title: Cosmographic evaluation of deceleration parameter using SNe Ia data

abstract:
  The apparent magnitude-redshift data of SNe Ia call for modifications in the
standard model energy densities. Under the circumstance that this modification
cannot be limited to the addition of a mere cosmological constant, a serious
situation has emerged in cosmology, in which the energy densities in the
universe have become largely speculative. In this situation, an equation of
state of the form p=w \rho itself is not well-motivated. In this paper, we
argue that the reasonable option left is to make a model-independent analysis
of SNe data, without reference to the energy densities. In this basically
kinematic approach, we limit ourselves to the observationally justifiable
assumptions of homogeneity and isotropy; i.e., to the assumption that the
universe has a RW metric. This cosmographic approach is historically the
original one to cosmology. We perform the analysis by expanding the scale
factor into a polynomial of order 5, which assumption can be further
generalised to any order. The present expansion rates h, q_0, r_0 etc. are
evaluated by computing the marginal likelihoods for these parameters. These
values are relevant, since any cosmological solution would ultimately need to
explain them.


title: On the Planet and the Disk of CoKuTau/4

abstract:
  Spitzer observations of the young star CoKuTau/4 reveal a disk with a 10 AU
hole that is most likely caused by a newly formed planet. Assuming that the
planet opened a gap in the viscous disk, we estimate that the planet mass is
greater than 0.1 Jupiter masses. This estimate depends on a lower limit to the
disk viscosity derived from the time scale needed to accrete the inner disk,
creating the now detectable hole. The planet migration time scale must at least
modestly exceed the time for the spectrally inferred hole to clear. The
proximity of the planet to the disk edge implied by our limits suggests that
the latter is perturbed by the nearby planet and may exhibit a spiral pattern
rotating with the planet. This pattern might be resolved with current ground
based mid-infrared cameras and optical cameras on the Hubble Space Telescope.
The required sub-Myr planet formation may challenge core accretion formation
models. However, we find that only if the planet mass is larger than about 10
Jupiter masses, allowing for a high enough surface density without inducing
migration, would formation by direct gravitational instability be possible.


title: Hydrocarbon Dust Absorption in Seyfert Galaxies and ULIRGs

abstract:
  We present new spectroscopic observations of the 3.4 micron absorption
feature in the Seyfert galaxies, NGC1068 and NGC7674, and the ultraluminous
infrared galaxy, IRAS08572+3915. A signature of C-H bonds in aliphatic
hydrocarbons, the 3.4 micron feature indicates the presence of organic material
in Galactic and extragalactic dust. Here we compare the 3.4 micron feature in
all the galaxies in which it has been detected. In several cases, the
signal-to-noise ratio and spectral resolution permit a detailed examination of
the feature profile, something which has rarely been attempted in extragalactic
lines of sight. The 3.4 micron band in these galaxies closely resembles that
seen in the Galactic diffuse ISM and in newly-formed dust in a protoplanetary
nebula. The similarity implies a common carrier for the carbonaceous component
of dust, and one which is resistant to processing in the interstellar and/or
circumnuclear medium. We also examine the mid-IR spectrum of NGC1068, because
absorption bands in the 5-8 micron region further constrain the chemistry of
the 3.4 micron band carrier. While weak features like those present in the
mid-IR spectrum of diffuse dust towards the Galactic center would be
undetectable in NGC1068, the strong bands found in the spectra of many proposed
dust analog materials are clearly absent, eliminating certain candidates and
production mechanisms for the carrier. The absence of strong absorption
features at 5-8 microns is also consistent with the interpretation that the
similarity in the 3.4 micron feature in NGC1068 to that in Galactic lines of
sight reflects real chemical similarity in the carbonaceous dust.


title: Holographic Bound on Information in Inflationary Perturbations

abstract:
  The formation of frozen classical perturbations from vacuum quantum
fluctuations during inflation is described as a unitary quantum process with
apparent "decoherence" caused by the expanding spacetime. It is argued that the
maximum observable information content per comoving volume in classical modes
is subject to the covariant entropy bound at the time those modes decohere,
leading to a new quantitative bound on the information contained in frozen
field modes in phase space. This bound implies holographic correlations of
large-scale cosmological perturbations that may be observable.


title: Neutrino Emission and Mass Ejection in Quark Novae

abstract:
  We explore the role of neutrinos in a Quark Nova explosion. We study
production of neutrinos during this event, their propagation and their
interactions with the surrounding quark matter and neutron-rich envelope. We
address relevant physical issues such as the timescale for the initial core
collapse, the total energy emitted in neutrinos and their effect on the low
density matter surrounding the core. We find that it is feasible that the
neutrino burst can lead to significant mass ejection of the nuclear envelope.


title: A search for cyclotron resonance features with INTEGRAL

abstract:
  We present an INTEGRAL observation of the Cen-Crux region in order to search
the electron cyclotron resonance scattering features from the X-ray binary
pulsars. During the AO1 200ks observation, we clearly detected 4 bright X-ray
binaries, 1 Seyfert Galaxy, and 4 new sources in the field of view. Especially
from GX301-2, the cyclotron resonance feature is detected at about 37 keV, and
width of 3--4 keV. In addition, the depth of the resonance feature strongly
depends on the X-ray luminosity. This is the first detection of luminosity
dependence of the resonance depth. The cyclotron resonance feature is
marginally detected from 1E1145.1-6141. Cen X-3 was very dim during the
observation and poor statistics disable us to detect the resonance
features.These are first INTEGRAL results of searching for the cyclotron
resonance feature.


title: HI 21 cm Emission Line Study of Southern Galactic Supernova Remnants

abstract:
  We have searched for HI 21 cm line emission from shocked atomic gas
associated with southern supernova remnants (SNRs) using data from the Southern
Galactic Plane Survey. Among the 97 sources studied, we have detected 10 SNRs
with high-velocity HI emission confined to the SNR. The large velocity and the
spatial confinement suggest that the emission is likely from the gas
accelerated by the SN blast wave. We also detected 22 SNRs which show HI
emission significantly brighter than the surrounding regions over a wide
($>10$\kms) velocity interval. The association with these SNRs is less certain.
We present the parameters and maps of the excess emission in these SNRs. We
discuss in some detail the ten individual SNRs with associated high-velocity HI
emission.


title: Entropy of the intracluster medium at high redshift

abstract:
  Recent observations of entropy of intracluster medium (ICM) at high redshift
are not consistent with a redshift independent entropy floor. In order to
interpret these observations, we study models in which the entropy of ICM is
enhanced at the epoch of cluster formation (z_f), which then passively evolves
as a result of radiative cooling until the epoch of observation (z_o). We
confirm that a z-independent entropy floor is incompatible with the
observations. We find that models in which energy deposition into the ICM
increases with redshift (scaling approximately as $\sim M_cl^0.6 (1+z_f)^2.2$)
are consistent with observations of low and high redshift clusters. Possible
sources of such non-gravitational heating are briefly discussed.


title:
Optical studies of V4332 Sagittarii - detection of unusually strong KI
  and NaI lines in emission

abstract:
  We present optical observations of the enigmatic nova-like variable V4332
Sgr. The importance of this object should not be understated since it is
considered to be the possible prototype of a new class of eruptive variables.
These objects have been the subject of considerable studies at present
primarily because of the spectacular eruption of V838 Mon - another member of
this class - recently in 2002. The cause of the outburst in such objects is not
well understood. Our recent work has shown striking changes in the near-IR
spectrum of V4332 Sgr since its 1994 outburst. The optical spectrum presented
here confirms that V4332 Sgr is indeed an unusual and extremely interesting
object. This spectrum, the first to be taken after a hiatus of nearly 10 years
after the outburst, shows several lines in emission but is dominated by
exceptionally strong emission in the resonance doublet of KI at 7665 and
7699{\AA} and to a slightly lesser strength in the unresolved NaI doublet at
5890 and 5896{\AA}. The KI lines are shown to be optically thick and
considerably broadened. We investigate the site of origin of the KI and NaI
emission. We discuss whether V4332 Sgr is related to L or T type dwarf based on
BVRI photometry.


title: A search for radioactive 26Al in the nova-like variable V4332 Sagittarii

abstract:
  We have searched for the important radioactive isotope 26Al in the nova-like
source V4332 Sgr. Recent results from gamma ray astronomy show that there is
pervasive emission of the 1.809 MeV gamma ray photon, arising from the decay of
26Al to 26Mg, from all over the galactic plane. Though the sites from where
this emission originates are not clearly established, novae are believed to be
an important contributing source. In this context, V4332 Sgr presented a rare
opportunity to observationally investigate whether novae or novae-like sources
synthesize 26Al and to what extent. Strong AlO bands in the near-IR have been
reported in this object recently. As molecular bands of different isotopic
compositions are readily resolved spectroscopically (e.g. 12CO and 13CO), it
was thought that the components of AlO associated with
  26Al and stable 27Al could be detected as separate bands. Our spectra
indicate that there is no strong presence of 26Al in V4332 Sgr. A reliable
upper limit of 0.10 for the 26Al/27Al ratio is determined which constitutes the
first observational constraint for this ratio in a potential 26Al producing
source. While V4332 Sgr is not a typical nova, its outburst amplitude and
light-curve behaviour bear close similarity to that of novae. Hence, although
the results from V4332 Sgr cannot be directly extended to novae in general, the
limit on the observed 26Al/27Al ratio could be a useful input in constraining
rather uncertain nucleosynthesis models for the production of 26Al in
novae/novae-like sources. By comparing the observed 26Al/27Al ratio in V4332
Sgr with that expected in classical novae it appears unlikely that the
progenitor of V4332 Sgr is an Oxygen-Neon-Magnesium white dwarf.


title: The build-up of the red-sequence in galaxy clusters since z~0.8

abstract:
  We study the rest-frame (U-V) color-magnitude relation in 4 clusters at
redshifts 0.7-0.8, drawn from the ESO Distant Cluster Survey. We confirm that
red-sequence galaxies in these clusters can be described as an old,
passively-evolving population and we demonstrate, by comparison with the Coma
cluster, that there has been significant evolution in the stellar mass
distribution of red-sequence galaxies since z~0.75. The EDisCS clusters exhibit
a deficiency of low luminosity passive red galaxies. Defining as `faint' all
galaxies in the passive evolution corrected range 0.4>~ L/L*>~0.1, the
luminous-to-faint ratio of red-sequence galaxies varies from 0.34+/-0.06 for
the Coma cluster to 0.81+/-0.18 for the high redshift clusters. These results
exclude a synchronous formation of all red-sequence galaxies and suggest that a
large fraction of the faint red galaxies in current clusters moved on to the
red-sequence relatively recently. Their star formation activity presumably came
to an end at z<~0.8.


title: Palatini formulation of L(R) gravity

abstract:
  We review the Palatini formulation of the higher-derivative gravity of the
$L(R)$ form and its applications in cosmology.


