title:
The host galaxy/AGN connection in nearby early-type galaxies. Is there a
  miniature radio-galaxy in every "core" galaxy?

abstract:
  This is the second of a series of three papers exploring the connection
between the multiwavelength properties of AGN in nearby early-type galaxies and
the characteristics of their hosts. In Capetti et al. (2005) we presented a
study of the surface brightness profiles for the 65 objects with available
archival HST images out of the 116 radio-detected galaxies. We classified
early-type galaxies into ``core'' and ``power-law'' galaxies, discriminating on
the basis of the slope of their nuclear brightness profiles. Here we focus on
the 29 core galaxies (hereafter CoreG). We used HST and Chandra data to isolate
their nuclear emission. The CoreG invariably host radio-loud nuclei, with an
average radio-loudness parameter of Log R = 3.6. The optical and X-ray nuclear
luminosities correlate with the radio-core power, smoothly extending the
analogous correlations already found for low luminosity radio-galaxies. This
supports the interpretation of a common non-thermal origin of the nuclear
emission also for CoreG. The luminosities of the nuclear sources, most likely
dominated by jet emission, set firm upper limits, as low as L/L_Edd = 10^{-9}
in both the optical and X-ray band, on any emission from the accretion process.
The similarity of CoreG and LLRG indicates that they are drawn from the same
population of early-type galaxies. LLRG represent only the tip of the iceberg
associated with (relatively) high activity levels, with CoreG forming the bulk
of the population. A minimum black hole mass of M_{BH} = 10^8 M_sun is
apparently associated with the radio-loud nuclei in both CoreG and LLRG, but
this effect must be tested on a sample of less luminous galaxies, likely to
host smaller black holes. ABRIDGED.


title:
The ESO Nearby Abell Cluster Survey VIII. Morphological and spectral
  classification of galaxies

abstract:
  We have determined the morphological types of 2295 galaxies from the ESO
Nearby Abell Cluster Survey (ENACS) from CCD images made with the Dutch
telescope on La Silla. The reliability of our classification appears to be
quite comparable to that of other classifiers. Recalibration of the ENACS
spectral classification shows that early- and late- type galaxies can be
distinguished from their spectra with 83% reliability. Ellipticals and S0
galaxies cannot be distinguished spectrally, while spectral classification of
late spirals has a reliability of 70%. We derive average pseudo-colors and
linestrengths from the ENACS spectra for the galaxies of different
morphological types, considering bright (M <= -20) and faint (M > -20) subsets
of the galaxies without emission lines (non-ELG) separately. We find a strong
and significant correlation between the average color and the average strength
of the metal absorption lines. The average metallicity decreases and the
average color gets bluer towards later Hubble type. In each morphological class
the faint galaxies are bluer and less metal-rich than the bright ones. This
extends the well-established color-magnitude relation of early-type galaxies to
(late) spirals. Bright early spirals may, on average, have somewhat stronger
H-delta absorption than the other galaxies, which could be due to recent
starformation. The galaxies with emission lines (ELG) have a bluer spectral
continuum than the non-ELG, and the amount of blueing hardly depends on
morphological type. The fraction of ELG depends strongly on morphological type
but it varies very little with projected distance from the cluster center.


title:
Theoretical interpretation of luminosity and spectral properties of GRB
  031203

abstract:
  The X and gamma-ray observations of the source GRB 031203 by INTEGRAL are
interpreted within our theoretical model. In addition to a complete space-time
parametrization of the GRB, we specifically assume that the afterglow emission
originates from a thermal spectrum in the co-moving frame of the expanding
baryonic matter shell. By determining the two free parameters of the model and
estimating the density and filamentary structure of the ISM, we reproduce the
observed luminosity in the 20-200 keV energy band. As in previous sources, the
prompt radiation is shown to coincide with the peak of the afterglow and the
luminosity substructure are shown to originate in the filamentary structure of
the ISM. We predict a clear hard-to-soft behavior in the instantaneous spectra.
The time-integrated spectrum over 20 seconds observed by INTEGRAL is well
fitted. Despite this source has been considered "unusual", it appears to us a
normal low energetic GRB.


title: Microlensing of the Fe K$\alpha$ line and the X-ray continuum

abstract:
  The observed enhancement of the Fe K$\alpha$ line in three gravitationally
lensed QSOs (MG J0414+0534, QSO 2237+0305, H1413+117) is interpreted in terms
of microlensing, even when equivalent X-ray continuum amplification is not
observed. In order to interpret these observations, first we studied the
effects of microlensing on quasars spectra, produced by straight fold caustic
crossing over standard relativistic accretion disk. The disk emission was
analyzed using the ray tracing method, considering Schwarzschild and Kerr
metrics. When the emission is separated in two regions (an inner disk
corresponding to the Fe K$\alpha$ line and an outer annulus corresponding to
the continuum, or vice-versa) we find microlensing events which enhance the Fe
K$\alpha$ line without noticeable amplification of the X-ray continuum, but
only during a limited time interval. Continuum amplification is expected if a
complete microlensing event is monitored. Second, we studied a more realistic
case of amplification by caustic magnification pattern. In this case we could
satisfactorily explain the observations if the Fe K$\alpha$ line is emitted
from the innermost part of the accretion disk, while the continuum is emitted
from a larger region. Also, we studied the chromatic effects of microlensing,
finding that the radial distribution of temperature in the accretion disk,
combined with microlensing itself, can induce wavelength dependent variability
of $\sim$ 30% for microlenses with very small masses. All these results show
that X-ray monitoring of gravitational lenses is a well suited method for
studying of the innermost structure of AGN accretion disks.


title: WFMOS - Sounding the Dark Cosmos

abstract:
  Vast sound waves traveling through the relativistic plasma during the first
million years of the universe imprint a preferred scale in the density of
matter. We now have the ability to detect this characteristic fingerprint in
the clustering of galaxies at various redshifts and use it to measure the
acceleration of the expansion of the Universe. The Wide-Field Multi-Object
Spectrograph (WFMOS) would use this test to shed significant light on the true
nature of dark energy, the mysterious source of this cosmic acceleration. WFMOS
would also revolutionise studies of the kinematics of the Milky Way and provide
deep insights into the clustering of galaxies at redshifts up to z~4. In this
article we discuss the recent progress in large galaxy redshift surveys and
detail how WFMOS will help unravel the mystery of dark energy.


title:
Multiple helium abundances in Globular Clusters stars: Consequences for
  the Horizontal Branch and RR Lyrae

abstract:
  Most inhomogeneities in the chemical composition of GC stars are due to
primordial enrichment. The model today most credited is that the winds lost by
high mass Asymptotic Giant Branch (AGB) stars, evolving during the first
$\simlt$200Myr of the Clusters life, directly form a second generation of stars
with abundance anomalies. The best indirect hint towards this suggestion is the
recognition that some peculiarities in the Horizontal Branch (HB) stars
distribution (blue tails, gaps, anomalous luminosity slope of the flat part of
the HB) can be attributed to the larger helium abundance in the matter,
processed through Hot Bottom Burning, from which these stars are born. The
model has been reinforced by finding a peculiar main sequence distribution in
the cluster NGC 2808, which also has a bimodal HB distribution and an extended
blue tail: the excess of blue objects on the main sequence has been interpreted
as stars with very high helium. We remark that the RR Lyr distribution may be
affected by the helium spread, and this can be at the basis of the very long
periods of the RRab variables of the metal rich clusters NGC 6388 and NGC 6441,
longer than for the very metal poor Oosterhoff II clusters. These periods imply
that the RR Lyr are brighter than expected for their metallicities, consistent
with a larger helium abundance.


title:
CCD photometry of distant open clusters NGC 2425, Haffner 10 and Czernik
  29

abstract:
  We present BVI photometry for poorly known southern hemisphere open clusters:
NGC 2425, Haffner 10 and Czernik 29. We have calculated the density profile and
established the number of stars in each cluster. The colour-magnitude diagrams
of the objects show a well-defined main sequence. However, the red giant clump
is present only in NGC 2425 and Haffner 10. For these two clusters we estimated
the age as 2.5 +/- 0.5 Gyr assuming metallicity of Z=0.008. The apparent
distance moduli are in the ranges 13.2<(m-M)_V<13.6 and 14.3<(m-M)_V<14.7,
while heliocentric distances are estimated to be 2.9<d<3.8 kpc and 3.1<d<4.3
kpc, respectively for NGC 2425 and Haffner 10. The angular separation of 2.4
deg (150 pc at mean distance) may indicate a common origin of the two clusters.


title: Microlens Mass Functions

abstract:
  A non-parametric statistical model is constructed to directly relate The
distribution of observed microlens timescales to that of the mass Function of
the population from which the lenses are drawn, corrected For observational
selection based on timescales and event amplifications. Explicit distributions
are derived for microlensing impact parameters and maximum amplifications; both
are shown to be statistically independent of all other parameters in the
problem, including lens mass. The model is used to demonstrate that the narrow
range of microlens timescales observed toward the Large Magellanic Cloud (LMC)
is probably not consistent with lensing by a widely distributed spheroidal
population of large velocity dispersion, as expected of a dark halo; but is
consistent with lensing within a rotating thick disk. Poor numerical
conditioning on the statistical connection between lens masses and event
timescales, and small number statistics, severely limit the mass function
information obtainable from current microlensing surveys toward the LMC.


title:
Bardeen-Petterson effect and the disk structure of the Seyfert galaxy
  NGC 1068

abstract:
  VLBA high spatial resolution observations of the disk structure of the active
galactic nucleus NGC 1068 has recently revealed that the kinematics and
geometry of this AGN is well characterized by an outer disk of H2O maser
emission having a compact milliarcsecond (parsec) scale structure, which is
encircling a thin rotating inner disk surrounding a ~10^7 M$_\sun$ compact
mass, likely a black hole. A curious feature in this source is the occurrence
of a misalignment between the inner and outer parts of the disk, with the
galaxy's radio jet being orthogonal to the inner disk. We interpret this
peculiar configuration as due to the Bardeen-Petterson effect, a general
relativistic effect that warps an initially inclined (to the black hole
equator) viscous disk, and drives the angular momentum vector of its inner part
into alignment with the rotating black hole spin. We estimate the time-scale
for both angular momenta to get aligned as a function the spin parameter of the
Kerr black hole. We also reproduce the shape of the parsec and kiloparsec scale
jets, assuming a model in which the jet is precessing with a period and
aperture angle that decrease exponentially with time, as expected from the
Bardeen-Petterson effect.


