title: Merger driven ULIRG-QSO evolution: The case of 3C 48

abstract:
  The QSO 3C 48 and its host galaxy constitute a nearby template object of the
proposed merger-driven evolutionary sequence from ULIRGs to QSOs. In this
contribution multi-wavelength observations and N-body simulations studying the
structural and compositional properties of this late-stage major merger will be
presented. Key questions addressed will be the nature of the apparent second
nucleus 3C 48A and absence of a counter tidal tail. The results will be used to
review the role of 3C 48 in the ULIRG-QSO evolutionary scenario.


title:
New insights into ultraluminous X-ray sources from deep XMM-Newton
  observations

abstract:
  The controversy over whether ultraluminous X-ray sources (ULXs) contain a new
intermediate-mass class of black holes (IMBHs) remains unresolved. We present
new analyses of the deepest XMM-Newton observations of ULXs that address their
underlying nature. We examine both empirical and physical modelling of the
X-ray spectra of a sample of thirteen of the highest quality ULX datasets, and
find that there are anomalies in modelling ULXs as accreting IMBHs with
properties simply scaled-up from Galactic black holes. Most notably, spectral
curvature above 2 keV in several sources implies the presence of an
optically-thick, cool corona. We also present a new analysis of a 100 ks
observation of Holmberg II X-1, in which a rigorous analysis of the temporal
data limits the mass of its black hole to no more than 100 solar masses. We
argue that a combination of these results points towards many (though not
necessarily all) ULXs containing black holes that are at most a few 10s of
solar mass in size.


title:
XMM-Newton and Deep Optical Observations of the OTELO fields: the
  Groth-Westphal Strip

abstract:
  OTELO (OSIRIS Tunable Emission Line Object Survey) will be carried out with
the OSIRIS instrument at the 10 m GTC telescope at La Palma, and is aimed to be
the deepest and richest survey of emission line objects to date. The deep
narrow-band optical data from OSIRIS will be complemented by means of
additional observations that include: (i) an exploratory broad-band survey that
is already being carried out in the optical domain, (ii) FIR and sub-mm
observations to be carried with the Herschel space telescope and the GTM, and
(iii) deep X-Ray observations from XMM-Newton and Chandra.Here we present a
preliminary analysis of public EPIC data of one of the OTELO targets,the
Groth-Westphal strip, gathered from the XMM-Newton Science Archive (XSA). EPIC
images are combined with optical BVRI data from our broadband survey carried
out with the 4.2m WHT at La Palma. Distance-independent diagnostics (involving
X/O ratio, hardness ratios, B/T ratio) are tested.


title: A Catalog of MSX Infrared Dark Cloud Candidates

abstract:
  We use 8.3 um mid-infrared images acquired with the Midcourse Space
Experiment satellite to identify and catalog Infrared Dark Clouds (IRDCs) in
the first and fourth quadrants of the Galactic plane. Because IRDCs are seen as
dark extinction features against the diffuse Galactic infrared background, we
identify them by first determining a model background from the 8.3 um images
and then searching for regions of high decremental contrast with respect to
this background. IRDC candidates in our catalog are defined by contiguous
regions bounded by closed contours of a 2 sigma decremental contrast threshold.
Although most of the identified IRDCs are actual cold, dark clouds, some as yet
unknown fraction may be spurious identifications. For large, high contrast
clouds, we estimate the reliability to be 82%. Low contrast clouds should have
lower reliabilities. Verification of the reality of individual clouds will
require additional data. We identify 10,931 candidate infrared dark clouds. For
each IRDC, we also catalog cores. These cores, defined as localized regions
with at least 40% higher extinction than the cloud's average extinction, are
found by iteratively fitting 2-dimensional elliptical Gaussians to the contrast
peaks. We identify 12,774 cores. The catalog contains the position, angular
size, orientation, area, peak contrast, peak contrast signal-to-noise, and
integrated contrast of the candidate IRDCs and their cores. The distribution of
IRDCs closely follows the Galactic diffuse mid-infrared background and peaks
toward prominent star forming regions, spiral arm tangents, and the so-called 5
kpc Galactic molecular ring.


title: Effects of Rotation on Mass Loss for Population III stars

abstract:
  The effects of rotation on low-metallicity stellar models are twofold: first,
the models reach break-up during main sequence and may lose mass by mechanical
process; second, strong internal mixing brings freshly synthesized elements
towards the surface and raises the effective metallicity to higher values, so
that the initially very low radiative winds are enhanced. Those two effects are
also found in Z=0 models, but to a lesser degree because of structural
differences. This weak mass loss becomes interesting though in the case of the
black hole-doomed stars (25-140 M_\sun and > 260 M_\sun) because it allows
these stars to contribute to the enrichment of the medium by stellar winds.


title: The Nature of the Peculiar Virgo Cluster Galaxies NGC 4064 and NGC 4424

abstract:
  We present a detailed study of the peculiar HI-deficient Virgo cluster spiral
galaxies NGC 4064 and NGC 4424, using $^{12}$CO 1-0 interferometry, optical
imaging and integral-field spectroscopic observations, in order to learn what
type of environmental interactions have afected these galaxies. Optical imaging
reveals that NGC 4424 has a strongly disturbed stellar disk, with banana-shaped
isophotes and shells. NGC 4064, which lies in the cluster outskirts, possesses
a relatively undisturbed outer stellar disk and a central bar. In both galaxies
H-alpha emission is confined to the central kiloparsec. CO observations reveal
bilobal molecular gas morphologies, with H-alpha emission peaking inside the CO
lobes, implying a time sequence in the star formation process.Gas kinematics
reveals strong bar-like non-circular motions in the molecular gas in both
galaxies, suggesting that the material is radially infalling. In NGC 4064 the
stellar kinematics reveal strong bar-like non-circular motions in the central 1
kpc. On the other hand, NGC 4424 has extremely modest stellar rotation
velocities (Vmax ~ 30 km s-1), and stars are supported by random motions as far
out as we can measure it. The observations suggest that the peculiarities of
NGC 4424 are the result of an intermediate-mass merger plus ram pressure
stripping. In the case of NGC 4064, the evidence suggests an already stripped
"truncated/normal" galaxy that recently suffered a minor merger or tidal
interaction with another galaxy. We propose that galaxies with
"truncated/compact" H-alpha morphologies such as these are the result of the
independent effects of ram pressure stripping, which removes gas from the outer
disk, and gravitational interactions such as mergers, which heat stellar disks,
drive gas to the central kpc and increase the central mass concentrations.


title: On the width and shape of gaps in protoplanetary disks

abstract:
  Although it is well known that a massive planet opens a gap in a
proto-planetary gaseous disk, there is no analytic description of the surface
density profile in and near the gap. The simplest approach, which is based upon
the balance between the torques due to the viscosity and the gravity of the
planet and assumes local damping, leads to gaps with overestimated width,
especially at low viscosity. Here, we take into account the fraction of the
gravity torque that is evacuated by pressure supported waves. With a novel
approach, which consists of following the fluid elements along their
trajectories, we show that the flux of angular momentum carried by the waves
corresponds to a pressure torque. The equilibrium profile of the disk is then
set by the balance between gravity, viscous and pressure torques. We check that
this balance is satisfied in numerical simulations, with a planet on a fixed
circular orbit. We then use a reference numerical simulation to get an ansatz
for the pressure torque, that yields gap profiles for any value of the disk
viscosity, pressure scale height and planet to primary mass ratio. Those are in
good agreement with profiles obtained in numerical simulations over a wide
range of parameters. Finally, we provide a gap opening criterion that
simultaneously involves the planet mass, the disk viscosity and the aspect
ratio.


title:
Observational Constraints on Dust Disk Lifetimes: Implications for
  Planet Formation

abstract:
  (abridged) Thus far our impressions regarding the evolutionary time scales
for young circumstellar disks have been based on small number statistics. Over
the past decade, however, in addition to precision study of individual
star/disk systems, substantial observational effort has been invested in
obtaining less detailed data on large numbers of objects in young star
clusters. This has resulted in a plethora of information now enabling
statistical studies of disk evolutionary diagnostics. Along an ordinate one can
measure disk presence or strength through indicators such as ultraviolet/blue
excess or spectroscopic emission lines tracing accretion, infrared excess
tracing dust, or millimeter flux measuring mass. Along an abscissa one can
track stellar age.
  While bulk trends in disk indicators versus age are evident, observational
errors affecting both axes, combined with systematic errors in our
understanding of stellar ages, both cloud and bias any such trends Thus
detailed understanding of the physical processes involved in disk dissipation
and of the relevant time scales remains elusive. Nevertheless, a clear effect
in current data that is unlikely to be altered by data analysis improvements is
the dispersion in disk lifetimes. The age at which evidence for inner accretion
disks ceases to be apparent for the vast majority (90%) of stars is in the
range 3-8 Myr. More distant, terrestrial zone dust is traced by mid-infrared
emission where sufficient sensitivity and uniform data collection are only now
being realized with data return from the Spitzer Space Telescope.


title:
A Coherent Timing Solution for the Nearby Isolated Neutron Star RX
  J1308.6+2127/RBS 1223

abstract:
  We present a phase-connected timing solution for the nearby isolated neutron
star RX J1308.6+2127 (RBS 1223). From dedicated Chandra observations as well as
archival Chandra and XMM-Newton data spanning a period of five years, we
demonstrate that the 10.31-sec pulsations are slowing down steadily at a rate
of Pdot=1.120(3)e-13 s/s. Under the assumption that this is due to magnetic
dipole torques, we infer a characteristic age of 1.5 Myr and a magnetic field
strength of 3.4e13 G. As with RX J0720.4-3125, the only other radio-quiet
thermally emitting isolated neutron star for which a timing solution has been
derived, the field strength is consistent with what was inferred earlier from
the presence of a strong absorption feature in its X-ray spectrum. Furthermore,
both sources share that the characteristic age is in excess of the cooling age
inferred from standard cooling models. The sources differ, however, in their
timing noise: while RX J0720.4-3125 showed considerable timing noise, RX
J1308.6+2127 appears relatively stable.


title: CSL-1: Lensing by a Cosmic String or a Dark Matter Filament?

abstract:
  The lens candidate CSL-1 has been interpreted as evidence for a cosmic
string. Here we test the hypothesis that the lensing comes from a tidally
disrupted dark matter halo. We calculate the mass-density relationship that one
would expect from structure formation theory and come to the conclusion that in
order to explain the lensing using dark matter, the halo would have to have a
mass greater than the Milky Way. There is apparently no such object seen in the
data. If the follow up observations confirm that the two objects are indeed
images of the same galaxy, then it seems difficult to explain the lens using
dark matter.


