title: Sulfur Volcanism on Io

abstract:
  In February 2003, March 2003 and January 2004 Pele plume transmission spectra
were obtained during Jupiter transit with Hubble's Space Telescope Imaging
Spectrograph (STIS), using the 0.1 arcsec long slit and the G230LB grating. The
STIS spectra covered the 2100-3100 A wavelength region and extended spatially
along Io's limb both northward of Pele. The S2 and SO2 absorption signatures
evident in the these data indicate that the gas signature at Pele was
temporally variable, and that an S2 absorption signature was present ~ 12 deg.
from the Pele vent near 6+/-5 S and 264 +/-15 W, suggesting the presence of
another S2 bearing plume on Io. Contemporaneous with the spectral data, UV and
visible-wavelength images of the plume were obtained in reflected sunlight with
the Advanced Camera for Surveys (ACS) prior to Jupiter transit. The dust
scattering recorded in these data provide an additional qualitative measure of
plume activity on Io, indicating that the degree of dust scattering over Pele
varied as a function of the date of observation, and that there were several
other dust bearing plumes active just prior to Jupiter transit. We present
constraints on the composition and variability of the gas abundances of the
Pele plume as well as the plumes detected by ACS and recorded within the STIS
data, as a function of time. We discuss the implications of these results for
thermochemical conditions at the plume vents, and our understanding of plume
eruption styles active on Io.


title:
High Mass Star Formation. II. The Mass Function of Submillimeter Clumps
  in M17

abstract:
  We have mapped an approximately 5.5 by 5.5 pc portion of the M17 massive
star-forming region in both 850 and 450 micron dust continuum emission using
the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk
Maxwell Telescope (JCMT). The maps reveal more than 100 dusty clumps with
deconvolved linear sizes of 0.05--0.2 pc and masses of 0.8--120 solar masses,
most of which are not associated with known mid-infrared point sources. Fitting
the clump mass function with a double power law gives a mean power law exponent
of alpha_high = -2.4 +/- 0.3 for the high-mass power law, consistent with the
exponent of the Salpeter stellar mass function. We show that a lognormal clump
mass distribution with a peak at about 4 solar masses produces as good a fit to
the clump mass function as does a double power law. This 4 solar mass peak mass
is well above the peak masses of both the stellar initial mass function and the
mass function of clumps in low-mass star-forming regions. Despite the
difference in intrinsic mass scale, the shape of the M17 clump mass function
appears to be consistent with the shape of the core mass function in low-mass
star-forming regions. Thus, we suggest that the clump mass function in
high-mass star-forming regions may be a scaled-up version of that in low-mass
regions, instead of its extension to higher masses.


title: The Disk and Extraplanar Environment of NGC 247

abstract:
  The stellar content of the spiral galaxy NGC 247 is investigated. The main
sequence turn-off (MSTO) in the inner 12 kpc of the disk corresponds to an age
of 6 Myr. A mean star formation rate (SFR) of 0.1 solar masses per year during
the past 16 Myr is computed from star counts. The color of the red supergiant
plume does not change with radius, suggesting that the mean metallicity of
young stars does not vary by more than 0.1 dex. The number of bright main
sequence stars per local stellar mass density climbs towards larger radii out
to a distance of 12 kpc; the scale lengths that characterize the radial
distributions of young and old stars in the disk thus differ. The density of
bright main sequence stars with respect to projected HI mass gradually drops
with increasing radius. The population of very young stars disappears in the
outer disk; the MSTO at galactocentric radii between 12 and 15 kpc corresponds
to 16 Myr, while between 15 and 18 kpc the age is > 40 Myr. Red giant branch
(RGB) stars are resolved at a projected minor axis galactocentric distance of
12 kpc. There is a broad spread in metallicity among the RGB stars, with a mean
[M/H] = -1.2. The RGB-tip occurs at i' = 24.5 +/- 0.1, indicating that the
distance modulus is 27.9 +/- 0.1. Luminous AGB stars with an age 3 Gyr are also
seen in this field.


title:
VLT/UVES Observations of Interstellar Molecules and Diffuse Bands in the
  Magellanic Clouds

abstract:
  We discuss the abundances of interstellar CH, CH+, and CN in the Magellanic
Clouds (MC), derived from spectra of 7 SMC and 13 LMC stars obtained (mostly)
with the VLT/UVES. CH and/or CH+ are detected toward 3 SMC and 9 LMC stars; CN
is detected toward 2 stars. In the MC, the CH/H2 ratio is comparable to that
found for diffuse Galactic molecular clouds in some sight lines, but is lower
by factors up to 10-15 in others. The abundance of CH in the MC thus appears to
depend on local physical conditions -- and not just on metallicity. The
observed relationships between the column density of CH and those of CN, CH+,
Na I, and K I in the MC are generally consistent with the trends observed in
our Galaxy. Using existing data for the rotational populations of H2, we
estimate temperatures, radiation field strengths, and local hydrogen densities
for the diffuse molecular gas. Densities estimated from N(CH), assuming that CH
is produced via steady-state gas-phase reactions, are considerably higher; much
better agreement is found by assuming that the CH is made via the (still
undetermined) process(es) responsible for the observed CH+. The UVES spectra
also reveal absorption from the diffuse interstellar bands at 5780, 5797, and
6284 A in the MC. On average, the three DIBs are weaker by factors of 7-9 (LMC)
and about 20 (SMC), compared to those observed in Galactic sight lines with
similar N(H I), and by factors of order 2-6, relative to E(B-V), N(Na I), and
N(K I). The detection of several of the ``C2 DIBs'', with strengths similar to
those in comparable Galactic sight lines, however, indicates that no single,
uniform scaling factor (e.g., one related to metallicity) applies to all DIBs
(or all sight lines) in the MC. (abstract abridged)


title:
Properties of High Redshift Quasars-II: What does the quasar luminosity
  function tell us about super-massive black-hole evolution?

abstract:
  In the local universe, the masses of Super-Massive Black-Holes (SMBH) appear
to correlate with the physical properties of their hosts, including the mass of
the dark-matter halo. Using these clues as a starting point many studies have
produced models that can explain phenomena like the quasar luminosity function.
The shortcoming of this approach is that working models are not unique, and as
a result it is not always clear what input physics is being constrained. Here
we take a different approach. We identify critical parameters that describe the
evolution of SMBHs at high redshift, and constrain their parameter space based
on observations of high redshift quasars from the Sloan Digital Sky Survey. We
find that the luminosity function taken in isolation is somewhat limited in its
ability to constrain SMBH evolution due to some strong degeneracies. This
explains the presence in the literature of a range of equally successful models
based on different physical hypotheses. Including the constraint of the local
SMBH to halo mass ratio breaks some of the degeneracies, and our results
suggest halo masses at z~4.8 of 10^{12.5+/-0.3}M_solar (with 90% confidence),
with a SMBH to halo mass ratio that decreases with time (>99%). We also find a
quasar luminosity to halo mass ratio that increases with halo mass (>99%).
These features need to be incorporated in all successful models of SMBH
evolution. On the other hand current observations do not permit any conclusions
regarding the evolution of quasar lifetime, or the SMBH occupation fraction in
dark matter halos.


title:
Primordial Helium Abundance: A Reanalysis of the Izotov-Thuan
  Spectroscopic Sample

abstract:
  A reanalysis is made for the helium abundance determination for the
Izotov-Thuan (2004) spectroscopic sample of extragalactic H II regions. We find
that the effect of underlying stellar absorption of the He I lines, which is
more important for metal poor systems, affects significantly the inferred
primordial helium abundance $Y_p$ obtained in the zero metallicity limit and
the slope of linear extrapolation, $dY/dZ$. This brings $Y_p$ from
$0.234\pm0.004$ to $0.250\pm 0.004$ and $dY/dZ=4.7\pm 1.0$ to $1.1\pm 1.4$.
Conservatively, this indicates the importance of the proper understanding of
underlying stellar absorption for accurate determinations of the primordial
helium abundance to the error of $\delta Y_p\simeq 0.002-0.004$.


title: High eccentricity planets from the Anglo-Australian Planet Search

abstract:
  We report Doppler measurements of the stars HD187085 and HD20782 which
indicate two high eccentricity low-mass companions to the stars. We find
HD187085 has a Jupiter-mass companion with a ~1000d orbit. Our formal `best
fit' solution suggests an eccentricity of 0.47, however, it does not sample the
periastron passage of the companion and we find that orbital solutions with
eccentricities between 0.1 and 0.8 give only slightly poorer fits (based on RMS
and chi^2) and are thus plausible. Observations made during periastron passage
in 2007 June should allow for the reliable determination of the orbital
eccentricity for the companion to HD187085. Our dataset for HD20782 does sample
periastron and so the orbit for its companion can be more reliably determined.
We find the companion to HD20782 has M sin i=1.77+/-0.22M_JUP, an orbital
period of 595.86+/-0.03d and an orbit with an eccentricity of 0.92+/-0.03. The
detection of such high-eccentricity (and relatively low velocity amplitude)
exoplanets appears to be facilitated by the long-term precision of the
Anglo-Australian Planet Search. Looking at exoplanet detections as a whole, we
find that those with higher eccentricity seem to have relatively higher
velocity amplitudes indicating higher mass planets and/or an observational bias
against the detection of high eccentricity systems.


title: A postmortem investigation of the Type IIb supernova 2001ig

abstract:
  We present images taken with the GMOS instrument on Gemini-South, in
excellent (<0.5 arcsec) seeing, of SN 2001ig in NGC 7424, ~1000 days after
explosion. A point source seen at the site of the SN is shown to have colours
inconsistent with being an H II region or a SN 1993J-like remnant, but can be
matched to a late-B through late-F supergiant with A_V<1. We believe this
object is the massive binary companion responsible for periodic modulation in
mass loss material around the Wolf-Rayet progenitor which gave rise to
significant structure in the SN radio light curve.


title:
A Dust Emission Model for Very Young Galaxies: Expected Properties and
  Far Infrared Diagnostics

abstract:
  Dust plays crucial roles in galaxy formation and evolution. In the early
epoch of galaxy evolution dust is only supplied by supernovae (SNe). With the
aid of a new physical model of dust production by SNe, we constructed a model
of dust emission from forming galaxies. We show the evolution of the spectral
energy distribution (SED). Then we adopt this model to a local starbursting
dwarf galaxy SBS 0335$-$052. Further we discuss the SEDs of high redshift
galaxies, and consider their observational feasibility.


