title: Chemical analysis of 24 dusty (pre-)main-sequence stars

abstract:
  We have analysed the chemical photospheric composition of 24 Herbig Ae/Be and
Vega-type stars in search for the lambda Bootis phenomenon. We present the
results of the elemental abundances of the sample stars. Some of the stars were
never before studied spectroscopically at optical wavelengths. We have
determined the projected rotational velocities of our sample stars.
Furthermore, we discuss stars that depict a (selective) depletion pattern in
detail. HD 4881 and HD 139614 seem to display an overall deficiency. AB Aur and
possibly HD 126367 have subsolar values for the iron abundance, but are almost
solar in silicon. HD 100546 is the only clear lambda Bootis star in our sample.


title: Observations of convection in A-type stars

abstract:
  Convection and turbulence in stellar atmospheres have a significant effect on
the emergent flux from A-type stars. The recent theoretical advancements in
convection modelling have proved a challenge to the observers to obtain
measurements with sufficient precision and accuracy to allow discrimination
between the various predictions.
  A discussion of the current observational techniques used to evaluate the
various convection theories is presented. These include filter photometry,
spectrophotometry, hydrogen lines, and metal lines. The results from these
techniques are given, along with the successes and limitations.


title: The Li Overabundance of J37: Diffusion or Accretion?

abstract:
  In September 2002 the discovery of a super Li-rich F-dwarf (J37) in NGC 6633,
an iron poor analogue of the better studied Hyades and Praecepe open clusters,
was announced. This unique star was thought to be the smoking gun for the
action of diffusion, models of which predict a narrow "Li-peak" at
approximately the correct temperature. However, with more detailed studies into
J37s abundance pattern this star provides firm evidence for the accretion of
planetesimals or other material from the circumstellar environment of new born
stars.
  Thanks to the specific predictions made about the behaviour of Be abundances,
(the most striking of which being no Be in super-Li-rich dwarfs subject to
diffusion) the opposing diffusion/accretion predictions can be tested.
  Initial modelling of the Be line indicates that J37 is as Be rich as it is Li
rich; log N(Be) = 2.25 +/- 0.25, and so is broadly consistent with an
accretion-fuelled enhancement. However, that both Li and Be are enhanced by
much more than the iron-peak elements (as determined in previous studies)
suggests that diffusion also plays a role in increasing the abundances of Li
and Be specifically.
  Furthermore, a new data set from the UVES/UT2 combination has allowed the
elemental abundance of Iron to be measured, and the set of preliminary stellar
parameters determined; Teff ~ 7340 K, log g ~ 4.1, microturbulence ~ 4.3 km/s,
[Fe/H] ~ 0.50. This again provides distinct evidence for the effects of
accretion in J37 and requires a new synthesis of the Be doublet.


title: Probing Colliding Wind Binaries with High-Resolution X-ray Spectra

abstract:
  X-ray line profiles represent a new way of studying the winds of massive
stars. In particular, they enable us to probe in detail the wind-wind collision
in colliding wind binaries, providing new insights into the structure and
dynamics of the X-ray-emitting regions. We present the key results of new
analyses of high-resolution Chandra X-ray spectra of two important colliding
wind systems, Gamma Velorum and WR140. The lines of Gamma Vel are essentially
unshifted from their rest wavelengths, which we suggest is evidence of a wide
shock opening angle, indicative of sudden radiative braking. The widths of the
lines of WR140 are correlated with ionization potential, implying
non-equilibrium ionization. The implications of these results for the radio
emission from these systems are discussed, as are some of the future directions
for X-ray line profile modelling of colliding wind binaries.


title: Are there pulsars in the knee ?

abstract:
  Recent findings indicate that the Monogem Ring supernova remnant and the
associated pulsar PSR B0656+14 may be the 'Single Source' responsible for the
formation of the sharp knee in the cosmic ray energy spectrum at $\sim$3PeV. We
estimate the contribution of the pulsar B0656+14 to the cosmic rays in the PeV
region and conclude that the pulsar cannot contribute more than 15% to the
cosmic ray intensity at the knee. Therefore it cannot be the dominant source
there and an SNR is still needed.
  We also examine the possibility of the pulsar giving the peak of the
extensive air shower intensity observed from the region inside the Monogem
Ring. The estimates of the gamma-ray flux produced by cosmic ray particles from
this pulsar indicate that it can be the source of the observed peak, if the
particles were confined within the SNR during a considerable fraction of its
total age.
  We also estimate the contribution of Geminga and Vela pulsars to cosmic rays
at the knee.


title: Rotation periods of Post-T Tauri stars in Lindroos systems

abstract:
  We present a rotational study of Post-T Tauri stars (PTTSs) in Lindroos
systems, defined as binaries with early type primaries on the main-sequence
(MS) and late-type secondaries on the pre-main-sequence (PMS) phase. The
importance of this study in comparison with previous ones is that the Lindroos
sample is not X-ray selected so we avoid a possible bias towards fast rotators.
In this preliminary study we have monitored eleven stars in the UBVRI bands
during two campaigns of ten consecutive nights each. Eight of the observed
PTTSs show periodic modulations in their lightcurves and the derived periods
range from 1.9d to 8.0d. The comparison of these results with theoretical
rotational tracks based on disk-star locking theory shows that star-disk
decoupling times of 1-20 Myr could reproduce the rotational properties of the
targets, assuming an initial rotation period of ~8d and a mass of 1 Mo. We have
studied the rotation-activity relations of Lindroos PTTSs and compared them
with those found in other groups of PMS and zero-age main-sequence (ZAMS) ~1 Mo
stars. The Lindroos sample displays activity-rotation relations very similar to
those found in TTSs. It contains a mixture of very active stars, with Lx/Lbol
ratios close to the saturation level of -3, and less active (unsaturated)
stars. This could be the result of different star-disk decoupling times. Future
monitoring of a larger and unbiased sample of PTTS will be important to confirm
the significance of these results.


title: Accurate fundamental parameters of eclipsing binary stars

abstract:
  The study of detached eclipsing binaries is one of the most powerful ways to
investigate the properties of individual stars and stellar systems. We present
preliminary masses, radii and effective temperatures for the eclipsing binary
WW Aurigae, which is composed of two metallic-lined A-type stars. We also
reanalyse the data on HD 23642, an A-type eclipsing binary member of the
Pleiades open cluster with a metallic-lined component, and determine its
distance to be 139 +/- 4 pc. This is in agreement with the traditional Pleiades
distance, but in disagreement with distance to the Pleiades, and to HD 23642
itself, derived from Hipparcos trigonometrical parallaxes.


title:
The Parkes Multibeam Pulsar Survey: V. Finding binary and millisecond
  pulsars

abstract:
  The Parkes Multibeam Pulsar Survey is the most successful survey of the
Galactic plane ever performed, finding over 600 pulsars in the initial
processing. We report on reprocessing of all 40,000 beams with a number of
algorithms, including conventional frequency-domain searches and an
acceleration search for fast binary pulsars. The very large volume of results
coupled with the need to distinguish new candidates from known pulsars and
their many harmonics, often with multiple detections from different search
algorithms, necessitated the development of a new graphical selection tool
tightly linked to a web-based results database. We discuss and demonstrate the
benefits of these software systems which are specifically designed for large
survey projects. The results of this processing have been encouraging; we have
discovered 128 new pulsars including 11 binary and 15 millisecond pulsars, in
addition to those previously found in the survey, we have thus far discovered
737 pulsars. In this paper we discuss the discoveries of PSR J1744-3922, a 172
ms mildly recycled pulsar in a 4.6 hr orbit that exhibits nulling behaviour,
not previously observed in recycled or binary objects; PSR J1802-2124, an
intermediate mass binary pulsar (IMBP) and PSR J1801-1417, a solitary
millisecond pulsar.


title: Star Formation Properties of a Large Sample of Irregular Galaxies

abstract:
  We present the results of Halpha imaging of 94 irregular galaxies, including
types Im, BCD, and Sm. The sample spans a large range in galactic parameters
including integrated absolute magnitude (MV=-9 to -19), average surface
brightness (20 to 27 mag/arcsec2), current star formation activity (0 to 1.3
Msun/yr/kpc2), and relative gas content (0.02 to 5 Msun/LB). The Halpha images
were used to measure integrated star formation rates and extents of star
formation and to compare azimuthally-averaged radial profiles of current star
formation to older starlight. The integrated star formation rates of Im
galaxies normalized to the physical size of the galaxy span a range of a factor
of 10^4 with 10% Im galaxies and one Sm system having no measurable star
formation at the present time. The BCDs fall at the high end of the range of
rates. We find no correlation between star formation activity and proximity to
other catalogued galaxies. The cases with strong gradients in the L(Halpha)/LV
ratios and with high central star formation rate densities, which include most
of the BCDs, require a significant fraction of their gas to have migrated to
the center in the last Gyr. We discuss possible torques that could have caused
this without leaving an obvious signature, including dark matter bars and past
interactions or mergers with small galaxies or HI clouds. There is now
substantial evidence for these processes among many surveys of BCDs. The star
formation process itself does not appear to differ much among BCD, Im and Sm
types. There is evidence in the distribution function for Halpha surface
brightness, which is always approximately log-normal, that the turbulent Mach
numbers are about the same in these systems.


title: The power-law expansion universe and the late-time behavior

abstract:
  Using the SNe Ia data we determine the three parameters in the power-law
expanding universe model with time-dependent power \cite{W}. Inputting $H_0$
and $t_0$, then we find the $\dot{a}-t$ evolution curve with $m=5.0$ and
$q_0=-0.90$ can fit very well to that from SNe observation data. The model
predicts the transition redshift $z\simeq0.38$. The dark energy deduced from
this model have phantom property but the universe doesn't encounter the Big Rip
singularity. Assuming that this model with the three parameters is valid for
the future universe, then we predict that the total energy density of the
universe is decreasing and will soon reach its minimum.


title:
Variability in the stellar initial mass function at low and high mass:
  3-component IMF models

abstract:
  Three component models of the IMF are made to consider possible origins for
the observed relative variations in the numbers of brown dwarfs,
solar-to-intermediate mass stars, and high mass stars. Three distinct physical
processes are noted. The characteristic mass for most star formation is
identified with the thermal Jeans mass in the molecular cloud core, and this
presumably leads to the middle mass range by the usual collapse and accretion
processes. Pre-stellar condensations (PSCs) observed in mm-wave continuum
studies presumably form at this mass. Significantly smaller self-gravitating
masses require much larger pressures and may arise following dynamical
processes inside these PSCs, including disk formation, tight-cluster ejection,
and photoevaporation as studied elsewhere, but also gravitational collapse of
shocked gas in colliding PSCs. Significantly larger stellar masses form in
relatively low abundance by normal cloud processes, possibly leading to steep
IMFs in low-pressure field regions, but this mass range can be significantly
extended in high pressure cloud cores by gravitationally-focussed gas accretion
onto PSCs and by the coalescence of PSCs. These models suggest that the
observed variations in brown dwarf, solar-to-intermediate mass, and high mass
populations are the result of dynamical effects that depend on environmental
density and velocity dispersion. They accommodate observations ranging from
shallow IMFs in cluster cores to Salpeter IMFs in average clusters and whole
galaxies to steep and even steeper IMFs in field and remote field regions. They
also suggest how the top-heavy IMFs in some starburst clusters may originate
and they explain bottom-heavy IMFs in low surface brightness galaxies.


