title:
The ELODIE survey for northern extra--solar planets I. 6 new
  extra--solar planet candidates

abstract:
  Precise radial-velocity observations at Haute-Provence Observatory (OHP,
France) with the ELODIE echelle spectrograph have been undertaken since 1994.
In addition to several discoveries described elsewhere, including and following
that of 51 Peg b, they reveal new sub-stellar companions with essentially
moderate to long periods. We report here about such companions orbiting five
solar-type stars (HD 8574, HD 23596, HD 33636, HD 50554, HD 106252) and one
sub-giant star (HD 190228). The companion of HD 8574 has an intermediate period
of 227.55 days and a semi--major axis of 0.77 AU. All other companions have
long periods, exceeding 3 years, and consequently their semi-major axes are
around or above 2 AU. The detected companions have minimum masses m2sini
ranging from slightly more than 2 M_Jup to 10.6 M_Jup. These additional objects
reinforce the conclusion that most planetary companions have masses lower than
5 M_Jup but with a tail of the mass distribution going up above 15 M_Jup. The
orbits are all eccentric and 4 out of 6 have an eccentricity of the order of
0.5. Four stars exhibit solar metallicity, one is metal-rich and one
metal-poor. With 6 new extra-solar planet candidates discovered, increasing
their total known to-date number to 115, the ELODIE Planet Search Survey yield
is currently 18. We emphasize that 3 out of the 6 companions could in principle
be resolved by diffraction-limited imaging on 8m-class telescopes depending on
the achievable contrast, and therefore be primary targets for first attempts of
extra-solar planet direct imaging.


title: XMM-Newton Observation of the Merging Galaxy Cluster A1644

abstract:
  An XMM-Newton imaging spectroscopy analysis of the galaxy cluster A1644 is
presented. A1644 is a complex merging system consisting of a main and a sub
cluster. A trail of cool, metal-rich gas has been discovered close to the sub
cluster. The combination of results from X-ray, optical, and radio data, and a
comparison to a hydrodynamical simulation suggest that the sub cluster has
passed by the main cluster off-axis and a fraction of its gas has been stripped
off during this process. Furthermore, for this merging system, simple effects
are illustrated which can affect the use of clusters as cosmological probes.
Specifically, double clusters may affect estimates of the cluster number
density when treated as a single system. Mergers, as well as cool cores, can
alter the X-ray luminosity and temperature measured for clusters, causing these
values to differ from those expected in equilibrium.


title:
The European Large Area ISO Survey (ELAIS): The Final Band-merged
  Catalogue

abstract:
  We present the final band-merged ELAIS catalogue at 6.7, 15, 90, and 175
$\mu$m, and the associated data at u,g,r,i,z,J,H,K, and 20cm. The origin of the
survey, infrared and radio observations, data-reduction and optical
identifications are briefly reviewed, and a summary of the area covered, and
completeness limit for each infrared band is given. A detailed discussion of
the band-merging and optical association strategy is given. The total
catalogues consists of 2860 sources. For extragalactic sources observed in 3 or
more infrared bands, colour-colour diagrams are presented and discussed in
terms of the contributing infrared populations. Spectral energy distributions
are shown for selected sources and compared with cirrus, M82 and Arp220
starburst, and AGN dust torus models.
  Spectroscopic redshifts are tabulated, where available. For the N1 and N2
areas, the INT ugriz Wide Field Survey, permits photometric redshifts to be
estimated for galaxies and quasars. These agree well with the spectroscopic
redshifts, within the uncertainty of the photometric method. The redshift
distribution is given for selected ELAIS bands and colour-redshift diagrams are
discussed.
  There is a high proportion of ultraluminous infrared galaxies in the ELAIS
Catalogue ($> 10 %$ of 15 $\mu$m sources), many with Arp220-like colours. 10
hyperluminous infrared galaxies and 10 EROs are found in the survey. The large
numbers of ultraluminous galaxies imply very strong evolution in the
star-formation rate between z = 0 and 1.


title: Palatini formulation of modified gravity with squared scalar curvature

abstract:
  In this paper we derive the Modified Friedmann equation in the Palatini
formulation of $R^2$ gravity. Then we use it to discuss the problem of whether
in Palatini formulation a $R^2$ term can drive an inflation. We show that the
Palatini formulation of $R^2$ gravity cannot lead to gravity-driven inflation.
If considering no zero radiation and matter energy densities, we show that only
under rather restrictive assumption about the radiation and matter energy
densities there will be a mild power-law inflation $a\sim t^2$.


title: Strong Gravitational Lensing and the Structure of Quasar Outflows

abstract:
  We show that by analyzing the spectra of lensed broad absorption line quasars
(BALQSOs), it is possible to reveal key properties of the outflowing gas in the
inner regions of these objects. This results from the fact that each image of
the quasar corresponds to a different line of sight through the outflow. This
combined with dynamical estimates for the location of the flow, adds new
information concerning the lateral, non line of sight structure of the
absorbing gas. Here we consider a sample of lensed BALQSOs and note that the
similarity of BAL profiles of different images of the same quasar implies that
the flow is relatively isotropic on small scales. We show that its geometry is
inconsistent with the ballistically accelerated spherical cloud model, and that
wind models provide a better description of the flow structure. Furthermore,
observations seem to disagree with naive interpretations of recent
time-dependent wind simulations. This may hint on several important physical
processes that govern the structure and dynamics of such flows. Future
prospects for the study of quasar outflows with the effect of strong
gravitational lensing are discussed.


title:
The orientation and magnitude of the orbital precession velocity of a
  binary pulsar system with double spins

abstract:
  The measurability of the spin--orbit (S--L) coupling induced orbital effect
is dependent on the orientation and magnitude of the orbital precession
velocity, ${\bf \Omega}_0$. This paper derives ${\bf \Omega}_0$ in the case
that both spins in the binary system contribute to the spin--orbit (S--L)
coupling, which is suitable for the most popular binary pulsars, Neutron
star--White Dwarf star (NS--WD) binaries (as well as for NS--NS binaries). This
paper shows that from two constraints, the conservation of the total angular
momentum and the triangle formed by the orbital angular momentum, ${\bf L}$,
the sum the spin angular momenta of the two stars, ${\bf S}$, and the total
angular momentum, ${\bf J}$, the orbital precession velocity, ${\bf \Omega}_0$,
along ${\bf J}$ is inevitable. Moreover, by the relation, $S/L\ll 1$, which is
satisfied for a general binary pulsar, a significant ${\bf \Omega}_0$ (in
magnitude) is inevitable, 1.5 Post Newtonian order (PN). Which are similar to
the case of one spin as discussed by many authors. However unlike the one spin
case, the magnitude of the precession velocity of ${\bf \Omega}_0$ varies
significantly due to the variation of the sum the spin angular momenta of the
two stars, ${\bf S}$, which can lead to significant secular variabilities in
binary pulsars.


title:
The Effects of Relativistic Corrections on Cosmological Parameter
  Estimations from SZE Cluster Surveys

abstract:
  Sunyaev-Zel'dovich Effect (SZE) cluster surveys are anticipated to yield
tight constraints on cosmological parameters such as the equation of state of
dark energy. In this paper, we study the impact of relativistic corrections of
the thermal SZE on the cluster number counts expected from a cosmological model
and thus, assuming that other cosmological parameters are known to high
accuracies, on the determination of the $w$ parameter and $\sigma_8$ from a SZE
cluster survey, where $w=p/\rho$ with $p$ the pressure and $\rho$ the density
of dark energy, and $\sigma_8$ is the rms of the extrapolated linear density
fluctuation smoothed over $8\hbox{Mpc}h^{-1}$. For the purpose of illustrating
the effects of relativistic corrections, our analyses mainly focus on $\nu=353
\hbox{GHz}$ and $S_{lim}=30\hbox{mJy}$, where $\nu$ and $S_{lim}$ are the
observing frequency and the flux limit of a survey, respectively. These
observing parameters are relevant to the {\it Planck} survey. It is found that
from two measurable quantities, the total number of SZE clusters and the number
of clusters with redshift $z\ge 0.5$, $\sigma_8$ and $w$ can be determined to a
level of $\pm 1%$ and $\pm 8%$, respectively, with $1\sigma$ uncertainties from
a survey of $10000\hbox{deg}^2$. Relativistic effects are important in
determining the central values of $\sigma_8$ and $w$. If we choose the two
quantities calculated relativistically from the flat cosmological model with
$\sigma_8=0.8284$ and $w=-0.75$ as input, the derived $\sigma_8$ and $w$ would
be 0.819 and -0.81, respectively, if relativistic effects are wrongly
neglected. The location of the resulting $\sigma_8$ and $w$ in the $\sigma_8-w$
plane is outside the $3\sigma$ region around the real central $\sigma_8$ and
$w$.


title: Kantowski-Sachs universe cannot be closed

abstract:
  In this paper, by analyzing the instability against spatially homogeneous and
anisotropic perturbations of the Kantowski-Sachs-type during different
cosmological epoch, we show that it is a theoretical consequence of the general
relativity that the KS universe must be open or flat if it underwent the matter
dominated and/or radiation dominated era in its past evolution, which
theoretically confirms the flatness of our observable universe.


title:
UV circular polarisation in star formation regions: the origin of
  homochirality?

abstract:
  Ultraviolet circularly polarised light has been suggested as the initial
cause of the homochirality of organic molecules in terrestrial organisms, via
enantiomeric selection of prebiotic molecules by asymmetric photolysis. We
present a theoretical investigation of mechanisms by which ultraviolet circular
polarisation may be produced in star formation regions. In the scenarios
considered here, light scattering produces only a small percentage of net
circular polarisation at any point in space, due to the forward throwing nature
of the phase function in the ultraviolet. By contrast, dichroic extinction can
produce a fairly high percentage of net circular polarisation (~10%) and may
therefore play a key role in producing an enantiomeric excess.


title:
The shallow slope of the z~6 quasar luminosity function: limits from the
  lack of multiple image gravitational lenses

abstract:
  We place a limit on the logarithmic slope of the luminous quasar luminosity
function at z~6 of beta>-3.0 (90%) using gravitational lensing constraints to
build on the limit of beta>-3.3 (90%) derived from an analysis of the
luminosity distribution (Fan et al. 2003). This tight constraint is obtained by
noting that of the two quasars which are lensed by foreground galaxies, neither
are multiply imaged. These observations are surprising if the luminosity
function is steep because magnification bias results in an overabundance of
multiply imaged relative to singly imaged lensed quasars. Our Bayesian analysis
uses the a-posteriori information regarding alignments with foreground galaxies
of the two lensed quasars, and provides a constraint on beta that is nearly
independent of the uncertain evolution in the lens population. The results
suggest that the bright end of the quasar luminosity function continues to
flatten out to z~6, as is observed between z~3 and z~5 (Fan et al. 2001).
Provided that SDSS J1148-5251 at z=6.37 is magnified by an intervening lens
galaxy at z~5 (White et al. 2003), we also show that the high lens redshift in
this system implies a co-moving density of massive galaxies that is close to
constant out to high redshift. This is in agreement with the lack of redshift
evolution in the velocity function of dark-matter halos with velocity
dispersions near 200 km/sec as predicted by the Press-Schechter formalism. The
combination of constraints on the quasar luminosity function and lens galaxy
evolution are used to compute an improved estimate for the z~6 multiple image
lens fraction of ~1-3%.


