scholarly journals RAPID OPTICAL FOLLOW-UP OBSERVATIONS OF GAMMA-RAY BURSTS

2012 ◽  
Vol 12 ◽  
pp. 48-57
Author(s):  
MICHEL BOËR
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Optical Observations ◽  
Gamma Ray Burst ◽  
Infrared Wavelengths ◽  
New Instruments ◽  
Prompt Emission

The prompt emission of gamma-ray burst sources is still the main means of detection, and a privilegied access to the souce dynamics. It is detected from radio to GeV energies, and its study is crucial for the overall understanding of the phenomenom. We present here a panorama of the rapid optical observations, and what can be infered from the data. We will discuss also the new instruments which are planned for the observation of the prompt and early afterglow at optical and infrared wavelengths, with spectral capabilities.

scholarly journals DESAlert: Enabling Real-Time Transient Follow-Up with Dark Energy Survey Data

2016 ◽  
Vol 33 ◽  
Author(s):  
A. Poci ◽  
K. Kuehn ◽  
T. Abbott ◽  
F. B. Abdalla ◽  
S. Allam ◽  
...  
Keyword(s):  
Dark Energy ◽  
Real Time ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Host Galaxies ◽  
Gamma Ray Burst ◽  
Dark Energy Survey ◽  
Data Products ◽  
Energy Survey

AbstractThe Dark Energy Survey is undertaking an observational programme imaging 1/4 of the southern hemisphere sky with unprecedented photometric accuracy. In the process of observing millions of faint stars and galaxies to constrain the parameters of the dark energy equation of state, the Dark Energy Survey will obtain pre-discovery images of the regions surrounding an estimated 100 gamma-ray bursts over 5 yr. Once gamma-ray bursts are detected by, e.g., the Swift satellite, the DES data will be extremely useful for follow-up observations by the transient astronomy community. We describe a recently-commissioned suite of software that listens continuously for automated notices of gamma-ray burst activity, collates information from archival DES data, and disseminates relevant data products back to the community in near-real-time. Of particular importance are the opportunities that non-public DES data provide for relative photometry of the optical counterparts of gamma-ray bursts, as well as for identifying key characteristics (e.g., photometric redshifts) of potential gamma-ray burst host galaxies. We provide the functional details of the DESAlert software, and its data products, and we show sample results from the application of DESAlert to numerous previously detected gamma-ray bursts, including the possible identification of several heretofore unknown gamma-ray burst hosts.

scholarly journals GAMMA-RAY BURSTS: PROGRESS, PROBLEMS & PROSPECTS

2004 ◽  
Vol 19 (15) ◽  
pp. 2385-2472 ◽  
Author(s):  
BING ZHANG ◽  
PETER MÉSZÁROS
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Current Understanding ◽  
Shock Model ◽  
Gamma Ray Burst ◽  
Prompt Emission

The cosmological gamma-ray burst (GRB) phenomenon is reviewed. The broad observational facts and empirical phenomenological relations of the GRB prompt emission and afterglow are outlined. A well-tested, successful fireball shock model is introduced in a pedagogical manner. Several important uncertainties in the current understanding of the phenomenon are reviewed, and prospects of how future experiments and extensive observational and theoretical efforts may address these problems are discussed.

scholarly journals Gamma-Ray Burst Prompt Correlations

2018 ◽  
Vol 2018 ◽  
pp. 1-31 ◽  
Author(s):  
M. G. Dainotti ◽  
R. Del Vecchio ◽  
M. Tarnopolski
Keyword(s):  
Gamma Ray ◽  
Theoretical Models ◽  
Gamma Ray Bursts ◽  
Gamma Ray Burst ◽  
The Past ◽  
Two Parameter ◽  
Prompt Emission

The mechanism responsible for the prompt emission of gamma-ray bursts (GRBs) is still a debated issue. The prompt phase-related GRB correlations can allow discriminating among the most plausible theoretical models explaining this emission. We present an overview of the observational two-parameter correlations, their physical interpretations, and their use as redshift estimators and possibly as cosmological tools. The nowadays challenge is to make GRBs, the farthest stellar-scaled objects observed (up to redshift z=9.4), standard candles through well established and robust correlations. However, GRBs spanning several orders of magnitude in their energetics are far from being standard candles. We describe the advances in the prompt correlation research in the past decades, with particular focus paid to the discoveries in the last 20 years.

