title: Antisymmetric Metric Field as Dark Matter

abstract:
  We consider the generation and evolution of quantum fluctuations of a massive
nonsymmetric gravitational field (B-field) from inflationary epoch to matter
era in the simplest variant of the nonsymmetric theory of gravitation (NGT),
which consists of a gauge kinetic term and a mass term.
  We observe that quite generically a nonsymmetric metric field with mass, m_B
~ 0.03(H_I/10^(13) GeV)^4 eV, is a good dark matter candidate, where H_I
denotes the inflationary scale. The most prominent feature of this dark matter
is a peak in power at a comoving momentum, k ~ sqrt(m_B H_0)/(1+z_eq)^(1/4),
where z_eq is the redshift at equality. This scale corresponds roughly to the
Earth-Sun distance.


title: Probing Neutrino Dark Energy with Extremely High-Energy Cosmic Neutrinos

abstract:
  Recently, a new non-Standard Model neutrino interaction mediated by a light
scalar field was proposed, which renders the big-bang relic neutrinos of the
cosmic neutrino background a natural dark energy candidate, the so-called
Neutrino Dark Energy. As a further consequence of this interaction, the
neutrino masses become functions of the neutrino energy densities and are thus
promoted to dynamical, time/redshift dependent quantities. Such a possible
neutrino mass variation introduces a redshift dependence into the resonance
energies associated with the annihilation of extremely high-energy cosmic
neutrinos on relic anti-neutrinos and vice versa into Z-bosons. In general,
this annihilation process is expected to lead to sizeable absorption dips in
the spectra to be observed on earth by neutrino observatories operating in the
relevant energy region above 10^13 GeV. In our analysis, we contrast the
characteristic absorption features produced by constant and varying neutrino
masses, including all thermal background effects caused by the relic neutrino
motion. We firstly consider neutrinos from astrophysical sources and secondly
neutrinos originating from the decomposition of topological defects using the
appropriate fragmentation functions. On the one hand, independent of the nature
of neutrino masses, our results illustrate the discovery potential for the
cosmic neutrino background by means of relic neutrino absorption spectroscopy.
On the other hand, they allow to estimate the prospects for testing its
possible interpretation as source of Neutrino Dark Energy within the next
decade by the neutrino observatories ANITA and LOFAR.


title:
COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses V. The
  time delay in SDSS J1650+4251

abstract:
  Aims: Our aim is to measure the time delay between the two gravitationally
lensed images of the z = 1.547 quasar SDSS J1650+4251, in order to estimate the
Hubble constant H_0.
  Methods: Our measurement is based on R-band light curves with 57 epochs
obtained at Maidanak Observatory, in Uzbekistan, from May 2004 to September
2005. The photometry is performed using simultaneous deconvolution of the data,
which provides the individual light curves of the otherwise blended quasar
images. The time delay is determined from the light curves using two very
different numerical techniques, i.e., polynomial fitting and direct
cross-correlation. The time delay is converted into H_0 following analytical
modeling of the potential well.
  Results: Our best estimate of the time delay is Dt = 49.5 +/- 1.9 days, i.e.,
we reach a 3.8% accuracy. The R-band flux ratio between the quasar images,
corrected for the time delay and for slow microlensing, is F_A /F_B = 6.2 +/-
5%.
  Conclusions: The accuracy reached on the time delay allows us to discriminate
well between families of lens models. As for most other multiply imaged
quasars, only models of the lensing galaxy that have a de Vaucouleurs mass
profile plus external shear give a Hubble constant compatible with the current
most popular value (H_0 = 72 +/- 8 km s-1 Mpc-1). A more realistic singular
isothermal sphere model plus external shear gives H_0 = 51.7 +4.0 -3.0 km s-1
Mpc-1.


title: Systematic quantum corrections to screening in thermonuclear fusion

abstract:
  We develop a series expansion of the plasma screening length away from the
classical limit in powers of $\hbar^{2}$. It is shown that the leading order
quantum correction increases the screening length in solar conditions by
approximately 2% while it decreases the fusion rate by approximately $ 0.34%$.
We also calculate the next higher order quantum correction which turns out to
be approximately 0.05%.


title:
Swift and infra-red observations of the blazar 3C~454.3 during the giant
  X-ray flare of May 2005

abstract:
  We present the results of a series of Swift and quasi simultaneous
ground-based infra-red observations of the blazar 3C 454.3 carried out in
April-May 2005 when the source was 10 to 30 times brighter than previously
observed. We found 3C 454.3 to be very bright and variable at all frequencies
covered by our instrumentation. The broad-band Spectral Energy Distribution
(SED) shows the usual two-bump shape (in nu-nu f(nu) space) with the Infra-red,
optical and UV data sampling the declining part of the synchrotron emission
that, even during this extremely large outburst, had its maximum in the
far-infrared. The X-ray spectral data from the XRT and BAT instruments are flat
and due to inverse Compton emission. The remarkable SED observed implies that
at the time of the Swift pointings 3C 454.3 was one of the brightest objects in
the extragalactic sky with a gamma-ray emission similar or brighter than that
of 3C 279 when observed in a high state by EGRET. Time variability in the
optical-UV flux is very different from that in the X-ray data: while the first
component varied by about a factor two within a single exposure, but remained
approximately constant between different observations, the inverse Compton
component did not vary on short time-scales but changed by more than a factor
of 3 between observations separated by a few days. This different dynamical
behaviour illustrates the need to collect simultaneous multi-frequency data
over a wide range of time-scales to fully constrain physical parameters in
blazars.


title:
Rapid X-ray Declines and Plateaus in Swift GRB Light Curves Explained by
  A Highly Radiative Blast Wave

abstract:
  GRB X-ray light curves display rapid declines followed by a gradual
steepening or plateau phase in >~ 30% of GRBs in the Swift sample. Treating the
standard relativistic blastwave model in a uniform circumburst medium, it is
shown that if GRBs accelerate ultra-high energy cosmic rays through a Fermi
mechanism, then the hadronic component can be rapidly depleted by means of
photopion processes on time scales ~100 - 10^4 s after the GRB explosion. While
discharging the hadronic energy in the form of ultra-high energy cosmic ray
neutrals and escaping cosmic-ray ions, the blast wave goes through a strongly
radiative phase, causing the steep declines observed with Swift. Following the
discharge, the blast wave recovers its adiabatic behavior, forming the observed
plateaus or slow declines. These effects are illustrated by calculations of
model bolometric light curves. The results show that steep X-ray declines and
plateau features occur when GRB sources take place in rather dense media, with
n >~ 100 cc out to >~ 10^17 cm.


title:
Spitzer Space Telescope Infrared Imaging and Spectroscopy of the Crab
  Nebula

abstract:
  We present 3.6, 4.5, 5.8, 8.0, 24, and 70 micron images of the Crab Nebula
obtained with the Spitzer Space Telescope IRAC and MIPS cameras, Low- and
High-resolution Spitzer IRS spectra of selected positions within the nebula,
and a near-infrared ground-based image made in the light of [Fe II]1.644
micron. The 8.0 micron image, made with a bandpass that includes [Ar II]7.0
micron, resembles the general morphology of visible H-alpha and near-IR [Fe II]
line emission, while the 3.6 and 4.5 micron images are dominated by continuum
synchrotron emission. The 24 micron and 70 micron images show enhanced emission
that may be due to line emission or the presence of a small amount of warm dust
in the nebula on the order of less than 1% of a solar mass. The ratio of the
3.6 and 4.5 micron images reveals a spatial variation in the synchrotron power
law index ranging from approximately 0.3 to 0.8 across the nebula. Combining
this information with optical and X-ray synchrotron images, we derive a
broadband spectrum that reflects the superposition of the flatter spectrum jet
and torus with the steeper diffuse nebula, and suggestions of the expected
pileup of relativistic electrons just before the exponential cutoff in the
X-ray. The pulsar, and the associated equatorial toroid and polar jet
structures seen in Chandra and HST images (Hester et al. 2002) can be
identified in all of the IRAC images. We present the IR photometry of the
pulsar. The forbidden lines identified in the high resolution IR spectra are
all double due to Doppler shifts from the front and back of the expanding
nebula and give an expansion velocity of approximately 1264 km/s.


title:
Rotochemical Heating of Neutron Stars: Rigorous Formalism with
  Electrostatic Potential Perturbations

abstract:
  The electrostatic potential that keeps approximate charge neutrality in
neutron star matter is self-consistently introduced into the formalism for
rotochemical heating presented in a previous paper by Fernandez and
Reisenegger. Although the new formalism is more rigorous, we show that its
observable consequences are indistinguishable from those of the previous one,
leaving the conclusions of the previous paper unchanged.


title:
The DRaGONS Survey: A Search for High Redshift Radio Galaxies And
  Heavily Obscured AGNs

abstract:
  We present the first results from the Distant Radio Galaxies Optically
Non-detected in the SDSS (DRaGONS) Survey. Using a novel selection technique
for identifying high redshift radio galaxy (HzRG) candidates, a large sample of
bright (S_{1.4GHz} > 100mJy) radio sources from the FIRST survey having no
optical counterpart in the SDSS is compiled. K-band imaging with the FLAMINGOS
instrument on the 4-meter telescope at Kitt Peak for 96 such candidates allows
preliminary identification of HzRG candidates through the well-known K-z
relation. Of the initial candidates, we identify 70 with magnitudes brighter
than K \approx 19.5, and compute limiting magnitudes for the remainder.
Assigning redshifts based on the K-z Hubble diagram gives a mean redshift for
our sample of z=2.5 and a median redshift of z=2.0. This selection is also
sensitive to a previously unseen population of anomalously red radio galaxies
(r-K > 6.5-7), which may indicate significant obscuration at moderate
redshifts. These obscured objects can be used to test the completeness of QSO
surveys to the effects of reddenning. More than ten percent of our sample falls
into this category, which may represent a sizable radio loud population missing
from current optically selected AGN samples. We additionally identify 479
bright Extremely Red Objects (EROs) in the fields surrounding our HzRG
candidates, to a magnitude of K=17.5, within a non-contiguous area of 2.38
square degrees. This constitutes a small overdensity of EROs surrounding the
radio galaxy candidates over random fields, and we see possible evidence for a
physical association of the EROs with the radio galaxies. However, examining
the clustering of all K < 19.0 galaxies around the radio targets reveals no
evidence of a global galaxy excess.


title: Global Asymmetry of the Heliosphere

abstract:
  Opher et al. 2006 showed that an interstellar magnetic field parallel to the
plane defined by the deflection of interstellar hydrogen atoms can produce a
north/south asymmetry in the distortion of the solar wind termination shock.
This distortion is consistent with Voyager 1 and Voyager 2 observations of the
direction of field-aligned streaming of the termination shock particles
upstream the shock. The model also indicates that such a distortion will result
in a significant north/south asymmetry in the distance to the shock and the
thickness of heliosheath. The two Voyager spacecraft should reveal the nature
and degree of the asymmetry in the termination shock and heliosheath.


