A faint optical flash in dust-obscured GRB 080603A: Implications for GRB prompt emission mechanisms

C. Guidorzi, S. Kobayashi, D. A. Perley, G. Vianello, J. S. Bloom, P. Chandra, D. A. Kann, W. Li, C. G. Mundell, A. Pozanenko, J. X. Prochaska, K. Antoniuk, D. Bersier, A. V. Filippenko, D. A. Frail, A. Gomboc, E. Klunko, A. Melandri, S. Mereghetti, A. N. MorganP. T. O'Brien, V. Rumyantsev, R. J. Smith, I. A. Steele, N. R. Tanvir, A. Volnova

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

We report the detection of a faint optical flash by the 2-m Faulkes Telescope North simultaneously with the second of two prompt γ-ray pulses in INTEGRAL gamma-ray burst (GRB) 080603A, beginning at trest= 37s after the onset of the GRB. This optical flash appears to be distinct from the subsequent emerging afterglow emission, for which we present comprehensive broad-band radio to X-ray light curves to 13d post-burst and rigorously test the standard fireball model. The intrinsic extinction towards GRB 080603A is high (AV, z= 0.8mag), and the well-sampled X-ray-to-near-infrared spectral energy distribution is interesting in requiring an LMC2 extinction profile, in contrast to the majority of GRBs. Comparison of the γ-ray and extinction-corrected optical flux densities of the flash rules out an inverse-Compton origin for the prompt γ-rays; instead, we suggest that the optical flash could originate from the inhomogeneity of the relativistic flow. In this scenario, a large velocity irregularity in the flow produces the prompt γ-rays, followed by a milder internal shock at a larger radius that would cause the optical flash. Flat γ-ray spectra, roughly F∝ν-0.1, are observed in many GRBs. If the flat spectrum extends down to the optical band in GRB 080603A, the optical flare could be explained as the low-energy tail of the γ-ray emission. If this is indeed the case, it provides an important clue to understanding the nature of the emission process in the prompt phase of GRBs and highlights the importance of deep (R > 20mag), rapid follow-up observations capable of detecting faint, prompt optical emission.

Original languageEnglish
Pages (from-to)2124-2143
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Volume417
Issue number3
DOIs
Publication statusPublished - 1 Nov 2011

Fingerprint

gamma ray bursts
flash
dust
gamma rays
extinction
burst tests
inhomogeneity
fireballs
gamma ray spectra
energy
near infrared
spectral energy distribution
afterglows
irregularities
flares
light curve
light emission
radio
emerging
x rays

Keywords

  • Gamma-ray burst: individual: GRB 080603A
  • Radiation mechanisms: non-thermal

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Guidorzi, C., Kobayashi, S., Perley, D. A., Vianello, G., Bloom, J. S., Chandra, P., ... Volnova, A. (2011). A faint optical flash in dust-obscured GRB 080603A: Implications for GRB prompt emission mechanisms. Monthly Notices of the Royal Astronomical Society, 417(3), 2124-2143. https://doi.org/10.1111/j.1365-2966.2011.19394.x

A faint optical flash in dust-obscured GRB 080603A : Implications for GRB prompt emission mechanisms. / Guidorzi, C.; Kobayashi, S.; Perley, D. A.; Vianello, G.; Bloom, J. S.; Chandra, P.; Kann, D. A.; Li, W.; Mundell, C. G.; Pozanenko, A.; Prochaska, J. X.; Antoniuk, K.; Bersier, D.; Filippenko, A. V.; Frail, D. A.; Gomboc, A.; Klunko, E.; Melandri, A.; Mereghetti, S.; Morgan, A. N.; O'Brien, P. T.; Rumyantsev, V.; Smith, R. J.; Steele, I. A.; Tanvir, N. R.; Volnova, A.

In: Monthly Notices of the Royal Astronomical Society, Vol. 417, No. 3, 01.11.2011, p. 2124-2143.

