title:
Probing Dark Energy via Weak Gravitational Lensing with the SuperNova
  Acceleration Probe (SNAP)

abstract:
  SNAP is a candidate for the Joint Dark Energy Mission (JDEM) that seeks to
place constraints on the dark energy using two distinct methods. The first,
Type Ia SN, is discussed in a companion white paper. The second method is weak
gravitational lensing, which relies on the coherent distortions in the shapes
of background galaxies by foreground mass structures. The excellent spatial
resolution and photometric accuracy afforded by a 2-meter space-based
observatory are crucial for achieving the high surface density of resolved
galaxies, the tight control of systematic errors in the telescope's Point
Spread Function (PSF), and the exquisite redshift accuracy and depth required
by this project. These are achieved by the elimination of atmospheric
distortion and much of the thermal and gravity loads on the telescope. The SN
and WL methods for probing dark energy are highly complementary and the error
contours from the two methods are largely orthogonal.


title:
Observational Constraints Upon Cool Disk Material in Quiescent Black
  Hole Binaries

abstract:
  We consider current observational constraints on the presence of cool,
optically thick disk material in quiescent black hole binaries, specifically
focusing on a case study of the prototypical system A0620-00. Such material
might be expected to be present theoretically, but is usually claimed to make a
negligible contribution at optical and infrared wavelengths. The primary
argument is based on measurements of the veiling of stellar photospheric
absorption lines, in which it is assumed that the disk spectrum is featureless.
We use simulated spectra to explore the sensitivity of veiling measurements to
uncertainties in companion temperature, gravity, and metallicity. We find that
the derived veiling is extremely sensitive to a mismatch between the
temperature and metallicity of the companion and template, but that the effect
of a plausible gravity mismatch is much smaller. In general the resulting
uncertainty in the amount of veiling is likely to be much larger than the
usually quoted statistical uncertainty. We also simulate spectra in which the
disk has an emergent spectrum similar to the star and find that in this case,
optical veiling constraints are moderately robust. This is because the
rotational broadening of the disk is so large that the two line profiles
effectively decouple and the measurement of the depth of stellar lines is
largely unbiased by the disk component. We note, however, that this is only
true at intermediate resolutions or higher, and that significant bias might
still affect low resolution IR observations. [Abridged]


title: The Magnetic Structure of Coronal Loops Observed by TRACE

abstract:
  Previous studies have found that coronal loops have a nearly uniform
thickness, which seems to disagree with the characteristic expansion of active
region magnetic fields. This is one of the most intriguing enigmas in solar
physics. We here report on the first comprehensive one-to-one comparison of
observed loops with corresponding magnetic flux tubes obtained from cotemporal
magnetic field extrapolation models. We use EUV images from TRACE, magnetograms
from the MDI instrument on SOHO, and linear force-free field extrapolations.
For each loop, we find the particular value of the force-free parameter (alpha)
that best matches the observed loop axis and then construct flux tubes using
different assumed cross sections at one footpoint (circle and ellipses with
different orientations). We find that the flux tubes expand with height by
typically twice as much as the corresponding loops. We also find that many flux
tubes are much wider at one footpoint than the other, whereas the corresponding
loops are far more symmetric. It is clear that the actual coronal magnetic
field is more complex than the models we have considered. We suggest that the
observed symmetry of loops is related to the tangling of elemental magnetic
flux strands produced by photospheric convection.


title: Hot and Diffuse Clouds near the Galactic Center Probed by Metastable H3+

abstract:
  Using an absorption line from the metastable (J, K) = (3, 3) level of H3+
together with other lines of H3+ and CO observed along several sightlines, we
have discovered a vast amount of high temperature (T ~ 250 K) and low density
(n ~ 100 cm-3) gas with a large velocity dispersion in the Central Molecular
Zone (CMZ) of the Galaxy, i.e., within 200 pc of the center. Approximately
three fourths of the H3+ along the line of sight to the brightest source we
observed, the Quintuplet object GCS 3-2, is inferred to be in the CMZ, with the
remaining H3+ located in intervening spiral arms. About half of H3+ in the CMZ
has velocities near ~ - 100 km s-1 indicating that it is associated with the
180 pc radius Expanding Molecular Ring which approximately forms outer boundary
of the CMZ. The other half, with velocities of ~ - 50 km s-1 and ~ 0 km s-1, is
probably closer to the center. CO is not very abundant in those clouds. Hot and
diffuse gas in which the (3, 3) level is populated was not detected toward
several dense clouds and diffuse clouds in the Galactic disk where large column
densities of colder H3+ have been reported previously. Thus the newly
discovered environment appears to be unique to the CMZ. The large observed H3+
column densities in the CMZ suggests an ionization rate much higher than in the
diffuse interstellar medium in the Galactic disk. Our finding that the H3+ in
the CMZ is almost entirely in diffuse clouds indicates that the reported volume
filling factor (f ≥ 0.1) for n ≥ 104 cm-3 clouds in the CMZ is an
overestimate by at least an order of magnitude.


title:
Horizontal Branch Stars: The Interplay between Observations and Theory,
  and Insights into the Formation of the Galaxy

abstract:
  We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]


title:
Search for Cross-Correlations of Ultra--High-Energy Cosmic Rays with BL
  Lacertae Objects

abstract:
  We present the results of searches for correlation between ultra--high-energy
cosmic rays observed in stereo mode by the High Resolution Fly's Eye (HiRes)
experiment and objects of the BL Lac subclass of active galaxies. In
particular, we discuss an excess of events correlating with confirmed BL Lacs
in the Veron 10th Catalog. As described in detail in Abbasi et al. (2005), the
significance level of these correlations cannot be reliably estimated due to
the a posteriori nature of the search, and the results must be tested
independently before any claim can be made. We identify the precise hypotheses
that will be tested with independent data.


title:
An improved formula for the relativistic corrections to the kinematical
  Sunyaev-Zeldovich effect for clusters of galaxies

abstract:
  We improve the calculation of Nozawa, Itoh, and Kohyama (1998) to provide a
formula for relativistic corrections to the thermal and kinematical
Sunyaev-Zeldovich effects that is accurate to fourth order in theta_e =
kT_e/m_ec^2, T_e and m_e being the electron temperature and electron mass,
respectively. We also carry out a direct numerical integration of the Boltzmann
collision term and confirm the excellent accuracy of the analytic formula. This
formula will be useful for the analysis of the observational data of the
forthcoming experiments of the kinematical Sunyaev-Zeldovich effect for
clusters of galaxies.


title:
Cross-Correlation Lensing: Determining Galaxy and Cluster Mass Profiles
  from Statistical Weak Lensing Measurements

abstract:
  We present a new non-parametric method for determining mean 3D density and
mass profiles from weak lensing measurements around stacked samples of galaxies
or clusters, that is, from measurement of the galaxy-shear or cluster-shear
correlation functions. Since the correlation function is statistically
isotropic, this method evades problems, such as projection of large-scale
structure along the line of sight or halo asphericity, that complicate attempts
to infer masses from weak lensing measurements of individual objects. We
demonstrate the utility of this method in measuring halo profiles, galaxy-mass
and cluster-mass cross-correlation functions, and cluster virial masses. We
test this method on an N-body simulation and show that it correctly and
accurately recovers the 3D density and mass profiles of halos. We find no
evidence of problems due to a mass sheet degeneracy in the simulation.
Cross-correlation lensing provides a powerful method for calibrating the
mass-observable relation for use in measurement of the cluster mass function in
large surveys. It can also be used on large scales to measure and remove the
halo bias and thereby provide a direct measurement of Omega_m * sigma_8.


title:
Recovery of the orbital parameters and pulse evolution of V0332+53
  during a huge outburst

abstract:
  The high mass X-ray binary (HMXB) V0332+53 became active at the end of 2004
and the outburst was observed at hard X-rays by RXTE and INTEGRAL. Based on
these hard X-ray observations, the orbital parameters are measured through
fitting the Doppler-shifted spin periods. The derived orbital period and
eccentricity are consistent with those of Stella et al. (1985) obtained from
EXOSAT observations, whereas the projected semimajor axis and the periastron
longitude are found to have changed from 48$\pm$4 to 86$^{+6}_{-10}$ lt-s and
from 313$^{\circ}$$\pm$10 to 283$^{\circ}$$\pm$14, respectively. This would
indicate an angular speed of $\geq$ 1.5$^{\circ}$$\pm$0.8 yr$^{-1}$ for
rotation of the orbit over the past 21 years. The periastron passage time of
MJD 53367$\pm$1 is just around the time when the intensity reached maximum and
an orbital period earlier is the time when the outburst started. This
correlation resembles the behavior of a Type I outburst. During outburst the
source spun up with a rate of 8.01$^{+1.00}_{-1.14}$$\times10^{-6}$ s
day$^{-1}$. The evolution of pulse profile is highly intensity dependent. The
separation of double pulses remained almost constant ($\sim$ 0.47) when the
source was bright, and dropped to 0.37 within $\leq$ 3 days as the source
became weaker. The pulse evolution of V0332+53 may correlate to the change in
dominance of the emission between fan-beam and pencil-beam mechanisms.


title: A variability study of the Seyfert 2 galaxy NGC 6300 with XMM-Newton

abstract:
  We present the results of timing analysis of the XMM-Newton observation of
the Seyfert 2 galaxy NGC 6300. The hard X-ray spectrum above 2 keV consists of
a Compton-thin-absorbed power law, as is often seen in Seyfert 2 galaxies. We
clearly detected rapid time variability on a time scale of about 1000 s from
the light curve above 2 keV. The excess variance of the time variability
(sigma2_RMS) is calculated to be ~0.12, and the periodogram of the light curve
is well represented by a power law function with a slope of 1.75. In contrast
with previous results from Seyfert 2 nuclei, these variability characteristics
are consistent with those of Seyfert 1 galaxies. This consistency suggests that
NGC 6300 has a similar black hole mass and accretion properties as Seyfert 1
galaxies. Using the relation between time variability and central black hole
mass by Hayashida et al. (1998), the black hole mass of NGC 6300 is estimated
to be ~2.8x10^5 Mo. Taking uncertainty of this method into account, the black
hole mass is less than 10^7 Mo. Taking the bolometric luminosity of 3.3x10^43
erg/s into consideration, this yields an accretion rate of > 0.03 of the
Eddington value, and comparable with estimates from Seyfert 1 galaxies using
this method. The time variability analysis suggests that NGC 6300 actually has
a Seyfert 1 nucleus obscured by a thick matter, and more generally provides a
new pillar of support for the unified model of Seyfert galaxies based on
obscuration.


