title: Distant X-ray Galaxies: Insights from the Local Population

abstract:
  A full understanding of the origin of the hard X-ray background requires a
complete and accurate census of the distant galaxies that produce it.
Unfortunately, distant X-ray galaxies tend to be very faint at all wavelengths,
which hinders efforts to perform this census. This chapter discusses the
insights that can be obtained through comparison of the distant population to
local X-ray galaxies, whose properties are well characterized. Such comparisons
will ultimately aid investigations into the cosmic evolution of supermassive
black holes and their environments.


title:
Intracluster Planetary Nebulae in the Virgo Cluster III: Luminosity of
  the Intracluster Light and Tests of the Spatial Distribution

abstract:
  Intracluster planetary nebulae are a useful tracer of the evolution of
galaxies and galaxy clusters. We analyze our catalog of 318 intracluster
planetary nebulae candidates found in 0.89 square degrees of the Virgo cluster.
We give additional evidence for the great depth of the Virgo cluster's
intracluster stellar population, which implies that the bulk of the
intracluster stars come from late-type galaxies and dwarfs. We also provide
evidence that the intracluster stars are clustered on the sky on arcminute
scales, in agreement with tidal-stripping scenarios of intracluster star
production. Although significant systematic uncertainties exist, we find that
the average fraction of intracluster starlight in the Virgo is 15.8% +/- 3.0%
(statistical) +/- 5.0% (systematic), and may be higher if the intracluster
stars have a large spatial line-of-sight depth. We find that the intracluster
star density changes little with radius or projected density over the range
surveyed. These results, along with other intracluster star observations, imply
that intracluster star production in Virgo is ongoing and consistent with the
cluster's known dynamical youth.


title: Maser action in methanol transitions

abstract:
  We report the detection with the ATCA of 6.7 GHz methanol emission towards
OMC-1. The source has a size between 40'' and 90'', is located to the
south-east of Ori-KL and may coincide in position with the 25 GHz masers. The
source may be an example of an interesting case recently predicted in theory
where the transitions of traditionally different methanol maser classes show
maser activity simultaneously. In addition, results of recent search for
methanol masers from the 25 and 104.3 GHz transitions are reported.


title:
High-velocity gas toward hot molecular cores: evidence for collimated
  outflows from embedded sources

abstract:
  We present observations made with the Berkeley-Illinois-Maryland Association
millimeter array of the H2S 2(2,0)-2(1,1) and C18O 2-1 transitions toward a
sample of four hot molecular cores associated with ultracompact HII regions:
G9.62+0.19, G10.47+0.03, G29.96-0.02 and G31.41+0.31. The angular resolution
varies from 1.5 to 2.4 arcsec, corresponding to scales of ~0.06 pc at the
distance of these sources. High-velocity wings characteristic of molecular
outflows are detected toward all four sources in the H2S line. In two cases
(G29.96 and G31.41) red- and blueshifted lobes are clearly defined and
spatially separate, indicating that the flows are collimated. We also confirm
the previous detection of the outflow in G9.62F. Although the gas-phase H2S
abundance is not well constrained, assuming a value of 10^-7 yields lower
limits to total outflow masses of ~8 Msun, values which are consistent with the
driving sources being massive protostars. Linear velocity gradients are
detected in both C18O and H2S across G9.62, G29.96 and, to a lesser extent,
G31.41. These gradients are observed to be at a different position angle to the
outflow in G9.62F and G29.96, suggestive of a rotation signature in these two
hot cores. Our observations show that these hot cores contain embedded massive
protostellar objects which are driving bipolar outflows. Furthermore, the lack
of strong centimeter-wave emission toward the outflow centers in G29.96 and
G31.41 indicates that the outflow phase begins prior to the formation of a
detectable ultracompact HII region.


title: CI Cam: A Shell-shocked X-ray Nova

abstract:
  We present radio imaging observations of the 1998 outburst of the peculiar
emission line star CI Cam, taken about 1, 4, 75, 82, 93, 163, and 306 days
after the beginning of the 31.64 March 1998 X-ray flare. The first two epochs
show a resolved but compact radio source which becomes optically thin at
frequencies higher than 5 GHz. The later images show a large (120-350 mas)
oval-shaped or double ring remnant. The radio spectrum combined with the high
brightness temperature indicates that the emission is synchrotron, while the
morphology suggests that this is powered by a decelerating shock moving through
dense circumstellar material produced by a strong stellar wind. The radio
images of CI Cam are equally well fit by an expanding ellipsoid or two
expanding rings. The corresponding expansion speed in the plane of the sky was
about 12,000 km/s over the first few days, slowing by a factor of ~3 by the
time of the last observation almost a year later. The radio emission from all
other X-ray binary transients has either been unresolved, or taken the form of
highly collimated relativistic jets. We suggest that CI Cam represents a rare
case where these jets were smothered early on by the unusually dense
circumstellar medium. In this model CI Cam is the analogue to extragalactic
supernovae formed by the collapsar mechanism, while the more usual X-ray
binaries with relativistic jets are analogous to the jets which escape those
supernovae to form a subset of gamma-ray bursts.


title: Gamma Ray Emission from Merger Shocks in the Coma Cluster of Galaxies

abstract:
  A numerical simulation model of the injection and cooling of nonthermal
particles energized by shocks formed in merging clusters of galaxies is used to
fit radio and X-ray data observed from the Coma cluster of galaxies. The
results are consistent with a primary merger-shock origin for both the diffuse
radio halo emission and the hard X-ray excess measured with {\it Beppo-SAX} and
{\it RXTE}. For equal (1%) efficiency of power injected in nonthermal protons
and electrons, we predict that the Coma cluster of galaxies will be
significantly detected with the space-based observatory {\it GLAST}, and
marginally detectable with the ground-based $\gamma$-ray observatories {\it
VERITAS} and {\it HESS}. Significant TeV detections are possible if the
nonthermal proton intensity is greater due to a larger efficiency of nonthermal
hadron acceleration, or to past merger events. The nonthermal hadronic content
in Coma is also revealed by a weak, hard secondary emission component at $\sim
10$ -- 100 GHz. The spectral softening of the radio emission at large radii
from the Coma cluster core derives in this scenario from the decreasing shock
speed away from cluster center for an on-axis merger event. We discuss
differences between merger and delayed turbulence models.


title: The Power of Axisymmetric Pulsar

abstract:
  Stationary force-free magnetosphere of an axisymmetric pulsar is shown to
have a separatrix inclination angle of 77.3$^\circ$. The electromagnetic field
has an $R^{-1/2}$ singularity inside the separatrix near the light cylinder. A
numerical simulation of the magnetosphere which crudely reproduces these
properties is presented. The numerical results are used to estimate the power
of an axisymmetric pulsar: $L=(1\pm 0.1)\mu^2\Omega^4/c^3$. A need for a better
numerical simulation is pointed out.


title:
Phase Referencing and Narrow-Angle Astrometry in Current and Future
  Interferometers

abstract:
  Atmospheric turbulence is a serious problem for ground-based interferometers.
It places tight limits on both sensitivity and measurement precision. Phase
referencing is a method to overcome these limitations via the use of a bright
reference star. The Palomar Testbed Interferometer was designed to use phase
referencing and so can provide a pair of phase-stabilized starlight beams to a
second (science) beam combiner. We have used this capability for several
interesting studies, including very narrow angle astrometry. For close
(1-arcsecond) pairs of stars we are able to achieve a differential astrometric
precision in the range 20-30 micro-arcseconds.


title:
Dust and Diffuse Interstellar Bands in the z_a = 0.524 Absorption System
  toward AO 0235+164

abstract:
  We present new HST STIS NUV-MAMA and STIS CCD observations of the BL Lac
object AO 0235+164 and the intervening damped Ly alpha (DLA) line at z_a =
0.524. The line profile gives N(H I) = 5 +/- 1 x 10^{21} cm^{-2} and, combined
with the H I 21 cm absorption data leads to a spin temperature of T_s = 220 K
+/- 60 K. Those spectra also show a strong, broad feature at the expected
position of the 2175 Angstrom graphitic dust feature at z_a = 0.524. Assuming a
Galactic type dust extinction curve at z_a = 0.524 gives a dust-to-gas ratio of
0.19 Galactic, but the fit, assuming the underlying, un-reddened spectrum is a
single power-law, is poor in the far-UV. A dust-to-gas ratio of 0.19 Galactic
is similar to the LMC, but the AO 0235+164 spectrum does not fit the LMC
extinction curve, or the SMC extinction curve (which has practically no 2175
Angstrom feature). A possible interpretation includes dust similar to Galactic,
but with less of the small particles that produce the far-UV extinction. The
metallicity of the z_a = 0.524 absorber, estimated from the observed N(H I) and
excess X-ray absorption (beyond Galactic) derived from contemporaneous and
archival ASCA and ROSAT X-ray data, is Z = 0.72 +/- 0.28 Z_sun, implying in
turn the dust-to-metals ratio of 0.27 Galactic. If the dust mass density is the
same in the z_a = 0.524 DLA system as in our Galaxy, only 14% (+/- 6%) of the
metals (by mass) are in dust compared with 51%, 36%, and 46% for the Galaxy,
LMC, and SMC respectively. Such a dusty z_a = 0.524 AO 0235+164 absorption
system is a good example of the kind of DLA system that will be missed due to
selection effects, which in turn can bias the measurement of the co-moving
density of interstellar gas (in units of the closure density), Omega_g, as a
function of z.


title: AGB stars in the Local Group, and beyond

abstract:
  I summarize the current status of surveys for late-type M, and Carbon stars
in the Local Group based on three different approaches that make use of the
characteristics of these stars: spectral characteristics using narrow-band
filters, infrared characteristics, and variability.


title: The Twin--Jet System in NGC 1052: VLBI-Scrutiny of the Obscuring Torus

abstract:
  NGC 1052 offers the possibility to study the obscuring torus around a
supermassive black hole, predicted by the standard model of active galactic
nuclei, over a wide range of wavelengths from the radio to the X-ray regime. We
present a detailed VLBI study of the parsec-scale structure of the ``twin-jet''
system in NGC 1052 in both total and polarized intensity and at multiple
frequencies. We report the detection of linearly polarized emission from the
base of the eastern jet at 5 GHz. While the radio spectrum in this region might
be still consistent with synchrotron self absorption, the highly inverted
spectrum of the western jet base represents a clear sign of pronounced
free-free absorption in a circumnuclear torus. We observe an abrupt change of
the brightness temperature gradient at a distance of $\sim 0.2$ pc to 0.3 pc
from the central engine. This might provide an observational signature of the
edge of the central torus, where the transition from an external
pressure-dominated jet regime to a more or less freely expanding jet takes
place. We determine the absorbing column density towards the western jet core
to be $\sim 2.2 \times 10^{22}$ cm$^{-2}$ in good agreement with the values
derived from various X-ray observations. This suggests that the nuclear X-ray
emission and the jet emission imaged by VLBI originate on the same scales.


