Colour variations in the GRB 120327A afterglow

0485446 - ASÚ 2018 RIV FR eng J - Článek v odborném periodiku
Melandri, A. - Covino, S. - Zaninoni, E. - Campana, S. - Bolmer, J. - Cobb, B. E. - Gorosabel, J. - Kim, J.W. - Kuindersma, S. - Kuroda, D. - Malesani, D. - Mundell, C. G. - Nappo, F. - Sbarufatti, B. - Smith, R. J. - Steele, I.A. - Topinka, M. - Trotter, G. - Virgili, F. J. - Bernardini, M. G. - D'Avanzo, P. - D'Elia, V. - Fugazza, D. - Ghirlanda, G. - Gomboc, A. - Greiner, J. - Guidorzi, C. - Haislip, J.B. - Hanayama, H. - Hanlon, L. - Im, M. - Ivarsen, K.M. - Japelj, J. - Jelínek, Martin - Kawai, N. - Kobayashi, S. - Kopac, D. - LaCluyze, A. - Martin-Carrillo, A. - Murphy, D. - Reichart, D. E. - Salvaterra, R. - Salafia, O. S. - Tagliaferri, G. - Vergani, S. D.
Colour variations in the GRB 120327A afterglow.
Astronomy & Astrophysics. Roč. 607, October (2017), A29/1-A29/5. ISSN 0004-6361. E-ISSN 1432-0746
Institucionální podpora: RVO:67985815
Klíčová slova: gamma-ray burst * time-dependent photoionization * early optical afterglow
Obor OECD: Astronomy (including astrophysics,space science)
Impakt faktor: 5.565, rok: 2017

We present a comprehensive temporal and spectral analysis of the long Swift GRB120327A afterglow data to investigate possible causes of the observed early-time colour variations. We collected data from various instruments and telescopes in X-ray, ultraviolet, optical, and near-infrared bands, and determined the shapes of the afterglow early-time light curves. We studied the overall temporal behaviour and the spectral energy distributions from early to late times. The ultraviolet, optical, and near-infrared light curves can be modelled with a single power-law component between 200 and 2 x 10(4) s after the burst event. The X-ray light curve shows a canonical steep-shallow-steep behaviour that is typical of long gamma-ray bursts. At early times a colour variation is observed in the ultraviolet/optical bands, while at very late times a hint of a re-brightening is visible. The observed early-time colour change can be explained as a variation in the intrinsic optical spectral index, rather than an evolution of the optical extinction.

Trvalý link: http://hdl.handle.net/11104/0280475