title:
The Fluctuating Intergalactic Radiation Field at Redshifts z = 2.3-2.9
  from He II and H I Absorption towards HE 2347-4342

abstract:
  We provide an in-depth analysis of the He II and H I absorption in the
intergalactic medium (IGM) at redshifts z = 2.3-2.9 toward HE 2347-4342, using
spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE) and the
Ultraviolet-Visual Echelle Spectrograph (UVES) on the VLT telescope. Following
up on our earlier study (Kriss et al. 2001, Science, 293, 1112), we focus here
on two major topics: (1) small-scale variability (Delta z = 10^-3) in the ratio
eta = N(He II)/N(H I); and (2) an observed correlation of high-eta absorbers
(soft radiation fields) with voids in the (H I) Ly-alpha distribution. These
effects may reflect fluctuations in the ionizing sources on scales of 1 Mpc,
together with radiative transfer through a filamentary IGM whose opacity
variations control the penetration of 1-5 ryd radiation over 30-40 Mpc
distances. Owing to photon statistics and backgrounds, we can measure optical
depths over the ranges 0.1 < tau(HeII) < 2.3 and 0.02 < tau(HI) < 3.9, and
reliably determine values of eta = 4 tau(HeII)/tau(HI) over the range 0.1 to
460. Values of eta = 20-200 are consistent with models of photoionization by
quasars with observed spectral indices alpha_s = 0-3. Values of eta > 200 may
require additional contributions from starburst galaxies, heavily filtered
quasar radiation, or density variations. Regions with eta < 30 may indicate the
presence of local hard sources. We find that eta is higher in "void" regions,
where H I is weak or undetected and 80% of the path length has eta > 100. These
voids may be ionized by soft sources (dwarf starbursts) or by QSO radiation
softened by escape from the AGN cores or transfer through the "cosmic web". The
apparent differences in ionizing spectra may help to explain the 1.45 Gyr lag
between the reionization epochs, z(HI) = 6.2 +/-0.2 and z(HeII) = 2.8 +/-0.2.


title: Thermonuclear X-ray Bursts: Theory vs. Observations

abstract:
  I review our theoretical understanding of thermonuclear flashes on accreting
neutron stars, concentrating on comparisons to observations. Sequences of
regular Type I X-ray bursts from GS 1826-24 and 4U 1820-30 are very well
described by the theory. I discuss recent work which attempts to use the
observed burst properties in these sources to constrain the composition of the
accreted material. For GS 1826-24, variations in the burst energetics with
accretion rate indicate that the accreted material has solar metallicity; for
4U 1820-30, future observations should constrain the hydrogen fraction, testing
evolutionary models. I briefly discuss the global bursting behavior of burst
sources, which continues to be a major puzzle. Finally, I turn to superbursts,
which naturally fit into the picture as unstable carbon ignition in a thick
layer of heavy elements. I present new time-dependent models of the cooling
tails of superbursts, and discuss the various interactions between superbursts
and normal Type I bursts, and what can be learned from them.


title: Why a ring of stars at r = 20 kpc?

abstract:
  The recently discovered ring of stars near Galactocentric distance $r = 20$
kpc is interpreted as baryonic matter accreted onto the second caustic ring of
dark matter in our galaxy. Caustic rings of dark matter were predicted in the
Galactic plane at radii $a_n \simeq 40 kpc/n$ where $n=1,2,3 ..$. They can
reveal themselves by their gravitational influence on the distribution of
baryonic matter. There is additional evidence for caustic rings of dark matter
in the Milky Way from a series of sharp rises in the Galactic rotation curve.
The positions of the rises are consistent at the 3% level with the above law
for the caustic ring radii. Also, a triangular feature in the IRAS map of the
galactic plane is consistent with the imprint of the caustic ring of dark
matter nearest to us ($n=5$) upon dust and gas in the Galactic plane. These
observations imply that the dark matter in our neighborhood is dominated by a
single flow whose density and velocity vector are estimated.


title: QSO Photometric Redshift estimation for the XMM-Newton/2dF Survey

abstract:
  The technique of estimating redshifts using photometric rather than
spectroscopic observations has recently received great attention due to its
simplicity and the accuracy of the results obtained. In this work, we estimate
photometric redshifts for an X-ray selected QSO sample. This is the first time
this technique is applied on such a sample. We first calculate the accuracy of
the results obtained by comparing photometric to spectroscopic redshifts for a
sub-sample of our QSO sample: for the majority (~67%) of the objects in this
sub-sample, photometric redshift estimates are correct within Dz<0.3. We then
derive the photometric redshift distribution for the whole QSO sample. In the
future, we expect to use the photometric redshift distribution in order to
derive the distributions of properties such as the Hardness Ratio and hence the
hydrogen column density, the luminosity function etc. As an example, we
estimate here the dependence of the Hardness Ratio of the QSO sample on
photometric redshift.


title:
The local sub-mm luminosity functions and predictions from ASTRO-F/SIRTF
  to Herschel

abstract:
  We present new determinations of the local sub-mm luminosity functions. We
find the local sub-mm luminosity density converging to 7.3+/-0.2 x 10^19
W/Hz/Mpc^3 /h_65 at 850um solving the ``sub-mm Olbers' Paradox.'' Using the
sub-mm colour temperature relations from the SCUBA Local Universe Galaxy
Survey, and the discovery of excess 450um excess emission in these galaxies, we
interpolate and extrapolate the IRAS detections to make predictions of the SEDs
of all 15411 PSC-z galaxies from 50-3000um. Despite the long extrapolations we
find excellent agreement with (a) the 90um luminosity function of Serjeant et
al. (2001), (b) the 850um luminosity function of Dunne et al. (2000), (c) the
mm-wave photometry of Andreani & Franceschini (1996); (d) the asymptotic
differential and integral source count predictions at 50-3000um by
Rowan-Robinson (2001). Remarkably, the local luminosity density and the
extragalactic background light together strongly constrain the cosmic star
formation history for a wide class of evolutionary assumptions. We find that
the extragalactic background light, the 850um 8mJy source counts, and the
Omega_* constraints all independently point to a decline in the comoving star
formation rate at z>1.


title: First results from TOO observations of the Aql X-1 field with INTEGRAL

abstract:
  We present results of observations of the Aql X-1 field performed in
March-April 2003 with the INTEGRAL observatory. This TOO (Target Of
Opportunity) INTEGRAL observations was initiated upon receiving an indication
from the ASM/RXTE that the source started an outburst. Thirteen X-ray sources
were detected by the INTEGRAL imagers, JEM-X and IBIS, during these
observations. We present a preliminary spectral and timing analysis for several
bright sources in the field, Aql X-1, X1901+03, 4U1907+097, XTE J1908+094 and
X1908+075. We also detected two X-ray bursts from Aql X-1 near the end of the
general outburst episode.


title: Diagnostics of Plasma Properties in Broad Line Region of AGNs

abstract:
  The Boltzmann-plot (BPT) method for laboratory plasma diagnostic was used for
a quick estimate of physical conditions in the
  Broad Line Region (BLR) of 14 Active Galactic Nuclei (AGNs). For the BLR of
nine AGNs, where PLTE exist, the estimated electron temperature are in the
range T $\sim$ 130000K - 37000K are in good agreement with previous estimates.
The estimated electron densities depend on the opacity of the emitting plasma
in the BLR, and they are in range from $10^9\rm cm^{-3}$ (for optically thick
plasma) to $10^{14}\rm cm^{-3}$ (for optically thin plasma). Although an
alternative of PLTE in some AGNs may be very high intrinsic reddening effect,
this method may be used for fast insight into physical processes in the BLR
prior to applying more sophisticated physical models.


title: The XMM-Newton view of NGC 6251

abstract:
  We report on the nuclear X-ray properties of the radio galaxy NGC 6251
observed with XMM-Newton. NGC 6251 is a well-known radio galaxy with
intermediate FRI/II radio properties. It is optically classified as a Seyfert 2
and hosts a supermassive black hole with mass~6e8 solar masses. The 0.4-10 keV
EPIC pn continuum is best fitted by two thermal components (kT~0.5 and 1.4 keV,
respectively), plus a power law with photon index ~1.9 absorbed by a column
density NH~5e20 cm-2. We confirm the previous ASCA detection of a strong iron
line. The line, resolved in the EPIC pn spectrum, is adequately fitted with a
broad (sigma~0.6 keV) Gaussian at rest-frame energy 6.4 keV with EW 220 eV. We
also detect, for the first time, short-term, low-amplitude variability of the
nuclear flux on a timescale of a few ks. The spectral properties argue in favor
of the presence of a standard accretion disk, ruling out the base of the jet as
the sole origin of the X-rays. The moderate X-ray luminosity and lack of strong
intrinsic absorption suggest that NGC 6251 is a ``pure'' type 2 AGN which lacks
a broad-line region.


title:
Cooling of X-ray Emitting Gas by Heat Conduction in the Center of
  Cooling Flow Clusters

abstract:
  We study the possibility that a large fraction of the gas at temperatures of
\~10^7 K in cooling flow clusters cools by heat conduction to lower
temperatures, rather than by radiative cooling. We argue that this process,
when incorporated into the so-called "moderate cooling flow model", where the
effective age of the intracluster medium is much lower than the age of the
cluster, reduces substantially the expected X-ray luminosity from gas residing
at temperatures of <10^7 K. In this model, the radiative mass cooling rate of
gas at ~10^7 K inferred from X-ray observations, which is <20 % of the mass
cooling rates cited in the past, is easily met. The heat conduction is
regulated by reconnection between the magnetic field lines in cold (~10^4 K)
clouds and the field lines in the intracluster medium. A narrow conduction
front is formed, which, despite the relatively low temperature, allows
efficient heat conduction from the hot ICM to the cold clouds. The reconnection
between the field lines in cold clouds and those in the intracluster medium
occurs only when the magnetic field in the ICM is strong enough. This occurs
only in the very inner regions of cooling flow clusters, at r~10-30 kpc. The
large ratio of the number of H\alpha photons to the number of cooling hydrogen
atoms is explained by this scenario.


title: Identifying Young Brown Dwarfs Using Gravity-Sensitive Spectral Features

abstract:
  We report the initial results of the Brown Dwarf Spectroscopic Survey Gravity
Project, to study gravity sensitive features as indicators of youth in brown
dwarfs. Low-resolution (R~2000) J-band and optical (R~1000) observations using
NIRSPEC and LRIS at the W.M. Keck Observatory reveal transitions of TiO, VO, K
I, Na I, Cs I, Rb I, CaH, and FeH. By comparing these features in late-type
giants and in old field dwarfs we show that they are sensitive to the gravity
(g = GM/R^2) of the object. Using low-gravity spectral signatures as age
indicators, we observed and analyzed J-band and optical spectra of two young
brown dwarfs, G 196-3B (20-300 Myr) and KPNO Tau-4 (1-2 Myr), and two possible
low mass brown dwarfs in the sigma Orionis cluster (3-7 Myr). We report the
identification of the phi bands of TiO near 1.24 microns and the A-X band of VO
near 1.18 microns together with extremely weak J-band lines of K I in
KPNO-Tau4. This is the first detection of TiO and VO in the J-band in a
sub-stellar mass object. The optical spectrum of KPNO-Tau4 exhibits weak K I
and Na I lines, weak absorption by CaH, and strong VO bands, also signatures of
a lower gravity atmosphere. G 196-3B shows absorption features in both
wavelength regions like those of KPNO-Tau4 suggesting that its age and mass are
at the lower end of published estimates. Whereas sigma Ori 51 appears to be
consistent with a young sub-stellar object, sigma Ori 47 shows signatures of
high gravity most closely resembling an old L1.5/L0, and can not be a member of
the sigma Orionis cluster.