title:
Cluster AgeS Experiment. Catalog of Variable Stars in the Globular
  Cluster Omega Centauri

abstract:
  We present results of a photometric survey for variable stars in the field of
the globular cluster Omega Centauri. The observed region was centered roughly
on the cluster core and covered 644 arcmin^2. The cluster was monitored on 59
nights in 1999 and 2000. A total of 117 new variables were identified. Among
them there are 16 RR Lyr-type stars, 35 SX Phe variables and 26 eclipsing
binaries. A comprehensive catalog including all variable stars so far reported
from the cluster field is presented. We list basic photometric properties and
provide finding charts for a total of 392 objects. For 313 of them new BV light
curves were obtained. The presented sample includes several interesting
variables, such as SX Phe stars with extremely short periods of pulsation and
several candidates for pulsating K giants. Optical counterparts to 9 X-ray
sources detected by XMM and Chandra telescopes were identified: all of them are
likely to be foreground variables not related to the cluster.


title:
The nearest cool white dwarf (d~4pc), the coolest M-type subdwarf
  (sdM9.5), and other high proper motion discoveries

abstract:
  We report the discovery of seven high proper motion stars with proper motions
between about 0.7 and 2.2 arcsec/yr. They were detected in an archival search
using multi-epoch positions in the optical SuperCOSMOS Sky Surveys and in the
near-infrared sky surveys 2MASS and DENIS. The star with the largest proper
motion, is spectroscopically classified as a very nearby (d=8pc) M5.5 dwarf
with Galactic thin disk kinematics. A second star with about 2 arcsec/yr proper
motion, is still lacking spectroscopic confirmation but can be classified from
photometry as thick disk M3.5 dwarf. Three objects turn out to be cool subdwarf
members of the Galactic thick disk or halo, including the first sdM9.5 object,
which represents the currently coolest known M subdwarf, another ultra-cool
subdwarf, of spectral type sdM7.0 as well as an earlier type (sdM1.5) star. The
latter has an extremely large space velocity with clear halo kinematics. Two
objects show featureless spectra typical of cool white dwarfs. One of them is
probably a very nearby (d~4pc) thin disk object and may be the nearest isolated
white dwarf, the other one has thick disk kinematics.


title: Non-LTE line-formation for hydrogen revisited

abstract:
  We discuss aspects of non-LTE line formation for hydrogen in early-type
stars. We evaluate the effect of variations in the electron-impact excitation
cross sections in model atoms of differing complexity by comparison with
observation. While the Balmer lines are basically unaffected by the choice of
atomic data, the Paschen, Brackett and Pfund series members allow us to
discriminate between the different models. Non-LTE calculations based on the
widely-used approximation formulae of Mihalas, Heasley & Auer and of Johnson
fail to simultaneously reproduce the optical and IR spectra over the entire
parameter range. The use of data from ab-initio calculations up to principal
quantum number n<=7 largely solves the problem. We recommend a reference model
using the available data. This model is of general interest because of the
ubiquity of the hydrogen spectrum.


title: The solar hydrogen spectrum in non-LTE

abstract:
  We investigate the synthesis of the Balmer and Paschen lines of the quiet
Sun, using both classical semi-empirical and theoretical model atmospheres,
modern line broadening theory and non-LTE line-formation. The computations
alleviate long-standing discrepancies between LTE predictions and the observed
lines. Theoretical and semi-empirical model atmospheres without a chromosphere
on the one hand and semi-empirical models with a chromosphere on the other
produce two physically disjoint solutions for the run of non-LTE level
populations, including HII, throughout the model stratification. The resulting
synthetic non-LTE line profiles are practically identical and reproduce the
observation in either case, despite large differences in the line-formation
depths, e.g., a chromospheric origin of the Halpha core (in concordance with
observation) versus a photospheric origin. The findings are of much broader
interest, assuming the Sun to be a prototype cool dwarf star. A consistent
account for chromospheres in cool star analyses is required, due to their
potential to change atmospheric structure via non-LTE effects on the ionization
balance of hydrogen and thus the free electron pool. The latter in turn affects
the main opacity source H-. This will in particular affect the atmospheres of
metal-poor and evolved stars, in which the contribution of hydrogen to the
electron pool becomes dominant.


title: Evolution of Young Brown Dwarf Disks in the Mid-Infrared

abstract:
  We have imaged two bona-fide brown dwarfs with TReCS/GEMINI-S and find
mid-infrared excess emission that can be explained by optically thick dust disk
models. In the case of the young ($\approx$2Myr) Cha H$\alpha$1 we measure
fluxes at 10.4$\mu$m and 12.3$\mu$m that are fully consistent with a standard
flared disk model and prominent silicate emission. For the $\approx$ 10Myr old
brown dwarf 2MASS1207-3932 located in the TW Hydrae association we find excess
emission at 8.7$\mu$m and 10.4$\mu$m with respect to its photosphere, and
confirm disk accretion as likely cause of its strong activity. Disks around
brown dwarfs likely last at least as long as their low-mass stellar
counterparts in the T-Tauri phase. Grain growth, dust settling, and evolution
of the geometry of brown dwarfs disks may appear on a timescale of 10Myr and
can be witnessed by observations in the mid-infrared.


title: Merging Processes and SZ Effect

abstract:
  Recent observations reveal detailed structures of mergers in galaxy clusters.
Moving cold fronts could be identified as remnants of subclusters. They are
believed to mark the late stage of a merging process. Dynamics, geometry and
extension of the subclusters can be very different: Spherically shaped bodies
with a radius of $\approx 20 kpc$ up to $\approx 400 kpc$ and Mach numbers
between $\mathcal{M}\approx 0.4$ and $\mathcal{M}\approx 1.5$ are observed. In
order to analyse the Sunyaev-Zeldovich (SZ) signal, we calculate the modified
pressure profile for an ongoing merger.


title: The Planetary Nebula System of M33

abstract:
  We report the results of a photometric and spectroscopic survey for planetary
nebulae (PNe) in the Local Group spiral galaxy M33. We use our sample of 152
PNe to derive an [O III] planetary nebula luminosity function (PNLF) distance
of (m-M)_0 = 24.86^+0.07-0.11 (0.94^+0.03-0.05 Mpc). Although this value is ~
15% larger than the galaxy's Cepheid distance, the discrepancy likely arises
from differing assumptions about the system's internal extinction. Our
photometry (which extends >3 mag down the PNLF), also reveals that the
faint-end of M33's PN luminosity function is non-monotonic, with an inflection
point ~2 mag below the PNLF cutoff. We argue that this feature is due to the
galaxy's large population of high core-mass planetaries, and that its amplitude
may eventually be useful as a diagnostic for studies of stellar populations.
  Fiber-coupled spectroscopy of 140 of the PN candidates confirms that M33's PN
population rotates along with the old disk, with a small asymmetric drift of \~
10km/s. Remarkably, the population's line-of-sight velocity dispersion varies
little over ~4 optical disk scale lengths, with sigma_{rad}~20km/s. We show
that this is due to a combination of factors, including a decline in the radial
component of the velocity ellipsoid at small galactocentric radii, and a
gradient in the ratio of the vertical to radial velocity dispersion. We use our
data to show that the mass scale length of M33's disk is ~2.3 times larger than
that of the system's IR luminosity and that the disk's V-band mass-to-light
ratio changes from M/L_V ~0.3 in the galaxy's inner regions to M/L_V ~2.0 at ~9
kpc. Models in which the dark matter is distributed in the plane of the galaxy
are excluded by our data. (abridged)


title:
New spectral classification technique for X-ray sources: quantile
  analysis

abstract:
  We present a new technique called "quantile analysis" to classify spectral
properties of X-ray sources with limited statistics. The quantile analysis is
superior to the conventional approaches such as X-ray hardness ratio or X-ray
color analysis to study relatively faint sources or to investigate a certain
phase or state of a source in detail, where poor statistics does not allow
spectral fitting using a model. Instead of working with predetermined energy
bands, we determine the energy values that divide the detected photons into
predetermined fractions of the total counts such as median (50%), tercile (33%
& 67%), and quartile (25% & 75%). We use these quantiles as an indicator of the
X-ray hardness or color of the source. We show that the median is an improved
substitute for the conventional X-ray hardness ratio. The median and other
quantiles form a phase space, similar to the conventional X-ray color-color
diagrams. The quantile-based phase space is more evenly sensitive over various
spectral shapes than the conventional color-color diagrams, and it is naturally
arranged to properly represent the statistical similarity of various spectral
shapes. We demonstrate the new technique in the 0.3-8 keV energy range using
Chandra ACIS-S detector response function and a typical aperture photometry
involving background subtraction. The technique can be applied in any energy
band, provided the energy distribution of photons can be obtained.


title:
The Structure of the Local Interstellar Medium. III. Temperature and
  Turbulence

abstract:
  We present 50 individual measurements of the gas temperature and turbulent
velocity in the local interstellar medium (LISM) within 100 pc. By comparing
the absorption line widths of many ions with different atomic masses, we can
satisfactorily discriminate between the two dominant broadening mechanisms,
thermal broadening, and macroscopic nonthermal, or turbulent, broadening. We
find that the successful use of this technique requires a measurement of a
light ion, such as DI, and an ion at least as heavy as MgII. However,
observations of more lines provides an important consistency check and can also
improve the precision and accuracy of the measurement. The weighted mean gas
temperature in the LISM warm clouds is 6680 K and the dispersion about the mean
is 1490 K. The weighted mean turbulent velocity is 2.24 km s^-1 and the
dispersion about the mean is 1.03 km s^-1. The ratio of the mean thermal
pressure to the mean turbulent pressure is P_T/P_xi ~ 26. Turbulent pressure in
LISM clouds cannot explain the difference in the apparent pressure imbalance
between warm LISM clouds and the surrounding hot gas of the Local Bubble.
Pressure equilibrium among the warm clouds may be the source of a moderately
negative correlation between temperature and turbulent velocity in these
clouds. However, significant variations in temperature and turbulent velocity
are observed. The turbulent motions in the warm partially ionized clouds of the
LISM are definitely subsonic, and the weighted mean turbulent Mach number for
clouds in the LISM is 0.19 with a dispersion of 0.11. (Abridged)


title:
The Orbital Period of the Ultracompact Low-Mass X-Ray Binary 4U
  1543--624

abstract:
  We report the discovery of the orbital period of the ultracompact low-mass
X-ray binary (LMXB) 4U 1543-624 using time-resolved optical photometry taken
with the 6.5-m Clay (Magellan II) telescope in Chile. The light curve in the
Sloan r' band clearly shows a periodic, sinusoidal modulation at 18.2+-0.1 min
with a fractional semiamplitude of 8%, which we identify as the binary period.
This is the second shortest orbital period among all the known LMXBs, and it
verifies the earlier suggestion of 4U 1543-624 as an ultracompact binary based
on X-ray spectroscopic properties. The sinusoidal shape of the optical
modulation suggests that it arises from X-ray heating of the mass donor in a
relatively low-inclination binary, although it could also be a superhump
oscillation in which case the orbital period is slightly shorter. If the donor
is a C-O white dwarf as previously suggested, its likely mass and radius are
around 0.03 M_sun and 0.03 R_sun, respectively. For conservative mass transfer
onto a neutron star and driven by gravitational radiation, this implies an
X-ray luminosity of 6.5X10^36 erg/s and a source distance of 7 kpc. We also
discuss optical photometry of another LMXB, the candidate ultracompact binary
4U 1822-000. We detected significant optical variability on a time scale of
about 90 min, but it is not yet clear whether this was due to a periodic
modulation.