title: Learning from the Scatter in Type Ia Supernovae

abstract:
  Type Ia Supernovae are standard candles so their mean apparent magnitude has
been exploited to learn about the redshift-distance relationship. Besides
intrinsic scatter in this standard candle, additional source of scatter is
caused by gravitational magnification by large scale structure. Here we probe
the dependence of this dispersion on cosmological parameters and show that
information about the amplitude of clustering, \sigma_8, is contained in the
scatter. In principle, it will be possible to constrain \sigma_8 to within 5%
with observations of 2000 Type Ia Supernovae. However, extracting this
information requires subtlety as the distribution of magnifications is far from
Gaussian. If one incorrectly assumes a Gaussian distribution, the estimate of
the clustering amplitude will be biased three-\sigma away from the true value.


title:
Complexity on Small Scales: The Metallicity Distribution of the Carina
  Dwarf Spheroidal Galaxy

abstract:
  The Carina dwarf spheroidal (dSph) galaxy is the only galaxy of this type
that shows clearly episodic star formation separated by long pauses. Here we
present metallicities for 437 radial velocity members of this Galactic
satellite. We obtained medium-resolution spectroscopy with the multi-object
spectrograph FLAMES at the ESO VLT. Our target red giants cover the entire
projected surface area of Carina. Our spectra are centered at the near-infrared
Ca triplet, which is a well-established metallicity indicator for old and
intermediate-age red giants. The resulting data sample provides the largest
collection of spectroscopically derived metallicities for a Local Group dSph to
date. Four of our likely radial velocity members of Carina lie outside of this
galaxy's nominal tidal radius, supporting earlier claims of the possible
existence of such stars beyond the main body of Carina. We find a mean
metallicity of [Fe/H]=-1.7 dex. The formal full width at half maximum of the
metallicity distribution is 0.92 dex, while the full range of metallicities
spans ~-3.0<[Fe/H]<0.0 dex. The metallicity distribution might be indicative of
several subpopulations. There appears to be a mild radial gradient such that
more metal-rich populations are more centrally concentrated, matching a similar
trend for an increasing fraction of intermediate-age stars. This as well as the
photometric colors of the more metal-rich red giants suggest that Carina
exhibits an age-metallicity relation. Indeed the age-metallicity degeneracy
seems to conspire to form a narrow red giant branch despite the considerable
spread in metallicity and wide range of ages. The metallicity distribution is
not well-matched by a simple closed-box model of chemical evolution, but
requires models that take into account also infall and outflows. (Abridged)


title:
Supergiant Fast X-ray Transients: A new class of high mass X-ray
  binaries unveiled by INTEGRAL

abstract:
  INTEGRAL monitoring of the Galactic Plane is revealing a growing number of
recurrent X-ray transients, characterised by short outbursts with very fast
rise times (~ tens of minutes) and typical durations of a few hours. Here we
show that several of these transients are associated with OB supergiants and
hence define a new class of massive X-ray binaries which we call Supergiant
Fast X-ray Transients (SFXTs). Many other transient X-ray sources display
similar X-ray characteristics, suggesting that they belong to the same class.
Since they are difficult to detect and their number is growing fast and
steadily, they could represent a major class of X-ray binaries.


title:
First cosmic shear results from the Canada-France-Hawaii Telescope Wide
  Synoptic Legacy Survey

abstract:
  We present the first measurements of the weak gravitational lensing signal
induced by the large scale mass distribution from data obtained as part of the
ongoing Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). The data used in
this analysis are from the Wide Synoptic Survey, which aims to image ~170
square degree in five filters. We have analysed ~22 deg2 (31 pointings) of i'
data spread over two of the three survey fields. These data are of excellent
quality and the results bode well for the remainder of the survey: we do not
detect a significant `B'-mode, suggesting that residual systematics are
negligible at the current level of accuracy. Assuming a Cold Dark Matter model
and marginalising over the Hubble parameter h=[0.6,0.8], the source redshift
distribution and systematics, we constrain sigma_8, the amplitude of the matter
power spectrum. At a fiducial matter density Omega_m=0.3 we find
sigma_8=0.85+-0.06. This estimate is in excellent agreement with previous
studies. Combination of our results with those from the Deep component of the
CFHTLS enables us to place a constraint on a constant equation of state for the
dark energy, based on cosmic shear data alone. We find that w_0<-0.8 at 68%
confidence.


title: Cosmic Shear Analysis with CFHTLS Deep data

abstract:
  We present the first cosmic shear measurements obtained from the T0001
release of the Canada-France-Hawaii Telescope Legacy Survey. The data set
covers three uncorrelated patches (D1, D3 and D4) of one square degree each
observed in u*, g', r', i' and z' bands, out to i'=25.5. The depth and the
multicolored observations done in deep fields enable several data quality
controls. The lensing signal is detected in both r' and i' bands and shows
similar amplitude and slope in both filters. B-modes are found to be
statistically zero at all scales. Using multi-color information, we derived a
photometric redshift for each galaxy and separate the sample into medium and
high-z galaxies. A stronger shear signal is detected from the high-z subsample
than from the low-z subsample, as expected from weak lensing tomography. While
further work is needed to model the effects of errors in the photometric
redshifts, this results suggests that it will be possible to obtain constraints
on the growth of dark matter fluctuations with lensing wide field surveys. The
various quality tests and analysis discussed in this work demonstrate that
MegaPrime/Megacam instrument produces excellent quality data. The combined Deep
and Wide surveys give sigma_8= 0.89 pm 0.06 assuming the Peacock & Dodds
non-linear scheme and sigma_8=0.86 pm 0.05 for the halo fitting model and
Omega_m=0.3. We assumed a Cold Dark Matter model with flat geometry.
Systematics, Hubble constant and redshift uncertainties have been marginalized
over. Using only data from the Deep survey, the 1 sigma upper bound for w_0,
the constant equation of state parameter is w_0 < -0.8.


title:
Properties of the energetic particle distributions during the October
  28, 2003 solar flare from INTEGRAL/SPI observations

abstract:
  Analysis of spectra obtained with the gamma-ray spectrometer SPI onboard
INTEGRAL of the GOES X17-class flare on October 28, 2003 is presented. In the
energy range 600 keV - 8 MeV three prominent narrow lines at 2.223, 4.4 and 6.1
MeV, resulting from nuclear interactions of accelerated ions within the solar
atmosphere could be observed. Time profiles of the three lines and the
underlying continuum indicate distinct phases with several emission peaks and
varying continuum-to-line ratio for several minutes before a smoother decay
phase sets in. Due to the high-resolution Ge detectors of SPI and the
exceptional intensity of the flare, detailed studies of the 4.4 and 6.1 MeV
line shapes was possible for the first time. Comparison with calculated line
shapes using a thick target interaction model and several energetic particle
angular distributions indicates that the nuclear interactions were induced by
downward-directed particle beams with alpha-to-proton ratios of the order of
0.1. There are also indications that the 4.4 MeV to 6.1 MeV line fluence ratio
changed between the beginning and the decay phase of the flare, possibly due to
a temporal evolution of the energetic particle alpha-to-proton ratio.


title:
C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate
  emission and grain growth

abstract:
  Infrared ~5--35 um spectra for 40 solar-mass T Tauri stars and 7
intermediate-mass Herbig Ae stars with circumstellar disks were obtained using
the Spitzer Space Telescope as part of the c2d IRS survey. This work
complements prior spectroscopic studies of silicate infrared emission from
disks, which were focused on intermediate-mass stars, with observations of
solar-mass stars limited primarily to the 10 um region. The observed 10 and 20
um silicate feature strengths/shapes are consistent with source-to-source
variations in grain size. A large fraction of the features are weak and flat,
consistent with um-sized grains indicating fast grain growth (from 0.1--1.0 um
in radius). In addition, approximately half of the T Tauri star spectra show
crystalline silicate features near 28 and 33 um indicating significant
processing when compared to interstellar grains. A few sources show large
10-to-20 um ratios and require even larger grains emitting at 20 um than at 10
um. This size difference may arise from the difference in the depth into the
disk probed by the two silicate emission bands in disks where dust settling has
occurred. The 10 um feature strength vs. shape trend is not correlated with age
or Halpha equivalent width, suggesting that some amount of turbulent mixing and
regeneration of small grains is occurring. The strength vs. shape trend is
related to spectral type, however, with M stars showing significantly flatter
10 um features (larger grain sizes) than A/B stars. The connection between
spectral type and grain size is interpreted in terms of the variation in the
silicate emission radius as a function of stellar luminosity, but could also be
indicative of other spectral-type dependent factors (e.g, X-rays, UV radiation,
stellar/disk winds, etc.).


title:
An unbiased search for the signatures of protostars in the rho Ophiuchi
  Molecular Cloud. II. Millimetre continuum observations

abstract:
  We have performed a 1 square degree 1.2mm dust continuum survey in the rho
Oph molecular cloud. We detect a number of previously unknown sources, ranging
from extended cores over compact, starless cores to envelopes surrounding young
stellar objects of Class 0, Class I, and Class II type. We analyse the mass
distribution, spatial distribution and the potential equilibrium of the cores.
For the inner regions, the survey results are consistent with the findings of
previous narrower surveys. The core mass function resembles the stellar initial
mass function, with the core mass function shifted by a factor of two to higher
masses (for the chosen opacity and temperature). In addition, we find no
statistical variation in the core mass function between the crowded inner
regions and those in more isolated fields except for the absence of the most
massive cores in the extended cloud. The inner region contains compacter cores.
This is interpreted as due to a medium of higher mean pressure although strong
pressure variations are evident in each region. The cores display a
hierarchical spatial distribution with no preferred separation scale length.
However, the frequency distribution of nearest neighbours displays two peaks,
one of which at 5000AU can be the result of core fragmentation. The
orientations of the major axes of cores are consistent with an isotropic
distribution. In contrast, the relative orientations of core pairs are
preferentially in the NW-SE direction on all separation scales. These results
are consistent with core production and evolution in a turbulent environment.
We report a new low-mass Class 0 object and its CO outflow.


title: A Spitzer Search for Infrared Excesses around Massive Young White Dwarfs

abstract:
  We examine 14 hot white dwarfs for signs of infrared excess using the Spitzer
Space Telescope. Twelve of the objects are massive white dwarfs which have been
suggested to be the result of binary mergers. The remaining two objects are
undermassive white dwarfs which again may be the result of mergers or the
inspiral of a substellar companion. In no case do we find any evidence for
significant infrared excesses out to wavelengths of 8 microns. This places
strong constraints on the presence of orbiting dust and weaker constraints on
the presence of close substellar companions.


