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S. D. Barthelmy

Bio: S. D. Barthelmy is an academic researcher. The author has contributed to research in topics: Gamma-ray burst & Neutron star. The author has an hindex of 6, co-authored 79 publications receiving 185 citations.

Papers published on a yearly basis

Papers
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01 Oct 2006
TL;DR: The Swift/Burst Alert Telescope (BAT) provides near real-time coverage of the X-ray sky in the energy range 15-50 keV with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 s as discussed by the authors.
Abstract: The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 s. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public Web site. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity and exposure. We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries. For the new sources that are previously unpublished, we present basic data analysis and interpretations.

16 citations


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Journal ArticleDOI
15 Dec 2005-Nature
TL;DR: In this paper, the authors reported the discovery of the first radio afterglow from the short burst GRB 050724, which unambiguously associates it with an elliptical galaxy at a redshift z = 0.257.
Abstract: Despite a rich phenomenology, γ-ray bursts (GRBs) are divided1 into two classes based on their duration and spectral hardness—the long-soft and the short-hard bursts. The discovery of afterglow emission from long GRBs was a watershed event, pinpointing their origin to star-forming galaxies, and hence the death of massive stars, and indicating an energy release of about 10^(51) erg. While theoretical arguments suggest that short GRBs are produced in the coalescence of binary compact objects (neutron stars or black holes), the progenitors, energetics and environments of these events remain elusive despite recent localizations. Here we report the discovery of the first radio afterglow from the short burst GRB 050724, which unambiguously associates it with an elliptical galaxy at a redshift z = 0.257. We show that the burst is powered by the same relativistic fireball mechanism as long GRBs, with the ejecta possibly collimated in jets, but that the total energy release is 10–1,000 times smaller. More importantly, the nature of the host galaxy demonstrates that short GRBs arise from an old (> 1 Gyr) stellar population, strengthening earlier suggestions and providing support for coalescing compact object binaries as the progenitors.

410 citations

Journal ArticleDOI
15 Dec 2005-Nature
TL;DR: In this article, the authors reported the X-ray localization of a short burst (GRB 050724) with unusual gamma-ray and Xray properties, which lies off the centre of an elliptical galaxy at a redshift of z = 0.258.
Abstract: Two short (< 2 s) gamma-ray bursts (GRBs) have recently been localized and fading afterglow counterparts detected. The combination of these two results left unclear the nature of the host galaxies of the bursts, because one was a star-forming dwarf, while the other was probably an elliptical galaxy. Here we report the X-ray localization of a short burst (GRB 050724) with unusual gamma-ray and X-ray properties. The X-ray afterglow lies off the centre of an elliptical galaxy at a redshift of z = 0.258 (ref. 5), coincident with the position determined by ground-based optical and radio observations. The low level of star formation typical for elliptical galaxies makes it unlikely that the burst originated in a supernova explosion. A supernova origin was also ruled out for GRB 050709 (refs 3, 31), even though that burst took place in a galaxy with current star formation. The isotropic energy for the short bursts is 2-3 orders of magnitude lower than that for the long bursts. Our results therefore suggest that an alternative source of bursts--the coalescence of binary systems of neutron stars or a neutron star-black hole pair--are the progenitors of short bursts.

366 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented a catalog of sources detected in the first 22 months of data from the hard X-ray survey (14-195 keV) conducted with the Burst Alert Telescope (BAT) coded mask imager on the Swift satellite.
Abstract: We present the catalog of sources detected in the first 22 months of data from the hard X-ray survey (14-195 keV) conducted with the Burst Alert Telescope (BAT) coded mask imager on the Swift satellite The catalog contains 461 sources detected above the 48σ level with BAT High angular resolution X-ray data for every source from Swift-XRT or archival data have allowed associations to be made with known counterparts in other wavelength bands for over 97% of the detections, including the discovery of ~30 galaxies previously unknown as active galactic nuclei and several new Galactic sources A total of 266 of the sources are associated with Seyfert galaxies (median redshift z ~ 003) or blazars, with the majority of the remaining sources associated with X-ray binaries in our Galaxy This ongoing survey is the first uniform all-sky hard X-ray survey since HEAO-1 in 1977 Since the publication of the nine-month BAT survey we have increased the number of energy channels from four to eight and have substantially increased the number of sources with accurate average spectra The BAT 22 month catalog is the product of the most sensitive all-sky survey in the hard X-ray band, with a detection sensitivity (48σ) of 22 × 10–11 erg cm–2 s–1 (1 mCrab) over most of the sky in the 14-195 keV band

339 citations

Journal ArticleDOI
TL;DR: In this paper, the population of black holes in X-ray transients as a whole has been studied and the most updated catalogue of black hole transients is presented, together with their astrometric and dynamical properties.
Abstract: Aims. During the last ~50 years, the population of black hole candidates in X-ray binaries has increased considerably, with 59 Galactic objects being detected in transient low-mass X-ray binaries, as well as a few in persistent systems (including ~5 extragalactic binaries). Methods. We collect near-infrared, optical, and X-ray information spread over hundreds of references to study the population of black holes in X-ray transients as a whole.Results. We present the most updated catalogue of black hole transients. This contains X-ray, optical, and near-infrared observations, together with their astrometric and dynamical properties. The catalogue provides new and useful information in both statistical and observational parameters and provides a thorough and complete overview of the black hole population in the Milky Way. Analysing the distances and spatial distribution of the observed systems, we estimate a total population of ~1300 Galactic black hole transients. This means that we have only discovered less than ~5% of the total Galactic distribution.

303 citations

Journal ArticleDOI
09 Mar 2006-Nature
TL;DR: In this paper, the authors present detailed observations of the γ-ray, X-ray and near-infrared and optical spectra of the afterglow of GRB 050904.
Abstract: The γ-ray burst GRB 050904, detected by the Swift satellite on 4 September last year, is one of the most distant objects ever observed. Its redshift of z = 6.3 equates to an explosion taking place 12.8 billion years ago, when the Universe was a mere 890 million years old. Three groups this week present detailed observations of the γ-ray, X-ray, near-infrared and optical spectra of the afterglow of GRB 050904. The results begin to paint a picture of the conditions prevailing when the parent body exploded and suggest that the γ-ray bursts that we see in the future can be used by cosmologists to probe the early Universe for evidence of star and galaxy formation, nucleosynthesis and reionization. The prompt γ-ray emission from γ-ray bursts (GRBs) should be detectable out to distances of z > 10 (ref. 1), and should therefore provide an excellent probe of the evolution of cosmic star formation, reionization of the intergalactic medium, and the metal enrichment history of the Universe1,2,3,4. Hitherto, the highest measured redshift for a GRB has been z = 4.50 (ref. 5). Here we report the optical spectrum of the afterglow of GRB 050904 obtained 3.4 days after the burst; the spectrum shows a clear continuum at the long-wavelength end of the spectrum with a sharp cut-off at around 9,000 A due to Lyman α absorption at z ≈ 6.3 (with a damping wing). A system of absorption lines of heavy elements at z = 6.295 ± 0.002 was also detected, yielding the precise measurement of the redshift. The Si ii fine-structure lines suggest a dense, metal-enriched environment around the progenitor of the GRB.

303 citations