title:
Rapid Spectral Variability during the 2003 Outburst of V4641 Sgr (= SAX
  J1819.3-2525)

abstract:
  The black hole candidate V4641 Sgr (= SAX J1819.3-2525) went through a brief
outburst during 2003 Aug 01 to Aug 08. During the outburst, activity was noted
in optical, radio as well as X-rays. Here we present results of Spectral and
Temporal analysis of a pointed Rossi X-ray Timing Explorer (RXTE) observation
of the source during the outburst. During this pointing we observed flaring
activities with associated X-ray luminosity variations over factors of 5 or
more in timescales of few tens of seconds. The observed flares during are
intrinsically different in their spectral and temporal properties. We see
evidence of variable column density during one of the flares. The spectral and
temporal analyses of the data suggest occasional outflow/mass ejection.


title: The central kinematics of NGC 1399 measured with 14pc resolution

abstract:
  We present near infra-red (NIR) adaptive optics assisted spectroscopic
observations of the CO ($\Delta\mu=2$) absorption bands towards the centre of
the giant elliptical galaxy NGC 1399. The observations were made with
NAOS-CONICA (ESO VLT) and have a FWHM resolution of 0\farcs15 (14pc). Kinematic
analysis of the observations reveals a decoupled core and strongly non-Gaussian
line-of-sight velocity profiles (VPs) in the central 0.2 arcsec (19pc). NIR
imaging also indicates an asymmetric elongation of the central isophotes in the
same region.
  We use spherical orbit-superposition models to interpret the kinematics,
using a set of orthogonal ``eigenVPs'' that allow us to fit models directly to
spectra. The models require a central black hole of mass
$1.2^{+0.5}_{-0.6}\times10^9M_\odot$, with a strongly tangentially biased orbit
distribution in the inner 40pc.


title: G0.57-0.018: A young supernova remnant? INTEGRAL and VLA observations

abstract:
  We report INTEGRAL/IBIS gamma-ray and VLA radio observations of G0.570-0.018,
a diffuse X-ray source recently discovered by ASCA and Chandra in the Galactic
center region. Based on its spectrum and morphology, G0.570-0.018 has been
proposed to be a very young supernova remnant. In this scenario, the presence
of gamma-ray lines coming from the short-lived radioactive nucleus 44Ti as well
as synchrotron radio continuum emission are expected. The first could provide
informations on nucleosynthesis environments in the interior of exploding
stars, the latter could probe the interaction between the supernova blast wave
and the circumstellar/interstellar matter. We have not detected 44Ti lines nor
any conspicuous radio feature associated with this source down to the achieved
sensitivities. From the derived upper limits we set constraints on the nature
of G0.570-0.018.


title:
The pure non-collisional Blue Straggler population in the giant stellar
  system omega Centauri

abstract:
  We have used high spatial resolution data from the Hubble Space Telescope and
wide-field ground-based observations to search for blue straggler stars (BSS)
over the entire radial extent of the large stellar system omega Centauri. We
have detected the largest population of BSS ever observed in any stellar
system. Even though the sample is restricted to the brightest portion of the
BSS sequence, more than 300 candidates have been identified. BSS are thought to
be produced by the evolution of binary systems (either formed by stellar
collisions or mass exchange in binary stars). Since systems like Galactic
globular clusters (GGC) and omega Cen evolve dynamically on time-scales
significantly shorter than their ages, binaries should have settled toward the
center, showing a more concentrated radial distribution than the ordinary, less
massive single stars. Indeed, in all GGCs which have been surveyed for BSS, the
BSS distribution is peaked at the center. Conversely, in omega Cen we find that
the BSS share the same radial distribution as the adopted reference
populations. This is the cleanest evidence ever found that such a stellar
system is not fully relaxed even in the central region. We further argue that
the absence of central concentration in the BSS distribution rules out a
collisional origin. Thus, the omega Cen BSS are the purest and largest
population of non-collisional BSS ever observed. Our results allow the first
empirical quantitative estimate of the production rate of BSS via this channel.
BSS in omega Cen may represent the best local template for modeling the BSS
populations in distant galaxies where they cannot be individually observed.


title:
The ESO Nearby Abell Cluster Survey IX. The morphology-radius and
  morphology-density relations in rich galaxy clusters

abstract:
  We study the morphology-radius (MR-) and morphology-density (MD-) relations
for a sample of about 850 galaxies (with M <= -19.5) in 23 clusters from the
ENACS (ESO Nearby Abell Cluster Survey). On the basis of their radial
distributions we must distinguish: 1. brightest ellipticals (with M < -22), 2.
late spirals, and 3. the ensemble of less bright ellipticals, S0 galaxies and
early spirals. The latter have indistinguishable distributions of projected
radial distance R. The brightest ellipticals are most centrally concentrated,
the late spirals are almost absent from the central regions and the other
classes are intermediate. Radial segregation of the ellipticals is due to the
brightest ellipticals only, that of the spirals to the late spirals only. We
derive the MD-relation with two measures of projected density: one using the 10
nearest neighbours (Sigma10) and another using only the nearest neighbour
(Sigma1). The Sigma10 MD-relation only shows a significant difference between
early- and late-type galaxies, but the different galaxy types within those
classes are indistinguishable. However, The Sigma1 MD-relation shows that the
normal 'ellipticals' (with M >= -22), the S0 galaxies and the early spirals
have different Sigma1-distributions. The reason for this is that Sigma1 is much
less correlated with R than is Sigma10, and thus has much less cross-talk from
the (MR-) relation. On average, the 'normal' ellipticals populate environments
with higher projected density than do the S0 galaxies while the early spirals
populate even less dense environments. The segregation of the brightest
ellipticals and the late spirals is driven mostly by global factors, while the
segregation between 'normal' ellipticals, S0 galaxies and early spirals is
driven primarily by local factors.


title:
Unveiling the nature of Ultraluminous Infrared Galaxies with 3-4 micron
  spectroscopy

abstract:
  We present the results of L-band spectroscopical observations of local bright
ULIRGs, performed with ISAAC at the VLT. We discuss the L-band spectral
features of seven single sources, and the statistical properties of a complete
sample of 15 sources obtained combining our observations with other published
3-4 micron spectra. Our main results are: 1. When a spectral indicator
suggesting the presence of an AGN (low equivalent width of the 3.3 micron
emission line, steep lambda-f_lambda spectrum, presence of an absorption
feature at 3.4 micron) is found, the AGN is always confirmed by independent
analysis at other wavelengths. Conversely, in all known AGNs at least one of
the above indicators is present. 2. Two new diagnostic diagrams are proposed
combining the above indicators, in which starbursts and AGNs are clearly and
completely separated. 3. The above diagnostic techniques are possible with
spectra of relatively low quality, which can be obtained for several tens of
ULIRGs with currently available telescopes. This makes L-band spectroscopy the
current best tool to disentangle AGNs and starbursts contributions in ULIRGs.
4. The L-band properties of ULIRGs are heterogeneous. However, we show that all
the spectral differences among ULIRGs can be reproduced starting from pure
intrinsic AGN and SB spectra and varying two parameters: the amount of dust
extinction of the AGN component, and the relative AGN/SB contribution to the
bolometric luminosity. 5. Using the above decomposition model, we show that
AGNs in ULIRGs have a low dust-to-gas ratio and a dust extinction curve
different from Galactic. 6. The estimate of the contribution of AGNs in a
complete sample show that AGNs are hosted by ~2/3 of ULIRGs, but their
energetic contribution is relevant only in ~20% of the sample.


title:
Radio emission models of Colliding-Wind Binary Systems - Inclusion of IC
  cooling

abstract:
  Radio emission models of colliding wind binaries (CWBs) have been discussed
by Dougherty et al. (2003). We extend these models by considering the temporal
and spatial evolution of the energy distribution of relativistic electrons as
they advect downstream from their shock acceleration site. The energy spectrum
evolves significantly due to the strength of inverse-Compton (IC) cooling in
these systems, and a full numerical evaluation of the synchrotron emission and
absorption coefficients is made. We have demonstrated that the geometry of the
WCR and the streamlines of the flow within it lead to a spatially dependent
break frequency in the synchrotron emission. We therefore do not observe a
single, sharp break in the synchrotron spectrum integrated over the WCR, but
rather a steepening of the synchrotron spectrum towards higher frequencies. We
also observe that emission from the wind-collision region (WCR) may appear
brightest near the shocks, since the impact of IC cooling on the non-thermal
electron distribution is greatest near the contact discontinuity (CD). We show
that the thermal emission from a CWB can mimic a thermal plus non-thermal
composite spectrum if the thermal emission from the WCR becomes comparable to
that from the unshocked winds, and obtain a number of insights relevant to
models of closer systems such as WR140. Finally, we apply our new models to the
very wide system WR147. The acceleration of non-thermal electrons appears to be
very efficient in our models of WR147, and we suggest that the shock structure
may be modified by feedback from the accelerated particles. (Abridged).


title:
High-resolution simulations of the final assembly of Earth-like planets
  1: terrestrial accretion and dynamics

abstract:
  The final stage in the formation of terrestrial planets consists of the
accumulation of ~1000-km ``planetary embryos'' and a swarm of billions of 1-10
km ``planetesimals.'' During this process, water-rich material is accreted by
the terrestrial planets via impacts of water-rich bodies from beyond roughly
2.5 AU. We present results from five high-resolution dynamical simulations.
These start from 1000-2000 embryos and planetesimals, roughly 5-10 times more
particles than in previous simulations.
  Each simulation formed 2-4 terrestrial planets with masses between 0.4 and
2.6 Earth masses. The eccentricities of most planets were ~0.05, lower than in
previous simulations, but still higher than for Venus, Earth and Mars. Each
planet accreted at least the Earth's current water budget.
  We demonstrate several new aspects of the accretion process: 1) The feeding
zones of terrestrial planets change in time, widening and moving outward. Even
in the presence of Jupiter, water-rich material from beyond 2.5 AU is not
accreted for several millions of years. 2) Even in the absence of secular
resonances, the asteroid belt is cleared of >99% of its original mass by
self-scattering of bodies into resonances with Jupiter. 3) If planetary embryos
form relatively slowly, following the models of Kokubo & Ida, then the
formation of embryos in the asteroid belt may have been stunted by the presence
of Jupiter. 4) Self-interacting planetesimals feel dynamical friction from
other small bodies, which has important effects on the eccentricity evolution
and outcome of a simulation.


title:
High-resolution simulations of the final assembly of Earth-like planets
  2: water delivery and planetary habitability

abstract:
  The water content and habitability of terrestrial planets are determined
during their final assembly, from perhaps a hundred 1000-km "planetary embryos"
and a swarm of billions of 1-10 km "planetesimals." During this process, we
assume that water-rich material is accreted by terrestrial planets via impacts
of water-rich bodies that originate in the outer asteroid region. We present
analysis of water delivery and planetary habitability in five high-resolution
simulations containing about ten times more particles than in previous
simulations (Raymond et al 2006a, Icarus, 183, 265-282). These simulations
formed 15 terrestrial planets from 0.4 to 2.6 Earth masses, including five
planets in the habitable zone. Every planet from each simulation accreted at
least the Earth's current water budget; most accreted several times that amount
(assuming no impact depletion). Each planet accreted at least five water-rich
embryos and planetesimals from past 2.5 AU; most accreted 10-20 water-rich
bodies.
  We present a new model for water delivery to terrestrial planets in
dynamically calm systems, with low-eccentricity or low-mass giant planets --
such systems may be very common in the Galaxy. We suggest that water is
accreted in comparable amounts from a few planetary embryos in a "hit or miss"
way and from millions of planetesimals in a statistically robust process.
Variations in water content are likely to be caused by fluctuations in the
number of water-rich embryos accreted, as well as from systematic effects such
as planetary mass and location, and giant planet properties.