title:
Observational characteristics of dense cores with deeply embedded young
  protostars

abstract:
  Class 0 objects, which are thought to be the youngest protostars, are
identified in terms of NIR or radio emission and/or the presence of molecular
outflows. We present combined hydrodynamic and radiative transfer simulations
of the collapse of a star-forming molecular core, which suggest two criteria
for identifying dense cores with deeply embedded very young protostars that may
not be observable in the NIR or radio with current telescopes. We find that
cores with protostars are relatively warm (T>15K) with their SEDs peaking at
wavelengths <170 micron, and they tend to appear circular.


title: The X-ray Telescope on board Swift: status and main results

abstract:
  The X-ray Telescope (XRT), on board the {\it Swift} satellite, provides:
automated source detection and position with few arcsecond accuracy within few
seconds from target acquisition; CCD spectroscopy and imaging capability
(0.2-10 keV), with the capability of detecting a milliCrab source in about 10
seconds; automatic adjusting of the CCD readout mode to optimize the science
return as the source fades. Swift main scientific goal is the study of
gamma-ray burst (GRBs). XRT can observe GRB afterglows over several orders of
magnitude in flux. The first results obtained during the first ten months of
operation confirm that XRT is fully compliant with the requirements and is
providing excellent results. In particular it is detecting a very steep decay
in the early X-ray light curve of many afterglows. Often there are also strong
flares superimposed to the X-ray light curve, probably related to the continued
internal engine activity. XRT is also localising for the first time the X-ray
counterparts to short bursts.


title:
A Catalog of Luminous Infrared Galaxies in the IRAS Survey and the
  Second Data Release of the SDSS

abstract:
  We select the Luminous Infrared Galaxies by cross-correlating the Faint
Source Catalogue (FSC) and Point Source Catalogue (PSC) of the IRAS Survey with
the Second Data Release of the SDSS for studying their infrared and optical
properties. The total number of our sample is 1267 for FSC and 427 for PSC by
using 2$\sigma$ significance level cross-section. The "likelihood ratio" method
is used to estimate the sample's reliability and for a more reliable subsample
(908 for FSC and 356 for PSC) selection. Then a Catalog with both the infrared,
optical and radio informations is presented and will be used in further works.
Some statistical results show that the Luminous Infrared Galaxies are quite
different from the Ultra-Luminous Infrared Galaxies. The AGN fractions of
galaxies with different infrared luminosities and the radio to infrared
correlations are consist with previous studies.


title:
Ground-based Gamma-Ray Observations of Pulsars and their Nebulae:
  Towards a New Order

abstract:
  The excellent sensitivity and high resolution capability of wide FoV
ground-based imaging atmospheric Cerenkov telescopes allow us for the first
time to resolve the morphological structures of pulsar wind nebulae (PWN) which
are older and more extended than the Crab Nebula. VHE gamma-ray observations of
such extended nebulae (with field strengths below ~ 20 micro Gauss) probe the
electron component corresponding to the unseen extreme ultraviolet (EUV)
synchrotron component, which measures electron injection from earlier
evolutionary epochs. VHE observations of PWN therefore introduce a new window
on PWN research. This review paper also identifies conditions for maximal VHE
visbility of PWN. Regarding pulsar pulsed emission, it is becoming clear that
the threshold energies of current telescopes are not sufficient to probe the
pulsed gamma-ray component from canonical pulsars. Theoretical estimates of
pulsed gamma-ray emission from millisecond pulsars seem to converge and it
becomes clear that such detections with current 3rd generation telescopes will
not be possible, unless the geometry is favourable.


title:
High precision determination of the atmospheric parameters and
  abundances of the COROT main targets

abstract:
  One of the main goals of the COROT mission is to get precise photometric
observations of selected bright stars in order to allow the modelling of their
interior through asteroseismology. However, in order to interpret the
asteroseismological data, the effective temperature, surface gravity, and
chemical composition of the stars must be known with sufficient accuracy. To
carry out this task, we have developed a spectroscopic method called APASS
(Atmospheric Parameters and Abundances from Synthetic Spectra) which allows
precise analysis of stars with a moderate to high rotational velocity, which is
the case for most primary COROT targets. Our method is based on synthetic
spectra and works differentially with respect to the Sun. Using high
signal-to-noise spectra and the APASS method, we determined the atmospheric
parameters and chemical abundances of 13 primary COROT targets. Our results
agree well with those obtained by Bruntt using his software VWA and with those
obtained with the software TEMPLOGG. However, in both cases, our error bars are
significantly smaller than those of other methods. Our effective temperatures
are also in excellent agreement with those obtained with the IR photometry
method. For five stars with relatively low rotational velocity, we also
performed an analysis with a classical equivalent-width method to test
agreement with APASS results. We show that equivalent-width measurements by
Gaussian or Voigt profile-fitting are sensitive to the rotational broadening,
leading to systematic errors whenever the projected rotation velocity is
non-negligible. The APASS method appears superior in all cases and should thus
be preferred.


title:
FUSE and HST/STIS far-ultraviolet observations of AM Herculis in an
  extended low state

abstract:
  We have obtained FUSE and HST/STIS time-resolved spectroscopy of the polar AM
Herculis during a deep low state. The spectra are entirely dominated by the
emission of the white dwarf. Both the far-ultraviolet (FUV) flux as well as the
spectral shape vary substantially over the orbital period, with maximum flux
occurring at the same phase as during the high state. The variations are due to
the presence of a hot spot on the white dwarf, which we model quantitatively.
The white dwarf parameters can be determined from a spectral fit to the faint
phase data, when the hot spot is self-eclipsed. Adopting the distance of
79+8-6pc determined by Thorstensen, we find an effective temperature of
19800+-700K and a mass of Mwd=0.78+0.12-0.17Msun. The hot spot has a lower
temperature than during the high state, ~34000-40000K, but covers a similar
area, ~10% of the white dwarf surface. Low state FUSE and STIS spectra taken
during four different epochs in 2002/3 show no variation of the FUV flux level
or spectral shape, implying that the white dwarf temperature and the hot spot
temperature, size, and location do not depend on the amount of time the system
has spent in the low state. Possible explanations are ongoing accretion at a
low level, or deep heating, both alternatives have some weaknesses that we
discuss. No photospheric metal absorption lines are detected in the FUSE and
STIS spectra, suggesting that the average metal abundances in the white dwarf
atmosphere are lower than 1e-3 times their solar values.


title: X-ray binaries in Sculptor

abstract:
  We report the results of a deep Chandra survey of the Sculptor dwarf
spheroidal galaxy. We find five X-ray sources with L_X of at least 6*10^33
ergs/sec with optical counterparts establishing them as members of Sculptor.
These X-ray luminosities indicate that these sources are X-ray binaries, as no
other known class of Galactic point sources can reach 0.5-8 keV luminosities
this high. Finding these systems proves definitively that such objects can
exist in an old stellar population without stellar collisions. Three of these
objects have highly evolved optical counterparts (giants or horizontal branch
stars), as do three other sources whose X-ray luminosities are in the range
which includes both quiescent low mass X-ray binaries and the brightest
magnetic cataclysmic variables. Large area surveys should also turn up large
numbers of quiescent X-ray binaries. (Modified)


title: NIR Imaging and Spectroscopy of AGN hosts at z < 0.06

abstract:
  We created a sample of nearby QSOs selected from the Hamburg/ESO survey and
the Veron-Cetty & Veron catalog, with a limiting redshift of z<0.06, which
consists of 63 objects. In this contribution, we present the results of our
ISAAC Ks-band spectroscopic and H and Ks-band photometric observations of 9
sources of this sample. In seven sources we find hydrogen recombination lines
Paalpha and Brgamma of which five galaxies show a broad component. In three
sources, extended molecular hydrogen emission is detected in the 1-0S(1) line.
The stellar CO-absorption feature is only detectable in 5 objects, those
sources with J-H and H-K colors closest to those of ordinary galaxies.


title:
A new XMM-Newton observation of Pictor A radio lobes confirms the
  non-thermal origin of the X-ray emission

abstract:
  X-ray emission from the eastern radio lobe of the FRII Radio Galaxy Pictor A
was serendipitously discovered by a short observation of XMM-Newton in 2001.
The X-ray spectrum, accumulated on a region covering about half of the entire
radio lobe, was well described by both a thermal model and a power law, making
non-univocal the physical interpretation. A new XMM-Newton observation
performed in 2005 has allowed the detection of the X-ray emission from both
radio lobes and unambiguously revealed its non-thermal origin. The X-ray
emission is due to Inverse Compton (IC) of the cosmic microwave background
photons by relativistic electrons in the lobe. We confirm the discrepancy
between the magnetic field, as deduced from the comparison of the IC X-ray and
radio fluxes, and the equipartition value.


title: Aperture calculation of the Pierre Auger Observatory surface detector

abstract:
  We determine the instantaneous aperture and integrated exposure of the
surface detector of the Pierre Auger Observatory, taking into account the
trigger efficiency as a function of the energy, arrival direction (with zenith
angle lower than 60 degrees) and nature of the primary cosmic-ray. We make use
of the so-called Lateral Trigger Probability function (or LTP) associated with
an extensive air shower, which summarizes all the relevant information about
the physics of the shower, the water tank Cherenkov detector, and the triggers.


title: Tracing the first stars with cosmic infrared background fluctuations

abstract:
  The deepest space and ground-based observations find metal-enriched galaxies
at cosmic times when the Universe was <1 Gyr old. These stellar populations had
to be preceded by the metal-free first stars, Population III. Recent cosmic
microwave background polarization measurements indicate that stars started
forming early when the Universe was $\lsim200$ Myr old. Theoretically it is now
thought that Population III stars were significantly more massive than the
present metal-rich stellar populations. While such sources will not be
individually detectable by existing or planned telescopes, they would have
produced significant cosmic infrared background radiation in the near-
infrared, whose fluctuations reflect the conditions in the primordial density
field. Here we report a measurement of diffuse flux fluctuations after removing
foreground stars and galaxies. The anisotropies exceed the instrument noise and
the more local foregrounds and can be attributed to emission from massive
Population III stars, providing observational evidence of an era dominated by
these objects.


title: Strange Pulsar Hypothesis

abstract:
  It appears that there is a genuine shortage of radio pulsars with surface
magnetic fields significantly smaller than $\sim 10^8$ Gauss. We propose that
the pulsars with very low magnetic fields are actually strange stars locked in
a state of minimum free energy and therefore at a limiting value of the
magnetic field which can not be lowered by the system spontaneously.