title: Fossil Biodiversity: Red Noise Plus Signal

abstract:
  We have examined the Fourier power spectrum as well as the Hurst exponent of
extinction, origination, and total biodiversity in the marine fossil record,
using a recently improved geologic timescale. We find all of them strongly
inconsistent with past claims of self-similarity as well as inconsistent with
random walk behavior. Instead, they are dominated by low-frequency power, with
approximate f^-2 power over one decade in frequency. The spectrum turns over at
about 10^8 y, lending plausibility to connections with galactic dynamics. Even
in the background of this low-frequency dominance, a previously noted 62 My
biodiversity cycle stands out with better than 99% confidence above the noise
level, accounting for about 35% of the total variance in the fossil
biodiversity record.


title: A History and Informal Assessment of the Slacker Astronomy Podcast

abstract:
  Slacker Astronomy is a weekly podcast that covers a recent astronomical news
event or discovery. The show has a unique style consisting of irreverent,
over-the-top humor combined with a healthy dose of hard science. According to
our demographic analysis, the combination of this style and the unique
podcasting distribution mechanism allows the show to reach audiences younger
and busier than those reached via traditional channels. We report on the
successes and challenges of the first year of the show, and provide an informal
assessment of its role as a source for astronomical news and concepts for its
approximately 15,500 weekly listeners.


title: Kinematics of the ultra-compact helium accretor AM Canum Venaticorum

abstract:
  We report on the results from a five-night campaign of high-speed
spectroscopy of the 17-minute binary AM Canum Venaticorum, obtained with the
4.2-m William Herschel Telescope on La Palma.
  We derive a mass ratio q=0.18+/-0.01 for AM CVn, which is significantly
higher than the value found in previous, less direct measurements. We discuss
the implications for AM CVn's evolutionary history and show that a helium star
progenitor scenario is strongly favoured. We further discuss the implications
for the interpretation of AM CVn's superhump behaviour, and for the
detectability of its gravitational-wave signal with LISA.
  Finally, we test the predictions of an eccentric, precessing disc that are
based on AM CVn's observed superhump behaviour. We limit the effective
eccentricity in the outermost part of the disc, where the resonances that drive
the eccentricity are thought to occur, to e=0.04+/-0.01, which is smaller than
previous models indicated.


title:
New perspectives on strong z=0.5 MgII absorbers: are halo-mass and
  equivalent width anti-correlated?

abstract:
  We measure the mean halo-mass of z=0.5 MgII absorbers using the
cross-correlation (over co-moving scales 0.05-13h^{-1}Mpc) between 1806 MgII
quasar absorption systems and ~250,000 Luminous Red Galaxies (LRGs), both
selected from the SDSS DR3. The MgII systems have rest-frame equivalent widths
W_r(2796)>=0.3A. From the ratio of the MgII-LRG cross-correlation to the
LRG-LRG auto-correlation, we find that the bias ratio between MgII absorbers
and LRGs is 0.65+/-0.08, which implies that the absorber host-galaxies have a
mean halo-mass 20-40 times smaller than that of the LRGs; the MgII absorbers
have halos of mean mass <logM_h(M_sol)>=11.94+/-0.31(stat)+/-0.25(sys). We
demonstrate that this statistical technique, which does not require any
spectroscopic follow-up, does not suffer from contaminants such as stars or
foreground and background galaxies. Finally, we find that the absorber
halo-mass is anti-correlated with the equivalent width. If MgII absorbers were
virialized in galaxy halos a positive M_h-W_r correlation would have been
observed since W_r(2796) is a direct measure of the velocity spread of the MgII
sub-components. Thus, our results demonstrate that the individual clouds of a
MgII system are not virialized in the gaseous halos of the host-galaxies. We
review past results in the literature on the statistics of MgII absorbers and
find that they too require an M_h-W_r anti-correlation. When combined with
measurements of the equivalent width distribution, the M_h-W_r anti-correlation
naturally explains why absorbers with W_r(2796)>=2A are not seen at large
impact parameters. We interpret the M_h-W_r anti-correlation within the
starburst scenario where strong MgII absorbers are produced by
supernovae-driven winds.


title:
Probing unexplored territories with MUSE: a second generation instrument
  for the VLT

abstract:
  The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT
panoramic integral-field spectrograph under preliminary design study. MUSE has
a field of 1x1 arcmin**2 sampled at 0.2x0.2 arcsec**2 and is assisted by the
VLT ground layer adaptive optics ESO facility using four laser guide stars. The
simultaneous spectral range is 465-930 nm, at a resolution of R~3000. MUSE
couples the discovery potential of a large imaging device to the measuring
capabilities of a high-quality spectrograph, while taking advantage of the
increased spatial resolution provided by adaptive optics. This makes MUSE a
unique and tremendously powerful instrument for discovering and characterizing
objects that lie beyond the reach of even the deepest imaging surveys. MUSE has
also a high spatial resolution mode with 7.5x7.5 arcsec**2 field of view
sampled at 25 milli-arcsec. In this mode MUSE should be able to obtain
diffraction limited data-cubes in the 600-930 nm wavelength range. Although the
MUSE design has been optimized for the study of galaxy formation and evolution,
it has a wide range of possible applications; e.g. monitoring of outer planets
atmosphere, environment of young stellar objects, super massive black holes and
active nuclei in nearby galaxies or massive spectroscopic surveys of stellar
fields in the Milky Way and nearby galaxies.


title:
Clustering of K-selected Galaxies at 2<z<3.5: Evidence for a
  Color-Density Relation

abstract:
  We study the clustering properties of K-selected galaxies at 2<z<3.5 using
deep multiwavelength imaging in three fields from the MUSYC survey. These are
the first measurements to probe the spatial correlation function of K-selected
galaxies in this redshift range on large scales, allowing for robust
conclusions about the dark matter halos that host these galaxies. K-selected
galaxies with K<21 have a correlation length r_0 ~ 6 h^-1 Mpc, larger than
typical values found for optically-selected galaxies. The correlation length
does not depend on K-band magnitude, but it does increase strongly with color;
the J-K>2.3 distant red galaxies (DRGs) have r_0 ~ 11 h^-1 Mpc. Contrary to
findings for optically-selected galaxies, K-selected galaxies that are faint in
the R-band cluster more strongly than brighter galaxies. These results suggest
that a color-density relation was in place at z>2. Our results indicate that
K-bright blue galaxies and K-bright red galaxies are fundamentally different,
as they have different clustering properties. Using a simple model of one
galaxy per halo, we infer halo masses ~ 5 x 10^12 M_sun for K<21 galaxies and ~
2 x 10^13 M_sun for DRGs. A comparison of the observed space density of DRGs to
the density of their host halos suggests large halo occupation numbers;
however, this result is at odds with the lack of a strong small-scale excess in
the angular correlation function. We find that the z=0 descendants of the
galaxies considered here reside primarily in groups and clusters. [abridged]


title: A search for binary systems among the nearest L dwarfs

abstract:
  We have used the NICMOS NIC1 camera on the Hubble Space Telescope to obtain
high angular resolution images of 51 ultracool dwarfs in the immediate Solar
Neighbourhood. Nine systems are resolved as binary, with component separations
from 1.5 and 15 AU. All of the systems have components with similar
luminosities, and, consequently, high mass ratios, q > 0.8. Limiting analysis
to L dwarfs within 20 parsecs, the observed binary fraction is 12(+7/-3).
Applying Bayesian analysis to our dataset, we derive a mass-ratio distribution
that peaks strongly at unity. Modelling the semi-major axis distribution as a
logarithmic Gaussian, the best fit is centered at log(a_0) = 0.8 AU (~6.3 AU),
with a (logarithmic) width of 0.3. The current data are consistent with an
overall binary frequency of ~24%.


title: Results from the GMT Ground-Layer Experiment at the Magellan Telescopes

abstract:
  We present results from our two year study of ground-layer turbulence as seen
through the 6.5-meter Magellan Telescopes at Las Campanas Observatory. The
experiment consists of multiple, moderate resolution, Shack-Hartmann wavefront
sensors deployed over a large 16 arcminute field. Over the two years of the
experiment, the ground-layer turbulence has been sampled on eleven nights in a
variety of seeing and wind conditions. On most nights the ground-layer
turbulence contributes 10% to the total visible-band seeing, although a few
nights exhibit ground-layer contributions up to 30%. We present the
ground-layer turbulence on the sampled nights as well as a demonstration of its
strength as a function of field size. This information is combined with data
from a MASS-DIMM seeing monitor adjacent to the Magellan Telescopes to infer
the annual ground-layer contribution to seeing at Las Campanas.


title: On the fraction of X-ray obscured quasars in the local universe

abstract:
  Recent wide area hard X-ray and soft Gamma ray surveys have shown that the
fraction of X-ray obscured AGNs in the local universe significantly decreases
with intrinsic luminosity. In this letter we point out that two correction have
to be made to the samples: 1) radio loud AGNs have to be excluded since their
X-ray emission might be dominated by the jet component; 2) Compton thick
sources have to be excluded too since their hard X-ray and soft gamma ray
emission are also strongly attenuated by Compton scattering. The soft gamma-ray
selected AGN samples obtained by SWIFT and INTEGRAL provide the best
opportunity to study the fraction of obscured AGN in the local universe in the
least biased way. We choose these samples to check if the corrections could
alter the above result on the fraction of obscured AGNs. We find that before
the corrections both samples show significant anti-correlation between L_X and
N_H, indicating obvious decrease in the fraction of obscured AGNs with
luminosity. However, after the corrections, we find only marginal evidence of
anti-correlation (at 98% confidence level) in the SWIFT sample, and no evidence
at all in the INTEGRAL sample which consists of comparable number of objects.
We conclude that current samples only show a marginal decrease in the fraction
of obscured AGNs in the local universe, and much larger samples are required to
reach a more robust conclusion.


title: Lyman Alpha Constraints on Very Low Luminosity AGN

abstract:
  Recent surveys have detected Lya emission from z=4.5-6.5 at luminosities as
low as 10^41 erg/s. There is good evidence that low numbers of AGN are among
observed faint Lya emitters. Combining these observations with an empirical
relation between the intrinsic Lya and B-band luminosities of AGN, we obtain an
upper limit on the number density of AGN with absolute magnitudes M_B=[-16,-19]
at z=4.5-6.5. These AGN are up to two orders of magnitude fainter than those
discovered in the Chandra Deep Field, resulting in the faintest observational
constraints to date at these redshifts. At z=4.5, the powerlaw slope of the
very faint end of the luminosity function of AGN is shallower than the slope
observed at lower redshifts, beta <1.6, at the 98% confidence level. In fact,
we find marginal evidence that the luminosity function rises with luminosity,
corresponding to a powerlaw slope beta <0, at magnitudes fainter than M_B~-20
(75% confidence level). These results suggest either that accretion onto lower
mass black holes is less efficient than onto their more massive counterparts,
or that the number of black holes powering AGN with M_B >-20 is lower than
expected from the M_BH-sigma relation by one-two orders of magnitude.
Extrapolating from reverberation-mapping studies suggests that these black
holes would have M_BH=10^6-10^7 Msun. To facilitate the identification of AGN
among observed Lya emitters, we derive observational properties of faint AGN in
the Lya line, as well as in the X-ray and optical bands.