title: Accretion disks around black holes with account of magnetic fields

abstract:
  Accretion disks are observed in young stars, cataclysmic variables, binary
X-ray sources et al. Accretion disk theory was first developed as a theory with
the local heat balance, where the whole energy produced by a viscous heating
was emitted to the sides of the disk. Important part of this theory was the
phenomenological treatment of the turbulent viscosity, known the `` alpha''
prescription, where the $(r \phi)$ component of the stress tensor was connected
with the pressure as $\alpha P$. Sources of turbulence in the accretion disk
are discussed, including hydrodynamic turbulence, convection and magnetic field
role. Optically thin solution and advective disks are considered. Related
problems of mass ejection from magnetized accretion disks and jet formation are
discussed.


title: Gravitational Wave Background of Neutron Star-White Dwarf Binaries

abstract:
  We discuss the stochastic background of gravitational waves from ultra
compact neutron star-white dwarf (NS-WD) binaries at cosmological distances.
Under the assumption that accreting neutron stars and donor white dwarf stars
form most of the low mass X-ray binaries (LMXBs), our calculation makes use of
recent results related to the luminosity function determined from X-ray
observations. Even after accounting for detached NS-WD binaries not captured in
X-ray data, the NS-WD background is at least an order of magnitude below that
due to extragalactic white dwarf-white dwarf binaries and below the
detectability level of the Laser Interferometer Space Antenna (LISA) at
frequencies between 10^-5 Hz and 10^-1 Hz. While the extragalactic background
is unlikely to be detected, we suggest that around one to ten galactic NS-WD
binaries may be resolved with LISA such that their positions are determined to
an accuracy of several degrees on the sky.


title:
Dealing with systematics in cosmic shear studies: new results from the
  VIRMOS-Descart Survey

abstract:
  We present a reanalysis of the VIRMOS-Descart weak lensing data, with a
particular focus on different corrections for the variation of the point spread
function anisotropy (PSF) across the CCDs. We show that the small scale
systematics can be minimised, and eventually suppressed, using the B mode
(curled shear component)measured in the corrected stars and galaxies. Updated
cosmological constraints are obtained, free of systematics caused by PSF
anisotropy. To facilitate general use of our results, we provide the two-points
statistics data points with their covariance matrices up to a scale of one
degree. For the normalisation of the mass power spectrum we obtain
sigma_8=(0.83\pm 0.07)(Omega_M/0.3)^(-0.49). The shape parameter Gamma was
marginalised over Gamma=[0.1,0.3] and the mean source redshift z_s over
[0.8,1.0]. The latter is consistent with recent photometric redshifts obtained
for the VIRMOS data and the preliminary spectroscopic redshifts from the
VIRMOS-VVDS survey. The quoted 68% contour level includes all identified
sources of error. We discuss the possible sources of residual contamination in
this result: the effect of the non-linear mass power spectrum and remaining
issues concerning the PSF correction. Our result is compared with the first
release of the Wilkinson Microwave Anisotropy Probe data. It is found that Cold
Dark Matter models with a power law primordial power spectrum and high matter
density Omega_M > 0.5 are excluded at 3-sigma.


title: Can giant planets form by direct gravitational instability?

abstract:
  Gravitational instability has been invoked as a possible mechanism of giant
planet formation in protoplanetary disks. Here we critically revise its
viability by noting that for the direct production of giant planets it is not
enough for protoplanetary disks to be gravitationally unstable. They must also
be able to cool efficiently (on a timescale comparable to the local disk
orbital period) to allow the formation of bound clumps by fragmentation.
Combination of dynamical and thermal constraints puts very stringent lower
limits on the surface density and temperature of disks capable of fragmenting
into self-gravitating objects: for the gravitational instability to form giant
planets at 10 AU gas temperature at this location must exceed 10^3 K for a
minimum disk mass of 0.7 M_Sun and minimum disk luminosity of 40 L_Sun.
Although these requirements relax in more distant parts of the disk, masses of
bound objects formed as a result of instability even at 100 AU are too large
(\sim 10 M_Jupiter) to explain characteristics of known extrasolar giant
planets. Such protoplanetary disks (and planets formed in them) have very
unusual observational properties and this severely constrains the possibility
of giant planet formation by direct gravitational instability.


title: A Mode Fitting Methodology Optimized for Very Long Time Series

abstract:
  I describe and present the results of a newly developed fitting methodology
optimized for very long time series. The development of this new methodology
was motivated by the fact that we now have more than half a decade of nearly
uninterrupted observations by GONG and MDI, with fill factors as high as 89.8%
and 82.2% respectively. It was recently prompted by the availability of a
2088-day-long time series of spherical harmonic coefficients produced by the
MDI team.
  The fitting procedure uses an optimal sine-multi-taper spectral estimator --
whith the number of tapers based on the mode linewidth, the complete leakage
matrix (i.e., horizontal as well as vertical components), and an asymmetric
mode profile to fit simultaneously all the azimuthal orders with individually
parametrized profiles.
  This method was applied to 2088-day-long time series of MDI and GONG
observations, as well as 728-day-long subsets, and for spherical harmonic
degrees between 1 and 25. The values resulting from these fits are
inter-compared (MDI versus GONG) and compared to equivalent estimates from the
MDI team and the GONG project. I also compare the results from fitting the
728-day-long subsets to the result of the 2088-day-long time series. This
comparison shows the well known change of frequencies with solar activity --
and how it scales with a nearly constant pattern in frequency and m/l. This
comparison also shows some changes in the mode linewidth and the constancy of
the mode asymmetry.


title: Oscillation frequencies and mode lifetimes in alpha Centauri A

abstract:
  We analyse our recently-published velocity measurements of alpha Cen A
(Butler et al. 2004). After adjusting the weights on a night-by-night basis in
order to optimize the window function to minimize sidelobes, we extract 42
oscillation frequencies with l=0 to 3 and measure the large and small frequency
separations. We give fitted relations to these frequencies that can be compared
with theoretical models and conclude that the observed scatter about these fits
is due to the finite lifetimes of the oscillation modes. We estimate the mode
lifetimes to be 1-2 d, substantially shorter than in the Sun.


title: Resolution and accuracy of resonances in R-matrix cross sections

abstract:
  We investigate the effect of resonances in photoionization and recombination
cross sections computed using the R-matrix method. Photoionization and
recombination rates derived from high-resolution cross sections for oxygen ions
are compared with earlier works with less resolution and accuracy, such as in
the widely used Opacity Project data. We find significant differences in
photoionization rates for O II metastable states, averaged over Planck
functions corresponding to ionizing radiation fields, with respect to the
intrinsic accuracy of the calculations and improved resolution. Furthermore,
for highly charged ions other physical effects are also important.
Recombination rate coefficients, averaged over a Maxwellian distribution, are
extremely sensitive to the position and resolution of near-threshold
resonances, and radiation damping, in (e + O VII) --> O VI + hnu. Surprisingly
however, the effect on the monochromatic and the mean Rosseland and Planck
bound-free opacities is relatively small, but may be potentially significant.


title:
The exotic $H_3^{2+}$ ion in a strong magnetic field. Linear
  configuration

abstract:
  An accurate study of the lowest $1\sigma_g$ and the low-lying excited
$1\sigma_u$, $1\pi_{u,g}$, $1\delta_{g,u}$ electronic states of the exotic
molecular ion $H_3^{2+}$ in linear configuration parallel to a magnetic field
is carried out. The magnetic field ranges from $10^{10}$ G up to $4.414 \times
10^{13}$ G where non-relativistic considerations are justified. The variational
method is exploited and the {\it same} trial function is used for different
magnetic fields. It is shown that the states of positive $z$-parity $1\sigma_g,
1\pi_u, 1\delta_{g}$ are bound states of the $H_3^{2+}$ exotic ion for all
magnetic fields studied. We also demonstrate that for magnetic fields $B\gtrsim
2.35\times 10^{12}$ G the potential energy surface well corresponding to the
$1\sigma_g$ state contains at least one longitudinal vibrational state. It is
also shown that the negative $z$-parity states $1\sigma_u, 1\pi_g,
1\delta_{u}$, are purely repulsive in the whole range of magnetic fields
studied, $B=10^{10}- 4.414 \times 10^{13}$ G.


title:
New measurement on photon yields from air and the application to the
  energy estimation of primary cosmic rays

abstract:
  The air fluorescence technique is used to detect ultra-high energy cosmic
rays (UHECR), and to estimate their energy. Of fundamental importance is the
photon yield due to excitation by electrons, in air of various densities and
temperatures. After our previous report, the experiment has been continued
using a Sr90 $\beta$ source to study the pressure dependence of photon yields
for radiation in nitrogen and dry air. The photon yields in 15 wave bands
between 300 nm and 430 nm have been determined. The total photon yield between
300 nm and 406 nm (used in most experiments) in air excited by a 0.85 MeV
electron is 3.81+-0.13 (+-13 % systematics) photons per meter at 1013 hPa and
20 $^{\circ}$C. The air density and temperature dependencies of 15 wave bands
are given for application to UHECR observations.


title:
Cluster formation versus star formation rates around six regions in the
  LMC

abstract:
  The stellar population and star clusters around six regions in the Large
Magellanic Cloud (LMC) are studied to understand the correlation between star
formation and cluster formation rates. We used the stellar database of the OGLE
II LMC survey and the star cluster catalogues. The observed distribution of
stellar density on the colour-magnitude diagrams (CMDs) were compared with the
synthetic ones generated from the stellar evolutionary models. By minimising
the reduced chi-square values, the star formation history of the regions were
obtained in terms of the star formation rates (SFRs). All the regions were
found to show large SFRs between the ages 500 Myr - 2 Gyr with lower values for
younger and older ages. The correlated peak in the cluster and SFRs is found
for ages $sim$ 1 Gyr, and for ages less than 100 Myr. Five out of six regions
show significant cluster formation in the 100 - 300 Myr, while the SFRs were
found to be very low. This indicates anti-correlation between star and cluster
formation rates for the 100 - 300 Myr age range. A possible reason may be that
the stars are predominantly formed in clusters, whether bound or unbound, as a
result of star formation during the above age range. The enhanced cluster
formation rate at 100 - 300 Myr age range could be correlated with the
encounter of LMC with the Small Magellanic Cloud, while the enhanced star and
cluster formation at $\sim$ 1 Gyr does not correspond to any interaction. This
could indicate that the star formation induced by interaction is biased towards
group or cluster formation of stars.


