title:
A low global star formation rate in the rich galaxy cluster AC114 at
  z=0.32

abstract:
  We present the results of a wide-field survey for H-alpha emitting galaxies
in the cluster AC114 at z=0.32. Spectra centred on H-alpha at the cluster
redshift have been obtained for 586 galaxies to I~22 out to a radius around
2Mpc. At most, only ~10% of these were found to be H-alpha-emitting cluster
members. These objects are predominantly blue and of late-type spiral
morphology, consistent with them hosting star formation. However, ~65% of the
cluster members classified morphologically as spirals (with HST), have no
detectable H-alpha emission; star-formation and morphological evolution in
cluster galaxies appear to be largely decoupled. Changes in the H-alpha
detection rate and the strength of H-alpha emission with environment are found
to be weak within the region studied. Star formation within the cluster members
is also found to be strongly and uniformly suppressed, with the rates inferred
from the H-alpha emission not exceeding 4Mo/yr, and AC114's H-alpha luminosity
function being an order of magnitude below that observed for field galaxies at
the same redshift. None of the galaxies detected have the high star formation
rates associated with `starburst' galaxies; however, this may still be
reconciliable with the known (8+/-3%) fraction of `post-starburst' galaxies
within AC114, given the poorly determined but short lifetimes of starbursts and
the possibility that much of the associated star formation is obscured by dust.


title: Observations of Ammonia in External Galaxies. II. Maffei 2

abstract:
  The ammonia (J,K) = (1,1), (2,2), (3,3), and (4,4) transitions at 23.7 --
24.1 GHz region were searched for in a nearby galaxy Maffei 2 to study relation
between molecular abundances and physical conditions in galaxies. The (1,1),
(2,2), and (3,3) emission lines were clearly detected. The rotational
temperatures and ortho-to-para abundance ratios obtained are about 30 K and
about 2.6, respectively. The abundance of NH3 relative to H2 in Maffei 2 was
found to be the largest among galaxies where NH3 is already detected, and the
abundance in Maffei 2 is more than an order of magnitude larger than the
already reported upper limit in M82. Hence, we further confirmed the
systematically peculiar molecular abundance in the aspect of formation
mechanisms of molecules already reported in M82.


title: Ram-Pressure Stripping on Dwarf Galaxies

abstract:
  We use SPH/N-body simulations to study the ram-pressure stripping of the gas
of dwarf galaxies orbiting in a disc galaxy. The effects of the gaseous disc
and halo on the satellites are analysed and the results are compared with the
observations of the dwarf spheroidals (and dwarf irregulars) in the Local
Group. The stripped gas is compared with the High Velocity Clouds. Finally, a
model of evolution of the dwarfs is proposed.


title:
Deprojection Galaxy Cluster X-ray, Sunyaev-Zel'dovich Temperature
  Decrement and Weak Lensing Mass Maps

abstract:
  A general method of deprojecting two-dimensional images to reconstruct the
three dimensional structure of the projected object --specifically X-ray,
Sunyaev-Zel'dovich (SZ) and gravitational lensing maps of rich clusters of
galaxies -- assuming axial symmetry (Zaroubi et. al. 98), is considered. Here
we test the applicability of the method for realistic, numerically simulated
galaxy clusters, viewed from three orthogonal projections at four redshift
outputs. We demonstrate that the assumption of axial symmetry is a good
approximation for the 3D structure in this ensemble of galaxy clusters.
Applying the method, we demonstrate that a unique determination of the cluster
inclination angle is possible from comparison between the SZ and X-ray images
and, independently, between SZ and surface density maps. Moreover, the results
from these comparisons are found to be consistent with each other and with the
full 3D structure inclination angle determination. The radial dark matter and
gas density profiles as calculated from the actual and reconstructed 3D
distributions show a very good agreement. The method is also shown to provide a
direct determination of the baryon fraction in clusters, independent of the
cluster inclination angle.


title: On the soft X-ray spectrum of cooling flows

abstract:
  Strong evidence for cooling flows has been found in low resolution X-ray
imaging and spectra of many clusters of galaxies. However high resolution X-ray
spectra of several clusters from the Reflection Grating Spectrometer (RGS) on
XMM-Newton now show a soft X-ray spectrum inconsistent with a simple cooling
flow. The main problem is a lack of the emission lines expected from gas
cooling below 1--2 keV. Lines from gas at about 2--3 keV are observed, even in
a high temperature cluster such as A 1835, indicating that gas is cooling down
to about 2--3 keV, but is not found at lower temperatures. Here we discuss
several solutions to the problem; heating, mixing, differential absorption and
inhomogeneous metallicity. Continuous or sporadic heating creates further
problems, including the targetting of the heat at the cooler gas and also the
high total energy required. So far there is no clear observational evidence for
widespread heating, or shocks, in cluster cores, except in radio lobes which
occupy only part of the volume. The implied ages of cooling flows are short, at
about 1 Gyr. Mixing. or absorption, of the cooling gas are other possibilities.
Alternatively, if the metals in the intracluster medium are not uniformly
spread but are clumped, then little line emission is expected from the gas
cooling below 1 keV. The low metallicity part cools without line emission
whereas the strengths of the soft X-ray lines from the metal-rich gas depend on
the mass fraction of that gas and not on the abundance, since soft X-ray line
emission dominates the cooling function below 2 keV.


title: RXJ 0852.0-0462: Another Nonthermal Shell-Type SNR (G266.2-1.2)

abstract:
  The newly discovered supernova remnant G266.2-1.2 (RX J0852.0--0462), along
the line of sight to the Vela SNR, was observed with ASCA for 120 ks. We find
that the X-ray spectrum is featureless, and well described by a power law,
extending to three the class of shell-type SNRs dominated by nonthermal X-ray
emission. Like G347.3-0.5, this low-latitude remnant displays discrete regions
of enhanced emission along the rim as well as faint nonthermal emission from
the interior. We derive limits on the thermal content of the remnant emission,
although the presence of the Vela SNR compromises our ability to seriously
constrain a low temperature component. Limits placed on the amount of Sc-K
emission are compared with the expected flux based upon the reported 44Ti
emission from G2662.-1.2. We also report on an unresolved X-ray source
surrounded by diffuse emission near the center of the remnant. The properties
of the source are not well determined, but appear consistent with the
interpretation that the source is a neutron star surrounded by a synchrotron
nebula. Alternatively, the source may be associated with one of two stars
located within the positional error circle, but this appears somewhat unlikely.


title: Lifting cosmic degeneracy within a single quasar survey

abstract:
  In the almost Friedmann-Lema^itre model of the Universe, the density
parameter, Omega_matter, and the cosmological constant, Omega_Lambda, measure
curvature. Several linearly degenerate relations between these two parameters
have recently been measured. Here, large scale structure correlations at
\~100-150 h^-1 Mpc are found in the comoving three-dimensional separations of
redshift z \approx 2 quasars. These function as a comoving standard rod of
length L_LSS \approx 130+-10 h^-1 Mpc. A local maximum in the correlation
function at \approx L_LSS/2 also appears to be significant. By combining
separate radial and tangential standard ruler analyses, the lifting of the
Omega_matter - Omega_Lambda linear degeneracy within a single data set is
demonstrated for the first time.


title: Shape and geometry of galaxy clusters and the SZ effect

abstract:
  We discuss the influence of the finite extension and the geometry of clusters
of galaxies, as well as of the polytropic temperature profile, on the
determination of the Hubble constant.


title: The very lithium rich post-AGB SB2 binary HD172481

abstract:
  Double lined spectroscopic binaries in an evolved stage of evolution are
expected to be extremely rare since they must consist of equally luminous and
thus almost equally evolved objects, which requires an extremely similar
initial mass. In this contribution we discuss such rare double evolved SB2
system: HD172481. This binary includes an F-type post-AGB object and an M-type
AGB companion. The spectrum shows a surprisingly strong LiI 670.8nm line with
an equivalent width of 54mA yielding a lithium abundance of log(Li)=3.6.
Several explanations for this huge lithium content are explored.


title: Solar variability and climate

abstract:
  Recent precise observations of solar global parameters are used to calibrate
an upgraded solar model which takes into account magnetic fields in the solar
interior. Historical data about sunspot numbers (from 1500 to the present) and
solar radius changes (between 1715 and 1979) are used to compute solar
variability on years to centuries timescales. The results show that although
the 11 year variability of the total irradiance is of the order of 0.1%,
additional, longer lived changes of the order of 0.1% may have occurred in the
past centuries. These could, for example, account for the occurrence of climate
excursions such as little ice ages.


title: The Star Clusters in the Irregular Galaxy NGC 4449

abstract:
  We examine the star clusters in the irregular galaxy NGC 4449. We use a
near-infrared spectrum and broad-band images taken with the HST to place a
limit of 8--15 Myrs on the age of the bright central ojbect in NGC 4449. Its
luminosity and size suggest that it is comparable to young super star clusters.
However, there is a peculiar nucleated-bar structure at the center of this star
cluster, and we suggest that this structure is debris from the interaction that
has produced the counter-rotating gas systems and extended gas streamers in the
galaxy.
  From the images we identify 60 other candidate compact star clusters in NGC
4449. Fourteen of these could be background elliptical galaxies or old globular
star clusters. Of the star clusters, three, in addition to the central object,
are potentially super star clusters, and many others are comparable to the
populous clusters found in the LMC. The star clusters span a large range in
ages with no obvious peak in cluster formation that might be attributed to the
interaction that the galaxy has experienced.


title: The FIRST-APM QSO survey (FAQS) in the SBS Region. Preliminary Results

abstract:
  The main goal of the FIRST-APM QSO Survey (FAQS) survey is to compile the
most complete sample of Bright QSOs, located in the area covered by the Second
Byurakan Survey (SBS). Here we report the first results of an ongoing study
based on the cross-identification of the FIRST radio catalog and the APM
optical catalog. The overlapping sky area between FIRST and SBS is about 700
deg$^{2}$. The compiled list of sources for this overlapping region contains
$\sim 400$ quasar candidates brighter than $B=18\fm5$. About 90 objects were
already spectroscopically classified. During 1999-2000, we observed
spectroscopically more than 150 FAQS objects with the 2.1m telescope of the
Guillermo Haro Observatory (GHO).We have found 51 new QSOs (4 BAL QSOs), 13
Seyfert Galaxies (5 NLSy1's), 23 emission line galaxies, 3 BL Lac objects and
57 stars.