title:
The Distances to Open Clusters as Derived from Main-sequence Fitting.
  II. Construction of Empirically Calibrated Isochrones

abstract:
  We continue our series of papers on open cluster distances by comparing
multicolor photometry of single stars in the Hyades to theoretical isochrones
constructed with various color-temperature relations. After verifying that the
isochrone effective temperatures agree well with spectroscopically determined
values, we argue that mismatches between the photometry and the theoretical
colors likely arise from systematic errors in the color-temperature relations.
We then describe a method for empirically correcting the isochrones to match
the photometry, and discuss the dependence of the isochrone luminosity on
metallicity.


title: A search for disks around massive young stellar objects

abstract:
  We present subarcsecond observations at 2.7 and 1.4 mm of a sample of massive
young stellar objects made with the BIMA millimetre array. For most sources the
continuum emission on the smallest scales at 2.7 mm is dominated by free-free
emission from the stellar wind or jet. Strong emission at 1.4 mm shows the
presence of significant dust associated with Cep A and GL 490 but our
resolution is not sufficient to resolve any structure. The 2.7-mm emission from
GL 490 is resolved but it is not clear whether we are seeing a single
circumstellar disk or a secondary companion, although near-infrared data
support the disk hypothesis. Estimates of the dust mass yield values of ~1--4
Msun within radii of 150 to 1000 AU.


title: The Surroundings of Gamma-Ray Bursts: Constraints on Progenitors

abstract:
  The association of a supernova with a gamma-ray burst (GRB 030329) implies a
massive star progenitor, which is expected to have an environment formed by
pre-burst stellar winds. Although some sources are consistent with the expected
wind environment, many are not, being better fit by a uniform density
environment. One possibility is that this is a shocked wind, close to the burst
because of a high interstellar pressure and a low mass loss density.
Alternatively, there is more than one kind of burst progenitor, some of which
interact directly with the interstellar medium. Another proposed environment is
a pulsar wind bubble that has expanded inside a supernova, which requires that
the supernova precede the burst.


title:
Analytic solutions for spherical gravitational gas accretion on to a
  solid body

abstract:
  The process of gravitational accretion of initially homogeneous gas onto a
solid ball is studied with methods of fluid dynamics. The fluid partial
differential equations for polytropic flow can be solved exactly in an early
stage, but this solution soon becomes discontinuous and gives rise to a shock
wave. Afterwards, there is a crossover between two intermediate asymptotic
self-similar regimes, where the shock wave propagates outwards according to two
similarity laws, initially accelerating, then decelerating (and eventually
vanishing). Lastly, we study the final static state. Our purpose is to attain a
global picture of the process.


title:
SN 2003du: Signatures of the Circumstellar Environment in a Normal Type
  Ia Supernova?

abstract:
  We present observations of the Type Ia supernova 2003du and report the
detectionof an unusual, high-velocity component in the Ca II infrared triplet,
similar tofeatures previously observed in SN 2000cx and SN 2001el. This feature
exhibits a large expansion velocity (~18,000 km/s) which is nearly constant
between -7 and +2 days relative to maximum light, and disappears shortly
thereafter. Otherthan this feature, the spectral evolution and light curve
resemble those of a normal SN Ia.
  We find that the Ca II feature can plausibly be caused by a dense shell
formed when circumstellar material of solar abundance is overrun by the rapidly
expanding outermost layers of the SN ejecta. Model calculations show that the
optical and infrared spectra are remarkably unaffected by the circumstellar
interaction. In particular, no hydrogen lines are detectable in either
absorption or emission. The only qualitatively different features are the
strong, high-velocity feature in the Ca II IR-triplet, and a somewhat weaker O
I feature near 7,300 AA. The morphology and time evolution of these features
provide an estimate for the amount of accumulated matter and an indication of
the mixing in the dense shell. We apply these diagnostic tools to SN 2003du and
infer that about 2 x 10^{-2} M_sun of solar abundance material may have
accumulated in a circumstellar shell prior to the observations. Furthermore,
the early light curve data imply that the circumstellar material was originally
very close to the progenitor system, perhaps from an accretion disk, Roche lobe
or common envelope.


title: Parsec-Scale Radio Structure of the Double Active Nucleus of NGC 6240

abstract:
  NGC 6240 is a luminous infrared galaxy that, based on recent MERLIN and
CHANDRA observations, appears to host a pair of active galactic nuclei. We
present new, multiepoch and multifrequency radio observations of NGC 6240
obtained using the Very Long Baseline Array (VLBA). These observations resolve
out all of the diffuse radio continuum emission related to starburst activity
to reveal three compact sources, two associated with the infrared and X-ray
nuclei: components N1, the northern nucleus, and S, the southern nucleus; and
component S1, a weak point source lying northeast of component S. The radio
continuum properties of N1 and S both resemble those of compact radio sources
in Seyfert nuclei, including an inverted spectrum at low frequencies and high
brightness temperatures. Component N1 further resolves into a 9 pc linear
source, again resembling compact jets in some well-studied Seyfert nuclei. The
inverted radio spectrum is most likely caused by free-free absorption through
foreground plasma with emission measures of order 1E7 cm^(-6) pc, consistent
with the X-ray spectroscopy which infers the presence of a foreground, Compton
thick absorber. Synchrotron self-absorption may also contribute to the flat
spectrum of component S. Component S1 better resembles a luminous radio
supernova such as those detected in Arp 220, although we cannot specifically
rule out the possibility that S1 may be ejected material from the southern
active nucleus. We demonstrate that the light curve of S1 is at least
consistent with current radio supernova models, and, given the high
star-formation rate in the nuclear region and the (possible) proclivity of
infrared merger galaxies to produce luminous RSNe, it is not surprising that
one such supernova is detected serendipitously in the VLBA observations.


title:
Bright Lyman Break Galaxy Candidates in the Sloan Digital Sky Survey
  First Data Release

abstract:
  {Abridged} We report the discovery of six compact, starburst galaxy
candidates with redshifts 2.3 < z < 2.8 and r-band magnitudes 19.8-20.5 in the
Quasar Catalog of the Sloan Digital Sky Survey First Data Release (SDSS DR1).
The SDSS spectra of these objects resemble the composite spectrum of Lyman
Break Galaxies (LBGs) at z ~ 3 (albeit with some differences and broader
spectral lines), but the systems are 4-5 magnitudes brighter than an ``L*'' LBG
and 2-3 magnitudes brighter than the most luminous objects in typical LBG
spectroscopic surveys. These objects could be extremely luminous LBGs, normal
LBGs amplified by gravitational lensing (like MS 1512-cB58), or a rare class of
unusual BAL quasars. Under the first hypothesis, star formation rates inferred
from the UV continuum luminosities are about 300-1000 M_sun yr^-1 with no
correction for dust extinction. The SDSS images show no evidence of multiple
imaging or foreground lensing structures, but lensing amplification cannot be
ruled out with the present data. The spectra have fairly broad absorption
features and prominent high-ionization absorption, but they do not have high
ionization emission lines, nor do they resemble spectra of known BAL quasars.
Assuming that lensing and AGN contributions are unimportant, we estimate the
high end of the z ~ 2.5 galaxy luminosity function, making the crude but
conservative assumption of unit detection efficiency over our observed redshift
and magnitude range. The estimated comoving space density is above a Schechter
function extrapolation of the LBG luminosity function from fainter magnitudes.
Improved optical spectra and measurements at X-ray, IR, and sub-mm wavelengths
could help determine the nature of these remarkable objects.


title: FUSE Observation of the Ultramassive White Dwarf PG1658+441

abstract:
  We present an analysis of the Far Ultraviolet Spectroscopic Explorer (FUSE)
spectrum of the ultramassive (M = 1.31 solar mass), magnetic (B_s = 2.3 MG)
white dwarf PG 1658+441. The far ultraviolet (FUV) spectrum exhibits very broad
Lyman lines and quasi-molecular Lyman beta satellites, but weak Lyman gamma
satellites may also be present. PG 1658+441 is the hottest white dwarf known to
show these satellite features. We fit the Lyman lines with stellar models and
obtain atmospheric parameters consistent with a published analysis of the
Balmer lines. By averaging results obtained for the different FUSE segments, we
determine Teff = 29,620 +/- 500K and log g = 9.31 +/- 0.07. The models match
the data over large portions of the spectrum but discrepancies remain near the
satellite features. Finally, no trace elements have been identified in the FUV
spectrum, and we provide abundance upper limits for C, N, Si, and P.


title:
Effects of sub-mm and radio point sources on the recovery of
  Sunyaev-Zeldovich galaxy cluster parameters

abstract:
  Observations of clusters in the 30 to 350 GHz range can in principle be used
to determine a galaxy cluster's Comptonization parameter, y, peculiar velocity,
v and gas temperature, T_e via the dependence of the kinetic and thermal
Sunyaev-Zeldovich (SZ) effects on these parameters. Despite the significant
contamination expected from thermal emission by dust in high-redshift galaxies,
we find that the simultaneous determination of optical depth (tau), v and T_e
is possible from observations with sensitivity of a few uK in three or more
bands with arc minute resolution. After allowing for realistic levels of
contamination by dusty galaxies and primary CMB anisotropy, we find that
simultaneous determinations of velocities to an accuracy of better than 200
km/s and temperatures to roughly keV accuracy should be possible in the near
future. We study how errors change as a function of cluster properties (angular
core radius and gas temperature) and experimental parameters (observing time,
angular resolution and observing frequencies). Contaminating synchrotron
emission from cluster galaxies will probably not be a major contaminant of
peculiar velocity measurements.


title: Levy model for interstellar scintillations

abstract:
  Observations of radio signals from distant pulsars provide a valuable tool
for investigation of interstellar turbulence. The time-shapes of the signals
are the result of pulse broadening by the fluctuating electron density in the
interstellar medium. While the scaling of the shapes with the signal frequency
is well understood, the observed anomalous scaling with respect to the pulsar
distance has remained a puzzle for more than 30 years. We propose a new model
for interstellar electron density fluctuations, which explains the observed
scaling relations. We suggest that these fluctuations obey Levy statistics
rather than Gaussian statistics, as assumed in previous treatments of
interstellar scintillations.


