title:
Fabry-Perot Absorption-Line Spectroscopy of NGC 7079: Kinematics and Bar
  Pattern Speed

abstract:
  We present Fabry-Perot absorption-line spectroscopy of the SB0 galaxy NGC
7079. This is the first use of Fabry-Perot techniques to measure the
two-dimensional stellar kinematics of an early-type disk galaxy. We scan the
infrared CaII line using the Rutgers Fabry-Perot (RFP), to obtain kinematic
data extending to $I$-band surface brightness $\mu_I \simeq 21$ mag./arcsec^-2,
in a field of radius $\sim 40\arcsec$. The kinematic data, consisting of
line-of-sight velocities and velocity dispersions, are in good agreement with
data obtained along the major axis of the disk with standard slit spectroscopy.
Comparison of the exposure times required for slit and RFP spectroscopy to
reach the same limiting magnitude shows that the RFP is significantly more
efficient for mapping absorption-line galaxy kinematics. We use the velocity
data, together with our own deep broad-band photometry,to measure the bar
pattern speed, $\Omega_p$, of NGC 7079 with the model-independent
Tremaine-Weinberg (TW) method. We find $\Omega_p = 8.4 \pm 0.2$ km/s/arcsec;
this is the best-constrained pattern speed ever measured for a bar using the TW
method. From the rotation curve, corrected for asymmetric drift, we calculate
the co-rotation radius and find that the bar ends just inside this radius. The
two-dimensional character of these data allow us to show that the TW method is
sensitive to errors in the position angle (PA) of the disk. For example, a PA
error of $2\degrees$ can give errors $\sim \pm 25%$ in $\Omega_p$.


title:
Probing the cosmological variation of the fine-structure constant:
  Results based on VLT-UVES sample

abstract:
  Development of fundamental physics relies on the constancy of various
fundamental quantities such as the fine structure constant. Detecting or
constraining the possible time variations of these fundamental physical
quantities is an important step toward a complete understanding of basic
physics. Here we present the results from a detailed many-multiplet analysis
performed using high signal-to-noise ratio, high spectral resolution
observations of 23 Mg II systems detected toward 18 QSOs in the redshift range
0.4<z<2.3 obtained using UVES at the VLT. We validate our procedure and define
the selection criteria that will avoid possible systematics using detail
analysis of simulated data set. We show our Voigt profile fitting code recovers
the variation in \alpha very accurately when we use single component systems
and multiple component systems that are not heavily blended. Spurious
detections are frequently seen when we use heavily blended systems or the
systems with very weak lines. Thus we avoided heavily blended systems and the
systems with Fe II column density < 2x10^12 cm^-2 in the analysis. All steps
involved in the analysis are presented in detail. The weighted mean value of
the variation in \alpha obtained from our analysis over the redshift range
0.4<z<2.3 is {\Delta\alpha/\alpha} = (-0.06+/-0.06)x10^-5. The median redshift
of our sample is 1.55 the 3\sigma upper limit on the time variation of $\alpha$
is -2.5x10^-16 yr^-1< (\Delta\alpha/\alpha\Delta t) <+1.2x10^-16 yr^-1. To our
knowledge this is the strongest constraint from quasar absorption line studies
till date.


title:
Determining the equation of state of dark energy from angular size of
  compact radio sources and X-ray gas mass fraction of galaxy clusters

abstract:
  Using recent measurements of angular size of high-z milliarcsecond compact
radio sources compiled by Gurvits, Kellermann and Frey (1999) and X-ray gas
mass fraction of galaxy clusters published by Allen et al. (2002,2003), we
explore their bounds on the equation of state, omega_x = p_x/rho_x, of the dark
energy, whose existence has been congruously suggested by various cosmological
observations. We relaxe the usual constraint omega_x >= -1, and find that
combining the two databases yields a nontrivial lower bound on omega_x. Under
the assumption of a flat universe, we obtain a bound -2.22 < omega_x < -0.62 at
95.4% confidence level. The 95.4% confidence bound goes to -1 =< omega_x <
-0.60 when the constraint omega_x >= -1 is imposed.


title: Ages and Metallicities of Hickson Compact Group Galaxies

abstract:
  Hickson Compact Groups (HCGs) constitute an interesting extreme in the range
of environments in which galaxies are located, as the space density of galaxies
in these small groups are otherwise only found in the centres of much larger
clusters. The work presented here uses Lick indices to make a comparison of
ages and chemical compositions of galaxies in HCGs with those in other
environments (clusters, loose groups and the field). The metallicity and
relative abundance of `$\alpha$-elements' show strong correlations with galaxy
age and central velocity dispersion, with similar trends found in all
environments. However, we show that the previously reported correlation between
$\alpha$-element abundance ratios and velocity dispersion disappears when a
full account is taken of the the abundance ratio pattern in the calibration
stars. This correlation is thus found to be an artifact of incomplete
calibration to the Lick system.
  Variations are seen in the ranges and average values of age, metallicity and
$\alpha$-element abundance ratios for galaxies in different environments. Age
distributions support the hierarchical formation prediction that field galaxies
are on average younger than their cluster counterparts. However, the ages of
HCG galaxies are shown to be more similar to those of cluster galaxies than
those in the field, contrary to the expectations of current hierarchical
models. A trend for lower velocity dispersion galaxies to be younger was also
seen. This is again inconsistent with hierarchical collapse models, but is
qualitatively consistent with the latest N-body-SPH models based on monolithic
collapse in which star formation continues for many Gyr in low mass halos.


title: Mass Function of Low Mass Dark Halos

abstract:
  The mass function of dark halos in a Lambda-dominated cold dark matter
(LambdaCDM) universe is investigated. 529 output files from five runs of N-body
simulations are analyzed using the friends-of-friends cluster finding
algorithm. All the runs use 512^3 particles in the box size of 35 h^{-1}Mpc to
140 h^{-1}Mpc. Mass of particles for 35 h^{-1} Mpc runs is 2.67 times 10^7
h^{-1} M_{solar}. Because of the high mass resolution of our simulations, the
multiplicity function in the low-mass range, where the mass is well below the
characteristic mass and $\nu = \delta_c / \sigma \lesssim 1.0$, is evaluated in
the present work, and is well fitted by the functional form proposed by Sheth &
Tormen (ST). However, the maximum value of the multiplicity function from our
simulations at $\nu \sim 1$ is smaller, and its low mass tail is shallower when
compared with the ST multiplicity function.


title: A New Giant Stellar Structure in the Outer Halo of M31

abstract:
  The Sloan Digital Sky Survey has revealed an overdensity of luminous red
giant stars ~ 3 degrees (40 projected kpc) to the northeast of M31, which we
have called Andromeda NE. The line-of-sight distance to Andromeda NE is within
approximately 50 kpc of M31; Andromeda NE is not a physically unrelated
projection. Andromeda NE has a g-band absolute magnitude of ~ -11.6 and central
surface brightness of ~ 29 mag/sq.arcsec, making it nearly two orders of
magnitude more diffuse than any known Local Group dwarf galaxy at that
luminosity. Based on its distance and morphology, Andromeda NE is likely
undergoing tidal disruption. Andromeda NE's red giant branch color is unlike
that of M31's present-day outer disk or the stellar stream reported by Ibata et
al. (2001), arguing against a direct link between Andromeda NE and these
structures. However, Andromeda NE has a red giant branch color similar to that
of the G1 clump; it is possible that these structures are both material torn
off of M31's disk in the distant past, or that these are both part of one
ancient stellar stream.


title: XTRA: The fast X-ray timing detector on XEUS

abstract:
  The Rossi X-ray Timing Explorer (RXTE) has demonstrated that the dynamical
variation of the X-ray emission from accreting neutron stars and stellar mass
black holes is a powerful probe of their strong gravitational fields. At the
same time, the X-ray burst oscillations at the neutron star spin frequency have
been used to set important constraints on the mass and radius of neutron stars,
hence on the equation of state of their high density cores. The X-ray Evolving
Universe Spectroscopy mission (XEUS), the potential follow-on mission to
XMM-Newton, will have a mirror aperture more than ten times larger than the
effective area of the RXTE proportional counter array (PCA). Combined with a
small dedicated fast X-ray timing detector in the focal plane (XTRA: XEUS
Timing for Relativistic Astrophysics), this collecting area will provide a leap
in timing sensitivity by more than one order of magnitude over the PCA for
bright sources, and will open a brand new window on faint X-ray sources, owing
to the negligible detector background. The use of advanced Silicon drift
chambers will further improve the energy resolution by a factor of ~6 over the
PCA, so that spectroscopic diagnostics of the strong field region, such as the
relativistically broadened Iron line, will become exploitable. By combining
fast X-ray timing and spectroscopy, XTRA will thus provide the first real
opportunity to test general relativity in the strong gravity field regime and
to constrain with unprecedented accuracy the equation of state of matter at
supranuclear density.


title: Accretion flows around stellar mass black holes and neutron stars

abstract:
  In this review, I summarize the main X-ray/hard X-ray properties of the
accretion flows around black holes and neutron stars based on recent broad-band
spectral and timing observations performed by the BeppoSAX and Rossi X-ray
Timing Explorer satellites. Emphasizing the spectral and timing similarities
observed between black holes and neutron stars, I discuss on the most likely
accretion geometry and emission processes associated with hard and soft
spectral states. For black holes, in the hard state, the accretion geometry is
more likely made of a truncated disk and a hot inner flow, in which thermal
Comptonization takes place. The truncated disk is likely to be the dominant
source of seed photons, and the site for the production of the reflection
component observed. In soft states, the disk now extends closer to the compact
object and is brighter in X-rays. The hard X-ray emission occurs through
Comptonization of disk photons on a thermal/non-thermal electron distribution,
generated in magnetic flares above the accretion disk. For neutron stars,
similar accretion geometry and emission mechanisms may apply but the
unavoidable radiation from the neutron star surface adds yet another component
in the X-ray spectrum. It also acts as an additional source of cooling for the
Comptonizing cloud, leading to softer spectra in neutron stars than in black
holes.


title: The near-infrared view of galaxy evolution

abstract:
  Near-infrared surveys provide one of the best opportunities to investigate
the cosmic evolution of galaxies and their mass assembly. We briefly review the
main results obtained so far with the K20 and other recent near-IR surveys on
the redshift distribution, the evolution of the luminosity function and
luminosity density, the nature of old and dusty EROs, the evolution of the
galaxy stellar mass function, the properties of the galaxies in the ``redshift
desert'' and the nature of luminous starbursts at z~2.


title: Fe XIII coronal line emission in cool M dwarfs

abstract:
  We report on a search for the Fe xiii forbidden coronal line at 3388.1 \AA in
a sample of 15 M-type dwarf stars covering the whole spectral class as well as
different levels of activity. A clear detection was achieved for LHS 2076
during a major flare and for CN Leo, where the line had been discovered before.
For some other stars the situation is not quite clear. For CN Leo we
investigated the timing behaviour of the Fe xiii line and report a high level
of variability on a timescale of hours which we ascribe to microflare heating.


