title: The Orion Nebula in the mid-IR

abstract:
  We present two wide-field (5'x5'), diffraction limited, broad-band 10 and 20
micron images of the Orion Nebula, plus six 7-13 micron narrow-band images of
BN/KL taken at the 3.8m UKIRT telescope. The wide-field images are mosaics of
35"x35" frames reconstructed using a new restoration method developed for this
project. They show the filamentary structure of the dust emission and reveal a
new remarkable group of arc-like structures ~1' to the South of the Trapezium.
The morphology of the Ney-Allen nebula suggests a complex kinematical status at
the center of the Cluster. We find indications that the B0.5V star theta1
Ori-D, is surrounded by a photoevaporated circumstellar disk. Among the four
historic Trapezium OB stars, this is the only one without a binary companion,
suggesting that stellar multiplicity and the presence of massive circumstellar
disks may be mutually exclusive. In the BN/KL complex we detect optically thin
silicate emission on top of the deep 10 micron absorption feature. We map the
foreground optical depth, color temperature and mid-IR luminosity of the
embedded sources. We resolve a conspicuous point source at the location of the
IRc2-A knot. The spectral profile of the 10 micron feature is compatible with
grain crystallization. We detect several point sources In the OMC-1 South
region and discuss their association with the mass loss observed at optical and
mm wavelengths. Finally, we list the position and photometry of 177 point
sources. With two possible exceptions, all point sources detected at shorter
wavelengths display 10 micron emission well above the photospheric level. The
model of Robberto et al. (2002, ApJ, 578, 897) provides the simplest
explanation for the mid-IR excess.


title:
Hydrodynamic and hydromagnetic energy spectra from large eddy
  simulations

abstract:
  Direct and large eddy simulations of hydrodynamic and hydromagnetic
turbulence have been performed in an attempt to isolate artifacts from real and
possibly asymptotic features in the energy spectra. It is shown that in a
hydrodynamic turbulence simulation with a Smagorinsky subgrid scale model using
512^3 meshpoints two important features of the 4096^3 simulation on the Earth
simulator (Kaneda et al. 2003, Phys. Fluids 15, L21) are reproduced: a k^{-0.1}
correction to the inertial range with a k^{-5/3} Kolmogorov slope and the form
of the bottleneck just before the dissipative subrange. Furthermore, it is
shown that, while a Smagorinsky-type model for the induction equation causes an
artificial and unacceptable reduction in the dynamo efficiency,
hyper-resistivity yields good agreement with direct simulations. In the
large-scale part of the inertial range, an excess of the spectral magnetic
energy over the spectral kinetic energy is confirmed. However, a trend towards
spectral equipartition at smaller scales in the inertial range can be
identified. With magnetic fields, no explicit bottleneck effect is seen.


title:
Halo Luminosity Function From Photometric Calibration of the Revised
  NLTT

abstract:
  We calibrate the photographic photometry of the revised New Luyten Two-Tenths
catalog (rNLTT) by matching 3448 rNLTT stars to the Sloan Digital Sky Survey
(SDSS). The correction is linear in magnitude and goes from zero at V ~ 14 to
0.32 mag at V=19, in the sense that rNLTT was previously too bright. The
correction implies that the underlying USNO-A2.0 photometry, on which rNLTT
photometry is based, is non-linear. The new calibration somewhat improves the
appearance of the (V,V-J) reduced proper motion diagram in the sense of better
separation between disk and halo stars. We repeat Gould's analysis of 5000 halo
stars in rNLTT. The most important change is to move the peak of the halo
luminosity function about 0.5 mag dimmer, from M_V=10.5 to M_V=11, putting it
into good agreement with the parallax-based determination of Dahn et al.


title:
Cool Customers in the Stellar Graveyard I: Limits to Extrasolar Planets
  Around the White Dwarf G29-38

abstract:
  We present high contrast images of the hydrogen white dwarf G 29-38 taken in
the near infrared with the Hubble Space Telescope and the Gemini North
Telescope as part of a high contrast imaging search for substellar objects in
orbit around nearby white dwarfs.
  We review the current limits on planetary companions for G29-38, the only
nearby white dwarf with an infrared excess due to a dust disk. We add our
recent observations to these limits to produce extremely tight constraints on
the types of possible companions that could be present. No objects $>$ 6
M$_{Jup}$ are detected in our data at projected separations $>$ 12 AU, and no
objects $>$ 16 M$_{Jup}$ are detected for separations from 3 to 12 AU, assuming
a total system age of 1 Gyr. Limits for companions at separations $<$ 3 AU come
from a combination of 2MASS photometry and previous studies of G29-38's
pulsations. Our imaging with Gemini cannot confirm a tentative claim for the
presence of a low mass brown dwarf. These observations demonstrate that a
careful combination of several techniques can probe nearby white dwarfs for
large planets and low mass brown dwarfs.


title:
Cool Customers in the Stellar Graveyard II: Limits to Substellar Objects
  Around Nearby DAZ White Dwarfs

abstract:
  Results from a concerted Hubble Space Telescope (HST) survey of nearby white
dwarfs for substellar objects is presented. A total of 7 DAZ white dwarfs with
distances of $<$ 50 pc had high contrast and high spatial resolution NICMOS
coronagraphic images taken to search for candidate substellar objects at
separations $\ltorder$10\arcsec away. Limits to unresolved companions are
derived through analysis of 2MASS photometry of the white dwarfs compared to
expected fluxes based on the WDs effective temperature, distance, and gravity.
  From our survey with HST we find several candidate companions, which have
been or will be followed up with second epoch observations. We find that for
four of the white dwarfs we are sensitive to planetary companions $\gtorder$10
M$_{Jup}$, and sensitive to companions $>$ 18 M$_{Jup}$ for all of the targets.
The lack of significant near infrared excesses for our targets limits any kind
of unresolved companions present to be substellar. In light of these results we
make several comments on the possibility of determining the origin of white
dwarfs with metals in their atmospheres.


title: Chandra Studies of Millisecond Pulsars in Globular Clusters

abstract:
  The high resolution X-ray imaging and broad-band moderate resolution spectra
enabled by the ACIS cameras on the Chandra X-ray Observatory have opened a new
window in our study of millisecond pulsars (MSPs). Given the large excess of
MSPs in globular clusters vs. the field, globular clusters are the favored
sites for MSP study. Globular clusters (GCs) offer advantages of both known
distance and likely MSP formation mechanisms but are complicated (or made more
interesting!) by the complexities of subsequent MSP dynamical interactions.
Here I review recent X-ray studies, focusing on our recent deep Chandra study
of 47Tuc, which provide new constraints on both the spectra (thermal and non
thermal) and evolution of MSPs and their encounters with both cluster and field
stars.


title: How Dark is 'Dark'? Electromagnetic Interactions in the Dark Sector

abstract:
  We review the physical and cosmological consequences of two possible
electromagnetic couplings to the dark sector: (i) a neutral lightest
dark-matter particle (LDP) with nonzero electric and/or magnetic dipole moments
and (ii) a charged next-to-lightest dark-matter particle (NLDP) which decays to
a neutral LDP. For scenario (i) we find that a relatively light particle with
mass between a few MeV and a few GeV and an electric or magnetic dipole as
large as $\sim 3\times 10^{-16}e$ cm (roughly $1.6\times10^{-5} \mu_B$)
satisfies experimental and observational bounds. In scenario (ii), we show that
charged-particles decaying in the early Universe result in a suppression of the
small-scale matter power spectrum on scales that enter the horizon prior to
decay. This leads to either a cutoff in the matter power spectrum, or if the
charged fraction is less than unity, an effect in the power spectrum that might
resemble a running (scale-dependent) spectral index in small-scale data.


title: Bulk Compton Emission in the GRB Internal Shock Model

abstract:
  We investigate the role of the bulk Compton-scattering process in the
internal shock model. We numerically show that the radiation field created by
internal shocks does not affect the efficiency of the energy conversion in the
shocks even if fireball outflows have highly nonuniform velocity distributions.
However, the bulk Compton-scattering produces an additional high energy
component especially when variability in the outflows arises because of a
modulation of the mass injected into a constant energy flow. We show that an
isotropic energy of $10^{50-51}$ ergs could be radiated in the range of
100MeV-GeV through the scattering process, provided that the shell's Lorentz
factor varies between 10 and $10^4$.


title: OH in Messier 82

abstract:
  Several new main line OH masers have been detected in the nearby starburst
galaxy M82. Eight masers have been detected to 5 sigma, six of which are new
detections. Observations covering both the 1665 and 1667 MHz lines with both
the Very Large Array (VLA) and the Multi-Element Radio Linked Interferometer
Network (MERLIN) have been used to accurately measure the positions and
velocities of these features. Following analysis of the data, another six
objects below 5 sigma, but with velocities consistent with the distribution
inferred from the more certain detections, have been detected. These are
classified as possible detections.


title: Multi-Frequency VLBI Observations of GHz-Peaked Spectrum Sources

abstract:
  We report results of pentachromatic VLBI survey for 18 GHz-peaked spectrum
sources. Spectral fitting at every pixel across five frequencies allows us to
illustrate distribution of optical depth in terms of free-free absorption or
synchrotron self absorption. Quasars and Seyfert 1 sources show one-sided
morphology with a core at the end where the optical depth peaks. Radio galaxies
and Seyfert 2 show symmetric double-sided jets with a optically thick core at
the center.


title: The simultaneous VLA observations of Sgr A* from 90 to 0.7 cm

abstract:
  We present a spectrum of Sgr A* observed simultaneously on June 17, 2003 at
wavelengths from 90 to 0.7 cm with the VLA. In the spectrum, we also include
the measurements of Sgr A* observed on the same day with the GMRT at 49 cm, the
SMA at 0.89 mm and the Keck II at 3.8 $\mu$m. The spectrum at the centimeter
wavelengths suggests the presence of a break wavelength at 3.8 cm (8 GHz). The
spectral index is alpha=0.43+-0.03 (propto nu(alpha}) at 3.8 cm and shorter
wavelengths. The spectrum between 3.8 cm and 49 cm can be described by a power
law with spectral index of alpha=0.10+-0.03$. We detected Sgr A* with
0.22+-0.06 Jy at 90 cm, suggesting a sharp decrease in flux density at the
wavelengths longer than 49 cm. The best fit to the spectrum at the wavelengths
longer than lambda_b appears to be consistent with free-free absorption by a
screen of ionized gas with a turnover wavelength at nu(tau_ff}=1) = 100 cm (300
MHz). This turnover wavelength appears to be three times longer than that of 30
cm (1 GHz) as suggested by Davies et al. (1976) based on the observations in
1994 and 1995. Our analysis suggests that stellar winds from the massive stars
near Sgr A* could modulate the flux density at the wavelengths longer than 30
cm (or frequencies below 1 GHz).