scholarly journals A complete sample of long bright Swift gamma ray bursts

2013 ◽  
Vol 371 (1992) ◽  
pp. 20120235 ◽  
Author(s):  
Gianpiero Tagliaferri ◽  
Ruben Salvaterra ◽  
Sergio Campana ◽  
Stefano Covino ◽  
Paolo D’Avanzo ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Gamma Ray ◽  
Cosmic Time ◽  
Gamma Ray Bursts ◽  
Spectral Energy ◽  
Complete Sample ◽  
Peak Flux ◽  
S Peak ◽  
Prompt Emission

Complete samples are the basis of any population study. To this end, we selected a complete subsample of Swift long bright gamma ray bursts (GRBs). The sample, made up of 58 bursts, was selected by considering bursts with favourable observing conditions for ground-based follow-up observations and with the 15–150 keV 1 s peak flux above a flux threshold of 2.6 photons cm −2  s −1 . This sample has a redshift completeness level higher than 90 per cent. Using this complete sample, we investigate the properties of long GRBs and their evolution with cosmic time, focusing in particular on the GRB luminosity function, the prompt emission spectral-energy correlations and the nature of dark bursts.

STOCHASTIC WAKEFIELD PLASMA ACCELERATION IN GAMMA-RAY BURSTS

2007 ◽  
Vol 21 (03n04) ◽  
pp. 627-632
Author(s):  
G. BARBIELLINI ◽  
F. LONGO ◽  
N. OMODEI ◽  
D. GIULIETTI ◽  
A. CELOTTI ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Plasma Acceleration ◽  
Gamma Ray Burst ◽  
Initial Burst ◽  
X Ray ◽  
Wake Field ◽  
Prompt Emission

Gamma-Ray Burst (GRB) prompt emission can, for specific conditions, be so powerful and short-pulsed to strongly influence any surrounding plasma. In this paper, we briefly discuss the possibility that a very intense initial burst of radiation produced by GRBs satisfy the intensity and temporal conditions to cause stochastic wake-field particle acceleration in a surrounding plasma of moderate density. We consider a simple but realistic GRB model for which particle wake-field acceleration can first be excited by a very strong low-energy precursor, and then be effective in producing the observed prompt X-ray and gamma-ray GRB emission.

scholarly journals Study of very early phase GRB afterglows with MITSuME

2011 ◽  
Vol 7 (S279) ◽  
pp. 387-388
Author(s):  
Yoshihiko Saito ◽  
Yoichi Yatsu ◽  
Hideya Nakajima ◽  
Nobuyuki Kawai ◽  
Katsuaki Asano ◽  
...  
Keyword(s):  
Real Time ◽  
Early Phase ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Optical Observations ◽  
The Internet ◽  
Photometric Observations ◽  
Optical Telescopes

AbstractWe review the results of very early phase optical follow-up observations of recent gamma-ray bursts (GRBs) with the multi-color optical telescopes “MITSuME”. The MITSuME telescopes were designed to perform “real time” and “automatic” follow-up observations prompted by the GCN alerts via the Internet. The rapidly slewing equatorial mounts allow MITSuME to start photometric observations within 100 seconds after the trigger for several GRBs. In particular, we detected a brightening just after the trigger for two GRBs. These phenomena could be interpreted as the “on-set” of afterglow. In this paper we summarize these optical observations with a brief interpretation.

scholarly journals Prompt optical emission as a signature of synchrotron radiation in gamma-ray bursts

2019 ◽  
Vol 628 ◽  
pp. A59 ◽  
Author(s):  
G. Oganesyan ◽  
L. Nava ◽  
G. Ghirlanda ◽  
A. Melandri ◽  
A. Celotti
Keyword(s):  
Synchrotron Radiation ◽  
Parameter Space ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Spectral Shape ◽  
Low Energy ◽  
Optical Observations ◽  
X Rays ◽  
Thermal Component ◽  
Prompt Emission