title: New optical spectra and general discussion on the nature of ULX's

abstract:
  We present spectroscopic observations of three Ultra Luminous X-ray sources
(ULX's). Two of them are very close to the active galaxy NGC 720 and the other
is near NGC 1073. The two around NGC 720 turn out to be quasars at z=0.964 and
z= 2.216, the one near NGC 1073 seems to be associated to an HII region at the
redshift of NGC 1073. We concentrate our analysis on the two quasars and
analyze them in conjunction with a set of 20 additional X-ray sources close to
nearby galaxies which also fit the criteria of ULX's and which also have been
identified as quasars of medium to high redshift. This sample shows an
unusually large fraction of rare BL Lac type objects. The high redshifts of
these ULX's and their close proximity to their low redshift, supposedly parent
galaxies is a surprising result in the light of standard models. We describe
the main properties of each of these objects and their parent galaxy, and
briefly discuss possible interpretations.


title: Radio continuum spectra of galaxies in the Virgo cluster region

abstract:
  New radio continuum observations of galaxies in the Virgo cluster region at
4.85, 8.6, and 10.55 GHz are presented. These observations are combined with
existing measurements at 1.4 and 0.325 GHz. The sample includes 81 galaxies
were spectra with more than two frequencies could be derived. Galaxies that
show a radio-FIR excess exhibit central activity (HII, LINER, AGN). The four
Virgo galaxies with the highest absolute radio excess are found within 2
degrees of the center of the cluster. Galaxies showing flat radio spectra also
host active centers. There is no clear trend between the spectral index and the
galaxy's distance to the cluster center.


title: The efficiency of the magnetic acceleration in relativistic jets

abstract:
  Using steady, axisymmetric, ideal magnetohydrodynamics (MHD) we analyze
relativistic outflows by means of examining the momentum equation along the
flow and in the transfield direction. We argue that the asymptotic Lorentz
factor is ~ mu-sigma_M, and the asymptotic value of the Poynting-to-matter
energy flux ratio - the so-called sigma function - is given by sigma/(1+sigma)
\~ sigma_M / mu, where sigma_M is the Michel's magnetization parameter and mu
c^2 the total energy-to-mass flux ratio. We discuss how these values depend on
the conditions near the origin of the flow. By employing self-similar solutions
we verify the above result, and show that a Poynting-dominated flow near the
source reaches equipartition between Poynting and matter energy fluxes, or even
becomes matter-dominated, depending on the value of sigma_M / mu.


title: Cold filaments in galaxy clusters: effects of heat conduction

abstract:
  We determine the critical size l_crit of a filament of cold (T~10^4 K) gas
that is in radiative equilibrium with X-ray emitting gas at temperatures
T_out~10^6 - 10^8 K. Filaments smaller than l_crit will be rapidly evaporated,
while longer ones will induce the condensation of the ambient medium. At fixed
pressure P, l_crit increases as T_out^(11/4), while at fixed T_out it scales as
1/P. It scales as f^(1/2), where f is the factor by which the magnetic field
depresses the thermal conductivity below Spitzer's benchmark value. For
plausible values of f, l_crit is similar to the lengths of observed filaments.
In a cluster such as Perseus, the value of l_crit increases by over an order of
magnitude between the centre and a radius of 100 kpc. If the spectrum of seed
filament lengths l is strongly falling with l, as is natural, then these
results explain why filaments are only seen within a few kiloparsecs of the
centres of clusters, and are not seen in clusters that have no cooling flow. We
calculate the differential emission measure as a function of temperature for
the interface between filaments and ambient gas of various temperatures. We
discuss the implications of our results for the origin of the galaxy luminosity
function.


title: Evidence of a multi resonant system within solar periodic activity

abstract:
  To demonstrate a degree of correlation between periodicity in the solar
activity and a multi-resonant system three examples are considered. Although
only two base frequencies were employed a relatively close correlation was
obtained for periodicity, amplitude's envelope and some well-known longer-term
anomalies, by using a simple mathematical formula.


title:
CMB Anisotropies, Cosmological Parameters and Fundamental Physics:
  Current Status & Perspectives

abstract:
  I describe briefly the Cosmic Microwave Background (hereafter CMB) physics
which explains why high accuracy observations of its spatial structure are a
unique observational tool both for the determination of the global cosmological
parameters and to constrain observationally the physics of the early universe.
I also briefly survey the many experiments which have measured the anisotropies
of the CMB and led to crucial advances in observational Cosmology. The somewhat
frantic series of new results has recently culminated with the outcome of the
WMAP satellite which confirmed earlier results, set new standards of accuracy,
and suggested that the Universe may have reionised earlier than anticipated.
Many more CMB experiments are currently taking data or being planned, with the
Planck satellite on the 2007 Horizon poised to extract all the cosmological
information in the temperature anisotropies, and foray deeply into
polarisation.


title: Spectra of Poynting-flux powered GRB outflows

abstract:
  We investigate the production of the gamma-ray spectrum of a Poynting-flux
dominated GRB ouflow. The very high magnetic field strengths
(super-equipartition) in such a flow lead to very efficient synchrotron
emission. In contrast with internal shocks, dissipation of magnetic energy by
reconnection is gradual and does not produce the spectrum of cooling electrons
associated with shock acceleration.We show that a spectrum with a break in the
BATSE energy range is produced, instead, if the magnetic dissipation heats a
small (\sim 10^{-4}) population of electrons.


title: Shock acceleration and gamma radiation in the intracluster medium

abstract:
  Particle acceleration is expected to take place at shocks that form during
the process of large scale structure formation. Electrons accelerated at such
shocks can upscatter a small fraction of the photons in the cosmic microwave
background up to the gamma ray band. Here we make predictions about the
detectability of the $\gamma$--ray emission from forming clusters of galaxies
with future GeV and TeV gamma ray telescopes. We also estimate the contribution
of these sources to the extragalactic diffuse gamma ray background.


title: The Pulsed Spectra of Two Extraordinary Pulsars

abstract:
  We report on X-ray monitoring of two isolated pulsars within the same RXTE
field of view. PSR J1811-1925 in the young supernova remnant G11.2-0.3 has a
nearly sinusoidal pulse profile with a hard pulsed spectrum (photon index
\~1.2). The pulsar is a highly efficient (~ 1% of spin-down energy) emitter of
2-50 keV pulsed X-rays despite having a fairly typical B ~ 2e12 G magnetic
field. PSR J1809-1943/XTE J1810-197 is a newly discovered slow (P=5.54 s),
apparently isolated X-ray pulsar which increased in flux by a factor of ~100 in
2003 January. Nine months of monitoring observations have shown a decrease in
pulsed flux of ~ 30% without a significant change in its apparently thermal
spectrum (kT ~0.7 keV) or pulse profile. During this time, the spin-down torque
has fluctuated by a factor of ~ 2. Both the torque and the flux have remained
steady for the last 3 months, at levels consistent with a magnetar
interpretation.


title: Linking radio to infrared: a radio source count model

abstract:
  We investigate the populations and evolution of normal and active galaxies by
extending the infrared source count model of Rowan-Robinson (2001) into the
radio. The FIR-radio correlation is used to extend the SEDs to the radio region
and it is assumed that there are two distinct populations of quasar: radio loud
and radio quiet. It is found that the radio luminosity function and source
count data are best fit when the fraction of quasars that are radio loud is
allowed to increase with optical luminosity. This implications for this are
discussed, as are the possible causes for the variation in radio loud fraction.


title:
WIMP diffusion in the solar system including solar depletion and its
  effect on Earth capture rates

abstract:
  Weakly Interacting Massive Particles (WIMPs) can be captured by the Earth,
where they eventually sink to the core, annihilate and produce e.g. neutrinos
that can be searched for with neutrino telescopes. The Earth is believed to
capture WIMPs not dominantly from the Milky Way halo directly, but instead from
a distribution of WIMPs that have diffused around in the solar system due to
gravitational interactions with the planets in the solar system. Recently,
doubts have been raised about the lifetime of these WIMP orbits due to solar
capture. We here investigate this issue by detailed numerical simulations.
  Compared to earlier estimates, we find that the WIMP velocity distribution is
significantly suppressed below about 70 km/s which results in a suppression of
the capture rates mainly for heavier WIMPs (above ~100 GeV). At 1 TeV and above
the reduction is almost a factor of 10.
  We apply these results to the case where the WIMP is a supersymmetric
neutralino and find that, within the Minimal Supersymmetric Standard Model
(MSSM), the annihilation rates, and thus the neutrino fluxes, are reduced even
more than the capture rates. At high masses (above ~1 TeV), the suppression is
almost two orders of magnitude.
  This suppression will make the detection of neutrinos from heavy WIMP
annihilations in the Earth much harder compared to earlier estimates.


title:
Acceleration of particles in pulsar magnetosphere and the X-ray
  radiation

abstract:
  The available data of single X-ray pulsars, their wind nebulae, and the SNRs
which are connected to some of these sources are analysed. It is shown that
electric field intensity of neutron stars tears off charged particles from the
surface of neutron star and triggers the acceleration of particles. The charged
particles are accelerated mainly in the field of magnetodipole radiation wave.
Power and energy spectra of the charged particles depend on the strength of the
magnetodipole radiation. Therefore, the X-ray radiation is strongly dependent
on the rate of rotational energy loss and weakly dependent on the electric
field intensity. Coulomb interaction between the charged particles is the main
factor for the energy loss and the X-ray spectra of the charged particles.


title:
Neutral beam model for the anomalous gamma-ray emission component in GRB
  941017

abstract:
  Gonz\'alez et al. (2003) have reported the discovery of an anomalous
radiation component from ~ 1 -- 200 MeV in GRB 941017. This component varies
independently of and contains > 3 times the energy found in the prompt ~ 50 keV
-- 1 MeV radiation component that is well described by the relativistic
synchrotron-shock model. Acceleration of hadrons to very high energies can give
rise to two additional emission components, one produced inside the GRB blast
wave and one associated with an escaping beam of ultra-high energy (UHE; >
10^{14} eV) neutrons, gamma rays, and neutrinos. The first component extending
to ~ 100 MeV is from a pair-photon cascade induced by photomeson processes with
the internal synchrotron photons coincident with the prompt radiation. The
outflowing UHE neutral beam can undergo further interactions with external
photons from the backscattered photon field to produce a beam of
hyper-relativistic electrons that lose most of their energy during a fraction
of a gyroperiod in the assumed Gauss-strength magnetic fields of the
circumburst medium. The synchrotron radiation of these electrons has a spectrum
with vF_v index equal to +1 that can explain the anomalous component in GRB
941017. This interpretation of the spectrum of GRB 941017 requires a high
baryon load of the accelerated particles in GRB blast waves. It implies that
most of the radiation associated with the anomalous component is released at >
500 MeV, suitable for observations with GLAST, and with a comparable energy
fluence in ~100 TeV neutrinos that could be detected with a km-scale neutrino
telescope like IceCube.