title: XRT Light curves: Morphology, Flares and Energy

abstract:
  Following a brief introduction we show that the observations obtained so far
with the Swift satellite begin to shed light over a variety of problems that
were left open following the excellent performance and related discoveries of
the Italian - Dutch Beppo SAX satellite. The XRT light curves show common
characteristics that are reasonably understood within the framework of the
fireball model. Unforeseen flares are however detected in a large fraction of
the GRB observed and the energy emitted by the brightest ones may be as much as
85% of the total soft X ray emission measured by XRT. These characteristics
seems to be common to long and short bursts.


title: Gamma Ray Bursts: recent results obtained by the SWIFT mission

abstract:
  In the introduction we give the main characteristics of the Swift mission
outlining how the design was driven by the science goals and by the heritage we
got from the Italian - Dutch satellite Beppo SAX. We show some of the new
characteristics of the X - ray light curves that became evident soon after we
obtained the first set of data. In addition to the early phase steep slope
afterglow discovered by Swift, we discuss the frequently observed GRB flares
and the first localization of a short burst.


title: Microstructures of planetary nebulae with large telescopes

abstract:
  Planetary nebulae (PNe) are known to possess a variety of small-scale
structures that are usually in a lower ionization state than the main body of
the nebulae. The morphological and kinematic properties of these low-ionization
structures (LISs) vary from type to type in the sense that LISs can appear in
the form of pairs of knots, filaments, jets, and isolated features moving with
velocities that either do not differ substantially from that of the ambient
nebula, or instead move supersonically through the environment. The
high-velocity jets and pairs of knots, also known as FLIERs, are likely to be
shock-excited. So far, most of the FLIERs analyzed with ground-based small and
medium telescopes, as well as with the HST, do not show the expected
shock-excited features --either the bow-shock geometry or the shock excited
emission lines. In this talk we discuss the crucial problem of the excitation
mechanisms of FLIERs --through the comparison of jets and knots of NGC 7009 and
K 4-47-- and what might be the contribution of large telescopes.


title: Diffuse Radio Sources in Groups and Poor Clusters

abstract:
  We have discovered new diffuse radio sources likely associated with groups of
galaxies at low redshift (0.01-0.04) and without apparent AGN by using the
WENSS and WISH catalogs to perform an unbiased survey. These sources resemble
the radio halos, mini-halos, and 'relics' of rich clusters, which are thought
to be powered by shocks and turbulence from infall into their deep potential
wells. Our detection of similar sources within the shallow potential wells of
groups of galaxies challenges this model. Their radio luminosities are
approximately two orders of magnitude higher than expected from the
extrapolation of the apparent rich cluster radio/X-ray luminosity relation.
Even if these sources are misidentified distant clusters, they would lie above
the apparent rich cluster radio/X-ray luminosity relation in the literature,
suggesting that detections of radio halos and relics thus far may be more
biased than previously thought.


title: Do we really know how to derive the basic PNe parameters?

abstract:
  How well do we know the physical/chemical properties of PNe? 1D (CLOUDY) and
3D (MOCASSIN) photoionisation codes are used in this contribution to model the
PNe K 4-47 and NGC 7009 as an attempt to question whether or not the high Te
(higher than 21,000K) of the K 4-47's core and the N overabundance of the outer
knots in NGC 7009 are real.
  These are very basic parameters, obtained for Galactic PNe, e.g. nearby
objects, even though with large uncertainties. Based on the comparison of the
modelling with, mainly, optical images and long-slit spectroscopic data, it is
suggested here that K 4-47 high Te can be explained if its core is composed of
a very dense and small inner region --that matches the radio measurements-- and
a lower density outer core --matching the optical observations. This approach
can account for the strong auroral emission lines [OIII]4363A and [NII]5755A
observed, and so for the high temperatures. This teaches us that the assumption
of a homogeneous distribution of the gas is completely wrong for the core of
such PN.
  In the case of NGC 7009 a simple 3D model that reproduces the observed
geometry of this nebula is constructed. The aim of this modelling was to
explore the possibility that the enhanced [NII] emission observed in the outer
knots may be due to ionisation effects instead to a local N overabundance. Here
it is discussed the model that can best reproduce the observations employing a
homogeneous set of abundances throughout the nebula, not only for nitrogen but
also for all the other elements considered.


title:
Evidence for a high energy curvature in the XMM-Newton spectrum of the
  ULX NGC1313 X-1

abstract:
  ASCA X-ray spectra of many ULXs were described in terms of optically thick
emission from hot (kT ~1-2keV) accretion disks, while recent XMM-Newton and
Chandra observations have revealed a cool (kT ~0.2keV), soft X-ray excess
emission from a number of them. Here we utilize improved calibration and high
signal-to-noise XMM-Newton spectra of NGC1313 X-1 to present evidence for a
cool (~0.2keV) soft excess and a curved or a cutoff power-law (Gamma ~1-1.5,
E_cutoff ~3-8keV). The high energy curvature may also be described by a hot
(~1-2.5keV) multicolor disk blackbody. The soft excess emission is unlikely to
arise from a cool disk as its blackbody temperature is similar in three
XMM-Newton observations, despite a change in the observed flux by a factor of
about two. Thus, previous estimates of the black hole mass of 1000Msun for
NGC1313 X-1 based on the temperature of the soft excess emission is unlikely to
be correct. The power-law cutoff energy is found to decrease from ~8keV to
\~3keV when the ULX brightened by a factor of about two. The unusual spectral
properties of NGC1313 X-1 are difficult to understand in the framework of the
disk/corona models generally adopted for the black hole binaries or active
galactic nuclei and may require to invoke super-critical accretion rates.


title: Unbiased Studies of Diffuse Extragalactic Radio Sources

abstract:
  We present an overview of unbiased studies of diffuse extragalactic radio
sources. We use a previously developed filtering technique to remove compact
sources from large surveys such as WENSS, WISH, and NVSS and examine the
residual diffuse emission. A search of these residuals, unbiased by optical or
X-ray selection, has uncovered a wide variety of diffuse sources, including
those associated with groups of galaxies, ``blank'' fields, and previously
unrecognized diffuse radio galaxy emission, as well as halos and relics of rich
clusters. A second, targeted survey of the brightest X-ray clusters results in
a number of new sources, and illuminates some important selection effects. When
the well-established relationship between X-ray and radio halo luminosities is
extrapolated to lower levels, the apparent correlation holds quite well for any
type of diffuse source, even background noise. The observed correlations must
therefore be scrutinized for possible selection effects before physical
interpretations are made. We briefly mention a wide-field mapping project to
search for large-scale structures, and goals for the next generation of studies
in magnetic field - angular size parameter space.


title:
On the nitrogen abundance of FLIERs: the outer knots of the planetary
  nebula NGC 7009

abstract:
  We have constructed a 3D photoionisation model of a planetary nebula (PN)
similar in structure to NGC 7009 with its outer pair of knots (also known as
FLIERs --fast, low-ionization emission regions). The work is motivated by the
fact that the strong [N II]6583A line emission from FLIERs in many planetary
nebulae has been attributed to a significant local overabundance of nitrogen.
We explore the possibility that the apparent enhanced nitrogen abundance
previously reported in the FLIERs may be due to ionization effects. Our model
is indeed able to reproduce the main spectroscopic and imaging characteristics
of NGC 7009's bright inner rim and its outer pairs of knots, assuming
homogeneous elemental abundances throughout the nebula, for nitrogen as well as
all the other elements included in the model. Because of the fact that the
(N+/N)/(O+/O) ratio predicted by our models are 0.60 for the rim and 0.72 for
the knots, so clearly in disagreement with the N+/N=O+/O assumption of the
ionization correction factors method (icf), the icfs will be underestimated by
the empirical scheme, in both components, rim and knots, but more so in the
knots. This effect is partly responsible for the apparent inhomogeneous N
abundance empirically derived. The differences in the above ratio in these two
components of the nebula may be due to a number of effects including charge
exchange --as pointed out previously by other authors-- and the difference in
the ionization potentials of the relevant species --which makes this ratio
extremely sensitive to the shape of the local radiation field. Because of the
latter, a realistic density distribution is essential to the modelling of a
non-spherical object, if useful information is to be extracted from spatially
resolved observations, as in the case of NGC 7009.


title: IGR J17252-3616: an accreting pulsar observed by INTEGRAL and XMM-Newton

abstract:
  The discovery of the X-ray source IGR J17252-3616 by INTEGRAL was reported on
9 February 2004. Regular monitoring by INTEGRAL shows that IGR J17252-3616 is a
persistent hard X-ray source with an average count rate of 0.96 counts/s (~6.4
mCrab) in the 20-60 keV energy band. A follow-up observation with XMM-Newton,
which was performed on 21 March 21 2004, showed that the source is located at
R.A.(2000.0)=17h25m11.4 and Dec.=-36degr16'58.6" with an uncertainty of 4". The
only infra-red counterpart to be found within the XMM-Newton error circle was
2MASS J17251139-3616575, which has a Ks-band magnitude of 10.7 and is located
1" away from the XMM-Newton position.
  The analysis of the combined INTEGRAL and XMM-Newton observations shows that
the source is a binary X-ray pulsar with a spin period of 413.7 s and an
orbital period of 9.72 days. The spectrum can be fitted with a flat power law
plus an energy cut off (Gamma~0.02,Ecut~8.2 keV) or a Comptonized model
(kTe~5.5 keV, tau~7.8). The spectrum also indicates a large hydrogen column
density of Nh~15x1e22 atoms/cm-2 suggesting an intrinsic absorption. The Fe
Kalpha line at 6.4 keV is clearly detected. Phase-resolved spectroscopy does
not show any variation in the continuum except the total emitted flux. The
absorption is constant along the pulse phase. This source can be associated
with EXO 1722-363 as both systems show common timing and spectral features. The
observations suggest that the source is a wind-fed accreting pulsar accompanied
by a supergiant star.


title: AGN Feedback Causes Downsizing

abstract:
  We study the impact of outflows driven by active galactic nuclei (AGN) on
galaxy formation. Outflows move into the surrounding intergalactic medium (IGM)
and heat it sufficiently to prevent it from condensing onto galaxies. In the
dense, high-redshift IGM, such feedback requires highly energetic outflows,
driven by a large AGN. However, in the more tenuous low-redshift IGM,
equivalently strong feedback can be achieved by less energetic winds (and thus
smaller galaxies). Using a simple analytic model, we show that this leads to
the anti-hierarchical quenching of star-formation in large galaxies, consistent
with current observations. At redshifts prior to the formation of large AGN,
galaxy formation is hierarchical and follows the growth of dark-matter halos.
The transition between the two regimes lies at the z ~ 2 peak of AGN activity.