title: On the Quintessence with Abelian and Non-abelian Symmetry

abstract:
  We study the perturbations on both "radial" and "angular" components of the
quintessence with an internal abelian and non-abelian symmetry. The properties
of the perturbation on the "radial" component depend on the specific potential
of the model and is similiar for both abelian and non-abelian case. We show
that the consine-type potential is very interesting for the O(\textit{N})
quintessence model and also give a critical condition of instability for the
potential. While the properties of perturbations on "angular" components depend
on whether the internal symmetry is abelian or non-abelian, which we have
discussed respectively. In the non-abelian case, the fluctuation of the
"angular" component will increase rapidly with time while in the abelian case
it will not.


title: Tachyon Vortex

abstract:
  The property and gravitational field of global string of tachyon matter are
investigated in a four dimentional approximately cylindrically-symmetric
spacetime with a deficit angle. Especially, we give an exact solution of the
tachyon field in the flat spacetime background and we also find the solution of
the metric in the linearized approximation of gravity.


title: Efficiency of stripping mechanisms

abstract:
  There are several physical processes to remove gas from galaxies in clusters,
with subsequent starvation and star formation quenching: tidal interactions
between galaxies, or tidal stripping from the cluster potential itself,
interactions with the hot intra-cluster medium (ICM) through ram pressure,
turbulent or viscous stripping, or also outflows from star formation of nuclear
activity, We review the observational evidence for all processes, and numerical
simulations of galaxies in clusters which support the respective mechanisms.
This allows to compare their relative efficiencies, all along cluster
formation.


title: The age dependence of the Vega phenomenon: Observations

abstract:
  We study the time dependency of Vega-like excesses using infrared studies
obtained with the imaging photopolarimeter ISOPHOT on board of ISO. We review
the different studies published on this issue, and critically check and revise
ages and fractional luminosities in the different samples. The conclusions of
our study differ significantly from those obtained by other authors (e.g.
Holland et al. 1998; Spangler et al. 2001) who suggested that there is a global
power-law governing the amount of dust seen in debris disks as a function of
time. Our investigations lead us to conclude that (i) for stars at most ages, a
large spread in fractional luminosity occurs, but (ii) there are few very young
stars with intermediate or small excesses; (iii) the maximum excess seen in
stars of a given age is about a fractional luminosity of approximately 10^{-3},
independent of time; and (iv) Vega-like excess is more common in young stars
than in old stars.


title: Observing H2 Emission in Forming Galaxies

abstract:
  We study the H2 cooling emission of forming galaxies, and discuss their
observability using the future infrared facility SAFIR. Forming galaxies with
mass >10^11 Msun emit most of their gravitational energy liberated by
contraction in molecular hydrogen line radiation, although a large part of
thermal energy at virialization is radiated away by the H Ly alpha emission.
For more massive objects, the degree of heating due to dissipation of kinetic
energy is so great that the temperature does not drop below 10^4 K and the
gravitational energy is emitted mainly by the Ly alpha emission. Therefore, the
total H2 luminosity attains the peak value of about 10^42 ergs/s for forming
galaxies whose total mass 10^11 Msun. If these sources are situated at redshift
z=8, they can be detected by rotational lines of 0-0S(3) at 9.7 micron and
0-0S(1) at 17 micron by SAFIR. An efficient way to find such H2 emitters is to
look at the Ly alpha emitters, since the brightest H2 emitters are also
luminous in the Ly alpha emission.


title: High-Energy Emission from Pulsars: The Polar Cap Scenario

abstract:
  The study of pulsars in the three and a half decades since their discovery
has highlighted a handful of issues critical to their understanding. To date
there is no consensus on the physical mechanism for their radio radio emission,
despite a rapid increase in the observed population due to the Parkes
Multi-Beam survey and prospects for similar growth in the radio population
database in the near future. The small subset of pulsars that emit at X-ray to
gamma-ray wavelengths are critical to refining the pulsar paradigm since this
energy band (i) is where the vast majority of radiative luminosity is observed,
and (ii) is intimately connected to the pair winds that form the dominant mode
of energy deposition in the circum-pulsar environment. The most crucial point
of contention pertaining to the high energy astrophysics of pulsars is the
location of the acceleration region in their magnetospheres: is an outer gap
model or a polar cap scenario (or both) the most appropriate picture. Radiative
signatures provide the clues to this current enigma. This review focuses on
salient characteristics of the polar cap scenario; these form the basis for
discriminating observational diagnostics that should drive pulsars studies in
the GLAST era just three years away.


title: Type Ia supernovae in dense circumstellar gas

abstract:
  We propose a simple model for the bolometric light curve of type Ia supernova
exploding in a dense circumstellar (CS) envelope to describe the light curves
of supernovae 2002ic and 1997cy. The modeling shows that at the radius
$\sim7\times10^{15}$ cm the density of CS envelopes around both supernovae is
similar. The mass of the CS envelope around SN 1997cy is close to $5
M_{\odot}$, while the characteristic time of the ejection of this envelope does
not exceed 600 yr. We analyze two possible evolutionary scenarios which might
lead to the explosion of type Ia supernova inside a dense CS envelope:
accretion on CO white dwarf in the symbiotic binary and evolution of a single
star with the initial mass of about $8 M_{\odot}$. If the conjecture about the
explosion of type Ia supernova in a dense CS envelope is correct in the case of
SN 2002ic and SN 1997cy then the rapid loss of the red supergiant envelope and
the subsequent explosion of the CO white dwarf are synchronized by certain
mechanism. This mechanism might be related to the contraction of the white
dwarf as it approaches the Chandrasekhar limit. We show that formation of a
(super)Chandrasekhar mass due to the merger of a CO white dwarf and CO core of
a red supergiant with consequent explosion is unlikely, since it does not
provide the required synchronization of the rapid mass loss and explosion.


title: The Star Formation History in the Andromeda Halo

abstract:
  I present the preliminary results of a program to measure the star formation
history in the halo of the Andromeda galaxy. Using the Advanced Camera for
Surveys (ACS) on the Hubble Space Telescope, we obtained the deepest optical
images of the sky to date, in a field on the southeast minor axis of Andromeda,
51 arcmin (11 kpc) from the nucleus. The resulting color-magnitude diagram
(CMD) contains approximately 300,000 stars and extends more than 1.5 mag below
the main sequence turnoff, with 50% completeness at V=30.7 mag. We interpret
this CMD using comparisons to ACS observations of five Galactic globular
clusters through the same filters, and through chi-squared fitting to a
finely-spaced grid of calibrated stellar population models. We find evidence
for a major (approximately 30%) intermediate-age (6-8 Gyr) metal-rich ([Fe/H] >
-0.5) population in the Andromeda halo, along with a significant old metal-poor
population akin to that in the Milky Way halo. The large spread in ages
suggests that the Andromeda halo formed as a result of a more violent merging
history than that in our own Milky Way.


title: PSR J0609+2130: A disrupted binary pulsar?

abstract:
  We report the discovery and initial timing observations of a 55.7-ms pulsar,
J0609+2130, found during a 430-MHz drift-scan survey with the Arecibo radio
telescope. With a spin-down rate of $3.1 \times 10^{-19}$ s s$^{-1}$ and an
inferred surface dipole magnetic field of only $4.2 \times 10^{9}$ G,
J0609+2130 has very similar spin parameters to the isolated pulsar J2235+1506
found by Camilo, Nice & Taylor (1993). While the origin of these weakly
magnetized isolated neutron stars is not fully understood, one intriguing
possibility is that they are the remains of high-mass X-ray binary systems
which were disrupted by the supernova explosion of the secondary star.


title:
Testing the binary black hole paradigm through the Fe Kalpha line
  profile: application to 3C 273

abstract:
  We propose the study of long-term variations in the Fe Kalpha line profile as
a discriminator for binary black hole (BH) systems. The existence of a binary
BH in the center of an active galaxy will produce a particular signature in the
evolution of the line profile, as a result of disk precession. This signature
is a periodic variation of the position of the blue edge of the profile,
accompanied by periodic change of its intensity. We show that detection of the
former is clearly within the observational capabilities of planned X-ray
missions. Detecting a periodic variation of line profiles would provide the
first direct evidence for precessing discs in active galactic nuclei, as
opposed to the existing evidence supporting only the precession of jets. We
apply these ideas to 3C 273.


title:
Repeated Bifurcation of Relativistic Magnetic Pulse and Cosmic Gamma-Ray
  Bursts

abstract:
  The diverse and complex light curves of gamma-ray bursts (GRBs) remain an
outstanding astrophysical mystery. Here we report the results of
2-1/2-dimensional particle-in-cell (PIC) simulations of the relativistic
expansion of magnetized electron-positron plasmas. When the simulation is
carried to >150 light-crossing time of the initial plasma, the plasma pulse
reproduces many of the GRB features. Remarkably, the plasma pulse bifurcates
repeatedly, leading to a complex, multi-peak structure at late times,
resembling GRB profiles.


title: The Galactic Bar

abstract:
  Like the majority of spiral galaxies, the Milky Way contains a central
non-axisymmetric bar component. Our position in the Galactic plane renders it
rather hard to see, but also allows us to make measurements of the bar that are
completely unobtainable for any other system. This paper reviews the evidence
for a bar that can be gleaned from the many extensive surveys of both gas and
stars in the Milky Way. We introduce some simplified models to show how the
basic properties of the bar can be inferred in a reasonably robust manner
despite our unfavorable location, and how the complex geometry can be used to
our advantage to obtain a unique three-dimensional view of the bar. The
emerging picture of the Galactic bar is also placed in the broader context of
current attempts to understand how such structures form and evolve in spiral
galaxies.


title:
The Spectral Energy Distributions of Infant Super Star Clusters in
  Henize 2-10 from 7mm to 6cm

abstract:
  We present observations from our continuing studies of the earliest stages of
massive star cluster evolution. In this paper, radio observations from the Very
Large Array at 0.7cm, 1.3cm, 2cm, 3.6cm, and 6cm are used to map the radio
spectral energy distributions and model the physical properties of the
ultra-young embedded super star clusters in Henize 2-10. The 0.7cm flux
densities indicate that the young embedded star clusters that are powering the
radio detected ``ultradense HII regions'' (UDHIIs) have masses greater than
\~10^5 Msun. We model the radio spectral energy distributions as both constant
density HII regions and HII regions with power-law electron density gradients.
These models suggest the UDHIIs have radii ranging between ~2-4pc and average
electron densities of ~10^3-10^4 cm^-3 (with peak electron densities reaching
values of ~10^5-10^6 cm^-3). The pressures implied by these densities are
P/k_B~10^7-10^10 cm^-3 K, several orders of magnitude higher than typical
pressures in the Galactic ISM. The inferred HII masses in the UDHIIs are
\~2-8x10^3 Msun; these values are <5% of the embedded stellar masses, and
anonamously low when compared to optically visible young clusters. We suggest
that these low HII mass fractions may be a result of the extreme youth of these
objects.