title:
The fundamental plane of black hole activity and the census of the local
  black holes' population

abstract:
  Studying a sample of both strongly and weakly active galactic nuclei with
measured masses and 5 GHz and 2-10 keV core luminosities, together with a few
galactic black holes simultaneously observed in the radio and X-ray bands,
Merloni, Heinz, & Di Matteo (2003) showed that the sources are correlated
through a ``fundamental plane'' relationship in the three-dimensional (log L_R,
log L_X, log M) space. Here I elaborate on how such a relationship can be used
to infer directly mass and accretion rate of any black hole given its radio and
X-ray fluxes, complementing the information obtained from optical/UV surveys.
As an example, I show how the local X-ray and radio luminosity functions,
coupled with the black hole mass function derived from the M-\sigma relation,
provide us with an accretion rate function. It is found that the typical X-ray
Eddington ratio of an active black hole at redshift zero is about 5 \times
10^{-4}.


title: The Nature of X-ray Bright Optically Normal Galaxies

abstract:
  Recent X-ray surveys by {\it Chandra} and {\it XMM-Newton} have revealed a
population of X-ray bright, optically normal galaxies (XBONGs) at moderate
redshifts. We propose that many XBONGs are powered by an inner radiatively
inefficient accretion flow (RIAF) plus an outer radiatively efficient thin
accretion disk. The absence of optical/UV activity in XBONGs is explained by
the truncation of the thin disk near the black hole, while the relatively
strong X-ray emission is explained as inverse Compton emission from the hot
RIAF. As an example, we show that the spectra of two XBONGs can be fit fairly
well with such a model. By comparing these two sources to other accreting black
holes, we argue that XBONGs are intermediate in their characteristics between
distant luminous active galactic nuclei and nearby low-luminosity nuclei.


title: Pulsating sdB Stars: A New Approach to Probing their Interiors

abstract:
  Horizontal branch stars should show significant differential rotation with
depth. Models that assume systematic angular momentum exchange in the
convective envelope and local conservation of angular momentum in the core
produce HB models that preserve a rapidly rotating core. A direct probe of core
rotation is available. The nonradial pulsations of the EC14026 stars frequently
show rich pulsation spectra. Thus their pulsations probe the internal rotation
of these stars, and should show the effects of rapid rotation in their cores.
Using models of sdB stars that include angular momentum evolution, we explore
this possibility and show that some of the sdB pulsators may indeed have
rapidly rotating cores.


title: New Pulsars Coincident With Unidentified Gamma-Ray Sources

abstract:
  We present the results of radio searches for pulsars within unidentified
EGRET source error boxes. Using the Parkes multibeam system, we have surveyed
56 sources at Galactic latitudes |b| > 5 deg which do not appear to be
associated with blazars. This population has been suggested to be distributed
like the local star forming region known as the Gould Belt, the Galactic Halo,
and/or the millisecond pulsars. We have discovered several new pulsars in this
survey, including three new binary systems.


title: Recent Searches for Pulsars in Unidentified EGRET Error Boxes

abstract:
  Pulsars discovered since the end of the EGRET mission coincident with
unidentified high-energy gamma-ray sources are prime targets for AGILE. Both
general surveys and targeted observations have been successful in finding
energetic young pulsars in the plane of the Galaxy. For the latter, hard X-ray
imaging followed by deep radio searches of X-ray sources is a proven route.
High-resolution Chandra X-ray imaging has discovered several asymmetric pulsar
wind nebulae associated with apparently variable gamma-ray sources along the
Galactic plane. The unidentified sources at intermediate Galactic latitudes,
with their much larger error boxes, make new X-ray studies impractical. A radio
search of a number of these sources using the Parkes multibeam system has
resulted in the detection of several new binary pulsar systems. Whether these
are potential gamma-ray emitters has yet to be determined.


title: Multi-Tree Methods for Statistics on Very Large Datasets in Astronomy

abstract:
  Many fundamental statistical methods have become critical tools for
scientific data analysis yet do not scale tractably to modern large datasets.
This paper will describe very recent algorithms based on computational geometry
which have dramatically reduced the computational complexity of 1) kernel
density estimation (which also extends to nonparametric regression,
classification, and clustering), and 2) the n-point correlation function for
arbitrary n. These new multi-tree methods typically yield orders of magnitude
in speedup over the previous state of the art for similar accuracy, making
millions of data points tractable on desktop workstations for the first time.


title: High Energy Gamma-Ray Astronomy

abstract:
  The physics results of high energy gamma-ray astronomy are reported,
emphasizing recent achievements with ground-based detectors. This includes some
of the instrumental developments and latest projects. The fundamental
contribution of the field to the question of Cosmic Ray origin is highlighted.


title:
The Optical Gravitational Lensing Experiment. Real Time Data Analysis
  Systems in the OGLE-III Survey

abstract:
  We describe three real time data analysis systems implemented during the
third phase of the OGLE survey (OGLE-III). The EWS system is designed to detect
on-going microlensing events. The EEWS system monitors the microlensing
phenomena for anomalies from the single mass microlensing. The NOOS system
detects transient objects in the OGLE-III fields (SNe, microlensing events,
variable stars) that normally are below the detection threshold. Information on
objects detected by each of these systems is distributed to the astronomical
community for follow up observations. Also a short description of the OGLE-III
hardware and photometric data pipeline is presented.


title: The polarisation of afterglow emission reveals GRB jet structure

abstract:
  We numerically compute light and polarisation curves of gamma-ray burst
afterglows for various configurations of the jet luminosity structure and for
different dynamical evolutions. We especially consider the standard homogeneous
``top hat'' jet and the ``universal structured jet'' with power-law wings. We
also investigate a possible more physical variation of the ``top hat'' model:
the ``Gaussian jet''. The polarisation curves for the last two jet types are
shown here for the first time together with the computation of X-ray and radio
polarised fluxes. We show that the lightcurves of the total flux from these
configurations are very similar to each other, and therefore only very high
quality data could allow us to pin down the underlying jet structure. We
demonstrate instead that polarisation curves are a powerful means to solve the
jet structure, since the predicted behaviour of polarisation and its position
angle at times around the jet break are very different if not opposite. We
conclude that the afterglow polarisation measurements provide clear footprints
of any outflow energy distribution (unlike the lightcurves of the total flux)
and the joint analysis of the total and polarised flux should reveal GRBs jet
structure.


title:
The All Sky Automated Survey. The Catalog of Variable Stars. II.6h-12h
  Quarter of the Southern Hemisphere

abstract:
  This paper describes the second part of the photometric data from the 9x9 deg
ASAS camera monitoring the whole southern hemisphere in the V-band. Preliminary
list of variable stars based on observations obtained since January 2001 is
presented. Over 2,800,000 stars brighter than V=15 mag on 18,000 frames were
analyzed and 11357 were found to be variable (2685 eclipsing, 907 regularly
pulsating, 521 Mira and 7244 other, mostly SR, IRR and LPV stars). Periodic
light curves have been classified using the automated algorithm, which now
takes into account IRAS infrared fluxes. Basic photometric properties are
presented in the tables and some examples of thumbnail light curves are printed
for reference. All photometric data are available over the INTERNET at
http://www.astrouw.edu.pl/~gp/asas/asas.html or
http://archive.princeton.edu/~asas


title:
The elliptical colour-magnitude relation as a discriminant between the
  monolithic and merger paradigms: the importance of progenitor bias

abstract:
  The colour-magnitude relation (CMR) of cluster ellipticals has been widely
used to constrain their star formation histories (SFHs) and to discriminate
between the monolithic and merger paradigms of elliptical galaxy formation. We
investigate the elliptical CMR predicted in the merger paradigm by using a LCDM
hierarchical merger model. We first highlight sections of the literature which
indicate that the traditional use of fixed apertures to derive colours gives a
distorted view of the CMR due to the presence of colour gradients in galaxies.
Fixed aperture observations make the CMR steeper and tighter than it really is.
We then show that the star formation history (SFH) of cluster ellipticals
predicted by the model is quasi-monolithic, with over 95 percent of the total
stellar mass formed before a redshift of 1. The quasi-monolithic SFH produces a
predicted CMR that agrees well at all redshifts with its observed counterpart
once the fixed aperture effect is removed. More importantly, we present
arguments to show that the elliptical-only CMR can be used to constrain the
SFHs of present-day cluster ellipticals only if we believe a priori in the
monolithic collapse model. It is not a meaningful tool for constraining the SFH
in the merger paradigm, because a progressively larger fraction of the
progenitor set of present-day cluster ellipticals is contained in late-type
star forming systems at higher redshift, which cannot be ignored when deriving
the SFHs. Hence, the elliptical-only CMR is not a useful discriminant between
the two competing theories of elliptical galaxy evolution.


title: X-Ray Timing of the Young Pulsar in 3C 58

abstract:
  PSR J0205+6449 is a young pulsar in the Crab-like pulsar wind nebula 3C 58
which is thought to be a result of the historical supernova SN1181 CE. The
65.7-ms pulsar is the second most energetic of the known Galactic pulsars and
has been shown to be remarkably cool for its age, implying non-standard cooling
processes in the neutron star core. We report on RXTE timing observations taken
during AO7 and supplemented by monthly radio observations of the pulsar made
with the Green Bank Telescope (GBT). The total duration covered with the timing
solutions is 450 days. We measure very high levels of timing noise from the
source and find evidence for a ``giant'' glitch of magnitude Delta nu/nu ~
1x10^-6 that occurred in 2002 October. We have also measured the phase-resolved
spectra of the pulsations and find them to be surprisingly hard, with photon
indices Gamma = 0.84 +0.06/-0.15 for the main pulse and Gamma = 1.0 +0.4/-0.3
for the interpulse assuming an absorbed power-law model.


title: [O III]/[N II] as an Abundance Indicator at High Redshift

abstract:
  Among `empirical' methods of estimating oxygen abundances in extragalactic
HII regions, the use of the ratio of nebular lines of [O III] and [N II], first
introduced by Alloin et al. in 1979, is reappraised with modern calibration
data and shown to have certain advantages over R23 = ([O II] + [O III])/Hbeta
and N2 = [NII] 6583/Halpha, particularly when applied to star-forming galaxies
at high redshifts.


title: Fact: Many SCUBA galaxies harbour AGNs

abstract:
  Deep SCUBA surveys have uncovered a large population of ultra-luminous
galaxies at z>1. These sources are often assumed to be starburst galaxies, but
there is growing evidence that a substantial fraction host an AGN (i.e., an
accreting super-massive black hole). We present here possibly the strongest
evidence for this viewpoint to date: the combination of ultra-deep X-ray
observations (the 2 Ms Chandra Deep Field-North) and deep optical spectroscopic
data. We argue that upward of 38% of bright (f850um>=5mJy) SCUBA galaxies host
an AGN, a fraction of which are obscured QSOs (i.e., L_X>3x10^{44} erg/s).
However, using evidence from a variety of analyses, we argue that in almost all
cases the AGNs are not bolometrically important (i.e., <20%). Thus, star
formation appears to dominate their bolometric output. A substantial fraction
of bright SCUBA galaxies show evidence for binary AGN activity. Since these
systems appear to be interacting and merging at optical/near-IR wavelengths,
their super-massive black holes will eventually coalesce.