title: Quasars in the MAMBO blank field survey

abstract:
  Our MAMBO 1.2 mm blank field imaging survey of ~0.75 sqd has uncovered four
unusually bright sources, with flux densities between 10 and 90 mJy, all
located in the Abell 2125 field. The three brightest are flat spectrum radio
sources with bright optical and X-ray counterparts. Their mm and radio flux
densities are variable on timescales of months. Their X-ray luminosities
classify them as quasars. The faintest of the four mm bright sources appears to
be a bright, radio-quiet starburst at z~3, similar to the sources seen at lower
flux densities in the MAMBO and SCUBA surveys. It may also host a mildly
obscured AGN of quasar-like X-ray luminosity. The three non-thermal mm sources
imply an areal density of flat spectrum radio sources higher by at least 7
compared with that expected from an extrapolation of the lower frequency radio
number counts.


title:
Stellar mass loss and the Intra-Cluster Medium in Galactic globular
  clusters: a deep radio survey for HI and OH

abstract:
  We present the results of a survey, the deepest to date, for HI emission at
21 cm and OH emission at 18 cm (lines at 1612, 1665, 1667 and 1720 MHz) in the
direction towards the Galactic globular clusters M 15, M 2, NGC 6934, NGC 7006
and Pal 13. The aim is to measure the amount of hydrogen in the intra-cluster
medium (ICM), and to find OH masers in the circumstellar envelopes of globular
cluster red giants. We present a tentative detection of 0.3 Msun of neutral
hydrogen in M 15 and possible detections of neutral hydrogen in M 2 and Pal 13.
We derive upper limits to the neutral hydrogen content of NGC 6934 and NGC
7006. No OH emission is detected. We also present deep HI data of the northern
tip of the Magellanic Stream behind Pal 13.


title:
Metallicity and Nuclear Star Formation in Nearby Galaxy Pairs: Evidence
  for Tidally Induced Gas Flows

abstract:
  We derive the first luminosity-metallicity relation for a large objectively
selected sample of local galaxy pairs and we compare the pairs LZ relation with
the relation for the Nearby Field Galaxy Survey (NFGS). Galaxy pair members
with small projected separations (s<20 kpc/h) have systematically lower
metallicities (~0.2 dex on average) than the field galaxies, or than more
widely separated pairs at the same luminosity. There is a strong correlation
between metallicity and central burst strength in the galaxy pairs. All five
galaxies in the pairs sample with strong central bursts have close companions
and metallicities lower than the comparable field galaxies. Our results provide
strong observational evidence for a merger scenario where galaxy interactions
cause gas flows towards the central regions, carrying less enriched gas from
the outskirts of the galaxy into the central regions. The less enriched gas
dilutes the pre-existing nuclear gas to produce a lower metallicity than would
be obtained prior to the interaction. These gas flows trigger central bursts of
star formation, causing strong central burst strengths, and possibly aiding the
formation of blue bulges. We show that the timescale and central gas dilution
required by this scenario are consistent with predictions from hydrodynamic
merger models.


title: A Classical Treatment of Island Cosmology

abstract:
  Computing the perturbation spectrum in the recently proposed Island Cosmology
remains an open problem. In this paper we present a classical computation of
the perturbations generated in this scenario by assuming that the NEC-violating
field behaves as a classical phantom field. Using an exactly-solvable
potential, we show that the model generates a scale-invariant spectrum of
scalar perturbations, as well as a scale-invariant spectrum of gravitational
waves. The scalar perturbations can have sufficient amplitude to seed
cosmological structure, while the gravitational waves have a vastly diminished
amplitude.


title: Gravitational Lensing & Stellar Dynamics

abstract:
  Strong gravitational lensing and stellar dynamics provide two complementary
and orthogonal constraints on the density profiles of galaxies. Based on
spherically symmetric, scale-free, mass models, it is shown that the
combination of both techniques is powerful in breaking the mass-sheet and
mass-anisotropy degeneracies. Second, observational results are presented from
the Lenses Structure & Dynamics (LSD) Survey and the Sloan Lens ACS (SLACS)
Survey collaborations to illustrate this new methodology in constraining the
dark and stellar density profiles, and mass structure, of early-type galaxies
to redshifts of unity.


title:
Stellar Populations of Elliptical Galaxies in Virgo Cluster I. : The
  Data and Stellar Population Analysis

abstract:
  We have determined spectroscopic ages of elliptical galaxies in the Virgo
cluster using spectra of very high signal-to-noise ratio (S/N/A > 100). We
observed 8 galaxies with the Subaru Telescope and have combined this sample
with 6 galaxies previously observed with the WHT. To determine their ages we
have used a new method based on the Hgamma_sigma age indicator, which is
virtually independent of the effects of metallicity. Apart from ages we have
estimated abundances of various elements. In this paper we present the
observations, the data reduction and the reliability of the Hgamma_sigma
method. The results of this investigation are presented in a companion paper
(Yamada et al. 2006).


title: A unified accretion-ejection paradigm for Black Hole X-ray Binaries

abstract:
  We present a new picture for the central regions of Black Hole X-ray
Binaries. In our view, these central regions have a multi-flow configuration
which consists in (1) an outer standard accretion disc down to a transition
radius r_J, (2) an inner magnetized accretion disc below r_J driving (3) a non
relativistic self-collimated electron-proton jet surrounding, when adequate
conditions for pair creation are met, (4) a ultra relativistic
electron-positron beam. This accretion-ejection paradigm provides a simple
explanation to the canonical spectral states by varying the transition radius
r_J and disc accretion rate independently. Large values of r_J correspond to
the Quiescent state for low $\dot m$ and the Hard state for larger $\dot m$.
These states are characterized by the presence of a steady electron-proton MHD
jet emitted by the disc below r_J. The hard X-ray component is expected to form
at the jet basis. When r_j becomes smaller than the marginally stable orbit
r_i, the whole disc resembles a standard accretion disc, characteristic of the
Soft state. Intermediate states correspond to situations where r_J ~ r_i. At
large $\dot m$, an unsteady pair cascade process is triggered within the jet
axis, giving birth to ejection of relativistic pair blobs. This would
correspond to the luminous intermediate state, with its associated superluminal
motions. The variation of r_J independently of $\dot m$ is a necessary
ingredient in this picture, arising from the presence of a large scale vertical
magnetic field threading the disc.


title: Comments on Long-Wavelength Backreaction and Dark Energy

abstract:
  In this brief note we comment on a recent attempt by Martineau and
Brandenberger (astro-ph/0510523) to explain the acceleration of the Universe
using the back-reaction of long-wavelength perturbations associated with
isocurvature perturbation modes.


title:
Prospects for population synthesis in the H band: NeMo grids of stellar
  atmospheres compared to observations

abstract:
  For applications in population synthesis, libraries of theoretical stellar
spectra are often considered an alternative to template libraries of observed
spectra, because they allow a complete sampling of stellar parameters. Most
attention in published theoretical spectral libraries has been devoted to the
visual wavelength range. We present a detailed comparison of theoretical
spectra in the range 1.57-1.67$\mu$m, for spectral types from A to early M and
for giants and dwarf stars, with observed stellar spectra at resolutions around
3000, which would be sufficient to disentangle the different groups of late
type stars. We have selected the NeMo grids of stellar atmospheres to perform
such a comparison. We first demonstrate that after combining atomic and
molecular line lists, it is possible to match observed spectral flux
distributions with theoretical ones very well for almost the entire parameter
range covered by the NeMo grids at moderate resolution in the visual range. In
the infrared range, although the overall shape of the observed flux
distributions is still matched reasonably well, the individual spectral
features are reproduced by the theoretical spectra only for stars earlier than
mid F type. For later spectral types the differences increase and theoretical
spectra of K type stars have systematically weaker line features than those
found in observations. These discrepancies are traced back to stem primarily
from incomplete data on neutral atomic lines, although some of them are also
related to molecules. Improving atomic data in the near infrared is a key
element in making the construction of reliable libraries of stellar spectra in
the infrared feasible.


title: Solar Gravity Modes: Present and Future

abstract:
  Gravity modes are the best probes to study the solar radiative zone dynamics,
especially in the nuclear core. These modes remain difficult to observe, but
they are essential ingredients for progressing on the evolution of the
Sun-Earth relationship at the level of centuries. Today, the knowledge of the
internal dynamics comes from acoustic modes and concerns mainly the external 2%
of the solar mass. Nevertheless, the flat rotation profile of the radiative
zone compels physics beyond the standard framework. I summarize different
attempts to look for gravity modes and the results obtained after 8 years of
observation with the GOLF/SoHO instrument. Some gravity mode candidates (at
1mm/s level) have appeared with more than 98% confidence level as quadruplets
or quintuplets. These patterns, if confirmed as gravity modes, may reveal very
exciting physics of the solar core. Getting information on rotation and
magnetic field in the solar core are real keys to simulate a complete dynamical
solar picture. The understanding of the solar dynamics, the precise energetic
balance and its temporal evolution necessitate more observations of the
radiative zone which constitutes 98% of the Sun by mass. Our expertise in
Doppler velocity measurements allows a step further and a new instrumental
concept to reach velocities as low as 0.1 mm/s. A prototype will join the
Tenerife site in 2006 and a space version is proposed to CNES and ESA as a
microsatellite or part of a payload at the L1 Lagrange point.


title: Theoretical Uncertainties in Inflationary Predictions

abstract:
  With present and future observations becoming of higher and higher quality,
it is timely and necessary to investigate the most significant theoretical
uncertainties in the predictions of inflation. We show that our ignorance of
the entire history of the Universe, including the physics of reheating after
inflation, translates to considerable errors in observationally relevant
parameters. Using the inflationary flow formalism, we estimate that for a
spectral index $n$ and tensor/scalar ratio $r$ in the region favored by current
observational constraints, the theoretical errors are of order $\Delta n / | n
- 1| \sim 0.1 - 1$ and $\Delta r /r \sim 0.1 - 1$. These errors represent the
dominant theoretical uncertainties in the predictions of inflation, and are
generically of the order of or larger than the projected uncertainties in
future precision measurements of the Cosmic Microwave Background. We also show
that the lowest-order classification of models into small field, large field,
and hybrid breaks down when higher order corrections to the dynamics are
included. Models can flow from one region to another.