Research output: Contribution to journalArticle

Guidorzi, C, Kobayashi, S, Perley, DA, Vianello, G, Bloom, JS, Chandra, P, Kann, DA, Li, W, Mundell, CG, Pozanenko, A, Prochaska, JX, Antoniuk, K, Bersier, D, Filippenko, AV, Frail, DA, Gomboc, A, Klunko, E, Melandri, A, Mereghetti, S, Morgan, AN, O'Brien, PT, Rumyantsev, V, Smith, RJ, Steele, IA, Tanvir, NR & Volnova, A 2011, 'A faint optical flash in dust-obscured GRB 080603A: Implications for GRB prompt emission mechanisms', Monthly Notices of the Royal Astronomical Society, vol. 417, no. 3, pp. 2124-2143. https://doi.org/10.1111/j.1365-2966.2011.19394.x
Guidorzi, C. ; Kobayashi, S. ; Perley, D. A. ; Vianello, G. ; Bloom, J. S. ; Chandra, P. ; Kann, D. A. ; Li, W. ; Mundell, C. G. ; Pozanenko, A. ; Prochaska, J. X. ; Antoniuk, K. ; Bersier, D. ; Filippenko, A. V. ; Frail, D. A. ; Gomboc, A. ; Klunko, E. ; Melandri, A. ; Mereghetti, S. ; Morgan, A. N. ; O'Brien, P. T. ; Rumyantsev, V. ; Smith, R. J. ; Steele, I. A. ; Tanvir, N. R. ; Volnova, A. / A faint optical flash in dust-obscured GRB 080603A : Implications for GRB prompt emission mechanisms. In: Monthly Notices of the Royal Astronomical Society. 2011 ; Vol. 417, No. 3. pp. 2124-2143.
@article{43d6fe49e50440c0829f3eb4bbd4aa97,
title = "A faint optical flash in dust-obscured GRB 080603A: Implications for GRB prompt emission mechanisms",
abstract = "We report the detection of a faint optical flash by the 2-m Faulkes Telescope North simultaneously with the second of two prompt γ-ray pulses in INTEGRAL gamma-ray burst (GRB) 080603A, beginning at trest= 37s after the onset of the GRB. This optical flash appears to be distinct from the subsequent emerging afterglow emission, for which we present comprehensive broad-band radio to X-ray light curves to 13d post-burst and rigorously test the standard fireball model. The intrinsic extinction towards GRB 080603A is high (AV, z= 0.8mag), and the well-sampled X-ray-to-near-infrared spectral energy distribution is interesting in requiring an LMC2 extinction profile, in contrast to the majority of GRBs. Comparison of the γ-ray and extinction-corrected optical flux densities of the flash rules out an inverse-Compton origin for the prompt γ-rays; instead, we suggest that the optical flash could originate from the inhomogeneity of the relativistic flow. In this scenario, a large velocity irregularity in the flow produces the prompt γ-rays, followed by a milder internal shock at a larger radius that would cause the optical flash. Flat γ-ray spectra, roughly F∝ν-0.1, are observed in many GRBs. If the flat spectrum extends down to the optical band in GRB 080603A, the optical flare could be explained as the low-energy tail of the γ-ray emission. If this is indeed the case, it provides an important clue to understanding the nature of the emission process in the prompt phase of GRBs and highlights the importance of deep (R > 20mag), rapid follow-up observations capable of detecting faint, prompt optical emission.",
keywords = "Gamma-ray burst: individual: GRB 080603A, Radiation mechanisms: non-thermal",
author = "C. Guidorzi and S. Kobayashi and Perley, {D. A.} and G. Vianello and Bloom, {J. S.} and P. Chandra and Kann, {D. A.} and W. Li and Mundell, {C. G.} and A. Pozanenko and Prochaska, {J. X.} and K. Antoniuk and D. Bersier and Filippenko, {A. V.} and Frail, {D. A.} and A. Gomboc and E. Klunko and A. Melandri and S. Mereghetti and Morgan, {A. N.} and O'Brien, {P. T.} and V. Rumyantsev and Smith, {R. J.} and Steele, {I. A.} and Tanvir, {N. R.} and A. Volnova",
year = "2011",
month = "11",
day = "1",
doi = "10.1111/j.1365-2966.2011.19394.x",
language = "English",
volume = "417",
pages = "2124--2143",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "3",

}

TY - JOUR

T1 - A faint optical flash in dust-obscured GRB 080603A

T2 - Implications for GRB prompt emission mechanisms

AU - Guidorzi, C.