title:
ChaMPlane Discovery of Candidate Symbiotic Binaries in Baade's and
  Stanek's Windows

abstract:
  We have searched the OGLE-II archive for candidate counterparts of X-ray
sources detected in two low-extinction windows included in our Galactic bulge
Chandra/HST survey. We find that a significant number - i.e. in excess of the
expected level of random associations - can be matched with probable M-giants.
Their X-ray properties can be understood if these sources are symbiotic
binaries where the X-rays are typically, either directly or indirectly, the
result of a white dwarf accreting from the wind of a cool giant. Optical and
near-infrared properties of selected sources are consistent with a symbiotic
nature, although none of the spectra collected for 8 out of 13 candidate
counterparts show the high-ionization nebular emission lines observed for many
symbiotics. The hard X-ray emission for several sources (power-law photon
indices -1.5 ~< Gamma ~< 1.5) suggests our sample includes systems similar to
the symbiotics recently detected with INTEGRAL and Swift.


title: Deployable Payloads with Starbug

abstract:
  We explore the range of wide field multi-object instrument concepts taking
advantage of the unique capabilities of the Starbug focal plane positioning
concept. Advances to familiar instrument concepts, such as fiber positioners
and deployable fiber-fed IFUs, are discussed along with image relays and
deployable active sensors. We conceive deployable payloads as components of
systems more traditionally regarded as part of telescope systems rather than
instruments - such as adaptive optics and ADCs. Also presented are some of the
opportunities offered by the truly unique capabilities of Starbug, such as
microtracking to apply intra-field distortion correction during the course of
an observation.


title:
HST/ACS Wide-Field Photometry of the Sombrero Galaxy Globular Cluster
  System

abstract:
  A detailed imaging analysis of the globular cluster (GC) system of the
Sombrero galaxy (NGC 4594) has been accomplished using a six-image mosaic from
the Hubble Space Telescope Advanced Camera for Surveys. The quality of the data
is such that contamination by foreground stars and background galaxies is
negligible for all but the faintest 5% of the GC luminosity function (GCLF).
This enables the study of an effectively pure sample of 659 GCs until ~2 mags
fainter than the turnover magnitude, which occurs at M_V=-7.60+/-0.06 for an
assumed m-M=29.77. Two GC metallicity subpopulations are easily
distinguishable, with the metal-poor subpopulation exhibiting a smaller
intrinsic dispersion in color compared to the metal-rich subpopulation.
  Three new discoveries include: (1) A metal-poor GC color-magnitude trend. (2)
Confirmation that the metal-rich GCs are ~17% smaller than the metal-poor ones
for small projected galactocentric radii (less than ~2 arcmin). However, the
median half-light radii of the two subpopulations become identical at ~3 arcmin
from the center. This is most easily explained if the size difference is the
result of projection effects. (3) The brightest (M_V < -9.0) members of the GC
system show a size-magnitude upturn where the average GC size increases with
increasing luminosity. Evidence is presented that supports an intrinsic origin
for this feature rather than a being result from accreted dwarf elliptical
nuclei. In addition, the metal-rich GCs show a shallower positive
size-magnitude trend, similar to what is found in previous studies of young
star clusters.


title:
SCUBA-2: a 10,000 pixel submillimeter camera for the James Clerk Maxwell
  Telescope

abstract:
  SCUBA-2 is an innovative 10,000 pixel submillimeter camera due to be
delivered to the James Clerk Maxwell Telescope in late 2006. The camera is
expected to revolutionize submillimeter astronomy in terms of the ability to
carry out wide-field surveys to unprecedented depths addressing key questions
relating to the origins of galaxies, stars and planets. This paper presents an
update on the project with particular emphasis on the laboratory commissioning
of the instrument. The assembly and integration will be described as well as
the measured thermal performance of the instrument. A summary of the
performance results will be presented from the TES bolometer arrays, which come
complete with in-focal plane SQUID amplifiers and multiplexed readouts, and are
cooled to 100mK by a liquid cryogen-free dilution refrigerator. Considerable
emphasis has also been placed on the operating modes of the instrument and the
common-user aspect of the user interface and data reduction pipeline. These
areas will also be described in the paper.


title: Electron Acceleration in Solar Flares: Theory of Spectral Evolution

abstract:
  Context: Stochastic acceleration is thought to be a key mechanism in the
energization of solar flare electrons.
  Aims: We study whether stochastic acceleration can reproduce the observed
soft-hard-soft evolution of the spectral features of the hard X-ray emitted by
suprathermal electron. We pay special attention to the effects of particle
trapping and escape.
  Methods: The Fokker-Planck equation for the electron distribution is
integrated numerically using the coefficients derived by Miller et al. for
transit-time damping acceleration. The electron spectra are then converted to
photon spectra for comparison with RHESSI observation of looptop sources.
  Results: The presence of particle escape softens the model spectra computed
in the stochastic acceleration framework. The ratio between the efficiency of
trapping and acceleration controls the spectral evolution which follows a
soft-hard-soft pattern. Furthermore, a pivot point (that is, a common crossing
point of the accelerated particle spectra at different times) is found at
around 10 keV. It can be brought into agreement with the observed value of 20
keV by enhanced trapping through an electric potential.
  Conclusions: The model proposed here accounts for the key features observed
in the spectral evolution of hard X-ray emission from looptop sources.


title:
Post processing of differential images for direct extrasolar planet
  detection from the ground

abstract:
  The direct imaging from the ground of extrasolar planets has become today a
major astronomical and biological focus. This kind of imaging requires
simultaneously the use of a dedicated high performance Adaptive Optics [AO]
system and a differential imaging camera in order to cancel out the flux coming
from the star. In addition, the use of sophisticated post-processing techniques
is mandatory to achieve the ultimate detection performance required. In the
framework of the SPHERE project, we present here the development of a new
technique, based on Maximum A Posteriori [MAP] approach, able to estimate
parameters of a faint companion in the vicinity of a bright star, using the
multi-wavelength images, the AO closed-loop data as well as some knowledge on
non-common path and differential aberrations. Simulation results show a 10^-5
detectivity at 5sigma for angular separation around 15lambda/D with only two
images.


title: Remarks on statistical errors in equivalent widths

abstract:
  Equivalent width measurements for rapid line variability in atomic spectral
lines are degraded by increasing error bars with shorter exposure times. We
derive an expression for the error of the line equivalent width
$\sigma(W_\lambda)$ with respect to pure photon noise statistics and provide a
correction value for previous calculations.


title: A New Universal Constant Determining Expansion of the Universe

abstract:
  A new universal constant of expansion has been discovered with amazing
predictive power once its density-time relations have been deciphered. The new
constant is kappa, the product of the gravitational constant, and the average
total mass-energy density of our universe and the square of the cosmic time.
With the ten parameters known, this relation promises to account for the
expansion of our universe from its beginning into the far future. The most
important and most difficult item is cosmic time and its scaling relation with
the densities. The new cosmological theory will be presented in this paper to
show good predictions of the cosmological parameters. The theory will be used
in a second paper to show that acceleration of the expansion rate is not needed
to account globally for the exploding-star supernova Ia radiation that has
traveled such great distances in our expanding universe.


title:
Comparison of the Ultra-High Energy Cosmic Ray Flux Observed by AGASA,
  HiRes and Auger

abstract:
  The current measurements of the cosmic ray energy spectrum at ultra-high
energies ($\text{E}>10^{19}$ eV) are characterized by large systematic errors
and poor statistics. In addition, the experimental results of the two
experiments with the largest published data sets, AGASA and HiRes, appear to be
inconsistent with each other, with AGASA seeing an unabated continuation of the
energy spectrum even at energies beyond the GZK cutoff energy at $10^{19.6}$
eV. Given the importance of the related astrophysical questions regarding the
unknown origin of these highly energetic particles, it is crucial that the
extent to which these measurements disagree be well understood. Here we
evaluate the consistency of the two measurements for the first time with a
model-independent method that accounts for the large statistical and systematic
errors of current measurements. We further compare the AGASA and HiRes spectra
with the recently presented Auger spectrum. The method directly compares two
measurements, bypassing the introduction of theoretical models for the shape of
the energy spectrum. The inconsistency between the observations is expressed in
terms of a Bayes Factor, a standard statistic defined as the ratio of a
separate parent source hypothesis to a single parent source hypothesis.
Application to the data shows that the two-parent hypothesis is disfavored. We
expand the method to allow comparisons between an experimental flux and that
predicted by any model.


title:
Panchromatic Properties of 99,000 Galaxies Detected by SDSS, and (some
  by) ROSAT, GALEX, 2MASS, IRAS, GB6, FIRST, NVSS and WENSS Surveys

abstract:
  We discuss the panchromatic properties of 99,088 galaxies selected from the
SDSS Data Release 1 spectroscopic sample (a flux-limited sample for 1360
deg^2). These galaxies are positionally matched to sources detected by ROSAT,
GALEX, 2MASS, IRAS, GB6, FIRST, NVSS and WENSS. We find strong correlations
between the detection fraction at other wavelengths and optical properties such
as flux, colors, and emission-line strengths. Using GALEX, SDSS, and 2MASS
data, we construct the UV-IR broad-band spectral energy distributions for
various types of galaxies, and find that they form a nearly one-parameter
family. For example, based on SDSS u- and r-band data, supplemented with
redshift, the K-band 2MASS magnitudes can be "predicted" with an rms scatter of
only 0.2 mag. When a dust content estimate determined from SDSS data by
Kauffmann et al. (2003) is also utilized, this scatter decreases to 0.1 mag. We
demonstrate that this dust content is indeed higher for galaxies detected by
IRAS and that it can be used to "predict" measured IRAS 60 micron flux density
within a factor of two using only SDSS data. We also show that the position of
a galaxy in the emission-line-based Baldwin-Phillips-Terlevich diagram is
correlated with the optical light concentration index and u-r color determined
from the SDSS broad-band imaging data, and discuss changes in the morphology of
this diagram induced by requiring detections at other wavelengths. We study the
IR-radio correlation and find evidence that its slope may be different for AGN
and star-forming galaxies and related to the H_alpha/H_beta line strength
ratio.


title: Is pulsar B0656+14 a very nearby RRAT source?