title:
Identification of X-ray Point Sources and Study on the Nature of 62
  X-ray Globular Cluster Candidates in M31

abstract:
  This paper includes two parts. The first is to present the spectral energy
distributions (SEDs) of 49 globular cluster (GC) X-ray sources in the BATC 13
intermediate-band filters from 3800 to 10000 A, and identify 8 unidentified
X-ray sources in M31. Using the X-ray data of Einstein observation from 1979 to
1980, ROSAT HRI observation in 1990, Chandra HRC and ACIS-I observations from
1999 to 2001, and the BATC optical survey from 1995 to 1999, we find 49 GC
X-ray sources and 8 new unidentified X-ray sources in the BATC M31 field. By
analyzing SEDs and FWHMs, 4 of the 8 X-ray sources may be GC candidates. The
second is to present some statistical relationships about 62 GC X-ray sources,
of which 58 are already known, and 4 are identified in this paper. The
distribution of M31 GC X-ray sources' V mags is bimodal, with peaks at m_v =
15.65 and m_v = 17.89, which is different from the distribution of GC
candidates. The distribution of B-V color shows that,the GC X-ray sources seem
to be associated preferentially with the redder GCs, in agreement with the
previous results. Kolmogorov-Smirnov test shows that the maximum value of the
absolute difference of B-V distributions of GC X-ray sources and GCs is
D_{max}=0.181, and the probability P=0.068 which means we can reject the
hypothesis that the two distributions are the same at the 90.0% confidence
level. In the end, we study the correlation between X-ray luminosity (0.3-10
keV) and the optical luminosity (in V band) of the GC X-ray sources in M31, and
find that there exits a weak relationship with the linear correlation
coefficient r = 0.36 at the confidence level of 98.0%.


title:
The light curve of the semiregular variable L2 Puppis: II. Evidence for
  solar-like excitation of the oscillations

abstract:
  We analyse visual observations of the pulsations of the red giant variable L2
Pup. The data cover 77 years between 1927 and 2005, thus providing an extensive
empirical base for characterizing properties of the oscillations. The power
spectrum of the light curve shows a single mode resolved into multiple peaks
under a narrow envelope. We argue that this results from stochastic excitation,
as seen in solar oscillations. The random fluctuations in phase also support
this idea. A comparison with X Cam, a true Mira star with the same pulsation
period, and W Cyg, a true semiregular star, illustrates the basic differences
in phase behaviours. The Mira shows very stable phase, consistent with
excitation by the kappa-mechanism, whereas W Cyg shows large phase fluctuations
that imply stochastic excitation. We find L2 Pup to be intermediate, implying
that both mechanisms play a role in its pulsation. Finally, we also checked the
presence of low-dimensional chaos and could safely exclude it.


title: Smoothed Particle Hydrodynamics

abstract:
  Smoothed Particle Hydrodynamics (SPH) is a unique numerical method widely
used for astrophysical problems since it involves no spatial grid. Rather,
fluid quantities are carried by a set of Lagrangian `particles' which move with
the flow, meaning that complicated dynamics and asymmetric phenomena are
treated with ease. Since adaptivity is a built-in feature of the method there
is no need to resort to complicated additional mesh refinement procedures. In
this chapter we have undertaken a thorough review of the SPH method in order to
develop a sufficiently accurate method which can be applied to MHD problems
(Chapters 4-5). The review contains several results which have not been
published elsewhere.


title:
Measuring the geometry of the Universe in the presence of isocurvature
  modes

abstract:
  The Cosmic Microwave Background (CMB) anisotropy constrains the geometry of
the Universe because the positions of the acoustic peaks of the angular power
spectrum depend strongly on the curvature of underlying three-dimensional
space. In this Letter we exploit current observations to determine the spatial
geometry of the Universe in the presence of isocurvature modes. Previous
analyses have always assumed that the cosmological perturbations were initially
adiabatic. A priori one might expect that allowing additional isocurvature
modes would substantially degrade the constraints on the curvature of the
Universe. We find, however, that if one considers additional data sets, the
geometry remains well constrained. When the most general isocurvature
perturbation is allowed, the CMB alone can only poorly constrain the geometry
to Omega_0=1.6+-0.3. Including large-scale structure (LSS) data one obtains
Omega_0=1.07+-0.03, and Omega_0=1.06+-0.02 when supplemented by the Hubble
Space Telescope (HST) Key Project determination of H_0 and SNIa data.


title: Astrophysical Unipolar Inductors Powered by Gravitational Wave Emission

abstract:
  We consider the Unipolar Inductor Model (Goldreich & Lynden-Bell 1969)
applied to Double Degenerate Binaries (DDBs) with ultrashort periods (Wu et al.
2002). In this model a magnetized primary white dwarf has a slight asynchronism
between its spin and orbital motion, so that the (non-magnetic) secondary
experiences a motional electric field when moving through the primary field
lines. This induces a current flow between the two stars and provides an
electric spin-orbit coupling mechanism for the primary. We study the combined
effect of Gravitational Wave emission and electric spin-orbit coupling on the
evolution of the primary degree of asynchronism and the associated rate of
electric current dissipation in such systems, assuming that the primary's spin
is not affected by any other mechanisms. In particular, we show that in
ultrashort period binaries the emission of GW pumps energy in the electric
circuit as to keep it steadily active. This happens despite the fact that
spin-orbit coupling can rapidly synchronize the primary, because GW represent a
slow desynchronizing mechanism steadily substracting orbital angular momentum
to the system. A slightly asynchronous steady-state is thus achieved,
determined by the balance between these two competing effects. This can be
shown to correspond to a condition where the total available electric energy is
conserved, because of GW emission, while dissipation, synchronization and
orbital shrinking continue.


title: Site testing in summer at Dome C, Antarctica

abstract:
  We present summer site testing results based on DIMM data obtained at Dome C,
Antarctica. These data have been collected on the bright star Canopus during
two 3-months summer campaigns in 2003-2004 and 2004-2005. We performed
continuous monitoring of the seeing a nd the isoplanatic angle in the visible.
We found a median seeing of 0.54 \arcsec and a median isoplanatic angle of 6.8
\arcsec. The seeing appears to have a deep minimum around 0.4 \arcsec almost
every day in late afternoon.


title: Modelling NIR molecular lines for Miras

abstract:
  The atmospheric structure of Mira variables is considerably influenced by
pulsation. Molecular absorption lines in the near-infrared (NIR), especially
second overtone CO lines, show therefore a characteristic behaviour in
time-series of high-resolution spectra. We computed synthetic CO line profiles
based on a new dynamic model atmosphere and derived radial velocities (RVs)
from the Doppler shifted lines. For the first time, we could quantitatively
reproduce observations of the very typical, discontinuous RV curves.


title: Reducing the Probability of Capture into Resonance

abstract:
  A migrating planet can capture planetesimals into mean motion resonances.
However, resonant trapping can be prevented when the drift or migration rate is
sufficiently high. Using a simple Hamiltonian system for first and second order
resonances, we explore how the capture probability depends on the order of the
resonance, drift rate and initial particle eccentricity. We present scaling
factors as a function of the planet mass and resonance strength to estimate the
planetary migration rate above which the capture probability drops to less than
1/2. Applying our framework to multiple extra solar planetary systems that have
two planets locked in resonance, we estimate lower limits for the outer
planet's migration rate allowing resonance capture of the inner planet. Mean
motion resonances are comprised of multiple resonant subterms. We find that the
corotation subterm can reduce the probability of capture when the planet
eccentricity is above a critical value. We present factors that can be used to
estimate this critical planet eccentricity. Applying our framework to the
migration of Neptune, we find that Neptune's eccentricity is near the critical
value that would make its 2:1 resonance fail to capture twotinos. The capture
probability is affected by the separation between resonant subterms and so is
also a function of the precession rates of the longitudes of periapse of both
planet and particle near resonance.


title:
Cosmic Ray Acceleration at the Forward Shock in Tycho's Supernova
  Remnant: Evidence from Chandra X-ray Observations

abstract:
  We present evidence for cosmic ray acceleration at the forward shock in
Tycho's supernova remnant (SNR) from three X-ray observables: (1) the proximity
of the contact discontinuity to the forward shock, or blast wave, (2) the
morphology of the emission from the rim of Tycho, and (3) the spectral nature
of the rim emission. We determine the locations of the blast wave (BW), contact
discontinuity (CD), and reverse shock (RS) around the rim of Tycho's supernova
remnant using a principal component analysis and other methods applied to new
Chandra data. The azimuthal-angle-averaged radius of the BW is 251". For the CD
and RS we find average radii of 241" and 183", respectively. Taking account of
projection effects, we find ratios of 1:0.93:0.70 (BW:CD:RS). We show these
values to be inconsistent with adiabatic hydrodynamical models of SNR
evolution. The CD:BW ratio can be explained if cosmic ray acceleration of ions
is occurring at the forward shock. The RS:BW ratio, as well as the strong Fe Ka
emission from the Tycho ejecta, imply that the RS is not accelerating cosmic
rays. We also extract radial profiles from ~34% of the rim of Tycho and compare
them to models of surface brightness profiles behind the BW for a purely
thermal plasma with an adiabatic shock. The observed morphology of the rim is
much more strongly peaked than predicted by the model, indicating that such
thermal emission is implausible here. Spectral analysis also implies that the
rim emission is non-thermal in nature, lending further support to the idea that
Tycho's forward shock is accelerating cosmic rays.


title:
TeV Gamma-Ray Spectra Unfolded for IR Absorption for a Sample of Low and
  High Red-Shifted AGN

abstract:
  The H.E.S.S. collaboration recently performed the accurate measurements of
the gamma-ray spectra above 200 GeV for two BL Lac-type AGN in the Southern
sky: PKS 2155-304 and PKS 2005-489. The TeV spectrum of the BL Lac object 1ES
2344+514 has also been recently measured by the Whipple collaboration. Using
the results of phenomenological calculations of the SED of the EBL we have
extracted the intrinsic gamma-ray spectra of these blazars. Consequently we
have shown that these spectra can be fitted well by means of a synchrotron self
Compton model.


