title: Signals of Inflation in a Friendly String Landscape

abstract:
  Following Freivogel {\it et al} we consider inflation in a predictive (or
`friendly') region of the landscape of string vacua, as modeled by
Arkani-Hamed, Dimopoulos and Kachru. In such a region the dimensionful
coefficients of super-renormalizable operators unprotected by symmetries, such
as the vacuum energy and scalar mass-squareds are freely scanned over, and the
objects of study are anthropically or `environmentally' conditioned probability
distributions for observables. In this context we study the statistical
predictions of (inverted) hybrid inflation models, where the properties of the
inflaton are probabilistically distributed. We derive the resulting
distributions of observables, including the deviation from flatness
$|1-\Omega|$, the spectral index of scalar cosmological perturbations $n_s$
(and its scale dependence $dn_s/d\log k$), and the ratio of tensor to scalar
perturbations $r$. The environmental bound on the curvature implies a solution
to the $\eta$-problem of inflation with the predicted distribution of $(1-n_s)$
indicating values close to current observations. We find a relatively low
probability ($<3%$) of `just-so' inflation with measurable deviations from
flatness. Intermediate scales of inflation are preferred in these models.


title:
From Radio to X-ray: The Quiescent Atmosphere of the dMe Flare Star EV
  Lacertae

abstract:
  We report on multi-wavelength observations spanning radio to X-ray
wavelengths of the M dwarf flare star, EV Lacertae, probing the characteristics
of the outer atmospheric plasma from the upper chromosphere to the corona. We
detect the star at a wavelength of 2 cm (15 GHz) for the first time. UV and FUV
line profiles show evidence of nonthermal broadening, and the velocity width
appear to peak at lower temperatures than in the Sun; this trend is confirmed
in another active M dwarf flare star. Electron density measurements indicate
nearly constant electron pressures between $\log T=$5.2 and 6.4. At higher
coronal temperatures, there is a sharp increase of two orders of magnitude in
density (n$_{e}\sim10^{13}$ cm$^{-3}$ at $\log T=$6.9). X-ray, EUV, FUV and NUV
spectra constrain the DEM from the upper chromosphere through the corona. The
coronal pressures are inconsistent with the assumption of hydrostatic
equilibrium, either through EM modeling or application of scaling laws, and
imply large conductive loss rates and a large energy input at the highest
temperatures. The timescales for radiative and conductive losses in EV Lac's
upper atmosphere imply that significant continued heating must occur for the
corona to maintain its quiescent properties. The high frequency radio detection
requires the high temperature X-ray-emitting coronal plasma to be spatially
distinct from the radio emission source. Length scales in the low-temperature
corona are markedly larger than those in the high-temperature corona, further
suggestions of an inhomogeneous mixture of thermal and nonthermal coronal
plasma.


title:
Accurate Astrometry and Photometry of Saturated and Coronagraphic Point
  Spread Functions

abstract:
  Accurate astrometry and photometry of saturated and coronagraphic point
spread functions (PSFs) are fundamental to both ground- and space-based high
contrast imaging projects. For ground-based adaptive optics imaging,
differential atmospheric refraction and flexure introduce a small drift of the
PSF with time, and seeing and sky transmission variations modify the PSF flux
distribution. For space-based imaging, vibrations, thermal fluctuations and
pointing jitters can modify the PSF core position and flux. These effects need
to be corrected to properly combine the images and obtain optimal
signal-to-noise ratios, accurate relative astrometry and photometry of detected
objects as well as precise detection limits. Usually, one can easily correct
for these effects by using the PSF core, but this is impossible when high
dynamic range observing techniques are used, like coronagrahy with a
non-transmissive occulting mask, or if the stellar PSF core is saturated. We
present a new technique that can solve these issues by using off-axis satellite
PSFs produced by a periodic amplitude or phase mask conjugated to a pupil
plane. It will be shown that these satellite PSFs track precisely the PSF
position, its Strehl ratio and its intensity and can thus be used to register
and to flux normalize the PSF. A laboratory experiment is also presented to
validate the theory. This approach can be easily implemented in existing
adaptive optics instruments and should be considered for future extreme
adaptive optics coronagraph instruments and in high-contrast imaging space
observatories.


title:
Mid-Infrared Source Multiplicity within Hot Molecular Cores traced by
  Methanol Masers

abstract:
  We present high resolution, mid-infrared images toward three hot molecular
cores signposted by methanol maser emission; G173.49+2.42 (S231, S233IR),
G188.95+0.89 (S252, AFGL-5180) and G192.60-0.05 (S255IR). Each of the cores was
targeted with Michelle on Gemini North using 5 filters from 7.9 to 18.5
microns. We find each contains both large regions of extended emission and
multiple, luminous point sources which, from their extremely red colours
(F[18.5]/F[7.9] >= 3), appear to be embedded young stellar objects. The closest
angular separations of the point sources in the three regions are 0.79, 1.00
and 3.33 arcseconds corresponding to linear separations of 1,700, 1,800 and
6,000AU respectively. The methanol maser emission is found closest to the
brightest MIR point source (within the assumed 1 arcsecond pointing accuracy).
Mass and luminosity estimates for the sources range from 3-22 Msol and
50-40,000 Lsol. Assuming the MIR sources are embedded objects and the observed
gas mass provides the bulk of the reservoir from which the stars formed, it is
difficult to generate the observed distributions for the most massive cluster
members from the gas in the cores using a standard form of the IMF.


title:
A WENO Algorithm for the Radiative Transfer and Ionized Sphere at
  Reionization

abstract:
  We show that the algorithm based on the weighted essentially nonoscillatory
(WENO) scheme with anti-diffusive flux corrections can be used as a solver of
the radiative transfer equations. This algorithm is highly stable and robust
for solving problems with both discontinuities and smooth solution structures.
We test this code with the ionized sphere around point sources. It shows that
the WENO scheme can reveal the discontinuity of the radiative or ionizing
fronts as well as the evolution of photon frequency spectrum with high accuracy
on coarse meshes and for a very wide parameter space. This method would be
useful to study the details of the ionized patch given by individual source in
the epoch of reionization. We demonstrate this method by calculating the
evolution of the ionized sphere around point sources in physical and frequency
spaces. It shows that the profile of the fraction of neutral hydrogen and the
ionized radius are sensitively dependent on the intensity of the source.


title: A Survey for Spectroscopic Binaries Among Very Low-Mass Stars

abstract:
  We report on the results of a survey for radial velocity variability in a
heterogeneous sample of very low-mass stars and brown dwarfs. One
distinguishing characteristic of the survey is its timespan, which allows an
overlap between spectroscopic binaries and those which can be found by high
angular-resolution imaging. We are able to place a new constraint on the total
binary fraction in these objects, which suggests that they are more likely the
result of extending the same processes at work at higher masses into this mass
range, rather than a distinct mode of formation. Our basic result is that there
are $6 \pm 2$ out of 53, or $11^{+0.07}_{-0.04}$% spectroscopic binaries in the
separation range 0-6 AU, nearly as many as resolved binaries. This leads to an
estimate of an upper limit of $26 \pm 10$% for the binary fraction of VLM
objects (it is an upper limit because of the possible overlap between the
spectroscopic and resolved populations). A reasonable estimate for the very
low-mass binary fraction is $20 - 25$%. We consider several possible separation
and frequency distributions, including the same one as found for GK stars, a
compressed version of that, a version of the compressed distribution truncated
at 15 AU, and a theoretical distribution which considers the evaporation of
small-N clusters. We conclude that the latter two bracket the observations,
which may mean that these systems form with intrinsically smaller separations
due to their smaller mass, and then are truncated due to their smaller binding
energy. We do not find support for the ``ejection hypothesis'' as their
dominant mode of formation, particularly in view of the similarity in the total
binary fraction compared with slightly more massive stars, and the difficulty
this mechanism has in producing numerous binary systems.


title: Circumstellar material in the Vega inner system revealed by CHARA/FLUOR

abstract:
  Only a handful of debris disks have been imaged up to now. Due to the need
for high dynamic range and high angular resolution, very little is known about
the inner planetary region, where small amounts of warm dust are expected to be
found. We investigate the close neighbourhood of Vega with the help of infrared
stellar interferometry and estimate the integrated K-band flux originating from
the central 8 AU of the debris disk. We performed precise visibility
measurements at both short (~30 m) and long (~150 m) baselines with the FLUOR
beam-combiner installed at the CHARA Array (Mt Wilson, California) in order to
separately resolve the emissions from the extended debris disk (short
baselines) and from the stellar photosphere (long baselines). After revising
Vega's K-band angular diameter (3.202+/-0.005 mas), we show that a significant
deficit in squared visibility (1.88+/-0.34%) is detected at short baselines
with respect to the best-fit uniform disk stellar model. This deficit can be
either attributed to the presence of a low-mass stellar companion around Vega,
or as the signature of the thermal and scattered emissions from the debris
disk. We show that the presence of a close companion is highly unlikely, as
well as other possible perturbations (stellar morphology, calibration), and
deduce that we have most probably detected the presence of dust in the close
neighbourhood of Vega. The resulting flux ratio between the stellar photosphere
and the debris disk amounts to 1.29+/-0.19% within the FLUOR field-of-view
(~7.8 AU). Finally, we complement our K-band study with archival photometric
and interferometric data in order to evaluate the main physical properties of
the inner dust disk. The inferred properties suggest that the Vega system could
be currently undergoing major dynamical perturbations.


title:
Envelope Expansion with Core Collapse. III. Similarity Isothermal Shocks
  in a Magnetofluid

abstract:
  We explore MHD solutions for envelope expansions with core collapse (EECC)
with isothermal MHD shocks in a quasi-spherical symmetry and outline potential
astrophysical applications of such magnetized shock flows. MHD shock solutions
are classified into three classes according to the downstream characteristics
near the core. Class I solutions are those characterized by free-fall collapses
towards the core downstream of an MHD shock, while Class II solutions are those
characterized by Larson-Penston (LP) type near the core downstream of an MHD
shock. Class III solutions are novel, sharing both features of Class I and II
solutions with the presence of a sufficiently strong magnetic field as a
prerequisite. Various MHD processes may occur within the regime of these
isothermal MHD shock similarity solutions, such as sub-magnetosonic
oscillations, free-fall core collapses, radial contractions and expansions. We
can also construct families of twin MHD shock solutions as well as an
`isothermal MHD shock' separating two magnetofluid regions of two different yet
constant temperatures. The versatile behaviours of such MHD shock solutions may
be utilized to model a wide range of astrophysical problems, including star
formation in magnetized molecular clouds, MHD link between the asymptotic giant
branch phase to the proto-planetary nebula phase with a hot central magnetized
white dwarf, relativistic MHD pulsar winds in supernova remnants, radio
afterglows of soft gamma-ray repeaters and so forth.