title:
The Chandra view of NGC1800 and the X-ray scaling properties of dwarf
  starbursts

abstract:
  The superb spatial resolution of Chandra is utilized to study the X-ray
morphology of the dwarf starburst galaxy NGC1800 embedded in a small group of
galaxies. Diffuse galactic emission is detected, extending several kpc above
the galactic plane, with an overall morphology similar to the galactic winds
seen in nearby X-ray bright starburst galaxies. This makes NGC1800 the most
distant dwarf starburst with a clear detection of diffuse X-ray emission. The
diffuse X-ray luminosity of 1.3+/-0.3 *10^38 erg/s accounts for at least 60 per
cent of the total soft X-ray output of the galaxy. A hot gas temperature of
kT=0.25 keV and metallicity Z~0.05Z_Sun are derived, the latter in consistency
with results from optical spectroscopy of the interstellar medium. Our failure
to detect any hot gas associated with the embedding galaxy group translates
into an upper limit to the group X-ray luminosity of L_X<10^41 erg/s. There is
no convincing evidence that the outflowing wind of NGC1800 is currently
interacting with any intragroup gas, and mechanical considerations indicate
that the wind can escape the galaxy and its surrounding HI halo, eventually
delivering energy and metals to the intragroup gas. Properties of NGC1800 are
compared to those of other dwarf starburst galaxies, and a first detailed
discussion of the X-ray scaling properties of this population of objects is
given, set against the equivalent results obtained for normal starburst
galaxies. Results indicate that dwarf starbursts to a large degree behave as
down-scaled versions of normal starburst galaxies.


title:
Are Ultra-Luminous X-ray Sources Intermediate Mass Black Holes Accreting
  from Molecular Clouds?

abstract:
  The origin and nature of Ultra-Luminous X-ray sources (ULXs) is a contentious
and controversial topic. There are ongoing debates about the masses of the
objects responsible, their sources of mass for accretion, and their relation to
stellar populations in galaxies. A new picture of these objects is proposed in
which they are intermediate-mass black holes confined to the disks of their
host galaxies and accreting from the interstellar medium. They are then
preferentially found in or near molecular clouds. This model correctly predicts
the shape of the observed luminosity function and requires only a very small
fraction of the baryonic mass of a galaxy to be in the form of
intermediate-mass black holes. Because the X-rays they produce strongly heat
nearby interstellar gas and because they move relatively rapidly in and out of
dense regions, ULXs are predicted to have brief episodes of high luminosity,
perhaps of order 10^5 yr in duration, but they may recur many times.


title: Coded mask imaging of extended sources with Gaussian random fields

abstract:
  A novel method for generating coded mask patterns based on Gaussian random
fields (GRF) is proposed. In contrast to traditional algorithms based on cyclic
difference sets, it is possible to construct mask patterns that encode a
predefined point spread function (PSF). The viability of this approach and the
reproducibility of the PSFs is examined, together with studies on the mean
transparency, pixel-to-pixel variance and PSF deterioration due to partial
shadowing. Sensitivity considerations suggest the construction of thresholded
realisations of Gaussian random fields (TGRF) which were subjected to the same
analyses. Special emphasis is given to ray-tracing simulations of the pattern's
performance under finite photon statistics in the observation of point sources
as well as of extended sources in comparison to random masks and the pattern
employed in the wide field imager onboard BeppoSAX. A key result is that in
contrast to traditional mask generation schemes, coded masks based on GRFs are
able to identify extended sources at accessible photon statistics. Apart from
simulating on-axis observations with varying levels of signal and background
photon counts, partial shadowing of the mask pattern in the case of off-axis
observations and the corresponding field-of-view is assessed.


title: Why are X-ray sources in the M31 Bulge so close to Planetary Nebulae?

abstract:
  We compare a deep (37 ks) Chandra ACIS-S image of the M31 bulge to deep [O
III] Local Group Survey data of the same region. Through precision image
alignment using globular cluster X-ray sources, we are able to improve
constraints on possible optical/X-ray associations suggested by previous
surveys. Our image registration allows us to rule out several emission-line
objects, previously suggested to be the optical counterparts of X-ray sources,
as true counterparts. At the same time, we find six X-ray sources peculiarly
close to strong [O III] emission-line sources, classified as planetary nebulae
(PNe) by previous optical surveys. Our study shows that, while the X-rays are
not coming from the same gas as the optical line emission, the chances of these
six X-ray sources lying so close to cataloged PNe is only ~1%, suggesting that
there is some connection between these [O III] emitters (possibly PNe) and the
X-ray sources. We discuss the possibility that these nebulae are misidentified
supernova remnants, and we rule out the possibility that the X-ray sources are
ejected X-ray binaries. There is a possibility that some cases involve a PN and
an LMXB that occupy the same undetected star cluster. Beyond this unconfirmed
possibility, and the statistically unlikely one that the associations are
spatial coincidences, we are unable to explain these [O III]/X-ray
associations.


title: Dark matter to dark energy transition in k-essence cosmologies

abstract:
  We implement the transition from dark matter to dark energy in k-essence
cosmologies for a very large set of kinetic functions $F$, in a way alternative
to recent proposals which use generalized Chaplygin gas and transient models.
Here we require that the pressure admits a power-law expansion around some
value of the kinetic energy where the pressure vanishes. In addition, for
suitable values of the parameters of the model, the speed of sound of the dark
matter will be low. We first present the discussion in fairly general terms,
and later consider for illustration two examples.


title: Star Formation in Close Pairs Selected from the Sloan Digital Sky Survey

abstract:
  The effect of galaxy interactions on star formation has been investigated
using Data Release 1 of the Sloan Digital Sky Survey (SDSS). Both the imaging
and spectroscopy data products have been used to construct a catalogue of
nearest companions to a volume limited (0.03 < z < 0.1) sample of galaxies
drawn from the main galaxy sample of SDSS. Of the 13973 galaxies in the volume
limited sample, we have identified 12492 systems with companions at projected
separations less than 300 kpc. Star-formation rates for the volume-limited
sample have been calculated from extinction and aperture corrected H-alpha
luminosities and, where available, IRAS data. Specific star formation rates
were calculated by estimating galaxy masses from z-band luminosities, and
r-band concentration indices were used as an indicator of morphological class.
The mean specific star-formation rate is found to be strongly enhanced for
projected separations of less than 30 kpc. For late-type galaxies the
correlation extends out to projected separations of 300 kpc and is most
pronounced in actively star-forming systems. The specific star-formation rate
is observed to decrease with increasing recessional velocity difference, but
the magnitude of this effect is small compared to that associated with the
projected separation. We also observe a tight relationship between the
concentration index and pair separation; the mean concentration index is
largest for pairs with separations of approximately 75 kpc and declines rapidly
for separations smaller than this. This is interpreted as being due to the
presence of tidally-triggered nuclear starbursts in close pairs. Further, we
find no dependence of star formation enhancement on the morphological type or
mass of the companion galaxy


title: The Planetary Nebula Luminosity Function

abstract:
  The [O III] 5007 planetary nebula luminosity function (PNLF) occupies an
important place on the extragalactic distance ladder: it is the only standard
candle that can be applied to all the large galaxies of the Local Supercluster.
We review the method's precision, and use it to show that the distance scale
defined by Cepheids and the Surface Brightness Fluctuation method is likely too
large by ~ 7%. We also discuss some of the physics underlying the phenomenon,
and present clues as why the technique is so resilient.


title:
An Unveiling Event in the Type 2 AGN NGC4388: A Challenge for a Parsec
  Scale Absorber

abstract:
  We present two Rossi Xray Timing Explorer (RXTE) PCA observations of the
type~2 Seyfert galaxy NGC 4388 caught in an unusual low X-ray absorption state.
The observations were triggered by a detection in the 1.5-3 keV band of the
RXTE All-Sky Monitor. NGC 4388 was found at a somewhat high continuum level
(f(2-10 keV)=8x10(-11)erg cm(-2) s(-1)) and with a column density
(N_H~3x10(22)cm(-2)), a factor ~10 lower than normal. The second PCA
observation, four hours later, gave N_H<2x10(21)cm(-2) indicating, at the 3.1
sigma level, variability so rapid puts the absorber on a few 100 Schwartzschild
radii scale, similar to the Broad Emission Line Region, or smaller. This small
scale creates difficulties for the parsec-scale obscuring torus paradigm of
Unified Schemes for type 1 and type 2 AGNs.


title: Parameters of PNe: constant density versus density distribution

abstract:
  We derive the stellar and circumstellar parameters of the Galactic compact
planetary nebula Hen 2-90 with two models: the classical constant density
nebula model where the emission (especially of the forbiden lines) is formed in
a sphere or shell of constant density, and a model where the emission is formed
in a shell with a $r^{-2}$ density distribution. Depending on the density
$N_{\rm e,0}$ in the second model, the resulting range of valid values can
deviate from the classical model results. This seems to be especially true for
elemental abundances as is shown exemplary for S$^{+}$. We find that the
abundance of S$^{+}$ is larger for the models with density distribution than
for a constant density. A careful analysis of data with an appropriate input
model is advisable when determining stellar and circumstellar parameters of
planetary nebulae not only in our Galaxy.


title:
Evidence for X-ray Obscuration in Type II Quasar Candidates from the
  Sloan Digital Sky Survey

abstract:
  Recently, Zakamska et al. (2003) selected 291 high-ionization narrow
emission-line AGN in the redshift range 0.3-0.83 from the Sloan Digital Sky
Survey spectroscopic data. The sample includes both Seyfert II galaxies and
their higher luminosity "cousins", Type II quasar candidates. Here we present
the results on the X-ray properties of 17 of these objects for which archival
X-ray data (ROSAT and XMM-Newton) are available. Three sources have been
significantly (>6 sigma) detected, one being the most radio-loud source of the
sample; its X-ray emission, possibly enhanced by jet emission, is consistent
with the absence of absorption. Another source has a ~6 sigma detection in the
ROSAT All-Sky Survey, possibly complex radio structure, and no evidence for
strong X-ray absorption. For the third X-ray detection, the XMM-Newton spectrum
indicates a column density of NH=1.26+0.75/-0.51x10^22 cm^-2; this result,
coupled with the 2-10 keV luminosity of ~4x10^44 cgs, makes this source a
genuine Type II quasar. Using the O[III]5007 line luminosities, we estimated
the intrinsic X-ray power of the AGN and found that >47% of the observed sample
shows indications of X-ray absorption, with column densities >10^22 cm^-2. This
provides further evidence that a considerable fraction are obscured quasars.
Support to our conclusions also comes from the recent analysis of RASS data
performed by Zakamska et al. (2004), who found five additional lower
significance (~2.1-3.6 sigma) X-ray matches.