title: Viscous Transonic Decretion in Disks of Be Stars

abstract:
  We study the characteristics of the outflow in disks of Be stars, based on
the viscous decretion disk scenario. In this scenario, the matter ejected from
the equatorial surface of the star drifts outward because of the effect of
viscosity, and forms the disk. For simplicity, we adopt the alpha-prescription
for the viscous stress, and assume the disk to be isothermal. Solving the
resulting wind equations, we find that a transonic solution exists for any
value of alpha. The sonic point is located at r>100R for plausible values of
parameters, where R is the stellar radius. The sonic radius is smaller for
higher temperature and/or larger radiative force. We also find that the
topology of the sonic point is nodal for alpha>0.95, while it is of saddle type
for alpha<0.9. We expect that the sonic point in the former case is unstable,
whereas that in the latter case is stable. The outflow is highly subsonic in
the inner part of the disk. Roughly, the outflow velocity increases linearly
with r and the surface density decreases as r^{-2}. Interestingly, the disk is
near Keplerian in the inner subsonic region, while it is angular momentum
conserving in the outer subsonic region and in the supersonic region. Our
results, together with the observed range of the base density for Be star
disks, suggest that the mass loss rate in the equatorial region is at most
comparable with that in the polar region.


title: Radio polarization from the inner Galaxy at arcminute resolution

abstract:
  The Southern Galactic Plane Survey (SGPS) is an HI and 1.4-GHz continuum
survey of the 4th quadrant of the Galaxy at arcmin resolution. We present here
results on linearly polarized continuum emission from an initial
28-square-degree Test Region for the SGPS, consisting of 190 mosaiced pointings
of the Australia Telescope Compact Array, and covering the range 325.5 < l <
332.5, -0.5 < b < +3.5. Complicated extended structure is seen in linear
polarization throughout the Test Region, almost all of which has no correlation
with total intensity. We interpret the brightest regions of polarized emission
as representing intrinsic structure in extended polarization, most likely
originating in the Crux spiral arm at a distance of 3.5 kpc; fainter polarized
structure is imposed by Faraday rotation in foreground material. Two large
areas in the field are devoid of polarization. We argue that these voids are
produced by foreground HII regions in which the magnetic field is disordered on
scales of ~0.1-0.2 pc. We also identify a depolarized halo around the HII
region RCW 94, which we suggest results from the interaction of the HII region
with a surrounding molecular cloud.


title: Dense Gas in Nearby Galaxies: XIV. Detection of hot ammonia in Maffei 2

abstract:
  The (J,K) = (1,1), (2,2), (3,3), and (4,4) inversion lines of ammonia (NH3)
have been detected toward the nuclear 40'' sized bar of the nearby spiral
galaxy Maffei 2. The relative intensities of the ammonia lines are
characterized by a rotational temperature of 85 K. This is higher than
rotational temperatures measured toward IC342 and most Galactic Center clouds,
implying kinetic temperatures of at least 100 K. Since the kinetic temperature
of the gas is larger than that of the dust, NH3 is tracing a particularly dense
warm gas component that is heated by young massive stars, cloud-cloud
collisions, or ion-slip heating in the nuclear starburst. The gas north of the
nucleus (V(LSR} = -80 km/s) is more highly excited than the gas further south
(+6 km/s). This asymmetry might be related to a pronounced morphological
distortion that is observed in the north-eastern part of the galaxy.


title: Spiral structure parameters in the solar neighbourhood

abstract:
  Two samples of O- and B-type stars and Cepheids with Hipparcos data have been
used to characterize galactic rotation and spiral arm kinematics in the solar
neighbourhood. An extensive set of simulations has been performed in order to
assess the capabilities of the method and its sensitivity to sample errors and
biases in the adopted parameters.


title: Non-linearity and Non-Gaussianity through Phase Information

abstract:
  In the standard picture of structure formation, initially random-phase
fluctuations are amplified by non-linear gravitational instability to produce a
final distribution of mass which is highly non-Gaussian and has highly coupled
Fourier phases. Second-order statistics, such as the power spectrum, are blind
to this kind of phase association. We discuss the information contained in the
phases of cosmological density fluctuations and their possible use in
statistical analysis tools. In particular, we show how the bispectrum measures
a particular form of phase association called quadratic phase coupling, show
how to visualise phase association using colour models. These techniques offer
the prospect of more complete tests of initial non-Gaussianity than those
available at present.


title: Nuclear star formation in the hot-spot galaxy NGC2903

abstract:
  We present high-resolution near-infrared imaging obtained using adaptive
optics and HST/NICMOS, and ground-based spectroscopy of the hot-spot galaxy
NGC2903. Our near-infrared resolution imaging enables us to resolve the
infrared hot spots into individual young stellar clusters or groups of these.
The spatial distribution of the stellar clusters is not coincident with that of
the bright HII regions, as revealed by the HST/NICMOS Pa_alpha image. Overall,
the circumnuclear star formation in NGC2903 shows a ring-like morphology with
an approximate diameter of 625pc.
  The SF properties of the stellar clusters and HII regions have been studied
using the photometric and spectroscopic information in conjunction with
evolutionary synthesis models. The population of bright stellar clusters shows
a very narrow range of ages, 4-7 X 10^6 yr after the peak of star formation, or
absolute ages 6.5-9.5 X 10^6yr (for the assumed short-duration Gaussian
bursts), and luminosities similar to the clusters found in the Antennae
interacting galaxy. This population of young stellar clusters accounts for some
7-12% of the total stellar mass in the central 625pc of NGC2903. The HII
regions in the ring of star formation have luminosities close to that of the
super-giant HII region 30 Doradus, they are younger than the stellar clusters,
and will probably evolve into bright infrared stellar clusters similar to those
observed today. We find that the star formation efficiency in the central
regions of NGC2903 is higher than in normal galaxies, approaching the lower end
of infrared luminous galaxies.


title:
Accretion column eclipses in the X-ray pulsars GX 1+4 and RX
  J0812.4-3114

abstract:
  Sharp dips observed in the pulse profiles of three X-ray pulsars (GX 1+4, RX
J0812.4-3114 and A 0535+26) have previously been suggested to arise from
partial eclipses of the emission region by the accretion column occurring once
each rotation period. We present pulse-phase spectroscopy from Rossi X-ray
Timing Explorer satellite observations of GX 1+4 and RX J0812.4-3114 which for
the first time confirms this interpretation. The dip phase corresponds to the
closest approach of the column axis to the line of sight, and the additional
optical depth for photons escaping from the column in this direction gives rise
to both the decrease in flux and increase in the fitted optical depth measured
at this phase. Analysis of the arrival time of individual dips in GX~1+4
provides the first measurement of azimuthal wandering of a neutron star
accretion column. The column longitude varies stochastically with standard
deviation 2-6 degrees depending on the source luminosity. Measurements of the
phase width of the dip both from mean pulse profiles and individual eclipses
demonstrates that the dip width is proportional to the flux. The variation is
consistent with that expected if the azimuthal extent of the accretion column
depends only upon the Keplerian velocity at the inner disc radius, which varies
as a consequence of the accretion rate Mdot.


title:
The unique rapid variabilities of the iron K$\alpha$ line profiles in
  NGC 4151

abstract:
  We present a detailed analysis of the iron K$\alpha$ line variabilities in
NGC 4151 by using long ASCA observation data obtained in May 1995. Despite the
relatively small amplitude variations in the continuum flux, the iron K$\alpha$
line flux and profile show dramatic variations. Particularly, the line profile
changes from single peak to seeming double peaks and back in time scales of a
few 10$^4$ sec. The seemingly double-peaked profiles can be well interpreted as
line emission from a Keplerian ring around a massive black hole. An absorption
line at around 5.9 keV is also marginnaly detected. We discussed current Fe K
line models, but none of them can well explain the observed line and continuum
variations.


title: Formation and structure of halos in a warm dark matter cosmology

abstract:
  (Abridged) Using high-resolution cosmological N-body simulations, we study
how the density profiles of dark matter halos are affected by the filtering of
the density power spectrum below a given scale length and by the introduction
of a thermal velocity dispersion. In the warm dark matter (WDM) scenario, both
the free-streaming scale, R_f, and the velocity dispersion, v_w, are determined
by the mass m_w of the WDM particle. We find that v_w is too small to affect
the density profiles of WDM halos. Down to the resolution attained in our
simulations, there is not any significant difference in the density profiles
and concentrations of halos obtained in simulations with and without the
inclusion of v_w. The density profiles of halos with masses down to ~0.01 the
filtering mass M_f can be described by the NFW shape; significant soft cores
are not formed. Nevertheless, the concentrations of these halos are lower than
those of the CDM counterparts and are approximately independent of mass. The
lower concentrations of WDM halos with respect to their CDM counterparts can be
accounted for their late formation epoch. Overall, our results point to a
series of advantages of a WDM model over the CDM one. In addition to solving
the substructure problem, a WDM model with R_f~0.16 Mpc (m_w~0.75 kev; flat
cosmology with Omega_L=h=0.7) also predicts concentrations, a Tully-Fisher
relation, and formation epochs for small halos which seems to be in better
agreement with observations, relative to CDM predictions.


title:
Fundamental Properties and Distances of LMC Eclipsing Binaries II. HV
  982

abstract:
  We have determined the distance to a second eclipsing binary system (EB) in
the Large Magellanic Cloud, HV982 (~B1 IV-V + ~B1 IV-V). The measurement of the
distance -- among other properties of the system -- is based on optical
photometry and spectroscopy and space-based UV/optical spectrophotometry. The
analysis combines the ``classical'' EB study of light and radial velocity
curves, which yields the stellar masses and radii, with a new analysis of the
observed energy distribution, which yields the effective temperature,
metallicity, and reddening of the system plus the distance ``attenuation
factor'', essentially (radius/distance)^2. Combining the results gives the
distance to HV982, which is 50.2 +/- 1.2 kpc. This distance determination
consists of a detailed study of well-understood objects (B stars) in a
well-understood evolutionary phase (core H burning), and is free of the biases
and uncertainties that plague various other techniques. After correcting for
the location of HV982, we find an implied distance to the optical center of the
LMC's bar of d(LMC) = 50.7 +/- 1.2 kpc. This result differs by nearly 5 kpc
from our earlier result for the EB HV2274, which implies a bar distance of 45.9
kpc. These results may reflect either marginally compatible measures of a
unique LMC distance or, alternatively, suggest a significant depth to the
stellar distribution in the LMC. Some evidence for this latter hypothesis is
discussed.


title: A New Spin on Galactic Dust

abstract:
  We present a new puzzle involving Galactic microwave emission and attempt to
resolve it. On one hand, a cross-correlation analysis of the WHAM H-alpha map
with the Tenerife 10 and 15 GHz maps shows that the well-known DIRBE correlated
microwave emission cannot be dominated by free-free emission. On the other
hand, recent high resolution observations in the 8-10 GHz range with the Green
Bank 140 ft telescope by Finkbeiner et al. failed to find the corresponding 8
sigma signal that would be expected in the simplest spinning dust models. So
what physical mechanism is causing this ubiquitous dust-correlated emission? We
argue for a model predicting that spinning dust is the culprit after all, but
that the corresponding small grains are well correlated with the larger grains
seen at 100 micron only on large angular scales. In support of this grain
segregation model, we find the best spinning dust template to involve higher
frequency maps in the range 12-60 micron, where emission from transiently
heated small grains is important. Upcoming CMB experiments such as ground-based
interferometers, MAP and Planck LFI with high resolution at low frequencies
should allow a definitive test of this model.


