structures projecting 60 kpc into its halo.
The Chandra X-ray image presented in WMM reveals a steep temperature gradient
that drops from roughly 4.8 keV beyond 120 kpc to roughly 2.3 keV in the inner
10 kpc of the galaxy where the starburst peaks. Over 95% of the ultraviolet and
Halpha photons associated with the starburst are emerging from regions cloaked
in keV gas with very short cooling times ~100 Myr, as would be expected from
star formation fueled by cooling condensations in the intracluster medium. The
local cooling rate in the vicinity of the central starburst is < 40 M_o/yr,
which is consistent with the star formation rate determined with U-band and
infrared data. We find that energy feedback from both the radio source and
thermal conduction are inconsequential in Abell 1068. Although supernova
explosions associated with the starburst may be able to retard by ~18% or so,
they are incapable of maintaining the cooling gas at keV temperatures.


title: Gravitational structure formation in scale relativity

abstract:
  In the framework of the theory of scale relativity, we suggest a solution to
the cosmological problem of the formation and evolution of gravitational
structures on many scales. This approach is based on the giving up of the
hypothesis of differentiability of space-time coordinates. As a consequence of
this generalization, space-time is not only curved, but also fractal. In
analogy with Einstein's general relativistic methods, we describe the effects
of space fractality on motion by the construction of a covariant derivative.
The principle of equivalence allows us to write the equation of dynamics as a
geodesics equation that takes the form of the equation of free Galilean motion.
Then, after a change of variables, this equation can be integrated in terms of
a gravitational Schrodinger equation that involves a new fundamental
gravitational coupling constant, alpha_{g} = w_{0}/c. Its solutions give
probability densities that quantitatively describe precise morphologies in the
position space and in the velocity space. Finally the theoretical predictions
are successfully checked by a comparison with observational data: we find that
matter is self-organized in accordance with the solutions of the gravitational
Schrodinger equation on the basis of the universal constant w_{0}=144.7 +- 0.7
km/s (and its multiples and sub-multiples), from the scale of our Earth and the
Solar System to large scale structures of the Universe


title:
Photometric study of southern SU UMa-type dwarf novae and candidates --
  III: NSV 10934, MM Sco, AB Nor, CAL 86

abstract:
  We photometrically observed four southern dwarf novae in outburst (NSV 10934,
MM Sco, AB Nor and CAL 86). NSV 10934 was confirmed to be an SU UMa-type dwarf
nova with a mean superhump period of 0.07478(1) d. This star also showed
transient appearance of quasi-periodic oscillations (QPOs) during the final
growing stage of the superhumps. Combined with the recent theoretical
interpretation and with the rather unusual rapid terminal fading of normal
outbursts, NSV 10934 may be a candidate intermediate polar showing SU UMa-type
properties. The mean superhump periods of MM Sco and AB Nor were determined to
be 0.06136(4) d and 0.08438(2) d, respectively. We suggest that AB Nor belongs
to a rather rare class of long-period SU UMa-type dwarf novae with low
mass-transfer rates. We also observed an outburst of the suspected SU UMa-type
dwarf nova CAL 86. We identified this outburst as a normal outburst and
determined the mean decline rate of 1.1 mag/d.


title:
The Canada-France Deep Fields III: Photometric Redshift Distribution to
  I(AB) ~ 24

abstract:
  We compute accurate redshift distributions to I(AB) = 24 and R(AB) = 24.5
using photometric redshifts estimated from six-band UBVRIZ photometry in the
Canada-France Deep Fields-Photometric Redshift Survey (CFDF-PRS). Our
photometric redshift algorithm is calibrated using hundreds of CFRS
spectroscopic redshifts in the same fields. The dispersion in redshift is
\sigma/(1+z) \la 0.04 to the CFRS depth of I(AB) = 22.5, rising to \sigma/(1+z)
\la 0.06 at our nominal magnitude and redshift limits of I(AB) = 24 and z \le
1.3, respectively. We describe a new method to compute N(z) that incorporates
the full redshift likelihood functions in a Bayesian iterative analysis and we
demonstrate in extensive Monte Carlo simulations that it is superior to
distributions calculated using simple maximum likelihood redshifts. The
field-to-field differences in the redshift distributions, while not unexpected
theoretically, are substantial even on 30' scales. We provide I(AB) and R(AB)
redshift distributions, median redshifts, and parametrized fits of our results
in various magnitude ranges, accounting for both random and systematic errors
in the analysis.


