title: Multi-band study of NGC 7424 and its two newly-discovered ULXs

abstract:
  We have studied the face-on, barred spiral NGC 7424 (site of the rare Type
IIb SN 2001ig) with Chandra, Gemini and the Australia Telescope Compact Array.
After giving revised X-ray colours and luminosity of the supernova, here we
focus on some other interesting sources in the galaxy: in particular, our
serendipitous discovery of two ultraluminous X-ray sources (ULXs). The brighter
one (~ 10^{40} erg/s) has a power-law-like spectrum with photon index Gamma ~
1.8. The other ULX shows a spectral state transition or outburst between the
two Chandra observations, 20 days apart. Optical data show that this ULX is
located in a young (age ~ 7-10 Myr), bright complex rich with OB stars and
clusters. An exceptionally bright, unresolved radio source (0.14 mJy at 4.79
GHz, implying a radio luminosity twice as high as Cas A) is found slightly
offset from the ULX (~ 80 pc). Its radio spectral index alpha ~ -0.7 suggests
optically-thin synchrotron emission, either from a young supernova remnant or
from a radio lobe powered by a ULX jet. An even brighter, unresolved radio
source (0.22 mJy at 4.79 GHz) is found in another young, massive stellar
complex, not associated with any X-ray sources: based on its flatter radio
spectral index (alpha ~ -0.3), we suggest that it is a young pulsar wind
nebula, a factor of 10 more radio luminous than the Crab.


title: Orbital Evolution of Algol Binaries with a Circumbinary Disk

abstract:
  It is generally thought that conservative mass transfer in Algol binaries
causes their orbits to be wider, in which the less massive star overflows its
Roche-lobe. The observed decrease in the orbital periods of some Algol binaries
suggests orbital angular momentum loss during the binary evolution, and the
magnetic braking mechanism is often invoked to explain the observed orbital
shrinkage. Here we suggest an alternative explanation, assuming that a small
fraction of the transferred mass forms a circumbinary disk, which extracts
orbital angular momentum from the binary through tidal torques. We also perform
numerical calculations of the evolution of Algol binaries with typical initial
masses and orbital periods. The results indicate that, for reasonable input
parameters, the circumbinary disk can significantly influence the orbital
evolution, and cause the orbit to shrink on a sufficiently long timescale.
Rapid mass transfer in Algol binaries with low mass ratios can also be
accounted for in this scenario.


title:
Time Variations of the Superkamiokande Solar Neutrino Flux Data by
  Rayleigh Power Spectrum Analysis

abstract:
  We have used the Rayleigh Power Spectrum Analysis of the solar neutrino flux
data from 1) 5-day-long samples from Super-Kamiokande-I detector during the
period from June, 1996 to July, 2001; 2) 10 -day-long samples from the same
detector during the same period and (3) 45-day long from the same detector
during the same period. According to our analysis (1) gives periodicities
around 0.25, 23.33, 33.75 and 42.75 months; (2) exhibits periodicities around
0.5, 1.0, 28.17, 40.67 and 52.5 months and (3) shows periodicities around 16.5
and 28.5 months. We have found almost similar periods in the solar flares,
sunspot data, solar proton data.


title:
Time Variations of the Solar Neutrino Flux Data from Sage and Gallex-Gno
  Detectors Obtained by Rayleigh Power Spectrum Analysis

abstract:
  We have used Rayleigh power spectrum analysis of the monthly solar neutrino
flux data from (1) SAGE detector during the period from 1st January 1990 to
31st December 2000; (2) SAGE detector during the period from April 1998 to
December 2001; (3) GALLEX detector during the period from May 1991 to January
1997; (4) GNO detector during the period from May 1998 to December 2001; (5)
GALLEX-GNO detector (combined data) from May 1991 to December 2001 and (6)
average of the data from GNO and SAGE detectors during the period from May 1998
to December 2001. (1) exhibits periodicity around 1.3, 4.3, 5.5, 6.3, 7.9, 8.7,
15.9, 18.7, 23.9, 32.9 and 48.7 months. (2) shows periodicity around 1.5, 2.9,
4.5, 10.1 months. For (3) we observe periodicity around 1.7, 18.7 and 26.9
months. For (4) periodicity is seen around 3.5, 5.5, 7.7 and 10.5 months. (5)
gives periodicity around 1.7, 18.5, 28.5 and 42.1 months while (6) shows
periodicity around 4.3, 6.9, 10.3 and 18.1 months. We have found almost similar
periods in the solar flares, sunspot data, solar proton data which indicates
that the solar activity cycle may be due to the variable character of nuclear
energy generation inside the sun.


title:
Quasars Probing Quasars II: The Anisotropic Clustering of Optically
  Thick Absorbers around Quasars

abstract:
  With close pairs of quasars at different redshifts, a background quasar
sightline can be used to study a foreground quasar's environment in absorption.
We used a sample of 17 Lyman limit systems with column density N_HI > 10^19
cm^-2 selected from 149 projected quasar pair sightlines, to investigate the
clustering pattern of optically thick absorbers around luminous quasars at z ~
2.5. Specifically, we measured the quasar-absorber correlation function in the
transverse direction, and found a comoving correlation length of
r_0=9.2_{+1.5}_{-1.7} Mpc/h (comoving) assuming a power law correlation
function, with gamma=1.6. Applying this transverse clustering strength to the
line-of-sight, would predict that ~ 15-50% of all quasars should show a N_HI >
10^19 cm^-2 absorber within a velocity window of v < 3000 km/s. This
overpredicts the number of absorbers along the line-of-sight by a large factor,
providing compelling evidence that the clustering pattern of optically thick
absorbers around quasars is highly anisotropic. The most plausible
explanationfor the anisotropy is that the transverse direction is less likely
to be illuminated by ionizing photons than the line-of-sight, and that
absorbers along the line-of-sight are being photoevaporated. A simple model for
the photoevaporation of absorbers subject to the ionizing flux of a quasar is
presented, and it is shown that absorbers with volume densities n_H < 0.1 cm^-3
will be photoevaporated if they lie within ~ 1 Mpc (proper) of a luminous
quasar. Using this simple model, we illustrate how comparisons of the
transverse and line-of-sight clustering around quasars can ultimately be used
to constrain the distribution of gas in optically thick absorption line
systems.


title: X-ray Timing beyond the Rossi X-ray Timing Explorer

abstract:
  With its ability to look at bright galactic X-ray sources with
sub-millisecond time resolution, the Rossi X-ray Timing Explorer (RXTE)
discovered that the X-ray emission from accreting compact stars shows
quasi-periodic oscillations on the dynamical timescales of the strong field
region. RXTE showed also that waveform fitting of the oscillations resulting
from hot spots at the surface of rapidly rotating neutron stars constrain their
masses and radii. These two breakthroughs suddenly opened up a new window on
fundamental physics, by providing new insights on strong gravity and dense
matter. Building upon the RXTE legacy, in the Cosmic Vision exercise, testing
General Relativity in the strong field limit and constraining the equation of
state of dense matter were recognized recently as key goals to be pursued in
the ESA science program for the years 2015-2025. This in turn identified the
need for a large (10 m2 class) aperture X-ray observatory. In recognition of
this need, the XEUS mission concept which has evolved into a single launch L2
formation flying mission will have a fast timing instrument in the focal plane.
In this paper I will outline the unique science that will be addressed with
fast X-ray timing on XEUS.


title: Light Curves of Swift Gamma Ray Bursts

abstract:
  Recent observations from the Swift gamma-ray burst mission indicate that a
fraction of gamma ray bursts are characterized by a canonical behaviour of the
X-ray afterglows. We present an effective theory which allows us to account for
X-ray light curves of both (short - long) gamma ray bursts and X-ray rich
flashes. We propose that gamma ray bursts originate from massive magnetic
powered pulsars.


title:
A sensitive survey for water maser emission towards Bok globules using
  the Robledo 70m antenna

abstract:
  We report the most sensitive water maser survey towards Bok globules to date,
using NASA's 70m antenna in Robledo de Chavela (Spain). We observed 207
positions within the CB catalog with a higher probability of harboring a young
star, using as selection criteria the presence of radio continuum emission
(from submillimeter to centimeter wavelengths), geometrical centers of
molecular outflows, peaks in maps of high-density gas tracers (NH3 or CS), and
IRAS point sources. We have obtained 7 maser detections, 6 of which (in CB 34,
CB 54, CB 65, CB 101, CB 199, and CB 232) are reported for the first time here.
Most of the water masers we detected are likely to be associated with young
stellar objects (YSOs), except for CB 101 (probably an evolved object) and CB
65 (uncertain nature). The water maser in CB 199 shows a relatively high shift
(~30 km/s) of its velocity centroid with respect to the cloud velocity, which
is unusual for low-mass YSOs. We speculate that high-velocity masers in this
kind of object could be related with episodes of energetic mass-loss in close
binaries. Alternatively, the maser in CB 199 could be pumped by a
protoplanetary or a young planetary nebula. CB 232 is the smallest Bok globule
(~0.6 pc) known to be associated with water maser emission, although it would
be superseded by the cases of CB 65 (~0.3 pc) and CB 199 (~0.5 pc) if their
association with YSOs is confirmed. All our selection criteria have
statistically compatible detection rates, except for IRAS sources, which tend
to be a somewhat worse predictor for the presence of maser emission.


title:
A re-analysis of the three-year WMAP temperature power spectrum and
  likelihood

abstract:
  We analyze the three-year WMAP temperature anisotropy data seeking to confirm
the power spectrum and likelihoods published by the WMAP team. We apply five
independent implementations of four algorithms to the power spectrum estimation
and two implementations to the parameter estimation. Our single most important
result is that we broadly confirm the WMAP power spectrum and analysis. Still,
we do find two small but potentially important discrepancies: On large angular
scales there is a small power excess in the WMAP spectrum (5-10% at l<~30)
primarily due to likelihood approximation issues between 13 <= l <~30. On small
angular scales there is a systematic difference between the V- and W-band
spectra (few percent at l>~300). Recently, the latter discrepancy was explained
by Huffenberger et al. (2006) in terms of over-subtraction of unresolved point
sources. As far as the low-l bias is concerned, most parameters are affected by
a few tenths of a sigma. The most important effect is seen in n_s. For the
combination of WMAP, Acbar and BOOMERanG, the significance of n_s =/ 1 drops
from ~2.7 sigma to ~2.3 sigma when correcting for this bias. We propose a few
simple improvements to the low-l WMAP likelihood code, and introduce two
important extensions to the Gibbs sampling method that allows for proper
sampling of the low signal-to-noise regime. Finally, we make the products from
the Gibbs sampling analysis publically available, thereby providing a fast and
simple route to the exact likelihood without the need of expensive matrix
inversions.