title:
Investigating on the nuclear obscuration in two types of Seyfert 2
  galaxies

abstract:
  We build a large sample of Seyfert 2 galaxies (Sy2s) with both optical
spectropolarimetric and X-ray data available, in which 29 Sy2s with the
detection of polarized broad emission line (PBL) and 25 without. We find that
for luminous Sy2s with L_[OIII] > 10^41 erg/s, sources with PBL have smaller
X-ray absorption column density comparing with those without PBL (at 92.3%
confidence level): most of the Sy2s with N_H<10^23.8 cm^-2 show PBL (86%, 12
out 14), while the fraction is much smaller for sources with heavier
obscuration (54%, 15 out 28). The confidence level of the difference in
absorption bounces up to 99.1% while using the "T" ratio (F_2-10keV/F_[O III])
as an indicator. We rule out observation or selection bias as the origin for
the difference. Our results, for the first time with high statistical
confidence, show that, in additional to the nuclei activity, the nuclear
obscuration also plays an important role in the visibility of PBL in Sy2s.
These results can be interpreted in the framework of the unified model. We can
reach these results in the unified model if: a) the absorption column density
is higher at large inclinations and b) the scattering region is obscured at
large inclinations.


title: On the X-ray Baldwin effect for narrow Fe Kalpha emission line

abstract:
  Most Active Galactic Nuclei (AGN) exhibit a narrow Fe Kalpha line at ~ 6.4
keV in the X-ray spectra, due to the fluorescent emission from cold material
far from the inner accretion disk. Using XMM-Newton observations, Page et al.
found that the equivalent width (EW) of the narrow Fe Kalpha line decreases
with increasing luminosity (EW ~ L^-0.17pm0.08), suggesting a decrease in the
covering factor of the material emitting the line (presumably the torus). By
combining the archival Chandra HETG observations of 34 type 1 AGNs with XMM
observations in literature, we build a much large sample with 101 AGNs. We find
a similar X-ray Baldwin effect in the sample (EW ~ L^-0.2015pm0.0426), however,
we note that the anti-correlation is dominated by the radio loud AGN in the
sample, whose X-ray spectra might be contaminated by the relativistic jet.
Excluding the radio loud AGN, we find a much weaker anti-correlation (EW ~
L^-0.1019pm0.0524). We present Monte-Carlo simulations showing that such a weak
anti-correlation can be attributed to the relative short time scale variations
of the X-ray continuum.


title:
Electron-ion recombination measurements motivated by AGN X-ray
  absorption features: Fe XIV forming Fe XIII

abstract:
  Recent spectroscopic models of active galactic nuclei (AGN) have indicated
that the recommended electron-ion recombination rate coefficients for iron ions
with partially filled M-shells are incorrect in the temperature range where
these ions form in photoionized plasmas. We have investigated this
experimentally for Fe XIV forming Fe XIII. The recombination rate coefficient
was measured employing the electron-ion merged beams method at the Heidelberg
heavy-ion storage-ring TSR. The measured energy range of 0-260 eV encompassed
all dielectronic recombination (DR) 1s2 2s2 2p6 3l 3l' 3l'' nl''' resonances
associated with the 3p1/2 -> 3p3/2, 3s -> 3p, 3p -> 3d and 3s -> 3d core
excitations within the M-shell of the Fe XIV 1s2 2s2 2p6 3s2 3p parent ion.
This range also includes the 1s2 2s2 2p6 3l 3l' 4l'' nl''' resonances
associated with 3s -> 4l'' and 3p -> 4l'' core excitations. We find that in the
temperature range 2--14 eV, where Fe XIV is expected to form in a photoionized
plasma, the Fe XIV recombination rate coefficient is orders of magnitude larger
than previously calculated values.


title: Detectability of dirty dust grains in brown dwarf atmospheres

abstract:
  Dust clouds influence the atmospheric structure of brown dwarfs, and they
affect the heat transfer and change the gas-phase chemistry. However, the
physics of their formation and evolution is not well understood. In this
letter, we predict dust signatures and propose a potential observational test
of the physics of dust formation in brown dwarf atmosphere based on the
spectral features of the different solid components predicted by dust formation
theory. A momentum method for the formation of dirty dust grains (nucleation,
growth, evaporation, drift) is used in application to a static brown dwarf
atmosphere structure to compute the dust grain properties, in particular the
heterogeneous grain composition and the grain size. Effective medium and Mie
theory are used to compute the extinction of these spherical grains. Dust
formation results in grains whose composition differs from that of grains
formed at equilibrium. Our kinetic model predicts that solid amorphous SiO2[s]
  (silica) is one of the most abundant solid component followed by amorphous
  MgSiO4[s] and MgSiO3[s], while SiO2[s] is absent in equilibrium models
because it is a metastable solid. Solid amorphous SiO2[s] possesses a strong
broad absorption feature centered at 8.7mum, while amorphous
Mg2SiO4[s]/MgSiO3[s] absorb at 9.7mum beside other absorption features at
longer wavelength. Those features at lambda < 15mum are detectable in
absorption if grains are small (radius < 0.2mum) in the upper atmosphere as
suggested by our model. We suggest that the detection of a feature at 8.7mum in
deep infrared spectra could provide evidence for non-equilibrium dust formation
that yields grains composed of metastable solids in brown dwarf atmospheres.
This feature will shift towards 10mum and broaden if silicates (e.g. fosterite)
are much more abundant.


title: A hierarchy of cosmic compact objects - without black holes

abstract:
  We make the case for the existence of a, hitherto unknown and unobserved,
hierarchy of ever more compact cosmic objects in the universe. This hypothesis
is based on i) the assumption of "elementary" particle sub-constituents on
several levels below the presently known, inspired by Glashow's "blooming
desert", ii) the existence of nearly scale-invariant density fluctuations in
the early universe, e.g. as predicted by inflationary models, iii) our own
previous theoretical work showing that a class of objects considerably more
compact than previously thought possible in astrophysics can exist. We also
give several independent arguments strongly pointing towards the non-existence
of black holes. Some brief suggestions on observational signals due to the
hierarchy, both in collected astronomical data and in possible future
observations, concludes the paper.


title:
Radiation from an expanding cocoon as an explanation of the steep decay
  observed in GRB early afterglow light curves

abstract:
  Observations of early afterglow emission from gamma-ray bursts (GRB's) with
the Swift satellite show steep decay of the X-ray light curve, F_\nu(t) ~
t^{-\alpha} with \alpha ~ 2.5 - 4 at ~300-500 s after the burst trigger. The
spectrum in this time interval is consistent with a spectrum F_\nu ~
\nu^{-\beta} with \beta ~1. Here, we show that these results can be explained
as due to emission from the hot plasma "cocoon" associated with the jet, which
expands relativistically after the jet has broken through the stellar envelope,
if a substantial fraction of the coccon kinetic energy is dissipated at
scattering optical depths \tau_T ~ 10^2-10^3. This results in the bulk of the
coccon photons being observed at X-ray energies, after a delay of few hundreds
of seconds relative to the gamma-ray photons from the jet. Multiple Compton
scattering inside the cocoon causes a spread in the arrival times of the X-ray
photons. We calculate numerically the observed light curve of photons emerging
from the cocoon, and show that it exhibits a steep decay, which resembles that
observed in many GRB afterglows. During the adiabatic expansion that follows
the dissipation phase, photons lose energy to the expanding plasma, and as a
result, the emerging photon energy distribution differs from a black-body
spectrum, and can be approximated as a power law in the Swift XRT band.
Comparison of the numerical results with the Swift XRT data of GRB050315 and
GRB050421 shows good agreement between the light curves and spectra during the
initial steep decay phase.


title: First Two-Micron Imaging Polarimetry of Beta Pictoris

abstract:
  High-resolution K band imaging polarimetry of the beta Pic dust disk has been
conducted with adaptive optics and a coronagraph using the Subaru 8.2-m
telescope. Polarization of ~10 % is detected out to r ~ 120 AU with a
centro-symmetric vector pattern around the central star, confirming that the
disk is seen as an infrared reflection nebula. We have modeled our
near-infrared and previous optical polarization results in terms of dust
scattering in the disk and have found that both the degrees of polarization and
the radial intensity profiles are well reproduced. We argue that the observed
characteristics of the disk dust are consistent with the presence of ice-filled
fluffy aggregates consisting of submicron grains in the beta Pic system. There
is a gap around 100 AU in both the intensity and polarization profiles, which
suggests a paucity of planetesimals in this region. The radial intensity
profile also shows ripple-like structures, which are indicative of the presence
of multiple planetesimal belts, as in the case of the M-type Vega-like star AU
Mic.


title:
The host galaxy/AGN connection in nearby early-type galaxies. A new view
  of the origin of the radio-quiet/radio-loud dichotomy?

abstract:
  [ABRIDGED] This is the third in a series of three papers exploring the
connection between the multiwavelength properties of AGN in nearby early-type
galaxies and the characteristics of their hosts. We selected 116 AGN candidates
requiring a radio flux of 1 mJy. We classified the objects with HST images into
``core'' and ``power-law'' galaxies, on the basis of the nuclear slope of their
brightness profiles. We used HST and Chandra data to isolate their nuclear
emission to study the multiwavelength behaviour of their nuclei. The properties
of the nuclei hosted by the 29 core galaxies were presented in Paper II. Core
galaxies invariably host a radio-loud nucleus, with a median radio-loudness of
Log R = 3.6 and an X-ray based radio loudness parameter of Log R,X = -1.3. Here
we discuss the properties of the nuclei of the 22 ``power-law'' galaxies. They
show a substantial excess of optical and X-ray emission with respect to core
galaxies at the same level of radio luminosity. Conversely, their
radio-loudness parameters, Log R ~ 1.6 and Log R,X ~ -3.3, are similar to those
measured in Seyfert galaxies. Thus the radio-loudness of AGN hosted by
early-type galaxies appears to be univocally related to the host's brightness
profile: radio-loud AGN are only hosted by core galaxies, while radio-quiet AGN
are found only in power-law galaxies. The brightness profile is determined by
the galaxy's evolution, through its merger history; our results suggest that
the same process sets the AGN flavour.


title: Extrasolar Transiting Planet Search with Subaru Suprime-Cam

abstract:
  We report the results of a prototype photometric search for transiting
extrasolar planets using Subaru Suprime-Cam. Out of about 100,000 stars
monitored around the Galactic plane (l=90 degree,b=0 degree), we find that
7,700 (27,000) stars show the photometric precision below 1% (3%) for 60 second
exposures which is required to detect extrasolar planets by the transit method.
Thus Suprime-Cam has the photometric stability and accuracy required for a
transiting planet survey. During this observing run, we detected three
transiting planetary candidates (i'-band magnitude around 18.5) which exhibit a
single full transit-like light curve with a fractional depth of <5%. While
future photometric and/or spectroscopic follow-ups remain to be done, the
estimated parameters for the three systems are consistent with planetary
companions around main-sequence stars. We also found two eclipsing binary
candidates and eleven variable stars exhibiting W UMa-like light curves.