title: Late-type field stars in the RASS at high galactic latitude

abstract:
  We present results of an investigation on a high-galactic latitude sample of
late-type field stars selected from the ROSAT All-Sky Survey (RASS). The sample
comprises about 200 G, K, and M stars. Lithium abundances were determined for
about 180 G-M stars. Radial velocities were measured for most of the circ. 140
G and K type stars. Combined with proper motions these data were used to study
the age distribution and the kinematical properties of the sample. Based on the
lithium abundances half of the G-K stars were found to be younger than the
Hyades (660 Myr). About 30% are comparable in age to the Pleiades (100 Myr). A
small subsample of 10 stars is younger than the Pleiades (100 Myr). They are
therefore most likely pre-main sequence stars. Kinematically the PMS and
Pleiades-type stars appear to form a group with space velocities close to the
Castor moving group but clearly distinct from the Local Association.


title:
The applications of the MHD Alfven wave oscillation model for kHz
  quasi-periodic oscillations

abstract:
  In this paper, we improve the previous work on the MHD Alfven wave
oscillation model for the neutron star (NS) kHz quasi-periodic oscillations
(QPOs), and compare the model with the updated twin kHz QPO data. For the 17 NS
X-ray sources with the simultaneously detected twin kHz QPO frequencies, the
stellar mass M and radius R constraints are given by means of the derived
parameter A in the model, which is associated with the averaged mass density of
star as ${\rm \lan \rho \ran = 3M/(4\pi R^{3}) \simeq 2.4\times 10^{14}
(g/cm^{3}) (A/0.7)^{2}}$, and we also compare the M-R constraints with the star
equations of states. Moreover, we also discuss the theoretical maximum kHz QPO
frequency and maximum twin peak separation, and some expectations on SAX
J1808.4-3658 are mentioned, such as its highest kHz QPO frequency $\sim$~870
(Hz), which is about 1.4-1.5 times less than those of the other known kHz QPO
sources. The estimated magnetic fields for both Z sources (about Eddington
accretion rate $\med$) and Atoll sources ($ 1% \med$) are approximately $10^9$
G and $10^8$ G respectively.


title: Photometric Observations of the Type Ia SN 2002er in UGC 10743

abstract:
  Extensive light and colour curves for the Type Ia supernova SN 2002er are
presented as part of the European Supernova Collaboration. We have collected
UBVRI photometry from ten different telescopes covering the phases from 7 days
before until 619 days after maximum light. Corrections for the different
instrumental systems and the non-thermal spectrum of the supernova
(S-corrections) have been applied. With the densely sampled light curves we can
make detailed comparisons to other well-observed objects. SN 2002er most
closely resembles SN 1996X after maximum, but clearly shows a different colour
evolution before peak light and a stronger shoulder in V and R bands compared
to other well-observed SNe Ia. In particular, the rise time appears to be
longer than what is expected from rise-time vs.decline-rate relation. We use
several methods to determine the reddening towards SN 2002er based on the
colour evolution at near peak and at late phases. The uvoir (bolometric) light
curve shows great similarity with SN 1996X, but also indications of a higher
luminosity, longer rise time and a more pronounced shoulder 25 days past
maximum. The interpretation of the light curves was done with two independent
light curve codes. Both find that given the luminosity of SN 2002er the 56Ni
mass exceeds 0.6 Msun with prefered values near 0.7 Msun. Uncertainties in the
exact distance to SN 2002er are the most serious limitation of this
measurement. The light curve modelling also indicates a high level of mixing of
the nickel in the explosion of SN 2002er.


title: Disruption time scales of star clusters in different galaxies

abstract:
  The observed average lifetime of the population of star clusters in the Solar
Neighbourhood, the Small Magellanic Cloud and in selected regions of M51 and
M33 is compared with simple theoretical predictions and with the results of
N-body simulations. The empirically derived lifetimes (or disruption times) of
star clusters depend on their initial mass as t_dis ~ Mcl^0.60 in all four
galaxies. N-body simulations have shown that the predicted disruption time of
clusters in a tidal field scales as t_dis^pred ~ t_rh^0.75 t_cr^0.25, where
t_rh is the initial half-mass relaxation time and t_cr is the crossing time for
a cluster in equilibrium. We show that this can be approximated accurately by
t_dis^pred ~ M_cl^0.62 for clusters in the mass range of about 10^3 to 10^6
M_sun, in excellent agreement with the observations. Observations of clusters
in different extragalactic environments show that t_dis also depends on the
ambient density in the galaxies where the clusters reside. Linear analysis
predicts that the disruption time will depend on the ambient density of the
cluster environment as t_dis ~ rho_amb^-0.5. This relation is consistent with
N-body simulations.


title:
New evolutionary models for massive ZZ Ceti stars. II. The effects of
  crystallization on their pulsational properties

abstract:
  We present in this work new pulsational calculations for improved
carbon-oxygen DA white dwarf models suitable for the study of massive ZZ Ceti
stars. The background models employed in this study, presented in detail in a
recent paper by Althaus et al. (2003), are the result of the complete evolution
of massive white dwarf progenitors from the zero-age main sequence through the
Asymptotic Giant Branch (AGB) and mass loss phases to the white dwarf regime.
Abundance changes are accounted for by means of a full coupling between nuclear
evolution and time-dependent mixing due to convection, salt fingers, and
diffusive overshoot. In addition, time-dependent element diffusion for
multicomponent gases has been considered during the white dwarf evolution.
Crystallization and chemical rehomogenization due to phase separation upon
crystallization in the core of our models have been fully considered. The
effects of crystallization on the period spectrum of these massive white dwarf
models are assessed by means of a detailed pulsational analysis. We find that
the theoretical pulsation spectrum is strongly modified when crystallization is
considered, in particular concerning the mode trapping properties of the
equilibrium models. We also discuss at some length the implications of our
study for BPM 37093, the most massive ZZ Ceti star presently known. We find
that if BPM 37093 has a stellar mass of $\approx 1.00$ \msun its observed
spectrum could bear the signature of overshoot episodes during the helium core
burning.


title: The rate of period change in pulsating DB white dwarf stars

abstract:
  In this work, we present the theoretically expected rates of pulsation period
change for V777 Her (DBV) variable stars. To this end we employ new
evolutionary models representative of pulsating DB white dwarf stars computed
in a self-consistent way with the predictions of time-dependent element
diffusion. At the hot edge of the DB instability strip, the envelopes of the
models are characterized by a diffusion-induced double-layered chemical
structure. We compute the numerical values of rates of period change by solving
the equations of linear, adiabatic, nonradial stellar oscillations. We examine
the effects of varying the stellar mass, the mass of the helium envelope and
the neutrino emission on the expected period changes. We present extensive
tabulations of our results which could be useful for comparison with future
detections of the rate of period change in pulsating DB white dwarfs.


title:
Pulsations of massive ZZ Ceti stars with carbon/oxygen and oxygen/neon
  cores

abstract:
  We explore the adiabatic pulsational properties of massive white dwarf stars
with hydrogen-rich envelopes and oxygen/neon and carbon/oxygen cores. To this
end, we compute the cooling of massive white dwarf models for both core
compositions taking into account the evolutionary history of the progenitor
stars and the chemical evolution caused by time-dependent element diffusion. In
particular, for the oxygen/neon models, we adopt the chemical profile resulting
from repeated carbon-burning shell flashes expected in very massive white dwarf
progenitors. For carbon/oxygen white dwarfs we consider the chemical profiles
resulting from phase separation upon crystallization. For both compositions we
also take into account the effects of crystallization on the oscillation
eigenmodes. We find that the pulsational properties of oxygen/neon white dwarfs
are notably different from those made of carbon/oxygen, thus making
asteroseismological techniques a promising way to distinguish between both
types of stars and, hence, to obtain valuable information about their
progenitors.


title: The status of the ANTARES experiment

abstract:
  ANTARES is a neutrino telescope designed to search for high-energy neutrinos
from astrophysical sources such as quasars, gamma-ray bursters, microquasars,
supernova remnants and AGN. The objectives also include the indirect search for
WIMPs, primary candidates for non-baryonic dark matter, by looking for
neutrinos from neutralino annihilations in the centres of the Sun, Earth and
Galaxy. The array of 12 lines with 900 photomultiplier tubes will be deployed
by 2007 at a depth of about 2500 m in the Mediterranean sea near Toulon
(France), 40 km off the coast. It will detect the Cherenkov light emitted in
sea water by muons produced via charged-current interactions of neutrinos with
surrounding matter. A prototype line and an instrumentation line for monitoring
environmental parameters have been successfully deployed and connected to the
electro-optical cable, which transmitted the data to the shore station. The
current status of the project is presented.


title:
The Solar Neighborhood X: New Nearby Stars in the Southern Sky and
  Accurate Photometric Distance Estimates for Red Dwarfs

abstract:
  Photometric VRI and spectroscopic (6000-9500 A) observations of high proper
motion stars discovered during the first phase of the SuperCOSMOS RECONS (SCR)
search are used to estimate accurate distances to eight new nearby red dwarfs,
including probable 10 pc sample members SCR 1845-6357 (M8.5V at 4.6 pc), the
binary SCR 0630-7643AB (M6.0VJ at 7.0 pc), and SCR 1138-7721 (M5.0V at 9.4 pc).
Distance estimates are determined using a suite of new photometric color-Mk
relations defined using a robust set of nearby stars with accurate VRIJHK
photometry and trigonometric parallaxes.
  These relations are utilized, with optical and infrared photometry, to
estimate distances on a uniform system (generally good to 15%) for two
additional samples of red nearby star candidates: several recently discovered
members of the solar neighborhood, and known faint stars with proper motions in
excess of 1.0"/yr south of DEC = -57.5. Of those without accurate trigonometric
parallax measurements, there are five stars in the first sample and three in
the second that are likely to be within 10 pc. The two nearest are SO 0253+1652
(M7.0V at 3.7 pc) and DEN 1048-3956 (M8.5V at 4.5 pc). When combined with SCR
1845-6357, these three stars together represent the largest increase in the 5
pc sample in several decades.
  Red spectra are presented for the red dwarfs and types are given on the
RECONS standard spectral system. Red spectra are also given for two new nearby
white dwarfs for which we estimate distances from the photometry of less than
20 pc -- WD 0141-675 (LHS 145, 9.3 pc) and SCR 2012-5956 (17.4 pc). WD 0141-675
brings the total number of systems nearer than 10 pc discussed in this paper to
12.