title:
Probing the Reionization History Using the Spectra of High-Redshift
  Sources

abstract:
  We quantify and discuss the footprints of neutral hydrogen in the
intergalactic medium (IGM) on the spectra of high-redshift (z ~ 6) sources,
using mock spectra generated from hydrodynamical simulations of the IGM. We
show that it should be possible to extract relevant parameters, including the
mean neutral fraction in the IGM, and the radius of the local cosmological
Stromgren region, from the flux distribution in the observed spectra of distant
sources. We focus on quasars, but a similar analysis is applicable to galaxies
and gamma ray burst (GRB) afterglows. We explicitly include uncertainties in
the spectral shape of the assumed source template near the Lyman alpha line.
Our results suggest that a mean neutral hydrogen fraction, x(HI) of unity can
be statistically distinguished from x(HI)<0.01, by combining the spectra of
tens of bright (M = -27) quasars. Alternatively, the same distinction can be
achieved using the spectra of several hundred sources that are ~100 times
fainter. Furthermore, if the radius of the Stromgren sphere can be
independently constrained to within ~10 percent, this distinction can be
achieved using a single source. The information derived from such spectra will
help in settling the current debate as to what extent the universe was
reionized at redshifts near z=6.


title:
Metal Abundances of KISS Galaxies. II. Nebular Abundances of Twelve
  Low-Luminosity Emission-Line Galaxies

abstract:
  We present follow-up spectra of 39 emission-line galaxies (ELGs) from the
KPNO International Spectroscopic Survey (KISS). Many targets were selected as
potentially low metallicity systems based on their absolute B magnitudes and
the metallicity-luminosity relation. The spectra, obtained with the Lick 3-m
telescope, cover the full optical region from [O II]3726,29 to beyond [S
IIl6717,31 and include measurement of [O IIIl4363 in twelve objects. The
spectra are presented and tables of the strong line ratios are given. For
twelve high signal-to-noise ratio spectra, we determine abundance ratios of
oxygen, nitrogen, neon, sulfur and argon. We find these galaxies to be metal
deficient with three systems approaching O/H of 1/25th solar. We compare the
abundance results from the temperature-based T_e method to the results from the
strong-line p_3 method of Pilyguin (2000).


title:
The KPNO International Spectroscopic Survey. IV. H-alpha-selected Survey
  List 2

abstract:
  The KPNO International Spectroscopic Survey (KISS) is an objective-prism
survey for extragalactic emission-line objects. It combines many of the
features of previous slitless spectroscopic surveys with the advantages of
modern CCD detectors, and is the first purely digital objective-prism survey
for emission-line galaxies. Here we present the second list of emission-line
galaxy candidates selected from our red spectral data, which cover the
wavelength range 6400 to 7200 A. In most cases, the detected emission line is
H-alpha. The current survey list covers a 1.6-degree-wide strip located at
Dec(1950) = 43d 30' and spans the RA range 11h 55m to 16h 15m. The survey strip
runs through the center of the Bootes Void, and has enough depth to adequately
sample the far side of the void. An area of 65.8 sq. deg. is covered. A total
of 1029 candidate emission-line objects have been selected for inclusion in the
survey list (15.6 per sq. deg.). We tabulate accurate coordinates and
photometry for each source, as well as estimates of the redshift and
emission-line flux and equivalent width based on measurements of the digital
objective-prism spectra. The properties of the KISS emission-line galaxies are
examined using the available observational data. Although the current survey
covers only a modest fraction of the total volume of the Bootes Void, we
catalog at least twelve objects that appear to be located within the void. Only
one of these objects has been recognized previously as a void galaxy.


title: Radio Continuum Emission at 1.4 GHz from KISS Emission-Line Galaxies

abstract:
  We have searched the Faint Images of the Radio Sky at Twenty centimeters
(FIRST) and the NRAO VLA Sky Survey (NVSS) 1.4 GHz radio surveys for sources
that are coincident with emission-line galaxy (ELG) candidates from the KPNO
International Spectroscopic Survey (KISS). A total of 207 of the 2157 KISS ELGs
(~10%) in the first two H-alpha-selected survey lists were found to possess
radio detections in FIRST and/or NVSS. Follow-up spectra exist for all of the
radio detections, allowing us to determine the activity type (star-forming vs.
AGN) for the entire sample. We explore the properties of the radio-detected
KISS galaxies in order to gain a better insight into the nature of
radio-emitting galaxies in the local universe (z < 0.1). No dwarf galaxies were
detected, despite the large numbers of low-luminosity galaxies present in KISS,
suggesting that lower mass, lower luminosity objects do not possess strong
galaxian-scale magnetic fields. Due to the selection technique used for KISS,
our radio ELGs represent a quasi-volume-limited sample, which allows us to
develop a clearer picture of the radio galaxy population at low redshift.
Nearly 2/3rds of the KISS radio galaxies are starburst/star-forming galaxies,
which is in stark contrast to the results of flux-limited radio surveys that
are dominated by AGNs and elliptical galaxies (i.e., classic radio galaxies).
While there are many AGNs among the KISS radio galaxies, there are no objects
with large radio powers in our local volume. We derive a radio luminosity
function (RLF) for the KISS ELGs that agrees very well with previous RLFs that
adequately sample the lower-luminosity radio population.


title: An RXTE Archival Search for Coherent X-ray Pulsations in LMXB 4U 1820-30

abstract:
  As part of a large-scale search for coherent pulsations from LMXBs in the
RXTE archive, we have completed a detailed series of searches for coherent
pulsations of 4U 1820-30 -- an ultracompact LMXB with a binary period of 11.4
minutes located in the globular cluster NGC6624. The small binary period leads
to a very high acceleration, so we used phase modulation searches as well as
acceleration searches to give significant sensitivity to millisecond
pulsations. We searched a total of 34 archival RXTE observations, 32 of which
had an on-source integration time longer than 10 ks, and some of which were
made consecutively which allowed us to combine them. While we found no
pulsations, we have been able to place the first stringent (95% confidence)
pulsed fraction limits of < 0.8% for all realistic spin frequencies (i.e. < 1
kHz) and likely companion masses (0.02 Msun < Mc < 0.3 Msun). By contrast all
five LMXBs known to emit coherent pulsations have intrinsic pulsed fractions in
the range 3% to 7% when pulsations are observed.


title:
Modulations in the radio light curve of the Type IIb Supernova 2001ig:
  Evidence for a Wolf-Rayet binary progenitor?

abstract:
  We describe the radio evolution of SN 2001ig in NGC 7424, from 700 days of
multi-frequency monitoring with the Australia Telescope Compact Array (ATCA)
and the Very Large Array (VLA). We find that deviations of the radio light
curves at each frequency from the standard "minishell" model are consistent
with density modulations in the circumstellar medium (CSM), which seem to recur
with a period near 150 days. One possibility is that these are due to enhanced
mass-loss from thermal pulses in an AGB star progenitor. A more likely scenario
however is that the progenitor was a Wolf-Rayet star, whose stellar wind
collided with that from a massive hot companion on an eccentric 100 day orbit,
leading to a regular build-up of CSM material on the required time and spatial
scales. Recent observations of "dusty pinwheels" in Wolf-Rayet binary systems
lend credibility to this model. Since such binary systems are also thought to
provide the necessary conditions for envelope-stripping which would cause the
Wolf-Rayet star to appear as a Type Ib/c supernova event rather than a Type II,
these radio observations of SN 2001ig may provide the key to linking Type Ib/c
SNe to Type IIb events, and even to some types of Gamma-Ray Bursts.


title: The Self Creation challenge to the cosmological 'concordance model'

abstract:
  The theory of Self Creation Cosmology is described and found to be as
concordant as the standard cosmological 'concordance model' with local
experiments and cosmological observations. However it does not require the
speculative hypotheses of inflation, dark matter or dark energy. The theory is
highly predictive and when its only free parameter, H, is fixed empirically,
all other cosmological constraints are then determined and found to be
consistent with present observations. It is highly testable and challenges
General Relativity in the geodetic precession measurement to be made by the
Gravity Probe B satellite. The new theory predicts a N-S geodetic plus Thomas
precession about a direction perpendicular to the plane of the orbit of 4.4096
arcsec/yr, that is, 2/3 of that of General Relativity. The predictions of the
'frame dragging' precession of that experiment are equal in both theories that
is 0.0409 arcsec/yr. Furthermore, there are at least two other experiments that
will distinguish between the two theories, which should be performed at the
earliest opportunity, if the geodetic measurement proves to be consistent with
the theory. These experiments ask the questions, "Do photons fall at the same
rate as particles?" and "Is the Casimir force coupled to curvature?"


title: On position angle errors in the Tremaine-Weinberg method

abstract:
  I show that Tremaine-Weinberg (TW) measurements of bar pattern speeds are
sensitive to errors in the position angle of the disc, PA_disc. I use an
$N$-body experiment to measure these errors; for typical random PA_disc errors,
the resulting scatter in the measured values of the dimensionless bar speed
parameter $R$ (defined as the ratio of the corotation radius to the bar
semi-major axis) is of order the observational. I also consider how the
systematic PA_disc errors produced by disc ellipticities affect TW
measurements. The scatter produced by these errors may be significant,
depending on the ellipticity distribution. Conversely, by using the sample of
TW observations, I find that an upper limit of the typical disc (density)
ellipticity is 0.07 at the 90 per cent confidence level, which is in good
agreement with previous measurements. Taken together, the random and systematic
scatter suggest that the intrinsic distribution of $R$ of gas-poor early-type
barred galaxies may be as narrow as that of the gas-rich later-types.


title: Improved Cosmological Constraints from Gravitational Lens Statistics

abstract:
  We combine the Cosmic Lens All-Sky Survey (CLASS) with new Sloan Digital Sky
Survey (SDSS) data on the local velocity dispersion distribution function of
E/S0 galaxies, $\phi(\sigma)$, to derive lens statistics constraints on
$\Omega_\Lambda$ and $\Omega_m$. Previous studies of this kind relied on a
combination of the E/S0 galaxy luminosity function and the Faber-Jackson
relation to characterize the lens galaxy population. However, ignoring
dispersion in the Faber-Jackson relation leads to a biased estimate of
$\phi(\sigma)$ and therefore biased and overconfident constraints on the
cosmological parameters. The measured velocity dispersion function from a large
sample of E/S0 galaxies provides a more reliable method for probing cosmology
with strong lens statistics. Our new constraints are in good agreement with
recent results from the redshift-magnitude relation of Type Ia supernovae.
Adopting the traditional assumption that the E/S0 velocity function is constant
in comoving units, we find a maximum likelihood estimate of $\Omega_\Lambda =
0.74$--0.78 for a spatially flat unvierse (where the range reflects uncertainty
in the number of E/S0 lenses in the CLASS sample), and a 95% confidence upper
bound of $\Omega_\Lambda<0.86$. If $\phi(\sigma)$ instead evolves in accord
with extended Press-Schechter theory, then the maximum likelihood estimate for
$\Omega_\Lambda$ becomes 0.72--0.78, with the 95% confidence upper bound
$\Omega_\Lambda<0.89$. Even without assuming flatness, lensing provides
independent confirmation of the evidence from Type Ia supernovae for a nonzero
dark energy component in the universe.