title: LFVN observations of active galactic nuclei

abstract:
  In November 1999 we carried out VLBI observations of several quasars and BL
Lacertae objects at 1.66 GHz. Six antennas participated in the experiment (Bear
Lakes, Svetloe, Pushchino, Noto, HartRAO, and Seshan). The results for six
sources (0420+022, 0420-014, 1308+326, 1345+125, 1803+784, and DA193) are
presented and discussed.


title: EVN observations of the lens system B0128+437

abstract:
  Previous VLBI observations of the lens system CLASS B0128+437 showed that the
lensed source had a triple sub-component structure. However, one of the images
looked very different to the others and it has been suggested that this is due
to scatter-broadening in the ISM of the lensing galaxy. We present a new 21-cm
EVN map of this system, the low frequency compared to previous epochs chosen as
the scattering should be more pronounced at this frequency. Analysis of the new
map is at an early stage, but the area of scattering in the affected image is
extremely obvious. Other points of interest that we seek to explain are the
very large sizes of the images (in conflict with the observed spectral turnover
at about 1 GHz) and the different position angle of one of the images at
different frequencies.


title: A VLBI Study of the Gravitational Lens JVAS B0218+357

abstract:
  We present the results of phase-referenced VLBA+Effelsberg observations at
five frequencies of the gravitational lens B0218+357 to establish the precise
registration of the A and B lensed image positions.


title: MERLIN 6-GHz maser emission from W3(OH)

abstract:
  We present the preliminary results of the first alignment to milliarsecond
accuracy of the 6 GHz maser emission in OH and methanol maser lines toward
W3(OH). The identifications of Zeeman pairs allowed us to infer the actual
velocity of the OH material and the magnetic field strength at the location
where 6.7 GHz methanol maser emission arises.


title:
Observations of H2O maser sources in Orion-Monoceros Molecular Clouds
  with VERA

abstract:
  We present results of phase-referencing VLBI observations of water maser
sources in Orion-Monoceros Molecular Clouds with VERA (VLBI Exploration of
Radio Astrometry), which is newly constructed Japanese VLBI network. Main
topics of this poster are (1) the aim of one of the first scientific projects
for VERA "3-Dimensional Structure and Kinematics of Orion-Monoceros Molecular
Cloud Complex"; (2) current status (sensitivity and astrometric accuracy) of
phase-referencing VLBI observations with VERA; and (3) results of VLBI
observations of water sources in Orion-Monoceros Molecular Clouds with VERA.


title: Astrometry of W49N - OH43.8-0.1 H2O maser pair with VERA

abstract:
  We present the results of multi-epoch VERA observations of W49N - OH43.8-0.1
water maser pair. Based on the dual-beam VLBI observation with VERA, we
successfully obtained the phase-referenced maps of OH43.8-0.1 with respect to
the W49N reference spot for 3 epochs with a time span of 6 months. The maps
were in good agreement with previous studies obtained with a single-beam VLBI,
and were also consistent with each other with an accuracy of about 0.2 mas.
Moreover, there are systematic, rather linear displacements of maser feature
positions, which may be the relative proper motions of maser features caused by
the Galactic rotation as well as internal motions of individual maser features.


title: Probing the polarization characteristics of SS433 on mas scales

abstract:
  We present a status report of dedicated circular polarization (CP) global
VLBI observations of SS433. The total intensity image of the source is
presented. We do not detect linear polarization in the core region of the
source. We estimate the errors in D-terms for the EVN, and its effect on the
final right-left circular polarization gain calibration. The data from this and
earlier observations are analyzed with the "zero-V" self-calibration technique,
in order to obtain indications for detectable CP in different regions of the
source. Our data show no evidence for strong gyro-synchrotron (GS) emission on
the size scale probed by our beam.


title: Microquasar Observations with MERLIN

abstract:
  A series of observations of microquasar GRS1915+105 were made by the MERLIN
telescope array in the spring of 2003 at 18 cm. The images show polarization in
the jet components, with two epochs displaying Faraday rotation of about 2500
rad/m2. This effect is a demonstration of the similarities between microquasars
and extragalactic jets.


title: Recent Results from the EVN MkIV Data Processor at JIVE

abstract:
  Recent achievements at the EVN MkIV data processor at JIVE include decreasing
the read-out time for the whole correlator to 0.25 seconds (or 0.125 s for half
the correlator), improving the end quality of user data (e.g., applying an
improved 2-bit van Vleck correction), developing new astronomical capabilities
(e.g., oversampling to x 4, wider-field mapping), and strengthening liaison
procedures with PIs (e.g., pipelining, the EVN Archive facility). At the same
time, the move to a disk-based EVN and regular incorporation of FTP
fringe-checks is well underway, resulting in more reliable data quality. We
will review these developments, highlighting how they may broaden the kinds of
astronomy you can do. We'll also go over some measures you can take to help you
get the most out of these new/improved features.


title: The Australian experience with the PC-EVN recorder

abstract:
  We report on our experiences using the Metsahovi Radio Observatory's (MRO)
VLBI Standard Interface (VSI, Whitney 2002) recorder in a number of
astronomical applications. The PC-EVN device is a direct memory access (DMA)
interface which allows 512 megabit per second (Mbps) or better recording to
"off the shelf" PC components. We have used this setup to record at 640 Mbps
for a pulsar coherent dispersion system and at 256 Mpbs for a global VLBI
session. We have also demonstrated recording at 512 Mbps and will shortly form
cross correlations between the CPSR-II and the PC-EVN systems.


title: From truck to optical fibre: the coming-of-age of eVLBI

abstract:
  Spurred by the advent of disk-based recording systems and the nearly
explosive increase of internet bandwidth, eVLBI (Parsley et al. 2004) has
undergone a remarkable development over the past two years. From ftp-based
transfers of small amounts of astronomical data, through near real-time
correlation (disk-buffered at the correlator), it has culminated this spring in
the first three telescope real-time correlation at JIVE (Onsala, Westerbork and
Jodrell Bank). In this paper we will give a review of this development and the
current state of affairs. We will also address the current limitations and the
way we may improve both bandwidth and reliability and finally we will discuss
the opportunities a true high-bandwidth real-time VLBI correlator will provide.


title:
What is the primary beam response of an interferometer with unequal
  elements?

abstract:
  The EVN stations encompass elements with a range of diameters, even including
an interferometer (the Westerbork Telescope, with up to 14 elements used
together as a tied array). In combination, the various station pairs will each
produce their own primary beam envelopes, with which the interferometer pattern
is modulated. People sometimes forget that in the case of unequal elements,
this combined primary beam envelope is different from the beam of each element
separately. The reason for this is reviewed, the results for a number of
station pairs are summarized, and some of the practical consequences are
discussed. The increased interest in wide-field applications, as illustrated by
several recent results, underlines the need for a proper determination of the
interferometer beam envelope.


title: East Asian VLBI Activities

abstract:
  The VLBI activities in the East Asia region are planning to coordinate among
VLBI groups and institutes in China, Japan, and Korea. In these countries, some
new projects are going to start or discussed, and some types of collaboration
have been already done individually. These new projects are briefly introduced.
Under these circumstances, an organization has been discussed for the
coordinated efforts to produce fruitful results more effectively.


title: Construction of the Korean VLBI Network (KVN)

abstract:
  Korea's new VLBI project to construct the Korean VLBI Network (KVN) started
in 2001, as a 7-year project that is fully funded by our government. We plan to
build 3 new high-precision radio telescopes of 21-m diameter in 3 places in
Korea, which will be exclusively used for VLBI observations. We will install
the 2/8, 22 and 43 GHz HEMT receivers within 2007 as a first target, and later
we will expand the receiving frequency up to 86 and 129 GHz for astronomical,
geodetic, and earth science VLBI research. The millimeter-wave VLBI will be the
ultimate goal of KVN. For the front-ends, we are going to install a
multi-channel receiver system that employs low-pass filters within a
quasi-optical beam transportation system. This receiver system will give
reliable phase calibrations for millimeter-wave VLBI as well as enable
simultaneous multi-frequency band observations. The hard-disk type new Mark 5
will be used as the main recorder of KVN. We have completed the design of the
KVN DAS system of 2 Gsps sampling rate, which will use 4 data streams to meet
the multi-channel requirement. A VERA type DAS modified for Mark 5 recorder is
also under consideration. A new correlator project for KVN was recently
approved from Korean government, and will start in the second half of 2004.


title: Spacecraft Design of VSOP-2

abstract:
  As presented by Hirabayashi et al. (2004) these proceedings, the VSOP-2
mission is currently being planned. Various kinds of developments are being
made for the misson, and here we introduce the large antenna, fast switching
scheme using CMG, low noise receivers, gigabit data transmission, and high data
rate sampling on-board. We are also studying the system configuration of the
VSOP-2 satellite and the orbit appropriate for the expected launch vehicle, the
M-V rocket. VSOP-2 science goals include imaging the accretion disks around the
massive blackholes in the nuclei of the active galaxies, studies of magnetic
field orientation and evolution in jets, and the highest resolution studies of
spectral line masers and mega-masers. Here we describe the design and the
development of the space antenna, high speed sampler, and the satellite system.


title: VSI-E Software Suite

abstract:
  As broadband access to high speed research and education networks has become
increasingly available to radio telescopes around the world the use of e-VLBI
has also increased. High bandwidth e-VLBI experiments have been achieved across
wide areas (Whitney et al., 2003). e-VLBI has also been used for the transfer
of data from "production" experiments. As the use of e-VLBI becomes more and
more prevalent, the need to have some form of standard framework for
facilitating interoperability between various acquisition, transport and
processing systems around the world is becoming increasingly important. This is
the motivation behind the VLBI Standard Interface - Electronic (VSI-E)
standard. VSI-E is currently in draft form [\cite{bib-vsie}] and is going
through the standards process within the VLBI community. In this poster, we
describe an initial reference implementation of the VSI-E protocol. The
implementation has been done using the C/C++ language and is in the form of a
re-useable library. It has been developed on the Linux platform and can be
easily ported to most POSIX-compliant platforms. The reference implementation
also includes a high-performance application level transport protocol. That can
be used to transport data within the framework of VSI-E.