title: Activity and Kinematics of M and L Dwarfs

abstract:
  I discuss observations of two traditional age indicators, chromospheric
activity and kinematics, in late-M and L dwarfs near the hydrogen-burning
limit. The frequency and strength of chromospheric activity disappears rapidly
as a function of temperature over spectral types M8-L4. There is evidence that
young late-M and L dwarfs have weaker activity than older ones, the opposite of
the traditional stellar age-activity relation. The kinematics of L dwarfs
confirm that lithium L dwarfs are younger than non-lithium dwarfs.


title: SPIRAL Phase A: A Prototype Integral Field Spectrograph for the AAT

abstract:
  We present details of a prototype fiber feed for use on the Anglo-Australian
Telescope (AAT) that uses a dedicated fiber-fed medium/high resolution (R >
10000) visible-band spectrograph to give integral field spectroscopy (IFS) of
an extended object. A focal reducer couples light from the telescope to the
close-packed lenslet array and fiber feed, allowing the spectrograph be used on
other telescopes with the change of a single lens. By considering the
properties of the fibers in the design of the spectrograph, an efficient design
can be realised, and we present the first scientific results of a prototype
spectrograph using a fiber feed with 37 spatial elements, namely the detection
of Lithium confirming a brown dwarf candidate and IFS of the supernova remnant
SN1987A.


title: Color Correlations in (S+S) Binary Galaxies I. The Holmberg Effect

abstract:
  Relying on his photometry of galaxies, Holmberg (1958) found, more than 40
years ago, that the color indices of paired galaxies were closely correlated.
Our deep broad-band BVRI CCD photometry of 45 (S+S) pairs from the Karachentsev
(1972) catalogue (see Hernandez Toledo and Puerari, this volume), and
additional (B-V) color information from the literature (50 extra (S+S) pairs),
help us to confirm the effect. This "Holmberg Effect" has long been remained
unverified and not explained yet.


title: BVRI Surface Photometry of (S+S) Binary Galaxies

abstract:
  We report the first results of our multicolour broad-band BVRI photometry for
a statistically well defined sample of interacting pairs, drawn from the
Catalogue of Isolated Pairs of Galaxies in the Northern Hemisphere Karachentsev
(1972). At present, the details of photometric structure of disk-disk (S+S)
galaxies are just beginning to be studied because of their intrinsic
difficulties. We take advantage of the statistical properties of this well
defined sample of interacting galaxies to try to isolate the main structural
components of galaxies. Due to their environmental simplicity (compared to
groups and clusters), the sample provides an unique opportunity to peform a
photometric study of galaxies and their structural components in a
non-equilibrium configuration. In this contribution, the first results of a
deep multicolour (BVRI) photometric study of a sample of 45 (S+S) isolated
pairs of galaxies is presented. Our attention is focused on the morphology and
the global photometric properties (integrated magnitudes, colours and mean
surface brightness profiles).


title:
The detection of spiral arm modulation in the mass distribution of an
  optically flocculent galaxy

abstract:
  Spiral arm modulation in NGC 4062 (an optical flocculent) is detected for the
first time; the Fourier spectra of NGC 4062 and NGC 5248 (a classic grand
design in optical images) are almost identical.


title:
PopRatio: A program to calculate atomic level populations in
  astrophysical plasmas

abstract:
  We describe a Fortran 90 program to calculate population ratios of atomic
levels. The program solves the equations of statistical equilibrium considering
all possible bound-bound processes: spontaneous, collisional or radiation
induced (the later either directly or by fluorescence). There is no limit on
the number of levels or in the number of processes that may be taken into
account. The program may find a wide range of applicability in astronomical
problems, such as interpreting fine-structure absorption lines or collisionally
excited emission lines (such as coronal emission lines) in the spectra of
several objects, and also in calculating the cooling rates due to collisional
excitation.


title:
The Optical and Near-Infrared Morphologies of Isolated Early Type
  Galaxies

abstract:
  In order to study early type galaxies in their simplest environments, we have
constructed a well-defined sample of 30 isolated galaxies. The sample contains
all RC3 early-type galaxies with no other cataloged galaxy with known redshift
lying within a projected radius of 1 (h_100)^{-1} Mpc and =/- 1000 km/s (where
we use the recessional velocities in the RC3). We have obtained optical and
near-infrared images of 23 of the galaxies and of a comparison sample of 13
early-type galaxies in X-ray detected poor groups of galaxies. We have applied
the techniques of unsharp masking, galaxy model division, and color maps to
search for morphological features that might provide clues to the evolution of
these galaxies. Evidence for dust features is found in approximately 75% of
both the isolated and group galaxies (17 of 22 and 9 of 12, respectively).
However, shells or tidal features are much more prevalent in our isolated
sample than in our group sample (9 of 22 or 41% versus 1 of 12 or 8%,
respectively). The isolation and colors of these shell galaxies make it
unlikely that tidal interactions or asymmetric star formation are the causes of
such features. One model that is not ruled out is that mergers produce the
shells. If shells and dust are both merger signatures, the absence of shells in
group ellipticals implies that shells: 1) form more easily, 2) are younger,
and/or 3) are longer-lived in isolated environments.


title:
Radio Continuum and Recombination Line Study of UC HII Regions with
  Extended Envelopes

abstract:
  We have carried out 21 cm radio continuum observations of 16 UC HII regions
using the VLA (D-array) in search of associated extended emission. We have also
observed H76$_\alpha$ recombination line towards all the sources and
He76$_\alpha$ line at the positions with strong H76$_\alpha$ line emission. The
UC HII regions have simple morphologies and large (>10) ratios of single-dish
to VLA fluxes. Extended emission was detected towards all the sources. The
extended emission consists of one to several compact components and a diffuse
extended envelope. All the UC HII regions but two are located in the compact
components, where the UC HII regions always correspond to their peaks. The
compact components with UC HII regions are usually smaller and denser than
those without UC HII regions. Our recombination line observations indicate that
the ultracompact, compact, and extended components are physically associated.
The UC HII regions and their associated compact components are likely to be
ionized by the same sources on the basis of the morphological relations
mentioned above. This suggests that almost all of the observed UC HII regions
are not `real' UC HII regions and that their actual ages are much greater than
their dynamical age (<10000 yr). We find that most of simple UC HII regions
previously known have large ratios of single-dish to VLA fluxes, similar to our
sources. Therefore, the `age problem' of UC HII regions does not seem to be as
serious as earlier studies argued. We present a simple model that explains
extended emission around UC HII regions. Some individual sources are discussed.


title:
Searching for SUSY Dark Matter- The Directional Rate and the Modulation
  Effect

abstract:
  The detection of dark matter is central to particle physics and cosmology.
Current fashionable supersymmetric models provide a dark matter candidate, the
lightest supersymmetric particle (LSP). When combined with fairly well
understood physics (quark structure of the nucleon and some nuclear structure,
they yield direct event rates. The obtained rates are, however, very low. So we
exploit characteristic signatures, like the modulation effect, i.e. the
dependence of the rate on the earth's annual motion, and the directional rate,
i.e its dependence on the direction of the recoiling nucleus, employing various
velocity distributions, isothermal (symmetric and axially asymmetric) and non
isothermal (due to to caustic rings).


title: Magnetic fields in our Galaxy: How much do we know?

abstract:
  The large scale magnetic fields of our Galaxy have been mostly revealed by
rotation measures ($RM$s) of pulsars and extragalactic radio sources. In the
disk of our Galaxy, the average field strength over a few kpc scale is about
1.8 $\mu$G, while the total field, including the random fields on smaller
scales, has a strength of about 5 $\mu$G. The local regular field, if it is
part of the large scale field of a bisymmetric form, has a pitch angle of about
$-8\degr$. There are at least three, and perhaps five, field reversals from the
Norma arm to the outer skirt of our Galaxy.


title: The shape of pulsar radio beams

abstract:
  Using all available multi-component radio pulse profiles for pulsars with
medium to long periods and good polarisation data, we have constructed a
two-dimensional image of the mean radio beamshape. This shows a peak near the
centre of the beam but is otherwise relatively uniform with only mild
enhancements in a few regions. This result supports the patchy-beam model for
emission beams in which the mean beam shape represents the properties of the
emission mechanism and observed pulse components result from emission sources
distributed randomly across the beam.


title: Structure and Mass Distribution of the Milky Way Bulge and Disk

abstract:
  This article summarizes the structural parameters of the Galactic bulge and
disk, and discusses the interpretation of the bulge microlensing observations
and the determination of the Milky Way's luminous mass from the terminal
velocity curve and the Oort limit. The bulge is a rotating bar with corotation
radius around 4 kpc. The NIR disk has a short scale-length. The measured
surface density of the local disk is in good agreement with the prediction of a
maximum NIR disk model for the Milky Way. The preliminary new value for the
microlensing optical depth of clump giant sources is within $1.7\sigma$ of the
prediction by the maximum NIR disk model, while the optical depth for all
sources is still significantly higher. These results imply that cold dark
matter cannot dominate inside the solar radius.


title:
Properties of post-AGB stars with IRAS colors typical of planetary
  nebulae

abstract:
  We have investigated the infrared properties of a sample of objects with IRAS
colors typical of planetary nebulae. The selected objects have not yet evolved
to the planetary nebula stage since they have no detectable radio continuum
emission and they are therefore likely post-AGB stars.


title:
The effect of violent star formation on the state of the molecular gas
  in M82

abstract:
  We present the results of a high angular resolution, multi-transition
analysis of the molecular gas in M82. The analysis is based on the two lowest
transitions of 12CO and the ground transition of the rare isotopes 13CO and
C18O measured with the PdBI, the BIMA array and the IRAM 30m telescope. In
order to address the question of how the intrinsic molecular cloud properties
are influenced by massive star formation we have carried out radiative transfer
calculations based on the observed CO line ratios. The calculations suggest
that the kinetic temperature of the molecular gas is high in regions with
strong star formation and drops towards the outer molecular lobes with less
ongoing star formation. The location of the highest kinetic temperature is
coincident with that of the mid infrared peaks which trace emission from hot
dust. The hot gas is associated with low H2 densities while the cold gas in the
outer molecular lobes has high H2 densities. We find that CO intensities do not
trace H2 column densities well. Most of the molecular gas is distributed in a
double-lobed distribution which surrounds the starburst. A detailed analysis of
the conversion factor from CO intensity to H2 column density shows that X_CO
depends on the excitation conditions. We find X_CO ~ Sqrt(n_H2)/T_kin, as
expected for virialized clouds.


