title: Neutrino Mixing and Nucleosynthesis in Core-Collapse Supernovae

abstract:
  A simple description of core-collapse supernovae is given. Properties of the
neutrino-driven wind, neutrino fluxes and luminosities, reaction rates, and the
equilibrium electron fraction in supernova environments are discussed. Neutrino
mixing and neutrino interactions that are relevant to core-collapse supernovae
are briefly reviewed. The values of electron fraction under several evolution
scenarios that may impact rapid neutron capture process (r-process)
nucleosynthesis are calculated.


title: The Millisecond Pulsars in NGC 6760

abstract:
  We present the results of recent Arecibo and Green Bank observations of the
globular cluster NGC 6760. Using Arecibo, a phase-coherent timing solution has
been obtained for the previously known binary pulsar in this cluster, PSR
J1911+0102A. We have also discovered a new millisecond pulsar in NGC 6760, PSR
J1911+0101B, an isolated object with a rotational period of 5.38 ms and a
dispersion measure DM = 196.7 cm-3 pc. Both pulsars are located within 1.3 core
radii of the cluster center and have negative period derivatives. The resulting
lower limits for the accelerations of the pulsars are within the range expected
given a simple model of the cluster. A search for eclipses in the PSR
J1911+0102A binary system using both telescopes yielded negative results. The
corresponding limits on the extra gas column density at superior conjunction
are consistent with the hypothesis that the observational properties of
ultra-low-mass binary pulsars like PSR J1911+0102A are strongly affected by the
inclination of the orbital plane of the system. Among globular cluster pulsar
populations, that of NGC 6760 exhibits one of the largest known spreads in DM.
This quantity seems to be roughly proportional to a cluster's central DM; this
suggests that the observed spread is caused by a turbulent interstellar medium
at spatial scales of 1 pc.


title:
On the method of estimating emission altitude from relativistic phase
  shift in pulsars

abstract:
  The radiation by relativistic plasma particles is beamed in the direction of
field line tangents in the corotating frame, but in an inertial frame it is
aberrated toward the direction of rotation. We have revised the relation of
aberration phase shift by taking into account of the colatitude of emission
spot and the plasma rotation velocity. In the limit of small angle
approximation, aberration phase shift becomes independent of the inclination
angle alpha and the sight line impact angle beta. However, at larger altitudes
or larger rotation phases, the shift does depend on alpha and beta. We have
given an expression for the phase shift in the intensity profile by taking into
account of aberration, retardation and polar cap currents. We have re-estimated
the emission heights of the six classical pulsars, and analyzed the profile of
a millisecond pulsar PSR J0437-4715 at 1440 MHz by fitting the Gaussians to
pulse components. By this procedure we have been able to identify 11 emission
components of PSR J0437-4715. We propose that they form a emission beam with 5
nested cones centered on the core. Using the phase location of component peaks,
we have estimated the relativistic phase shift and the emission height of conal
components. We find some of the components are emitted from the altitudes as
high as 23 percent of light cylinder radius.


title: Chandra observations of the recurrent nova IM Nor

abstract:
  The recurrent nova IM Nor was observed twice in X-rays with Chandra ACIS-S, 1
and 6 months after the optical outburst. It was not detected in the first
observation, with an upper limit on the X-ray luminosity in the 0.2-10 keV
range L(x) < 4.8 x 10^(30) x (d/1 kpc)^2 erg s^(-1) (where d is the distance to
the nova). Five months later, a hard X-ray source with L(x) = (1.4-2.5) x
10^(32) x (d/1 kpc)^2 erg s^(-1) was detected. The X-ray spectrum appears to be
thermal, but we cannot rule out additional components due to unresolved
emission lines. A blackbody component is likely to contribute to the observed
spectrum, but it has bolometric luminosity L$_{\rm bol} = 2.5 x 10^(33) x (d/1
kpc)^2 erg s^(-1), therefore it is not sufficiently luminous to be due to a
central white dwarf which is still burning hydrogen on the surface. An optical
spectrum, taken 5 months post-outburst, indicates no intrinsic reddening of the
ejecta. Therefore, we conclude that the shell had already become optically thin
to supersoft X-rays, but nuclear burning had already turned off, or was in the
process of turning off at this time. We discuss why this implies that recurrent
novae, even the rare ones with long optical decays like IM Nor, indicating a
large envelope mass, are not statistically significant as type Ia SN
candidates.


title:
Surface Evidence of an Iron-Rich Solar Interior and a Neutron-Rich Solar
  Core

abstract:
  Quantitative data on the solar wind, solar magnetic fields, solar eruptions,
solar neutrinos, and on the planetary material orbiting the Sun all indicate
the presence of an iron-rich solar interior and a neutron star at the core of
the Sun. Solar magnetic fields are deep-seated remnants from the core and/or
Bose-Einstein condensation of Fe-rich material into a rotating superconductor.
Neutron emission from the core triggers a series of reactions that produce
solar luminosity, the H carrier gas that maintains mass separation in the Sun,
and an outpouring of 3 E43 H+ ions per year in the solar wind.


title: Kinematics of water masers in high-mass star forming regions

abstract:
  We have conducted multi-epoch EVN observations of the 22.2 GHz water masers
towards four high-mass star forming regions (Sh 2-255 IR, IRAS 23139+5939,
WB89-234, and OMC2). The (three) observing epochs span a time range of 6
months. In each region, the water maser emission likely originates close
(within a few hundreds of AU) to a forming high-mass YSO. Several maser
features (~10) have been detected for each source and, for those features
persistent over the three epochs, proper motions have been derived. The
amplitudes of the proper motions are found to be larger than the range of
variation of the line-of-sight velocities and in each of the observed sources
the proper motion orientation seems to indicate an expansion motion.
  The gas kinematics traced by the 22.2 GHz water masers is compatible with the
shock-excited nature of water maser emission.
  Three different kinematic models (a spherical expanding shell, a Keplerian
rotating disk, and a conical outflow) were fitted to the 3-dimensional velocity
field of the detected maser features. The results of these fits, together with
the comparison of the VLBI maps with the highest-resolution images of the
sources in several thermal tracers, suggest that the water maser features are
most likely tracing the inner portion of the molecular outflows detected at
much larger-scales.


title:
Space Climate Manifestation in Earth Prices - from Medieval England Up
  to Modern Usa

abstract:
  In this study we continue to search for possible manifestations of space
weather influence on prices of agricultural products and consumables. We note
that the connection between solar activity and prices is based on the causal
chain that includes several nonlinear transition elements. These non-linear
elements are characterized by threshold sensitivity to external parameters and
lead to very inhomogeneous local sensitivity of the price to space weather
conditions. It is noted that "soft type" models are the most adequate for
description of this class of connections. Two main observational effects
suitable for testing causal connections of this type of sensitivity are
considered: burst-like price reactions on changes in solar activity and price
asymmetry for selected phases of the sunspot cycle. The connection, discovered
earlier for wheat prices of Medieval England, is examined in this work on the
basis of another 700-year data set of consumable prices in England. Using the
same technique as in the previous part of our work (Pistilnik and Yom Din 2004)
we show that statistical parameters of the interval distributions for price
bursts of consumables basket and for sunspot minimum states are similar one to
another, like it was reported earlier for wheat price bursts. Possible sources
of these consistencies between three different multiyear samples are discussed.
For search of possible manifestations of the "space weather - wheat market"
connection in modern time, we analyze dynamics of wheat prices in the USA in
the twentieth century. We show that the wheat prices revealed a maximum/minimum
price asymmetry consistent with the phases of the sunspot cycle. We discuss
possible explanations of this observed asymmetry, unexpected under conditions
of globalization of the modern wheat market.


title: Black Holes in Massive Star Clusters

abstract:
  Close encounters and physical collisions between stars in young dense
clusters can result in new channels for stellar evolution, and may lead to the
formation of very massive stars and black holes via runaway merging. We present
some details of this process, using the results of N-body simulations and
simple analytical estimates to place limits on the cluster parameters for which
it expected to occur. For small clusters, the mass of the runaway is
effectively limited by the total number of high-mass stars in the system. For
larger clusters, the runaway mass is determined by the fraction of stars that
can mass-segregate to the cluster core while still on the main sequence. In
typical cases, the result is in the range commonly cited for intermediate-mass
black holes. This mechanism may therefore have important implications for the
formation of massive black holes and black-hole binaries in dense cluster
cores.


title: Obscured Binary Quasar Cores in SDSS J104807.74+005543.5?

abstract:
  We report the discovery of a possible close binary system of quasars in SDSS
J1048+0055. The [OIII]4959,5007 emission lines are clearly double-peaked, and
two discrete radio sources with a projected physical separation of ~20 pc are
found in the VLBA milliarcsec resolution image at 8.4 GHz. Each of the [O
III]4959,5007 doublets and Hbeta can be well modelled by two Gaussians and the
line ratio, [O III]5007/Hbeta ~7, is typical of Seyfert 2 galaxies. No broad
component of Hbeta was detected and its [O III]5007 luminosity, L_[OIII] ~ 9.2
times 10^42 erg s^-1, is comparable to luminous quasars and is a few ten times
more luminous than typical Seyfert galaxies. One natural interpretation is that
SDSS J1048+0055 contains two close quasar-like nuclei and the BLR around them
are obscured. Other possible models are also discussed. We suggest that
double-peaked narrow emission line profile may be an effective way of selecting
candidates of binary black holes with intermediate separation.


title: Extended Source Effects in Substructure Lensing

abstract:
  We investigate the extended source size effects on gravitational lensing in
which a lens consists of a smooth potential and small mass clumps
(``substructure lensing''). We first consider a lens model that consists of a
clump modeled as a singular isothermal sphere (SIS) and a primary lens modeled
as an external background shear and convergence. For this simple model, we
derive analytic formulae for (de)magnification of circularly symmetric top-hat
sources with three types of parity for their lensed images, namely, positive,
negative, and doubly negative parities. Provided that the source size is
sufficiently larger than the Einstein radius of the SIS, we find that in the
positive (doubly negative) parity case, an extended source is always magnified
(demagnified) in comparison with the unperturbed macrolens system, whereas in
the negative parity case, the (de)magnification effect, which depends on the
sign of convergence minus unity is weaker than those in other parities. It is
shown that a measurement of the distortion pattern in a multiply lensed image
enables us to break the degeneracy between the lensing effects of clump mass
and those of clump distance if lensing parameters of the relevant macrolens
model are determined from the position and flux of multiple images. We also
show that an actual density profile of a clump can be directly measured by
analyzing the ``fine structure'' in a multiply lensed image within the Einstein
radius of the clump.