title:
Electron Positron Capture Rates and Beta-Equilibrium Condition for
  Electron-Positron Plasma with Nucleons

abstract:
  The exact reaction rates of beta processes for all particles at arbitrary
degeneracy are derived, and an analytic beta-equilibrium condition
$\mu_n=\mu_p+2\mu_e$ for the hot electron-positron plasma with nucleons is
found, if the matter is transparent to neutrinos. This simple analytic formula
is valid only if electrons are nondegenerate, which is generally satisfied in
the hot electron-positron plasma. Therefore, it can be used to efficiently
determine the steady state of the hot matter with positrons.


title:
The convergence fluctuation of light by clusters of galaxies - a
  cosmological test using the second acoustic peak of the microwave background

abstract:
  The magnification of distant sources by mass clumps at lower ($z \leq 1$)
redshifts is calculated analytically. The clumps are initially assumed to be
galaxy group isothermal spheres with properties inferred from an extensive
survey. The average effect, which includes strong lensing, is exactly
counteracted by the beam divergence in between clumps (more precisely, the
average reciprocal magnification cancels the inverse Dyer-Roeder
demagnification). This conclusion is in fact independent of the matter density
function within each clump, and remains valid for arbitrary densities of matter
and dark energy. When tested against the CMB, a rather large lensing induced
{\it dispersion} in the angular size of the primary acoustic peaks of the TT
power spectrum is inconsistent with WMAP observations. The situation is
unchanged by the use of NFW profiles for the density distribution of groups.
Finally, our formulae are applied to an ensemble of NFW mass clumps or
isothermal spheres having the parameters of galaxy {\it clusters}. The acoustic
peak size dispersion remains unobservably large, and is also excluded by WMAP.
For galaxy groups, two possible ways of reconciling with the data are proposed,
both exploiting maximally the uncertainties in our knowledge of group
properties. The same escape routes are not available in the case of clusters,
however, because their properties are well understood. Here we have a more
robust conclusion: neither of the widely accepted models are good description
of clusters, or important elements of physics responsible for shaping zero
curvature space are missing from the standard cosmological model. When all the
effects are accrued, it is difficult to understand how WMAP could reveal no
evidence whatsoever of lensing by groups and clusters.


title: 870 micron observations of nearby 3CRR radio galaxies

abstract:
  We present submillimeter continuum observations at 870 microns of the cores
of low redshift 3CRR radio galaxies, observed at the Heinrich Hertz
Submillimeter Telescope. The cores are nearly flat spectrum between the radio
and submillimeter which implies that the submillimeter continuum is likely to
be synchrotron emission and not thermal emission from dust. The emitted power
from nuclei detected at optical wavelengths and in the X-rays is similar in the
submillimeter, optical and X-rays. The submillimeter to optical and X-ray power
ratios suggest that most of these sources resemble misdirected BL Lac type
objects with synchrotron emission peaking at low energies. However we find
three exceptions, the FR I galaxy 3C264 and the FR II galaxies 3C390.3 and
3C338 with high X-ray to submillimeter luminosity ratios. These three objects
are candidate high or intermediate energy peaked BL Lac type objects. With
additional infrared observations and from archival data, we compile spectral
energy distributions (SEDs) for a subset of these objects. The steep dips
observed near the optical wavelengths in many of these objects suggest that
extinction inhibits the detection and reduces the flux of optical continuum
core counterparts. High resolution near or mid-infrared imaging may provide
better measurements of the underlying synchrotron emission peak.


title:
Chandra Observations of Low Mass X-ray Binaries and Diffuse Gas in the
  Early-Type Galaxies NGC 4365 and NGC 4382 (M85)

abstract:
  (Abridged) We used the Chandra X-ray Observatory ACIS S3 to image the X-ray
faint elliptical galaxy NGC 4365 and lenticular galaxy NGC 4382. The
observations resolve much of the X-ray emission into 99 and 58 sources,
respectively, most of which are low-mass X-ray binaries (LMXBs) associated with
each of the galaxies. We identify 18 out of the 37 X-ray sources in a central
field in NGC 4365 with globular clusters. The luminosity functions of the
resolved sources for both galaxies are best fit with cutoff power-laws whose
cutoff luminosity is $\approx 0.9 - 3.1 \times 10^{39}$ ergs s$^{-1}$. These
luminosities are much larger than those previously measured for similar
galaxies; we do not find evidence for a break in the luminosity function at the
Eddington luminosity of a 1.4 $M_\odot$ neutron star. The spatial distributions
of the resolved sources for both galaxies are broader than the distribution of
optical stars. In both galaxies, a hard power-law model fits the summed
spectrum of all of the sources. The unresolved emission is best fit by the sum
of a soft mekal model representing emission from diffuse gas, and a hard
power-law, presumed to be from unresolved LMXBs. A standard beta model fits the
radial distribution of the diffuse gas in both galaxies. In the elliptical NGC
4365, the best-fit core radius is very small, while the S0 galaxy NGC 4382 has
a larger core radius. This may indicate that the gas in NGC 4382 is rotating
significantly.


title:
Hydrodynamic Simulation of Supernova Remnants Including Efficient
  Particle Acceleration

abstract:
  A number of supernova remnants (SNRs) show nonthermal X-rays assumed to be
synchrotron emission from shock accelerated TeV electrons. The existence of
these TeV electrons strongly suggests that the shocks in SNRs are sources of
galactic cosmic rays (CRs). In addition, there is convincing evidence from
broad-band studies of individual SNRs and elsewhere that the particle
acceleration process in SNRs can be efficient and nonlinear. If SNR shocks are
efficient particle accelerators, the production of CRs impacts the thermal
properties of the shock heated, X-ray emitting gas and the SNR evolution. We
report on a technique that couples nonlinear diffusive shock acceleration,
including the backreaction of the accelerated particles on the structure of the
forward and reverse shocks, with a hydrodynamic simulation of SNR evolution.
Compared to models which ignore CRs, the most important hydrodynamical effects
of placing a significant fraction of shock energy into CRs are larger shock
compression ratios and lower temperatures in the shocked gas. We compare our
results, which use an approximate description of the acceleration process, with
a more complete model where the full CR transport equations are solved (i.e.,
Berezhko et al., 2002), and find excellent agreement for the CR spectrum summed
over the SNR lifetime and the evolving shock compression ratio. The importance
of the coupling between particle acceleration and SNR dynamics for the
interpretation of broad-band continuum and thermal X-ray observations is
discussed.


title:
COMPASS: An Upper Limit on CMB Polarization at an Angular Scale of 20
  arc minutes

abstract:
  COMPASS is an on-axis 2.6 meter telescope coupled to a correlation
polarimeter operating at a wavelength of 1 cm. The entire instrument was built
specifically for CMB polarization studies. We report here on observations of
February 2001 - April 2001 using this system. We set an upper limit on E-mode
polarized anisotropies of 33.5 uK (95% confidence limit) in the l-range
200-600.


title:
A CS J=5-4 Mapping Survey Towards High-mass Star Forming Cores
  Associated with Water Masers

abstract:
  We have mapped 63 regions forming high-mass stars in CS J=5-4 using the CSO.
The CS peak position was observed in C34S J=5-4 towards 57 cores and in 13CS
J=5-4 towards the 9 brightest cores. The sample is a subset of a sample
originally selected toward water masers; the selection on maser sources should
favor sources in an early stage of evolution. The integrated intensity of CS
J=5-4 correlates very well with the dust continuum emission at 350 microns. The
distributions of size, virial mass, surface density, and luminosity are all
peaked with a few cores skewed towards much larger values than the mean. We
find a weak correlation between C34S linewidth and size, consistent with Dv ~
R^{0.3}. The linewidths are much higher than would be predicted by the usual
relations between linewidth and size determined from regions of lower mass.
These regions are very turbulent. The derived virial mass agrees within a
factor of 2 to 3 with mass estimates from dust emission at 350 microns after
corrections for the density structure are accounted for. The resulting
cumulative mass spectrum of cores above 1000 solar masses can be approximated
by a power law with a slope of about -0.9, steeper than that of clouds measured
with tracers of lower density gas and close to that for the total masses of
stars in OB associations. The median turbulent pressures are comparable to
those in UCHII regions, and the pressures at small radii are similar to those
in hypercompact-HII regions (P/k ~ 10^{10} K cm^{-3}). The filling factors for
dense gas are substantial, and the median abundance of CS is about 10^{-9}. The
ratio of bolometric luminosity to virial mass is much higher than the value
found for molecular clouds as a whole, and the correlation of luminosity with
mass is tighter. (Abridged).


title:
Transport of Ionizing Radiation in Terrestrial-like Exoplanet
  Atmospheres

abstract:
  (Abridged) The propagation of ionizing radiation through model atmospheres of
terrestrial-like exoplanets is studied for a large range of column densities
and incident photon energies using a Monte Carlo code we have developed to
treat Compton scattering and photoabsorption. Incident spectra from parent star
flares, supernovae, and gamma-ray bursts are modeled and compared to energetic
particles in importance. We find that terrestrial-like exoplanets with
atmospheres thinner than about 100 g cm^-2 transmit and reprocess a significant
fraction of incident gamma-rays, producing a characteristic, flat surficial
spectrum. Thick atmospheres (>~ 100 g cm^-2) efficiently block even gamma-rays,
but nearly all incident energy is redistributed into diffuse UV and visible
aurora-like emission, increasing the effective atmospheric transmission by many
orders of magnitude. Depending on the presence of molecular UV absorbers and
atmospheric thickness, up to 10% of the incident energy can reach the surface
as UV reemission. For the Earth, between 2 x 10^-3 and 4 x 10^-2 of the
incident flux reaches the ground in the biologically effective 200--320 nm
range, depending on O_2/O_3 shielding. Finally, we suggest that transient
atmospheric ionization layers can be frequently created at low altitudes. We
conclude that these events can produce frequent fluctuations in atmospheric
ionization levels and surficial UV fluxes on terrestrial-like planets.


