596 research outputs found
The PASTEL catalogue of stellar parameters
The PASTEL catalogue is an update of the [Fe/H] catalogue, published in 1997
and 2001. It is a bibliographical compilation of stellar atmospheric parameters
providing (Teff,logg,[Fe/H]) determinations obtained from the analysis of high
resolution, high signal-to-noise spectra, carried out with model atmospheres.
PASTEL also provides determinations of the one parameter Teff based on various
methods. It is aimed in the future to provide also homogenized atmospheric
parameters and elemental abundances, radial and rotational velocities. A web
interface has been created to query the catalogue on elaborated criteria.
PASTEL is also distributed through the CDS database and VizieR. To make it as
complete as possible, the main journals have been surveyed, as well as the CDS
database, to find relevant publications. The catalogue is regularly updated
with new determinations found in the literature. As of Febuary 2010, PASTEL
includes 30151 determinations of either Teff or (Teff,logg,[Fe/H]) for 16649
different stars corresponding to 865 bibliographical references. Nearly 6000
stars have a determination of the three parameters (Teff,logg,[Fe/H]) with a
high quality spectroscopic metallicity.Comment: 5 pages, accepted for publication in A&A. The PASTEL catalogue can be
queried at http://pastel.obs.u-bordeaux1.fr/ or
http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/paste
M2000 : an astrometric catalog in the Bordeaux Carte du Ciel zone +11 degrees < {delta} < +18 degrees
During four years, systematic observations have been conducted in drift scan
mode with the Bordeaux automated meridian circle in the declination band [+11 ;
+18]. The resulting astrometric catalog includes about 2 300 000 stars down to
the magnitude limit V_M=16.3. Nearly all stars (96%) have been observed at
least 6 times, the catalog being complete down to V_M=15.4. The median internal
standard error in position is about 35 mas in the V_M magnitude range [11 ;
15], which degrades to about 50 mas when the faintest stars are considered.
M2000 provides also one band photometry with a median internal standard error
of 0.04 mag. Comparisons with the Hipparcos and bright part of Tycho-2 catalogs
have enabled to estimate external errors in position to be lower than 40 mas.
In this zone and at epoch 1998, the faint part of Tycho-2 is found to have an
accuracy of 116 mas in alpha instead of 82 mas deduced from the model-based
standard errors given in the catalog.Comment: The catalogue can be fetched directly from:
ftp://cdsarc.u-strasbg.fr/cats/I/272 or queried from:
http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/272 More information at :
http://www.observ.u-bordeaux.fr/~soubiran/m2000.ht
Multiwavelength Observations of 1ES 1959+650, One Year After the Strong Outburst of 2002
In April-May 2003, the blazar 1ES 1959+650 showed an increased level of X-ray
activity. This prompted a multiwavelength observation campaign with the Whipple
10 m gamma-ray telescope, the Rossi X-ray Timing Explorer, the Bordeaux Optical
Observatory, and the University of Michigan Radio Astrophysical Observatory. We
present the multiwavelength data taken from May 2, 2003 to June 7, 2003 and
compare the source characteristics with those measured during observations
taken during the years 2000 and 2002. The X-ray observations gave a data set
with high signal-to-noise light curves and energy spectra; however, the
gamma-ray observations did not reveal a major TeV gamma-ray flare. Furthermore,
we find that the radio and optical fluxes do not show statistically significant
deviations from those measured during the 2002 flaring periods. While the X-ray
flux and X-ray photon index appear correlated during subsequent observations,
the apparent correlation evolved significantly between the years 2000, 2002,
and 2003. We discuss the implications of this finding for the mechanism that
causes the flaring activity.Comment: 17 pages, 6 figures, 2 table
Xq27 FRAXA locus is a strong candidate for dyslexia: evidence from a genome-wide scan in French families.
Dyslexia is a frequent neurodevelopmental
learning disorder. To date, nine susceptibility loci have
been identified, one of them being DYX9, located in Xq27.