title:
Turbulent gas motions in galaxy cluster simulations: The role of SPH
  viscosity

abstract:
  Smoothed particle hydrodynamics (SPH) employs an artificial viscosity to
properly capture hydrodynamical shock waves. In its original formulation, the
resulting numerical viscosity is large enough to suppress structure in the
velocity field on scales well above the nominal resolution limit, and to damp
the generation of turbulence by fluid instabilities. This could artificially
suppress random gas motions in the intracluster medium (ICM), which are driven
by infalling structures during the hierarchical structure formation process. We
show that this is indeed the case by analysing results obtained with an SPH
formulation where an individual, time-variable viscosity is used for each
particle (Monaghan 1997). Using test calculations involving strong shocks, we
demonstrate that this scheme captures shocks as well as the original
formulation of SPH, but, in regions away from shocks, the numerical viscosity
is much smaller. In a set of nine high-resolution simulations of cosmological
galaxy cluster formation, we find that this low--viscosity formulation of SPH
produces substantially higher levels of turbulent gas motions in the ICM,
reaching a kinetic energy content in random gas motions (measured within a 1Mpc
cube) of up to 5%-30% of the thermal energy content, depending on cluster mass.
This has also significant effects on radial gas profile. We find a central
flattening of the entropy profile and a reduction of the central gas density in
the low--viscosity scheme. Interestingly, this tends to reduce the differences
seen in SPH and adaptive mesh refinement simulations of cluster formation.
Finally, invoking a model for particle acceleration by MHD waves driven by
turbulence, we find efficient electron acceleration to power diffuse radio
emission.


title: An HI interstellar bubble surrounding WR85 and RCW118

abstract:
  We analyze the distribution of the interstellar matter in the environs of the
Wolf-Rayet star LSS3982 (= WR85, WN6+OB?) linked to the optical ring nebula
RCW118. Our study is based on neutral hydrogen 21cm-line data belonging to the
Southern Galactic Plane Survey (SGPS).
  The analysis of the HI data allowed the identification of a neutral hydrogen
interstellar bubble related to WR 85 and the 25' diameter ring nebula RCW118.
The HI bubble was detected at a systemic velocity of -21.5 km/s, corresponding
to a kinematical distance of 2.8+/-1.1 kpc, compatible with the stellar
distance. The neutral stucture is about 25' in radius or 21+/-8 pc, and is
expanding at 9+/-2 km/s. The associated ionized and neutral masses amount to
3000 Mo. The CO emission distribution depicts a region lacking CO coincident in
position and velocity with the HI structure. The 9'.3 diameter inner optical
nebula appears to be related to the approaching part of the neutral atomic
shell. The HI void and shell are the neutral gas counterparts of the optical
bubble and have very probably originated in the action of the strong stellar
wind of the central star during the O-type and WR phases on the surrounding
interstellar medium. The HI bubble appears to be in the momentun conserving
stage.


title:
Perturbations of the Quintom Models of Dark Energy and the Effects on
  Observations

abstract:
  We study in this paper the perturbations of the quintom dark energy model and
the effects of quintom perturbations on the current observations. Quintom
describes a scenario of dark energy where the equation of state gets across the
cosmological constant boundary $w = -1$ during evolution. We present a new
method to show that the conventional dark energy models based on single
k-essence field and perfect fluid cannot act as quintom due to the
singularities and classical instabilities of perturbations around $w = -1$. One
needs to add extra degrees of freedom for successful quintom model buildings.
There are no singularities or classical instabilities in perturbations of
realistic quintom models and they are potentially distinguishable from the
cosmological constant. Basing on the realistic quintom models in this paper we
provide one way to include the perturbations for dark energy models with
parametrized equation of state across -1. Compare with those assuming no dark
energy perturbations, we find that the parameter space which allows the
equation of state to get across -1 will be enlarged in general when including
the perturbations.


title: UHECR Composition Measurements Using the HiRes-II Detector

abstract:
  While stereo measurements of extensive air showers allow a more precise
determination of the depth of shower maximum and hence the composition of
UHECR's, monocular measurements allow one to go much lower in energy. Since the
composition of UHECR seems to constant throughout the HiRes stereo energy range
but changing just below it, this is not a trivial lowering of the energy
threshold. We fit the observed Xmax distribution to a combination of expected
proton and iron Xmax distributions, using two different interaction models, to
determine the relative fraction of light and heavy components throughout the
HiRes monocular energy range. Using a two component fit allows both the mean
Xmax and the width of the Xmax distribution to contribute composition
measurement and allows us to deal with the Xmax acceptance bias caused by
limited elevation coverage. An updated analysis from a larger data set will be
presented in Pune.


title: Fitting the HiRes Spectra

abstract:
  We fit the HiRes ultra-high energy cosmic ray (UHECR) spectrum measurements
with broken power laws in order to identify features. These fits find the
previously observed feature known as the Ankle at 10**18.5 eV, as well as
evidence for a suppression at higher energies, above 10**19.8 eV. We use the
integral spectrum and the E_1/2 test to identify this high energy suppression
with the GZK suppression. Finally, we use a model of uniformly distributed
extragalactic proton sources together with a phenomenological model of the
galactic cosmic ray spectrum to compare the HiRes spectra to what should be
expected from the GZK suppression, and to measure how the extragalactic sources
must evolve and what the input spectral slope must be to fit the HiRes data.
Fits using updated spectra will be presented in Pune.


title:
Comparison of UHE Composition Measurements by Fly's Eye,
  HiRes-prototype/MIA and Stereo HiRes Experiments

abstract:
  We compare the elongation rate and Xmax distributions for three
air-fluorescence experiments: Stereo Fly's Eye, HiRes/MIA, and HiRes. A shift
of 13 gm/cm^3 of the stereo Fly's Eye data, well within the quoted systematic
errors, brings the elongation rates and the Xmax distributions of all three
experiments into reasonable agreement. We explore the implications of this
combined dataset ranging from 10^17 eV to near 10^20 eV.


title:
Validation of the Real and Simulated Data of the Pierre Auger
  Fluorescence Telescopes

abstract:
  The fluorescence detector (FD) of the Pierre Auger Observatory is currently
operating 18 fluorescence telescopes of the 24 that will be employed in the
completed detector. These telescopes, grouped in 4 eyes each consisting of 6
telescopes, measure the longitudinal profile of cosmic ray showers with a 14%
duty cycle. The reconstruction capability and triggering efficiency have been
studied using a complete simulation and reconstruction production chain,
employing both simulated CORSIKA showers and parameterised Gaisser-Hillas
profiles. The propagation through the atmosphere and the detector response are
taken into account and simulated in detail. These simulated data have been
generated in a preliminary analysis using the method of importance sampling to
efficiently cover the energy region of 0.3 - 300 EeV, various shower geometries
and impact points and different primary particles. The distributions of
observables have then been investigated in both real and simulated data,
facilitating the validation of the reconstruction and simulation software.
Comparisons of real and simulated data are discussed and used to assess their
impact on the data analysis.


title: Measuring the evolution of the most stable optical clock G 117-B15A

abstract:
  We report our measurement of the rate of change of period with time dP/dt for
the 215 s periodicity in the pulsating white dwarf G 117-B15A, the most stable
optical clock known. After 31 years of observations, we have finally obtained a
4 sigma measurement dP/dt_observed = (4.27 +/- 0.80) x 10^{-15} s/s. Taking
into account the proper-motion effect of dP/dt_pm = (7.0 +/- 2.0) x 10^{-16}
s/s, we obtain a rate of change of period with time of dP/dt = (3.57 +/- 0.82)
x 10^{-15} s/s. This value is consistent with the cooling rate in our white
dwarf models only for cores of C or C/O. With the refinement of the models, the
observed rate of period change can be used to accurately measure the ratio of
C/O in the core of the white dwarf.


title:
The GRB 030329 host: a blue low metallicity subluminous galaxy with
  intense star formation

abstract:
  We present broad band photometry and spectroscopic observations of the host
galaxy of GRB 030329. Analysis of the spectral emission lines shows that the
host is likely a low metallicity galaxy (Z~0.004). The spectral energy
distribution (SED) constructed with the photometric points has been fitted
using synthetic and observational templates. The best SED fit is obtained with
a starburst template with an age of ~150 Myr and an extinction Av~0.6. We find
that the GRB 030329 host galaxy is a subluminous galaxy (L~0.016 L*) with a
stellar mass of >~10^8 Mo. Three independent diagnostics, based on the
restframe UV continuum, the [OII], and the Balmer emission lines, provide a
consistent unextincted star formation rate of ~0.6 Mo yr^-1, implying a high
unextincted specific star formation rate (~34 Mo yr^-1 (L/L*)^-1). We estimate
that the unextincted specific star formation rate of the GRB 030329 host is
higher than ~93.5% of the galaxies at a similar redshift.


title:
The extremely asymmetric radio structure of the z=3.1 radio galaxy B3
  J2330+3927

abstract:
  We report on 1.7 and 5.0 GHz observations of the z=3.087 radio galaxy B3
J2330+3927, using the Very Long Baseline Array (VLBA), and archival 1.4 and 8.4
GHz Very Large Array (VLA) data. Our VLBA data identify a compact, flat
spectrum (\alpha_{1.7 GHz}^{5 GHz} = -0.2 +/- 0.1; S_\nu ~ \nu^\alpha) radio
component as the core. The VLA images show that the fraction of core emission
is very large (f_c \approx 0.5 at 8.4 GHz), and reveal a previously undetected,
very faint counterjet, implying a radio lobe flux density ratio R >= 11 and a
radio lobe distance ratio Q \approx 1.9. Those values are much more common in
quasars than in radio galaxies, but the optical/near-IR spectra show a clear
type II AGN for B3 J2330+3927, confirming that it is indeed a radio galaxy.
Unlike all other radio galaxies, the bright Ly-\alpha emitting gas is located
towards the furthest radio arm. We argue against environmental and relativistic
beaming effects being the cause of the observed asymmetry, and suggest this
source has intrinsically asymmetric radio jets. If this is the case, B3
J2330+3927 is the first example of such a source at high redshift, and seems to
be difficult to reconcile with the unified model, which explains the
differences between quasars and radio galaxies as being due to orientation
effects.


title: Discovery of fourteen new ZZ Cetis with SOAR

abstract:
  We report the discovery of fourteen new ZZ Cetis with the 4.1m Southern
Astrophysical Research telescope, at Cerro Pachon, in Chile. The candidates
were selected from the SDSS (Sloan Digital Sky Survey) DA white dwarf stars
with Teff obtained from the optical spectra fit, inside the ZZ Ceti instability
strip. Considering these stars are multi-periodic pulsators and the pulsations
propagate to the nucleus of the star, they carry information on the structure
of the star and evolution of the progenitors. The ZZ Cetis discovered till 2003
are mainly within 100 pc from the Sun, and probe only the solar vicinity. The
recently discovered ones, and those reported here, may sample a distinct
population as they were selected mainly perpendicular to the galactic disk and
cover a distance up to ~400pc.


title:
Cloud Structure and Physical Conditions in Star-Forming Regions from
  Optical Observations. II. Analysis

abstract:
  To complement the optical absorption-line survey of diffuse molecular gas in
Paper I, we obtained and analyzed far ultraviolet H$_2$ and CO data on lines of
sight toward stars in Cep OB2 and Cep OB3. Possible correlations between column
densities of different species for individual velocity components, not total
columns along a line of sight as in the past, were examined and were
interpreted in terms of cloud structure. The analysis reveals that there are
two kinds of CH in diffuse molecular gas: CN-like CH and CH$^+$-like CH.
Evidence is provided that CO is also associated with CN in diffuse molecular
clouds. Different species are distributed according to gas density in the
diffuse molecular gas. Both calcium and potassium may be depleted onto grains
in high density gas, but with different dependences on local gas density. Gas
densities for components where CN was detected were inferred from a chemical
model. Analysis of cloud structure indicates that our data are generally
consistent with the large-scale structure suggested by maps of CO
millimeter-wave emission. On small scales, the gas density is seen to vary by
factors greater than 5.0 over scales of $\sim$ 10,000 AU. The relationships
between column densities of CO and CH with that of H$_2$ along a line of sight
show similar slopes for the gas toward Cep OB2 and OB3, but the CO/H$_2$ and
CH/H$_2$ ratios tend to differ which we ascribe to variation in average density
along the line of sight.


title: Planetary migration

abstract:
  Gravitational torques between a planet and gas in the protoplanetary disk
result in orbital migration of the planet, and are likely to play an important
role in the formation and early evolution of planetary systems. For masses
comparable to those of observed giant extrasolar planets, the interaction with
the disk is strong enough to form a gap, leading to coupled evolution of the
planet and disk on a viscous time scale (Type II migration). Both the existence
of hot Jupiters, and the statistical distribution of observed orbital radii,
are consistent with an important role for Type II migration in the history of
currently observed systems. We discuss the possibility of improving constraints
on migration by including information on the host stars' metallicity, and note
that migration could also form a population of massive planets at large orbital
radii that may be indirectly detected via their influence on debris disks. For
lower mass planets with masses of the order of that of the Earth, surface
density perturbations created by the planet are small, and migration in a
laminar disk is driven by an intrinsic and apparently robust asymmetry between
interior and exterior torques. Analytic and numerical calculations of this Type
I migration are in reasonable accord, and predict rapid orbital decay during
the final stages of the formation of giant planet cores. The difficulty of
reconciling Type I migration with giant planet formation may signal basic
errors in our understanding of protoplanetary disks, core accretion, or both.
We discuss physical effects that might alter Type I behavior, in particular the
possibility that for sufficiently low masses turbulent fluctuations in the gas
surface density dominate the torque, leading to random walk migration of very
low mass bodies.


title:
Hubble Space Telescope Imaging of the Ultracompact Blue Dwarf Galaxy HS
  0822+3542: An Assembling Galaxy in a Local Void?

abstract:
  We present deep U, narrow-V, and I-band images of the ultracompact blue dwarf
galaxy HS 0822+3542, obtained with the Advanced Camera for Surveys / High
Resolution Channel of the Hubble Space Telescope. This object is extremely
metal-poor (12 + log(O/H) = 7.45) and resides in a nearby void. The images
resolve it into two physically separate components that were previously
described as star clusters in a single galaxy. The primary component is only
\~100 pc in maximum extent, and consists of starburst region surrounded by a
ring-like structure of relatively redder stars. The secondary component is ~50
pc in size and lies at a projected distance of ~80 pc away from the primary,
and is also actively star-forming. We estimate masses ~10^7 M(sol) and ~10^6
M(sol) for the two components, based on their luminosities, with an associated
dynamical timescale for the system of a few Myr. This timescale and the
structure of the components suggests that a collision between them triggered
their starbursts. The spectral energy distributions of both components can be
fitted by the combination of recent (few Myr old) starburst and an evolved
(several Gyr old) underlying stellar population, similar to larger blue compact
dwarf galaxies. This indicates that despite its metal deficiency the object is
not forming its first generation of stars. However, the small sizes and masses
of the two components suggests that HS 0822+3542 represents a dwarf galaxy in
the process of assembling from clumps of stars intermediate in size between
globular clusters and objects previously classified as galaxies. Its relatively
high ratio of neutral gas mass to stellar mass (~1) and high specific star
formation rate, log(SFR/M(sol) = -9.2, suggests that it is still converting
much of its gas to stars.


title:
A Measurement of the Angular Power Spectrum of the CMB Temperature
  Anisotropy from the 2003 Flight of Boomerang

abstract:
  We report on observations of the Cosmic Microwave Background (CMB) obtained
during the January 2003 flight of Boomerang . These results are derived from
195 hours of observation with four 145 GHz Polarization Sensitive Bolometer
(PSB) pairs, identical in design to the four 143 GHz Planck HFI polarized
pixels. The data include 75 hours of observations distributed over 1.84% of the
sky with an additional 120 hours concentrated on the central portion of the
field, itself representing 0.22% of the full sky. From these data we derive an
estimate of the angular power spectrum of temperature fluctuations of the CMB
in 24 bands over the multipole range (50 < l < 1500). A series of features,
consistent with those expected from acoustic oscillations in the primordial
photon-baryon fluid, are clearly evident in the power spectrum, as is the
exponential damping of power on scales smaller than the photon mean free path
at the epoch of last scattering (l > 900). As a consistency check, the
collaboration has performed two fully independent analyses of the time ordered
data, which are found to be in excellent agreement.


title: Spiral waves and the secondary in the novalike variable, V3885 Sgr

abstract:
  We present seven nights' blue spectroscopy of the novalike variable star,
V3885 Sgr. The line spectrum shows a typical combination of broad absorption
and emission in H gamma and H beta and He I, which is associated with the
accretion disk. We also observe anti-phased narrow emission, which we attribute
to irradiation of the secondary star. The He II 4686 and N III--C III--C IV
emission lines are devoid of structure and are most likely formed in an
outflow. We measure radial velocity shifts in the absorption and emission
lines, from which we fit an orbital period of 4.97126+/-0.00036h. From the
velocity semi-amplitudes of the disk and companion star, we are able to
constrain the binary mass ratio to q>0.7.
  The phase-folded spectra provide dense coverage of the entire orbital cycle.
Doppler tomograms of the hydrogen and He I lines reveal spiral structure in the
accretion disk and the irradiated donor star. We believe this is the first
unambiguous detection of spiral waves in a novalike variable.


title:
Extending the Search for Counterrotating Gas and Stars in Galaxies: A
  Study of Late-Type Dwarfs

abstract:
  In a previous study on gas-stellar counterrotation for a large sample of E/S0
and spiral galaxies (Kannappan & Fabricant 2001), two dwarf irregular galaxies
were included, of which one was tentatively identified as a counterrotator.
Here we extend the search for counterrotation to include 10 more
irregular/spiral dwarf galaxies. We find that all systems with well defined gas
and stellar rotation show kinematics consistent with co-rotation. However, we
see evidence of decoupled gas and stellar kinematics in >~ 50% of the sample,
possibly reflecting minor interactions too small to create large-scale
gas-stellar counterrotation.


title: Neutron star matter equation of state and gravitational wave emission

abstract:
  The EOS of strongly interacting matter at densities ten to fifteen orders of
magnitude larger than the typical density of terrestrial macroscopic objects
determines a number of neutron star properties, including the pattern of
gravitational waves emitted following the excitation of nonradial oscillation
modes. This paper reviews some of the approaches employed to model neutron star
matter, as well as the prospects for obtaining new insights from the
experimental study of gravitational waves emitted by neutron stars.


title: Long period variables in 47 Tuc: direct evidence for lost mass

abstract:
  We have identified 22 new variable red giants in 47 Tuc and determined
periods for another 8 previously known variables. All red giants redder than
V-I_c=1.8 are variable at the limits of our detection threshold, which
corresponds to delta V ~ 0.1 mag. This colour limit corresponds to a luminosity
log L/L_sun=3.15 and it is considerably below the tip of the RGB at log
L/L_sun=3.35. Linear non-adiabatic models without mass loss on the giant branch
can not reproduce the observed PL laws for the low amplitude pulsators. Models
that have undergone mass loss do reproduce the observed PL relations and they
show that mass loss of the order of 0.3 M_sun occurs along the RGB and AGB. The
linear pulsation periods do not agree well with the observed periods of the
large amplitude Mira variables, which pulsate in the fundamental mode. The
solution to this problem appears to be that the nonlinear pulsation periods in
these low mass stars are considerably shorter than the linear pulsation periods
due to a rearrangement of stellar structure caused by the pulsation. Both
observations and theory show that stars evolve up the RGB and first part of the
AGB pulsating in low order overtone modes, then switch to fundamental mode at
high luminosities.


title: Extended emission around GPS radio sources

abstract:
  Extended radio emission detected around a sample of GHz Peaked Spectrum (GPS)
radio sources is discussed. Evidence for extended emission which is related to
the GPS source is found in 6 objects out of 33. Three objects are associated
with quasars with core-jet pc-scale morphology, and three are identified with
galaxies with symmetric (CSO) radio morphology. We conclude that the core-jet
GPS quasars are likely to be beamed objects with a continuous supply of energy
from the core to the kpc scale. It is also possible that low surface brightness
extended radio emission is present in other GPS quasars but the emission is
below our detection limit due to the high redshifts of the objects. On the
other hand, the CSO/galaxies with extended large scale emission may be
rejuvenated sources where the extended emission is the relic of previous
activity. In general, the presence of large scale emission associated with GPS
galaxies is uncommon, suggesting that in the context of the recurrent activity
model, the time scale between subsequent bursts is in general longer than the
radiative lifetime of the radio emission from the earlier activity.


title: Do cosmic rays drive jets?

abstract:
  A sudden release of high energy cosmic rays at the centre of a wind
sustaining a spiral magnetic field produces cavities of low density and low
magnetic field along the axis. The trajectories of high energy cosmic rays are
focussed onto the axis, and lower energy cosmic rays and thermal plasma can
escape through the cavities. This may explain the jets often seen in accretion
systems and elsewhere.


title: Eclipsing Light-Curve Asymmetry for Black-Hole Accretion Flows

abstract:
  We propose an eclipsing light-curve diagnosis for black-hole accretion flows.
When emission from an inner accretion disk around a black hole is occulted by a
companion star, the observed light curve becomes asymmetric at ingress and
egress on a time scale of 0.1-1 seconds. This light-curve analysis provides a
means of verifying the relativistic properties of the accretion flow, based on
the special/general relativistic effects of black holes. The ``skewness'' for
the eclipsing light curve of a thin disk is $\sim 0.08$, whereas that of a slim
disk is $\sim 0$, since the innermost part is self-occulted by the disk's outer
rim.