title: How to improve the High Frequency capabilities of SRT

abstract:
  The SRT (Sardinia Radio Telescope) is a general purpose, fully steerable,
active surface equipped, 64 meters antenna, which is in an advanced
construction state near Cagliari (Sardinia - Italy). It will be an antenna
which could improve a lot the performances of the EVN network, particularly at
frequencies higher than 22 GHz. The main antenna geometry consist of a shaped
reflector system pair, based on the classical parabola-ellipse Gregorian
configuration. It is designed to be able to operate with a good efficiency in a
frequency range from 300 MHz up to 100 GHz. This frequency range, is divided in
two parts which define also two antenna operational modes, one up to 22 GHz
with a minimal amount of accessory instrumentation, and the other up to 100 GHz
with a full complement of instrumentation. The goal is to make it possible to
build a telescope operable up to 22 GHz, and then upgrade it at a future date
to operate at frequencies up to 100 GHz. In order to get these goals, the SRT
Metrology group is studying and developing different types of strategies,
instrumentation, and techniques for measuring and reducing the various
components of pointing and efficiency errors, taking advantage also from
experiences developed in other radio telescopes, like GBT (Green Bank
Telescope, USA), LMT (Large Millimiter Telescope, MEX), and IRAM (Institut de
Radio Astronomie Millimetrique, Fr). Many of those system will be installed and
tested at the 32 meters radio-telescope in Medicina (Bologna), before of their
implementation on SRT.


title: IVS Products for Precise Global Reference Frames

abstract:
  VLBI plays a unique and fundamental role in the maintenance of global
reference frames which are required for precise positioning in many research
areas related e.g to the understanding and monitoring of global changes, to
geodesy, to space missions etc. The International VLBI Service for Geodesy and
Astrometry coordinates internationally the VLBI components and resources and is
tasked by IAG and IAU for the provision of products describing the Celestial
Reference Frame through positions of quasars and their changes with time and
also for products describing the rotation of the Earth in space. This paper
summarises today's status of the products, achieved over the last years by
evolving the observing programs. It points out the activities to improve
further on the product quality to meet future service requirements, which will
come up with the need for highly precise global reference frames.


title: First results of European VLBI radar observations of space objects

abstract:
  Since 1999 we carried out seven trial VLBI radar experiments under LFVN
project. The aim of this work is to adjust new research technique for
investigating the Solar system bodies (planets, asteroids, space debris). It is
planned to obtain the information on their movement parameters, proper rotation
and structure of surface. The transmitter of Evpatoria RT-70 sounded the space
objects. Array of Bear Lakes RT-64, Noto RT-32, Urumqi RT-25, Simeiz RT-22
received the echo-signals. The data were processed with NIRFI-3 Mk-2 correlator
in N. Novgorod, Russia and NRTV processor in Noto, Italy. The first results of
these experiments are presented.


title: Rapid X-ray Variability of Seyfert 1 Galaxies

abstract:
  The rapid and seemingly random fluctuations in X-ray luminosity of Seyfert
galaxies provided early support for the standard model in which Seyferts are
powered by a supermassive black hole fed from an accretion disc. However, since
EXOSAT there has been little opportunity to advance our understanding of the
most rapid X-ray variability. Observations with XMM-Newton have changed this.
We discuss some recent results obtained from XMM-Newton observations of Seyfert
1 galaxies. Particular attention will be given to the remarkable similarity
found between the timing properties of Seyferts and black hole X-ray binaries,
including the power spectrum and the cross spectrum (time delays and
coherence), and their implications for the physical processes at work in
Seyferts.


title: VLBI-experiments on research of solar wind plasma

abstract:
  This work devotes to investigations of solar corona and solar wind plasma by
the method of radio probing with using of very long baseline interferometry
(VLBI). We performed the theoretical calculation of power spectrum of
interferometric response to radio source emission, passed through the turbulent
medium. Data of theoretical analysis are compared with results of international
VLBI experiments on investigations of solar wind plasma. The observations were
realized in 1998, 1999, 2000 with participation of radio telescopes, included
at Low Frequency VLBI Network (LFVN): Bear Lakes (RT-64, Russia), Puschino
(RT-22, Russia), Urumqi (RT-25, China), Noto (RT-32, Italy), Shanghai (RT-25,
China) and others. Preprocessing was carried out with using of S2 correlator at
Penticton (Canada). Post processing of experimental data was performed at RRI
(Russia) and was aimed to obtain value of solar wind velocity and index of
spatial spectrum of electron density fluctuations.


title: A simple test for periodic signals in red noise

abstract:
  We demonstrate a simple method for testing the significance of peaks in the
periodogram of red noise data. The procedure was designed to test for spurious
periodicities in X-ray light curves of active galaxies, but can be used quite
generally to test for periodic components against a background noise spectrum
assumed to have a power law shape. The method provides a simple and fast test
of the significance of candidate periodic signals in short, well-sampled time
series such as those obtained from XMM-Newton observations of Seyfert galaxies,
without the need for Monte Carlo simulations. A full account is made of the
number of trials and the uncertainties inherent to the model fitting. Ignoring
these subtle effects can lead to substantially overestimated significances.
These difficulties motivate us to demand high standards of detection (minimum
>99.9 per cent confidence) for periodicities in sources that normally show red
noise spectra. The method also provides a simple means to estimate the power
spectral index, which may be an interesting parameter itself, regardless of the
presence/absence of periodicities.


title:
Anisotropic gaseous models of tidally limited star clusters --
  comparison with other methods

abstract:
  We present new models of the evolution and dissolution of star clusters
evolving under the combined influence of internal relaxation and external tidal
fields, using the anisotropic gaseous model based on the Fokker-Planck
approximation, and a new escaper loss cone model. This model borrows ideas from
loss cones of stellar distributions near massive black holes, and describes
physical processes related to escaping stars by a simple model based on two
timescales and a diffusion process. We compare our results with those of direct
$N$-body models and of direct numerical solutions of the orbit-averaged
Fokker-Planck equation. For this comparative study we limit ourselves to
idealized single point mass star clusters, in order to present a detailed study
of the physical processes determining the rate of mass loss, core collapse and
other features of the system's evolution. With the positive results of our
study the path is now open in the future to use the computationally efficient
gaseous models for future studies with more realism (mass spectrum, stellar
evolution).


title: A Search for Stellar Populations in High Velocity Clouds

abstract:
  We report the results of a photometric search for giant stars associated with
the cores of four high velocity clouds (HVCs) -- two of which are compact HVCs
-- using the Las Campanas Du Pont 2.5 meter and Cerro Tololo Blanco 4 meter
telescopes in combination with a system of filters (Washington M, T_2 + DDO51)
useful for identifying low surface gravity, evolved stars. Identical
observations of nearby control fields provide a measure of the ``giant star''
background. Our data reach M_0=22 for three of the HVCs and M_0=21.25 for the
fourth, depths that allow the detection of any giant stars within 600 kpc.
Although we identify a number of faint late-type giant star candidates, we find
neither a coherent red giant branch structure nor a clear excess of giant
candidate counts in any HVC. This indicates that the giant candidates are
probably not related to the HVCs and are more likely to be either random Milky
Way giant stars or one of several classes of potential survey contaminants.
Echelle spectroscopy of the brightest giant candidates in one HVC and its
control field reveal radial velocities representative of the canonical Galactic
stellar populations. In addition to these null results, no evidence of any
young HVC stellar populations -- represented by blue main sequence stars -- is
found, a result consistent with previous searches. Our methodology,
specifically designed to find faint diffuse stellar populations, places the
tightest upper limit yet on the total stellar mass of HVCs of a few 10^5
M_{\sun}.


title: Disk Planet Interactions and Early Evolution in Young Planetary Systems

abstract:
  We study and review disk protoplanet interactions using local shearing box
simulations. These suffer the disadvantage of having potential artefacts
arising from periodic boundary conditions but the advantage, when compared to
global simulations, of being able to capture much of the dynamics close to the
protoplanet at high resolution for low computational cost. Cases with and
without self sustained MHD turbulence are considered. The conditions for gap
formation and the transition from type I migration are investigated and found
to depend on whether the single parameter M_p R^3/(M_* H^3), with M_p, M_*, R
and H being the protoplanet mass, the central mass, the orbital radius and the
disk semi-thickness respectively exceeds a number of order unity. We also
investigate the coorbital torques experienced by a moving protoplanet in an
inviscid disk. This is done by demonstrating the equivalence of the problem for
a moving protoplanet to one where the protoplanet is in a fixed orbit which the
disk material flows through radially as a result of the action of an
appropriate external torque. For sustainable coorbital torques to be realized a
quasi steady state must be realized in which the planet migrates through the
disk without accreting significant mass. In that case although there is
sensitivity to computational parameters, in agreement with earlier work by
Masset & Papaloizou (2003) based on global simulations, the coorbital torques
are proportional to the migration speed and result in a positive feedback on
the migration, enhancing it and potentially leading to a runaway. This could
lead to a fast migration for protoplanets in the Saturn mass range in massive
disks and may be relevant to the mass period correlation for extrasolar planets
which gives a preponderance of sub Jovian masses at short orbital period.


title: Supernova observations fit Einstein-deSitter expansion in 4-sphere

abstract:
  Recent observations on the redshift and magnitude of distant supernovae have
raised fundamental questions of the cosmological structure and the development
of space. Interpretation of the observations with the standard cosmology model
suggests accelerating expansion of space which requires an assumption of
unknown dark energy working against gravitation at cosmological distances. This
paper presents an analysis which shows that the observed magnitude redshift
relationship is in an excellent agreement with the prediction derived by
assuming a zero energy balance of motion and gravitation in an expanding
4-sphere. Such an approach can be regarded as Einstein-deSitter expansion in
the fourth dimension, suggesting a decelerating expansion velocity until zero
in infinity.


title: Dissipative Photosphere Models of Gamma-ray Bursts and X-ray Flashes

abstract:
  We consider dissipative effects occurring in the optically thick inner parts
of the relativistic outflows producing gamma-ray bursts and X-ray flashes,
emphasizing specially the Comptonization of the thermal radiation flux that is
advected from the base of the outflow. Such dissipative effects --e.g. from
magnetic reconnection, neutron decay or shocks -- would boost the energy
density of the thermal radiation. The dissipation can lead to pair production,
in which case the pairs create an effective photosphere further out than the
usual baryonic one. In a slow dissipation scenario, pair creation can be
suppressed, and the effects are most important when dissipation occurs below
the baryonic photosphere. In both cases an increased photospheric luminosity is
obtained. We suggest that the spectral peak in gamma ray bursts is essentially
due to the Comptonized thermal component from the photosphere, where the
comoving optical depth in the outflow falls to unity. Typical peak photon
energies range between those of classical bursts and X-ray flashes. The
relationship between the observed photon peak energy and the luminosity depends
on the details of the dissipation, but under plausible assumptions can resemble
the observed correlations.


title: Adaptive Scheduling Algorithms for Planet Searches

abstract:
  High-precision radial velocity planet searches have surveyed over ~2000
nearby stars and detected over ~200 planets. While these same stars likely
harbor many additional planets, they will become increasingly challenging to
detect, as they tend to have relatively small masses and/or relatively long
orbital periods. Therefore, observers are increasing the precision of their
observations, continuing to monitor stars over decade timescales, and also
preparing to survey thousands more stars. Given the considerable amounts of
telescope time required for such observing programs, it is important use the
available resources as efficiently as possible. Previous studies have found
that a wide range of predetermined scheduling algorithms result in planet
searches with similar sensitivities. We have developed adaptive scheduling
algorithms which have a solid basis in Bayesian inference and information
theory and also are computationally feasible for modern planet searches. We
have performed Monte Carlo simulations of plausible planet searches to test the
power of adaptive scheduling algorithms. Our simulations demonstrate that
planet searches performed with adaptive scheduling algorithms can
simultaneously detect more planets, detect less massive planets, and measure
orbital parameters more accurately than comparable surveys using a non-adaptive
scheduling algorithm. We expect that these techniques will be particularly
valuable for the N2K radial velocity planet search for short-period planets as
well as future astrometric planet searches with the Space Interferometry
Mission which aim to detect terrestrial mass planets.


title: Phantom Thermodynamics Revisited

abstract:
  Although generalized Chaplygin phantom models do not show any big rip
singularities, we investigated k-essence models together with noncanonical
kinetic energy for which there might be a big rip future singularity in the
phantom region. We present our results by finely tuning the parameter ($\beta$)
which is closely related to the canonical kinetic term in $k$-essence
formalism. The scale factor $a(t)$ could be negative and decreasing within a
specific range of $\beta$ during the initial evolutional period. There will be
no singularity for the scale factor for all times once $\beta$ is carefully
selected.