We performed the first French SNP linkage study followed
by candidate gene investigation in dyslexia by studying 12
multiplex families (58 subjects) with at least two children
affected, according to categorical restrictive criteria for
phenotype definition. Significant results emerged on
Xq27.3 within DYX9. The maximum multipoint LOD
score reached 3,884 between rs12558359 and rs454992.
Within this region, seven candidate genes were investigated
for mutations in exonic sequences (CXORF1,
CXORF51, SLITRK2, FMR1, FMR2, ASFMR1, FMR1NB),
all having a role during brain development. We further
looked for 50
UTR trinucleotide repeats in FMR1 and FMR2
genes. No mutation or polymorphism co-segregating with
dyslexia was found. This finding in French families with
Dyslexia showed significant linkage on Xq27.3 enclosing
FRAXA, and consequently confirmed the DYX9 region as
a robust susceptibility locus. We reduced the previously
described interval from 6.8 (DXS1227–DXS8091) to 4 Mb
also disclosing a higher LOD score
Astrometric suitability of optically-bright ICRF sources for the alignment with the future Gaia celestial reference frame
The ICRF, currently based on the position of 717 extragalactic radio sources
observed by VLBI, is the fundamental celestial reference frame adopted by the
IAU in 1997. Within the next 10 years, the European space astrometry mission
Gaia, to be launched by 2011, will permit determination of the extragalactic
reference frame directly in the visible for the first time. Aligning these two
frames with the highest accuracy will therefore be very important in the future
for ensuring consistency between the measured radio and optical positions. This
paper is aimed at evaluating the current astrometric suitability of the
individual ICRF radio sources which are considered appropriate for the
alignment with the future Gaia frame. To this purpose, we cross-identified the
ICRF and the optical catalog V\'eron-Cetty and V\'eron (2006), to identify the
optically-bright ICRF sources that will be positioned with the highest accuracy
with Gaia. Then we investigated the astrometric suitability of these sources by
examining their VLBI brightness distribution. We identified 243 candidate ICRF
sources for the alignment with the Gaia frame (with an optical counterpart
brighter than the apparent magnitude 18), but only 70 of these (10% of the ICRF
sources) are found to have the necessary high astrometric quality (i.e. a
brightness distribution that is compact enough) for this link. Additionally, it
was found that the QSOs that will have the most accurate positions in the Gaia
frame tend to have less-accurate VLBI positions, most probably because of their
physical structures. Altogether, this indicates that identifying other
high-quality VLBI radio sources suitable for the alignment with the future Gaia
frame is mandatory.Comment: To be published in A&A (2008)
An accurate distance to 2M1207Ab
In April 2004 the first image was obtained of a planetary mass companion (now
known as 2M1207 b) in orbit around a self-luminous object different from our
own Sun (the young brown dwarf 2MASSW J1207334-393254, hereafter 2M1207 A).
2M1207 b probably formed via fragmentation and gravitational collapse, offering
proof that such a mechanism can form bodies in the planetary mass regime.