title: Cosmological dynamics of D-cceleration

abstract:
  We study the cosmological dynamics of an effective theory for a strongly
coupled scalar field in the moduli space of $\mathcal{N}=4$ supersymmetric
Yang-Mills theory recently proposed by Silverstein and Tong, called
"D-cceleration". We discuss various Energy Conditions in this theory. Then we
prove the inflationary attractor property using the Hamilton-Jacobi method and
study the phase portrait as well as the cosmological evolution of the scalar
field.


title: Running of the Spectral Index in Noncommutative Inflation

abstract:
  We study the cosmological implications of the space-space noncommutative
inflation and present formulae for the spectral index and its running. Our
results show that deviations from the spectral index and its running depend on
the space-space noncommutativity length scale. We conclude that in the
slow-roll regime of a typical inflationary scenario, space-space
noncommutativity has negligible effects on both the spectral index and its
running. Two classes of examples have been studied and comparisons made with
the standard slow-roll formulae. The results show that the correction terms to
the commutative case are positive for the spectral index and negative for the
running of the spectral index. Nevertheless the spectral index in
noncommutative spaces is less than one owing to the very small values of the
correction terms.


title:
RXJ0256.5+0006: a merging cluster of galaxies at z=0.36 observed with
  XMM-Newton

abstract:
  (abridged) We present a study based on XMM data of RX J0256.5+0006, a medium
distant (z=0.36) galaxy cluster found in the Bright SHARC catalog. The
intracluster medium shows a bimodal structure: one main cluster component and a
substructure in the west. Despite the indication of interaction we do not find
any sign of temperature gradients. Due to the non-symmetric form of the main
cluster we extract surface brightness profiles in different sectors around its
centre. We see large variations between the profiles, which we quantify by
beta-model fitting. The corresponding r_c's vary between 0.1-0.5Mpc and the
beta's between 0.5-1.2. The variations of the beta-model parameters indicate
that the main cluster is not entirely relaxed. This hypothesis is strengthened
by the fact that the cluster is over-luminous with respect to the (z-evolving)
L_x-T relation found for nearby clusters. Comparing our profiles to the
reference emission measure profile of Arnaud et al., we find that only the
profile extracted north-east (NE) of the main cluster centre is similar to this
reference profile. This indicates that only the NE profile is representative
for the relaxed part of this cluster component. Using this profile and the
spectroscopically fitted temperature of T=4.9^+0.5_-0.4keV we find M_500~4
10^14 solar masses. This value is in agreement with the value obtained using
the z-evolving M_500-T relation from the HIFLUGCS sample. For the gas mass
fraction we find f_g~18-20% which is in good agreement with other work. We also
develop a simple on-axis merger model for the cluster. Together with a simple
ram pressure model we find that the most likely physical distance of the
subcluster to the main cluster lies between 0.6<d<1.0Mpc. We find for the ratio
of subcluster to main cluster mass values between 20-30%.


title: Regular particle acceleration in relativistic jets

abstract:
  Exact solution is obtained for electromagnetic field around a conducting
cylinder of infinite length and finite radius, with a periodical axial current,
when the wave length is much larger than the radius of the cylinder. The
solution describes simultaneously the fields in the near zone close to the
cylinder, and transition to the wave zone. Proper long-wave oscillations of
such cylinder are studied. The electromagnetic energy flux from the cylinder is
calculated. These solutions could be applied for description of the
electromagnetic field around relativistic jets from active galactic nuclei and
quasars and particle acceleration inside jets.


title: Spectral line and continuum radiation propagation in a clumpy medium

abstract:
  We discuss the propagation of spectral line and continuum radiation in a
clumpy medium and give general expressions for the observed absorption or
emission from a cloud population. We show that the affect of the medium
clumpiness can usually be characterised by a single number multiplying the mean
column opacity. Our result provides a simpler proof and generalisation of the
result of Martin et al (1984). The formalism provides a simple way to
understand the effects of clumping on molecular line profiles and ratios, for
example how clumping effects the interpretation of 13CO(1-0) to 12CO(1-0) line
ratios. It can also be used as a propagation operator in physical models of
clumpy media where the incident radiation effects the spectral line emissivity.
We are working to extend the formalism to the propagation of masers in a clumpy
medium, but in this case there are special difficulties because formal
expectation values are not characteristic of observations because they are
biased by rare events.


title: Observing Mkn 421 with XMM--Newton: the EPIC--PN point of view

abstract:
  We present three observations (four exposures) of Mkn 421 performed by
XMM--Newton in the Autumn of 2002, concentrating on the EPIC--PN camera data.
The X-ray spectra were soft and steepening toward high energies. The source was
highly variable and the hardness ratio plots displayed a clear
harder--when--stronger correlation. During two complete flares the source
showed strong spectral evolution: a hardness ratio and a time resolved spectral
analysis revealed both a clockwise and a counterclockwise rotating loop
patterns, suggesting the presence of temporal lags between different energy
bands variations. We confirmed this result and estimated the delay amounts with
a cross--correlation analysis performed on the single flares, discussing also
variability patterns that could reproduce the asymmetry seen in the
cross-correlation function. We verified our findings reproducing the two flares
with analytical models. We obtained consistent results: during one flare, Mkn
421 displayed soft lags, while in the other case it showed hard lags. In both
cases, the entity of the delays increases with the energy difference between
the compared light curves. Finally, we discussed the presence and the frequency
dependence of the temporal lags as an effect of particle acceleration, cooling
and escape timescales, showing that our data are consistent with this picture.


title: Photometric Redshift of X-Ray Sources in the Chandra Deep Field South

abstract:
  Based on the photometry of 10 near-UV, optical, and near-infrared bands of
the Chandra Deep Field South, we estimate the photometric redshifts for 342
X-ray sources, which constitute ~99% of all the detected X-ray sources in the
field. The models of spectral energy distribution are based on galaxies and a
combination of power-law continuum and emission lines. Color information is
useful for source classifications: Type-I AGN show non-thermal spectral
features that are distinctive from galaxies and Type-II AGN. The hardness ratio
in X-ray and the X-ray-to-optical flux ratio are also useful discriminators.
Using rudimentary color separation techniques, we are able to further refine
our photometric redshift estimations. Among these sources, 137 have reliable
spectroscopic redshifts, which we use to verify the accuracy of photometric
redshifts and to modify the model inputs. The average relative dispersion in
redshift distribution is ~8%, among the most accurate for photometric surveys.
The high reliability of our results is attributable to the high quality and
broad coverage of data as well as the applications of several independent
methods and a careful evaluation of every source. We apply our redshift
estimations to study the effect of redshift on broadband colors and to study
the redshift distribution of AGN. Our results show that both the hardness ratio
and U-K color decline with redshift, which may be the result of a K-correction.
The number of Type-II AGN declines significantly at z>2 and that of galaxies
declines at z>1. However, the distribution of Type-I AGN exhibits less redshift
dependence. As well, we observe a significant peak in the redshift distribution
at z=0.6. We demonstrate that our photometric redshift estimation produces a
reliable database for the study of X-ray luminosity of galaxies and AGN.


title: GRS 1915+105 and the Disc-Jet Coupling in Accreting Black Hole Systems

abstract:
  GRS 1915+105 - the first stellar-scale, highly relativistic jet source
identified - is a key system for our understanding of the disc-jet coupling in
accreting black hole systems. Comprehending the coupling between inflow and
outflow in this source is important not only for X-ray binary systems but has a
broader relevance for studies of active galactic nuclei and gamma-ray bursts.
In this paper, we present a detailed review of the observational properties of
the system, as established in the decade since its discovery. We attempt to
place it in context by a detailed comparison with other sources, and construct
a simple model for the disc-jet coupling, which may be more widely applicable
to accreting black hole systems.


title: Continuous star formation in IZw18

abstract:
  We study the dynamical and chemical evolution of a galaxy similar to IZw18
under the assumption of a continuous star formation during bursts. We adopt a
2-D hydrocode coupled with detailed chemical yields originating from SNeII,
SNeIa and from single intermediate-mass stars. Different nucleosynthetic yields
and different IMF slopes are tested. In most of the explored cases, a galactic
wind develops, mostly carrying out of the galaxy the metal-enriched gas
produced by the burst itself. The chemical species with the largest escape
probabilities are Fe and N. Consequently, we predict that the [$\alpha$/Fe] and
[$\alpha$/N] ratios outside the galaxy are lower than inside. In order to
reproduce the chemical composition of IZw18, the best choice seems to be the
adoption of the yields of Meynet & Maeder (2002) which take into account
stellar rotation, although these authors do not follow the whole evolution of
all the stars. Models with a flat IMF (x=0.5) seem to be able to better
reproduce the chemical properties of IZw18, but they inject in the gas a much
larger amount of energy and the resulting galactic wind is very strong, at
variance with observations. We also predict the evolution of the abundances in
the \hi medium and compare them with recent {\sl FUSE} observations.


title:
Very Luminous Carbon Stars in the Outer Disk of the Triangulum Spiral
  Galaxy

abstract:
  Stars with masses in the range from about 1.3 to 3.5 Mo pass through an
evolutionary stage where they become carbon stars. In this stage, which lasts a
few Myr, these stars are extremely luminous pulsating giants. They are so
luminous in the near-infrared that just a few of them can double the integrated
luminosity of intermediate-age (0.6 to 2 Gyr) Magellanic Cloud clusters at 2.2
microns. Astronomers routinely use such near-infrared observations to minimize
the effects of dust extinction, but it is precisely in this band that carbon
stars can contribute hugely. The actual contribution of carbon stars to the
outer disk light of evolving spiral galaxies has not previously been
morphologically investigated. Here we report new and very deep near-IR images
of the Triangulum spiral galaxy M33=NGC 598, delineating spectacular arcs of
carbon stars in its outer regions. It is these arcs which dominate the
near-infrared m=2 Fourier spectra of M33. We present near-infrared photometry
with the Hale 5-m reflector, and propose that the arcs are the signature of
accretion of low metallicity gas in the outer disk of M33.


title: Intermittent nulls in PSR B0818-13, and the subpulse-drift alias mode

abstract:
  We show that all long nulls in PSR B0818-13 are trains of rapidly alternating
nulls and pulses (each shorter than one pulse period). Sometimes only the nulls
coincide with our pulse window, resulting in one of the apparently long nulls
seen occasionally. We show these are seen as often as expected if during such a
train the probability for nulls is 1.2 times less than for pulses.
  During nulls, the subpulse drift-speed appears to increase. We assume that
the carousel of sparks that possibly underlies the subpulses actually slows
down, as it does in similar pulsars like PSR B0809+74, and conclude that the
subpulse-drift in this pulsar must be aliased. The carousel must then rotate in
30 seconds or less, making it the fastest found to date.


