skip to main content


This content will become publicly available on August 14, 2018

Title: Behind the dust curtain: the spectacular case of GRB 160623A

Here, we report on the X-ray dust-scattering features observed around the afterglow of the gamma-ray burst GRB 160623A. With an XMM–Newton observation carried out ~2 d after the burst, we found evidence of at least six rings, with angular size expanding between ~2 and 9 arcmin, as expected for X-ray scattering of the prompt gamma-ray burst (GRB) emission by dust clouds in our Galaxy. From the expansion rate of the rings, we measured the distances of the dust layers with extraordinary precision: 528.1 ± 1.2, 679.2 ± 1.9, 789.0 ± 2.8, 952 ± 5, 1539 ± 20 and 5079 ± 64 pc. A spectral analysis of the ring spectra, based on an appropriate dust-scattering model (BARE-GR-B) and the estimated burst fluence, allowed us to derive the column density of the individual dust layers, which are in the range 7 × 10 20–1.5 × 10 22 cm –2. The farthest dust layer (i.e. the one responsible for the smallest ring) is also the one with the lowest column density and it is possibly very extended, indicating a diffuse dust region. The properties derived for the six dust layers (distance, thickness and optical depth) are generally in good agreement with independent informationmore » on the reddening along this line of sight and on the distribution of molecular and atomic gas.« less
ORCiD logo [1] ;  [2] ; ORCiD logo [1] ;  [3] ;  [1] ; ORCiD logo [4] ;  [5] ;  [1] ;  [6]
  1. INAF – IASF Milano, Milano (Italy)
  2. INAF – IASF Milano, Milano (Italy); Scuola Univ. Superiore IUSS Pavia, Pavia (Italy); Istituto Nazionale di Fisica Nucleare, Pavia (Italy)
  3. Stanford Univ., Stanford, CA (United States). SLAC National Accelerator Lab.
  4. Univ. of Amsterdam, Amsterdam (The Netherlands)
  5. SRON Netherlands Institute for Space Research, Utrecht (The Netherlands)
  6. Univ. of Zagreb, Zagreb (Croatia)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 472; Journal Issue: 2; Journal ID: ISSN 0035-8711
Royal Astronomical Society
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; scattering; gamma-ray burst: individual: GRB 160623A; dust; extinction; galaxies: haloes – X-rays: bursts; X-rays: ISM
OSTI Identifier: