Search For Bursts Research Articles

Determining the Gamma-Ray Burst Distance Scale: Observational Prospects

The BATSE instrument on the Compton Gamma-Ray Observatory has demonstrated that we live near the center of an isotropic but bounded distribution of gamma-ray burst sources but has left unsettled whether the bursts occur in our own Galaxy or at cosmological distances. Because a distance and energy scale is crucial to constraining burst models, this distance ambiguity must be resolved. The key experiment that would distinguish the possibilities is a search for bursts from the halo of M31 or other nearby galaxies. We discuss the observational prospects for this test, showing that no telescope now in orbit or scheduled for launch can settle the debate, but that an experiment could be done with a low-cost, dedicated instrument.

The LVD experiment at Gran Sasso

The Large-Volume Detector (LVD) in the Gran Sasso underground Laboratory is a multipurpose detector consisting of a large volume of liquid scintillator (at present 562 tons are in data taking) interleaved with limited-streamer tubes. Several physical problems are investigated with LVD, the major being the search for neutrino bursts from gravitational stellar collapses in our Galaxy. In this paper we discuss some results on cosmic neutrinos and cosmic-ray muons obtained with the first of the five towers of LVD (operational since June 1992) and part of the second tower (operational since June 1994). The results of the search for supernovae neutrinos show that LVD is a neutrino observatory able to detect neutrinos of different flavours from gravitational stellar collapses in all our Galaxy, over a wide range of burst durations. Indeed, the carbon-based liquid-scintillator target gives a unique possibility to directly detect neutral- and charged-currents neutrino interactions with a very good signature. This characteristic of LVD allows us to make an indirect estimate of the neutrino rest mass and of neutrino oscillations from supernovae in our Galaxy. No evidence for burst candidates has been found in the data recorded from June 1992 to March 1995, for a total live time of 682 days and a total exposure of 613 tons per year. We present the results of a time coincidence analysis between low-energy signals, eventually due to neutrinos of different flavours, and γ-ray bursts (GRBs) detected by the BATSE experiment. This search covers the period from June 1993 to March 1995, during which 41 GRBs have been selected from the BATSE data. Since no excess of events in LVD has been found, upper limits on the neutrino fluxes are reported for (νe, p), and for neutral- and charged-currents neutrino interactions of different flavours with the C-nuclei of the scintillator. The muon intensity as a function of slant depth is presented. These measurements, obtained during a live time period of 11.556 hours, cover a slant depths range from about 3000 to about 20 000 hg/cm2 of standard rock and extend over five decades of intensity. An interesting result is that the muon flux is independent of slant depth beyond a depth of about 14 000 hg/cm2 of standard rock, and corresponds to near horizontal muons. This is direct evidence that this flux is due to atmospheric neutrinos interacting in the rock surrounding LVD.

Search for Gamma Ray Bursts of energy Eγ ≥10 GeV and Eγ ≥ 100 TeV in correlation with BATSE events

We present the results of a search for Gamma Ray Bursts at energies Eγ ≥ 10 GeV and Eγ ≥ 100 TeV made by the EAS-TOP Air Shower Array in correlation with ∼ 50 events detected by BATSE in the last 3 years.

Review of GRANAT observations of gamma-ray bursts

The GRANAT observatory was launched into a high apogee orbit on 1 December, 1989. Three instruments onboard GRANAT - PHEBUS, WATCH and SIGMA are able to detect gamma-ray bursts in a very broad energy range from 6 keV up to 100 MeV. Over 250 gamma-ray bursts were detected. We discuss the results of the observations of the time histories and spectral evolution of the detected events provided by the different instruments in different energy ranges. Short Gamma-Ray Bursts ( 2 s) events. Evidence of the existence of four differently behaving componenents in gamma-ray burst spectra is discussed. Statistical properties of the gamma-ray burst sources based on the 5 years of observations with (∼ 10−6 erg/cm2) sensitivity as well as the results of high sensitivity (∼ 10−8 erg/cm2) search for Gamma-Ray Bursts within the SIGMA telescope field of view are reviewed.

The search for GRB from primordial black hole evaporation

The search for high energyγ ray bursts (GRBs) from primordial black holes (PBHs) has continued for the past 20 years. We discuss a very interesting group of GRBs of very short time duration and an increasing hard spectrum from the published BATSE catalog. We point out that the trend, i.e. anti-correlation of hardness ratio vs. GRB duration, would be expected if some of the short GRBs came from black holes evaporation. We discuss the possibility that the onset of the quark-gluon plasma can give rise to such GRB from PBH evaporation.