title: A Young Stellar Cluster in the Nucleus of NGC 4449

abstract:
  We have obtained 1-2 A resolution optical Echellette spectra of the nuclear
star cluster in the nearby starburst galaxy NGC 4449. The light is clearly
dominated by a very young (6-10 Myr) population of stars. For our age dating,
we have used recent population synthesis models to interpret the observed
equivalent width of stellar absorption features such as the HI Balmer series
and the CaII triplet around 8500 A. We also compare the observed spectrum of
the nuclear cluster to synthesized spectra of simple stellar populations of
varying ages. All these approaches yield a consistent cluster age. Metallicity
estimates based on the relative intensities of various ionization lines yield
no evidence for significant enrichment in the center of this low mass galaxy:
the metallicity of the nuclear cluster is about one fourth of the solar value,
in agreement with independent estimates for the disk material of NGC 4449.


title: Shear turbulence beneath the solar tachocline

abstract:
  Helioseismic inversions of the Sun's internal angular velocity profile show
that the rotation changes from differential in latitude in the convection zone
to almost uniform in the radiative region below. The transition occurs in a
thin layer, the tachocline, which is the seat of strong shear in the vertical
direction. In this Note we examine whether this rotation profile can lead to
shear turbulence at the top of the radiation zone. By using the standard solar
model, we show that such turbulence can be generated only in a narrow region
0.695R_sun < r < 0.713R_sun at the equator and even in narrower layers at
higher latitudes. We conclude that the turbulence generated by this vertical
shear is unlikely to play a significant role in the transport of matter and
angular momentum, and that other mechanisms must be invoked to achieve this.


title:
A modest proposal to solve the "missing mass" problem and related
  cosmological paradoxes

abstract:
  Properly interpreted data from nearby galaxies $(z\simeq 0.01)$ lead to
$\Omega \simeq 0.082$. Data from farther away galaxies $(z\simeq 1)$ with type
Ia supernovae to $\Omega =0.153$. Data to be expected from very high redshifted
galaxies $(z\simeq 10.1)$ to $\Omega =0.500$. And actual data from the CBR,
emitted at the time at which the universe became transparent $(z\simeq 1422)$
to $\Omega \simeq 0.992$. All these data are simultaneously consistent with the
standard big-bang picture (no inflation), in which $ \Omega $ is time dependent
and it is given by $\Omega (y)=1/\cosh ^{2}(y)$, being $y\equiv \sinh
^{-1}(T_{+}/T)^{1/2}$


title:
Completely dark galaxies: their existence, properties, and strategies
  for finding them

abstract:
  There are a number of theoretical and observational hints that large numbers
of low-mass galaxies composed entirely of dark matter exist in the field. The
theoretical considerations follow from the prediction of cold dark matter
theory that there exist many low-mass galaxies for every massive one. The
observational considerations follow from the observed paucity of these low-mass
galaxies in the field but not in dense clusters of galaxies; this suggests that
the lack of small galaxies in the field is due to the inhibition of star
formation in the galaxies as opposed to the fact that their small dark matter
halos do not exist. In this work we outline the likely properties of low-mass
dark galaxies, and describe observational strategies for finding them, and
where in the sky to search. The results are presented as a function of the
global properties of dark matter, in particular the presence or absence of a
substantial baryonic dark matter component. If the dark matter is purely cold
and has a Navarro, Frenk and White density profile, directly detecting dark
galaxies will only be feasible with present technology if the galaxy has a
maximum velocity dispersion in excess of 70 km/s, in which case the dark
galaxies could strongly lens background objects. This is much higher than the
maximum velocity dispersions in most dwarf galaxies. If the dark matter in
galaxy halos has a baryonic component close to the cosmic ratio, the
possibility of directly detecting dark galaxies is much more realistic; the
optimal method of detection will depend on the nature of the dark matter. A
number of more indirect methods are also discussed.


title: XMM-Newton Optical Monitor observations of LMC X-3

abstract:
  We study the optical counterpart of the black-hole X-ray binary LMC X-3, by
using XMM-Newton/OM observations carried out during a low-hard X-ray state. We
derive a better constraint for the temperature, mass and radius of the
companion star, and we show that the star is likely to be a ~ B5 subgiant
filling its Roche lobe. Taking into account the effect of X-ray irradiation, we
suggest a value f_M = (1.5 +/- 0.3) M_sun for the mass function in this system,
lower than previously thought; we provide a more accurate lower limit to the
mass of the compact object.


title:
Tidal streams in the Galactic halo: Evidence for the Sagittarius
  northern stream or traces of a new nearby dwarf galaxy

abstract:
  Standard cosmology predicts that dwarfs were the first galaxies to be formed
in the Universe and that many of them merge afterwards to form bigger galaxies
such as the Milky Way. This process would have left behind traces such as tidal
debris or star streams in the outer halo. We report here the detection of a
very low density stellar system at 50+/- 10 kpc from the Galactic center that
could be related to the merger process. It could form part of the Sagittarius
northern stream or, alternatively, could be the trace of a hitherto unknown
dwarf galaxy.
  The dwarf galaxy in Sagittarius, the closest satellite of the Milky Way, is
currently being tidally disrupted and is a ``living'' test for galaxy formation
theories. The system found here is 60 deg away from the center of the
Sagittarius galaxy. If it is really associated with this galaxy, it would
confirm predictions of dynamical interaction models indicating that tidal
debris from Sagittarius could extend along a stream completely enveloping the
Milky Way in a polar orbit.


title: A stellar fly-by simulation giving Beta Pic's disc asymmetries

abstract:
  We have numerically investigated the dynamics of how a close stellar fly-by
encounter of a symmetrical circumstellar planetesimal disc can give rise to the
many kinds of asymmetries and substructures attributed to the dusty disc of
Beta Pic. We find three recognizable groupings of test particles that can be
related to the morphology of the Beta Pic disc. These are: highly eccentric and
inclined orbit particles that reach apocentre in the southwest, moderately
eccentric and inclined orbit particles that reach apocentre in the northeast,
and a relatively unperturbed region inside ~200au radius.


title:
A Theoretical Model for the $M_{\rm bh}-\sigma$ Relation for
  Supermassive Black Holes in Galaxies

abstract:
  We construct a model for the formation of black holes within galactic bulges.
The initial state is a slowly rotating isothermal sphere, characterized by
effective transport speed $\aeff$ and rotation rate $\Omega$. The black hole
mass is determined when the centrifugal radius of the collapse flow exceeds the
capture radius of the central black hole. This model reproduces the observed
correlation between black hole masses and galactic velocity dispersions, $\mbh
\approx 10^8 M_\odot (\sigma/200 \kms)^4$, where $\sigma = \sqrt{2} \aeff$.
This model also predicts the ratio $\mrat$ of black hole mass to host mass:
$\mrat$ $\approx$ 0.004 $(\sigma/200 \kms)$.


title:
ISO continuum observations of quasars at z=1-4 I.Spectral energy
  distributions of quasars from the UV to far-infrared

abstract:
  Eight luminous quasars with $ -30 < M_B < -27$ at z = 1.4 - 3.7 have been
observed in the mid- and far-infrared using ISO. All the quasars have been
detected in the mid-infrared bands of ISOCAM, while no far-infrared detections
have been made with ISOPHOT. Supplementing ISO observations with photometry in
the optical and near-infrared made from the ground mostly within 17 months
after the ISO observations, SEDs (Spectral Energy Distributions) from the UV to
far-infrared have been obtained. SEDs (Spectral Energy Distributions) from the
UV to far-infrared have been obtained while supplementing ISO observations with
photometry in the optical and near-infrared made from the ground within 17
months. The SEDs are compared with the MED (Mean spectral Energy Distributions)
of low-redshift quasars with $-27 < M_B < -22$. It is shown that our
far-infrared observations were limited by confusion noise due to crowded
sources.


title:
Near-infrared Imaging and [O~I] spectroscopy of IC 443 using 2MASS and
  ISO

abstract:
  We present near-infrared J (1.25um), H (1.65um), and Ks (2.17um) imaging of
the entire supernova remnant IC 443 from the Two Micron All Sky Survey (2MASS),
and Infrared Space Observatory (ISO) LWS observations of [O I]. Near-infrared
emission from IC 443 was detected in all three bands from most of the optically
bright parts of the remnant, revealing a shell-like morphology, with bright Ks
band emission along the southern ridge and bright J and H along the
northeastern rim. The color and morphological structure are very different
between the northeastern and southern parts. J and H band emission from the
northeast rim is comparably bright and can be explained mostly by [Fe~II] line
emission. The southern ridge is dominated by Ks band light exhibiting a clumped
and knotty structure. Molecular hydrogen lines can explain most of K$_s$ band
and at least half of J and H band emission in the south. Hence, the prominent
broad-band color differences arise from physically different mechanisms: atomic
fine structure lines along the northeastern rim and molecular ro-vibrational
lines along the southern ridge. Shock models imply a fast J-shock with vs~100
km/s and 10<n<10^3 cm^-3 for the northeastern rim and a slow C-shock with vs
\~30 km/s and n~10^{4} cm^{-3} for the southern ridge, respectively.


title: Comparing and combining the Saskatoon, QMAP and COBE CMB maps

abstract:
  We present a method for comparing and combining maps with different
resolutions and beam shapes, and apply it to the Saskatoon, QMAP and COBE/DMR
data sets. Although the Saskatoon and QMAP maps detect signal at the 21 sigma
and 40 sigma levels, respectively, their difference is consistent with pure
noise, placing strong limits on possible systematic errors. In particular, we
obtain quantitative upper limits on relative calibration and pointing errors.
Splitting the combined data by frequency shows similar consistency between the
Ka- and Q-bands, placing limits on foreground contamination. The visual
agreement between the maps is equally striking. Our combined QMAP+Saskatoon
map, nicknamed QMASK, is publicly available at
www.hep.upenn.edu/~xuyz/qmask.html together with its 6495x6495 noise covariance
matrix. This thoroughly tested data set covers a large enough area (648 square
degrees -- currently the largest degree-scale map available) to allow a
statistical comparison with COBE/DMR, showing good agreement.


title: The Dawn of Galaxies: Deep MAMBO Imaging Surveys

abstract:
  We discuss results from sensitive, wide-field imaging of the millimeter
extragalactic background using the Max-Planck Millimeter Bolometer array
(MAMBO) at the IRAM 30m telescope.