title:
Lyman-alpha emission galaxies at a redshift of z = 5.7 in the FORS Deep
  Field

abstract:
  We present the results of a search for Lyman-alpha emission galaxies at z~
5.7 in the FORS Deep Field. The objective of this study is to improve the faint
end of the luminosity function of high-redshift Lyman-alpha emitting galaxies
and to derive properties of intrinsically faint Lyman-alpha emission galaxies
in the young universe. Using FORS2 at the ESO VLT and a set of special
interference filters, we identified candidates for high-redshift Lyman-alpha
galaxies. We then used FORS2 in spectroscopic mode to verify the
identifications and to study their spectral properties. The narrow-band
photometry resulted in the detection of 15 likely Lyman-alpha emission
galaxies. Spectra with an adequate exposure time could be obtained for eight
galaxies. In all these cases the presence of Lyman-alpha emission at z = 5.7
was confirmed spectroscopically. The line fluxes of the 15 candidates range
between 3 and 16 * 10^-21 Wm^-2, which corresponds to star-formation rates not
corrected for dust between 1 and 5 Msun/yr. The luminosity function derived for
our photometrically identified objects extends the published luminosity
functions of intrinsically brighter Lyman-alpha galaxies. With this technique
the study of high-redshift Lyman-alpha emission galaxies can be extended to low
intrinsic luminosities.


title: Relaxation of a 1-D gravitational system

abstract:
  We study the relaxation towards thermodynamical equilibrium of a 1-D
gravitational system. This OSC model shows a series of critical energies
$E_{cn}$ where new equilibria appear and we focus on the homogeneous ($n=0$),
one-peak ($n=\pm 1$) and two-peak ($n=2$) states. Using numerical simulations
we investigate the relaxation to the stable equilibrium $n=\pm 1$ of this
$N-$body system starting from initial conditions defined by equilibria $n=0$
and $n=2$. We find that in a fashion similar to other long-range systems the
relaxation involves a fast violent relaxation phase followed by a slow
collisional phase as the system goes through a series of quasi-stationary
states. Moreover, in cases where this slow second stage leads to a dynamically
unstable configuration (two peaks with a high mass ratio) it is followed by a
new sequence ``violent relaxation/slow collisional relaxation''. We obtain an
analytical estimate of the relaxation time $t_{2\to \pm 1}$ through the mean
escape time of a particle from its potential well in a bistable system. We find
that the diffusion and dissipation coefficients satisfy Einstein's relation and
that the relaxation time scales as $N e^{1/T}$ at low temperature, in agreement
with numerical simulations.


title:
Comment on "Heavy element production in inhomogeneous big bang
  nucleosynthesis"

abstract:
  The work of Matsuura et al. [Phys. Rev. D 72, 123505 (2005);
astro-ph/0507439] claims that heavy nuclei could have been produced in a
combined p- and r-process in very high baryon density regions of an
inhomogeneous big bang. However, they do not account for observational
constraints and previous studies which show that such high baryon density
regions did not significantly contribute to big bang abundances.


title: Casimir Effect confronts Cosmological Constant

abstract:
  It has been speculated that the zero-point energy of the vacuum, regularized
due to the existence of a suitable ultraviolet cut-off scale, could be the
source of the non-vanishing cosmological constant that is driving the present
acceleration of the universe. We show that the presence of such a cut-off can
significantly alter the results for the Casimir force between parallel
conducting plates and even lead to repulsive Casimir force when the plate
separation is smaller than the cut-off scale length. Using the current
experimental data we rule out the possibility that the observed cosmological
constant arises from the zero-point energy which is made finite by a suitable
cut-off. Any such cut-off which is consistent with the observed Casimir effect
will lead to an energy density which is about 10^{12} times larger than the
observed one, if gravity couples to these modes. The implications are
discussed.


title:
Photometric survey of marginally investigated open clusters: I. Basel
  11b, King 14, Czernik 43

abstract:
  To progress in galactic studies based on open clusters, e.g. cluster
formation rate or kinematical properties, one needs to improve the number of
open clusters observed. However, only half of the 1700 known galactic open
clusters have been properly observed so far, making any statistical
investigation insignificant, especially at larger distances from the Sun. We
study marginally investigated or neglected open clusters with Bessell CCD BVR
photometry, whose data were used to fit isochrones to the individual
color-magnitude diagrams. We examined the galactic clusters Basel 11b, King 14
and Czernik 43, the last being observed for the first time to this extent. As
well as a careful comparison to available photometry, their parameters such as
age, interstellar reddening, distance and apparent diameter were determined.
The obtained cluster properties were verified by near infrared 2MASS data. The
three investigated intermediate age clusters are all located in the galactic
disk with distances between 1.8 and 3.0kpc from the Sun.


title: The opaque nascent starburst in NGC 1377: Spitzer SINGS observations

abstract:
  We analyze extensive data on NGC1377 from the Spitzer Infrared Nearby
Galaxies Survey (SINGS). Within the category of nascent starbursts, that we
previously selected by their infrared to radio continuum ratios in large excess
of the average and their hot dust, NGC1377 has the largest infrared excess yet
measured. Optical imaging reveals a morphological distortion suggestive of a
recent accretion event. Infrared spectroscopy reveals a compact and opaque
source dominated by a hot, self-absorbed continuum (tau ~ 20 in the 10 micron
silicate band). We provide physical evidence against non-stellar activity being
the heating source. HII regions are detected through the single [NeII] line,
probing <1% of the ionizing radiation. Not only is the optical depth very high,
but >85% of ionizing photons are suppressed by dust. The only other detected
emission features are molecular hydrogen lines, arguably excited mainly by
shocks, besides photodissociation regions, and weak aromatic bands. The new
observations support our interpretation in terms of an extremely young
starburst (<1 Myr). More generally, galaxies deficient in radio synchrotron are
likely observed within a few Myr of the onset of a starburst and after a long
quiescence, prior to the replenishment of the ISM with cosmic rays. The similar
infrared-radio properties of NGC1377 and some infrared-luminous galaxies
suggest that NGC1377 constitutes an archetype to better understand starburst
evolution. Although rare locally because observed in a brief evolutionary
stage, nascent starbursts may represent a non-negligible fraction of
merger-induced starbursts dominating deep infrared counts. Since they differ
dramatically from usual starburst templates, they bear important consequences
for the interpretation of deep surveys.


title:
A Chemical Abundance Study of three RHB and two RGB stars in NGC6637
  (M69)

abstract:
  We present a detailed chemical abundance study of three red horizontal branch
and two red giant branch stars in the metal-rich globular cluster NGC 6637
(M69). The value of [Fe/H] derived from LTE calculations is $-$0.77 $\pm$ 0.02
dex. We also discuss the anticorrelation between oxygen and sodium abundances
in the program stars and compare the [Si/Ti] ratio of NGC 6637 with those of
other globular clusters.


title: Quasar acceleration by a one-side jet and asymmetric radiation

abstract:
  A quasar (as well as an active galactic nucleus) which emits a one-side jet
(or which is an anisotropic emitter of particles and quanta) can be accelerated
and leave its host galaxy.


title:
Oxygen abundance variations in the system of the two blue compact dwarf
  galaxies SBS 0335-052E and SBS 0335-052W

abstract:
  We present 3.6m ESO telescope spectroscopic observations of the system of the
two blue compact dwarf galaxies SBS 0335-052W and SBS 0335-052E. The oxygen
abundance in SBS 0335-052W is 12 + log O/H = 7.13 +/- 0.08, confirming that
this galaxy is the most metal-deficient emission-line galaxy known. We find
that the oxygen abundance in SBS 0335-052E varies from region to region in the
range from 7.20 to 7.31, suggesting the presence of an abundance gradient over
a spatial scale of 1 kpc. Signatures of early carbon-type Wolf-Rayet stars are
detected in cluster 3 of SBS 0335-052E, corresponding to the emission of three
to eighteen WC4 stars, depending on the adopted luminosity of a single WC4 star
in the CIV 4658 emission line.


title: TNG publications 1989-2005

abstract:
  This document lists a set of (refereed and unrefereed) scientific
publications based on data taken with the instruments of the Italian Telescopio
Nazionale Galileo (TNG, mainly from the year 2000 onward) and the technical
papers describing the development of the TNG project from the "phase A" (late
'80s) until the end of year 2005. The collection is compiled by searching for
publications on the internet. In particular, the search engines of the NASA
Astrophysics Data System and Google Scholar are used. This work represents the
first attempt to probe the scientific production of the TNG and will be updated
regularly from year to year. Comments and suggestions are welcome.


title:
Confronting Dark Energy Models with Astrophysical Data: Non-Equilibrium
  vs. Conventional Cosmologies

abstract:
  We discuss fits of cosmological dark energy models to the available data on
high-redshift supernovae. We consider a conventional model with Cold Dark
Matter and a cosmological constant (LambdaCDM), a model invoking super-horizon
perturbations (SHCDM) and models based on Liouville strings in which dark
energy is provided by a rolling dilaton field (Q-cosmology). We show that a
complete treatment of Q-cosmology requires a careful discussion of
non-equilibrium situations (off-shell effects). The two main high-redshift
supernova data sets give compatible constraints on LambdaCDM and the other
models. We recover the well-known result that LambdaCDM fits very well the
combined supernova data sets, as does the super-horizon model. We discuss the
model-dependent off-shell corrections to the Q-cosmology model that are
relevant to the supernova data, and show that this model fits the data equally
well. This analysis could be extended to other aspects of cosmological
phenomenology, in particular to the CMB and Baryon Acoustic Oscillations, which
have so far been treated using on-shell models.


title:
Radio emission of highly inclined cosmic ray air showers measured with
  LOPES

abstract:
  LOPES (LOFAR Prototype Station) is an array of dipole antennas used for
detection of radio emission from air showers. It is co-located and triggered by
the KASCADE (Karlsruhe Shower Core and Array Detector) experiment, which also
provides informations about air shower properties. Even though neither LOPES
nor KASCADE are completely optimized for the detection of highly inclined
events, a significant number of showers with zenith angle larger than 50$^o$
have been detected in the radio domain, and many with very high field
strengths. Investigation of inclined showers can give deeper insight into the
nature of primary particles that initiate showers and also into the possibility
that some of detected showers are triggered by neutrinos. In this paper, we
show the example of such an event and present some of the characteristics of
highly inclined showers detected by LOPES.