title:
Solar dynamo models with alpha-effect and turbulent pumping from local
  3D convection calculations

abstract:
  (abridged) Results from kinematic solar dynamo models employing alpha-effect
and turbulent pumping from local convection calculations are presented. We
estimate the magnitude of these effects to be around 2-3 m/s. The rotation
profile of the Sun as obtained from helioseismology is applied. We obtain an
estimate of the ratio of the two induction effects, C_alpha/C_Omega \approx
10^-3, which we keep fixed in all models. We also include a one-cell meridional
circulation pattern having a magnitude of 10-20 m/s near the surface and 1-2
m/s at the bottom of the convection zone. The model essentially represents a
distributed turbulent dynamo, as the alpha-effect is nonzero throughout the
convection zone, although it concentrates near the bottom of the convection
zone obtaining a maximum around 30 degrees of latitude. Turbulent pumping of
the mean fields is predominantly down- and equatorward. We find that, when all
these effects are included in the model, it is possible to correctly reproduce
many features of the solar activity cycle, namely the correct equatorward
migration at low latitudes and the polar branch at high latitudes, and the
observed negative sign of B_r B_phi. Although the activity clearly shifts
towards the equator in comparison to previous models due to the combined action
of the alpha-effect peaking at midlatitudes, meridional circulation and
latitudinal pumping, most of the activity still occurs at too high latitudes
(between 5-60 degrees). Other problems include the relatively narrow parameter
space within which the preferred solution is dipolar (A0), and the somewhat too
short cycle lengths of the solar-type solutions. The role of the surface shear
layer is found to be important only in the case where the alpha-effect has an
appreciable magnitude near the surface.


title:
Cosmic reionization constraints on the nature of cosmological
  perturbations

abstract:
  We study the reionization history of the Universe in cosmological models with
non-Gaussian density fluctuations, taking them to have a renormalized $\chi^2$
probability distribution function parametrized by the number of degrees of
freedom, $\nu$. We compute the ionization history using a simple
semi-analytical model, considering various possibilities for the astrophysics
of reionization. In all our models we require that reionization is completed
prior to $z=6$, as required by the measurement of the Gunn--Peterson optical
depth from the spectra of high-redshift quasars. We confirm previous results
demonstrating that such a non-Gaussian distribution leads to a slower
reionization as compared to the Gaussian case. We further show that the recent
WMAP three-year measurement of the optical depth due to electron scattering,
$\tau=0.09 \pm 0.03$, weakly constrains the allowed deviations from Gaussianity
on the small scales relevant to reionization if a constant spectral index is
assumed. We also confirm the need for a significant suppression of star
formation in mini-halos, which increases dramatically as we decrease $\nu$.


title: Failed disk winds; a physical origin for the soft X-ray excess?

abstract:
  The origin of the soft X-ray excess emission observed in many type-1 AGN has
been an unresolved problem in X-ray astronomy for over two decades. We develop
the model proposed Gierlinski & Done (2004), which models the soft excess with
heavily smeared, ionized, absorption, by including the emission that must be
associated with this absorption. We show that, rather than hindering the
ionized absorption model, the addition of the emission actually helps this
model reproduce the soft excess. The emission fills in some of the absorption
trough, while preserving the sharp rise at ~1 keV, allowing the total model to
reproduce the soft excess curvature from a considerably wider range of model
parameters. We demonstrate that this model is capable of reproducing even the
strongest soft X-ray excesses by fitting it to the XMM-Newton EPIC PN spectrum
of PG1211+143, with good results. The addition of the emission reduces the
column density required to fit these data by a factor ~2 and reduces the
smearing velocity from ~0.28c to ~0.2c. Gierlinski & Done suggested a tentative
origin for the absorption in the innermost, accelerating, region of an
accretion disk wind, and we highlight the advantages of this interpretation in
comparison to accretion disk reflection models of the soft excess. Associating
this material with a wind off the accretion disk results in several separate
problems however, namely, the radial nature, and the massive implied mass-loss
rate, of the wind. We propose an origin in a 'failed wind', where the central
X-ray source is strong enough to over-ionize the wind, removing the
acceleration through line absorption before the material reaches escape
velocity, allowing the material to fall back to the disk at larger radii.


title: Analysis of RR Lyrae Stars in the Northern Sky Variability Survey

abstract:
  We use data from the Northern Sky Variability Survey (NSVS), obtained from
the first generation Robotic Optical Transient Search Experiment (ROTSE-I), to
identify and study RR Lyrae variable stars in the solar neighborhood. We
initially identified 1197 RRab (RR0) candidate stars brighter than the ROTSE
median magnitude V = 14. Periods, amplitudes, and mean V magnitudes are
determined for a subset of 1188 RRab stars with well defined light curves.
Metallicities are determined for 589 stars by the Fourier parameter method and
by the relationship between period, amplitude, and [Fe/H]. We comment upon the
difficulties of clearly classifying RRc (RR1) variables in the NSVS dataset.
Distances to the RRab stars are calculated using an adopted
luminosity-metallicity relation with corrections for interstellar extinction.
The 589 RRab stars in our final sample are used to study the properties of the
RRab population within 5 kpc of the Sun. The Bailey diagram of period versus
amplitude shows that the largest component of this sample belongs to Oosterhoff
type I. Metal-rich ([Fe/H] > -1) RRab stars appear to be associated with the
Galactic disk. Our metal-rich RRab sample may include a thin disk as well as a
thick disk population, although the uncertainties are too large to establish
this. There is some evidence among the metal-rich RRab stars for a decline in
scale height with increasing [Fe/H], as was found by Layden (1995). The
distribution of RRab stars with -1 < [Fe/H] < -1.25 indicates that within this
metallicity range the RRab stars are a mixture of stars belonging to halo and
disk populations.


title:
Ultra-Dense Neutron Star Matter, Strange Quark Stars, and the Nuclear
  Equation of State

abstract:
  With central densities way above the density of atomic nuclei, neutron stars
contain matter in one of the densest forms found in the universe. Depending of
the density reached in the cores of neutron stars, they may contain stable
phases of exotic matter found nowhere else in space. This article gives a brief
overview of the phases of ultra-dense matter predicted to exist deep inside
neutron stars and discusses the equation of state associated with such matter.


title: Formation of giant planets around stars with various masses

abstract:
  We examine the predictions of the core accretion - gas capture model
concerning the efficiency of planet formation around stars with various masses.
First, we follow the evolution of gas and solids from the moment when all
solids are in the form of small grains to the stage when most of them are in
the form of planetesimals. We show that the surface density of the planetesimal
swarm tends to be higher around less massive stars. Then, we derive the minimum
surface density of the planetesimal swarm required for the formation of a giant
planet both in a numerical and in an approximate analytical approach. We
combine these results by calculating a set of representative disk models
characterized by different masses, sizes, and metallicities, and by estimating
their capability of forming giant planets. Our results show that the set of
protoplanetary disks capable of giant planet formation is larger for less
massive stars. Provided that the distribution of initial disk parameters does
not depend too strongly on the mass of the central star, we predict that the
percentage of stars with giant planets should increase with decreasing stellar
mass. Furthermore, we identify the radial redistribution of solids during the
formation of planetesimal swarms as the key element in explaining these
effects.


title: The NIR Upgrade to the SALT Robert Stobie Spectrograph

abstract:
  The near infrared (NIR) upgrade to the Robert Stobie Spectrograph (RSS) on
the Southern African Large Telescope (SALT), RSS/NIR, extends the spectral
coverage of all modes of the visible arm. The RSS/NIR is a low to medium
resolution spectrograph with broadband imaging, spectropolarimetric, and
Fabry-Perot imaging capabilities. The visible and NIR arms can be used
simultaneously to extend spectral coverage from approximately 3200 A to 1.6 um.
Both arms utilize high efficiency volume phase holographic gratings via
articulating gratings and cameras. The NIR camera is designed around a
2048x2048 HAWAII-2RG detector housed in a cryogenic dewar. The Epps optical
design of the camera consists of 6 spherical elements, providing sub-pixel rms
image sizes of 7.5 +/- 1.0 um over all wavelengths and field angles. The exact
long wavelength cutoff is yet to be determined in a detailed thermal analysis
and will depend on the semi-warm instrument cooling scheme. Initial estimates
place instrument limiting magnitudes at J = 23.4 and H(1.4-1.6 um) = 21.6 for
S/N = 3 in a 1 hour exposure well below the sky noise.


title: A Spitzer Infrared Radius for the Transiting Extrasolar Planet HD209458b

abstract:
  We have measured the infrared transit of the extrasolar planet HD209458b
using the Spitzer Space Telescope. We observed two primary eclipse events (one
partial and one complete transit) using the 24 micron array of the Multiband
Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual
images (10-second integrations) of the planetary system, recorded before,
during, and after transit. We perform optimal photometry on the images and use
the local zodiacal light as a short-term flux reference. At this long
wavelength, the transit curve has a simple box-like shape, allowing robust
solutions for the stellar and planetary radii independent of stellar limb
darkening, which is negligible at 24 microns. We derive a stellar radius of
R$_*$ = 1.06 $\pm$ 0.07 R$_\sun$, a planetary radius of R$_p$ = 1.26 $\pm$ 0.08
R$_J$, and a stellar mass of 1.17 M$_\sun$. Within the errors, our results
agree with the measurements at visible wavelengths. The 24-micron radius of the
planet therefore does not differ significantly compared to the visible result.
We point out the potential for deriving extrasolar transiting planet radii to
high accuracy using transit photometry at slightly shorter IR wavelengths where
greater photometric precision is possible.


title: Long RXTE Observations of A2163

abstract:
  A2163 was observed by the RXTE satellite for 530 ks during a 6 month period
starting in August 2004. The cluster primary emission is from very hot
intracluster gas with kT~15 keV, but this component does not by itself provide
the best fitting model. A secondary emission component is quite clearly needed,
and while this could also be thermal at a temperature significantly lower than
kT~15 keV, the best fit (to the combined PCA and HEXTE datasets) is obtained
with a power law secondary spectral component. The deduced parameters of the
non-thermal (NT) emission imply a significant fractional flux amounting to ~25%
of the integrated 3-50 keV emission. NT emission is expected given the intense
level of radio emission, most prominently from a large extended (`halo')
central region of the cluster. Interpreting the deduced NT emission as Compton
scattering of the radio-emitting relativistic electrons by the CMB, we estimate
the volume-averaged value of the magnetic field in the extended radio region to
be B=0.4+/-0.2 microG.