title: MOND predictions of "halo" phenomenology in disc galaxies

abstract:
  We examine two corollaries of MOND pertaining to the properties of the
equivalent dark-matter halo. MOND predicts for pure exponential discs a tight
relation involving the halo and disc scale lengths and the mean acceleration in
the disc, which we find to test favorably against the Verheijen sample of Ursa
Major galaxies. A correlation between halo and disc length scales is also
apparent when the "maximum disc" contribution is assumed, but we demonstrate
that this follows from the more general MOND prediction. The second MOND
prediction involves the existence of a maximum halo acceleration, which also
tests favorably against the Ursa Major sample for different assumptions on the
disc contribution.


title: Bounds on Isocurvature Perturbations from CMB and LSS

abstract:
  Using both cosmic microwave background and large scale structure data, we put
stringent bounds on the possible cold dark matter, baryon and neutrino
isocurvature contributions to primordial fluctuations in the Universe.
Neglecting the possible effects of spatial curvature, tensor perturbations and
reionization, we perform a Bayesian likelihood analysis with nine free
parameters, and find that the relative amplitude of the isocurvature component
cannot be larger than about a few percent for uncorrelated models. On the other
hand, for correlated adiabatic and isocurvature components, the ratio could be
slightly larger. However, the cross-correlation coefficient is strongly
constrained, and maximally correlated/anticorrelated models are disfavored.


title: X-ray Study of the Intermediate-Mass Young Stars Herbig Ae/Be Stars

abstract:
  We present the ASCA results of intermediate-mass pre-main-sequence stars
(PMSs), or Herbig Ae/Be stars (HAeBes). Among the 35 ASCA pointed-sources, we
detect 11 plausible X-ray counterparts. X-ray luminosities of the detected
sources in the 0.5-10 keV band are in the range of log LX ~30-32 ergs s-1,
which is systematically higher than those of low-mass PMSs. This fact suggests
that the contribution of a possible low-mass companion is not large. Most of
the bright sources show significant time variation, particularly, two HAeBes -
MWC 297 and TY CrA - exhibit flare-like events with long decay timescales
(e-folding time ~ 10-60 ksec). These flare shapes are similar to those of
low-mass PMSs. The X-ray spectra are successfully reproduced by an absorbed one
or two-temperature thin-thermal plasma model. The temperatures are in the range
of kT ~1-5 keV, which are significantly higher than those of main-sequence OB
stars (kT < 1 keV). These X-ray properties are not explained by wind driven
shocks, but are more likely due to magnetic activity. On the other hand, the
plasma temperature rises as absorption column density increases, or as HAeBes
ascend to earlier phases. The X-ray luminosity reduces after stellar age of a
few x10^6 years. X-ray activity may be related to stellar evolution. The age of
the activity decay is apparently near the termination of jet or outflow
activity. We thus hypothesize that magnetic activity originates from the
interaction of the large scale magnetic fields coupled to the circumstellar
disk. We also discuss differences in X-ray properties between HAeBes and
main-sequence OB stars.


title:
The influence of rotation in radiation driven wind from hot stars: New
  solutions and disk formation in Be stars

abstract:
  The theory of radiation driven wind including stellar rotation is
re-examined. After a suitable change of variables, a new equation for the mass
loss rate is derived analytically. The solution of this equation remains within
1% confidence when compared with numerical solutions. Also, a non-linear
equation for the position of the critical (singular) point is obtained. This
equation shows the existence of an additional critical point, besides the
standard m--CAK critical point. For a stellar rotation velocity larger than
aprox. 0.7 - 0.8 V_{breakup}, there exists only one critical point, located
away from the star's surface. Numerical solutions crossing through this new
critical point, are attained. In these cases, the wind has a very low terminal
velocity and therefore a higher density wind. Disk formation in Be stars is
discussed in the frame of this new line driven stellar wind solution.


title: The Detection and Nature of the Baryonic Dark Matter

abstract:
  Since the original baryonic dark matter detection from quasar microlensing
was first announced in 1996, substantial strides have been made in confirming
the rapid microlensing signature in the Q0957 system and in other gravitational
lens systems. The most rapid event recognized had a 1% amplitude and a 12-hour
duration.
  Interpretation of the rapid fluctuations has centered upon 3 offered
explanations; microlensing of fine quasar structure by a population of planet
mass astronomical bodies in the lens galaxy, orbiting bright structures in the
accretion disc of the supermassive black hole of the quasar, or dark clouds
swarming around the luminous quasar source. The observations, particularly the
equal positive and negative fluctuations, seem to strongly favor the
cosmological population of planetary mass objects in the lens galaxy.
  Of the several ideas advanced for the origin of such a population, the most
appealing seems to be their birth at the time of recombination 300,000 years
after the Big Bang.


title:
Dust penetrated arm classes: insight from rising and falling rotation
  curves

abstract:
  We present near-infrared K-band images of 15 galaxies. We have performed a
Fourier analysis on the spiral structure of these galaxies in order to
determine their pitch angles and dust-penetrated arm classes. We have also
obtained rotation curve data for these galaxies and calculated their shear
rates. We show that there is a correlation between pitch angle and shear rate
and conclude that the main determinant of pitch angle is the mass distribution
within the galaxy. This correlation provides a physical basis for the
dust-penetrated classification scheme of Block & Puerari (1999).


title: Revealing the Young Starburst in Haro 3 with Radio and Infrared Imaging

abstract:
  The Wolf-Rayet galaxy Haro 3 (Mrk 35, NGC 3353) was observed at the near-IR
and radio wavelengths as part of ongoing program to study the earliest stages
of starbursts. These observations confirm that the current episode of star
formation is dominated by a single region (region A). While there are knots of
recent (~10 Myr) star formation outside of region A, the sources of ionizing
radiation as observed in both radio and Br-gamma observations are almost
exclusively associated with region A. The derived ionizing flux implies a star
formation rate of ~0.6 solar masses per year localized within a radius of ~0.1
kpc. A comparison with observations from HST indicates that one or more of the
star clusters in region A are optically obscured. The star clusters in region A
have ages at least as young as ~5 Myr, and possibly as young as ~0.1 Myr. The
star cluster that appears to be the youngest also exhibits a near-IR excess in
its colors, possibly indicating natal dust in very close proximity to the
ionizing stars. The difference between optical- and radio-determined ionizing
fluxes as well as the near-IR colors indicate an average extinction value of
A_V ~2.5 in region A. The total stellar mass associated with the current
starburst in region A is inferred from both the near-IR and radio observations
to be ~10^6 solar masses. The other main stellar concentrations observed in the
near-IR (Regions B1 and B2) are somewhat older than region A, with ages ~8-10
Myr, and the near-IR observations indicate they have stellar masses of ~8x10^4
and ~2x10^4 solar masses, respectively.


title: Quantifying Bar Strength: Morphology Meets Methodology

abstract:
  A set of objective bar-classification methods have been applied to the Ohio
State Bright Spiral Galaxy Survey (Eskridge et al. 2002). Bivariate comparisons
between methods show that all methods agree in a statistical sense. Thus the
distribution of bar strengths in a sample of galaxies can be robustly
determined. There are very substantial outliers in all bivariate comparisons.
Examination of the outliers reveals that the scatter in the bivariate
comparisons correlates with galaxy morphology. Thus multiple measures of bar
strength provide a means of studying the range of physical properties of galaxy
bars in an objective statistical sense.


title:
Observing Conditions at Mt.Graham: VATT UBVR Sky Surface Brightness and
  Seeing Measurements from 1999 through 2003

abstract:
  We present measurements of sky surface brightness and seeing on Mt.Graham
obtained at the Vatican Advanced Technology Telescope (VATT) during 16
observing runs between April 1999 and December 2003. We show that the sky
surface brightness is significantly darker during photometric conditions, and
can be highly variable over the course of a single observing run as well as
from one run to the next, regardless of photometricity. In our photometric
observations we find an average low-airmass (sec z < 1.2) sky surface
brightness of 22.00, 22.53, 21.49, and 20.88 mag arcsec^-2 in U, B, V, and R,
respectively. The darkest run (02/00 in U and 02/01 in BVR) had an average sky
surface brightness of 22.38, 22.86, 21.72, and 21.19 mag arcsec^-2 in U, B, V,
and R, respectively. With these results we show that under the best conditions,
Mt. Graham can compete with the darkest sites in Hawaii and Chile, thanks in
part to the strict dark-sky ordinances in place in Tucson and Safford. We
expect the sky over Mt. Graham to be even darker than our 1999--2003 results
during solar minimum (2006--2007). We find a significant improvement of about
0.45 arcsec in our measured stellar FWHM after improvements to the telescope
were made in Summer and Fall 2001. Stellar FWHM values are highly variable,
with median R-band focus FWHM values in each observing run ranging from 0.97
arcsec to 2.15 arcsec. Significantly sub-arcsecond seeing was occasionally
achieved with values as low as 0.65 arcsec FWHM in R. There may possibly still
be a significant telescope contribution to the seeing at the VATT, but nearby
trees as high as the dome are currently the dominant factor.


title: A Low CMB Quadrupole from Dark Energy Isocurvature Perturbations

abstract:
  We explicate the origin of the temperature quadrupole in the adiabatic dark
energy model and explore the mechanism by which scale invariant isocurvature
dark energy perturbations can lead to its sharp suppression. The model requires
anticorrelated curvature and isocurvature fluctuations and is favored by the
WMAP data at about the 95% confidence level in a flat scale invariant model. In
an inflationary context, the anticorrelation may be established if the
curvature fluctuations originate from a variable decay rate of the inflaton;
such models however tend to overpredict gravitational waves. This isocurvature
model can in the future be distinguished from alternatives involving a
reduction in large scale power or modifications to the sound speed of the dark
energy through the polarization and its cross correlation with the temperature.
The isocurvature model retains the same polarization fluctuations as its
adiabatic counterpart but reduces the correlated temperature fluctuations. We
present a pedagogical discussion of dark energy fluctuations in a quintessence
and k-essence context in the Appendix.