title:
Accretion column structure of magnetic cataclysmic variables from X-ray
  spectroscopy

abstract:
  Using Chandra HETG data we present light curves for individual spectral lines
of Mg XI and Mg XII for EX Hydrae, an intermediate-polar type cataclysmic
variable. The Mg XI light curve, folded on the white dwarf spin period, shows
two spikes that are not seen in the Mg XII or broad-band light curves.
Occultation of the accretion column by the body of the white dwarf would
produce such spikes for an angle between the rotation axis and the accretion
columns of alpha = 18 degrees and a height of the Mg XI emission above the
white dwarf surface of < 0.0004 white dwarf radii or < 4 km. The absence of
spikes in the Mg XII and broad-band light curves could then be explained if the
bulk of its emission forms at much larger height, > 0.004 white dwarf radii or
> 40 km, above the white dwarf surface, although this is not consistent with
the predictions of the standard Aizu model of the accretion column.


title: AD Mensae: a dwarf nova in the period gap

abstract:
  AD Men was classified as a probable long-period dwarf nova based on its
long-term variability. Recent spectroscopic data instead suggested a
short-period system. With the here presented observations we aim at clarifying
its nature. Time--resolved photometry and spectroscopy has been used to get
information on the orbital period of this system. The light curve shows the
typical flickering and a clear hump--like periodic modulation with an average
amplitude of 0.3mag and a period of P=2.20(02)h. The radial velocity
measurements of the Halpha emission line confirm this value as the orbital
period. AD Men is thus located at the lower end of, but clearly inside, the gap
of the period distribution of cataclysmic variables, making it one of only 11
dwarf novae in this important period range.


title: Mapping Global Star Formation in the Interacting Galaxy Pair ARP 32

abstract:
  A multi-wavelength set of photometric data including UV (GALEX), optical,
near-IR, infrared (Spitzer) and radio (VLA 20cm) images and spectroscopic
observations are used to map the dust-obscured and unobscured star formation in
the galaxy pair ARP 32. The system consists of an actively star-forming galaxy
and another one with depressed star formation. The most active galaxy has
disrupted morphology and different sites of star formation. Spectroscopic data
show hints of nuclear activity in its core, intense star formation in limited
regions of the galaxy as well as an underlying population of stars witnessing a
past episode of star formation. Current star formation rates are estimated from
UV and bolometric IR luminosities.


title:
A Comprehensive Search for Gamma-Ray Lines in the First Year of Data
  from the INTEGRAL Spectrometer

abstract:
  We have carried out an extensive search for gamma-ray lines in the first year
of public data from the Spectrometer (SPI) on the INTEGRAL mission. INTEGRAL
has spent a large fraction of its observing time in the Galactic Plane with
particular concentration in the Galactic Center (GC) region (~ 3 Msec in the
first year). Hence the most sensitive search regions are in the Galactic Plane
and Center. The phase space of the search spans the energy range 20-8000 keV
and line widths from 0-1000 keV (FWHM). It includes both diffuse and point-like
emission. We have searched for variable emission on time scales down to ~ 1000
sec. Diffuse emission has been searched for on a range of different spatial
scales from ~ 20 deg (the approximate field-of-view of the spectrometer) up to
the entire Galactic Plane. Our search procedures were verified by the recovery
of the known gamma-ray lines at 511 keV and 1809 keV at the appropriate
intensities and significances. We find no evidence for any previously unknown
gamma-ray lines. The upper limits range from a few x 10^-5 cm^-2 s^-1 to a few
x 10^-2 cm^-2 s^-1 depending on line width, energy and exposure; regions of
strong instrumental background lines were excluded from the search. Comparison
is made between our results and various prior predictions of astrophysical
lines.


title: Gravitational Microlensing

abstract:
  This review forms the microlensing part of the 33rd Saas-Fee Advanced Course
"Gravitational Lensing: Strong, Weak & Micro'', which was held in April 2003 in
Les Diablerets. It contains an introduction to the lensing effects of single
and binary stars and it summarizes the state-of-the-art of microlensing
observations and prospects at the time of the meeting. Stellar microlensing as
well as quasar microlensing are covered.


title: Unveiling Hidden Patterns in CMB Anisotropy Maps

abstract:
  Bianchi VII_h models have been recently proposed to explain potential
anomalies in the CMB anisotropy as observed by WMAP. We investigate the
violation of statistical isotropy due to an embedded Bianchi VII_h templates in
the CMB anisotropy maps to determine whether the existence of a hidden Bianchi
template in the WMAP data is consistent with the previous null detection of the
bipolar power spectrum in the WMAP first year maps. We argue that although
correcting the WMAP maps for the Bianchi template may explain some features in
the WMAP data it may cause other anomalies such as preferred directions leading
to detectable levels of violation of statistical isotropy in the Bianchi
corrected maps. We compute the bipolar power spectrum for the low density
Bianchi VII_h models embedded in the background CMB anisotropy maps with the
power spectrum that have been shown in recent literature to best fit the first
year WMAP data. By examining statistical isotropy of these maps, we put a limit
of {\sigma/H}_0 < 2.77E-10 (99% CL) on the shear parameter in Bianchi VII_h
models.


title: Biased Cosmology: Pivots, Parameters, and Figures of Merit

abstract:
  In the quest for precision cosmology, one must ensure that the cosmology is
accurate as well. We discuss figures of merit for determining from observations
whether the dark energy is a cosmological constant or dynamical, with special
attention to the best determined equation of state value, at the ``pivot'' or
decorrelation redshift. We show this is not necessarily the best lever on
testing consistency with the cosmological constant, and moreover is subject to
bias. The standard parametrization of w(a)=w_0+w_a(1-a) by contrast is quite
robust, as tested by extensions to higher order parametrizations and modified
gravity. Combination of complementary probes gives strong immunization against
inaccurate, but precise, cosmology.


title:
Supermassive Black Hole Merger Rates: Uncertainties from Halo Merger
  Theory

abstract:
  The merger of two supermassive black holes is expected to produce a
gravitational-wave signal detectable by the satellite LISA. The rate of
supermassive-black-hole mergers is intimately connected to the halo merger
rate, and the extended Press-Schechter formalism is often employed when
calculating the rate at which these events will be observed by LISA. This
merger theory is flawed and provides two rates for the merging of the same pair
of haloes. We show that the two predictions for the LISA
supermassive-black-hole-merger event rate from extended Press-Schechter merger
theory are nearly equal because mergers between haloes of similar masses
dominate the event rate. An alternative merger rate may be obtained by
inverting the Smoluchowski coagulation equation to find the merger rate that
preserves the Press-Schechter halo abundance, but these rates are only
available for power-law power spectra. We compare the LISA event rates derived
from the extended Press-Schechter merger formalism to those derived from the
merger rates obtained from the coagulation equation and find that the extended
Press-Schechter LISA event rates are thirty percent higher for a power spectrum
spectral index that approximates the full Lambda-CDM result of the extended
Press-Schechter theory.


title: Information content in the halo-model dark-matter power spectrum

abstract:
  Using the halo model, we investigate the cosmological Fisher information in
the non-linear dark-matter power spectrum about the initial amplitude of linear
power. We find that there is little information on `translinear' scales (where
the one- and two-halo terms are both significant) beyond what is on linear
scales, but that additional information is present on small scales, where the
one-halo term dominates. This behavior agrees with the surprising results that
Rimes & Hamilton (2005, 2006) found using N-body simulations. We argue that the
translinear plateau in cumulative information arises largely from fluctuations
in the numbers of large haloes in a finite volume. This implies that more
information could be extracted on non-linear scales if the masses of the
largest haloes in a survey are known.


title:
Discovery of magnetic fields in the beta Cephei star xi^1 CMa and in
  several Slowly Pulsating B stars

abstract:
  We present the results of a magnetic survey of a sample of eight beta Cephei
stars and 26 Slowly Pulsating B stars with FORS1 at the VLT. A weak mean
longitudinal magnetic field of the order of a few hundred Gauss is detected in
the beta Cephei star xi^1 CMa and in 13 SPB stars. The star xi^1 CMa becomes
the third magnetic star among the beta Cephei stars. Before our study, the star
zeta Cas was the only known magnetic SPB star. All magnetic SPB stars for which
we gathered several magnetic field measurements show a field that varies in
time. We do not find a relation between the evolution of the magnetic field
with stellar age in our small sample. Our observations imply that beta Cephei
stars and SPBs can no longer be considered as classes of non-magnetic
pulsators, but the effect of the fields on the oscillation properties remains
to be studied.


title:
Millimagnitude Optical Photometry for the Transiting Planetary Candidate
  OGLE-TR-109

abstract:
  We present precise V-band photometry for the low-amplitude transit candidate
star OGLE-TR-109. This is an extreme case among the transiting candidates found
by the OGLE group because of the early spectral type of the star (F0V), of the
low transit amplitude (A_I=0.008 mag), and of the very short period (P=0.58909
days) of the orbiting companion. Using difference image photometry, we are able
to achieve millimagnitude errors in the individual data points. One transit of
this star is well defined in our light curve. This confirms the OGLE detection
and rules out the possibility of a false positive. The measurement of this
transit allows to refine the transit amplitude (A_V=0.006 +/- 0.001 mag), and
the ephemerides for this interesting system, as well as the radius of the
possible orbiting companion (R_P=0.90 +/- 0.09 ~R_J), and the inclination of
the orbit (i=77 +/- 5 deg). Two other transits observed at lower S/N confirm
the period of this system measured by OGLE. There is no evidence for a blend of
the F-type main sequence star with a redder eclipsing binary, or for secondary
transits in the present observations. The absence of ellipsoidal modulation in
the light curve of the primary rules out a low mass star companion or brown
dwarf with M>14 +/- 8 M_J. The remaining possibilities for OGLE-TR-109 are a
blend between the F-type star and a binary with a bluer primary star, or a new
transiting extrasolar planet.


title:
Toward 1% Photometry: End-to-end Calibration of Astronomical Telescopes
  and Detectors

abstract:
  We review the systematic uncertainties that have plagued attempts to obtain
high precision and high accuracy from ground-based photometric measurements
using CCDs. We identify two main challenges in breaking through the 1%
precision barrier: 1) fully characterizing atmospheric transmission, along the
instrument's line of sight, and 2) properly identifying, measuring and removing
instrumental artifacts. We discuss approximations and limitations inherent in
the present methodology, and we estimate their contributions to systematic
photometric uncertainties. We propose an alternative conceptual scheme for the
relative calibration of astronomical apparatus: the availability of calibrated
detectors whose relative spectral sensitivity is known to better than one part
in $10^3$ opens up the possibility of in situ relative throughput measurements,
normalized to a precision calibrated detector, using a stable but uncalibrated
narrowband light source. An implementation scheme is outlined, which exploits
the availability of tunable lasers to map out the relative wavelength response
of an imaging system, using a flatfield screen and a calibrated reference
photodiode. The merits and limitations of this scheme are discussed. In tandem
with careful measurements of atmospheric transmission, this approach could
potentially lead to reliable ground-based photometry with fractional
uncertainties below the percent level.