title: Why Buckling Stellar Bars Weaken in Disk Galaxies

abstract:
  Young stellar bars in disk galaxies experience a vertical buckling
instability which terminates their growth and thickens them, resulting in a
characteristic peanut/boxy shape when viewed edge on. Using N-body simulations
of galactic disks embedded in live halos, we have analyzed the bar structure
throughout this instability and found that the outer third of the bar dissolves
completely while the inner part (within the vertical inner Lindblad resonance)
becomes less oval. The bar acquires the frequently observed peanut/boxy-shaped
isophotes. We also find that the bar buckling is responsible for a mass
injection above the plane, which is subsequently trapped by specific 3-D
families of periodic orbits of particular shapes explaining the observed
isophotes, in line with previous work. Using a 3-D orbit analysis and surfaces
of sections, we infer that the outer part of the bar is dissolved by a rapidly
widening stochastic region around its corotation radius -- a process related to
the bar growth. This leads to a dramatic decrease in the bar size, decrease in
the overall bar strength and a mild increase in its pattern speed, but is not
expected to lead to a complete bar dissolution. The buckling instability
appears primarily responsible for shortening the secular diffusion timescale to
a dynamical one when building the boxy isophotes. The sufficiently long
timescale of described evolution, ~1 Gyr, can affect the observed bar fraction
in local universe and at higher redshifts, both through reduced bar strength
and the absence of dust offset lanes in the bar.


title: Investigating the origins of the CMB-XRB cross correlation

abstract:
  Recently, we presented evidence for a cross-correlation of the WMAP satellite
map of the cosmic microwave background (CMB) and the HEAO1 satellite map of the
hard X-ray background (XRB) with a dimensionless amplitude of 0.14 +- 0.05
normalized to the product of the rms fluctuations of the CMB and XRB (Boughn &
Crittenden, 2004). Such a correlation is expected in a universe dominated by a
cosmological constant via the integrated Sachs-Wolfe (ISW) effect and the level
of the correlation observed is consistent with that predicted by the currently
favored Lambda cold dark matter model of the universe. Since this offers
independent confirmation of the cosmological model, it is important to verify
the origin of the correlation. Here we explore in detail some possible
foreground sources of the correlation. The present evidence all supports an ISW
origin.


title: Binary Lenses in OGLE-III EWS Database. Seasons 2002--2003

abstract:
  We present 15 binary lens candidates from OGLE-III Early Warning System
database for seasons 2002-2003. We also found 15 events interpreted as single
mass lensing of double sources. The candidates were selected by visual light
curves inspection. Examining the models of binary lenses of this and our
previous study (10 caustic crossing events of OGLE-II seasons 1997-1999) we
find one case of extreme mass ratio binary (q ~ 0.005) and the rest in the
range 0.1<q<1.0, which may indicate the division between planetary systems and
binary stars. There is no strong discrepancy between the expected and the
observed distributions of mass ratios and separations for binary stars.


title:
On the Evolutionary Status of Class I Stars and Herbig-Haro Energy
  Sources in Taurus-Auriga

abstract:
  [abridged] We present high resolution optical spectra of stars in
Taurus-Auriga whose circumstellar environment suggests that they are less
evolved than optically revealed T Tauri stars. Many of the stars are seen only
via scattered light. These spectra are used to search for differences between
stars which power Herbig-Haro flows and stars which do not, and to reassess the
evolutionary state of so-called protostars (Class I stars) relative to
optically revealed T Tauri stars (Class II stars). The stellar mass
distribution of Class I stars is similar to that of Class II stars and includes
3 Class I brown dwarfs. Class I stars in Taurus are slowly rotating; the
angular momentum of a young star appears to dissipate prior to the optically
revealed T Tauri phase. The mass accretion rates of Class I stars are
surprisingly indistinguishable from those of Class II stars; they do not have
accretion dominated luminosities. We confirm previous results that find larger
forbidden-line emission associated with Class I stars than Class II stars. We
suggest that this is caused by an orientation bias that allows a more direct
view of the somewhat extended forbidden emission line regions than the obscured
stellar photospheres, rather than because of larger mass outflow rates.
Overall, the similar masses, luminosities, rotation rates, mass accretion
rates, mass outflow rates, and millimeter flux densities of Class I and Class
II stars are best explained by a scenario in which most Class I stars are no
longer in the main accretion phase and are older than traditionally assumed.
Similarly, although stars which power Herbig-Haro flows appear to have larger
mass outflow rates, their stellar and circumstellar properties are generally
indistinguishable from those of stars that do not power these flows.


title: Cluster arc statistics

abstract:
  We study the strong gravitational lensing properties of galaxy clusters
obtained from N-body simulations with standard $\Lambda$CDM cosmology. We have
used the 32 most massive clusters from a simulation at various redshifts and
ray-traced through the clusters to investigate the giant arcs statistics. We
have investigated the prevalence of multiple arc system, by looking at the
multiple arc fraction (defined in the paper) systematically in various clusters
and we have found that $\sim 40-50%$ of the clusters that produce giant arcs
give multiple arcs, which agrees with the RCS{\sc ii} observations. We have
also investigated the mass distributions that are efficient in lensing,
discussed effects of source sizes and various other factors that are very
important in the formation of giant arcs.


title: How a brane cosmological constant can trick us into thinking that w < -1

abstract:
  Observations exploring the contemporary cosmic acceleration have sparked
interest in dark energy models possessing equations of state with w < -1. We
review how the cosmic expansion history of a Dvali-Gabadadze-Porrati (DGP)
braneworld model with a standard brane cosmological constant can mimic that of
ordinary 4-dimensional gravity with w < -1 "phantom" dark energy for
observationally relevant redshifts. We reinterpret the effective phantom nature
of the dark energy as arising from dynamical-screening of the brane
cosmological constant in DGP. This unusual variety of expansion history is thus
possible without violating the null-energy condition, without ghosts and
without any big rip, in a model which seems no more contrived than most
evolving dark energy models. We indicate ways by which one may observationally
test this effective w < -1 possibility, and differentiate it from ``ordinary''
phantom dark-energy.


title:
The Galactic Formation Rate of Eccentric Neutron Star-White Dwarf
  Binaries

abstract:
  In this paper we consider the population of eccentric binaries with a neutron
star and a white dwarf that has been revealed in our galaxy in recent years
through binary pulsar observations. We apply our statistical analysis method
(Kim, Kalogera, & Lorimer 2003)and calculate the Galactic formation rate of
these binaries empirically. We then compare our results with rate predictions
based on binary population synthesis from various research groups and for
various ranges of model input parameters. For our reference moel, we find the
Galactic formation rate of these eccentric systems to be ~7 per Myr, about an
order of magnitude smaller than results from binary evolution estimations.
However, the empirical estimates are calculated with no correction for pulsar
beaming, and therefore they should be taken as lower limits. Despite
uncertainties that exceed an order of magnitude, there is significant overlap
of the various rate calculations. This consistency lends confidence that our
current understanding of the formation of these eccentric NS-WD binaries is
reasonable.


title: The Anatomy of Star Formation in NGC 300

abstract:
  The Spitzer Space Telescope was used to study the mid-infrared to
far-infrared properties of NGC 300, and to compare dust emission to Halpha to
elucidate the heating of the ISM and the star formation cycle at scales < 100
pc. The new data allow us to discern clear differences in the spatial
distribution of 8 micron dust emission with respect to 24 micron dust and to
HII regions traced by the Halpha light. The 8 micron emission highlights the
rims of HII regions, and the 24 micron emission is more strongly peaked in star
forming regions than at 8 microns. We confirm the existence and approximate
amplitude of interstellar dust emission at 4.5 microns, detected statistically
in Infrared Space Observatory (ISO) data, and conclude it arises in star
forming regions. When averaging over regions larger than ~ 1 kpc, the ratio of
Halpha to Aromatic Feature emission in NGC 300 is consistent with the values
observed in disks of spiral galaxies. The mid-to-far-infrared spectral energy
distribution of dust emission is generally consistent with pre-Spitzer models.


title:
A reappraisal of the chemical composition of the Orion nebula based on
  VLT echelle spectrophotometry

abstract:
  We present VLT UVES echelle spectrophotometry of the Orion nebula in the 3100
to 10400 A range. We have measured the intensity of 555 emission lines, many of
them corresponding to permitted lines of different heavy-element ions. This is
the largest set of spectral emission lines ever obtained for a Galactic or
extragalactic HII region. We have derived He+, C++, O+, O++ and Ne++ abundances
from pure recombination lines. This is the first time that O+ and Ne++
abundances are obtained from this kind of lines in the nebula. We have also
derived abundances from collisionally excited lines for a large number of ions
of different elements. In all cases, ionic abundances obtained from
recombination lines are larger than those derived from collisionally excited
lines. We have obtained remarkably consistent independent estimations of the
temperature fluctuations parameter, t2, from different methods, which are also
similar to other estimates from the literature. This result strongly suggests
that moderate temperature fluctuations -t2 between 0.02 and 0.03- are present
in the Orion nebula. We have compared the chemical composition of the nebula
with those of the Sun and other representative objects. The heavy element
abundances in the Orion nebula are only slightly higher than the solar ones, a
difference that can be explained by the chemical evolution of the solar
vicinity.


title:
Light curves and polarization of accretion- and nuclear-powered
  millisecond pulsars

abstract:
  We study theoretical X-ray light curves and polarization properties of
accretion-powered millisecond pulsars. We assume that the radiation is produced
in two antipodal spots at the neutron star surface which are associated with
the magnetic poles. We compute the angle-dependent intensity and polarization
produced in an electron-scattering dominated plane-parallel accretion shock in
the frame of the shock. The observed flux, polarization degree and polarization
angle are calculated accounting for special and general relativistic effects.
The calculations also extended to the case of nuclear-powered millisecond
pulsars -- X-ray bursts. In this case, we consider one spot and the radiation
is assumed to be produced in the atmosphere of the infinite Thomson optical
depth. The light curves and polarization profiles show a large diversity
depending on the model parameters. Presented results can be used as a first
step to understand the observed pulse profiles of accretion- and
nuclear-powered millisecond pulsars. Future observations of the X-ray
polarization will provide a valuable tool to test the geometry of the emission
region and its physical characteristics.


title:
Intrinsic Inclination of Galaxies embedded in Cosmic Sheets and its
  Cosmological Implications: An Analytic Calculation

abstract:
  We investigate analytically a large-scale coherence in the orientation of
galaxies embedded in two-dimensional sheet-like structures in the frame of the
tidal torque theory. Assuming that the galaxy spin and the surrounding matter
fields are intrinsically aligned in accordance with the tidal torque model, we
first derive analytically the probability distribution of the galaxy position
angles, and evaluate the degree of their inclinations relative to the plane of
the sheet. Then, we apply our analytic approach to the nearby spirals in the
Local Super Cluster, and provide theoretical explanations about why and to what
degree the nearby spirals are inclined relative to the supergalatic plane.
Finally, we conclude that the observed large-scale coherence in the orientation
of nearby spirals relative to the supergalactic plane can be quantitatively
understood in terms of galaxy intrinsic alignment predicted by the tidal torque
theory, and that the spins of luminous galaxies might be more strongly aligned
with the surrounding matter than the underlying dark halos. If applied to large
scale surveys like Sloan Digital Sky Survey (SDSS), our analytic approach will
allow us to measure accurately the strength of galaxy intrinsic alignment which
plays a role of statistical error in weak lensing searches and can be used as a
fossil record to reconstruct cosmology.