title: Long-Term X-ray Spectral Variability in Seyfert 1 Galaxies

abstract:
  Direct time-resolved spectral fitting has been performed on continuous RXTE
monitoring of seven Seyfert 1 galaxies in order to study their broadband
spectral variability and Fe K alpha variability characteristics on time scales
of days to years. Variability in the Fe K alpha line is not detected in some
objects but is present in others, e.g., in NGC 3516, NGC 4151 and NGC 5548
there are systematic decreases in line flux by factors of ~2-5 over 3-4 years.
The Fe K alpha line varies less strongly than the broadband continuum, but,
like the continuum, exhibits stronger variability towards longer time scales.
Relatively less model-dependent broadband fractional variability amplitude
(Fvar) spectra also show weaker line variability compared to the continuum
variability. Comparable systematic long-term decreases in the line and
continuum are present in NGC 5548. Overall, however, there is no evidence for
correlated variability between the line and continuum, severely challenging
models in which the line tracks continuum variations modified only by a
light-travel time delay. Local effects such as the formation of an ionized skin
at the site of line emission may be relevant. The spectral fitting and Fvar
spectra both support spectral softening as continuum flux increases.


title: Evolution of rotation in binaries: physical processes

abstract:
  In this review, we describe the physical processes driving the dynamical
evolution of binary stars, namely the circularization of the orbit and the
synchronization of their spin and orbital rotation. We also discuss the
possible role of the elliptic instability which turns out to be an unavoidable
ingredient of the evolution of binary stars.


title: Grain Growth in the Dark Cloud L1251

abstract:
  We have performed optical imaging observations of the dark cloud L1251 at
multiple wavelengths, B, V, R, and I, using the 105 cm Schmidt telescope at the
Kiso Observatory, Japan. The cloud has a cometary shape with a dense "head"
showing star formation activity and a relatively diffuse "tail" without any
signs of star formation. We derived extinction maps of A_B and A_V with a star
count method, and also revealed the color excess (E_{B-V}, E_{V-R}, and
E_{V-I}) distributions. On the basis of the color excess measurements we
derived the distribution of the ratio of total to selective extinction R_V over
the cloud using an empirical relation between R_V and A_lambda/A_V reported by
Cardelli et al. In the tail of the cloud, R_V has a uniform value of ~3.2,
close to that often found in the diffuse interstellar medium (~3.1), while
higher values of R_V=4-6 are found in the dense head. Since R_V is closely
related to the size of dust grains, the high R_V-values are most likely to
represent the growth of dust grains in the dense star-forming head of the
cloud.


title: The Pisa Evolutionary Library

abstract:
  We supplement recent evolutionary computations of canonical stellar models
(i.e. with inefficient core overshooting) with Z=0.0002, 0.0004, 0.0006, 0.001,
0.004, 0.008 and suitable assumptions about the original He content.
Evolutionary results have been compared with observational data in order to
properly calibrate the efficiency of the surface convection. On this basis, we
follow the evolution of stellar models in the mass range 0.6 to 11 M$_{\odot}$
from the Main Sequence (MS) until C ignition or the onset of thermal pulses,
presenting cluster isochrones covering the range of ages from 20 Myr to 20 Gyr.
To allow a comparison with evolutionary investigations appeared in the recent
literature, we computed additional sets of models which take into account
moderate core overshooting during the H burning phase. Selected predictions
constraining the cluster ages are discussed, presenting a calibration of the
difference in magnitude between the luminous MS termination and the He burning
giants in terms of the cluster age. Both evolutionary tracks and isochrones
have been made available at the URL http://gipsy.cjb.net in the ``Pisa
Evolutionary Library'' directory.


title:
Measuring the Deviation from the Linear and Deterministic Bias through
  Cosmic Gravitational Lensing Effects

abstract:
  Since gravitational lensing effects directly probe inhomogeneities of dark
matter, lensing-galaxy cross-correlations can provide us important information
on the relation between dark matter and galaxy distributions, i.e., the bias.
In this paper, we propose a method to measure the stochasticity/nonlinearity of
the galaxy bias through correlation studies of the cosmic shear and galaxy
number fluctuations. Specifically, we employ the aperture mass statistics
$M_{ap}$ to describe the cosmic shear. We divide the foreground galaxy redshift
$z_f<z_s$ into several bins, where $z_s$ is the redshift of the source
galaxies, and calculate the quantity $<M_{ap}N_g(z_f)>^2/< N_g^2(z_f)>$ for
each redshift bin. Then the ratio of the summation of $<M_{ap}N_g(z_f)>^2/<
N_g^2(z_f)>$ over the bins to $<M_{ap}^2>$ gives a measure of the
nonlinear/stochastic bias. Here $N_g(z_f)$ is the projected surface number
density fluctuation of foreground galaxies at redshift $z_f$, and $M_{ap}$ is
the aperture mass from the cosmic-shear analysis. We estimate that for a
moderately deep weak-lensing survey with $z_s=1$, source galaxy surface number
density $n_b=30 \hbox {gal}/\hbox {arcmin}^2$ and a survey area of $25 \hbox
{deg}^2$, the effective $r$-parameter that represents the deviation from the
linear and deterministic bias is detectable in the angular range of 1'-10' if
$|r-1|\gsim 10%$. For shallow, wide surveys such as the Sloan Digital Sky
Survey with $z_s=0.5$, $n_b=5 \hbox {gal}/\hbox {arcmin}^2$, and a survey area
of $10^4 \hbox {deg}^2$, a 10% detection of $r$ is possible over the angular
range $1'-100'$.


title:
Modeling the NeIX Triplet Spectral Region of Capella with the Chandra
  and XMM-Newton Gratings

abstract:
  High resolution X-ray spectroscopy with the diffraction gratings of Chandra
and XMM-Newton offers new chances to study a large variety of stellar coronal
phenomena. A popular X-ray calibration target is Capella, which has been
observed with all gratings with significant exposure times. We gathered
together all available data of the HETGS (155ks), LETGS (219ks), and RGS (53ks)
for comparative analysis focusing on the NeIX triplet at around 13.5A, a region
that is severely blended by strong iron lines. We identify 18 emission lines in
this region of the HEG spectrum, including many from FeXIX, and find good
agreement with predictions from a theoretical model constructed using the
Astrophysical Plasma Emission Code (APEC). The model uses an emission measure
distribution derived from FeXV to FeXXIV lines. While these 18 emission lines
cannot be isolated in the LETGS or RGS spectra, their wavelengths and fluxes as
measured with HEG are consistent with the lower resolution spectra. In the
Capella model for HEG, the weak intercombination line of NeIX is significantly
blended by iron lines, which contribute about half the flux. After accounting
for blending in the He-like diagnostic lines, we find the density to be
consistent with the low density limit (n_e<2 10^10 cm^-3); however, the
electron temperature indicated by the NeIX G-ratio is surprisingly low (~2MK)
compared with the peak of the emission measure distribution (~6MK). Models show
that the NeIX triplet is less blended in cooler plasmas and in plasmas with an
enhanced neon-to-iron abundance ratio.


title: An HST Morphological Survey of Faint EROs

abstract:
  We present the results from a survey for Extremely Red Objects (EROs) in
deep, high resolution optical images taken from the Hubble Space Telescope
(HST) Medium Deep Survey. We have surveyed 35 deep F814W HST/WFPC2 fields in
the near-infrared to a typical depth of K~20. From a total area of 206 arcmin^2
and to a limit of K=20.0 we identify 224 EROs ((1.14+/-0.08) arcmin^-2) with
(I_{814}-K)=>4.0 and 83 ((0.41+/-0.05) arcmin^-2) with (I_{814}-K)=>5.0. We
find that the slope of the number counts of the (I_{814}-K)=>4.0 EROs flattens
beyond K~19, in line with results from previous surveys, and the typical
colours of the EROs become redder beyond the break magnitude. We
morphologically classify our ERO sample using visual and quantitative schemes
and find that 35% of our sample exhibit clear disk components, 15% are
disturbed or irregular, a further 30% are either spheroidal or compact and the
remaining 20% are unclassifiable. Using a quantitative measure of morphology,
we find that the ERO morphological distribution evolves across the break in
their counts, such that low concentration (disk-like) galaxies decline. We
relate the morphological and colour information for our EROs and conclude that
those EROs morphologically classified as bulges do indeed possess SEDs
consistent with passive stellar populations; while EROs with dusty star-forming
SEDs are mostly associated with disk-like and peculiar galaxies. However, ~30%
of disk EROs reside in the passive region of I/J/K colour-colour space. These
could be either genuinely passive systems, lower redshift contaminants to the
high-z ERO population, or systems with composite star-forming and passive SEDs.


title:
Chandra X-Ray Spectral Analysis of Cooling Flow Clusters, 2A 0335+096
  and Abell 2199

abstract:
  We report on a spatially resolved analysis of Chandra X-ray data on a nearby
typical cooling flow cluster of galaxies 2A 0335+096, together with A 2199 for
a comparison. As recently found in the cores of other clusters, the temperature
around the central part of 2A 0335+096 is 1.3--1.5 keV, which is higher than
that inferred from the cooling flow picture. Furthermore, the absorption column
density is almost constant against the radius in 2A 0335+096; there is no
evidence of excess absorption up to 200--250 kpc. This indicates that no
significant amount of cold material, which has cooled down, is present. These
properties are similar to those of A 2199. Since the cooling time in the
central part is much shorter than the age of the clusters, a heating mechanism,
which weakens the effect of radiative cooling, is expected to be present in the
central part of both clusters of galaxies. Both 2A 0335+096 and A 2199 have
radio jets associated with their cD galaxy. We discuss the possibility of
heating processes caused by these radio jets by considering the thermal
conduction and the sound velocity together with the observed disturbance of the
ICM temperature and density. We conclude that the observed radio jets can
produce local heating and/or cooling, but do not sufficiently reduce the
overall radiative cooling. This implies that much more violent jets, whose
emission has now decayed, heated up the cooling gas $>10^9$ years ago.


title: Mass segregation in the young open cluster NGC 2547

abstract:
  We present a study of mass segregation of the young (20-35 Myr isochronal
age), open cluster NGC 2547. We find good evidence that mass segregation exists
in NGC 2547 down to 3 Msun, and weak evidence for mass segregation down to 1
Msun. Theoretical models of an initially unsegregated model of NGC 2547 using
the NBODY2 code show weaker mass segregation, implying that at least some of
the observed mass segregation has a primordial origin. We also report the
discovery of three possible escaped cluster members, which share the proper
motion and colours of the cluster, but lie nearly a degree from the cluster
centre.


