910 research outputs found
2003--2005 INTEGRAL and XMM-Newton observations of 3C 273
The aim of this paper is to study the evolution of the broadband spectrum of
one of the brightest and nearest quasars 3C 273.
We analyze the data obtained during quasi-simultaneous INTEGRAL and XMM
monitoring of the blazar 3C 273 in 2003--2005 in the UV, X-ray and soft
gamma-ray bands and study the results in the context of the long-term evolution
of the source.
The 0.2-100 keV spectrum of the source is well fitted by a combination of a
soft cut-off power law and a hard power law. No improvement of the fit is
achieved if one replaces the soft cut-off power law by either a blackbody, or a
disk reflection model. During the observation period the source has reached the
historically softest state in the hard X-ray domain with a photon index
. Comparing our data with available archived X-ray data
from previous years, we find a secular evolution of the source toward softer
X-ray emission (the photon index has increased by
over the last thirty years). We argue that existing theoretical models have to
be significantly modified to account for the observed spectral evolution of the
source.Comment: 11 pages, accepted to A&
High-Energy sources before INTEGRAL -- INTEGRAL reference catalog --
We describe the INTEGRAL reference catalog which classifies previously known
bright X-ray and gamma-ray sources before the launch of INTEGRAL. These sources
are, or have been at least once, brighter than ~1 mCrab above 3 keV, and are
expected to be detected by INTEGRAL. This catalog is being used in the INTEGRAL
Quick Look Analysis to discover new sources or significantly variable sources.
We compiled several published X-ray and gamma-ray catalogs, and surveyed recent
publications for new sources. Consequently, there are 1122 sources in our
INTEGRAL reference catalog. In addition to the source positions, we show an
approximate spectral model and expected flux for each source, based on which we
derive expected INTEGRAL counting rates. Assuming the default instrument
performances and at least ~10^5 sec exposure time for any part of the sky, we
expect that INTEGRAL will detect at least ~700 sources below 10 keV and ~400
sources above 20 keV over the mission life.Comment: Accepted to A&A Letter INTEGRAL special issu
South-West extension of the hard X-ray emission from the Coma cluster
We explore the morphology of hard (18-30 keV) X-ray emission from the Coma
cluster of galaxies. We analyze a deep (1.1 Ms) observation of the Coma cluster
with the ISGRI imager on board the \emph{INTEGRAL} satellite. We show that the
source extension in the North-East to South-West (SW) direction ()
significantly exceeds the size of the point spread function of ISGRI, and that
the centroid of the image of the source in the 18-30 keV band is displaced in
the SW direction compared to the centroid in the 1-10 keV band. To test the
nature of the SW extension we fit the data assuming different models of source
morphology. The best fit is achieved with a diffuse source of elliptical shape,
although an acceptable fit can be achieved assuming an additional point source
SW of the cluster core. In the case of an elliptical source, the direction of
extension of the source coincides with the direction toward the subcluster
falling onto the Coma cluster. If the SW excess is due to the presence of a
point source with a hard spectrum, we show that there is no obvious X-ray
counterpart for this additional source, and that the closest X-ray source is
the quasar EXO 1256+281, which is located from the centroid of the
excess. The observed morphology of the hard X-ray emission clarifies the nature
of the hard X-ray "excess" emission from the Coma cluster, which is due to the
presence of an extended hard X-ray source SW of the cluster core.Comment: 7pages, 10 figure
L'effet CSI: état de l'art sur un phénomène aux multiples facettes
Depuis son lancement en 2000, la série policière "Les Experts" ("CSI : Crime Scene Investigations" en version originale) a été l'une des séries les plus populaires dans son genre tant aux Etats-Unis qu'ailleurs dans le monde. En raison de la représentation idéalisée la science forensique véhiculée au fil des épisodes, certains acteurs juridiques américains on exprimé, par l'intermédiaire de la presse populaire, l'inquiétude selon laquelle de telles séries puissent hausser les attentes des jurés vis-à-vis des indices matériels présentés au tribunal. Le terme "effet CSI" a ainsi été créé afin de désigner l'influence des séries de genre forensique, particulièrement "Les experts", sur la prise de décision des jurés lors des procès. Par la suite, l'utilisation de ce terme s'est étendue aux autres acteurs sociaux et juridiques.
Cet article a pour but de présenter en détail l' "effet CSI" par le biais d'une recherche bibliographique des travaux effectués sur le sujet. La typologie des principaux effets décrits dans la littérature, l'évolution spatio-temporelle de l'emploi de ce terme, ainsi que les principaux points de vue et constats sont présentés.
Cette compilation bibliographique révèle que les principaux champs de recherche de l' "effet CSI" peuvent changer en fonction de la zone géographique. D'une manière générale, il ressort que les séries policières peuvent être vecteurs d'informations propres à modifier la perception de la science forensique par le grand public mais qu'elles ne sont pas les seuls médias à produire une image réaliste de la criminalité et du système de justice pénale. Ces sources de divertissement peuvent quelquefois être éducatives mais peuvent également avoir pour effet de provoquer une hausse des attentes du citoyen ordinaire envers la police technique et l'indice matériel, sans pour autant constituer une menace pour le système de justice pénale
Social Support, Social and Temporal Comparisons Protect Well-Being and Health between 45 and 70 Years Old in Four Urban Communities
This study examined the impact of social support and of temporal and social comparisons on well-being and selfreported health in four capital cities: Paris, Berlin, Moscow and Beijing. Based on the lifespan control theory, an
integrative model investigating the influence of these coping strategies, especially on the psychological regulation of
health losses, was tested on 1141 respondents aged 45 to 70 years by using structural equation modelling with
multigroup comparisons. Results indicated a good fit of the model to participants' responses. In all contexts, physical
weaknesses favoured the use of social and temporal comparison strategies rather than social support. Moreover,
across the cities, coping strategies were oriented more toward protecting self-evaluation of health than toward
enhancement of well-being. Social comparison decreased the impact of physical weaknesses on health evaluation
and on well-being in the four cities, but to a lesser extent in China. Results are discussed regarding the normative
cross-cultural aspects that intervene during ageing in the four urban contexts
High resolution structural characterisation of laser-induced defect clusters inside diamond
Laser writing with ultrashort pulses provides a potential route for the
manufacture of three-dimensional wires, waveguides and defects within diamond.
We present a transmission electron microscopy (TEM) study of the intrinsic
structure of the laser modifications and reveal a complex distribution of
defects. Electron energy loss spectroscopy (EELS) indicates that the majority
of the irradiated region remains as bonded diamond.
Electrically-conductive paths are attributed to the formation of multiple
nano-scale, -bonded graphitic wires and a network of strain-relieving
micro-cracks
Simultaneous observations of the quasar 3C 273 with INTEGRAL, XMM-Newton and RXTE
INTEGRAL has observed the bright quasar 3C 273 on 3 epochs in January 2003 as
one of the first observations of the open programme. The observation on January
5 was simultaneous with RXTE and XMM-Newton observations. We present here a
first analysis of the continuum emission as observed by these 3 satellites in
the band from 3 keV to 500 keV. The continuum spectral energy distribution of
3C 273 was observed to be weak and steep in the high energies during this
campaign. We present the actual status of the cross calibrations between the
instruments on the three platforms using the calibrations available in June
2003.Comment: 4 figures, accepted for publication in A+A letter
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