title: The Progenitor of SN 2005cs in the Whirlpool Galaxy

abstract:
  The progenitor of SN 2005cs, in the galaxy M51, is identified in
pre-explosion HST ACS WFC imaging. Differential astrometry, with post-explosion
ACS HRC F555W images, permitted the identification of the progenitor with an
accuracy of 0.006". The progenitor was detected in the F814W pre-explosion
image with I=23.3+/-0.2, but was below the detection thresholds of the F435W
and F555W images, with B<24.8 and V<25 at 5-sigma. Limits were also placed on
the U and R band fluxes of the progenitor from pre-explosion HST WFPC2 F336W
and F675W images. Deep images in the infra-red from NIRI on the Gemini-North
telescope were taken 2 months prior to explosion, but the progenitor is not
clearly detected on these. The upper limits for the JHK magnitudes of the
progenitor were J<21.9,H<21.1 and K<20.7. Despite having a detection in only
one band, a restrictive spectral energy distribution of the progenitor star can
be constructed and a robust case is made that the progenitor was a red
supergiant with spectral type between mid-K to late-M. The spectral energy
distribution allows a region in the theoretical HR diagram to be determined
which must contain the progenitor star. The initial mass of the star is
constrained to be M(ZAMS)=9+3/-2 M_solar, which is very similar to the
identified progenitor of the type II-P SN 2003gd, and also consistent with
upper mass limits placed on five other similar SNe. The upper limit in the deep
K-band image is significant in that it allows us to rule out the possibility
that the progenitor was a significantly higher mass object enshrouded in a dust
cocoon before core-collapse. This is further evidence that the trend for type
II-P SNe to arise in low to moderate mass red supergiants is real.


title: Cosmological Parameters from the 2003 flight of BOOMERANG

abstract:
  We present the cosmological parameters from the CMB intensity and
polarization power spectra of the 2003 Antarctic flight of the BOOMERANG
telescope. The BOOMERANG data alone constrains the parameters of the
$\Lambda$CDM model remarkably well and is consistent with constraints from a
multi-experiment combined CMB data set. We add LSS data from the 2dF and SDSS
redshift surveys to the combined CMB data set and test several extensions to
the standard model including: running of the spectral index, curvature, tensor
modes, the effect of massive neutrinos, and an effective equation of state for
dark energy. We also include an analysis of constraints to a model which allows
a CDM isocurvature admixture.


title: The population of BzK selected ULIRGs at z~2

abstract:
  We investigate the multi-wavelength emission of BzK selected star forming
galaxies at z~2 in the Great Observatories Origins Deep Survey (GOODS) North
region. Most (82%) of the sources are individually detected at 24um in the
Spitzer MIPS imaging, and one fourth (26%) in the VLA radio data. Significant
detections of the individually undetected objects are obtained through stacking
in the radio, submm and X-ray domains. The typical star forming galaxy with
stellar mass ~10^{11}Mo at z=2 is an Ultra-luminous Infrared Galaxy (ULIRG),
with L_IR ~ 1-2x10^{12}Lo and star formation rate SFR 200-300Mo/yr, implying a
comoving density of ULIRGs at z=2 at least 3 orders of magnitude above the
local one. SFRs derived from the reddening corrected UV luminosities agree
well, on average, with the longer wavelength estimates. The high 24um detection
rate suggests a relatively large duty cycle for the BzK star forming phase,
consistently with the available independent measurements of the space density
of passively evolving galaxies at z>1.4. If the IMF at z=2 is similar to the
local one, and in particular is not a top-heavy IMF, this suggests that a
substantial fraction of the high mass tail (>10^{11}Mo) of the galaxy stellar
mass function was completed by z~1.4.


title: Are radio pulsars progenitors of AXPs and SGRs?

abstract:
  Possibility of realization of scenario for the AXPs and SGRs origins from
radio pulsars, which were undergone frequent and strong glitches, was analyzed.
It is shown that the characteristics of such pulsars - the possible progenitors
of AXPs and SGRs - their association with supernova remnants (SNRs) and
evolution on the $P - \dot P$ diagram, taking into account their real ages,
conflict with offered scenario.


title: Sunyaev-Zeldovich Cluster Counts as a Probe of Intra-Supercluster Gas

abstract:
  X-ray background surveys indicate the likely presence of diffuse warm gas in
the Local Super Cluster (LSC), in accord with expectations from hydrodynamical
simulations. We assess several other manifestations of warm LSC gas; these
include anisotropy in the spatial pattern of cluster Sunyaev-Zeldovich (S-Z)
counts, its impact on the CMB temperature power spectrum at the lowest
multipoles, and implications on measurements of the S-Z effect in and around
the Virgo cluster.


title:
A measurement of the polarization-temperature angular cross power
  spectrum of the Cosmic Microwave Background from the 2003 flight of BOOMERANG

abstract:
  We present a measurement of the temperature-polarization angular cross power
spectrum, <TE>, of the Cosmic Microwave Background. The result is based on
$\sim 200$ hours of data from 8 polarization sensitive bolometers operating at
145 GHz during the 2003 flight of BOOMERANG. We detect a significant <TE>
correlation in the $\ell$-range between 50 and 950 with a statistical
significance > 3.5 sigma. Contamination by polarized foreground emission and
systematic effects are negligible in comparison with statistical uncertainty.
The spectrum is consistent with previous detections and with the "concordance
model" that assumes adiabatic initial conditions. This is the first measurement
of <TE> using bolometric detectors.


title:
The complex velocity distribution of galaxies in Abell 1689:
  implications for mass modelling

abstract:
  The Abell 1689 galaxy cluster has recently become a subject of intensive
study. Thanks to its intermediate redshift (z=0.183) its mass distribution can
be reconstructed using numerous methods including gravitational lensing, galaxy
kinematics and X-ray imaging. The methods used to yield conflicting mass
estimates in the past and recently the cluster mass distribution has been
claimed to be in conflict with standard CDM scenarios due to rather large
concentration and steep mass profile obtained from detailed studies of
Broadhurst et al. using lensing. By studying in detail the kinematics of about
200 galaxies with measured redshifts in the vicinity of the cluster we show
that the cluster is probably surrounded by a few structures, quite distant from
each other, but aligned along the line of sight. We support our arguments by
referring to cosmological N-body simulations and showing explicitly that
distant, non-interacting haloes can produce entangled multi-peak line-of-sight
velocity distributions similar to that in A1689. We conclude that it is
difficult to estimate the cluster mass reliably from galaxy kinematics, but the
value we obtain after applying a simple cut-off in velocity agrees roughly with
the mass estimated from lensing. The complicated mass distribution around the
cluster may however increase the uncertainty in the determination of the
density profile shape obtained with weak lensing.


title:
Instrument, Method, Brightness and Polarization Maps from the 2003
  flight of BOOMERanG

abstract:
  We present the BOOMERanG-03 experiment and maps of the Stokes parameters I,
Q, U of the microwave sky obtained during a 14 day balloon flight in 2003.
Three regions of the southern sky were surveyed: a deep survey (~ 90 square
degrees) and a shallow survey (~ 750 square degrees) at high Galactic latitudes
(both centered at RA ~ 5.5 h, dec ~ -45 deg) and a survey of ~ 300 square
degrees across the Galactic plane at RA ~ 9.1 h, dec ~ -47 deg. All three
surveys were carried out in three wide frequency bands centered at 145, 245 and
345 GHz, with an angular resolution of ~ 10'. The 145 GHz maps of Stokes I are
dominated by Cosmic Microwave Background (CMB) temperature anisotropy, which is
mapped with high signal to noise ratio. The measured anisotropy pattern is
consistent with the pattern measured in the same region by BOOMERanG-98 and by
WMAP. The 145 GHz maps of Stokes Q and U provide a robust statistical detection
of polarization of the CMB when subjected to a power spectrum analysis. This
amplitude of the polarization is consistent with that of the CMB in the
$\Lambda$CDM cosmological scenario. At 145 GHz, in the CMB surveys, the
intensity and polarization of the astrophysical foregrounds are found to be
negligible with respect to the cosmological signal. At 245 and 345 GHz we
detect ISD emission correlated to the 3000 GHz IRAS/DIRBE maps, and give upper
limits for any other non-CMB component. We also present intensity maps of the
surveyed section of the Galactic plane. These are compared to monitors of
different interstellar components, showing that a variety of emission
mechanisms is present in that region.


title: Metallicity effect in multi-dimensional SNIa nucleosynthesis

abstract:
  We investigate the metallicity effect (measured by the original 22Ne content)
on the detailed nucleosynthetic yields for 3D hydrodynamical simulations of the
thermonuclear burning phase in SNe Ia. Calculations are based on post-processes
of the ejecta, using passively advected tracer particles, as explained in
details by Travaglio et al.(2004). The nuclear reaction network employed in
computing the explosive nucleosynthesis contains 383 nuclear species. For this
work we use the high resolution multi-point ignition (bubbles) model b30_3d_768
(Travaglio et al.2004 for the solar metallicity case), and we cover a
metallicity range between 0.1xZ_sun up to 3xZ_sun. We find a linear dependence
of the 56Ni mass ejected on the progenitor's metallicity, with a variation in
the 56Ni mass of ~25% in the metallicity range explored. Moreover, the largest
variation in 56Ni occurs at metallicity greater than solar. Almost no
variations are shown in the unburned material 12C and 16O. The largest
metallicity effect is seen in the alpha-elements. Finally, implications for the
observed scatter in the peak luminosities of SNe Ia are also discussed.


title:
ULTRACAM observations of the black hole X-ray transient XTE J1118+480 in
  quiescence

abstract:
  We present high time-resolution multicolour observations of the quiescent
soft X-ray transient XTE J1118+480 obtained with ULTRACAM. Superimposed on the
double-humped continuum g' and i'-band lightcurves are rapid flare events which
typically last a few minutes. The power density spectrum of the lightcurves can
be described by a broken power-law model with a break frequency at ~2 mHz or a
power-law model plus a broad quasi-periodic oscillation (QPO) at ~2 mHz. In the
context of the cellular-automaton we estimate the size of the quiescent
advection-dominated flow (ADAF) region to be ~10^4 Schwarzschild radii, similar
to that observed in other quiescent black hole X-ray transients, suggesting the
same underlying physics. The similarites between the low/hard and quiescent
state PDS suggest a similar origin for the optical and X-ray variability, most
likely from regions at/near the ADAF.