title:
Photometric and spectroscopic study of low mass embedded star clusters
  in reflection nebulae

abstract:
  An analysis of the candidate embedded stellar systems in the reflection
nebulae vdBH-RN26, vdBH-RN38, vdBH-RN53a, GGD20, ESO95-RN18 and NGC6595 is
presented. Optical spectroscopic data from CASLEO (Argentina) in conjunction
with near infrared photometry from the 2MASS Point Source Catalogue were
employed. The analysis is based on source surface density, colour-colour and
colour-magnitude diagrams together with theoretical pre-main sequence
isochrones. We take into account the field population affecting the analysis by
carrying out a statistical subtraction. The fundamental parameters for the
stellar systems were derived. The resulting ages are in the range 1-4 Myr and
the objects are dominated by pre-main sequence stars. The observed masses
locked in the clusters are less than 25 solar masses. The studied systems have
no stars of spectral types earlier than B, indicating that star clusters do not
necessarily evolve through an HII region phase. The relatively small locked
mass combined with the fact that they are not numerous in catalogues suggests
that these low mass clusters are not important donors of stars to the field
populations.


title: Generation of Magnetic Field in the Pre-recombination Era

abstract:
  We study the possibility of generating magnetic fields during the evolution
of electron, proton, and photon plasma in the pre-recombination era. We show
that a small magnetic field can be generated in the second order of
perturbation theory for scalar modes with adiabatic initial conditions. The
amplitude of the field is $\la 10^{-30} \rm G$ at the present epoch for scales
from sub-kpc to $\ga 100 \rm Mpc$.


title:
Partially obscured quasars in the Sloan Digital Sky Survey Early Data
  Release

abstract:
  We have compiled a sample of 21 low redshift (z < 0.3), luminous active
galactic nuclei (AGN) with large Balmer decrements (Halpha/Hbeta > 7) using the
galaxy and QSO catalogs of the Sloan Digital Sky Survey Early Data Release.
Using this sample we attempt to determine the fraction of quasars with large
internal absorption. We find that these AGN have Strong [O III] and broad
Halpha emission, and that starlight dominates the spectra in the blue band,
suggesting that these objects are heavily reddened. Their narrow emission line
ratios are similar to those of Seyfert 2 galaxies, yet the average [O III]5007
emission is ~10 times more luminous. Applying the empirical relation between
the optical continuum and the Balmer line luminosity for blue quasars, we find
that the intrinsic luminosities of these 21 objects are in the range for
quasars. We propose that they are obscured, intermediate type quasars analogous
to type 1.8 and 1.9 Seyfert galaxies. The ratio of these optically selected,
intermediate type quasars to type 1 quasars are found to be around 1, similar
to that for local Seyfert galaxies. Preliminary study indicates that most of
these quasars are hosted in early type galaxies.


title: Abundance trends in the thin and thick disks

abstract:
  The Milky Way harbours two disks that appear distinct concerning
scale-heights, kinematics, and elemental abundance patterns. Recent years have
seen a surge of studies of the elemental abundance trends in the disks using
high resolution spectroscopy. Here I will review and discuss the currently
available data. Special focus will also be put on how we define stars to be
members of either disk, and how current models of galaxy formation favour that
thick disks are formed from several accreted bodies. The ability for the
stellar abundance trends to test such predictions are discussed.


title:
Extra-galactic magnetic fields and the second knee in the cosmic-ray
  spectrum

abstract:
  Recent work suggests that the cosmic ray spectrum may be dominated by
Galactic sources up to ~10^{17.5} eV, and by an extra-Galactic component
beyond, provided this latter cuts off below the transition energy. Here it is
shown that this cut-off could be interpreted in this framework as a signature
of extra-galactic magnetic fields with equivalent average strength B and
coherence length l_c such that B\sqrt{l_c} ~ 2-3.10^{-10} G.Mpc^{1/2}, assuming
l_c < r_L (Larmor radius at 10^{17} eV) and continuously emitting sources with
density 10^{-5}/Mpc^3. The extra-Galactic flux is suppressed below 10^{17} eV
as the diffusive propagation time from the source to the detector becomes
larger than the age of the Universe.


title: X-ray Evidence for Multiple Absorbing Structures in Seyfert Galaxies

abstract:
  We have used X-ray spectra to measure attenuating columns in a large sample
of Seyfert galaxies. Over 30 of these sources have resolved radio jets,
allowing the relative orientation of the nucleus and host galaxy to be
constrained. We have discovered that the distribution of absorbing columns is
strongly correlated with the relative orientation of the Seyfert structures.
This result is inconsistent with unification models including only a torus and
is instead most readily explained if a second absorber is included: in addition
to a Compton-thick, parsec-scale torus there would also be a larger-scale
absorber with N_H < 10^{23} cm^{-2}. The second absorber is aligned with the
host galactic plane while the torus is arbitrarily misaligned.


title:
XMM-Newton and optical follow-up observations of three new polars from
  the Sloan Digital Sky Survey

abstract:
  We report follow-up XMM-Newton and optical observations of three new polars
found in the Sloan Digital Sky Survey. Simple modeling of the X-ray spectra,
and consideration of the details of the X-ray and optical lightcurves
corroborate the polar nature of these three systems and provide further
insights into their accretion characteristics. During the XMM-Newton
observation of SDSS J072910.68+365838.3, X-rays are undetected apart from a
probable flare event, during which we find both the typical hard X-ray
bremsstrahlung component and a very strong line O VII (E=0.57 keV), but no
evidence of a soft blackbody contribution. In SDSS J075240.45+362823.2 we
identify an X-ray eclipse at the beginning of the observation, roughly in phase
with the primary minimum of the optical broad band curve. The X-ray spectra
require the presence of both hard and soft X-ray components, with their
luminosity ratio consistent with that found in other recent XMM-Newton results
on polars. Lastly, SDSS J170053.30+400357.6 appears optically as a very typical
polar, however its large amplitude optical modulation is 180 degrees out of
phase with the variation in our short X-ray lightcurve.


title: The Carnegie Supernova Project

abstract:
  The Carnegie Supernova Project (CSP) is aimed at providing an independent
measure of change in the the Hubble expansion as a function of redshift, and
setting constraints dark energy contribution to the total energy content of the
universe. Using type Ia supernovae (SNIa), the CSP differs from other projects
to date in its goal of providing an I-band restframe Hubble diagram. The CSP is
focused on testing for and reducing systematic uncertainties, obtaining a
sample of multiwavelength observations of approximately 200 supernovae over the
redshift range 0 < z < 0.6. The UBVRIYJHK data for low-redshift supernova are
intended to provide a database for the determination of the Hubble constant,
accurate K- and S-corrections, comparison with theoretical models of
supernovae, and for comparison with the RIYJ data of high-redshift supernovae.
The goal is to measure the evolution of the expansion rate, to characterize the
acceleration of the Universe, and constrain the equation of state, w, to a
precision and accuracy of 10%. We are also exploring the use of Type II SNae as
independent distance indicators. Following an ongoing, initial test period, the
project has begun during the fall of 2004. Here an overview of the project is
given, and some preliminary results from the pilot program are presented.


title: A Young Brown Dwarf Companion to DH Tauri

abstract:
  We present the detection of a young brown dwarf companion DH Tau B associated
with the classical T Tauri star DH Tau. Near-infrared coronagraphic
observations with CIAO on the Subaru Telescope have revealed DH Tau B with H =
\~15 mag located at 2.3" (330 AU) away from the primary DH Tau A. Comparing its
position with a Hubble Space Telescope archive image, we confirmed that DH Tau
A and B share the common proper motion, suggesting that they are physically
associated with each other. The near-infrared color of DH Tau B is consistent
with those of young stellar objects. The near-infrared spectra of DH Tau B show
deep water absorption bands, a strong K I absorption line, and a moderate Na I
absorption line. We derived its effective temperature and surface gravity of
Teff = 2700 -- 2800 K and log g = 4.0--4.5, respectively, by comparing the
observed spectra with synthesized spectra of low-mass objects. The location of
DH Tau B on the HR diagram gives its mass of 30 -- 50 M_Jupiter.


title:
Opening the Treasure Chest: A Newborn Star Cluster Emerges from its Dust
  Pillar in Carina

abstract:
  We present detailed observations of the Treasure Chest, a compact nebula at
the head of a dust pillar in the southern Carina nebula. This object is of
interest because it is an example of a dense young cluster containing at least
one massive star, the formation of which may have been triggered by feedback
from the very massive stars in the Carina nebula, and possibly Eta Car itself.
We investigate both the nebular and stellar content of the object. Near-IR
emission-line images reveal a cavity inside the head of the dust pillar, which
contains a dense cluster of young stars, while the observed spectrum of the
nebula is consistent with an H II region ionized by an O9.5 V star. After
subtracting contamination of field stars within the Carina nebula itself, we
compare the cluster's color magnitude diagram with pre-main-sequence isochrones
to derive a likely cluster age less than about 0.1 Myr. This is in reasonable
agreement with the dynamical age of a few times 10^4 yr for the expanding
nebular cavity, indicating extreme youth. Stars in the Treasure Chest cluster
are highly reddened, with extinction values as large as A_V=50. Two-thirds of
cluster members show strong infrared excess colors indicative of circumstellar
disks, which may prove to be among the highest fraction yet seen for a young
cluster. All evidence suggests that the Treaure Chest is an extremely young
cluster that is just now breaking out of its natal cloud into the surrounding
massive star forming region, and is a good target for more detailed study.


title: SSSPM J1444-2019: an extremely high proper motion, ultracool subdwarf

abstract:
  We present the discovery of a new extreme high proper motion object (3.5
arcsec/year) which we classify as an ultracool subdwarf with [M/H] = -0.5. It
has a formal spectral type of sdM9 but also shows L-type features: while the VO
bands are completely absent, it exhibits extremely strong TiO absorption in its
optical spectrum. With a radial velocity of about -160 km/s and a rough
distance estimate of 16--24 pc, it is likely one of the nearest halo members
crossing the Solar neighbourhood with a heliocentric space velocity of
(U,V,W)=(-244,-256,-100)+/-(32,77,6) km/s.


title: Cosmological Theories of Special and General Relativity - I

abstract:
  In the standard cosmological theory one uses the Einstein concepts of space
and time as were originally introduced for the special theory of relativity and
the general relativity theory. According to this approach all physical
quantities are described in terms of the continuum spatial coordinates and
time. Using general relativity theory a great progress has been made in
understanding the evolution of the Universe. Cosmologists usually measure
spatial distances and redshifts of faraway galaxies as expressed by the Hubble
expansion. In recent years this fact was undertaken to develop new theories in
terms of distances and velocities (redshift). While in Einstein's relativity
the propagation of light plays the major role, in the new theory it is the
expansion of the Universe that takes that role and appears at the outset. The
cosmic time becomes crucial in these recent theories, which in the standard
theory is considered to be absolute but here it is relative. In this lecture
this new approach to cosmology is presented.