title:
Constraints on the Primordial Power Spectrum from High Resolution
  Lyman-alpha Forest Spectra and WMAP

abstract:
  The combined analysis of the cosmic microwave background on large scales and
Lyman-alpha forest on small scales provides a sufficiently long lever arm to
obtain strong constraints on the slope and curvature of the power spectrum of
primordial density fluctuations. We present results from the combination of the
first year WMAP data and the dark matter power spectrum inferred by Viel et al.
(2004) for two different sets of high resolution and high signal-to-noise
quasar absorption spectra: the Croft et al. (2002) sample with a median
redshift z=2.72 and the LUQAS sample (Kim et al. 2004) with a median redshift
z=2.125. The best fit value for the {\it rms} fluctuation amplitude of matter
fluctuations is sigma_8 =0.94 +- 0.08 and n=0.99 +- 0.03, if we do not include
running of the spectral index. The best fit model with a running spectral index
has parameters n=0.959 +- 0.036 and n_run=-0.033 +- 0.025. The data is thus
consistent with a scale-free primordial power spectrum with no running of the
spectral index. We further include tensor modes and constrain the slow-roll
parameters of inflation.


title: Accelerating Universe with a dynamic cosmological term

abstract:
  Keeping in mind the current picture of an accelerating and flat Universe,
some specific dynamical models of the cosmological term $\Lambda$ have been
selected for investigating the nature of dark energy. Connecting the free
parameters of the models with the cosmic matter and vacuum energy density
parameters, it is shown that the models are equivalent. Using the selected
models, the present values of some of the physical parameters have been
estimated, and a glimpse at the past decelerating universe has also been
presented. It is observed that most of these cosmological parameters nicely
agree with the values suggested by the Type Ia Supernovae and other
experimental data.


title:
Spectral Modelling of Star-Forming Regions in the Ultraviolet: Stellar
  Metallicity Diagnostics for High Redshift Galaxies

abstract:
  The chemical composition of high redshift galaxies is an important property
which gives clues to their past history and future evolution and yet is
difficult to measure with current techniques. In this paper we investigate new
metallicity indicators, based upon the strengths of stellar photospheric
features at rest-frame ultraviolet wavelengths. By combining the evolutionary
spectral synthesis code Starburst99 with the output from the non-LTE model
atmosphere code WM-basic, we have developed a code that can model the
integrated ultraviolet stellar spectra of star-forming regions at metallicities
between 1/20 and twice solar. We use our models to explore a number of spectral
regions that are sensitive to metallicity and clean of other spectral features.
The most promising metallicity indicator is an absorption feature between 1935
A and 2020 A, which arises from the blending of numerous Fe III transitions. We
compare our model spectra to observations of two well studied high redshift
star-forming galaxies, MS1512-cB58 (a Lyman break galaxy at z = 2.7276), and
Q1307-BM1163 (a UV-bright galaxy at z = 1.411). The profiles of the
photospheric absorption features observed in these galaxies are well reproduced
by the models. In addition, the metallicities inferred from their equivalent
widths are in good agreement with previous determinations based on interstellar
absorption and nebular emission lines. Our new technique appears to be a
promising alternative, or complement, to established methods which have only a
limited applicability at high redshifts.


title:
Supermassive Black Holes in Active Galactic Nuclei. II. Calibration of
  the M-sigma Relationship for AGNs

abstract:
  We calibrate reverberation-based black hole masses in active galactic nuclei
(AGNs) by using the correlation between black hole mass, M, and bulge/spheroid
stellar velocity dispersion, sigma. We use new measurements of sigma for 6 AGNs
and published velocity dispersions for 10 others, in conjunction with improved
reverberation mapping results, to determine the scaling factor required to
bring reverberation-based black hole masses into agreement with the quiescent
galaxy M-sigma relationship. The scatter in the AGN black hole masses is found
to be less than a factor of 3. The current observational uncertainties preclude
use of the scaling factor to discriminate between broad-line region models.


title:
Confronting LCDM with Gravitational Lensing Constraints on Small Scale
  Structure

abstract:
  This paper primarily addresses the question of whether recent lensing
observations probing the small scale structure in the universe are consistent
with the LCDM model. A conservative approach is taken where only the most
difficult to explain cases of image flux anomalies in strong lenses are
considered. Numerical simulations are performed to compare predictions for the
LCDM small scale mass function with observed flux ratios. It is found by
simulating several represent cases that all the cusp caustic lens anomalies and
the disagreements between monochromatic flux ratios and simple lens models
might be explained without any substructure in the primary lenses' dark matter
halos. Intergalactic LCDM halos are enough to naturally explain these cases.
However, thus far, spectroscopic gravitational lensing observations require
more small mass halos (~ 10^6 Msun) than is expected in the LCDM model.


title:
Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei.
  II. A Homogeneous Analysis of a Large Reverberation-Mapping Database

abstract:
  We present improved black hole masses for 35 active galactic nuclei (AGNs)
based on a complete and consistent reanalysis of broad emission-line
reverberation-mapping data. From objects with multiple line measurements, we
find that the highest precision measure of the virial product is obtained by
using the cross-correlation function centroid (as opposed to the
cross-correlation function peak) for the time delay and the line dispersion (as
opposed to full width half maximum) for the line width and by measuring the
line width in the variable part of the spectrum. Accurate line-width
measurement depends critically on avoiding contaminating features, in
particular the narrow components of the emission lines. We find that the
precision (or random component of the error) of reverberation-based black hole
mass measurements is typically around 30%, comparable to the precision attained
in measurement of black hole masses in quiescent galaxies by gas or stellar
dynamical methods. Based on results presented in a companion paper by Onken et
al., we provide a zero-point calibration for the reverberation-based black hole
mass scale by using the relationship between black hole mass and host-galaxy
bulge velocity dispersion. The scatter around this relationship implies that
the typical systematic uncertainties in reverberation-based black hole masses
are smaller than a factor of three. We present a preliminary version of a
mass-luminosity relationship that is much better defined than any previous
attempt. Scatter about the mass-luminosity relationship for these AGNs appears
to be real and could be correlated with either Eddington ratio or object
inclination.


title: Correlated isocurvature perturbations from mixed inflaton-curvaton decay

abstract:
  We study cosmological perturbations in the case that present-day matter
consists of a mixture of inflaton and curvaton decay products. We calculate how
the curvaton perturbations are transferred to its decay products in the general
case when it does not behave like dust. Taking into account that the decay
products of the inflaton can also have perturbations results in an interesting
mixture of correlated adiabatic and isocurvature perturbations. In particular,
negative correlation can improve the fit to the CMB data by lowering the
angular power in the Sachs-Wolfe plateau without changing the peak structure.
We do an 11-parameter fit to the WMAP data. We find that the best-fit is not
the 'concordance model', and that well-fitting models do not cluster around the
best-fit, so that cosmological parameters cannot be reliably estimated. We also
find that in our model the mean quadrupole (l=2) power is l(l+1) C_l/2pi = 1081
muK^2, much lower than in the pure adiabatic LCDM model, which gives 1262
muK^2.


title:
Chemical Composition of Planetary Nebulae: The Galaxy and the Magellanic
  Clouds

abstract:
  An analysis is made of the abundances of planetary nebulae (PN) in the Galaxy
(MW), the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC).
The data has been gathered by the IAG/USP group in a homogeneous procedure,
involving observational techniques, data acquisition and reduction. Emphasis is
placed on distance-independent correlations, which are particularly important
for PN in the galactic disk. It is shown that (i) our abundances are comparable
to the accurate abundances of nebulae with ISO data, (ii) most abundance
correlations hold for all three systems, taking into account the metallicity
differences between the Galaxy and the Magellanic Clouds, and (iii) there is a
good general agreement of our data with the predictions of recent theoretical
models for PN progenitors.


title: Variability-selected QSO candidates in OGLE-II Galactic Bulge fields

abstract:
  We present 97 QSO candidates in 48 Galactic Bulge fields of the Optical
Gravitational Lensing Experiment II (OGLE-II) covering about 11 square degrees,
which are selected via their variability. We extend light curves of variable
objects which were detected in 3-year baseline in the OGLE-II variable star
catalog to 4th year. We search for objects which are faint (16<I_0<18.5) and
slowly variable during 4 years in this catalog by using the variogram/structure
function. Finding the QSOs in such stellar-crowded and high extinction fields
is challenging, but should be useful for the astrometric reference frame.
Spectroscopic follow-up observations are required to confirm these QSO
candidates. Follow-up observations are being prepared for four of these fields
(BUL_SC1, 2, 32 and 45). Follow-up observations for other fields are strongly
encouraged. The complete list and light curves of all 97 candidates are
available in electronic format at
http://www.astro.princeton.edu/~sumi/QSO-OGLEII/.


title: Development of super broadband interferometer in FIR

abstract:
  We are developing the super broad band interferometer by applying the Fourier
Transform Spectrometer(FTS) to aperture synthesis system in mm and sub-mm
bands. We have constructed a compact system based on the Martin and Puplett
type Fourier Transform spectrometer (MP-FT). We call this equipment
Multi-Fourier Transform interferometer (MuFT). The band width of the system can
be extended as large as one wants contrary to the severely limited band width
of the usual interferometer due to the speed of the AD converter. The direct
detectors, e.g. bolometer, SIS video detector, can be used as the focal plane
detectors. This type of detectors have a great advantage in FIR band since they
are free from the quantum limit of the noise which limits the sensitivity of
the heterodyne detectors used in the usual interferometers. Further, the direct
detectors are able to make a large format array contrary to the heterodyne
detectors for which construction of a large format array is practically
difficult. These three characteristics make one be possible to develop high
sensitive super broad band FIR interferometer with wide field of view. In the
laboratory experiments, we have succeeded in measuring the spectroscopically
resolved 2D image of the source in 150GHz-900GHz band. The future application
of this technique to the observations from the space could open new interesting
possibilities in FIR astronomy.


title: Constraints on isocurvature models from the WMAP first-year data

abstract:
  We investigate the constraints imposed by the first-year WMAP CMB data
extended to higher multipole by data from ACBAR, BOOMERANG, CBI and the VSA and
by the LSS data from the 2dF galaxy redshift survey on the possible amplitude
of primordial isocurvature modes. A flat universe with CDM and Lambda is
assumed, and the baryon, CDM (CI), and neutrino density (NID) and velocity
(NIV) isocurvature modes are considered. Constraints on the allowed
isocurvature contributions are established from the data for various
combinations of the adiabatic mode and one, two, and three isocurvature modes,
with intermode cross-correlations allowed. Since baryon and CDM isocurvature
are observationally virtually indistinguishable, these modes are not considered
separately. We find that when just a single isocurvature mode is added, the
present data allows an isocurvature fraction as large as 13+-6, 7+-4, and 13+-7
percent for adiabatic plus the CI, NID, and NIV modes, respectively. When two
isocurvature modes plus the adiabatic mode and cross-correlations are allowed,
these percentages rise to 47+-16, 34+-12, and 44+-12 for the combinations
CI+NID, CI+NIV, and NID+NIV, respectively. Finally, when all three isocurvature
modes and cross-correlations are allowed, the admissible isocurvature fraction
rises to 57+-9 per cent. The sensitivity of the results to the choice of prior
probability distribution is examined.