title:
Using Galaxy Two-point Correlation Functions to Determine the Redshift
  Distributions of Galaxies Binned by Photometric Redshift

abstract:
  We investigate how well the redshift distributions of galaxies sorted into
photometric redshift bins can be determined from the galaxy angular two-point
correlation functions. We find that the uncertainty in the reconstructed
redshift distributions depends critically on the number of parameters used in
each redshift bin and the range of angular scales used, but not on the number
of photometric redshift bins. Using six parameters for each photometric
redshift bin, and restricting ourselves to angular scales over which the galaxy
number counts are normally distributed, we find that errors in the
reconstructed redshift distributions are large; i.e., they would be the
dominant source of uncertainty in cosmological parameters estimated from
otherwise ideal weak lensing or baryon acoustic oscillation data. However,
either by reducing the number of free parameters in each redshift bin, or by
(unjustifiably) applying our Gaussian analysis into the non-Gaussian regime, we
find that the correlation functions can be used to reconstruct the redshift
distributions with moderate precision; e.g., with mean redshifts determined to
around 0.01. We also find that dividing the galaxies into two spectral types,
and thereby doubling the number of redshift distribution parameters, can result
in a reduction in the errors in the combined redshift distributions.


title: On the Lyman-alpha and Lyman-beta lines in solar coronal streamers

abstract:
  We investigate the formation of the H I Lyman-alpha and Lyman-beta lines in
an equatorial coronal streamer. Particular attention is paid to frequency
redistribution for the scattering of the incident radiation. The properties of
the spectral lines are studied. The coronal model is given by a global 2.5-D
three fluid solar wind model with alpha particles. The emergent intensities and
line profiles are calculated from the solution of the statistical equilibrium
and radiative transfer equations for an hydrogen atom with 11 energy levels
under non local thermodynamic equilibrium. The formation of the lines results
from radiative excitation, collisional excitation, and takes into account the
coupling with all other transitions between the hydrogen energy levels. We
present new estimates of the radiative and collisional contributions of the
Lyman line intensities within the streamer. It is also shown that within the
streamer, the full width at half-maximum (FWHM) of the Lyman-beta line is a
better indicator of the plasma temperature than that of Lyman-alpha. These
results show that care should be taken when inferring the proton temperature
from the Lyman-alpha line profile as observed in coronal streamers, e.g. by the
Ultraviolet Coronagraph Spectrometer or the Solar Ultraviolet Measurements of
Emitted Radiation experiments on board the Solar and Heliospheric Observatory.


title: Quasar Structure and Cosmological Feedback

abstract:
  Feedback from quasars and AGNs is being invoked frequently in several
cosmological settings. Currently, order of magnitude, or more, uncertainties in
the structure of both the wind and the 'obscuring torus' make predictions
highly uncertain. To make testable models of this 'cosmological feedback' it is
essential to understand the detailed structure of AGNs sufficiently well to
predict their properties for the whole quasar population, at all redshifts.
Progress in both areas is rapid, and I describe the near-term prospects for
reducing these uncertainties for 'slow' (non-relativistic) AGN winds and the
obscuring torus.


title:
On the formation of extended galactic disks by tidally disrupted dwarf
  galaxies

abstract:
  We explore the possibility that extended disks, such as that recently
discovered in M31, are the result of a single dwarf (10^9--10^10 Msun)
satellite merger. We carry out N-body simulations of dwarf NFW halos with
embedded spheriodal stellar components on co-planar, prograde orbits in a
M31-like host galaxy. As the orbit decays due to dynamical friction and the
system is disrupted, the stellar particles form an extended, exponential
disk-like structure that spans the radial range 30--200 kpc once they have
relaxed. The disk scale-length correlates with the initial extent of the
stellar component within the satellite halo: the more embedded the stars, the
smaller the resulting disk scale-length. If the progenitors start on circular
orbits, the kinematics of the stars that make up the extended disk have an
average rotational motion that is 30--50 km/s lower than the host's circular
velocity. For dwarf galaxies moving on highly eccentric orbits (e=0.7), the
stellar debris exhibits a much lower rotational velocity. Our results imply
that extended galactic disks might be a generic feature of the hierarchical
formation of spiral galaxies such as M31 and the Milky Way.


title: Macroengineering in the Galactic Context: A New Agenda for Astrobiology

abstract:
  We hereby consider the problem of detectability of macro-engineering projects
over interstellar distances, in the context of Search for ExtraTerrestrial
Intelligence (SETI). Freeman J. Dyson and his imaginative precursors, like
Konstantin Tsiolkovsky, Olaf Stapledon or John B. S. Haldane, suggested
macro-engineering projects as focal points in the context of extrapolations
about the future of humanity and, by analogy, other intelligent species in the
Milky Way. We emphasize that the search for signposts of extraterrestrial
macro-engineering projects is not an optional pursuit within the family of
ongoing and planned SETI projects; inter alia, the failure of the orthodox SETI
thus far clearly indicates this. Instead, this approach (for which we suggest a
name of "Dysonian") should be the front-line and mainstay of any cogent SETI
strategy in future, being significantly more promising than searches for
directed, intentional radio or microwave emissions. This is in accord with our
improved astrophysical understanding of the structure and evolution of the
Galactic Habitable Zone, as well as with the recent wake-up call of Steven J.
Dick to investigate consequences of postbiological evolution for astrobiology
in general and SETI programs in particular. The benefits this multidisciplinary
approach may bear for astrobiologists, evolutionary theorists and
macro-engineers are also briefly highlighted.


title:
The Unified Model of Active Galactic Nuclei: I. Non-hidden Broad Line
  Region Seyfert 2 and Narrow Line Seyfert 1 Galaxies

abstract:
  The unified model of Seyfert galaxies suggests that there are hidden
broad-line regions (HBLRs) in Seyfert 2 galaxies (S2s). However, there is
increasing evidence for the appearance of a subclass of S2s lacking of HBLR
(non-HBLR S2s). An interesting issue arises as to relations of non-HBLR S2s
with other types of Seyfert galaxies and whether or not they can be included in
the unified model. We assemble two sub-samples consisting of 42 non-HBLR S2s
and 44 narrow-line Seyfert 1s (NLS1s) with redshift $z\le 0.05$ from published
literatures to explore this issue. We compare black hole masses in the galactic
centers, accretion rates, infrared color ratio ($f_{60 \mu \rm m}/f_{25 \mu \rm
m}$) as a potential indicator of the dusty torus orientation, \oiii $\lambda
5007$, radio and far infrared luminosities. We find that non-HBLR S2s and NLS1s
have: 1) similar distributions of the black hole masses ($10^6-3\times
10^7\sunm$) and the Eddington ratios ($L_{\rm Bol}/L_{\rm Edd}\sim 1$); 2)
significantly different distributions of $f_{60 \mu \rm m}/f_{25 \mu \rm m}$
ratios; 3) similar distributions of bulge magnitudes and luminosities of [O
{\sc iii}], radio, far infrared emission. The similarities and differences can
be understood naturally if they are intrinsically same but non-HBLR S2s are
viewed at larger angles of observer's sight than NLS1s. We thus suggest that
non-HBLR S2s only have "narrower" broad line regions and they are the
counterparts of NLS1s viewed at high inclination angles. The absence of the
polarized emission line in non-HBLR S2s is caused by the less massive black
holes and high accretion rate similar to NLS1s. The implications of the
unification scheme of non-HBLR S2s and NLS1s are discussed.


title: The Hubble Sphere Hydrogen Survey

abstract:
  An all sky redshift survey, using hydrogen 21 cm emission to locate galaxies,
can be used to track the wavelength of baryon acoustic oscillations imprints
from z ~ 1.5 to z = 0. This will allow precise determination of the evolution
of dark energy. A telescope made of fixed parabolic cylindrical reflectors
offers substantial benefit for such a redshift survey. Fixed cylinders can be
built for low cost, and long cylinders also allow low cost fast fourier
transform techniques to be used to define thousands of simultaneous beams. A
survey made with fixed reflectors naturally covers all of the sky available
from it's site with good uniformity, minimizing sample variance in the
measurement of the acoustic peak wavelength. Such a survey will produce about a
billion redshifts, nearly a thousand times the number available today. The
survey will provide a three dimensional mapping of a substantial fraction of
the Hubble Sphere.


title:
High-Performance Small-Scale Simulation of Star Clusters Evolution on
  Cray XD1

abstract:
  In this paper, we describe the performance of an $N$-body simulation of star
cluster with 64k stars on a Cray XD1 system with 400 dual-core Opteron
processors. A number of astrophysical $N$-body simulations were reported in
SCxy conferences. All previous entries for Gordon-Bell prizes used at least
700k particles. The reason for this preference of large numbers of particles is
the parallel efficiency. It is very difficult to achieve high performance on
large parallel machines, if the number of particles is small. However, for many
scientifically important problems the calculation cost scales as $O(N^{3.3})$,
and it is very important to use large machines for relatively small number of
particles. We achieved 2.03 Tflops, or 57.7% of the theoretical peak
performance, using a direct $O(N^2)$ calculation with the individual timestep
algorithm, on 64k particles. The best efficiency previously reported on similar
calculation with 64K or smaller number of particles is 12% (9 Gflops) on Cray
T3E-600 with 128 processors. Our implementation is based on highly scalable
two-dimensional parallelization scheme, and low-latency communication network
of Cray XD1 turned out to be essential to achieve this level of performance.


title: Formation of Primordial Stars in a LCDM Universe

abstract:
  We study the formation of the first generation of stars in the standard cold
dark matter model, using a very high-resolution hydordynamic simulations. Our
simulation achieves a dynamic range of 10^{10} in length scale. With accurate
treatment of atomic and molecular physics, it allows us to study the
chemo-thermal evolution of primordial gas clouds to densities up to n =
10^{16}/cc without assuming any a priori equation of state; a six orders of
magnitudes improvement over previous three-dimensional calculations. All the
relevant atomic and molecular cooling and heating processes, including cooling
by collision-induced continuum emission, are implemented. For calculating
optically thick H2 cooling at high densities, we use the Sobolev method. To
examine possible gas fragmentation owing to thermal instability, we compute
explicitly the growth rate of isobaric perturbations. We show that the cloud
core does not fragment in either the low-density or high-density regimes. We
also show that the core remains stable against gravitational deformation and
fragmentation. We obtain an accurate gas mass accretion rate within a 10 Msun
innermost region around the protostar. The protostar is accreting the
surrounding hot gas at a rate of 0.001-0.01 Msun/yr. From these findings we
conclude that primordial stars formed in early minihalos are massive. We carry
out proto-stellar evolution calculations using the obtained accretion rate. The
resulting mass of the first star is M_ZAMS = 60-100 Msun, with the exact mass
dependent on the actual accretion rate.