title:
A posteriori detection of the planetary transit of HD189733b in the
  Hipparcos photometry

abstract:
  Thanks to observations performed at the Haute-Provence Observatory, Bouchy et
al. recently announced the detection of a 2.2-day orbital period extra-solar
planet that transits the disk of its parent star, HD189733. With high level of
confidence, we find that Hipparcos likely observed one transit of HD189733b in
October 1991, and possibly two others in February 1991 and February 1993. Using
the range of possible periods for HD189733b, we find that the probability that
none of those events are due to planetary transits but are instead all due to
artifacts is lower than 0.15%. Thanks to the 15-year temporal baseline
available, we can measure the orbital period of the planet HD189733b with a
particularly high accuracy. We obtain a period of 2.218574
(+0.000006/-0.000010) days, corresponding to an accuracy of ~1 second. Such
accurate measurements might provide clues for companions presence.


title: Evolution of the magnetic field in magnetars

abstract:
  We use numerical MHD to look at the stability of a possible poloidal field in
neutron stars (Flowers & Ruderman 1977), and follow its unstable evolution,
which leads to the complete decay of the field. We then model a neutron star
after the formation of a solid crust of high conductivity. As the initial
magnetic field we use the stable `twisted torus' field which was the result of
our earlier work (Braithwaite & Nordlund 2005), since this field is likely to
exist in the interior of the star at the time of crust formation. We follow the
evolution of the field under the influence of diffusion, and find that large
stresses build up in the crust, which will presumably lead to cracking. We put
this forward as a model for outbursts in soft gamma repeaters.


title:
Detailed spectroscopic analysis of the Trapezium cluster stars inside
  the Orion nebula

abstract:
  We present the results of a spectroscopic analysis of the Trapezium cluster
stars inside the Orion Nebula. The rotational velocities have been obtained
using Fourier analysis method, finding agreement with values derived from the
usual method, based on linewidth measurements. The rotational velocity derived
for theta 1 Ori C through this method is consistent with the variability of
some of its spectral features that have a period of 15.42 days. By means of the
fit of H, HeI and HeII observed profiles with FASTWIND synthetic profiles,
stellar parameters and wind characteristics have been derived. This methodology
let us estimate the errors associated with these parameters. It is found that
macroturbulence effects have to be included for a good fit to the HeI-II lines
in the spectrum of theta 1 Ori C. By means of a very accurate study, oxygen
abundances have been derived for the three B0.5V stars theta 1 Ori A, D and
theta 2 Ori B. Final abundances are consistent with the nebular gas-phase
results presented in Esteban et al. (2004) and are lower than those given by
Cunha and Lambert (1994). Our results suggest a lower dust depletion factor of
oxygen than previous estimations for the Orion nebula.


title: Effects of Type I Migration on Terrestrial Planet Formation

abstract:
  Planetary embryos embedded in a gas disc suffer a decay in semimajor axis --
type I migration -- due to the asymmetric torques produced by the interior and
exterior wakes raised by the body (Goldreich & Tremaine 1980; Ward 1986). This
presents a challenge for standard oligarchic approaches to forming the
terrestrial planets (Kokubo & Ida 1998) as the timescale to grow the progenitor
objects near 1 AU is longer than that for them to decay into the Sun. In this
paper we investigate the middle and late stages of oligarchic growth using both
semi-analytic methods (based upon Thommes et al. 2003) and N-body integrations,
and vary gas properties such as dissipation timescale in different models of
the protoplanetary disc. We conclude that even for near-nominal migration
efficiencies and gas dissipation timescales of ~1 Myr it is possible to
maintain sufficient mass in the terrestrial region to form Earth and Venus if
the disc mass is enhanced by factors of ~2-4 over the minimum mass model. The
resulting configurations differ in several ways from the initial conditions
used in previous simulations of the final stages of terrestrial accretion (e.g.
Chambers 2001), chiefly in (1) larger inter-embryo spacings, (2) larger embryo
masses, and (3) up to ~0.4 Earth masses of material left in the form of
planetesimals when the gas vanishes. The systems we produce are reasonably
stable for ~100 Myr and therefore require an external source to stir up the
embryos sufficiently to produce final systems resembling the terrestrial
planets.


title:
Large-scale molecular shocks in galaxies: the SiO interferometer map of
  IC342

abstract:
  (Abridged) We present the first high-resolution (5.6''x5.1'') images of the
emission of silicon monoxide (SiO) in the nearby spiral IC342, obtained with
the IRAM Plateau de Bure Interferometer. We have mapped the emission of the
SiO(2-1) and H13CO+(1-0) lines in a 0.9kpcx1.3kpc region around the nucleus of
IC342. The bulk of the line emission comes from a 290pc spiral arm and a r~80pc
nuclear ring. The distribution of SiO clouds is mostly anticorrelated with the
continuum emission at 87GHz, dominated by thermal free-free bremsstrahlung. The
SiO/H13CO+ intensity ratio increases by an order of magnitude from the nuclear
ring to the spiral arm. Furthermore the gas kinematics show significant
differences between SiO and H13CO+ over the spiral arm, where the linewidths of
SiO are 2 times larger than that of H13CO+. The average abundance of SiO in the
inner r~320pc, X(SiO)>2x10^{-10}, evidences that shock chemistry is at work in
IC342. We have compared the emission of SiO with another tracer of molecular
shocks: the emission of methanol (CH3OH). The significant difference of the
X(SiO) measured between the spiral arm (~a few 10^{-9}) and the nuclear ring
(~10^{-10}) is not echoed by a comparable variation in the SiO/CH3OH intensity
ratio. This implies that the typical shock velocities should be similar in both
regions. In contrast, the fraction of shocked molecular gas should be 5-7 times
larger in the spiral arm (up to ~10% of the available molecular gas mass over
the arm region) compared to the nuclear ring. We conclude that the large-scale
shocks revealed by the SiO map of IC342 are mostly unrelated with star
formation and arise instead in a pre-starburst phase. Shocks are driven by
cloud-cloud collisions along the potential well of the IC342 bar. The general
implications for the current understanding of galaxy evolution are discussed.


title:
Testing Global ISM Models: A Detailed Comparison of Ovi Column Densities
  with FUSE and Copernicus Data

abstract:
  We study the ovi distribution in space and time in a representative section
of the Galactic disk by 3D adaptive mesh refinement HD and MHD simulations of
the ISM, including the disk-halo-disk circulation. The simulations describe a
supernova driven ISM on large (10 kpc) and small (1.25 pc) scales over a
sufficiently large timescale (400 Myrs) in order to establish a global
dynamical equilibrium. The Ovi column density, N(Ovi), is monitored through
lines of sight measurements at different locations in the simulated disk. One
has been deliberately chosen to be inside of a hot bubble, like our own Local
Bubble, while the other locations are random. We obtain a correlation between
N(Ovi) and distance, which is independent of the observer's vantage point in
the disk. In particular, the location of the observer inside a hot bubble does
not have any influence on the correlation, because the contribution of an
individual bubble (with a typical extension of 100 pc) is negligibly small. We
find a remarkable agreement between the Ovi column densities (as a function of
distance) and the averaged Ovi density (~1.8x10^{-8}$ cm$^{-3}$) in the disk
from our simulations and the values observed with Copernicus, and FUSE. Our
results strongly support the important r\^ole of turbulent mixing in the
distribution of Ovi clumps in the ISM. Supernova induced turbulence is quite
strong and unavoidable due to shearing motions in the ISM and operates on a
large range of scales.


title: Modelling Relativistic Astrophysics at the Large and Small Scale

abstract:
  In this thesis different numerical methods, as well as applications of the
methods to a number of current problems in relativistic astrophysics, are
presented. In the first part the theoretical foundation and numerical
implementation of a new general relativistic magnetohydrodynamics code is
discussed. A new form of the equations of motion using global coordinates, but
evolving the dynamical variables from the point of view of a local observer is
presented. No assumptions are made about the background metric and the design
is ready to be coupled with methods solving the full Einstein equations. In the
second part of the thesis important results concerning the understanding of
collisionless shocks, obtained from experiments with a relativistic charged
particle code, are presented. Relativistic collisionless shocks are important
in a range of astrophysical objects; in particular in gamma ray burst
afterglows and other relativistic jets. It is shown that a strong small scale,
fluctuating, and predominantly transversal magnetic field is unavoidably
generated by a two-stream instability. The magnetic energy density reaches a
few percent of equipartition. A new acceleration mechanism for electrons in
ion-electron collisionless shocks is proposed. The mechanism is capable of
creating a powerlaw electron distribution in a collisionless shocked region.
The non-thermal acceleration of the electrons is directly related to the ion
current channels generated by the two-stream instability and is local in
nature. Thus the observed radiation field may be tied directly to the local
conditions of the plasma and could be a strong handle on the physical
processes. (abridged)


title: Investigating dark energy experiments with principal components

abstract:
  We use a principal component approach to contrast different kinds of probes
of dark energy, and to emphasize how an array of probes can work together to
constrain an arbitrary equation of state history w(z). We pay particular
attention to the role of the priors in assessing the information content of
experiments and propose using an explicit prior on the degree of smoothness of
w(z) that is independent of the binning scheme. We also show how a figure of
merit based on the mean squared error probes the number of new modes
constrained by a data set, and use it to examine how informative various
experiments will be in constraining the evolution of dark energy.


title:
The Formation and Evolution of Planetary Systems (FEPS): Discovery of an
  Unusual Debris System Associated with HD 12039

abstract:
  We report the discovery of a debris system associated with the $\sim 30$ Myr
old G3/5V star HD 12039 using {\it Spitzer Space Telescope} observations from
3.6 -- 160$\mu$m. An observed infrared excess (L$_{\rm IR}$/L$_{\ast} =
1\times10^{-4}$) above the expected photosphere for $\lambda \gtrsim 14\mu$m is
fit by thermally emitting material with a color temperature of T$\sim 110$ K,
warmer than the majority of debris disks identified to date around Sun-like
stars. The object is not detected at 70$\mu$m with a 3$\sigma$ upper limit 6
times the expected photospheric flux. The spectrum of the infrared excess can
be explained by warm, optically thin material comprised of blackbody-like
grains of size $\gtrsim 7 \mu$m that reside in a belt orbiting the star at 4--6
AU. An alternate model dominated by smaller grains, near the blow-out size
$a\sim 0.5\mu$m, located at 30-40AU is also possible, but requires the dust to
have been produced recently since such small grains will be expelled from the
system by radiation pressure in $\sim$ few $\times 10^{2}$yrs.