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

abstract:
  In the preprint astro-ph/0411161 (hereafter G04b), the term -(Omega r/c)
sin(theta')cos(Theta) is missing in the equation (13) for cos(psi). So, in this
is supplementary preprint I give the corrected expression for cos(psi) and the
revised derivation of aberration phase shift.


title:
NIR Spectroscopy of Luminous Infrared Galaxies and the Hydrogen
  Recombination Photon Deficit

abstract:
  We report on near-infrared medium-resolution spectroscopy of a sample of
luminous and ultra luminous infrared galaxies (LIRGs-ULIRGs), carried out with
SOFI at the ESO 3.5m New Technology Telescope. Because of wavelength dependence
of the attenuation, the detection of the Pa_alfa or Br_gamma line in the Ks
band should provide relevant constraints on SFR and the contribution of an AGN.
We find, however, that the intensities of the Pa_alfa and Br_gamma lines, even
corrected for slit losses, are on average only 10% and 40%, respectively, of
that expected from a normal starburst of similar bolometric luminosity. The
corresponding star formation rates, after correcting for the attenuation
derived from the NIR-optical emission line ratios, are 14% and 60% of that
expected if the far infrared luminosity were entirely powered by the starburst.
This confirms the existence of a recombination photon deficit, particularly in
the case of the Pa_alfa line, already found in the Br_gamma line in other
infrared galaxies of similar luminosity. In discussing the possible causes of
the discrepancy, we find unlikely that it is due to the presence of an AGN,
though two objects show evidence of broadening of the Pa_alfa line and of the
presence of coronal line emission. In fact, from our own observations and data
collected from the literature we argue that the studied galaxies appear to be
predominantly powered by a nuclear starburst. Two scenarios compatible with the
present data are that either there exists a highly attenuated nuclear star
forming region, and/or that a significant fraction of the ionizing photons are
absorbed by dust within the HII regions. We suggest that observations in the
Br_alpha spectral region could constitute a powerful tool to disentangle these
two possibilities.


title:
Search for radiative pumping lines of OH masers: I. The 34.6um
  absorption line towards 1612 MHz OH maser sources

abstract:
  The 1612 MHz hydroxyl maser in circumstellar envelopes has long been thought
to be pumped by 34.6um photons. Only recently, the Infrared Space Observatory
has made possible spectroscopic observations which enable the direct
confirmation of this pumping mechanism in a few cases. To look for the presence
of this pumping line, we have searched the Infrared Space Observatory Data
Archive and found 178 spectra with data around 34.6um for 87 galactic 1612MHz
masers. The analysis performed showed that the noise level and the spectral
resolution of the spectra are the most important factors affecting the
detection of the 34.6um absorption line. Only 5 objects from the sample (3 red
supergiants and 2 galactic center sources) are found to show clear 34.6um
absorption (all of them already known) while two additional objects only
tentatively show this line. The 3 supergiants show similar pump rates and their
masers might be purely radiatively pumped. The pump rates of OH masers in late
type stars are found to be about 0.05, only 1/5 of the theoretical value of
0.25 derived by Elitzur (1992). We have also found 16 maser sources which,
according to the analysis assuming Elitzur's pump rate, should show the 34.6
$\mu$m absorption line but do not. These non-detections can be tentatively
explained by far-infrared photon pumping, clumpy nature of the OH masing region
or a limb-filling emission effect in the OH shell.


title:
Spectral evolution of and radiation energy generation by coeval stellar
  populations with different initial composition and chemical enrichment

abstract:
  The results, obtained with evolutionary synthesis code package, developed by
the author, for spectral properties of stellar populations with different
initial metallicities Z, are presented and discussed . Also, their
contributions to the production of most common nucleosynthesis elements He, C
and O were followed. These computations have been performed on the basis of two
available but different homogeneous multicomposition stellar evolutionary
tracks grids by Geneva and Padova groups and the Kurucz model atmospheres.
  Next to the discussion of overall effects and evelutionary differences,
caused by chemical composition, we also present and comment the normalized per
stellar mass unit standard tables of the detailed radiation energy output from
stellar populations, integrated over the whole lifetime of their stars, in
function of metallicity, likewise the tables on He, C and O production. They
might serve as useful tools for studies of cosmological problems as well as for
studies of buildup of heavy elements in the Universe and galactic enrichment.
from stellar populations in dependence


title:
The Cosmic Microwave Background Bipolar Power Spectrum: Basic Formalism
  and Applications

abstract:
  We study the statistical isotropy (SI) of temperature fluctuations of the CMB
as distinct from Gaussianity. We present a detailed formalism of the bipolar
power spectrum (BiPS) which was introduced as a fast method of measuring the
statistical isotropy by Hajian & Souradeep 2003. The method exploits the
existence of patterns in the real space correlations of the CMB temperature
field. We discuss the applications of BiPS in constraining the topology of the
universe and other theoretical scenarios of SI violation. Unlike the
traditional methods of search for cosmic topology, this method is
computationally fast. We also show that BiPS is potentially a good tool to
detect the effect of observational artifacts in a CMB map such as non-circular
beam, anisotropic noise, etc. Our method has been successfully applied to the
Wilkinson Microwave Anisotropy Probe sky maps by Hajian et al. 2004, but no
strong evidence of SI violation was found.


title: Physics of Supernovae

abstract:
  Global properties of different types of supernovae are overviewed. A special
emphasis is made on the issues of interest both for the supernova and cosmic
ray physics such as supernova shock waves and neutrino signal.


title: Plasma Frequency Shift Due to a Slowly Rotating Compact Star

abstract:
  We investigate the effects of a slowly rotating compact gravitational source
on electron oscillations in a homogeneous electrically neutral plasma in the
absence of an external electric or magnetic field. Neglecting the random
thermal motion of the electrons we assume the gravitoelectromagnetic
approximation to the general theory of relativity for the gravitational field.
It is shown that there is a shift in the plasma frequency and hence in the
dielectric constant of the plasma due to the gravitomagnetic force. We also
give estimates for the difference in the frequency of radially transmitted
electromagnetic signals for typical compact star candidates.


title:
Regimes of Stability and Scaling Relations for the Removal Time in the
  Asteroid Belt: A Simple Kinetic Model and Numerical Tests

abstract:
  We report on our theoretical and numerical results concerning the transport
mechanisms in the asteroid belt. We first derive a simple kinetic model of
chaotic diffusion and show how it gives rise to some simple correlations (but
not laws) between the removal time (the time for an asteroid to experience a
qualitative change of dynamical behavior and enter a wide chaotic zone) and the
Lyapunov time. The correlations are shown to arise in two different regimes,
characterized by exponential and power-law scalings. We also show how is the
so-called "stable chaos" (exponential regime) related to anomalous diffusion.
Finally, we check our results numerically and discuss their possible
applications in analyzing the motion of particular asteroids.


title: Linear Theory of Thin, Radially-Stratified Disks

abstract:
  We consider the nonaxisymmetric linear theory of radially-stratified disks.
We work in a shearing-sheet-like approximation, where the vertical structure of
the disk is neglected, and develop equations for the evolution of a plane-wave
perturbation comoving with the shear flow (a shearing wave, or ``shwave''). We
calculate a complete solution set for compressive and incompressive
short-wavelength perturbations in both the stratified and unstratified
shearing-sheet models. We develop expressions for the late-time asymptotic
evolution of an individual shwave as well as for the expectation value of the
energy for an ensemble of shwaves that are initially distributed isotropically
in k-space. We find that: (i) incompressive, short-wavelength perturbations in
the unstratified shearing sheet exhibit transient growth and asymptotic decay,
but the energy of an ensemble of such shwaves is constant with time (consistent
with Afshordi, Mukhopadhyay & Narayan 2004); (ii) short-wavelength compressive
shwaves grow asymptotically in the unstratified shearing sheet, as does the
energy of an ensemble of such shwaves; (iii) incompressive shwaves in the
stratified shearing sheet have density and azimuthal velocity perturbations
\delta \Sigma,\delta v_y ~ t^{-Ri} (for |Ri| << 1), where Ri = N_x^2/(q
\Omega)^2 is the Richardson number, N_x^2 is the square of the radial
Brunt-Vaisala frequency and q\Omega is the effective shear rate; (iv) the
energy of an ensemble of incompressive shwaves in the stratified shearing sheet
behaves asymptotically as Ri t^{1-4Ri} for |Ri| << 1. For Keplerian disks with
modest radial gradients, |Ri| is expected to be << 1, and there will therefore
be weak growth in a single shwave for Ri < 0 and near-linear growth in the
energy of an ensemble of shwaves, independent of the sign of Ri.


title: Nonhelical turbulent dynamos: shocks and shear

abstract:
  Small scale turbulent dynamo action in compressible transonic turbulence is
discussed. It is shown that the critical value of the magnetic Reynolds number
displays a bimodal behavior and changes from a typical value of 35 for small
Mach numbers to about 80 for larger Mach numbers. The transition between the
two regimes is relatively sharp. The direct simulations are then compared with
simulations where shocks are captured using a shock viscosity that becomes
large at locations where there are shocks. In the presence of shear it is shown
that large scale dynamo action is possible.