title:
The Sub-parsec Scale Radio Properties of Southern Starburst Galaxies. I.
  Supernova Remnants, the Supernova Rate, and the Ionised Medium in the NGC 253
  Starburst

abstract:
  Wide-field, very long baseline interferometry (VLBI) observations of the
nearby starburst galaxy NGC 253, obtained with the Australian Long Baseline
Array (LBA), have produced a 2.3 GHz image with a maximum angular resolution of
15 mas (0.3 pc). Six sources were detected, all corresponding to sources
identified in higher frequency (>5 GHz) VLA images. One of the sources,
supernova remnant 5.48-43.3, is resolved into a shell-like structure
approximately 90 mas (1.7 pc) in diameter. From these data and data from the
literature, the spectra of 20 compact radio sources in NGC 253 were modelled
and found to be consistent with free-free absorbed power laws. Broadly, the
free-free opacity is highest toward the nucleus but varies significantly
throughout the nuclear region (tau_0 ~ 1->20), implying that the overall
structure of the ionised medium is clumpy. Of the 20 sources, nine have flat
intrinsic spectra associated with thermal radio emission and the remaining 11
have steep intrinsic spectra, associated with synchrotron emission from
supernova remnants. A supernova rate upper limit of 2.4 yr^-1 is determined for
the inner 320 pc region of the galaxy at the 95% confidence level, based on the
lack of detection of new sources in observations spanning almost 17 years and a
simple model for the evolution of supernova remnants. A supernova rate of >0.14
(v/10^4) yr^-1 is implied from estimates of supernova remnant source counts,
sizes and expansion rates, where v is the radial expansion velocity of the
supernova remnant in km s^-1. A star formation rate of 3.4 (v/10^4) <
SFR(M<=5Msun) < 59 Msun yr^-1 has been estimated directly from the supernova
rate limits and is of the same order of magnitude as rates determined from
integrated FIR and radio luminosities.


title: Detection of H2D+ in a massive prestellar core in Orion B

abstract:
  Aims. The purpose of this study is to examine the prediction that the
deuterated H3+ ion, H2D+, can be found exclusively in the coldest regions of
molecular cloud cores. This is also a feasibility study for the detection of
the ground-state line of ortho-H2D+ at 372 GHz with APEX.
  Methods. The 1(10)-1(11) transition of H2D+ at 372 GHz was searched towards
selected positions in the massive star forming cloud OriB9, in the dark cloud
L183, and in the low- to intermediate mass star-forming cloud R CrA.
  Results. The line was detected in cold, prestellar cores in the regions of
OriB9 and L183, but only upper limits were obtained towards other locations
which either have elevated temperatures or contain a newly born star. The H2D+
detection towards OriB9 is the first one in a massive star-forming region. The
fractional ortho-H2D+ abundances (relative to H2) are estimated to be about
1.0E-10 in two cold cores in OriB9, and 3.0E-10 in the cold core of L183.
  Conclusions. The H2D+ detection in OriB9 shows that also massive star forming
regions contain very cold prestellar cores which probably have reached matured
chemical composition characterized, e.g., by a high degree of deuterium
fractionation. Besides as a tracer of the interior parts of prestellar cores,
H2D+ may therefore be used to put contraints on the timescales related to
massive star formation.


title:
The role of Kelvin-Helmholtz instability in the internal structure of
  relativistic outflows. The case of the jet in 3C 273

abstract:
  Relativistic outflows represent one of the best-suited tools to probe the
physics of AGN. Numerical modelling of internal structure of the relativistic
outflows on parsec scales provides important clues about the conditions and
dynamics of the material in the immediate vicinity of the central black holes
in AGN. We investigate possible causes of the structural patterns and
regularities observed in the parsec-scale jet of the well-known quasar 3C 273.
We present here the results from a 3D relativistic hydrodynamics numerical
simulation based on the parameters given for the jet by Lobanov & Zensus
(2001), and one in which the effects of jet precession and the injection of
discrete components have been taken into account. We compare the model with the
structures observed in 3C 273 using very long baseline interferometry and
constrain the basic properties of the flow. We find growing perturbation modes
in the simulation with similar wavelengths to those observed, but with a
different set of wave speeds and mode identification. If the observed longest
helical structure is produced by the precession of the flow, longer precession
periods should be expected. Our results show that some of the observed
structures could be explained by growing Kelvin-Helmholtz instabilities in a
slow moving region of the jet. However, we point towards possible errors in the
mode identification that show the need of more complete linear analysis in
order to interpret the observations. We conclude that, with the given viewing
angle, superluminal components and jet precession cannot explain the observed
structures.


title: A Panoramic Mid-infrared Survey of Two Distant Clusters

abstract:
  (abridged) We present panoramic Spitzer MIPS 24um observations covering
9x9Mpc (25'x25') fields around two massive clusters, Cl0024+16 and MS0451-03,
at z=0.39 and z=0.55. Our observations cover a very wide range of environments
within these clusters, from high-density regions around the cores out to the
turn-around radius. Cross-correlating the mid-infrared catalogs with deep
optical and near-infrared imaging of these fields, we investigate the
optical/near-infrared colors of the mid-infrared sources. We find excesses of
mid-infrared sources with optical/near-infrared colors expected of cluster
members in the two clusters and test this selection using spectroscopically
confirmed 24um members. The much more significant excess is associated with
Cl0024+16, whereas MS0451-03 has comparatively few mid-infrared sources. The
mid-infrared galaxy population in Cl0024+16 appears to be associated with dusty
star-forming galaxies (typically redder than the general cluster population by
up to A_V~1-2 mags) rather than emission from dusty tori around active galactic
nuclei (AGN) in early-type hosts. The inferred total-infrared star-formation
rates in Cl0024+16 are typically >5x greater than those found from a similar
Halpha survey, indicating significant obscured activity in the cluster
population. We find evidence for strong evolution of the level of dust-obscured
star-formation in dense environments out to z=0.5, analogous to the rise in
fraction of optically-selected star-forming galaxies seen in clusters and the
field out to similar redshifts. However, there are clearly significant
cluster-to-cluster variations in the populations of mid-infrared sources,
probably reflecting differences in the intracluster media and recent dynamical
evolution of these systems.


title:
Time Dependent Monte Carlo Radiative Transfer Calculations For
  3-Dimensional Supernova Spectra, Lightcurves, and Polarization

abstract:
  We discuss Monte-Carlo techniques for addressing the 3-dimensional
time-dependent radiative transfer problem in rapidly expanding supernova
atmospheres. The transfer code SEDONA has been developed to calculate the
lightcurves, spectra, and polarization of aspherical supernova models. From the
onset of free-expansion in the supernova ejecta, SEDONA solves the radiative
transfer problem self-consistently, including a detailed treatment of gamma-ray
transfer from radioactive decay and with a radiative equilibrium solution of
the temperature structure. Line fluorescence processes can also be treated
directly. No free parameters need be adjusted in the radiative transfer
calculation, providing a direct link between multi-dimensional hydrodynamical
explosion models and observations. We describe the computational techniques
applied in SEDONA, and verify the code by comparison to existing calculations.
We find that convergence of the Monte Carlo method is rapid and stable even for
complicated multi-dimensional configurations. We also investigate the accuracy
of a few commonly applied approximations in supernova transfer, namely the
stationarity approximation and the two-level atom expansion opacity formalism.


title:
On the self-enrichment scenario of galactic globular clusters:
  Constraints on the IMF

abstract:
  Galactic globular cluster (GC) stars exhibit abundance patterns which are not
shared by their field counterparts, In the framework of the widely accepted
"self-enrichment" scenario for GCs, we present a new method to derive the
Initial Mass Function (IMF) of the polluter stars, by using the observed O/Na
abundance distribution. We focus on NGC 2808, a GC for which the largest sample
of O and Na abundance determinations is presently available. We consider two
classes of possible "culprits" : massive Asymptotic Giant Branch (AGB) stars
(4-9 Msun) and winds of massive stars (WMS) in the mass range 10-100 Msun. We
obtain upper limits for the slope of the IMF (assumed to be given by a
power-law) of the stars initially more massive than the present turnoff mass.
We also derive lower limits for the amount of stellar residues. We find that
the polluter IMF had to be much flatter than presently observed IMFs in stellar
clusters, in agreement with the results of two other methods for GC IMF
determination. Additionaly, we find that the present mass of the GC should be
totally dominated by stellar remnants if the polluters were AGB stars, but not
so in the case of WMS. We critically analyse the advantages and shortcomings of
each potential polluter class, and we find the WMS scenario more attractive.


title:
Imaging extended sources with coded mask telescopes: Application to the
  INTEGRAL IBIS/ISGRI instrument

abstract:
  Context. In coded mask techniques, reconstructed sky images are
pseudo-images: they are maps of the correlation between the image recorded on a
detector and an array derived from the coded mask pattern. Aims. The
INTEGRAL/IBIS telescope provides images where the flux of each detected source
is given by the height of the local peak in the correlation map. As such, it
cannot provide an estimate of the flux of an extended source. What is needed is
intensity sky images giving the flux per solide angle as typically done at
other wavelengths. Methods. In this paper, we present the response of the
INTEGRAL IBIS/ISGRI coded mask instrument to extended sources. We develop a
general method based on analytical calculations in order to measure the
intensity and the associated error of any celestial source and validated with
Monte-Carlo simulations. Results. We find that the sensitivity degrades almost
linearly with the source extent. Analytical formulae are given as well as an
easy-to-use recipe for the INTEGRAL user. We check this method on IBIS/ISGRI
data but these results are general and applicable to any coded mask telescope.


title: Coma revealed as an extended hard X-rays source by INTEGRAL IBIS/ISGRI

abstract:
  Aims. We report the INTEGRAL/IBIS observations of the Coma Cluster in the
hard X-ray/soft-ray domain. Methods. Since the Coma Cluster appears as an
extended source, its global intensity and significance cannot be directly
extracted with standard coded mask analysis. We used the method of imaging the
extended sources with a coded mask telescope developed by Renaud et al. (2006).
Results. The imaging capabilities and the sensitivity of the IBIS/ISGRI coded
mask instrument allows us to identify for the first time the site of the
emission above ~ 15 keV. We have studied the Coma Cluster morphology in the
18-30keV band and found that it follows the prediction based on X-ray
observations.We also bring constraints on the non-thermal mechanism
contribution at higher energies.


title: Detailed XMM-Newton Observation of the Cluster of Galaxies Abell 1060

abstract:
  We present results from the XMM-Newton observation of the non-cooling flow
cluster A1060. Large effective area of XMM-Newton enables us to investigate the
nature of this cluster in unprecedented detail. From the observed surface
brightness distribution, we have found that the gravitational mass distribution
is well described by the NFW profile but with a central density slope of ~1.5.
We have undoubtedly detected a radial temperature decrease of as large as ~30%
from the center to the outer region (r ~13'), which seems much larger than that
expected from the temperature profile averaged over nearby clusters. We have
established that the temperature of the region ~7' southeast of the center is
higher than the azimuthally averaged temperature of the same radius by ~20%.
Since the pressure of this region already reaches equilibrium with the
environment, the temperature structure can be interpreted as having been
produced between 4*10^7 yr (the sound-crossing time) and 3*10^8 yr (the thermal
conduction time) ago. We have found that the high-metallicity blob located at
\~1.'5 northeast of NGC 3311 is more extended and its iron mass of 1.9*10^7
M_solar is larger by an order of magnitude than estimated from our Chandra
observation. The amount of iron can still be considered as being injected
solely from the elliptical galaxy NGC3311.