title: The X-ray properties of the magnetic Cataclysmic Variable UU Col

abstract:
  XMM-Newton observations aimed at determining for the first time the
broad-band X-ray properties of the faint high galactic latitude Intermediate
Polar UU Col are presented. We performed X-ray timing analysis in different
energy ranges of the EPIC cameras which reveals the dominance of the 863s white
dwarf rotational period. The spin pulse is strongly energy dependent. Weak
variabilities at the beat 935s and at the 3.5hr orbital periods are also
observed, but the orbital modulation is detected only below 0.5keV.
Simultaneous UV and optical photometry shows that the spin pulse is anti-phased
with respect to the hard X-rays. Analysis of the EPIC and RGS spectra reveals
the complexity of the X-ray emission, being composed of a soft 50eV black--body
component and two optically thin emission components at 0.2keV and 11keV
strongly absorbed by dense material with an equivalent hydrogen column density
of 10**(23)cm**(-2) partially (50%) covering the X-ray source. The complex
X-ray and UV/optical temporal behaviour indicates that accretion occurs
predominantly (80%) via a disc with a partial contribution (20%) directly from
the stream. The main accreting pole dominates at high energies whilst the
secondary pole mainly contributes in the soft X-rays and at lower energies. The
bolometric flux ratio of the soft-to-hard X-ray emissions is found to be
consistent with the prediction of the standard accretion shock model. We find
the white dwarf in UU Col accretes at a low rate and possesses a low magnetic
moment. It is therefore unlikely that UU Col will evolve into a moderate field
strength Polar, which leaves the soft X-ray Intermediate Polars a still
enigmatic small group of magnetic Cataclysmic Variables.


title: On the mean field dynamo with Hall effect

abstract:
  We study in the present paper how Hall effect modifies the quenching process
of the electromotive force (e.m.f.) in Mean Field Dynamo (MFD) theories. We
write down the evolution equations for the e.m.f. and for the large and small
scale magnetic helicity, treat Hall effect as a perturbation and integrate the
resulting equations assuming boundary conditions such that the total
divergencies vanish. For force-free large scale magnetic fields, Hall effect
acts by coupling the small scale velocity and magnetic fields. For the range of
parameters considered, the overall effect is a stronger quenching of the e.m.f.
than in standard MHD and a damping of the inverse cascade of magnetic helicity.
In astrophysical environments characterized by the parameters considered here,
Hall effect would produce an earlier quenching of the e.m.f. and consequently a
weaker large scale magnetic field.


title: Large-scale study of the NGC 1399 globular cluster system in Fornax

abstract:
  We present a Washington C and Kron-Cousins R photometric study of the
globular cluster system of NGC 1399, the central galaxy of the Fornax cluster.
A large areal coverage of 1 square degree around NGC 1399 is achieved with
three adjoining fields of the MOSAIC II Imager at the CTIO 4-m telescope.
Working on such a large field, we can perform the first indicative
determination of the total size of the NGC 1399 globular cluster system. The
estimated angular extent, measured from the NGC 1399 centre and up to a
limiting radius where the areal density of blue globular clusters falls to 30
per cent of the background level, is 45 +/- 5 arcmin, which corresponds to 220
- 275 kpc at the Fornax distance. The bimodal colour distribution of this
globular cluster system, as well as the different radial distribution of blue
and red clusters, up to these large distances from the parent galaxy, are
confirmed. The azimuthal globular cluster distribution exhibits asymmetries
that might be understood in terms of tidal stripping of globulars from NGC
1387, a nearby galaxy. The good agreement between the areal density profile of
blue clusters and a projected dark-matter NFW density profile is emphasized.


title:
Cold molecular gas in the Perseus cluster core - Association with X-ray
  cavity, Halpha filaments and cooling flow -

abstract:
  Cold molecular gas has been recently detected in several cooling flow
clusters of galaxies where huge optical nebulosities often stand. These optical
filaments are tightly linked to the cooling flow and to the related phenomena,
like the rising bubbles of relativistic plasma, fed by the radio jets. We
present here a map in the CO(2-1) rotational line of the cold molecular gas
associated with some Halpha filaments surrounding the central galaxy of the
Perseus cluster: NGC 1275. The map, extending to about 50 kpc (135 arcsec) from
the center of the galaxy, has been made with the 18-receiver array HERA, at the
focus of the IRAM 30m telescope. Although most of the cold gas is concentrated
to the center of the galaxy, the CO emission is also clearly associated to the
extended filaments conspicuous in ionised gas and could trace a possible
reservoir fueling the star formation there. Some of the CO emission is also
found where the X-ray gas could cool down more efficiently: at the rims of the
central X-ray cavity (where the hot gas is thought to have been pushed out and
compressed by the central AGN expanding radio lobes). The CO global kinematics
does not show any rotation in NGC 1275. The cold gas is probably a mixture of
gas falling down on the central galaxy and of uplifted gas dragged out by a
rising bubble in the intracluster medium. As recenlty suggested in other
cluster cores, the cold gas peculiar morphology and kinematics argue for the
picture of an intermittent cooling flow scenario where the central AGN plays an
important role.


title:
Thermal Stability of White Dwarfs Accreting Hydrogen-rich Matter and
  Progenitors of Type Ia Supernovae

abstract:
  We revisit the properties of white dwarfs accreting hydrogen-rich matter by
constructing steady-state models, in which hydrogen shell burning consumes
hydrogen at the same rate as the white dwarf accretes it. We obtain such
steady-state models for various accretion rates and white dwarf masses. We
confirm that these steady models are thermally stable only when the accretion
rate is higher than \sim 10^{-7} M_sun/yr. We show that recent models of
``quiescent burning'' in the ``surface hydrogen burning'' at a much wider range
of accretion rates results from the too large zone mass in the outer part of
the models; hydrogen burning must occur in a much thinner layer. A comparison
of the positions on the HR diagram suggests that most of the luminous supersoft
X-ray sources are white dwarfs accreting matter at rates high enough that the
hydrogen burning shell is thermally stable. Implications on the progenitors of
Type Ia supernovae are discussed.


title: What can we learn from long term monitoring of X-ray bursters?

abstract:
  The last few years have seen the discovery of a number of new aspects of Type
I X-ray bursts: the extremely energetic and long duration superbursts,
intermediate duration bursts at low luminosities, mHz QPOs, and burst
oscillations. These discoveries promise a new understanding of nuclear burning
on accreting neutron stars, and offer a chance to use observations to probe
neutron star properties. I discuss what we can learn from future long term
monitoring with MIRAX.


title: Observational constraints on self-accelerating cosmology

abstract:
  The DGP brane-world model provides a simple alternative to the standard LCDM
cosmology, with the same number of parameters. There is no dark energy - the
late universe self-accelerates due to an infrared modification of gravity. We
compute the joint constraints on the DGP model from supernovae, the cosmic
microwave background shift parameter, and the baryon oscillation peak in the
SDSS luminous red galaxy sample. Flat DGP models are within the joint 2 sigma
contour, but the LCDM model provides a significantly better fit to the data.
These tests are based on the background dynamics of the DGP model, and we
comment on further tests that involve structure formation.


title:
High-resolution mapping of interstellar clouds with near-infrared
  scattered light

abstract:
  With current wide-field near-infrared (NIR) instruments the scattered light
in the near-infrared can be mapped over large areas. Below A_V ~ 10 the surface
brightness is directly proportional to the column density, and at slightly
higher column densities the saturation of the intensity values can be corrected
using the ratios of the intensity in different NIR bands. NIR scattered light
provides a promising new method for the mapping of quiescent interstellar
clouds. We develop a method to convert the observed near-infrared surface
brightness into estimates of the column density. We study and quantify the
effect that different error sources could have on the accuracy of such
estimates. We also propose to reduce systematic errors by combining surface
brightness data with extinction measurements derived from the near-infrared
colour excess of background stars. Our study is based on a set of
three-dimensional magnetohydrodynamic turbulence simulations. Maps of
near-infrared scattered light are obtained with radiative transfer
calculations, and the maps are converted back into column density estimates
using the proposed method. The results are compared with the true column
densities. Extinction measurements are simulated using the same turbulence
simulations, and are used as a complementary column density tracer. We find
that NIR intensities can be converted into a reliable estimate of the column
density in regions with A_V up to almost 20mag.


title:
Integrated-light VRI imaging photometry of globular clusters in the
  Magellanic clouds

abstract:
  We present accurate integrated-light photometry in Johnson/Cousins V, R, and
I for a sample of 28 globular clusters in the Magellanic Clouds. The majority
of the clusters in our sample have reliable age and metallicity estimates
available in the literature. The sample encompasses ages between 50 Myr and 7
Gyr, and metallicities ([Fe/H]) between -1.5 and 0.0 dex. The sample is
dominated by clusters of ages between roughly 0.5 and 2 Gyr, an age range
during which the bolometric luminosity of simple stellar populations is
dominated by evolved red giant branch stars and thermally pulsing asymptotic
giant branch (TP-AGB) stars whose theoretical colours are rather uncertain. The
VRI colours presented in this paper have been used to calibrate stellar
population synthesis model predictions.


title: HST/FOS Spectral Mapping of V2051 Ophiuchi in a Low State

abstract:
  We report a study of the spectra and structure of the accretion disk of the
dwarf nova V2051 Ophiuchi while the star was in an unusual faint brightness
state during 1996. The differences between the UV resonant lines and continuum
disk surface brightness distributions indicate a vertically extended disk with
the emission from these lines arising from the upper atmospheric layers.
Distinct emission along the stream trajectory suggests the occurrence of gas
stream overflow. Spatially resolved spectra show that the lines are in emission
at all disk radii. The Balmer decrement becomes shallower with increasing
radius. The FWHMs of the emission lines show differences with respect to that
expected for a gas in Keplerian rotation and the line intensities drop with a
radial dependency of $I\propto R^{-1.78}$. The uneclipsed light contributes
about 5 - 10 per cent of the total flux, and its spectrum is dominated by a
Balmer jump and strong lines in emission. Broad absorption bands, possibly due
to Fe II, are present in the spectra of the disk side farther away from the
secondary star, suggesting it arises from absorption by a extended gas region
above the disk; the differences between the spectra of the hemisphere farther
from and nearer to the secondary star are interpreted in terms of chromospheric
emission from a disc with a non-negligible opening angle (limb brightening
effect). Stellar atmosphere model fits to the extracted white dwarf spectrum
lead to a temperature $T_{WD}= 9500 ^{+2900}_{-1900} K$ and a distance of $d =
67 ^{+22}_{-25} pc$ if the inner disk is opaque, or $d = 92 ^{+30}_{-35} pc$ if
the inner disk is optically thin.