title:
Chandra and HST Confirmation of the Luminous and Variable X-ray Source
  IC 10 X-1 as a Possible Wolf-Rayet, Black-Hole Binary

abstract:
  We present a Chandra and HST study of IC 10 X-1, the most luminous X-ray
binary in the closest starburst galaxy to the Milky Way. Our new hard X-ray
observation of X-1 confirms that it has an average 0.5-10 keV luminosity of
1.5e38 erg/s, is strongly variable (a factor of ~2 in >3 ks), and is spatially
coincident (within 0.'23 +/-0.'30) with the Wolf-Rayet (WR) star [MAC92] 17A in
IC 10. The spectrum of X-1 is best fit by a power law with photon index of ~1.8
and a thermal plasma with kT~1.5 keV, although systematic residuals hint at
further complexity. Taken together, these facts suggest that X-1 may be a black
hole belonging to the rare class of WR binaries; it is comparable in many ways
to Cyg X-3. The Chandra observation also finds evidence for extended X-ray
emission co-spatial with the large non-thermal radio superbubble surrounding
X-1.


title: Electromagnetic (versus fireball) model of GRBs

abstract:
  We briefly review the electromagnetic model of Gamma Ray Bursts and then
discuss how various models account for high prompt polarization. We argue that
if polarization is confirmed at a level $\Pi \geq 10%$ the internal shock model
is excluded.


title: On the Detectability of Turbulence and Bulk Flows in X-ray Clusters

abstract:
  Cooling flows, cluster mergers and motions of galaxies through the cluster
gas with supersonic and sonic velocities must lead to large scale motions of
the intracluster medium (ICM). A high-resolution numerical simulation of X-ray
cluster formation by Norman and Bryan predicts cluster-wide turbulence with
v_turb ~ 300-600 ~km/s and eddy scales l_outer ~ 100-500 kpc, the larger
numbers being characteristic of turbulence near the virial radius, while the
smaller numbers pertain to the core. The simulation also predicts the existence
of ordered bulk flows in the core with v ~ 400 km/s on scales of several
hundred kpc. In this paper we consider the observability of such fluid motions
via the distortions it induces in the CMB via the kinematic SZ effect, as well
as via Doppler broadening and shifting of metal lines in the X-ray spectrum. We
estimate |\Delta T/T|_kinematic < few X 10^{-6} -- at or below current limits
of detectability. However, we find that an energy resolution of a few eV is
sufficient to detect several Doppler shifted components in the 6.7 keV Fe line
in the core of the cluster.


title: An Improved RF Cavity Search for Halo Axions

abstract:
  The axion is a hypothetical elementary particle and cold dark matter
candidate. In this RF cavity experiment, halo axions entering a resonant cavity
immersed in a static magnetic field convert into microwave photons, with the
resulting photons detected by a low-noise receiver. The ADMX Collaboration
presents new limits on the axion-to-photon coupling and local axion dark matter
halo mass density from a RF cavity axion search in the axion mass range 1.9-2.3
microeV, broadening the search range to 1.9-3.3 microeV. In addition, we report
first results from an improved analysis technique.


title:
Two New Close Binary Central Stars of Planetary Nebulae from a
  Critically Selected Southern Hemisphere Sample

abstract:
  I present the results of time-resolved photometry of a selection of central
stars of planetary nebulae. The study reveals periodic variability in two of
the eight central stars observed, those of NGC 6026 and NGC 6337. The
variability matches that expected from a binary system in which a hot primary
irradiates a cooler secondary star.


title:
Subaru Deep Spectroscopy of the Very Extended Emission-Line Region of
  NGC 4388: Ram Pressure Stripped Gas Ionized by the Nuclear Radiation