title: Solar flare electron acceleration: comparing theories and observations

abstract:
  A popular scenario for electron acceleration in solar flares is transit-time
damping of low-frequency MHD waves excited by reconnection and its outflows.
The scenario requires several processes in sequence to yield energetic
electrons of the observed large number. Until now there was very little
evidence for this scenario, as it is even not clear where the flare energy is
released. RHESSI measurements of bremsstrahlung by non-thermal flare electrons
yield energy estimates as well as the position where the energy is deposited.
Thus quantitative measurements can be put into the frame of the global magnetic
field configuration as seen in coronal EUV line observations. We present RHESSI
observations combined with TRACE data that suggest primary energy inputs mostly
into electron acceleration and to a minor fraction into coronal heating and
primary motion. The more sensitive and lower energy X-ray observations by
RHESSI have found also small events (C class) at the time of the acceleration
of electron beams exciting meter wave Type III bursts. However, not all RHESSI
flares involve Type III radio emissions. The association of other decimeter
radio emissions, such as narrowband spikes and pulsations, with X-rays is
summarized in view of electron acceleration


title:
Fine Structure of the Thermal and Non-Thermal X-Rays in the SN 1006
  Shell

abstract:
  The North Eastern shell of SN 1006 is the most probable acceleration site of
high energy electrons (up to about 100 TeV) with the Fermi acceleration
mechanism at the shock front. We resolved non-thermal filaments from thermal
emission in the shell with the excellent spatial resolution of Chandra. The
non-thermal filaments seem thin sheets with the scales of about 1 arcsec (0.01
pc) and about 20 arcsec (0.19 pc) upstream and downstream of the shock,
respectively. In a simple diffusive shock acceleration (DSA) model with the
magnetic field parallel to the shock normal, the downstream region should have
a highly disordered magnetic field of 30-40 micro G. The width at the upstream
side is extremely small, comparable to the gyro-radius of the maximum energy
electrons. This result might imply that the possible scenario is not the
conventional diffusive shock acceleration with a parallel magnetic field but
that with a nearly perpendicular field or electron shock surfing acceleration.


title: Micro-events in the active and quiet solar corona

abstract:
  The content of hot material in the corona is not constant. Soft X-ray and
high-temperature EUV line observations show that new material, apparently
heated and evaporated from the chromosphere, is frequently injected into the
corona both in active and quiet regions. Active regions are found to exhibit
transient brightenings, termed here microflares, due to such enhancements in
emission measure. They appear at a rate of up to 10 per hour in RHESSI
observations of 3--15 keV X-rays, occurring even during the periods of lowest
solar activity so far in the mission. The RHESSI observations combined with
measurements at other wavelengths yield estimates of the energy input into the
corona. These observations suggest that the models for coronal heating must be
complemented with respect to continuous replenishing the lower corona by
chromospheric material heated to coronal temperatures. The observed
micro-events are secondary phenomena and do not represent the primary energy
release, nor its total amount. Nevertheless, they are an interesting source of
information on the heating process(es) of the corona. The micro-events are
compared to events in quiet regions, termed here nanoflares, which seem to be a
different population, well separated in temperature and emission measure from
microflares.


title: A New Family of Planets ? "Ocean Planets"

abstract:
  A new family of planets is considered which is between rochy terrestrial
planets and gaseous giant ones: "Ocean-Planets". We present the possible
formation, composition and internal models of these putative planets, including
that of their ocean, as well as their possible Exobiology interest. These
planets should be detectable by planet detection missions such as Eddington and
Kepler, and possibly COROT (lauch scheduled in 2006). They would be ideal
targets for spectroscopic missions such as Darwin/TPF.


title: A Black Hole Life Preserver

abstract:
  Since no one lives forever, all a life preserver can really do is prolong
life for longer than would have otherwise been the case. With this rather
limited definition in mind we explore in this paper whether in principle you
can take a life preserver with you to protect you (for a while at least)
against the tidal forces encountered on a trip inside a black hole.


title: Bare Quark Stars or Naked Neutron Stars ? The Case of RX J1856.5-3754

abstract:
  In a cool neutron star (T < 1.e6 K) endowed with a rather high magnetic field
(B > 1.e13 G), a phase transition may occur in the outermost layers. As a
consequence the neutron star becomes `bare', i.e. no gaseous atmosphere sits on
the top of the crust. The surface of a cooling, bare neutron star does not
necessarily emit a blackbody spectrum because the emissivity is strongly
suppressed at energies below the electron plasma frequency, omega_p. Since
omega_p ~ 1 keV under the conditions typical of the denseelectron gas in the
condensate, the emission from a T ~ 100 eV bare neutron star will be
substantially depressed with respect to that of a perfect Planckian radiator at
most energies. Here we present a detailed analysis of the emission properties
of a bare neutron star. In particular, we derive the surface emissivity for a
Fe composition in a range of magnetic fields and temperatures representative of
cooling isolated neutron stars, like RX J1856.5-3754. We find that the emitted
spectrum is strongly dependent on the electron conductivity in the solid
surface layers. In the cold electron gas approximation (no electron-lattice
interactions), the spectrum turns out to be a featureless depressed blackbody
in the 0.1-2 keV band with a steeper low-energy distribution. When damping
effects due to collisions between electrons and the ion lattice (mainly due to
electron-phonon interactions) are accounted for, the spectrum is more depressed
depending on the magnetic field strength. Details of the emitted spectrum are
found, however, to be strongly dependent of the assumed treatment of the
transition from the external vacuum to the metallic surface. The implications
of out results to RX J1856.5-3754 and other isolated neutron stars are
discussed.


title:
Evolution of the Nuclear Accretion Disk Emission in NGC 1097: Getting
  Closer to the Black Hole

abstract:
  We study the evolution of the broad, double-peaked Halpha emission-line
profile of the LINER/Seyfert 1 nucleus of NGC 1097, using 24 spectra obtained
over a time span of 11 yrs - from 1991 Nov. through 2002 Oct. While in the
first 5 yrs the main variation was in the relative intensity of the blue and
red peaks, in the last years we have also observed an increasing separation
between the two peaks, at the same time as the integrated flux in the broad
line has decreased. We propose a scenario in which the emission originates in
an asymmetric accretion disk around a supermassive black hole, whose source of
ionization is getting dimmer, causing the region of maximum emission to come
closer to the center (and thus to regions of higher projected velocity). We use
the observations to constrain the evolution of the accretion disk emission and
to evaluate two models: the elliptical disk model previously found to reproduce
the observations from 1991 to 1996 and a model of a circular disk with a single
spiral arm. We favor the latter, because the whole set of data is consistent
with a monotonic precession of the spiral pattern, which has completed almost
two revolutions since 1991. The precession period implies a black hole mass of
approximately 5x10^7 solar masses. Finally, we have found tentative evidence of
the emergence of an accretion disk wind, which we hope to explore further with
future observations.


title:
The three-point correlation function of cosmic shear. II: Relation to
  the bispectrum of the projected mass density and generalized third-order
  aperture measures

abstract:
  We study the relation of the three-point cosmic shear statistics to the
third-order statistical properties of the underlying convergence, expressed in
terms of its bispectrum. Explicit relations for the natural components of the
shear three-point correlation function in terms of the bispectrum are derived.
The behavior of the correlation function under parity transformation is
obtained and found to agree with previous results. We find that in contrast to
the two-point shear correlation function, the three-point function at a given
angular scale \theta is not affected by power in the bispectrum on much larger
scales. These relations are then inverted to obtain the bispectrum in terms of
the three-point shear correlator; two different expressions, corresponding to
different natural components of the shear correlator, are obtained and can be
used to separate E and B-mode shear contributions. These relations allow us to
explicitly show that correlations containing an odd power of B-mode shear
vanish for parity-symmetric fields. Generalizing a recent result by Jarvis et
al., we derive expressions for the third-order aperture measures, employing
multiple angular scales, in terms of the (natural components of the)
three-point shear correlator and show that they contain essentially all the
information about the underlying bispectrum. We discuss the many useful
features these (generalized) aperture measures have that makes them convenient
for future analyses of the skewness of the cosmic shear field (and any other
polar field, such as the polarization of the Cosmic Microwave Background).
(Abridged)


title:
2MASSJ0516288+260738: Discovery of the first eclipsing late K + Brown
  dwarf system?

abstract:
  We report the discovery of a new eclipsing system less than one arcminute
south of the pulsating DB white dwarf KUV 05134+2605. The object could be
identified with the point source 2MASSJ0516288+260738 published by the Two
Micron All Sky Survey. We present and discuss the first light curves as well as
some additional colour and spectral information. The eclipse period of the
system is 1.29d, and, assuming this to be identical to the orbital period, the
best light curve solution yields a mass ratio of m2/m1=0.11, a radius ratio of
r2/r1~1 and an inclination of 74 deg. The spectral anaylsis results in a
Teff=4200K for the primary. On this basis, we suggest that the new system
probably consists of a late K + Brown dwarf (which would imply a system
considerably younger than ~0.01 Gyr to have r2/r1~1), and outline possible
future observations.


title:
A Search for Very Extended Ionized Gas in Nearby Starburst and Active
  Galaxies

abstract:
  We report the results from a pilot study of 10 nearby starburst and active
galaxies conducted with the Taurus Tunable Filter (TTF) on the Anglo-Australian
and William Herschel Telescopes. The main purpose of this imaging survey is to
search for warm emission-line gas on the outskirts (galactocentric distances R
> 10 kpc) of galaxies to provide direct constraints on the size and geometry of
the ``zone of influence'' of these galaxies on their environment. Gaseous
complexes or filaments larger than ~ 20 kpc are discovered or confirmed in six
of the galaxies in the sample (NGC 1068, NGC 1482, NGC 4388, NGC 6240, NGC
7213, and MR 2251-178). Slightly smaller structures are seen for the first time
in the ionization cones and galactic winds of NGC 1365, NGC 1705, Circinus
galaxy, and ESO484-G036. The TTF data are combined with new optical long-slit
spectra as well as published and archived radio and X-ray maps to constrain the
origin and source of ionization of these filaments. A broad range of phenomena
is observed, including large-scale ionization cones and galactic winds, tidal
interaction, and ram-pressure stripping by an intracluster medium. The source
of ionization in this gas ranges from shock ionization to photoionization by
the central AGN or in-situ hot young stars. The sample is too small to draw
statistically meaningful conclusions about the extent and properties of the
warm ionized medium on large scale and its relevance to galaxy formation and
evolution. The next generation of tunable filters on large telescopes promises
to improve the sensitivity to faint emission-line fluxes at least tenfold and
allow systematic surveys of a large sample of emission-line galaxies.


title: A Concept for a High-Energy Gamma-ray Polarimeter

abstract:
  We present a concept for an imaging gamma-ray polarimeter operating from ~50
MeV to ~1 GeV. Such an instrument would be valuable for the study of
high-energy pulsars, active galactic nuclei, supernova remnants, and gamma-ray
bursts. The concept makes use of pixelized gas micro-well detectors, under
development at Goddard Space Flight Center, to record the electron-positron
tracks from pair-production events in a large gas volume. Pixelized micro-well
detectors have the potential to form large-volume 3-D track imagers with ~100
micron (rms) position resolution at moderate cost. The combination of high
spatial resolution and a continuous low-density gas medium permits many
thousands of measurements per radiation length, allowing the particle tracks to
be imaged accurately before multiple scattering masks their original
directions. The polarization of the incoming radiation may then be determined
from the azimuthal distribution of the electron-positron pairs. We have
performed Geant4 simulations of these processes to estimate the polarization
sensitivity of a simple telescope geometry at 100 MeV.


