journal contribution posted on 04.01.2017, 16:01 by R. Sánchez-Ramírez, P. J. Hancock, G. Jóhannesson, Tara Murphy, A. de Ugarte Postigo, J. Gorosabel, D. A. Kann, T. Krühler, S. R. Oates, J. Japelj, C. C. Thöne, A. Lundgren, D. A. Perley, D. Malesani, I. de Gregorio Monsalvo, A. J. Castro-Tirado, V. D'Elia, J. P. U. Fynbo, D. Garcia-Appadoo, P. Goldoni, J. Greiner, Y.-D. Hu, M. Jelínek, S. Jeong, A. Kamble, S. Klose, N. P. M. Kuin, A. Llorente, S. Martín, A. Nicuesa Guelbenzu, A. Rossi, P. Schady, M. Sparre, V. Sudilovsky, J. C. Tello, A. Updike, K. Wiersema, B.-B. Zhang
We present the extensive follow-up campaign on the afterglow of GRB 110715A at 17 different wavelengths, from X-ray to radio bands, starting 81 s after the burst and extending up to 74 d later. We performed for the first time a GRB afterglow observation with the ALMA observatory. We find that the afterglow of GRB 110715A is very bright at optical and radio wavelengths. We use the optical and near-infrared spectroscopy to provide further information about the progenitor's environment and its host galaxy. The spectrum shows weak absorption features at a redshift z = 0.8225, which reveal a host-galaxy environment with low ionization, column density, and dynamical activity. Late deep imaging shows a very faint galaxy, consistent with the spectroscopic results. The broad-band afterglow emission is modelled with synchrotron radiation using a numerical algorithm and we determine the best-fitting parameters using Bayesian inference in order to constrain the physical parameters of the jet and the medium in which the relativistic shock propagates. We fitted our data with a variety of models, including different density profiles and energy injections. Although the general behaviour can be roughly described by these models, none of them are able to fully explain all data points simultaneously. GRB 110715A shows the complexity of reproducing extensive multiwavelength broad-band afterglow observations, and the need of good sampling in wavelength and time and more complex models to accurately constrain the physics of GRB afterglows.
RSR is grateful
to SEPE for financial support while finishing this work and his
PhD thesis. RSR, SRO, AJCT, YDH, SJ, and JCT acknowledge the
financial support of the Spanish Government projects AYA 2009-
14000-C03-01 and AYA 2012-39727-C03-01. Parts of this research
were conducted by the Australian Research Council Centre of Excellence
for All-sky Astrophysics (CAASTRO), through project No.
CE110001020. AdUP and CT acknowledge support from Ramon´
y Cajal fellowships and from the Spanish research project AYA
2014-58381. JJ acknowledges financial contribution from the grant
PRIN MIUR 2012 201278X4FL 002 ‘The Intergalactic Medium as
a probe of the growth of cosmic structures’. DAK acknowledges the
financial support by MPE Garching and TLS Tautenburg. Part of the
funding for GROND (both hardware as well as personnel) was generously
granted from the Leibniz-Prize to Prof. G. Hasinger (DFG
grant HA 1850/28-1). PS and TK acknowledges support through
the Sofja Kovalevskaja Award to P. Schady from the Alexander von
Humboldt Foundation of Germany. AU is grateful for travel funding
support through the Max-Planck Inst. for Extraterrestrial Physics.
SK and ANG acknowledge support by DFG grant Kl 766/16-1.
This work made use of data supplied by the UK Swift Science Data
Centre at the University of Leicester.
Facilities: This publication is based on data acquired with the
Atacama Pathfinder Experiment (APEX) under program 087.F-
9301(A). This paper makes use of the following ALMA data:
ADS/JAO.ALMA#2011.0.00001.E. ALMA is a partnership of ESO
(representing its member states), NSF (USA) and NINS (Japan), together
with NRC (Canada), NSC and ASIAA (Taiwan), and KASI
(Republic of Korea), in cooperation with the Republic of Chile.
The Joint ALMA Observatory is operated by ESO, AUI/NRAO and
NAOJ. This publication is based on data acquired with the VLT/Xshooter
under program 087.A-0055(C), as well as with VLT/FORS2
under program 091.A-0703(A).
CitationMonthly Notices of the Royal Astronomical Society, 2016, 464 (4), pp. 4624-4640
Author affiliation/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy
VersionVoR (Version of Record)
Published inMonthly Notices of the Royal Astronomical Society
PublisherOxford University Press (OUP), Royal Astronomical Society