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Title: RADIO FLARES FROM GAMMA-RAY BURSTS

We present predictions of centimeter and millimeter radio emission from reverse shocks (RSs) in the early afterglows of gamma-ray bursts (GRBs) with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy, and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parameterization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. and Melandri et al. in which the typical frequency of the RS was suggested to lie at radio rather than optical wavelengths at early times, we show that the brightest and most distinct RS radio signatures are detectable up to 0.1–1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later optical peaks, high isotropic energies, lower circumburst medium densities, and at observing frequencies that are less prone to synchrotron self-absorption effects—typically above a few GHz. Given recent detections of polarized prompt gamma-ray and optical RS emission, we suggest that detection of polarized radio/millimeter emissionmore » will unambiguously confirm the presence of low-frequency RSs at early time.« less
Authors:
; ; ;  [1] ;  [2] ; ;  [3] ;  [4] ;  [5]
  1. Astrophysics Research Institute, Liverpool John Moores University, Liverpool, L3 5RF (United Kingdom)
  2. Department of Astrophysics, School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel)
  3. Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia)
  4. Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1, I-44122 Ferrara (Italy)
  5. INAF/Brera Astronomical Observatory, via Bianchi 46, I-23807, Merate (Italy)
Publication Date:
OSTI Identifier:
22522285
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 806; 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; AFTERGLOW; BRIGHTNESS; COSMIC GAMMA BURSTS; COSMIC RADIO SOURCES; DENSITY; DETECTION; DIAGRAMS; EMISSION SPECTRA; GAMMA RADIATION; GHZ RANGE; RED SHIFT; SELF-ABSORPTION; VISIBLE RADIATION