title: Neon and Oxygen Abundances in M33

abstract:
  We present new spectroscopic observations of 13 H II regions in the Local
Group spiral galaxy M33. The regions observed range from 1 to 7 kpc in distance
from the nucleus. Of the 13 H II regions observed, the [O III] 4363 Angstrom
line was detected in six regions. Electron temperatures were thus able to be
determined directly from the spectra using the [O III] 4959,5007 A/4363 A line
ratio. Based on these temperature measurements, oxygen and neon abundances and
their radial gradients were calculated. For neon, a gradient of -0.016 +/-
0.017 dex/kpc was computed, which agrees with the Ne/H gradient derived
previously from ISO spectra. A gradient of -0.012 +/- 0.011 dex/kpc was
computed for O/H, much shallower than was derived in previous studies. The
newly calculated O/H and Ne/H gradients are in much better agreement with each
other, as expected from predictions of stellar nucleosynthesis. We examine the
correlation between the WC/WN ratio and metallicity, and find that the new M33
abundances do not impact the observed correlation significantly. We also
identify two new He II-emitting H II regions in M33, the first to be discovered
in a spiral galaxy other than the Milky Way. In both cases the nebular He II
emission is not associated with Wolf-Rayet stars. Therefore, caution is
warranted in interpreting the relationship between nebular He II emission and
Wolf-Rayet stars when both are observed in the integrated spectrum of an H II
region.


title: Eccentricities of Planets in Binary Systems

abstract:
  The most puzzling property of the extrasolar planets discovered by recent
radial velocity surveys is their high orbital eccentricities, which are very
difficult to explain within our current theoretical paradigm for planet
formation. Current data reveal that at least 25% of these planets, including
some with particularly high eccentricities, are orbiting a component of a
binary star system. The presence of a distant companion can cause significant
secular perturbations in the orbit of a planet. At high relative inclinations,
large-amplitude, periodic eccentricity perturbations can occur. These are known
as "Kozai cycles" and their amplitude is purely dependent on the relative
orbital inclination. Assuming that every planet host star also has a (possibly
unseen, e.g., substellar) distant companion, with reasonable distributions of
orbital parameters and masses, we determine the resulting eccentricity
distribution of planets and compare it to observations? We find that
perturbations from a binary companion always appear to produce an excess of
planets with both very high (e>0.6) and very low (e<0.1) eccentricities. The
paucity of near-circular orbits in the observed sample implies that at least
one additional mechanism must be increasing eccentricities. On the other hand,
the overproduction of very high eccentricities observed in our models could be
combined with plausible circularization mechanisms (e.g., friction from
residual gas) to create more planets with intermediate eccentricities
(e=0.1-0.6).


title:
Mopra Observations of G305.2+0.2: Massive Star Formation at Different
  Evolutionary Stages?

abstract:
  We have successfully used a new on-the-fly mapping technique with the Mopra
radiotelescope to image G305.2+0.2 in transitions of 13CO, HCO+, N2H+, CH3CN
and CH3OH. All these species appear to be concentrated towards the
infrared-quiet methanol maser site G305A (G305.21+0.21). We suggest that this
region contains an extremely deeply embedded site of massive star formation,
with comparable qualities to the low mass Class 0 stage. The infrared-bright
methanol maser site G305B (G305.21+0.20) also exhibits emission in all the
mapped transitions, but always at a lower level. We suggest this is because it
harbours a site of massive star formation older and more developed than
G305.21+0.21. All transitions appear to be extended beyond the size of the
Mopra beam (30"). 13CO and HCO+ line wings are suggestive of an outflow in the
region, but the spatial resolution of these data is insufficient to identify
the powering source. A narrow-lined (1.6 km/s compared to a typical line FWHM
of 6.4 km/s) N2H+ source (G305SW) is found 90" to the south-west of the main
star forming centres, which does not correspond to any CH3CN or CH3OH source,
nor does it correspond well to 13CO or HCO+ emission in the vicinity. We
suggest this may be a massive, cold, quiescent and possibly prestellar core.


title:
The Araucaria Project: The Distance to NGC 300 from the Red Giant Branch
  Tip using HST/ACS imaging

abstract:
  We have used the Advanced Camera for Surveys on board the Hubble Space
Telescope to obtain deep photometry of the NGC 300 spiral galaxy in the
Sculptor group. The results have been used to derive an accurate distance
determination based on the Tip of the Red Giant Branch distance estimator. Both
edge-detection and maximum likelihood methods have been applied, to derive a
distance modulus (m-M)_0=26.30 +/- 0.03 +/- 0.12 for edge-detection, and
(m-M)_0=26.36 +/- 0.02 +/- 0.12 for maximum likelihood. These results are fully
consistent with the recent distance estimate derived from near-IR photometry of
Cepheids variable stars in the context of the Araucaria project, (m-M)_0= 26.37
+/- 0.05 +/- 0.03.


title:
A wide area survey for high-redshift massive galaxies. I. Number counts
  and clustering of BzKs and EROs

abstract:
  We have combined deep BRIz' imaging over 2x940 arcmin^2 fields obtained with
the Suprime-Cam on the Subaru telescope with JKs imaging with the SOFI camera
at the New Technology Telescope to search for high-redshift massive galaxies.
K-band selected galaxies have been identified over an area of ~920 arcmin^2 to
K_Vega=19.2, of which 320 arcmin^2 are complete to K_Vega=20. The BzK selection
technique was used to obtain complete samples of ~500 candidate massive
star-forming galaxies (sBzKs) and ~160 candidate massive, passively-evolving
galaxies (pBzKs), both at 1.4<z<2.5. With the (R-K)_Vega > 5 criterion we also
identified ~850 extremely red objects (EROs). The surface density of sBzKs and
pBzKs is found to 1.20+/-0.05 arcmin^{-2} and 0.38+/-0.03 arcmin^{-2},
respectively. Both sBzKs and pBzKs are strongly clustered, at a level at least
comparable to that of EROs, with pBzKs appearing more clustered than sBzKs. We
estimate the reddening, star formation rates (SFRs) and stellar masses (M_*) of
the sBzKs, confirming that to K_Vega~20 median values are M_*~10^{11}M_sun, SFR
190M_sun yr^{-1}, and E(B-V)~0.44. The most massive sBzKs are also the most
actively star-forming, an effect which can be seen as a manifestation of
downsizing at early epochs. The space density of massive pBzKs at z~1.4-2 is
20%+/-7% that of similarly massive early-type galaxies at z~0, and similar to
that of sBzKs of the same mass. We argue that star formation quenching in these
sBzKs will result in nearly doubling the space density of massive early-type
galaxies, thus matching their local density.


title:
A Search for sub-TeV Gamma-rays from the Vela Pulsar Region with
  CANGAROO-III

abstract:
  We made stereoscopic observations of the Vela Pulsar region with two of the
10 m diameter CANGAROO-III imaging atmospheric Cherenkov telescopes in January
and February, 2004, in a search for sub-TeV gamma-rays from the pulsar and
surrounding regions. We describe the observations, provide a detailed account
of the calibration methods, and introduce the improved and bias-free analysis
techniques employed for CANGAROO-III data. No evidence of gamma-ray emission is
found from either the pulsar position or the previously reported position
offset by 0.13 degree, and the resulting upper limits are a factor of five less
than the previously reported flux from observations with the CANGAROO-I 3.8 m
telescope. Following the recent report by the H.E.S.S. group of TeV gamma-ray
emission from the Pulsar Wind Nebula, which is $\sim$0.5 degree south of the
pulsar position, we examined this region and found supporting evidence for
emission extended over $\sim$0.6 degree.


title:
Broadband Optical Properties of Massive Galaxies: the Dispersion Around
  the Field Galaxy Color-Magnitude Relation Out to z~0.4

abstract:
  Using a sample of nearly 20,000 massive early-type galaxies selected from the
Sloan Digital Sky Survey, we study the color-magnitude relation for the most
luminous (L > 2.2 L^{*}) field galaxies in the redshift range 0.1<z<0.4 in
several colors. The intrinsic dispersion in galaxy colors is quite small in all
colors studied, but the 40 milli-mag scatter in the bluest colors is a factor
of two larger than the 20 milli-mag measured in the reddest bands. While each
of three simple models constructed for the star formation history in these
systems can satisfy the constraints placed by our measurements, none of them
produce color distributions matching those observed. Subdividing by
environment, we find the dispersion for galaxies in clusters to be about 11%
smaller than that of more isolated systems. Finally, having resolved the red
sequence, we study the color dependence of the composite spectra. Bluer
galaxies on the red sequence are found to have more young stars than red
galaxies; the extent of this spectral difference is marginally better described
by passive evolution of an old stellar population than by a model consisting of
a recent trace injection of young stars.


title: Multiplicity of chemically peculiar stars

abstract:
  Recently, with the goal to study multiplicity of chemically peculiar stars,
we carried out a survey of 40 stars using diffraction limited near infrared
(IR) imaging with NAOS-CONICA (NACO) at the VLT. Here, we announce the
detection of 27 near IR companion candidates around 25 late B-type chemically
peculiar stars exhibiting strong overabundances of the chemical elements Hg and
Mn in their atmospheres. A key point for the understanding of the abundance
patterns in these stars may be connected with binarity and multiplicity. It is
intriguing that more than half of the sample of HgMn stars studied previously
by speckle interferometry and recently using the adaptive optics system NACO
belong to multiple systems.


title: Oscillations on the star Procyon

abstract:
  Stars are sphere of hot gas whose interiors transmit acoustic waves very
efficiently. Geologists learn about the interior structure of Earth by
monitoring how seismic waves propagate through it and, in a similar way, the
interior of a star can be probed using the periodic motions on the surface that
arise from such waves. Matthews et al. claim that the star Procyon does not
have acoustic surface oscillations of the strength predicted. However, we show
here, using ground-based spectroscopy, that Procyon is oscillating, albeit with
an amplitude that is only slightly greater than the noise level observed by
Matthews et al. using spaced-based photometry.


title: Evidence for chimney breakout in the Galactic supershell GSH 242-03+37

abstract:
  We present new high resolution neutral hydrogen (H I) images of the Galactic
supershell GSH 242-03+37. These data were obtained with the Parkes
Radiotelescope as part of the Galactic All-Sky Survey (GASS). GSH 242-03+37 is
one of the largest and most energetic H I supershells in the Galaxy with a
radius of $565 \pm 65$ pc and an expansion energy of 3x10^{53} ergs. Our images
reveal a complicated shell with multiple chimney structures on both sides of
the Galactic plane. These chimneys appear capped by narrow filaments about 1.6
kpc above and below the Galactic mid-plane, confirming structures predicted in
simulations of expanding supershells. The structure of GSH 242-03+37 is
extremely similar to the only other Galactic supershell known to have blown out
of both sides of the plane, GSH 277+00+36. We compare the GASS H I data with
X-ray and H-alpha, finding no strong correlations.