title: Molecular Cloud Turbulence and Star Formation

abstract:
  We review the properties of turbulent molecular clouds (MCs), focusing on the
physical processes that influence star formation (SF). MC formation appears to
occur during large-scale compression of the diffuse ISM driven by supernovae,
magnetorotational instability, or gravitational instability in galactic disks
of stars and gas. The compressions generate turbulence that can accelerate
molecule production and produce the observed morphology. We then review the
properties of MC turbulence, including density enhancements observed as clumps
and cores, magnetic field structure, driving scales, the relation to observed
scaling relations, and the interaction with gas thermodynamics. We argue that
MC cores are dynamical, not quasistatic, objects with relatively short
lifetimes not exceeding a few megayears. We review their morphology, magnetic
fields, density and velocity profiles, and virial budget. Next, we discuss how
MC turbulence controls SF. On global scales turbulence prevents monolithic
collapse of the clouds; on small scales it promotes local collapse. We discuss
its effects on the SF efficiency, and critically examine the possible relation
between the clump mass distribution and the initial mass function, and then
turn to the redistribution of angular momentum during collapse and how it
determines the multiplicity of stellar systems. Finally, we discuss the
importance of dynamical interactions between protostars in dense clusters, and
the effect of the ionization and winds from those protostars on the surrounding
cloud. We conclude that the interaction of self-gravity and turbulence controls
MC formation and behavior, as well as the core and star formation processes
within them.


title: The Chemical Evolution of Protoplanetary Disks

abstract:
  In this review we re-evaluate our observational and theoretical understanding
of the chemical evolution of protoplanetary disks. We discuss how improved
observational capabilities have enabled the detection of numerous molecules
exposing an active disk chemistry that appears to be in disequilibrium. We
outline the primary facets of static and dynamical theoretical chemical models.
Such models have demonstrated that the observed disk chemistry arises from warm
surface layers that are irradiated by X-ray and FUV emission from the central
accreting star. Key emphasis is placed on reviewing areas where disk chemistry
and physics are linked: including the deuterium chemistry, gas temperature
structure, disk viscous evolution (mixing), ionization fraction, and the
beginnings of planet formation.


title: Infrared Constraints on AGN Tori Models

abstract:
  This work focuses on the properties of dusty tori in active galactic nuclei
(AGN) derived from the comparison of SDSS type 1 quasars with mid-Infrared
(MIR) counterparts and a new, detailed torus model. The infrared data were
taken by the Spitzer Wide-area InfraRed Extragalactic (SWIRE) Survey. Basic
model parameters are constraint, such as the density law of the graphite and
silicate grains, the torus size and its opening angle. A whole variety of
optical depths is supported. The favoured models are those with decreasing
density with distance from the centre, while there is no clear tendency as to
the covering factor, ie small, medium and large covering factors are almost
equally distributed. Based on the models that better describe the observed
SEDs, properties such as the accretion luminosity, the mass of dust, the inner
to outer radius ratio and the hydrogen column density are computed.


title: First Light

abstract:
  The first dwarf galaxies, which constitute the building blocks of the
collapsed objects we find today in the Universe, had formed hundreds of
millions of years after the big bang. This pedagogical review describes the
early growth of their small-amplitude seed fluctuations from the epoch of
inflation through dark matter decoupling and matter-radiation equality, to the
final collapse and fragmentation of the dark matter on all mass scales above
\~10^{-4} solar masses. The condensation of baryons into halos in the mass
range of ~10^5-10^{10} solar masses led to the formation of the first stars and
the re-ionization of the cold hydrogen gas, left over from the big bang. The
production of heavy elements by the first stars started the metal enrichment
process that eventually led to the formation of rocky planets and life. A wide
variety of instruments currently under design [including large-aperture
infrared telescopes on the ground or in space (JWST), and low-frequency arrays
for the detection of redshifted 21cm radiation], will establish better
understanding of the first sources of light during an epoch in cosmic history
that was largely unexplored so far. Numerical simulations of reionization are
computationally challenging, as they require radiative transfer across large
cosmological volumes as well as sufficently high resolution to identify the
sources of the ionizing radiation. The technological challenges for
observations and the computational challenges for numerical simulations, will
motivate intense work in this field over the coming decade.


title: Identification of the Broad Solar Emission Features Near 117 nm

abstract:
  Wilhelm et al. have recently called attention to the unidentified broad
emission features near 117 nm in the solar spectrum. They discuss the observed
properties of these features in detail but do not identify the source of this
emission.
  We show that the broad autoionizing transitions of neutral sulfur are
responsible for these emission features. Autoionizing lines of \ion{S}{i} occur
throughout the spectrum between Lyman alpha and the Lyman limit. Sulfur is a
normal contributor to stellar spectra.
  We use non-LTE chromospheric model calculations with line data from the
Kurucz 2004 \ion{S}{i} line list to simulate the solar spectrum in the range
116 to 118 nm. We compare the results with SUMER disk-center observations from
Curdt et al. and limb observations from Wilhelm et al.
  Our calculations generally agree with the SUMER observations of the broad
autoionizing \ion{S}{i} emission features, the narrow \ion{S}{i} emission
lines, and the continuum in this wavelength region, and agree with basic
characteristics of the center-to-limb observations. In addition to modeling the
average spectrum, we show that a change of $\pm$ 200 K in the temperature
distribution causes the intensity to change by a factor of 4. This exceeds the
observed intensity variations 1) with time in quiet regions at these
wavelengths, and 2) with position from cell centers to bright network. These
results do not seem compatible with current dynamical models that have temporal
variations of 1000 K or more in the low chromosphere.


title:
Stochastic particle acceleration and synchrotron self--Compton radiation
  in TeV blazars

abstract:
  We analyse the influence of the stochastic particle acceleration for the
evolution of the electron spectrum. We assume that all investigated spectra are
generated inside a spherical, homogeneous source and also analyse the
synchrotron and inverse Compton emission generated by such an object. The
stochastic acceleration is treated as the diffusion of the particle momentum
and is described by the momentum-diffusion equation. We investigate the
stationary and time dependent solutions of the equation for several different
evolutionary scenarios. The scenarios are divided into two general classes.
First, we analyse a few cases without injection or escape of the particles
during the evolution. Then we investigate the scenarios where we assume
continuous injection and simultaneous escape of the particles. In the case of
no injection and escape the acceleration process, competing with the radiative
cooling, only modifies the initial particle spectrum. The competition leads to
a thermal or quasi-thermal distribution of the particle energy. In the case of
the injection and simultaneous escape the resulting spectra depend mostly on
the energy distribution of the injected particles. In the simplest case, where
the particles are injected at the lowest possible energies, the competition
between the acceleration and the escape forms a power-law energy distribution.
We apply our modeling to the high energy activity of the blazar Mrk 501
observed in April 1997. Calculating the evolution of the electron spectrum
self-consistently we can reproduce the observed spectra well with a number of
free parameters that is comparable to or less than in the "classic stationary"
one--zone synchrotron self-Compton scenario.


title:
Cosmic-Ray Acceleration at Ultrarelativistic Shock Waves: Effects of
  Downstream Short-Wave Turbulence

abstract:
  The present paper is the last of a series studying the first-order Fermi
acceleration processes at relativistic shock waves with the method of Monte
Carlo simulations applied to shocks propagating in realistically modeled
turbulent magnetic fields. The model of the background magnetic field structure
of Niemiec & Ostrowski (2004, 2006) has been augmented here by a
large-amplitude short-wave downstream component, imitating that generated by
plasma instabilities at the shock front. Following Niemiec & Ostrowski (2006),
we have considered ultrarelativistic shocks with the mean magnetic field
oriented both oblique and parallel to the shock normal. For both cases
simulations have been performed for different choices of magnetic field
perturbations, represented by various wave power spectra within a wide
wavevector range. The results show that the introduction of the short-wave
component downstream of the shock is not sufficient to produce power-law
particle spectra with the "universal" spectral index 4.2. On the contrary,
concave spectra with cutoffs are preferentially formed, the curvature and
cutoff energy being dependent on the properties of turbulence. Our results
suggest that the electromagnetic emission observed from astrophysical sites
with relativistic jets, e.g. AGN and GRBs, is likely generated by particles
accelerated in processes other than the widely invoked first-order Fermi
mechanism.


title:
X-ray emission from the blazar AO 0235+16: the XMM-Newton and Chandra
  point of view

abstract:
  In this paper we analyse five observations of the BL Lac object AO 0235+16
performed with the Chandra and XMM-Newton satellites during the years
2000-2005. In the February 2002 observation the source is found in a bright
state and presents a steep X-ray spectrum, while in all the other epochs it is
faint and the spectrum is hard. The soft X-ray spectrum appears to be strongly
absorbed, likely by the intervening system at z=0.524, which also absorbs the
optical-UV radiation. We find that models that consider spectral curvature are
superior to single power law ones in fitting the X-ray spectrum. In particular,
we favour a double power law model, which agrees with the assumption of a
superposition of two different components in the X-ray domain. Both in the
Chandra and in one of the XMM-Newton observations, a tentative detection of the
redshifted Fe Kalpha emission line may suggest its origin from the inner part
of an accretion disc. Thermal emission from this accretion disc might explain
the UV-soft-X-ray bump that appears in the spectral energy distributions, when
the X-ray spectra are complemented with the optical-UV data from the Optical
Monitor onboard XMM-Newton. More likely, the bump can be interpreted in terms
of an additional synchrotron component emitted from an inner region of the jet
with respect to that where the lower-energy emission comes from. An inspection
of the X-ray light curves reveals that intraday variability occurs only when
the source is in a bright state.


title: Matched Filters for Source Detection in the Poissonian Noise Regime

abstract:
  A procedure is described for estimating an optimum kernel for the detection
by convolution of signals among Poissonian noise. The technique is applied to
the detection of x-ray point sources in XMM-Newton data, and is shown to yield
an improvement in detection sensitivity of up to 60% over the sliding-box
method used in the creation of the 1XMM catalog.


title: Chaplygin inspired Inflation

abstract:
  We discuss chaotic inflation in the context of a phenomenological
modification of gravity inspired by the Chaplygin gas equation of state. We
find that all observationalconstraints can be satisfied provided the Chaplygin
scale is smaller than $6.9 \times 10^{-3} M$ and the inflaton mass is smaller
than $4.7 \times 10^{-6} M$, respectively, where $M^2\equiv(8 \pi G)^{-1} is
the reduced Planck mass.


title:
Global universe anisotropy probed by the alignment of structures in the
  cosmic microwave background

abstract:
  We question the global universe isotropy by probing the alignment of local
structures in the cosmic microwave background (CMB) radiation. The original
method proposed relies on a steerable wavelet decomposition of the CMB signal
on the sphere. The analysis of the first-year WMAP data identifies a mean
preferred plane with a normal direction close to the CMB dipole axis, and a
mean preferred direction in this plane, very close to the ecliptic poles axis.
Previous statistical anisotropy results are thereby synthesized, but further
analyses are still required to establish their origin.


title:
Restrictions on parameters of sterile neutrino dark matter from
  observations of galaxy clusters

abstract:
  We find restrictions on the mass and mixing angle of the dark matter sterile
neutrinos using X-ray observations of Coma and Virgo galaxy clusters.