Information on the spectral shape of prompt emission in gamma-ray bursts (GRB) is mostly available only at energies ≳10 keV, where the main instruments for GRB detection are sensitive. The origin of this emission is still very uncertain because of the apparent inconsistency with synchrotron radiation, which is the most obvious candidate, and the resulting need for considering less straightforward scenarios. The inclusion of data down to soft X-rays (∼0.5 keV), which are available only in a small fraction of GRBs, has firmly established the common presence of a spectral break in the low-energy part of prompt spectra, and even more importantly, the consistency of the overall spectral shape with synchrotron radiation in the moderately fast-cooling regime, the low-energy break being identified with the cooling frequency. In this work we further extend the range of investigation down to the optical band. In particular, we test the synchrotron interpretation by directly fitting a theoretically derived synchrotron spectrum and making use of optical to gamma-ray data. Secondly, we test an alternative model that considers the presence of a black-body component at ∼keV energies, in addition to a non-thermal component that is responsible for the emission at the spectral peak (100 keV–1 MeV). We find that synchrotron radiation provides a good description of the broadband data, while models composed of a thermal and a non-thermal component require the introduction of a low-energy break in the non-thermal component in order to be consistent with optical observations. Motivated by the good quality of the synchrotron fits, we explore the physical parameter space of the emitting region. In a basic prompt emission scenario we find quite contrived solutions for the magnetic field strength (5 G < B′< 40 G) and for the location of the region where the radiation is produced (Rγ >  1016 cm). We discuss which assumptions of the basic model would need to be relaxed in order to achieve a more natural parameter space.

scholarly journals Gamma-ray bursts: not so much deadlier than we thought

2020 ◽  
Vol 500 (2) ◽  
pp. 1970-1973
Author(s):  
Brian C Thomas ◽  
Dimitra Atri ◽  
Adrian L Melott
Keyword(s):  
Gamma Ray ◽  
Planetary Atmospheres ◽  
Muon Flux ◽  
Gamma Ray Bursts ◽  
Gamma Ray Burst ◽  
Planet Surface ◽  
Prompt Emission

ABSTRACT We analyse the additional effect on planetary atmospheres of recently detected gamma-ray burst afterglow photons in the range up to 1 TeV. For an Earth-like atmosphere, we find that there is a small additional depletion in ozone versus that modeled for only prompt emission. We also find a small enhancement of muon flux at the planet surface. Overall, we conclude that the additional afterglow emission, even with TeV photons, does not result in a significantly larger impact over that found in past studies.

scholarly journals RIBOTS: An Automatic Telescope System for Gamma-Ray Burst Follow-Up Observations

2001 ◽  
Vol 183 ◽  
pp. 155-156
Author(s):  
Yuji Urata ◽  
Nobuyuki Kawai ◽  
Atsumasa Yoshida ◽  
Mitsuhiro Kohama ◽  
Tetsuya Kawabata ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Observation System ◽  
Alert System ◽  
Gamma Ray Burst ◽  
Fully Automatic ◽  
Optical Flashes ◽  
Optical Transient ◽  
Telescope System

AbstractWe are constructing a fully automatic observation system named RIBOTS (RIken-Bisei Optical Transient Seeker). We aim to detect optical flashes and early afterglows of Gamma-ray bursts (GRB) with RIBOTS. We are constructing RIBOTS with a small telescope because a quick pointing to the burst is essential for our purpose. RIBOTS is linked to the GRB alert system provided by the HETE-2 satellite.

SWIFT OBSERVATIONS OF GAMMA-RAY BURSTS

2008 ◽  
Vol 17 (09) ◽  
pp. 1311-1317
Author(s):  
NEIL GEHRELS
Keyword(s):  
Gamma Ray ◽  
High Redshift ◽  
Gamma Ray Bursts ◽  
Optical Observations ◽  
Nearby Galaxy ◽  
X Ray ◽  
Star Forming ◽  
Star Forming Regions ◽  
Other Information

The Swift mission, launched on 20 November 2004, is detecting ~ 100 gamma-ray bursts (GRBs) each year, and immediately (within ~ 90 s) starting X-ray and UV/optical observations of the afterglow. It has already collected an impressive database including prompt emission to higher sensitivities than BATSE, uniform monitoring of afterglows, and rapid follow-up by other observatories notified through the Gamma-ray bursts Coordinates Network (GCN). The X-ray afterglows have been found to have complex temporal shapes including tails emission from the prompt phase and bright flares. X-ray and optical afterglow detections from short bursts have led to accurate localizations. It is found that they can occur in non-star forming galaxies or regions, whereas long GRBs are strongly concentrated within star forming regions. This is consistent with the NS merger model. Swift has greatly increased the redshift range of GRB detection. The highest redshift GRBs, at z ~ 5-6, are approaching the era of reionization. Ground-based deep optical spectroscopy of high redshift bursts is giving metallicity measurements and other information on the source environment to much greater distance than other techniques. The localization of GRB 060218 in a nearby galaxy, and association with SN 2006aj, added a valuable member to the class of GRBs with detected supernova. The prospects for future progress are excellent given the > 10 year orbital lifetime of the Swift satellite.

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