title: Hydraulic/Shock-Jumps in Protoplanetary Disks

abstract:
  In this paper, we describe the nonlinear outcome of spiral shocks in
protoplanetary disks. Spiral shocks, for most protoplanetary disk conditions,
create a loss of vertical force balance in the post-shock region and result in
rapid expansion of the gas perpendicular to the disk midplane. This expansion
has characteristics similar to hydraulic jumps, which occur in incompressible
fluids. We present a theory to describe the behavior of these hybrids between
shocks and hydraulic jumps (shock bores) and then compare the theory to
three-dimensional hydrodynamics simulations. We discuss the fully
three-dimensional shock structures that shock bores produce and discuss
possible consequences for disk mixing, turbulence, and evolution of solids.


title: Evolution of PAH Features from Proto- to Planetary Nebulae

abstract:
  With the aim to investigate the overall evolution of UIR band features with
hardening of UV radiation (increase of the star's effective temperature) we
have analysed ISO spectra for 32 C-rich stars: 20 proto-planetary nebulae and
12 planetary nebulae with Wolf-Rayet central stars. In this contribution we
discuss variations in the peak position of UIR bands among analysed objects,
and demonstrate that variations in the ``7.7'' to 11.3 microns flux ratio are
correlated with the effective temperature (probably due to an increase of the
ionization state of their carriers).


title:
Luminous AGB stars in nearby galaxies. A study using Virtual Observatory
  tools

abstract:
  Aims. This study focuses on very luminous Mbol<-6.0 mag AGB stars with
J-Ks>1.5 mag and H-Ks>0.4 mag in the LMC, SMC, M31, and M33 from 2MASS data.
  Methods.The data were taken from the 2MASS All-Sky Point Source catalogue
archive. We used Virtual Observatory tools and took advantage of its
capabilities at various stages in the analysis.
  Results. It is well known that stars with the colors we selected correspond
mainly to carbon stars. Although the most luminous AGBs detected here contain a
large number of carbon stars,they are not included in existing catalogues
produced from data in the optical domain, where they are not visible since they
are dust-enshrouded. A comparison of the AGB stars detected with combined near
and mid-infrared data from MSX and 2MASS in the LMC shows that 10% of the
bright AGB stars are bright carbon stars never detected before and that the
other 50% are OH/IR oxygen rich stars, whereas the 40% that remain were not
cross-matched.
  Conclusions. The catalogues of the most luminous AGB stars compiled here are
an important complement to existing data. In the LMC, these bright AGB stars
are centrally located, whereas they are concentrated in an active
star-formation ring in M31. In the SMC and M33, there are not enough of them to
draw definite conclusions, although they tend to be centrally located. Their
luminosity functions are similar for the four galaxies we studied.


title:
The Role of Single Stars of Low and Intermediate Mass in Galactic
  Chemical Evolution

abstract:
  A short overview is presented of the role that Low and Intermediate mass
stars play in Galactic Chemical Evolution; their action affects key elements
and isotopes, like deuterium, He-3, Li-7, carbon and nitrogen, and s-process
nuclei. In all those cases, critical uncertainties still remain and are briefly
discussed here.


title: Study of Very Short GRB: New Results from BATSE and KONUS

abstract:
  Our recent studies of Very Short Gamma Ray Bursts (VSB) of duration T_{90}
\le 100 ms have indicated a significant angular asymmetry and a uniform
V/V_{max} distribution from the BATSE data. Here we update these studies, and
we extend our research to events observed with KONUS satellite which gives a
new insight into the spectra not possible with the BATSE data. KONUS has
observed 18 events with T_{90} \le 100 ms duration. These events display
considerable numbers of photons with energies above 1 MeV and have photons
above 5 MeV in all cases. These appear to be some of the most energetic photons
observed from any classes of GRB to date.


title: Simulations of Axisymmetric Magnetospheres of Neutron Stars

abstract:
  In this paper we present the results of time-dependent simulations of dipolar
axisymmetric magnetospheres of neutron stars carried out both within the
framework of relativistic magnetohydrodynamics and within the framework of
resistive force-free electrodynamics. The results of force-free simulations
reveal the inability of our numerical method to accommodate the equatorial
current sheets of pulsar magnetospheres and raise a question mark over the
robustness of this approach. On the other hand, the MHD approach allows to make
a significant progress. We start with a nonrotating magnetically dominated
dipolar magnetospheres and follow its evolution as the stellar rotation is
switched on. We find that the time-dependent solution gradually approaches the
steady state that is very close to the stationary solution of the Pulsar
Equation found by Contopoulos et al.(1999). This result suggests that other
stationary solutions that have the y-point located well inside the light
cylinder are unstable. The role of the particle inertia and pressure on the
structure and dynamics of MHD magnetospheres is studied in details, as well as
the potential implications of the dissipative processes in the equatorial
current sheet. We argue that pulsars may have differentially rotating
magnetospheres which develop noticeable structural oscillations and that this
may help to explain the nature of the sub-pulse phenomena.


title:
The Ages of Globular Clusters in NGC 4365 Revisited with Deep HST
  Observations

abstract:
  We present new Hubble Space Telescope (HST)-NIC3, near-infrared H-band
photometry of globular clusters (GC) around NGC 4365 and NGC 1399 in
combination with archival HST-WCPC2 and ACS optical data. We find that NGC 4365
has a number of globular clusters with bluer optical colors than expected for
their red optical to near-infrared colors and an old age. The only known way to
explain these colors is with a significant population of intermediate-age (2-8
Gyr) clusters in this elliptical galaxy. In contrast, NGC 1399 reveals no such
population. Our result for NGC 1399 is in agreement with previous spectroscopic
work that suggests that its clusters have a large metallicity spread and are
nearly all old. In the literature, there are various results from spectroscopic
studies of modest samples of NGC 4365 globular clusters. The spectroscopic data
allow for either the presence or absence of a significant population of
intermediate-age clusters, given the index uncertainties indicated by comparing
objects in common between these studies and the few spectroscopic candidates
with optical to near-IR colors indicative of intermediate ages. Our new near-IR
data of the NGC 4365 GC system with much higher signal-to-noise agrees well
with earlier published photometry and both give strong evidence of a
significant intermediate-age component. The agreement between the photometric
and spectroscopic results for NGC 1399 and other systems lends further
confidence to this conclusion, and to the effectiveness of the near-IR
technique.


title:
The Connections between QSO Absorption Systems and Galaxies:
  Low-Redshift Observations

abstract:
  Quasar absorption lines have long been recognized to be a sensitive probe of
the abundances, physical conditions, and kinematics of gas in a wide variety of
environments including low-density intergalactic regions that probably cannot
be studied by any other means. While some pre-Hubble Space Telescope (HST)
observations indicated that Mg II absorption lines arise in gaseous galactic
halos with a large covering factor, many early QSO absorber studies were
hampered by a lack of information about the context of the absorbers and their
connections with galaxies. By providing access to crucial ultraviolet resonance
lines at low redshifts, deployment of HST and the Far Ultraviolet Spectroscopic
Explorer enabled detailed studies of the relationships between QSO absorbers
and galaxies. The advent of large surveys such as the Sloan Digital Sky Survey
(SDSS) has also advanced the topic by greatly improving the size of absorber
and galaxy samples. This paper briefly reviews some observational results on
absorber-galaxy connections that have been obtained in the HST/SDSS era,
including Mg II absorbers, the low-z Lyman alpha forest, Lyman limit and damped
Lyman alpha absorbers, and O VI systems.


title:
uvby-\beta photometry of high-velocity and metal-poor stars XI. Ages of
  halo and old disk stars

abstract:
  New uvby-\beta data are provided for 442 high-velocity and metal-poor stars;
90 of these stars have been observed previously by us, and 352 are new. When
combined with our previous two photometric catalogues, the data base is now
made up of 1533 high-velocity and metal-poor stars, all with uvby-\beta
photometry and complete kinematic data, such as proper motions and radial
velocities taken from the literature. Hipparcos, plus a new photometric
calibration for M_v also based on the Hipparcos parallaxes, provide distances
for nearly all of these stars; our previous photometric calibrations give
values for E(b-y) and [Fe/H]. The [Fe/H],V(rot) diagram allows us to separate
these stars into different Galactic stellar population groups, such as
old-thin-disk, thick-disk, and halo. The X histogram, where X is our
stellar-population discriminator combining V(rot) and [Fe/H], and contour plots
for the [Fe/H],V(rot) diagram both indicate two probable components to the
thick disk. These population groups and Galactic components are studied in the
(b-y)_o,M_v diagram, compared to the isochrones of Bergbusch & VandenBerg
(2001), to derive stellar ages. The two thick-disk groups have the mean
characteristics: ([Fe/H], V(rot), Age, \sigma_W') ~ (-0.7 dex, 120 km/s, 12.5
Gyr, 62.0 km/s), and ~(-0.4, 160, 10.0, 45.8). The seven most metal-poor halo
groups, -2.31 <= [Fe/H] <= -1.31, show a mean age of 13.0 +/-0.2 (mean error)
Gyr, giving a mean difference from the WMAP results for the age of the Universe
of 0.7 +/- 0.3 Gyr. These results for the ages and components of the thick disk
and for the age of the Galactic halo field stars are discussed in terms of
various models and ideas for the formation of galaxies and their stellar
populations.


title: Slow and fast components in the X-ray light curves of Gamma-Ray Bursts

abstract:
  Gamma-ray burst light curves show quite different patterns: from very simple
to extremely complex. We present a temporal and spectral study of the light
curves in three energy bands (2-5, 5-10, 10-26 keV) of ten GRBs detected by the
Wide Field Cameras on board BeppoSAX. For some events the time profiles are
characterized by peaks superposed on a slowly evolving pedestal, which in some
cases becomes less apparent at higher energies. We describe this behaviour with
the presence of two components (slow and fast) having different variability
time scales. We modelled the time evolution of slow components by means of an
analytical function able to describe asymmetric rising and decaying profiles.
The residual light curves, after the subtraction of the slow components,
generally show structures more similar to the original curves in the highest
energy band. Spectral study of these two components was performed evaluating
their hardness ratios, used also to derive photon indices. Slow components are
found generally softer than the fast ones suggesting that their origin is
likely different. Being typical photon indices lower than those of the
afterglows there is no evidence that the emission processes are similar.
Another interesting possibility is that slow components can be related to the
presence of a hot photosphere having a thermal spectrum with kT around a few
keV superposed to a rapid variable non-thermal emission of the fast component.