title:
Cross-correlation of the CMB and radio galaxies in real, harmonic and
  wavelet spaces: detection of the integrated Sachs-Wolfe effect and dark
  energy constraints

abstract:
  We report the first detection of the ISW effect in wavelet space, at scales
in the sky around 7 degrees with a significance of around 3.3 sigma, by
cross-correlating the WMAP first-year data and the NRAO VLA Sky Survey (NVSS).
In addition, we present a detailed comparison among the capabilities of three
different techniques for two different objectives: to detect the ISW and to put
constraints in the nature of the dark energy. The three studied techniques are:
the cross-angular power spectrum (CAPS, harmonic space), the correlation
function (CCF, real space) and the covariance of the Spherical Mexican Hat
Wavelet (SMHW) coefficients (CSMHW, wavelet space). We prove that the CSMHW is
expected to provide a higher detection of the ISW effect for a certain scale.
This prediction has been corroborated by the analysis of the data. The SMHW
analysis shows that the cross-correlation signal is caused neither by
systematic effects nor foreground contamination. However, by taking into
account the information encoded in all the multipoles/scales/angles, the CAPS
provides slightly better constraints than the SMHW in the cosmological
parameters that define the nature of the dark energy. The limits provided by
the CCF are wider than for the other two methods. Two different cases have been
studied: 1) a flat Lambda-CDM universe and 2) a flat universe with an equation
of state parameter different from -1. In the first case, the CAPS provides (for
a bias value of b = 1.6) 0.59 < Lambda density < 0.84 (at 1 sigma CL).
Moreover, the CAPS rejects the range Lambda density < 0.1 at 3.5 sigma, which
is the highest detection of the dark energy reported up to date. In the second
case, the CAPS gives 0.50 < dark energy density < 0.82 and -1.16 < w < 0.43 (at
1 sigma CL).


title:
Line profile variability in the spectra of Oef stars: II. HD192281,
  HD14442 and HD14434

abstract:
  We present the very first analysis of the spectroscopic variability of the
three rapidly rotating Oef stars HD192281 (O5(ef)), HD14442 (O5.5ef) and
HD14434 (O6.5(ef)). Radial velocities of the HeII lambda 4541 line reveal no
evidence of binarity on time scales of a few days, or from one year to the
next, for any of the targets. The HeII lambda 4686 double-peaked emission and,
to some extent, the Hbeta absorption line display significant profile
variability in the spectra of all three stars. Data gathered during different
observing runs spread over six years reveal a rather stable time scale for
HD192281 and HD14442, whereas the variability pattern changes significantly
from one year to the other. The case of HD14434 is less clear as no obvious
time scale emerges from our analysis. In a temptative way to interpret this
variability, stellar rotation remains a possible clock for HD192281 and
HD14442. However, currently available models addressing stellar rotation fail
to explain some crucial aspects of the observed variability behaviour, which
appear to be even more complex in the case of HD14434.


title:
Subaru Spectropolarimetry of Mrk 573: The Hidden High-Ionization Nuclear
  Emission-Line Region inside the Dusty Torus

abstract:
  We report on the result of our high quality spectropolarimetric observation
for the narrow-line region in a nearby Seyfert 2 galaxy, Mrk 573, by the Subaru
Telescope. The polarized flux spectrum of Mrk 573 shows not only prominent
scattered broad H$\alpha$ emission but also various narrow forbidden emission
lines. We find that the measured polarization degree of the observed forbidden
emission lines is positively correlated with the ionization potential of the
corresponding ions and the critical density of the corresponding transitions.
We discuss some possible origins of these correlations, and then we point out
that the correlations are caused due to the obscuration of the stratified
narrow-line region in Mrk 573 by the optically and geometrically thick dusty
torus, just similar to the previous study on NGC 4258.


title:
A Strong Lyman-alpha Emitter at z=6.33 in the Subaru Deep Field Selected
  as an i' Dropout

abstract:
  We report on the discovery of a star-forming galaxy at z=6.33 in the Subaru
Deep Field. This object is selected as a candidate of an i'-dropout,
high-redshift galaxy around z=6 because of its red i'-z' color in our deep
optical imaging survey in the Subaru Deep Field. Our follow up optical
spectroscopy reveals that this object is a strong Ly-alpha emitter with only
very faint ultraviolet continuum. The rest-frame equivalent width of the
detected Ly-alpha emission is as much as 130 A. Thus the light detected in our
z' image is largely attributed to the Ly-alpha emission, i.e., ~40% of the
z'-band flux is the strong Ly-alpha emission, giving a very red i'-z' color.
This is consistent with the photometric property of this object because the
narrow-band data obtained with the NB921 filter shows a significant depression,
z'-NB921 = -0.54 mag. By using the photometric data, we show that some other
objects among the 48 i'-dropout high-redshift galaxy candidates found in the
Subaru Deep Field also show a significant NB921 depression. We briefly discuss
the nature of these NB921-depressed objects.


title: GAIA -- Composition, Formation and Evolution of our Galaxy

abstract:
  GAIA will provide a multi-colour photometric and astrometric census of some
one billion compact sources, complete to 20th magnitude. In addition, spectra
for radial velocities will be obtained for about 30 million stars brighter than
V=17. The high spatial resolution and astrometric precision, 0.1arcsec and
10microarcsec to V=15, will not only quantify the distribution of mass and the
stellar populations in the Galaxy, but make major advances in fundamental
physics, cosmology and solar system science. GAIA is an ESA mission, scheduled
for launch in mid-2011. A full description of the GAIA project and science
case, fairly crediting the hundreds of contributors, is available in the
project `Red Book' [ESA-SCI(2000)4]. A brief overview is provided by Perryman,
de Boer, Gilmore, et al (2001). The www site is http://www.rssd.esa.int/GAIA/


title: The 2MASS-selected Flat Galaxy Catalog

abstract:
  An all-sky catalog of 18020 disc-like galaxies is presented. The galaxies are
selected from the Extended Source Catalog of the Two Micron All-Sky Survey (XSC
2MASS) basing on their 2MASS axial ratio a/b >= 3. The Catalog contains data on
magnitudes of a galaxy in the J, H, K_s bands, its axial ratio, positional
angle, index of luminosity concentration, as well as identification of the
galaxy with the LEDA and the NED databases. Unlike the available optical
catalogs, the new 2MFGC catalog seems to be more suitable to study cosmic
streaming on a scale of z <= 0.1. The dipole moment of distribution of the
bright (K < 11 mag) 2MFGC objects (l = 227 degr, b = 41 degr or SGL = 90 degr,
SGB = -43 degr) lies within statistical errors (+/- 15 degr) in the direction
of the IRAS dipole and the optical RFGC dipole.


title: INTEGRAL detection of a long powerful burst from SLX1735-269

abstract:
  We present results of analysis of a bursting behavior of a low mass X-ray
binary system SLX 1735-269 during INTEGRAL observations of the Galactic Center
region in 2003. There were detected 6 type I X-ray bursts in total, with one
being much longer and more powerful then others. A strong dependence of the
bursts recurrence time on the mass accretion rate is observed, that is likely
caused by the change in the burning regime. The long burst demonstrated a
photospheric radius expansion. We discuss possible scenarios of this long burst
and show that it is unlikely a carbon burning flash and rather a burst of large
pile of hydrogen and helium accelerated by electron capture processes in a
dense accumulated layer.


title: A Statistical Investigation of HI in the Magellanic Bridge

abstract:
  We present results from two statistical analyses applied to an neutral
hydrogen (HI) dataset of the nearby tidal bridge in the Magellanic System.
Primarily, analyses of the Spatial Power Spectrum suggest that the Magellanic
Bridge, historically considered to be a single contiguous feature, may in fact
be a projection of two kinematically and morphologically distinct structures.
The southern and more obviously turbulent parts appear to show structure
organized similarly to the adjacent Small Magellanic Cloud (SMC), while the
northern regions are shown to be relatively deficient in large scale power. The
extent of modification to the spatial power index by the velocity fluctuations
is also highly variant across these parts of the Bridge. We find again that the
northern part appears distinct from the southern part and from the SMC, in that
the power spectrum is significantly more affected by slower velocity
perturbations.
  We also probe the rate of spectral variation of the HI by measuring the
Spectral Correlation Function over selected regions. The results from this
analysis highlight a tendency for the HI spectra within the bright parts of the
Bridge to have a more persistent correlation in the E-W direction than in the
N-S direction. These results are considered to be quantitative evidence for the
tidal processes which are thought to have been active throughout the evolution
of the Magellanic Bridge


title: Far-Ultraviolet Observations of RR Lyrae Stars in the Core of NGC 1851

abstract:
  There are extraordinarily few far ultraviolet observations of RR Lyrae stars
in the literature. We present Hubble Space Telescope FUV (~1600 A) imaging of
the core of the globular cluster NGC 1851. Eleven new variables whose light
curves are consistent with those of RR Lyr stars are discovered, increasing the
total number of RR Lyr known in this cluster by a substantial amount. In
agreement with basic physical theory, the observed amplitude of the variables
in the FUV is enormous compared with the century of past optical observations,
ranging up to 4 mag. HST STIS FUV observations of cluster cores may prove an
especially effective means of obtaining a near-complete census of RR Lyr stars,
combining high angular resolution, suppression of luminous red stars, and data
where the stellar pulsation amplitudes are greatly enhanced. Attention is also
drawn to a peculiar blue object in the cluster that is most probably a low mass
x-ray binary system in quiescence.


title:
Downscattering due to Wind Outflows in Compact X-ray Sources: Theory and
  Interpretation

abstract:
  A number of recent lines of evidence point towards the presence of hot,
out-flowing plasma from the central regions of compact Galactic and
extragalactic X-ray sources. Additionally, it has long been noted that many of
these sources exhibit an ``excess'' continuum component, above 10 keV, usually
attributed to Compton Reflection from a static medium. Motivated by these
facts, as well as by recent observational constraints on the Compton reflection
models - specifically apparently discrepant variability timescales for line and
continuum components in some cases -- we consider possible effects of
out-flowing plasma on the high-energy continuum spectra of accretion powered
compact objects. We present a general formulation for photon downscattering
diffusion which includes recoil and Comptonization effects due to divergence of
the flow. We then develop an analytical theory for the spectral formation in
such systems that allows us to derive formulae for the emergent spectrum.
Finally we perform the analytical model fitting on several Galactic X-ray
binaries. Objects which have been modeled with high-covering-fraction Compton
reflectors, such as GS1353-64 are included in our analysis. In addition, Cyg
X-3, is which is widely believed to be characterized by dense circumstellar
winds with temperature of order 10^6 K, provides an interesting test case. Data
from INTEGRAL and RXTE covering the 3-300 keV range are used in our analysis.
We further consider the possibility that the widely noted distortion of the
power-law continuum above 10 keV may in some cases be explained by these
spectral softening effects.