title: SIMBA's view of the epsilon Eri disk

abstract:
  We present the first observational confirmation for an extended circumstellar
dust disk around epsilon Eri. The observations were obtained with the bolometer
array SIMBA at the 15 m radio telescope SEST in Chile and measure the dust
continuum at 1.2 mm. The emission, with a total flux of 21.4 mJy and a rms of
2.2 mJy/beam, is resolved to a deconvolved size of 27.4 arcsec which
corresponds to 88 AU. No clear indication for a ring-like disk structure is
seen, possibly also due to the telescope's large beam width of 24 arcsec.
Models of the object's spectral energy distribution from IR to mm-wavelengths
show that the emission can also be explained by a simple disk model. We further
demonstrate the strong influence of noise and propose to be cautious with
interpretations of the ring substructure.


title:
Solving the Cooling Flow Problem of Galaxy Clusters by Dark Matter
  Neutralino Annihilation

abstract:
  Recent X-ray observations revealed that strong cooling flow of intracluster
gas is not present in galaxy clusters, even though predicted theoretically if
there is no additional heating source. I show that relativistic particles
produced by dark matter neutralino annihilation in cluster cores provide a
sufficient heating source to suppress the cooling flow, under reasonable
astrophysical circumstances including adiabatic growth of central density
profile, with appropriate particle physics parameters for dark matter
neutralinos. In contrast to other astrophysical heat sources such as AGNs, this
process is a steady and stable feedback over cosmological time scales after
turned on.


title:
Off-Center Carbon Ignition in Rapidly Rotating, Accreting Carbon-Oxygen
  White Dwarfs

abstract:
  We study the effect of stellar rotation on the carbon ignition in a
carbon-oxygen white dwarf accreting CO-rich matter. Including the effect of the
centrifugal force of rotation, we have calculated evolutionary models up to the
carbon ignition for various accretion rates. The rotation velocity at the
stellar surface is set to be the Keplerian velocity. The angular velocity in
the stellar interior has been determined by taking into account the transport
of angular momentum due to turbulent viscosity. We have found that an
off-center carbon ignition occurs even when the effect of stellar rotation is
included if the accretion rate is sufficiently high; the critical accretion
rate for the off-center ignition is hardly changed by the effect of rotation.
Rotation, however, delays the ignition;i.e., the mass coordinate of the
ignition layer and the total mass at the ignition are larger than those for the
corresponding no-rotating model. The result supports our previous conclusion
that a double-white dwarf merger would not be a progenitor of a SN Ia.


title:
A Unified Model of Short and Long Gamma-Ray Bursts, X-Ray Rich Gamma-Ray
  Bursts, and X-Ray Flashes

abstract:
  Taking into account the recent suggestion that a short gamma-ray burst (GRB)
looks like the first 1 sec of a long GRB, we propose that the jet of a GRB
consists of multiple sub-jets or sub-shells (i.e., an inhomogeneous jet model).
The multiplicity of the sub-jets along a line of sight n_s is an important
parameter. If n_s is large (>> 1) the event looks like a long GRB, while if n_s
is small (~1) the event looks like a short GRB. If our line of sight is
off-axis to any sub-jets, the event looks like an X-ray flash or an X-ray rich
GRB. The log-normal distribution of durations of short and long GRBs are also
suggested in the same model.


title:
Two Dimensional Poynting Flux Dominated Flow onto a Schwarzschild Black
  Hole

abstract:
  We discuss the dynamics of the accretion flow onto a black hole driven by
Poynting flux in a simplified model of a two-dimensional accretion disk. In
this simplified model, the condition of the stationary accretion flow is found
to impose a nontrivial constraint on the magnetic field configuration. The
effect of the magnetic field on the accretion flow is discussed in detail using
the paraboloidal and hyperboloidal type configuration for the poloidal
structure suggested by Blandford in 1976. It is demonstrated explicitly that
the angular velocity of the disk, $\Omega_D$, deviates from the Keplerian
angular velocity. The angular velocity of the rigidly-rotating magnetic
surface, $\Omega_F$, does not have to be the same as the angular velocity of
the disk for the paraboloidal type configuration. But for the hyperboloidal
type configuration, it is found that we can set $\Omega_F = \Omega_D$, which
corresponds to an accretion disk of perfect conductor. We discuss the numerical
solutions of the stream equation for stationary accretion flow in the
Schwarzschild background using a paraboloidal type configuration. The dynamics
of the accretion disk is found to depend strongly on the ratio of the accretion
rate to the magnetic field strength.


title:
The star cluster Collinder 232 in the Carina complex and its relation to
  Trumpler 14/16

abstract:
  In this paper we present and analyze new CCD $UBVRI$ photometry down to $V
\approx$ 21 in the region of the young open cluster Collinder 232, located in
the Carina spiral arm, and discuss its relationship to Trumpler 14 and Trumpler
16, the two most prominent young open clusters located in the core of NGC 3372
(the Carina Nebula). First of all we study the extinction pattern in the
region. We find that the total to selective absorption ratio $R_V$ differs from
cluster to cluster, being $3.48\pm0.11$, $4.16\pm0.07$ and $3.73\pm0.01$ for
Trumpler 16, Trumpler 14 and Collinder 232, respectively. Then we derive
individual reddenings and intrinsic colours and magnitudes using the method
devised by Romaniello et al. (2002). Ages, age spreads and distances are then
estimated by comparing the Colour Magnitude Diagrams and the Hertzsprung-Russel
diagram with post and pre-main sequence tracks and isochrones. We find that
Trumpler 14 and Collinder 232 lie at the same distance from the Sun (about 2.5
kpc), whereas Trumpler 16 lies much further out, at about 4 kpc from the Sun.
As for the age, we find that Trumpler 16 is older than both Trumpler 14 and
Collinder 232. For all the clusters we indicate the existence of a significant
age dispersion, whose precise value is hampered by our inability to properly
distinguish members from non-members. We finally suggest that Collinder 232 is
a physical aggregate and provide estimates of its basic parameters.


title: Doppler tomography of Cataclysmic Variables

abstract:
  The study of cataclysmic variables (CVs), and in particular of the evolution
of their accretion discs throughout their different brightness states, has
benefited largely from the use of indirect imaging techniques. I report on the
latest results obtained from Doppler tomography of CVs concentrating mainly on
results published since the 2000 Astrotomography meeting in Brussels. Emphasis
is given to the spiral structures found in the accretion discs of some CVs, to
the evolution of these structures throughout quiescence and outburst, and to
our search for them in more systems.


title: Monte Carlo simulations of the halo white dwarf population

abstract:
  The interpretation of microlensing results towards the Large Magellanic Cloud
(LMC) still remains controversial. Whereas white dwarfs have been proposed to
explain these results and, hence, to contribute significantly to the mass
budget of our Galaxy, there are as well several constraints on the role played
by white dwarfs. In this paper we analyze self-consistently and simultaneously
four different results, namely, the local halo white dwarf luminosity function,
the microlensing results reported by the MACHO team towards the LMC, the
results of Hubble Deep Field (HDF) and the results of the EROS experiment, for
several initial mass functions and halo ages. We find that the proposed
log-normal initial mass functions do not contribute to solve the problem posed
by the observed microlensing events and, moreover, they overproduce white
dwarfs when compared to the results of the HDF and of the EROS survey. We also
find that the contribution of hydrogen-rich white dwarfs to the dynamical mass
of the halo of the Galaxy cannot be more than $\sim 4%$.


title:
The field surrounding NGC 7603: cosmological or non-cosmological
  redshifts?

abstract:
  We present new observations of the field surrounding the Seyfert galaxy NGC
7603, where four galaxies with different redshifts--NGC 7603 (z=0.029), NGC
7603B (z=0.057) and two fainter emission line galaxies (z=0.245 and
z=0.394)--are apparently connected by a narrow filament, leading to a possible
case of anomalous redshift. The observations comprise broad and narrow band
imaging and intermediate resolution spectroscopy of some of the objects in the
field. The new data confirm the redshift of the two emission-line objects found
within the filament connecting NGC 7603 and NGC 7603B, and settles their type
with better accuracy. Although both objects are point-like in ground based
images, using HST archive images we show that the objects have structure with a
FWHM=0.3-0.4 arcsec. This and the relative strength and width of the main
spectral lines allow us to classify these as HII galaxies with very vigorous
star formation, while the rest of the filament and NGC 7603B lack star
formation. We delineate the halo of NGC 7603 out to 26.2 mag/square arcsec in
the Sloan r band filter and find evidence for strong internal distortions. New
narrow emission line galaxies at z=0.246, 0.117 and 0.401 are also found at
respectively 0.8, 1.5 and 1.7 arcmin to the West of the filament within the
fainter contour of this halo. The probability of three background galaxies of
any type with apparent B-magnitudes up to 16.6, 21.1 and 22.1 (the observed
magnitudes, extinction correction included) being randomly projected on the
filament of the fourth galaxy (NGC 7603) is computed resulting ~ 3 x 10^(-9).


title:
On the internal structure of starless cores. I. Physical conditions and
  the distribution of CO, CS, N2H+, and NH3 in L1498 and L1517B

abstract:
  We have characterized the physical structure and chemical composition of two
close-to-round starless cores in Taurus-Auriga, L1498 and L1517B. Our analysis
is based on high angular resolution observations in at least two transitions of
NH3, N2H+, CS, C34S, C18O, and C17O, together with maps of the 1.2 mm
continuum. For both cores, we derive radial profiles of constant temperature
and constant turbulence, together with density distributions close to those of
non-singular isothermal spheres. Using these physical conditions and a Monte
Carlo radiative transfer model, we derive abundance profiles for all species
and model the strong chemical differentiation of the core interiors. According
to our models, the NH3 abundance increases toward the core centers by a factor
of several while N2H+ has a constant abundance over most of the cores. In
contrast, both C18O and CS (and isotopomers) are strongly depleted in the core
interiors, most likely due to their freeze out onto grains at densities of a
few 10^4 cm^{-3}. Concerning the kinematics of the dense gas, we find (in
addition to constant turbulence) a pattern of internal motions at the level of
0.1 km s^{-1}. These motions seem correlated with asymmetries in the pattern of
molecular depletion, and we interpret them as residuals of core contraction.
Their distribution and size suggest that core formation occurs in a rather
irregular manner and with a time scale of a Myr. A comparison of our derived
core properties with those predicted by supersonic turbulence models of core
formation shows that our Taurus cores are much more quiescent than
representative predictions from these models.