abstract:
  The recently discovered RRAT sources are characterized by very bright radio
bursts which, while being periodically related, occur infrequently. We find
bursts with the same characteristics for the known pulsar B0656+14. These
bursts represent pulses from the bright end of an extended smooth pulse-energy
distribution and are shown to be unlike giant pulses, giant micropulses or the
pulses of normal pulsars. The extreme peak-fluxes of the brightest of these
pulses indicates that PSR B0656+14, were it not so near, could only have been
discovered as an RRAT source. Longer observations of the RRATs may reveal that
they, like PSR B0656+14, emit weaker emission in addition to the bursts.


title: Effects of Secular Interactions in Extrasolar Planetary Systems

abstract:
  This paper studies the effects of dynamical interactions among the planets in
observed extrasolar planetary systems, including hypothetical additional
bodies, with a focus on secular perturbations. These interactions cause the
eccentricities of the planets to explore a distribution of values over time
scales that are long compared to observational time baselines, but short
compared to the age of the systems. The same formalism determines the
eccentricity forcing of hypothetical test bodies (terrestrial planets) in these
systems and we find which systems allow for potentially habitable planets. Such
planets would be driven to nonzero orbital eccentricity and we derive the
distribution of stellar flux experienced by the planets over the course of
their orbits. The general relativistic corrections to secular interaction
theory are included in the analysis and such effects are important in systems
with close planets ($\sim$4 day orbits). Some extrasolar planetary systems
(e.g., Upsilon Andromedae) can be used as a test of general relativity, whereas
in other systems, general relativity can be used to constrain the system
parameters (e.g., $\sin i \gta 0.93$ for HD160691). For the case of hot
Jupiters, we discuss how the absence of observed eccentricity implies the
absence of companion planets.


title:
Images of Vega Dust Ring at 350 and 450 microns: New Clues to the
  Trapping of Multiple-Sized Dust Particles in Planetary Resonances

abstract:
  We have used the SHARC II camera at Caltech Submillimeter Observatory to make
350 and 450 micron images of the Vega dust disk at spatial resolutions (FWHM)
of 9.7" and 11.1", respectively. The images show a ring-like morphology (radius
\~ 100 AU) with inhomogeneous structure that is qualitatively different from
that previously reported at 850 microns and longer wavelengths. We attribute
the 350/450 micron emission to a grain population whose characteristic size (~
1 mm) is intermediate between that of the cm-sized grains responsible for
emission longward of 850 microns and the much smaller grains (< 18 microns) in
the extensive halo, visible at 70 microns, discussed by Su et al. (2005). We
have combined our submillimeter images with Spitzer data at 70 microns to
produce 2-d maps of line-of-sight optical depth (relative column density).
These "tau maps" suggest that the mm-sized grains are located preferentially in
three symmetrically-located concentrations. If so, then this structure could be
understood in terms of the Wyatt (2003) model in which planetesimals are
trapped in the mean motion resonances of a Neptune-mass planet at 65 AU,
provided allowance is made for the spatial distribution of dust grains to
differ from that of the parent planetesimals. The peaks of the tau maps are, in
fact, located near the expected positions corresponding to the 4:3 resonance.
If this identification is confirmed by future observations, it would resolve an
ambiguity with regard to the location of the planet.


title: Making sky maps from Planck data

abstract:
  We compare the performance of multiple codes written by different groups for
making polarized maps from Planck-sized, all-sky cosmic microwave background
(CMB) data. Three of the codes are based on a destriping algorithm; the other
three are implementations of an optimal maximum-likelihood algorithm.
Time-ordered data (TOD) were simulated using the Planck Level-S simulation
pipeline. Several cases of temperature-only data were run to test that the
codes could handle large datasets, and to explore effects such as the precision
of the pointing data. Based on these preliminary results, TOD were generated
for a set of four 217 GHz detectors (the minimum number required to produce I,
Q, and U maps) under two different scanning strategies, with and without noise.
Following correction of various problems revealed by the early simulation, all
codes were able to handle the large data volume that Planck will produce.
Differences in maps produced are small but noticeable; differences in computing
resources are large.


title:
Long Term Evolution of Close Planets Including the Effects of Secular
  Interactions

abstract:
  This paper studies the long term evolution of planetary systems containing
short-period planets, including the effects of tidal circularization, secular
excitation of eccentricity by companion planets, and stellar damping. For
planetary systems subject to all of these effects, analytic solutions (or
approximations) are presented for the time evolution of the semi-major axes and
eccentricities. Secular interactions enhance the inward migration and accretion
of hot Jupiters, while general relativity tends to act in opposition by
reducing the effectiveness of the secular perturbations. The analytic solutions
presented herein allow us to understand these effects over a wide range of
parameter space and to isolate the effects of general relativity in these
planetary systems.


title: $^3$He experimentum crucis for Dark Matter puzzles

abstract:
  The leading direct dark matter search experiments: CDMS, Edelweis and
DAMA/NaI exhibit different results for different approaches to the problem.
This contradiction can reflect a nontrivial and probably a multi-component
nature of the cosmological dark matter. WIMPs can possess dominantly a Spin
Dependent interaction with nucleons. They can be superheavy or represent
atom-like systems of superheavy charged particles. The Dark matter can contain
a component, which strongly interacts with the matter. We show that even a
moderate size superfluid $^3$He detector provides a crucial test for these
hypotheses and that its existing laboratory prototype is already of interest
for the experimental dark matter search.


title: Observational Constraints on the Acceleration Discrepancy Problem

abstract:
  I review the data relating to the appearance of the missing mass problem at a
particular acceleration scale. Rotation curves are examined in detail, with
emphasis on the empirical connection between baryonic and total mass
distributions. Other lines of evidence are also considered, including disk
stability, dwarf spheroidals, giant ellipticals, clusters of galaxies, the
microwave background, BBN, and the growth of large scale structure.


title: X-ray Properties of Black-Hole Binaries

abstract:
  We review the properties and behavior X-ray binaries that contain an
accreting black hole. The larger majority of such systems are X-ray transients,
and many of them were observed in daily pointings with RXTE throughout the
course of their outbursts. The complex evolution of these sources is described
in terms of common behavior patterns illustrated with comprehensive overview
diagrams for six selected systems. Central to this comparison are three X-ray
states of accretion, which are reviewed and defined quantitatively. Each state
yields phenomena that arise in strong gravitational fields. We sketch a
scenario for the potential impact of black hole observations on physics and
discuss a current frontier topic: the measurement of black hole spin.


title: Relations between concurrent hard X-ray sources in solar flares

abstract:
  Context: Solar flares release a large fraction of their energy into
non-thermal electrons, but it is not clear where and how. Bremsstrahlung X-rays
are observed from the corona and chromosphere.
  Aims: We aim to characterize the acceleration process by the coronal source
and its leakage toward the footpoints in the chromosphere. The relations
between the sources reflect the geometry and constrict the configuration of the
flare.
  Methods: We studied solar flares of GOES class larger than M1 with three or
more hard X-ray sources observed simultaneously in the course of the flare. The
events were observed with the X-ray satellite RHESSI from February 2002 until
July 2005. We used imaging spectroscopy methods to determine the spectral
evolution of each source in each event. The images of all of the five events
show two sources visible only at high energies (footpoints) and one source only
visible at low energies (coronal or looptop source, in two cases situated over
the limb).
  Results: We find soft-hard-soft behavior in both, coronal source and
footpoints. The coronal source is nearly always softer than the footpoints. The
footpoint spectra differ significantly only in one event out of five.
  Conclusions: The observations are consistent with acceleration in the coronal
source and an intricate connection between the corona and chromosphere.


title:
Do most planetary nebulae derive from binaries? I Population synthesis
  model of the galactic planetary nebula population produced by singlestars and
  binaries

abstract:
  We present a population synthesis calculation to derive the total number of
planetary nebulae (PN) in the Galaxy that descend from single stars and stars
in binary systems. Using the most recent literature results on galactic and
stellar formation as well as stellar evolution, we predict the total number of
galactic PNe with radii <0.9 pc to be (46,000 +/- 13,000). We do not claim this
to be the complete population, since there can be visible PNe with radii larger
than this limit. However, by taking this limit, we make our predicted
population inherently comparable to the observationally-based value of
Peimbert, who determined (7200 +/- 1800) PNe should reside in the Galaxy today.
Our prediction is discrepant with the observations at the 2.9-sigma level, a
disagreement which we argue is meaningful in view of our specific treatment of
the uncertainty. We conclude that it is likely that only a subset of the stars
thought to be capable of making a visible PN, actually do. In the second paper
in this series, an argument will be presented that the bulk of the galactic PN
population might be better explained if only binaries produce PNe.
  The predicted PN formation rate density from single stars and binaries is
(1.1 +/- 0.5) x 10^{-12} PN/yr per cubic pc in the local neighborhood. This
number is lower than the most recent PN birthrate density estimates of 2.1 x
10^{-12} PN/yr per cubic pc, which are based on local PN counts and the PN
distance scale, but more in line with the white dwarf birthrate densities
determined by Liebert et al. ((1.0 +/- 0.25) x 10^{-12} WD/yr per cubic pc).
The predicted PN birthrate density will be revised down, if we assume that only
binaries make PNe. This revision will imply that the PN distance scale has to
be revised to larger values.


title: The Rest-frame Optical Colors of 99,000 SDSS Galaxies

abstract:
  We synthesize the rest-frame Stroemgren colors using SDSS spectra for 99,088
galaxies selected from Data Release 1. This narrow-band ~200 AA photometric
system (uz, vz, bz, yz), first designed for the determination of effective
temperature, metallicity and gravity of stars, measures the continuum spectral
slope of galaxies in the rest-frame 3200-5800 AA wavelength range. Galaxies
form a remarkably narrow locus (~0.03 mag) in the resulting color-color
diagram. The Bruzual & Charlot population synthesis models suggest that the
position of a galaxy along this locus is controlled by a degenerate combination
of metallicity and age of the dominant stellar population. Galaxy distribution
along the locus is bimodal, with the local minimum corresponding to an ~1 Gyr
old single stellar population. The position perpendicular to the locus is
independent of metallicity and age, and reflects the galaxy's dust content, as
implied by both the models and the statistics of IRAS detections. A comparison
of this locus with the galaxy locus in the H_delta-D_n(4000) diagram, utilized
by Kauffmann et al. (2003) to estimate stellar masses, reveals a tight
correlation, although the two analyzed spectral ranges barely overlap. Overall,
the galaxy spectral energy distribution in the entire UV to near-IR range can
be described as a single-parameter family with an accuracy of 0.1 mag, or
better. This nearly one-dimensional distribution of galaxies in the
multi-dimensional space of measured parameters strongly supports the conclusion
of Yip et al. (2004), based on a principal component analysis, that SDSS galaxy
spectra can be described by a small number of eigenspectra. Apparently, the
contributions of stellar populations that dominate the optical emission from
galaxies are combined in a simple and well-defined way.