title: The LyB and OVI Forest in the Local Universe

abstract:
  Intergalactic absorbers along lines of sight to distant quasars are a
powerful diagnostic for the evolution and content of the IGM. In this study, we
search known low-z Ly-alpha absorption systems for equivalent absorption in
higher Lyman lines as well as the important metal ions OVI and CIII. OVI
absorption is detected roughly half the time and shows a smaller range of
column density than HI. This implies a multi-phase IGM with warm neutral and
hot ionized components. We use our OVI detection statistics to determine that
the fraction of intergalalctic mass at 10^5-10^6 K is at least 5% of the total
baryonic mass in the local (z<0.15) universe.


title: GMC Formation in M33: the Role of Pressure

abstract:
  We present a complete map of the Giant Molecular Clouds in M33 and show that
they lie exclusively on filaments of HI. The GMCs are localized on the extended
HI filaments, and HI filaments extend well beyond the radius where the GMCs are
found, suggesting that the H_2 forms from the HI and not vice-versa. We propose
that the fraction of neutral gas that is molecular at a particular radius is
determined primarily by the ambient hydrostatic pressure at that radius. This
leads to a prediction that the transition radius, the radius where the mean
surface density of HI and H_2 are equal, occurs at a constant value of the
stellar surface density. We show that for a sample of 26 galaxies, the stellar
surface density at the transition radius is constant to 40%.


title:
Survey of Instantaneous 1-22 GHz Spectra of 550 Compact Extragalactic
  Objects with Declinations from -30deg to +43deg

abstract:
  We present observational results for extragalactic radio sources with
milliarcsecond components, obtained with the 600 meter ring radio telescope
RATAN-600 from 1st to 22nd December, 1997. For each source, a six frequency
broad band radio spectrum was obtained by observing simultaneously with an
accuracy up to a minute at 1.4, 2.7, 3.9, 7.7, 13 and 31 cm. The observed list
is selected from Preston et al. (1985) VLBI survey and contains all the sources
in the declinations between -30deg and +43deg with a correlated flux density
exceeding 0.1 Jy at 13 cm. The sample includes the majority of sources to be
studied in the current VSOP survey and the future RadioAstron Space VLBI
mission.


title: The Progenitor of the Type II-P SN 2004dj in NGC 2403

abstract:
  The Type II-P supernova 2004dj in the nearby galaxy NGC 2403 occurred at a
position coincident with object 96 in the list of luminous stars and clusters
in this galaxy published by Sandage in 1984. The coincidence is established
definitively through astrometric registration of our ground-based archival
images of NGC 2403 with our recent images showing the SN. The archival images
show that Sandage 96 is slightly resolved from the ground. Pre-outburst blue
spectrograms obtained by Humphreys and Aaronson reveal that Sandage 96 has a
composite spectrum, dominated in the blue region by A- and B-type stars, while
infrared photometry shows that Sandage 96 also contains red supergiants. These
results demonstrate that Sandage 96 is a young compact cluster. We have studied
the stellar population of Sandage 96, using published photometric measurements
combined with a chi-square-fitting code. We derive a cluster age of 13.6 Ma, a
reddening of E(4405-5495)=0.172, and a total stellar mass of 24 000 M_Sun. For
this cluster age, the SN progenitor had a main-sequence mass of 15 M_Sun.
Post-outburst photometry of Sandage 96 may establish whether the progenitor was
a red or blue supergiant.


title:
Precise Localization of the Soft Gamma Repeater SGR 1627-41 and the
  Anomalous X-ray Pulsar AXP 1E1841-045 with Chandra

abstract:
  We present precise localizations of AXP 1E1841-045 and SGR 1627-41 with
Chandra. We obtained new infrared observations of SGR 1627-41 and reanalyzed
archival observations of AXP 1E1841-045 in order to refine their positions and
search for infrared counterparts. A faint source is detected inside the error
circle of AXP 1E1841-045. In the case of SGR 1627-41, several sources are
located within the error radius of the X-ray position and we discuss the
likelihood of one of them being the counterpart. We compare the properties of
our candidates to those of other known AXP and SGR counterparts. We find that
the counterpart candidates for SGR 1627-41 and SGR 1806-20 would have to be
intrinsically much brighter than AXPs to have detectable counterparts with the
observational limits currently available for these sources. To confirm the
reported counterpart of SGR 1806-20, we obtained new IR observations during the
July 2003 burst activation of the source. No brightening of the suggested
counterpart is detected, implying that the counterpart of SGR 1806-20 remains
yet to be identified.


title:
Evolution and Impact of Bars over the Last Eight Billion Years: Early
  Results from GEMS

abstract:
  Bars drive the dynamical evolution of disk galaxies by redistributing mass
and angular momentum, and they are ubiquitous in present-day spirals. Early
studies of the Hubble Deep Field reported a dramatic decline in the rest-frame
optical bar fraction f_opt to below 5% at redshifts z>0.7, implying that disks
at these epochs are fundamentally different from present-day spirals. The GEMS
bar project, based on ~8300 galaxies with HST-based morphologies and accurate
redshifts over the range 0.2-1.1, aims at constraining the evolution and impact
of bars over the last 8 Gyr. We present early results indicating that f_opt
remains nearly constant at ~30% over the range z=0.2-1.1,corresponding to
lookback times of ~2.5-8 Gyr. The bars detected at z>0.6 are primarily strong
with ellipticities of 0.4-0.8. Remarkably, the bar fraction and range of bar
sizes observed at z>0.6 appear to be comparable to the values measured in the
local Universe for bars of corresponding strengths. Implications for bar
evolution models are discussed.


title: Spectroscopic monitoring of the transition phase in nova V4745 Sgr

abstract:
  We present a spectroscopic monitoring of the transient nova V4745 Sagittarii
(Nova Sgr 2003 #1) covering ten months after the discovery. During this period
the light curve showed well expressed transient phase in the form of six
rebrightenings, and the presented dataset is one of the best spectroscopic
coverages of a classical nova during the transition phase. Low- and
medium-resolution spectra revealed that the majority of spectral lines switched
back to strong P-Cyg profiles during the mini-outbursts, similar to the spectra
just after the major eruption. We interpret the observed phenomena as evidence
for ``echo-outbursts'' resulting in episodes of secondary mass-ejections and
propose that the transition phase in classical novae is driven by repetitive
instabilities of the hydrogen shell burning on the surface of the white dwarf.
  From the available light curve data we estimate the absolute magnitude of the
system of about -8.3 +/- 0.5 mag. All spectrophotometric pieces of evidence
point toward a very low (E(B-V) < 0.1) interstellar reddening, leading to a
rough distance estimate of V4745 Sgr (9 kpc < d < 19 kpc).


title: Infrared Echelle Spectroscopy of Palomar6 and M71

abstract:
  We present high-resolution infrared echelle spectroscopy for the globular
clusters Palomar 6 and M71. Our mean heliocentric radial velocity of Palomar 6
is +180.6 +/- 3.2 km sec/s and is 20 km/s lower than that found by Minniti in
1995. Contrary to the previous metallicity estimates using low-resolution
spectroscopy, our results show that Palomar~6 has an intermediate metallicity
with [Fe/H] = -1.0 +/- 0.1 and is slightly more metal-poor than M71. Reasonable
changes in the surface temperature or the microturbulent velocity of the model
atmospheres do not affect [Fe/H] at more than +/- 0.2 dex. In spite of its high
metallicity, based on the spectrum of a single cluster member the [Si/Fe] and
[Ti/Fe] ratios of Palomar~6 appear to be enhanced by 0.4 dex and 0.5 dex,
respectively, suggesting that the Galactic inner halo may have experienced a
very rapid chemical enrichment history.


title:
Centre Shift of the Raman Scattered He II $\lambda$ 4850 in the
  Symbiotic Star V1016 Cygni

abstract:
  We present our spectroscopic data around H$\beta$ of the symbiotic star V1016
Cyg obtained with the Bohyunsan Echelle Spectrograph, in order to secure the
broad emission feature at around 4850\AA, which is formed through Raman
scattering of He II $\lambda$ 972. The total cross section around Ly$\gamma$ is
approximately given by $\sigma(\lambda)\simeq 1.7\times
10^{-28}[\lambda_{Ly\gamma}/(\lambda -\lambda_{Ly\gamma})]^2{\rm cm^2}$, with
$\lambda_{Ly\gamma}$ being the line centre wavelength of Ly$\gamma$. We find a
centre shift redward by an amount $\Delta\lambda= +0.64{\rm \AA}$ in the Raman
scattered He II $\lambda$ 4850. This redward centre shift is exactly analogous
to the effect for the Raman scattered He II $\lambda$ 6545 blueward of
H$\alpha$ discussed in our previous study. We compute the branching ratios of
Raman scattering into the level $2s$ and levels $3s,$ and 3d, which are
subsequently incorporated in our Monte Carlo code. Assuming that He II
$\lambda$ 972 emission is characterized by a single Gaussian profile, the
redward peak shift observed in the Raman scattered He II 4850 feature
corresponds to the neutral column density $N_{HI}=1.2\times 10^{21}{\rm\
cm^{-2}}$. Assuming that the covering factor $\sim 0.1$ of the scattering
region with respect to the He II emission region and adopting a simple
spherical stellar wind model, we may place an upper bound $\dot M \le 3.6\times
10^{-7}{\rm M_\odot yr^{-1}}$ for the mass loss rate of the giant component of
V1016 Cyg. Our estimate can be severely affected by the inematics of the
scattering and He II emission regions and the exact atomic physics, about which
brief discussions are presented.


title: Capture and escape in the elliptic restricted three-body problem

abstract:
  Several families of irregular moons orbit the giant planets. These moons are
thought to have been captured into planetocentric orbits after straying into a
region in which the planet's gravitation dominates solar perturbations (the
Hill sphere). This mechanism requires a source of dissipation, such as
gas-drag, in order to make capture permanent. However, capture by gas-drag
requires that particles remain inside the Hill sphere long enough for
dissipation to be effective. Recently we have proposed that in the circular
restricted three-body problem particles may become caught up in `sticky'
chaotic layers which tends to prolong their sojourn within the planet's Hill
sphere thereby assisting capture. Here we show that this mechanism survives
perturbations due to the ellipticity of the planet's orbit. However, Monte
Carlo simulations indicate that the planet's ability to capture moons decreases
with increasing orbital eccentricity. At the actual Jupiter's orbital
eccentricity, this effects in approximately an order of magnitude lower capture
probability than estimated in the circular model. Eccentricities of planetary
orbits in the Solar System are moderate but this is not necessarily the case
for extrasolar planets which typically have rather eccentric orbits. Therefore,
our findings suggest that these extrasolar planets are unlikely to have
substantial populations of irregular moons.