title: CMB multipole measurements in the presence of foregrounds

abstract:
  Most analysis of Cosmic Microwave Background spherical harmonic coefficients
a_lm has focused on estimating the power spectrum C_l=<|a_lm|^2> rather than
the coefficients themselves. We present a minimum-variance method for measuring
a_lm given anisotropic noise, incomplete sky coverage and foreground
contamination, and apply it to the WMAP data. Our method is shown to constitute
lossless data compression in the sense that the widely used quadratic
estimators of the power spectrum C_l can be computed directly from our
a_lm-estimators. As the Galactic cut is increased, the error bars Delta-a_lm on
low multipoles go from being dominated by foregrounds to being dominated by
sample variance from other multipoles, with the intervening minimum defining
the optimal cut. Applying our method to the WMAP quadrupole and octopole, we
find that their previously reported "axis of evil" alignment appears to be
rather robust to Galactic cut and foreground contamination.


title:
Weak-line T Tauri Star Disks I. Initial Spitzer Results from the Cores
  to Disks Legacy Project

abstract:
  Using the Spitzer Space Telescope, we have observed 90 weak-line and
classical T Tauri stars in the vicinity of the Ophiuchus, Lupus, Chamaeleon,
and Taurus star-forming regions as part of the Cores to Disks (c2d) Spitzer
Legacy project. In addition to the Spitzer data, we have obtained
contemporaneous optical photometry to assist in constructing spectral energy
distributions. These objects were specifically chosen as solar-type young stars
with low levels of H alpha emission, strong X-ray emission, and lithium
absorption i.e. weak-line T Tauri stars, most of which were undetected in the
mid-to-far IR by the IRAS survey. Weak-line T Tauri stars are potentially
extremely important objects in determining the timescale over which disk
evolution may take place. Our objective is to determine whether these young
stars are diskless or have remnant disks which are below the detection
threshold of previous infrared missions. We find that only 5/83 weak-line T
Tauri stars have detectable excess emission between 3.6 and 70 micron which
would indicate the presence of dust from the inner few tenths of an AU out to
the planet-forming regions a few tens of AU from the star. Of these sources,
two have small excesses at 24 microns consistent with optically thin disks; the
others have optically thick disks already detected by previous IR surveys. All
of the seven classical T Tauri stars show excess emission at 24 and 70 micron,
although their properties vary at the shorter wavelengths. Our initial results
show that disks are rare among young stars selected for their weak H alpha
emission.


title: The Expansion Asymmetry and Age of the Cassiopeia A Supernova Remnant

abstract:
  HST ACS images of the young SN remnant Cas A are used to explore the
expansion and spatial distribution of its highest velocity debris. Proper
motions of over 1800 outlying ejecta knots are reported. The distribution of
transverse expansion velocities for these knots shows a striking bipolar
asymmetry with the highest velocity knots confined to nearly opposing northeast
and southwest `jets'. The jets appear kinematically and chemically distinct
with respect to the remnant's highest velocity debris seen in other directions.
Significant gaps in the spatial distribution of outlying ejecta lie in
directions which are approximately perpendicular to the jets. Extrapolations of
9 month proper motions for all outer ejecta knots and a subsample of 72 bright
and compact knots suggest explosion dates (assuming no knot deceleration) of
1662 +/- 27 and 1672 +/- 18, respectively. We find some evidence for
non-uniform deceleration in different directions with knots located along the
northwestern limb among the least decelerated ejecta suggesting a convergence
date of 1681 +/-19. The remnant's central X-ray point source lies some $7''$ to
the southeast of the estimated expansion center (PA = 169 deg) indicating a
projected motion of ~350 km/s toward the middle of the broad southern outer
ejecta knot gap.


title: Extremely High Energy Cosmic Neutrinos and Relic Neutrinos

abstract:
  I review the essentials of ultrahigh-energy neutrino interactions, show how
neutral-current detection and flavor tagging can enhance the scientific
potential of neutrino telescopes, and sketch new studies on neutrino encounters
with dark matter relics and on gravitational lensing of neutrinos.


title: What mass are the smallest protohalos?

abstract:
  We calculate the kinetic-decoupling temperature for weakly interacting
massive particles (WIMPs) in supersymmetric (SUSY) and
universal-extra-dimension (UED) models that can account for the
cold-dark-matter abundance determined from cosmic microwave background
measurements. Depending on the parameters of the particle-physics model, a wide
variety of decoupling temperatures is possible, ranging from several MeV to a
few GeV. These decoupling temperatures imply a range of masses for the smallest
protohalos much larger than previously thought -- ranging from 10^{-6} earth
masses to 10^{2} earth masses. We expect the range of protohalos masses derived
here to be characteristic of most particle-physics models that can thermally
accommodate the required relic abundance of WIMP dark matter, even beyond SUSY
and UED.


title: Chandra and Hubble Space Telescope Study of the Globular Cluster NGC 288

abstract:
  We report on the Chandra X-ray Observatory observations of the globular
cluster NGC 288. We detect four X-ray sources within the core radius and seven
additional sources within the half-mass radius down to a limiting luminosity of
Lx=7e30 erg/s (assuming cluster membership) in the 0.3-7 keV band. We also
observed the cluster with the Hubble Space Telescope Advanced Camera for
Surveys and identify optical counterparts to seven X-ray sources out of the
nine sources within the HST field-of-view. Based on the X-ray and optical
properties, we find 2-5 candidates of cataclysmic variables (CVs) or
chromospherically active binaries, and 2-5 background galaxies inside the
half-mass radius. Since the core density of NGC 288 is very low, the faint
X-ray sources of NGC 288 found in the Chandra and HST observations is higher
than the prediction on the basis of the collision frequency. We suggest that
the CVs and chromospherically active binaries are primordial in origin, in
agreement with theoretical expectation.


title: Cyclic evolution of radio pulsars on the time scale of hundreds of years

abstract:
  The recent massive measurements of pulsar frequency second derivatives have
shown that they are 100-1000 times larger than expected for standard pulsar
slowdown low. Moreover, the second derivatives as well as braking indices are
even negative for about half of pulsars. We explain these paradoxical results
on the basis of the statistical analysis of the rotational parameters $\nu$,
$\dot \nu$ and $\ddot \nu$ of the subset of 295 pulsars taken mostly from the
ATNF database. We have found strong correlation of $\ddot \nu$ and $\dot \nu$
either for $\ddot\nu > 0$ (correlation coefficient $r\approx0.9$) and $\ddot\nu
< 0$ ($r\approx0.85$), and of $\nu$ and $\dot\nu$ ($r\approx0.7$). We interpret
these dependencies as evolutionary ones due to $\dot\nu$ being nearly
proportional to characteristic age $\tau_{ch}$. The derived statistical
relations as well as "anomalous" values of $\ddot\nu$ are well explained in the
framework of the simple model of cyclic evolution of the rotational frequency
of the pulsars. It combines the secular change of $\nu_{tr}(t)$,
$\dot\nu_{tr}(t)$ and $\ddot\nu_{tr}(t)$ according to the power law with
$n\approx5$ and harmonic oscillations of 100--1000 years period with an
amplitude from $10^{-3}$ Hz for young pulsars to $10^{-10}$ Hz for elder ones.
The physical nature of these cyclic variations of the rotational frequency may
be similar to the well-known red timing noise, however, with much larger
characteristic time scale.


title: When Extrasolar Planets Transit Their Parent Stars

abstract:
  When extrasolar planets are observed to transit their parent stars, we are
granted unprecedented access to their physical properties. It is only for
transiting planets that we are permitted direct estimates of the planetary
masses and radii, which provide the fundamental constraints on models of their
physical structure. In particular, precise determination of the radius may
indicate the presence (or absence) of a core of solid material, which in turn
would speak to the canonical formation model of gas accretion onto a core of
ice and rock embedded in a protoplanetary disk. Furthermore, the radii of
planets in close proximity to their stars are affected by tidal effects and the
intense stellar radiation. As a result, some of these "hot Jupiters" are
significantly larger than Jupiter in radius. Precision follow-up studies of
such objects (notably with the space-based platforms of the Hubble and Spitzer
Space Telescopes) have enabled direct observation of their transmission spectra
and emitted radiation. These data provide the first observational constraints
on atmospheric models of these extrasolar gas giants, and permit a direct
comparison with the gas giants of the Solar system. Despite significant
observational challenges, numerous transit surveys and quick-look radial
velocity surveys are active, and promise to deliver an ever-increasing number
of these precious objects. The detection of transits of short-period
Neptune-sized objects, whose existence was recently uncovered by the
radial-velocity surveys, is eagerly anticipated. Ultra-precise photometry
enabled by upcoming space missions offers the prospect of the first detection
of an extrasolar Earth-like planet in the habitable zone of its parent star,
just in time for Protostars and Planets VI.


title:
Early-Time Photometry and Spectroscopy of the Fast Evolving SN 2006AJ
  Associated with GRB 060218

abstract:
  We present early photometric and spectroscopic data on the afterglow of GRB
060218 and report the evolution of the underlying supernova 2006aj. Our data
span a time-range of 4 days to 22 days after the GRB and clearly establish that
SN 2006aj is a fast-evolving broad-lined Type Ic SN with an extremely short
rise-time (~ 10 days) and a large optical luminosity (M_V = -18.7 mag). The SN
properties are deduced well since the GRB afterglow does not contribute a
significant amount to the total light output. The spectra show broad lines
indicative of large expansion velocities, but are better matched by those of SN
2002ap and SN 1997ef (that are not associated with a GRB) than those of the
proto-typical GRB-related SN 1998bw. We refine the redshift estimate to z =
0.0335 +/- 0.00007. The host-galaxy is a low-metallicity dwarf galaxy (with M_V
\~ -16.0 mag), similar to host-galaxies of other GRB-associated SNe.


title: The Unusual X-ray Spectrum of FU Orionis

abstract:
  FU Orionis stars (FUors) are young low-mass eruptive stars that are thought
to be accreting at high rates. They could give rise to soft X-ray emission from
accretion shocks, but their X-ray properties are largely unknown. We report the
first X-ray detection of the prototype star FU Orionis with XMM-Newton. Its
X-ray spectrum is unusual compared to those of classical T Tauri stars (cTTS).
The cool and hot components typically detected in cTTS are present but are seen
through different absorption column densities. A heavily-absorbed hot component
at kT > 5 keV accounts for most of the observed flux and a strong Fe K emission
line is present. Such high temperatures are characteristic of magnetic
processes rather than shock emission. We discuss possible origins of the
unusual spectrum in the context of a complex physical environment that likely
includes disk accretion, a strong wind, magnetic activity, and close binarity.