title: Mass-loss rates for hot luminous stars: the influence of line branching

abstract:
  The effect of photon frequency redistribution by line branching on mass-loss
rates for hot luminous stars is investigated. Monte Carlo simulations are
carried out for a range of OB-star models which show that previous mass-loss
calculations which neglect non-resonance line scattering overestimate mass-loss
rates for luminous O stars by ~20 per cent. For luminous B stars the effect is
somewhat larger, typically ~50 per cent. A Wolf-Rayet star model is used to
investigate line branching in the strong wind limit. In this case the effect of
line branching is much greater, giving mass-loss rates that are smaller by a
factor ~3 from computations which neglect branching.


title:
The last Gamma Ray Burst in our Galaxy? On the observed cosmic ray
  excess at particle energy 1 EeV

abstract:
  Here we propose that the excess flux of particle events of energy near 1 EeV
from the direction of the Galactic Center region is due to the production of
cosmic rays by the last few Gamma Ray Bursts in our Galaxy. The basic idea is
that protons get accelerated inside Gamma Ray Bursts, then get ejected as
neutrons, decay and so turn back into protons, meander around the inner Galaxy
for some time, and then interact again, turning back to neutrons to be observed
at our distance from the Galactic Center region, where most star formation is
happening in our Galaxy. We demonstrate that this suggestion leads to a
successful interpretation of the data, within the uncertainties of cosmic ray
transport time scales in the inner Galaxy, and in conjunction with many
arguments in the literature.


title:
BVRIJK light curves and radial velocity curves for selected Magellanic
  Cloud Cepheids

abstract:
  We present high precision and well sampled BVRIJK light curves and radial
velocity curves for a sample of five Cepheids in the SMC. In addition we
present radial velocity curves for three Cepheids in the LMC. The low
metallicity (Fe/H ~ -0.7) SMC stars have been selected for use in a
Baade-Wesselink type analysis to constrain the metallicity effect on the
Cepheid Period-Luminosity relation. The stars have periods of around 15 days so
they are similar to the Cepheids observed by the Extragalactic Distance Scale
Key Project on the Hubble Space Telescope. We show that the stars are
representative of the SMC Cepheid population at that period and thus will
provide a good sample for the proposed analysis. The actual Baade-Wesselink
analysis are presented in a companion paper.


title:
The precession of orbital plane and the significant variabilities of
  binary pulsars

abstract:
  There are two kinds of expressions on the precession of orbital plane of a
binary pulsar system, which are given by Barker $&$ O'Connell (1975) and
Apostolatos et al. (1994), Kidder (1995) respectively. This paper points out
that these two kinds of orbital precession velocities are actually obtained by
the same Lagrangian under different degrees of freedom. Correspondingly the
former expression is not consistent with the conservation of the total angular
momentum vector; whereas the latter one is. Damour $&$ Sch\"afer (1988) and Wex
$&$ Kopeikin (1999) have applied Barker $&$ O'Connell's orbital precession
velocity in pulsar timing measurement. This paper applies Apostolatos et al.
$&$ Kidder's orbital precession velocity in pulsar timing measurement. We
analyze that Damour $&$ Sch\"afer's treatment corresponds to negligible
Spin-Orbit induced precession of periastron. Whereas the effects corresponding
to Wex $&$ Kopeikin and this paper are both significant (however they are not
equivalent). The observational data of two typical binary pulsars, PSR
J2051-0827 and PSR J1713+0747 apparently support significant Spin-Orbit
coupling effect. Further more, the discrepancies between Wex $&$ Kopeikin and
this paper can be tested on specific binary pulsars with orbital plane nearly
edge on. If the orbital period derivative of double-pulsar system PSRs
J0737-3039 A and B, with orbital inclination angle $i=87.7_{-29}^{+17}$deg, is
much larger than that of the gravitational radiation induced one, then the
expression of this paper is supported, otherwise Wex $&$ Kopeikin's expression
is supported.


title: TNG Near-IR Photometry of five Galactic Globular Clusters

abstract:
  We present near--infrared J and K observations of giant stars in five
metal-poor Galactic Globular Clusters (namely M3, M5, M10, M13 and M92)
obtained at the Telescopio Nazionale Galileo (TNG). This database has been used
to determine the main photometric properties of the red giant branch (RGB) from
the (K,J-K) and, once combined with the optical data, in the (K,V-K) Color
Magnitude Diagrams. A set of photometric indices (the RGB colors at fixed
magnitudes) and the major RGB evolutionary features (slope, bump, tip) have
been measured. The results have been compared with the relations obtained by
Ferraro et al. 2000 and with the theoretical expectations, showing a very good
agreement.


title:
The Evolution of the Accretion Disk around 4U 1820-30 During a
  Superburst

abstract:
  Accretion from a disk onto a collapsed, relativistic star -- a neutron star
or black hole -- is the mechanism widely believed to be responsible for the
emission from compact X-ray binaries. Because of the extreme spatial resolution
required, it is not yet possible to directly observe the evolution or dynamics
of the inner parts of the accretion disk where general relativistic effects are
dominant. Here, we use the bright X-ray emission from a superburst on the
surface of the neutron star 4U 1820-30 as a spotlight to illuminate the disk
surface. The X-rays cause iron atoms in the disk to fluoresce, allowing a
determination of the ionization state, covering factor and inner radius of the
disk over the course of the burst. The time-resolved spectral fitting shows
that the inner region of the disk is disrupted by the burst, possibly being
heated into a thicker, more tenuous flow, before recovering its previous form
in ~1000 s. This marks the first instance that the evolution of the inner
regions of an accretion disk has been observed in real-time.


title: Spiral shock detection on eclipse maps: Simulations and Observations

abstract:
  We perform simulations in order to reveal the effect of observational and
physical parameters on the reconstruction of a spiral structure in an accretion
disk, using eclipse mapping techniques. We show that a model spiral structure
is smeared to a ``butterfly''-shape structure because of the azimuthal
smoothing effect of the technique. We isolate the effects of phase resolution,
signal-to-noise ratio and accurate centering of the eclipse at zero phase. We
further explore disk emissivity factors such as dilution of the spiral
structure by the disk light and relative spiral arm difference. We conclude
that the spiral structure can be satisfactorily recovered in accretion disk
eclipse maps with phase resolution |\Delta\phi| < 0.01, S/N>25 and zero phase
uncertainty |\Delta\phi| < 0.005, assuming the two spiral arms have similar
brightness and contribute > 30 % to the total disk light. Under the light of
the performed simulations, we present eclipse maps of the IP Peg accretion disk
reconstructed from eclipse light curves of emission lines and continuum during
the outburst of August 1994, where spiral shocks were detected with the aid of
Doppler tomography (Morales-Rueda et al. 2000). We discuss how the detection of
spirals shocks with eclipse mapping is improved with the use of
velocity-resolved eclipse light curves which do not include any contaminating
low-velocity emission.


title:
Sulfur, Chlorine, and Argon Abundances in Planetary Nebulae. IV:
  Synthesis and the Sulfur Anomaly

abstract:
  We have compiled a large sample of O, Ne, S, Cl, and Ar abundances which have
been determined for 85 galactic planetary nebulae in a consistent and
homogeneous manner using spectra extending from 3600-9600 Angstroms. Sulfur
abundances have been computed using the near IR lines of [S III] 9069,9532
along with [S III] temperatures. We find average values, expressed
logarithmically with a standard deviation, of log(S/O)=-1.91(+/-.24),
log(Cl/O)=-3.52(+/-.16), and log(Ar/O)=-2.29(+/-.18), numbers consistent with
previous studies of both planetary nebulae and H II regions. We also find a
strong correlation between [O III] and [S III] temperatures among planetary
nebulae. In analyzing abundances of Ne, S, Cl, and Ar with respect to O, we
find a tight correlation for Ne-O, and loose correlations for Cl-O and Ar-O.
All three trends appear to be colinear with observed correlations for H II
regions. S and O also show a correlation but there is a definite offset from
the behavior exhibited by H II regions and stars. We suggest that this S
anomaly is most easily explained by the existence of S^+3, whose abundance must
be inferred indirectly when only optical spectra are available, in amounts in
excess of what is predicted by model-derived ionization correction factors.
Finally for the disk PNe, abundances of O, Ne, S, Cl, and Ar all show gradients
when plotted against galactocentric distance. The slopes are statistically
indistinguishable from one another, a result which is consistent with the
notion that the cosmic abundances of these elements evolve in lockstep.


title: Magnetic fields in merging spirals - the Antennae

abstract:
  We present an extensive study of magnetic fields in a system of merging
galaxies. We obtained for NGC4038/39 (the Antennae) radio total intensity and
polarization maps at 8.44, 4.86 and 1.49GHz using the VLA in the C and D
configurations. The radio thermal fraction was found to be about 50% at
10.45GHz, higher than in normal spirals. The mean total magnetic fields in both
galaxies are about two times stronger (20microG) than in normal spirals.
However,the degree of field regularity is rather low, implying tangling of the
regular component in regions with interaction-enhanced star formation. Our data
combined with those in HI, Halpha, X-rays and in far infrared allow us to study
local interrelations between different gas phases and magnetic fields. We
distinguish several radio-emitting regions with different physical properties
and at various evolutionary stages. The whole overlapping region shows a
coherent magnetic field structure, probably tracing the line of collision
between the arms of merging spirals while the total radio emission reveals
hidden star formation nests. The southern part of it is a particularly intense
merger-triggered starburst. Highly tangled magnetic fields reach there
strengths of 30microG, even larger than in both individual galaxies, possibly
due to compression of the original fields pulled out from the parent disks. In
the northeastern ridge, away from star-forming regions, the magnetic field is
highly coherent with a strong regular component of 10microG tracing gas
shearing motions along the tidal tail. Modelling Faraday rotation data show
that we deal with a three-dimensionally curved structure of magnetic fields,
becoming almost parallel to the sky plane in the southeastern part of the
ridge.


title: Extinction due to amorphous carbon grains in red quasars from the SDSS

abstract:
  We construct a quasar extinction curve based on the blue and red composite
quasar spectra of Richards et al. (2003) prepared from the SDSS survey. This
extinction curve does not show any traces of the 2200 A feature characteristic
of the Interstellar Medium, and this indicates that graphite grains are likely
absent close to quasar nuclei. The extinction is best modeled by AC amorphous
carbon grains, assuming a standard distribution of grain sizes (p=3.5) but
slightly larger minimum grain size (a_{min} = 0.016 microns) and lower maximum
grain size (a_{min} = 0.12 microns) than the respective canonical values for
the interstellar medium. The dust composition is thus similar to that of the
dust in AGB stars. Since graphite grains form from amorphous carbon exposed to
strong UV irradiation the results indicate that either the dust forms
surprisingly far from the active nucleus or in a wind that leaves the nucleus
quickly enough to avoid crystallization into graphite.