title:
The discovery of a significant sample of massive galaxies at redshifts 5
  < z < 6 in the UKIDSS Ultra Deep Survey Early Data Release

abstract:
  We have exploited the large area coverage of the combined UKIDSS Ultra Deep
Survey (UDS) and Subaru/XMM-Newton Deep Survey (SXDS) to search for bright
Lyman-break galaxies (LBGs) at z >= 5. Using the available
optical+near-infrared photometry to efficiently exclude low-redshift
contaminants, we identify nine z >= 5 LBG candidates brighter than z'=25(AB)
within the 0.6 square degree overlap region between the UDS early data release
(EDR) and the optical coverage of the SXDS. Accounting for selection
incompleteness, we estimate the corresponding surface density of z >= 5 LBGs
with z'<=25(AB) to be 0.005+/-0.002 per square arcmin. Modelling of the
optical+near-infrared photometry constrains the candidates' redshifts to lie in
the range 5.1 < z < 5.9, and provides estimates for their stellar masses.
Although the stellar mass estimates are individually uncertain, a stacking
analysis suggests that the typical stellar mass of the LBG candidates is
>~5x10^10 Msun which, if confirmed, places them amongst the most massive
galaxies currently known at z >= 5. It is found that Lambda CDM structure
formation can produce sufficient numbers of dark matter halos at z >= 5 to
accommodate our estimated number density of massive LBGs for plausible values
of sigma_8 and the ratio of stellar to dark matter. Moreover, it is found that
recent galaxy formation models can also account for the existence of such
massive galaxies at z >= 5. Finally, no evidence is found for the existence of
LBGs with stellar masses in excess of ~3x10^11 Msun at this epoch, despite the
large co-moving volume surveyed.


title:
Constraints on the mass of a habitable planet with water of nebular
  origin

abstract:
  From an astrobiological point of view, special attention has been paid to the
probability of habitable planets in extrasolar systems. The purpose of this
study is to constrain a possible range of the mass of a terrestrial planet that
can get water. We focus on the process of water production through oxidation of
the atmospheric hydrogen--the nebular gas having been attracted
gravitationally--by oxide available at the planetary surface. For the water
production to work well on a planet, a sufficient amount of hydrogen and enough
high temperature to melt the planetary surface are needed. We have simulated
the structure of the atmosphere that connects with the protoplanetary nebula
for wide ranges of heat flux, opacity, and density of the nebular gas. We have
found both requirements are fulfilled for an Earth-mass planet for wide ranges
of the parameters. We have also found the surface temperature of planets of <=
0.3 Earth masses is lower than the melting temperature of silicate (~ 1500K).
On the other hand, a planet of more than several Earth masses becomes a gas
giant planet through runaway accretion of the nebular gas.


title:
C18O (3-2) observations of the Cometary Globule CG 12: a cold core and a
  C18O hot spot

abstract:
  The feasibility of observing the C18O (3-2) spectral line in cold clouds with
the APEX telescope has been tested. As the line at 329.330 GHz lies in the wing
of a strong atmospheric H2O absorption it can be observed only at high altitude
observatories. Using the three lowest rotational levels instead of only two
helps to narrow down the physical properties of dark clouds and globules. The
centres of two C18O maxima in the high latitude low mass star forming region CG
12 were mapped in C18O (3-2) and the data were analyzed together with spectral
line data from the SEST. The T_MB(3-2)/T_MB(2-1) ratio in the northern C18O
maximum, CG 12 N, is 0.8, and in the southern maximum, CG 12 S, ~2. CG 12 N is
modelled as a 120'' diameter (0.4pc) cold core with a mass of 27 Msun. A small
size maximum with a narrow, 0.8 kms-1, C18O (3-2) spectral line with a peak
temperature of T_MB ~11 K was detected in CG 12 S. This maximum is modelled as
a 60'' to 80'' diameter (~0.2pc) hot (80 K < Tex < 200 K) ~1.6 Msun clump. The
source lies on the axis of a highly collimated bipolar molecular outflow near
its driving source. This is the first detection of such a compact, warm object
in a low mass star forming region.


title: Optical Polarimetry of the Jets of Nearby Radio Galaxies: I. The Data

abstract:
  We present an overview of new HST imaging polarimetry of six nearby radio
galaxies with optical jets. These observations triple the number of
extragalactic jets with subarcsecond-resolution optical polarimetry. We discuss
the polarization characteristics and optical morphology of each jet. We find
evidence of high optical polarization, averaging 20%, but reaching upwards of
$\sim 50%$ in some objects, confirming that the optical emission is
synchrotron, and that the components of the magnetic fields perpendicular to
the line of sight are well ordered. We find a wide range of polarization
morphologies, with each jet having a somewhat different relationship between
total intensity and polarized flux and the polarization position angle. We find
two trends in all of these jets. First, jet ``edges'' are very often associated
with high fractional optical polarizations, as also found in earlier radio
observations of these and other radio jets. In these regions, the magnetic
field vectors appear to track the jet direction, even at bends, where we see
particularly high fractional polarizations. This indicates a strong link
between the local magnetic field and jet dynamics. Second, optical flux maximum
regions are usually well separated from maxima in fractional polarization and
often are associated with polarization minima. This trend is not found in radio
data and was found in our optical polarimetry of M87 with HST. However, unlike
in M87, we do not find a general trend for near-90$^\circ$ rotations in the
optical polarization vectors near flux maxima. We discuss possibilities for
interpreting these trends, as well as implications for jet dynamics, magnetic
field structure and particle acceleration.


title:
Magnetars versus Radio Pulsars: MHD Stability in Newborn Highly
  Magnetized Neutron Stars

abstract:
  We study the stability/establishment of dipolar magnetostatic equilibrium
configurations in new--born neutron stars (NSs) in dependence on the rotational
velocity $\Omega$ and on the initial angle $\alpha$ between rotation and
magnetic axis. The NS is modeled as a sphere of a highly magnetized ($B \sim
10^{15}$G) incompressible fluid of uniform density which rotates rigidly. For
the initial dipolar background magnetic field, which defines the magnetic axis,
two different configurations are assumed. We solve the 3D non--linear MHD
equations by use of a spectral code. The problem in dimensionless form is
completely defined by the initial field strength (for a fixed field geometry),
the magnetic Prandtl number $\Pm$, and the normalized rotation rate. The
evolution of the magnetic and velocity fields is considered for initial
magnetic field strengths characterized by the ratio of ohmic diffusion and
initial \Alf{} travel times $\ttOhm/\ttAO \approx 1000$, for $\Pm = 0.1, 1,
10$, and the ratio of rotation period and initial \Alf{} travel time, $P/\ttAO
= 0.012, 0.12, 1.2, 12$. We find hints for the existence of a unique stable
dipolar magnetostatic configuration for any specific $\alpha$, independent of
the initial field geometry. Comparing NSs possessing the same field structure
at the end of their proto--NS phase, it turns out that sufficiently fast
rotating NSs ($P\la6 $ms) with $\alpha \la 45^0$ retain their magnetar field,
while the others lose almost all of their initial magnetic energy by
transferring it into magnetic and kinetic energy of relatively small--scaled
fields and continue their life as radio pulsars with a dipolar surface field of
$10^{12...13}$G.


title: Exploring The Frequency Of Close-In Jovian Planets Around M Dwarfs

abstract:
  We discuss our high precision radial velocity results of a sample of 90 M
dwarfs observed with the Hobby-Eberly Telescope and the Harlan J. Smith 2.7 m
Telescope at McDonald Observatory, as well as the ESO VLT and the Keck I
telescopes, within the context of the overall frequency of Jupiter-mass
planetary companions to main sequence stars. None of the stars in our sample
show variability indicative of a giant planet in a short period orbit, with a <
1 AU. We estimate an upper limit of the frequency f of close-in Jovian planets
around M dwarfs as < 1.27% (at the 1 sigma confidence level). Furthermore, we
determine the efficiency of our survey to have noticed planets in circular
orbits as 98% for companions with m sin i > 3.8 M_Jup and a < 0.7 AU. For
eccentric orbits (e=0.6) the survey completeness is 95% for all planets with m
sin i > 3.5 M_Jup and a < 0.7 AU. Our results point toward a generally lower
frequency of close-in Jovian planets for M dwarfs as compared to FGK-type
stars. This is an important piece of information for our understanding of the
process of planet formation as a function of stellar mass.


title: PTD vs. PO effects in power and polarisation of PLANCK HFI 100 beams

abstract:
  A method of accelerated computation of broadband far off boresight patterns
of telescope beams is extended and applied to the 100 GHz channels of Planck
HFI (HFI 100). Far off boresight angle power patterns are computed with both
GRASP PTD and NUIM PO software, considering cuts with an angular size of 10
degrees. The former reveal secondary oscillations of radial power distribution
as compared with the latter. The difference for power patterns of a/b
polarisation channels is also investigated.


title:
Analysis of Saturn main rings by continuous wavelet transform with the
  complex Morlet wavelet

abstract:
  A new method based on continuous wavelet transform with the complex Morlet
wavelet to analyze Saturn main rings is presented. It allows to investigate in
detail the resonance zones and reveal the coexistence of waves with stable
periods and the wave trains with a variable instant period. This method is
based on the replacing the integration of the fast--oscillation function by the
solution of the partial differential equations. It is shown that such an
approach is an effective tool for the study the radial structure of Saturn's A,
B, and C rings. All the analyzed images were obtained from the Cassini
spacecraft during 2004--2005 years.


title: Inhomogeneous Cosmology, Inflation and Late-Time Accelerating Universe

abstract:
  An exact inhomogeneous solution of Einstein's field equations is shown to be
able to inflate in a non-uniform way in the early universe and explain
anomalies in the WMAP power spectrum data. It is also possible for the model to
explain the accelerated expansion of the universe by late-time inhomogeneous
structure.


title: Helical Magnetorotational Instability in Magnetized Taylor-Couette Flow

abstract:
  Hollerbach and Rudiger have reported a new type of magnetorotational
instability (MRI) in magnetized Taylor-Couette flow in the presence of combined
axial and azimuthal magnetic fields. The salient advantage of this "helical''
MRI (HMRI) is that marginal instability occurs at arbitrarily low magnetic
Reynolds and Lundquist numbers, suggesting that HMRI might be easier to realize
than standard MRI (axial field only). We confirm their results, calculate HMRI
growth rates, and show that in the resistive limit, HMRI is a weakly
destabilized inertial oscillation propagating in a unique direction along the
axis. But we report other features of HMRI that make it less attractive for
experiments and for resistive astrophysical disks. Growth rates are small and
require large axial currents. More fundamentally, instability of highly
resistive flow is peculiar to infinitely long or periodic cylinders: finite
cylinders with insulating endcaps are shown to be stable in this limit. Also,
keplerian rotation profiles are stable in the resistive limit regardless of
axial boundary conditions. Nevertheless, the addition of toroidal field lowers
thresholds for instability even in finite cylinders.