title: The Cluster Soft Excess: new faces of an old enigma

abstract:
  Until the advent of XMM-Newton, the cluster soft excess (CSE) was the subject
of some controversy due to both data analysis issues and uncertainties with the
soft excess emission mechanism. XMM-Newton observations have finally laid to
rest any doubts as to the existence of the CSE and have also given tantalising
clues as to the nature of its emission mechanism. Here we report on the
analysis of XMM-Newton observations of a number of CSE clusters in an attempt
to improve the analysis and understanding of the CSE. Included as part of the
study is an analysis of the effects of background subtraction, which calls to
question the integrity of the claimed O VII line discovery, though not the soft
excess itself. We also give details of both thermal and non-thermal fits to the
CSE cluster Abell 3112.


title:
Warm Molecular Gas Traced with CO J=7->6 in the Galaxy's Central 2
  Parsecs: Dynamical Heating of the Circumnuclear Disk

abstract:
  We present an 11 arcsec resolution map of the central two parsecs of the
Galaxy in the CO J =7->6 rotational transition. The CO emission shows rotation
about Sgr A*, but also evidence for non-circular turbulent motion and a clumpy
morphology. We combine our dataset with available CO measurements to model the
physical conditions in the disk. We find that the molecular gas in the region
is both warm and dense, with T~200-300 K, n_H2~50,000-70,000 cm^-3. The mass of
warm molecular gas we measure in the central two parsecs is at least 2000
M_solar, about 20 times the UV-excited atomic gas mass, ruling out an UV
heating scenario for the molecular material. We compare the available spectral
tracers with theoretical models and conclude that molecular gas is heated with
magneto-hydrodynamic shocks with v~10-20 kms and B~0.3-0.5 mG. Using the
conditions derived with the CO analysis, we include the other important
coolants--neutral oxygen and molecular hydrogen--to estimate the total cooling
budget of the molecular material. We derive a mass to luminosity ratio of 2-3
M_solar/ L_solar, which is consistent with the total power dissipated via
turbulent decay in 0.1 pc cells with v_rms~15 kms. These size and velocity
scales are comparable to the observed clumping scale and the velocity
dispersion. At this rate, the material near Sgr A* its dissipating its orbital
energy on an orbital timescale, and cannot last for more than a few orbits. Our
conclusions support a scenario in which the features near Sgr A* such as the
CND and northern arm are generated by infalling clouds with low specific
angular momentum.


title: Comments on "Sudden future singularities "

abstract:
  We make comments on the letter by Barrow [{\it Class. Quantum Grav.} {\bf 21}
(2004) L79] since we cannot observe a singularity for $p(t)$ as $t\to t_s$.
Instead, there might be a singularity for $\rho(t)$ for $t\sim 0$ case.


title: A search for Interstellar absorptions towards Sgr dSph

abstract:
  We searched for Na I D1,D2 interstellar absorption lines towards 12 giant
stars of the Sgr dwarf spheroidal and 3 stars of the associated globular
cluster Terzan 7, observed at high resolution with the UVES spectrograph at the
8.2 m Kueyen VLT telescope. These stars are not an ideal background source for
the analysis of interstellar (IS) absorption lines since they have been
observed in the framework of a stellar abundances study. However they are
sufficiently luminous to allow a decent S/N ratio at a resolution of about
43000, i.e. ~7 km/s, which allows an exploratory study. We detected two
distinct groups of IS absorptions, a ``local'' group, with radial velocities
ranging from -43 km/s to 50 km/s, and a high velocity group with radial
velocities ranging from 150 km/s to 165 km/s. Likely the high velocity
components are due to gas falling on the Sgr dSph since have been observed only
in 2 stars which are separated by only 1.5' in the sky. We argue that the
observations suggest a stripping of gas due to the passage of Sgr through the
Galactic disc.


title: Discovering the microJy Radio VLBI Sky via "Full-beam" Self-calibration

abstract:
  We demonstrate that at 1.4 GHz the combined response of sources detected
serendipitously in deep, wide-field VLBI images is sufficient to permit
self-calibration techniques to be employed. This technique of "full-beam" VLBI
self-calibration permits coherent VLBI observations to be successfully
conducted in any random direction on the sky, thereby enabling very faint radio
sources to be detected. Via full-beam self-calibration, Global VLBI
observations can equal and indeed surpass the level of sensitivity achieved by
connected arrays. This technique will enable large-scale VLBI surveys of the
faint radio source population to be conducted, in addition to targeted
observations of faint sources of special interest (e.g. GRBs, SNe, SNR and
low-luminosity AGN).


title:
Analysis of a XMM-Newton Spectrum of the Extremely Hot White Dwarf in
  Nova V4743 Sgr

abstract:
  Classical novae occur in close binary systems (main-sequence star + white
dwarf). V4743 Sgr is a very fast nova exhibiting a X-ray spectrum which is
consistent with a view on the optically thick atmosphere of an extremely hot
white dwarf (WD). It exhibits strong absorption features of the C V, C VI, N
VI, N VII, and O VII resonance lines indicating an effective temperature of
about 610 kK.
  We present preliminary results of a spectral analysis by means of
line-blanketed non-LTE atmosphere models of a XMM-Newton RGS-1 spectrum of
V4743 Sgr, taken about half a year after its outburst.


title: Real vs. simulated relativistic jets

abstract:
  Intensive VLBI monitoring programs of jets in AGN are showing the existence
of intricate emission patterns, such as upstream motions or slow moving and
quasi-stationary componentes trailing superluminal features. Relativistic
hydrodynamic and emission simulations of jets are in very good agreement with
these observations, proving as a powerful tool for the understanding of the
physical processes taking place in the jets of AGN, microquasars and GRBs.
These simulations show that the variability of the jet emission is the result
of a complex combination of phase motions, viewing angle selection effects, and
non-linear interactions between perturbations and the underlying jet and/or
ambient medium. Both observations and simulations suggest that shock-in-jet
models may be an overly simplistic idealization when interpreting the emission
structure observed in actual jets.


title: 86 GHz polarimetry of OVV1633+382 after a major mm flare

abstract:
  The 18 mag QSO 1633+382 (4C38.41, z=1.807) showed a very pronounced outburst
in 2001/2002. With a peak amplitude of more than 9 Jy at 90GHz, this flare was
brighter than any known previous flare in this source (data available since
1980).During onset, the mm-flare was particulary fast, with an increase of more
than 2 Jy at 230 GHz in less than 8 days. Since January 2002, the mm-flux of
1633+382 is decaying. During this decline, however, local flux variations with
amplitudes of 1-3 Jy were seen, indicative of underlying and more rapid source
activity on time scales of 1-2 months. After the main peak occurring in
2001.99, the 90 GHz flux showed secondary maxima at approximately half year
intervals in 2002.3, 2002.7 and 2003.13. This kind of periodicity might be
explained via the lighthouse model (Camenzind and Krockenberger 1992), which is
based on the magnetic accelerator of Blanford and Payne (1982). At present the
millimeter flux is nearly back to its quiescent level of 2-2.5 Jy, which the
source had before the flare began. Our VLBA Polarimetry monitoring started June
2002 during the onset of the flare. At cm wavelength, the flare is only
marginally detected which implies very high opacity of the source.


title: Radio-loud and radio-quiet X-ray binaries: LSI+61o303 Galaxies

abstract:
  The three basic ingredients - a spinning compact object, an accretion disc
and a collimated relativistic jet - make microquasars a galactic scaled-down
version of the radio-loud AGN. That explains the large interest attributed to
this new class of objects, which up to now consists of less than 20 members.
Microquasars belong to the much larger class of X-ray binary systems, where
there exits a compact object together with its X-ray emitting accretion disc,
but the relativistic jet is missing. When does an X-ray binary system evolve
into a microquasar? Ideal for studying such kind of a transition is the
periodic microquasar LSI+61deg303 formed by a compact object accreting from the
equatorial wind of a Be star and with more than one event of super-critical
accretion and ejection along the eccentric orbit. For ejections at periastron
passage the relativistic electrons suffer severe inverse Compton losses by
upscattering the UV photons of the Be star at high energy : At periastron
passage Gamma-ray emission has been observed, whereas radio outbursts have
never been observed in 20 years of radio flux monitoring. For ejections
displaced from periastron passage the losses are less severe and radio
outbursts are observed. The radio emission mapped on scales from a few AU to
hundreds of AU shows a double-sided relativistic (beta=0.6c) S-shaped jet,
similar to the well-known precessing jet of SS433.


title: VLBI observations of young Type II supernovae

abstract:
  We give an overview of circumstellar interaction in young Type II supernovae,
as seen through the eyes of very-long-baseline interferometry (VLBI)
observations. The resolution attained by such observations (best than 1 mas) is
a powerful tool to probe the interaction that takes place after a supernova
goes off. The direct imaging of a supernova permits, in principle, to estimate
the deceleration of its expansion, and to obtain information on the eject and
circumstellar density profiles, as well as estimates of the magnetic field
intensity and relativistic particle energy density in the supernova.
Unfortunately, only a handful of radio supernovae are close and bright enough
as to permit their study with VLBI. We present results from our high-resolution
observations of the nearby Type II radio supernovae SN1986J and SN2001gd.


title:
Continuum EVN and MERLIN observations of Ultra Luminous Infrared
  Galaxies

abstract:
  Radio imaging of ULIR galaxies is ideal to explore the connection between the
starburst and the AGN phenomenon since it is unaffected by dust obscuration,
and provides the required high angular resolution to distinguish between an AGN
and starburst emission. We have made combined 18cm radio continuum, EVN and
MERLIN observations of 13 ULIRGs that have the parsec and deci-parsec scale
resolution necessary to distinguish between an AGN and supernovae remnants at
the centres of these galaxies, and assess the contribution of each to the total
energy distribution. Images of four galaxies are presented here.


title: Packet Loss in High Data Rate Internet Data Transfer for eVLBI

abstract:
  VLBI is gradually moving to the point where Gbps data rates are becoming
routine. A number of experiments have shown that the internet can be used at
data rates of several hundred Mbps on production networks. However use of the
network is accompanied by packet loss. The paper discusses the statistics of
packet loss as found by recent tests and investigates the expected effect of
packet loss on correlator performance and signal to noise ratio on eVLBI
observations. The relative merits of UDP versus TCP are also discussed.


title: Cryogenic Filters for RFI Mitigation in Radioastronomy

abstract:
  RFI mitigation in Radioastronomy can be achieved adopting cryogenic filters
in appropriate typologies. A study has been conducted in L, C and X band with
the evaluation of the filter architecture in copper, with theoretical
estimation, computer simulations, prototypes realization, laboratory
measurements. Such work has been preliminary to the realization of HTS samples
with the purpose of a similar complete characterization approach.


title: On the Near-term Space VLBI Mission VSOP-2

abstract:
  A second generation near-term space VLBI mission, VSOP-2, is being planned
for a launch in 2010 or soon after. The scientific objectives are very high
angular resolution imaging of astrophysically exotic regions, including the
cores, jets, and accretion disks of active galactic nuclei (AGN), water maser
emissions, micro-quasars, coronae of young stellar objects, etc. A highest
angular resolution of about 40 microarcseconds is achieved in the 43 GHz band.
Engineering developments are in progress for the deployable antenna, antenna
pointing, high data rate transmission, cryogenic receivers, accurate orbit
determination, etc., to realize this mission. International collaboration will
be as important as it has been for VSOP.