title: On the origin of brown dwarfs and free-floating planetary mass objects

abstract:
  (abridged) Sub-stellar mass objects have fundamentally different binary
properties than stars implying that they cannot have the same formation
history. They are rather unfinished stars having either been ejected by their
siblings from compact groups of accreting hydrostatic cores, or having lost
their accretion envelopes through photo-evaporation by nearby O stars or
through hyperbolic encounters with other accreting cores in their birth
clusters. All three scenarios are studied with a view to understanding the
observed smaller number of brown dwarfs (BDs) per star in the Taurus
star-forming region as opposed to the larger number of BDs per star seen in the
Orion Nebula cluster. It is found that both environments can produce the same
number of ejected BDs per star if the true production rate is about one BD per
four stars and the ejection velocity is about 2 km/s. This production rate is
much lower than the number of BDs per star inferred for the Galactic field.
Adding photo-evaporated and collisional BDs cannot reconcile this difference.
The only possible solution would be to postulate that tranquil star-formation
such as in Taurus is producing about one BD per star with ejection velocities
of about 3 km/s, while Orion-Nebula-type clusters produce at most about one BD
per three stars. Unless the Galactic-field census of BDs has been
overestimated, this then would imply that low-mass star-forming regions may be
the primary source of the field BDs, rather than rich clusters.


title: The Clustering of Intergalactic Metals

abstract:
  We measure the spatial clustering of metals in the intergalactic medium from
z = 1.7 to 3.0, as traced by 643 CIV and 104 SiIV N >= 10^12 cm^-2 absorption
systems in 19 high signal-to-noise (40-80) and high resolution (R = 45000)
quasar spectra. The number densities and two-point correlation functions of
both these species are largely constant with redshift, suggesting the bulk of
metal ejection occurred at z >= 3. However, at z <= 1.9 some additional
signature appears in the CIV correlation function at 500 km/s, associated with
four strong and peculiar systems. At all redshifts, the CIV and SiIV
correlation functions exhibit a steep rise at large separations and a flatter
profile at small separations, with an elbow occurring at ~150 km/s. We show
that these properties are consistent with metals confined within bubbles with a
typical radius R_s about sources of mass >= M_s, and use numerical simulations
to derive best-fit values of R_s ~ 2 comoving Mpc and M_s ~ 5x10^11 solar
masses at z = 3. This does not exclude that metals could have been produced at
higher redshifts in smaller, but equally rare, objects. At the level of
detection of this survey, IGM enrichment is likely to be incomplete and
inhomogeneous, with a filling factor ~ 10%.


title: Hydra A at Low Radio Frequencies

abstract:
  We present new, low-frequency images of the powerful FR I radio galaxy Hydra
A (3C 218). Images were made with the Very Large Array (VLA) at frequencies of
1415, 330, and 74 MHz, with resolutions on the order of 20". The morphology of
the source is seen to be more complex and even larger than previously known,
and extends nearly 8' (530 kpc) in a North-South direction. The southern lobe
is bent to the east and extends in that direction for nearly 3' (200 kpc). In
addition, we find that the northern lobe has a flatter spectral slope than the
southern lobe, consistent with the appearance of greater confinement to the
south. We measure overall spectral indices \alpha^{330}_{74} = -0.83 and
\alpha^{1415}_{330} = -0.89.


title: Multicolour observations of V404 Cyg with ULTRACAM

abstract:
  We present high time-resolution multicolour observations of the quiescent
soft X-ray transient V404 Cyg obtained with ULTRACAM. Superimposed on the
secondary star's ellipsoidal modulation are large flares on timescales of a few
hours, as well as several distinct rapid flares on timescales of tens of mins.
The rapid flares, most of which show further variability and unresolved peaks,
cover shorter timescales than those reported in previous observations. The
power density spectrum (PDS) of the 5 s time-resolution data shows a
quasi-periodic oscillation (QPO) feature at 0.78 mHz (=21.5 min). Assuming this
periodicity represents the Keplerian period at the transition between the thin
and advective disc regions, we determine the transition radius. We discuss the
possible origins for the QPO feature in the context of the advection-dominated
accretion flow model.
  We determine the colour of the large flares and find that the i' band flux
per unit frequency interval is larger than that in the g' band. The colour is
consistent with optically thin gas with a temperature of ~8000 K arising from a
region with an equivalent blackbody radius of at least 2 Ro, which covers 3
percent of the accretion disc's surface. Our timing and spectral analysis
results support the idea that the rapid flares (i.e. the QPO feature) most
likely arise from regions near the transition radius.


title:
Radio and Far-Infrared Emission as Tracers of Star Formation and AGN in
  Nearby Cluster Galaxies

abstract:
  We have studied the radio and far-infrared (FIR) emission from 114 galaxies
in the 7 nearest clusters (<100 Mpc) with prominent X-ray emission to
investigate the impact of the cluster environment on the star formation and AGN
activity in the member galaxies. The X-ray selection criterion is adopted to
focus on the most massive and dynamically relaxed clusters. A large majority of
cluster galaxies show an excess in radio emission over that predicted from the
radio-FIR correlation, the fraction of sources with radio excess increases
toward cluster cores, and the radial gradient in the FIR/radio flux ratio is a
result of radio enhancement. Of the radio-excess sources, 70% are early-type
galaxies and the same fraction host an AGN. The galaxy density drops by a
factor of 10 from the composite cluster center out to 1.5 Mpc, yet galaxies
show no change in FIR properties over this region, and show no indication of
mass segregation. We have examined in detail the physical mechanisms that might
impact the FIR and radio emission of cluster galaxies. While collisional
heating of dust may be important for galaxies in cluster centers, it appears to
have a negligible effect on the observed FIR emission for our sample galaxies.
The correlations between radio and FIR luminosity and radius could be explained
by magnetic compression from thermal ICM pressure. We also find that simple
delayed harassment cannot fully account for the observed radio, FIR, and mid-IR
properties of cluster galaxies.


title: Multiepoch Sky Surveys and the Lifetime of Quasars

abstract:
  We present a new method to measure the episodic lifetime of quasars with
current and future large-scale sky surveys. Future photometric observations of
large samples of confirmed quasars can provide a direct measurement (or
interesting lower limit) to the lifetime of an individual episode of quasar
activity (t_Q) and potentially enable the study of post-quasar host galaxies.
Photometric observations of the quasars found by the Sloan Digital Sky Survey
(SDSS) and 2dF Survey could, with a time baseline of ten years, determine t_Q
to within a factor of two if t_Q < 10^5 years, or set a lower limit to the
quasar lifetime. Multiple-epoch, precise photometry with the proposed Large
Synoptic Survey Telescope could test more complex models for quasar variability
and mean quasar luminosity evolution. These observations could also constrain
the rate that tidal disruptions of single stars produce quasar luminosities.
  It is possible to reverse the order of this investigation; previous-epoch
plate material, such as the Digitized Sky Survey, can be used to determine if
any of the SDSS quasars had not yet turned on at the time of these prior
observations. Measurements of the entire SDSS quasar sample over the ~50 year
baseline provided by these plates can potentially be used to estimate t_Q to
within a factor of two if t_Q < 10^{5.5} years, provided quasar variability can
be accurately characterized and the detection efficiency and photometric
calibration of the plate material can be well determined. These measurements of
t_Q will have comparable quality to existing, more indirect estimates of the
quasar lifetime. Analysis of the 3814 quasars in the SDSS Early Data Release
finds that t_Q must be larger than approximately 20,000 years.


title: Interstellar Atomic Abundances

abstract:
  A broad array of interstellar absorption features that appear in the
ultraviolet spectra of bright sources allows us to measure the abundances and
ionization states of many important heavy elements that exist as free atoms in
the interstellar medium. By comparing these abundances with reference values in
the Sun, we find that some elements have abundances relative to hydrogen that
are approximately consistent with their respective solar values, while others
are depleted by factors that range from a few up to around 1000. These
depletions are caused by the atoms condensing into solid form onto dust grains.
Their strengths are governed by the volatility of compounds that are produced,
together with the densities and velocities of the gas clouds. We may
characterize the depletion trends in terms of a limited set of parameters; ones
derived here are based on measurements of 15 elements toward 144 stars with
known values of N(H I) and N(H2). In turn, these parameters may be applied to
studies of the production, destruction, and composition of the dust grains. The
interpretations must be done with care, however, since in some cases deviations
from the classical assumptions about missing atoms in unseen ionization stages
can create significant errors. Our experience with the disk of our Galaxy
offers important lessons for properly unravelling results for more distant
systems, such as high- and intermediate-velocity clouds in the Galactic halo,
material in the Magellanic Stream and Magellanic Clouds, and otherwise
invisible gas systems at large redshifts (detected by absorption features in
quasar spectra). Inferences about the total (gas plus dust) abundances of such
systems offer meaningful information on their origins and/or chemical
evolution.


title: WIMP matter power spectra and small scale power generation

abstract:
  Dark Matter (DM) is generally assumed to be massive, cold and collisionless
from the structure formation point of view. A more correct statement however is
that DM indeed experiences collisional damping, but on a scale which is
supposed to be too small to be relevant for structure formation. The aim of
this paper is to present a Cold (although ``collisional'') Dark Matter particle
whose matter power spectrum is damped and see whether it is distinguishable
from standard candidates. To achieve this purpose, we calculate the collisional
damping and free-streaming scales of neutralinos and non conventional
candidates (say light particles heavier than ~1 MeV but lighter than O(10)
GeV). The latter can be considered as Cold Dark Matter (CDM) particles in the
sense that they become non relativistic before their thermal decoupling epoch.
Unlike neutralinos, however, their linear matter power spectrum can be damped
on scales of ~ 10^3 Msol due to their interactions. Since these scales are of
cosmological interest for structure formation, we perform a series of numerical
simulations to obtain the corresponding non linear matter power spectra
P(k)_{nl} at the present epoch. We show that because of small scale
regeneration, they all resemble each other at low redshifts, i.e. become very
similar to a typical CDM matter power spectrum on all but the smallest scales.
Therefore, even if lensing measurements at redshift below unity were to yield a
P(k)_{nl} consistent with CDM models, this would not constitute a sufficiently
robust evidence in favour of the neutralino to rule out alternative DM
candidates.


title: Propane on Titan

abstract:
  We present the first observations of propane (C$_3$H$_8$) on Titan that
unambiguously resolve propane features from other numerous stratospheric
emissions. This is accomplished using a $R=\lambda/\delta\lambda\approx10^5$
spectrometer (TEXES) to observe propane's $\nu_{26}$ rotation-vibration band
near 748 cm$^{-1}$. We find a best-fit fractional abundance of propane in
Titan's stratosphere of $(6.2\pm1.2)\times10^{-7}$ in the altitude range to
which we are sensitive (90-250 km or 13-0.24 mbar).


title: Instability of the 13.8 day period in X-ray emission from 4U1700-377

abstract:
  We present a new result on long-term periodicity searches of the X-ray
emission from 4U1700-377 using RXTE ASM and CGRO BATSE data. The hard X-ray
data (20 - 200 keV) from early BATSE observations (1780 days from JD 2448370,
before RXTE observations started) show evidence of a 13.8 day periodicity. The
long term periodicity became substantially less prominent in the data from
later BATSE observations and in the soft X-ray data from the ASM (2 - 10 keV)
observations. We demonstrate that disk precession models can explain the 13.8
day period and its instability in the X-ray emission from 4U1700-377.