title: Dynamical Masses in Luminous Infrared Galaxies

abstract:
  We have studied the dynamics and masses of a sample of ten nearby luminous
and ultraluminous infrared galaxies (LIRGS and ULIRGs), using 2.3 micron CO
absorption line spectroscopy and near-infrared H- and Ks-band imaging. By
combining velocity dispersions derived from the spectroscopy, disk
scale-lengths obtained from the imaging, and a set of likely model density
profiles, we calculate dynamical masses for each LIRG. For the majority of the
sample, it is difficult to reconcile our mass estimates with the large amounts
of gas derived from millimeter observations and from a standard conversion
between CO emission and H_2 mass. Our results imply that LIRGs do not have huge
amounts of molecular gas (10^10-10^11 Msolar) at their centers, and support
previous indications that the standard conversion of CO to H_2 probably
overestimates the gas masses and cannot be used in these environments. This in
turn suggests much more modest levels of extinction in the near-infrared for
LIRGs than previously predicted (A_V~10-20 versus A_V~100-1000). The lower gas
mass estimates indicated by our observations imply that the star formation
efficiency in these systems is very high and is triggered by cloud-cloud
collisions, shocks, and winds rather than by gravitational instabilities in
circumnuclear gas disks.


title:
Breaking the scale invariance of the primordial spectrum or not: the new
  WMAP data

abstract:
  It seems that new WMAP data requires a fit with a primordial spectrum
containig small negative tilt index in addition to the featureless
Harrison-Zeldovich- Peebles spectrum thus implying a broken scale invariance.
We show that the data could be otherwise interpreted by a scale invariant
primordial spectrum with the scale non-invariant evolution of density contrast
using the Press-Schechter formalism. The estimate of the acceleration
parameter, as a source of the inhomogeneity of spacetime, is made by searching
for the minima of the deviation measure defined by the Press-Schechter mass
functions for this interpretation compared to the assumptions implicit in the
WMAP fit.


title: The Parkes Pulsar Timing Array

abstract:
  Given sufficient sensitivity, pulsar timing observations can make a direct
detection of gravitational waves passing over the Earth. Pulsar timing is most
sensitive to gravitational waves with frequencies in the nanoHertz region, with
the most likely astronomical sources being binary super-massive black holes in
galaxy cores. The Parkes Pulsar Timing Array project uses the Parkes 64-m radio
telescope to make precision timing observations of a sample of about 20
millisecond pulsars with a principal goal of making a direct detection of
gravitational waves. Observations commenced about one year ago and so far
sub-microsecond timing residuals have been achieved for more than half of these
pulsars. New receiver and software systems are being developed with the aim of
reducing these residuals to the level believed necessary for a positive
detection of gravitational waves.


title:
Clusters of Galaxies at 1 < z < 2 : The Spitzer Adaptation of the
  Red-Sequence Cluster Survey

abstract:
  As the densest galaxy environments in the universe, clusters are vital to our
understanding of the role that environment plays in galaxy formation and
evolution. Unfortunately, the evolution of high-redshift cluster galaxies is
poorly understood because of the ``cluster desert'' that exists at 1 < z < 2.
The SpARCS collaboration is currently carrying out a 1-passband (z') imaging
survey which, when combined with the pre-existing 50 square degree 3.6 micron
Spitzer SWIRE Legacy Survey data, will efficiently detect hundreds of clusters
in the cluster desert using an infrared application of the well-proven cluster
red-sequence technique. We have already tested this 1-color (z' - [3.6])
approach using a 6 square degree ``pilot patch'' and shown it to be extremely
successful at detecting clusters at 1 < z < 2. The clusters discovered in this
project will be the first large sample of ``nascent'' galaxy clusters which
connect the star-forming proto-cluster regions at z > 2 to the quiescent
population at z < 1. The existing seven-passband Spitzer data (3.6, 4.5, 5.8,
8.0, 24, 70, 160 micron) will allow us to make the first measurements of the
evolution of the cluster red-sequence, IR luminosity function, and the mid-IR
dust-obscured star-formation rate for 1 < z < 2 clusters.


title: The blue stragglers formed via mass transfer in old open clusters

abstract:
  In this paper, we present the simulations for the primordial blue stragglers
in the old open cluster M67 based on detailed modelling of the evolutionary
processes. The principal aim is to discuss the contribution of mass transfer
between the components of close binaries to the blue straggler population in
M67. First, we followed the evolution of a binary of 1.4M$_\odot$+0.9M$_\odot$.
The synthetic evolutionary track of the binary system revealed that a
primordial blue straggler had a long lifetime in the observed blue straggler
region of color-magnitude diagram. Second, a grid of models for close binary
systems experiencing mass exchange were computed from 1Gyr to 6Gyr in order to
account for primordial blue-straggler formation in a time sequence. Based on
such a grid, Monte-Carlo simulations were applied for the old open cluster M67.
Adopting appropriate orbital parameters, 4 primordial blue stragglers were
predicted by our simulations. This was consistent with the observational fact
that only a few blue stragglers in M67 were binaries with short orbital
periods. An upper boundary of the primordial blue stragglers in the
color-magnitude diagram (CMD) was defined and could be used to distinguish blue
stragglers that were not formed via mass exchange. Using the grid of binary
models, the orbital periods of the primordial BSs could be predicted. Compared
with the observations, it is clear that the mechanism discussed in this work
alone cannot fully predict the blue straggler population in M67. There must be
several other processes also involved in the formation of the observed blue
stragglers in M67.


title:
Host Galaxies of Hard X-ray Selected Type-2 Active Galactic Nuclei at
  Intermediate Redshifts

abstract:
  We study properties of the host galaxies of 15 hard X-ray selected type-2
active galactic nuclei (AGNs) at intermediate redshifts (0.05$<z<$0.6) detected
in $ASCA$ surveys. The absorption corrected hard X-ray luminosities $L_{\rm
2-10 keV}$ range from 10$^{42}$ erg s$^{-1}$ to $10^{45}$ erg s$^{-1}$. We took
the $R$-band image of these AGNs with the University of Hawaii 2.2 m telescope.
Thanks to the intrinsic obscuration of nuclear light, we can decompose the
galaxies with a spheroid component and a disk component. The resulting spheroid
luminosities correlate with $L_{\rm 2-10 keV}$; higher (lower) X-ray luminosity
AGNs tend to reside in luminous (less luminous) spheroids. It is also found
that the hosts of luminous AGNs show a large spheroid-to-disk luminosity ratio
($\sim$1), while those of less luminous AGNs spread between 0 and 1. The
correlation between $L_{\rm 2-10keV}$ and spheroid luminosity indicates that
the relation between mass of a supermassive black hole (SMBH) and spheroid
luminosity (BS-relation) at the intermediate redshifts. The BS-relation agrees
with that in the local universe if the Eddington ratio of 0.24 is adopted,
which is a mean value determined from our $ASCA$ type-1 AGN sample at similar
redshifts through the broad-line width and continuum luminosity. The present
study demonstrates the effectiveness of using type-2 AGNs at high redshifts to
study their host properties.


title: Quantum noise and large-scale cosmic microwave background anisotropy

abstract:
  We propose a new source for the cosmological density perturbation which is
passive fluctuations of the inflaton driven dynamically by a colored quantum
noise as a result of its coupling to other massive quantum fields. The created
fluctuations grow with time during inflation before horizon-crossing. However,
the larger-scale modes cross out the horizon earlier, thus resulting in a
suppression of their density perturbation as compared with those on small
scales. By using current observed CMB data to constrain the parameters
introudced, we find that a significant contribution from the noise-driven
perturbation to the density perturbation is still allowed. It in turn gives
rise to a suppression of the large-scale CMB anisotropy that may be relevant to
the observed low quadrupole in the WMAP CMB anisotropy data. We also briefly
discuss the implications to the energy scale of inflation and the spectral
index and non-Gaussianity of the density perturbation.


title:
The properties of the "standard" type Ic supernova 1994I from spectral
  models

abstract:
  The properties of the type Ic supernova SN 1994I are re-investigated. This
object is often referred to as a "standard SN Ic" although it exhibited an
extremely fast light curve and unusually blue early-time spectra. In addition,
the observations were affected by significant dust extinction. A series of
spectral models are computed based on the explosion model CO21 (Iwamoto et al.
1994) using a Monte Carlo transport spectral synthesis code. Overall the
density structure and abundances of the explosion model are able to reproduce
the photospheric spectra well. Reddening is estimated to be E(B-V)=0.30 mag, a
lower value than previously proposed. A model of the nebular spectrum of SN
1994I points toward a slightly larger ejecta mass than that of CO21. The
photospheric spectra show a large abundance of iron-group elements at early
epochs, indicating that mixing within the ejecta must have been significant. We
present an improved light curve model which also requires the presence of 56Ni
in the outer layers of the ejecta.


title: McScatter: a Simple Three-Body Scattering Package with Stellar Evolution

abstract:
  We describe a simple computer package which illustrates a method of combining
stellar dynamics with stellar evolution. Though the method is intended for
elaborate applications (especially the dynamical evolution of rich star
clusters) it is illustrated here in the context of three-body scattering, i.e.
interactions between a binary star and a field of single stars. We describe the
interface between the dynamics and the two independent packages which describe
the internal evolution of single stars and binaries. We also give an example
application, and introduce a stand alone utility for the visual presentation of
simulation results.


title: SPH Simulations with Reconfigurable Hardware Accelerator

abstract:
  We present a novel approach to accelerate astrophysical hydrodynamical
simulations. In astrophysical many-body simulations, GRAPE (GRAvity piPE)
system has been widely used by many researchers. However, in the GRAPE systems,
its function is completely fixed because specially developed LSI is used as a
computing engine. Instead of using such LSI, we are developing a special
purpose computing system using Field Programmable Gate Array (FPGA) chips as
the computing engine. Together with our developed programming system, we have
implemented computing pipelines for the Smoothed Particle Hydrodynamics (SPH)
method on our PROGRAPE-3 system. The SPH pipelines running on PROGRAPE-3 system
have the peak speed of 85 GFLOPS and in a realistic setup, the SPH calculation
using one PROGRAPE-3 board is 5-10 times faster than the calculation on the
host computer. Our results clearly shows for the first time that we can
accelerate the speed of the SPH simulations of a simple astrophysical phenomena
using considerable computing power offered by the hardware.