abstract:
  We report here the results of deep optical spectroscopy of the very extended
emission-line region (VEELR) found serendipitously around the Seyfert 2 galaxy
NGC 4388 in the Virgo cluster using the Subaru Telescope. The H-alpha recession
velocities of most of the filaments of the region observed are highly
blue-shifted with respect to the systemic velocity of the galaxy. The velocity
field is complicated, and from the kinematic and morphological points of view,
there seem to be several streams of filaments: low velocity (v = -100 km/s)
filaments, high velocity (v = -300 km/s) filaments, and a very high velocity (v
> -500 km/s) cloud complex. The emission-line ratios of the VEELR filaments are
well explained by power-law photoionization models with solar abundances,
suggesting that the Seyfert nucleus of NGC 4388 is the dominant ionization
source of the VEELR and that the VEELR gas has moderate metallicity. In
addition to photoionization, shock heating probably contributes to the
ionization of the gas. In particular, the filaments outside the ionization cone
of the Seyfert nucleus are mainly excited by shocks. We conclude that the VEELR
was formerly the disk gas of NGC 4388, which has been stripped by ram pressure
due to the interaction between the hot intra-cluster medium (ICM) and the
galaxy. The velocity field and the morphology of the VEELR closely resemble
snapshots from some numerical simulations of this process. In the case of NGC
4388, the ram pressure-stripped gas, which is normally seen as extended HI
filaments, happens to be exposed and ionized by the radiation from the AGN, and
so can be seen as optical emission-line gas.


title:
Double-double radio galaxies: remnants of merger of supermassive binary
  black holes

abstract:
  The activity of active galaxy may be triggered by the merge of galaxies and
present-day galaxies are probably the product of successive minor mergers. The
frequent galactic merges at high redshift imply that active galaxy harbors
supermassive unequal-mass binary black holes in its center at least once during
its life time. In this paper, we showed that the recently discovered
double-lobed FR II radio galaxies are the remnants of such supermassive binary
black holes. The inspiraling secondary black hole opens a gap in the accretion
disk and removes the inner accretion disk when it merges into the primary black
hole, leaving a big hole of about several hundreds of Schwarzschild radius in
the vicinity of the post-merged supermassive black hole and leading to an
interruption of jet formation. When the outer accretion disk slowly refills the
big hole on a viscous time scale, the jet formation restarts and the
interaction of the recurrent jets and the inter-galactic medium forms a
secondary pair of lobes. We applied the model to a particular double-lobed
radio source B1834+620 and showed that the orbit of the secondary is elliptical
with a typical eccentricity $e \simeq 0.68$ and the mass ratio $q$ of the
secondary and the primary is $0.01 \la q \la 0.4$. The accretion disk is a
standard $\alpha$-disk with $0.01 \la \alpha \la 0.04$ and the ratio of disk
half height $H$ and radius $r$ is $\delta \simeq 0.01$. The model predicates
that double-lobed radio structure forms only in FR II radio galaxies.


title: Radio Observations of Masers in Post-AGB Stars

abstract:
  We present observations of 86 post-Asymptotic Giant Branch (post-AGB) stars
of OH maser transitions, taken with the Parkes Telescope between September 2002
and August 2003. Post-AGB stars are the precursors of planetary nebulae, which
have a wide range of morphologies that are not well explained. By studying the
circumstellar envelopes of post-AGB stars through the masers produced in them,
we hope to shed light on the origin of planetary nebula morphologies.


title: Core-Collapse Supernova Mechanism - Importance of Rotation

abstract:
  An attempt is made to assess the significance of rotation in the
core-collapse supernova phenomenon, from both observational and theoretical
point of view. The data on supernovae particularly indicative of the role of
rotation in the collapse-triggered explosion is emphasized. The problem of
including the rotation of presupernova core into the supernova theory is
considered. A two-dimensional classification scheme of core-collapse supernovae
is proposed which unifies 'classical' supernovae of type Ib/c and type II,
'hypernovae' and some GRB events.


title: The very local Hubble flow: computer simulations of dynamical history

abstract:
  The phenomenon of the very local ($\le3$ Mpc) Hubble flow is studied on the
basis of the data of recent precision observations. A set of computer
simulations is performed to trace the trajectories of the flow galaxies back in
time to the epoch of the formation of the Local Group. It is found that the
`initial conditions' of the flow are drastically different from the linear
velocity-distance relation. The simulations enable also to recognize the major
trends of the flow evolution and identify the dynamical role of universal
antigravity produced by cosmic vacuum.


title: RX J1856.5-3754: A strange star with solid quark surface?

abstract:
  Within the realms of the possibility of solid quark matter, we fitted the
500ks Chandra LETG/HRC data for RX J1856.5-3754 with a phenomenological
spectral model, and found that electric conductivity of quark matter on the
stellar surface is about > 1.2 x 10^{18} s^{-1}.