title:
A High Resolution Method for Measuring Cosmic Ray Composition beyond 10
  TeV

abstract:
  The accurate determination of the elemental composition of cosmic rays at
high energies is expected to provide crucial clues on the origin of these
particles. Previous direct measurements of composition have been limited by
experiment collecting power, resulting in marginal statistics above $10^{14}$
eV, precisely the region where the ``knee'' of the cosmic-ray energy spectrum
is starting to develop. In contrast, indirect measurements using extensive air
showers can produce sufficient statistics in this region but generate elemental
measurements which have relatively large uncertainties. Here we discuss a
technique which has become possible through the use of modern ground-based
Cerenkov imaging detectors. We combine a measurement of the Cerenkov light
produced by the incoming cosmic-ray nucleus in the upper atmosphere with an
estimate of the total nucleus energy produced by the extensive air shower
initiated when the particle interacts deeper in the atmosphere. The emission
regions prior to and after the first hadronic interaction can be separated by
an imaging Cerenkov system with sufficient angular and temporal resolution.
Monte Carlo simulations indicate an expected charge resolution of $\Delta Z/Z
<5%$ for incident iron nuclei in the region of the ``knee'' of the cosmic-ray
energy spectrum. This technique also has the intriguing possibility to
unambiguously discover nuclei heavier than iron at energies above 10$^{14}$ eV.
The identification and rejection of background produced by charged particles in
ground based gamma-ray telescopes is also discussed.


title: No Persistent Pulsations in Aql X-1 as it Fades into Quiescence

abstract:
  We searched for coherent X-ray pulsations from Aql X-1 in a series of RXTE
observations taken shortly after a recent outburst. During the course of these
observations, Aql X-1 passes through an apparent ``propeller'' phase as its
luminosity fades to its quiescent value. No pulsations were detected, and we
place upper limits (ranging from 0.52% to 9.0%) on the fractional RMS amplitude
of any periodic signal contained in the various data sets searched. This result
has implications for the geometry of the system, if the quiescent luminosity is
due to continued low-level accretion. Alternatively, our result supports the
idea that the quiescent luminosity may be due to thermal emission.


title:
Kinematics of the ionized gas in the Local Group irregular galaxy IC
  1613

abstract:
  We present Halpha and [SII] observations for the Local Group irregular galaxy
IC 1613 using the PUMA scanning Fabry-Perot interferometer. Our goal is to
analyze the kinematics of the ionized gas in the complex sample of superbubbles
located in the whole extension of our field (10 arcmin), which includes most of
the optical emission of this galaxy, and to study the inter-relationship
between young stellar associations and nebulae based on a previous study that
we have made on the stellar associations of the central region of this galaxy.
The ionized gas in this galaxy is distributed in classical HII regions and in a
series of superbubbles (also called giant shells) covering a large fraction of
the optical extent of the galaxy. We present a catalog of kinematical
properties of both the HII regions of this galaxy and the superbubbles. We have
also compared the kinematics of the ionized gas in HII regions to search for
possible dynamic differences between neutral and ionized gas.


title: On the Astrometric Behavior of Binary Microlensing Events

abstract:
  Despite the suspected binarity for a significant fraction of Galactic lenses,
the current photometric surveys detected binary microlensing events only for a
small fraction of the total events. The detection efficiency is especially low
for non-caustic crossing events, which comprise majority of the binary lensing
events, due to the absence of distinctive features in their light curves
combined with small deviations from the standard light curve of a single
point-mass event. In addition, even they are detected, it will be difficult to
determine the solution of the binary lens parameters due to the severe
degeneracy problem. In this paper, we investigate the properties of binary
lensing events expected when they are astrometrically observed by using high
precision interferometers. For this, we construct vector field maps of excess
centroid shifts, which represent the deviations of the binary lensing centroid
shifts from those of a single lensing events as a function of source position.
  From the analysis of the maps, we find that the excess centroid shifts are
substantial in a considerably large area around caustics. In addition, they
have characteristic sizes and directions depending strongly on the source
positions with respect to the caustics and the resulting trajectories of the
light centroid (astrometric trajectories) have distinctive features, which can
be distinguished from the deviations caused by other reasons. We classify the
types of the deviations and investigate where they occur. Due to the strong
dependency of the centroid shifts on the lens system geometry combined with the
distinctive features in the observed astrometric trajectories, astrometric
binary lensing observations will provide an important tool that can probe the
properties of Galactic binary lens population.


title:
Mid-infrared imaging and spectroscopy of the enigmatic cocoon stars in
  the Quintuplet Cluster

abstract:
  In an attempt to determine the nature of the enigmatic cocoon stars in the
Quintuplet Cluster, we have obtained mid-infrared imaging and spectrophotometry
of the cluster, using the CAM and SWS instruments on ISO, using SpectroCam-10
on the Palomar 5m telescope, and NICMOS on HST. The spectra show smooth
continua with various dust and ice absorption features. These features are all
consistent with an interstellar origin, and there is no clear evidence for any
circumstellar contribution to these features. We find no spectral line or
feature that could elucidate the nature of these sources. Detailed modeling of
the silicate absorption features shows that they are best reproduced by the mu
Cep profile, which is typical of the interstellar medium, with tau(sil) \sim
2.9. The high spatial resolution mid-IR images show that three of the five
cocoon stars have spatially extended and asymmetric envelopes, with diameters
of \sim 20,000 AUs.
  A reddening law similar to that of Lutz (1999) but with silicate features
based on the mu Cep profile and normalized to our value of tau(sil) is used to
deredden the observed spectrophotometry. The dereddened energy distributions
are characterised by temperatures of 750-925 K, somewhat cooler than determined
from near IR data alone. Models of optically thin and geometrically thick dust
shells, as used by Williams et al. (1987) for very dusty, late-type WC stars,
reproduce the observed SEDs from 4 to 17 mic, and imply shell luminosities of
log(L/L(sun)) \sim 4.5-4.9 for the brightest four components. An analysis of
the various suggestions proposed to explain the nature of the cocoon stars
reveals serious problems with all the hypotheses, and the nature of these
sources remains an enigma.


title: Vacuum Selection by Collapsing

abstract:
  In this talk, we discuss the possibility that the vacuum is dynamically
determined in the history of the universe. The point is that some of the
bubbles with a certain vacuum shrink by the evolution of the universe via
gravity and may become black holes. It is interesting that in many cases false
vacua are favored in the context of cosmology. By using this argument,
supersymmetry(SUSY), if it exists, can be broken cosmologically. This talk is
based on Ref.[1].


title:
A jet model for the broadband spectrum of XTE J1118+480: Synchrotron
  emission from radio to X-rays in the Low/Hard spectral state

abstract:
  Observations have revealed strong evidence for powerful jets in the Low/Hard
states of black hole candidate X-ray binaries. Correlations, both temporal and
spectral, between the radio -- infrared and X-ray bands suggest that jet
synchrotron as well as inverse Compton emission could also be significantly
contributing at higher frequencies. We show here that, for reasonable
assumptions about the jet physical parameters, the broadband spectrum from
radio through X-rays can be almost entirely fit by synchrotron emission. We
explore a relatively simple model for a relativistic, adiabatically expanding
jet combined with a truncated thermal disk conjoined by an ADAF, in the context
of the recently discovered black hole binary XTE J1118+480. In particular, the
X-ray power-law emission can be explained as optically thin synchrotron
emission from a shock acceleration region in the innermost part of the jet,
with a cutoff determined by cooling losses. For synchrotron cooling-limited
particle acceleration, the spectral cutoff is a function only of dimensionless
plasma parameters and thus should be around a ``canonical'' value for sources
with similar plasma properties. It is therefore possible that non-thermal jet
emission is important for XTE J1118+480 and possibly other X-ray binaries in
the Low/Hard state.


title: Unbiased Reconstruction of the Large Scale Structure

abstract:
  We present a new Unbiased Minimal Variance (UMV) estimator for the purpose of
reconstructing the large--scale structure of the universe from noisy, sparse
and incomplete data. Similar to the Wiener Filter (WF), the UMV estimator is
derived by requiring the linear minimal variance solution given the data and an
assumed prior model specifying the underlying field covariance matrix. However,
unlike the WF, the minimization is carried out with the added constraint of an
unbiased reconstructed mean field. The new estimator does not necessitate a
noise model to estimate the underlying field; however, such a model is required
for evaluating the errors at each point in space. The general application of
the UMV estimator is to predict the values of the reconstructed field in
un-sampled regions of space (e.g., interpolation in the unobserved Zone of
Avoidance), and to dynamically transform from one measured field to another
(e.g., inversion of radial peculiar velocities to over-densities). Here, we
provide two very simple applications of the method. The first, is to recover a
1D signal from noisy, convolved data with gaps, e.g., CMB time-ordered data.
The second application is a reconstruction of the density and 3D peculiar
velocity fields from mock SEcat galaxy peculiar velocity catalogs.


title: Mining the local Universe: the QSO space density

abstract:
  We present progress results of a new survey for bright QSOs (V<14.5, R<15.4,
B_J<15.2) covering the whole sky at high galactic latitudes, |b|>30. The
surface density of QSOs brighter than B_J=14.8 turns out to be 2.9 +- 0.8
10^{-3} deg^{-2}. The optical Luminosity Function at 0.04 < z < 0.3 shows
significant departures from the standard pure luminosity evolution, providing
new insights in the modelling of the QSO phenomenon.


title:
How Frustrated Strings Would Pull the Black Holes from the Centers of
  Galaxies

abstract:
  Recently Pen and Spergel (1997) have shown that a universe whose energy
density is dominated by a frustrated network of non-Abelian TeV-scale cosmic
strings could account for a broad class of cosmological observations. In this
paper we consider the effects of such a string network on the massive black
holes widely believed to inhabit the centers of many galaxies. As these black
holes traverse the universe together with their host galaxies, they would
intersect a large number of string segments. We argue that such segments would
become stuck to the black hole, and be stretched by the hole's motion.
Stretching the strings would cause significant deceleration of the black holes.
Although the black holes would probably not be removed from the galaxies
completely, they would be noticeably displaced from the galactic center of mass
-- by at least 5kpc. This displacement seems to be is contradiction to the
observational evidence.


title: Gamma Ray Bursts, Cosmic Ray Origin, and the Unidentified EGRET Sources

abstract:
  Statistical arguments show that the volume- and time-averaged kinetic power
of GRBs and fireball transients (FTs) into an L* galaxy like the Milky Way is
at the level of 10^40 ergs/s. This number, though with wide uncertainties
related to the internal or external shock efficiency, is sufficient to power
hadronic cosmic rays observed locally. The release of energy by the high-mass
progenitor stars of GRBs and FTs is sufficient to power the ultrahigh energy
cosmic rays, as already shown by Waxman and Vietri in 1995. It is sufficient to
power the cosmic rays above the knee of the cosmic-ray spectrum. Indeed, all
hadronic cosmic rays could originate from the high-mass (>~ 100 M_o) stars that
collapse to black holes, in the process forming GRBs and FTs. This source class
represents a new solution to the problem of cosmic-ray origin. The ~10^4 - 10^7
black holes made by these stars could make their presence known by radiating as
they accrete from the ISM, by microlensing background radiations, and by
forming luminous binary systems. Some unidentified EGRET sources could be
isolated black holes that accrete from the ISM. Better imaging and sensitivity
with GLAST and TeV observatories will test this model for the unidentified
gamma-ray sources, and this theory for cosmic-ray origin.