title:
The Zenith Angle Distribution of Fully Contained Events in
  SuperKamiokande and the Impact of Quasi Elastic Scattering on their Direction

abstract:
  Quasi Elastic Scattering (QEL) is the dominant mechanism for producing both
Fully Contained Events and Partially Contained Events in the SuperKamiokande
(SK) detector for atmospheric neutrinos in the range 0.1GeV to 10GeV. In the
analysis of SK events, it is assumed that the zenith angle of the incident
neutrino is the same as that of the detected charged lepton. In the present
paper, we derive the distribution function for the scattering angle of charged
leptons and derive the average scattering angles as well as their standard
deviation due to QEL. Thus, it is shown that the SK assumption for the
scattering angle of the charged lepton in QEL is not valid. Further, for a real
analysis of the experimental data, we should examine the correlations between
the zenith angle of the charged leptons and those of their incident neutrinos,
taking into account the effect of the azimuthal angle of the charged particle
over its zenith angle. We conclude that it is not possible to reliably assign
the zenith angle of the incident neutrino to that of the charged lepton, and so
the zenith angle distribution of charged leptons does not reflect that of the
incident neutrinos under the SK assumption. This result has clear implication
for attempts to detect neutrino oscillations from an analysis of Fully
Contained Events and Partially Contained Events in SuperKamiokande.


title: The stellar disk thickness of LSB galaxies

abstract:
  We present surface photometry results for a sample of eleven edge-on galaxies
observed with the 6m telescope at the Special Astrophysical Observatory
(Russia). The photometric scale length, scale height, and central surface
brightness of the stellar disks of our sample galaxies are estimated. We show
that four galaxies in our sample, which are visually referred as objects of the
lowest surface brightness class in the Revised Flat Galaxies Catalog, have bona
fide low surface brightness (LSB) disks. We find from the comparison of
photometric scales that the stellar disks of LSB galaxies are thinner than
those of high surface brightness (HSB) ones. There is a clear correlation
between the central surface brightness of the stellar disk and its vertical to
radial scale ratio. The masses of spherical subsystems (dark halo + bulge) and
the dark halo masses are obtained for the sample galaxies based on the
thickness of their stellar disks. The LSB galaxies tend to harbor more massive
spherical subsystems than the HSB objects, whereas no systematic difference in
the dark halo masses between LSB and HSB galaxies is found. At the same time,
the inferred mass-to-luminosity ratio for the LSB disks appears to be
systematically higher than for HSB disks.


title: Long time-scale variability in GRS1915+105

abstract:
  We present very high resolution hydrodynamical simulations of accretion discs
in black hole X-ray binaries accreting near the Eddington limit. The results
show that mass loss, irradiation and tidal interactions all have a profound
effect on the observed behaviour of long period X-ray transients. In
particular, the interplay of all of these effects in the outer regions of the
accretion disc is able to drive long time-scale (weeks to years) variability is
these objects, and is a possible origin for some of the extreme variability of
GRS1915+105.


title: Electron Abundance in Protostellar Cores

abstract:
  The determination of the fractional electron abundance, Xe, in protostellar
cores relies on observations of molecules, such as DCO+, H13CO+ and CO, and on
chemical models to interpret their abundance. Studies of protostellar cores
have revealed significant variations of Xe from core to core within a range
10^-8<Xe<10^-6. The physical origin of these large variations in Xe is not well
understood, unless unlikely variations in the cosmic ray ionization rate or ad
hoc values of metal depletion are assumed. In this work we explore other
potential causes of these variations in Xe, including core age, extinction and
density. We compute numerically the intensity of the radiation field within a
density distribution generated by supersonic turbulence. Taking into account
the lines of sight in all directions, the effective visual extinction in dense
regions is found to be always much lower than the extinction derived from the
column density along a fixed line of sight. Dense cores with volume and column
densities comparable to observed protostellar cores have relatively low
mass-averaged visual extinction, 2mag <= A_V <= 5mag, such that
photo-ionization can sometimes be as important as cosmic ray ionization.
Chemical models, including gas-grain chemistry and time dependent gas depletion
and desorption, are computed for values of visual extinction in the range 2mag
<= A_V <= 6mag, and for a hydrogen gas density of 10^4cm^-3$, typical of
protostellar cores. The models presented here can reproduce some of the
observed variations of ion abundance from core to core as the combined effect
of visual extinction and age variations. The range of electron abundances
predicted by the models is relatively insenstive to density over 10^4 to 10^6
cm^{-3}.


title: Stationary Population III accretion discs

abstract:
  We present stationary models of protostellar population III (Pop III, for
short) accretion discs, compare them to Pop I discs, and investigate the
influence of the different chemical compositions on the occurence of
gravitational, thermal and thermal-viscous instabilities in the discs. In
particular in the cooler regions, we find major differences between Pop III and
Pop I discs, both in the structure and stability behaviour. This is mainly due
to the absence of most molecules and dust in Pop III, which are very efficient
absorbers in Pop I discs.


title:
Relativistic Binary Merging Rate in the Universe:25 years of
  confrontation

abstract:
  Recently estimation of merger rate of double neutron stars from the
observations of PSR J0737-3039 by Burgay is discussed under real astrophysical
background.


title:
Deuterated hydrogen chemistry: Partition functions, Equilibrium
  constants and Transition intensities for the H3+ system

abstract:
  H3+ and the deuterated isotopomers are thought to play an important role in
interstellar chemistry. The partition functions of H3+, D2H+ and D3+ are
calculated to a temperature of 800 K by explicitly summing the ab initio
determined rotation-vibration energy levels of the respective species. These
partition functions are used to calculate the equilibrium constants for nine
important reactions in the interstellar medium involving H3+ and its deuterated
isotopomers. These equilibrium constants are compared to previously determined
experimental and theoretical values. The Einstein A coefficients for the
strongest dipole transitions are also calculated.


title: Could dark energy be measured in the lab?

abstract:
  The experimentally measured spectral density of current noise in Josephson
junctions provides direct evidence for the existence of zero-point
fluctuations. Assuming that the total vacuum energy associated with these
fluctuations cannot exceed the presently measured dark energy of the universe,
we predict an upper cutoff frequency of nu_c=(1.69 +- 0.05) x 10^12 Hz for the
measured frequency spectrum of zero-point fluctuations in the Josephson
junction. The largest frequencies that have been reached in the experiments are
of the same order of magnitude as nu_c and provide a lower bound on the dark
energy density of the universe. It is shown that suppressed zero-point
fluctuations above a given cutoff frequency can lead to 1/f noise. We propose
an experiment which may help to measure some of the properties of dark energy
in the lab.


title:
A new HI catalog of Low Surface Brightness galaxies out to z=0.1 -
  Tripling the number of massive LSB galaxies Known

abstract:
  Using both the Arecibo 305m and the Nancay decimetric 100-m class radio
telescopes, we have observed the HI line of 116 Low Surface Brightness (LSB)
galaxies from the Bothun et al. 1985 subset of LSB galaxies in the Uppsala
General Catalog. The observations had a detection rate of 70%, resulting in the
new determination of HI properties for 81 galaxies. Surprisingly, roughly half
of the detected objects (38) have M_HI >= 10^10 M_sol, placing them into the
category of massive LSB galaxies. As previously only ~18 of these `Malin 1
cousins' were known, our results have more than tripled the number of these
fascinating and enigmatic systems known.
  Combining our results with previous studies done on the Bothun et al. catalog
results in a well-defined catalog of HI properties of 526 LSB galaxies ranging
in redshift space from 0 <= z <= 0.1. With this catalog in hand, we have been
able to explore the parameter space occupied by LSB galaxies more completely
than has been previously possible. In agreement with previous studies, our
results show LSB galaxies with some of the most extreme properties of disk
galaxies, including M_HI/L_B ratios often exceeding 10 M_sol/L_sol,B.


title: Is the Giant Elliptical Galaxy NGC5018 a Post-Merger Remnant?

abstract:
  NGC5018, one of the weakest UV emitters among giant ellipticals (gE) observed
with IUE, appears to consist of an optical stellar population very similar to
that of the compact, dwarf elliptical M32, which is several magnitudes fainter
in luminosity than NGC5018 and whose stellar population is know to be ~3 Gyr
old. Here we show that the mid-UV spectra of these two galaxies are also very
similar down to an angular scale hundreds times smaller than the IUE large
aperture (as probed by HST/FOS UV spectra obtained through 0.86 arcsec
apertures). This implies a reasonably close match of the populations dominating
their mid-UV light (namely, their main-sequence turnoff stars). These data
indicate that NGC5018 has, in its inner regions, a rather uniform dominance of
a ~3 Gyr-old stellar population, probably a bit different in metallicity from
M32. Combined with the various structures that indicate that NGC5018 is the
result of a recent major merger, it appears that almost all of stars we see in
its center regions were formed about 3 Gyr ago, in that merger event. NGC5018
is likely the older brother of NGC7252, the canonical gE-in-formation merger.
As such, NGC5018 is perhaps the best galaxy which can tell us how a merger
works, after the fireworks subside, to form a gE galaxy today. For this reason
alone, the stellar populations in NGC5018 at all radii are worth studying in
detail.


title:
The progenitor of the 'born-again' core V605 Aql and the relation to its
  younger twin V4334 Sgr

abstract:
  We derived the properties of V605 Aql before the final helium flash pulse by
studying its surrounding PN A58. Photoionizing models of our spectral data
together with a new distance estimate and a closer look at the recombination
timescales lead to a consistent model. Comparing our findings with the only
hydrogen-poor twin, namely Sakurai's Object, we conclude that these born-again
objects have normal PNe core masses. We are able to prove V605 Aql indeed to
be, similar to V4332 Sgr, a very late thermal pulse object and to put
constraints for the evolutionary time scales for the transition back to the
AGB.


title: Crystalline Silicate Feature of the Vega-like star HD145263

abstract:
  We have observed the 8-13 $\mu$m spectrum (R$\sim$250) of the Vega-like star
candidate HD145263 using Subaru/COMICS. The spectrum of HD145263 shows the
broad trapezoidal silicate feature with the shoulders at 9.3 $\mu$m and 11.44
$\mu$m, indicating the presence of crystalline silicate grains. This detection
implies that crystalline silicate may also be commonly present around Vega-like
stars. The 11.44 $\mu$m feature is slightly shifted to a longer wavelength
compared to the usual 11.2-3 $\mu$m crystalline forsterite feature detected
toward Herbig Ae/Be stars and T Tauri stars. Although the peak shift due to the
effects of the grain size can not be ruled out, we suggest that Fe-bearing
crystalline olivine explains the observed peak wavelength fairly well.
Fe-bearing silicates are commonly found in meteorites and most interplanetary
dust particles, which originate from planetesimal-like asteroids. According to
studies of meteorites, Fe-bearing silicate must have been formed in asteroidal
planetesimals, supporting the scenario that dust grains around Vega-like stars
are of planetesimal origin, if the observed 11.44 $\mu$m peak is due to
Fe-bearing silicates.


title: Rotating Twin Stars and Signature of Quark-Hadron Phase Transition

abstract:
  The quark hadron phase transition in a rotating compact star has been
studied. The NLZ-model has been used for the hadronic sector and the MIT Bag
model has been used for the quark sector. It has been found that rotating twin
star (third family) solutions are obtained upto $\Omega \approx 4000 s^{-1}$.
Stars which are rotating faster than this limit do not show any twin star
solution. A backbending in moment of inertia is also observed in the
supermassive rest mass sequences. The braking index is found to diverge for a
star having pure quark core.