title:
Polarization Observations of the Anomalous Microwave Emission in the
  Perseus Molecular Complex with the Cosmosomas Experiment

abstract:
  The anomalous microwave emission detected in the Perseus molecular complex by
Watson \ea has been observed at 11 GHz through dual orthogonal polarizations
with the COSMOSOMAS experiment. Stokes U and Q maps were obtained at a
resolution of \sim 0.9deg. for a 30deg. X 30deg. region including the Perseus
molecular complex. A faint polarized emission has been measured; we find Q=-0.2
% \pm1.0%, while U=-3.4^{+1.8}_{-1.4}% both at the 95% confidence level with a
systematic uncertainty estimated to be lower than 1% determined from tests of
the instrumental performance using unpolarized sources in our map as null
hypothesis. The resulting total polarization level is \Pi = 3.4^{+1.5}_{-1.9}%.
These are the first constraints on the polarization properties of an anomalous
microwave emission source. The low level of polarization seems to indicate that
the particles responsible for this emission in the Perseus molecular complex
are not significantly aligned in a common direction over the whole region, as a
consequence of either a high structural symmetry in the emitting particle or a
low-intensity magnetic field. Our weak detection is fully consistent with
predictions from electric dipole emission and resonance relaxation at this
frequency.


title: Associations of Dwarf Galaxies

abstract:
  Hubble Space Telescope Advanced Cameras for Surveys has been used to
determine accurate distances for 20 galaxies from measurements of the
luminosity of the brightest red giant branch stars. Five associations of dwarf
galaxies that had originally been identified based on strong correlations on
the plane of the sky and in velocity are shown to be equally well correlated in
distance. Two more associations with similar properties have been discovered.
Another association is identified that is suggested to be unbound through tidal
disruption. The associations have the spatial and kinematic properties expected
of bound structures with 1 - 10 x 10^11 solar mass. However, these entities
have little light with the consequence that mass-to-light ratios are in the
range 100 - 1000 in solar units. Within a well surveyed volume extending to 3
Mpc, all but one known galaxy lies within one of the groups or associations
that have been identified.


title: TEMPO2, a new pulsar timing package. I: Overview

abstract:
  Contemporary pulsar timing experiments have reached a sensitivity level where
systematic errors introduced by existing analysis procedures are limiting the
achievable science. We have developed tempo2, a new pulsar timing package that
contains propagation and other relevant effects implemented at the 1ns level of
precision (a factor of ~100 more precise than previously obtainable). In
contrast with earlier timing packages, tempo2 is compliant with the general
relativistic framework of the IAU 1991 and 2000 resolutions and hence uses the
International Celestial Reference System, Barycentric Coordinate Time and
up-to-date precession, nutation and polar motion models. Tempo2 provides a
generic and extensible set of tools to aid in the analysis and visualisation of
pulsar timing data. We provide an overview of the timing model, its accuracy
and differences relative to earlier work. We also present a new scheme for
predictive use of the timing model that removes existing processing artifacts
by properly modelling the frequency dependence of pulse phase.


title: Discovery of the Coolest Extreme Subdwarf

abstract:
  We report the discovery of LEHPM 2-59 as the coolest extreme M subdwarf
(esdM) found to date. Optical and near infrared spectroscopy demonstrate that
this source is of later spectral type than the esdM7 APMPM 0559-2903, with the
presence of strong alkali lines (including Rb I), VO absorption at 7400 A and
H2O absorption at 1.4 microns. Current optical classification schemes yield a
spectral type of esdM8, making LEHPM 2-59 one of only two ultracool esdMs
known. The substantial space velocity of this object (V_galactic ~ -180 km/s)
identifies it as a halo star. Spectral model fits to the optical and near
infrared spectral data for this and four other late-type esdMs indicate that
LEHPM 2-59 is the coolest esdM currently known, with Teff = 2800-3000 K and
-1.5 <~ [M/H] <~ -2.0. Comparison of Teff determinations for M dwarfs and esdMs
based on spectral model fits from this study and the literature demonstrate a
divergence in Teff scales beyond spectral types M5/esdM5, as large as 600-800 K
by types M8/esdM8. While this divergence is likely an artifact of the
underlying classification scheme, it may lead to systematic errors in the
derived properties of intermediate metallicity subdwarfs. We comment on the
future of ultracool subdwarf classification, and suggest several ideas for
addressing shortcomings in current (largely extrapolated) schemes.


title: Effects of sedimented helium on the X-ray properties of galaxy clusters

abstract:
  In this Letter, we consider the role played by the sedimentation of helium
nuclei on the emissivity and metallicity distribution of the X-ray emitting
plasma in the cores of relaxed galaxy clusters. We model the gas density and
temperature profiles of nearby cooling core clusters to estimate the
gravitational acceleration acting on the helium and show that its sedimentation
time scale is too long with respect to the present age of these objects to play
a significant role. However, we argue that these time scales have to be
definitely lower in the past allowing the helium to settle in the cluster
cooling cores and raise its abundance to values higher than the solar one. A
direct consequence of this speculation is that the helium, by increasing the
total X-ray emissivity, reduces the measured metal abundance in the inner (r <
20 kpc) cluster regions.


title: Water vapor on supergiants. The 12 micron TEXES spectra of mu Cephei

abstract:
  Several recent papers have argued for warm, semi-detached, molecular layers
surrounding red giant and supergiant stars, a concept known as a MOLsphere.
Spectroscopic and interferometric analyses have often corroborated this general
picture. Here, we present high-resolution spectroscopic data of pure rotational
lines of water vapor at 12 microns for the supergiant mu Cephei. This star has
often been used to test the concept of molecular layers around supergiants.
Given the prediction of an isothermal, optically thick water-vapor layer in
Local Thermodynamic Equilibrium around the star (MOLsphere), we expected the 12
micron lines to be in emission or at least in absorption but filled in by
emission from the molecular layer around the star. Our data, however, show the
contrary; we find definite absorption. Thus, our data do not easily fit into
the suggested isothermal MOLsphere scenario. The 12 micron lines, therefore,
put new, strong constraints on the MOLsphere concept and on the nature of water
seen in signatures across the spectra of early M supergiants. We also find that
the absorption is even stronger than that calculated from a standard,
spherically symmetric model photosphere without any surrounding layers. A cool
model photosphere, representing cool outer layers is, however, able to
reproduce the lines, but this model does not account for water vapor emission
at 6 microns. Thus, a unified model for water vapor on mu Cephei appears to be
lacking. It does seem necessary to model the underlying photospheres of these
supergiants in their whole complexity. The strong water vapor lines clearly
reveal inadequacies of classical model atmospheres.


title:
Outer structure of the Galactic warp and flare: explaining the Canis
  Major over-density

abstract:
  (Abridged) We derive the structure of the Galactic stellar Warp and Flare
using 2MASS RC and RGB stars, selected at mean heliocentric distances of 3, 7
and 17 kpc.
  Our results are: (i) a clear stellar warp signature is derived for the 3
selected rings; (ii) the derived stellar warp is consistent (both in amplitude
and phase-angle) with that for the Galactic interstellar dust and HI gas; (iii)
the Sun seems not to fall on the line of nodes. The stellar warp phase-angle
orientation (+15 degrees) is close to the orientation angle of the Galactic bar
and this produces an asymmetric warp for the inner rings; (iv) a
Northern/Southern warp symmetry is observed only for the ring at 17 kpc; (v)
treating a mixture of thin and thick disk populations we trace the disk flaring
and derive a constant scale-height (~0.65 kpc) within R(GC)~15 kpc. Further
out, the disk flaring increase gradually reaching a mean scale-height of ~1.5
kpc at R(GC)~23 kpc; and (vi) these results provide further robust evidence
that there is no disk radial truncation at R(GC)~14 kpc.
  In the particular case of the Canis Major over-density we confirm its
coincidence with the Southern stellar maximum warp occurring near l=240. We
present evidence to conclude that all observed parameters (e.g. number density,
radial velocities, proper motion etc) of CMa are consistent with it being a
normal Milky Way outer-disk population, thereby leaving no justification for a
more complex interpretations of its origin. The present analysis does not
provide a conclusive test of the structure or origin of the Monoceros Ring.
Nevertheless, we show that a warped flared Milky Way contributes significantly
at the locations of the Monoceros Ring.


title:
The unprecedented optical outburst of the quasar 3C 454.3. The WEBT
  campaign of 2004-2005

abstract:
  The radio quasar 3C 454.3 underwent an exceptional optical outburst lasting
more than 1 year and culminating in spring 2005. The maximum brightness
detected was R = 12.0, which represents the most luminous quasar state thus far
observed (M_B ~ -31.4). In order to follow the emission behaviour of the source
in detail, a large multiwavelength campaign was organized by the Whole Earth
Blazar Telescope (WEBT). Continuous optical, near-IR and radio monitoring was
performed in several bands. ToO pointings by the Chandra and INTEGRAL
satellites provided additional information at high energies in May 2005. The
historical radio and optical light curves show different behaviours. Until
about 2001.0 only moderate variability was present in the optical regime, while
prominent and long-lasting radio outbursts were visible at the various radio
frequencies, with higher-frequency variations preceding the lower-frequency
ones. After that date, the optical activity increased and the radio flux is
less variable. This suggests that the optical and radio emissions come from two
separate and misaligned jet regions, with the inner optical one acquiring a
smaller viewing angle during the 2004-2005 outburst. Moreover, the colour-index
behaviour (generally redder-when-brighter) during the outburst suggests the
presence of a luminous accretion disc. A huge mm outburst followed the optical
one, peaking in June-July 2005. The high-frequency (37-43 GHz) radio flux
started to increase in early 2005 and reached a maximum at the end of our
observing period (end of September 2005). VLBA observations at 43 GHz during
the summer confirm the


title:
Towards a new tool for the indirect detection of Dark Matter: building
  of a SuSy spectrum generator based on micrOMEGAs

abstract:
  In the quest for indirect signals from dark matter annihilation, powerful
computation codes are required. I report here a new code based on micrOMEGAs
devoted to the analysis of such signals in term of Supersymmetry. It computes
gamma rays and positrons fluxes in a general SuSy model, as well as the other
charged cosmic rays and neutrinos source terms. This work aims to propose an
alternative to the DarkSUSY code by providing inclusive signals from SuSy for
dark matter indirect searches. Therefore it can be used for sensitivity studies
and data analysis.


title:
Evidence for T Tauri-like emission in the EXor V1118 Ori from near-IR
  and X-ray data

abstract:
  We present a near-IR study of the EXor variable V1118 Ori, performed by
following a slightly declining phase after a recent outburst. In particular,
the near-IR (0.8 - 2.3 micron) spectrum, obtained for the first time, shows a
large variety of emission features of the HI and HeI recombination and CO
overtone. By comparing the observed spectrum with a wind model, a mass loss
rate value is derived along with other parameters whose values are typical of
an accreting T Tauri star. In addition, we have used X-ray data from the XMM
archive, taken in two different epochs during the declining phase monitored in
IR. X-ray emission (in the range 0.5 - 10 keV) permits to derive several
parameters which confirm the T Tauri nature of the source. In the near-IR the
object maintains a low visual extinction during all the activity phases,
confirming that variable extinction does not contribute to brightness
variations. The lack of both a significant amount of circumstellar material and
any evidence of IR cooling from collimated jet/outflow driven by the source,
indicates that, at least this member of the EXor class, is in a late stage of
the Pre-Main Sequence evolution. In the X-ray regime, an evident fading is
present, detected in the post-outburst phase, that cannot be reconciled with
the presence of any absorbing material. This circumstance, combined with the
persistence (in the pre- and post-outburst phases) of a temperature component
at about 10 MK, suggests that accretion has some influence in regulating the
coronal activity.