AU - Kobayashi, S.

AU - Perley, D. A.

AU - Vianello, G.

AU - Bloom, J. S.

AU - Chandra, P.

AU - Kann, D. A.

AU - Li, W.

AU - Mundell, C. G.

AU - Pozanenko, A.

AU - Prochaska, J. X.

AU - Antoniuk, K.

AU - Bersier, D.

AU - Filippenko, A. V.

AU - Frail, D. A.

AU - Gomboc, A.

AU - Klunko, E.

AU - Melandri, A.

AU - Mereghetti, S.

AU - Morgan, A. N.

AU - O'Brien, P. T.

AU - Rumyantsev, V.

AU - Smith, R. J.

AU - Steele, I. A.

AU - Tanvir, N. R.

AU - Volnova, A.

PY - 2011/11/1

Y1 - 2011/11/1

N2 - We report the detection of a faint optical flash by the 2-m Faulkes Telescope North simultaneously with the second of two prompt γ-ray pulses in INTEGRAL gamma-ray burst (GRB) 080603A, beginning at trest= 37s after the onset of the GRB. This optical flash appears to be distinct from the subsequent emerging afterglow emission, for which we present comprehensive broad-band radio to X-ray light curves to 13d post-burst and rigorously test the standard fireball model. The intrinsic extinction towards GRB 080603A is high (AV, z= 0.8mag), and the well-sampled X-ray-to-near-infrared spectral energy distribution is interesting in requiring an LMC2 extinction profile, in contrast to the majority of GRBs. Comparison of the γ-ray and extinction-corrected optical flux densities of the flash rules out an inverse-Compton origin for the prompt γ-rays; instead, we suggest that the optical flash could originate from the inhomogeneity of the relativistic flow. In this scenario, a large velocity irregularity in the flow produces the prompt γ-rays, followed by a milder internal shock at a larger radius that would cause the optical flash. Flat γ-ray spectra, roughly F∝ν-0.1, are observed in many GRBs. If the flat spectrum extends down to the optical band in GRB 080603A, the optical flare could be explained as the low-energy tail of the γ-ray emission. If this is indeed the case, it provides an important clue to understanding the nature of the emission process in the prompt phase of GRBs and highlights the importance of deep (R > 20mag), rapid follow-up observations capable of detecting faint, prompt optical emission.

AB - We report the detection of a faint optical flash by the 2-m Faulkes Telescope North simultaneously with the second of two prompt γ-ray pulses in INTEGRAL gamma-ray burst (GRB) 080603A, beginning at trest= 37s after the onset of the GRB. This optical flash appears to be distinct from the subsequent emerging afterglow emission, for which we present comprehensive broad-band radio to X-ray light curves to 13d post-burst and rigorously test the standard fireball model. The intrinsic extinction towards GRB 080603A is high (AV, z= 0.8mag), and the well-sampled X-ray-to-near-infrared spectral energy distribution is interesting in requiring an LMC2 extinction profile, in contrast to the majority of GRBs. Comparison of the γ-ray and extinction-corrected optical flux densities of the flash rules out an inverse-Compton origin for the prompt γ-rays; instead, we suggest that the optical flash could originate from the inhomogeneity of the relativistic flow. In this scenario, a large velocity irregularity in the flow produces the prompt γ-rays, followed by a milder internal shock at a larger radius that would cause the optical flash. Flat γ-ray spectra, roughly F∝ν-0.1, are observed in many GRBs. If the flat spectrum extends down to the optical band in GRB 080603A, the optical flare could be explained as the low-energy tail of the γ-ray emission. If this is indeed the case, it provides an important clue to understanding the nature of the emission process in the prompt phase of GRBs and highlights the importance of deep (R > 20mag), rapid follow-up observations capable of detecting faint, prompt optical emission.

KW - Gamma-ray burst: individual: GRB 080603A

KW - Radiation mechanisms: non-thermal

UR - http://www.scopus.com/inward/record.url?scp=80055119660&partnerID=8YFLogxK

U2 - 10.1111/j.1365-2966.2011.19394.x

DO - 10.1111/j.1365-2966.2011.19394.x

M3 - Article

AN - SCOPUS:80055119660

VL - 417

SP - 2124

EP - 2143

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 3

ER -