title:
Lithium evolution in intermediate age and old open clusters: NGC 752
  revisited

abstract:
  We present new high resolution spectroscopic observations of the intermediate
age (~2 Gyr) open cluster NGC 752. We investigate the Li vs. Teff distribution
and we obtain a new accurate determination of the cluster metallicity. We
compare the results for NGC 752 with other intermediate age and old clusters
spanning the age range from the Hyades (~0.6 Gyr) to NGC 188 (~6-8 Gyr). We
find that NGC 752 has a solar iron content ([Fe/H]=+0.01+/-0.04), at variance
with early reports of sub-solar metallicity. We find that NGC 752 is only
slightly more Li depleted than the younger Hyades and has a Li pattern almost
identical to that observed in the ~2 Gyr old IC 4651 and NGC 3680. As for the
latter clusters, we find that NGC 752 is characterized by a tight Li vs. Teff
distribution for solar-type stars, with no evidence for a Li spread as large as
the one observed in the solar age solar metallicity M 67. We discuss these
results in the framework of mixing mechanisms and Li depletion on the main
sequence (MS). We conclude that the development of a large scatter in Li
abundances in old open clusters might be an exception rather than the rule
(additional observations of old clusters are required), and that metallicity
variations of the order of ~0.2 dex do not affect Li depletion after the age of
the Hyades.


title:
Gamma-ray bursts and X-ray melting of material to form chondrules and
  planets

abstract:
  Chondrules are millimeter sized objects of spherical to irregular shape that
constitute the major component of chondritic meteorites that originate in the
region between Mars and Jupiter and which fall to Earth. They appear to have
solidified rapidly from molten or partially molten drops. The heat source that
melted the chondrules remains uncertain. The intense radiation from a gamma-ray
burst (GRB) is capable of melting material at distances up to 300 light years.
These conditions were created in the laboratory for the first time when
millimeter sized pellets were placed in a vacuum chamber in the white
synchrotron beam at the European Synchrotron Radiation Facility. The pellets
were rapidly heated in the X-ray and gamma-ray furnace to above 1400C melted
and cooled. This process heats from the inside unlike normal furnaces. The
melted spherical samples were examined with a range of techniques and found to
have microstructural properties similar to the chondrules that come from
meteorites. This experiment demonstrates that GRBs can melt precursor material
to form chondrules that may subsequently influence the formation of planets.
This work extends the field of laboratory astrophysics to include high power
synchrotron sources.


title:
The nuclear radio-optical properties of intermediate redshift FRII radio
  galaxies and quasars

abstract:
  We extend the study of the nuclei of 3CR objects as seen with the HST to
higher redshift FR II radio sources (0.4<z<0.6). Our results reflect what has
been found for FR II of lower redshift. The position of the nuclei on the plane
formed by optical and radio luminosities is related to their optical spectral
classification: the nuclei of both high and low excitation galaxies lie on the
correlation found for FRI sources, while broad-lined objects have a significant
optical excess. The nuclear properties of these sources are better understood
when considering the equivalent width of the [OIII] emission line with respect
to their optical luminosities. Even in the range of redshift considered here,
low excitation galaxies show peculiar nuclear properties, more similar to those
observed in FR I. This confirms that not all FRII are unified with quasars. Our
findings have important implications for the FRII-quasar unification scheme: by
reconsidering the classification of all 3CR radio galaxies with z<1 in the
light of their nuclear properties, we derive the opening angle of the obscuring
torus for different redshift bins. We find that the covering factor of the
obscuring structure decreases as redshift increases (theta ~ 44 deg for z<0.3
to theta ~ 56 deg for 0.5<z<1). We argue that this behavior may be interpreted
in the framework of the receding torus model, in which the opening angle of the
torus increases as the luminosity of the accretion disk around the central
black hole increases.


title:
High-energy observations of the state transition of the X-ray nova and
  black hole candidate XTE J1720-318

abstract:
  We report the results of extensive high-energy observations of the X-ray
transient and black hole candidate XTE J1720-318 performed with INTEGRAL,
XMM-Newton and RXTE. The source, which underwent an X-ray outburst in 2003
January, was observed in February in a spectral state dominated by a soft
component with a weak high-energy tail. The XMM-Newton data provided a high
column density Nh of 1.2*e22 cm^{-2} which suggests that the source lies at the
Galactic Centre distance. The simultaneous RXTE and INTEGRAL Target of
Opportunity observations allowed us to measure the weak and steep tail, typical
of a black-hole binary in the so-called High/Soft State. We then followed the
evolution of the source outburst over several months using the INTEGRAL
Galactic Centre survey observations. The source became active again at the end
of March: it showed a clear transition towards a much harder state, and then
decayed to a quiescent state after April. In the hard state, the source was
detected up to 200 keV with a power law index of 1.9 and a peak luminosity of
7*e36 erg s^{-1} in the 20-200 keV band, for an assumed distance of 8 kpc. We
conclude that XTE J1720-318 is indeed a new member of the black hole X-ray
novae class which populate our galactic bulge and we discuss its properties in
the frame of the spectral models used for transient black hole binaries.


title:
Core-Accretion Model Predicts Few Jovian-Mass Planets Orbiting Red
  Dwarfs

abstract:
  The favored theoretical explanation for giant planet formation -- in both our
solar system and others -- is the core accretion model (although it still has
some serious difficulties). In this scenario, planetesimals accumulate to build
up planetary cores, which then accrete nebular gas. With current opacity
estimates for protoplanetary envelopes, this model predicts the formation of
Jupiter-mass planets in 2--3 Myr at 5 AU around solar-mass stars, provided that
the surface density of solids is enhanced over that of the minimum-mass solar
nebula (by a factor of a few). Working within the core-accretion paradigm, this
paper presents theoretical calculations which show that the formation of
Jupiter-mass planets orbiting M dwarf stars is seriously inhibited at all
radial locations (in sharp contrast to solar-type stars). Planet detection
programs sensitive to companions of M dwarfs will test this prediction in the
near future.


title: An all-sky optical catalogue of radio / X-ray sources

abstract:
  We present an all-sky catalogue that aligns and overlays the ROSAT HRI, RASS,
PSPC and WGA X-ray catalogues and the NVSS, FIRST and SUMSS radio catalogues
onto the optical APM and USNO-A catalogues. Objects presented are those
APM/USNO-A optical objects which are calculated with >= 40% confidence to be
associated with radio/X-ray detections, or which are identified as known QSOs,
AGN or BL Lacs, totalling 501,761 objects in all, including 48,285 QSOs and
21,498 double radio lobe detections. For each radio/X-ray associated optical
object we display the calculated percentage probabilities of its being a QSO,
galaxy, star, or erroneous radio/X-ray association, plus any identification
from the literature. The catalogue includes 86,009 objects which were not
previously identified and which we list as being 40% to >99% likely to be a
QSO. As a byproduct of the construction of this catalogue, we are able to list
comprehensive ROSAT field shifts as determined by our whole-sky likelihood
algorithm, and also plate-by-plate photometric recalibration of the complete
APM and USNO-A2.0 optical catalogues, significantly improving accuracy for
objects of >15 mag. The catalogue is available wholly and in subsets at
http://quasars.org/qorg-data.htm


title: Ultrahigh Energy Cosmic Rays: New Physics or Old Physics?

abstract:
  We consider the advantages of and the problems associated with hypotheses to
explain the origin of ulthrahigh energy cosmic rays (UHECR: E > 10 EeV) and the
"trans GZK" cosmic rays (TGZK: E > 100 EeV), both through "old physics"
(acceleration in cosmic sources) and "new physics" (new particles, topological
defects, fat neutrino cross sections, Lorentz invariance violation).


title: A first XMM-Newton look at the relativistic double pulsar PSR J0737-3039

abstract:
  We present the results of a 50 ks long X-ray observation of the relativistic
double pulsar system PSR J0737-3039 obtained with the XMM-Newton satellite in
March 2004. The source has a soft spectrum (power law photon index =
3.5(+0.5,-0.3)) and a 0.2-10 keV luminosity of ~3x10^30 erg/s (assuming a
distance of 500 pc), consistent with the values derived from a previous Chandra
observation. No flux variations have been detected, implying the absence of
large orbital modulations. The high time resolution of the EPIC instrument has
allowed us to perform the first search for X-ray pulsations from this system.
The result was negative, with an upper limit of 60% on the pulsed fraction of
the 22 ms pulsar.


title: On a parity property in the thermal Sunyaev-Zel'dovich effect

abstract:
  The main issue in this paper is to discuss a parity property that appears in
the expressions for the distorted spectrum of the thermal Sunyaev-Zel'dovich
effect. When using the convolution integrals method involving scattering laws
we argue that the distorted spectrum contains a new term, which is an odd power
of the frequency. Such a term, absent in the conventional approaches, implies a
crossover frequency which differs in value form the ones reported in the
literature by a significant, in principle observable, amount. Also, such term
casts doubt on the demanding need of computing complicated relativistic
calculations. The relationship of our approach with the existing calculations
is discussed.


title:
Lithium-6 and Gamma Rays: Complementary Constraints on Cosmic-Ray
  History

abstract:
  The rare isotope 6Li is made only by cosmic rays, dominantly in alpha+alpha
fusion reactions with ISM helium. Consequently, this nuclide provides a unique
diagnostic of the history of cosmic rays in our Galaxy. The same hadronic
cosmic-ray interactions also produce high-energy gamma rays (mostly via neutral
pion production). Thus, hadronic gamma-rays and 6Li are intimately linked.
Specifically, 6Li directly encodes the local cosmic-ray fluence over cosmic
time, while extragalactic hadronic gamma rays encode an average cosmic-ray
fluence over lines of sight out to the horizon. We examine this link and show
how 6Li and gamma-rays can be used together to place important
model-independent limits on the cosmic-ray history of our Galaxy and the
universe. We first constrain gamma-ray production from ordinary Galactic cosmic
rays, using the local 6Li abundance. We find that the solar 6Li abundance
demands an accompanying extragalactic pionic gamma-ray intensity which exceeds
that of the entire observed EGRB by a factor of 2-6. Possible explanations for
this discrepancy are discussed. We then constrain Li production using recent
determinations of extragalactic gamma-ray background (EGRB). We note that
cosmic rays created during cosmic structure formation would lead to
pre-Galactic Li production, which would act as a "contaminant" to the
primordial 7Li content of metal-poor halo stars. We find the uncertainties in
the observed EGRB are so large that we cannot exclude a pre-Galactic Li which
is comparable to primordial 7Li. Our limits and their more model-dependent
extensions will improve significantly with additional observations of 6Li in
halo stars, and with improved measurements of the EGRB spectrum by GLAST.
(Abriged abstract)


title: L3CCD results in pure photon counting mode

abstract:
  Theoretically, L3CCDs are perfect photon counting devices promising high
quantum efficiency ($\sim$90%) and sub-electron readout noise ($\sigma$<0.1
e-). We discuss how a back-thinned 512x512 frame-transfer L3CCD (CCD97) camera
operating in pure photon counting mode would behave based on experimental data.
The chip is operated at high electromultiplication gain, high analogic gain and
high frame rate. Its performance is compared with a modern photon counting
camera (GaAs photocathode, QE $\sim$28%) to see if L3CCD technology, in its
current state, could supersede photocathode-based devices.


