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Title: TESTING THE MAGNETAR MODEL VIA LATE-TIME RADIO OBSERVATIONS OF TWO MACRONOVA CANDIDATES

Compact binary mergers may have already been observed as they are the leading model for short gamma-ray bursts (sGRBs). Radioactive decay within the ejecta from these mergers is expected to produce an infrared flare, dubbed macronova (or kilonova), on a timescale of a week. Recently, two such macronova candidates were identified in followup observations of sGRBs, strengthening the possibility that those indeed arise from mergers. The same ejecta will also produce long-term (months to years) radio emission due to its interaction with the surrounding interstellar medium. In the search for this emission, we observed the two macronova candidates, GRB 130603B and GRB 060614, with the Jansky Very Large Array (VLA) and the Australia Telescope Compact Array (ATCA). Our observations resulted in null-detections, putting strong upper limits on the kinetic energy and mass of the ejecta. A possible outcome of a merger is a highly magnetized neutron star (a magnetar), which has been suggested as the central engine for GRBs. Such a magnetar will deposit a significant fraction of its energy into the ejecta leading to a brighter radio flare. Our results, therefore, rule out magnetars in these two events.
Authors:
 [1] ; ;  [2] ;  [3] ;  [4]
  1. Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel)
  2. Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel)
  3. Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)
  4. International Centre for Radio Astronomy Research (ICRAR), Curtin University, GPO Box U1987, Perth WA 6845 (Australia)
Publication Date:
OSTI Identifier:
22518596
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 819; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; COSMIC GAMMA BURSTS; DETECTION; INTERSTELLAR SPACE; KINETIC ENERGY; MAGNETIC STARS; MASS; NEUTRON STARS; NUCLEAR DECAY; STELLAR FLARES; TELESCOPES