title:
Spitzer Survey of the Large Magellanic Cloud, Surveying the Agents of a
  Galaxy's Evolution (SAGE) I: Overview and Initial Results

abstract:
  We are performing a uniform and unbiased, ~7x7 degrees imaging survey of the
Large Magellanic Cloud (LMC), using the IRAC and MIPS instruments on board the
Spitzer Space Telescope in order to survey the agents of a galaxy's evolution
(SAGE), the interstellar medium (ISM) and stars in the LMC. The detection of
diffuse ISM with column densities >1.2x10^21 H cm^-2 permits detailed studies
of dust processes in the ISM. SAGE's point source sensitivity enables a
complete census of newly formed stars with masses >3 solar masses that will
determine the current star formation rate in the LMC. SAGE's detection of
evolved stars with mass loss rates >1x10^-8 solar masses per year will quantify
the rate at which evolved stars inject mass into the ISM of the LMC. The
observing strategy includes two epochs in 2005, separated by three months, that
both mitigate instrumental artifacts and constrain source variability. The SAGE
data are non-proprietary. The data processing includes IRAC and MIPS pipelines
and a database for mining the point source catalogs, which will be released to
the community in support of Spitzer proposal cycles 4 and 5. We present initial
results on the epoch 1 data with a special focus on the N79 and N83 region. The
SAGE epoch 1 point source catalog has ~4 million sources. The point source
counts are highest for the IRAC 3.6 microns band and decrease dramatically
towards longer wavelengths consistent with the fact that stars dominate the
point source catalogs and that the dusty objects, e.g. young stellar objects
and dusty evolved stars that detected at the longer wavelengths, are rare in
comparison. We outline a strategy for identifying foreground MW stars, that may
comprise as much as 18% of the source list, and background galaxies, that may
comprise ~12% of the source list.


title: The role of project science in the Chandra X-ray Observatory

abstract:
  The Chandra X-ray Observatory, one of NASA's Great Observatories, has an
outstanding record of scientific and technical success. This success results
from the efforts of a team comprising NASA, its contractors, the Smithsonian
Astrophysical Observatory, the instrument groups, and other elements of the
scientific community -- including the thousands of scientists who utilize this
powerful facility for astrophysical research. We discuss the role of NASA
Project Science in the formulation, development, calibration, and operation of
the Chandra X-ray Observatory. In addition to serving as an interface between
the scientific community and the Project, Project Science performed what we
term "science systems engineering". This activity encompasses translation of
science requirements into technical requirements and assessment of the
scientific impact of programmatic and technical trades. We briefly describe
several examples of science systems engineering conducted by Chandra Project
Science.


title: Magneto-Rotational Transport in the Early Sun

abstract:
  Angular momentum transport must have occurred in the Sun's radiative zone to
explain its current solid body rotation. We survey the stability of the early
Sun's radiative zone with respect to diffusive rotational instabilities, for a
variety of plausible past configurations. We find that the (faster rotating)
early Sun was prone to rotational instabilities even if only weak levels of
radial differential rotation were present, while the current Sun is not.
Stability domains are determined by approximate balance between dynamical and
diffusive timescales, allowing generalizations to other stellar contexts.
Depending on the strength and geometry of the weak magnetic field present, the
fastest growing unstable mode can be hydrodynamic or magneto-hydrodynamic (MHD)
in nature. Our results suggest that diffusive MHD modes may be more efficient
at transporting angular momentum than their hydrodynamic
(``Goldreich-Schubert-Fricke'') counterparts because the minimum spatial scale
required for magnetic tension to be destabilizing limits the otherwise very
small scales favored by double-diffusive instabilities. Diffusive
magneto-rotational instabilities are thus attractive candidates for angular
momentum transport in the early Sun's radiative zone.


title: Astrometric Perturbations in Substructure Lensing

abstract:
  In recent years, gravitational lensing has been used as a means to detect
substructure in galaxy-sized halos, via anomalous flux ratios in
quadruply-imaged lenses. In addition to causing anomalous flux ratios,
substructure may also perturb the positions of lensed images at observable
levels. In this paper, we numerically investigate the scale of such astrometric
perturbations using realistic models of substructure distributions.
Substructure distributions that project clumps near the Einstein radius of the
lens result in perturbations that are the least degenerate with the best-fit
smooth macromodel, with residuals at the milliarcsecond scale. Degeneracies
between the center of the lens potential and astrometric perturbations suggest
that milliarcsecond constraints on the center of the lensing potential boost
the observed astrometric perturbations by an order of magnitude compared to
leaving the center of the lens as a free parameter. In addition, we discuss
methods of substructure detection via astrometric perturbations that avoid full
lens modeling in favor of local image observables and also discuss modeling of
systems with luminous satellites to constrain the masses of those satellites.


title:
The Dependence of the Mass Assembly History of Cold Dark Matter Halos on
  Environment

abstract:
  We show by means of a high-resolution N-body simulation how the mass assembly
histories of galaxy-size cold dark matter (CDM) halos depend on environment.
Halos in high density environments form earlier and a higher fraction of their
mass is assembled in major mergers, compared to low density environments. The
distribution of the present-day specific mass aggregation rate is strongly
dependent on environment. While in low density environments only ~20% of the
halos are not accreting mass at the present epoch, this fraction rises to ~80%
at high densities. At z=1 the median of the specific aggregation rate is ~4
times larger than at z=0 and almost independent on environment. All the
dependences on environment found here are critically enhanced by local
processes associated to subhalos because the fraction of subhalos increases as
the environment gets denser. The distribution of the halo specific mass
aggregation rate as well as its dependence on environment resemble the
relations for the specific star formation rate distribution of galaxies. An
analogue of the morphology-density relation is also present at the level of CDM
halos, being driven by the halo major merging history. Nevertheless, baryonic
processes are necessary in order to explain further details and the evolution
of the star formation rate-, color- and morphology-environment relations.


title:
Fragmentation of gravitationally unstable gaseous protoplanetary disks
  with radiative transfer

abstract:
  We report on the results of the first 3D SPH simulation of massive,
gravitationally unstable protoplanetary disks with radiative transfer. We adopt
a flux-limited diffusion scheme justified by the high opacity of most of the
disk. The optically thin surface of the disk cools as a blackbody. The disks
grow slowly in mass starting from a Toomre-stable initial condition to the
point at which they become marginally unstable. We find that gravitationally
bound clumps with masses close to a Jupiter mass can arise. Fragmentation
appears to be driven by vertical convective-like motions capable of
transporting the heat from the disk midplane to its surface on a timescale of
only about 40 years at 10 AU. A larger or smaller cooling efficiency of the
disk at the optically thin surface can promote or stifle fragmentation by
affecting the vertical temperature profile, which determines whether convection
can happen or not, and by regulating the accretion flow from optically thin
regions towards overdense regions. We also find that the chances of
fragmentation increase for a higher mean molecular weight $\mu$ since
compressional heating is reduced. Around a star with mass $1 M_{\odot}$ only
disks with $\mu \ge 2.4$, as expected for gas with a metallicity comparable to
solar or higher, fragment. This suggests that disk instability, like
core-accretion, should be more effective in forming gas giants at higher gas
metallicities, consistent with the observed correlation between metallicity of
the planet-hosting stars and frequency of planets


title:
Inner Rim of A Molecular Disk Spatially Resolved in Infrared CO Emission
  Lines

abstract:
  We present high-resolution infrared spectroscopy of the Herbig Ae star HD
141569 A in the CO v=2-1 transition. With the angular resolution attained by
the adaptive optics system, the gas disk around HD 141569 A is spatially
resolved down to its inner-rim truncation. The size of the inner clearing is
11+-2 AU in radius, close to the gravitational radius of the star. The rough
coincidence to the gravitational radius indicates that the viscous accretion
working together with the photoevaporation by the stellar radiation has cleared
the inner part of the disk.


title: Dwarf Galaxies of the Local Group

abstract:
  XMM-Newton and Chandra have ushered in a new era for the study of dwarf
galaxies in the Local Group. We provide an overview of the opportunities,
challenges, and some early results. The large number of background sources
relative to galaxy sources is a major theme. Despite this challenge, the
identification of counterparts has been possible, providing hints that the same
mechanisms producing X-ray sources in larger galaxies are active in dwarf
galaxies. A supersoft X-ray source within 2" of the supermassive black hole in
M32 may be a remnant of the tidal disruption of a giant, although other
explanations cannot be ruled out.


title: Ten Facts of Life for Distant Supersoft Sources

abstract:
  First discovered in the Magellanic Clouds and in the Milky Way, the largest
pools of luminous supersoft X-ray sources (SSSs) now known lie in M31 and in
more distant galaxies. Hundreds of newly-discovered SSSs are helping us to test
models for Type Ia supernovae and to identify SSSs that may represent a wider
range of physical systems, including accreting intermediate-mass black holes.
In this short report we list ten intriguing facts about distant SSSs.


title:
A 3-Dimensional study of the Local Environment of Bright IRAS Galaxies:
  The AGN/Starburst connection

abstract:
  We present a 3-dimensional study of the local ($\leq 100 h^{-1}$ kpc) and the
large scale ($\leq$ 1 $h^{-1}$ Mpc) environment of Bright IRAS Galaxies
(BIRGs). For this purpose we use 87 BIRGs located at high galactic latitudes
(with 0.008$\leq z \leq$0.018) as well as a control sample of non-active
galaxies having the same morphological, redshift and diameter size
distributions as the corresponding BIRG sample. Using the Center for
Astrophysics (CfA2) and Southern Sky Redshift Survey (SSRS) galaxy catalogues
($m_b\lesssim 15.5$)as well as our own spectroscopic observations
($m_b\lesssim19.0$) for a subsample of the original BIRG sample, we find that
the fraction of BIRGs with a close neighbor is significantly higher than that
of their control sample. Comparing with a related analysis of Sy1 and Sy2
galaxies of Koulouridis et al. (2006) we find that BIRGs have a similar
environment as Sy2s, although the fraction of BIRGs with a bright close
neighbor is even higher than that of Sy2 galaxies. An additional analysis of
the relation between FIR colors and the type of activity of each BIRG shows a
significant difference between the colors of strongly-interacting and
non-interacting starbursts and a resemblance between the colors of
non-interacting starbursts and Sy2s. Our results support the view where close
interactions can drive molecular clouds towards the galactic center, triggering
starburst activity and obscuring the nuclear activity. When the close neighbor
moves away, starburst activity is reduced with the simultaneous appearance of
an obscured (type 2) AGN. Finally, the complete disentanglement of the pair
gives birth to an unobscured (type 1) AGN.