title:
Mapping ices in protostellar environments on 1000 AU scales:
  Methanol-rich ice in the envelope of Serpens SMM 4

abstract:
  We present VLT-ISAAC L-band spectroscopy toward 10 stars in SVS 4, a 30"x45"
dense cluster of pre-main sequence stars deeply embedded in the Serpens star
forming cloud. The ISAAC spectra are combined with archival imaging from UKIRT
and ISOCAM to derive accurate extinctions toward the SVS 4 stars. The data are
then used to construct a spatial map of the distribution of ice in front of the
cluster stars with an average angular resolution of 6" or 1500 AU, three orders
of magnitude better than previous maps. We show that water ice is present
throughout the region and confirm the presence of methanol ice with an
abundance of up to 25% relative to water. It is shown that methanol ice
maintains a very high abundance relative to H2 throughout SVS 4, but drops by
at least an order of magnitude only 75" away from SVS 4. The maps indicate that
some of the lines of sight toward the SVS 4 stars pass through the outer
envelope of the class 0 protostar SMM 4. The abundance of water ice relative to
the refractory dust component shows a sudden increase by 90% to (1.7+/-0.2) *
10^-4 relative to H2 at a distance of 5000 AU to the center of SMM 4. The water
ice abundance outside the jump remains constant at (9+/-1) * 10^-5. We suggest
that this is an indication of a significantly enhanced ice formation efficiency
in the envelopes of protostars. The depletion of volatile molecules in the
envelope of SMM 4 is discussed. In particular, it is found that up to 2/3 of
the depleted CO is converted into CO2 and CH3OH in the ice. Therefore, only 1/3
of the CO originally frozen out will return to the gas phase as CO upon warmup.


title: Backreaction of linear perturbations and dark energy

abstract:
  A simple discussion on the backreaction of inhomogeneities in cosmology,
focusing on the possibility that it could explain the present acceleration and
solve the coincidence problem.


title:
Tidal Interactions and Disruptions of Giant Planets on Highly Eccentric
  Orbits

abstract:
  We calculate the evolution of planets undergoing a strong tidal encounter
using smoothed particle hydrodynamics (SPH), for a range of periastron
separations. We find that outside the Roche limit, the evolution of the planet
is well-described by the standard model of linear, non-radial, adiabatic
oscillations. If the planet passes within the Roche limit at periastron,
however, mass can be stripped from it, but in no case do we find enough energy
transferred to the planet to lead to complete disruption. In light of the three
new extrasolar planets discovered with periods shorter than two days, we argue
that the shortest-period cases observed in the period-mass relation may be
explained by a model whereby planets undergo strong tidal encounters with
stars, after either being scattered by dynamical interactions into highly
eccentric orbits, or tidally captured from nearly parabolic orbits. Although
this scenario does provide a natural explanation for the edge found for planets
at twice the Roche limit, it does not explain how such planets will survive the
inevitable expansion that results from energy injection during tidal
circularization.


title: Extracting the rp-process from X-ray burst light curves

abstract:
  The light curves of type I X-ray bursts (XRBs) result from energy released
from the atmosphere of a neutron star when accreted hydrogen and helium ignite
and burn explosively via the rp-process. Since charged particle reaction rates
are both density and very temperature dependent, a simulation model must
provide accurate values of these variables to predict the reaction flow. This
paper uses a self-consistent one-dimensional model calculation with a constant
accretion rate of dM/dt=5e16g/s (0.045 Eddington) and reports on the detailed
rp-process reaction flow of a given burst.


title: On the Evolution and Gravitational Collapse of a Toroidal Vortex

abstract:
  The evolution and collapse of a gaseous toroidal vortex under the action of
self-gravitation are considered using the Hamiltonian mechanics approach. It is
shown that evolution occurs in three main stages separated by characteristic
time scales. First, a compression along the small radius to a quasi-equilibrium
state takes place, followed by a slower compression along the large radius to a
more stable compact vortex object. In the latter stage, the possibility of
effective scattering and ejection of particles along the vortex axis (jet
formation) is detected. As a result, mass, energy, and momentum losses take
place, and the vortex collapses.


title:
Scaling Laws for Dark Matter Halos in Late-Type and Dwarf Spheroidal
  Galaxies

abstract:
  Maximum disk mass models fitted to galaxy rotation curves are used to show
that dark matter (DM) halos in late-type and dwarf spheroidal (dSph) galaxies
satisfy well defined scaling laws. Halos in less luminous galaxies have smaller
core radii, higher central densities, and smaller central velocity dispersions.
Implications: (1) A single, continuous physical sequence of increasing mass
extends from the tiniest dSphs to the most luminous spirals. (2) The high DM
densities in dSph galaxies are normal for such dwarf galaxies. Since virialized
density depends on collapse redshift z, the smallest dwarfs formed about delta
z = 7 earlier than the biggest spirals. (3) The high DM densities of dSphs
implies that they are real galaxies formed from primordial density
fluctuations. They are not tidal fragments. (4) Because dwarf galaxies become
more numerous and more nearly dominated by DM as luminosity decreases, there
may be a large population of objects that are completely dark. Such objects are
a canonical prediction of cold DM theory. (5) The slopes of the DM parameter
correlations provide a measure on galactic mass scales of the slope n of the
power spectrum of primordial density fluctuations. Our results not yet
corrected for baryonic compression of DM give n = -1.9 +- 0.2. This is
consistent with cold DM theory.


title: Using Bars As Signposts of Galaxy Evolution at High and Low Redshifts

abstract:
  An analysis of the NICMOS Deep Field shows that there is no evidence of a
decline in the bar fraction beyond z~0.7, as previously claimed; both
bandshifting and spatial resolution must be taken into account when evaluating
the evolution of the bar fraction. Two main caveats of this study were a lack
of a proper comparison sample at low redshifts and a larger number of galaxies
at high redshifts. We address these caveats using two new studies. For a proper
local sample, we have analyzed 134 spirals in the near-infrared using 2MASS
(main results presented by Menendez-Delmestre in this volume) which serves as
an ideal anchor for the low-redshift Universe. In addition to measuring the
mean bar properties, we find that bar size is correlated with galaxy size and
brightness, but the bar ellipticity is not correlated with these galaxy
properties. The bar length is not correlated with the bar ellipticity. For
larger high redshift samples we analyze the bar fraction from the 2-square
degree COSMOS ACS survey. We find that the bar fraction at z~0.7 is ~50%,
consistent with our earlier finding of no decline in bar fraction at high
redshifts.


title: How Barred is the NIR Nearby Universe? An analysis using 2MASS

abstract:
  We determine a firm lower limit to the bar fraction of 0.58 in the nearby
universe using J+H+Ks-band images for 134 spirals from 2MASS. With a mean
deprojected semi-major axis of 5.1 kpc, and a mean deprojected ellipticity of
0.45 this local bar sample lays the ground work for studies on bar formation
and evolution at high redshift.


title: Reaction Rate Sensitivity of the gamma-Process Path

abstract:
  The location of the (gamma,p)/(gamma,n) and (gamma,alpha)/(gamma,n) line at
gamma-process temperatures is discussed, using recently published reaction
rates based on global Hauser-Feshbach calculations. The results can directly be
compared to previously published, classic gamma-process discussions. The nuclei
exhibiting the largest sensitivity to uncertainties in nuclear structure and
reaction parameters are specified.


title: Black Hole Masses of High-Redshift Quasars

abstract:
  Black-hole masses of distant quasars cannot be measured directly, but can be
estimated to within a factor 3 to 5 using scaling relationships involving the
quasar luminosity and broad-line width. Why such relationships are reasonable
is summarized. The results of applying scaling relationships to data of quasars
at a range of redshifts (z <= 6.3) are presented. Luminous quasars typically
have masses of order 1 billion solar masses even at the highest redshifts. The
fact that such massive black holes appear as early as at z ~ 6 indicate that
black holes form very early or build up mass very fast.


title:
Neutron Capture in the r-Process -- Do We Know Them And Does It Make Any
  Difference?

abstract:
  The r-process involves neutron-rich nuclei far off stability for which no
experimental cross sections are known. Therefore, one has to rely on theory
which might be prone to considerable uncertainties far off stability. To
investigate the impact of such uncertainties, nucleosynthesis in hot bubble
models followed completely from high-temperature NSE to low-temperature neutron
capture freeze-out were calculated with largely varied rates. Due to the
(n,gamma)-(gamma,n) equilibrium established at the onset of the r-process, only
late-time neutron captures are important which mainly modify the abundances
around the third r-process peak.


title:
Planetary Nebulae as Probes of the Chemical Evolution of Dynamically Hot
  Systems

abstract:
  The measurement of chemical abundances in planetary nebulae in nearby
galaxies is now relatively straightforward. The challenge is to use these
chemical abundances to infer the chemical evolution of their host galaxies. At
this point, our understanding of chemical evolution based upon planetary
nebulae in galaxies without star formation is strongly coupled to our
understanding of the relationship between the chemical abundances in stars and
planetary nebulae in the Milky Way bulge. Supposing that the same relation
holds in all systems where star formation ceased long ago, these systems follow
a metallicity-luminosity relation that is displaced to higher chemical
abundances compared to that found for dwarf irregular galaxies. A more
efficient enrichment process appears to be required as part of the explanation
for this shift, in addition to the inevitable fading of these galaxies.


title: Shocked similarity collapses and flows in star formation processes

abstract:
  We propose self-similar shocked flow models for certain dynamical evolution
phases of young stellar objects (YSOs), `champagne flows' of H {\sevenrm II}
regions surrounding OB stars and shaping processes of planetary nebulae (PNe).
We analyze an isothermal fluid of spherical symmetry and construct families of
similarity shocked flow solutions featured by: 1. either a core expansion with
a finite central density or a core accretion at constant rate with a density
scaling $\propto r^{-3/2}$; 2. a shock moving outward at a constant speed; 3. a
preshock gas approaching a constant speed at large $r$ with a density scaling
$\propto r^{-2}$. In addition to testing numerical codes, our models can
accommodate diverse shocked flows with or without a core collapse or outflow
and an envelope expansion or contraction. As an application, we introduce our
model analysis to observations of Bok globule B335.