title: Cosmological Theories of Special and General Relativity - II

abstract:
  Astronomers measure distances to faraway galaxies and their velocities. They
do that in order to determine the expansion rate of the Universe. In Part I of
these lectures the foundations of the theory of the expansion of the Universe
was given. In this part we present the theory. A formula for the distance of
the galaxy in terms of its velocity is given. It is very simple:
$r(v)=c\tau/\beta\sinh\beta v/c$, where $\tau$ is the Big Bang time, $\beta
=\sqrt{1-\Omega_m}$, and $\Omega_m$ is the mass density of the Universe. For
$\Omega_m<1$ this formula clearly indicates that the Universe is expanding with
acceleration, as experiments clearly show.


title: Surveys of extragalactic sources with Planck

abstract:
  Although the primary goal of ESA's Planck mission is to produce high
resolution maps of the temperature and polarization anisotropies of the Cosmic
Microwave Background (CMB), its high-sensitivity all-sky surveys of
extragalactic sources at 9 frequencies in the range 30--860 GHz will constitute
a major aspect of its science products. In particular, Planck surveys will
provide key information on several highly interesting radio source populations,
such as Flat Spectrum Radio Quasars, BL Lac objects, and, especially, extreme
GHz Peaked Spectrum sources, thought to correspond to the very earliest phases
of the evolution of radio sources. Above 100 GHz, Planck will provide the first
all-sky surveys, that are expected to supply rich samples of highly
gravitationally amplified dusty proto-galaxies and large samples of candidate
proto-clusters at z~2-3, thus shedding light on the evolution of large scale
structure across the cosmic epoch when dark energy should start dominating the
cosmic dynamics.


title: Frequency ratio method for seismic modeling of Gamma Doradus stars

abstract:
  A method for obtaining asteroseismological information of a Gamma Doradus
oscillating star showing at least three pulsation frequencies is presented.
This method is based on a first-order asymptotic g-mode expression, in
agreement with the internal structure of Gamma Doradus stars. The information
obtained is twofold: 1) a possible identification of the radial order n and
degree l of observed frequencies (assuming that these have the same l), and 2)
an estimate of the integral of the buoyancy frequency (Brunt-Vaisala) weighted
over the stellar radius along the radiative zone. The accuracy of the method as
well as its theoretical consistency are also discussed for a typical Gamma
Doradus stellar model. Finally, the frequency ratios method has been tested
with observed frequencies of the Gamma Doradus star HD 12901. The number of
representative models verifying the complete set of constraints (the location
in the HR diagram, the Brunt-Vaisala frequency integral, the observed
metallicity and frequencies and a reliable identification of n and l) is
drastically reduced to six.


title: Stochastic Acceleration in Relativistic Parallel Shocks

abstract:
  (abridged) We present results of test-particle simulations on both the first
and the second order Fermi acceleration at relativistic parallel shock waves.
We consider two scenarios for particle injection: (i) particles injected at the
shock front, then accelerated at the shock by the first order mechanism and
subsequently by the stochastic process in the downstream region; and (ii)
particles injected uniformly throughout the downstream region to the stochastic
process. We show that regardless of the injection scenario, depending on the
magnetic field strength, plasma composition, and the employed turbulence model,
the stochastic mechanism can have considerable effects on the particle spectrum
on temporal and spatial scales too short to be resolved in extragalactic jets.
Stochastic acceleration is shown to be able to produce spectra that are
significantly flatter than the limiting case of particle energy spectral index
-1 of the first order mechanism. Our study also reveals a possibility of
re-acceleration of the stochastically accelerated spectrum at the shock, as
particles at high energies become more and more mobile as their mean free path
increases with energy. Our findings suggest that the role of the second order
mechanism in the turbulent downstream of a relativistic shock with respect to
the first order mechanism at the shock front has been underestimated in the
past, and that the second order mechanism may have significant effects on the
form of the particle spectra and its evolution.


title: Super-Eddington black hole accretion: Polish doughnuts and slim disks

abstract:
  The theory of highly super-Eddington black hole accretion was developed in
the 1980s in Warsaw by Paczynski and his collaborators in terms of "Polish
doughnuts", i.e. low viscosity, rotating accretion flows that are optically
thick, radiation pressure supported, cooled by advection, and radiatively very
inefficient. Polish doughnuts resemble fat tori with two narrow funnels along
rotation axis. The funnels collimate radiation into beams with highly
super-Eddington luminosities. "Slim disks" introduced later by Abramowicz,
Lasota and collaborators, have only moderately super-Eddington accretion rates,
rather disk-like shapes, and almost thermal spectra.


title:
The POINT-AGAPE survey II: An Unrestricted Search for Microlensing
  Events towards M31

abstract:
  An automated search is carried out for microlensing events using a catalogue
of 44554 variable superpixel lightcurves derived from our three-year monitoring
program of M31. Each step of our candidate selection is objective and
reproducible by a computer. Our search is unrestricted, in the sense that it
has no explicit timescale cut. So, it must overcome the awkward problem of
distinguishing long-timescale microlensing events from long-period stellar
variables. The basis of the selection algorithm is the fitting of the
superpixel lightcurves to two different theoretical models, using variable star
and blended microlensing templates. Only if microlensing is preferred is an
event retained as a possible candidate. Further cuts are made with regard to
(i) sampling, (ii) goodness of fit of the peak to a Paczynski curve, (iii)
consistency of the microlensing hypothesis with the absence of a resolved
source, (iv) achromaticity, (v) position in the colour-magnitude diagram and
(vi) signal-to-noise ratio. Our results are reported in terms of first-level
candidates, which are the most trustworthy, and second-level candidates, which
are possible microlensing but have lower signal-to-noise and are more
questionable. The pipeline leaves just 3 first-level candidates, all of which
have very short full-width half-maximum timescale (<5 days) and 3 second-level
candidates, which have timescales of 31, 36 and 51 days respectively. We also
show 16 third-level lightcurves, as an illustration of the events that just
fail the threshold for designation as microlensing candidates. They are almost
certainly mainly variable stars. Two of the 3 first-level candidates correspond
to known events (PA 00-S3 and PA 00-S4) already reported by the POINT-AGAPE
project. The remaining first-level candidate is new.


title: Suppression of Dwarf Galaxy Formation by Cosmic Shocks

abstract:
  We carry out a numerical study of the effects of supernova-driven shocks on
galaxy formation at z=9. These "cosmic explosions" can have a significant
impact on galaxies forming nearby. We study such interactions in two key cases.
In the first case in which the forming galaxy has already virialized, the
impinging shock has only a small effect (< 1% of the gas is removed) and star
formation continues relatively unimpeded. However, in the second case in which
the nearby forming galaxy is at the more diffuse turn-around stage, a large
fraction (~70%) of the gas is stripped away from the host dark-matter halo and
ejected into the intergalactic medium. As the time spent near turn-around is
much longer than the interval from virialization to galaxy formation due to
strong radiative losses, we expect the second case to be more representative of
the majority of outflow-galaxy interactions. Thus SN-driven pregalactic
outflows may be an efficient mechanism for inhibiting the formation of
neighbouring galaxies at high redshift. We briefly outline the possible
cosmological consequences of this effect.


title: Simulating young star clusters with primordial binaries

abstract:
  We simulate a cluster of 144179 stars including 13107 primordial hard
binaries (10% of the total number of single stars and binary centers of mass),
using direct integration of the equations of motion of all stars and binaries
and incorporating the effects of stellar and binary evolution. The initial
conditions are representative of young dense star clusters in the Local Group
and other nearby galaxies like the Antennae and M82.
  We find that the early phase of core collapse, driven by mass segregation, is
not appreciably delayed by the presence of a large number of hard binaries. By
the end of the simulation, at an age of 115Myr, the cluster radius has expanded
by about a factor of two. This may be explained as adiabatic expansion driven
by the loss (via stellar evolution) of about 40% of the initial total mass.
Binary dynamics apparently has little effect on the early cluster expansion.
  During the evolution, the total binary fraction drops at a roughly constant
rate of about 0.01% per Myr. The fraction of very hard binaries, however
increases at about 0.025% per Myr. By the end of the simulation the cluster
contains 37 binaries containing at least one black hole; roughly half (17) of
these contain two black holes.


title:
Creating ultra-compact binaries in globular clusters through stable mass
  transfer

abstract:
  A binary in which a slightly evolved star starts mass transfer to a neutron
star can evolve towards ultra-short orbital periods under the influence of
magnetic braking. This is called magnetic capture. We investigate in detail for
which initial orbital periods and initial donor masses binaries evolve to
periods less than 30-40 minutes within the Hubble time. We show that only small
ranges of initial periods and masses lead to ultra-short periods, and that for
those only a small time interval is spent at ultra-short periods. Consequently,
only a very small fraction of any population of X-ray binaries is expected to
be observed at ultra-short period at any time. If 2 to 6 of the 13 bright X-ray
sources in globular clusters have an ultra-short period, as suggested by recent
observations, their formation cannot be explained by the magnetic capture
model.


title:
The Metallicity dependence of the Cepheid Period-Luminosity relation:
  methodology and results

abstract:
  We present the results of an observational campaign undertaken to assess the
influence of the iron content on the Cepheid Period-Luminosity relation. Our
data indicate that this dependence is not well represented by a simple linear
relation. Rather, the behaviour is markedly non monotonic, with the correction
peaking at about solar metallicity and declining for higher and lower values of
[Fe/H].


title:
Full computation of massive AGB evolution. I. The large impact of
  convection on nucleosynthesis

abstract:
  It is well appreciated that the description of overadiabatic convection
affects the structure of the envelopes of luminous asymptotic giant branch
(AGB) stars in the phase of ``hot bottom burning '' (HBB). We stress that this
important uncertainty in the modeling plays a role which is much more dramatic
than the role which can be ascribed, e.g., to the uncertainty in the nuclear
cross-sections. Due to the role tentatively attributed today to the HBB
nucleosynthesis as the site of self-enrichment of Globular Clusters stars, it
is necessary to explore the difference in nucleosynthesis obtained by different
prescriptions for convection. We present results of detailed evolutionary
calculations of the evolution of stars of intermediate mass during the AGB
phase. We follow carefully the nucleosynthesis at the base of the external
convective region, showing that very different results can be obtained
according to the presciption adopted to find out the temperature gradient
within the instability regions. We discuss the uncertainties in the yields of
the various chemical species and the role which these sources can play as
polluters of the interstellar medium.