title:
Long-range interactions between dark-matter particles in a model with a
  cosmological, spontaneously-broken chiral symmetry

abstract:
  In a cosmological model with a chiral symmetry, there are two,
dynamically-related spin-zero fields, a scalar $\phi$ and a pseudoscalar $b$.
These fields have self-interactions. Spontaneous symmetry breaking results in a
very massive scalar particle with $m_\phi\cong 5 \times 10^{11}\GeV$, and a
nearly massless, (Goldstone-like) pseudoscalar particle with $0< m_b <~
2.7\times 10^{-6}\eV$. One or both particles can be part of dark matter. There
are coherent long-range interactions (at range $\sim 1/m_b \simgt 10\cm$), from
exchange of a $b$ particle between a pair of $b$ particles, a pair of $\phi$
particles, and between a $\phi$ and a $b$. We compare the strength of
potentials for the different pairs to the corresponding gravitational
potentials (within the same range $\sim 1/m_b$), and show that the new force
dominates between a b pair, that gravitation dominates between a $\phi$ pair,
and that the potentials are comparable for a $\phi$-$b$ pair. The new
interaction strength between a $b$ pair is comparable to the gravitational
interaction between a $\phi$ pair; its possibly greater coherent effect
originates in the possibility that the number density of a very light $b$ can
be greater than that of a massive $\phi$. We consider these results in the
context of recent speculations concerning possible effects of special forces
between dark-matter particles on certain galactic, and inter-galactic,
properties.


title:
Star Formation in Isolated Disk Galaxies. I. Models and Characteristics
  of Nonlinear Gravitational Collapse

abstract:
  We model gravitational collapse leading to star formation in a wide range of
isolated disk galaxies using a three-dimensional, smoothed particle
hydrodynamics code. The model galaxies include a dark matter halo and a disk of
stars and isothermal gas. Absorbing sink particles are used to directly measure
the mass of gravitationally collapsing gas. They reach masses characteristic of
stellar clusters. In this paper, we describe our galaxy models and numerical
methods, followed by an investigation of the gravitational instability in these
galaxies. Gravitational collapse forms star clusters with correlated positions
and ages, as observed, for example, in the Large Magellanic Cloud.
Gravitational instability alone acting in unperturbed galaxies appears
sufficient to produce flocculent spiral arms, though not more organized
patterns. Unstable galaxies show collapse in thin layers in the galactic plane;
associated dust will form thin dust lanes in those galaxies, in agreement with
observations. (abridged)


title: Evidence for unusual events in high energy cosmic ray interactions

abstract:
  Anomalous events with a large transverse momenta $P_T$ were found for all
secondary particles in an analysis of experimental data on cosmic ray
interactions at $E_0 > 5\cdot 10^{13} eV$. In order to clarify the underlying
mechanism of these events, the intermittency analysis of interactions with both
large and usual transverse momentum was performed. It is shown that behavior of
intermittency indices $\phi (q)$ as a function of rank factorial momentum $q$
for such interactions is very peculiar. The indices show slight growth for the
events with large transverse momenta for all secondary particles in contrast
with the fast growth for events with normal average transverse momenta for
final particles. The significant difference in the behavior of intermittency
indices gives strong evidence on the existence of the new class of hadron
interactions with large $P_T$ for all secondary particles in the event. A
possible interpretation of these anomalous events as a manifistation of Color
Glass Condensate in high energy hadron-hadron interactions is given.


title:
The far-infrared emission line and continuum spectrum of the Seyfert
  galaxy NGC 1068

abstract:
  The first complete far-infrared spectrum (43-197um) of the Seyfert 2 galaxy
NGC 1068 as observed with the LWS onboard ISO is reported. In addition to the
expected ionic fine structure emission lines, the OH rotational lines at 79,
119 and 163um were all detected in emission. The line intensities were modelled
together with ISO SWS and optical and UV line intensities from the literature,
considering two independent emission components: the AGN component and the
starburst component in the circumnuclear ring of 3 kpc in size. Using the UV to
mid-IR emission line spectrum to constrain the nuclear ionizing continuum, we
have confirmed previous results: a canonical power-law ionizing spectrum is a
poorer fit than one with a deep absorption trough, while the presence of a big
blue bump is ruled out. Based on starburst synthesis models, we were able to
fit the mid- and far-infrared fine-structure line emission, with a low
ionization parameter (logU=-3.5) and low densities (n=100 cm^-3). Combining AGN
and starburst components, we succeeded in modeling the overall UV to far-IR
atomic spectrum of NGC1068, reproducing the line fluxes to within a factor 2.0
on average with a standard deviation of 1.3 and the overall continuum as the
sum of the contribution of the thermal dust emission in the ionized and neutral
components. TheOH 119 um emission indicates that the line is collisionally
excited and arises in a warm and dense region. The OH emission has been modeled
using spherically symmetric, non-local, non-LTE radiative transfer models. The
models indicate that the bulk of the emission arises from the nuclear region,
although some extended contribution from the starburst is not ruled out. The OH
abundance in the nuclear region is expected to be $\sim10^{-5}$, characteristic
of X-ray dominated regions.


title: Discovering M-Dwarf Companions with STEPS

abstract:
  The Stellar Planet Survey (STEPS) is an ongoing astrometric search for giant
planets and brown dwarfs around a sample of ~30 M-dwarfs. We have discovered
several low-mass companions by measuring the motion of our target stars
relative to their reference frames. We describe the STEPS method for stellar
centroiding that enables our ~1 milliarcsecond relative astrometry. We describe
one of the astrometrically discovered companions, GJ 1210B, which was later
confirmed with an imaging observation. GJ 1210 A and B have spectral types
M4-5, based on their luminosities, inferred masses, and colors.


title:
Constraints on the Cardassian Expansion from the Cosmic Lens All-Sky
  Survey Gravitational Lens Statistics

abstract:
  The existence of a dark energy component has usually been invoked as the most
plausible way to explain the recent observational results. However, it is also
well known that effects arising from new physics (e.g., extra dimensions) can
mimic the gravitational effects of a dark energy through a modification of the
Friedmann equation. In this paper we investigate some observational
consequences of a flat, matter dominated and accelerating/decelerating scenario
in which this modification is given by $H^{2} = g(\rho_m, n, q)$ where
$g(\rho_m, n, q)$ is a new function of the energy density $\rho_m$, the
so-called generalized Cardassian models. We mainly focus our attention on the
constraints from the recent Cosmic All Sky Survey (CLASS) lensing sample on the
parameters $n$ and $q$ that fully characterize the models. We show that, for a
large interval of the $q - n$ parametric space, these models are in agreement
with the current gravitational lenses data. The influence of these parameters
on the acceleration redshift, i.e., the redshift at which the universe begins
to accelerate, and on the age of the universe at high-redshift is also
discussed.


title: Local Starbursts: Perspectives from the Optical

abstract:
  The optical regime is historically the best-studied wavelenght range. Gas
ionized by massive stars produces optical emission lines that have been used to
derive indicators of star-formation rate, metallicity, dust reddening, and the
ionization conditions of the interstellar medium. Absorptions lines have been
used to measure velocity dispersions, and the 4000 A break has been shown to be
a useful indicator of the mean age of stellar populations. I briefly summarize
some recent work done on, specifically, star formation rate indicators, in view
of their importance for understanding star-forming galaxies at high redshift.


title: Hidden bipolarity in red supergiant winds

abstract:
  Many observations of late-type M stars show large near-spherical
circumstellar envelopes, yet planetary nebulae and supernova remnants are
frequently axisymmetric. We present VLBI and MERLIN observations of masers
around the red supergiant S Per which show varying degrees of axisymmetry and a
dynamically significant magnetic field. There is no evidence for rotation here
or in most similar objects. We examine possible origins of the magnetic field.


title:
Redshift-Space Distortions with the Halo Occupation Distribution I:
  Numerical Simulations

abstract:
  We show how redshift-space distortions of the galaxy correlation function or
power spectrum can constrain the matter density parameter Omega_m and the
linear matter fluctuation amplitude sigma_8. We improve on previous treatments
by adopting a fully non-linear description of galaxy clustering and bias, which
allows us to break parameter degeneracies by combining large-scale and small-
scale distortions. We consider different combinations of Omega_m and sigma_8
and find parameters of the galaxy halo occupation distribution (HOD) that yield
nearly identical galaxy correlation functions in real space. We use these HOD
parameters to populate the dark matter halos of large N-body simulations, from
which we measure redshift-space distortions on small and large scales. We
include a velocity bias parameter alpha_v that allows the velocity dispersions
of satellite galaxies in halos to be systematically higher or lower than those
of dark matter. Large-scale distortions are determined by the parameter
combination beta = Omega_m^{0.6}/b_g, where b_g is the galaxy bias, in
agreement with linear theory. However, linear theory does not accurately
describe the distortions themselves on scales accessible to our simulations. We
provide fitting formulas to estimate beta from the redshift-space correlation
function or power spectrum, and we show that these formulas are significantly
more accurate than those in the existing literature. On small scales, the
``finger-of-god'' distortions at projected separations ~0.1 Mpc/h depend on
Omega_m*alpha_v^2 but are independent of sigma_8, while at intermediate
separations they depend on sigma_8 as well. One can thus use redshift-space
distortions over a wide range of scales to separately determine Omega_m,
sigma_8, and alpha_v. (Abridged)


title:
A Possible High Nova Rate for Two Local Group Dwarf Galaxies: M32 and
  NGC 205

abstract:
  We report the results of a preliminary nova survey of Local Group dwarf
ellipticals. We used the Tenagra Observatory to observe M32, NGC 205, NGC 147,
and NGC 185 in their entirety every clear night over a 4.5 month interval and
discovered one nova in M32 and a candidate nova in NGC 205. The nova in M32 was
verified spectroscopically. The nova candidate in NGC 205 had an unusually low
peak luminosity (M_V = -5.1), and we were unable to obtain spectroscopic
verification. We report a high bulk nova rate for M32 of 2(+2.4,-1.0) yr^-1
and, assuming the candidate nova is correctly identified, for NGC 205 of
2(+2.2,-1.0) yr^-1. If the NGC 205 variable is not a nova, we calculate an
upper limit on the bulk nova rate for NGC 205 of 1.5 yr^-1. We report upper
limits on the bulk nova rates in NGC 147 of 2 yr^-1 and NGC 185 of 1.8 yr^-1
and a combined bulk nova rate for the four galaxies of 4(+4.2,-1.4) yr^-1
(2{+3.9,-1.4} yr^-1 without the NGC 205 nova candidate). From the bulk rates,
integrated and extinction corrected V-band photometry, and (V-K)_0 colors we
derive a luminosity specific nova rate for M32 of 12.0(+14.4,-6.0) yr^-1 [10^10
L_Sun,K]^-1 and for NGC 205 of 29.3(+32.3,-14.7) yr^-1 [10^10 L_Sun,K]^-1 and
for the combined 4 galaxies of 14.1(+14.8,-4.9) yr^-1 [10^10 L_Sun,K]^-1
(7.0{+13.7,-4.9} yr^-1[10^10 L_Sun,K]^-1 without the NGC 205 nova candidate).
If the higher rate is confirmed by surveys in subsequent seasons, it would
imply that either dwarf ellipticals have a higher interacting binary fraction
than their higher mass counter parts, or that the completeness is higher for
these less complex systems and the nova rates for larger, more distant systems
are systematically underestimated.