title:
1.4 GHz polarimetric observations of the two fields imaged by the DASI
  experiment

abstract:
  We present results of polarization observations at 1.4 GHz of the two fields
imaged by the DASI experiment ($\alpha = 23^{\rm h} 30^{\rm m}$, $\delta =
-55^{\circ}$ and $\alpha = 00^{\rm h} 30^{\rm m}$, $\delta = -55^{\circ}$,
respectively). Data were taken with the Australia Telescope Compact Array with
3.4 arcmin resolution and $\sim 0.18$ mJy beam$^{-1}$ sensitivity. The emission
is dominated by point sources and we do not find evidence for diffuse
synchrotron radiation even after source subtraction. This allows to estimate an
upper limit of the diffuse polarized emission. The extrapolation to 30 GHz
suggests that the synchrotron radiation is lower than the polarized signal
measured by the DASI experiment by at least 2 orders of magnitude. This further
supports the conclusions drawn by the DASI team itself about the negligible
Galactic foreground contamination in their data set, improving by a factor
$\sim 5$ the upper limit estimated by Leitch et al. (2005).
  The dominant point source emission allows us to estimate the contamination of
the CMB by extragalactic foregrounds. We computed the power spectrum of their
contribution and its extrapolation to 30 GHz provides a framework where the CMB
signal should dominate. However, our results do not match the conclusions of
the DASI team about the negligibility of point source contamination, suggesting
to take into account a source subtraction from the DASI data.


title: The Jets and and Supercritical Accretion Disk in SS433

abstract:
  (abridged) The review describes observations of SS433. The main difference
between SS433 and other X-ray binaries is the supercritical regime for the gas
accretion onto the relativistic star (most likely a black hole), which has lead
to the formation of collimated relativistic jets. The properties of the jets
are determined by their interaction with the disk wind. The precession of the
disk and jets, as well as the eclipsing in the binary system, make SS433 a
unique laboratory for studies of mechanisms for the microquasar phenomenon.
Essentially all photometric and spectroscopic properties of SS433 are
determined by the accretion disk and its orientation, but the disk itself is
not observed, being located beneath the photosphere of the dense wind.
Observational manifestations of the wind and of gas flows in the system are
described. Little is known about the structure of the central regions where the
hot bases of the jets are located. The available X-ray, UV, and optical
observations point towards the picture where the bases of the jets are
surrounded by cocoons of hot gas reradiating emission from the inner regions of
the jet channel. Direct investigations of this channel in the supercritical
accretion disk of SS433 are not possible; however, a similar object oriented
face-on would likely be an extremely bright X-ray source, such as
ultra-luminous X-ray sources observed in other galaxies.


title: Dwarf galaxies in the Antlia Cluster: First results

abstract:
  We present the first results of a project aimed to study the galaxy
population of the Antlia cluster, the third nearest galaxy cluster after Virgo
and Fornax. The observations for the Antlia project consist of Washington
wide-field images taken with the MOSAIC camera mounted at the prime focus of
the CTIO 4-m Blanco telescope. Our preliminary results correspond to the
identification and classification of dwarf galaxies in the central cluster
region, extending the list of Ferguson & Sandage (1990). The final aim of our
project is to study the luminosity function, morphology and structural
parameters of dwarf galaxies in the Antlia cluster with a more complete sample.


title:
Determination of the Hubble constant, the intrinsic scatter of
  luminosities of Type Ia SNe, and evidence for non-standard dust in other
  galaxies

abstract:
  A sample of 109 type Ia supernovae (SNe Ia) with recession velocity < 30,000
km s^{-1}, is compiled from published SNe Ia light curves to explore the
expansion rate of the local Universe. Based on the color parameter delta C_{12}
and the decline rate delta m_{15}, we found that the average absorption to
reddening ratio for SN Ia host galaxies to be R_{UBVI} = 4.37+/-0.25,
3.33+/-0.11, 2.30+/-0.11, 1.18+/-0.11, which are systematically lower than the
standard values in the Milky Way. We investigated the correlations of the
intrinsic luminosity with light curve decline rate, color index, and supernova
environmental parameters. In particular, we found SNe Ia in E/S0 galaxies to be
brighter close to the central region than those in the outer region, which may
suggest a possible metallicity effect on SN luminosity. The dependence of SN
luminosity on galactic environment disappears after corrections for the
extinction and delta C_{12}. The Hubble diagrams constructed using 73 Hubble
flow SNe Ia yield a 1-sigma scatter of <0.12 mag in BVI bands and ~0.16 mag in
U band. The luminosity difference between normal SNe Ia and peculiar objects
(including SN 1991bg-like and 1991T-like events) has now been reduced to within
0.15 mag via delta C_{12} correction. We use the same precepts to correct the
nearby SNe Ia with Cepheid distances and found that the fully corrected
absolute magnitudes of SNe Ia are: M_{B} = -19.33+/-0.06 mag, M_{V} =
-19.27+/-0.05 mag. We deduced a value for the Hubble constant of H_{0} = 72 +/-
6 (total) km s^{-1} Mpc^{-1}.


title: Probing Inflation and Dark Energy with Current Cosmological Observations

abstract:
  It is commonly believed that our Universe has experienced two different
stages of accelerated expansion. The early stage is known as inflation and the
current acceleration is driven by dark energy. Observing inflation and dark
energy dynamics are among the most important aspects of the current
cosmological research. In this paper we make a first detailed probe of possible
degeneracies between dynamical inflation and dark energy in light of current
cosmological observations. We find the inclusion of inflation and dark energy
parameters together make the parameter spaces broader, but interestingly
deviation from scale-invariant primordial spectrum is sightly more favored by
current cosmological observations when one marginalizes over dynamical dark
energy models.


title: Detection of Ks-excess stars in the 14Myr open cluster NGC4755

abstract:
  We derive the structure, distribution of MS and PMS stars and dynamical state
of the young open cluster NGC 4755. We explore the possibility that, at the
cluster age, some MS and PMS stars still present infrared excesses related to
dust envelopes and proto-planetary discs. The radial density profile follows
King's law with a core radius $\rm\rc=0.7\pm0.1 pc$ and a limiting radius
$\rm\rl=6.9\pm0.1 pc$; the cluster age is $\rm14\pm2 Myr$. Field-star
decontamination reveals a low-MS limit at $\rm\approx1.4 \ms$. The core MF
($\chi=0.94\pm0.16$) is flatter than the halo's ($\chi=1.58\pm0.11$). NGC 4755
contains $\rm\sim285$ candidate PMS stars of age $\rm\sim1 - 15 Myr$, and a few
evolved stars. The mass locked up in PMS, MS and evolved stars amounts to
$\rm\sim1150 \ms$. Proper motions show that \ks-excess MS and PMS stars are
cluster members. \ks-excess fractions in PMS and MS stars are $\rm5.4\pm2.1%$
and $\rm3.9\pm1.5%$ respectively, consistent with the cluster age. The core is
deficient in PMS stars, as compared with MS ones. NGC 4755 hosts binaries in
the halo but they are scarce in the core. Compared to open clusters in
different dynamical states studied with similar methods, NGC 4755 fits
relations involving structural and dynamical parameters in the expected locus
for its age and mass. On the other hand, the flatter core MF probably
originates from primordial processes related to parent molecular cloud
fragmentation and mass segregation over $\rm\sim14 Myr$. Star formation in NGC
4755 began $\rm\approx14 Myr$ ago and proceeded for about the same length of
time. Detection of \ks-excess emission in member MS stars suggests that some
circumstellar dust discs survived for $\rm\sim10^7 yr$, occurring both in some
MS and PMS stars for the age and spread observed in NGC 4755.


title:
Dust in spiral disks: opacity profiles from FIR emission and counts of
  distant galaxies

abstract:
  Dust emission in the far-infrared (FIR) characterizes the temperature and
quantity of interstellar dust in a spiral disk. The three Spitzer/MIPS bands
are well suited to measuring the gradient in temperature and the total optical
depth in the disk of a spiral galaxy. Another way to estimate the quantity of
dust in a spiral disk is the "Synthetic Field Method" (SFM, Gonzalez et al.
1998), which uses the number of distant field galaxies seen through the disk of
the nearby spiral. The optical depth estimated from this method can be compared
to the values derived from the FIR emission. Since the two techniques depend on
different assumptions regarding the dust geometry and emissivity, this
comparison between the optical depth profiles can potentially shed light on the
structure and quantity of the ISM in spiral disks, especially any colder
components. The dust responsible for the opacity from distant galaxy counts
appears to be predominantly cold (T < 20 K.). The differences between the
radial absorption profiles can be explained by spiral arms in the SFM
measurements. Taken over the same aperture, galaxy counts show higher
extinction values than the FIR derived ones. The implications for dust geometry
can hopefully be explored with a more rigorous estimate of dust mass from the
FIR fluxes.


title: Infrared Surface Brightness Analysis of Galaxies in Compact Groups

abstract:
  Images of 7 Compact groups of galaxies (CG) were obtained using the 2.1m
telescope in San Pedro Martir (B.C. Mexico) equipped with the NIR camera
CAMILA. The NIR images trace the mass of the galaxies, through the oldest and
more evolved stellar populations. The goal of this project is to search for
evidence of morphological perturbations correlated with the level of activity
(AGN or star formation) of the galaxies. We find that the level of perturbation
is well correlated with activity observed in optical spectrocopy (Coziol et al.
2004). Evidence for perturbations decreases from more active groups to less
active groups, confirming the classification. Our analysis suggests that
galaxies in more active groups are undergoing important transformations due to
interaction and merging and that the whole groups is on a merger path. Galaxies
in less active CG have gone through similar processes in the recent past and
are either in a final merging phase or in equilibrium due to a more massive
halo of dark matter.


title: Rebuttal to: Has dark energy really been discovered in the Lab?

abstract:
  We argue that a recent discussion of Jetzer and Straumann [Phys. Lett. B 606,
77 (2005)] relating the measured noise spectrum in Josephson junctions to van
der Waals forces is incorrect. The measured noise spectrum in Josephson
junctions is a consequence of the fluctuation dissipation theorem and the
Josephson effect and has nothing to do with van der Waals forces. Consequently,
the argument of Jetzer and Straumann does not shed any light on whether dark
energy can or cannot be measured using superconducting Josephson devices. We
also point out that a more recent paper of Jetzer and Straumann [Phys. Lett. B
639, 57 (2006)] claiming that `zeropoint energies do not show up in any
application of the fluctuation dissipation theorem' violates the standard view
on the subject.