title: Two populations of progenitors for type Ia SNe?

abstract:
  We use recent observations of type Ia Supernova (SN Ia) rates to derive, on
robust empirical grounds, the distribution of the delay time (DTD) between the
formation of the progenitor star and its explosion as a SN. Our analysis finds:
i) delay times as long as 3-4 Gyr, derived from observations of SNe Ia at high
redshift, cannot reproduce the dependence of the SN Ia rate on the colors and
on the radio-luminosity of the parent galaxies, as observed in the local
Universe; ii) the comparison between observed SN rates and a grid of
theoretical "single-population" DTDs shows that only a few of them are possibly
consistent with observations. The most successful models are all predicting a
peak of SN explosions soon after star formation and an extended tail in the
DTD, and can reproduce the data but only at a modest statistical confidence
level; iii) present data are best matched by a bimodal DTD, in which about 50%
of type Ia SNe (dubbed "prompt" SN Ia) explode soon after their stellar birth,
in a time of the order of 10^8 years, while the remaining 50% ("tardy" SN Ia)
have a much wider distribution, well described by an exponential function with
a decay time of about 3 Gyr. This fact, coupled with the well established
bimodal distribution of the decay rate, suggests the existence of two classes
of progenitors. We discuss the cosmological implications of this result and
make simple predictions. [Abridged]


title: Stable magnetic fields in stellar interiors

abstract:
  We investigate the 50-year old hypothesis that the magnetic fields of the Ap
stars are stable equilibria that have survived in these stars since their
formation. With numerical simulations we find that stable magnetic field
configurations indeed appear to exist under the conditions in the radiative
interior of a star. Confirming a hypothesis by Prendergast (1956), the
configurations have roughly equal poloidal and toroidal field strengths. We
find that tori of such twisted fields can form as remnants of the decay of an
unstable random initial field. In agreement with observations, the appearance
at the surface is an approximate dipole with smaller contributions from higher
multipoles, and the surface field strength can increase with the age of the
star. The results of this paper were summarised by Braithwaite & Spruit (2004).


title: Generation of Emissions By Fast Particles In Stochastic Media

abstract:
  The review presents basic elements of the theory of electromagnetic emission
by nonthermal particles propagating in stochastic media. In particular, general
theory and a few special regimes of Diffusive Synchrotron Radiation
(DSR)arising in the presence of random magnetic/electric fields are analyzed in
detail. Possible applications of the DSR theory to astrophysical sources as
well as other emission processes typical for the random media are discussed
briefly.


title:
Variation in the luminosity of Kerr quasars due to extra dimension in
  brane Randall-Sundrum model

abstract:
  We propose an alternative theoretical approach showing how the existence of
an extra dimension in Randall-Sundrum model can estimate the correction in the
horizon of Schwarzschild and Kerr black holes, and consequently its
measurability in terms of the variation of quasar luminosity, which can be
caused by a imprint of an extra dimension endowing the geometry of a
brane-world scenario in an AdS5 bulk. The rotation effects cause a more
prominent correction in Kerr horizon radius than in Schwarzschild (static black
hole) radius, via brane-world effects, and the consequent bigger variation in
the luminosity in Kerr black holes quasars. This paper is intended to
investigate the variation of luminosity due to accretion of gas in
Schwarzschild and Kerr black holes (BHs) in the center of quasars, besides also
investigating the variation of luminosity in supermassive BHs by brane-world
effects, using Randall-Sundrum model.


title:
First VUV full-Sun spectrum of the transition region with high spectral
  resolution compared to cool stars

abstract:
  This paper reports the first full-Sun vacuum ultraviolet (VUV) emission line
profile originating from the transition region from the chromosphere to the
corona. It is based on a raster scan of the whole solar disk using SUMER/SOHO.
The full-Sun spectrum has a spectral resolution which allows an investigation
of details in the line profile as well as a thorough comparison to stellar
spectra as obtained, e.g. with FUSE or STIS/HST. The full-Sun spectrum shows
enhanced emission in the wings, and is well described by a double Gaussian fit
with a narrow and a broad component. It is shown that the broad component is
due to structures on the solar surface, especially those related to the
magnetic chromospheric network. Thus it is proposed that the broad components
of other solar-like stars are also a consequence of the mixture of surface
structures, and not necessarily a signature of small-scale heating processes
like explosive events, as it is commonly argued. A comparison to spectra of
luminous cool stars shows that the line asymmetries of these stars might also
be a surface structure effect and not or only partly due to opacity effects in
their cool dense winds. These comparisons show the potential of high quality
full-Sun VUV spectra and their value for the study of solar-stellar
connections. As an example, this study proposes that alpha Cen A has a
considerably higher amount of magnetic flux concentrated in the chromospheric
magnetic network than the Sun.


title:
The trigger system of the Pierre Auger Surface Detector: operation,
  efficiency and stability

abstract:
  The trigger system of the Surface Detector (SD) of the Pierre Auger
Observatory is described, from the identification of candidate showers ($E>1$
EeV) at the level of a single station, among a huge background (mainly single
muons), up to the selection of real events and the rejection of random
coincidences at a higher central trigger level (including the reconstruction
accuracy). Efficiency of a single station trigger is evaluated using real data
, and the high performance of event selection hierarchy will be demonstrated.


title: High-energy Cosmic Rays

abstract:
  After a brief review of galactic cosmic rays in the GeV to TeV energy range,
we describe some current problems of interest for particles of very high
energy. Particularly interesting are two features of the spectrum, the `knee'
above $10^{15}$ eV and the `ankle' above $10^{18}$ eV. An important question is
whether the highest energy particles are of extra-galactic origin and, if so,
at what energy the transition occurs. A theme common to all energy ranges is
use of nuclear abundances as a tool for understanding the origin of the cosmic
radiation.


title: A necessary extension of the surface flux transport model

abstract:
  Customary two-dimensional flux transport models for the evolution of the
magnetic field at the solar surface do not account for the radial structure and
the volume diffusion of the magnetic field. When considering the long-term
evolution of magnetic flux, this omission can lead to an unrealistic long-term
memory of the system and to the suppression of polar field reversals. In order
to avoid such effects, we propose an extension of the flux transport model by a
linear decay term derived consistently on the basis of the eigenmodes of the
diffusion operator in a spherical shell. A decay rate for each eigenmode of the
system is determined and applied to the corresponding surface part of the mode
evolved in the flux transport model. The value of the volume diffusivity
associated with this decay term can be estimated to be in the range 50--100
km^2/s by considering the reversals of the polar fields in comparison of flux
transport simulations with observations. We show that the decay term prohibits
a secular drift of the polar field in the case of cycles of varying strength,
like those exhibited by the historical sunspot record.


title: Analysis of the BATSE Continuous MER data

abstract:
  The CGRO/BATSE database includes many types of data such as the 16-channel
continuous background or medium energy resolution burst data (CONT and MER data
types). We have calculated some four hundred burst's medium energy resolution
spectra and Principal Component Analysis has been applied. We found five
components can describe GRBs' spectra.


title:
Looking for Light Pseudoscalar Bosons in the Binary Pulsar System
  J0737-3039

abstract:
  We present numerical calculations of the photon-light-pseudoscalar-boson
conversion in the recently discovered binary pulsar system J0737-3039. Light
pseudoscalar bosons (LPBs) oscillate into photons in the presence of strong
magnetic fields. In the context of this binary pulsar system, this phenomenon
attenuates the light beam emitted by one of the pulsars, when the light ray
goes through the magnetosphere of the companion pulsar. We show that such an
effect is observable in the gamma-ray band since the binary pulsar is seen
almost edge-on, depending on the value of the LPB mass and on the strenght of
its two-photon coupling. Our results are surprising in that they show a very
sharp and significant (up to 50%) transition probability in the gamma-ray ($>$
tens of MeV) domain. The observations can be performed by the upcoming NASA
GLAST mission.


title:
Infrared Properties of Star Forming Dwarf Galaxies: Blue Compact Dwarfs
  in the Virgo Cluster

abstract:
  A sample of 16 blue compact dwarf galaxies (BCDs) in the Virgo Cluster has
been imaged in the near-infrared (NIR) in $J$ and $K_s$ on the 2.1m telescope
at OAN-SPM in Mexico. Isophotes as faint as $\mu_J$ = 24 mag arcsec$^{-2}$ and
$\mu_{K_s}$ = 23 mag arcsec$^{-2}$ have been reached in most of the targets.
Surface brightness profiles can be fitted across the whole range of radii by
the sum of two components: a hyperbolic secant (sech) function, which is known
to fit the light profiles of dIs, and a Gaussian component, which quantifies
the starburst near the centre. Isophotal and total fitted NIR magnitudes have
been calculated, along with semimajor axes at $\mu_J$ = 23 mag arcsec$^{-2}$
and $\mu_{K_s}$ = 22 mag arcsec$^{-2}$. The diffuse underlying component and
the young starburst have been quantified using the profile fitting. Most color
profiles show a constant color, between $J-K_s$=0.7 to 0.9 mag. The diffuse
component represents the overwhelming majority of the NIR light for most BCDs,
the starburst enhancing the flux by less than about 0.3 mag. Linear
correlations were found between the sech scale length and the sech magnitude,
and between the sech semimajor axis and the sech magnitude. Overall, galaxies
with more luminous diffuse components are larger and brighter in the centre.
The central burst correlates with the diffuse component, with brighter BCDs
having stronger star-bursts, suggesting that more massive objects are forming
stars more efficiently. BCDs lie on the ``fundamental plane'' defined by dwarf
irregulars (dISs) in Paper I, following the same relation between sech absolute
magnitude, sech central surface brightness, and the hydrogen line-width
$W_{20}$, although the scatter is larger than for the dIs. [one sentence cut]


title:
Asteroseismology of the Beta Cephei star 12 (DD) Lacertae: photometric
  observations, pulsational frequency analysis and mode identification

abstract:
  We report a multisite photometric campaign for the Beta Cephei star 12
Lacertae. 750 hours of high-quality differential photoelectric Stromgren,
Johnson and Geneva time-series photometry were obtained with 9 telescopes
during 190 nights. Our frequency analysis results in the detection of 23
sinusoidal signals in the light curves. Eleven of those correspond to
independent pulsation modes, and the remainder are combination frequencies. We
find some slow aperiodic variability such as that seemingly present in several
Beta Cephei stars. We perform mode identification from our colour photometry,
derive the spherical degree l for the five strongest modes unambiguously and
provide constraints on l for the weaker modes. We find a mixture of modes of 0
<= l <= 4. In particular, we prove that the previously suspected rotationally
split triplet within the modes of 12 Lac consists of modes of different l;
their equal frequency splitting must thus be accidental.
  One of the periodic signals we detected in the light curves is argued to be a
linearly stable mode excited to visible amplitude by nonlinear mode coupling
via a 2:1 resonance. We also find a low-frequency signal in the light
variations whose physical nature is unclear; it could be a parent or daughter
mode resonantly coupled. The remaining combination frequencies are consistent
with simple light-curve distortions.
  The range of excited pulsation frequencies of 12 Lac may be sufficiently
large that it cannot be reproduced by standard models. We suspect that the star
has a larger metal abundance in the pulsational driving zone, a hypothesis also
capable of explaining the presence of Beta Cephei stars in the LMC.