title: Extinction and metal column density of HI regions up to redshift z~2

abstract:
  We used the photometric database of the Sloan Digital Sky Survey (SDSS) to
estimate the reddening of 13 SDSS quasars selected on the basis of the presence
of zinc absorption lines in an intervening Damped Ly alpha (DLA) system. In 5
of these quasars the reddening is detected at ~2 sigma confidence level in two
independent color indices of the SDSS ugriz photometric system. A detailed
analysis of the data supports an origin of the reddening in the intervening
absorbers. We used these rare measurements of extinction in DLA systems to
probe the relation between extinction and metal column density in the interval
of absorption redshift 0.7 </~ z </~ 2.0. We find that the mean extinction in
the V band per atom of iron in the dust is remarkably similar to that found in
interstellar clouds of the Milky Way. This result lends support to previous
estimates of the dust obscuration effect in DLA systems based on a Milky Way
extinction/metal column density relation. We propose a simple mechanism, based
on dust grain destruction/accretion properties, which may explain the
approximate constancy of the extinction per atom of iron in the dust.


title:
The nucleosynthesis of Al26 and Fe60 in solar metallicity stars
  extending in mass from 11 to 120 Msun: the hydrostatic and explosive
  contributions

abstract:
  We present the \nuk{Al}{26} and \nuk{Fe}{60} yields produced by a generation
of solar metallicity stars ranging in mass between 11 and 120\msun. We discuss
the production sites of these $\gamma$ ray emitters and quantify the relative
contributions of the various components. More specifically we provide the
separate contribution of the wind, the C convective shell and the explosive
Ne/C burning to the total \nuk{Al}{26} yield per each stellar model in our
grid. We provide the contributions of the He convective shell, the C convective
shell and the explosive Ne/C burning to the \nuk{Fe}{60} yield as well. From
these computations we conclude that, at variance with current beliefs,
\nuk{Al}{26} is mainly produced by the explosive C/Ne burning over most of the
mass interval presently analyzed while \nuk{Fe}{60} is mainly produced by the C
convective shell and the He convective shell.


title: The Non-Gaussianity of Racetrack Inflation Models

abstract:
  In this paper, we use the result in [7] to calculate the non-Gaussianity of
the racetrack models in [3, 5]. The two models give different non-
Gaussianities. Both of them are reasonable.


title:
Interaction of massive black hole binaries with their stellar
  environment: I. Ejection of hypervelocity stars

abstract:
  We use full three-body scattering experiments to study the ejection of
hypervelocity stars (HVSs) by massive black hole binaries (MBHBs) at the center
of galaxies. Ambient stars drawn from a Maxwellian distribution unbound to the
binary are expelled by the gravitational slingshot. Accurate measurements of
thermally averaged hardening, mass ejection, and eccentricity growth rates (H,
J, and K) for MBHBs in a fixed stellar background are obtained by numerical
orbit integration from initial conditions determined by Monte Carlo techniques.
Three-body interactions create a subpopulation of HVSs on nearly radial,
corotating orbits, with a spatial distribution that is initially highly
flattened in the inspiral plane of the MBHB, but becomes more isotropic with
decreasing binary separation. The degree of anisotropy is smaller for unequal
mass binaries and larger for stars with higher kick velocities. Eccentric MBHBs
produce a more prominent tail of high-velocity stars and break planar symmetry,
ejecting HVSs along a broad jet perpendicular to the semimajor axis. The jet
two-sidedness decreases with increasing binary mass ratio, while the jet
opening-angle increases with decreasing kick velocity and orbital separation.
The detection of a numerous population of HVSs in the halo of the Milky Way by
the next generation of large astrometric surveys like GAIA may provide a unique
signature of the history, nature, and environment of the MBH at the Galactic
center.


title: Earth matter effects in supernova neutrinos: Optimal detector locations

abstract:
  A model-independent experimental signature for flavor oscillations in the
neutrino signal from the next Galactic supernova (SN) would be the observation
of Earth matter effects. We calculate the probability for observing a Galactic
SN shadowed by the Earth as a function of the detector's geographic latitude.
This probability depends only mildly on details of the Galactic SN
distribution. A location at the North Pole would be optimal with a shadowing
probability of about 60%, but a far-northern location such as Pyhasalmi in
Finland, the proposed site for a large-volume scintillator detector, is almost
equivalent (58%). We also consider several pairs of detector locations and
calculate the probability that only one of them is shadowed, allowing a
comparison between a shadowed and a direct signal. For the South Pole combined
with Kamioka this probability is almost 75%, for the South Pole combined with
Pyhasalmi it is almost 90%. One particular scenario consists of a large-volume
scintillator detector located in Pyhasalmi to measure the geo-neutrino flux in
a continental location and another such detector in Hawaii to measure it in an
oceanic location. The probability that only one of them is shadowed exceeds 50%
whereas the probability that at least one is shadowed is about 80%. We provide
an online tool to calculate different shadowing probabilities for the one- and
two-detector cases.


title: The flow field in the sunspot canopy

abstract:
  We investigate the flow field in the sunspot canopy using simultaneous Stokes
vector spectropolarimetry of three sunspots ($\theta$ = 27, 50, 75 deg) and
their surroundings in visible (630.15 and 630.25 nm) and near infrared (1564.8
and 1565.2 nm) neutral iron lines.} {To calibrate the Doppler shifts, we
compare an absolute velocity calibration using the telluric $O_2$-line at
630.20 nm and a relative velocity calibration using the Doppler shift of Stokes
V profiles in the umbra under the assumption that the umbra is at rest. Both
methods yield the same result within the calibration uncertainties (~150 m/s).
We study the radial dependence of Stokes V profiles in the directions of disk
center and limb side. Maps of Stokes V profile shifts, polarity, amplitude
asymmetry, field strength and magnetic field azimuth provide strong evidence
for the presence of a magnetic canopy and for the existence of a radial outflow
in the canopy. Our findings indicate that the Evershed flow does not cease
abruptly at the white-light spot boundary, but that at least a part of the
penumbral Evershed flow continues into the magnetic canopy.


title:
Microlensing in phase space I: Continuous propagation of variability
  moments

abstract:
  A method to calculate the statistical properties of microlensing light curves
is developed. The approach follows works by Deguchi & Watson, Seitz & Schneider
and Neindorf, attempting to clarify the ideas involved and techniques used in
the calculations. The method is then modified to include scattering by multiple
lensing planes along the line of sight and transition to a continuous limit of
this treatment for average quantities is performed leading to a Fokker-Planck
type equation. The equation is solved for a particular model of the random star
field and microlensing effect on the flux temporal variability is extracted.
Applications in astrophysically relevant situations are discussed.


title: Investigating halo substructures with annual modulation signature

abstract:
  Galaxy hierarchical formation theories, numerical simulations, the discovery
of the Sagittarius Dwarf Elliptical Galaxy (SagDEG) in 1994 and more recent
investigations suggest that the dark halo of the Milky Way can have a rich
phenomenology containing non thermalized substructures. In the present
preliminary study, we investigate the case of the SagDEG (the best known
satellite galaxy in the Milky Way crossing the solar neighbourhood) analyzing
the consequences of its dark matter stream contribution to the galactic halo on
the basis of the DAMA/NaI annual modulation data. The present analysis is
restricted to some WIMP candidates and to some of the astrophysical, nuclear
and particle Physics scenarios. Other candidates such as e.g. the light bosonic
ones, we discussed elsewhere, and other non thermalized substructures are not
yet addressed here.


title: Black Holes: from Speculations to Observations

abstract:
  This paper provides a brief review of the history of our understanding and
knowledge of black holes. Starting with early speculations on ``dark stars'' I
discuss the Schwarzschild "black hole" solution to Einstein's field equations
and the development of its interpretation from "physically meaningless" to
describing the perhaps most exotic and yet "most perfect" macroscopic object in
the universe. I describe different astrophysical black hole populations and
discuss some of their observational evidence. Finally I close by speculating
about future observations of black holes with the new generation of
gravitational wave detectors.


title:
A high-significance detection of non-Gaussianity in the WMAP 3-year data
  using directional spherical wavelets

abstract:
  We repeat the directional spherical real Morlet wavelet analysis used to
detect non-Gaussianity in the WMAP 1-year data (McEwen et al. 2005a), on the
WMAP 3-year data. The non-Gaussian signal previously detected is indeed present
in the 3-year data, although the significance of the detection is reduced.
Using our most conservative method for constructing significance measures, we
find the significance of the detection of non-Gaussianity drops from
98.3+/-0.4% to 94.9+/-0.7%; the significance drops from 99.3+/-0.3% to
97.2+/-0.5% using a method based on the $\chi^2$ statistic. The wavelet
analysis allows us to localise most likely sources of non-Gaussianity on the
sky. We detect very similar localised regions in the WMAP 1-year and 3-year
data, although the regions extracted appear more pronounced in the 3-year data.
When all localised regions are excluded from the analysis the 3-year data is
consistent with Gaussianity.


title:
Optical polarimetry and infrared photometry of two AM Her binaries: 1RXS
  J161008.0+035222 and 1RXS J231603.9-052713

abstract:
  We present the first optical circular and linear polarization measurements of
two polar candidates from ROSAT: 1RXS J161008.0+035222 and 1RXS
J231603.9-052713. We also present H band near-infrared photometry of the last
object. The presence of strong circular polarization confirms them as AM Her
systems. 1RXS J231603.9-052713 was observed in two different brightness states.
The orbital phase dependence of the flux and polarization of 1RXS
J161008.0+035222 is reasonably fitted with a simple model in which the binary
is observed at a small inclination and the magnetic field axis is almost
parallel to the white-dwarf rotation axis resulting in the accretion column
axis being seen from top during the whole orbital revolution. The magnetic
field is probably in the 10 to 20 MG range. The circular polarization of 1RXS
J231603.9-052713 is complex and highly variable. The light-curves of that
object have been fitted using a model which includes the white-dwarf, a heated
secondary and a point-like accretion region. The secondary emission contributes
significantly even in optical wavelengths. This model also reproduces the main
features of the optical polarization of 1RXS J231603.9-052713. We estimate the
main parameters of the binary, of the accretion region and the distance to the
system. However, a more precise interpretation of this system should take in
account an extended and inhomogeneous accreting region as well as non-radial
accretion.


title: Thermonuclear Ignition of Dark Galaxies

abstract:
  Dark matter is thought to be at least an order of magnitude more abundant
than luminous matter in the Universe, but there has yet to be an unambiguous
identification of a wholly dark, galactic-scale structure. There is, however,
increasing evidence that VIRGOHI 21 may be a dark galaxy. If VIRGOHI 21 turns
out to be composed of dark stars, having approximately the same mass of stars
found in luminous galaxies, it will pose an enigma within the framework of
current astrophysical models, but will provide strong support for my concept,
published in 1994 in the Proceedings of the Royal Society of London, of the
thermonuclear ignition of stars by nuclear fission, and the corollary,
non-ignition of stars. The possibility of galactic thermonuclear ignition is
discussed from that framework and leads to my suggestion that the distribution
of luminous stars in a galaxy may simply be a reflection of the galactic
distribution of the heavy elements.