title:
The Giant Molecular Cloud associated with RCW 106 -- A 1.2 mm continuum
  mapping study

abstract:
  We have mapped the dust continuum emission from the molecular cloud covering
a region of 28pcx94pc associated with the well-known HII region RCW 106 at 1.2
mm using SIMBA on SEST. The observations, having an HPBW of 24" (0.4 pc),
reveal 95 clumps. Owing to the higher sensitivity to colder dust and higher
angular resolution the present observations identify new emission features and
also show that most of the IRAS sources in this region consist of multiple dust
emission peaks. The detected millimeter sources (MMS) include on one end the
exotic MMS5 (associated with IRAS 16183-4958, one of the brightest infrared
sources in our Galaxy) and the bright (and presumably cold) source MMS54, with
no IRAS or MSX associations on the other end. Around 10% of the sources are
associated with signposts of high mass star formation activity. Assuming a
uniform dust temperature of 20 K we estimate the total mass of the GMC
associated with RCW 106 to be ~10^5\msun. The constituent millimeter clumps
cover a range of masses and radii between 40 to 10^4 \msun and 0.3 to 1.9 pc.
Densities of the clumps range between (0.5-6) 10^4 cm^{-3}. We have decomposed
the continuum emission into gaussian and arbitrary shaped clumps using the two
independent structure analysis tools gaussclumps and clumpfind respectively.
The clump mass spectrum was found to have an index of 1.6+-0.3, independent of
the decomposition algorithm used. The index of the mass spectrum for the mass
and length scales covered here are consistent with results derived from large
scale CO observations.


title: No 'cut off' in the High Energy Cosmic Ray Energy Spectrum

abstract:
  It is often claimed that there should be a 'GZK cut-off" in the flux of
extragalactic cosmic rays, arising from interactions between the cosmic rays
and the cosmic micro-wave background photons (e.g. 1 and 2). Some experiments
(3 and 4) show particles of even higher energy than this value and this has led
to claims for exotic processes (e.g. 5 and 6).
  We contend that such claims are unnecessary - there is no predicted cut-off,
rather a continuation of the injection spectrum at reduced intensity. We have
combined the world's data and shown that the prediction for a rather flat
injection spectrum (exponent: 1.9 - 2.2) in the case of universal particle
injection provides a reasonable fit to the data. Conventional forms for the
particle attenuation in the intergalactic medium (e.g. 7 and 8) have been
assumed. Either protons or iron nuclei (or a mixture) will suffice.
  Attention is drawn to another aspect, too, that of the losses on the
infra-red radiation which may be intense near to strong sources and for sources
in galaxy clusters. The attendant magnetic fields near the sources leads to
significantly long diffusion times through the strong infra-red fields. Two
'case histories' are considered.


title: First phylogenetic analyses of galaxy evolution

abstract:
  The Hubble tuning fork diagram, based on morphology, has always been the
preferred scheme for classification of galaxies and is still the only one
originally built from historical/evolutionary relationships. At the opposite,
biologists have long taken into account the parenthood links of living entities
for classification purposes. Assuming branching evolution of galaxies as a
"descent with modification", we show that the concepts and tools of
phylogenetic systematics widely used in biology can be heuristically transposed
to the case of galaxies. This approach that we call "astrocladistics" has been
first applied to Dwarf Galaxies of the Local Group and provides the first
evolutionary galaxy tree. The cladogram is sufficiently solid to support the
existence of a hierarchical organization in the diversity of galaxies, making
it possible to track ancestral types of galaxies. We also find that morphology
is a summary of more fundamental properties. Astrocladistics applied to
cosmology simulated galaxies can, unsurprisingly, reconstruct the correct
"genealogy". It reveals evolutionary lineages, divergences from common
ancestors, character evolution behaviours and shows how mergers organize galaxy
diversity. Application to real normal galaxies is in progress. Astrocladistics
opens a new way to analyse galaxy evolution and a path towards a new
systematics of galaxies.


title:
The 2dF Galaxy Redshift Survey: Spherical Harmonics analysis of
  fluctuations in the final catalogue

abstract:
  We present the result of a decomposition of the 2dFGRS galaxy overdensity
field into an orthonormal basis of spherical harmonics and spherical Bessel
functions. Galaxies are expected to directly follow the bulk motion of the
density field on large scales, so the absolute amplitude of the observed
large-scale redshift-space distortions caused by this motion is expected to be
independent of galaxy properties. By splitting the overdensity field into
radial and angular components, we linearly model the observed distortion and
obtain the cosmological constraint Omega_m^{0.6} sigma_8=0.46+/-0.06. The
amplitude of the linear redshift-space distortions relative to the galaxy
overdensity field is dependent on galaxy properties and, for L_* galaxies at
redshift z=0, we measure beta(L_*,0)=0.58+/-0.08, and the amplitude of the
overdensity fluctuations b(L_*,0) sigma_8=0.79+/-0.03, marginalising over the
power spectrum shape parameters. Assuming a fixed power spectrum shape
consistent with the full Fourier analysis produces very similar parameter
constraints.


title: Inflation Induced Planck-Size Black Hole Remnants As Dark Matter

abstract:
  While there exist various candidates, the identification of dark matter
remains unresolved. Recently it was argued that the generalized uncertainty
principle (GUP) may prevent a black hole from evaporating completely, and as a
result there should exist a Planck-size BHR at the end of its evaporation. We
speculate that the stability of BHR may be further protected by supersymmetry
in the form of extremal black hole. If this is indeed the case and if a
sufficient amount of small black holes can be produced in the early universe,
then the resultant BHRs can be an interesting candidate for DM. We demonstrate
that this is the case in the hybrid inflation model. By assuming BHR as DM, our
notion imposes a constraint on the hybrid inflation potential. We show that
such a constraint is not fine-tuned. Possible observational signatures are
briefly discussed.


title:
IR Mergers and IR QSOs with Galactic Winds. II. NGC 5514, two
  Extra-nuclear Starburts/LINERs with a Supergiant Bubble in the Rupture Phase

abstract:
  A study of morphology, kinematics and ionization structure of the IR merger
NGC 5514, is presented. This study is based mainly on Integral 2D spectroscopy
obtained on 4.2 m William Herschel Telescope (La Palma, Spain) and data from
CASLEO (Argentina). Clear evidence of two extra-nuclear starbursts with young
outflows and LINER activity are reported. One of these outflow generate a
supergiant bubble, where the emission lines and kinematics maps show 4 extended
ejections. These results suggest that the bubble is in the rupture phase.


title:
Lens candidates in the Capodimonte Deep Field in the vicinity of the
  CSL1 object

abstract:
  CSL1 is a peculiar object discovered in the OACDF. Photometric and
spectroscopic investigation strongly suggest that it may be the first case of
gravitational lensing by cosmic string. In this paper we derive and discuss a
statistical excess of a gravitational lens candidates present in OACDF region
surrounding CSL1. This excess cannot be explained on the basis of conventional
gravitational lens statistic alone, but is compatible with the proposed cosmic
string scenario.


title: The HI Parkes Deep Zone of Avoidance Survey

abstract:
  The 64-m Parkes telescope, equipped with the 21-cm multibeam receiver, has
completed a sensitive survey (typically 6 mJy per beam rms) for HI galaxies in
the Zone of Avoidance accessible to the telescope, 196 < l < 52 deg, and |b| <
5 deg. While the galaxy candidate inspection is not yet quite complete, and
final number not yet determined, the survey has yielded about 1000 galaxies.
The data, in the form of three-dimensional datacubes, have been inspected by
eye, and candidate lists assembled, and about half have now been checked for
reality, and accepted into the final catalog. The distributions on the sky and
in redshift space are presented, showing galaxies belonging to previously-known
structures, and newly-discovered features. Of the 469 confirmed HI galaxies,
191 have a NIR source within 6 arcmin in the 2MASS Extended Source Catalog, but
the incidence of NIR counterparts is a strong function of longitude: in the low
obscuration, low stellar surface density Puppis region, 131 of the 186 HI
galaxies have 2MASS counterparts (70 percent), while in the Galactic bulge
region, only 6 of the 155 HI detections have a 2MASS extended source coincident
(4 percent). This is attributable to the HI survey's ability to detect galaxies
even in regions of high foreground stellar surface density.


title:
Observations of the X-ray Pulsar GX 301-2 with the ART-P Telescope of
  the Granat Observatory

abstract:
  The variability of the X-ray flux from the pulsar GX 301-2 is analyzed by
using data from the ART-P telescope of the Granat Observatory. The intensity
variations with time scales of several thousand seconds are studied at various
orbital phases. The high-state flux from the source exceeds its low-state flux
by as much as a factor of 10. The hardness and spectrum of the source are shown
to change greatly with its intensity. These intensity variations are most
likely caused by substantial inhomogeneities in the stellar wind from the
companion star.


title: The GUSBAD Catalog of Gamma-Ray Bursts

abstract:
  The GUSBAD catalog of gamma-ray bursts (GRBs) is based on archival BATSE
DISCLA data covering the full 9.1 years of the Compton Gamma Ray Observatory
mission. The catalog contains 2204 GRBs, including 589 bursts not listed in the
Current BATSE Burst Catalog. The GUSBAD catalog is uniform in the sense that
the detection criteria are the same throughout and that the properties given in
the catalog are available for every burst. The detection and the derivation of
the properties of the GRBs were carried out automatically. This makes the
GUSBAD catalog especially suitable for statistical work and simulations, such
as used in the derivation of V/Vmax. We briefly touch upon a potential problem
in defining a GRB duration that is physically meaningful.


title:
Kinematically Cold Populations at Large Radii in the Draco and Ursa
  Minor Dwarf Spheroidals

abstract:
  We present projected velocity dispersion profiles for the Draco and Ursa
Minor (UMi) dwarf spheroidal galaxies based on 207 and 162 discrete stellar
velocities, respectively. Both profiles show a sharp decline in the velocity
dispersion outside ~30 arcmin (Draco) and ~40 arcmin (UMi). New, deep
photometry of Draco reveals a break in the light profile at ~25 arcmin. These
data imply the existence of a kinematically cold population in the outer parts
of both galaxies. Possible explanations of both the photometric and kinematic
data in terms of both equilibrium and non-equilibrium models are discussed in
detail. We conclude that these data challenge the picture of dSphs as simple,
isolated stellar systems.