title: Multiverses and Cosmology: Philosophical Issues

abstract:
  The idea of a multiverse -- an ensemble of universes or universe domains --
has received increasing attention in cosmology, both as the outcome of the
originating process that generated our own universe, and as an explanation for
why our universe appears to be fine-tuned for life and consciousness. Here we
carefully consider how multiverses should be defined, stressing the distinction
between the collection of all possible universes, and ensembles of really
existing universes, which are essential for an anthropic argument. We show that
such realised multiverses are by no means unique, and in general require the
existence of a well-defined and physically motivated distribution function on
the space of all possible universes. Furthermore, a proper measure on these
spaces is also needed, so that probabilities can be calculated. We then discuss
several other major physical and philosophical problems which arise in the
context of ensembles of universes, including the emergence and causal
effectiveness of self-consciousness, realized infinities, and fine- tuning, or
the apparent need for very special initial conditions for our universe --
whether they or generalized generic primordial conditions are more fundamental.
Then we briefly summarise scenarios like chaotic inflation, which suggest how
ensembles of universe domains may be generated, and point out that the
regularities which must underlie any systematic description of truly disjoint
multiverses must imply some kind of common generating mechanism. Finally, we
discuss the issue of testability, which underlies the question of whether
multiverse proposals are really scientific propositions.


title: An XSPEC model to explore spectral features from black-hole sources

abstract:
  We report on a new general relativistic computational model enhancing, in
various respects, the capability of presently available tools for fitting
spectra of X-ray sources. The new model is intended for spectral analysis of
black-hole accretion discs. Our approach is flexible enough to allow easy
modifications of intrinsic emissivity profiles. Axial symmetry is not assumed,
although it can be imposed in order to reduce computational cost of data
fitting. The main current application of our code is within the XSPEC
data-fitting package, however, its applicability goes beyond that: the code can
be compiled in a stand-alone mode, capable of examining time-variable spectral
features and doing polarimetry of sources in the strong-gravity regime. Basic
features of our approach are described in a separate paper (Dovciak, Karas &
Yaqoob 2004). Here we illustrate some of its applications in more detail. We
concentrate ourselves on various aspects of line emission and Compton
reflection, including the current implementation of the lamp-post model as an
example of a more complicated form of intrinsic emissivity.


title: Mapping the Stellar Dynamics of M31

abstract:
  Using the Planetary Nebula Spectrograph, we have observed and measured the
velocities for some 2764 PNe in the disk and halo of the Andromeda galaxy.
Preliminary analysis using a basic ring model shows a rotation curve in good
agreement with that obtained from HI data out to ~20kpc. Some substructure has
also been detected within the velocity field, which can be modeled as the
continuation of the tidal-remnant known as the Southern Stream, as it passes
through Andromeda's disk.


title: Observation of the Molecular Zeeman Effect in the G band

abstract:
  Here we report on the first observational investigation of the Zeeman effect
in the G band around 4305 A. Our spectropolarimetric observations of sunspots
with the Zurich Imaging Polarimeter at the IRSOL facility confirm our previous
theoretical prediction that the molecular Zeeman effect produces measurable
circular polarization signatures in several CH lines that are not overlapped
with atomic transitions. We also find both circular and linear polarization
signals produced by atomic lines whose wavelengths lie in the G band spectral
region. Together, such molecular and atomic lines are potentially important for
empirical investigations on solar and stellar magnetism. For instance, a
comparison between observed and calculated Stokes profiles suggests that the
thermodynamical and/or magnetic properties of the photospheric regions of
sunspot umbrae are horizontally structured with a component that might be
associated with umbral dots.


title:
XMM-Newton observations of the supernova remnant RX J1713.7-3946 and its
  central source

abstract:
  We present new results coming from the observations of the supernova remnant
(SNR) RX J1713.7--3946 (also G347.3--0.5) performed in five distinct pointings
with the EPIC instrument on board the satellite XMM-Newton. RX J1713.7--3946 is
a shell-type SNR dominated by synchrotron radiation in the X-rays. Its emission
(emission measure and photon index) as well as the absorption along the
line-of-sight has been characterized over the entire SNR. The X-ray mapping of
the absorbing column density has revealed strong well constrained variations
(0.4 10^22 cm^-2 < NH < 1.1 10^22 cm^-2) and, particularly, a strong absorption
in the southwest. Moreover, there are several clues indicating that the shock
front of RX J1713.7--3946 is impacting the clouds responsible for the
absorption as revealed for instance by the positive correlation between X-ray
absorption and X-ray brightness along the western rims. The CO and HI
observations show that the inferred cumulative absorbing column densities are
in excellent agreement with the X-ray findings in different places of the
remnant on condition that the SNR lies at a distance of 1.3 +/- 0.4 kpc,
probably in the Sagittarius galactic arm, instead of the commonly accepted
value of 6 kpc. An excess in the CO emission is found in the southwest
suggesting that the absorption is due to molecular clouds. A search for OH
masers in the southwestern region has been unsuccessful, possibly due to the
low density of the clouds. The X-ray mapping of the photon index has also
revealed strong variations (1.8 < Gamma < 2.6). [See the article for the entire
abstract]


title: Dynamical Masses of the Binary Brown Dwarf GJ 569Bab

abstract:
  We have obtained new images and high-resolution (R ~ 22400) near-infrared
(1.2400-1.2575 micron) spectra of each component of the brown dwarf binary GJ
569Bab using the Adaptive Optics facility of the Keck II telescope and the
NIRSPEC spectrometer. These data have allowed us to improve the determination
of the astrometric orbit and to measure radial velocities of the components. We
have used the astrometric and spectroscopic measurements to derive the
dynamical mass of each brown dwarf and the systemic velocity of the pair by
means of a chi^2 fitting technique. From various considerations, the mass of
each component is likely in the range 0.034-0.070 Msol (GJ 569Bb) and
0.055-0.087 Msol (GJ 569Ba). This implies that the mass ratio, q, of the binary
is greater than 0.4, being the most likely value q = 0.75-0.85. Adopting 0.072
Msol as the most conservative location of the substellar limit for solar
metallicity, our analysis confirms GJ 569Bb as the first genuine brown dwarf
known without any theoretical assumption. We have compared the dynamical masses
of GJ 569Ba and Bb, and their effective temperatures and luminosities, to the
predictions of state-of-the-art theoretical evolutionary isochrones, finding
that models exhibit good performance in the regime of high substellar masses if
the binary is about a few hundred million years old. However, the surface
gravities of GJ 569Ba (M8.5V) and Bb (M9V) derived from our spectral analysis
(the observed data have been compared to the latest synthetic spectra) appear
to be smaller than the values provided by the evolutionary models.


title:
The vertical structure of T Tauri accretion disks II. Physical
  conditions in the disk

abstract:
  We present a self-consistent analytical model for the computation of the
physical conditions in a steady quasi-Keplerian accretion disk. The method,
based on the thin disk approximation, considers the disk as concentric
cylinders in which we treat the vertical transfer as in a plane-parallel
medium. The formalism generalizes a work by Hubeny (1990), linking the disk
temperature distribution to the local energy dissipation and leads to
analytical formulae for the temperature distribution which help to understand
the behaviour of the radiation propagated inside the disks. One of the main
features of our new model is that it can take into account many heating
sources. We apply the method first to two sources: viscous dissipation and
stellar irradiation. We show that other heating sources like horizontal
transfer or irradiation from the ambiant medium can also be taken into account.
Using the analytical formulation in the case of a modified Shakura & Sunyaev
radial distribution that allow the accretion rate to be partly self-similar in
the inner region, and, for an alpha and beta prescription of the viscosity, we
obtain two-dimensional maps of the temperature, pressure and density in the
close environment of low mass young stars. We use these maps to derive the
observational properties of the disks such as spectral energy distributions,
high resolution spatial images or visibilities in order to underline their
different behaviours under different input models.


title:
The discovery of hard X-ray emission in the persistent flux of the Rapid
  Burster

abstract:
  We report the first detection with INTEGRAL of persistent hard X-ray emission
(20 to 100 keV) from the Rapid Burster (MXB 1730-335), and describe its full
spectrum from 3 to 100 keV. The source was detected on February/March 2003
during one of its recurrent outbursts. The source was clearly detected with a
high signal to noise ratio during the single pointings and is well
distinguished from the neighboring source GX 354-0. The 3 - 100 keV X-ray
spectrum of the persistent emission is well described by a two-component model
consisting of a blackbody plus a power-law with photon index ~ 2.4. The
estimated luminosity was ~ 8.5x10^{36} erg/s in the 3 - 20 keV energy band and
\~ 1.3x10^{36} erg/s in the 20 - 100 keV energy range, for a distance of 8 kpc.


title:
High velocity bipolar outflow and disk-like envelope in the carbon star
  V Hya

abstract:
  Using the partially completed Submillimeter Array with five antennas, we have
observed the CO J=2-1 and 3-2 emission from the envelope surrounding the carbon
star V Hya. The high-angular resolution (2"-4") maps show that V Hya is
powering a bipolar molecular jet having an extreme velocity of 70-185 km/s. The
axis of this high velocity jet is perpendicular to the major axis of the
flattened disk-like envelope, which is expanding with a velocity of ~16
km/s.There is a third kinematic component, a medium-velocity wind having a
deprojected velocity of 40-120 km/s moving along the disk plane. Both the high
velocity jet and the medium velocity wind have a dynamical time scale of a few
hundred years. The flattened structure and the collimated jet observed in V Hya
suggests that the formation of asymmetrical structure proceeds while the
central star is still in the AGB phase


title:
Resolving X-ray sources from B-stars spectroscopically: The example of
  mu Lep

abstract:
  We present high-resolution X-ray observations of the chemically peculiar
late-type B-star: mu Lep. However, we find spectroscopic and astrometric
evidence, which show that the X-rays are not traced back to the B-star itself,
but rather to a previously unresolved companion: mu Lep-B, whose X-ray spectrum
resembles that of a coronally active source. We discuss the possibility that mu
Lep-B is a pre-main-sequence companion, most likely of the non-accreting
magnetically-active type.


title:
Detecting high-energy neutrinos from microquasars with the ANTARES
  telescope

abstract:
  The ANTARES project aims at the construction of a neutrino telescope 2500 m
below the surface of the Mediterranean sea, close to the southern French coast.
The apparatus will consist of a 3D array of photomultiplier tubes, which
detects the Cherenkov light emitted by upward going neutrino-induced muons.
High-energy neutrinos may be produced in powerful cosmic accelerators, such as,
gamma-ray bursters, active galactic nuclei, supernova remnants, and
microquasars. We have estimated the event rate in ANTARES of neutrinos coming
from these sources, and particularly for a microquasar model, and found that
for some of these sources the detection rate can be up to several events per
year.


