X-shooter and ALMA spectroscopy of GRB 161023A - A study of metals and molecules in the line of sight towards a luminous GRB

A. de Ugarte Postigo, C. C. Thöne, J. Bolmer, S. Schulze, S. Martín, D. A. Kann, V. D'Elia, J. Selsing, A. Martin-Carrillo, D. A. Perley, S. Kim, L. Izzo, R. Sánchez-Ramírez, C. Guidorzi, A. Klotz, K. Wiersema, F. E. Bauer, K. Bensch, S. Campana, Z. CanoS. Covino, D. Coward, A. De Cia, I. de Gregorio-Monsalvo, M. De Pasquale, J. P. U. Fynbo, J. Greiner, A. Gomboc, L. Hanlon, M. Hansen, D. H. Hartmann, K. E. Heintz, P. Jakobsson, S. Kobayashi, D. B. Malesani, R. Martone, P. J. Meintjes, M. J. Michalowski, C. G. Mundell, D. Murphy, S. Oates, L. Resmi, L. Salmon, B. van Soelen, N. R. Tanvir, D. Turpin, D. Xu, T. Zafar

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18 Citations (SciVal)


Long gamma-ray bursts are produced during the dramatic deaths of massive stars with very short lifetimes, meaning that they explode close to the birth place of their progenitors. During a short period they become the most luminous objects observable in the Universe, being perfect beacons to study high-redshift star-forming regions. To use the afterglow of GRB 161023A at a redshift $z=2.710$ as a background source to study the environment of the explosion and the intervening systems along its line-of-sight. r the first time, we complement UV/Optical/NIR spectroscopy with millimetre spectroscopy using ALMA, which allows us to probe the molecular content of the host galaxy. The X-shooter spectrum shows a plethora of absorption features including fine-structure and metastable transitions of Fe, Ni, Si, C and O. We present photometry ranging from 43 s to over 500 days after the burst. We infer a host-galaxy metallicity of [Zn/H] $=-1.11\pm0.07$, which corrected for dust depletion results in [X/H] $=-0.94\pm0.08$. We do not detect molecular features in the ALMA data, but we derive limits on the molecular content of $log(N_{CO}/cm^{-2})
Original languageEnglish
Article numberA119
Number of pages23
JournalAstronomy & Astrophysics
Early online date7 Dec 2018
Publication statusPublished - 7 Dec 2018

Bibliographical note

28 pages, 19 pages main text, 9 pages appendix; accepted for publication in A&A


  • astro-ph.HE


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