title: RR Lyrae-based calibration of the Globular Cluster Luminosity Function

abstract:
  We test whether the peak absolute magnitude Mv(TO) of the Globular Cluster
Luminosity Function (GCLF) can be used for reliable extragalactic distance
determinations. Starting with the luminosity function of the Galactic Globular
Clusters listed in Harris catalog, we determine Mv(TO) either using current
calibrations of the absolute magnitude Mv(RR) of RR Lyrae stars as a function
of the cluster metal content [Fe/H] and adopting selected cluster samples. We
show that the peak magnitude is slightly affected by the adopted Mv(RR)-[Fe/H]
relation, while it depends on the criteria to select the cluster sample. As for
the GCLFs in other external galaxies, using Surface Brightness Fluctuations
(SBF) measurements we give evidence that the luminosity functions of the blue
(metal-poor) Globular Clusters peak at the same luminosity within ~0.2 mag,
whereas for the red (metal-rich) samples the agreement is within ~0.5 mag even
accounting for the theoretical metallicity correction expected for clusters
with similar ages and mass distributions. Then, using the SBF absolute
magnitudes provided by a Cepheid distance scale calibrated on a fiducial
distance to LMC (m(LMC)=18.50 mag), we show that the Mv(TO) value of the
metal-poor clusters in external galaxies(-7.67+/-0.23 mag) is in excellent
agreement with the value of both Galactic (-7.66+/-0.11 mag) and M31
(-7.65+/-0.19 mag)ones.


title: A novel technique for wide-field polarimetry with a radiotelescope array

abstract:
  We report the use of the Australia Telescope Compact Array (ATCA) to conduct
polarimetric observations of the sky at 5 GHz. The ATCA is normally operated as
an interferometer array, but these observations were conducted in a split array
mode in which the antenna elements were used as single-dishes with their beams
staggered to simultaneously cover a wide area of sky with a resolution of 10
arcmin. The linearly polarized sky radiation was fully characterized from
measurements, made over a range of parallactic angles, of the cross correlated
signals from the orthogonal linear feeds. We describe the technique and present
a polarimetric image of the Vela supernova remnant made as a test of the
method. The development of the techniques was motivated by the need for
wide-field imaging of the foreground contamination of the polarized component
of the cosmic microwave background signal.


title:
B and I-band optical micro-variability observations of the BL Lac
  objects S5 2007+777 and 3C371

abstract:
  We have observed S5 2007+777 and 3C371 in the B and I bands for 13 and 8
nights, respectively, during various observing runs in 2001, 2002 and 2004. The
observations resulted in almost evenly sampled light curves, 6-9 hours long. We
do not detect any flares within the observed light curves, but we do observe
small amplitude, significant variations, in both bands, on time scales of hours
and days. The average variability amplitude on time scales of minutes/hours is
2.5% and 1-1.5% in the case of S5 2007+777 and 3C371, respectively. The average
amplitudes increase to 5-12% and 4-6%, respectively, on time scales of days. We
find that the B and I band variations are highly correlated, on both short and
long time scales. During the 2004 observations, which resulted in the longest
light curves, we observe two well defined flux-decay and rising trends in the
light curves of both objects. When the flux decays, we observe significant
delays, with the B band flux decaying faster than the flux in the I band. As a
result, we also observe significant, flux related spectral variations as well.
The flux-spectral relation is rather complicated, with loop-like structures
forming during the flux evolution. The presence of spectral variations imply
that the observed variability is not caused by geometric effects. On the other
hand, our results are fully consistent with the hypothesis that the observed
variations are caused by perturbations which affect different regions in the
jet of the sources.


title: Physical constants and the Gurzadyan-Xue formula for the dark energy

abstract:
  We consider cosmological implications of the formula for the dark energy
density derived by Gurzadyan and Xue which predicts a value fitting the
observational one. Cosmological models with varying by time physical constants,
namely, speed of light and gravitational constant and/or their combinations,
are considered. In one of the models, for example, vacuum energy density
induces effective negative curvature, while another one has an unusual
asymptotic. This analysis also explicitely rises the issue of the meaning and
content of physical units and constants in cosmological context.


title: Prompt optical observations of GRB050319 with the Swift UVOT

abstract:
  The UVOT telescope on the Swift observatory has detected optical afterglow
emission from GRB 050319. The flux declines with a power law slope of alpha =
-0.57 between the start of observations some 230 seconds after the burst onset
(90s after the burst trigger) until it faded below the sensitivity threshold of
the instrument after ~5 x 10^4s. There is no evidence for the rapidly declining
component in the early light curve that is seen at the same time in the X-ray
band. The afterglow is not detected in UVOT shortward of the B-band, suggesting
a redshift of about 3.5. The optical V-band emission lies on the extension of
the X-ray spectrum, with an optical to X-ray slope of beta = -0.8. The
relatively flat decay rate of the burst suggests that the central engine
continues to inject energy into the fireball for as long as a few x 10^4s after
the burst.


title:
A new sample of broad-absorption-line quasars exhibiting the ghost of
  lyman alpha

abstract:
  We have searched the broad-absorption-line quasar (BAL QSO) sample presented
by Reichard et al. for objects exhibiting the so-called `ghost of Lyman alpha'.
This ghost manifests as a hump near -5900kms in the troughs of the broad
absorption lines and provides strong evidence for the importance of
line-driving in powering the outflows from BAL QSOs. Of the 224 sample BAL QSOs
selected from the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR), 198
satisfy our redshift constraints and 58 show clear evidence of multiple-trough
(MT) structure in the CIV line. A composite spectrum constructed from this MT
sample already shows evidence for a ghost feature. Narrowing our classification
scheme further, we define a set of 36 objects that individually show evidence
of a ghost feature, and then apply further cuts to arrive at a final `best
sample' that contains our seven strongest ghost candidates. A further five
objects show evidence for a ghost feature that is almost strong enough to merit
inclusion in our best sample. Despite its limited size, our best sample more
than doubles the number of known BAL QSOs with clear ghost signatures and
should make an excellent basis for detailed follow-up studies.


title:
Spectrophotometric properties of galaxies at intermediate redshifts (z ~
  0.2--1.0) I. Sample description, photometric properties and spectral
  measurements

abstract:
  We present the spectrophotometric properties of a sample of 141 emission-line
galaxies at redshifts in the range $0.2<z<1.0$ with a peak around
$z\in[0.2,0.4]$. The analysis is based on medium resolution
($R\_{\mathrm{s}}=500-600$), optical spectra obtained at VLT and Keck. The
targets are mostly {} "Canada-France Redshift Survey" emission-line galaxies,
with the addition of field galaxies randomly selected behind lensing clusters.
We complement this sample with galaxy spectra from the {} "Gemini Deep Deep
Survey" public data release. We have computed absolute magnitudes of the
galaxies and measured the line fluxes and equivalent widths of the main
emission/absorption lines. The last two have been measured after careful
subtraction of the fitted stellar continuum using the \texttt{platefit}
software originally developed for the SDSS and adapted to our data. We present
a careful comparison of this software with the results of manual measurements.
The pipeline has also been tested on lower resolution spectra, typical of the
{} "VIMOS/VLT Deep Survey" ($R\_{\mathrm{s}}=250$), by resampling our medium
resolution spectra. We show that we can successfully deblend the most important
strong emission lines. These data are primarily used to perform a spectral
classification of the galaxies in order to distinguish star-forming galaxies
from AGNs. Among the initial sample of 141 emission-line galaxies, we find 7
Seyfert 2 (narrow-line AGN), 115 star-forming galaxies and 16 {} "candidate"
star-forming galaxies. Scientific analysis of these data, in terms of chemical
abundances, stellar populations, etc, will be presented in subsequent papers of
this serie.


title:
Spectrophotometric properties of galaxies at intermediate redshifts (z ~
  0.2--1.0) II. The Luminosity -- Metallicity relation

abstract:
  We present the gas-phase oxygen abundance (O/H) for a sample of 131
star-forming galaxies at intermediate redshifts ($0.2<z<1.0$). The sample
selection, the spectroscopic observations (mainly with VLT/FORS) and associated
data reduction, the photometric properties, the emission-line measurements, and
the spectral classification are fully described in a companion paper (Paper I).
We use two methods to estimate the O/H abundance ratio: the {} "standard"
$R\_{\mathrm{23}}$ method which is based on empirical calibrations, and the
CL01 method which is based on grids of photo-ionization models and on the
fitting of emission lines. For most galaxies, we have been able to solve the
problem of the metallicity degeneracy between the high- and low-metallicity
branches of the O/H vs. $R\_{\mathrm{23}}$ relationship using various secondary
indicators. The luminosity -- metallicity ($L-Z$) relation has been derived in
the $B$- and $R$-bands, with metallicities derived with the two methods
($R\_{\mathrm{23}}$ and CL01). In the analysis, we first consider our sample
alone and then a larger one which includes other samples of
intermediate-redshift galaxies drawn from the literature. The derived $L-Z$
relations at intermediate redshifts are very similar (same slope) to the $L-Z$
relation obtained for the local universe. Our sample alone only shows a small
evolution of the $L-Z$ relation with redshift up to $z\sim1.0$. We only find
statistical variations consistent with the uncertainty in the derived
parameters. Including other samples of intermediate-redshift galaxies, we find
however that galaxies at $z\sim1$ appear to be metal-deficient by a factor of
$\sim3$ compared with galaxies in the local universe. For a given luminosity,
they contain on average about one third of the metals locked in local galaxies.


title:
Atmospheric Chemistry in Giant Planets, Brown Dwarfs, and Low-Mass Dwarf
  Stars II. Sulfur and Phosphorus

abstract:
  Thermochemical equilibrium and kinetic calculations are used to model sulfur
and phosphorus chemistry in giant planets, brown dwarfs, and extrasolar giant
planets (EGPs). The chemical behavior of individual S- and P-bearing gases and
condensates is determined as a function of pressure, temperature, and
metallicity. The results are independent of particular model atmospheres and,
in principle, the equilibrium composition along the pressure-temperature
profile of any object can be determined. Hydrogen sulfide (H2S) is the dominant
S-bearing gas throughout substellar atmospheres and approximately represents
the atmospheric sulfur inventory. Silicon sulfide (SiS) is a potential tracer
of weather in substellar atmospheres. Disequilibrium abundances of phosphine
(PH3) approximately representative of the total atmospheric phosphorus
inventory are expected to be mixed upward into the observable atmospheres of
giant planets and T dwarfs. In hotter objects, several P-bearing gases (e.g.,
P2, PH3, PH2, PH, HCP) become increasingly important at high temperatures.


title:
Observations of Binary and Single Wolf-Rayet Stars with XMM-Newton and
  Chandra

abstract:
  We present an overview of recent X-ray observations of Wolf-Rayet (WR) stars
with XMM-Newton and Chandra. A new XMM spectrum of the nearby WN8 + OB binary
WR 147 shows hard absorbed X-ray emission, including the Fe K-alpha line
complex, characteristic of colliding wind shock sources. In contrast, sensitive
observations of four of the closest known single WC (carbon-rich) WR stars have
yielded only non-detections. These results tentatively suggest that single WC
stars are X-ray quiet. The presence of a companion may thus be an essential
factor in elevating the X-ray emission of WC + OB stars to detectable levels.