title: Composition of the Chandra ACIS contaminant

abstract:
  The Advanced CCD Imaging Spectrometer (ACIS) on the Chandra X-ray Observatory
is suffering a gradual loss of low energy sensitivity due to a buildup of a
contaminant. High resolution spectra of bright astrophysical sources using the
Chandra Low Energy Transmission Grating Spectrometer (LETGS) have been analyzed
in order to determine the nature of the contaminant by measuring the absorption
edges. The dominant element in the contaminant is carbon. Edges due to oxygen
and fluorine are also detectable. Excluding H, we find that C, O, and F
comprise >80%, 7%, and 7% of the contaminant by number, respectively. Nitrogen
is less than 3% of the contaminant. We will assess various candidates for the
contaminating material and investigate the growth of the layer with time. For
example, the detailed structure of the C-K absorption edge provides information
about the bonding structure of the compound, eliminating aromatic hydrocarbons
as the contaminating material.


title:
Meeting the Cool Neighbours, VI: A search for nearby ultracool dwarfs in
  the Galactic Plane

abstract:
  Surveys for nearby low-luminosity dwarfs tend to avoid the crowded regions of
the Galactic Plane. We have devised near-infrared colour-magnitude and
colour-colour selection criteria designed to identify late-type M and
early-type L dwarfs within 12 parsecs of the Sun. We use those criteria to
search for candidates within the regions of the Galactic Plane (|b| < 10^o)
covered by the Second Incremental Release of data from the Two-Micron All Sky
Survey. Detailed inspection of the available photographic images of the
resulting 1299 candidates confirms only two as ultracool dwarfs. Both are known
proper motion stars, identified in the recent survey by Lepine et al (2002).
Despite the low numbers, the inferred surface density is consistent with
comparable surveys at higher latitudes. We discuss the implications for the
luminosity function, and consider means of improving the efficiency and scope
of photometric surveys in the Plane.


title: Recent Progress on a New Geometric Distance to NGC 4258

abstract:
  We report on our ongoing, high-resolution study of H2O masers in the
innermost parsec of NGC 4258. Over thirty epochs of VLBA and VLA data, taken
over six years, are being used to monitor the velocities, accelerations,
positions and proper motions of water masers rotating in a warped, Keplerian
disk about a supermassive central object. Our extensive monitoring results in
an improved accuracy in the distance determination to this galaxy (i) via a
reduction in experimental random errors due to a longer time-baseline than in
previous work; and (ii) via a better modeling of sources of systematic error,
such as disk eccentricity. These data can therefore yield an extremely accurate
geometric distance to NGC 4258.


title:
X-ray Sources with Periodic Variability in a Deep Chandra Image of the
  Galactic Center

abstract:
  We report the discovery of eight X-ray sources with periodic variability in
487 ks of observations of the Galactic center with Chandra. The sources are
identified from a sample of 285 objects detected with 100-4200 net counts.
Their periods range from 300 s to 4.5 h with amplitudes between 40% and 70%
rms. They have luminosities of (1 - 5) \times 10^{32} erg/sec (2--8 keV at 8
kpc). The spectra of seven of the eight sources are consistent with Gamma = 0
power laws absorbed by gas and dust with a column density equal to or higher
than that toward the Galactic Center (6 times 10^{22} cm^{-2}). Four of these
sources also exhibit emission lines near 6.7 keV from He-like Fe, with
equivalent widths of 600-1000 eV. These properties are consistent with both
magnetically accreting cataclysmic variables and wind-accreting neutron stars
in high-mass X-ray binaries. The eighth source has an absorbing column of 5
\times 10^{21} cm^{-2} that places it in the foreground. Its spectrum is
consistent with either a Gamma = 1.4 power law or kT = 25 keV bremsstrahlung
emission. Its period-folded flux profile clearly identifies it as an eclipsing
polar. We place an approximate upper limit of i^\prime > 23 magnitude on the
optical counterpart to this source using a 5 min exposure obtained with the
MagIC camera on the Clay telescope (Magellan II) at Las Campanas.


title: Critical Magnetic Prandtl Number for Small-Scale Dynamo

abstract:
  We report a series of numerical simulations showing that the critical
magnetic Reynolds number Rm_c for the nonhelical small-scale dynamo depends on
the Reynolds number Re. Namely, the dynamo is shut down if the magnetic Prandtl
number Pr=Rm/Re is less than some critical value Pr_c<1 even for Rm for which
dynamo exists at Pr>=1. We argue that, in the limit of Re->infinity, a finite
Pr_c may exist. The second possibility is that Pr_c->0 as Re->infinity, while
Rm_c tends to a very large constant value inaccessible at current resolutions.
If there is a finite Pr_c, the dynamo is sustainable only if magnetic fields
can exist at scales smaller than the flow scale, i.e., it is always effectively
a large-Pr dynamo. If there is a finite Rm_c, our results provide a lower
bound: Rm_c<220 for Pr<=1/8. This is larger than Rm in many planets and in all
liquid-metal experiments.

categories: astro-ph nlin.CD physics.flu-dyn physics.geo-ph


title: The chemical composition of a mild barium star HD202109

abstract:
  We present the result of chemical abundances of a mild barium star HD202109
(zeta Cyg) determined from the analysis of spectrum obtained by using a 2-m
telescope at the Peak Terskol Observatory and a high-resolution spectrometer
with R=80,000, signal to noise ratio >100. We also present the atmospheric
parameters of the star determined by using various methods including iron-line
abundance analysis. For line identifications, we use whole-range synthetic
spectra computed by using the Kurucz database and the latest lists of spectral
lines. Among the determined abundances of 51 elements, those of P, S, K, Cu,
Zn, Ge, Rb, Sr, Nb, Mo, Ru, Rh, Pd, In, Sm, Gd, Tb, Dy, Er, Tm, Hf, Os, Ir, Pt,
Tl, and Pb have not been previously known. Under the assumption that the
overabundance pattern of Ba stars is due to wind-accretion process, adding
information of more element abundances enables one to show that the heavy
element overabundances of HD202109 can be explained with the wind accretion
scenario model.


title: Gravitational lensing by globular clusters and Arp objects

abstract:
  We try to explain quasar-galaxy associations by gravitational lensing by
globular clusters, located in the halos of foreground galaxies. We propose
observational test for verification of this hypothesis. We processed
SUPERCOSMOS sky survey and found overdensities of star-like sources with zero
proper motions in the vicinities of foreground galaxies from CfA3 catalog. We
show mean effect for galaxies with different redshifts. Two effects can explain
observational data - these are lensing by globular clusters and lensing by
dwarf galaxies. We made CCD 3-color photometry with 2.0-1.2 meter telescopes to
select extremely lensed objects around several galaxies for spectroscopic
observations.


title:
Stellar abundance patterns. What is the possible level of completeness
  today ?

abstract:
  We discuss the way of increasing of the number of chemical elements,
investigated in stellar spectra. We can reach it by using spectrum synthesis
method, new atomic data and observation of stellar spectra with resolution
comparable to solar spectral atlases. We show two examples of this kind
researches. The first is the implementation of new atomic data to well known
Przybylski's star. We show that the number of spectral lines, which can be
identificated in the spectrum of this star can be significantly higher. The
second example is the investigation of zeta Cyg. We found the abundances of 51
elements in the atmosphere of this mild barium star.


title: On the formation of massive stellar clusters

abstract:
  Here we model a star forming factory in which the continuous creation of
stars results in a highly concentrated, massive (globular cluster-like) stellar
system. We show that under very general conditions a large-scale gravitational
instability in the ISM, which triggers the collapse of a massive cloud, leads
with the aid of a spontaneous first generation of massive stars, to a standing,
small-radius, cold and dense shell. Eventually, as more of the collapsing
matter is processed and incorporated, the shell becomes gravitationally
unstable and begins to fragment, allowing the formation of new stars, while
keeping its location. This is due to a detailed balance established between the
ram pressure from the collapsing cloud which, together with the gravitational
force exerted on the shell by the forming cluster, acts against the mechanical
energy deposited by the collection of new stars. We analyze the mass spectrum
of fragments that result from the continuous fragmentation of the standing
shell and show that its shape is well approximated at the high mass end by a
power law with slope -2.25, very close to the value that fits the universal
IMF. The self-contamination resultant from the continuous generation of stars
is shown to lead to a large metal spread in massive ($\sim$ 10$^6$ M$_\odot$)
clusters, while clusters with a mass similar to 10$^5$ M$_\odot$ or smaller,
simply reflect the initial metalicity of the collapsing cloud. This is in good
agreement with the data available for globular clusters in the Galaxy.


title: HST multiband photometry of the globular cluster NGC 6388

abstract:
  We present color-magnitude diagrams (CMD) of the globular cluster NGC 6388
based on HST multiband photometry (F255W, F336W, F439W, F555W). In this paper
we focus our attention on the peculiar horizontal branch of this cluster. After
a careful reddening correction, we fitted the observed CMD with theoretical
models. For the first time we demonstrated that the HB of this very metal rich
globular cluster extends beyond Te > 30.000 K, showing clear evidence of a
population of blue hook (D'Cruz et al.2000, Brown et al. 2001) stars. Moreover,
we could demonstrate that the HB tilt (slope) is not a reddening effect and is
present in all the photometric bands.


title: Black Holes, Galaxy Formation, and the M_BH-sigma Relation

abstract:
  Recent X-ray observations of intense high-speed outflows in quasars suggest
that supercritical accretion on to the central black hole may have an important
effect on a host galaxy. I revisit some ideas of Silk and Rees, and assume such
flows occur in the final stages of building up the black hole mass. It is now
possible to model explicitly the interaction between the outflow and the host
galaxy. This is found to resemble a momentum-driven stellar wind bubble,
implying a relation M_BH = (f_g kappa/2 pi G^2) sigma^4 = 1.5 10^8 sigma_200^4
Msun between black hole mass and bulge velocity dispersion (f_g = gas fraction
of total matter density, kappa = electron scattering opacity), without free
parameters. This is remarkably close to the observed relation in both slope and
normalization.
  This result suggests that the central black holes in galaxies gain most of
their mass in phases of super-Eddington accretion, which are presumably
obscured or at high redshift. Observed super-Eddington quasars are apparently
late in growing their black hole masses.


title: Comments on "Measuring the Gravity Speed by VLBI"

abstract:
  Einstein gravity with extra dimensions or alternative gravity theories might
suggest that the gravity propagation speed can be different from the light
speed. Such a difference may play a vital role in the primordial universe. In
recent, Kopeikin and Fomalont claimed the first measurement of the gravity
speed by VLBI. However, the measurement has no relevance with the speed of
gravity as I had shown before the observation was done. It seems that our
conclusion has been established well by re-examining recent papers with great
care.