title:
Excess of EGRET Galactic Gamma Ray Data interpreted as Dark Matter
  Annihilation

abstract:
  The diffuse galactic EGRET gamma ray data show a clear excess for energies
above 1 GeV in comparison with the expectations from conventional galactic
models. The excess is seen with the same spectrum in all sky directions, as
expected for Dark Matter (DM) annihilation. This hypothesis is investigated in
detail. The energy spectrum of the excess is used to limit the WIMP mass to the
50-100 GeV range, while the sky maps are used to determine the halo structure,
which is consistent with a triaxial isothermal halo with additional enhancement
of Dark Matter in the disc. The latter is strongly correlated with the ring of
stars around our galaxy at a distance of 14 kpc, thought to originate from the
tidal disruption of a dwarf galaxy. It is shown that this ring of DM with a
mass of $\approx 2\cdot 10^{11} M_\odot$ causes the mysterious change of slope
in the rotation curve at $R=1.1R_0$ and the large local surface density of the
disc. The total mass of the halo is determined to be $3\cdot 10^{12} M_\odot$.
A cuspy profile is definitely excluded to describe the gamma ray data. These
signals of Dark Matter Annihilation are compatible with Supersymmetry for boost
factors of 20 upwards and have a statistical significance of more than
$10\sigma$ in comparison with the conventional galactic model. The latter
combined with all features mentioned above provides an intriguing hint that the
EGRET excess is indeed a signal from Dark Matter Annihilation.


title: The Radial Distribution of Galaxies in LCDM clusters

abstract:
  We study the radial distribution of subhalos and galaxies using
high-resolution cosmological simulations of galaxy clusters formed in the
concordance LCDM cosmology. In agreement with previous studies, we find that
the radial distribution of subhalos is significantly less concentrated than
that of the dark matter, when subhalos are selected using their present-day
gravitationally bound mass. We show that the difference in the radial
distribution is not a numerical artifact and is due to tidal stripping. The
subhalos in the cluster core lose more than 70% of their initial mass since
accretion, while the average tidal mass loss for halos near the virial radius
is ~30%. This introduces a radial bias in the spatial distribution of subhalos
when they are selected using their tidally truncated mass. We demonstrate that
the radial bias disappears almost entirely if subhalos are selected using their
mass or circular velocity at the accretion epoch. The comparisons of the
results of dissipationless simulations to the observed distribution of galaxies
in clusters are therefore sensitive to the selection criteria used to select
subhalo samples. Using the simulations that include cooling and starformation,
we show that the radial distribution of subhalos is in reasonable agreement
with the observed radial distribution of galaxies in clusters for
0.1<R/R200<2.0, if subhalos are selected using the stellar mass of galaxies.
The radial bias is minimized in this case because the stars are located in the
centers of dark matter subhalos and are tightly bound. The stellar mass of an
object is therefore approximately conserved as the dark matter is stripped from
the outer regions. Nevertheless, the concentration of the radial distribution
of galaxies is systematically lower than that of the dark matter.


title: A Method For Determining Two-Dimensional Orbits In Galactic Disks

abstract:
  We propose a method for determining the two-dimensional orbits of
interstellar matter (ISM) in galactic disks using observed line-of-sight
velocity fields. Although four components, consisting of two of position and
two of velocity, are necessary to determine two-dimensional orbits, the
velocity perpendicular to the line of sight can hardly be determined from
observations. We show that the ISM orbits can be approximately determined by
assuming that (1) the angular momentum is conserved along each orbit, (2) all
orbits are closed in a single rotating frame, and (3) the system is symmetric
through the origin. Since the angular momentum can be estimated on the major
axis of a disk, a velocity perpendicular to the line of sight can be determined
according to the conservation of angular momentum, and thus two components of
velocity are obtained. The ISM orbits can be calculated by solving differential
equations given by an obtained two-dimensional velocity field when a certain
pattern speed is given. The typical deviation from the correct orbit is less
than the observational resolution according to our test calculations for
modeled velocity fields. We applied this method to the observed data of NGC
4569 and obtained possible orbits for this galaxy. Furthermore, we calculated
the mass distribution using our result.


title:
On the incidence of KHz quasi-periodic oscillations in the neutron star
  system 4U 1636-53

abstract:
  Nearly $1.32 \times 10^6$ sec of non-zero count rate data were obtained from
five years of {\rm RXTE} observations of the atoll source 4U 1636-53. The data
was divided into 10309 segments of 128 sec each. The histogram of the number of
segments as a function of count rate shows that the system can naturally be
classified into four flux states. For each segment an automated search for kHz
QPO was undertaken and the histograms of the maximum Leahy normalised power
$P_{max}$ for the four flux states were created. These were fitted by
probability distribution functions under the assumption that the intrinsic
amplitude of the QPO has a normal distribution. The best fit distribution
functions, showed that the fraction $f$ of the time the system exhibits a kHz
QPO, decreases from near unity for the lowest flux state ($\approx 1400$ c/s)
to zero for the highest one ($> 2550$ c/s) while the average amplitude remains
nearly constant. Based on the best fit probability distribution functions, a
threshold $P_{thre}$ was defined, such that 95% of the segments with $P_{max} >
P_{thre}$ correspond to a real QPO signal. For segments selected by this
criterion, the frequency versus count rate plot reproduced the earlier known
``parallel track'' variation with the tracks coinciding roughly with the flux
states. It is shown that the gaps between the tracks are not caused by uneven
sampling, but rather the QPO phenomenon is absent or weak when the system's
flux level is intermediate between two flux states.


title: Detecting and interpreting statistical lensing by absorbers

abstract:
  We propose a method for detecting gravitational magnification of distant
sources, like quasars, due to absorber systems detected in their spectra. We
first motivate the use of metal absorption lines rather than Lyman-alpha lines,
then we show how to relate the observed moments of the source magnitude
distribution to the mass distribution of absorbers. In order to illustrate the
feasibility of the method, we use a simple model to estimate the amplitude of
the effect expected for MgII absorption lines, and show that their lensing
signal might already be detectable in large surveys like the SDSS. Our model
suggests that quasars behind strong MgII absorbers are in average brightened by
-0.05 to -0.2 magnitude due to magnification. One must therefore revisit the
claim that, in magnitude limited surveys, quasars with strong absorbers tend to
be missed due to extinction effects. In addition to constraining the mass of
absorber systems, applying our method will allow for the quantification of this
bias.


title:
The Formation and Evolution of Protostellar Disks; 3D AMR
  Hydro-Simulations of Collapsing, Rotating Bonnor-Ebert-Spheres

abstract:
  We present a detailed study of the collapse of molecular cloud cores using
high resolution 3D adaptive mesh refinement (AMR) numerical simulations. In
this first in a series of investigations our initial conditions consists of
spherical molecular core obeying the hydrostatic Bonnor-Ebert-Profile with
varying degrees of initial rotation. Our simulations cover both the formation
of massive disks in which massive stars form as well as low mass disks. We use
a customized version of the FLASH code whose AMR technique allows us to follow
the formation of a protstellar disk and protostellar core(s) through more than
ten orders in density increase while continuously resolving the local Jeans
length (i.e. obeying the Truelove criterion, Truelove et al. (1997)). Our
numerical simulations also incorporate the energy loss due to molecular line
emission in order to obtain a more realistic picture of protostellar core and
disk formation. Out initial states model system of mass 168 M_sol and 2.1 M_sol
that will form high and low mass stars, respectively. We follow many features
such as the development complex shock structures, and the possible
fragmentation of the disk. We find that slowly rotating cores (Omega t_ff =
0.1) produce disks in which a strong bar develops but which does not fragment.
Faster initial rotation rates (Omega t_ff = 0.2) result in the formation of a
ring which may fragment into two star-forming cores. The size of the rings
found in our simulated disks agree with the observations of similar systems.


title:
Cosmological constraints from Gauss-Bonnet braneworld with large-field
  potentials

abstract:
  We calculate the spectral index and tensor-to-scalar ratio for patch
inflation defined by $H^2\approx \beta^2_q V^q$ and $\dot{\phi}\approx -V'/3H$,
using the slow-roll expansion. The patch cosmology arisen from the Gauss-Bonnet
braneworld consists of Gauss-Bonnet (GB), Randall-Sundrum (RS), and 4D general
relativistic (GR) cosmological models. In this work, we choose large-field
potentials of $V=V_0\phi^p$ to compare with the observational data. Since
second-order corrections are rather small in the slow-roll limit, the
leading-order calculation is sufficient to compare with the data. Finally, we
show that it is easier to discriminate between quadratic potential and quartic
potential in the GB cosmological model rather than the GR or RS cosmological
models.


title: Cosmokinetics

abstract:
  Our fundamental lack of understanding of the acceleration of the Universe
suggests that we consider a kinematic description. The simplest formalism
involves the third derivative of the scale factor through a jerk parameter. A
new approach is presented for describing the results of astronomical
observations in terms of the contemporary jerk parameter and this is related to
the equation of state approach. Simple perturbative expansions about
$\Lambda$CDM are given.


title: Nuclear Spirals as Signatures of Supermassive Black Holes

abstract:
  Recent high resolution images of spiral galaxies show wide varieties of
features including nuclear spirals in the central parts. Some of the galaxies
show grand-design nuclear spirals. The morphology of grand-design spirals can
be further divided by the openness of the arms: tightly wound ones with winding
angle of around 3$\pi$ radian and open spirals with winding angle of around
$\pi$ radian. Based on hydrodynamical simulations, we have investigated the
mechanism responsible for the openness of nuclear spirals. Since the gas flow
in the nuclear region is mainly governed by the central mass concentration near
the nuclei and the sound speed of the gas, we have examined various models with
different mass concentration represented by the mass of the central black hole
and different sound speeds. We found that the tightly wound spirals can be
formed when the mass of the black hole is large enough to remove the
inner-inner Lindblad resonances and sound speeds lie between 15 - 20 km/sec.
Thus, the presence of the tightly wound nuclear spiral could imply the presence
of relatively massive black hole in the center.


title: Random Numbers from Astronomical Imaging

abstract:
  This article describes a method to turn astronomical imaging into a random
number generator by using the positions of incident cosmic rays and hot pixels
to generate bit streams. We subject the resultant bit streams to a battery of
standard benchmark statistical tests for randomness and show that these bit
streams are statistically the same as a perfect random bit stream. Strategies
for improving and building upon this method are outlined.