However, the predicted mass, luminosity, and radius of 2M1207 b depend on its
age, distance, and other observables such as effective temperature. To refine
our knowledge of the physical properties of 2M1207 b and its nature, we
obtained an accurate determination of the distance to the 2M1207 A and b system
by measurements of its trigonometric parallax at the milliarcsec level. With
the ESO NTT/SUSI2 telescope, in 2006 we began a campaign of photometric and
astrometric observations to measure the trigonometric parallax of 2M1207 A. An
accurate distance ( pc) to 2M1207A was measured. From distance and
proper motions we derived spatial velocities fully compatible with TWA
membership. With this new distance estimate, we discuss three scenarios
regarding the nature of 2M1207 b: (1) a cool ( K) companion of mass
M, (2) a warmer ( K) and heavier (
M) companion occulted by an edge-on circum-secondary disk or (3) a
hot protoplanet collision afterglow.Comment: 5 pages, 3 figures, accepted for publication as letter in A&A,
6/11/200
Kinematic parameters and membership probabilities of open clusters in the Bordeaux PM2000 catalogue
We derive lists of proper-motions and kinematic membership probabilities for
49 open clusters and possible open clusters in the zone of the Bordeaux PM2000
proper motion catalogue (). We test
different parametrisations of the proper motion and position distribution
functions and select the most successful one. In the light of those results, we
analyse some objects individually. The segregation between cluster and field
member stars, and the assignment of membership probabilities, is accomplished
by applying a new and fully automated method based on both parametrisations of
the proper motion and position distribution functions, and genetic algorithm
optimization heuristics associated with a derivative-based hill climbing
algorithm for the likelihood optimization. We present a catalogue comprising
kinematic parameters and associated membership probability lists for 49 open
clusters and possible open clusters in the Bordeaux PM2000 catalogue region. We
note that this is the first determination of proper motions for five open
clusters. We confirm the non-existence of two kinematic populations in the
region of 15 previously suspected non-existent objects.Comment: 14 pages, 6 figures, 4 tables. Accepted for publication in Astronomy
& Astrophysic
HPV type concordance in sexual couples determines the effect of condoms on regression of flat penile lesions
We earlier demonstrated, in a randomised clinical trial, that the regression time of flat penile lsions in male sexual partners of women with cervical intraepithelial neoplasia (CIN) was shorter in men who used condoms compared to those who did not. To further evaluate this finding, we examined whether the effect of condom use on the regression of flat penile lesions depends on the presence of human papillomavirus (HPV) type concordance in sexual couples, as determined in cervical and penile scrapes by GP5+/6+ PCR testing. A Cox model with time-dependent covariates showed a beneficial effect of condoms on regression of flat penile lesions in concordant couples (hazard ratio 2.63, 95% CI 1.07–6.48) but not in those who were nonconcordant. When both partners harboured different HPV types, no effect of condoms was found (hazard ratio 0.90, 95% CI 0.27–2.96). Delayed regression of flat penile lesions was associated with either stable lesions or with new penile lesions developing at sites surrounding pre-existing lesions suggesting reinfection of the penile epithelium. We conclude that condom use blocks sexual HPV transmission by preventing reinfection and development of new penile lesions in men who are susceptible to the same type as present in the female partner
The correlated optical and radio variability of BL Lacertae. WEBT data analysis 1994-2005
Since 1997, BL Lacertae has undergone a phase of high optical activity, with
the occurrence of several prominent outbursts. Starting from 1999, the Whole
Earth Blazar Telescope (WEBT) consortium has organized various multifrequency
campaigns on this blazar, collecting tens of thousands of data points. One of
the main issues in the study of this huge dataset has been the search for
correlations between the optical and radio flux variations, and for possible
periodicities in the light curves. The analysis of the data assembled during
the first four campaigns (comprising also archival data to cover the period
1968-2003) revealed a fair optical-radio correlation in 1994-2003, with a delay
of the hard radio events of ~100 days. Moreover, various statistical methods
suggested the existence of a radio periodicity of ~8 years. In 2004 the WEBT
started a new campaign to extend the dataset to the most recent observing
seasons, in order to possibly confirm and better understand the previous
results. In this campaign we have collected and assembled about 11000 new
optical observations from twenty telescopes, plus near-IR and radio data at
various frequencies. Here, we perform a correlation analysis on the long-term
R-band and radio light curves. In general, we confirm the ~100-day delay of the
hard radio events with respect to the optical ones, even if longer (~200-300
days) time lags are also found in particular periods. The radio
quasi-periodicity is confirmed too, but the "period" seems to progressively
lengthen from 7.4 to 9.3 years in the last three cycles. The optical and radio
behaviour in the last forty years suggests a scenario where geometric effects
play a major role. In particular, the alternation of enhanced and suppressed
optical activity (accompanied by hard and soft radio events, respectively) canComment: 6 pages, 4 figure
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