BATSE Observations of Gamma‐Ray Burst Spectra. III. Low‐Energy Behavior of Time‐averaged Spectra

Preece, R.; Briggs, M. S.; Pendleton, G. N.; Pačiesas, W. S.; Matteson, J. L.; Band, D. L.; Skelton, R. T.; Meegan, C.

doi:10.1086/178146

Cited by 59 publications

(71 citation statements)

References 10 publications

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“…These results are consistent with the identification of the line-of-death of GRB spectra 45 which shows that about one third of all measured low-energy spectralindices (α) are inconsistent with slow-cooling synchrotron emission and nearly all exclude the possibility of fast-cooling synchrotron emission 14 . Hence, both the observed α distribution and the very narrow shapes of the observed spectra put heavy constraints on the applicable synchrotron models to GRBs.…”

Section: 38supporting

confidence: 89%

Appearances of the jet photosphere in GRB spectra

Acuner¹,

Ryde²

2017

The Fourteenth Marcel Grossmann Meeting

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There are several strong arguments for considering photospheric emission in GRBs. Here, we describe the two main appearances of the photospheric emission that are currently discussed. In the multi-component models the photosphere only contributes to a part of the spectrum, while the main part is due to optically-thin synchrotron emission. In the photospheric emission models the whole emission spectrum is from the photosphere: The emission spectrum has been altered due to subphotospheric dissipation and/or off-axis emission. In many cases, though, it is difficult to distinguish between these models on a purely statistical ground. Therefore, more detailed predictions from different physical scenarios should be tested on the observations.

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Section: 38supporting

confidence: 89%

Appearances of the jet photosphere in GRB spectra

Acuner¹,

Ryde²

2017

The Fourteenth Marcel Grossmann Meeting

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“…1 showing that in the crucial energy range of interest Notes. (*) This energy range varied depending on the gain of the detectors where the lower end of the range could be as low as 5 keV for a high gain setting (Preece et al 1996). References.…”

Section: Fermi Gbm and Batse/cgro Comparisonmentioning

confidence: 99%

“…(1) Preece et al (1996), (2) Meegan et al (2009). (below ∼30 keV), the NaIs have a greater effective area than the SD detectors. Additionally, while Preece et al (1996) only used a single SD detector, multiple NaI detectors were used in our analysis in all but 3 GRBs (see Sect.…”

Section: Fermi Gbm and Batse/cgro Comparisonmentioning

confidence: 99%

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Anomalies in low-energy gamma-ray burst spectra with theFermiGamma-ray Burst Monitor

Tierney

McBreen

Preece

et al. 2013

A&A

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Context. A Band function has become the standard spectral function used to describe the prompt emission spectra of gamma-ray bursts (GRBs). However, deviations from this function have previously been observed in GRBs detected by BATSE and in individual GRBs from the Fermi era. Aims. We present a systematic and rigorous search for spectral deviations from a Band function at low energies in a sample of the first two years of high fluence, long bursts detected by the Fermi Gamma-ray Burst Monitor (GBM). The sample contains 45 bursts with a fluence greater than 2 × 10 −5 erg/cm 2 (10−1000 keV).Methods. An extrapolated fit method is used to search for low-energy spectral anomalies, whereby a Band function is fit above a variable low-energy threshold and then the best fit function is extrapolated to lower energy data. Deviations are quantified by examining residuals derived from the extrapolated function and the data and their significance is determined via comprehensive simulations which account for the instrument response. This method was employed for both time-integrated burst spectra and time-resolved bins defined by a signal-to-noise ratio of 25σ and 50σ. Results. Significant deviations are evident in 3 bursts (GRB 081215A, GRB 090424 and GRB 090902B) in the time-integrated sample (∼7%) and 5 bursts (GRB 090323, GRB 090424, GRB 090820, GRB 090902B and GRB 090926A) in the time-resolved sample (∼11%). Conclusions. The advantage of the systematic, blind search analysis is that it can demonstrate the requirement for an additional spectral component without any prior knowledge of the nature of that extra component. Deviations are found in a large fraction of high fluence GRBs; fainter GRBs may not have sufficient statistics for deviations to be found using this method.

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“…Further motivation for broadband GRB spectroscopy comes from observations by BATSE of a spectral excess between 5 and 10 keV in ∼ 14% of GRBs [9,10], indicating the presence of an additional, possibly thermal, component to the synchrotron model. There is also evidence for a thermal component in the first stages of GRB emission which accompanies the underlying non-thermal emission [13,12,14] and which provides a natural explanation for the known correlation between peak energy and luminosity, since, for a thermal emitter, the luminosity and temperature are correlated.…”

Section: Introductionmentioning

confidence: 99%

Spectral and temporal properties of long GRBs detected by INTEGRAL from 3 keV to 8 MeV

Martín-Carrillo

Topinka

Hanlon

et al. 2011

Proceedings of 8th INTEGRAL Workshop “The Restless Gamma-Ray Universe” — PoS(INTEGRAL 2010)

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Since its launch in 2002, INTEGRAL has triggered on more than 78 γ-ray bursts in the 20-200 keV energy range with the IBIS/ISGRI instrument. Almost 30% of these bursts occurred within the fully coded field of view of the JEM-X detector (5 • ) which operates in the 3-35 keV energy range. A detailed study of the spectral and temporal evolution of a subset of 7 INTEGRAL γ-ray bursts across a wide energy range from 3 keV to 8 MeV has been carried out. This GRB sample is characterised by long multi-peaked bursts that are bright in the JEM-X energy range and encompass X-ray rich bursts, X-ray flashes and classical GRBs. We report the detection of X-ray prompt and afterglow emission from GRB 041219A and GRB 081003A with JEM-X for the first time. At least two temporal breaks have been identified in the X-ray afterglow light curve of GRB 081003A. These results demonstrate INTEGRAL's broadband capabilities for the study of the transition from X-ray prompt to afterglow emission in γ-ray bursts.

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BATSE Observations of Gamma‐Ray Burst Spectra. III. Low‐Energy Behavior of Time‐averaged Spectra

Cited by 59 publications

References 10 publications

Appearances of the jet photosphere in GRB spectra

Appearances of the jet photosphere in GRB spectra

Anomalies in low-energy gamma-ray burst spectra with theFermiGamma-ray Burst Monitor

Spectral and temporal properties of long GRBs detected by INTEGRAL from 3 keV to 8 MeV

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