title:
A Chandra Study of the Multi-Component X-ray Emission from the X-shaped
  Radio Galaxy 3C 403

abstract:
  We present results from a 49.4 ks Chandra/ACIS-S observation of the nearby
($z$=0.059) X-shaped FRII radio galaxy 3C~403. This is the first Chandra
observation of an X-shaped radio galaxy, and one of the goals of this
pioneering study is to determine the relationship between the X-ray emitting
gas and the X-shaped radio morphology. The X-ray isophotes of the hot gas
within $\sim3.5''$ of the central galaxy are highly elliptical
(eccentricity$\sim$0.57) and co-aligned with the elliptical optical isophotes.
This supports the hypothesis that X-shaped radio sources are created by
propagation of jets through asymmetric density distributions. Within large
uncertainties, there is no evidence that the lobes or wings are overpressurized
relative to the ISM. We have detected X-ray emission from several of the radio
knots to the E of the active nucleus, and diffuse emission from the radio lobe
to the W. The X-ray emission from the eastern knots cannot be explained by an
inverse Compton model unless they are far from equipartition. Using archival
HST data, optical emission is detected from two knots, and the
radio/optical/X-ray spectra are well fitted by simple synchrotron models. This
is one of the strongest examples to date of X-ray synchrotron emission from
multiple knots in the jet of an FR II radio galaxy. X-ray emission is also
detected from the radio wings at a flux consistent with inverse Compton
scattering of CMB photons from relativistic electrons if the wings are near
equipartition. The nuclear spectrum is well described by a multi-component
model that includes a heavily absorbed power law and a bright, broadened Fe
line. A second, less absorbed, power-law component, likely to represent
unresolved emission from a pc-scale jet, is also required.


title:
Evidence for Correlated Titanium and Deuterium Depletion in the Galactic
  ISM

abstract:
  Current measurements indicate that the deuterium abundance in diffuse
interstellar gas varies spatially by a factor of ~4 among sightlines extending
beyond the Local Bubble. One plausible explanation for the scatter is the
variable depletion of D onto dust grains. To test this scenario, we have
obtained high signal-to-noise, high resolution profiles of the refractory ion
TiII along seven Galactic sightlines with D/H ranging from 0.65 to 2.1x10^-5.
These measurements, acquired with the recently upgraded Keck/HIRES
spectrometer, indicate a correlation between Ti/H and D/H at the >95% c.l.
Therefore, our observations support the interpretation that D/H scatter is
associated with differential depletion. We note, however, that Ti/H values
taken from the literature do not uniformly show the correlation. Finally, we
identify significant component-to-component variations in the depletion levels
among individual sightlines and discuss complications arising from this
behavior.


title: Rates of Horizontal Tau Air-Showers observable by satellites

abstract:
  Up-going and Horizontal Tau Air-Showers, UpTaus and HorTaus, may trace Ultra
High Energy Neutrino Tau Earth Skimming at the edge of the horizon. We show
that such events even for minimal GZK neutrino fluxes could be detected by
space telescopes such as the EUSO project. These Horizontal Tau Showers will
track very long fan-like, multi-finger showers whose signature would be
revealed by EUSO, OWL experiments. Moreover the additional imprint of their
young secondaries muon, electron pairs and gamma bundles flashes might allow to
disentangle their nature from the older UHECR secondaries in horizontal
showers. Indeed at large zenith angles, the muon, electron pairs and gamma
number for far and old Ultra High Energy Cosmic Rays, becomes comparable. On
the contrary up-ward muon bundles from UpTaus and HorTaus (as well as by
anti-neutrino electron + electron resonance at Glashow peak) may arise within a
young shower with a gamma-muon ratio as large as 10^2. Such a very
characteristic imprint maybe observed by Crown detector arrays on Mountain,
planes or balloons in space, as well as by gamma satellites in Space. We
estimate the UpTaus and HorTaus rate from the Earth and the consequent event
rate of +/-mu bundles, whose flux at 92^o -97^o may exceed the up-going muon
flux induced by the atmospheric neutrino, by one or two order of magnitude.


title:
Self-Consistent Dynamic Models of Steady Ionization Fronts I. Weak-D and
  Weak-R Fronts

abstract:
  We present a method for including steady-state gas flows in the plasma
physics code Cloudy, which was previously restricted to modeling static
configurations. The numerical algorithms are described in detail, together with
an example application to plane-parallel ionization-bounded HII regions. As
well as providing the foundation for future applications to more complex flows,
we find the following specific results regarding the effect of advection upon
ionization fronts in HII regions:
  1. Significant direct effects of advection on the global emission properties
occur only when the ionization parameter is lower than is typical for HII
regions.
  2. The overheating of partially ionized gas in the front is not large, even
for supersonic (R-type) fronts.
  3. The most significant morphological signature of advective fronts is an
electron density spike that occurs at the ionization front. Observational
evidence for such a spike is found in images of the Orion bar.
  4. Plane-parallel, weak-D fronts are found to show at best a shallow
correlation between mean velocity and ionization potential for optical emission
lines even when the flow velocity closely approaches the ionized sound speed.


title: A 32 m Parabolic Antenna in Peru At 3,370m of Altitude

abstract:
  At the altitude of 3,370 m on the Peruvian Andes, a 32m antenna owned by the
telecommunications company Telefonica del Peru will be transformed to a Radio
Telescope, it would be transferred to the Geophysical Institute of Peru (IGP).
The parabolic antenna was constructed in 1984 by Nippon Electric Co. (NEC) and
worked as an INTELSAT station until 2000. A team of the National Observatory of
Japan (NAOJ) evaluated the antenna in 2003 and reported its availability to be
used as a Radio Telescope. In collaboration of the NAOJ a 6.7 GHz receiver is
under construction and will be installed within this year. Initially the
telescope as a single dish will monitor and survey Methanol Maser of YSO,
higher frequencies equipment and VLBI instruments will be considered. The
antenna will be managed by the IGP and used by universities in Peru, becoming a
VLBI station will be a grate contribution to astronomy and geodetic community.


title: Strong effects of time-dependent ionization in early SN 1987A

abstract:
  We study a time-dependent hydrogen ionization in the atmosphere of SN 1987A
during the first month after the explosion. The model includes kinetics of
hydrogen ionization and excitation, molecular hydrogen kinetics, and a
time-dependent energy balance. The primary strong effect of the time-dependent
ionization is the enhanced hydrogen ionization compared to the steady-state
model. The time-dependent ionization provides a sufficient population of
excited hydrogen levels to account for the observed H-alpha without invoking
the external Ni-56. We find that the Ba II 6142 A line in SN 1987A can be
reproduced for the LMC barium abundance. This resolves the long-standing
problem of the unacceptably high barium overabundance in SN 1987A. The key
missing factor that should be blamed for the "barium problem" is the
time-dependent ionization. The modelling of the H-alpha profile on day 4.64
indicates the ratio of the kinetic energy to the ejected mass about 0.83
10^{50} erg/Msun.


title:
An H alpha survey of cluster galaxies V: cluster - field comparison for
  early-type galaxies

abstract:
  We have extended our H alpha objective prism survey of 8 low-redshift
clusters (viz. Abell 262, 347, 400, 426, 569, 779, 1367 and 1656) to include a
complete sample of early-type galaxies within 1.5 Abell radii of the cluster
centres. Of the 379 galaxies surveyed, 3% of E, E-S0 galaxies, 6% of S0s and 9%
of S0/a galaxies were detected in emission. From a comparison of cluster and
supercluster field galaxies, we conclude that the frequency of emission-line
galaxies (ELGs; W_lambda >/= 20 angstroms) is similar for field and cluster
early-type galaxies. A similar result has previously been obtained for galaxies
of types Sa and later. Together, these results confirm the inference of Biviano
et al. that the relative frequency of ELGs in clusters and the field can be
entirely accounted for by the different mix of morphological types between the
differing environments. Detected emission is classified as `compact' or
`diffuse', identified as circumnuclear starburst or AGN emission and disk
emission respectively. By comparing spectroscopic data for cluster early-type
ELGs with data for field galaxies from the Palomar Spectroscopic Survey of
nearby galactic nuclei, we demonstrate there is modest evidence for an
enhancement of compact HII emission relative to AGN emission in the early-type
cluster ELGs as compared to the field. For the cluster early-type galaxies,
compact HII emission correlates strongly with a disturbed morphology. This
suggests that, as for later type cluster galaxies, this enhanced compact HII
emission can readily be explained as an enhancement of circumnuclear starburst
emission due to gravitational tidal interactions, most likely caused by
sub-cluster merging and other on-going processes of cluster virialisation.


title:
The Insignificance of P-R Drag in Detectable Extrasolar Planetesimal
  Belts

abstract:
  This paper considers a simple model in which dust produced in a planetesimal
belt migrates in toward the star due to P-R drag suffering destructive
collisions with other dust grains on the way. Assuming the dust is all of the
same size, the resulting surface density distribution can be derived
analytically and depends only on the parameter eta0=5000tau*sqrt(Mstar/r)/beta;
this parameter can be determined observationally with the hypothesis that
beta=0.5. For massive belts in which eta0>>1 dust is confined to the
planetesimal belt, while the surface density of more tenuous belts, in which
eta0<<1, is constant with distance from the star. The emission spectrum of dust
from planetesimal belts at different distances from different mass stars shows
that the dust belts which have been detected to date should have eta0>>1; dust
belts with eta0<<1 are hard to detect as they are much fainter than the stellar
photosphere. This is confirmed for a sample of 37 debris disk candidates for
which eta0 was determined to be >10. This means that these disks are so massive
that mutual collisions prevent dust from reaching the inner regions of these
systems and P-R drag can be ignored when studying their dynamics. Models for
the formation of structure in debris disks by the trapping of particles into
planetary resonances by P-R drag should be reconsidered. However, since
collisions do not halt 100% of the dust, this means that in the absence of
planetary companions debris disk systems should be populated by small
quantities of hot dust which may be detectable in the mid-IR. Even in disks
with eta0<<1 the temperature of dust emission is shown to be a reliable tracer
of the planetesimal distribution meaning that inner holes in the dust
distribution imply a lack of colliding planetesimals in the inner regions.