title: Cluster Density and the IMF

abstract:
  Observed variations in the IMF are reviewed with an emphasis on environmental
density. The remote field IMF studied in the LMC by several authors is clearly
steeper than most cluster IMFs, which have slopes close to the Salpeter value.
Local field regions of star formation, like Taurus, may have relatively steep
IMFs too. Very dense and massive clusters, like super star clusters, could have
flatter IMFs, or inner-truncated IMFs. We propose that these variations are the
result of three distinct processes during star formation that affect the mass
function in different ways depending on mass range. At solar to intermediate
stellar masses, gas processes involving thermal pressure and supersonic
turbulence determine the basic scale for stellar mass, starting with the
observed pre-stellar condensations, and they define the mass function from
several tenths to several solar masses. Brown dwarfs require extraordinarily
high pressures for fragmentation from the gas, and presumably form inside the
pre-stellar condensations during mutual collisions, secondary fragmentations,
or in disks. High mass stars form in excess of the numbers expected from pure
turbulent fragmentation as pre-stellar condensations coalesce and accrete with
an enhanced gravitational cross section. Variations in the interaction rate,
interaction strength, and accretion rate among the primary fragments formed by
turbulence lead to variations in the relative proportions of brown dwarfs,
solar to intermediate mass stars, and high mass stars.


title: The IMF in Starbursts

abstract:
  The history of the IMF in starburst regions is reviewed. The IMFs are no
longer believed to be top-heavy, although some superstar clusters, whether in
starburst regions or not, could be. General observations of the IMF are
discussed to put the starburst results in perspective. Observed IMF variations
seem to suggest that the IMF varies a little with environment in the sense that
denser and more massive clusters produce more massive stars, and perhaps more
brown dwarfs too, compared to intermediate mass stars.


title:
An infrared study of galactic OH/IR stars. I. An optical/near-IR atlas
  of the Arecibo sample

abstract:
  In this paper we present optical and near-infrared finding charts, accurate
astrometry (~1") and single-epoch near-infrared photometry for 371 IRAS
sources, 96% of those included in the so-called Arecibo sample of OH/IR stars
(Eder et al. 1988; Lewis et al. 1990a; Chengalur et al. 1993). The main
photometric properties of the stars in the sample are presented and discussed
as well as the problems found during the process of identification of the
optical/near-infrared counterparts. In addition, we also identify suitable
reference stars in each field to be used for differential photometry purposes
in the future.
  We find that 39% of the sources (144 in number) have no optical counterpart,
8 of them being invisible even at near infrared wavelengths. The relative
distribution of sources with and without optical counterpart in the IRAS
two-colour diagram and their characteristic near infrared colours are
interpreted as the consequence of the increasing thickness of their
circumstellar shells. Among the objects not detected at near infrared
wavelengths four non-variable sources are proposed to be heavily obscured
post-AGB stars which have just very recently left the AGB. Eight additional
objects with unusually bright and/or blue near-infrared colours are identified
as candidate post-AGB stars and/or proto-planetary nebulae.


title:
Hubble Advanced Camera for Surveys Observations of the z=6.42 Quasar
  SDSS 1148+5251: A Leak in the Gunn-Peterson Trough

abstract:
  The Hubble Advanced Camera for Surveys has been used to obtain a narrow-band
image of the weak emission peak seen at lambda=7205 A in the Gunn-Peterson Ly
beta absorption trough of the highest redshift quasar, SDSS J1148+5251. The
emission looks perfectly point-like; there is no evidence for the intervening
galaxy that we previously suggested might be contaminating the quasar spectrum.
We derive a more accurate astrometric position for the quasar in the two
filters and see no indication of gravitational lensing. We conclude that the
light in the Ly beta trough is leaking through two unusually transparent,
overlapping windows in the IGM absorption, one in the Ly beta forest at z ~ 6
and one in the Ly alpha forest at z ~ 5.
  If there are significant optical depth variations on velocity scales small
compared with our spectral resolution (~150 km/s), the Ly alpha trough becomes
more transparent for a given Ly beta optical depth. Such variations can only
strengthen our conclusion that the fraction of neutral hydrogen in the IGM
increases dramatically at z>6. We argue that the transmission in the Ly beta
trough is not only a more sensitive measure of the neutral fraction than is Ly
alpha, it also provides a less biased estimator of the neutral hydrogen
fraction than does the Ly alpha transmission.


title:
Mid-infrared luminosity as an indicator of the total infrared luminosity
  of galaxies

abstract:
  The infrared (IR) emission plays a crucial role for understanding the star
formation in galaxies hidden by dust. We first examined four estimators of the
IR luminosity of galaxies, L_fir (Helou et al. 1988), L_tir (Dale et al. 2001),
revised version of L_tir (Dale & Helou 2002) (we denote L_tir2), and L_ir
(Sanders & Mirabel 1996) by using the observed SEDs of well-known galaxies. We
found that L_ir provides excellent estimates of the total IR luminosity for a
variety of galaxy SEDs. The performance of L_tir2 was also found to be very
good. Using L_ir, we then statistically analyzed the IRAS PSCz galaxy sample
(Saunders et al. 2000) and found useful formulae relating the MIR monochromatic
luminosities [L(12um) and L(25um)], and L_ir. For this purpose we constructed a
subsample of 1420 galaxies with all IRAS four band (12, 25, 60, and 100um) flux
densities. We found linear relations between L_ir and MIR luminosities, L(12um)
and L(25um). The prediction error with 95-% confidence level is a factor of
4-5. Hence, these formulae are useful for the estimation of the total IR
luminosity only from 12um or 25um observations. We further tried to make an
`interpolation' formula for galaxies at 0<z<1. For this purpose we construct
the formula of the relation between 15-um luminosity and the total IR
luminosity. We conclude that the 15-um formula can be used as an estimator of
the total IR luminosity from 24um observation of galaxies at z \simeq 0.6.


title: Cosmic homogeneity demonstrated with luminous red galaxies

abstract:
  We test the homogeneity of the Universe at $z\sim 0.3$ with the Luminous Red
Galaxy (LRG) spectroscopic sample of the Sloan Digital Sky Survey. First, the
mean number $N(R)$ of LRGs within completely surveyed LRG-centered spheres of
comoving radius $R$ is shown to be proportional to $R^3$ at radii greater than
$R\sim 70 h^{-1} \mathrm{Mpc}$. The test has the virtue that it does not rely
on the assumption that the LRG sample has a finite mean density; its results
show, however, that there \emph{is} such a mean density. Secondly, the survey
sky area is divided into 10 disjoint solid angular regions and the fractional
rms density variations of the LRG sample in the redshift range $0.2<z<0.35$
among these ($\sim 2\times10^7 h^{-3} \mathrm{Mpc^3}$) regions is found to be 7
percent of the mean density. This variance is consistent with typical biased
\lcdm models and puts very strong constraints on the quality of SDSS
photometric calibration.


title: Spectroscopic analysis of tremendous--outburst--nova candidates

abstract:
  In the course of a long-term project investigating classical novae with large
outburst amplitudes, we have performed optical spectroscopy of several old-nova
candidates. We here present the spectra of the candidates V630 Sgr, XX Tau, CQ
Vel, V842 Cen, and V529 Ori, that hitherto lacked such classification. While
the first four show typical spectra for cataclysmic variables, and can thus be
identified as such, V529 Ori is probably misclassified.
  Of special interest are the two systems XX Tau and V842 Cen, which show all
signs for being low mass transfer systems. As such they can be used to judge
the evolution scenarios for novae. In particular, given the rather young age of
their outburst, it appears more likely that these systems are not on their way
into hibernation, (i.e., cutting off mass transfer for a longer period of
time), but are simply settling down towards their original configuration of
comparatively low, but steady, mass transfer, such as for dwarf novae.


title:
Whole Earth Telescope observations of BPM 37093: a seismological test of
  crystallization theory in white dwarfs

abstract:
  BPM 37093 is the only hydrogen-atmosphere white dwarf currently known which
has sufficient mass (~ 1.1 M_sun) to theoretically crystallize while still
inside the ZZ Ceti instability strip (T_eff ~ 12,000 K). As a consequence, this
star represents our first opportunity to test crystallization theory directly.
If the core is substantially crystallized, then the inner boundary for each
pulsation mode will be located at the top of the solid core rather than at the
center of the star, affecting mainly the average period spacing. This is
distinct from the "mode trapping" caused by the stratified surface layers,
which modifies the pulsation periods more selectively. In this paper we report
on Whole Earth Telescope observations of BPM 37093 obtained in 1998 and 1999.
Based on a simple analysis of the average period spacing we conclude that a
large fraction of the total stellar mass is likely to be crystallized.


title: Theory of Outflows in Cataclysmic Variables

abstract:
  We review the main results from line-driven (LD) models of winds from
accretion disks in cataclysmic variables (CVs). We consider LD disk wind models
in the hydrodynamic (HD) and magnetohydrodynamic (MHD limits. We discuss the
basic physical conditions needed for a disk wind to exist and the conditions
for the wind to be steady or unsteady. We also discuss how the line-driven wind
structures revealed in numerical simulations relate to observations. In
particular, we present synthetic line profiles predicted by the LD wind models
and compare them with observations. Our main conclusion is that, despite some
problems, line-driving alone is the most plausible mechanism for driving the CV
winds. This conclusion is related to two facts: 1) LD wind models are likely
the best studied wind models, analytically and numerically, and 2) it is most
likely that the predictive power of the LD wind models is much higher than of
any other wind model so far. Preliminary results from LD-MHD wind models
confirm that magnetic driving is likely an important element of the wind
dynamics. However, magnetic driving does not seem to be necessary to produce a
CV wind. The most important issues which need to be addressed by future
dynamical models, regardless of driving mechanism, are the effects of the
position-dependent photoionization and the dynamical effects in three
dimensions.


title: Discovery of an OH(1720 MHz) Maser in the LMC

abstract:
  We report the first study of OH(1720 MHz) masers in the LMC in order to probe
regions where supernova remnants interact with adjacent molecular clouds. Using
the ATCA, we observed four sources in the LMC and detected a single OH(1720
MHz) maser with a flux density of 377 mJy toward 30 Doradus. No main line
emission at 1665 or 1667 MHz was detected. The observed OH(1720 MHz) maser
emission from 30 Dor shows characteristics similar to the well-known
collisionally-pumped supernova remnant masers found in the Galaxy, though 30
Dor is known as a star forming region. It is possible that shocks driven by a
nearby supernova remnant or by strong stellar winds from young stars are
responsible for production of OH(1720 MHz) maser in 30 Dor. Future studies are
required to distinguish between collisional and radiative pumping mechanisms
for the 30 Dor OH (1720 MHz) maser.