title: GOYA Survey: U and B Number Counts in the Groth-Westphal Strip

abstract:
  We present U and B galaxy differential number counts from a field of ~900
arcmin^2, based on GOYA Survey imaging of the HST Groth-Westphal strip. Source
detection efficiency corrections as a function of the object size have been
applied. A variation of the half-exposure image method has been devised to
identify and remove spurious detections. Achieved 50% detection efficiencies
are 24.8 mag in U and 25.5 mag in B in the Vega system. Number count slopes are
d log (N)/dm = 0.50 +/- 0.02 for B=21.0-24.5, and d log (N)/dm = 0.48 +/- 0.03
for U=21.0-24.0. Simple number count models are presented that simultaneously
reproduce the counts over 15 mag in U and B,and over 10 mag in K_s, using a
Lambda-dominated cosmology and SDSS local luminosity functions. Only by setting
a recent z_f ~ 1.5 formation redshift for early-type, red galaxies do the
models reproduce the change of slope observed at Ks = 17.5 in NIR counts. A
moderate optical depth (tau_B = 0.6) for all galaxy types ensures that the
recent formation for ellipticals does not leave a signature in the U or B
number counts, which are featureless at intermediate magnitudes. No ad-hoc
disappearing populations are needed to explain the counts if number evolution
is introduced using an observationally-based z-evolution of the merger
fraction.


title:
Next generation of IACT arrays: scientific objectives versus energy
  domains

abstract:
  Several key motivations and perspectives of ground based gamma-ray astronomy
are discussed in the context of the specifics of detection techniques and
scientific topics/objectives relevant to four major energy domains -- very-low
or \textit{multi-GeV} ($E \leq$ 30 GeV), low or \textit{sub-TeV} (30 GeV - 300
GeV), high or \textit{TeV} (300 GeV - 30 TeV), and very-high or
\textit{sub-PeV} ($E \geq$ 30 TeV) intervals -- to be covered by the next
generation of IACT arrays.


title:
Constraints on the Physics of Type Ia Supernovae from the X-Ray Spectrum
  of the Tycho Supernova Remnant

abstract:
  In this paper we use high quality X-ray observations from XMM-Newton and
Chandra to gain new insights into the explosion that originated Tycho's
supernova 433 years ago. We perform a detailed comparison between the ejecta
emission from the spatially integrated X-ray spectrum of the supernova remnant
and current models for Type Ia supernova explosions. We use a grid of synthetic
X-ray spectra based on hydrodynamic models of the evolution of the supernova
remnant and self-consistent nonequilibrium ionization calculations for the
state of the shocked plasma. We find that the fundamental properties of the
X-ray emission in Tycho are well reproduced by a one-dimensional delayed
detonation model with a kinetic energy of 1.2e51 erg. All the other paradigms
for Type Ia explosions that we have tested fail to provide a good approximation
to the observed ejecta emission, including one-dimensional deflagrations,
pulsating delayed detonations and sub-Chandrasekhar explosions, as well as
deflagration models calculated in three dimensions. Our results require that
the supernova ejecta retain some degree of chemical stratification, with
Fe-peak elements interior to intermediate mass elements. This strongly suggests
that a supersonic burning front (i.e., a detonation) must be involved at some
stage in the physics of Type Ia supernova explosions.


title: Redshift space 21 cm power spectra from reionization

abstract:
  We construct a simple but self-consistent analytic ionization model for rapid
exploration of 21cm power spectrum observables in redshift space. It is fully
described by the average ionization fraction $x_e(z)$ and HII patch size $R(z)$
and has the flexibility to accommodate various reionization scenarios. The
model associates ionization regions with dark matter halos of the number
density required to recover $x_e$ and treats redshift space distortions
self-consistently with the virial velocity of such halos. Based on this model,
we study the line-of-sight structures in the brightness fluctuations since they
are the most immune to foreground contamination. We explore the degeneracy
between the HII patch size and nonlinear redshift space distortion in the one
dimensional power spectrum. We also discuss the limitations experimental
frequency and angular resolutions place on their distinguishability. Angular
resolution dilutes even the radial signal and will be a serious limitation for
resolving small bubbles before the end of reionization. Nonlinear redshift
space distortions suggest that a resolution of order 1 -- 10\arcsec and a
frequency resolution of 10kHz will ultimately be desirable to extract the full
information in the radial field at $z\sim 10$. First generation instruments
such as LOFAR and MWA can potentially measure radial HII patches of a few
comoving Mpc and larger at the end of reionization and are unlikely to be
affected by nonlinear redshift space distortions.


title:
Magnetized hypermassive neutron star collapse: a central engine for
  short gamma-ray bursts

abstract:
  A hypermassive neutron star (HMNS) is a possible transient formed after the
merger of a neutron star binary. In the latest magnetohydrodynamic simulations
in full general relativity, we find that a magnetized HMNS undergoes `delayed'
collapse to a rotating black hole (BH) as a result of angular momentum
transport via magnetic braking and the magnetorotational instability. The
outcome is a BH surrounded by a massive, hot torus with a collimated magnetic
field. The torus accretes onto the BH at a quasi-steady accretion rate ~10
solar mass/s; the lifetime of the torus is ~10 ms. The torus has a temperature
\sim 10^{12} K, leading to copious neutrino-antineutrino thermal radiation.
Therefore, the collapse of an HMNS is a promising scenario for generating
short-duration gamma-ray bursts and an accompanying burst of gravitational
waves and neutrinos.


title:
A general relativistic argument for dark matter existence without
  invoking non-Keplerian rotation curves and gravitational-lensing data

abstract:
  This paper has been withdrawn by the authors because the ratio presented in
Eq. (13) does not remain frozen in time for all values of w = p/rho. As such a
separate more detailed analysis containing the generalized Buchdahl inequality
valid for all values of w is required. The new analysis will in addition attend
to the time evolution of the ratio (13). The essential results remain
unchanged, but result from the w=0 case.


title:
Abundances in red giant stars of NGC 2808 and correlations between
  chemical anomalies and global parameters in globular clusters

abstract:
  We present the abundance analysis of stars from the tip of the red giant
branch (RGB) to below the RGB-bump in the globular cluster NGC 2808, based on
high resolution echelle spectra. We derived abundances of Al, alpha-process
elements (Si I, Ca I, Ti I and Ti II) and Fe-group elements (Sc II, V I, Cr I,
Cr II, Mn I, Co I, Ni I). Apart from Mg being somewhat reduced, likely because
it has been depleted at the expense of Al in the MgAl cycle, the other
alpha-element ratios show the overabundance typical of halo stars of similar
metallicity. Mn is underabundant, whereas Fe-group elements have typical
abundance ratios near the solar value. We detect star-to-star differences in Al
abundances from the RGB tip down to the faintest star below the RGB-bump,
correlated with Na abundances at all luminosities. The slope of the Na-Al
correlation is similar to the one found in M 13 by Sneden et al. (2004), but it
is different from those in other globular clusters of similar metallicity. We
find that the amount of chemical inhomogeneities along the Na-O and Mg-Al
anticorrelations in globular cluster red giants is correlated with the present
day cluster mass and ellipticity. Moreover, we find for the first time a
correlation between the spread in proton-capture elements and orbital
parameters of clusters. The chemical anomalies are more extended in clusters
having large-sized orbits and longer periods, and in clusters with larger
inclination angles of the orbit with respect to the Galactic plane.


title: X-ray Emission from the 3C 273 Jet

abstract:
  We present results from four recent Chandra monitoring observations of the
jet in 3C 273 using the ACIS detector, obtained between November 2003 and July
2004. We find that the X-ray emission comes in two components: unresolved knots
that are smaller than the corresponding optically emitting knots and a broad
channel that is about the same width as the optical interknot region. We
compute the jet speed under the assumption that the X-ray emission is due to
inverse Compton scattering of the cosmic microwave background, finding that the
dimming of the jet X-ray emission to the jet termination relative to the radio
emission may be due to bulk deceleration.


title: On the generation of density perturbations at the end of inflation

abstract:
  Recently a mechanism was proposed whereby the primordial density
perturbations are generated at the end of inflation. We continue the analysis
of the proposed model of this mechanism and calculate the maximum extent to
which the density perturbations produced via this model can dominate over those
of the standard inflationary paradigm. In addition, we provide a
straightforward variation of this model which allows for greater amplification
of the density perturbations. Finally, we show that a variation in the
implementation of the original model results in significant non-gaussianities
in the resulting spectrum of density perturbations. The level of
non-gaussianities can be made to saturate the current observational bound.


title: Dust Production in the High-Redshift Universe

abstract:
  How much dust can be produced in the early Universe? Does dust production
depend on the average heavy-metal content of the hosting galaxy? Considering
supernova explosions, massive stars (Wolf-Rayet, LBV and RSG), and relatively
massive AGB stars among possible dust-generating objects in the early Universe,
we find that SN remnants can be regarded as the main source of the primordial
dust. However, this conclusion is based on highly uncertain (and probably
over-estimated) dust production rates. Despite all the uncertainties,
interstellar extinction must be taken into account while observing
high-redshift objects.


title:
Scattering polarization of hydrogen lines in the presence of turbulent
  electric fields

abstract:
  We study the broadband polarization of hydrogen lines produced by scattering
of radiation, in the presence of isotropic electric fields. In this paper, we
focus on two distinct problems: a) the possibility of detecting the presence of
turbulent electric fields by polarimetric methods, and b) the influence of such
fields on the polarization due to a macroscopic, deterministic magnetic field.
We found that isotropic electric fields decrease the degree of linear
polarization in the scattered radiation, with respect to the zero-field case.
On the other hand, a distribution of isotropic electric fields superimposed
onto a deterministic magnetic field can generate a significant increase of the
degree of magnetic-induced, net circular polarization. This phenomenon has
important implications for the diagnostics of magnetic fields in plasmas using
hydrogen lines, because of the ubiquitous presence of the Holtsmark,
microscopic electric field from neighbouring ions. In particular, previous
solar magnetographic studies of the Balmer lines of hydrogen may need to be
revised because they neglected the effect of turbulent electric fields on the
polarization signals. In this work, we give explicit results for the
Lyman-alpha and Balmer-alpha lines.