title: AGN Outflows and the Matter Power Spectrum

abstract:
  We have investigated the effects of AGN outflows on the amplitude of the
matter power spectrum in a simple model of spherically symmetric outflows
around realistically clustered AGN population. We find that two competing
effects influence the matter power spectrum in two opposite directions. First,
AGN outflows move baryons from high to low density regions, decreasing the
amplitude of the matter power spectrum by up to 20%. Second, high clustering of
the AGN transfers the power from small to larger scales. The exact balance
between these two effects depends on the details of outflows on small scales,
and quantitative estimates will require much more sophisticated modeling than
presented here.


title:
Dynamics of the NGC 4636 Globular Cluster System - An extremely dark
  matter dominated galaxy?

abstract:
  We present the first dynamical study of the globular cluster system of NGC
4636. This giant elliptical galaxy is claimed to be extremely dark matter
dominated, according to X-ray observations. Using the VLT with FORS2/MXU, we
obtained velocities for 174 globular clusters. The clusters have projected
galactocentric distances in the range 4 to 70 kpc, the overwhelming majority
lie within 30 kpc. We find some indication for a rotation of the red
(metal-rich) clusters about the minor axis. Out to a radius of 30 kpc, we find
a roughly constant projected velocity dispersion for the blue clusters of ~200
km/s. The red clusters exhibit a distinctly different behavior: at a radius of
about 13 kpc, the velocity dispersion drops by ~50 km/s to about 170 km/s which
then remains constant out to a radius of 30 kpc.
  Using only the blue clusters as dynamical tracers, we perform Jeans-analyses
for different assumptions of the orbital anisotropy. Depending on the
anisotropy and the adopted M/L-values, we find that the dark matter fraction
within one effective radius can vary between 20% and 50% with most a probable
range between 20% and 30%. A main source of uncertainty is the ambiguity of the
velocity dispersion in the outermost bin.
  Although the dark halo mass still cannot be strongly constrained, NGC 4636
does not seem to be extremely dark matter dominated. The derived circular
velocities are also consistent with Modified Newtonian Dynamics.


title: The Lyman-alpha forest and WMAP year three

abstract:
  A combined analysis of Cosmic Microwave Background (CMB) and Lyman-a forest
data allows to constrain the matter power spectrum from small scales of about 1
Mpc/h all the way to the horizon scale. The long lever arm and complementarity
provided by such an analysis has previously led to a significant tightening of
the constraints on the shape and the amplitude of the power spectrum of
primordial density fluctuations. We present here a combined analysis of the
WMAP three year results with Lyman-a forest data. The amplitude of the matter
power spectrum sigma_8 and the spectral index ns inferred from the joint
analysis with high resolution Lyman-a forest data and low resolution Lyman-a
forest data as analyzed by Viel & Haehnelt (2006) are consistent with the new
WMAP results to within 1 sigma. The joint analysis with the mainly low
resolution data as analysed by McDonald et al. (2005) suggests a value of
sigma_8 which is ~ 2 sigma higher than that inferred from the WMAP three year
data alone. The joint analysis of the three year WMAP and the Lyman-a forest
data also does not favour a running of the spectral index. The best fit values
for a combined analysis of the three year WMAP data, other CMB data, 2dF and
the Lyman-a forest data are (sigma_8, ns) = (0.78\pm 0.03,0.96 \pm 0.01).


title: On the status of superheavy dark matter

abstract:
  Superheavy particles are a natural candidate for the dark matter in the
universe and our galaxy, because they are produced generically during inflation
in cosmologically interesting amounts. The most attractive model for the origin
of superheavy dark matter (SHDM) is gravitational production at the end of
inflation. The observed cosmological density of dark matter determines the mass
of the SHDM particle as $m_X=$(a few)$\:\times 10^{13}$ GeV, promoting it to a
natural candidate for the source of the observed ultra-high energy cosmic rays
(UHECR). After a review of the theoretical aspects of SHDM, we up-date its
predictions for UHECR observations: no GZK cutoff, flat energy spectrum with
$dN/dE\approx 1/E^{1.9}$, photon dominance and galactic anisotropy. We analyze
the existing data and conclude that SDHM as explanation for the observed UHECRs
is at present disfavored but not yet excluded. We calculate the anisotropy
relevant for future Auger observations that should be the conclusive test for
this model. Finally, we emphasize that negative results of searches for SHDM in
UHECR do not disfavor SHDM as a dark matter candidate. Therefore, UHECRs
produced by SHDM decays and with the signatures as described should be searched
for in the future as subdominant effect.


title:
Acoustic oscillations in rapidly rotating polytropic stars I. Effects of
  the centrifugal distortion

abstract:
  A new non-perturbative method to compute accurate oscillation modes in
rapidly rotating stars is presented. In this paper, the effect of the
centrifugal force is fully taken into account while the Coriolis force is
neglected. This assumption is valid when the time scale of the oscillation is
much shorter than the inverse of the rotation rate and is expected to be
suitable for high radial order p-modes of $\delta$ Scuti stars. Axisymmetric
p-modes have been computed in uniformly rotating polytropic models of stars. In
the frequency and rotation range considered, we found that as rotation
increases (i) the asymptotic structure of the non-rotating frequency spectrum
is first destroyed then replaced by a new form of organization (ii) the mode
amplitude tends to concentrate near the equator (iii) differences with
perturbative methods become significant as soon as the rotation rate exceeds
about fifteen percent of the Keplerian limit. The implications for the
seismology of rapidly rotating stars are then discussed.


title:
On the AU Mic debris disk: density profiles, grain properties and dust
  dynamics

abstract:
  We present the first comprehensive analysis of the AU Mic debris disk
properties since the system was discovered by Kalas et al. (2004), and we
explore whether the dynamical model, successful to reproduce the Beta Pic
brightness profile could apply to AU Mic. We calculate the surface density
profile of the AU Mic disk by performing the inversion of the near-IR and
visible scattered light brightness profiles measured by Liu (2004a) and Krist
et al. (2005), respectively. We discuss the grain properties by analysing the
blue color of the disk in the visible (Krist et al. 2005) and by fitting the
disk spectral energy distribution. We show that irrespective of the mean
scattering asymmetry factor of the grains, most of the emission arises from an
asymmetric, collisionally-dominated region that peaks close to the surface
brightness break around 35 AU. The elementary scatterers at visible wavelengths
are found to be sub-micronic, but the inferred size distribution underestimates
the amount of large grains, resulting in too low sub-millimeter emissions
compared to the observations. From our inversion procedure, we find that the V-
to H-band scattering cross sections ratio increases outside 40 AU, in line with
the observed color gradient of the disk. We show that a standard, solar-like
stellar wind generates a pressure force onto the dust particles that behaves
much like a radiation pressure force. With an assumed Mdot ~ 300 Mdot_sun, the
wind pressure overcomes the radiation pressure and this effect is enhanced by
the stellar flares. This explains the similarity between the Beta Pic and AU
Mic brightness profiles. In both cases, the color gradient beyond 120 AU for
Beta Pic and 35 AU for AU Mic, is believed to be a direct consequence of the
dust dynamics.


title: The White Dwarf in AE Aqr Brakes Harder

abstract:
  Taking advantage of the very precise de Jager et al. optical white dwarf
orbit and spin ephemerides; ASCA, XMMN, and Chandra X-ray observations spread
over 10 yrs; and a cumulative 27 yr baseline, we have found that in recent
years the white dwarf in AE Aqr is spinning down at a rate that is slightly
faster than predicted by the de Jager et al. spin ephemeris. At the present
time, the observed period evolution is consistent with either a cubic term in
the spin ephemeris with Pdouble_dot = 3.46(56)E-19 per d, which is inconsistent
in sign and magnitude with magnetic-dipole radiation losses, or an additional
quadratic term with Pdot = 2.0(1.0)E-15 d/d, which is consistent with a modest
increase in the accretion torques spinning down the white dwarf. Regular
monitoring, in the optical, ultraviolet, and/or X-rays, is required to track
the evolution of the spin period of the white dwarf in AE Aqr.


title:
Low Mass Stars and Brown Dwarfs in NGC 2024: Constraints on the
  Substellar Mass Function

abstract:
  We present results from a near-infrared spectroscopic study of candidate
brown dwarfs and low mass stars in the young cluster NGC 2024. Using FLAMINGOS
on the KPNO 2.1m and 4m telescopes, we have obtained spectra of ~70 new members
of the cluster and classified them via the prominent J and H band water
absorption features. Derived spectral types range from ~M1 to later than M8
with typical classification errors of 0.5-1 subclasses. By combining these
spectral types with JHK photometry, we place these objects on the H-R diagram
and use pre-main sequence evolutionary models to infer masses and ages. The
mean age for this low mass population of NGC 2024 is 0.5 Myr and derived masses
range from ~0.7-0.02 solar masses with 23 objects falling below the
hydrogen-burning limit. The logarithmic mass function rises to a peak at ~0.2
solar masses before turning over and declining into the substellar regime.
There is a possible secondary peak at ~0.035 solar masses however the errors
are also consistent with a flat IMF in this region. The ratio of brown dwarfs
to stars is similar to that found in the Trapezium but roughly twice the ratio
found in IC 348, leading us to conclude that the substellar IMF in young
clusters may be dependent on the local star forming environment.


title:
Optical, Infrared, and Ultraviolet Observations of the X-Ray Flash GRB
  050416A

abstract:
  We present ultraviolet, optical, and infrared photometry of the afterglow of
the X-ray flash XRF 050416A taken between approximately 100 seconds and 36 days
after the burst. We find an intrinsic spectral slope between 1930 and 22,200
Angstrom of beta = -1.14 +/- 0.20 and a decay rate of alpha = -0.86 +/- 0.15.
There is no evidence for a change in the decay rate between approximately 0.7
and 4.7 days after the burst. Our data implies that there is no spectral break
between the optical and X-ray bands between 0.7 and 4.7 days after the burst,
and is consistent with the cooling break being redward of the K_s band (22,200
Angstrom) at 0.7 days. The combined ultraviolet/optical/infrared spectral
energy distribution shows no evidence for a significant amount of extinction in
the host galaxy along the line of sight to XRF 050416A. Our data suggest that
the extragalactic extinction along the line of sight to the burst is only
approximately A_V = 0.2 mag, which is significantly less than the extinction
expected from the hydrogen column density inferred from $X$-ray observations of
XRF 050416A assuming a dust-to-gas ratio similar to what is found for the Milky
Way. The observed extinction, however, is consistent with the dust-to-gas ratio
seen in the Small Magellanic Cloud. We suggest that XRF 050416A may have a
two-component jet similar to what has been proposed for GRB 030329. If this is
the case the lack of an observed jet break between 0.7 and 42 days is an
illusion due to emission from the wide jet dominating the afterglow after
approximately 1.5 days.