title: Rosseland and Planck Mean Opacities for Protoplanetary Discs

abstract:
  In this paper, we present mean gas and dust opacities relevant to the
physical conditions typical of protoplanetary discs. As the principal absorber
for temperatures below ~1,500 K, we consider spherical and aggregate dust
particles of various sizes, chemical structure, and porosity, consisting of
ice, organics, troilite, silicates, and iron. For higher temperatures, ions,
atoms, molecules, and electrons are included as the main opacity sources.
Rosseland and Planck mean opacities are calculated for temperatures between 5 K
and 10,000 K and gas densities ranging from 10^{-18} g/ccm to 10^{-7} g/ccm.
The dependence on the adopted model of dust grains is investigated. We compare
our results with recent opacity tables and show how different opacity models
affect the calculated hydrodynamical structure of accretion discs.


title: Near-IR spectroscopy of PKS1549-79: a proto-quasar revealed?

abstract:
  We present a near-IR spectrum of the nearby radio galaxy PKS1549-79 (z=0153).
These data were taken with the aim of testing the idea that this object
contains a quasar nucleus that is moderately extinguished, despite evidence
that its radio jet points close to our line-of-sight. We detect broad Paschen
Alpha emission (FWHM ~1745 km/s), relatively bright continuum emission, and a
continuum slope consistent with a reddened quasar spectrum (3.1 < Av < 7.3),
all emitted by an unresolved point source. Therefore we conclude that we have,
indeed, detected a hidden quasar nucleus in PKS1549-79. Combined with previous
results, these observations are consistent with the idea that PKS1549-79 is a
young radio source in which the cocoon of debric left over from the triggering
events has not yet been swept aside by circumnuclear outflows.


title:
INTEGRAL Spectrometer SPI's GRB detection capabilities. GRBs detected
  inside SPI's FoV and with the anticoincidence system ACS

abstract:
  The spectrometer SPI, one of the two main instruments of the INTEGRAL
spacecraft, offers significant gamma-ray burst detection capabilities. In its
35 deg (full width) field of view SPI is able to localise gamma-ray bursts at a
mean rate of ~ 0.8/month. With its large anticoincidence shield of 512 kg of
BGO crystals SPI is able to detect gamma-ray bursts quasi omni-directionally
with a very high sensitivity. Burst alerts of the anticoincidence shield are
distributed by the INTEGRAL Burst Alert System. In the first 8 months of the
mission about 0.8/day gamma-ray burst candidates and 0.3/day gamma-ray burst
positions were obtained with the anticoincidence shield by interplanetary
network triangulations with other spacecrafts.


title: The State of pulsar theory

abstract:
  I summarize the status of pulsar theory, now 35 years after their discovery.
Although progress has been made in understanding the relevant processes
involved, there are several widely held misconceptions that are inhibiting
further advances. These include the idea that plasma ``must'' be accelerated
from the magnetic polar caps (the basis for the ``Hollow Cone Model'') and the
idea that winds would be driven away by centrifugal forces, with large
amplitude electromagnetic waves playing no role whatsoever. However, recent
theoretical work is converging on a picture that closely resembles the latest
HST and CHANDRA images, providing hope for the future. No less than 3 groups
have recently confirmed the early Krause-Polstorff-Michel simulations showing
that the fundamental plasma distribution around a rotating neutron star
consists of two polar domes and an equatorial torus of trapped nonneutral
plasma of opposite sign charges. Unless a lot of new physics can be added, this
distribution renders the Goldreich-Julian model irrelevant (i.e., along with
most of the theoretical publications over the last 33 years).


title: Dwarf Dark Matter Halos

abstract:
  We study properties of dark matter halos at high redshifts z=2-10 for a vast
range of masses with the emphasis on dwarf halos with masses 10^7-10^9 Msun/h.
We find that the density profiles of relaxed dwarf halos are well fitted by the
NFW profile and do not have cores. We compute the halo mass function and the
halo spin parameter distribution and find that the former is very well
reproduced by the Sheth & Tormen model while the latter is well fitted by a
lognormal distribution with lambda_0 = 0.042 and sigma_lambda = 0.63. We
estimate the distribution of concentrations for halos in mass range that covers
six orders of magnitude from 10^7 Msun/h to 10^13} Msun/h, and find that the
data are well reproduced by the model of Bullock et al. The extrapolation of
our results to z = 0 predicts that present-day isolated dwarf halos should have
a very large median concentration of ~ 35. We measure the subhalo circular
velocity functions for halos with masses that range from 4.6 x 10^9 Msun/h to
10^13 Msun/h and find that they are similar when normalized to the circular
velocity of the parent halo. Dwarf halos studied in this paper are many orders
of magnitude smaller than well-studied cluster- and Milky Way-sized halos. Yet,
in all respects the dwarfs are just down-scaled versions of the large halos.
They are cuspy and, as expected, more concentrated. They have the same spin
parameter distribution and follow the same mass function that was measured for
large halos.


title:
Integral results on GRB030320: a long gamma-ray burst detected at the
  edge of the field of view

abstract:
  GRB030320 is the 5th Gamma-ray burst (GRB) detected by INTEGRAL in the field
of view (FoV). It is so far the GRB with the largest off-axis angle with
respect to the INTEGRAL pointing direction, near to the edge of the FoV of both
main instruments, IBIS and SPI. Nevertheless, it was possible to determine its
position and to extract spectra and fluxes. The GRB nature of the event was
confirmed by an IPN triangulation. It is a ~ 60 s long GRB with two prominent
peaks separated by ~ 35 s. The spectral shape of the GRB is best represented by
a single power law with a photon index Gamma ~ 1.7. The peak flux in the 20 -
200 keV band is determined to ~ 5.7 photons cm-2 s-1 and the GRB fluence to 1.1
x 10-5 erg cm-2. Analysing the spectral evolution of the GRB, a
``hard-to-soft'' behaviour emerges. A search for an optical counterpart has
been carried out, but none was found.


title: Neutrino-induced fission of neutron-rich nuclei

abstract:
  We calculate neutrino-induced fission cross sections for selected nuclei with
Z=84-92. We show that these reactions populate the daughter nucleus at
excitation energies where shell effects are significantly washed out,
effectively reducing the fission barrier. If the r-process occurs in the
presence of a strong neutrino fluence, and electron neutrino average energies
are sufficiently high, perhaps as a result of matter-enhanced neutrino flavor
transformation, then neutrino-induced fission could lead to significant
alteration in the r-process flow in slow outflow scenarios.


title:
The interaction of planets with a disc with MHD turbulence III: Flow
  morphology and conditions for gap formation in local and global simulations

abstract:
  We present the results of both global cylindrical disc simulations and local
shearing box simulations of protoplanets interacting with a disc undergoing MHD
turbulence with zero net flux magnetic fields. We investigate the nature of the
disc response and conditions for gap formation. This issue is an important one
for determining the type and nature of the migration of the protoplanet, with
the presence of a deep gap being believed to enable slower migration. For both
types of simulation we find a common pattern of behaviour for which the main
parameter determining the nature of the response is $M_p R^3/(M_* H^3)$, with
$M_p$, $M_*$, $R$, and $H$ being the protoplanet mass, the central mass, the
orbital radius and the disc semi-thickness respectively. We find that as this
parameter is increased towards 0.1, the presence of the protoplanet is first
indicated by the appearance of the well known trailing wake which, although it
may appear erratic on account of the turbulence, appears to be well defined.
Once the above parameter exceeds a number around unity a gap starts to develop
inside which the magnetic energy density tends to be concentrated in the high
density wakes. This gap formation condition can be understood from simple
dimensional considerations of the conditions for nonlinearity, and the balance
of angular momentum transport due to Maxwell and Reynolds' stresses with that
due to tidal torques. An important result is that the basic flow morphology in
the vicinity of the protoplanet is very similar in both the local and global
simulations. This indicates that local shearing box simulations, which are
computationally less demanding, capture much of the physics of disc-planet
interaction. Thus they may provide a useful tool for studying the local
interaction between forming protoplanets and turbulent, protostellar discs.


title: Thermal conduction and reduced cooling flows in galaxy clusters

abstract:
  Conduction may play an important role in reducing cooling flows in galaxy
clusters. We analyse a sample of sixteen objects using Chandra data and find
that a balance between conduction and cooling can exist in the hotter clusters
(T > 5 keV), provided the plasma conductivity is close to the unhindered
Spitzer value. In the absence of any additional heat sources, a reduced mass
inflow must develop in the cooler objects in the sample. We fit cooling flow
models to deprojected data and compare the spectral mass deposition rates found
to the values required to account for the excess luminosity, assuming
Spitzer-rate heat transfer over the observed temperature gradients. The mass
inflow rates found are lower than is necessary to maintain energy balance in at
least five clusters. However, emission from cooling gas may be partially
absorbed. We also compute the flux supplied by turbulent heat transport (Cho et
al. 2003) and find conductivity profiles which follow a strikingly similar
temperature dependence to the conductivity values required to prevent cooling.
Finally, we show that the cluster radio luminosities vary by over five orders
of magnitude in objects with X-ray luminosities differing by no more than a
factor of a few. This suggests that there is unlikely to be a straightforward
correlation between the mechanical power provided by the radio lobes and the
rate of energy loss in cooling flow clusters.


title: X-ray Bursts from the Accreting Millisecond Pulsar XTE J1814-338

abstract:
  Since the discovery of the accreting millisecond pulsar XTE J1814-338 a total
of 27 thermonuclear bursts have been observed from the source with the
Proportional Counter Array (PCA) onboard the Rossi X-ray Timing Explorer
(RXTE). Spectroscopy of the bursts, as well as the presence of continuous burst
oscillations, suggests that all but one of the bursts are sub-Eddington. The
remaining burst has the largest peak bolometric flux of 2.64 x E^-8
erg/sec/cm^2, as well as a gap in the burst oscillations, similar to that seen
in Eddington limited bursts from other sources. Assuming this burst was
Eddington limited we obtain a source distance of about 8 kpc. All the bursts
show coherent oscillations at the 314.4 Hz spin frequency. The burst
oscillations are strongly frequency and phase locked to the persistent
pulsations. Only two bursts show evidence for frequency drift in the first few
seconds following burst onset. In both cases the initial drift corresponds to a
spin down of a few tenths of a Hz. The large oscillation amplitude during the
bursts confirms that the burst flux is modulated at the spin frequency. We
detect, for the first time, a significant first harmonic component in burst
oscillations. The ratio of countrate in the first harmonic to that in the
fundamental can be > 0.25 and is, on average, less than that of the persistent
pulsations. If the pulsations result from a single bright region on the
surface, the harmonic strength suggests the burst emission is beamed, perhaps
due to a stronger magnetic field than in non-pulsing LMXBs. Alternatively, the
harmonic content could result from a geometry with two bright regions.


title:
The effect of cluster magnetic field on the Sunyaev Zeldovich power
  spectrum

abstract:
  Precision measurements of the Sunyaev Zeldovich (SZ) effect in upcoming blank
sky surveys require theoretical understanding of all physical processes with
$\ga 10%$ effects on the SZ power spectrum. We show that, observed cluster
magnetic field could reduce the SZ power spectrum by $\sim 20%$ at $l\sim
4000$, where the SZ power spectrum will be precisely measured by the Sunyaev
Zeldovich array (SZA) and the Atacama cosmology telescope (ACT). At smaller
scale, this effect is larger and could reach a factor of several. Such effect
must be considered for an unbiased interpretation of the SZ data. Though the
magnetic effect on the SZ power spectrum is very similar to that of radiative
cooling, it is measurable by multi-band CMB polarization measurement.