title:
The dynamical structure of isotropic spherical galaxies with a central
  black hole

abstract:
  We discuss the kinematical structure of a two-parameter family of isotropic
models with a central black hole. The family contains the slope of the central
density cusp and the relative black hole mass as parameters. Most of the basic
kinematical quantities of these models can be expressed analytically. This
family contains three distinct models where also the distribution function,
differential energy distribution and spatial LOSVDs can be expressed completely
analytically. Each of these models show a drastically different behaviour of
the distribution function. Although the effect of a black hole on the
distribution function is very strong, in particular for models with a shallow
density cusp, the differential energy distribution is only marginally affected.
We discuss in detail the effects of a central black hole on the LOSVDs. The
projected velocity dispersion increases with black hole mass at small projected
radii, but the effect of a black hole on the shape of the LOSVDs (characterized
by the h4 parameter) is less straightforward to interpret. Too much reliance on
the wings of the LOSVDs and the value of the h4 parameter to determine black
hole masses might hence be dangerous.


title:
Cepheid Period-Luminosity Relations: Galactic vs. LMC and the Results
  from t-Test

abstract:
  The period-luminosity (PL) relation for Galactic Cepheids is derived with
recent independent distance measurements taken from literature. Our PL relation
confirms the work of Tammann et al. (2003), which showed that the Galactic
Cepheids follow a different PL relation to their LMC counterparts. Our results
also show that the slope of the Galactic PL relation is inconsistent with the
LMC slope with more than 95% confidence. The details of this work can be found
in Ngeow & Kanbur (2004).


title:
2MASS Constraints on the Local Large-Scale Structure: A Challenge to
  LCDM?

abstract:
  We investigate the large-scale structure of the local galaxy distribution
using the recently completed 2 Micron All Sky Survey (2MASS). First, we
determine the K-band number counts over the 4000 sq.deg. APM survey area where
evidence for a large-scale `local hole' has previously been detected and
compare them to a homogeneous prediction. Considering a LCDM form for the
2-point angular correlation function, the observed deficiency represents a 5
sigma fluctuation in the galaxy distribution. We check the model normalisation
using faint K-band data compiled from the literature; the normalisation used in
this paper is in excellent agreement, and the observed counts over the APM
survey area would require the model to be lowered by 3.8 sigma. However, the
issue is complicated by the b>20 and b<-20 2MASS counts which lie below the
best-fit model normalisation. Second, since the K-band counts over the APM
survey area continue to suggest the possible presence of excess clustering over
the LCDM prediction, we next probe the power at large scales by comparing the
2MASS and LCDM mock galaxy angular power spectra. We find a 3 sigma excess in
the 2MASS catalogue over the LCDM prediction at large scales (l<30). However,
this excess is not enough to account for the low counts over the APM survey
area. Finally, we apply a counts in cells analysis to the 2MASS data and mock
catalogues; on the assumption that the 2MASS catalogue at |b|>20 is
representative, we find excellent agreement between the biased LCDM mocks and
the 2MASS catalogue to 30 deg. The crux of the interpretation of these results
appears to be whether the 2MASS volume is yet big enough to constitute a fair
sample of the Universe. (abridged)


title: Kinematics of the circumstellar gas around UXOR stars

abstract:
  This thesis presents the results of a high spectral resolution study of the
circumstellar (CS) gas around the intermediate mass, pre-main sequence UXOR
stars BF Ori, SV Cep, UX Ori, WW Vul and XY Per. The results are based on a set
of 38 echelle spectra covering the spectral range 3800-5900 Angstroms,
monitoring the stars on time scales of months, days and hours.
  All spectra show a large number of Balmer and metallic lines with variable
blueshifted and redshifted absorption features superimposed to the photospheric
stellar spectra. Synthetic Kurucz models are used to estimate rotational
velocities, effective temperatures and gravities of the stars. The best
photospheric models are subtracted from each observed spectrum to determine the
variable absorption features due to the circumstellar gas; those features are
characterized, via multigaussian fitting, in terms of their velocity, v,
dispersion velocity, Delta_v, and residual absorption, R_max.
  The absorption components detected in each spectrum can be grouped by their
similar radial velocities and are interpreted as the signature of the dynamical
evolution of gaseous clumps. Most of the events undergo
accelerations/decelerations at a rate of tenths of ms-2. The typical timescale
for the duration of the events is a few days. The dispersion velocity and the
relative absorption strength of the features do not show drastic changes during
the lifetime of the events, which suggests that they are gaseous blobs
preserving their geometrical and physical identity.
  See full abstract in the document


title:
Interpretations of gamma-ray burst spectroscopy. I. Analytical and
  numerical study of spectral lags

abstract:
  We describe the strong spectral evolution that occurs during a gamma-ray
burst pulse and the means by which it can be analyzed. Based on observed
empirical correlations, an analytical model is constructed which is used to
describe the pulse shape and quantize the spectral lags and their dependences
on the spectral evolution parameters. We find that the spectral lag depends
mainly on the pulse-decay time-scale and that hard spectra (with large spectral
power-law indices alpha) give the largest lags. Similarly, large initial
peak-energies, Eo, lead to large lags, except in the case of very soft spectra.
The hardness ratio is found to depend only weakly on alpha and the HIC index,
eta. In particular, for low Eo, it is practically independent, and is
determined mainly by Eo. The relation between the hardness ratio and the lags,
for a certain Eo are described by power-laws, as alpha varies. We also discuss
the expected signatures of a sample of hard spectral pulses (e.g. thermal or
small pitch-angle synchrotron emission) versus soft spectral pulses (e.g.
optically-thin synchrotron emission). Also the expected differences between a
sample of low energetic bursts (such as X-ray flashes) and of high energetic
bursts (classical bursts) are discussed.


title:
Arecibo Measurements of Pulsar--White Dwarf Binaries: Evidence for Heavy
  Neutron Stars

abstract:
  We summarize constraints on neutron star masses from ongoing timing
observations of pulsar-white dwarf binaries at Arecibo. The trend is toward
pulsar masses larger than the canonical value of 1.35 solar masses.


title:
GBT Observations of Very Low Mass Binary Millisecond Pulsars: A Search
  for Eclipses

abstract:
  We searched for eclipses of two millisecond pulsars, PSR J1807-2459 and PSR
B1908+00. These pulsars are in very low mass binary systems with orbital
parameters similar to those of eclipsing binaries. Observations were made with
the GBT at frequencies as low as 575 MHz. No eclipses were detected in either
system. Observations of well-established eclipsing binary J2051-0827 found
eclipses to be substantially weaker than previously seen, with the pulsar
detected throughout the eclipse region at 575 MHz and with an electron column
density an order of magnitude smaller than previously measured.


title: Cosmic Acceleration and Modified Gravitational Models

abstract:
  There is now overwhelming observational evidence that our Universe is
accelerating in its expansion. I discuss how modified gravitational models can
provide an explanation for this observed late-time cosmic acceleration. We
consider specific low-curvature corrections to the Einstein-Hilbert action.
Many of these models generically contain unstable de Sitter solutions and,
depending on the parameters of the theory, late-time accelerating attractor
solutions.


title: Loss Cone Refilling Rates in Galactic Nuclei

abstract:
  A gap in phase space is opened up by a binary supermassive black hole as it
ejects stars in a galactic nucleus. This gap must be refilled before the single
black hole that subsequently forms can disrupt or accrete stars. We compute
loss cone refilling rates for a sample of elliptical galaxies as a function of
the mass ratio of the binary. Refilling times are of order 10 Gyr or longer in
bright elliptical galaxies. Tidal flaring rates in these galaxies might be much
lower than predicted using time-independent models.


title: Exploring Hot Gas in the Galactic Halo and High Velocity Clouds

abstract:
  In the five years since its launch, the Far Ultraviolet Spectroscopic
Explorer has given the astronomical community a marvelous glimpse into the
realm of previously unexplored regions of the Milky Way and its surroundings.
Absorption lines produced by gas along entire paths through the nearby universe
have now been recorded in the spectra of distant QSOs and active galactic
nuclei. Of the lines recorded, the O VI 1031.926, 1037.617 Angstrom doublet is
the best tracer of highly ionized regions. Exciting discoveries include a
definitive confirmation of the hot Galactic halo postulated by Lyman Spitzer
nearly 50 years ago, the discovery of a hot, highly extended Galactic corona
enveloping the Milky Way out to distances of several tens of kiloparsecs, and
the discovery of an extensive network of highly ionized, high velocity clouds
surrounding the Galaxy.


title: Search for Correlated High Energy Cosmic Ray Events with CHICOS

abstract:
  We present the results of a search for time correlations in high energy
cosmic ray data (primary E > 10^{14} eV) collected by the California HIgh
school Cosmic ray ObServatory (CHICOS) array. Data from 60 detector sites
spread over an area of 400 km^2 were studied for evidence of correlated events
separated by more than 1 km with coincidence times ranging from 1 microsec up
to 1 second. All searches were consistent with the absence of excess
coincidences except for a 2.9 sigma excess observed for coincidence times less
than 10 microsec. We report upper limits for the coincidence probability as a
function of coincidence time.


title:
X-ray Gyrations of Eta Carinae, or, Is Presence of Evidence Evidence of
  Presence?

abstract:
  We review the properties of the variable X-ray emission from the extremely
massive star Eta Carinae concentrating on the last X-ray minimum, and briefly
consider the possible role of a binary companion star on the observational
properties of the system.


title: A Second Shell in the Fornax dSph Galaxy

abstract:
  In the search for tidal structure in Galactic satellite systems, we have
conducted a photometric survey over a 10 square degree area centred on the
Fornax dSph galaxy. The survey was made in two colours, and the resulting
colour-magnitude data were used as a mask to select candidate Fornax RGB stars,
thereby increasing the contrast of Fornax stars to background sources in the
outer regions. Previously, we reported the presence of a shell (age 2 Gyr)
located towards the centre of Fornax. In this contribution we reveal a second
shell, significantly larger than the first, located 1.3 degrees NW from the
centre of Fornax, outside the nominal tidal radius. Moreover, the distribution
of Fornax RGB stars reveals two lobes extending to the spatial limit of our
survey, and aligned with the minor axis and with the two shells. These results
support the hypothesis of a merger between Fornax and a gas-rich companion
approximately 2 Gyr ago.


title: Dark Matter Search with Direction Sensitive Scintillators

abstract:
  We have carried out the dark matter search with a 116g direction-sensitive
stilbene crystal in Kamioka Observatory. With the crystal fixed to the earth,
we searched the modulation of thelight output. No modulation signal was found
due to the small size of the detector crystal and the higher background rate
yet to be eliminated. However, it demonstrated the effectiveness of the method
of direction sensitive search for the dark matter with an implementation of the
anisotropic organic scintillation crystal.


