308 research outputs found
No Evidence for Gamma-Ray Burst/Abell Cluster or Gamma- Ray Burst/Radio-Quiet Quasar Correlations
We examine the recent claims that cosmic gamma-ray bursts are associated with
either radio-quiet quasars or Abell clusters. These associations were based on
positional coincidences between cataloged quasars or Abell clusters, and
selected events from the BATSE 3B catalog of gamma-ray bursts. We use a larger
sample of gamma-ray bursts with more accurate positions, obtained by the 3rd
Interplanetary Network, to re-evaluate these possible associations. We find no
evidence for either.Comment: Accepted for publication in the Astrophysical Journa
A second catalog of gamma ray bursts: 1978 - 1980 localizations from the interplanetary network
Eighty-two gamma ray bursts were detected between 1978 September 14 and 1980 February 13 by the experiments of the interplanetary network (Prognoz 7, Venera 11 and 12 SIGNE experiments, Pioneer Venus Orbiter, International Sun-Earth Explorer 3, Helios 2, and Vela). Sixty-five of these events have been localized to annuli or error boxes by the method of arrival time analysis. The distribution of sources is consistent with isotropy, and there is no statistically convincing evidence for the detection of more than one burst from any source position. The localizations are compared with those of two previous catalogs
Three precise gamma-ray burst source locations
The precise source regions of three moderately intense gamma ray bursts are derived. These events were observed with the first interplanetary burst sensor network. The optimum locations of the detectors, widely separated throughout the inner solar system, allowed for high accuracy, over-determined source fields of size 0.7 to 7.0 arc-min(2). All three locations are at fairly high galactic latitude in regions of low source confusion; none can be identified with a steady source object. Archived photographs were searched for optical transients that are able to be associated with these source fields; one such association was made
Detection of a fast, intense and unusual gamma ray transient
An unusual transient pulse of approximately 50 keV was detected by the gamma-ray burst sensor network using nine space probes and satellites. Its characteristics are unlike those of the known variety of gamma-ray bursts and therefore suggest that it was formed either by a completely different origin species or in a very different manner. It is identified with the LMC supernova remnant N49
Limits to the burster repetition rate as deduced from the 2nd catalog of the interplanetary network
The burster repetition rate is an important parameter in many gamma ray burst models. The localizations of the interplanetary network, which have a relatively small combined surface area, may be used to estimate the average repetition rate. The method consists of (1) estimating the number of random overlaps between error boxes expected in the catalog and comparing this number to that actually observed; (2) modeling the response of the detectors in the network, so that the probability of detecting a burst can be estimated; and (3) simulating the arrival of bursts at the network assuming that burster repetition is governed by a Poisson process. The application of this method for many different burster luminosity functions shows that (1) the lower limit to the burster repetition rate depends strongly upon the assumed luminosity function; (2) the best lower limit to the repetition period obtainable from the data of the network is about 100 months; and (3) that a luminosity function for all bursters similar to that of the 1979 Mar 5 burster is inconsistent with the data
Are Abell Clusters Correlated with Gamma-Ray Bursts?
A recent study has presented marginal statistical evidence that gamma-ray
burst sources are correlated with Abell clusters, based on analyses of bursts
in the BATSE 3B catalog. Using precise localization information from the 3rd
Interplanetary Network, we have reanalyzed this possible correlation. We find
that most of the Abell clusters which are in the relatively large 3B error
circles are not in the much smaller IPN/BATSE error regions. We believe that
this argues strongly against an Abell cluster-gamma-ray burst correlation.Comment: accepted for publication in Astrophysical Journal Letter
Lognormal Properties of SGR 1806-20 and Implications for Other SGR Sources
The time interval between successive bursts from SGR 1806-20 and the
intensity of these bursts are both consistent with lognormal distributions.
Monte Carlo simulations of lognormal burst models with a range of distribution
parameters have been investigated. The main conclusions are that while most
sources like SGR 1806-20 should be detected in a time interval of 25 years,
sources with means about 100 times longer have a probability of about 5\% of
being detected in the same interval. A new breed of experiments that operate
for long periods are required to search for sources with mean recurrence
intervals much longer than SGR 1806-20.Comment: 4 pages, latex with seperate file containing 2 uuencoded, gzip'ed,
tarred, .eps figures. Replaced with file that does not use kluwer.sty to
allow automatic postscript generation. To appear in proceedings of ESLAB 2
The Interplanetary Network Supplement to the BeppoSAX Gamma-Ray Burst Catalogs
Between 1996 July and 2002 April, one or more spacecraft of the
interplanetary network detected 787 cosmic gamma-ray bursts that were also
detected by the Gamma-Ray Burst Monitor and/or Wide-Field X-Ray Camera
experiments aboard the BeppoSAX spacecraft. During this period, the network
consisted of up to six spacecraft, and using triangulation, the localizations
of 475 bursts were obtained. We present the localization data for these events.Comment: 89 pages, 3 figures. Submitted to the Astrophysical Journal
Supplement Serie
Determining the quality and complexity of next-generation sequencing data without a reference genome
Genomics, epigenetics, population genetics and bioinformatic
Magnetar outbursts: an observational review
Transient outbursts from magnetars have shown to be a key property of their
emission, and one of the main way to discover new sources of this class. From
the discovery of the first transient event around 2003, we now count about a
dozen of outbursts, which increased the number of these strongly magnetic
neutron stars by a third in six years. Magnetar outbursts might involve their
multi-band emission resulting in an increased activity from radio to hard
X-ray, usually with a soft X-ray flux increasing by a factor of 10-1000 with
respect to the quiescent level. A connected X-ray spectral evolution is also
often observed, with a spectral softening during the outburst decay. The flux
decay times vary a lot from source to source, ranging from a few weeks to
several years, as also the decay law which can be exponential-like, a power-law
or even multiple power-laws can be required to model the flux decrease. We
review here on the latest observational results on the multi-band emission of
magnetars, and summarize one by one all the transient events which could be
studied to date from these sources.Comment: 34 pages, 6 figures. Chapter of the Springer Book ASSP 7395
"High-energy emission from pulsars and their systems", proceeding of the Sant
Cugat Forum on Astrophysics (12-16 April 2010). Review updated to January
201
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