title: The sub-millimetre evolution of V4334 Sgr (Sakurai's Object)

abstract:
  We report the results of monitoring of V4334 Sgr (Sakurai's Object) at 450
microns and 850 microns with SCUBA on the James Clerk Maxwell Telescope. The
flux density at both wavelengths has increased dramatically since 2001, and is
consistent with continued cooling of the dust shell in which Sakurai's Object
is still enshrouded, and which still dominates the near-infrared emission.
Assuming that the dust shell is optically thin at sub-millimetre wavelengths
and optically thick in the near-infrared, the sub-millimetre data imply a
mass-loss rate during 2003 of ~3.4(+/0.2)E-5 for a gas-to-dust ratio of 75.
This is consistent with the evidence from 1-5micron observations that the
mass-loss is steadily increasing.


title: Cold and warm dust along a merging galaxy sequence

abstract:
  We investigate the cold and warm dust properties during galaxy interactions
using a merging galaxy sample ordered into a chronological sequence from pre-
to post-mergers. Our sample comprises a total of 29 merging systems selected to
have far-infrared and sub-millimeter observations. The sub-millimeter data are
mainly culled from the literature while for 5 galaxies (NGC 3597, NGC 3690, NGC
6090, NGC 6670 and NGC 7252) the sub-millimeter observations are presented here
for the first time. We use the 100-to-850 micron flux density ratio,
f_{100}/f_{850}, as a proxy to the mass fraction of the warm and the cold dust
in these systems. We find evidence for an increase in f_{100}/f_{850} along the
merging sequence from early to advanced mergers and interpret this trend as an
increase of the warm relative to the cold dust mass. We argue that the two key
parameters affecting the f_{100}/f_{850} flux ratio is the star-formation rate
and the dust content of individual systems relative to the stars. Using a
sophisticated model for the absorption and re-emission of the stellar UV
radiation by dust we show that these parameters can indeed explain both the
increase and the observed scatter in the f_{100}/f_{850} along the merging
galaxy sequence. We also discuss our results under the hypothesis that
elliptical galaxies are formed via disc galaxy mergers.


title: On the spectroastrometric separation of binary point-source fluxes

abstract:
  Spectroastrometry is a technique which has the potential to resolve flux
distributions on scales of milliarcseconds. In this study, we examine the
application of spectroastrometry to binary point sources which are spatially
unresolved due to the observational point spread function convolution. The
technique uses measurements with sub-pixel accuracy of the position centroid of
high signal-to-noise long-slit spectrum observations. With the objects in the
binary contributing fractionally more or less at different wavelengths
(particularly across spectral lines), the variation of the position centroid
with wavelength provides some information on the spatial distribution of the
flux. We examine the width of the flux distribution in the spatial direction,
and present its relation to the ratio of the fluxes of the two components of
the binary. Measurement of three observables (total flux, position centroid and
flux distribution width) at each wavelength allows a unique separation of the
total flux into its component parts even though the angular separation of the
binary is smaller than the observations' point-spread function. This is because
we have three relevant observables for three unknowns (the two fluxes, and the
angular separation of the binary), which therefore generates a closed problem.
This is a wholly different technique than conventional deconvolution methods,
which produce information on angular sizes of the sampling scale.
Spectroastrometry can produce information on smaller scales than conventional
deconvolution, and is successful in separating fluxes in a binary object with a
separation of less than one pixel. We present an analysis of the errors
involved in making binary object spectroastrometric measurements and the
separation method, and highlight necessary observing methodology.


title:
Giant Pulses from PSR B1937+21 with widths <= 15 nanoseconds and T_b >=
  5 x 10^39 K, the Highest Brightness Temperature Observed in the Universe

abstract:
  Giant radio pulses of the millisecond pulsar B1937+21 were recorded with the
S2 VLBI system at 1.65 GHz with NASA/JPL's 70-m radio telescope at Tidbinbilla,
Australia. These pulses have been observed as strong as 65000 Jy with widths <=
15 ns, corresponding to a brightness temperature T_b >= 5 x 10^39 K, the
highest observed in the universe. The vast majority of these pulses occur in a
5.8 mcs and 8.2 mcs window at the very trailing edges of the regular main pulse
and interpulse profiles, respectively. Giant pulses occur in general with a
single spike. Only in one case out of 309 was the structure clearly more
complex. The cumulative distribution is fit by a power law with index -1.40 +/-
0.01 with a low-energy but no high-energy cutoff. We estimate that giant pulses
occur frequently but are only rarely detected. When corrected for the
directivity factor, 25 giant pulses are estimated to be generated in one
neutron star revolution alone. The intensities of the giant pulses of the main
pulses and interpulses are not correlated with each other nor with the
intensities or energies of the main pulses and interpulses themselves. Their
radiation energy density can exceed 300 times the plasma energy density at the
surface of the neutron star and can even exceed the magnetic field energy
density at that surface. We therefore do not think that the generation of giant
pulses is linked to the plasma mechanisms in the magnetosphere. Instead we
suggest that it is directly related to discharges in the polar cap region of
the pulsar.


title: HR4049: signature of nova nucleosynthesis ?

abstract:
  The post-Asymptotic Giant Branch (AGB) star HR4049 is in an eccentric binary
system with a relatively short period probably surrounded by a dusty
circumbinary disk. Extremely anomalous oxygen isotopic ratios, O16/O17 ~
O16/O18 ~ 7, have been measured from CO_2 molecules likely residing in the
disk. Such a composition cannot be explained in the framework of AGB and
post-AGB evolution while it can be qualitatively associated with the
nucleosynthesis occurring during nova outbursts. We discuss nova models, the
presence of a white dwarf companion to HR4049 and possible scenarios for the
dynamical evolution of this binary system. Circumbinary disks in which mixing
occurs between red-giant and nova material may also be invoked as the site of
formation of some rare types of meteoritic presolar grains.


title: Interaction of Jets with Galactic Winds

abstract:
  We have used the vectorised and parallelised magnetohydrodynamics code
NIRVANA on the NEC SX-5 and the new SX-6 installation in parallel mode to
simulate the interaction of jets with a galactic wind that might be typical for
the star-bursting radio-galaxies of the early universe.
  The two simulations, one axisymmetric and one in 3D show that the jet pierces
and destroys a thin and dense shell produced by the pre-installed superwind.
  We suggest that small radio galaxies at high redshift might be absorbed on
the blue wing due to the galactic wind shell, and possibly on the red wing due
to a cooling flow. In larger sources the jet cocoon will fill the wind cavity
and accelerate the shell. The Rayleigh-Taylor instability will then disrupt the
shell and disperse dense, possibly star-forming fragments throughout the
region.


title:
'Sling effect' in the development of atmospheric cascades induced by
  primary cosmic ray nuclei

abstract:
  The 'Sling effect' appears when a fragment of a projectile nucleus emitted
after its peripheral collision with a target nucleus is caused to rotate with a
high spin. The spinning fragment has a deformed shape and looks like an oblate
ellipsoid. Due to the virtual non-compressibility of nuclear matter, and the
polarization of the spin in the plane transverse to the input momentum of the
projectile nucleus such an ellipsoid has a reduced mean interaction
cross-section compared with a non-spinning fragment which has a spherical
shape. Purely geometrical arguments dictate that such an ellipsoidal nucleus
should have additional fluctuations of cross-section even at a fixed impact
parameter dependent on the orientation angle between the axis of the ellipsoid
and the vector connecting the centers of projectile and target nucleus. The
number of 'wounded nucleons' in the projectile nucleus participating in the
interaction correlates strongly with the interaction cross-section. All these
effects lead to a non-exponential attenuation of fragments and increased
probability for a fragment to penetrate down to a larger depth in the absorber,
than normal.
  If the sling effect appears in the interaction of a primary cosmic ray
nucleus with nuclei in the atmosphere the induced atmospheric cascade will have
a slower attenuation, and thereby can help to reduce some important
inconsistencies in the interpretation of the existing experimental data on
extensive air showers, observed in the lower half of the atmosphere. The paperr
gives numerical estimates of the sling effect.


title: GEMS: which galaxies dominate the z~0.7 ultraviolet luminosity density?

abstract:
  We combine high-resolution images from GEMS with redshifts and spectral
energy distributions from COMBO-17 to explore the morphological types of
galaxies that dominate the z~0.7 UV luminosity density. We analysed rest-frame
280 nm and V-band luminosities of 1483 galaxies with 0.65<z< 0.75, combining
these with visual morphological classifications from F850LP images
(approximately rest-frame V-band) taken with HST/ACS on the Extended Chandra
Deep Field South. We derive UV luminosity functions and j_280 luminosity
densities for spheroid-dominated galaxies, spiral galaxies, Magellanic
irregulars, and clearly-interacting galaxies with morphologies suggestive of
ongoing major mergers. We check the reliability of GEMS morphologies against
the deeper GOODS images and quantify an incompleteness of the GEMS merger
identification at the faint end. We derive the fractions of the global UV
luminosity density j_280 originating from the galaxy types, and find that
spiral galaxies and Magellanic irregulars dominate with about 40% each.
Interacting and merging galaxies account for roughly 20% of j_280, while the
contribution of early types is negligible. These results imply that the strong
decline in the UV luminosity density of the Universe observed from z~1 until
today is dominated by the decreasing UV luminosities of normal spiral galaxies,
accompanied by the migration of UV-luminous star formation in irregular
galaxies to systems of progressively lower mass and luminosity. (abridged)


title:
XMM-Newton observations of the Galactic Supernova Remnant CTB 109
  (G109.1-1.0)

abstract:
  We present the analysis of the X-ray Multi-Mirror Mission (XMM-Newton)
European Photon Imaging Camera (EPIC) data of the Galactic supernova remnant
(SNR) CTB 109 (G109.1-1.0). CTB 109 is associated with the anomalous X-ray
pulsar (AXP) 1E 2259+586 and has an unusual semi-circular morphology in both
the X-ray and the radio, and an extended X-ray bright interior region known as
the `Lobe'. The deep EPIC mosaic image of the remnant shows no emission towards
the west where a giant molecular cloud complex is located. No morphological
connection between the Lobe and the AXP is found. We find remarkably little
spectral variation across the remnant given the large intensity variations. All
spectra of the shell and the Lobe are well fitted by a single-temperature
non-equilibrium ionization model for a collisional plasma with solar abundances
(kT = 0.5 - 0.7 keV, tau = n_e t = 1 - 4 x 10^11 s cm^-3, N_H = 5 - 7 x 10^21
cm^-2). There is no indication of nonthermal emission in the Lobe or the shell.
We conclude that the Lobe originated from an interaction of the SNR shock wave
with an interstellar cloud. Applying the Sedov solution for the undisturbed
eastern part of the SNR, and assuming full equilibration between the electrons
and ions behind the shock front, the SNR shock velocity is derived as v_s = 720
+/- 60 km s^-1, the remnant age as t = (8.8 +/- 0.9) x 10^3 d_3 yr, the initial
energy as E_0 = (7.4 +/- 2.9) x 10^50 d_3^2.5 ergs, and the pre-shock density
of the nuclei in the ambient medium as n_0 = (0.16 +/- 0.02) d_3^-0.5 cm^-3, at
an assumed distance of D = 3.0 d_3 kpc. Assuming CTB 109 and 1E 2259+586 are
associated, these values constrain the age and the environment of the
progenitor of the SNR and the pulsar.


