GRB 090313 AND THE ORIGIN OF OPTICAL PEAKS IN GAMMA-RAY BURST LIGHT CURVES: IMPLICATIONS FOR LORENTZ FACTORS AND RADIO FLARES

Journal Article · Wed Nov 10 00:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/723/2/1331· OSTI ID:21471258

Melandri, A; Kobayashi, S; Mundell, C G; Guidorzi, C; Bersier, D; Steele, I A; Smith, R J ^[1]; De Ugarte Postigo, A ^[2]; Pooley, G ^[3]; Yoshida, M ^[4]; Castro-Tirado, A J; Gorosabel, J; Kubanek, P; Sota, A ^[5]; JelInek, M ^[6]; Gomboc, A ^[7]; Bremer, M; Winters, J M ^[8]; De Gregorio-Monsalvo, I; GarcIa-Appadoo, D ^[9]

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1. Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead, CH41 1LD (United Kingdom)
2. INAF Osservatorio Astronomico di Brera, via Bianchi 46, 23807 Merate (Saint Lucia) (Italy)
3. Mullard Radio Astronomy Observatory, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE (United Kingdom)
4. Okoyama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama 719-0232 (Japan)
5. Instituto de AstrofisIca de AndalucIa (CSIC), Glorieta de la Astronomia s/n, E-18080 Granada (Spain)
6. Hiroshima Astrophysical Science Center, Hiroshima University 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)
7. Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana (Slovenia)
8. Institut de Radioastronomie Millimetrique, 300 rue de la Piscine, 38406 St. Martin d'Heres (France)
9. European Southern Observatory, Casilla 19001, Santiago 19 (Chile)

We use a sample of 19 gamma-ray bursts (GRBs) that exhibit single-peaked optical light curves to test the standard fireball model by investigating the relationship between the time of the onset of the afterglow and the temporal rising index. Our sample includes GRBs and X-ray flashes for which we derive a wide range of initial Lorentz factors (40 < {Gamma} < 450). Using plausible model parameters, the typical frequency of the forward shock is expected to lie close to the optical band; within this low typical frequency framework, we use the optical data to constrain {epsilon}{sub e} and show that values derived from the early time light-curve properties are consistent with published typical values derived from other afterglow studies. We produce expected radio light curves by predicting the temporal evolution of the expected radio emission from forward and reverse shock components, including synchrotron self-absorption effects at early time. Although a number of GRBs in this sample do not have published radio measurements, we demonstrate the effectiveness of this method in the case of Swift GRB 090313, for which millimetric and centimetric observations were available, and conclude that future detections of reverse-shock radio flares with new radio facilities such as the EVLA and ALMA will test the low-frequency model and provide constraints on magnetic models.

• OSTI ID: 21471258
• Journal Information: Astrophysical Journal, Vol. 723, Issue 2; Other Information: DOI: 10.1088/0004-637X/723/2/1331; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
AFTERGLOW
COSMIC GAMMA BURSTS
FIREBALL MODEL
GALACTIC EVOLUTION
SELF-ABSORPTION
VISIBLE RADIATION
ABSORPTION
COSMIC RADIATION
ELECTROMAGNETIC RADIATION
EVOLUTION
IONIZING RADIATIONS
MATHEMATICAL MODELS
PARTICLE MODELS
PRIMARY COSMIC RADIATION
RADIATIONS
SORPTION