title:
The Abundance of Elements in Cool Stars, as Determined from
  High-Resolution, 1-5 Micron Spectroscopy

abstract:
  We review the field of abundance determinations of elements in cool stars,
with special interest paid to determinations based on analyses of
high-resolution, 1-5 micron spectra. We discuss the current status, problems,
and challenges of exploring high-resolution, near-infrared spectra. In
particular, advantages and drawbacks are pointed out. A few examples of
current, chemical-abundance determinations are high-lighted and, finally, we
discuss the development


title: Was the Highest Energy Cosmic Ray a Photon?

abstract:
  The hypothetical photonic origin of the most energetic air shower detected by
the Fly's Eye experiment is discussed. The method used for the analysis is
based on Monte Carlo simulations including the effect of precascading of
ultra-high energy (UHE) photons in the geomagnetic field. The application of
this method to data expected from the Pierre Auger Observatory is discussed.
The importance of complementing the southern Auger location by a northern site
for UHE photon identification is pointed out.


title: INTEGRAL observations of five sources in the Galactic Center region

abstract:
  A number of new X-ray sources (IGR J17091-3624, IGR/XTE J17391-3021, IGR
J17464-3213 (= XTE J17464-3213 = H 1743-322), IGR J17597-2201, SAX/IGR
J18027-2017) have been observed with the INTEGRAL observatory during ultra deep
exposure of the Galactic Center region in August-September 2003. Most of them
were permanently visible by the INTEGRAL at energies higher than $\sim 20$ keV,
but IGR/XTE J17391-3021 was observed only during its flaring activity with a
flux maximum of $\sim120$ mCrab. IGR J17091-3624, IGR J17464-3213 and IGR
J17597-2201 were detected up to $\sim 100$-150 keV. In this paper we present
the analysis of INTEGRAL observations of these sources to determine the nature
of these objects. We conclude that all of them have a galactic origin. Two
sources are black hole candidates (IGR J17091-3624 and IGR J17464-3213), one is
an LMXB neutron star binary (presumably an X-ray burster) and two other sources
(IGR J17597-2201 and SAX/IGR J18027-2017) are neutron stars in high mass
binaries; one of them (SAX/IGR J18027-2017) is an accreting X-ray pulsar.


title: Secular Evolution and the Formation of Pseudobulges in Disk Galaxies

abstract:
  We review internal processes of secular evolution in galaxy disks,
concentrating on the buildup of dense central features that look like
classical, merger-built bulges but that were made slowly out of disk gas. We
call these pseudobulges. As an existence proof, we review how bars rearrange
disk gas into outer rings, inner rings, and gas dumped into the center. In
simulations, this gas reaches high densities that plausibly feed star
formation. In the observations, many SB and oval galaxies show central
concentrations of gas and star formation. Star formation rates imply plausible
pseudobulge growth times of a few billion years. If secular processes built
dense central components that masquerade as bulges, can we distinguish them
from merger-built bulges? Observations show that pseudobulges retain a memory
of their disky origin. They have one or more characteristics of disks: (1)
flatter shapes than those of classical bulges, (2) large ratios of ordered to
random velocities indicative of disk dynamics, (3) small velocity dispersions,
(4) spiral structure or nuclear bars in the bulge part of the light profile,
(5) nearly exponential brightness profiles, and (6) starbursts. These
structures occur preferentially in barred and oval galaxies in which secular
evolution should be rapid. So the cleanest examples of pseudobulges are
recognizable. Thus a large variety of observational and theoretical results
contribute to a new picture of galaxy evolution that complements hierarchical
clustering and merging.


title: The First Discovery of a Wide Binary Brown Dwarf

abstract:
  I present observations of a new faint double, 2MASS J11011926-7732383AB,
toward the Chamaeleon I star-forming region. From optical and near-infrared
images of the pair, I measure a separation of 1.44" and extract RIJHK_s
photometry of the components (I_A=17.21, dI=1.07, K_s A=11.97, dK_s=0.84). I
use resolved optical spectroscopy to derive spectral types of M7.25 and M8.25
for the A and B components, respectively. Based on the strengths of
gravity-sensitive features in these data, such as the Na I and K I absorption
lines, I conclude that these objects are young members of Chamaeleon I rather
than field stars. The probability that this pair is composed of unrelated
late-type members of Chamaeleon I is low enough (~5x10^-5) to definitively
establish it as a binary system. After estimating extinctions, effective
temperatures, and bolometric luminosities for the binary components, I place
them on the H-R diagram and infer their masses with the evolutionary models of
Chabrier and Baraffe, arriving at substellar values of 0.05 and 0.025 M_sun.
The projected angular separation of this system corresponds to 240 AU at the
distance of Chamaeleon I, making it the first known binary brown dwarf with a
separation greater than 20 AU. This demonstration that brown dwarfs can form in
fragile, easily disrupted configurations is direct evidence that the formation
of brown dwarfs does not require ejection from multiple systems or other
dynamical effects. It remains possible that ejection plays a role in the
formation of some brown dwarfs, but it is not an essential component according
to these observations.


title: Low-mass substellar candidates in NGC 2264

abstract:
  NGC 2264 is a young (3 Myr), populous star forming region for which our
optical studies have revealed a very high density of potential brown dwarf (BD)
candidates - 236 in less than 1 sq. deg. - from the substellar limit down to 20
Mjup. Candidate BD were first selected using wide field (I,z) band imaging with
CFHT/12K, by reference to current theoretical isochrones. Subsequently, around
50% of the I,z sample were found to have near-infrared (2MASS) photometry,
allowing further selection by comparison with the location of DUSTY isochrones
in colour-colour diagrams involving combinations of IJHK colours. After
rejection of objects with only upper limits to J, six candidates were selected
from the I-K,J-H diagram which afforded the best separation of candidate and
field objects; of these, 2 also lie close to the model predictions in the
I-J,I-K and I-J,H-K plots. After dereddening, all six remain probable very
low-mass NGC 2264 members, in spite of their low Av, while a different group of
objects are shown to be highly reddened background giants. A further three
brighter (at $I$) objects selected by their I-J,I-K colours, lie at the
substellar limit and are likely cluster objects, as are 2 intermediate mass
objects selected by their I-K and H-K colours. These objects potentially
constitute a hitherto unknown population of young, low-mass BD in this region;
only slighty deeper observations could reveal a new laboratory for the study of
near-planetary-mass objects.


title: Globular clusters and the formation of the outer Galactic halo

abstract:
  Globular clusters in the outer halo (R_gc > 15 kpc) are found to be
systematically fainter than those at smaller Galactocentric distances. Within
the outer halo the compact clusters with half-light radii R_h < 10 pc are only
found at R_gc < 40 kpc, while on the other hand the larger clusters with R_h >
10 pc are encountered at all Galactocentric distances. Among the compact
clusters with R_h < 10 pc that have R_gc > 15 kpc, there are two objects with
surprisingly high metallicities. One of these is Terzan 7, which is a companion
of the Sagittarius dwarf. The other is Palomar 1. The data on these two objects
suggests that they might have had similar evolutionary histories. It is also
noted that, with one exception, luminous globular clusters in the outer halo
are all compact whereas faint ones may have any radius. This also holds for
globular clusters in the LMC, SMC and Fornax dwarf. The lone exception is the
large luminous globular NGC 2419. Possibly this object is not a normal globular
cluster, but the stripped core of a former dwarf spheroidal. In this respect it
may resemble Omega Centauri.


title: In-orbit performance of the EPIC-MOS detectors on XMM-Newton

abstract:
  XMM-Newton was launched into space on a highly eccentric 48 hour orbit on
December 10th 1999. XMM-Newton is now in its fifth year of operation and has
been an outstanding success, observing the Cosmos with imaging, spectroscopy
and timing capabilities in the X-ray and optical wavebands. The EPIC-MOS CCD
X-ray detectors comprise two out of three of the focal plane instruments on
XMM-Newton. In this paper we discuss key aspects of the current status and
performance history of the charge transfer ineffiency (CTI), energy resolution
and spectral redistribution function (rmf) of EPIC-MOS in its fifth year of
operation.


title: The PNLF distance to the Sculptor Group galaxy NGC 55

abstract:
  We identified 21 new Planetary Nebula (PN) candidates in the Sculptor Group
galaxy NGC 55. We determined a most likely distance of 2.00 +/- 0.2 Mpc using
the Planetary Nebulae Luminosity Function (PNLF) method. The distance to NGC 55
is larger than previously determined distances, which means that the Sculptor
Group is a bit further away from the Local Group than previously thought. The
distance to NGC 55 is again similar to the distance of NGC 300, adding support
to the suggestion that these galaxies form a bound pair.


title: The Energy Density of "Wound" Fields in a Toroidal Universe

abstract:
  The observational limits on the present energy density of the Universe allow
for a component that redshifts like $1/a^2$ and can contribute significantly to
the total. We show that a possible origin for such a contribution is that the
universe has a toroidal topology with "wound" scalar fields around its cycles.


title:
Variability of X-ray pulsars in a hard energy band observed with
  INTEGRAL

abstract:
  We present the first results of the observations of the X-ray pulsars LMC
X-4, 4U0352+309 and EXO1722-363 performed with the INTEGRAL observatory. The
LMC X-4 was investigated during the whole superorbital cycle ($\sim$30 days)
and it was found that its period was not stable at this time scale. We detected
a variable X-ray flux (18-60 keV) from the pulsar EXO1722-363, which could be
connected with the orbital motion in the binary system. A more accurate
position and the estimate of the orbital period for this source are reported.
We also investigated a hard X-ray spectrum of 4U0352+309 (X Persei) measured
with INTEGRAL and report the detection of the cyclotron absorption line at
about 29 keV.


title:
The nearest extreme starburst: bubbles, young star clusters, and outflow
  in NGC 3256

abstract:
  In this Work we report, for the extreme starburst in the IR merger NGC 3256:
(i) The detection of 4 galactic bubbles, associated with SN explosions.(ii) The
first analysis of the spatial distribution of young star clusters (YSC)
candidates.(iii) The kinematic study of the ionized gas in the core of of the
main optical nucleus, performed with HST STIS spectra. The shape of the
rotation curve and the emission line profile could be explained by the presence
in the core of YSC with outflow.