title:
The Impact of Resolution on Observed HII Region Properties from WFPC2
  Observations of M101

abstract:
  Two continuum subtracted H-alpha HST frames of M101 are used to determine the
positions, angular sizes and absolute fluxes of 237 HII regions using a
semi-automated technique. From these we have constructed the luminosity and
diameter distribution functions.
  We repeat this process on the images after artificially reducing the linear
resolution to that typically obtained with ground based imaging. We find
substantial differences in the luminosity function and diameter distribution.
The measured internal properties, such as central surface brightness and radial
gradient are dominated by the PSF at linear resolutions less than roughly 40 pc
FWHM. From the ground such resolutions are currently only obtainable for the
nearest galaxies.
  We find evidence for two regimes of clustering of the HII regions and diffuse
emission, suggesting two different regimes of star formation in late type
spiral galaxies. This property in combination with the blending that occurs at
ground based resolutions might be responsible for the break in the luminosity
function which is usually found at log L=38.6 erg/s.
  From the high resolution HST data we find a luminosity function slope of
alpha=-1.74+/-0.08. We also observe a flattening at luminosities log L<36.7
erg/s. For the diameter distribution we find a characteristic scale of D0=29.2
pc from an exponential fit. However, a scale free power law with index
beta=-2.84+/-0.16 provides a better fit to the data.


title:
Identification of a complete sample of northern ROSAT All-sky survey
  X-ray sources. VII. The AGN subsample

abstract:
  In order to derive statistical properties of a complete X-ray selected sample
of AGN we used the classification spectra of the RASS Selected Areas-North
survey to study the luminosities, redshifts, X-ray/visual flux ratios, line
widths, and various correlations between observed parameters of all Seyfert
galaxies and QSOs in this sample. On the basis of these data we discuss
implications for the current AGN models.


title: The M 31 double nucleus probed with OASIS and HST. A natural m=1 mode?

abstract:
  We present observations with the adaptive optics assisted integral field
spectrograph OASIS of the M 31 double nucleus at a spatial resolution better
than 0.5 arcsec FWHM. These data are used to derive the two-dimensional stellar
kinematics within the central 2 arcsec. Archival WFPC2/HST images are revisited
to perform a photometric decomposition of the nuclear region. We also present
STIS/HST kinematics obtained from the archive. The luminosity distribution of
the central region is well separated into the respective contributions of the
bulge, the nucleus including P1 and P2, and the so-called UV peak. We then show
that the axis joining P1 and P2, the two local surface brightness maxima, does
not coincide with the kinematic major-axis, which is also the major-axis of the
nuclear isophotes (excluding P1). We also confirm that the velocity dispersion
peak is offset by ~ 0.2 arcsec from the UV peak, assumed to mark the location
of the supermassive black hole. The newly reduced STIS/HST velocity and
dispersion profiles are then compared to OASIS and other published kinematics.
We find significant offsets with previously published data. Simple parametric
models are then built to successfully reconcile all the available kinematics.
We finally interpret the observations using new N-body simulations. The nearly
keplerian nuclear disk of M31 is subject to a natural m=1 mode, with a very
slow pattern speed (3 km/s/pc for M_BH = 7 10^7~\Msun), that can be maintained
during more than a thousand dynamical times. The resulting morphology and
kinematics of the mode can reproduce the M~31 nuclear-disk photometry and mean
stellar velocity, including the observed asymmetries. It requires a central
mass concentration and a cold disk system representing between 20 and 40% of
its mass. Abridged..


title: Further detections of OH masers in carbon stars with silicate features

abstract:
  A sample of J-type carbon stars was searched for OH maser emission. The new
detection of three OH lines towards two silicate carbon stars is reported. In
V778 Cyg, previously known as the main-lines (1665 and 1667 MHz) maser source,
the satellite 1612 MHz emission was discovered while in NSV 2814 the main OH
lines were detected. The presence of OH maser lines confirms the former
suggestion that oxygen-rich material is located in the vicinity ($\approx$
$10^{15-16}$ cm) of silicate carbon stars.


title:
On the apparent coupling of neutral hydrogen and dark matter in spiral
  galaxies

abstract:
  We have studied a mass model for spiral galaxies in which the dark matter
surface density is a scaled version of the observed HI surface density.
Applying this mass model to a sample of 24 spiral galaxies with reliable
rotation curves one obtains good fits for most galaxies. The scaling factors
cluster around 7, after correction for the presence of primordial helium. But
for several cases different, often larger, values are found. For galaxies that
can not be fitted well the discrepancy occurs at large radii and results from a
fairly rapid decline of the HI surface density in the outermost regions.
Because of such imperfections and in view of possible selection effects it is
not possible to conclude here that there is a real coupling between HI and dark
matter in spiral galaxies.


title: Fueling the AGN

abstract:
  Active Galactic Nuclei are fueled from material (gas or stars) that are in
general far away from the gravitational influence of the central black hole,
the engine thought to be responsible for their activity. The required material
has a lot of angular momentum, that is a priori quite difficult to evacuate.
The various dynamical mechanisms that may play a role in this game are
reviewed, including m=2 perturbations (bars and spirals), m=1 perturbations
(spirals, warps, lopsidedness), and tidal interactions between galaxies and
mergers. In the latest stages of the merger, a binary black hole could be
formed, and its influence on the dynamics and fueling is discussed. Starbursts
are often associated with AGN, and the nature of their particular connection,
and their role in the nuclear fueling is described. Evolution of the fueling
efficiency with redshift is addressed.


title: Bumpy Power Spectra and dT/T

abstract:
  With the recent publication of the measurements of the radiation angular
power spectrum from the BOOMERanG Antarctic flight (de Bernardis et al. 2000),
it has become apparent that the currently favoured spatially-flat cold dark
matter model (matter density parameter $\Omega_{\rm m}=0.3$, flatness being
restored by a cosmological constant $\Omega_{\Lambda}=0.7$, Hubble parameter
$h=0.65$, baryon density parameter $\Omega_{\rm b}h^2=0.02$) no longer provides
a good fit to the data. We describe a phenomenological approach to resurrecting
this paradigm. We consider a primordial power spectrum which incorporates a
bump, arbitrarily placed at $k_{\rm b}$, and characterized by a Gaussian in log
$k$ of standard deviation $\sigma_{\rm b}$ and amplitude ${\rm A}_{\rm b}$,
that is superimposed onto a scale-invariant power spectrum. We generate a range
of theoretical models that include a bump at scales consistent with cosmic
microwave background and large-scale structure observations, and perform a
simple $\chi^2$ test to compare our models with the $COBE$ DMR data and the
recently published BOOMERanG and MAXIMA data. Unlike models that include a high
baryon content, our models predict a low third acoustic peak. We find that low
$\ell$ observations (20 $< \ell <$ 200) are a critical discriminant of the
bumps because the transfer function has a sharp cutoff on the high $\ell$ side
of the first acoustic peak...


title:
Charting the temperature of the Hot Neutron Star in a Soft X-ray
  Transient

abstract:
  We explore the thermal evolution of a neutron star undergoing episodes of
intense accretion, separated by long periods of quiescence. By using an exact
cooling code we follow in detail the flow of heat in the star due to the
time-dependent accretion-induced heating from pycno-nuclear reactions in the
stellar crust, to the surface photon emission, and the neutrino cooling. These
models allow us to study the neutron stars of the Soft X-Ray Transients. In
agreement with Brown, Bildsten and Rutledge (1998) we conclude that the soft
component of the quiescent luminosity of Aql X-1, 4U 1608-522, and of the
recently discovered SAX J1808.4, can be understood as thermal emission from a
cooling neutron star with negligible neutrino emission. However, we show that
in the case of Cen X-4, despite its long recurrence time, strong neutrino
emission from the neutron star inner core is necessary to understand the
observed low ratio of quiescent to outburst luminosity. This result implies
that the neutron star in Cen X-4 is heavier than the one in the other systems
and the pairing critical temperature in its center must be low enough (well
below 10^9 K) to avoid a strong suppression of the neutrino emission.


title:
The z=0.0912 and z=0.2212 Damped Lyman Alpha Galaxies Along the
  Sight-Line Toward the Quasar OI 363

abstract:
  New optical and infrared observations along the sight-line toward the quasar
OI 363 (0738+313) are presented and discussed. Excluding systems which lack
confirming UV spectroscopic observations of the actual Lyman alpha line, this
sight-line presently contains the two lowest-redshift classical damped Lyman
alpha (DLA) quasar absorption line systems known (i.e. with N(HI) \ge 2 x
10^{20} atoms cm^{-2}), one at z(abs)=0.0912 and the other at z(abs)=0.2212.
The z=0.09 DLA galaxy appears to be an extended low surface brightness galaxy
which is easily visible only in infrared images and shows rich morphological
structure. Subtraction of the quasar nuclear and host light yields L_K \approx
0.08L_K* at z=0.09. The impact parameter between the galaxy and quasar
sight-line is very small, b<3.6 kpc (<2 arcsec), which makes measurements
difficult. The z=0.22 DLA galaxy is an early-type dwarf with a K-band
luminosity of L_K \approx 0.1L_K* at impact parameter b=20 kpc. In general,
these results serve to support mounting evidence that DLA galaxies are drawn
from a wide variety of gas-rich galaxy types. (Abridged)


title: Dynamical Rotational Instability at Low $T/W$

abstract:
  Dynamical instability is shown to occur in differentially rotating polytropes
with N = 3.33 and $T/|W| \gtrsim 0.14$. This instability has a strong m=1 mode,
although the m=2, 3, and 4 modes also appear. Such instability may allow a
centrifugally-hung core to begin collapsing to neutron star densities on a
dynamical timescale. The gravitational radiation emitted by such unstable cores
may be detectable with advanced ground-based detectors, such as LIGO II. If the
instability occurs in a supermassive star, it may produce gravitational
radiation detectable by the space-based detector LISA.


title:
Relating Galaxy Cluster X-Ray Luminosities to Gravitational Masses in
  Wide Angle Surveys

abstract:
  It is shown that galaxy cluster surveys selecting clusters by their X-ray
luminosity effectively select by cluster mass. It is shown that a selection
based solely on Abell galaxy richness is less efficient in terms of mass.
Furthermore the empirical X-ray luminosity - gravitational mass relation and
its scatter is quantified and the relation is compared to predicted relations.