title:
Subaru Deep Survey V. A Census of Lyman Break Galaxies at z=4 and 5 in
  the Subaru Deep Fields: Photometric Properties

abstract:
  (abridged) We investigate photometric properties of Lyman Break Galaxies
(LBGs) at z=3.5-5.2 based on large samples of 2,600 LBGs detected in deep
(i'~27) and wide-field (1,200 arcmin^2) images taken in the Subaru Deep Field
(SDF) and the Subaru/XMM Deep Field (SXDF). The selection criteria for the LBG
samples are examined with 85 spectroscopically identified objects and by Monte
Carlo simulations. We find in the luminosity functions of LBGs (i) that the
number density of bright galaxies (M_{1700}<-22; corresponding to
SFR_{corr}>100 Msolar yr^{-1}) decreases significantly from z=4 to 5 and (ii)
that the faint-end slope of the luminosity function may become steeper towards
higher redshifts. We estimate dust extinction of z=4 LBGs with M<M^* from UV
slopes, and obtain E(B-V)=0.15+/-0.03 as the mean value. The dust extinction
remains constant with apparent luminosity, but increases with intrinsic
luminosity. We find no evolution in dust extinction between LBGs at z=3 and 4.
We investigate the evolution of UV-luminosity density at 1700A, rho, and find
that rho does not significantly change from z=3 to z=5, i.e.,
rho(z=4)/rho(z=3)=1.0+/-0.2 and rho(z=5)/rho(z=3)=0.8+/-0.4, thus the cosmic
star-formation rate (SFR) density remains constant. We find that the stellar
mass density estimated from the cosmic SFR is consistent with those derived
directly from the stellar mass function at z=0-1, but exceeds those at z~3 by a
factor of 3. We find that the ratio of the UV-luminosity density of Ly-a
emitters (LAEs) to that of LBGs is ~60% at z=5, and thus about a half of the
star formation at z=5 probably occurs in LAEs. We obtain a constraint on the
escape fraction of UV-ionizing photons produced by LBGs, f_{esc}>~0.13.


title: FORTE satellite constraints on ultra-high energy cosmic particle fluxes

abstract:
  The FORTE (Fast On-orbit Recording of Transient Events) satellite records
bursts of electromagnetic waves arising from near the Earth's surface in the
radio frequency (RF) range of 30 to 300 MHz with a dual polarization antenna.
We investigate the possible RF signature of ultra-high energy cosmic-ray
particles in the form of coherent Cherenkov radiation from cascades in ice. We
calculate the sensitivity of the FORTE satellite to ultra-high energy (UHE)
neutrino fluxes at different energies beyond the Greisen-Zatsepin-Kuzmin (GZK)
cutoff. Some constraints on supersymmetry model parameters are also estimated
due to the limits that FORTE sets on the UHE neutralino flux. The FORTE
database consists of over 4 million recorded events to date, including in
principle some events associated with UHE neutrinos. We search for candidate
FORTE events in the period from September 1997 to December 1999. The candidate
production mechanism is via coherent VHF radiation from a UHE neutrino shower
in the Greenland ice sheet. We demonstrate a high efficiency for selection
against lightning and anthropogenic backgrounds. A single candidate out of
several thousand raw triggers survives all cuts, and we set limits on the
corresponding particle fluxes assuming this event represents our background
level.


title:
Subaru Deep Survey VI. A Census of Lyman Break Galaxies at z=4 and 5 in
  the Subaru Deep Fields: Clustering Properties

abstract:
  We investigate the clustering properties of 2,600 Lyman Break Galaxies (LBGs)
at z=3.5-5.2 in two large blank fields, the Subaru Deep Field and the
Subaru/XMM Deep Field (600arcmin^2 each). The angular correlation functions of
these LBGs show a clear clustering at both z~4 and 5. The correlation lengths
are r_0= 4.1^{+0.2}_{-0.2} and 5.9^{+1.3}_{-1.7} h_{100}^{-1} Mpc (r_0=
5.1^{+1.0}_{-1.1} and 5.9^{+1.3}_{-1.7} h_{100}^{-1} Mpc) for all the detected
LBGs (for L>L* LBGs) at z~4 and 5, respectively. These correlation lengths
correspond to galaxy-dark matter biases of b_g= 2.9^{+0.1}_{-0.1} and
4.6^{+0.9}_{-1.2} (b_g=3.5^{+0.6}_{-0.7} and 4.6^{+0.9}_{-1.2}), for all the
detected LBGs (for L>L^* LBGs) at z~4 and 5, respectively. These results,
combined with estimates for z~3 LBGs in the literature, show that the
correlation length of L>L^* LBGs is almost constant, ~5 h_{100}^{-1} Mpc, over
z~3-5, while the bias monotonically increases with redshift at z>3. We also
find that for LBGs at z~4 the clustering amplitude increases with UV-continuum
luminosity and with the amount of dust extinction. We estimate the mass of dark
halos hosting various kinds of high-z galaxies including LBGs with the analytic
model given by Sheth & Tormen (1999). We find that the typical mass of dark
halos hosting L>L^* LBGs is about 1x10^{12} h_{70}^{-1}Msol over z~3-5, which
is comparable to that of the Milky Way Galaxy. A single dark halo with ~10^{12}
h_{70}^{-1} Msol is found to host 0.1-0.3 LBG on average but host about four
K-band selected galaxies.


title: On the Bottom Magnetic Fields of the Millisecond Pulsars

abstract:
  The magnetic field strengths of most millisecond pulsars(MSP) are about
$10^{8-9}$ Gauss. The accretion induced magnetic field evolution scenario here
concludes that the field decay is invesely related to the accreted mass and the
minimum field or bottom field stops at about $10^{8}$ Gauss if accreted with
the Eddington accretion rate, which is proportionally related with the
accretion rate as $\dot{M}^{1/2}$. The possibility of the low field $\sim
10^{7}$ Gauss MSPs has been proposed for the future radio observation.


title:
Large-Field Multicolor Study of Abell 168 : Subclusters, Dynamics and
  Luminosity Functions

abstract:
  This paper presents a multicolor study of the nearby cluster of galaxies
Abell 168 (z=0.045) with 13 intermediate-band filters in the
Beijing-Arizona-Taiwan-Connecticut (BATC) filter system. After a
cross-identification between the photometric data obtained from the BATC and
the Sloan Digital Sky Survey (SDSS), a catalog containing 1553 galaxies down to
r'<20.0 mag is achieved, which includes 121 spectroscopically confirmed member
galaxies. The technique of photometric redshift has been applied to all these
galaxies with combined 18-band (13 from BATC and 5 from SDSS) spectral energy
distributions (SEDs), in order to perform a faint membership selection in Abell
168. As a result, 255 galaxies are newly selected as the member candidates.
  Based on the enlarged sample of cluster galaxies, the spatial distribution
and dynamics of Abell 168 are investigated. In the light of the spatial
distribution of the member galaxies and the 0.2-3.5 keV X-ray image by Einstein
observatory, it seems that Abell 168 consists of two merging subclusters with a
relative radial velocity of 264 +/- 142 km/s. With the help of ROSTAT software,
a detailed investigation of the dynamics shows the intrinsic difference in the
velocity distributions for these two subclusters. Under a linear two-body
model, they are found to be a gravitationally bound system with 92%
probability. The slight deviation of the local velocity distribution from the
overall distribution in the central region may suggest a picture of head-on
collision in the projection plane. By using a double Schechter function, the
close examination of the luminosity functions reveals the different galaxy
content of these two subclusters, which implies the merging process is possibly
at the early stage.


title:
Incorporation of cosmic ray transport into the ZEUS MHD code.
  Application for studies of Parker instability in the ISM

abstract:
  We present a numerical algorithm for the incorporation of the active cosmic
ray transport, into the ZEUS-3D magnetohydrodynamical code. The cosmic ray
transport is described by the diffusion-advection equation. The applied form of
the diffusion tensor allows for anisotropic diffusion of cosmic rays along and
across the magnetic field direction, which is controlled by two parameters: the
parallel and perpendicular diffusion coefficients. The implemented numerical
algorithm is tested by comparison of the diffusive transport of cosmic rays to
analytical solutions of the diffusion equation. Our method is numerically
stable for a wide range of diffusion coefficients, including the realistic
values inferred from the observational data for the Milky Way of about $ 6
\times 10^{28} \cm^2 \s^{-1}$. The presented algorithm is applied for exemplary
simulations of the the Parker instability triggered by cosmic rays injected by
a single SN remnant.


title:
Giant Meterwave Radio Telescope observations of an M2.8 flare: insights
  into the initiation of a flare-coronal mass ejection event

abstract:
  We present the first observations of a solar flare with the GMRT. An M2.8
flare observed at 1060 MHz with the GMRT on Nov 17 2001 was associated with a
prominence eruption observed at 17 GHz by the Nobeyama radioheliograph and the
initiation of a fast partial halo CME observed with the LASCO C2 coronograph.
Towards the start of the eruption, we find evidence for reconnection above the
prominence. Subsequently, we find evidence for rapid growth of a vertical
current sheet below the erupting arcade, which is accompanied by the flare and
prominence eruption.


title:
Reconstructing the Primordial Spectrum from WMAP Data by the Cosmic
  Inversion Method

abstract:
  We reconstruct the primordial spectrum of the curvature perturbation, $P(k)$,
from the observational data of the Wilkinson Microwave Anisotropy Probe (WMAP)
by the cosmic inversion method developed recently. In contrast to conventional
parameter-fitting methods, our method can potentially reproduce small features
in $P(k)$ with good accuracy. As a result, we obtain a complicated oscillatory
$P(k)$. We confirm that this reconstructed $P(k)$ recovers the WMAP angular
power spectrum with resolution up to $\Delta \ell \simeq 5$. Similar
oscillatory features are found, however, in simulations using artificial cosmic
microwave background data generated from a scale-invariant $P(k)$ with random
errors that mimic observation. In order to examine the statistical significance
of the nontrivial features, including the oscillatory behaviors, therefore, we
consider a method to quantify the deviation from scale-invariance and apply it
to the $P(k)$ reconstructed from the WMAP data. We find that there are possible
deviations from scale-invariance around $k \simeq 1.5\times10^{-2}$ and
$2.6\times10^{-2}{\rm Mpc}^{-1}$.


title: First detections of extragalactic SO2, NS and NO

abstract:
  We report the first detections of SO_2, NS and NO in an extragalactic source,
the nucleus of the starburst galaxy NGC 253. Five SO_2 transitions, three
groups of hyperfine components of NO and five of NS were detected. All three
species show large abundances averaged over the inner 200 pc of NGC 253. With a
relative abundance of a few 10^-7, the emission of the NO molecule is similar
or even larger than that found in Galactic star forming regions. The derived
relative molecular abundances for each molecule have been compared with those
of prototypical Galactic molecular clouds. These results seem to confirm that
large scale shocks dominate the chemistry of these molecules in the nucleus of
NGC 253, ruling out a chemistry dominated by PDRs for the bulk of the gas.