title:
Primary Energy Measurement with EAS Cherenkov Light: Experiment QUEST
  and CORSIKA Simulation

abstract:
  A new primary mass independent method of energy measurement has been
developed by exploiting: a) the joint analysis of the shower size, obtained by
EAS-TOP, and of the EAS atmospheric Cherenkov light lateral distribution,
obtained by the QUEST array, and b) simulations based on the CORSIKA/QGSJET
code. The method is based on the correlation between the size/energy ratio and
the steepness of Cherenkov light lateral distribution and has been compared
with a "classical" one based on the Cherenkov light flux at a fixed distance
(175 m) from the EAS core. An absolute energy calibration of the EAS
atmospheric Cherenkov light flux has been obtained.


title: The new infra-red view of evolved stars in IZw18

abstract:
  We report results from near-infrared imaging of IZw18, the most metal-poor
galaxy in the local universe with NICMOS on board the Hubble Space Telescope
(HST). Observations were obtained in the broad F205W filter ($\sim$ K) and in
the medium-wide bands F171M and F180M, the latter which cover strong molecular
absorption features in cool stars. The new data, together with previously
obtained HST/NICMOS images in the F110W ($\sim$ J) and F160W ($\sim$ H)
filters, provide a census of the cool stellar population in this chemically
unevolved galaxy. We find that stars as old as $\sim 1$ Gyr are required to
explain the observed colour-magnitude diagrams. Combining broad and medium-wide
band photometry, we have classified the observed stars. The observed stellar
populations, to the depth of our data, are dominated by luminous red supergiant
stars. However, an intermediate-age component is also present. We have
identified carbon star candidates, and show that they dominate the stellar
content for intermediate mass and age. We show that low metallicity
intermediate-age stars have, for a given colour, a F110W ($\sim$ J-band) excess
compared to local carbon stars. The carbon stars identified in IZw18 are the
most distant (more than 10 Mpc) resolved examples yet discovered.


title:
The Tunka Experiment: Towards a 1-km^2 Cherenkov EAS Array in the Tunka
  Valley

abstract:
  The project of an EAS Cherenkov array in the Tunka valley/Siberia with an
area of about 1 km^2 is presented. The new array will have a ten times bigger
area than the existing Tunka-25 array and will permit a detailed study of the
cosmic ray energy spectrum and the mass composition in the energy range from
10^15 to 10^18 eV.


title: Interpretations of gamma-ray burst spectroscopy. II. Bright BATSE bursts

abstract:
  We analyze the spectral lags of a sample of bright gamma-ray burst pulses
observed by CGRO BATSE and compare these with the results of high-resolution
spectroscopical investigations. We find that pulses with hard spectra have the
largest lags, and that there is a similar, but weaker correlation between
hardness-intensity correlation index, eta, and lag. We also find that the lags
differ considerably between pulses within a burst. Furthermore, the peak energy
mainly decreases with increasing lag. Assuming a lag-luminosity relation as
suggested by Norris et al., there will thus be a positive
luminosity--peak-energy correlation. We also find that the hardness ratio, of
the total flux in two channels, only weakly correlates with the spectral
evolution parameters. These results are consistent with those found in the
analytical and numerical analysis in Paper I. Finally, we find that for these
bursts, dominated by a single pulse, there is a correlation between the
observed energy-flux, F, and the inverse of the lag, t_lag: F propto
t_lag^{-1}. We interpret this flux-lag relation found as a consequence of the
lag-luminosity relation and that these bursts have to be relatively narrowly
distributed in z. However, they still have to, mainly, lie beyond z ~ 0.01,
since they do not coincide with the local super-cluster of galaxies. We discuss
the observed correlations within the collapsar model, in which the collimation
of the outflow varies. Both the thermal photospheric emission as well as
non-thermal, optically-thin synchrotron emission should be important.


title: A general proof of the conservation of the curvature perturbation

abstract:
  Without invoking a perturbative expansion, we define the cosmological
curvature perturbation, and consider its behaviour assuming that the universe
is smooth over a sufficiently large comoving scale. The equations are simple,
resembling closely the first-order equations, and they lead to results which
generalise those already proven in linear perturbation theory and (in part) in
second-order perturbation theory. In particular, the curvature perturbation is
conserved provided that the pressure is a unique function of the energy
density.


title:
New generalized Chaplygin gas as a scheme for unification of dark energy
  and dark matter

abstract:
  We propose in this paper a new model for describing the unification of dark
energy and dark matter. This new model is a further generalization of the
generalized Chaplygin gas (GCG) model, thus dubbed new generalized Chaplygin
gas (NGCG) model. The equation of state of the NGCG is given by $p = -
\tilde{A}(a)/\rho^{\alpha}$, where $a$ is the scale factor and
$\tilde{A}(a)=-w_XAa^{-3(1+w_X)(1+\alpha)}$. We show that the NGCG model is
totally dual to an interacting XCDM parametrization scenario, in which the
interaction between dark energy and dark matter is characterized by the
constant $\alpha$. We discuss the cosmological consequences led by such an
unified dark sectors model. Furthermore, we perform a statefinder analysis on
this scenario and show the discrimination between this scenario and other dark
energy models. Finally, a combined analysis of the data of Type Ia supernovae,
cosmic microwave background, and large scale structure provides a fairly tight
constraint on the parameters of the NGCG model.


title: RIP: The Macho Era (1974-2004)

abstract: This article reviews the life and death of a scientific theory.


title: Models and phenomenology

abstract:
  It is evident that models of the knee should match the observational
phenomenology. In this talk I discuss a few aspects of phenomenology, which are
important not only for the understanding of the knee origin, but also for the
general problem of the origin of cosmic rays. Among them are the shape of the
energy spectrum, its irregularity, the sharpness of the knee and its fine
structure. The classification of models is given and some examples of the most
recent models are discussed. The most probable conclusion deduced from this
examination is that the knee has an astrophysical origin and the so called
'source' models of the knee are most likely among them.


title:
Radiatively driven rotating pair-plasma jets from two component
  accretion flows

abstract:
  Centrifugal pressure of matter spiralling onto black holes, have long been
known to produce standing or oscillating shocks. The post-shock disc puffs up
in the form of a torus, which intercepts soft photons from the outer Keplerian
disc and inverse Comptonizes them to produce hard photons. The post-shock
region also produces jets. We study the interaction of both hard photons and
soft photons, with rotating electron-positron jets. We show that hard photons
from the post-shock torus are instrumental in acceleration of jets, while soft
photons from the Keplerian disc is a better collimating agent. We also show
that if the jets are launched closer to the black hole, relativistic and
collimated jets are produced; if they are launched at larger distances both
collimation and acceleration are less. We also show that if the shock location
is relatively at larger distances from the black hole, collimation is better.


title: Astrometric limits set by surface structure, binarity, microlensing

abstract:
  We give an assessment of the significance of various known effects which may
produce genuine fluctuations of star positions comparable to or larger than
Gaia's measurement noise, and which thus may limit the ultimately reachable
precision of the determination of parallaxes and proper motions. Stellar
granulation is found to be no problem except for a small number of cool
supergiants. It will be a serious problem for e.g. Mira star parallaxes. Star
spots are hard to assess quantitatively. They, too, may be problematic for
supergiants and very cool giants. Binarity is a major problem for the
astrometry of bright stars. It will significantly impair the kinematics of
stellar aggregates with small velocity dispersion. It will also produce a small
proportion of grossly wrong parallaxes. Gravitational microlensing will not be
a problem, although thousands of highly significant microlensing events will be
detected by Gaia. Gravitational macrolensing of quasars will add some noise to
their (otherwise ``zero'') proper motions.


title: Radiatively Driven Jets around Black Holes

abstract:
  The hot, puffed up, post-shock region of an advective disc is the source of
high energy photons and also the jets and outflows. We study the relativistic
equations of motion of jets as these high energy photons interact with them. We
show that the much discussed terminal velocity of jets depends on the
comparative value of radiative energy density, flux and the radiative pressure.
We show that electron-positron pair plasma jets achieves highly relativistic
terminal speeds for higher disc luminosities.


title: Gaia First Look

abstract:
  A complicated and ambitious space mission like Gaia needs a careful
monitoring and evaluation of the functioning of all components of the
satellite. This has to be performed on different time scales, by different
methods, and on different levels of precision. On the basis of housekeeping
data a Quick Look will be performed by the ground segment. A first analyses of
the science data quality and consistency will be done by a Science Quick Look.
However, due to the nominal scanning law a full self-consistent calibration of
the satellite, and a determination of astrometric and global parameters, is not
possible before about half a year has elapsed, imposing a serious danger to
lose valuable observing time if something goes wrong. Therefore, it is
absolutely necessary to perform a Detailed First Look on a daily basis on the
$\mu$as accuracy level. We describe two different methods, a block iterative
procedure and a direct solution, to monitor all satellite parameters that in
principle can be evaluated within a short amount of time, particularly those
that can be measured in along-scan direction. This first astrometric analysis
would greatly benefit from a modified scanning law (Zero-nu-dot mode) for some
time during the commissioning phase.


title: Predictions of the disc instability model

abstract:
  Confronting the predictions of numerical calculations with observations is an
important tool to progress with our understanding of the mechanism triggering
the outbursts of dwarf novae and soft X-ray transients. Simultaneous
multi-wavelength observations are of particular importance in this process as
they contain information about the chronology of the outbursts as e.g. the
famous UV-delay observed in dwarf novae. We review key-predictions of the disc
instability model (DIM) and confront them with the corresponding observations.


title: Modelling the Galaxy for GAIA

abstract:
  Techniques for the construction of dynamical Galaxy models should be
considered essential infrastructure that should be put in place before GAIA
flies. Three possible modelling techniques are discussed. Although one of these
seems to have significantly more potential than the other two, at this stage
work should be done on all three.
  A major effort is needed to decide how to make a model consistent with a
catalogue such as that which GAIA will produce. Given the complexity of the
problem, it is argued that a hierarchy of models should be constructed, of ever
increasing complexity and quality of fit to the data. The potential that
resonances and tidal streams have to indicate how a model should be refined is
briefly discussed.


title:
Binaries, cluster dynamics and population studies of stars and stellar
  phenomena

abstract:
  The effects of binaries on population studies of stars and stellar phenomena
have been investigated over the past 3 decades by many research groups. Here we
will focus mainly on the work that has been done recently in Brussels and we
will consider the following topics: the effect of binaries on overall galactic
chemical evolutionary models and on the rates of different types of supernova,
the population of point-like X-ray sources where we distinguish the standard
high mass X-ray binaries and the ULXs, a UFO-scenario for the formation of
WR+OB binaries in dense star systems. Finally we critically discuss the
possible effect of rotation on population studies.


title: Red thick disks of nearby galaxies

abstract:
  Edge on systems reveal the properties of disk galaxies as a function of
height, z, above the plane. Four local edge-on galaxies, that are close enough
to have been resolved into stars by the Hubble Space Telescope, show thick
disks, composed of a red stellar population, which is old and relatively metal
rich. Color gradients, d(V-I)/dz, are zero or slightly positive. Favored models
may have an explicit thick disk formation phase.