title: The Baryon Content of the Local Intergalactic Medium

abstract:
  We describe our surveys of low column density Lyman-alpha absorbers [N(HI) =
10^(12.5-16.0) cm^-2], which show that the warm photoionized IGM contains 30%
of all baryons at z < 0.1. This fraction is consistent with cosmological
simulations, which also predict that an additional 20-40% of the baryons reside
in hotter 10^(5-7) K gas, the warm-hot IGM (WHIM). The observed line density of
Lya absorbers, dN/dz = 170 for N(HI) > 10^(12.8) cm^-2, is dominated by
low-N(HI) systems that exhibit slower redshift evolution than those with N(HI)
>10^(14). HST/FUSE surveys of OVI absorbers, together with recent detections of
O VII with Chandra and XMM/Newton, suggest that 20-70% of all baryons could
reside in the WHIM, depending on its assumed abundance (O/H = 10% solar). At
the highest column densities, N(HI) > 10^(20.3), the damped Lya systems are
often identified with gas-rich disks of galaxies over a large range in
luminosities (0.03-1 L*) and morphologies. Lyman-limit systems [N(HI) =
10^(17.3-20.3)] appear to be associated with bound, bright (0.1-0.3 L*) galaxy
halos. The Lya absorbers with N(HI) = 10^(13-16) cm^-2 are associated with
filaments of large-scale structure in the galaxy distribution, although some
may arise in unbound winds from dwarf galaxies. Our discovery that ~20% of
low-z Lya absorbers reside in galaxy voids suggests that a substantial fraction
of baryons may be entirely unrelated to galaxies. In the future, Hubble (and
FUSE) can provide a census of the local baryons and the distribution of heavy
elements in the IGM. These studies can be conducted quite efficiently if NASA
can install the Cosmic Origins Spectrograph (COS) on Hubble, allowing an
order-of-magnitude improvement in throughput and a comparable increase in our
ability to study the IGM.


title: Enhanced Big Rip without Conventional Dark Energy

abstract:
  A modified Friedmann equation which arises in an extension of general
relativity which accommodates a time-dependent fundamental length $L(t)$ leads
to cosmological models where the scale factor diverges with an essential
singularity at a finite future time. Such models have no dark energy in the
conventional sense of energy possessing a truly simple pressure-energy
relationship. Data on supernovae restrict the time from the present until the
Rip to be generically longer than the current age of the Universe.


title:
The X-ray Jet of 3C 120: Evidence for a Non-standard Synchrotron
  Spectrum

abstract:
  We report on archival data from the Chandra X-ray Observatory for the radio
jet of 3C120. We consider the emission process responsible for the X-rays from
4 knots using spectra constructed from radio, optical, and X-ray intensities.
While a simple synchrotron model is adequate for three of the knots, the fourth
('k25'), which was previously detected by ROSAT and is now well resolved with
Chandra, still represents a problem for the conventional emission processes.
If, as we argue, the flat X-ray spectra from two parts of k25 are synchrotron
emission, then it appears that either the emission comes from an electron
distribution spectrally distinct from that responsible for the radio emission,
or at the highest electron energies, there is a significant deviation from the
power law describing the electron distribution at lower energies.


title:
Identification of a DO white dwarf and a PG1159 star in the ESO SN Ia
  progenitor survey (SPY)

abstract:
  We present high-resolution VLT spectra of a new helium-rich DO white dwarf
and a new PG1159 star, which we identified in the ESO SPY survey. We performed
NLTE model atmosphere analyses and found that the PG1159 star is a low-gravity,
extremely hot (Teff=160,000K, logg=6) star, having a carbon-helium dominated
atmosphere with considerable amounts of oxygen and neon (He=38%, C=54%, O=6%,
Ne=2% by mass). It is located within the planetary nebula nuclei instability
strip, hence, future searches for an associated PN as well as for stellar
pulsations might be successful. The DO white dwarf is a unique object. From the
relative strength of neutral and ionized helium lines we found Teff approx.
60,000K, however, the HeII lines are extraordinarily strong and cannot be
fitted by any model. Similar problems were encountered with hot subdwarfs and
white dwarfs showing signatures of a super-hot wind. The reason is unknown.


title:
Identification of neon in FUSE and VLT spectra of extremely hot
  hydrogen-deficient (pre-) white dwarfs

abstract:
  One of the strongest absorption lines observed in far-ultraviolet FUSE
spectra of many PG1159 stars remained unidentified up to now. We show that this
line, located at 973.3A, stems from NeVII. We also present new optical
high-resolution spectra of PG1159 stars, obtained with the ESO VLT, which cover
the NeVII 3644A line and a newly identified NeVII multiplet in the 3850-3910A
region. We compare the observed neon lines with NLTE models and conclude a
substantial neon overabundance in a number of objects. Although a detailed
analysis is still to be performed in order to compare quantitatively the
abundances with evolutionary theory predictions, this corroborates the idea
that the PG1159 stars and their immediate progenitors, the [WC]-type nuclei of
planetary nebulae, display intershell matter of their precursor AGB stars.
Possibly as the consequence of a late He-shell flash, H-deficient and
(s-processed) Fe-depleted matter, that is strongly enriched by
3-alpha-processed elements (C, O, Ne), is dredged up to the surface. Hence, a
detailed study of the element abundance patterns in these peculiar stars gives
the unique possibility to probe mixing and nucleosynthesis processes in the
precursor AGB stars.


title:
Fast Wave Polarization, Charge Horizons and the Time Evolution of
  Force-Free Magnetospheres

abstract:
  Numerical simulations of force-free, degenerate (ffde)pulsar and black hole
magnetospheres are often based on 1-D characteristics. In particular, the
plasma wave polarizations that can be propagated along the 1-D characteristics
determine the time evolution of the entire system. There are two sets of
characteristics,corresponding to the fast and Alfven modes. The fast wave is
generally considered to be a transverse light wave, however recently it has
been claimed that light-like fast waves can transport a longitudinal electric
polarization, $E_{\parallel}$, at the speed of light. The implication is quite
profound if true, namely that the wrong information has been propagated along
the fast characteristics in all previous simulations of force-free
magnetospheres. It is shown in this Letter that the light-like fast waves must
be transverse and previous simulations are valid. This result is demonstrated
by means of a fundamental physical principle (associated with the fact that
particles cannot flow faster than the speed of light), there exists a charge
horizon in ffde magnetospheres. It is shown that the Alfven critical surfaces
in a ffde magnetosphere are both charge and particle horizons, i.e. one way
membranes that do not permit traversal by charges nor particles anti-directed
to the bulk flow. Since the propagation of a discontinuous change in
$E_{\parallel}$ requires a physical surface charge on the wave-face, it is also
a one-way membrane for longitudinally polarized waves. Besides justifying
previous ffde simulations this result also invalidates previous claims that
fast waves can radiate $E_{\parallel}$ from the event horizon of a black hole.


title: On the Origin of S0 Galaxies

abstract:
  I will review the basic properties of S0 galaxies in the local Universe in
relation to both elliptical and spiral galaxies, their neighbours on the Hubble
sequence, and also in relation to dwarf spheroidal (dSph) galaxies. This will
include colours, luminosities, spectral features, information about the age and
metallicity composition of their stellar populations and globular clusters,
about their ISM content, as well as kinematic signatures and their implications
for central black hole masses and past interaction events, and the number
ratios of S0s to other galaxy types in relation to environmental galaxy
density. I will point out some caveats as to their morphological discrimination
against other classes of galaxies, discuss the role of dust and the wavelength
dependence of bulge/disk light ratios. These effects are of importance for
investigations into the redshift evolution of S0 galaxies -- both as individual
objects and as a population. The various formation and transformation scenarios
for S0 and dSph galaxies will be presented and confronted with the available
observations.


title: Host Galaxies of Gamma-Ray Bursts and their Cosmological Evolution

abstract:
  We use numerical simulations of large scale structure formation to explore
the cosmological properties of Gamma-Ray Burst (GRB) host galaxies. Among the
different sub-populations found in the simulations, we identify the host
galaxies as the most efficient star-forming objects, i.e. galaxies with high
specific star formation rates. We find that the host candidates are low-mass,
young galaxies with low to moderate star formation rate. These properties are
consistent with those observed in GRB hosts, most of which are sub-luminous,
blue galaxies. Assuming that host candidates are galaxies with high star
formation rates would have given conclusions inconsistent with the
observations. The specific star formation rate, given a galaxy mass, is shown
to increase as the redshift increases. The low mass of the putative hosts makes
them difficult to detect with present day telescopes and the probability
density function of the specific star formation rate is predicted to change
depending on whether or not these galaxies are observed.


title:
Star Formation in Galaxy Mergers: Scaling up a universal process or a
  violent mode of SF?

abstract:
  I briefly review some measures of star formation rates in galaxies and
discuss their respective uncertainties before outlining the range of star
formation rates encountered in starbursts from isolated dwarf through massive
gas-rich interacting systems. I present our current understanding of molecular
cloud masses and structures and on star formation processes and efficiencies in
starburst and interacting galaxies. Star cluster formation is an important mode
of star formation, in particular in strong star formation regimes. I discuss
the role of star clusters and their properties in helping us assess the
question if star formation is a universal process allowing for considerable
scaling or if there's two different regimes for normal and violent SF.


title: 3D outer bulge structure from near infrared star counts

abstract:
  We attempt to study the characteristics of the different stellar populations
present in the Galactic central region. A Monte Carlo method is used to
simultaneously fit 11 thin disc and triaxial outer bulge density parameters on
(Ks,J-Ks) star count data in almost 100 windows from the DENIS near infrared
large scale survey at -8 deg < l< 12 deg and -4 deg < b < 4 deg. Various bulge
density profiles and luminosity functions were tested uing a population
synthesis scheme. The best models, selected by a maximum likelihood test, give
the following description: the outer bulge is proxy, prolate, and oriented
10.6+/-3 deg with respect to the Sun-center direction. It seems that the main
bulge population is not older than 10 Gyr, but this preliminary result needs
further work to be confirmed. A significant central hole is found in the middle
of the thin disc. We discuss these results in regard to previous findings and
the scenario of bulge formation.


title: The Orbit and Albedo of Transneptunian Binary 1997 CQ29

abstract:
  We have measured the separations and position angles of the two components of
the binary transneptunian object 1997 CQ29 at eight epochs. From these data we
are able to constrain the orbit and mass of this binary system. The best
fitting orbit has an orbital period of P = 312+/-3 days. The orbital
eccentricity is e = 0.45+/-0.03 and the semimajor axis is a = 8,010+/-80 km.
The mass of the system is surprisingly low at 0.42+/-0.02 x 10^18 kg. To
account for the observed brightness consistent with the low mass and a range of
plausible densities, the geometric albedo must be very high; for an assumed
density of 1000 kg m^-3 we find a red geometric albedo of p_R = 0.37, an order
of magnitude higher than has been generally assumed for transneptunian objects.
If objects with comparably high albedos are common in the Kuiper belt,
estimates of the mass of the belt must be significantly reduced. The semimajor
axis of 1997 CQ29's orbit is 2.8% of the Hill radius of the primary, a value
strikingly similar to this same ratio in other transneptunian binaries,
main-belt binaries, and regular satellite systems.