title:
The regeneration of stellar bars by tidal interactions. Numerical
  simulations of fly-by encounters

abstract:
  We study the regeneration of stellar bars triggered by a tidal interaction,
using numerical simulations of either purely stellar or stellar+gas disc
galaxies. We find that interactions which are sufficiently strong to regenerate
the bar in the purely stellar models do not lead to a regeneration in the
dissipative models, owing to the induced gas inflow in those models. In models
in which the bar can be regenerated, we find a tight correlation between the
strength and the pattern speed of the induced bar. This relation can be
explained by a significant radial redistribution of angular momentum in the
disc due to the interaction, similar to the processes and correlations found
for isolated barred spirals. We furthermore show that the regenerated bars show
the same dynamical properties as their isolated counterparts.


title: Supernova 2002bo: inadequacy of the single parameter description

abstract:
  We present optical/near-infrared photometry and spectra of the type Ia SN
2002bo spanning epochs from -13 days before maximum B-band light to +102 days
after. The pre-maximum optical coverage is particularly complete. In some
respects, SN 2002bo behaves as a typical "Branch normal" type Ia supernova (SN
Ia) at optical and IR wavelengths. We find a B-band risetime of 17.9+-0.5 days,
a Dm_{15}(B) of 1.13+-0.05, and a M_B=-19.41+-0.42. However, comparison with
other type Ia supernovae having similar Delta m_{15}(B) values indicates that
in other respects SN 2002bo is unusual. While the optical spectra of SN 2002bo
are very similar to those of SN 1984A, lower velocities and a generally more
structured appearance are found in SNe 1990N, 1994D and 1998bu. For supernovae
having Dm_(15)(B) > 1.2, we confirm the variation of R(SiII) (Nugent et al.
1995) with Dm_(15)(B). However, for supernovae such as SN2002bo, with lower
values of Dm_(15)(B) the relation breaks down. Moreover, the evolution of
R(SiII) for SN 2002bo is strikingly different from that shown by other type Ia
supernovae. The velocities of SN 2002bo and 1984A derived from SII 5640A, SiII
6355A and CaII H&K lines are either much higher and/or evolve differently from
those seen in other normal SNe Ia events. We suggest that the unusually low
temperature, the presence of high-velocity intermediate-mass elements and the
low abundance of carbon at early times indicates that burning to Si penetrated
to much higher layers than in more normal type Ia supernovae. This may be
indicative of a delayed-detonation explosion.


title:
Non-local effects in the mean-field disc dynamo. I. An asymptotic
  expansion

abstract:
  We reconsider thin-disc global asymptotics for kinematic, axisymmetric
mean-field dynamos with vacuum boundary conditions. Non-local terms arising
from a small but finite radial field component at the disc surface are
consistently taken into account for quadrupole modes. As in earlier approaches,
the solution splits into a local part describing the field distribution along
the vertical direction and a radial part describing the radial (global)
variation of the eigenfunction. However, the radial part of the eigenfunction
is now governed by an integro-differential equation whose kernel has a weak
(logarithmic) singularity. The integral term arises from non-local interactions
of magnetic fields at different radii through vacuum outside the disc. The
non-local interaction can have a stronger effect on the solution than the local
radial diffusion in a thin disc, however the effect of the integral term is
still qualitatively similar to magnetic diffusion.


title:
Non-local effects in the mean-field disc dynamo. II. Numerical and
  asymptotic solutions

abstract:
  The thin-disc global asymptotics are discussed for axisymmetric mean-field
dynamos with vacuum boundary conditions allowing for non-local terms arising
from a finite radial component of the mean magnetic field at the disc surface.
This leads to an integro-differential operator in the equation for the radial
distribution of the mean magnetic field strength, $Q(r)$ in the disc plane at a
distance $r$ from its centre; an asymptotic form of its solution at large
distances from the dynamo active region is obtained. Numerical solutions of the
integro-differential equation confirm that the non-local effects act similarly
to an enhanced magnetic diffusion. This leads to a wider radial distribution of
the eigensolution and faster propagation of magnetic fronts, compared to
solutions with the radial surface field neglected. Another result of non-local
effects is a slowly decaying algebraic tail of the eigenfunctions outside the
dynamo active region, $Q(r)\sim r^{-4}$, which is shown to persist in nonlinear
solutions where $\alpha$-quenching is included. The non-local nature of the
solutions can affect the radial profile of the regular magnetic field in spiral
galaxies and accretion discs at large distances from the centre.


title:
In Search of Evidence for Toroidal B Fields Associated with the Jets of
  AGN

abstract:
  Evidence is mounting that many of the transverse jet B fields observed in BL
Lac objects on parsec scales represent the dominant toroidal component of the
intrinsic jet B fields. If this is the case, this may give rise to
rotation-measure (RM) gradients across the jets, due to the systematic change
in the line-of-sight component of the jet B field. We have found evidence for
such RM gradients in several BL Lac objects. We discuss these new results,
together with some of their implications for our understanding of the pc-scale
jets of AGN.


title: A Time-Dependent Model of HD209458b

abstract:
  We developed a time-dependent radiative model for the atmosphere of HD209458b
to investigate its thermal structure and chemical composition. Time-dependent
temperature profiles were calculated, using a uniform zonal wind modelled as a
solid body rotation. We predict day/night temperature variations of 600K around
0.1 bar, for a 1 km/s wind velocity, in good agreement with the predictions by
Showman & Guillot (2002). On the night side, the low temperature allows the
sodium to condense. Depletion of sodium in the morning limb may explain the
lower than expected abundance found by Charbonneau et al (2002).


title: Cosmological consequences of an inhomogeneous space-time

abstract:
  Astrophysical observations provide a picture of the universe as a 4-dim
homogeneous and isotropic flat space-time dominated by an unknown form of dark
energy. To achieve such a cosmology one has to consider in the early universe
an inflationary era able to overcome problems of standard cosmological models.
Here an inhomogeneous model is proposed which allows to obtain a
Friedmann-Robertson-Walker behaviour far away from the inhomogeneities and it
naturally describes structures formation. We also obtain that the cosmological
term does not prevent structure formation, avoiding a fine tuning problem in
initial conditions. The asymptotic exact solution have been calculated. A
simple test with universe age prediction has been performed. A relation between
the inhomogeneity, the breaking of time reversal, parity and the
matter-antimatter asymmetry is briefly discussed.


title:
N-body simulations for coupled dark energy: halo mass function and
  density profiles

abstract:
  We present the results of a series of N-body simulations in cosmologies where
dark matter (DM) is coupled to dark energy (DE), so easing the cosmic
coincidence problem. The dark-dark coupling introduces two novel effects in
N-body dynamics: (i) DM particle masses vary with time; (ii) gravity between DM
particles is ruled by a constant $G^{*}$, greater than Newton's constant $G$,
holding in other 2-body interactions. As a consequence, baryons and DM particle
distributions develop a large scale bias. Here we investigate DE models with
Ratra-Peebles (RP) potentials; the dark-dark coupling is set in a parametric
range compatible with observations, for as concern background and linear
perturbation properties. We study the halo mass function, the halo density
profile and the behavior of the non-linear bias. We find that non-linear
dynamics puts additional constraints to the coupling parameter. They mostly
arise from density profiles, that we find to yield higher concentrations, in
coupled RP models, with respect to (uncoupled) dynamical DE cosmologies. Such
enhancement, although being a strong effect in some coupling parameter range,
is just a minor change for smaller but significant values of the coupling
parameter. With these further restrictions, coupled DE models with RP potential
are consistent with non-linear observables.


title:
Stellar evolution with rotation and magnetic fields:I. The relative
  importance of rotational and magnetic effects

abstract:
  We compare the current effects of rotation in stellar evolution to those of
the magnetic field created by the Tayler instability. In stellar regions, where
magnetic field can be generated by the dynamo due to differential rotation
(Spruit 2002), we find that the growth rate of the magnetic instability is much
faster than for the thermal instability. Thus, meridional circulation is
negligible with respect to the magnetic fields, both for the transport of
angular momentum and of chemical elements. Also, the horizontal coupling by the
magnetic field, which reaches values of a few $10^5$ G, is much more important
than the effects of the horizontal turbulence. The field, however, is not
sufficient to distort the shape of the equipotentials. We impose the condition
that the energy of the magnetic field created by the Tayler--Spruit dynamo
cannot be larger than the energy excess present in the differential rotation.
This leads to a criterion for the existence of the magnetic field in stellar
interiors. Numerical tests are made in a rotating star model of 15 M$_{\odot}$
rotating with an initial velocity of 300 km$\cdot$s$^{-1}$.


title:
On the Contribution of Gamma Ray Bursts to the Galactic Inventory of
  Some Intermediate Mass Nuclei

abstract:
  Light curves from a growing number of Gamma Ray Bursts (GRBs) indicate that
GRBs copiously produce radioactive Ni moving outward at fractions of the speed
of light. We calculate nuclear abundances of elements accompanying the
outflowing Ni under the assumption that this Ni originates from a wind blown
off of a viscous accretion disk. We also show that GRB's likely contribute
appreciably to the galactic inventory of 42Ca, 45Sc, 46Ti, 49Ti, 63Cu, and may
be a principal site for the production of 64Zn.


title: Extended Red Emission: Photoluminescence by Interstellar Nanoparticles

abstract:
  Interstellar dust in nebulae and in the diffuse interstellar medium of
galaxies contains a component which responds to illumination by ultraviolet
photons with efficient luminescence in the 500 nm to 1000 nm spectral range,
known as Extended Red Emission (ERE). We review the techniques of detection and
the observational characteristics of the ERE in a wide range of astrophysical
environments. We then discuss results of the analysis of ERE observations,
leading to a set of specific constraints that any proposal for the ERE carrier
must confront. Finally, we review specific models that have been advanced over
the past two decades to explain the ERE phenomenon. Despite promising progress
on several fronts, no completely satisfactory model for the ERE carrier/process
exists at this time.


title: Proto-clusters associated with radio galaxies from z = 2 to z = 4

abstract:
  We have carried out narrow band imaging targeted at the Lya line of emitters
associated with radio galaxies at 2 < z < 5. Subsequent spectroscopy has
confirmed the identity of > 120 Lya emitters and led to the discovery of six
proto-clusters up to z = 4.1 with velocity dispersions between 300 and 1000
km/s. The number of emission line galaxies in the observed fields is four to
fifteen times higher than in blank fields. These results strongly support the
idea that high redshift radio galaxies are the progenitors of central brightest
cluster galaxies located in the progenitors of clusters of galaxies.