title: Antenna-Coupled TES Bolometers for CMB Polarimetry

abstract:
  We have developed a completely lithographic antenna-coupled bolometer for CMB
polarimetry. The necessary components of a millimeter wave radiometer -- a beam
forming element, a band defining filter, and the TES detectors -- are
fabricated on a silicon chip with photolithography. The densely populated
antennas allow a very efficient use of the focal plane area. We have fabricated
and characterized a series of prototype devices. We find that their properties,
including the frequency and angular responses, are in good agreement with the
theoretical expectations. The devices are undergoing optimization for upcoming
CMB experiments.


title:
Size and properties of the narrow-line region in Seyfert-2 galaxies from
  spatially-resolved optical spectroscopy

abstract:
  While [OIII] narrow-band imaging is commonly used to measure the size of the
narrow-line regions (NLRs) in active galactic nuclei (AGNs), it can be
contaminated by emission from surrounding starbursts. Recently, we have shown
that long-slit spectroscopy provides a valuable alternative approach to probe
the size in terms of AGN photoionisation. Moreover, several parameters of the
NLR can be directly accessed. We here apply the same methods developed and
described for the Seyfert-2 galaxy NGC1386 to study the NLR of five other
Seyfert-2 galaxies by using high-sensitivity spatially-resolved optical
spectroscopy obtained at the VLT and the NTT. We probe the AGN-photoionisation
of the NLR and thus, its ``real'' size using diagnostic line-ratio diagrams.We
derive physical properties of the NLR such as reddening, ionisation parameter,
electron density, and velocity as a function of distance from the nucleus. For
NGC5643, the diagnostic diagrams unveil a similar transition between line
ratios falling in the AGN regime and those typical for HII regions as found for
NGC1386, thus determining the size of the NLR. For the other four objects, all
measured line ratios fall in the AGN regime. In almost all cases, both electron
density and ionisation parameter decrease with radius. Deviations from this
general behaviour (such as a secondary peak) seen in both the ionisation
parameter and electron density can be interpreted as signs of shocks from the
interaction of a radio jet and the NLR gas. In several objects, the gaseous
velocity distribution is characteristic for rotational motion in an (inclined)
emission-line disk in the centre. We compare our results to those of NGC1386
and show that the latter can be considered as prototypical also for this larger
sample. We discuss our findings in detail for each object.


title: E+A Galaxies with Blue Cores: Active Galaxies in Transition

abstract:
  HST ACS images reveal blue cores in four E+A, or post-starburst, galaxies.
Follow-up spectroscopy shows that these cores have LINER spectra. The existence
of LINERs, consistent with those in many elliptical galaxies, is yet one more
piece of evidence that these post-merger, post-starburst, bulge-dominated
galaxies will evolve into normal ellipticals. More interestingly, if LINERs are
powered by low-luminosity AGN, their presence in these E+As suggests that any
rapid growth phase of the central black hole ended in rough concert with the
cessation of star formation. This result emphasizes the importance of E+As for
exploring how the evolution of black holes and AGN may be tied to that of
galactic bulges.


title: Global Predictions of the Universal Constant of Expansion

abstract:
  The new spatial condensation cosmological theory, based on the new universal
constant of expansion, kappa = G Rho t^2 = 3/(32 Pi), is used to predict
measurements of the supernova Ia data with no acceleration of the expansion
rate of the universe. That goal was accomplished with the key assumption that
radiation travels on great circles on the surface of the supporting 4-D ball
towards the detector at the compounded velocity of Vc = Hr - c. The radiation
has traveled great distances from emission to measurement in the expanding
universe and is exactly suited to test the global predictions of a cosmological
theory. Problems of the current big bang theory are discussed. It will be shown
that a new method of analyzing the data does indeed show the simplicity and
consistency of the new theory in contrast to the old Friedmann big bang model.


title:
Measurements and analysis of helium-like triplet ratios in the X-ray
  spectra of O-type stars

abstract:
  We discuss new methods of measuring and interpreting the
forbidden-to-intercombination line ratios of helium-like triplets in the X-ray
spectra of O-type stars, including accounting for the spatial distribution of
the X-ray emitting plasma and using the detailed photospheric UV spectrum.
Measurements are made for four O stars using archival Chandra HETGS data. We
assume an X-ray emitting plasma spatially distributed in the wind above some
minimum radius R_0. We find minimum radii of formation typically in the range
of 1.25 < R_0 / R_* < 1.67, which is consistent with results obtained
independently from line profile fits. We find no evidence for anomalously low
f/i ratios and we do not require the existence of X-ray emitting plasmas at
radii that are too small to generate sufficiently strong shocks.


title: Modelling V838 Monocerotis as a Mergeburst Object

abstract:
  We discuss the main observational facts on the eruption of V838 Monocerotis
in terms of possible outburst mechanisms. We conclude that the stellar merger
scenario is the only one, which can consistently explain the observations.


title:
The Link between Submillimetre Galaxies and Luminous Ellipticals:
  Near-Infrared IFU Spectroscopy of Submillimetre Galaxies

abstract:
  We present two-dimensional spectroscopy covering the rest-frame wavelengths
of strong optical emission lines in six luminous submillimetre galaxies at
z=1.3--2.5. Together with HST ACS and NICMOS imaging we map the dynamics and
morphologies of these systems on scales from 4--11kpc. Four of the systems show
multiple components in their spatially-resolved spectra with average velocity
offsets of ~180km/s across 8kpc in projection. From the ensemble properties
from our survey and the literature, we estimate the typical dynamical masses of
bright sub-mm galaxies as (5+/-3) x10^{11}Mo. This is similar to recent
estimates of their stellar masses -- suggesting that the dynamics of the
central regions of these galaxies are baryon dominated, with a substantial
fraction of those baryons in stars by the epoch of observation. Combining our
dynamical mass estimates with stellar luminosities for this population we
investigate whether submillimetre galaxies can evolve onto the Faber-Jackson
relation for local ellipticals. Adopting a typical lifetime of
tau_{burst}~300Myr for the submillimetre-luminous phase we find that the
stellar populations of sub-mm galaxies should fade to place them on the
Faber-Jackson relation, at M_K ~ -25.1. Furthermore, using the same starburst
lifetime we correct the observed space density of submillimetre galaxies for
the duty cycle to derive a volume density of the progenitors of ~1x10^{-4}
Mpc^{-3}. This is consistent with the space density of local luminous
early-type galaxies with M_K ~ -25.1, indicating that submillimetre galaxies
can evolve onto the scaling relations observed for local early-type galaxies,
and the observed population at z~2 is then sufficient to account for the
formation of the whole population of >~3 L^{*} ellipticals seen at z~0.


title:
Spherically symmetric solutions of modified field equations in f(R)
  theories of gravity

abstract:
  Spherically symmetric static empty space solutions are studied in f(R)
theories of gravity. We reduce the set of modified Einstein's equations to a
single equation and show how one can construct exact solutions in different
f(R) models. In particular, we show that for a large class models, including
e.g. the f(R)=R-\mu^4/R model, the Schwarzschild-de Sitter metric is an exact
solution of the field equations. The significance of these solutions is
discussed in light of solar system constraints on $f(R)$ theories of gravity.


title: Short-lived isotopes and 23Na production in low mass AGB Stars

abstract:
  We discuss the synthesis of some short-lived isotopes and of 23Na in
thermally pulsing AGB stars with initial mass of 2 Msun and two different
metallicities (Z=1.5e-2, corresponding to the metal amount in the Sun, and
Z=1e-4), representative of disk and halo stars, respectively. The different
nucleosynthesis channels are illustrated in some details. As previously found,
the 13C formed after each third dredge up episode is usually completely
consumed by alpha captures before the onset of the subsequent thermal pulse,
releasing neutrons. This is the most efficient neutron source in low mass AGB
stars and the resulting s-process nucleosynthesis is at the origin of the solar
main component. However, in the solar metallicity model, we find that the
temperature of the first formed 13C pocket remains too low during the
interpulse and the 13C is not completely burnt, being partially engulfed in the
convective zone generated by the following thermal pulse. Due to the rapid
convective mixing in this zone, the 13C is exposed to a larger temperature and
a nucleosynthesis characterized by a relatively high neutron density develops.
The main effect is the strong enhancement of isotopes located beyond some
critical branching in the neutron-capture path, like 60Fe, otherwise only
marginally produced during a standard s-process nucleosynthesis.


title: Tearing instability in relativistic magnetically dominated plasmas

abstract:
  Many astrophysical sources of high energy emission, such as black hole
magnetospheres, superstrongly magnetized neutron stars (magnetars), and
probably relativistic jets in Active Galactic Nuclei and Gamma Ray Bursts
involve relativistically magnetically dominated plasma. In such plasma the
energy density of magnetic field greatly exceeds the thermal and the rest mass
energy density of particles. Therefore the magnetic field is the main reservoir
of energy and its dissipation may power the bursting emission from these
sources, in close analogy to Solar flares. One of the principal dissipative
instabilities that may lead to release of magnetic energy is the tearing
instability. In this paper we study, both analytically and numerically, the
development of tearing instability in relativistically magnetically-dominated
plasma using the framework of resistive magnetodynamics. We confirm and
elucidate the previously obtained result on the growth rate of the tearing
mode: the shortest growth time is the same as in the case of classical
non-relativistic MHD, namely $\tau =\sqrt{\tau_a \tau_d}$ where $\tau_a$ is the
\Alfven crossing time and $\tau_d$ is the resistive time of a current layer.


title: The Atacama Large Millimeter/submillimeter Array: Overview & status

abstract:
  The Atacama Large Millimeter/submillimeter Array (ALMA) is an international
radio telescope under construction in the Atacama Desert of northern Chile.
ALMA will be situated on a high-altitude site at 5000 m elevation which
provides excellent atmospheric transmission over the instrument wavelength
range of 0.3 to 3 mm. ALMA will be comprised of two key observing components:
an array of up to sixty-four 12-m diameter antennas arranged in a multiple
configurations ranging in size from 0.15 to ~14 km, and a set of four 12-m and
twelve 7-m antennas operating in closely-packed configurations ~50m in diameter
(known as the Atacama Compact Array, or ACA), providing both interferometric
and total-power astronomical information. High-sensitivity dual-polarization 8
GHz-bandwidth spectral-line and continuum measurements between all antennas
will be available from two flexible digital correlators.


title: Redshift distribution of gamma-ray bursts and star formation rate

abstract:
  The redshift distribution of gamma-ray bursts collected in the BATSE Catalog
is compared with the star formation rate. We aim to clarify the accordance
between them. We also study the case of comoving number density of bursts
monotonously increasing up to redshift 6-20. A method independent of the models
of the gamma-ray bursts is used. The short and the long subgroups are studied
separately. The redshift distribution of the long bursts may be proportional to
the star formation rate. For the short bursts this can also happen, but the
proportionality is less evident. For the long bursts the monotonously
increasing scenario is also less probable but still can occur. For the short
bursts this alternative seems to be excluded.