title:
Search for Diffuse Astrophysical Neutrino Flux Using Ultra-High-Energy
  Upward-Going Muons in Super-Kamiokande I

abstract:
  Many astrophysical models predict a diffuse flux of high-energy neutrinos
from active galactic nuclei and other extra-galactic sources. At muon energies
above 1 TeV, the upward-going muon flux induced by neutrinos from active
galactic nuclei is expected to exceed the flux due to atmospheric neutrinos. We
have performed a search for this astrophysical neutrino flux by looking for
upward-going muons in the highest energy data sample from the Super-Kamiokande
detector using 1679.6 live days of data. We found one extremely high energy
upward-going muon event, compared with an expected atmospheric neutrino
background of 0.46 plus or minus 0.23 events. Using this result, we set an
upper limit on the diffuse flux of upward-going muons due to neutrinos from
astrophysical sources in the muon energy range 3.16-100 TeV.


title:
Testing the Disk Regulation Paradigm with Spitzer Observations. I.
  Rotation Periods of Pre-main Sequence Stars in the IC 348 Cluster

abstract:
  We present 75 new stellar rotation periods in the young cluster IC348. Stars
estimated to be less massive than 0.25 Mo show a unimodal distribution with a
peak at P ~1-2 d) and a tail of slower rotators, while stars estimated to be
more massive than 0.2 Mo show a bimodal distribution with peaks at ~2 and ~8 d.
We combine all published rotation periods in IC348 with Spitzer/IRAC photometry
in order to test the disk-braking paradigm. We find no evidence that the tail
of slow rotators in low-mass stars or the long period peak in high-mass stars
are preferentially populated by objects with disks as might be expected based
on the current disk-braking model. Also, we find no significant correlation
between period and the magnitude of the IR-excess, regardless of the mass range
considered. Our results do not support a strong correlation in this cluster
between rotation period and the presence of a disk as predicted by disk-braking
theory. Rather, they are consistent with the suggestion that the correlation
between period and the amplitude of the (I-K) excess reported in the past is a
secondary manifestation of the correlation between the amplitude of near-IR
excess and mass. Finally, we find some indication that the disk fraction
decreases significantly for stars with very short periods (P < 1.5 d). This is
the only feature of our sample that could potentially be interpreted as
evidence for disk braking. It has been proposed that the observational
signatures of disk braking might be significantly masked by the intrinsic
breadth of the initial period distribution. We argue that more rigorous
modeling of angular momentum evolution and a quantitative analysis of the
observational data are required before the disk-braking model can be regarded
as inconsistent with observations.


title:
Discrete Self-Similarity Of RR Lyrae Stars II. Period Spectrum For A
  Very Large Sample

abstract:
  A recent paper demonstrated a considerable degree of self-similarity between
RR Lyrae stars and their atomic scale analogues: excited helium atoms
undergoing single-level transition between n = 7 and n = 10. Discrete
self-similarity between these fractal analogues was indentified in terms of
their masses, radii, oscillation periods, basic morphologies and kinematics. In
this second paper on the subject, an extremely large and carefully analyzed
sample of RR Lyrae oscillation periods provides further evidence for a unique
match between the predicted set of discrete periods, based exclusively on the
known helium spectrum and the discrete scaling equations of a fractal
cosmological paradigm, and the observed period spectra of RR Lyrae stars.


title:
Thermal Infrared Constraint to a Planetary Companion of Vega with the
  MMT Adaptive Optics System

abstract:
  Vega may have a massive companion in a wide orbit, as evidenced by structure
in its cold dust debris. We have tested this hypothesis by direct imaging with
adaptive optics in the M band. The observations were made with a newly
commissioned thermal infrared camera, Clio, on the 6.5 MMT AO system with
low-background deformable secondary. The observations constrain a planet to be
less than 7 M$_J$ at the approximate position angle expected from the dust
structure and at a radius $>$ 20AU (2.5 arcsec) . This result is more stringent
than similar previous near-infrared observations of Vega, that achieve limits
of 20 and 10 M$_J$ at separations of 7 arcsec. The higher sensitivity is due
both to the more favorable contrast of gas giant planets at M band and to the
higher Strehl and more stable point spread function at longer wavelengths.
Future L' or M band observations could provide a powerful approach for wide
separation planet detection, especially for cooler, and thus older or less
massive planets. The natural best targets are nearby stars where planets in the
range of 5-15 M$_J$ and as old as several Gyr are expected to be detectable
with this technique.


title:
Revealing the Dark TeV Sky: The Atmospheric Cherenkov Imaging Technique
  for Very High Energy Gamma-ray Astronomy

abstract:
  The Atmospheric Cherenkov Imaging Technique has opened up the gamma-ray
spectrum from 100 GeV to 50 TeV to astrophysical exploration. The development
of the technique (with emphasis on the early days) is described as are the
basic principles underlying its application to gamma-ray astronomy. The current
generation of arrays of telescopes, in particular, VERITAS is briefly
described.


title: Clio: a 3-5 micron AO planet-finding camera

abstract:
  Clio is an adaptive-optics camera mounted on the 6.5 meter MMT optimized for
diffraction-limited L' and M-band imaging over a ~15'' field. The instrument
was designed from the ground up with a large well-depth, fast readout thermal
infrared (~3-5 micron) 320 by 256 pixel InSb detector, cooled optics, and
associated focal plane and pupil masks (with the option for a coronograph) to
minimize the thermal background and maximize throughput. When coupled with the
MMT's adaptive secondary AO (two warm reflections) system's low thermal
background, this instrument is in a unique position to image nearby warm
planets, which are the brightest in the L' and M-band atmospheric windows. We
present the current status of this recently commissioned instrument that
performed exceptionally during first light. Our instrument sensitivities are
impressive and are sky background limited: for an hour of integration, we
obtain an L'-band 5 sigma detection limit of of 17.0 magnitudes (Strehl ~80%)
and an M-band limit of 14.5 (Strehl ~90%). Our M-band sensitivity is lower due
to the increase in thermal sky background. These sensitivities translate to
finding relatively young planets five times Jupiter mass at 10 pc within a few
AU of a star. Presently, a large Clio survey of nearby stellar systems is
underway including a search for planets around solar-type stars, M dwarfs, and
white dwarfs. Even with a null result, we can place strong constraints on
planet distribution models.


title: Massive-Star Supernovae as Major Dust Factories

abstract:
  We present late-time optical and mid-infrared observations of the Type-II
supernova 2003gd in NGC 628. Mid-infrared excesses consistent with cooling dust
in the ejecta are observed 499-678 days after outburst, and are accompanied by
increasing optical extinction and growing asymmetries in the emission-line
profiles. Radiative-transfer models show that up to 0.02 solar masses of dust
has formed within the ejecta, beginning as early as 250 days after outburst.
These observations show that dust formation in supernova ejecta can be
efficient and that massive-star supernovae can be major dust producers
throughout the history of the Universe.


title: Lower Limit to the Scale of an Effective Theory of Gravitation

abstract:
  We consider a linearized, effective quantum theory of gravitation in which
gravity weakens at energies higher than ~10^-3 eV in order to accommodate the
apparent smallness of the cosmological constant. Such a theory predicts
departures from the static Newtonian inverse-square force law on distances
below ~0.05 mm. However, we show that such a modification also leads to changes
in the long-range behavior of gravity and is inconsistent with observed
gravitational lenses.


title:
Constraining the population of 6 < z < 10 star-forming galaxies with
  deep near-IR images of lensing clusters

abstract:
  (abridged) We present the first results of our deep survey of lensing
clusters aimed at constraining the abundance of star-forming galaxies at
z~6-10. Deep near-IR photometry of two lensing clusters (A1835 and AC114) was
obtained with ISAAC/VLT. These images, combined with existing data in the
optical bands, including HST images, were used to select very high redshift
candidates at z>~6 among the optical-dropouts. We have identified 18(8) first
and second-category optical dropouts in A1835 (AC114), detected in more than
one filter up to H(Vega)~23.8 (AB~25.2,uncorrected for lensing). Among them,
8(5) exhibit homogeneous SEDs compatible with star-forming galaxies at z>~6,
and 5(1) are more likely intermediate-redshift EROs based on luminosity
considerations. We have also identified a number of fainter sources in these
fields fulfilling our photometric selection and located around the critical
lines. We use all these data to make a first attempt at constraining the
density of star-forming galaxies present at 6<z<10 using lensing clusters.
Taken at face value, it appears that the number of candidates found seems to be
higher than the one achieved in blank fields with similar photometric depth in
the near-IR. The luminosity function derived for z>6 candidates appears
compatible with that of LBGs at z~3. The turnover observed by Bouwens et al.
(2005) towards the bright end relative to the z~3 LF is not observed in this
sample. Also the upper limit for the UV SFR density at z~6-10 is compatible
with the usual values derived at z~5-6, but higher than the estimates obtained
in the NICMOS Ultra Deep Field (UDF). Increasing the number of blank and
lensing fields with ultra-deep near-IR photometry is essential to get more
accurate constraints on the abundance of z>6 galaxies.


title: Mapping the ZZ Ceti Instability Strip: Discovery of 6 New Pulsators

abstract:
  As part of an ongoing program to map better the empirical instability strip
of pulsating ZZ Ceti white dwarfs, we present a brief progress report based on
our last observing season. We discuss here high-speed photometric measurements
for 6 new pulsators. These stars were selected on the basis of preliminary
measurements of their effective temperature and surface gravity that placed
them inside or near the known ZZ Ceti instability strip. We also report
detection limits for a number of DA white dwarfs that showed no sign of
variability. Finally, we revisit the ZZ Ceti star G232-38 for which we obtained
improved high-speed photometry.


title: Astrometry and Photometry with Coronagraphs

abstract:
  We propose a solution to the problem of astrometric and photometric
calibration of coronagraphic images with a simple optical device which, in
theory, is easy to use. Our design uses the Fraunhofer approximation of Fourier
optics. Placing a periodic grid of wires (we use a square grid) with known
width and spacing in a pupil plane in front of the occulting coronagraphic
focal plane mask produces fiducial images of the obscured star at known
locations relative to the star. We also derive the intensity of these fiducial
images in the coronagraphic image. These calibrator images can be used for
precise relative astrometry, to establish companionship of other objects in the
field of view through measurement of common proper motion or common parallax,
to determine orbits, and to observe disk structure around the star
quantitatively. The calibrator spots also have known brightness, selectable by
the coronagraph designer, permitting accurate relative photometry in the
coronagraphic image. This technique, which enables precision exoplanetary
science, is relevant to future coronagraphic instruments, and is particularly
useful for `extreme' adaptive optics and space-based coronagraphy.