title: Observational Aspects of Wave Acceleration in Open Magnetic Regions

abstract:
  This paper reviews the latest observational evidence for the existence of
propagating waves in the open magnetic flux tubes of the solar corona. SOHO
measurements have put tentative limits on the fluxes of various types of
magnetohydrodynamic (MHD) waves in the acceleration region of the solar wind.
Also, continually improving measurements of fluctuations at larger distances
(i.e., in situ detection and radio scintillation) continue to provide
significant constraints on the dominant types of plasma oscillation throughout
the corona and wind. The dissipation of MHD fluctuations of some kind, probably
involving anisotropic turbulent cascade, is believed to dominate the heating of
the extended corona. Spectroscopic observations from the UVCS instrument on
SOHO have helped to narrow the field of possibilities for the precise modes,
generation mechanisms, and damping channels. This presentation will also review
some of the collisionless, kinetic aspects of wave heating and acceleration
that are tied closely to the observational constraints.


title: The Egg Nebula (AFGL 2688): Deepening Enigma

abstract:
  Recent observations of the Egg Nebula (AFGL 2688), obtained at
ever-increasing spatial and spectral resolution, have revealed a perplexing
array of phenomena. Many of these phenomena present challenges to our
understanding of this object as an emerging, bipolar planetary nebula. Here, we
consider two particularly intriguing aspects of the Egg: the peculiar structure
and kinematics of its equatorial regions, and the nature of an apparent widely
separated companion to the central star. In the first case, we use recently
acquired Hubble Space Telescope images to demonstrate that the H2 emission
distributed east and west of the central star is spatially coincident with a
dusty, equatorial disk or torus. The H2 is thus constrained to lie near the
equatorial plane, casting doubt on pure radial outflow models for the
equatorial kinematics. In the second case, we show that the apparent companion
(``Peak A'') may be an accreting white dwarf that has undergone one or more
thermonuclear bursts.


title: Probing the Low Mass Stellar End of the eta Chamaeleontis Cluster

abstract:
  We have identified three faint new members of the eta Chamaeleontis cluster.
Spectral types of the new members are estimated to be ~M5 based on their TiO
band strengths and broadband colors. With an age of 5-8 Myr for the cluster,
masses of these new members are estimated to be ~0.08 Msun. All three display
strong Li 6708A absorption and Halpha emission features including one with
Halpha emission equivalent width ~60A along with HeI 6678 & 7605 A emission
features that are characteristics of classical T Tauri stars.


title: Mechanism for Vanishing Zero-Point Energy

abstract:
  In addition to the two standard solutions of the quantum field equations
having the form e^{+/-(iwt-ikx)}, there exist two additional solutions of the
form e^{+/-(iwt+ikx). By incorporating these latter solutions, deemed
"supplemental solutions", into the development of quantum field theory, one
finds a simple and natural cancellation of terms that results in an energy VEV,
and a cosmological constant, of zero. This fundamental, and previously
unrecognized, inherent symmetry in quantum field theory shows promise for
providing a resolution of the large vacuum energy problem, simply and directly,
with little modification or extension to the extant mathematics of the theory.
In certain scenarios, slight asymmetries could give rise to dark energy.


title:
Distance to the Centaurus cluster and its subcomponents from surface
  brightness fluctuations

abstract:
  We present I-band Surface Brightness Fluctuations (SBF) measurements for 15
early type galaxies (3 giants, 12 dwarfs) in the central region of the
Centaurus cluster, based on VLT FORS1 imaging data. From the SBF-distances to
our sample galaxies we determine the distance of the Centaurus cluster to be
41.3 +/- 2.1 Mpc (33.08 +/- 0.11 mag), about the same distance as of the
``Great Attractor''. We find a distance difference of 0.27 +/- 0.34 mag between
the two subcomponents Cen30 and Cen45, ruling out that both components are
separated by their Hubble flow distance. A distance difference of 0.48 +/- 0.21
mag is found between the central galaxies NGC 4696 (Cen30) and NGC 4709 (Cen45)
of both components, supported by the different turn-over magnitudes of their
respective globular cluster systems. This suggests that Cen45 is falling into
but has not yet reached Cen30, supporting the idea of a large scale filament
along the line of sight towards Centaurus (Churazov et al. 1999). H_0=83.0 +/-
8.3 km/s/Mpc is obtained for our Cen30 sample. This value corresponds to a much
smaller Hubble flow distortion in the direction of Centaurus than determined by
Tonry et al. (2000), implying that the GA mass estimate by Tonry et al. may be
too high and/or that the Centaurus cluster falls into the GA almost
perpendicularly to the line of sight. As our mean single measurement error is
very close to the measured distance scatter of the investigated galaxies, we
can only derive an upper limit of +/- 10 Mpc radial extension for the Centaurus
cluster. No evidence for an infall pattern into the Great Attractor is found
within the uncertainties for the 11 galaxies with measured redshift.


title: New limits on Planck scale Lorentz violation in QED

abstract:
  Constraints on possible Lorentz symmetry violation (LV) of order E/M_Planck
for electrons and photons in the framework of effective field theory (EFT) are
discussed. Using (i) the report of polarized MeV emission from GRB021206 and
(ii) the absence of vacuum \v{C}erenkov radiation from synchrotron electrons in
the Crab nebula, we improve previous bounds by 10^-10 and 10^-2 respectively.
We also show that the LV parameters for positrons and electrons are different,
discuss electron helicity decay, and investigate investigate how prior
constraints are modified by the relations between LV parameters implied by EFT.


title: A birth and growth of a collimated molecular jet from an AGB star

abstract:
  With the VLBA, we have observed water masers associated with the OH/IR star,
W43A, which trace a birth and growth of a molecular jet. The water masers
exhibit the collimated distribution (1700 AU: 20 AU) and fast motions (+/-150
km/s). The maser distribution was well fit by a precessing jet model. The jet
length has extended by 800 AU within 8 years, indicating that the extension
rate is roughly equivalent to the jet speed (150 km/s). Very likely the jet was
born around the year 1960. An elongated planetary nebula will be formed by such
a jet during an extremely short period (<<1000 yrs) of the transition to form a
ptoto-planetary nebula. Then fading of the water maser jet will be observed
during our human life.


title: Electromagnetic Mechanism for the Origin of Knots in Parsec Scale Jets

abstract:
  We consider the propagation and stability of the helical electromagnetic
perturbations in a relativistic force-free Pointing flux dominated jet
(magnetic helix). Perturbations are found to dissipate energy in the vicinity
of the resonant surfaces inside the jet, where the resonance of the
perturbation with the Alfven waves occurs. The energy of the perturbations is
converted into the energy of accelerated particles, which emit synchrotron
radiation. The intensity and polarization of this radiation is modulated with
the perturbation. Perturbations with vanishing group velocity are the most
important and could be associated with the bright knots in parsec scale jets.


title: Topics in Core-Collapse Supernova Theory

abstract:
  There are many interesting topics at the intersection of physics and
astrophysics we call Supernova Theory. A small subset of them include the
origin of pulsar kicks, gravitational radiation signatures of core bounce, and
the possible roles of neutrinos and rotation in the mechanism of explosion. In
this brief communication we summarize various recent ideas and calculations
that bear on these themes.


title:
Mass motions and chromospheres of RGB stars in the globular cluster NGC
  2808

abstract:
  We present the results of the first observations, taken with FLAMES during
Science Verification, of red giant branch (RGB) stars in the globular cluster
NGC 2808. A total of 137 stars was observed, of which 20 at high resolution
(R=47,000) with UVES and the others at lower resolution (R=19,000-29,000) with
GIRAFFE in MEDUSA mode, monitoring ~ 3 mag down from the RGB tip. Spectra were
taken of the Halpha, Na I D and Ca II H and K lines. This is by far the largest
and most complete collection of such data in globular cluster giants, both for
the number of stars observed within one cluster, and for monitoring all the
most important optical diagnostics of chromospheric activity/mass
motions.Evidence of mass motions in the atmospheres was searched from asymmetry
in the profiles and coreshifts of the Halpha, Na I D and Ca II K lines, as well
as from Halpha emission wings. We have set the detection thresholds for the
onset of Halpha emission, negative Na D_2 coreshifts and negative K_3
coreshifts at log L/Lsun ~ 2.5, 2.9 and 2.8, respectively. These limits are
significantly fainter than the results found by nearly all previous studies.
Also the fraction of stars where these features have been detected has been
increased significantly with respect to the previous studies. Our observations
confirm the widespread presence of chromospheres among globular cluster giants,
as it was found among Population I red giants. Some of the above diagnostics
suggest clearly the presence of outward mass motions in the atmosphere of
several stars.


title: MeV Dark Matter: Has It Been Detected?

abstract:
  We discuss the possibility that the recent detection of 511 keV gamma-rays
from the galactic bulge, as observed by INTEGRAL, is a consequence of low mass
(~MeV) particle dark matter annihilations. We discuss the type of halo profile
favored by the observations as well as the size of the annihilation cross
section needed to account for the signal. We find that such a scenario is
consistent with the observed dark matter relic density and other constraints
from astrophysics and particle physics.


title: Optical Counterpart of The Ultraluminous X-ray Source NGC 1313 X-2

abstract:
  We present new optical and {\it Chandra} observations of the field containing
the ultraluminous X-ray source NGC1313 X-2. On an ESO 3.6 m image, the {\it
Chandra} error box embraces a $R=21.6$ mag stellar-like object and excludes a
previously proposed optical counterpart. The resulting X-ray/optical flux ratio
of NGC 1313 X-2 is $\sim 500$. The value of $f_X/f_{opt}$, the X-ray
variability history and spectral distribution indicate a luminous X-ray binary
in NGC 1313 as a likely explanation for NGC 1313 X-2. The inferred optical
luminosity ($L\approx 10^5 L_\odot$) is consistent with that of a $\approx 10
M_\odot$ companion.


title:
Chemically consistent evolution of galaxies: II. Spectrophotometric
  evolution from zero to high redshift

abstract:
  We present a new generation of chemically consistent evolutionary synthesis
models for galaxies of various spectral types from E through Sd. The models
follow the chemical enrichment of the ISM and take into account the increasing
initial metallicity of successive stellar generations using recently published
metallicity dependent stellar evolutionary isochrones, spectra and yields. Our
first set of closed-box 1-zone models does not include any spatial resolution
or dynamics. For a Salpeter initial mass function (IMF) the star formation
rate(SFR) and its time evolution are shown to successfully parameterise
spectral galaxy types E, ..., Sd. We show how the stellar metallicity
distribution in various galaxy types build up with time to yield after $\sim
12$ Gyr agreement with stellar metallicity distributions observed in our and
other local galaxies. The models give integrated galaxy spectra over a wide
wavelength range (90.9\AA - 160$\mu$m), which for ages of $\sim 12$ Gyr are in
good agreement not only with observed broad band colours but also with template
spectra for the respective galaxy types. Using filter functions for
Johnson-Cousins, as well as for HST broad band filters in the optical and
Bessel & Brett's NIR filter system, we calculate the luminosity and colour
evolution of model galaxies over a Hubble time. Including a standard
cosmological model and the attenuation by intergalactic hydrogen we present
evolutionary and cosmological corrections as well as apparent luminosities in
various filters over the redshift range from z $\sim 5$ to the present for our
galaxy types and compare to earlier models using single (=solar) metallicity
input physics only. We also present a first comparison of our cc models to HDF
data.(Abridged abstract)


title:
Optical and Near-IR Spectra of O-rich Mira Variables : a Comparison
  between Models and Observations

abstract:
  Pulsation models are crucial for the interpretation of spectrophotometric and
interferometric observations of Mira variables. Comparing predicted and
observed spectra is one way of establishing the validity of such models. In
this paper, we focus on the models published between 1996 and 1998 by Bessell,
Hofmann, Scholz and Wood. A few new model spectra are added, to improve
available phase coverage. We compare the synthetic spectra with observed low
resolution spectra of optically selected oxygen-rich Miras, over a range of
optical and near-IR wavelengths that encompasses most of the stellar energy
output. We investigate the overall energy distributions, and specific spectral
features in the near-IR wavelength range. The agreement between the observed
and the model-predicted properties is found to be reasonably good. However,
there are discrepancies seen especially in various molecular bands. We find
that different combinations of stellar parameters and pulsation phases often
result in very similar model spectra. Therefore the problem of deriving
parameters of a Mira variable from its spectrum has no unique solution. More
advanced models than presently available, providing even better fits to the
data and covering a wider range of parameters, would be needed to achieve
better discrimination.