title:
Correlations Between the WMAP and MAXIMA Cosmic Microwave Background
  Anisotropy Maps

abstract:
  We cross-correlate the cosmic microwave background temperature anisotropy
maps from the WMAP, MAXIMA-I, and MAXIMA-II experiments. We use the
cross-spectrum, which is the spherical harmonic transform of the angular
two-point correlation function, to quantify the correlation as a function of
angular scale. We find that the three possible pairs of cross-spectra are in
close agreement with each other and with the power spectra of the individual
maps. The probability that there is no correlation between the maps is smaller
than 1 * 10^(-8). We also calculate power spectra for maps made of differences
between pairs of maps, and show that they are consistent with no signal. The
results conclusively show that the three experiments not only display the same
statistical properties of the CMB anisotropy, but also detect the same features
wherever the observed sky areas overlap. We conclude that the contribution of
systematic errors to these maps is negligible and that MAXIMA and WMAP have
accurately mapped the cosmic microwave background anisotropy.


title: Galactic-Field IMFs of Massive Stars

abstract:
  Over the past years observations of young and populous star clusters have
shown that the stellar IMF appears to be an invariant featureless Salpeter
power-law with an exponent alpha=2.35 for stars more massive than a few Msun. A
consensus has also emerged that most, if not all, stars form in stellar groups
and star clusters, and that the mass function of young star clusters in the
solar-neighborhood and in interacting galaxies can be described, over the mass
range of a few 10 Msun to 10^7 Msun, as a power-law with an exponent near
beta=2. These two results imply that galactic-field IMFs for early-type stars
cannot, under any circumstances, be a Salpeter power-law, but that they must
have a steeper exponent alpha_field>2.8. This has important consequences for
the distribution of stellar remnants and for the chemo-dynamical and
photometric evolution of galaxies.


title: Redshift-Distance Survey of Early-Type Galaxies: Spectroscopic Data

abstract:
  We present central velocity dispersions and Mg$_2$ line indices for an
all-sky sample of $\sim$ 1178 elliptical and S0 galaxies, of which 984 had no
previous measures. This sample contains the largest set of homogeneous
spectroscopic data for a uniform sample of elliptical galaxies in the nearby
universe. These galaxies were observed as part of the ENEAR project, designed
to study the peculiar motions and internal properties of the local early-type
galaxies. Using 523 repeated observations of 317 galaxies obtained during
different runs, the data are brought to a common zero-point. These multiple
observations, taken during the many runs and different instrumental setups
employed for this project, are used to derive statistical corrections to the
data and are found to be relatively small, typically $\lsim$ 5% of the velocity
dispersion and 0.01 mag in the \mg line-strength. Typical errors are about 8%
in velocity dispersion and 0.01 mag in \mg, in good agreement with values
published elsewhere.


title: Vortices in the Co-orbital Region of an Embedded Protoplanet

abstract:
  We present global 2-D inviscid disk simulations with an embedded planet,
emphasizing the non-linear dynamics in its co-orbital region. We find that the
potential vorticity of the flow in this region is not conserved due to the
presence of two spiral shocks produced by the planet. As the system evolves,
the potential vorticity profile develops extrema (inflection points) which
eventually render the flow unstable. Vortices are produced in association with
the potential vorticity minima. Born in the separatrix region, these vortices
experience close-encounters with the planet, consequently exerting strong
torques on the planet. The existence of these vortices have important
implications on understanding the migration rates of low mass planets.


title:
M Dwarfs from Hubble Space Telescope Star Counts. V. The I-band
  Luminosity Function

abstract:
  We derive the disk I-band luminosity function from the Zheng et al. sample of
\~1400 disk M dwarfs observed with the Hubble Space Telescope. We adopt a
Galactic-height-dependent color-magnitude relation to account for the
metallicity gradient above the Galactic plane. The resultant I-band luminosity
function peaks at M_I~9.5 and drops sharply toward M_I~10.5.


title:
The interaction of planets with a disc with MHD turbulence IV: Migration
  rates of embedded protoplanets

abstract:
  (Abridged) We present global disc and local shearing box simulations of
planets interacting with a MHD turbulent disc. We examine the torque exerted by
the disc on the embedded planets as a function of planet mass, and thus make a
first study of orbital migration of planets due to interaction with turbulent
discs. Global simulations were performed for a disc with H/R=0.07 and planet
masses M_p=3,10,30 Earth masses, and 3 Jupiter masses. Shearing box runs were
performed for values of (M_p/M_*)/(H/R)^3=0.1,0.3,1.0 and 2.0, M_* being the
central mass. These allow embedded and gap forming planets to be examined. In
all cases the instantaneous torque exerted on a planet showed strong
fluctuations. In the embedded cases it oscillated between negative and positive
values, and migration occurs as a random walk, unlike the usual type I
migration. Running time averages for embedded planets over 20-25 orbital
periods show that large fluctuations occur on longer time scales, preventing
convergence of the average torque to well defined values, or even to a well
defined sign. Fluctuations become relatively smaller for larger masses, giving
better convergence, due to the planet's perturbation of the disc becoming
larger than the turbulence in its vicinity. Eventually gap formation occurs,
with a transition to type II migration. The existence of significant
fluctuations occurring in turbulent discs on long time scales is important for
lower mass embedded protoplanets. If significant fluctuations occur on the
longest disc evolutionary time scales, convergence of torque running averages
for practical purposes will not occur, and the migration behaviour of low mass
protoplanets considered as an ensemble would be very different from predictions
of type I theory for laminar discs.


title: Magnetic Braking Revisited

abstract:
  We present a description for the angular momentum loss rate due to magnetic
braking for late type stars taking into account recent observational data on
the relationship between stellar activity and rotation. The analysis is based
on an idealized two component coronal model subject to constraints imposed on
the variation of the coronal gas density with rotation period inferred from the
observed variation of X-ray luminosity, L_x, with rotation rate, Omega, (L_x
\propto Omega^2) for single rotating dwarfs. An application of the model to
high rotation rates leads to a gradual turnover of the X-ray luminosity which
is similar to the saturation recently observed in rapidly rotating dwarfs. The
resulting angular momentum loss rate, \dot J, depends on Omega in the form \dot
J \propto Omega^beta where beta ~ 3 for slow rotators and ~ 1.3 for fast
rotators. The relation at high rotation rates significantly differs from the
power law exponent for slowly rotating stars, depressing the angular momentum
loss rate without necessarily requiring the saturation of the magnetic field.
The application of this model to the evolution of cataclysmic variable binary
systems leads to mass transfer rates that are in approximate accord with those
observed in comparison to rates based on either a Skumanich law or an empirical
law based on beta=1.


title: S986 in M67: A Totally-Eclipsing Binary at the Cluster Turnoff

abstract:
  We have discovered that the star S986 in the old open cluster M67 has
detectable total eclipses of depth 0.08 mag for the primary eclipse and 0.011
mag for the secondary eclipse (in I only). We confirm the detection of a third
star in spectra contributing 11.5% +/- 1.5% of the total light in V band. The
radial velocity of the third star indicates that it is a cluster member, but it
is unclear whether it is physically associated with the eclipsing binary. Using
spectroscopic and photometric data, we deconvolve the photometry of the three
stars, and find that the primary star in the eclipsing binary is significantly
hotter than the turnoff. The two most likely explanations are that the primary
star is in a rapid phase of evolution near core hydrogen exhaustion (associated
with the turnoff gap in M67's color-magnitude diagram), or that it is a blue
straggler created during a stellar collision earlier in the cluster's history.
Our detection of Li in the primary star tightly constrains possible formation
mechanisms in the blue straggler explanation. Because S986 is often used to
constrain tidal dissipation models, this may imply that the strength of tidal
effects is underestimated.


title:
Spectral and Timing Evolution of the Black Hole X-ray Nova 4U 1543-47
  During its 2002 Outburst

abstract:
  We present an X-ray spectral and timing analysis of 4U 1543-47 during its
2002 outburst based on 49 pointed observations obtained using the Rossi X-ray
Timing Explorer (RXTE). The outburst reached a peak intensity of 4.2 Crab in
the 2-12 keV band and declined by a factor of 32 throughout the month-long
observation. A 21.9 +- 0.6 mJy radio flare was detected at 1026.75 MHz two days
before the X-ray maximum; the radio source was also detected late in the
outburst, after the X-ray source entered the low hard state. The X-ray light
curve exhibits the classic shape of a rapid rise and an exponential decay. The
spectrum is soft and dominated by emission from the accretion disk. The
continuum is fit with a multicolor disk blackbody (kT_{max} = 1.04 keV) and a
power-law (Gamma ~ 2.7). Midway through the decay phase, a strong low-frequency
QPO (nu = 7.3-8.1 Hz) was present for several days. The spectra feature a broad
Fe K alpha line that is asymmetric, suggesting that the line is due to
relativistic broadening rather than Comptonization. Relativistic Laor models
provide much better fits to the line than non-relativistic Gaussian models,
particularly near the beginning and end of our observations. The line fits
yield estimates for the inner disk radius that are within 6 R_g; this result
and additional evidence indicates that this black hole may have a non-zero
angular momentum.


title: Age dependence of the Vega Phenomenon: Theory

abstract:
  In a separate paper (Decin et al 2003), we have re-examined the observations
of IR excess obtained with the ISO satellite and discussed the ages of stars
with excess. The amount of dust (measured by the luminosity fraction
\fdust=L_\mathrm{IR}/L_{\star}) seen around main-sequence stars of different
ages shows several interesting trends. To discuss these results in the context
of a physical model, we develop in this paper an analytical model for the dust
production in Vega-type systems. Previously it has been claimed that a powerlaw
slope of about -2 in the diagram plotting amount of dust versus time could be
explained by a simple collisional cascade. We show that such a cascade in fact
results in a powerlaw \fdust\propto t^{-1} if the dust removal processes are
dominated by collisions. A powerlaw \fdust\propto t^{-2} only results when the
dust removal processes become dominated by Pointing-Robertson drag. This may be
the case in the Kuiper Belt of our own solar system, but it is certainly not
the case in any of the observed disks. A steeper slope can, however, be created
by including continuous stirring into the models. We show that the existence of
both young and old Vega-like systems with large amounts of dust (\fdust\simeq
10^{-3}) can be explained qualitatively by Kuiper-Belt-like structures with
\emph{delayed stirring}. Finally, the absence of young stars with intermediate
amounts of dust may be due to the fact that stirring due to planet formation
may not be active in young low-mass disks. The considerations in this paper
support the picture of simultaneous stirring and dust production proposed by
Kenyon and Bromley (2002).