title: New Gamma-Ray Probe of the Baryonic Dark Matter

abstract:
  We expand on the recently reported detections of the gamma-ray resonant
absorption along the line of sight toward gamma-ray bright quasars (QSOs), like
3C279. We propose to use this novel gamma-ray absorption method to study the
Dark Matter distribution in the Milky Way, as well as in the Local Group.
Properties of the absorber that was detected on the sight lines towards
gamma-ray bright QSOs at zero redshift are discussed. We compare our results
with the expected Dark Matter distributions in the halo of Milky Way, that were
simulated in boundaries of different CDM models. Application of this new method
to study evolution of CDM in the QSO host galaxies, and of baryons distribution
in the halo of galaxies in the Local Universe is proposed.


title: Discovery of magnetic fields in central stars of planetary nebulae

abstract:
  For the first time we have directly detected magnetic fields in central stars
of planetary nebulae by means of spectro-polarimetry with FORS1 at the VLT. In
all four objects of our sample we found kilogauss magnetic fields, in NGC1360
and LSS1362 with very high significance, while in EGB5 and Abell36 the
existence of a magnetic field is probable but with less certainty. This
discovery supports the hypothesis that the non-spherical symmetry of most
planetary nebulae is caused by magnetic fields in AGB stars. Our high discovery
rate demands mechanisms to prevent full conservation of magnetic flux during
the transition to white dwarfs.


title: A unified description of anti-dynamo conditions for incompressible flows

abstract:
  A general type of mathematical argument is described, which applies to all
the cases in which dynamo maintenance of a steady magnetic field by motion in a
uniform density is known to be impossible. Previous work has demonstrated that
magnetic field decay is unavoidable under conditions of axisymmetry and in
spherical or planar incompressible flows. These known results are encompassed
by a calculation for flows described in terms of a generalized
poloidal-toroidal representation of the magnetic field with respect to an
arbitrary two dimensional surface. We show that when the velocity field is two
dimensional, the dynamo growth, if any, that results, is linear in one of the
projections of the field while the other projections remain constant. We also
obtain criteria for the existence of and classification into two and three
dimensional velocity results which are satisfied by a restricted set of
geometries. In addition, we discuss the forms of spatial variation of the
density and the resistivity that are allowed so that field decay still occurs
for this set of geometries.


title:
Active Galactic Nuclei in the Sloan Digital Sky Survey: II.
  Emission-Line Luminosity Function

abstract:
  The emission line luminosity function of active galactic nuclei (AGN) is
measured from about 3000 AGN included in the main galaxy sample of the Sloan
Digital Sky Survey within a redshift range of $0<z<0.15$. The $\Ha$ and
[OIII]$\lambda 5007$ luminosity functions for Seyferts cover luminosity range
of $10^{5-9}$$L_\odot$ in H$\alpha$ and the shapes are well fit by broken power
laws, without a turnover at fainter nuclear luminosities. Assuming a universal
conversion from emission line strength to continuum luminosity, the inferred B
band magnitude luminosity function is comparable both to the AGN luminosity
function of previous studies and to the low redshift quasar luminosity function
derived from the 2dF redshift survey. The inferred AGN number density is
approximately 1/5 of all galaxies and about $6\times 10^{-3}$ of the total
light of galaxies in the $r$-band comes from the nuclear activity. The numbers
of Seyfert 1s and Seyfert 2s are comparable at low luminosity, while at high
luminosity, Seyfert 1s outnumber Seyfert 2s by a factor of 2-4. In making the
luminosity function measurements, we assumed that the nuclear luminosity is
independent of the host galaxy luminosity, an assumption we test {\it a
posteriori}, and show to be consistent with the data. Given the relationship
between black hole mass and host galaxy bulge luminosity, the lack of
correlation between nuclear and host luminosity suggests that the main variable
that determines the AGN luminosity is the Eddington ratio, not the black hole
mass. This appears to be different from luminous quasars, which are most likely
to be shining near the Eddington limit.


title:
Large scale correlations of quasar polarisation vectors: Hints of
  extreme scale structures?

abstract:
  A survey measuring quasar polarization vectors has been started in two
regions towards the North and South Galactic Poles. Here, We review the
discovery of significant correlations of orientations of polarization vectors
over huge angular distances. We report new results including a larger sample of
the quasars confirming the existence of coherent orientations at redshifts z>1.


title:
Calculating the submillimeter emissivity of dust grains in spiral
  galaxies

abstract:
  We use the radiation transfer simulation of Xilouris et al. (1999) to
constrain the quantity of dust in three nearby spiral galaxies (NGC 4013, NGC
5907 and NGC 891). The predicted visual optical depth from the model is
compared with the thermal continuum radiation detected from these galaxies at
850 microns. This comparison yields the emissivity of dust grains in the
submillimeter waveband which is a factor 4 higher than the benchmark,
semi-empirical model of Draine & Lee (1984). Our estimates are more closely
aligned with recent measurements carried out in the laboratory on amorphous
carbon and silicate particulates. A comparison between the distribution of 850
microns surface brightness and the intensity levels in the ^{12}CO(1-0) and 21
cm lines underlines the spatial association between dust detected in the
submillimeter waveband and molecular gas clouds. We suggest that the relatively
high emissivity values that we derive may be attributable to amorphous, fluffy
grains situated in denser gas environments.


title: Radiation Transfer Models in Galaxies

abstract:
  The dust in galaxies makes radiation transport calculations in them
absolutely necessary. It is not only common practice in Astrophysics, but also
wisdom, to try to make as simple models as possible to simulate physical
systems. For spiral galaxies, however, this turned out to be catastrophic. For
years, the major question of the opacity of spiral galaxies kept the community
divided, because the models were too simple. A spiral galaxy appears, to first
order, to have exponential distributions of stars and dust, which cannot be
approximated with uniform distributions. We will review the radiative transfer
methods used in galaxies and we will comment on their pluses and minuses. We
will also present some of the main results of the application of one of the
methods to the observations.


title: IceTop Status in 2004

abstract:
  IceTop is the surface component of IceCube neutrino telescope. Goals, plans
and status of IceTop in 2004 are reported


title: Dust in a merging galaxy sequence: the SCUBA view

abstract:
  We investigate the cold and warm dust properties during galaxy interactions
using a merging galaxy sample ordered into a chronological sequence from pre-
to post-mergers. Our sample comprises a total of 29 merging systems selected to
have far-infrared and sub-millimeter observations. We use the 100-to-850 micron
flux density ratio, f100/f850, as a proxy to the mass fraction of the warm and
the cold dust in these systems. We find evidence for an increase in f100/f850
along the merging sequence from early to advanced mergers and interpret this
trend as an increase of the warm relative to the cold dust mass. We argue that
the two key parameters affecting the f100/f850 flux ratio is the star-formation
rate and the dust content of individual systems relative to the stars. Using a
sophisticated model for the absorption and re-emission of the stellar UV
radiation by dust we show that these parameters can indeed explain both the
increase and the observed scatter in the f100/f850 along the merging galaxy
sequence.


title:
Modelling the dust content of spiral galaxies: More dust mass vs.
  enhanced dust grain emissivity

abstract:
  We present detailed modelling of the spectral energy distribution (SED) of
the spiral galaxies NGC 891, NGC 4013, and NGC 5907 in the far-infrared (FIR)
and sub-millimeter (submm) wavelengths. The model takes into account the
emission of the diffuse dust component, which is heated by the UV and optical
radiation fields produced by the stars, as well as the emission produced
locally in star forming HII complexes. The radiative transfer simulations of
Xilouris et al. (1999) in the optical bands are used to constrain the stellar
and dust geometrical parameters, as well as the total amount of dust. We find
that the submm emission predicted by our model can not account for the observed
fluxes at these wavelengths. We examine two cases, one having more dust
embedded in a second thin disk and another allowing for an enhanced
submillimeter emissivity of the dust grains. We argue that both cases can
equally well reproduce the observed SED. The case of having more dust embedded
in a second disk though, is not supported by the near-infrared observations and
thus more realistic distributions of the dust (i.e., in spiral arms and clumps)
have to be examined in order to better fit the surface brightness of each
galaxy.


title: How do brown dwarves form?

abstract:
  We review and evaluate four mechanisms for forming brown dwarves: (i)
dynamical ejection of a stellar embryo from its placental prestellar core; (ii)
opacity-limited fragmentation of a shock-compressed layer; (iii) gravitational
instabilities in discs, triggered by impulsive interactions with other discs or
naked stars; and (iv) photo-erosion of pre-existing cores. All these mechanisms
can produce free-floating brown dwarves, but only (ii) and (iii) are likely to
produce brown dwarves in multiple systems, and (i) has difficulty delivering
brown dwarves with discs.


title: Wakes in Dark Matter Halos

abstract:
  I discuss the dynamical interaction of galactic disks with the surrounding
dark matter halos. In particular it is demonstrated that if the
self-gravitating shearing sheet, a model of a patch of a galactic disk, is
embedded in a live dark halo, this has a strong effect on the dynamics of
density waves in the sheet. I describe how the density waves and the halo
interact via halo particles either on orbits in resonance with the wave or on
non-resonant orbits. Contrary to expectation the presence of the halo leads to
a very considerable enhancement of the amplitudes of the density waves in the
shearing sheet. This effect appears to be the equivalent of the recently
reported enhanced growth of bars in numerically simulated stellar disks
embedded in live dark halos. Finally I discuss the counterparts of the
perturbations of the disk in the dark halo.


title: G337.2+0.1: a new X-ray supernova remnant?

abstract:
  We present evidence supporting a SNR origin for the radio source G337.2+0.1,
which was discovered along the line of sight to the Norma spiral arm in the
MOST 843-MHz radio survey. The radio source is spatially superposed to the
unidentified ASCA source AX J1635.9-4719. An analysis of this latter source
reveals that its X-ray spectrum, extended nature, and non-variable flux are
consistent with what is expected for a SNR. In addition, we have used HI-line
observations of the region to look for any effect of the presumed remnant on
the ISM. We have found a well-defined minimum centered at the position of the
radio source in the velocity range of ~ -25 to -19 km/s. This feature appears
as a sharp absorption dip in the spectrum that might be produced when the
continuum emission from the SNR candidate is absorbed by foreground gas. Hence
we have used it to constrain the distance to the source, which seems to be a
young (age ~ a few 10^3 yr) and distant (d ~ 14 kpc) SNR. G337.2+0.1 and AX
J1635.9-4719 would be the radio/X-ray manifestations of this remnant.