title: Imaging Earth-like planets with Extremely Large Telescopes

abstract:
  We investigate the possiblity to detect Earth-like planets, in the visible
and the near infrared domains, with ground based Extremely Large Telescopes
equipped with adaptive systems capable of providing high Strehl ratios. From a
detailed analysis of the speckle noise, we derive analytical expressions of the
signal to noise ratio on the planet flux, for direct and differential imaging,
in the presence of the speckle noise and the photon noise of the residual
stellar halo. We find that a 100m telescope would detect an Earth at a distance
of 10pc, with a signal to noise ratio of 5, in an integration time of 12 hours.
This requires to control the instrumental aberrations with a precision better
than 1 nanometer rms, and to reach an image dynamics of $1.2{\rm x}10^{6}$ at
$0\farcs 1$ radius. Under the same conditions, a telescope of 30m would require
a dynamics of $1.3{\rm x}10^{7}$ for a positive detection


title: A jet-induced outflow of warm gas in 3C 293

abstract:
  Using long slit emission-line spectra we detect a fast outflow of ionized
gas, with velocities up to 1000 km/s, in the nearby powerful radio galaxy 3C
293 (z = 0.045). The fast outflow is located about 1 kpc east of the nucleus,
in a region of enhanced radio emission due to the presence of a distorted radio
jet. We present results that indicate that this fast outflow is caused by a
jet-ISM interaction. The kinematics of the outflowing ionized gas are very
similar to those of a fast outflow of neutral hydrogen gas in this galaxy,
suggesting that both outflows are the result of the same driving mechanism.
While the mass of the outflowing ionized gas is about 1 x 10e5 M_sun, the total
HI mass involved in the neutral outflow is about 100 times higher (10e7 M_sun).
This shows that, despite the high energies that must be involved in driving the
outflow, most of the gas remains, or becomes again, neutral. Other outflows of
ionized gas, although not as pronounced as in the region of the enhanced radio
emission, are also seen in various other regions along the axis of the inner
radio jets. The regular kinematics of the emission-line gas along the major
axis of the host galaxy reveal a rotating ionized gas disk 30 kpc in extent.


title: A Measurement of the CMB <EE> Spectrum from the 2003 Flight of BOOMERANG

abstract:
  We report measurements of the CMB polarization power spectra from the January
2003 Antarctic flight of BOOMERANG. The primary results come from six days of
observation of a patch covering 0.22% of the sky centered near R.A. = 82.5
deg., Dec= -45 deg. The observations were made using four pairs of polarization
sensitive bolometers operating in bands centered at 145 GHz. Using two
independent analysis pipelines, we measure a non-zero <EE> signal in the range
100< l <1000 with a significance 4.8-sigma, a 2-sigma upper limit of 8.6 uK^2
for any <BB> contribution, and a 2-sigma upper limit of 7.0 uK^2 for the <EB>
spectrum. Estimates of foreground intensity fluctuations and the non-detection
of <BB> and <EB> signals rule out any significant contribution from galactic
foregrounds. The results are consistent with a Lambda-CDM cosmology seeded by
adiabatic perturbations. We note that this is the first detection of CMB
polarization with bolometric detectors.


title: Swift panchromatic observations of the bright gamma-ray burst GRB050525a

abstract:
  The bright gamma-ray burst GRB050525a has been detected with the Swift
observatory, providing unique multiwavelength coverage from the very earliest
phases of the burst. The X-ray and optical/UV afterglow decay light curves both
exhibit a steeper slope ~0.15 days after the burst, indicative of a jet break.
This jet break time combined with the total gamma-ray energy of the burst
constrains the opening angle of the jet to be 3.2 degrees. We derive an
empirical `time-lag' redshift from the BAT data of z_hat = 0.69 +/- 0.02, in
good agreement with the spectroscopic redshift of 0.61.
  Prior to the jet break, the X-ray data can be modelled by a simple power law
with index alpha = -1.2. However after 300 s the X-ray flux brightens by about
30% compared to the power-law fit. The optical/UV data have a more complex
decay, with evidence of a rapidly falling reverse shock component that
dominates in the first minute or so, giving way to a flatter forward shock
component at later times.
  The multiwavelength X-ray/UV/Optical spectrum of the afterglow shows evidence
for migration of the electron cooling frequency through the optical range
within 25000 s. The measured temporal decay and spectral indices in the X-ray
and optical/UV regimes compare favourably with the standard fireball model for
Gamma-ray bursts assuming expansion into a constant density interstellar
medium.


title:
Reconstruction of showers in the calorimeter during the first flight of
  the CREAM balloon experiment

abstract:
  The Cosmic Ray Energetics And Mass (CREAM) balloon-borne experiment was first
flown from Antarctica in December 2004. The instrument includes a
tungsten/Sci-Fi calorimeter preceded by a graphite target (~0.5 interaction
length and ~1 radiation length) where a hadronic shower is initiated by the
inelastic interaction of the incoming nucleus. The fine granularity (1 cm) of
the 20 radiation length calorimeter allows the imaging of the narrow
electromagnetic core of the shower and the determination of the direction of
the incident particle. Preliminary results, from the flight data, on the shower
reconstruction capability of the instrument and on the observed shower
properties are presented.


title:
Coverage and large scale anisotropies estimation methods for the Pierre
  Auger Observatory

abstract:
  When searching for anisotropies in the arrival directions of Ultra High
Energy Cosmic Rays, one must estimate the number of events expected in each
direction of the sky in the case of a perfect isotropy. We present in this
article a new method, developed for the Auger Observatory, based on a smooth
estimate of the zenith angle distribution obtained from the data itself (which
is essentially unchanged in the case of the presence of a large scale
anisotropy pattern). We also study the sensitivity of several methods to detect
large-scale anisotropies in the cosmic ray arrival direction distribution :
Rayleigh analysis, dipole fitting and angular power spectrum estimation.


title:
The nature of the X-ray halo of the plerion G21.5-0.9 unveiled by
  XMM-Newton and Chandra

abstract:
  The nature of the radio-quiet X-ray halo around the plerionic SNR G21.5-0.9
is under debate. On the basis of spatial and spectral analysis of a large
Chandra and XMM-Newton dataset of this source, we have developed a
self-consistent scenario which explains all the observational features. We
found that the halo is composed by diffuse extended emission due to dust
scattering of X-rays from the plerion, by a bright limb which traces particle
acceleration in the fast forward shock of the remnant, and by a bright spot
(the ``North Spur'') which may be a knot of ejecta in adiabatic expansion. By
applying a model of interaction between the PWN, the SNR and supernova
environment, we argue that G21.5-0.9 progenitor may be of Type IIP or Ib/Ic,
and that the remnant may be young (200-1000 yr).


title: Keck Deep Fields. II. The UV Galaxy Luminosity Function at z~4, 3, and 2

abstract:
  We use very deep UGRI multi-field imaging obtained at the Keck telescope to
study the evolution of the rest-frame 1700A galaxy luminosity function as the
Universe doubles its age from z~4 to z~2. The depth of our imaging allows us to
constrain the faint end of the luminosity function reaching M_1700A ~ -18.5 at
z~3 (equivalent to ~1M_sun/yr) accounting for both N^1/2 uncertainty in the
number of galaxies and for cosmic variance. We carefully examine many potential
sources of systematic bias in our LF measurements before drawing the following
conclusions. We find that the luminosity function of Lyman Break Galaxies
evolves with time and that this evolution is likely differential with
luminosity. The result is best constrained between the epochs at z~4 and z~3,
where we find that the number density of sub-L* galaxies increases with time by
at least a factor of 2.3 (11sigma statistical confidence); while the faint end
of the LF evolves, the bright end appears to remain virtually unchanged,
indicating that there may be differential, luminosity-dependent evolution
significant at the 97% level. Potential systematic biases restric our ability
to draw strong conclusions about continued evolution of the luminosity function
to lower redshifts, z~2.2 and z~1.7, but, nevertheless, it appears certain that
the number density of z~2.2 galaxies at all luminosities we studied,
-22<M_1700A<-18, is at least as high as that of their counterparts at z~3.
While it is not yet clear what mechanism underlies the observed evolution, the
fact that this evolution is differential with luminosity opens up new avenues
of improving our understanding of how galaxies form and evolve at high
redshift.


title: The Hypervelocity Star SDSS J090745.0+024507 is a Short-Period Variable

abstract:
  We present high-precision photometry of the hypervelocity star SDSS
J090745.0+024507 (HVS), which has a Galactic rest-frame radial velocity of
v=709 km/s, and so has likely been ejected from the supermassive black hole in
the Galactic center. Our data were obtained on two nights using the MMT 6.5m
telescope, and is supplemented by lower precision photometry obtained on four
nights using the FLWO 1.2m telescope. The high-precision photometry indicates
that the HVS is a short-period, low-amplitude variable, with period P=0.2-2
days and amplitude A = 2-10%. Together with the known effective temperature of
T_eff ~ 10,500 K (spectral type B9), this variability implies that the HVS is a
member of the class of slowly pulsating B-type main sequence stars, thus
resolving the previously-reported two-fold degeneracy in the luminosity and
distance of the star. The HVS has a heliocentric distance of 71 kpc, and an age
of ~0.35 Gyr. The time of ejection from the center of the Galaxy is < 100 Myr,
and thus the existence of the OS constitutes observational evidence of a
population of young stars in the proximity of the central supermassive black
hole ~0.1 Gyr ago. It is possible that the HVS was a member of a binary that
was tidally disrupted by the central black hole; we discuss constraints on the
properties of the companion's orbit.


title:
Differential Microlensing of the Continuum and Broad Emission Lines in
  SDSS J0924+0219, the Most Anomalous Lensed Quasar

abstract:
  SDSS J0924+0219 is the most glaring example of a gravitational lens with
anomalous flux ratios: optical broad-band photometry shows image D to be a
factor of 12 fainter than expected for smooth lens potentials. We report
spectroscopy showing that the anomaly is present in the broad emission line
flux ratios as well. There are differences between the emission line and
continuum flux ratios: the A/D ratio is 10 in the broad Lyman-alpha line and 19
in the associated continuum. Known variability argues for the presence of
microlensing. We show that microlensing can account for both the continuum and
emission line flux ratios, if the broad emission line region is comparable in
size to the Einstein radii of the microlenses. Specifically, we need the
half-light radius of the broad-line region to be R_BLR <~ 0.4 Rein ~ 9$
lt-days, which is small but reasonable. If the broad-line region is that large,
then stars can contribute only 15-20% of the surface mass density at the
positions of the images. While we cannot exclude the possibility that
millilensing by dark matter substructure is present as well, we conclude that
microlensing is present and sufficient to explain existing data. Under this
hypothesis, the A/D flux ratio should return to a value close to unity on a
time scale of years rather than millennia.