title: Performance of AAOmega: the AAT multi-purpose fibre-fed spectrograph

abstract:
  AAOmega is the new spectrograph for the 2dF fibre-positioning system on the
Anglo-Australian Telescope. It is a bench-mounted, double-beamed design, using
volume phase holographic (VPH) gratings and articulating cameras. It is fed by
392 fibres from either of the two 2dF field plates, or by the 512 fibre SPIRAL
integral field unit (IFU) at Cassegrain focus. Wavelength coverage is 370 to
950nm and spectral resolution 1,000-8,000 in multi-Object mode, or 1,500-10,000
in IFU mode. Multi-object mode was commissioned in January 2006 and the IFU
system will be commissioned in June 2006.
  The spectrograph is located off the telescope in a thermally isolated room
and the 2dF fibres have been replaced by new 38m broadband fibres. Despite the
increased fibre length, we have achieved a large increase in throughput by use
of VPH gratings, more efficient coatings and new detectors - amounting to a
factor of at least 2 in the red. The number of spectral resolution elements and
the maximum resolution are both more than doubled, and the stability is an
order of magnitude better.
  The spectrograph comprises: an f/3.15 Schmidt collimator, incorporating a
dichroic beam-splitter; interchangeable VPH gratings; and articulating red and
blue f/1.3 Schmidt cameras. Pupil size is 190mm, determined by the competing
demands of cost, obstruction losses, and maximum resolution. A full suite of
VPH gratings has been provided to cover resolutions 1,000 to 7,500, and up to
10,000 at particular wavelengths.


title:
First results from SAPAC: towards a 3D-picture of the Fornax cluster
  core

abstract:
  A sophisticated SBF analysis package has been developed, designed to measure
distances of early-type galaxies by means of surface brightness fluctuations of
unresolved stars. This suite of programs called SAPAC is made readily available
to the astronomical community for extensive testing with the long-term goal to
provide the necessary tools for systematic distance surveys of early-type
galaxies using modern optical/NIR telescopes equipped with wide-field cameras.
We discuss the technical and scientific concepts of SAPAC and demonstrate its
capabilities by analysing deep B and R-band CCD images of 10 dwarf elliptical
(dE) galaxy candidates in the Fornax cluster obtained with FORS1 at the VLT.
All candidates are confirmed as cluster members. We then turn our attention to
the innermost region of the Fornax cluster. A total of 29 early-type galaxies
closer than three cluster core radii (2 degrees) from the central galaxy
NGC1399 have radial velocities and SBF distances. Their Hubble diagram exhibits
a pronounced S-shaped infall pattern suggesting a picture that Fornax is still
in the process of formation during the present epoch through a general collapse
and possible accretion of distinct groups of galaxies. The associated collapse
time is 2.9(+1.6, -0.9)Gyr. After cleansing our galaxy sample from a few
kinematical outliers the true distance of the Fornax cluster core is determined
at 20.13+-0.40 Mpc [(m-M)_0=31.51+-0.04mag]. Applying a bootstrap resampling
technique on the distance distribution with individual distance errors taken
into account further reveals a small intrinsic cluster depth of
sigma_int=0.74(+0.52,-0.74)Mpc in best agreement with the cluster's linear
extension in the sky: sigma_R.A=sigma_DEC~=0.5Mpc. (Abridged)


title:
The Deep Chandra Survey of the Groth Strip - II. optical identification
  of the X-ray sources

abstract:
  We discuss the optical and X-ray spectral properties of the sources detected
in a single 200ks Chandra pointing in the Groth-Westphal Strip region. Optical
identifications and spectroscopic redshifts are primarily from the DEEP2
survey. This is complemented with deeper (r~26mag) multi-waveband data (ugriz)
from the Canada France Hawaii Legacy Survey to estimate photometric redshifts
and to optically identify sources fainter than the DEEP2 magnitude limit
(R(AB)~24.5mag). We focus our study on the 2-10keV selected sample comprising
97 sources to the limit ~8e-16erg/s/cm2, this being the most complete in terms
of optical identification rate (86%) and redshift determination fraction (63%;
both spectroscopic and photometric). We first construct the redshift
distribution of the sample which shows a peak at z~1. This is in broad
agreement with models where less luminous AGNs evolve out to z~1 with powerful
QSOs peaking at higher redshift, z~2. Evolution similar to that of broad-line
QSOs applied to the entire AGN population (both type-I and II) does not fit the
data. We also explore the observed N_H distribution of the sample and estimate
a fraction of obscured AGN (N_H>1e22) of ~48%. This is found to be consistent
with both a luminosity dependent intrinsic N_H distribution, where less
luminous systems comprise a higher fraction of type-II AGNs, and models with a
fixed ratio 2:1 between type-I and II AGNs. We further compare our results with
those obtained in deeper and shallower surveys. We argue that a luminosity
dependent parametrisation of the intrinsic N_H distribution is required to
account for the fraction of obscured AGN observed in different samples over a
wide range of fluxes.


title: Effects of a Supermassive Black Hole Binary on a Nuclear Gas Disk

abstract:
  We study influence of a galactic central supermassive black hole (SMBH)
binary on gas dynamics and star formation activity in a nuclear gas disk by
making three-dimensional Tree+SPH simulations. Due to orbital motions of SMBHs,
there are various resonances between gas motion and the SMBH binary motion. We
have shown that these resonances create some characteristic structures of gas
in the nuclear gas disk, for examples, gas elongated or filament structures,
formation of gaseous spiral arms, and small gas disks around SMBHs. In these
gaseous dense regions, active star formations are induced. As the result, many
star burst regions are formed in the nuclear region.


title:
Self-consistent computation of gamma-ray spectra due to proton-proton
  interactions in black hole systems

abstract:
  In the inner regions of an accretion disk around a black hole, relativistic
protons can interact with ambient matter to produce electrons, positrons and
$\gamma$-rays. The resultant steady state electron and positron particle
distributions are self-consistently computed taking into account Coulomb and
Compton cooling, $e^-e^+$ pair production (due to $\gamma-\gamma$ annihilation)
and pair annihilation. While earlier works used the diffusion approximation to
obtain the particle distributions, here we solve a more general
integro-differential equation that correctly takes into account the large
change in particle energy that occur when the leptons Compton scatter off hard
X-rays. Thus this formalism can also be applied to the hard state of black hole
systems, where the dominant ambient photons are hard X-rays. The corresponding
photon energy spectrum is calculated and compared with broadband data of black
hole binaries in different spectral states. The results indicate that the
$\gamma$-ray spectra ($E > 0.8$ MeV) of both the soft and hard spectral states
and the entire hard X-ray/$\gamma$-ray spectrum of the ultra-soft state, could
be due to $p-p$ interactions. These results are consistent with the hypothesis
that there always exists in these systems a $\gamma$-ray spectral component due
to $p-p$ interactions which can contribute between 0.5 to 10% of the total
bolometric luminosty. The model predicts that {\it GLAST} would be able to
detect black hole binaries and provide evidence for the presence of non-thermal
protons which in turn would give insight into the energy dissipation process
and jet formation in these systems.


title:
Imaging Across the Spectrum: Synergies Between SKA and Other Future
  Telescopes

abstract:
  The Square Kilometer Array will be operating at the same time with several
new large optical, X-ray and Gamma-ray facilities currently under construction
or planned. Fostering synergies in astrophysical research made across different
spectral bands presents a compelling argument for designing the SKA such that
it would offer imaging capabilities similar to those of other future
telescopes. Imaging capabilities of the SKA are compared here with those of the
major future astrophysical facilities.


title: Active Galactic Nuclei at the Crossroads of Astrophysics

abstract:
  Over the last five decades, AGN studies have produced a number of spectacular
examples of synergies and multifaceted approaches in astrophysics. The field of
AGN research now spans the entire spectral range and covers more than twelve
orders of magnitude in the spatial and temporal domains. The next generation of
astrophysical facilities will open up new possibilities for AGN studies,
especially in the areas of high-resolution and high-fidelity imaging and
spectroscopy of nuclear regions in the X-ray, optical, and radio bands. These
studies will address in detail a number of critical issues in AGN research such
as processes in the immediate vicinity of supermassive black holes, physical
conditions of broad-line and narrow-line regions, formation and evolution of
accretion disks and relativistic outflows, and the connection between nuclear
activity and galaxy evolution.


title: 2-Dimensional Kinematics of Simulated Disc Merger Remnants

abstract:
  We present a two-dimensional kinematic analysis for a sample of simulated
binary disc merger remnants with mass ratios 1:1 and 3:1. For the progenitor
discs we used pure stellar models as well as models with 10% of their mass in
gas. A multitude of phenomena also observed in real galaxies are found in the
simulations. These include misaligned rotation, embedded discs, gas rings,
counter-rotating cores and kinematic misaligned discs. Using the 2D maps we
illustrate projection effects and the change in properties of a merger remnant
when gas is included in the merger. We find that kinematic peculiar subsystems
are preferably formed in equal mass mergers. Equal-mass collisionless remnants
can show almost no rotation, regular rotation or strong kinematic misalignment.
The inclusion of gas makes the remnants appear more round(1:1) and
axisymmetric(3:1). Counter-Rotating Cores (CRCs) are almost exclusively formed
in equal-mass mergers with a dissipational component. 3:1 remnants show a much
more regular structure. We quantify these properties by applying the kinemetric
methods recently developed by Krajnovi\'c et al. This work will help to
understand observations of elliptical galaxies with 2D field spectrographs,
like SAURON.


title:
Design and manufacture of micro-optical arrays using 3D diamond
  machining techniques

abstract:
  We describe our work towards the manufacture of micro-optical arrays using
freeform diamond machining techniques. Simulations have been done to show the
feasibility of manufacturing micro-lens arrays using the slow-tool servo
method. Using this technique, master shapes can be produced for replication of
micro-lens arrays of either epoxy-on-glass or monolthic glass types. A machine
tool path programme has been developed on the machine software platform
DIFFSYS, allowing the production of spherical, aspherical and toric arrays. In
addition, in theory spatially varying lenslets, sparse arrays and dithered
lenslet arrays (for high contrast applications) are possible to produce. In
practice, due to the diamond tool limitations not all formats are feasible.
Investigations into solving this problem have been carried out and a solution
is presented here.