title:
Galaxy Pairs in cosmological simulations: Effects of interactions on
  star formation

abstract:
  We carried out a statistical analysis of galaxy pairs in hydrodynamical
Lambda-CDM simulations. We focused on the triggering of star formation by
interactions and analysed the enhancement of star formation activity in terms
of orbital parameters. By comparing to a suitable sample of simulated galaxies
without a nearby companion, we find that close encounters (r<30 kpc/h) may
effectively induce star formation. However, our results suggest that the
stability properties of systems and the spatial proximity are both relevant
factors in the process of triggering star formation by tidal interactions. In
order to assess the effects of projection and spurious pairs in observational
samples, we also constructed and analysed samples of pairs of galaxies in the
simulations obtained in projection. We found a good agreement with
observational results with a threshold at rp ~ 25 kpc/h for interactions to
effectively enhance star formation activity.
  For pairs within rp < 100 kpc/h, we estimated a ~27% contamination by
spurious pairs, reduced to ~19% for close systems. We also found that spurious
pairs affect more strongly high density regions with 17% of spurious pairs
detected for low density regions compared to 33% found in high density ones.
Also, we analysed the dependence of star formation on environment by defining
the usual projected density parameter for both pairs and isolated galaxies in
the simulations. We find the expected star formation-local density relation for
both galaxies in pairs and without a close companion, with a stronger density
dependence for close pairs which suggests a relevant role for interactions in
driving this relation.


title: Scaling of voids in the large scale distribution of matter

abstract:
  Voids are a prominent feature of the galaxy distribution but their
quantitative study is hindered by the lack of a precise definition of what
constitutes a void. Here we propose a definition of voids in point
distributions that uses methods of discrete stochastic geometry, in particular,
Delaunay and Voronoi tessellations, and we construct a new void-finder. We then
apply the void-finder to scaling point distributions. First, we find the voids
of pure fractals with a transition to homogeneity and show that the rank
ordering of the voids also scales (Zipf's law) and, in addition, shows the
transition to homogeneity. However, a pure fractal is arguably not a good model
of the galaxy distribution, so we construct from a cosmological $N$-body
simulation a bifractal mock galaxy sample representing two galaxy populations,
which we identify as "wall" and "field" galaxies. The wall galaxy distribution
fits a pure fractal with a transition to homogeneity and, furthermore, the rank
ordering of its voids shows a scaling range with the right slope plus a
transition to homogeneity.


title: Low-Intensity States in the Neutron Star X-ray Binary Aql X-1

abstract:
  Aql X-1 was observed in a Low Intensity State (LIS), a state that is usually
characterized by high optical but low X-ray flux. Our daily monitoring of the
source using the 1.3m telescope in Cerro Tololo Inter-America Observatory
operated by the Small and Moderate Aperture Research Telescope System (SMARTS)
was used to trigger a series of target-of-opportunity (ToO) observations of the
source using the Rossi X-ray Timing Explorer satellite (RXTE). The X-ray colors
and temporal variability studies suggest that the source was in a powerlaw
dominated state featuring high rms variability in the lightcurve and dominance
of hard photons during this LIS. The ToO observations were continued until the
source made a transition to the canonical thermal dominated or high/soft state.


title:
The Relationship Between Baryons and Dark Matter in Extended Galaxy
  Halos

abstract:
  The relationship between gas-rich galaxies and Ly-alpha absorbers is
addressed in this paper in the context of the baryonic content of galaxy halos.
Deep Arecibo HI observations are presented of two gas-rich spiral galaxies
within 125 kpc projected distance of a Ly-alpha absorber at a similar velocity.
The galaxies investigated are close to edge-on and the absorbers lie almost
along their major axes, allowing for a comparison of the Ly-alpha absorber
velocities with galactic rotation. This comparison is used to examine whether
the absorbers are diffuse gas rotating with the galaxies' halos, outflow
material from the galaxies, or intergalactic gas in the low redshift cosmic
web. The results indicate that if the gas resides in the galaxies' halos it is
not rotating with the system and possibly counter-rotating. In addition, simple
geometry indicates the gas was not ejected from the galaxies and there are no
gas-rich satellites detected down to 3.6 - 7.5 x 10^6 Msun, or remnants of
satellites to 5-6 x 10^{18} cm^{-2}. The gas could potentially be infalling
from large radii, but the velocities and distances are rather high compared to
the high velocity clouds around the Milky Way. The most likely explanation is
the galaxies and absorbers are not directly associated, despite the vicinity of
the spiral galaxies to the absorbers (58-77 kpc from the HI edge). The spiral
galaxies reside in a filament of intergalactic gas, and the gas detected by the
absorber has not yet come into equilibrium with the galaxy. These results also
indicate that the massive, extended dark matter halos of spiral galaxies do not
commonly have an associated diffuse baryonic component at large radii.


title:
Detection of a period decrease in NN Ser with ULTRACAM: evidence for
  strong magnetic braking or an unseen companion?

abstract:
  We present results of high time resolution photometry of the eclipsing
pre-cataclysmic variable NN Ser. We observed 13 primary eclipses of NN Ser
using the high-speed CCD camera ULTRACAM and derived times of mid-eclipse, from
fitting of light curve models, with uncertainties as low as 0.06 s. The
observed rates of period change appear difficult to reconcile with any models
of orbital period change. If the observed period change reflects an angular
momentum loss, the average loss rate is consistent with the loss rates (via
magnetic stellar wind braking) used in standard models of close binary
evolution, which were derived from observations of much more massive cool
stars. Observations of low-mass stars such as NN Ser's secondary predict rates
of ~100 times lower than we observe. We show that magnetic activity-driven
changes in the quadrupole moment of the secondary star (Applegate, 1992) fail
to explain the period change by an order of magnitude on energetic grounds, but
that a light travel time effect caused by the presence of a third body in a
long (~ decades) orbit around the binary could account for the observed changes
in the timings of NN Ser's mid-eclipses. We conclude that we have either
observed a genuine angular momentum loss for NN Ser, in which case our
observations pose serious difficulties for the theory of close binary
evolution, or we have detected a previously unseen low-mass companion to the
binary.


title:
Density Profiles of Collisionless Equilibria. I. Spherical Isotropic
  Systems

abstract:
  We investigate the connection between collisionless equilibria and the
phase-space relation between density $\rho$ and velocity dispersion $\sigma$
found in simulations of dark matter halo formation, $F=\psd \propto
r^{-\alpha}$. Understanding this relation will shed light on the physics
relevant to collisionless collapse and on the subsequent structures formed. We
show that empirical density profiles that provide good fits to N-body halos
also happen to have nearly scale-free \psd distributions when in equilibrium.
We have also done a preliminary investigation of variables other than $r$ that
may match or supercede the correlation with $F$. In the same vein, we show that
$\rho/\sigma^m$, where $m=3$ is the most appropriate combination to use in
discussions of the power-law relationship. Since the mechanical equilibrium
condition that characterizes the final systems does not by itself lead to
power-law $F$ distributions, our findings prompt us to posit that dynamical
collapse processes (such as violent relaxation) are responsible for the radial
power-law nature of the \psd distributions of virialized systems.


title:
The contrast of magnetic elements in synthetic CH- and CN-band images of
  solar magnetoconvection

abstract:
  We present a comparative study of the intensity contrast in synthetic CH-band
and violet CN-band filtergrams computed from a high-resolution simulation of
solar magnetoconvection. The underlying simulation has an average vertical
magnetic field of 250 G with kG fields concentrated in its intergranular lanes,
and is representative of a plage region. To simulate filtergrams typically
obtained in CH- and CN-band observations we computed spatially resolved spectra
in both bands and integrated these spectra over 1 nm FWHM filter functions
centred at 430.5 nm and 388.3 nm, respectively. We find that the average
contrast of magnetic bright points in the simulated filtergrams is lower in the
CN-band by a factor of 0.96. This result strongly contradicts earlier
semi-empirical modeling and recent observations, which both etimated that the
bright-point contrast in the CN-band is \emph{higher} by a factor of 1.4. We
argue that the near equality of the bright-point contrast in the two bands in
the present simulation is a natural consequence of the mechanism that causes
magnetic flux elements to be particularly bright in the CN and CH filtergrams,
namely the partial evacuation of these elements and the concomitant weakening
of molecular spectral lines in the filter passbands. We find that the RMS
intensity contrast in the whole field-of-view of the filtergrams is 20.5% in
the G band and 22.0% in the CN band and conclude that this slight difference in
contrast is caused by the shorter wavelength of the latter. Both the
bright-point and RMS intensity contrast in the CN band are sensitive to the
precise choice of the central wavelength of the filter.


title: Radio Astronomical Polarimetry and High-Precision Pulsar Timing

abstract:
  A new method of matrix template matching is presented in the context of
pulsar timing analysis. Pulse arrival times are typically measured using only
the observed total intensity light curve. The new technique exploits the
additional timing information available in the polarization of the pulsar
signal by modeling the transformation between two polarized light curves in the
Fourier domain. For a number of millisecond pulsars, arrival time estimates
derived from polarimetric data are predicted to exhibit greater precision and
accuracy than those derived from the total intensity alone. Furthermore, the
transformation matrix produced during template matching may be used to
calibrate observations of other point sources. Unpublished supplementary
material is appended after the bibliography.


title:
Dissipation of Magnetohydrodynamic Waves on Energetic Particles: Impact
  on Interstellar Turbulence and Cosmic Ray Transport

abstract:
  The physical processes involved in diffusion of Galactic cosmic rays in the
interstellar medium are addressed. We study the possibility that the nonlinear
MHD cascade sets the power-law spectrum of turbulence which scatters charged
energetic particles. We find that the dissipation of waves due to the resonant
interaction with cosmic ray particles may terminate the Kraichnan-type cascade
below wavelengths 10^13 cm. The effect of this wave dissipation has been
incorporated in the GALPROP numerical propagation code in order to asses the
impact on measurable astrophysical data. The energy-dependence of the
cosmic-ray diffusion coefficient found in the resulting self-consistent model
may explain the peaks in the secondary to primary nuclei ratios observed at
about 1 GeV/nucleon.