title: Microlensing of Central Images in Strong Gravitational Lens Systems

abstract:
  We study microlensing of the faint images that form close to the centers of
strong gravitational lens galaxies. These central images, which have finally
begun to yield to observations, naturally appear in dense stellar fields and
may be particularly sensitive to fine granularity in the mass distribution. The
microlensing magnification maps for overfocussed (i.e., demagnified) images
differ strikingly from those for magnified images. In particular, the familiar
"fold" and "cusp" features of maps for magnified images are only present for
certain values of the fraction, f, of the surface mass density contained in
stars. For central images, the dispersion in microlensing magnifications is
generally larger than for normal (minimum and saddle) images, especially when
the source is comparable to or larger than the stellar Einstein radius. The
dispersion depends in a complicated way on f; this behaviour may hold the key
to using microlensing as a probe of the relative densities of stars and dark
matter in the cores of distant galaxies. Quantitatively, we predict that the
central image C in PMN J1632-0033 has a magnification dispersion of 0.6
magnitudes for Rsrc/Rein <~ 1, or 0.3 mag for Rsrc/Rein = 10. For comparison,
the dispersions are 0.5-0.6 mag for image B and 0.05-0.1 mag for image A, if
Rsrc/Rein <~ 1; and just 0.1 mag for B and 0.008 mag for A if Rsrc/Rein = 10.
(The dispersions can be extrapolated to larger sources sizes as sigma \propto
Rsrc^{-1}.) Thus, central images are more susceptible than other lensed images
to microlensing and hence good probes for measuring source sizes.


title: The Age and Progenitor Mass of Sirius B

abstract:
  The Sirius AB binary system has masses that are well determined from many
decades of astrometric measurements. Because of the well-measured radius and
luminosity of Sirius A, we employed the TYCHO stellar evolution code to
determine the age of the Sirius A,B binary system accurately, at 225-250 Myr.
Note that this fit requires the assumption of solar abundance, and the use of
the new Asplund et al. primordial solar metallicity. No fit to Sirius A's
position is possible using the old Grevesse & Sauval scale. Because the Sirius
B white dwarf parameters have also been determined accurately from space
observations, the cooling age could be determined from recent calculations by
Fontaine et al. or Wood to be 124 +/- 10 Myr. The difference of the two ages
yields the nuclear lifetime and mass of the original primary star, 5.056
+0.374/-0.276 solar masses. This result yields in principle the most accurate
data point at relatively high masses for the initial-final mass relation.
However, the analysis relies on the assumption that the primordial abundance of
the Sirius stars was solar, based on membership in the Sirius supercluster. A
recent study suggests that its membership in the group is by no means certain.


title: Characteristic Scales During Reionization

abstract:
  One of the key observables of the reionization era is the distribution of
neutral and ionized gas. Recently, Furlanetto, Zaldarriaga, & Hernquist
developed a simple analytic model to describe the growth of HII regions during
this era. Here, we examine some of the fundamental simplifying assumptions
behind this model and generalise it in several important ways. The model
predicts that the ionized regions attain a well-defined characteristic size R_c
that ranges from R_c~1 Mpc in the early phases to R_c>10 Mpc in the late
phases. We show that R_c is determined primarily by the bias of the galaxies
driving reionization; hence measurements of this scale constrain a fundamental
property of the first galaxies. The variance around R_c, on the other hand, is
determined primarily by the underlying matter power spectrum. We then show that
increasing the ionizing efficiency of massive galaxies shifts R_c to
significantly larger scales and decreases the importance of recombinations.
These differences can be observed with forthcoming redshifted 21 cm surveys
(increasing the brightness temperature fluctuations by up to a factor of two on
large scales) and with measurements of small-scale anisotropies in the cosmic
microwave background. Finally, we show that stochastic fluctuations in the
galaxy population only broaden the bubble size distribution significantly if
massive galaxies are responsible for most of the ionizing photons. We argue
that the key results of this model are robust to many of our uncertainties
about the reionization process.


title:
Secular Evolution in Disk Galaxies: The Growth of Pseudobulges and
  Problems for Cold Dark Matter Galaxy Formation

abstract:
  We review internal secular evolution in galaxy disks -- the fundamental
process by which isolated disks evolve. We concentrate on the buildup of dense
central features that look like classical, merger-built bulges but that were
made slowly out of disk gas. We call these pseudobulges. As an existence proof,
we review how bars rearrange disk gas into outer rings, inner rings, and gas
dumped into the center. In simulations, this gas reaches high densities, and in
the observations, many SB and oval galaxies show central concentrations of gas.
Associated star formation rates imply plausible pseudobulge growth times of a
few billion years. If secular processes built dense centers that masquerade as
bulges, can we distinguish them from merger-built bulges? Observations show
that pseudobulges retain a memory of their disky origin. They have one or more
characteristics of disks: (1) flatter shapes than those of classical bulges,
(2) larger ratios of ordered to random velocities, (3) smaller velocity
dispersions, (4) nuclear bars or spiral structure, (5) boxy structure when seen
edge-on, (6) nearly exponential brightness profiles, and (7) starbursts. These
features occur preferentially in barred and oval galaxies in which secular
evolution should be rapid. So the cleanest examples of pseudobulges are
recognizable. Thus observations and theory contribute to a new picture of
galaxy evolution that complements hierarchical clustering and merging. However,
an important problem with cold dark matter galaxy formation gets more acute.
How can hierarchical clustering produce so many pure disk galaxies with no
evidence for merger-built bulges?


title: Proper Motions of the HH 47 Jet Observed with the Hubble Space Telescope

abstract:
  We present a proper motion study of the shock waves within the classic
stellar jet HH 47 based on Hubble Space Telescope H-alpha and [S II] images of
the region taken over two epochs. Individual knots within the jet and in the
bow shock/Mach disk working surface of HH 47A move significantly in the five
years that separate the images, and the excellent spatial resolution of HST
makes it possible to measure the proper motions with enough precision to easily
observe differential motions throughout the flow. The bright portion of the jet
emerges at 37.5 +/- 2.5 degrees from the plane of the sky with an average
velocity of 300 km/s. Dynamical ages of the shock waves in the jet range from a
few decades for knots recently ejected by the source to ~ 1300 years for the
faint extended bow shock HH 47D. The jet curves, but motions of knots in the
jet are directed radially away from the exciting source, and velocity
variability in the flow drives the shock waves that heat the jet internally.
The jet orientation angle varies with time by about 15 degrees, and currently
points to the northwestern portion of a cavity outlined by a reflection nebula,
where a quasi-stationary shock deflects the jet. The major working surface HH
47A is more complex than a simple bow shock/Mach disk, and contains numerous
clumps that move relative to one another with velocities of ~ +/- 40 km/s.
Small clumps or instabilities affect the Mach disk, and dense clumps may move
all the way through the working surface to cause the bumpy morphology seen at
the bow shock. A localized area between the bow shock and Mach disk varies
significantly between the two sets of images.


title:
An Active Instance-based Machine Learning method for Stellar Population
  Studies

abstract:
  We have developed a method for fast and accurate stellar population
parameters determination in order to apply it to high resolution galaxy
spectra. The method is based on an optimization technique that combines active
learning with an instance-based machine learning algorithm. We tested the
method with the retrieval of the star-formation history and dust content in
"synthetic" galaxies with a wide range of S/N ratios. The "synthetic" galaxies
where constructed using two different grids of high resolution theoretical
population synthesis models. The results of our controlled experiment shows
that our method can estimate with good speed and accuracy the parameters of the
stellar populations that make up the galaxy even for very low S/N input. For a
spectrum with S/N=5 the typical average deviation between the input and fitted
spectrum is less than 10**{-5}. Additional improvements are achieved using
prior knowledge.


title: Electron Surfing Acceleration in Magnetic Reconnection

abstract:
  We discuss that energetic electrons are generated near the X-type magnetic
reconnection region due to a surfing acceleration mechanism. In a thin plasma
sheet, the polarization electric fields pointing towards the neutral sheet are
induced around the boundary between the lobe and plasma sheet in association
with the Hall electric current. By using a particle-in-cell simulation, we
demonstrate that the polarization electric fields are strongly enhanced in an
externally driven reconnection system, and some electrons can be trapped by the
electrostatic potential well of the polarization field. During the trapping
phase, the electrons can gain their energies from the convection/inductive
reconnection electric fields. We discuss that relativistic electrons with MeV
energies are quickly generated in and around the X-type neutral region by
utilizing the surfing acceleration.


title: Quark stars within relativistic models

abstract:
  Lately, it has been suggested that strange (quark) stars can be responsible
for glitches and other observational features of pulsars. Some discussions on
whether quark stars, if really exist, are bare or crusted are also a source of
controversy in the recent literature. In the present work we use the
Nambu-Jona-Lasinio model, known to incorporate chiral symmetry, necessarily
present in the QCD formalism, in order to describe quark star properties. We
compare our results for the stars and the features of the model with the much
simpler model normally used in the description of strange stars, namely the MIT
bag model. We also investigate the differences in the stellar properties which
arise due to the presence of the crust. We show that the NJL model produces
results which are somewhat different as compared with the MIT model.


title:
Faint Blue Objects in the Hubble Deep Field South Revealed: White
  Dwarfs, Subdwarfs, and Quasars

abstract:
  We explore the nature of the faint blue objects in the Hubble Deep Field
South. We have derived proper motions for the point sources in the Hubble Deep
Field South using a 3 year baseline. Combining our proper motion measurements
with spectral energy distribution fitting enabled us to identify 4 quasars and
42 stars, including 3 white dwarf candidates. Two of these white dwarf
candidates, HDFS 1444 and 895, are found to display significant proper motion,
21.1 $\pm$ 7.9 mas/yr and 34.9 $\pm$ 8.0 mas/yr, and are consistent with being
thick disk or halo white dwarfs located at ~2 kpc. The other faint blue objects
analyzed by Mendez & Minniti do not show any significant proper motion and are
inconsistent with being halo white dwarfs; they do not contribute to the
Galactic dark matter. The observed population of stars and white dwarfs is
consistent with standard Galactic models.


title:
Depolarization of radio bursts due to reflection off sharp boundaries in
  the solar corona

abstract:
  It is argued that depolarization of solar radio bursts requires reflection
off boundary layers no thicker than about a wavelength (a few meters at most)
between regions with large density ratios. The implied inhomogeneities suggest
that the corona is much more highly and sharply structured than can be resolved
from observations at other wavelengths. A simplified version of magnetoionic
theory is used to derive a depolarization coefficient: the effect of the
magnetic field is ignored in treating the dispersion, but taken into account in
treating the (circular) polarization. Plots of the depolarization coefficient
are used to infer conditions under which effective depolarization occurs, and
it is concluded that favorable conditions require total internal reflection.
For type I sources away from the central meridian, effective depolarization
requires reflection off an overdense structure with a density ratio
$\xi\approx10$. For type III bursts, a density ratio $\xi\approx2$ suffices,
with at least two reflections off walls of ducts at $\approx20^\circ$ to the
radial.