title: Absolute timing of the Crab Pulsar at optical wavelengths with STJs

abstract:
  We have observed the Crab Pulsar in the optical with S-Cam, an instrument
based on Superconducting Tunneling Junctions (STJs) with $\mu$s time
resolution. Our aim was to study the delay between the radio and optical pulse.
The Crab Pulsar was observed three times over a time span of almost 7 years, on
two different locations, using three different versions of the instrument, and
using two different GPS units. We consistently find that the optical peak leads
the radio peak by 49$\pm$90, 254$\pm$170, and 291$\pm$100 $\mu$s. On assumption
of a constant optical lead, the weighted-average value is $\sim$170 $\mu$s, or
when rejecting (based on a perhaps questionable radio ephemeris) the first
measurement, 273$\pm$100 $\mu$s.


title: Effects of alpha particles on the angular momentum loss from the Sun

abstract:
  The classic Weber-Davis model of the solar wind is reconsidered by
incorporating alpha particles and by allowing the solar wind to flow out of the
equatorial plane in an axisymmetrical configuration. In the ion momentum
equations of the solar wind, the ion gyro-frequency is many orders of magnitude
higher than any other frequency. This requires that the difference between
proton and alpha velocity vectors be aligned with the background magnetic
field. With the aid of this alignment condition, the governing equations of the
multi-fluid solar wind are derived from the standard transport equations. The
governing equations are numerically solved along a prescribed meridional
magnetic field line located at colatitude $70^\circ$ at 1AU and a steady state
fast solar wind solution is found. A general analysis concludes, in agreement
with the Weber-Davis model, that the magnetic field helps the coronal plasma to
achieve an effective corotation out to the Alfv\'enic radius, where the
poloidal Alfv\'enic Mach number $M_T$ equals unity ($M_T$ is defined by
equation (\ref{eq:mach})). The model computations show that, magnetic stresses
predominate the angular momentum loss of the Sun. For the fast wind considered,
the proton contribution to the angular momentum loss, which can be larger than
the magnetic one, is almost completely canceled by the alpha particles that
develop an azimuthal speed in the direction opposite to the solar rotation. The
Poynting flux associated with the azimuthal components is negligible in the
energy budget. However, the solar rotation can play some role in reducing the
relative speed between alpha particles and protons for low latitude fast solar
wind streams in interplanetary space.


title:
An alternative to grids and glasses: Quaquaversal pre-initial conditions
  for N-body simulations

abstract:
  N-body simulations sample their initial conditions on an initial particle
distribution, which for cosmological simulations is usually a glass or grid,
whilst a Poisson distribution is used for galaxy models, spherical collapse
etc. These pre-initial conditions have inherent correlations, noise due to
discreteness and preferential alignments, whilst the glass distribution is
poorly defined and computationally expensive to construct. We present a novel
particle distribution which can be useful as a pre-initial condition for N-body
simulations, using a simple construction based on a ``quaquaversal'' tiling of
space. This distribution has little preferred orientation (i.e. is
statistically isotropic), has a rapidly vanishing large scale power-spectrum
(P(k) ~ k^4), and is trivial to create. It should be particularly useful for
warm dark matter and cold collapse simulations.


title: Spectroscopic analysis of southern B and Be stars

abstract:
  Spectroscopic monitoring of 141 southern ﬁeld B type stars, 114 of
them known to exhibit the Be phenomenon, allowed the estimation of their
projected rotational velocities, effective temperatures and superﬁcial
gravities from both line and equivalent width ﬁtting procedures. Stellar
ages, masses and bolometric luminosities were derived from internal structure
models. Without taking into account for the effects of gravity darkening, we
notice the occurrence of the Be phenomenon in later stages of main sequence
phase.


title: A method for detection of structure

abstract:
  Context. In order to understand the evolution of molecular clouds it is
important to identify the departures from self-similarity associated with the
scales of self-gravity and the driving of turbulence.
  Aims. A method is described based on structure functions for determining
whether a region of gas, such as a molecular cloud, is fractal or contains
structure with characteristic scale sizes.
  Methods. Using artificial data containing structure it is shown that
derivatives of higher order structure functions provide a powerful way to
detect the presence of characteristic scales should any be present and to
estimate the size of such structures. The method is applied to observations of
hot H2 in the Kleinman-Low nebula, north of the Trapezium stars in the Orion
Molecular Cloud, including both brightness and velocity data. The method is
compared with other techniques such as Fourier transform and histogram
techniques.
  Results. It is found that the density structure, represented by H2 emission
brightness in the K-band (2-2.5micron), exhibits mean characteristic sizes of
110, 550, 1700 and 2700AU. The velocity data show the presence of structure at
140, 1500 and 3500AU. Compared with other techniques such as Fourier transform
or histogram, the method appears both more sensitive to characteristic scales
and easier to interpret.


title:
Superhumps in Binary Systems and Their Connection to Precessional Spiral
  Density Waves

abstract:
  We consider a mechanism for the formation of superhumps in the TV Col system,
based on the possible existence of a precessional spiral wave in the accretion
disk of the system. This mechanism can act in binaries with arbitrary
component-mass ratios, and our precessional spiral wave model can be applied to
explain observed superhumps of all types.


title:
Shapley Optical Survey II: The effect of environment on the
  colour-magnitude relation and galaxy colours

abstract:
  We present an analysis of the effects of environment on the photometric
properties of galaxies in the core of the Shapley Supercluster at z=0.05, one
of the most massive structures in the local universe. The Shapley Optical
Survey (SOS) comprises archive WFI optical imaging of a 2.0 deg^2 region
containing the rich clusters A3556, A3558 and A3562 which demonstrate a highly
complex dynamical situation including ongoing cluster mergers. The B-R/R
colour-magnitude relation has an intrinsic dispersion of 0.045 mag and is
0.015\pm0.005 mag redder in the highest-density regions, indicative of the red
sequence galaxy population being 500 Myr older in the cluster cores than
towards the virial radius. The B-R colours of galaxies are dependent on their
environment, whereas their luminosities are independent of the local density,
except for the very brightest galaxies (M_R<-22). The global colours of faint
(>M*+2) galaxies change from the cluster cores where ~90% of galaxies lie along
the cluster red sequence to the virial radius, where the fraction has dropped
to just ~20%. This suggests that processes related to the supercluster
environment are responsible for transforming faint galaxies, rather than galaxy
merging, which should be infrequent in any of the regions studied here. The
largest concentrations of faint blue galaxies are found between the clusters,
coincident with regions containing high fractions of ~L* galaxies with radio
emission indicating starbursts. Their location suggests star-formation
triggered by cluster mergers, in particular the merger of A3562 and the poor
cluster SC1329-313, although they may also represent recent arrivals in the
supercluster core complex. (abstract truncated)


title:
Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O,
  and their Isotopes

abstract:
  A solar photospheric "thermal profiling" analysis is presented, exploiting
the infrared rovibrational bands of carbon monoxide (CO) as observed with the
McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above
the Earth's atmosphere by the Shuttle-borne ATMOS experiment. Visible continuum
intensities and center-limb behavior constrained the temperature profile of the
deep photosphere, while CO center-limb behavior defined the thermal structure
at higher altitudes. The oxygen abundance was self consistently determined from
weak CO absorptions. Our analysis was meant to complement recent studies based
on 3-D convection models which, among other things, have revised the historical
solar oxygen (and carbon) abundance downward by a factor of nearly two;
although in fact our conclusions do not support such a revision. Based on
various considerations, an oxygen abundance of 700+/-100 ppm (parts per million
relative to hydrogen) is recommended; the large uncertainty reflects the model
sensitivity of CO. New solar isotopic ratios also are reported for 13C, 17O,
and 18O.


title: Cosmic Calibration

abstract:
  The complexity and accuracy of current and future precision cosmology
observational campaigns has made it essential to develop an efficient technique
for directly combining simulation and observational datasets to determine
cosmological and model parameters; a procedure we term calibration. Once a
satisfactory calibration of the underlying cosmological model is achieved,
independent predictions for new observations become possible. For this
procedure to be effective, robust characterization of the uncertainty in the
calibration process is highly desirable. In this Letter, we describe a
statistical methodology which can achieve both of these goals. An application
example based around dark matter structure formation simulations and a
synthetic mass power spectrum dataset is used to demonstrate the approach.


title: Molecular excitation in the Eagle nebula's fingers

abstract:
  Context: The M16 nebula is a relatively nearby Hii region, powered by O stars
from the open cluster NGC 6611, which borders to a Giant Molecular Cloud.
Radiation from these hot stars has sculpted columns of dense obscuring material
on a few arcmin scales. The interface between these pillars and the hot ionised
medium provides a textbook example of a Photodissociation Region (PDR).
  Aims: To constrain the physical conditions of the atomic and molecular
material with submillimeter spectroscopic observations.
  Methods: We used the APEX submillimeter telescope to map a ~3'x3' region in
the CO J=3-2, 4-3 and 7-6 rotational lines, and a subregion in atomic carbon
lines. We also observed C18O(3-2) and CO(7-6) with longer integrations on five
peaks found in the CO(3-2) map. The large scale structure of the pillars is
derived from the molecular lines' emission distribution. We estimate the
magnitude of the velocity gradient at the tips of the pillars and use LVG
modelling to constrain their densities and temperatures. Excitation
temperatures and carbon column densities are derived from the atomic carbon
lines.
  Results: The atomic carbon lines are optically thin and excitation
temperatures are of order 60 K to 100 K, well consistent with observations of
other Hii region-molecular cloud interfaces. We derive somewhat lower
temperatures from the CO line ratios, of order 40 K. The Ci/CO ratio is around
0.1 at the fingers tips.


title:
The surprising magnetic topology of tauSco: fossil remnant or dynamo
  output?

abstract:
  We report the discovery of a medium-strength (~0.5kG) magnetic field on the
young, massive star tauSco (B0.2V), which becomes the third-hottest magnetic
star known. Circularly polarized Zeeman signatures are clearly detected in
observations collected mostly with the ESPaDOnS spectropolarimeter, recently
installed on the 3.6-m Canada-France-Hawaii Telescope; temporal variability is
also clearly established in the polarimetry, and can be unambiguously
attributed to rotational modulation with a period close to 41d. Archival UV
spectra confirm that this modulation repeats over timescales of decades.
  By reconstructing the large-scale structure of its magnetic topology, we find
that the magnetic structure is unusually complex for a hot star. The surface
topology is dominated by a potential field, although a moderate toroidal
component is probably present. We fail to detect intrinsic temporal variability
of the magnetic structure over the 1.5-yr period of our spectropolarimetric
observations (in agreement with the stable temporal variations of the UV
spectra), and infer that any differential surface rotation must be very small.
  The topology of the extended magnetic field that we derive from the
photospheric magnetic maps is also more complex than a global dipole, and
features in particular a significantly warped torus of closed magnetic loops
encircling the star (tilted at about 90deg to the rotation axis), with
additional, smaller, networks of closed field lines. This topology appears to
be consistent with the exceptional Xray properties of tauSco and also provides
a natural explanation of the variability observed in wind-formed UV lines. We
conclude that its magnetic field is most probably a fossil remnant from the
star-formation stage.