title:
A search for extragalactic H2O maser emission towards IRAS galaxies II -
  Discovery of an H2O maser in the Seyfert 1 galaxy NGC 4051

abstract:
  Water vapor maser emission in the 6_{16}-5_{23} transition towards the
narrow-line Seyfert 1 (NLS1) galaxy NGC 4051 has been discovered during an
ongoing single-dish extragalactic water maser survey. The Doppler-shifted maser
components appear to bracket maser components lying near the systemic velocity
of the galaxy symmetrically. The tentative result of a Very Large Array (VLA)
snapshot observation is that the masers are confined within 0.1 arcsec (5 pc at
a distance D = 9.7 Mpc) of the radio continuum peak seen at 8.4 GHz. The low
luminosity of the maser (~2 Lsun) is not typical for masers that coincide with
the radio continuum nucleus and appear associated with Active Galactic Nucleus
(AGN) activity.
  A low-luminosity maser in a Type 1 Seyfert nucleus could be explained by a
low maser gain resulting from the lower inclination of an obscuring disk around
an active nucleus.


title: Asiago eclipsing binaries program. I. V432 Aur

abstract:
  The orbit and physical parameters of the previously unsolved eclipsing binary
V432 Aur, discovered by Hipparcos, have been derived with errors better than 1%
from extensive Echelle spectroscopy and B, V photometry. Synthetic spectral
analysis of both components has been performed, yielding T_eff and log g in
close agreement with the orbital solution, a metallicity [Z/Z_sun]=-0.60 and
rotational synchronization for both components. Direct comparison on the
theoretical L, T_eff plane with the Padova evolutionary tracks and isochrones
for the masses of the two components (1.22 and 1.08 M_sun) provides a perfect
match and a 3.75 Gyr age. The more massive and cooler component is approaching
the base of the giant branch and displays a probable pulsation activity with an
amplitude of Delta V = 0.075 mag and Delta rad.vel. = 1.5 km/sec. With a T_eff
= 6080 K it falls to the red of the nearby instability strip populated by delta
Sct and gamma Dor types of pulsating variables. Orbital modeling reveals a
large and bright surface spot on it. The pulsations activity and the large
spot(s) suggest the presence of macro-turbulent motions in its atmosphere. They
reflect in a line broadening that at cursory inspection could be taken as
indication of a rotation faster than synchronization, something obviously odd
for an old, expanding star.


title: Evolution of Second-Order Cosmological Perturbations and Non-Gaussianity

abstract:
  We present a second-order gauge-invariant formalism to study the evolution of
curvature perturbations in a Friedmann-Robertson-Walker universe filled by
multiple interacting fluids. We apply such a general formalism to describe the
evolution of the second-order curvature perturbations in the standard
one-single field inflation, in the curvaton and in the inhomogeneous reheating
scenarios for the generation of the cosmological perturbations. Moreover, we
provide the exact expression for the second-order temperature anisotropies on
large scales, including second-order gravitational effects and extend the
well-known formula for the Sachs-Wolfe effect at linear order. Our findings
clarify what is the exact non-linearity parameter f_NL entering in the
determination of higher-order statistics such as the bispectrum of Cosmic
Microwave Background temperature anisotropies. Finally, we compute the level of
non-Gaussianity in each scenario for the creation of cosmological
perturbations.


title: Absorption Line Studies in the Halo

abstract:
  Significant progress has been made over the last few years to explore the
gaseous halo of the Milky Way by way of absorption spectroscopy. I review
recent results on absorption line studies in the halo using various
instruments, such as the Far Ultraviolet Spectroscopic Explorer, the Space
Telescope Imaging Spectrograph, and others. The new studies imply that the
infall of low-metallicity gas, the interaction with the Magellanic Clouds, and
the Galactic Fountain are responsible for the phenomenon of the intermediate-
and high-velocity clouds in the halo. New measurements of highly-ionized gas in
the vicinity of the Milky Way indicate that these clouds are embedded in a
corona of hot gas that extends deep into the intergalactic space.


title: Wave effect in gravitational lensing by a cosmic string

abstract:
  The wave effect in the gravitational lensing phenomenon by a straight cosmic
string is investigated. The interference pattern is expressed in terms of a
simple formula. We demonstrate that modulations of the interfered wave
amplitude can be a unique signature of the wave effect. We briefly mention a
possible chance of detecting the wave effect in future gravitational wave
observatories.


title:
Signatures of Magnetized Large Scale Structure in Ultra-High Energy
  Cosmic Rays

abstract:
  We investigate the impact of a structured universe in the multi-pole moments,
auto-correlation function, and cluster statistics of cosmic rays above 10^19
eV. We compare structured and uniform source distributions with and without
magnetic fields obtained from a cosmological simulation. We find that current
data marginally favor structured source distributions and magnetic fields
reaching a few micro Gauss in galaxy clusters but below 0.1 micro Gauss in our
local extragalactic neighborhood. A pronounced GZK cutoff is also predicted in
this scenario. Future experiments will make the degree scale auto-correlation
function a sensitive probe of micro Gauss fields surrounding the sources.


title: Path Integral Formulation for Wave Effect in Multi-lens System

abstract:
  A formula to investigate wave effect in multi-lens system is presented on the
basis of path integral formalism by generalizing the work by Nakamura and
Deguchi (1999). Wave effect of a system with two lenses is investigated in an
analytic way as a simple application to demonstrate usefulness of the formula
and variety of wave effect in multi-lens system.


title:
Mid-IR spectroscopy of T Tauri stars in Chamealeon I: evidence for
  processed dust at the earliest stages

abstract:
  We present mid-IR spectroscopy of three T Tauri stars in the young Chamealeon
I dark cloud obtained with TIMMI2 on the ESO 3.6m telescope. In these three
stars, the silicate emission band at 9.7 micron is prominent. We model it with
a mixture of amorphous olivine grains of different size, crystalline silicates
and silica. The fractional mass of these various components change widely from
star to star. While the spectrum of CR Cha is dominated by small amorphous
silicates, in VW Cha (and in a lesser degree in Glass I), there is clear
evidence of a large amount of processed dust in the form of crystalline
silicates and large amorphous grains. This is the first time that processed
dust has been detetected in very young T Tauri stars (~ 1 Myr).


title: Weak lensing shear and aperture-mass from linear to non-linear scales

abstract:
  In this paper we describe the predictions for the smoothed weak lensing shear
and aperture-mass of two simple analytical models of the density field: the
minimal tree-model and the stellar model. Both models give identical results
for the statistics of the 3-d density contrast smoothed over spherical cells
and only differ by the detailed angular dependence of the many-body density
correlations. We have shown in previous work that they also yield almost
identical results for the pdf of the smoothed convergence, $\kappa_s$. We find
that both models give rather close results for both the shear and the positive
tail of the aperture-mass. However, we note that at small angular scales
($\theta_s \la 2'$) the tail of the pdf $\cP(\Map)$ for negative $\Map$ shows a
strong variation between the two models and the stellar model actually breaks
down for $\theta_s \la 0.4'$ and $\Map<0$. This shows that the statistics of
the aperture-mass provides a very precise probe of the detailed structure of
the density field, as it is sensitive to both the amplitude and the detailed
angular behaviour of the many-body correlations. On the other hand, the minimal
tree-model shows good agreement with numerical simulations over all scales and
redshifts of interest, while both models provide a good description of the pdf
$\cP(\gamma_{is})$ of the smoothed shear components. Therefore, the shear and
the aperture-mass provide robust and complimentary tools to measure the
cosmological parameters as well as the detailed statistical properties of the
density field.


title: Close and distant reprocessing media in Mkn509 studied with BeppoSAX

abstract:
  We present the broad band analysis of two BeppoSAX observations of the Sy 1
Mkn509. In 2000 the source was in a typical flux state,
F{2-10keV}=2.7x10^{-11}erg cm^{-2} s^{-1}, while in 1998 it was found in a high
flux state, F{2-10keV}=5.7x10^{-11} erg cm^{-2} s^{-1}. A comparison between
the two states shows a energy-dependent flux variation. A soft excess, a narrow
iron line and a Compton reflection hump above 10 keV, are clearly apparent in
the residuals after fitting the spectra with a simple power law. We tested two
alternative models. In the first the iron line and the high energy bump are
well reproduced by reprocessing in a cold and Compton thick material. The
intensity of the iron line (also consistent with a Chandra measurement) as well
as the normalization of the reflection hump are consistent with a constant in
the two epochs: this, combined with the fact that the line is narrow as
observed by Chandra, suggests a common origin from distant and optically thick
matter. This model further requires a component to model the soft excess: the
empirical choice of two black bodies accounts well for the excess in both
observations, their combined strength was a factor about three higher in the
high than in the low flux state defined above. However the relative
contribution of the soft excess is higher in the low flux state. In the second
model we attempted to reproduce all spectral features, except for the narrow
cold line, with reflection from an ionized disc. This model is successful only
in the high flux state,but it fails in the low flux state, when the soft excess
is only partially accounted for. In either models, the slope of the power law
is larger in the high than in the low flux state, in agreement with a behaviour
known to be shared by several objects of the same type.


title: A Survey for EHB Stars in the Galactic Bulge

abstract:
  We present a progress report on an extensive survey to find and characterize
all types of blue horizontal-branch stars in the nuclear bulge of the Galaxy.
We have obtained wide, shallow imaging in UBV of ~12 square degrees in the
bulge, with follow-up spectroscopy for radial velocities and metal abundance
determinations. We have discovered a number of metal-rich blue HB stars, whose
presence in the bulge is expected by the interpretation of the extragalactic
ultraviolet excess. Very deep images have been obtained in UBV and SDSS u along
the bulge minor axis, which reveal a significant number of EHB candidates
fainter than B = 19, i.e., with the same absolute magnitudes as EHB stars in
several globular clusters.