New astronomies with Extensive Air Showers

We discuss some recent results obtained in the fields of VHE-UHE gamma-ray astronomy, search for gamma-ray bursts at high energies, and UHE neutrino astronomy by means of Extensive Air Showers (EAS) arrays. The technical achievements and future possibilities are outlined.

Search for Cosmic Ray Bursts with Energy Above 1014 eV

The Beijing Huairou extensive air shower (EAS) array has been operating since March 1988. Using data observed during the period from April 1991 through January 1993, a burst of 12 EAS events were observed within 2-minute interval beginning at 4:41'54" ante meridiem on December 30 1991 universal time, while only 2 EAS events on average would have been expected during such time interval.

Search of the energetic gamma-ray experiment telescope (EGRET) data for high-energy gamma-ray microsecond bursts

view Abstract Citations (38) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Search of the Energetic Gamma-Ray Experiment Telescope (EGRET) Data for High-Energy Gamma-Ray Microsecond Bursts Fichtel, C. E. ; Bertsch, D. L. ; Dingus, B. L. ; Esposito, J. A. ; Hartman, R. C. ; Hunter, S. D. ; Kanbach, G. ; Kniffen, D. A. ; Lin, Y. C. ; Mattox, J. R. ; Mayer-Hasselwander, H. A. ; McDonald, L. ; Michelson, P. F. ; von Montigny, C. ; Nolan, P. L. ; Schneid, E. J. ; Sreekumar, P. ; Thompson, D. J. Abstract Hawking (1974) and Page & Hawking (1976) investigated theoretically the possibility of detecting high-energy gamma rays produced by the quantum-mechanical decay of a small black hole created in the early universe. They concluded that, at the very end of the life of the small black hole, it would radiate a burst of gamma rays peaked near 250 MeV with a total energy of about 1034 ergs in the order of a microsecond or less. The characteristics of a black hole are determined by laws of physics beyond the range of current particle accelerators; hence, the search for these short bursts of high-energy gamma rays provides at least the possibility of being the first test of this region of physics. The Compton Observatory Energetic Gamma-Ray Experiment Telescope (EGRET) has the capability of detecting directly the gamma rays from such bursts at a much fainter level than SAS 2, and a search of the EGRET data has led to an upper limit of 5 x 10-2 black hole decays per cu pc per yr, placing constraints on this and other theories predicting microsecond high-energy gamma-ray bursts. Publication: The Astrophysical Journal Pub Date: October 1994 DOI: 10.1086/174758 Bibcode: 1994ApJ...434..557F Keywords: Black Holes (Astronomy); Decay; Gamma Ray Astronomy; Gamma Ray Bursts; Quantum Mechanics; Gamma Ray Observatory; Gamma Ray Telescopes; Sas-2; Statistical Analysis; Astronomy; BLACK HOLE PHYSICS; GAMMA RAYS: BURSTS full text sources ADS |

Coincidence experiments between interferometric and resonant bar detectors of gravitational waves

Gravitational wave coincidence experiments between bars and interferometers may be an attractive option once the new generation of full scale interferometers begins taking data. We discuss various ways in which these disparate types of data can be compared in searches for bursts (from supernovae, for example), for pulsar signals, and for a stochastic background. Comparison of broadband interferometer data with narrowband bar data is appropriate in most searches for bursts, but in many cases the results---especially null results (upper limits)---are difficult to interpret. By narrowbanding the interferometer data to the bandwidth of the bar detector, one produces data sets that may give much clearer information in certain burst searches and that are appropriate for searches for a stochastic background of gravitational waves. We suggest, in fact, that there are circumstances where searches for a stochastic background could be more efficiently performed between a bar and an interferometer than between two interferometers. We examine, in some detail, the effect of narrowbanding the interferometer data. We apply this method to a real interferometer and bar data and assess its signal-to-noise performance for different classes of gravitational wave signals.

Search for a high-energy γ-ray burst by an airborne experiment

A search for high-energy γ-ray bursts was carried out by an airborne experiment. We loaded a lead-glass-based electron-telescope onto a cargo airplane and measured secondary electrons at airplane altitude. The energy threshold of this method was 20 GeV for primary γ-rays; the angular resolution was 1.5 degrees. We searched for transient events from the same directions within various time windows. The total exposure time was 54.6 hours, and we set upper limits for the full-sky rates of high-energy γ-ray bursts.