title:
Pulsational Analysis of the Cores of Massive Stars and its Relevance to
  Pulsar Kicks

abstract:
  The mechanism responsible for the natal kicks of neutron stars continues to
be a challenging problem. Indeed, many mechanisms have been suggested, and one
hydrodynamic mechanism may require large initial asymmetries in the cores of
supernova progenitor stars. Goldreich, Lai, & Sahrling (1997) suggested that
unstable g-modes trapped in the iron (Fe) core by the convective burning layers
and excited by the $\epsilon$-mechanism may provide the requisite asymmetries.
We perform a modal analysis of the last minutes before collapse of published
core structures and derive eigenfrequencies and eigenfunctions, including the
nonadiabatic effects of growth by nuclear burning and decay by both neutrino
and acoustic losses. In general, we find two types of g-modes: inner-core
g-modes, which are stabilized by neutrino losses and outer-core g-modes which
are trapped near the burning shells and can be unstable. Without exception, we
find at least one unstable g-mode for each progenitor in the entire mass range
we consider, 11 M$_{\sun}$ to 40 M$_{\sun}$. More importantly, we find that the
timescales for growth and decay are an order of magnitude or more longer than
the time until the commencement of core collapse. We conclude that the
$\epsilon$-mechanism may not have enough time to significantly amplify core
g-modes prior to collapse.


title: Radio Pulsars

abstract:
  The thesis focuses on different aspects of radio pulsars: on the one hand it
describes research on the pulsar emission mechanism (nulling, drifting
subpulses, single-pulse polarisation and their mutual interaction). On the
other it gives an account of investigations into the evolution of the pulsar
population as a whole (birthrates, velocities, magnetic field evolution) and
possible ways to probe this population (simulations of upcoming pulsar
surveys).


title: The Systemic Velocity of Eta Carinae

abstract:
  High-resolution spectra of molecular hydrogen in the Homunculus nebula allow
for the first direct measurement of the systemic velocity of Eta Carinae.
Near-infrared long-slit data for H2 1-0 S(1) lambda 21218 obtained with the
Phoenix spectrometer on the Gemini South telescope give Vsys=-8.1pm1 km/s
(heliocentric), or VLSR=-19.7pm1 km/s, from the average of the near and far
sides of the Homunculus. This measurement considerably improves the precision
for the value of -7pm10 km/s inferred from neighboring O-type stars in the
Carina nebula. New near-infrared spectra also provide a high-resolution line
profile of [Fe II] lambda 16435 emission from gas condensations known as the
Weigelt objects without contamination from the central star, revealing a line
shape with complex kinematic structure. Previously, uncertainty in the Weigelt
knots' kinematics was dominated by the adopted systemic velocity of Eta Car.


title: On the Growth of Dust Particles in a Non-Uniform Solar Nebula

abstract:
  A summary of the results of a numerical study of the growth of solid
particles in the vicinity of an azimuthally symmetric density enhancement of a
protostellar disk are presented. The effects of gas drag and pressure gradients
on the rate of growth of dust particles and their settling on the midplane of
the nebula are also discussed.


title:
Theoretical expectations for magnetic field measurements in molecular
  cloud cores

abstract:
  The currently most viable methods to estimate magnetic field strengths in
molecular cloud cores are Zeeman measurements and the Chandrasekhar-Fermi (CF)
method. The CF-method estimates magnetic field strengths from polarimetry and
relies on equipartition between the turbulent kinetic and turbulent magnetic
energy in the observed region. Thus, its application to objects not dominated
by hydromagnetic turbulence is questionable. We calibrate the CF-method and
Zeeman measurements against numerical models of self-gravitating molecular
cloud cores. We find -- in agreement with previous results -- that the
CF-method is on the average accurate up to a factor of 2, while a single
estimate can be off by a factor of 7. The CF-method is surprisingly robust even
when applied to regions not dominated by hydromagnetic turbulence and in the
face of small-number statistics. Zeeman measurements can systematically
overestimate the field strength in high-density regions, if the field is
predominantly oriented along the line of sight, while they tend to
underestimate the field in other cases.


title: Radioactive Krypton Background Evaluation Using Atom Counting

abstract:
  The beta-decay of $\rm^{85}Kr$ is a significant radioactive background for
experiments that use liquified noble gases to search for dark matter and
measure the low-energy solar neutrino flux. While there are several proposed
methods for reducing Kr levels in these experiments, an independent technique
is needed for measuring very low Kr levels. By selectively exciting Kr atoms to
a metastable state, capturing them in a magneto-optical trap (MOT), and
detecting fluorescence from the trapped atoms, individual Kr atoms can be
counted with a high signal-to-noise ratio. This approach could be used to
ascertain Kr impurity levels in other noble gases, with an estimated
sensitivity of $3\times 10^{-14}$.


title: The Mass Function of Void Galaxies in the SDSS Data Release 2

abstract:
  We estimate the Mass Function of void galaxies in the second public data
release of the Sloan Digital Sky Survey from a sample of 1000 galaxies with
local density contrasts of delta_v < -0.6. The galaxy sample is split into
ellipticals and spirals using a color-Sersic index criteria. We estimate the
virial masses of ellipticals using the measured spectral line-widths along with
the observed size. Projection effects and uncertainties in halo properties make
mass estimates of spirals more difficult. We use an inversion of the
Tully-Fisher relation to estimate the isothermal rotational velocity, and
introduce a scaling factor to estimate the halo extent. We then fit the
measured mass function against a theoretical Press-Schechter model, and find
that the distribution of galaxies in voids appears to be nearly unbiased
compared to the mass.


title: The Very Young Radio Pulsar J1357-6429

abstract:
  We report the discovery of a radio pulsar with a characteristic age of 7300
years, making it one of the 10 apparently youngest Galactic pulsars known. PSR
J1357-6429, with a spin period of P = 166 ms and spin-down luminosity of 3.1e36
ergs/s, was detected during the Parkes multibeam survey of the Galactic plane.
We have measured a large rotational glitch in this pulsar, with Delta P/P =
-2.4e-6, similar in magnitude to those experienced occasionally by the Vela
pulsar. At a nominal distance of only ~ 2.5 kpc, based on the measured free
electron column density of 127 pc/cc and the electron distribution model of
Cordes & Lazio, this may be, after the Crab, the nearest very young pulsar
known. The pulsar is located near the radio supernova remnant candidate
G309.8-2.6.


title: An X-ray census of young stars in the Chamaeleon I North cloud

abstract:
  Sensitive X-ray imaging surveys provide a new and effective tool to establish
the census of pre-main sequence (PMS) stars in nearby young stellar clusters.
We report here a deep Chandra X-ray Observatory observation of PMS stars in the
Chamaeleon I North cloud, achieving a limiting luminosity of log L_t ~ 27 erg/s
(0.5-8 keV band) in a 0.8x0.8 pc region. Of the 107 X-ray sources, 37 are
associated with Galactic stars of which 27 are previously recognized cloud
members. These include three PMS brown dwarfs; the protostellar brown dwarf ISO
192 has a particularly high level of magnetic activity. Followup optical
photometry and spectroscopy establishes that 9-10 of the Chandra sources are
probably magnetically active background stars. Several previously proposed
cloud members are also inferred to be interlopers due to the absence of X-ray
emission at the level expected from the L_t - K correlation. No new X-ray
discovered stars were confidently found despite the high sensitivity.
  From these findings, we argue that the sample of 27 PMS cloud members in the
Chandra field is uncontaminated and complete down to K = 12 or M ~ 0.1 Mo. The
initial mass function (IMF) derived from our sample is deficient in 0.1-0.3 Mo
stars compared to the IMF of the rich Orion Nebula Cluster and other Galactic
populations. We can not discriminate whether this is due to different star
formation processes, mass segregation, or dynamical ejection of lower mass
stars.


title: Probing Pre-Protosellar Cores with Formaldehyde

abstract:
  We present maps of the 6 cm and 1.3 mm transitions of formaldehyde toward
three cold, dense pre-protostellar cores: L1498, L1512, and L1544. The 6 cm
transition is a unique probe of high density gas at low temperature. However,
our models unequivocally indicate that H2CO is depleted in the interiors of
PPCs, and depletion significantly affects how H2CO probes the earliest stages
of star formation. Multi-stage, self-consistent models, including gas--dust
energetics, of both H2CO transitions are presented, and the implications of the
results are discussed.


title: A Window in the Dark Matter Exclusion Limits

abstract:
  We consider the cross section limits for light dark matter candidates
($m=0.4$ to 10 GeV). We calculate the interaction of dark matter in the crust
above underground dark matter detectors and find that in the intermediate cross
section range, the energy loss of dark matter is sufficient to fall below the
energy threshold of current underground experiments. This implies the existence
of a window in the dark matter exclusion limits in the micro-barn range.


title: The Magnetorotational Instability in the Kerr Metric

abstract:
  The magnetorotational instability (MRI) is the leading candidate for driving
turbulence, angular momentum transport, and accretion in astrophysical disks. I
consider the linear theory of the MRI in a thin, equatorial disk in the Kerr
metric. I begin by analyzing a mechanical model for the MRI that consists of
two point masses on nearly circular orbits connected by a spring. I then
develop a local Cartesian coordinate system for thin, equatorial Kerr disks. In
this local model general relativistic effects manifest themselves solely
through changes in the Coriolis parameter and in the tidal expansion of the
effective potential. The MRI can be analyzed in the context of the local model
using nonrelativistic magnetohydrodynamics, and the growth rates agree with
those found in the mechanical model. The maximum growth rate measured by a
circular orbit observer differs from a naive estimate using Newtonian gravity
by a factor that varies between 1 and 4/3 for all radii and for all a/M.


title:
The Angular Momentum Distribution of Gas and Dark Matter in Galactic
  Halos

abstract:
  (Abridged) We report results of a series of non radiative N-body/SPH
simulations in a LCDM cosmology. We find that the spin of the baryonic
component is on average larger than that of the dark matter (DM) component and
we find this effect to be more pronounced at lower redshifts. A significant
fraction f of gas has negative angular momentum and this fraction is found to
increase with redshift. We describe a toy model in which the tangential
velocities of particles are smeared by Gaussian random motions. This model is
successful in explaining some of the angular momentum properties. We compare
and contrast various techniques to determine the angular momentum distributions
(AMDs). We show that broadening of velocity dispersions is unsuitable for
making comparisons between gas and DM. We smooth the angular momentum of the
particles over a fixed number of neighbors. We find that an analytical function
based on gamma distribution can be used to describe a wide variety of profiles,
with just one parameter \alpha. The distribution of the shape parameter
$\alpha$ for both gas and DM follows roughly a log-normal distribution. The
mean and standard deviation of log(\alpha) for gas is -0.04 and 0.11
respectively. About 90-95% of halos have \alpha<1.3, while exponential disks in
NFW halos would require 1.3<\alpha<1.6. This implies that a typical halo in
simulations has an excess of low angular momentum material as compared to that
of observed exponential disks, a result which is consistent with the findings
of earlier works. \alpha for gas is correlated with that of DM but they have a
significant scatter <\alpha_Gas/\alpha_DM>=1.09 \pm 0.2. \alpha_Gas is also
biased towards slightly higher values compared to \alpha_DM.