title:
Relativistic outflows from remnants of compact object mergers and their
  viability for short gamma-ray bursts

abstract:
  We present the first general relativistic hydrodynamic models of the launch
and evolution of relativistic jets and winds, driven by thermal energy
deposition, possibly due to neutrino-antineutrino annihilation, in the close
vicinity of black hole-accretion torus systems. The latter are considered to be
the remnants of compact object mergers. Our two-dimensional simulations
establish the link between such mergers and future observations of short
gamma-ray bursts (GRBs) by the SWIFT satellite. They show that
ultrarelativistic outflow with maximum terminal Lorentz factors (Gamma) around
1000 develops for polar energy deposition rates above some 1e48 erg/s per
steradian, provided the merger environment has a sufficiently low baryon
density. Due to the collimation by the dense accretion torus the typical
semi-opening angles of the Gamma > 100 cone are 5-10 degrees, corresponding to
about 0.4-1.5% of the hemisphere and apparent isotropized energies (kinetic
plus internal) up to ~1e51 erg. 10-30% of the deposited energy are transferred
to the outflow with Gamma > 100. Our models confirm the viability of
post-merger BH-torus systems as engines of short, hard GRBs and can explain the
durations of all observed short GRBs, because different propagation velocities
of the front and rear ends lead to a radial stretching of the ultrarelativistic
fireball before transparency is reached. The ultrarelativistic flow reveals a
highly non-uniform structure with Lorentz factor variations up to factors of a
few, caused by the action of Kelvin-Helmholtz instabilities that originate at
the fireball-torus interface (abbreviated).


title:
Microwave ISM Emission in the Green Bank Galactic Plane Survey: Evidence
  for Spinning Dust

abstract:
  We observe significant dust-correlated emission outside of H II regions in
the Green Bank Galactic Plane Survey (-4 < b < 4 degrees) at 8.35 and 14.35
GHz. The rising spectral slope rules out synchrotron and free-free emission as
majority constituents at 14 GHz, and the amplitude is at least 500 times higher
than expected thermal dust emission. When combined with the Rhodes (2.326 GHz),
and WMAP (23-94 GHz) data it is possible to fit dust-correlated emission at
2.3-94 GHz with only soft synchrotron, free-free, thermal dust, and an
additional dust-correlated component similar to Draine & Lazarian spinning
dust. The rising component generally dominates free-free and synchrotron for
\nu >~ 14 GHz and is overwhelmed by thermal dust at \nu > 60 GHz. The current
data fulfill most of the criteria laid out by Finkbeiner et al. (2002) for
detection of spinning dust.


title:
Dynamics of Line-Driven Disk Winds in Active Galactic Nuclei II: Effects
  of Disk Radiation

abstract:
  We explore consequences of a radiation driven disk wind model for mass
outflows from active galactic nuclei (AGN). We performed axisymmetric
time-dependent hydrodynamic calculations using the same computational technique
as Proga, Stone and Kallman (2000). We test the robustness of radiation
launching and acceleration of the wind for relatively unfavorable conditions.
In particular, we take into account the central engine radiation as a source of
ionizing photons but neglect its contribution to the radiation force.
Additionally, we account for the attenuation of the X-ray radiation by
computing the X-ray optical depth in the radial direction assuming that only
electron scattering contributes to the opacity. Our new simulations confirm the
main result from our previous work: the disk atmosphere can 'shield' itself
from external X-rays so that the local disk radiation can launch gas off the
disk photosphere. We also find that the local disk force suffices to accelerate
the disk wind to high velocities in the radial direction. This is true provided
the wind does not change significantly the geometry of the disk radiation by
continuum scattering and absorption processes; we discuss plausibility of this
requirement. Synthetic profiles of a typical resonance ultraviolet line
predicted by our models are consistent with observations of broad absorption
line (BAL) QSOs.


title:
Probing the IGM/Galaxy Connection Toward PKS0405-123 I: UV Spectroscopy
  and Metal-Line Systems

abstract:
  We present results from an analysis of FUSE and HST/STIS spectroscopy of the
z_em=0.57 quasar PKS0405-123. We focus on the intervening metal-line systems
identified along the sightline and investigate their ionization mechanism,
ionization state, and chemical abundances. We identify six OVI absorbers to a
3sigma equivalent width (EW) limit of 60mA. This implies an incidence dN/dz =
16^{+9}_{-6} consistent with previous OVI studies. In half of the OVI systems
we report positive detections of CIII suggesting the gas is predominantly
photoionized, has multiple ionization phases, or is in a non-equilibrium state.
This contrasts with the general description of the warm-hot intergalactic
medium (WHIM) as described by numerical simulations where the gas is
predominantly in collisional ionization equilibrium. We have also searched the
sightline for the NeVIII doublet (a better probe of WHIM gas with T>10^6K) over
the redshift range 0.2<z<z_em and report no positive detections to an EW limit
of 80mA giving dN/dz<40 at 95% c.l. The photoionized metal-line systems exhibit
a correlation between the ionization parameter (U) and HI column density for
N(HI) = 10^(14-16) cm^-2. Both the slope and normalization of this correlation
match the prediction inferred from the results of Dave and Tripp for the low z
Lya forest. In turn, the data show a tentative, unexpected result: five out of
the six photoionized metal-line systems show a total hydrogen column density
within a factor of 2 of 10^18.7 cm^-2. Finally, the median metallicity [M/H] of
twelve z~0.3 absorbers with N(HI)>10^14 cm^-2 is [M/H] ~> -1.5 with large
scatter. This significantly exceeds the median metallicity of CIV and OVI
systems at z~3 and indicates enrichment of the intergalactic medium over the
past 10Gyr. [abriged]


title:
The SMART Data Analysis Package for the Infrared Spectrograph on the
  Spitzer Space Telescope

abstract:
  SMART is a software package written in IDL to reduce and analyze Spitzer data
from all four modules of the Infrared Spectrograph, including the peak-up
arrays. The software is designed to make full use of the ancillary files
generated in the Spitzer Science Center pipeline so that it can either remove
or flag artifacts and corrupted data and maximize the signal-to-noise in the
extraction routines. It may be run in both interactive and batch mode. The
software and Users Guide will be available for public release in December 2004.
We briefly describe some of the main features of SMART including: visualization
tools for assessing the data quality, basic arithmetic operations for either
2-d images or 1-d spectra, extraction of both point and extended sources and a
suite of spectral analysis tools.


title:
Following multi-dimensional Type Ia supernova explosion models to
  homologous expansion

abstract:
  The last years have witnessed a rapid development of three-dimensional models
of Type Ia supernova explosions. Consequently, the next step is to evaluate
these models under variation of the initial parameters and to compare them with
observations. To calculate synthetic lightcurves and spectra from numerical
models, it is mandatory to follow the evolution up to homologous expansion. We
report on methods to achieve this in our current implementation of
multi-dimensional Type Ia supernova explosion models. The novel scheme is
thoroughly tested in two dimensions and a simple example of a three-dimensional
simulation is presented. We discuss to what degree the assumption of homologous
expansion is justified in these models.


title: The Double Pulsar System J0737-3039: Modulation of A by B at eclipse

abstract:
  We have investigated the eclipse of the 23-ms pulsar J0737-3039A by its 2.8-s
companion PSR J0737-3039B in the recently discovered double pulsar system using
data taken with the Green Bank Telescope at 820 MHz. We find that the pulsed
flux density at eclipse is strongly modulated with half the periodicity of the
2.8-s pulsar. The eclipse occurs earlier and is deeper at those rotational
phases of B when its magnetic axis is aligned with the line of sight than at
phases when its magnetic axis is at right angles to the line of sight. This is
consistent with the eclipse of A being due to synchrotron absorption by the
shock-heated plasma surrounding B, the asymmetry arising from the higher plasma
densities expected in the B magnetosphere's polar cusps.


title:
Interferometric Observation of the Highly Polarized SiO Maser Emission
  from the $v=1, J=5-4$ Transition Associated with VY Canis Majoris

abstract:
  We used the Submillimeter Array to image the SiO maser emission in the $v=1$,
\$J=5-4$ transition associated with the peculiar red supergiant VY Canis
Majoris. We identified seven maser components and measured their relative
positions and linear polarization properties. Five of the maser components are
coincident to within about 150 mas ($\sim$ 200 AU at the distance of 1.5 kpc);
most of them may originate in the circumstellar envelope at a radius of about
50 mas from the star along with the SiO masers in the lowest rotational
transitions. Our measurements show that two of the maser components may be
offset from the inner stellar envelope (at the 3$\sigma$ level of significance)
and may be part of a larger bipolar outflow associated with VY CMa identified
by Shinnaga et al. The strongest maser feature at a velocity of 35.9 kms$^{-1}$
has a 60 percent linear polarization, and its polarization direction is aligned
with the bipolar axis. Such a high degree of polarization suggests that maser
inversion is due to radiative pumping. Five of the other maser features have
significant linear polarization.


title: Neutron spin polarization in strong magnetic fields

abstract:
  The effects of strong magnetic fields on the inner crust of neutron stars are
investigated after taking into account the anomalous magnetic moments of
nucleons. Energy spectra and wave functions for protons and neutrons in a
uniform magnetic field are provided. The particle spin polarizations and the
yields of protons and neutrons are calculated in a free Fermi gas model.
Obvious spin polarization occurs when $B\geq10^{14}$G for protons and
$B\geq10^{17}$G for neutrons, respectively. It is shown that the neutron spin
polarization depends solely on the magnetic field strength.


title:
Unveiling the nature of the highly obscured AGN in NGC5643 with
  XMM-Newton

abstract:
  We present results from an XMM-Newton observation of the nearby Seyfert 2
galaxy NGC5643. The nucleus exhibits a very flat X-ray continuum above 2 keV,
together with a prominent K-alpha fluorescent iron line. This indicates heavy
obscuration. We measure an absorbing column density N_H in the range 6-10 x
10^{23} atoms/cm/cm, either directly covering the nuclear emission, or covering
its Compton-reflection. In the latter case, we might be observing a rather
unusual geometry for the absorber, whereby reflection from the inner far side
of a torus is in turn obscured by its near side outer atmosphere. The nuclear
emission might be then either covered by a Compton-thick absorber, or
undergoing a transient state of low activity. A second source (christened "X-1"
in this paper) at the outskirts of NGC5643 optical surface outshines the
nucleus in X-rays. If belonging to NGC5643, it is the third brightest (L_X ~ 4
x 10^{40} erg/s) known Ultra Luminous X-ray source. Comparison with past large
aperture spectra of NGC 5643 unveils dramatic X-ray spectral changes above 1
keV. We interpret them as due to variability of the active nucleus and of
source X-1 intrinsic X-ray powers by a factor >10 and 5, respectively.