title:
XMM-Newton observations of the heavily absorbed Seyfert 1 galaxy IC
  4329A

abstract:
  We detect seven distinct absorbing systems in the high-resolution X-ray
spectrum of the Seyfert 1 galaxy IC 4329A, taken with XMM-Newton. Firstly we
detect absorption due to cold gas in our own Galaxy and warm gas in the
Galactic halo or the Local Group. This local warm gas is only detected through
O VII absorption, from which we deduce a temperature between 0.03 and 0.2 keV.
In IC 4329A we detect absorption from the host galaxy as well as from a warm
absorber, close to the nucleus, which has 4 components. The absorption from the
host galaxy is well modeled by neutral material. The warm absorber detected in
IC 4329A is photoionized and has an ionization range between log $\xi$ = -1.37
and log $\xi$ = 2.7. A broad excess is measured at the O VIII Ly$\alpha$ and N
VII Ly$\alpha$ emission lines, which can be modeled by either disklines or
multiple Gaussians. From the lightcurve we find that the source changed
luminosity by about 20 % over the 140 ks observation, while the spectral shape,
i.e. the softness ratio did not vary. In the EPIC spectra a narrow Fe K$\alpha$
and Fe XXVI Ly$\alpha$ emission line are detected. The narrowness of the Fe
K$\alpha$ line and the fact that there is no evidence for flux variability
between different observations leads us to conclude that the Fe K$\alpha$ line
is formed at a large distance from the central black hole.


title:
An Absence of Hot Jupiter Planets in 47 Tucanae: Results of a Wide-Field
  Transit Search

abstract:
  We present the results of a comprehensive wide field search for transiting
``Hot Jupiter'' planets (1d<P<16d) in the globular cluster 47 Tucanae.
Motivated by the core null result of Gilliland and coworkers, this work further
addresses the question of giant planet frequency in 47 Tuc by observing, from
the ground, a 52'x52' field centered on the cluster for 30.4 nights. Hence this
work is most sensitive to the uncrowded outer regions of the cluster and
concentrates on 21,920 main sequence stars (~solar in mass). This work
comprises the largest ground-based transit search of a globular cluster to
date.
  Monte Carlo simulations predict that seven planets should be present in our
dataset, if 47 Tuc has the same planetary frequency observed in the solar
neighbourhood. A detailed search with a custom developed detection algorithm
found no transit events. Being consistent with the cluster core null detection
of Gilliland and coworkers, our result indicates that system metallicity is the
dominant effect inhibiting Hot Jupiter formation in this environment.


title:
A Method for the Detection of Planetary Transits in Large Time-Series
  Datasets

abstract:
  We present a fast, efficient and easy to apply computational method for the
detection of planetary transits in large photometric datasets. The code has
been specifically produced to analyse an ensemble of 21,950 stars in the
globular cluster 47 Tucanae, the results of which are the subject of a separate
paper. Using cross correlation techniques and Monte Carlo tested detection
criteria, each time-series is compared with a large database of appropriate
transit models. The algorithm recovers transit signatures with high efficiency
while maintaining a low false detection probability, even in noisy data.
  This is illustrated by describing its application to our 47 Tuc dataset, for
which the algorithm produced a weighted mean transit recoverabilty spanning 85%
to 25% for orbital periods of 1-16 days despite gaps in the time series caused
by weather and observing duty cycle. The code is easily adaptable and is
currently designed to accept time-series produced using Difference Imaging
Analysis.


title: Toward Understanding Environmental Effects in SDSS Clusters

abstract:
  We find clusters and superclusters of galaxies using the Data Release 1 of
the Sloan Digital Sky Survey. We determine the luminosity function of clusters
and find that clusters in a high-density environment have a luminosity a factor
of ~5 higher than in a low-density environment. We also study clusters and
superclusters in numerical simulations. Simulated clusters in a high-density
environment are also more massive than those in a low-density environment.
Comparison of the density distribution at various epochs in simulations shows
that in large low-density regions (voids) dynamical evolution is very slow and
stops at an early epoch. In contrast, in large regions of higher density
(superclusters) dynamical evolution starts early and continues until the
present; here particles cluster early, and by merging of smaller groups very
rich systems of galaxies form.


title: From Radio to X-ray: Flares on the dMe Flare Star EV Lacertae

abstract:
  We present the results of a campaign to observe flares on the M dwarf flare
star EV Lacertae over the course of two days in 2001 September, utilizing a
combination of radio continuum, optical photometric and spectroscopic,
ultraviolet spectroscopic, and X-ray spectroscopic observations, to
characterize the multi-wavelength nature of flares from this active, single
late-type star. We find flares in every wavelength region in which we observed.
In the multi-wavelength context, the start of the intense radio flare is
coincident with an impulsive optical U-band flare, to within one minute, and
yet there is no signature of an X-ray response. There are other intervals of
time where optical flaring and UV flaring is occurring, but these cannot be
related to the contemporaneous X-ray flaring: the time-integrated luminosities
do not match the instantaneous X-ray flare luminosity, as one would expect for
the Neupert effect. We investigate the probability of chance occurrences of
flares from disparate wavelength regions producing temporal coincidences, but
find that not all the flare associations can be explained by a superposition of
flares due to a high flaring rate. We caution against making causal
associations of multi-wavelength flares based solely on temporal correlations
for high flaring rate stars like EV Lac.


title: Isotropy of the early universe from CMB anisotropies

abstract:
  The acoustic peak in the CMB power spectrum is sensitive to causal processes
and cosmological parameters in the early universe up to the time of last
scattering. We provide limits on correlated spatial variations of the peak
height and peak position and interpret these as constraints on the spatial
variation of the cosmological parameters (baryon density, cold dark matter
density and cosmological constant as well as the amplitude and tilt of the
original fluctuations). We utilize recent work of Hansen, Banday and Gorski
(HBG) who have studied the spatial isotropy of the power spectrum as measured
by WMAP by performing the power spectrum analysis on smaller patches of the
sky. We find that there is no statistically significant correlated asymmetry of
the peak. HBG have also provided preliminary indications of a preferred
direction in the lower angular momentum range(~ 2-40) and we show how possible
explanations of this asymmetry are severely constrained by the data on the
acoustic peak. Finally we show a possible non-gaussian feature in the data,
associated with a difference in the northern and southern galactic hemispheres.


title: Decay properties of the X-ray afterglows of Gamma-ray bursts

abstract:
  We present a set of seventeen Gamma-Ray Bursts (GRBs) with known redshifts
and X-ray afterglow emission. We apply cosmological corrections in order to
compare their fluxes normalized at a redshift of 1. Two classes of GRB can be
defined using their X-ray afterglow light curves. We show that the brightest
afterglows seem to decay faster than the dimer ones. We also point out
evidences for a possible flux limit of the X-ray afterglow depending on the
time elapsed since the burst. We try to interpret these observations in the
framework of the canonical fireball model of GRB afterglow emission.


title:
Limits on the Transverse Velocity of the Lensing Galaxy in Q2237+0305
  from the Lack of Strong Microlensing Variability

abstract:
  We present a method for the determination of upper limits on the transverse
velocity of the lensing galaxy in the quadruple quasar system Q2237+0305, based
on the lack of strong microlensing signatures in the quasar lightcurves. The
limits we derive here are based on four months of high quality monitoring data,
by comparing the low amplitudes of the lightcurves of the four components with
extensive numerical simulations. We make use of the absence of strong
variability of the components (especially components B and D) to infer that a
"flat" time interval of such a length is only compatible with an effective
transverse velocity of the lensing galaxy of v_bulk <=630 km/s for typical
microlenses masses of M_microlens=0.1 M_solar (or v_bulk <=2160 km/s for
M_microlens=1.0 M_solar) at the 90% confidence level. This method may be
applicable in the future to other systems.


title: Standard model atmospheres for A-type stars and non-LTE effects

abstract:
  The current status of NLTE model atmosphere calculations of A type stars is
reviewed. During the last decade the research has concentrated on solving the
restricted NLTE line formation problem for trace elements assuming LTE model
atmospheres. There is a general lack of calculated NLTE line blanketed model
atmospheres for A type stars, despite the availability of powerful methods and
computer codes that are able to solve this task. Some directions for future
model atmosphere research are suggested.


title:
Abundances of C, N, O in slightly evolved stars in the globular clusters
  NGC 6397, NGC 6752 and 47 Tuc

abstract:
  Abundances of C and N are derived from features due to the CH G-band and to
the UV CN band measured on high resolution (R ~ 40,000) UVES spectra of more
than 40 dwarfs and subgiants in NGC 6397, NGC 6752 and 47 Tuc. Oxygen
abundances (or upper limits) are available for all stars in the sample.
Isotopic ratios 12C/13C were derived from the CH molecular band. This is the
first determination of this ratio in unevolved dwarf stars in globular
clusters. By enlarging the sample of subgiants in NGC 6397 studied in Gratton
et al. (2001), we uncovered, for the first time, large variations in both Na
and O also in this cluster. The origin of the chemical inhomogeneities must be
searched for outside the stars under scrutiny. Our data indicate that in
unevolved or slightly evolved stars in these clusters C abundances are low but
not zero, also in stars with large N-enhancements and O-depletions, and that
the isotopic ratios 12C/13C are low, but never reach the equilibrium value of
the CN-cycle. When coupled with the run of O and Na abundances, these findings
possibly require that, in addition to CNO burning and p-captures, some
triple-alpha process is also involved: previously evolved intermediate-mass AGB
stars are then the most likely polluters.


title:
Pulsar Kicks Induced by Spin Flavor Oscillations of Neutrinos in
  Gravitational Fields

abstract:
  The origin of pulsar kicks is reviewed in the framework of the spin-flip
conversion of neutrinos propagating in the gravitational field of a magnetized
protoneutron star. We find that for a mass in rotation with angular velocity
${\bbox \omega}$, the spin connections entering in the Dirac equation give rise
to the coupling term ${\bbox \omega}\cdot {\bf p}$, being ${\bf p}$ the
neutrino momentum. Such a coupling can be responsible of pulsar kicks owing to
the neutrino emission asymmetry generated by the relative orientation of ${\bf
p}$ with respect to ${\bbox \omega}$. For our estimations, the large non
standard neutrino magnetic momentum, $\mu_\nu \lesssim 10^{-11}\mu_B$, is
considered.


title: The Chandra X-Ray Observatory: Observations of Neutron Stars

abstract:
  We present here an overview of the status of the Chandra X-ray Observatory
which has now been operating for five years. The Observatory is running
smoothly, and the scientific return continues to be outstanding. We provide
some details on the molecular contamination of the ACIS filters and its impact
on observations. We review the observations with Chandra of the pulsar in the
Crab Nebula and add some general comments as to the analysis of X-ray spectra.
We conclude with comments about the future directions for the study of neutron
stars with Chandra.