title: Planetary Torques as the Viscosity of Protoplanetary Disks

abstract:
  We revisit the idea that density-wave wakes of planets drive accretion in
protostellar disks. The effects of many small planets can be represented as a
viscosity if the wakes damp locally, but the viscosity is proportional to the
damping length. Damping occurs mainly by shocks even for earth-mass planets.
The excitation of the wake follows from standard linear theory including the
torque cutoff. We use this as input to an approximate but quantitative
nonlinear theory based on Burger's equation for the subsequent propagation and
shock. Shock damping is indeed local but weakly so. If all metals in a
minimum-mass solar nebula are invested in planets of a few earth masses each,
dimensionless viscosities [alpha] of order dex(-4) to dex(-3) result. We
compare this with observational constraints. Such small planets would have
escaped detection in radial-velocity surveys and could be ubiquitous. If so,
then the similarity of the observed lifetime of T Tauri disks to the
theoretical timescale for assembling a rocky planet may be fate rather than
coincidence.


title: Supernova Studies at ORLaND

abstract:
  A new facility to measure neutrino mass differences and mixing angles and
neutrino-nucleus cross sections, such as the proposed ORLaND facility at Oak
Ridge, would contribute to the experimental determination of vacuum mixing
parameters and would provide an experimental foundation for the many
neutrino-nucleus weak interaction rates needed in supernova models. This would
enable more realistic supernova models and a far greater ability to cull
fundamental physics from these models by comparing them with detailed
observations. Charged- and neutral-current neutrino interactions on nuclei in
the stellar core play a central role in supernova dynamics, nucleosynthesis,
and neutrino detection. Measurements of these reactions on select, judiciously
chosen targets would provide an invaluable test of the complex theoretical
models used to compute the neutrino-nucleus cross sections.


title: A Fractal Analysis of the HI Emission from the Large Magellanic Cloud

abstract:
  A composite map of HI in the LMC using the ATCA interferometer and the Parkes
multibeam telescope was analyzed in several ways in an attempt to characterize
the structure of the neutral gas and to find an origin for it. Fourier
transform power spectra in 1D, 2D, and in the azimuthal direction were found to
be approximate power laws over 2 decades in length. Delta-variance methods also
showed the same power-law structure. Detailed models of these data were made
using line-of-sight integrals over fractals that are analogous to those
generated by simulations of turbulence with and without phase transitions. The
results suggested a way to measure directly for the first time the
line-of-sight thickness of the cool component of the HI disk of a nearly
face-on galaxy. The signature of this thickness was found to be present in all
of the measured power spectra.
  The character of the HI structure in the LMC was also viewed by comparing
positive and negative images of the integrated emission. The geometric
structure of the high-emission regions was found to be filamentary, whereas the
geometric structure of the low-emission (intercloud) regions was found to be
patchy and round. This result suggests that compressive events formed the
high-emission regions, and expansion events, whether from explosions or
turbulence, formed the low-emission regions. The character of the structure was
also investigated as a function of scale using unsharp masks.
  All of these results suggest that most of the ISM in the LMC is fractal,
presumably the result of pervasive turbulence, self-gravity, and self-similar
stirring.


title:
Simulations of Stellar Core Collapse, Bounce, and Postbounce Evolution
  with Boltzmann Neutrino Transport, and Implications for the Core Collapse
  Supernova Mechanism

abstract:
  In this paper, we present results from a simulation of stellar core collapse,
bounce, and postbounce evolution with Boltzmann neutrino transport. We motivate
the development of our Boltzmann solver in light of the sensitivity of the
neutrino-heating core collapse supernova paradigm to details in the neutrino
transport, particularly near the neutrinospheres, where the neutrinos are
neither diffusing nor free streaming and a kinetic description is necessary,
and in light of the mixed outcomes and transport approximations used in all
prior supernova models in both one and two dimensions. We discuss the
implications of our findings for the supernova mechanism and future supernova
research. We also present the results of a Boltzmann transport prediction of
the early neutrino light curves in the model included here.


title: Toward a Standard Model of Core Collapse Supernovae

abstract:
  In this paper, we discuss the current status of core collapse supernova
models and the future developments needed to achieve significant advances in
understanding the supernova mechanism and supernova phenomenology, i.e., in
developing a supernova standard model.


title: Stellar winds from Massive Stars

abstract:
  We review the various techniques through which wind properties of massive
stars - O stars, AB supergiants, Luminous Blue Variables (LBVs), Wolf-Rayet
(WR) stars and cool supergiants - are derived. The wind momentum-luminosity
relation (e.g. Kudritzki et al. 1999) provides a method of predicting mass-loss
rates of O stars and blue supergiants which is superior to previous
parameterizations. Assuming the theoretical sqrt(Z) metallicity dependence,
Magellanic Cloud O star mass-loss rates are typically matched to within a
factor of two for various calibrations. Stellar winds from LBVs are typically
denser and slower than equivalent B supergiants, with exceptional mass-loss
rates during giant eruptions Mdot=10^-3 .. 10^-1 Mo/yr (Drissen et al. 2001).
Recent mass-loss rates for Galactic WR stars indicate a downward revision of
2-4 relative to previous calibrations due to clumping (e.g. Schmutz 1997),
although evidence for a metallicity dependence remains inconclusive (Crowther
2000). Mass-loss properties of luminous (> 10^5 Lo) yellow and red supergiants
from alternative techniques remain highly contradictory. Recent Galactic and
LMC results for RSG reveal a large scatter such that typical mass-loss rates
lie in the range 10^-6 .. 10^-4 Mo/yr, with a few cases exhibiting 10^-3 Mo/yr.


title: The Origin of The Stellar Initial Mass Function

abstract:
  Observations and theories of the stellar initial mass function are reviewed.
The universality and large total mass range of the power law portion of the IMF
suggest a connection between stellar mass and cloud structure. The fractal
patterns and formation times of young clusters suggest a further connection to
turbulence. There is also a similarity between the characteristic mass at the
lower end of the power law and the minimum self-gravitating mass in a typical
star-forming cloud. All of this suggests that the power law part of the IMF
comes from star formation in self-gravitating cloud pieces that are formed by
compressible turbulence. Timing constraints involving cloud destruction and
competition for gas might limit the upper stellar mass to several hundred suns.
This upper limit has to be less than the mass of a clump that has a dynamical
time equal to several times the dynamical time of the characteristic mass. The
smallest stars and brown dwarfs may not come directly from cloud clumps, which
are not self-gravitating at this mass in the cloudy phase, but from collapsed
fragments or other pieces connected with the formation of more massive stars.


title: Data Mining in Astronomical Databases

abstract:
  A Virtual Observatory (VO) will enable transparent and efficient access,
search, retrieval, and visualization of data across multiple data repositories,
which are generally heterogeneous and distributed. Aspects of data mining that
apply to a variety of science user scenarios with a VO are reviewed.


title: Effects of Preheating on X-ray Scaling Relations in Galaxy Clusters

abstract:
  The failure of purely gravitational models of X-ray cluster formation to
reproduce basic observed properties of the local cluster population suggests
the need for one or more additional physical processes operating on the
intracluster medium (ICM). We present results from 84 moderate resolution gas
dynamic simulations designed to systematically investigate the effects of
preheating - an initially elevated ICM adiabat - on the resultant, local X-ray
size-temperature, luminosity-temperature and ICM mass-temperature relations.
Seven sets of twelve simulations are performed for a LambdaCDM cosmology, each
set characterized by a different initial entropy level S_i. The slopes of the
observable relations steepen monotonically as S_i is increased. Observed slopes
for all three relations are reproduced by models with S_i: 55-150 keV cm^2,
levels that compare favorably to empirical determinations of core ICM entropy
by Lloyd-Davies, Ponman & Cannon. The redshift evolution for the case of a
locally successful model with S_i = 106 keV cm^2 is presented. At temperatures
kT > 3 keV, little or no evolution in physical isophotal sizes or bolometric
luminosities is expected to z < 1. The ICM mass at fixed T is lower at higher z
as expected in the canonical evolution model. ICM mass fractions show a mild T
dependence. Clusters with T > 3 keV contain ICM mass fractions depressed by
modest amounts (< 25%) below the cosmic mean baryon fraction Omega_b/Omega_m;
hot clusters subject to preheating remain good tracers of the cosmic mix of
clustered mass components.


title: Accurate masses of very low mass stars: III 16 new or improved masses

abstract:
  We have obtained adaptive optics images and accurate radial velocities for 7
very low mass systems, in the course of a long term effort to determine
accurate masses for very low mass stars (M<0.6 Solar Mass). We use the new
data, together with measurements from the litterature for some stars, to
determine new or improved orbits for these 7 systems. They provide masses for
16 very low mass stars with accuracies that range between 0.2% and 5%, and in
some cases a very accurate distance as well. This information is used in a
companion paper to discuss the Mass-Luminosity relation for the V, J, H and K
photometric bands.


title:
Accurate masses of very low mass stars: IV Improved mass-luminosity
  relations

abstract:
  We present improved visual and near-infrared empirical mass-luminosity
relations for very low mass stars (M$<$0.6~\Msol). These relations make use of
all stellar masses in this range known with better than 10% accuracy, most of
which are new determinations with 0.2 to 5% accuracy from our own programme,
presented in a companion paper.
  As predicted by stellar structure models, the metallicity dispersion of the
field populations induces a large scatter around the mean V band relation,
while the infrared relations are much tighter. The agreement of the observed
infrared mass-luminosity relations with the theoretical relations of Baraffe et
al. (1998) and Siess et al. (2000) is impressive, while we find an increasingly
significant discrepancy in the V band for decreasing masses. The theoretical
mass-luminosity relation which is insufficiently steep, and has introduced some
errors in the local stellar mass functions derived from V band luminosity
functions.