title:
Selfgravitating Gas Spheres in a Box and Relativistic Clusters: Relation
  between Dynamical and Thermodynamical Stability

abstract:
  We derive a variational principle for the dynamical stability of a cluster as
a gas sphere in a box. Newtonian clusters are always dynamically stable and,
for relativistic clusters, the relation between dynamical and thermodynamical
instabilities is analyzed. The boundaries between dynamically and
thermodynamically stable and unstable models are found numerically for
relativistic stellar systems with different cut off parameters. A criterion
based on binding energy curve is used for determination of the boundary of
dynamical stability.


title:
Opening a New Window to Fundamental Physics and Astrophysics: X-ray
  Polarimetry

abstract:
  An extensive theoretical literature predicts that X-ray Polarimetry can
directly determine relevant physical and geometrical parameters of
astrophysical sources, and discriminate between models further than allowed by
spectral and timing data only. X-ray Polarimetry can also provide tests of
Fundamental Physics. A high sensitivity polarimeter in the focal plane of a New
Generation X-ray telescope could open this new window in the High Energy Sky.


title:
Probing Star Formation in Interacting Galaxies Using UV and Mid-IR: The
  Case of Arp 82

abstract:
  To help understand the effects of galaxy interactions on star formation, we
analyze Spitzer infrared and GALEX ultraviolet images of the interacting galaxy
pair Arp 82 (NGC 2535/6), and compare to a numerical simulation of the
interaction. We investigate the UV and IR properties of several star forming
regions (clumps). Using the FUV/NUV colors of the clumps we constrain the ages.
The 8 micron and 24 micron luminosities are used to estimate the far-infrared
luminosities and the star formation rates of the clumps. We investigate
possible gradients in the UV and IR colors. See Smith et al. (2006a,b) for
global results on our entire interacting sample.


title: Adaptive Optics Imaging Survey of Luminous Infrared Galaxies

abstract:
  We present high resolution imaging observations of a sample of previously
unidentified far-infrared galaxies at z < 0.3. The objects were selected by
cross-correlating the IRAS Faint Source Catalog with the VLA FIRST catalog and
the HST Guide Star Catalog to allow for adaptive optics observations. We found
two new ULIGs (with L_FIR equal to or greater than 10^{12} L_sun) and 19 new
LIGs (with L_FIR equal to or greater than 10^{11} L_sun). Twenty of the
galaxies in the sample were imaged with either the Lick or Keck adaptive optics
systems in H or K'. Galaxy morphologies were determined using the two
dimensional fitting program GALFIT and the residuals examined to look for
interesting structure. The morphologies reveal that at least 30% are involved
in tidal interactions, with 20% being clear mergers. An additional 50% show
signs of possible interaction. Line ratios were used to determine powering
mechanism; of the 17 objects in the sample showing clear emission lines - four
are active galactic nuclei and seven are starburst galaxies. The rest exhibit a
combination of both phenomena.


title:
Phenomenological Modeling of the FIR-Radio Correlation within Nearby
  Galaxies

abstract:
  We present an analysis of the far-infrared (FIR)-radio correlation within a
group of nearby star-forming galaxy disks observed as part of the {\it Spitzer}
Infrared Nearby Galaxies Survey (SINGS). In our study we critically test a
phenomenological model for the FIR-radio correlation which describes the radio
image as a smeared version of the infrared image. The physical basis for this
model is that cosmic-ray electrons (CR electrons) will diffuse significant
distances from their originating sources before decaying by synchrotron
emission. We find that this description generally works well, improving the
correlation between the radio and infrared images of our four sample galaxies
by an average factor of $\sim$1.6. We also find that the best-fit smearing
kernels seem to show a dependence on the ongoing star formation activity within
each disk. Galaxies having lower star formation activity (NGC 2403 and NGC
3031) are best-fit using larger smearing kernels than galaxies with more active
star-forming disks (NGC 5194 and NGC 6946). We attribute this trend to be due
to a recent deficit of CR electron injection into the interstellar medium of
galaxies with lower star formation activity throughout their disks.


title: Inflationary Potential Reconstruction for a WMAP Running Power Spectrum

abstract:
  The first year WMAP measurement of the CMB temperature anisotropy is
intriguingly consistent with a larger running of the inflationary scalar
spectral index than would be expected for single-field inflation. We revisit
the issue of a large running spectral index, first by reexamining the evidence
from the data, and then by reconstructing the inflationary potential, using an
improved method based upon the Hamilton-Jacobi formulation. We note that a
spectrum which runs only over 1.5 decades of k space provides as good a fit to
the CMB data as one which runs at all k, that significant evidence for running
comes from multipoles l near 40, and that large running gives a better fit than
a flat spectrum primarily if the tensor-to-scalar ratio $r$ is large, r ~ 0.5,
and the field values are at the Planck scale. This allows one to break the
large degeneracy of potentials which would be consistent with the scalar power
alone. Large running, should it be confirmed, is thus linked to a high scale of
inflation and the possibility of seeing effects of tensor modes in the CMB and
Planck-scale physics. Nevertheless, we show that the reconstructed inflaton
potential is well-described by a renormalizable potential whose quantum
corrections are under control despite the large field values.


title: Outflows from Massive YSOs as Seen with the Infrared Array Camera

abstract:
  The bipolar outflow from the massive star forming cluster in DR21 is one of
the most powerful known, and in IRAC images the outflow stands out by virtue of
its brightness at 4.5 um (Band 2). Indeed, IRAC images of many galactic and
extragalactic star formation regions feature prominent Band 2 morphologies. We
have analyzed archival ISOSWS spectra of the DR21 outflow, and compare them to
updated H2 shocked and UV-excitation models. We find that H2 line emission
contributes about 50% of the flux of the IRAC bands at 3.6 um, 4.5 um , and 5.8
um, and is a significant contributor to the 8.0 um band as well, and confirm
that the outflow contains multiple excitation mechanisms. Other potentially
strong features, in particular Br alpha and CO emission, have been suggested as
contributing to IRAC fluxes in outflows, but they are weak or absent in DR21;
surprisingly, there also is no evidence for strong PAH emission. The results
imply that IRAC images can be a powerful detector of, and diagnostic for,
outflows caused by massive star formation activity in our galaxy, and in other
galaxies as well. They also suggest that IRAC color-color diagnostic diagrams
may need to take into account the possible influence of these strong emission
lines. IRAC images of the general ISM in the region, away from the outflow, are
in approximate but not precise agreement with theoretical models.


title: Simulated Molecular Gas Emission in Galaxy Mergers with Embedded AGN

abstract:
  We investigate the effect of embedded active galactic nuclei (AGN) in galaxy
mergers on the CO molecular line emission by combining non-local thermodynamic
equilibrium (LTE) radiative transfer calculations with hydrodynamic
simulations. We find that AGN feedback energy in gas rich galaxy mergers can
contribute to large molecular outflows which may be detectable via
velocity-integrated emission contour maps, as well as through kinematic
features in the emission line profiles.


title: Statistical Isotropy of CMB Polarization Maps

abstract:
  We formulate statistical isotropy of CMB anisotropy maps in its most general
form. We also present a fast and orientation independent statistical method to
determine deviations from statistical isotropy in CMB polarization maps.
Importance of having statistical tests of departures from SI for CMB
polarization maps lies not only in interesting theoretical motivations but also
in testing cleaned CMB polarization maps for observational artifacts such as
residuals from polarized foreground emission. We propose a generalization of
the Bipolar Power Spectrum (BiPS) to polarization maps. Application to the
observed CMB polarization maps will be soon possible after the release of WMAP
three year data. As a demonstration we show that for E-polarization this test
can detect breakdown of statistical isotropy due to polarized synchrotron
foreground.


title:
A New Method to Calibrate the Magnitudes of Type Ia Supernovae at
  Maximum Light

abstract:
  We present a new empirical method for fitting multicolor light curves of Type
Ia supernovae. Our method combines elements from two widely used techniques in
the literature: the delta_m15 template fitting method and the Multicolor
Light-Curve Shape method. An advantage of our technique is the ease of adding
new colors, templates, or parameters to the fitting procedure. We use a large
sample of published light curves to calibrate the relations between the
absolute magnitudes at maximum and delta_m15 in BVRI filters. We find that
individual subsamples from a given survey or publication have significantly
tighter relationships between light curve shape and luminosity than the
relationship derived from the sum of all the samples, pointing to uncorrected
systematic errors in the photometry, mainly in BV filters. Using our method, we
calculate luminosity distances and host galaxy reddening to 89 SNe in the
Hubble flow and construct a low-z Hubble diagram. The dispersion of the SNe in
the Hubble diagram is 0.20 mag, or an error of ~9% in distance to a single SN.
Our technique produces similar or smaller dispersion in the low-z Hubble
diagram than other techniques in the literature.


title: The Spitzer Spirals, Bridges, and Tails Interacting Galaxy Survey

abstract:
  We present Spitzer mid-infrared images from a survey of three dozen
pre-merger strongly interacting galaxy pairs selected from the Arp Atlas. The
global mid-infrared colors of these galaxies and their tidal tails and bridges
are similar to those of normal spiral galaxies, thus this optically selected
sample of interacting galaxies does not have strongly enhanced normalized star
formation rates in their disks or tidal features. Despite distortion and
disturbance these systems continue to form stars at a normal rate on average.
The morphology of these galaxies is generally smoother in the shorter
wavelength IRAC bands than at 8 $\mu$m, where dozens of clumps of star
formation are detected.


title: Using Spitzer to probe the nature of submillimetre galaxies in GOODS-N

abstract:
  How does the submm galaxy population detected by SCUBA fit into galaxy
evolution? How do these rare starbursting systems, which contribute
significantly to high redshift star-formation, relate to other galaxy
populations? Deep radio observations have been most useful for studying these
systems, but still leave a significant fraction of the population unidentified.
Now with the deep IRAC and MIPS images from the GOODS Spitzer Legacy program
and a re-analysis of the deep radio data, we are able to identify counterparts
for a large fraction of SCUBA galaxies in GOODS-N. All of these counterparts
are detected by Spitzer. Given the vast multi-wavelength data in this field, we
can study the spectral energy distributions (SEDs) of these systems and
determine what is fueling their intense infrared luminosities. A rest-frame
composite optical-to-radio SED for all spectroscopically identified submm
sources shows that the average SCUBA galaxy is consistent with models of
ultraluminous starburst galaxies, although cooler than those observed locally.
Because of this, the submm flux alone consistently overestimates IR when using
spectral templates which obey the local ULIRG temperature-luminosity relation.
The wide range of 24/850 micron flux ratios as a function of redshift indicates
the presence of strong mid-IR features, to be confirmed with deep IRS
spectroscopy. The IRAC colours of the submm systems provide useful redshift
constraints, since, at these redshifts, IRAC samples the stellar bump. The
Spitzer photometry of this large sample of submm galaxies has allowed us to put
constraints on many of the outstanding issues in submm astronomy.