title: The black hole--bulge relation in AGNs

abstract:
  We used the widths of H$\beta$ and [OIII] emission lines to investigate the
black hole--bulge relation in radio-loud AGNs, radio-quiet AGNs and NLS1s. The
central black hole mass, $M_{bh}$, is estimated from the H$\beta$ line width
and the optical luminosity, and the bulge velocity dispersion, $\sigma$, is
directly from the width of [OIII] line. We found that the radio-quiet AGNs
follow the established $M_{bh}-\sigma$ relationship in nearby inactive
galaxies, while the radio-loud AGNs and NLS1s deviate from this relationship.
There are two plausible interpretations for the deviation of radio-loud AGNs.
One is that the size of broad line regions (BLRs) emitting H$\beta$ line is
overestimated because of the overestimation of optical luminosity, the other is
that the dynamics of BLRs and/or narrow line regions (NLRs) in radio-loud AGNs
is different from that in radio-quiet AGNs. The deviation of NLS1s may be due
to the small inclination of BLRs to the line of sight or the reliability of
[OIII] line width as the indicator of stellar velocity dispersion because of
its complex multiple components.


title: Difference of $\alpha$-disks between Seyfert 1 galaxies and Quasars

abstract:
  In a previous paper (Bian & Zhao 2002), it was suggested that contamination
to the luminosity of galactic nucleus from the host galaxies play an important
role in determining parameters of the standard $\alpha$ disk for AGNs. Using
the nuclear absolute B band magnitude instead of the total absolute B band
magnitude, the central black hole masses, the accretion rates and the disk
inclinations to the line of sight for 20 Seyfert 1 galaxies and 17
Palomar-Green (PG) quasars were recalculated. It was found that small value of
$\alpha$ is needed in the accretion disk for Seyfert 1 galaxies compared with
PG quasars. The difference of $\alpha$ maybe lead to the different properties
between Seyfert 1 galaxies and Quasars. Furthermore, we found most of the
objects in this sample are not accreting at super-Eddington rates when we
adopted the nuclear optical luminosity in our calculation.


title: Physics of Primordial Universe

abstract:
  The physical basis of the modern cosmological inflationary models with
baryosynthesis and nonbaryonic dark matter and energy implies such predictions
of particle theory, that, in turn, apply to cosmology for their test. It makes
physics of early Universe ambiguous and particle model dependent. The study of
modern cosmology is inevitably linked with the probe for the new physics,
underlying it. The particle model dependent phenomena, such as unstable dark
matter, primordial black holes, strong primordial inhomogeneities, can play
important role in revealing the true physical cosmology. Such phenomena, having
serious physical grounds and leading to new nontrivial cosmological scenarious,
should be taken into account in the data analysis of observational cosmology.


title: Cosmoparticle Physics -the Challenge for the Millenium

abstract:
  Cosmoparticle physics is the natural result of development of mutual
relationship between cosmology and particle physics. Its prospects offer the
way to study the theory of everything and the true history of the Universe,
based on it, in the proper combination of their indirect physical,
astrophysical and cosmological signatures. We may be near the first positive
results in this direction. The basic ideas of cosmoparticle physics are briefly
reviewed.


title:
172 ks Chandra Exposure of the LALA Bo\"{o}tes Field: X-ray Source
  Catalog

abstract:
  We present an analysis of a deep, 172 ks Chandra observation of the Large
Area Lyman Alpha Survey (LALA) Bo\"{o}tes field, obtained with the Advanced CCD
Imaging Spectrometer (ACIS-I) on the Chandra X-ray Observatory. This is one of
the deepest Chandra images of the extragalactic sky; only the 2 Ms CDF-N and 1
Ms CDF-S are substantially deeper. A total of 168 X-ray sources were detected.
The X-ray source counts were derived and compared with those from other Chandra
deep surveys; the hard X-ray source density of the LALA Bo\"{o}tes field is 33%
higher than that of CDF-S at the flux level of 2.0E-15 ergs/cm^2/s, confirming
the field-to-field variances of the hard band source counts reported by
previous studies. The deep exposure resolves > 72% of the 2-10 keV X-ray
background.
  Our primary optical data are R-band imaging from NOAO Deep Wide-Field Survey
(NDWFS), with limiting magnitude of R = 25.7 (Vega, 3sigma, 4" diameter
aperture). We have found optical counterparts for 152 of the 168 Chandra
sources (90%). Among the R-band non-detected sources, not more than 11 of them
can possibly be at z > 5, based on the hardness ratios of their X-ray emission
and nondetections in bluer bands. The majority (~76%) of the X-ray sources are
found to have log(f_X/f_R) within 0.0+-1, which are believed to be AGNs.Most of
the X-ray faint/optically bright sources (log(f_X/f_R) < -1.0) are optically
extended, which are low-z normal galaxies or low luminosity AGNs. There is also
a population of sources which are X-ray overluminous for their optical
magnitudes (log(f_X/f_R) > 1.0), which are harder in X-ray and are probably
obscured AGNs. (abridged)


title:
Simulation of stellar instabilities with vastly different timescales
  using domain decomposition

abstract:
  Strange mode instabilities in the envelopes of massive stars lead to shock
waves, which can oscillate on a much shorter timescale than that associated
with the primary instability. The phenomenon is studied by direct numerical
simulation using a, with respect to time, implicit Lagrangian scheme, which
allows for the variation by several orders of magnitude of the dependent
variables. The timestep for the simulation of the system is reduced appreciably
by the shock oscillations and prevents its long term study. A procedure based
on domain decomposition is proposed to surmount the difficulty of vastly
different timescales in various regions of the stellar envelope and thus to
enable the desired long term simulations. Criteria for domain decomposition are
derived and the proper treatment of the resulting inner boundaries is
discussed. Tests of the approach are presented and its viability is
demonstrated by application to a model for the star P Cygni. In this
investigation primarily the feasibility of domain decomposition for the problem
considered is studied. We intend to use the results as the basis of an
extension to two dimensional simulations.


title: Ambipolar Diffusion in the Magnetorotational Instability

abstract:
  The effects of ambipolar diffusion on the linear stability of weakly ionised
accretion discs are examined. Earlier work on this topic has focused on axial
magnetic fields and perturbation wavenumbers. We consider here more general
field and wavenumber geometries, and find that qualitatively new results are
obtained. Provided a radial wavenumber and azimuthal field are present along
with their axial counterparts, ambipolar diffusion will always be
destabilising, with unstable local modes appearing at well-defined wavenumber
bands. The wavenumber corresponding to the maximum growth rate need not, in
general, lie along the vertical axis. Growth rates become small relative to the
local angular velocity when the ion-neutral collision time exceeds the orbital
time. In common with Hall electromotive forces, ambipolar diffusion
destabilises both positive and negative angular velocity gradients. In at least
some cases, therefore, uniformly rotating molecular cloud cores may reflect the
marginally stable state of the ambipolar magnetorotational instability.


title: Instabilities of captured shocks in the envelopes of massive stars

abstract:
  The evolution of strange mode instabilities into the non linear regime has
been followed by numerical simulation for an envelope model of a massive star
having solar chemical composition, M=50M_sun, T_eff=10^4K and L=1.17*10^6
L_sun. Contrary to previously studied models, for these parameters shocks are
captured in the H-ionisation zone and perform rapid oscillations within the
latter. A linear stability analysis is performed to verify that this behaviour
is physical. The origin of an instability discovered in this way is identified
by construction of an analytical model. As a result, the stratification turns
out to be essential for instability. The difference to common stratification
instabilities, e.g., convective instabilities, is discussed.


title: Interstellar Dust Scattering Properties

abstract:
  Studies of dust scattering properties in astrophysical objects with Milky Way
interstellar dust are reviewed. Such objects are reflection nebulae, dark
clouds, and the Diffuse Galactic Light (DGL). To ensure their basic quality,
studies had to satisfy four basic criteria to be included in this review. These
four criteria significantly reduced the scatter in dust properties
measurements, especially in the case of the DGL. Determinations of dust
scattering properties were found to be internally consistent for each object
type as well as consistent between object types. The 2175 A bump is seen as an
absorption feature. Comparisons with dust grain models find general agreement
with significant disagreements at particular wavelengths (especially in the
far-ultraviolet). Finally, unanswered questions and future directions are
enumerated.


title: Quantifying the bimodal color-magnitude distribution of galaxies

abstract:
  We analyse the bivariate distribution, in color versus absolute magnitude
(u-r vs. M_r), of a low redshift sample of galaxies from the Sloan Digital Sky
Survey (SDSS; 2400 deg^2, 0.004<z<0.08, -23.5<M_r<-15.5). We trace the
bimodality of the distribution from luminous to faint galaxies by fitting
double-Gaussians to the color functions separated in absolute magnitude bins.
Color-magnitude (CM) relations are obtained for red and blue distributions
(early- and late-type, predominantly field, galaxies) without using any cut in
morphology. Instead, the analysis is based on the assumption of normal Gaussian
distributions in color. We find that the CM relations are well fit by a
straight line plus a tanh function. Both relations can be described by a
shallow CM trend (slopes of about -0.04, -0.05) plus a steeper transition in
the average galaxy properties over about two magnitudes. The midpoints of the
transitions (M_r=-19.8 and -20.8 for the red and blue distributions,
respectively) occur around 2x10^10 M_solar after converting luminosities to
stellar mass. Separate luminosity functions are obtained for the two
distributions. The red distribution has a more luminous characteristic
magnitude and a shallower faint-end slope (M^*=-21.5, alpha=-0.8) compared to
the blue distribution (alpha=-1.3 depending on the parameterization). These are
approximately converted to galaxy stellar mass functions. The red distribution
galaxies have a higher number density per magnitude for masses greater than
about 3x10^10 M_solar. Using a simple merger model, we show that the
differences between the two functions are consistent with the red distribution
being formed from major galaxy mergers.


title: The Formation and Evolution of Star Clusters and Galaxies

abstract:
  This paper addresses the questions of what we have learned about how and when
dense star clusters form, and what studies of star clusters have revealed about
galaxy formation and evolution. One important observation is that globular
clusters are observed to form in galaxy mergers and starbursts in the local
universe, which both provides constraints on models of globular cluster
formation, and suggests that similar physical conditions existed when most
early-type galaxies and their globular clusters formed in the past. A second
important observation is that globular cluster systems typically have bimodal
color distributions. This was predicted by merger models, and indicates an
episodic formation history for elliptical galaxies. A third and very recent
result is the discovery of large populations of intermediate age globular
clusters in several elliptical galaxies through the use of optical to
near-infrared colors. These provide an important link between young cluster
systems observed in starbursts and mergers and old cluster systems. This
continuum of ages of the metal-rich globular cluster systems also indicates
that there is no special age or epoch for the formation of the metal-rich
globular clusters, which comprise about half of the cluster population. The
paper concludes with a brief discussion of recent results on the globular
cluster - low-mass X-ray binary connection.