title: Simulations of galaxy formation in a cosmological volume

abstract:
  We present results of large N-body-hydrodynamic simulations of galaxy
formation. Our simulations follow the formation of galaxies in cubic volumes of
side 100Mpc, in two versions of the cold dark matter (CDM) cosmogony: the
standard, Omega=1 SCDM model and the flat, Omega=0.3 LCDM model. Over 2000
galaxies form in each of these simulations. We examine the rate at which gas
cools and condenses into dark matter halos. This roughly tracks the cosmic star
formation rate inferred from observations at various redshifts. Galaxies in the
simulations form gradually over time in the hierarchical fashion characteristic
of the CDM cosmogony. In the LCDM model, substantial galaxies first appear at
z=5 and the population builds up rapidly until z=1 after which the rate of
galaxy formation declines as cold gas is consumed and the cooling time of hot
gas increases. In both cosmologies, the present-day K-band luminosity function
of the simulated galaxies resembles observations. The galaxy autocorrelation
functions differ significantly from those of the dark matter. At the present
epoch there is little bias in either model between galaxies and dark matter on
large scales, but a significant anti-bias on scales of 1Mpc/h and a positive
bias on scales of 100kpc/h. The galaxy correlation function evolves little with
redshift in the range z=0-3, and depends on the luminosity of the galaxy
sample. The projected pairwise velocity dispersion of the galaxies is much
lower than that of the dark matter on scales less than 2Mpc/h. Applying a
virial mass estimator to the largest galaxy clusters recovers the cluster
virial masses in an unbiased way. (Abridged)


title: Cosmic Gamma-Ray Bursts as a Probe of Star Formation History

abstract:
  The cosmic gamma-ray burst (GRB) formation rate, as derived from the
variability-luminosity relation for long-duration GRBs, is compared with the
cosmic star formation rate. If GRBs are related to the collapse of massive
stars, one expects the GRB rate to be approximately proportional to the star
formation rate. We found that these two rates have similar slopes at low
redshift. This suggests that GRBs do indeed track the star formation rate of
the Universe, which in turn implies that the formation rate of massive stars
that produce GRBs is proportional to the total star formation rate. It also
implies that we might be able to use GRBs as a probe of the cosmic star
formation rate at high redshift. We find that the cosmic star formation rate
inferred from the variability-luminosity relation increases steeply with
redshift at z > 3. This is in apparent contrast to what is derived from
measurements of the cosmic star formation rate at high redshift from optical
observations of field galaxies, suggesting that much high-z star formation is
being missed in the optical surveys, even after corrections for dust extinction
have been made.


title: Variability of eta Carinae III

abstract:
  Spectra (1951-78) of the central object in eta Car, taken by A.D. Thackeray,
reveal three previously unrecorded epochs of low excitation. Since 1948, at
least, these states have occurred regularly in the 2020 day cycle proposed by
Damineli et al. They last about 10 percent of each cycle. Early slit spectra
(1899-1919) suggest that at that time the object was always in a low state.
JHKL photometry is reported for the period 1994-2000. This shows that the
secular increase in brightness found in 1972-94 has continued and its rate has
increased at the shorter wavelengths. Modulation of the infrared brightness in
a period near 2020 days continues. There is a dip in the JHKL light curves near
1998.0, coincident with a dip in the X-ray light curve. Evidence is given that
this dip in the infrared repeats in the 2020 day cycle. As suggested by
Whitelock & Laney, the dip is best interpreted as an eclipse phenomenon in an
interacting binary system; the object eclipsed being a bright region (`hot
spot'), possibly on a circumstellar disc or produced by interacting stellar
winds. The eclipse coincides in phase and duration with the state of low
excitation. It is presumably caused by a plasma column and/or by one of the
stars in the system.


title: Local Distance Indicators

abstract:
  A summary is given of the calibration of the Cepheid scale required in the
derivation of distances from observations at V and I, as in the HST work on
extragalactic Cepheids. There is some evidence that a small metallicity
correction may be necessary in deriving distances in this way. The evidence for
this comes both from observations of Cepheids of different metallicities and
from a comparison of the LMC distance modulus derived from Cepheids and that
derived by other methods.


title: Stars and black holes in varying speed of light theories

abstract:
  We investigate spherically symmetric solutions to a recently proposed
covariant and locally Lorentz-invariant varying speed of light theory. We find
the metrics and variations in $c$ associated with the counterpart of black
holes, the outside of a star, and stellar collapse. The remarkable novelty is
that $c$ goes to zero or infinity (depending on parameter signs) at the
horizon. We show how this implies that, with appropriate parameters, observers
are prevented from entering the horizon. Concomitantly stellar collapse must
end in a ``Schwarzchild radius'' remnant. We then find formulae for
gravitational light deflection, gravitational redshift, radar echo delay, and
the precession of the perihelion of Mercury, highlighting how these may differ
distinctly from their Einstein counterparts but still evade experimental
constraints. The main tell-tale signature of this theory is the prediction of
the observation of a different value for the fine structure constant, $\alpha$,
in spectral lines formed in the surface of stars. We close by mentioning a
variety of new classical and quantum effects near stars, such as aging
gradients and particle production.


title:
A Limit on the Polarized Anisotropy of the Cosmic Microwave Background
  at Subdegree Angular Scales

abstract:
  A ground-based polarimeter, PIQUE, operating at 90 GHz has set a new limit on
the magnitude of any polarized anisotropy in the cosmic microwave background.
The combination of the scan strategy and full width half maximum beam of 0.235
degrees gives broad window functions with average multipoles, l = 211+294-146
and l = 212+229-135 for the E- and B-mode window functions, respectively. A
joint likelihood analysis yields simultaneous 95% confidence level flat band
power limits of 14 and 13 microkelvin on the amplitudes of the E- and B-mode
angular power spectra, respectively. Assuming no B-modes, a 95% confidence
limit of 10 microkelvin is placed on the amplitude of the E-mode angular power
spectrum alone.


title:
Kinematics and photometry as complementary tools in the study of barred
  galaxies

abstract:
  Recent advances in observational techniques and theoretical modelling of
galaxy kinematics allow us to use more than just optical morphology to discern
the structure and dynamics of galaxies. Here, we show for three barred galaxies
(UGC 10205, NGC 6221 and NGC4340) that both kinematics and photometry are
necessary to fully understand the properties of these galaxies. Kinematic and
spectrophotometric data enable us to detect structures such as bars and gas
shocks that are not directly visible in the images; conversely, imaging can be
crucial for understanding the kinematic and dynamical behavior of a galaxy.


title: Rotation Curves of Spiral Galaxies

abstract:
  Rotation curves of spiral galaxies are the major tool for determining the
distribution of mass in spiral galaxies. They provide fundamental information
for understanding the dynamics, evolution and formation of spiral galaxies. We
describe various methods to derive rotation curves, and review the results
obtained. We discuss the basic characteristics of observed rotation curves in
relation to various galaxy properties, such as Hubble type, structure,
activity, and environment.


title: Central Rotation Curves of Galaxies

abstract:
  We emphasize the use of high-resolution CO line observations to derive
central rotation curves of galaxies. We present an example for high-resolution
interferometer observations of NGC 3079, and discuss the PV diagram and derived
rotation curve. The CO central rotation curves are combined with the outer
curves from \ha and HI-line observations to obtain total RC. We show that well
resolved RCs for massive galaxies generally start from non-zero velocities at
the nucleus.


title: Acceleration of the Universe as a consequence of gravitation properties

abstract:
  The analysis of the data from the distant supernovae (A.Riess et al,
Astron.J. {\bf 116}, 1009, (1988)) for acceleration of the expending Universe
from the viewpoint of the gravitation equations proposed by one of the authors
(Phys.Lett. {\bf 156}, 404 (1991)) is given. It is shown that the result from
the above data that the deceleration parameter $q_{0}$ is negative is a natural
consequence of the property of the gravitation force which follows from the
above gravitation equations . It is an alternative explanation to general
relativity where a nonzero cosmological constant is used to explain the data.


title:
Ultra-High-Density Molecular Core and Warped Nuclear Disk in the Deep
  Potential of Radio-Lobe Galaxy NGC 3079

abstract:
  We have performed high-resolution synthesis observations of the 12CO (J=1-0)
line emission from the radio lobe edge-on spiral NGC 3079 using a 7-element
mm-wave interferometer at Nobeyama, which consisted of the 45-m telescope and
6-element Array. The molecular nuclear disk (NMD) of 750 pc radius is found to
be inclined by 20 degrees from the optical disk, and the NMD has spiral arms.
An ultra-high-density molecular core (UHC) was found at the nucleus. The
gaseous mass of the UHC within 125 pc radius is as large as about 3 x 10^8
Msun, an order of magnitude more massive than that in the same area of the
Galactic Center, and the mean density is as high as approximately 3 x 10^3 H2
cm^-3. A position-velocity diagram along the major axis indicates that the
rotation curve starts at a finite velocity exceeding 300 \kms already from the
nucleus. The surface mass density in the central region is estimated to be as
high as about 10^5 Msun pc^-2, producing a very deep gravitational potential.
We argue that the very large differential rotation in such a deep potential
will keep the UHC gravitationally stable from current star formation.


title:
Searching for Supersymmetric Dark Matter- The Modulation Effect Due to
  Caustc Rings

abstract:
  The detection of the theoretically expected dark matter is central to
particle physics and cosmology. Current fashionable supersymmetric models
provide a natural dark matter candidate which is the lightest supersymmetric
particle (LSP). The theoretically obtained event rates are usually very low or
even undetectable. So the experimentalists would like to exploit the modulation
effect. In the present paper we study a specific class of non-isothermal models
involving flows of caustic rings. We find that the modulation effect arising
from such models is smaller than that predicted by the isothermal models.


title: Discovery of Two Relativistic Neutron Star-White Dwarf Binaries

abstract:
  We have discovered two recycled pulsars in relativistic orbits as part of the
first high-frequency survey of intermediate Galactic latitudes. PSR J1157-5112
is a 44 ms pulsar and the first recycled pulsar with an ultra-massive (M > 1.14
Mo) white dwarf companion. Millisecond pulsar J1757-5322 is a relativistic
circular-orbit system which will coalesce due to the emission of gravitational
radiation in less than 9.5 Gyr. Of the ~40 known circular orbit pulsars,
J1757-5322 and J1157-5112 have the highest projected orbital velocities. There
are now three local neutron-star/white-dwarf binaries that will coalesce in
less than a Hubble time, implying a large coalescence rate for these objects in
the local Universe. Systems such as J1141-6545 (Kaspi et al. 2000) are
potential gamma-ray burst progenitors and dominate the coalescence rate, whilst
lighter systems make excellent progenitors of millisecond pulsars with
planetary or ultra-low mass companions.


title: Are Cluster Radio Relics Revived Fossil Radio Cocoons?

abstract:
  A new model for the, so called, `cluster radio relics' is presented (Ensslin
& Gopal-Krishna 2000). Fossil radio cocoons, resulting from the former activity
of radio galaxies, should contain a low energy relativistic electron population
and magnetic fields. Electrons with an age of even up to 2 Gyr can be
re-accelerated adiabatically to radio emitting energies, if the fossil radio
plasma gets compressed in an environmental shock wave. Such a wave can be
caused by a merging event of galaxy clusters, or by the accretion onto galaxy
clusters. An implication of this model is the existence of a population of
diffuse, ultra-steep spectrum, very low-frequency radio sources located inside
and possibly outside of clusters of galaxies, tracing the revival of aged
fossil radio plasma by the shock waves associated with large-scale structure
formation.