A high-sensitivity search for gamma-ray bursts by the SIGMA telescope on board GRANAT (the Galactic center and all sky data)

During more than 2 years of the GRANAT mission the gamma-ray burst (GRB) cell of the narrow aperture coded mask telescope SIGMA was operating for ∼5300 hr. The coding system of SIGMA is capable to localize with arcmin accuracy the GRB events detected through the 18:1 by 16:8 coded vield of view. The sensitivity of the cell to the on-axis events is very high, ∼3×10 −8 and 8×10 −8 ergs cm −2 in the 40-90 keV band for 0.25 and 2.0 s of integration time. Nevertheless, no bursts were actually found within the coded field of view

Search for neutrino bursts from collapsing stars with the MACRO detector

Search for neutrino bursts from collapsing stars with the MACRO detector

Search for cosmic γ-ray bursts in the (1÷50) GeV energy range

A search for cosmic gamma-ray bursts in the GeV energy range has been performed by means of the EAS-TOP Extensive Air Shower array at Campo Imperatore (Gran Sasso Laboratories) during the period March–December 1990. In 2566.5 hours of measurement the obtained upper limit to the rate of bursts of amplitude >2% of the cosmic-ray intensity and time duration τ=1 s, isR≤7.9y−1 (90% c.l.). Assuming for γ-rays a differential energy spectrumS(E0)≈E0−2.5, the corresponding upper limit to the energy flux of γ-rays with energy >5 GeV in bursts of duration τ≤1 s is Φ<8.3·10−5erg cm−2.

Gamma-ray burster counterparts - Archival data

This paper reports on the results of a search for optical transient images associated with gamma-ray bursters based on the collection of archival photographs at the Harvard College Observatory. This study searched through over 32,000 plates showing 16 gamma-ray burst error regions. The primary result is the identification of three optical transient images. The recurrence time scale for optical events with a gamma-ray to optical fluence ratio of less than 1000 is estimated to be 1.3 yr (with a 99-percent confidence interval of between 0.41 and 4.8 yr). A control study was simultaneously made where regions of the sky with no bursters were examined. The control region was 15.6 times larger than the burst search region, yet no optical transients were found. This paper describes in detail the methodology and the statistical results. Close attention is paid to a detailed analysis of the three optical transient images.

High modularity fast charge-time digitizer in neutrino burst detection

A 1 MHz high modularity electronic system for large-volume detectors in the search for neutrino bursts from stellar collapses has been developed. Technical details and final results of tests performed on the prototypes are presented.

The UTD/UCLA high resolution gamma ray telescope

Abstract The UTD/UCLA collaboration is developing and testing a high resolution large area gamma ray telescope to be employed in space for studying diffuse and point like sources of cosmic gamma rays in the 1 MeV to 20 GeV energy range. The major objectives of this program are (1) the Study of new point like sources of MeV and GeV gamma rays, (2) observation of characteristic angular variations in the diffuse gamma rays to identify their primary origin, (3) search for gammas from the decay and annihilation of cold dark matter particles, (4′ search for bursts from exotic objects, and (5) search for a massive black hole in the center of our galaxy.

Search for Bursts of Ultra-High-Energy Photons from Astrophysical Sources

AbstractThe Buckland Park air shower array has been used for some time as an ultra-high-energy gamma-ray telescope operating at photon energies of about 1015 eV. Other such telescopes have reported apparent bursts of events from astrophysical objects under study. We report here searches for UHE bursts from 14 southern hemisphere objects studied in our UHE programme. No conclusive evidence has been found for any UHE burst activity from these sources in the period 1986-1988. There is possible evidence for activity associated with 1700-377 and SN1987A.

Ultrahigh-energy pulsed emission from Hercules X-1 with anomalous air-shower muon production.

A search for bursts of air-shower events from Hercules X-1 at energies above 50 TeV during the calendar period 2 April 1986 to 5 July 1987 yielded two significant bursts, both occurring on UT 24 July 1986. The events during these bursts were pulsed with a period of 1.235 68 s, significantly different from estimates of the contemporaneous x-ray period. The probability that this represents random statistical fluctuations of the background is estimated to be 2 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}5}$. The muon content of the burst events is anomalous when compared with expectations from $\ensuremath{\gamma}$-ray showers.

Searches for low-frequency bursts of gravitational radiation

Searches for low-frequency bursts of gravitational radiation

The frequency of weak gamma-ray bursts

A search for weak gamma-ray bursts was conducted using a sensitive balloon-borne detector. One burst was detected in 64 hr of observation. The upper limit to the burst rate is 2300 bursts/yr above 6 x 10 to the -7th ergs/sq cm for simple spatial distribution models. Comparison with satellite results indicates that the slope of the log N-log S curve can be no steeper than -1 between 10 to the -4th and 10 to the -6th ergs/sq cm. A detailed procedure for calculating detector sensitivity to bursts is provided. 18 references.