title: Solid Bare Strange Quark Stars

abstract:
  The reason, we need three terms of `strange', `bare', and `solid' before
quark stars, is presented concisely though some fundamental issues are not
certain. Observations favoring these stars are introduced.


title: HD 161796 (IRAS 17436+5003)

abstract:
  Past imaging observations of a post-AGB star, HD 161796, have probed
different parts of its circumstellar shell which correspond to different epochs
of the star's AGB mass loss history. While the overall structure of the shell
can be described by an axisymmetric model consisting of three layers of
characteristic structure, the mass distribution in the shell appears to rotate
its axis of symmetry in a continuous manner. It is thus interesting to observe
the halo region of the shell using from far-IR to sub-mm wavelengths and
increase the ``time resolution'' during this critical epoch of the star's mass
loss history.


title: HST/NICMOS Imaging Polarimetry of PPNs

abstract:
  We present the preliminary results from our HST/NICMOS imaging polarimetry on
optically thin PPNs. The data show the dust distribution in an unprecedented
detail. The structure of these faint PPNs is revealed via polarization
properties of the dust-scattered light without much interference from the
bright central star, proving the unique advantages of the technique over simple
imaging.


title: The Post-Agb Star IRAS 16594-4656

abstract:
  We present the basic properties of the multipolar post-AGB star IRAS
16594-4656, and discuss in particular its near infrared spectrum which shows
shock excited H2 and [Fe II] emission lines.


title: Cross-correlation between the soft X-ray background and SZ Sky

abstract:
  While both X-ray emission and Sunyaev-Zel'dovich (SZ) temperature
fluctuations are generated by the warm-hot gas in dark matter halos, the two
observables have different dependence on the underlying physical properties,
including the gas distribution. A cross-correlation between the soft X-ray
background (SXRB) and the SZ sky may allow an additional probe on the
distribution of warm-hot gas at intermediate angular scales and redshifts
complementing studies involving clustering within SXRB and SZ separately. Using
a halo approach, we investigate this cross-correlation analytically. The two
contributions are correlated mildly with a correlation coefficient of
$\sim0.3$, and this relatively low correlation presents a significant challenge
for its detection. The correlation, at small angular scales, is affected by the
presence of radiative cooling or preheating and provides a probe on the thermal
history of the hot gas in dark halos. While the correlation remains
undetectable with CMB data from the WMAP satellite and X-ray background data
from existing catalogs, upcoming observations with CMB missions such as Planck,
for the SZ side, and an improved X-ray map of the large scale structure, such
as the one planned with DUET mission, may provide a first opportunity for a
reliable detection of this cross-correlation.


title:
The first detection of Far-Infrared emission associated with an extended
  HI disk. The case of NGC 891

abstract:
  Spiral galaxies in the Local Universe are commonly observed to be embedded in
extended disks of neutral hydrogen - the so called ``extended HI disks''. Based
on observations made using the ISOPHOT instrument on board the Infrared Space
Observatory, we report the first detection of cold dust in the extended HI disk
of a spiral galaxy. The detection was achieved through a dedicated deep
Far-Infrared observation of a large field encompassing the entire HI disk of
the edge-on spiral galaxy NGC 891. Our discovery indicates that the extended HI
disk of NGC 891 is not primordial in origin.


title: Observational Properties of Type II Plateau Supernovae

abstract:
  We present spectroscopic and photometric data of a sample of Type II plateau
Supernovae, covering a wide range of properties, from the $^{56}$Ni rich, high
luminosity events (e.g. SN 1992am) to the low-luminosity, $^{56}$Ni poor SNe
(e.g. SN 1997D). We provide an observational framework to analyze correlations
among observational data, physical parameters and progenitors characteristics
of Type II Supernovae.


title: Understanding Type II Supernovae

abstract:
  We present the results of a systematic analysis of a group of Type II plateau
supernovae that span a large range in luminosities, from faint objects like SN
1997D and 1999br to very luminous events like SN 1992am. The physical
properties of the supernovae appear to be related to the plateau luminosity or
the expansion velocity. The simultaneous analysis of the observed light curves,
line velocities and continuum temperatures leads us to robust estimates of the
physical parameters of the ejected envelope. We find strong correlations among
several parameters. The implications of these results regarding the nature of
the progenitor, the central remnant and the Ni yield are also addressed.