title:
SINFONI adaptive optics integral field spectroscopy of the Circinus
  Galaxy

abstract:
  Aims. To investigate the star formation activity and the gas and stellar
dynamics on scales of a few parsecs in the nucleus of the Circinus Galaxy.
Methods.Using the adaptive optics near infrared integral field spectrometer
SINFONI on the VLT, we have obtained observations of the Circinus galaxy on
scales of a few parsecs and at a spectral resolution of 70 km s^{-1} FWHM. The
physical properties of the nucleus are analyzed by means of line and velocity
maps extracted from the SINFONI datacube. Starburst models are constrained
using the Br-gamma flux, stellar continuum (as traced via the CO absorption
bandheads longward of 2.3um), and radio continuum. Results. The similarity of
the morphologies of the H_2 (1-0)S(1) 2.12um and Br-gamma 2.17um lines to the
stellar continuum and also their kinematics, suggest a common origin in star
formation. Within 8 pc of the AGN we find there has been a recent starburst in
the last 100 Myr, which currently accounts for 1.4% of the galaxy's bolometric
luminosity. The similarity of the spatial scales over which the stars and gas
exist indicates that this star formation is occuring within the torus; and
comparison of the gas column density through the torus to the maximum possible
optical depth to the stars implies the torus is a clumpy medium. The coronal
lines show asymmetric profiles with a spatially compact narrow component and a
spatially extended blue wing. These characteristics are consistent with some of
the emission arising in clouds gravitationally bound to the AGN, and some
outflowing in cloudlets which have been eroded away from the bound clouds.


title:
Chandra X-Ray Observations of Nineteen Millisecond Pulsars in the
  Globular Cluster 47 Tucanae

abstract:
  We present spectral and long-timescale variability analyses of
\textit{Chandra} ACIS-S observations of the 19 millisecond pulsars (MSPs) with
precisely known positions in the globular cluster 47 Tucanae. The X-ray
emission of the majority of these MSPs is well described by a thermal
(blackbody or neutron star hydrogen atmosphere) spectrum with a temperature
$T_{\rm eff}\sim(1-3)\times10^6$ K, emission radius $R_{\rm eff}\sim0.1-3$ km,
and luminosity $L_{X}\sim10^{30-31}$ ergs s$^{-1}$. For several MSPs, there is
indication that a second thermal component is required, similar to what is seen
in some nearby field MSPs. The radio-eclipsing binary MSPs 47 Tuc J, O, and W
show a significant non-thermal component, with photon index $\Gamma\sim 1-1.5$,
which may originate in an shock formed due to interaction between the
relativistic pulsar wind and matter from the stellar companion. We re-examine
the X-ray--spindown luminosity relation ($L_{X}-\dot{E}$) and find that due to
the large uncertainties in both parameters the result is consistent with both
the linear $L_{X}-\dot{E}$ relation and the flatter $L_X\propto\dot{E}^{0.5}$
predicted by polar cap heating models. In terms of X-ray properties, we find no
clear systematic differences between MSPs in globular clusters and in the field
of the Galaxy.


title: Pulsational Instabilities in Accreting White Dwarfs

abstract:
  (Abridged) The Cataclysmic Variable (CV) population harbors a diverse range
of donor stars and accreting white dwarfs (WDs). A range of WD masses is
expected, from low mass Helium core WDs, to massive WDs which have previously
accreted at rates high enough for Hydrogen to burn steadily. Furthermore, a
wide range of Helium enrichment is expected in the accreted material depending
on the degree to which the donor star is evolved. We investigate the impact of
this diversity on the range of effective temperatures ($T_{\rm eff}$) for which
g-modes are unstable. The critical $T_{\rm eff}$ below which modes are unstable
("blue edge") depends on both surface gravity, $g$, and He abundance, $Y$. The
Hydrogen/first Helium ionization instability strip is more sensitive to $g$
than $Y$. We find that (for solar composition envelopes), relative to a
fiducial WD mass $0.6 M_\odot$, the blue edge for a $0.4 M_\odot$ He core WD
shifts downward by $\approx 1000 {\rm K}$, while that for a massive $\approx
1.2 M_\odot$ WD shifts upward by $\approx 2000 {\rm K}$. The second Helium
ionization instability strip exhibits strong dependences on both $g$ and $Y$.
Surprisingly, increasing $Y$ by only 10% relative to solar creates an
instability strip near $15,000 {\rm K}$. Hence CV's below the period gap with
evolved donor stars of $Y\ga 0.4$ may have an "intermediate" instability strip
well outside of the isolated DA and DB variables. This "intermediate"
instability strip also occurs for low mass He WD with solar composition
envelopes. The lack of pulsations in CV's with $T_{\rm eff}$ in the pure
Hydrogen ZZ Ceti instability strip is also easily explained.


title:
Jet Breaks in Short Gamma-Ray Bursts. II: The Collimated Afterglow of
  GRB 051221A

abstract:
  We report the best evidence to date of a jet break in a short Gamma-Ray Burst
(GRB) afterglow, using Chandra and Swift XRT observations of the X-ray
afterglow of GRB 051221A. The combined X-ray light curve, which has three
breaks, is similar to those commonly observed in Swift observations of long
GRBs. A flat segment of the light curve at ~0.1 days after the burst represents
the first clear case of strong energy injection in the external shock of a
short GRB afterglow. The last break occurs at ~4 days post-burst and breaks to
a power-law decay index of ~2. We interpret this as a jet break, with important
implications for models of short GRBs, since it requires collimation of the
afterglow into a jet with an initial opening angle ~4-8 degrees and implies a
total jet kinetic energy of E_jet ~(1-5) x 10^{49} erg. Combined with the lack
of a jet break in GRB 050724, this suggests a wide range in jet collimation in
short GRBs, with at least some having collimation similar to that found in long
GRBs, though with significantly lower jet energies.


title: Star Formation in Satellite Galaxies

abstract:
  We present narrow-band observations of the H$\alpha$ emission in a sample of
31 satellite orbiting isolated giant spiral galaxies. The sample studied spans
the range $-19<M_B <-15$ mag. The H$\alpha$ emission was detected in all the
spiral and irregular objects with fluxes in the range $1.15-49.80\times
10^{-14}$ erg cm$^{-2}$ s$^{-1}$. The average and maximum values for the
current star formation rates are 0.68 and 3.66 M$_\sun$ yr$^{-1}$ respectively.
Maps of the spatial distribution of ionized gas are presented. The star-forming
regions show a rich structure in which frequently discrete complexes are
imposed over more diffuse structures. In general, the current star formation
rates are smaller that the mean values in the past obtained from the current
stellar content; this probably indicates a declining rhythm with time in the
generation of new stars. However, the reserve of gas is enough to continue
fueling the current levels of star formation activity for at least another
Hubble time. Four of the objects (NGC 2718b, NGC 4541e, NGC 5965a$_1$ and NGC
5965a$_2$) with higher current star formation rates show clear signs of
interaction with close companions of comparable brightness at projected
distances of 25, 20 and 2 kpc respectively. The only two galaxies in our sample
that do not show star formation activity are members of these interacting
systems, and it is unclear if this is a consequence of intrinsic properties
(both are Hubble early types) or if it is related with possible disruption of
the external parts due to the interaction. In the case of the pair NGC 2718a-b
there are indications of gas transport between both galaxies.


title: Characterizing Charge Diffusion in CCDs with X-rays

abstract:
  We demonstrate the effectiveness of two techniques for using x-rays to
evaluate the amount of charge diffusion in charge coupled devices (CCDs). We
quantify the degree of charge diffusion with two parameters: sigma_d, the
standard deviation for a Gaussian diffusion model, and Q, a ratio of the point
spread function (PSF) peak to its wings. sigma_d and Q are determined by
fitting a model to a pixel energy histogram, and by summing the PSF of all
x-ray events, respectively. Using seven test devices, we investigate the
precision of these two techniques and demonstrate that they produce compatible
results. The histogram fitting method is sensitive to the structure of the
electric field within these devices, in addition to the inherent charge
diffusion properties. The Q ratio is a very simple parameter to measure and
provides an easily accessible method for quickly evaluating a CCD's diffusion
length.


title: Does the Milky Way Produce a Nuclear Galactic Wind?

abstract:
  We detect high-velocity absorbing gas using Hubble Space Telescope and Far
Ultraviolet Spectroscopic Explorer medium resolution spectroscopy along two
high-latitude AGN sight lines (Mrk 1383 and PKS 2005-489) above and below the
Galactic Center (GC). These absorptions are most straightforwardly interpreted
as a wind emanating from the GC which does not escape from the Galaxy's
gravitational potential. Spectra of four comparison B stars are used to
identify and remove foreground velocity components from the absorption-line
profiles of O VI, N V, C II, C III, C IV, Si II, Si III, and Si IV. Two
high-velocity (HV) absorption components are detected along each AGN sight
line, three redshifted and one blueshifted. Assuming that the four HV features
trace a large-scale Galactic wind emanating from the GC, the blueshifted
absorber is falling toward the GC at a velocity of 250 +/- 20 km/s, which can
be explained by "Galactic fountain" material that originated in a bound
Galactic wind. The other three absorbers represent outflowing material; the
largest derived outflow velocity is +250 +/- 20 km/s, which is only 45% of the
velocity necessary for the absorber to escape from its current position in the
Galactic gravitational potential. All four HV absorbers are found to reach the
same maximum height above the Galactic plane (|z_max| = 12 +/- 1 kpc), implying
that they were all ejected from the GC with the same initial velocity. The
derived metallicity limits of >10-20% Solar are lower than expected for
material recently ejected from the GC unless these absorbers also contain
significant amounts of hotter gas in unseen ionization stages.


title:
Tomography of the Reionization Epoch with Multifrequency CMB
  Observations

abstract:
  We study the constraints that future multifrequency Cosmic Microwave
Background (CMB) experiments will be able to set on the metal enrichment
history of the Inter Galactic Medium at the epoch of reionisation. We forecast
the signal to noise ratio for the detection of the signal introduced in the CMB
by resonant scattering off metals at the end of the Dark Ages. We take into
account systematics associated to inter-channel calibration, PSF reconstruction
errors and innacurate foreground removal. We develop an algorithm to optimally
extract the signal generated by metals during reionisation and to remove
accurately the contamination due to the thermal Sunyaev-Zel'dovich effect.
Although demanding levels of foreground characterisation and control of
systematics are required, they are very distinct from those encountered in
HI-21cm studies and CMB polarization, and this fact encourages the study of
resonant scattering off metals as an alternative way of conducting tomography
of the reionisation epoch. An ACT-like experiment with optimistic assumtions on
systematic effects, and looking at clean regions of the sky, can detect changes
of 3%-12% (95% c.l.) of the OIII abundance (with respect its solar value) in
the redshift range $z\in$ [12,22], for reionization redshift $z_{\rm re}>10$.
However, for $z_{\rm re} <10$, it can only set upper limits on NII abundance
increments of $\sim$ 60% its solar value in the redshift range $z\in$ [5.5,9],
(95% c.l.). These constraints assume that inter-channel calibration is accurate
down to one part in $10^{4}$, which constitutes the most critical technical
requirement of this method, but still achievable with current technology.