title:
Dynamical friction in flattened systems: A numerical test of Binney's
  approach

abstract:
  We carry out a set of self-consistent N-body calculations to investigate how
important the velocity anisotropy in non-spherical dark-matter haloes is for
dynamical friction. For this purpose we allow satellite galaxies to orbit
within flattened and live dark-matter haloes (DMHs) with aspect-ratio q_h=0.6
and compare the resulting orbit evolution with a semi-analytic code. This code
solves the equation of motion of satellites orbiting within the same DMH and
implements, according to the dynamical friction model, either Chandrasekhar's
formula, which does not incorporate the velocity anisotropy, or Binney's
description of dynamical friction in anisotropic systems. In the numerical and
the two semi-analytic models the satellites are given different initial orbital
inclinations and orbital eccentricities.
  We find that Binney's approach successfully describes the overall satellite
decay and orbital inclination decrease for the whole set of orbits, with an
averaged discrepancy of less than 4 per cent in orbital radius during the first
3 orbits. If Chandrasekhar's expression is used instead, the discrepancy
increases to 20 per cent and no inclination decrease can be observed. Binney's
treatment therefore appears to provide a significantly improved treatment of
dynamical friction in anisotropic systems.


title: Modal decomposition of astronomical images with application to shapelets

abstract:
  The decomposition of an image into a linear combination of digitised basis
functions is an everyday task in astronomy. A general method is presented for
performing such a decomposition optimally into an arbitrary set of digitised
basis functions, which may be linearly dependent, non-orthogonal and
incomplete. It is shown that such circumstances may result even from the
digitisation of continuous basis functions that are orthogonal and complete. In
particular, digitised shapelet basis functions are investigated and are shown
to suffer from such difficulties. As a result the standard method of performing
shapelet analysis produces unnecessarily inaccurate decompositions. The optimal
method presented here is shown to yield more accurate decompositions in all
cases.


title: Entropy "floor" and effervescent heating of intracluster gas

abstract:
  Recent X-ray observations of clusters of galaxies have shown that the entropy
of the intracluster medium (ICM), even at radii as large as half the virial
radius, is higher than that expected from gravitational processes alone. This
is thought to be the result of nongravitational processes influencing the
physical state of the ICM. In this paper, we investigate whether heating by a
central AGN can explain the distribution of excess entropy as a function of
radius. The AGN is assumed to inject buoyant bubbles into the ICM, which heat
the ambient medium by doing pdV work as they rise and expand. Several authors
have suggested that this "effervescent heating" mechanism could allow the
central regions of clusters to avoid the ``cooling catastrophe''. Here we study
the effect of effervescent heating at large radii. Our calculations show that
such a heating mechanism is able to solve the entropy problem. The only free
parameters of the model are the time-averaged luminosity and the AGN lifetime.
The results are mainly sensitive to the total energy injected into the cluster.
Our model predicts that the total energy injected by AGN should be roughly
proportional to the cluster mass. The expected correlation is consistent with a
linear relation between the mass of the central black hole(s) and the mass of
the cluster, which is reminiscent of the Magorrian relation between the black
hole and bulge mass.


title: Gravitational Lensing by Dark Matter Caustics

abstract:
  There are compelling reasons to believe that the dark matter of the universe
is constituted, in large part, by non-baryonic collisionless particles with
very small primordial velocity dispersion. Such particles are called cold dark
matter (CDM). The leading candidates are axions and weakly interacting massive
particles (WIMPs). The word ``collisionless'' indicates that the particles are
so weakly interacting that they move purely under the influence of gravity.
Galaxies are surrounded by CDM and hence, because of gravity, CDM keeps falling
onto galaxies from all directions. CDM infall produces a discrete number of
flows and caustics in the halos of galaxies. There are two types of caustics in
the halos of galaxies: inner and outer. An outer caustic is a simple fold
catastrophe located on a topological sphere enveloping the galaxy. An inner
caustic is a closed tube whose cross-section is an elliptic umbilic
catastrophe, with three cusps. In space, caustics are the boundaries that
separate regions with differing numbers of flows. One side of a caustic surface
has two more flows than the other. The density of CDM particles becomes very
large as one approaches the caustic from the side with the extra flows. Dark
matter caustics have specific density profiles and therefore precisely
calculable gravitational lensing properties. This dissertation presents a
formalism that simplifies the relevant calculations, and apply it to four
specific cases.


title:
Accretion of stars on to a massive black hole: A realistic diffusion
  model and numerical studies

abstract:
  To be presented is a study of the secular evolution of a spherical stellar
system with a central star-accreting black hole (BH) using the anisotropic
gaseous model. This method solves numerically moment equations of the full
Fokker-Planck equation, with Boltzmann-Vlasov terms on the left- and
collisional terms on the right-hand sides. We study the growth of the central
BH due to star accretion at its tidal radius and the feedback of this process
on to the core collapse as well as the post-collapse evolution of the
surrounding stellar cluster in a self-consistent manner. Diffusion in velocity
space into the loss-cone is approximated by a simple model. The results show
that the self-regulated growth of the BH reaches a certain fraction of the
total mass cluster and agree with other methods. Our approach is much faster
than competing ones (Monte Carlo, $N$--body) and provides detailed informations
about the time and space dependent evolution of all relevant properties of the
system. In this work we present the method and study simple models (equal
stellar masses, no stellar evolution or collisions). Nonetheless, a
generalisation to include such effects is conceptually simple and under way.


title:
Improved discretization of the wavelength derivative term in CMF
  operator splitting numerical radiative transfer

abstract:
  We describe two separate wavelength discretization schemes that can be used
in the numerical solution of the comoving frame radiative transfer equation. We
present an improved second order discretization scheme and show that it leads
to significantly less numerical diffusion than previous scheme. We also show
that due to the nature of the second order term in some extreme cases it can
become numerically unstable. We stabilize the scheme by introducing a mixed
discretization scheme and present the results from several test calculations.


title:
Chandra view of Kes 79: a nearly isothermal SNR with rich spatial
  structure

abstract:
  A 30 ks \chandra ACIS-I observation of Kes 79 reveals rich spatial
structures, including many filaments, three partial shells, a loop and a
``protrusion''. Most of them have corresponding radio features. Regardless of
the different results from two non-equilibrium ionization (NEI) codes,
temperatures of different parts of the remnant are all around 0.7 keV, which is
surprisingly constant for a remnant with such rich structure. If thermal
conduction is responsible for smoothing the temperature gradient, a lower limit
on the thermal conductivity of $\sim$ 1/10 of the Spitzer value can be derived.
Thus, thermal conduction may play an important role in the evolution of at
least some SNRs. No spectral signature of the ejecta is found, which suggests
the ejecta material has been well mixed with the ambient medium. From the
morphology and the spectral properties, we suggest the bright inner shell is a
wind-driven shell (WDS) overtaken by the blast wave (the outer shell) and
estimate the age of the remnant to be $\sim$ 6 kyr for the assumed dynamics.
Projection is also required to explain the complicated morphology of Kes 79.


title:
Integrated Sachs-Wolfe effect in Cross-Correlation: The Observer's
  Manual

abstract:
  The Integrated Sachs-Wolfe (ISW) effect is a direct signature of the presence
of dark energy in the universe, in the absence of spatial curvature. A powerful
method for observing the ISW effect is through cross-correlation of the Cosmic
Microwave Background (CMB) with a tracer of the matter in the low redshift
universe. In this paper, we describe the dependence of the obtained
cross-correlation signal on the geometry and other properties of a survey of
the low redshift universe. We show that an all-sky survey with about 10 million
galaxies, almost uniformly distributed within 0<z<1 should yield a near optimal
ISW detection, at ~ 5\sigma level. In order to achieve this level of
signal-to-noise, the systematic anisotropies in the survey must be below ~ 0.1
%, on the scale of ~ 10 degrees on the sky, while the systematic error in
redshift estimates must be less than 0.05.
  Then, we argue that, while an ISW detection will not be a good way of
constraining the conventional properties of dark energy, it could be a valuable
means of testing alternative theories of gravity on large physical scales.


title: A Complete Sample of Soft X-ray Selected AGN: II. Statistical Analysis

abstract:
  Direct correlations and a Principal Component Analysis (PCA) are presented
for a complete sample of 110 soft X-ray selected AGN of which about half are
Narrow-Line Seyfert 1 galaxies (NLS1s). The direct correlation analyses show
that narrower FWHM(H-beta) correlates with steeper X-ray spectrum, stronger
optical FeII emission, weaker [OIII] emission and stronger short-term X-ray
variability. This direct correlation analysis and the PCA confirm the Boroson &
Green (1992) Eigenvector 1 relationship for AGN: FeII strength anti-correlates
with [OIII] line strength. Eigenvector 1 is well-correlated with the Eddington
luminosity ratio L/L_Edd while Eigenvector 2 shows a very good correlation with
the mass of the central black hole and the mass accretion rate. The Eddington
ratio L/L_Edd correlates with the X-ray spectral index alpha-X and the black
home mass anti-correlates with the X-ray variability chi^2/nu. The Eddington
ration L/L_Edd may be interpreted as the age of an AGN: AGN with steep X-ray
spectra, strong FeII, and weak [OIII] are AGN in an early phase of their
evolution. In this hypothesis NLS1s are young AGN.


title:
Theoretical FeI/II/III Emission-Line Strengths from Active Galactic
  Nuclei with Broad-Line Regions

abstract:
  We present theoretical iron emission line strengths for physical conditions
typical of Active Galactic Nuclei with Broad-Line Regions. The non-local
thermodynamic equilibrium (NLTE) models include a new and extensive treatment
of radiative transfer in the FeIII ion, complementing the FeII emission line
strengths predicted in our earlier works. We also briefly present preliminary
results for the FeI emission from AGN using a reduced atom model. We can
satisfactorily reproduce the empirical UV FeIII emission line template of
Vestergaard & Wilkes (2001) for the prototypical narrow-line Seyfert 1 galaxy I
Zw 1, both in terms of the general FeIII flux distribution and the relative
strength of the FeIII and FeII emission. However, a number of detailed features
are still not matched; the most prominent example is the strongest single FeIII
feature observed in the I Zw 1 spectrum, UV47: it is predicted to be strong
only in models suppressing Fe-H charge exchange reactions. We examine the role
of variations in cloud turbulent velocity and iron abundance and carry out
Monte Carlo simulations to demonstrate the effect of uncertainties in atomic
data on the computed spectra.