title:
Constraints on Field Galaxy Halos from Weak Lensing and Satellite
  Dynamics

abstract:
  Here I summarize constraints on the nature of the dark matter halos of field
galaxies that have been obtained from the most recent investigations of (i)
weak galaxy-galaxy lensing and (ii) the dynamics of satellite galaxies in orbit
about large host galaxies. Both of these techniques are statistical in their in
their nature (i.e., large samples of galaxies are required to obtain a
"signal"), but since they have inherently different selection biases and
systematic errors they are quite complementary to each other. Results of work
over the last several years on weak lensing and satellite dynamics is revealing
a remarkably consistent picture regarding the dark matter halos of bright field
galaxies (L > L*). The halos extend to large physical radii (> 150 kpc/h) and
are flattened in projection on the sky, there is a marked difference in the
depths of the potential wells of early-type galaxies and late-type galaxies,
and the velocity dispersion profiles of the halos decrease at large projected
radii. All of these are expected to hold true in a cold dark matter universe
and, while neither technique can address the the possible small-scale conflicts
between CDM and observed galaxies, on scales > 50 kpc/h both techniques yield
results that are consistent with each other and with the predictions of CDM.


title: The Recurrent Nature of Central Starbursts

abstract:
  New hydrodynamic models with feedback show that feedback driven turbulence
and subsequent relaxation can drive recurrent starbursts, though most of these
bursts fizzle due to premature, asymmetric ignition. Strong bursts are
terminated when the turbulence inflates the multiphase central disk. The period
between bursts is about twice a free-fall time onto the central disk. Transient
spirals and bars are common through the burst cycle.


title:
Boron Depletion in F and G Dwarf Stars and the Beryllium-Boron
  Correlation

abstract:
  Boron provides a special probe below the stellar surface as it survives to
greater depths than do Li and Be. To search for B depletions we have observed B
in 13 F and G dwarfs with large Be depletions; for comparison we also obtained
spectra of five stars which are undepleted in Li and Be. We have used HST with
STIS to obtain spectra of the B I resonance line at 2497 \AA. The spectral
resolution is 30,000 or 114,000 and the median signal-to-noise ratio is 70 per
pixel. New Be and Li spectra have been obtained at Keck I with HIRES of four of
the five standard stars at $\sim$48,000 resolution. Abundances have been
determined by the spectrum synthesis method with MOOG. A comparison between the
standard stars and those with severe Be depletions shows a distinct difference
in the B abundances between the two groups of 0.22 dex. We have discovered a
correlation between the Be and B abundances. The slope between A(Be) and
A(B)$_{NLTE}$ is 0.22 $\pm$0.05 (where A(element) = log N(element)/N(H) +
12.00) which, as expected, is shallower than the slope between A(Li) and A(Be)
of 0.38. We have normalized the light element abundances to account for the
observation that the initial abundances are somewhat lower in lower metallicity
stars by employing recently published empirical relations between Be and [Fe/H]
and between B and [Fe/H] (Boesgaard et al). The correlation between the
normalized A(Be) and A(B)$_{NLTE}$ has a slope of 0.18 $\pm$0.06. The star with
the largest Be depletion, HR 107 a main sequence Ba star, also has the largest
B depletion with the B abundance lower by a factor of 3.5 relative to the
standard stars.


title:
Supermassive Black Holes in Galactic Nuclei: Past, Present and Future
  Research

abstract:
  This review discusses the current status of supermassive black hole research,
as seen from a purely observational standpoint. Since the early '90s, rapid
technological advances, most notably the launch of the Hubble Space Telescope,
the commissioning of the VLBA and improvements in near-infrared speckle imaging
techniques, have not only given us incontrovertible proof of the existence of
supermassive black holes, but have unveiled fundamental connections between the
mass of the central singularity and the global properties of the host galaxy.
It is thanks to these observations that we are now, for the first time, in a
position to understand the origin, evolution and cosmic relevance of these
fascinating objects.


title:
A hadronic synchrotron mirror model for the "orphan" TeV flare in 1ES
  1959+650

abstract:
  Very-high-energy gamma-ray flares of TeV blazars are generally accompanied by
simultaneous flaring activity in X-rays. The recent observations by the Whipple
collaboration of an ``orphan'' TeV flare of 1ES 1959+650 (without simultaneous
X-ray flare) is very hard to reconcile with the standard leptonic SSC model
which is routinely very successfully employed to explain the SED and spectral
variability of TeV blazars. In this paper, an alternative scenario is suggested
in which the ``orphan'' TeV flare may originate from relativistic protons,
interacting with an external photon field supplied by electron-synchrotron
radiation reflected off a dilute reflector. While the external photons will be
virtually ``invisible'' to the co-moving ultrarelativistic electrons in the jet
due to Klein-Nishina effects, their Doppler boosted energy is high enough to
excite the $\Delta$ resonance from relativistic protons with Lorentz factors of
~ 10^3 - 10^4. This model is capable of explaining the ``orphan'' TeV flare of
1ES 1959+650 with plausible parameters, thus constraining the number and
characteristic energy of relativistic protons in the jet of this blazar.


title: FUSE's Five Years of Progress on the Interstellar Medium

abstract:
  I review the five years of progress by FUSE on current topics in the
interstellar medium. FUSE's sensitivity and unique access to the far
ultraviolet allow investigators to solve problems in all phases of the
interstellar medium. I describe FUSE's contributions in four major areas: 1)
the Local Interstellar Medium (LISM), 2) the hot phase (O VI), 3) the cold
phase (H_2), and 4) interstellar gas abundances. I devote particular attention
to the common themes of ISM phase interactions and changes with metallicity. As
a whole, these results show that FUSE is the most powerful machine ever to
address problems of the ISM, and that FUSE points vividly to the future of ISM
studies in the Galaxy, Local Group, and beyond.


title:
Discovery of Two Gravitationally Lensed Quasars with Image Separations
  of 3 Arcseconds from the Sloan Digital Sky Survey

abstract:
  We report the discovery of two doubly-imaged quasars, SDSS
J100128.61+502756.9 and SDSS J120629.65+433217.6, at redshifts of 1.838 and
1.789 and with image separations of 2.86'' and 2.90'', respectively. The
objects were selected as lens candidates from the Sloan Digital Sky Survey
(SDSS). Based on the identical nature of the spectra of the two quasars in each
pair and the identification of the lens galaxies, we conclude that the objects
are gravitational lenses. The lenses are complicated; in both systems there are
several galaxies in the fields very close to the quasars, in addition to the
lens galaxies themselves. The lens modeling implies that these nearby galaxies
contribute significantly to the lens potentials. On larger scales, we have
detected an enhancement in the galaxy density near SDSS J100128.61+502756.9.
The number of lenses with image separation of ~3'' in the SDSS already exceeds
the prediction of simple theoretical models based on the standard
Lambda-dominated cosmology and observed velocity function of galaxies.


title:
Large-Amplitude Ultraviolet Variations in the RR Lyrae Star ROTSE-I
  J143753.84+345924.8

abstract:
  The NASA Galaxy Evolution Explorer (GALEX) satellite has obtained
simultaneous near and far ultraviolet light curves of the ROTSE-I Catalog RR
Lyrae ab-type variable star J143753.84+345924.8. A series of 38 GALEX Deep
Imaging Survey observations well distributed in phase within the star's
0.56432d period shows an AB=4.9mag variation in the far UV (1350-1750A) band
and an AB=1.8mag variation in the near UV (1750-2750A) band, compared with only
a 0.8mag variation in the broad, unfiltered ROTSE-I (4500-10000A) band. These
GALEX UV observations are the first to reveal a large RR Lyrae amplitude
variation at wavelengths below 1800A. We compare the GALEX and ROTSE-I
observations to predictions made by recent Kurucz stellar atmosphere models. We
use published physical parameters for the comparable period (0.57433d),
well-observed RR Lyrae star WY Antliae to compute predicted FUV, NUV, and
ROTSE-I light curves for J143753.84+345924.8. The observed light curves agree
with the Kurucz predictions for [Fe/H]=-1.25 to within AB=0.2mag in the GALEX
NUV and ROTSE-I bands, and within 0.5mag in the FUV. At all metallicities
between solar and one hundredth solar, the Kurucz models predict 6-8mag of
variation at wavelengths between 1000-1700A. Other variable stars with similar
temperature variations, such as Cepheids, should also have large-amplitude FUV
light curves, observable during the ongoing GALEX imaging surveys.


title:
Hybrid nature of 0846+51W1: a BL Lac object with a narrow line Seyfert 1
  nucleus

abstract:
  We have found a NLS1 nucleus in the extensively studied eruptive BL Lac,
0846+51W1, out of a large sample of NLS1 compiled from the spectroscopic
dataset of SDSS DR1. Its optical spectrum can be well decomposed into three
components, a power law component from the relativistic jet, a stellar
component from the host galaxy, and a component from a typical NLS1 nucleus.
The emission line properties of 0846+51W1, FWHM(Hbeta) ~ 1710 km s^-1 and
[OIII]5007/Hbeta ~ 0.32 when it was in faint state, fulfil the conventional
definition of NLS1. Strong FeII emission is detected in the SDSS spectrum,
which is also typical of NLS1s. We try to estimate its central black hole mass
using various techniques and find that 0846+51W1 is very likely emitting at a
few times 10% L_Edd. We speculate that Seyfert-like nuclei, including NLS1s,
might be concealed in a significant fraction of BL Lacs but have not been
sufficiently explored due to the fact that, by definition, the optical-UV
continuum of such kind of objects are often overwhelmed by the synchrotron
emission.


title: Observational constraints on generalized Chaplygin gas model

abstract:
  The generalized Chaplygin gas model with parameter space $\alpha>-1$ is
studied in this paper. Some reasonable physical constraints are added to
justify the use of the larger parameter space. The Type Ia supernova data and
age data of some clusters are then used to fit the model. We find that the
parameters have bimodal distributions. For the generalized Chaplygin gas model,
we also find that less free parameters fit the data better. The best fit model
is the spatially flat model with baryons. The best fit parameters are:
$\Omega_{m0}=0.044$, $w_{c0}=-0.881$ and $\alpha=1.57$. The transition redshift
is $z_T=0.395$.


title: 3D-simulation of the Outer Convection-zone of an A-star

abstract:
  The convection code of Nordlund & Stein has been used to evaluate the 3D,
radiation-coupled convection in a stellar atmosphere with Teff=7300K, logg=4.3
and [Fe/H]=0.0, corresponding to a main-sequence A9-star. I will present
preliminary comparisons between the 3D-simulation and a conventional 1D stellar
structure calculation, and elaborate on the consequences of the differences.