title: Delayed X- and Gamma-Ray Line Emission from Solar Flare Radioactivity

abstract:
  We have studied the radioactive line emission expected from solar active
regions after large flares, following the production of long-lived
radioisotopes by nuclear interactions of flare-accelerated ions. This delayed
X- and gamma-ray line emission can provide unique information on the
accelerated particle composition and energy spectrum, as well as on mixing
processes in the solar atmosphere. Total cross sections for the formation of
the main radioisotopes by proton, 3-He and alpha-particle reactions are
evaluated from available data combined with nuclear reaction theory.
Thick-target radioisotope yields are provided in tabular form, which can be
used to predict fluxes of all of the major delayed lines at any time after a
gamma-ray flare. The brightest delayed line for days after the flare is found
to be the 511 keV positron-electron annihilation line resulting from the decay
of several beta+ radioisotopes. After ~2 days however, the flux of the 511 keV
line can become lower than that of the 846.8 keV line from the decay of 56-Co.
Our study has revealed other delayed gamma-ray lines that appear to be
promising for detection, e.g. at 1434 keV from the radioactivity of both the
isomer and the ground state of 52-Mn, 1332 and 1792 keV from 60-Cu, and 931.1
keV from 55-Co. The strongest delayed X-ray line is found to be the Co Kalpha
at 6.92 keV, which is produced from both the decay of the isomer of 58-Co by
the conversion of a K-shell electron and the decay of 57-Ni by orbital electron
capture. Prospects for observation of these lines with RHESSI or future space
instruments are discussed.


title: The Swift satellite and redshifts of long gamma-ray bursts

abstract:
  Until 6 October 2005 sixteen redshifts have been measured of long gamma-ray
bursts discovered by the Swift satellite. Further 45 redshifts have been
measured of the long gamma-ray bursts discovered by other satellites. Here we
perform five statistical tests comparing the redshift distributions of these
two samples assuming - as the null hypothesis - identical distribution for the
two samples. Three tests (Student's $t$-test, Mann-Whitney test,
Kolmogorov-Smirnov test) reject the null hypothesis on the significance levels
between 97.19 and 98.55%. Two different comparisons of the medians show extreme
$(99.78-99.99994)$% significance levels of rejection. This means that the
redshifts of the Swift sample and the redshifts of the non-Swift sample are
distributed differently - in the Swift sample the redshifts are on average
larger. This statistical result suggests that the long GRBs should on average
be at the higher redshifts of the Swift sample.


title: Top ten accelerating cosmological models

abstract:
  Recent astronomical observations indicate that the Universe is presently
almost flat and undergoing a period of accelerated expansion. Basing on
Einstein's general relativity all these observations can be explained by the
hypothesis of a dark energy component in addition to cold dark matter (CDM).
Because the nature of this dark energy is unknown, it was proposed some
alternative scenario to explain the current accelerating Universe. The key
point of this scenario is to modify the standard FRW equation instead of
mysterious dark energy component. The standard approach to constrain model
parameters, based on the likelihood method, gives a best-fit model and
confidence ranges for those parameters. We always arbitrary choose the set of
parameters which define a model which we compare with observational data.
Because in the generic case, the introducing of new parameters improves a fit
to the data set, there appears the problem of elimination of model parameters
which can play an insufficient role. The Bayesian information criteria of model
selection (the AIC and BIC) are dedicated to promotion a set of parameters
which should be incorporated to the model. We divide class of all accelerating
cosmological models into two groups according to the two types of explanation
acceleration of the Universe. Then the Bayesian framework of model selection is
used to determine the set of parameters which gives preferred fit to the SNIa
data. We find a few of flat cosmological models which can be recommend by both
the Bayes factor and Akaike information criterion.


title:
Outflows from the high-mass protostars NGC 7538 IRS1/2 observed with
  bispectrum speckle interferometry -- Signatures of flow precession

abstract:
  NGC 7538 IRS1 is a high-mass (approx. 30 M_sun) protostar with a CO outflow,
an associated UCHII region, and a linear methanol maser structure, which might
trace a Keplerian-rotating circumstellar disk. The directions of the various
associated axes are misaligned with each other. We investigate the
near-infrared morphology of the source to clarify the relations among the
various axes. K'-band bispectrum speckle interferometry was performed at two
6-meter-class telescopes -- the BTA 6m telescope and the 6.5m MMT.
Complementary IRAC images from the Spitzer Space Telescope Archive were used to
relate the structures detected with the outflow at larger scales. High-dynamic
range images show fan-shaped outflow structure in which we detect 18 stars and
several blobs of diffuse emission. We interpret the misalignment of various
outflow axes in the context of a disk precession model, including numerical
hydrodynamic simulations of the molecular emission. The precession period is
approx. 280 years and its half-opening angle is 40 degrees. A possible
triggering mechanism is non-coplanar tidal interaction of an (undiscovered)
close companion with the circumbinary protostellar disk. Our observations
resolve the nearby massive protostar NGC 7538 IRS2 as a close binary with
separation of 195 mas. We find indications for shock interaction between the
outflow activities in IRS1 and IRS2. Indications of outflow precession have
been discovered to date in a number of massive protostars, all with large
precession angles 20--45 degrees. This might explain the difference between the
outflow widths in low- and high-mass stars and add support to a common
collimation mechanism.


title:
A close look to quasar-triggered winds: is the black hole-bulge relation
  self-regulated?

abstract:
  We discuss the role of feedback from AGNs on the formation of spheroidal
galaxies. The energy released by an accreting Black Hole (BH) may be injected
into the ISM through blast waves arising directly from the central engine,
radiation pressure or radiative heating. A scenario is described in which
radiative heating perturbs the methabolism of a star-forming spheroid, leading
to a critical stage where SNe form a cold expanding shell, pushed out of the
galaxy by radiation pressure from the AGN. This mechanism can regulate the
BH--bulge relation to the observed value. However, this relation may be simply
imprinted by the mechanism responsible for the nearly complete loss of angular
momentum of the gas that accretes onto the BH. Using a novel model of galaxy
formation that includes AGNs, we show that models without self-regulation have
problems in reproducing the correct slope of the AGN luminosity function, while
models with winds give a much better fit; however, all these models are almost
indistingishable as far as their predicted BH--bulge relation is concerned.
Finally, we show that the downsizing of the faint AGNs is most likely due to
kinetic feedback in star-forming bulges.


abstract:
  PG 0014+067 is one of the most promising pulsating subdwarf B stars for
seismic analysis, as it has a rich pulsation spectrum. The richness of its
pulsations, however, poses a fundamental challenge to understanding the
pulsations of these stars, as the mode density is too complex to be explained
only with radial and nonradial low degree (l < 3) p-modes without rotational
splittings. One proposed solution, for the case of PG 0014+067 in particular,
assigns some modes with high degree (l=3). On the other hand, theoretical
models of sdB stars suggest that they may retain rapidly rotating cores, and so
the high mode density may result from the presence of a few rotationally-split
triplet (l=1), quintuplet (l=2) modes, along with radial (l=0) p-modes. To
examine alternative theoretical models for these stars, we need better
frequency resolution and denser longitude coverage. Therefore, we observed this
star with the Whole Earth Telescope for two weeks in October 2004. In this
paper we report the results of Whole Earth Telescope observations of the
pulsating subdwarf B star PG 0014+067. We find that the frequencies seen in PG
0014+067 do not appear to fit any theoretical model currently available;
however, we find a simple empirical relation that is able to match all of the
well-determined frequencies in this star.


title: Optimal Image Reconstruction in Radio Interferometry

abstract:
  We introduce a method for analyzing radio interferometry data which produces
maps which are optimal in the Bayesian sense of maximum posterior probability
density, given certain prior assumptions. It is similar to maximum entropy
techniques, but with an exact accounting of the multiplicity instead of the
usual approximation involving Stirling's formula. It also incorporates an Occam
factor, automatically limiting the effective amount of detail in the map to
that justified by the data. We use Gibbs sampling to determine, to any desired
degree of accuracy, the multi-dimensional posterior density distribution. From
this we can construct a mean posterior map and other measures of the posterior
density, including confidence limits on any well-defined function of the
posterior map.


title:
Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky
  Survey

abstract:
  We report on the detection in Sloan Digital Sky Survey data of a 63
degree-long tidal stream of stars, extending from Ursa Major to Cancer. The
stream has no obvious association with the orbit of any known cluster or
galaxy. The contrast of the detected stream is greatest when using a star count
filter that is matched to the color-magnitude distribution of stars in M 13,
which suggests that the stars making up the stream are old and metal poor. The
visible portion of the stream is very narrow and about 8.5 kpc above the
Galactic disk, suggesting that the progenitor is or was a globular cluster.
While the surface density of the stream varies considerably along its length,
its path on the sky is very smooth and uniform, showing no evidence of
perturbations by large mass concentrations in the nearby halo. While definitive
constraints cannot be established without velocity information, the stream's
projected path and estimates of its distance suggest that we are observing the
stream near the perigalacticon of its orbit.


title:
The secrets of the nearest starburst cluster: II. The present-day mass
  function in NGC 3603

abstract:
  Based on deep VLT/ISAAC JHK photometry, we have derived the present-day mass
function of the central starburst cluster NGC 3603 YC (Young Cluster) in the
giant HII region NGC 3603. The effects of field contamination, individual
reddening, and a possible binary contribution are investigated. The MF slopes
resulting from the different methods are compared, and lead to a surprisingly
consistent cluster MF with a slope of Gamma = -0.9 +/- 0.15. Analyzing
different radial annuli around the cluster core, no significant change in the
slope of the MF is observed. However, mass segregation in the cluster is
evidenced by the increasing depletion of the high-mass tail of the stellar mass
distribution with increasing radius. We discuss the indications of mass
segregation with respect to the changes observed in the binned and cumulative
stellar mass functions, and argue that the cumulative function as well as the
fraction of high- to low-mass stars provide better indicators for mass
segregation than the MF slope alone. (abridged)