title: The Birth of a Super Star Cluster: NGC 5253

abstract:
  We present images of the 7mm free-free emission from the radio "supernebula"
in NGC 5253 made with the Very Large Array and the Pie Town link. The images
reveal structure in the nebula, which has a <~ 1 pc (~50 mas radius) core
requiring the excitation of 1200 O7 stars. The nebula is elongated, with an arc
of emission curving to the northeast and to the south. The total ionizing flux
within the central 1.2" (~20 pc) is 7 x 10^52 s^-1, corresponding to 7000 O7
stars. We propose that the radio source is coincident with a small, very red
near-infrared cluster and apparently linked to a larger, optical source some 10
pc away on the sky. We speculate on the causes of this structure and what it
might tell us about the birth of the embedded young super star cluster.


title: Impact of foregrounds on Cosmic Microwave Background maps

abstract:
  We discuss the possible impact of astrophysical foregrounds on three recent
exciting results of Cosmic Microwave Background (CMB) experiments: the WMAP
measurements of the temperature-polarization (TE) correlation power spectrum,
the detection of CMB polarization fluctuations on degree scales by the DASI
experiment, and the excess power on arcminute scales reported by the CBI and
BIMA groups. A big contribution from the Galactic synchrotron emission to the
TE power spectrum on large angular scales is indeed expected, in the lower
frequency WMAP channels, based on current, albeit very uncertain, models; at
higher frequencies the rapid decrease of the synchrotron signal may be, to some
extent, compensated by polarized dust emission. Recent measurements of
polarization properties of extragalactic radio sources at high radio frequency
indicate that their contamination of the CMB polarization on degree scales at
30 GHz is substantially below the expected CMB E-mode amplitude. Adding the
synchrotron contribution, we estimate that the overall foreground contamination
of the signal detected by DASI may be significant but not dominant. The excess
power on arc-min scales detected by the BIMA experiment may be due to
galactic-scale Sunyaev-Zeldovich effects, if the proto-galactic gas is heated
to its virial temperature and its cooling time is comparable to the Hubble time
at the epoch of galaxy formation. A substantial contamination by radio sources
of the signal reported by the CBI group on scales somewhat larger than BIMA's
cannot be easily ruled out.


title: The (In)Stability of Planetary Systems

abstract:
  We present results of numerical simulations which examine the dynamical
stability of known planetary systems, a star with two or more planets. First we
vary the initial conditions of each system based on observational data. We then
determine regions of phase space which produce stable planetary configurations.
For each system we perform 1000 ~1 million year integrations. We examine
upsilon And, HD83443, GJ876, HD82943, 47UMa, HD168443, and the solar system
(SS). We find that the resonant systems, 2 planets in a first order mean motion
resonance, (HD82943 and GJ876) have very narrow zones of stability. The
interacting systems, not in first order resonance, but able to perturb each
other (upsilon And, 47UMa, and SS) have broad regions of stability. The
separated systems, 2 planets beyond 10:1 resonance, (we only examine HD83443
and HD168443) are fully stable. Furthermore we find that the best fits to the
interacting and resonant systems place them very close to unstable regions. The
boundary in phase space between stability and instability depends strongly on
the eccentricities, and (if applicable) the proximity of the system to perfect
resonance. In addition to million year integrations, we also examined stability
on ~100 million year timescales. For each system we ran ~10 long term
simulations, and find that the Keplerian fits to these systems all contain
configurations which may be regular on this timescale.


title: [OII] as a Star Formation Rate Indicator

abstract:
  We investigate the [OII] emission-line as a star formation rate (SFR)
indicator using integrated spectra of 97 galaxies from the Nearby Field
Galaxies Survey (NFGS). The sample includes all Hubble types and contains SFRs
ranging from 0.01 to 100 Msun/yr. We compare the Kennicutt [OII] and H-alpha
SFR calibrations and show that there are two significant effects which produce
disagreement between SFR[OII] and SFR(H-alpha): reddening and metallicity.
Differences in the ionization state of the ISM do not contribute significantly
to the observed difference between SFR([OII]) and SFR(H-alpha) for the NFGS
galaxies with metallicities log(O/H)12>8.5. The Kennicutt [OII]-SFR relation
assumes a typical reddening for nearby galaxies; in practice, the reddening
differs significantly from sample to sample. We derive a new SFR([OII])
calibration which does not contain a reddening assumption. Our new SFR([OII])
calibration also provides an optional correction for metallicity. Our SFRs
derived from [OII] agree with those derived from H-alpha to within 0.03-0.05
dex. We apply our SFR([OII]) calibration with metallicity correction to two
samples: high-redshift 0.8<z<1.6 galaxies from the NICMOS H-alpha survey, and
0.5<z<1.1 galaxies from the Canada-France Redshift Survey. The SFR([OII]) and
SFR(H-alpha) for these samples agree to within the scatter observed for the
NFGS sample, indicating that our SFR([OII]) relation can be applied to both
local and high-z galaxies. Finally, we apply our SFR([OII]) to estimates of the
cosmic star formation history. After reddening and metallicity corrections, the
star formation rate densities derived from [OII] and H-alpha agree to within
30%.


title: Relativistic O VIII Emission and Ionized Outflow in NGC 4051

abstract:
  We present XMM-Newton RGS observations of the soft X-ray spectrum of NGC
4051, and explore their implications for the inner accretion disk and ionized
outflow in the active galactic nucleus. We fit the soft X-ray excess with a
relativistically broadened O VIII recombination spectrum, including the entire
line series and recombination continuum. This plus an underlying power law
continuum provides a much better fit to the soft X-ray spectrum than a single
temperature or disk blackbody plus power law. The emission line profiles,
computed for a Kerr metric around a maximally rotating black hole, reveal a
sharply peaked disk emissivity law and inner radius smaller than 1.7 R_G. The
spectrum also includes narrow absorption and emission lines from C, N, O, Ne,
and Fe in an ionized outflow. Outflow column densities are relatively low and
do not create significant edges in the spectrum. The small amount of absorption
bolsters confidence in the detection of relativistic emission line features.
The narrow-line emitter has a large (76%) global covering fraction, leading to
strong forbidden lines and filling in of the resonance absorption lines. We
also find broad C VI Ly-alpha and very broad O VII emission from the broad-line
region. The narrow and broad-line regions span large ranges in ionization
parameter, and may arise in a disk outflow. The ionized absorber has a large
ionization range which is inconsistent with pressure equilibrium in a
multiphase medium. The mass outflow rate exceeds the accretion rate by a factor
of one thousand.


title:
Discovery of the high--ionization emission line [Ne V] 3426 in the blue
  compact dwarf galaxy Tol 1214-277

abstract:
  The discovery of the high-ionization [Ne V] 3426A emission line in the
spectrum of the blue compact dwarf (BCD) galaxy Tol 1214-277 is reported. The
detection of this line implies the presence of intense ionizing X-ray emission
with a luminosity in the range 10^39-10^40 erg/s. Such a high X-ray luminosity
cannot be reproduced by models of massive stellar populations. Other
mechanisms, such as fast shocks or accretion of gas in high-mass X-ray binaries
need to be invoked to account for the high intensity of the [Ne V] 3426A
emission line.


title:
The Globular Cluster System of NGC 1399. II. Kinematics of a Large
  Sample of Globular Clusters

abstract:
  We study the kinematics and dynamics of the globular cluster system of NGC
1399, the central galaxy of the Fornax cluster. The observational data consists
of medium resolution spectra, obtained at the Very Large Telescope. Our sample
comprises 468 radial velocities in the magnitude range 20 < m_R < 23. This is
the largest sample of globular cluster velocities around any galaxy obtained so
far. The radial range is 2 arcmin < r < 9 arcmin, corresponding to 11 kpc to 50
kpc of galactocentric distance. There is the possibility that unbound clusters
and/or objects in the foreground contaminate the NGC 1399 cluster sample. Under
strong error selection, practically no objects are found with velocities lower
than 800 km/s or higher than 2000 km/s. Since the extreme velocities influence
the velocity dispersion considerably, uncertainty regarding the exact value of
the dispersion remains. Within the above velocity limits, we derive a projected
velocity dispersion for the total sample of 274+-9 km/s which within the
uncertainties remains constant over the entire radial range. Without any
velocity restriction, it increases to 325 km/s. Blue and red clusters show
different dispersions corresponding to their different surface density
profiles. Spherical models point to a circular velocity of 415+-30$ km/s,
assuming isotropy for the red clusters. This value is constant out to 40 kpc.
The inferred dark halo potential can be well represented by a logarithmic
potential. Also a halo of the NFW type fits well to the observations. Some mass
profiles derived from X-ray analyses do not agree with a constant circular
velocity within our radial range, irrespective of its exact value.


title:
An XMM-Newton observation of the nova-like variable UX UMa: spatially
  and spectrally resolved two-component X-ray emission

abstract:
  In the optical and ultraviolet regions of the electromagnetic spectrum, UX
Ursae Majoris is a deeply eclipsing cataclysmic variable. However, no soft
X-ray eclipse was detected in ROSAT observations. We have obtained a 38 ksec
XMM-Newton observation to further constrain the origin of the X-rays. The
combination of spectral and timing information allows us to identify two
components in the X-ray emission of the system. The soft component, dominant
below photon energies of 2 keV, can be fitted with a multi-temperature plasma
model and is uneclipsed. The hard component, dominant above 3 keV, can be
fitted with a kT ~ 5 keV plasma model and appears to be deeply eclipsed. We
suggest that the most likely source of the hard X-ray emission in UX UMa, and
other systems in high mass transfer states, is the boundary layer.


title: H$_2$ Emission Nebulosity Associated with KH 15D

abstract:
  An H$_2$ emission filament is found in close proximity to the unique object
KH 15D using the adaptive optics system of the Subaru Telescope. The morphology
of the filament, the presence of spectroscopic outflow signatures observed by
Hamilton et al., and the detection of extended H$_2$ emission from KH 15D by
Deming, Charbonneau, & Harrington suggest that this filament arises from
shocked H$_2$ in an outflow. The filament extends about 15" to the north of KH
15D.


title: XMM-Newton Observation of the Cluster of Galaxies Abell 1650

abstract:
  We present the nonuniform distribution of temperature and abundance in the
angular extent of 10'(1.4 Mpc) in A1650 observed by XMM-Newton. Spectral
analysis was carried out in 19 systematically-subdivided regions, and in 15
specified regions referred to the hardness ratio (HR) map. The value of HR,
defined as the ratio of counts in the 1.6-10 keV band to those in the 0.8-1.6
keV, is an indicator to investigate the spatial variation of spectral features.
The temperature and abundance were obtained to be 4-6 keV and 0.2-0.5 solar
value with average values of 5.62+0.05-0.07 keV and 0.36+0.02-0.01 solar value
within a radius of 5', respectively. The redshift was derived to be
8.01+0.02-0.02x10^-2 against an optical value of 8.45x10^-2. It turned out that
cool regions with a temperature of around 4 keV and a scalelength of a few 100
kpc are patchily distributed in the outer envelope. This temperature structure
could be explained by the infalling of groups of galaxies into the cluster main
body. More than 30 point sources were found around A1650 in the FOV of 30'. The
spectrum of the Galactic diffuse emission was obtained in the outskirts of
A1650.