title: Cool Dark Cosmic Dust as a Reservoir of Absorbed Energy

abstract:
  The conception of cool dark cosmic dust has been proposed. The process of
accumulation of absorbed energy by dust of such kind is considered. The
conception of accumulation horizon is introduced. The possible role of cool
dark cosmic dust is discussed for solution of the problem of dark matter. The
other aspects of the problem are also considered.


title: Stellar disk truncations at high-z: probing inside-out galaxy formation

abstract:
  We have conducted a systematic search for stellar disk truncations in
disk-like galaxies at intermediate redshift (z<1.1) using the Hubble Ultra Deep
Field (UDF) data. We use the position of the truncation as a direct estimator
of the size of the stellar disk. After accounting for the surface brightness
evolution of the galaxies, our results suggest that the radial position of the
truncations has increased with cosmic time by ~1-3 kpc in the last ~8 Gyr. This
result indicates a small to moderate (~25%) inside-out growth of the disk
galaxies since z~1.


title: The XMM-Newton/2dF survey-VIII: The extended X-ray sources

abstract:
  We present a sample of eight extended X-ray sources detected in the
wide-field (~2.3 deg^2), bright (2-10 ksec) XMM-Newton/2dF survey, reaching a
flux limit of ~2 X 10^{-14} erg/s/cm^2. Of these, seven are identified as
secure X-ray clusters in the soft 0.3-2 keV band using a standard wavelet
algorithm on either the PN or the MOS images. Spectroscopic or photometric
redshifts are available for five clusters, spanning a range between 0.12 and
0.68. The X-ray spectral fittings show temperatures between 1 and 4.6 keV,
characteristic of poor clusters and groups of galaxies. We derive for the first
time the XMM-Newton cluster number count log N-log S distribution albeit with
poor statistics. Both the log N-\log S and the Luminosity-Temperature relation
are in good agreement with previous ROSAT results.


title:
New Light on the Initial Mass Function of the Galactic Halo Globular
  Clusters

abstract:
  We present new constraints on the initial mass spectrum of the Galactic Old
Halo globular clusters. This has remained poorly-known so far, as both an
initial power-law mass spectrum and an initial lognormal mass function could
have evolved into the presently observed globular cluster mass distribution,
making the initial contribution of now lost low-mass objects ill-determined.
Our approach consists in comparing the evolution with time of both the radial
mass density profile and the number density profile of the globular cluster
system. Using the analytical expression established by Vesperini & Heggie for
the temporal evolution of the mass of a globular cluster on a circular orbit in
a stable Galactic potential, we evolve the mass and number density profiles of
many putative globular cluster systems, each starting with different initial
cluster mass spectrum and initial cluster space-density. We then compare the
modelled profiles with those of the Old Halo cluster system in order to
investigate which system(s) provide(s) the best consistency with the data.
(abridged)


title: Photometry from online Digitized Sky Survey Plates

abstract:
  Online Digital Sky Survey (DSS) material is often used to obtain information
on newly discovered variable stars for older epochs (e.g. Nova progenitors,
flare stars, ...). We present here the results of an investigation of
photometry on online digital sky survey material in small fields calibrated by
CCD sequences. We compared different source extraction mechanisms and found,
that even down near to the sensitivity limit, despite the H-compression used
for the online material, photometry with an accuracy better than 0\fm1 rms is
possible on DSS-II. Our investigation shows that the accuracy depends strongly
on the source extraction method. The SuperCOSMOS scans, although retrieved with
an higher spatial resolution, do not give us better results. The methods and
parameters presented here, allow the user to obtain good plate photometry in
small fields down to the Schmidt plate survey limits with a few bright CCD
calibrators, which may be calibrated with amateur size telescopes. Especially
for the events mentioned above, new field photometry for calibration purposes
mostly exists, but the progenitors were not measured photometrically before.
Also the follow up whether stellar concentrations are newly detected clusters
or similar work may be done without using mid size telescopes. The calibration
presented here is a "local" one for small fields. We show that this method
presented here gives higher accuracies than "global" calibrations of surveys
(e.g. GSC-II, SuperCOSMOS and USNO-B)


title:
Time scales of Li evolution: a homogeneous analysis of open clusters
  from ZAMS to late-MS

abstract:
  We have performed a new and homogeneous analysis of all the Li data available
in the literature for main sequence stars (spectral-types from late F to K) in
open clusters. In the present paper we focus on a detailed investigation of MS
Li depletion and its time scales for stars in the 6350-5500 K effective
temperature range. For the first time, we were able to constrain the age at
which non-standard mixing processes, driving MS Li depletion, appear. We have
also shown that MS Li depletion is not a continuous process and cannot be
simply described by a t^(-alpha) law. We confirm that depletion becomes
ineffective beyond an age of 1-2 Gyr for the majority of the stars, leading to
a Li plateau at old ages. We compared the empirical scenario of Li as a
function of age with the predictions of three non-standard models. We found
that models including only gravity waves as main mixing process are not able to
fit the Li vs. age pattern and thus this kind of mixing can be excluded as the
predominant mechanism responsible for Li depletion. On the other hand, models
including slow mixing induced by rotation and angular momentum loss, and in
particular those including also diffusive processes not related to rotation,
can explain to some extent the empirical evidence. However, none of the
currently proposed models can fit the plateau at old ages.


title:
A procedure to produce excess, probability and significance maps and to
  compute point-sources flux upper limits

abstract:
  A short note to propose a procedure to construct excess maps, probability
maps and to calculate point source flux upper limits.


title: Low Order Aberrations in Band-Limited Lyot Coronagraphs

abstract:
  We study the way Lyot coronagraphs with unapodized entrance pupils respond to
small, low order phase aberrations. This study is applicable to ground-based
adaptive optics coronagraphs operating at 90% and higher Strehl ratios, as well
as to some space-based coronagraphs with intrinsically higher Strehl ratio
imaging. We utilize a second order expansion of the monochromatic point-spread
function (written as a power spectrum of a power series in the phase aberration
over clear aperture) to derive analytical expressions for the response of a
`band-limited' Lyot coronagraph (BLC) to small, low order, phase aberrations.
The BLC possesses a focal plane mask with an occulting spot whose opacity
profile is a spatially band-limited function rather than a hard-edged, opaque
disk. The BLC is, to first order, insensitive to tilt and astigmatism.
Undersizing the stop in the re-imaged pupil plane (the Lyot plane) following
the focal plane mask can alleviate second order effects of astigmatism, at the
expense of system throughput and angular resolution. The optimal degree of such
undersizing depends on individual instrument designs and goals. Our analytical
work engenders physical insight, and complements existing numerical work on
this subject. Our methods can be extended to treat the passage of higher order
aberrations through band-limited Lyot coronagraphs, by using our polynomial
decomposition or an analogous Fourier approach.


title:
Stochastical distributions of lens and source properties for observed
  galactic microlensing events

abstract:
  A comprehensive new approach is presented for deriving probability densities
of physical properties characterizing lens or source that constitute an
observed galactic microlensing event. While previously encountered problems are
overcome, constraints from event anomalies and model parameter uncertainties
can be incorporated into the estimate. Probability densities for given events
need to be carefully distinguished from the statistical distribution of the
same parameters among the underlying population from which the actual lenses
and sources are drawn. Using given model distributions of the mass spectrum,
the mass density, and the velocity distribution of Galactic disk and bulge
constituents, probability densities of lens mass, distance, and the effective
lens-source velocities are derived, where the effect on the distribution that
arises from additional observations of annual parallax or finite-source
effects, or the absence of significant effects, is shown. The presented
formalism can also be used to calculate probabilities for the lens to belong to
one or another population and to estimate parameters that characterize
anomalies. Finally, it is shown how detection efficiency maps for binary-lens
companions in the physical parameters companion mass and orbital semi-major
axis arise from values determined for the mass ratio and dimensionless
projected separation parameter, including the deprojection of the orbital
motion for elliptical orbits. Compared to the naive estimate based on 'typical
values', the detection efficiency for low-mass companions is increased by
mixing in higher detection efficiencies for smaller mass ratios (i.e. smaller
masses of the primary).


title: Neural network correction of astrometric chromaticity

abstract:
  In this paper we deal with the problem of chromaticity, i.e. apparent
position variation of stellar images with their spectral distribution, using
neural networks to analyse and process astronomical images. The goal is to
remove this relevant source of systematic error in the data reduction of high
precision astrometric experiments, like Gaia. This task can be accomplished
thanks to the capability of neural networks to solve a nonlinear approximation
problem, i.e. to construct an hypersurface that approximates a given set of
scattered data couples. Images are encoded associating each of them with
conveniently chosen moments, evaluated along the y axis. The technique
proposed, in the current framework, reduces the initial chromaticity of few
milliarcseconds to values of few microarcseconds.


title: The build-up of the Coma cluster by infalling substructures

abstract:
  We present a new multiwavelength analysis of the Coma cluster subclustering
based on recent X-ray data and on a compilation of nearly 900 redshifts. We
characterize subclustering using the Serna&Gerbal (1996) hierarchical method
which makes use of galaxy positions, redshifts, and magnitudes, and identify 17
groups. One of these groups corresponds to the main cluster, one is the well
known group associated with the infalling galaxy NGC4839 and one is associated
with NGC4911/NGC4926. About one third of the 17 groups have velocity
distributions centered on the velocities of the very bright cluster galaxies
they contain (magnitudes R<13). In order to search for additional
substructures, we make use of the isophotes of X-ray brightness residuals left
after the subtraction of the best-fit beta-model from the overall X-ray gas
distribution (Neumann et al. 2003). We select galaxies within each of these
isophotes and compare their velocity distributions with that of the whole
cluster. We confirm in this way the two groups associated, respectively, with
NGC4839, and with the southern part of the extended western substructure
visible in X-rays. We discuss the group properties in the context of a scenario
in which Coma is built by the accretion of groups infalling from the
surrounding large scale structure. We estimate the recent mass accretion rate
of Coma and compare it with hierarchical models of cluster evolution.


title:
Comparison between methods for the determination of the primary cosmic
  ray mass composition from the longitudinal profile of atmospheric cascades

abstract:
  The determination of the primary cosmic ray mass composition from the
longitudinal development of atmospheric cascades is still a debated issue. In
this work we discuss several data analysis methods and show that if the entire
information contained in the longitudinal profile is exploited, reliable
results may be obtained. Among the proposed methods FCC ('Fit of the Cascade
Curve'), MTA ('Multiparametric Topological Analysis') and NNA ('Neural Net
Analysis') with conjugate gradient optimization algorithm give the best
accuracy.