title:
Attenuation of VHE gamma rays by the Milky Way interstellar radiation
  field

abstract:
  The attenuation of very high energy gamma rays by pair production on the
Galactic interstellar radiation field has long been thought of as negligible.
However, a new calculation of the interstellar radiation field consistent with
multi-wavelength observations by DIRBE and FIRAS indicates that the energy
density of the Galactic interstellar radiation field is higher, particularly in
the Galactic center, than previously thought. We have made a calculation of the
attenuation of very high energy gamma rays in the Galaxy using this new
interstellar radiation field which takes into account its nonuniform spatial
and angular distributions. We find that the maximum attenuation occurs around
100 TeV at the level of about 25% for sources located at the Galactic center,
and is important for both Galactic and extragalactic sources.


title: Internal Structure of Massive Terrestrial Planets

abstract:
  Planetary formation models predict the existence of massive terrestrial
planets and experiments are now being designed that should succeed in
discovering them and measuring their masses and radii. We calculate internal
structures of planets with one to ten times the mass of the Earth
(Super-Earths) in order to obtain scaling laws for total radius, mantle
thickness, core size and average density as a function of mass. We explore
different compositions and obtain a scaling law of $R\propto M^{0.267-0.272}$
for Super-Earths. We also study a second family of planets, Super-Mercuries
with masses ranging from one mercury-mass to ten mercury-masses with similar
composition to the Earth's but larger core mass fraction. We explore the effect
of surface temperature and core mass fraction on the scaling laws for these
planets. The scaling law obtained for the Super-Mercuries is $R\propto
M^{\sim0.3}$.


title: Heating Cooling Flows with Weak Shock Waves

abstract:
  The discovery of extended, approximately spherical weak shock waves in the
hot intercluster gas in Perseus and Virgo has precipitated the notion that
these waves may be the primary heating process that explains why so little gas
cools to low temperatures. This type of heating has received additional support
from recent gasdynamical models. We show here that outward propagating,
dissipating waves deposit most of their energy near the center of the cluster
atmosphere. Consequently, if the gas is heated by (intermittent) weak shocks
for several Gyrs, the gas within 30-50 kpc is heated to temperatures that far
exceed observed values. This heating can be avoided if dissipating shocks are
sufficiently infrequent or weak so as not to be the primary source of global
heating. Local PV and viscous heating associated with newly formed X-ray
cavities are likely to be small, which is consistent with the low gas
temperatures generally observed near the centers of groups and clusters where
the cavities are located.


title: Baryonically Closed Galaxy Groups

abstract:
  Elliptical galaxies and their groups having the largest L_x/L_B lie close to
the locus in the L_x,L_B diagram expected for closed systems with baryon
fractions equal to the cosmic mean value, f_b = 0.16. The estimated baryon
fractions for several of these galaxies/groups are also close to 0.16 when the
gas density is extrapolated to the virial radius. Evidently they are the least
massive baryonically closed systems. Gas retention in these groups implies that
non-gravitational heating cannot exceed about 1 keV per particle, consistent
with the heating required to produce the deviation of groups from the L_x - T
correlation for more massive clusters. Isolated galaxies/groups with X-ray
luminosities significantly lower than baryonically closed groups may have
undermassive dark halos, overactive central AGNs, or higher star formation
efficiencies. The virial mass and hot gas temperatures of nearly or completely
closed groups correlate with the group X-ray luminosities and the optical
luminosities of the group-centered elliptical galaxy, an expected consequence
of their merging history. The ratio of halo mass to the mass of the central
galaxy for X-ray luminous galaxy/groups is about 80.


title:
Impact of Varying Atmospheric Profiles on Extensive Air Shower
  Observation: Fluorescence Light Emission and Energy Reconstruction

abstract:
  Several experiments measure the fluorescence light produced by extensive air
showers in the atmosphere. This light is converted into a longitudinal shower
profile from which information on the primary energy and composition is
derived. The fluorescence yield, as the conversion factor between light profile
measured by EAS experiments and physical interpretation of showers, has been
measured in several laboratory experiments. The results, however, differ
considerably. In this article, a model calculation of the fluorescence emission
from relevant band systems of nitrogen in dependence on wavelength and
atmospheric conditions is presented. Different calculations are compared to
each other in combination with varying input parameters. The predictions are
compared with measurements and the altitude-dependence of the fluorescence
yield is discussed in detail.


title:
The optical flare and afterglow light curve of GRB 050904 at redshift
  z=6.29

abstract:
  GRB050904 is very interesting since it is by far the most distant GRB event
known to date($z=6.29$). It was reported that during the prompt high energy
emission phase, a very bright optical flare was detected, and it was temporal
coincident with an X-ray flare. Here we use two models to explain the optical
flare, One is the "late internal shock model", in which the optical flare is
produced by the synchrotron radiation of the electrons accelerated by the late
internal shock, and the X-ray flare is produced by the synchrotron-self-Compton
mechanism. The other is the external forward-reverse shock model, in which the
optical flare is from the reverse shock emission and the X-ray flare is
attributed to the central engine activity. We show that with proper parameters,
a bright optical flare can appear in both models. We think the "late internal
shock model" is more favored since in this model the optical flash and the
X-ray flare have the same origin, which provides a natural explanation of the
temporal coincidence of them. In the forward-reverse shock scenario, fits to
the optical flare and the late afterglow suggests that the physical parameters
of the reverse shock are much different from that of forward shock, as found in
modeling the optical flash of GRB 990123 previously.


title: Bar-Halo Friction in Galaxies II: Metastability

abstract:
  It is well-established that strong bars rotating in dense halos generally
slow down as they lose angular momentum to the halo through dynamical friction.
Angular momentum exchanges between the bar and halo particles take place at
resonances. While some particles gain and others lose, friction arises when
there is an excess of gainers over losers. This imbalance results from the
generally decreasing numbers of particles with increasing angular momentum, and
friction can therefore be avoided if there is no gradient in the density of
particles across the major resonances. Here we show that anomalously weak
friction can occur for this reason if the pattern speed of the bar fluctuates
upwards. After such an event, the density of resonant halo particles has a
local inflexion created by the earlier exchanges, and bar slowdown can be
delayed for a long period; we describe this as a metastable state. We show that
this behavior in purely collisionless N-body simulations is far more likely to
occur in methods with adaptive resolution. We also show that the phenomenon
could arise in nature, since bar-driven gas inflow could easily raise the bar
pattern speed enough to reach the metastable state. Finally, we demonstrate
that mild external, or internal, perturbations quickly restore the usual
frictional drag, and it is unlikely therefore that a strong bar in a galaxy
having a dense halo could rotate for a long period without friction.


title:
Radio-far-infrared Correlation and Cosmic Ray Electrons in Starburst
  Galaxies and Ultra Luminous Infrared Galaxies

abstract:
  The ubiquitous and tight correlation between the radio continuum emission and
the far-infrared emission is also found to hold true for starburst galaxies and
Ultra Luminous Infrared Galaxies wherein most of the emission is from compact
structures. The infrared photon density in the cores is high enough for the
inverse Compton scattering to dominate over the synchrotron emission thus
spoiling the correlation. The high magnetic field postulated to avoid this,
also encounters the problem of steep radio index that is not observed. Further,
at high densities the flux of secondary electrons can exceed that of the
primary. The problems posed by such effects are discussed and suggestion for
further work made.


title: AGNs and Starbursts: What Is the Real Connection?

abstract:
  It is now widely believed that the growth of massive black holes is closely
linked to the formation of galaxies, but there have been few concrete
constraints on the actual physical processes responsible for this coupling.
Investigating the connection between AGN and starburst activity may offer some
empirical guidance on this problem. I summarize previous observational searches
for young stars in active galaxies, concluding that there is now compelling
evidence for a significant post-starburst population in many luminous AGNs, and
that a direct, causal link may exist between star formation and black hole
accretion. Quantifying the ongoing star formation rate in AGNs, however, is
much more challenging because of the strong contamination by the active
nucleus. I discuss recent work attempting to measure the star formation rate in
luminous AGNs and quasars. The exceptionally low level of coeval star formation
found in these otherwise gas-rich systems suggests that the star formation
efficiency in the host galaxies is suppressed in the presence of strong AGN
feedback.


title: The colours of the Sun

abstract:
  We compile a sample of Sun-like stars with accurate effective temperatures,
metallicities and colours (from the UV to the near-IR). A crucial improvement
is that the effective temperature scale of the stars has recently been
established as both accurate and precise through direct measurement of angular
diameters obtained with stellar interferometers. We fit the colours as a
function of effective temperature and metallicity, and derive colour estimates
for the Sun in the Johnson/Cousins, Tycho, Stromgren, 2MASS and SDSS
photometric systems. For (B-V)_Sun, we favour the ``red'' colour 0.64 versus
the ``blue'' colour 0.62 of other recent papers, but both values are consistent
within the errors; we ascribe the difference to the selection of Sun-like stars
versus interpolation of wider colour-Teff-metallicity relations.


title:
Emission Measure Distribution and Abundances Measurements During High-T
  Flares

abstract:
  The RSCVn system Sigma Geminorum was observed by XMM-Newton on April 2001
during a large flare. We model the emission measure distribution (EMD) during
the flare and during a quiescence period. In the flare, a two phase behaviour
is found in which the cool plasma (kT < 2 keV) is not disturbed while a large
hot component, at temperatues of kT > 3 keV emerges. Fundamental limitations on
EMD modeling of high temperature plasmas are then discussed, in the context of
the Sigma Gem flare.


title: An Observational Test of Holographic Inflation

abstract:
  Observational consequences of inflationary cosmology in the holographic dual
of the Randall-Sundrum type II braneworld scenario, as motivated by the AdS/CFT
correspondence, are investigated. High energy corrections to the standard
four-dimensional Friedmann equation induce a corresponding modification to the
form of the single-field inflationary consistency equation based on Einstein
gravity. The degree of departure from the standard expression is determined by
the ratio, r, of the primordial tensor and scalar perturbation amplitudes and
the coefficient, c, of the conformal anomaly in the dual gauge theory. It is
found that a necessary condition for detecting such a correction with the next
generation of cosmic microwave background (CMB) polarization experiments is
that r >= 0.06. The bound is tightened to r > 0.3 for values of the central
charge that are compatible with known compactifications of type IIB string
theory as parametrized in terms of F-theory compactification on Calabi-Yau
four-folds. This is close to the present upper bounds inferred from combined
observations of the CMB anisotropy power spectrum and high redshift surveys. We
conclude that if such modifications to the inflationary consistency equation
are to be observable, the gravitational wave background should be detected in
the near future. A further consequence of the non-standard dynamics at high
energies is that the initial state of the universe is a quiescent singularity
with a finite density and pressure.