title: Probing for Leptonic Signatures from GRB030329 with AMANDA-II

abstract:
  The discovery of high-energy (TeV-PeV) neutrinos from gamma-ray bursts (GRBs)
would shed light on their intrinsic microphysics by confirming hadronic
acceleration in the relativistic jet; possibly revealing an acceleration
mechanism for the highest energy cosmic rays. We describe an analysis featuring
three models based upon confronting the fireball phenomenology with
ground-based and satellite observations of GRB030329, which triggered the High
Energy Transient Explorer (HETE-II). Contrary to previous diffuse searches, the
expected discrete muon neutrino energy spectra for models 1 and 2, based upon
an isotropic and beamed emission geometry, respectively, are directly derived
from the fireball description of the prompt gamma-ray photon energy spectrum,
whose spectral fit parameters are characterized by the Band function, and the
spectroscopically observed redshift, based upon the associated optical
transient (OT) afterglow. For comparison, we also consider a model (3) based
upon averaged burst parameters and isotropic emission. Strict spatial and
temporal constraints (based upon electromagnetic observations), in conjunction
with a single, robust selection criterion (optimized for discovery) have been
leveraged to realize a nearly background-free search, with nominal signal loss,
using archived data from the Antarctic Muon and Neutrino Detector Array
(AMANDA-II). Our preliminary results are consistent with a null signal
detection, with a peak muon neutrino effective area of ~80 m^2 at ~2 PeV and a
flux upper limit of ~0.150 GeV/cm^2/s for model 1. Predictions for IceCube,
AMANDA's kilometer scale successor, are compared with those found in the
literature. Implications for correlative searches are discussed


title: Radial Velocity Variations in K Giants: Planets or Pulsations?

abstract:
  Radial velocity observations of K giants have revealed periodic variations
for some of the stars. The periods range from approximately 180 to 1000 or more
days with velocity amplitudes ranging from approximately 50 m/s to 500 m/s.
Except for Iota Draconis (Frink et al. (2002)), all variations are nearly
sinusoidal. Companions with zero orbital eccentricity as well as pulsations may
cause these radial velocity variations. Additional high resolution spectra were
taken in order to reveal which of these mechanisms is at work. No conclusions
can be drawn from this work yet, although it seems likely that at least for
some stars pulsations are the best explanation. A theoretical study is
performed to investigate what kind of pulsations could cause these long period
radial velocity variations.


title:
Is the INTEGRAL/IBIS source IGR J17204-3554 a gamma-ray emitting galaxy
  hidden behind the molecular cloud NGC 6334 ?

abstract:
  We report on the identification of a soft gamma-ray source, IGR J17204-3554,
detected with the IBIS imager on board the INTEGRAL satellite. The source has a
20-100 keV flux of ~3x10^-11 erg cm^-2 s^-1 and is spatially coincident with
NGC 6334, a molecular cloud located in the Sagittarius arm of the Milky Way.
Diffuse X-ray emission has been reported from this region by ASCA and
interpreted as coming from five far-infrared cores located in the cloud.
However, the combined ASCA spectrum with a 9 keV temperature was difficult to
explain in terms of emission from young pre-main sequence stars known to be
embedded in the star forming regions. Detection of gamma-rays makes this
interpretation even more unrealistic and suggests the presence of a high energy
source in or behind the cloud. Follow up observations with Swift and archival
Chandra data allow us to disentangle the NGC6334 enigma by locating an
extragalactic object with the proper spectral characteristics to explain the
gamma-ray emission. The combined Chandra/IBIS spectrum is well fitted by an
absorbed power law with index 1.2+/-0.1, NH=1.4+/-0.1x10^23 cm^-2 and an
unabsorbed 2-10 keV flux of 0.5x10^-11 erg cm^-2 s^-1. This column density is
in excess of the galactic value implying that we are detecting a background
galaxy concealed by the molecular cloud and further hidden by material located
either in the galaxy itself or between IGR J17204-3554 and the cloud.


title:
The evolution of the luminosity functions in the FORS Deep Field from
  low to high redshift: II. The red bands

abstract:
  We present the redshift evolution of the restframe galaxy luminosity function
(LF) in the red r', i', and z' bands as derived from the FORS Deep Field (FDF).
Using the deep and homogeneous I-band selected dataset of the FDF we are able
to follow the red LFs over the redshift range 0.5 < z < 3.5. The results are
based on photometric redshifts for 5558 galaxies derived from the photometry in
9 filters achieving an accuracy of Delta z / (z_spec+1) ~ 0.03 with only ~ 1 %
outliers. Because of the depth of the FDF we can give relatively tight
constraints on the faint-end slope alpha of the LF: The faint-end of the red
LFs does not show a large redshift evolution and is compatible within 1 sigma
to 2 sigma with a constant slope over the redshift range 0.5 < z < 2.0.
Moreover, the slopes in r', i', and z' are very similar with a best fitting
value of alpha= -1.33 +- 0.03 for the combined bands. There is a clear trend of
alpha to steepen with increasing wavelength: alpha_(UV & u')=-1.07 +- 0.04 ->
alpha_(g' & B)=-1.25 +- 0.03 -> alpha_(r' & i' & z')=-1.33 +- 0.03. We show
that the wavelength dependence of the LF slope can be explained by the relative
contribution of different SED-type LFs to the overall LF, as different SED
types dominate the LF in the blue and red bands. Furthermore we also derive and
analyze the luminosity density evolution of the different SED types up to z ~
2. Based on the FDF data, we find only a mild brightening of M_star and
decrease of phi_star with increasing redshift. Therefore, from <z> ~ 0.5 to <z>
\~ 3 the characteristic luminosity increases by ~0.8, ~0.4 and ~0.4 magnitudes
in the r', i', and z' bands, respectively. Simultaneously the characteristic
density decreases by about 40 % in all analyzed wavebands. [abridged]


title: The broad-band spectrum of Cyg X-2 with INTEGRAL

abstract:
  We study the broad band (3-100 keV) spectrum of Cygnus X-2 with INTEGRAL. We
find that the spectrum is well fitted by a Comptonized component with a
seed-photons temperature of ~1 keV, an electron temperature of ~3 keV and an
optical depth tau ~ 8. Assuming spherical geometry, the radius of the
seed-photons emitting region is ~17 km. The source shows no hard X-ray
emission; it was detected only at a 3 sigma level above 40 keV. We also
analyzed public ISGRI data of Cyg X--2 to investigate the presence of a hard
X-ray component. We report the possible presence of hard X-ray emission in one
data set.


title: Accessibility of the Pre-Big-Bang Models to LIGO

abstract:
  The recent search for a stochastic background of gravitational waves with
LIGO interferometers has produced a new upper bound on the amplitude of this
background in the 100 Hz region. We investigate the implications of the current
and future LIGO results on pre-Big-Bang models of the early Universe,
determining the exclusion regions in the parameter space of the minimal pre-Big
Bang scenario. Although the current LIGO reach is still weaker than the
indirect bound from Big-Bang nucleosynthesis, future runs by LIGO, in the
coming year, and by Advanced LIGO (~2009) should further constrain the
parameter space, and in some parts surpass the Big-Bang nucleosynthesis bound.
It will be more diffcult to constrain the parameter space in non-minimal
pre-Big-Bang models, which are characterized by multiple cosmological phases in
the yet not well understood stringy phase, and where the higher-order curvature
and/or quantum-loop corrections in the string effective action should be
included.


title:
The ratio of N(C18O) and Av in Chamaeleon I and III-B using 2MASS and
  SEST

abstract:
  We investigate the relationship between the C18O column density and the
visual extinction in Chamaeleon I and in a part of the Chamaeleon III molecular
cloud. The C18O column densities, N(C18O), are calculated from J=1-0 rotational
line data observed with the SEST telescope. The visual extinctions, Av, are
derived using JHK photometry from the 2MASS survey and the NICER color excess
technique. In contrast with the previous results of Hayakawa et al. (2001), we
find that the average N(C18O) / Av ratios are similar in Cha I and Cha III, and
lie close to values derived for other clouds, i.e. N(C18O) ~ 2 x 10^14 cm^-2
(Av - 2). We find, however, clear deviations from this average relationship
towards individual clumps. Larger than average N(C18O) / Av ratios can be found
in clumps associated with the active star forming region in the northern part
of Ch a I. On the other hand, some regions in the relatively quiescent southern
part of Cha I show smaller than average N(C18O) / Av ratios and also very
shallow proportionality between N(C18O) and Av. The shallow proportionality
suggests that C18O is heavily depleted in these regions. As the degree of
depletion is proportional to the gas density, these regions probably contain
very dense, cold cores, which do not stand out in CO mappings. A comparison
with the dust temperature map derived from the ISO data shows that the most
prominent of the potentially depleted cores indeed coincides with a dust
temperature minimum. It seems therefore feasible to use N(C18O) and Av data
together for identifying old, dense cores in large scale mappings.


title:
Reddening distribution across the center of the globular cluster Omega
  Centauri

abstract:
  We present new medium-band uvby Stromgren and broad-band VI photometry for
the central regions of the globular cluster Omega Cen. From this photometry we
have obtained differential reddening estimates relative to two other globular
clusters (M13 and NGC288) using a metallicity-independent, reddening-free
temperature index, [c]=(u-v)-(v-b) - 0.2(b-y), for hot horizontal-branch (HB)
stars (T_e> 8,500K). We estimate color excesses of these hot HB stars using
optical and near-infrared colors, and find clumpy extinction variations of
almost a factor of two within the area of the cluster core. In particular, the
greatest density of more highly reddened objects appears to be shifted along
the right ascension axis when compared with less reddened ones. These findings
complicate photometric efforts to investigate the star formation history of
Omega Cen.


title: Pulsating Components in Close Binaries

abstract:
  We present an overview of pulsating stars in close binaries, focusing on the
question what role the dupliticity plays in triggering and/or modifying stellar
oscillations and on how it can help us to interpret the oscillatory behaviour
of (one of) the components. We give examples of characteristic types of
oscillations observed in binaries: forced oscillations and free oscillations in
both, short- and long-period binaries. The importance of studies of
oscillations in eclipsing binaries is also pointed out. A list of line-profile
and rapid light variables in close binaries with their basic properties is
provided. No obvious relations among the orbital eccentricity, orbital
frequency, rotational frequency and intrinsic frequencies of oscillations were
found. The value and future prospects of asteroseismic studies of binary stars
are briefly outlined while the complexity of the problem and its possible
complications are also discussed.


title:
The Geometric Calibration of the Planck satellite using point-source
  observations

abstract:
  The geometric calibration of the Planck satellite is investigated,
specifically those parameters which require the use of the science data for
their extraction. Methods for the recovery of these geometric-calibration
parameters from point source detections in the science data are presented,
together with the accuracies which may be achieved. These methods apply to the
a posteriori evaluation of these parameters using all the mission data, and may
be incorporated into the initial stages of the construction of the Planck final
compact source catalogue. It is found that this process achieves the pointing
requirements, provided that the geometric-calibration parameters vary only
slowly in time. Indeed the errors in the pointing reconstruction due to the
geometric calibration parameters may be seen to approach those due to the star
tracker.