Year: 2019
Type: article
Abstract: We present observations of the possible short GRB 180418A in γ-rays, X-rays, and in the optical. Early optical photometry with the TAROT and RATIR instruments shows a bright peak (≈14.2 AB mag) between T + 28 and T + 90 s that we interpret as the signature of a reverse shock. Later observations can be modeled by a standard forward shock model and show no evidence of a jet break, allowing us to constrain the jet collimation to θ j > 7°. Using deep late-time optical observations, we place an upper limit of r > 24 AB mag on any underlying host galaxy. The detection of the afterglow in the Swift UV filters constrains the GRB redshift to z < 1.3 and places an upper bound on the γ-ray isotropic equivalent energy E γ,iso < 3 × 1051 erg. The properties of this GRB (e.g., duration, hardness ratio, energy, and environment) lie at the intersection between short and long bursts, and we cannot conclusively identify its type. We estimate that the probability that it is drawn from the population of short GRBs is 10%–30%.
Source: The Astrophysical Journal
Authors: R. L. Becerra, S. Dichiara, A. M. Watson, E. Troja, N. Fraija, A. Klotz, N. R. Butler, W. H. Lee, P. Veres, D. Turpin, J. S. Bloom, M. Boer, J. J. González, A. S. Kutyrev, J. X. Prochaska, E. Ramirez-Ruiz, M. G. Richer
Institutions: Universidad Nacional Autónoma de México, Goddard Space Flight Center, University of Maryland, College Park, Institut de Recherche en Astrophysique et Planétologie, Arizona State University, University of Alabama in Huntsville, Chinese Academy of Sciences, National Astronomical Observatories, Centre National de la Recherche Scientifique, Astrophysique Relativiste, Théories, Expériences, Métrologie, Instrumentation, Signaux, Observatoire de la Côte d’Azur, University of California, Santa Cruz
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Aeronautics and Space Administration, University of California Institute for Mexico and the United States, Arizona State University, Centre National d’Etudes Spatiales, Centre National de la Recherche Scientifique, Goddard Space Flight Center, Institut national des sciences de l'Univers
Awards: THE REIONIZATION AND TRANSIENTS IR CAMERA; A HIGH Z GRB SEARCH MACHINE: THE 1.5 METER TELESCOPE WE PROPOSE TO USE IS LOCATED AT THE MEXICAN OBSERVAT, THE REIONIZATION AND TRANSIENTS IR CAMERA: A HIGH-Z GRB SEARCH MACHINE WE PROPOSE TO BUILD AND OPERATE IN CYCLE 5 THE REIONIZATION AND TRANSIENTS IN, WITH SUBSTANTIAL FUNDS FROM THE SWIFT CYCLE 5 GUEST INVESTIGATOR PROGRAM, WE ARE NOW BUILDING THE REIONIZATION AND TRANSIENTS INFRARED (RATIR) CAMERA, G8617474680, WITH SUBSTANTIAL FUNDS FROM THE SWIFT CYCLES 5 AND 6 GUEST INVESTIGATOR PROGRAM, WE ARE NOW BUILDING THE REIONIZATION AND TRANSIENTS INFRARED (RATIR)
OpenAlex ID: W2939219732