title:
Study of the scientific potential of a three 40 cm Telescopes
  Interferometer at Dome C

abstract:
  Recent site testing (see:
http://www-luan.unice.fr/Concordiastro/indexantartic.html) has shown that Dome
C in Antarctica might have a high potential for stellar interferometry if some
solutions related to the surface atmospheric layer are found. A demonstrator
interferometer could be envisioned in order to fully qualify the site and
prepare the future development of a large array.
  We analyse the performances of a prototype interferometer for Dome C made
with 3 telescopes of 40 cm diameter. It assumes classical Michelson
recombination. The most recent atmospheric and environmental conditions
measured at Dome C are considered (see K. Agabi "First whole atmosphere
night-time seeing measurements at Dome C, Antarctica"). We also study the
possible science reachable with such a demonstrator. Especially we evaluate
that even such small aperture interferometer could allow the detection and low
resolution spectroscopy of the most favourable pegaside planets.


title:
Early-type stars in the young open cluster IC1805. II. The probably
  single stars HD15570 and HD15629, and the massive binary/triple system
  HD15558

abstract:
  Aims: We address the issue of the multiplicity of the three brightest
early-type stars of the young open cluster IC1805, namely HD15570, HD15629 and
HD15558. Methods: For the three stars, we measured the radial velocity by
fitting Gaussian curves to line profiles in the optical domain. In the case of
the massive binary HD15558, we also used a spectral disentangling method to
separate the spectra of the primary and of the secondary in order to derive the
radial velocities of the two components. These measurements were used to
compute orbital solutions for HD15558. Results: For HD15570 and HD15629, the
radial velocities do not present any significant trend attributable to a binary
motion on time scales of a few days, nor from one year to the next. In the case
of HD15558 we obtained an improved SB1 orbital solution with a period of about
442 days, and we report for the first time on the detection of the spectral
signature of its secondary star. We derive spectral types O5.5III(f) and O7V
for the primary and the secondary of HD15558. We tentatively compute a first
SB2 orbital solution although the radial velocities from the secondary star
should be considered with caution. The mass ratio is rather high, i.e. about 3,
and leads to very extreme minimum masses, in particular for the primary object.
Minimum masses of the order of 150 \pm 50 and 50 \pm 15 M_\odot are found
respectively for the primary and the secondary. Conclusions: We propose that
HD15558 could be a triple system. This scenario could help to reconcile the
very large minimum mass derived for the primary object with its spectral type.
In addition, considering new and previously published results, we find that the
binary frequency among O-stars in IC1805 has a lower limit of 20%, and that
previously published values (80%) are probably overestimated.


title: Near-IR variability properties of a selected sample of AGB stars

abstract:
  We present the results of a near-infrared monitoring programme of a selected
sample of stars, initially suspected to be Mira variables and OH/IR stars,
covering more than a decade of observations. The objects monitored cover the
typical range of IRAS colours shown by O-rich stars on the Asymptotic Giant
Branch and show a surprisingly large diversity of variability properties. 16
objects are confirmed as large-amplitude variables. Periods between 360 and
1800 days and typical amplitudes from 1 to 2 magnitudes could be determined for
nine of them. In three light curves we find a systematic decrease of the mean
brightness, two light curves show pronounced asymmetry. One source, IRAS
07222-2005, shows infrared colours typical of Mira variables but pulsates with
a much longer period (approx. 1200 days) than a normal Mira. Two objects are
ither close to (IRAS 03293+6010) or probably in (IRAS 18299-1705) the post-AGB
phase. In IRAS 16029-3041 we found a systematic increase of the H-K colour of
approximately 1 magnitude, which we interpret as evidence of a recent episode
of enhanced mass loss. IRAS 18576+0341, a heavily obscured Luminous Blue
Variable was also monitored. The star showed a continued decrease of brightness
over a period of 7 years (1995 - 2002).


title: The Rotation Measure and 3.5mm Polarization of Sgr A*

abstract:
  We report the detection of variable linear polarization from Sgr A* at a
wavelength of 3.5mm, the longest wavelength yet at which a detection has been
made. The mean polarization is 2.1 +/- 0.1% at a position angle of 16 +/- 2 deg
with rms scatters of 0.4% and 9 deg over the five epochs. We also detect
polarization variability on a timescale of days. Combined with previous
detections over the range 150-400GHz (750-2000 microns), the average
polarization position angles are all found to be consistent with a rotation
measure of -4.4 +/- 0.3 x 10^5 rad/m^2. This implies that the Faraday rotation
occurs external to the polarized source at all wavelengths. This implies an
accretion rate ~0.2 - 4 x 10^-8 Msun/yr for the accretion density profiles
expected of ADAF, jet and CDAF models and assuming that the region at which
electrons in the accretion flow become relativistic is within 10 R_S. The
inferred accretion rate is inconsistent with ADAF/Bondi accretion. The
stability of the mean polarization position angle between disparate
polarization observations over the frequency range limits fluctuations in the
accretion rate to less than 5%. The flat frequency dependence of the inter-day
polarization position angle variations also makes them difficult to attribute
to rotation measure fluctuations, and suggests that both the magnitude and
position angle variations are intrinsic to the emission.


title:
Chandra X-ray Sources in the Collapsed-Core Globular Cluster M30 (NGC
  7099)

abstract:
  We report the detection of six discrete, low-luminosity (Lx < 10^33 erg/s)
X-ray sources, located within 12 arcsec of the center of the collapsed-core
globular cluster M30 (NGC 7099), and a total of 13 sources within the half-mass
radius, from a 50 ksec Chandra ACIS-S exposure. Three sources lie within the
very small upper limit of 1.9 arcsec on the core radius. The brightest of the
three core sources has a luminosity of Lx (0.5-6 keV) = 6x10^32 erg/s and a
blackbody-like soft X-ray spectrum, which are both consistent with it being a
quiescent low-mass X-ray binary (qLMXB). We have identified optical
counterparts to four of the six central sources and a number of the outlying
sources, using deep Hubble Space Telescope and ground-based imaging. While the
two proposed counterparts that lie within the core may represent chance
superpositions, the two identified central sources that lie outside of the core
have X-ray and optical properties consistent with being CVs. Two additional
sources outside of the core have possible active binary counterparts. We
discuss the X-ray source population of M30 in light of its collapsed-core
status.


title: A High-Altitude, Station-Keeping Astronomical Platform

abstract:
  Several commercial telecommunication ventures together with a well funded US
military program make it a likely possibility that an autonomous,
high-altitude, light-than-air (LTA) vehicle which could maneuver and
station-keep for weeks to many months will be a reality in a few years. Here I
outline how this technology could be used to develop a high-altitude
astronomical observing platform which could return high-resolution optical data
rivaling those from space-based platforms but at a fraction of the cost.


title:
Discovery of a cluster of galaxies behind the Milky Way: X-ray and
  optical observations

abstract:
  We report the discovery of Cl 2334+48, a rich cluster of galaxies in the Zone
of Avoidance, identified in public images from the XMM-Newton archive. We
present the main properties of this cluster using the XMM-Newton X-ray data,
along with new optical spectroscopic and photometric observations. Cl 2334+48
is located at z = 0.271 +/- 0.001, as derived from the optical spectrum of the
brightest member galaxy. Such redshift agrees with a determination from the
X-ray spectrum (z = 0.263 (+0.012/-0.010)), in which an intense emission line
is matched to the rest wavelength of the Fe Kalpha complex. Its intracluster
medium has a plasma temperature of 4.92 (+0.50/-0.48) keV, sub-solar abundance
(0.38 +/- 0.12 Zsun), and a bolometric luminosity of 3.2 x 10^44 erg/s. A
density contrast delta = 2500 is obtained in a radius of 0.5 Mpc/h70, and the
corresponding enclosed mass is 1.5 x 10^14 Msun. Optical images show an
enhancement of g'-i' > 2.5 galaxies around the central galaxy, as expected if
these were cluster members. The central object is a luminous E-type galaxy,
which is displaced ~ 40 kpc/h70 from the cluster X-ray center. In addition, it
has a neighbouring arc-like feature (~ 22" or 90 kpc/h70 from it), probably due
to strong gravitational lensing. The discovery of Cl 2334+48 emphasises the
remarkable capability of the XMM-Newton to reveal new clusters of galaxies in
the Zone of Avoidance.


title: Globular cluster systems of six shell galaxies

abstract:
  Shells in Elliptical Galaxies are faint, sharp-edged features, believed to
provide evidence of a recent ($\sim 0.5 - 2 \times 10^9$ years ago) merger
event. We analyse the Globular Cluster (GC) systems of six shell elliptical
galaxies, to examine the effects of mergers upon the GC formation history. We
examine the colour distributions, and investigate differences between red and
blue globular cluster populations. We present luminosity functions, spatial
distributions and specific frequencies ($S_N$) at 50 kpc radius for our sample.
We present V and I magnitudes for cluster candidates measured with the HST
Advanced Camera for Surveys (ACS). Galaxy background light is modelled and
removed, and magnitudes are measured in 8 pixel (0.4 arcsec) diameter
apertures. Background contamination is removed using counts from HDFS. We find
that the colour distributions for NGC 3923 and NGC 5982 have a bimodal form
typical of bright ellipticals, with peaks near $V-I=0.92 \pm 0.04$ and
$V-I=1.18 \pm 0.06$. In NGC 7626, we find in addition a population of
abnormally luminous clusters at $M_I=-12.5$. In NGC 2865 we find an unusually
blue population, which may also be young. In NGC1344 and NGC474 the red cluster
population is marginally detected. The radial surface density profiles are more
flattened than the galaxy light in the cores. As already known, in NGC3923,
which has a high $S_N$ of 5.6, the radial density distribution is more
shallower than the diffuse galaxy light. The clusters in NGC 2865 and NGC 7626
provide evidence for formation of a population associated with a recent merger.
In the other galaxies, the properties of the clusters are similar to those
observed in other, non-shell, elliptical galaxies.


title:
Number counts and clustering properties of bright Distant Red Galaxies
  in the UKIDSS Ultra Deep Survey Early Data Release

abstract:
  We describe the number counts and spatial distribution of 239 Distant Red
Galaxies (DRGs), selected from the Early Data Release of the UKIDSS Ultra Deep
Survey. The DRGs are identified by their very red infrared colours with
(J-K)AB>1.3, selected over 0.62 sq degree to a 90% completeness limit of
KAB~20.7. This is the first time a large sample of bright DRGs has been studied
within a contiguous area, and we provide the first measurements of their number
counts and clustering. The population shows strong angular clustering,
intermediate between those of K-selected field galaxies and
optical/infrared-selected Extremely Red Galaxies. Adopting the redshift
distributions determined from other recent studies, we infer a high correlation
length of r0~11 h-1 Mpc. Such strong clustering could imply that our galaxies
are hosted by very massive dark matter halos, consistent with the progenitors
of present-day L>L* elliptical galaxies.


