Detailed afterglow modelling and host galaxy properties of the dark GRB 111215A
- A. J. van der Horst1,★,
- A. J. Levan2,
- G. G. Pooley3,
- K. Wiersema4,
- T. Krühler5,6,
- D. A. Perley7,†,
- R. L. C. Starling4,
- P. A. Curran8,
- N. R. Tanvir4,
- R. A. M. J. Wijers1,
- R. G. Strom9,
- C. Kouveliotou10,
- O. E. Hartoog1,
- D. Xu5,11,
- J. P. U. Fynbo5 and
- P. Jakobsson12
- 1Anton Pannekoek Institute, University of Amsterdam, Science Park 904, NL-1098 XH Amsterdam, the Netherlands
- 2Department of Physics, University of Warwick, Coventry CV4 7AL, UK
- 3Mullard Radio Astronomy Observatory, Cavendish Laboratory, The University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, UK
- 4Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK
- 5Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark
- 6European Southern Observatory, Alonso de Crdova 3107, Vitacura Casilla 19001, Santiago 19, Chile
- 7Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Blvd, Pasadena, CA 91125, USA
- 8International Centre for Radio Astronomy Research – Curtin University, GPO Box U1987, Perth, WA 6845, Australia
- 9ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, NL-7990 AA Dwingeloo, the Netherlands
- 10Space Science Office, ZP12, NASA/Marshall Space Flight Center, Huntsville, AL 35812, USA
- 11Department of Particle Physics and Astrophysics, Faculty of Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
- 12Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavík, Iceland
- ↵★E-mail: a.j.vanderhorst{at}uva.nl
- Accepted 2014 November 12.
- Received 2014 October 21.
- In original form 2014 August 18.
- First published online December 10, 2014.
Abstract
Gamma-ray burst (GRB) 111215A was bright at X-ray and radio frequencies, but not detected in the optical or near-infrared (nIR) down to deep limits. We have observed the GRB afterglow with the Westerbork Synthesis Radio Telescope and Arcminute Microkelvin Imager at radio frequencies, with the William Herschel Telescope and Nordic Optical Telescope in the nIR/optical, and with the Chandra X-ray Observatory. We have combined our data with the Swift X-Ray Telescope monitoring, and radio and millimetre observations from the literature to perform broad-band modelling, and determined the macro- and microphysical parameters of the GRB blast wave. By combining the broad-band modelling results with our nIR upper limits we have put constraints on the extinction in the host galaxy. This is consistent with the optical extinction we have derived from the excess X-ray absorption, and higher than in other dark bursts for which similar modelling work has been performed. We also present deep imaging of the host galaxy with the Keck I telescope, Spitzer Space Telescope, and Hubble Space Telescope (HST), which resulted in a well-constrained photometric redshift, giving credence to the tentative spectroscopic redshift we obtained with the Keck II telescope, and estimates for the stellar mass and star formation rate of the host. Finally, our high-resolution HST images of the host galaxy show that the GRB afterglow position is offset from the brightest regions of the host galaxy, in contrast to studies of optically bright GRBs.
Key words
- © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