title: Dark Supergiant: Chandra's Limits on X-rays from Betelgeuse

abstract:
  We have analyzed Chandra calibration observations of Betelgeuse (alpha Ori,
M2Iab, m_V=0.58, 131 pc) obtained at the aimpoint locations of the HRC-I (8
ks), HRC-S (8 ks), and ACIS-I (5 ks). Betelgeuse is undetected in all the
individual observations as well as cumulatively. We derive upper limits to the
X-ray count rates and compute the corresponding X-ray flux and luminosity upper
limits for coronal plasma that may potentially exist in the atmosphere of
Betelgeuse over a range of temperatures, T=0.3-10 MK. We place a flux limit at
the telescope of fx ~ 4x10^(-15) ergs s^(-1) cm^(-2) at T=1 MK. The upper limit
is lowered by a factor of ~3 at higher temperatures, roughly an order of
magnitude lower than that obtained previously. Assuming that the entire stellar
surface is active, these fluxes correspond to a surface flux limit that ranges
from 30-7000 ergs s^(-1) cm^(-2) at T=1 MK, to ~1 ergs s^(-1) cm^(-2) at higher
temperatures, five orders of magnitude below the quiet Sun X-ray surface flux.
We discuss the implications of our analysis in the context of models of a
buried corona and a pervasive magnetic carpet. We rule out the existence of a
solar-like corona on Betelgeuse, but cannot rule out the presence of low-level
emission on the scale of coronal holes.


title: Donut: measuring optical aberrations from a single extra-focal image

abstract:
  We propose a practical method to calculate Zernike aberrations from analysis
of a single long-exposure defocused stellar image. It consists in fitting the
aberration coefficients and seeing blur directly to a realistic image binned
into detector pixels. This "donut" method is different from curvature sensing
in that it does not make the usual approximation of linearity. We calculate the
sensitivity of this technique to detector and photon noise and determine
optimal parameters for some representative cases. Aliasing of high-order
un-modeled aberrations is evaluated and shown to be similar to a low-order
Shack-Hartmann sensor. The method has been tested with real data from the SOAR
and Blanco 4m telescopes.


title:
The Hard X-ray Spectral Slope as an Accretion-Rate Indicator in
  Radio-Quiet Active Galactic Nuclei

abstract:
  We present new XMM-Newton observations of two luminous and high
accretion-rate radio-quiet active galactic nuclei (AGNs) at z~2. Together with
archival X-ray and rest-frame optical spectra of three sources with similar
properties as well as 25 moderate-luminosity radio-quiet AGNs at z<0.5, we
investigate, for the first time, the dependence of the hard (>~2 keV) X-ray
power-law photon index on the broad H_beta emission-line width and on the
accretion rate across ~3 orders of magnitude in AGN luminosity. Provided the
accretion rates of the five luminous sources can be estimated by extrapolating
the well-known broad-line region size-luminosity relation to high luminosities,
we find that the photon indices of these sources, while consistent with those
expected from their accretion rates, are significantly higher than expected
from the widths of their H_beta lines. We argue that, within the limits of our
sample, the hard-X-ray photon index depends primarily on the accretion rate.


title: Star formation in the vicinity of the IC 348 cluster

abstract:
  Aims. We present molecular line observations of the southwestern part of the
IC 348 young cluster, and we use them together with NIR and mm continuum data
to determine the distribution of dense gas, search for molecular outflows, and
analyze the ongoing star formation activity in the region. Methods. Our
molecular line data consists of C18O(1--0) and N2H+(1--0) maps obtained with
the FCRAO telescope at a resolution of about 50'' and CO(2--1) data obtained
with the IRAM 30m telescope at a resolution of 11''. Results. The dense gas
southwest of IC 348 is concentrated in two groups of dense cores, each of them
with a few solar masses of material and indications of CO depletion at high
density. One of the core groups is actively forming stars, while the other
seems starless. There is evidence for at least three bipolar molecular outflows
in the region, two of them powered by previously identified Class 0 sources,
while the other one is powered by a still not well characterized low-luminosity
object. The ongoing star formation activity is producing a small stellar
subgroup in the cluster. Using the observed core characteristics and the star
formation rate in the cluster we propose that that similar episodes of stellar
birth may have produced the subclustering observed in the halo of IC 348.


title: On the formation of dwarf galaxies and stellar halos

abstract:
  Using analytic arguments and a suite of very high resolution (10^3 Msun per
particle) cosmological hydro-dynamical simulations, we argue that high
redshift, z ~ 10, M ~ 10^8 Msun halos, form the smallest `baryonic building
block' (BBB) for galaxy formation. These halos are just massive enough to
efficiently form stars through atomic line cooling and to hold onto their gas
in the presence of supernovae winds and reionisation. These combined effects,
in particular that of the supernovae feedback, create a sharp transition: over
the mass range 3-10x10^7 Msun, the BBBs drop two orders ofmagnitude in stellar
mass. Below ~2x10^7 Msun, galaxies will be dark with almost no stars and no
gas. Above this scale is the smallest unit of galaxy formation: the BBB.
  A small fraction (~100) of these gas rich BBBs fall in to a galaxy the size
of the Milky Way. Ten percent of these survive to become the observed LG dwarf
galaxies at the present epoch. Those in-falling halos on benign orbits which
keep them far away from the Milky Way or Andromeda manage to retain their gas
and slowly form stars - these become the smallest dwarf irregular galax ies;
those on more severe orbits lose their gas faster than they can form stars and
become the dwarf spheroidals. The remaining 90% of the BBBs will be accreted.
We show that this gives a metallicity and total stellar mass consistent with
the Milky Way old stellar halo (abridged).


title: Extended Curvaton reheating in inflationary models

abstract:
  The curvaton reheating in a non-oscillatory inflationary universe model is
studied in a Jordan-Brans-Dicke theory. For different scenarios, the
temperature of reheating is computed. The result tells us that the reheating
temperature becomes practically independent of the Jordan-Brans-Dicke parameter
$w$. This reheating temperature results to be quite different when compared
with that obtained from Einstein`s theory of gravity.


title: Very Energetic Gamma-Rays from Microquasars and Binary Pulsars

abstract:
  Compact astrophysical objects produce some of the highest energy light in the
universe. The challenge is to determine what mechanism produces these photons.


title:
Constraining Primordial Non-Gaussianities from the WMAP2 2-1 Cumulant
  Correlator Power Spectrum

abstract:
  We measure the 2-1 cumulant correlator power spectrum $C^{21}_l$, a
degenerate bispectrum, from the second data release of the Wilkinson Microwave
Anisotropy Probe (WMAP). Our high resolution measurements with SpICE span a
large configuration space ($\simeq 168\times999$) corresponding to the possible
cross-correlations of the maps recorded by the different differencing
assemblies. We present a novel method to recover the eigenmodes of the
correspondingly large Monte Carlo covariance matrix. We examine its eigenvalue
spectrum and use random matrix theory to show that the off diagonal terms are
dominated by noise. We minimize the $\chi^2$ to obtain constraints for the
non-linear coupling parameter $f_{NL} = 22 \pm 52 (1\sigma)$.


title:
High accuracy transit photometry of the planet OGLE-TR-113b with a new
  deconvolution-based method

abstract:
  A high accuracy photometry algorithm is needed to take full advantage of the
potential of the transit method for the characterization of exoplanets,
especially in deep crowded fields. It has to reduce to the lowest possible
level the negative influence of systematic effects on the photometric accuracy.
It should also be able to cope with a high level of crowding and with large
scale variations of the spatial resolution from one image to another. A recent
deconvolution-based photometry algorithm fulfills all these requirements, and
it also increases the resolution of astronomical images, which is an important
advantage for the detection of blends and the discrimination of false positives
in transit photometry. We made some changes to this algorithm in order to
optimize it for transit photometry and used it to reduce NTT/SUSI2 observations
of two transits of OGLE-TR-113b. This reduction has led to two very high
precision transit light curves with a low level of systematic residuals, used
together with former photometric and spectroscopic measurements to derive new
stellar and planetary parameters in excellent agreement with previous ones, but
significantly more precise.


title:
Chemical Abundance Study of One Red Giant Star in NGC 5694 : A Globular
  Cluster with Dwarf Spheroidals' Chemical Signature?

abstract:
  We report the abundance analysis of one red giant branch star in the
metal-poor outer halo globular cluster NGC 5694. We obtain [Fe/H] = -1.93,
based on the ionized lines, and our metallicity measurement is in good
agreement with previous estimates. We find that [Ca+Ti/2Fe] and [Cu/Fe] of NGC
5694 are about 0.3 -- 0.4 dex lower than other globular clusters with similar
metallicities, but similar to some LMC clusters and stars in some dwarf
spheroidal galaxies. Differences persist, however, in the abundances of neutron
capture elements. The unique chemical abundance pattern and the large
Galactocentric distance (30 kpc) and radial velocity (-138.6 +/- 1.0 km/sec)
indicate that NGC 5694 had an extragalactic origin.


title:
Telescope to Observe Planetary Systems (TOPS): a high throughput 1.2-m
  visible telescope with a small inner working angle

abstract:
  The Telescope to Observe Planetary Systems (TOPS) is a proposed space mission
to image in the visible (0.4-0.9 micron) planetary systems of nearby stars
simultaneously in 16 spectral bands (resolution R~20). For the ~10 most
favorable stars, it will have the sensitivity to discover 2 R_E rocky planets
within habitable zones and characterize their surfaces or atmospheres through
spectrophotometry. Many more massive planets and debris discs will be imaged
and characterized for the first time. With a 1.2m visible telescope, the
proposed mission achieves its power by exploiting the most efficient and robust
coronagraphic and wavefront control techniques. The Phase-Induced Amplitude
Apodization (PIAA) coronagraph used by TOPS allows planet detection at 2
lambda/d with nearly 100% throughput and preserves the telescope angular
resolution. An efficient focal plane wavefront sensing scheme accurately
measures wavefront aberrations which are fed back to the telescope active
primary mirror. Fine wavefront control is also performed independently in each
of 4 spectral channels, resulting in a system that is robust to wavefront
chromaticity.


title:
Search for Compact Extragalactic Radio Sources Near Massive Star Forming
  Regions

abstract:
  We have used the Very Large Array to search for compact milliarcsecond-size
radio sources near methanol masers in high-mass star-forming regions. Such
sources are required for Very Long Baseline Interferometry phase-referencing
observations. We conducted pointed observations of 234 compact sources found in
the NVSS survey and find 92 sources with unresolved components and synchrotron
spectral indexes. These sources are likely the cores of AGNs and, thus, good
candidates for astrometric calibrators.