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Title: DISCOVERY AND REDSHIFT OF AN OPTICAL AFTERGLOW IN 71 deg{sup 2}: iPTF13bxl AND GRB 130702A

We report the discovery of the optical afterglow of the γ-ray burst (GRB) 130702A, identified upon searching 71 deg{sup 2} surrounding the Fermi Gamma-ray Burst Monitor (GBM) localization. Discovered and characterized by the intermediate Palomar Transient Factory, iPTF13bxl is the first afterglow discovered solely based on a GBM localization. Real-time image subtraction, machine learning, human vetting, and rapid response multi-wavelength follow-up enabled us to quickly narrow a list of 27,004 optical transient candidates to a single afterglow-like source. Detection of a new, fading X-ray source by Swift and a radio counterpart by CARMA and the Very Large Array confirmed the association between iPTF13bxl and GRB 130702A. Spectroscopy with the Magellan and Palomar 200 inch telescopes showed the afterglow to be at a redshift of z = 0.145, placing GRB 130702A among the lowest redshift GRBs detected to date. The prompt γ-ray energy release and afterglow luminosity are intermediate between typical cosmological GRBs and nearby sub-luminous events such as GRB 980425 and GRB 060218. The bright afterglow and emerging supernova offer an opportunity for extensive panchromatic follow-up. Our discovery of iPTF13bxl demonstrates the first observational proof-of-principle for ∼10 Fermi-iPTF localizations annually. Furthermore, it represents an important step toward overcoming the challengesmore » inherent in uncovering faint optical counterparts to comparably localized gravitational wave events in the Advanced LIGO and Virgo era.« less
Authors:
;  [1] ; ; ;  [2] ; ;  [3] ; ; ; ; ; ;  [4] ; ;  [5] ; ;  [6] ;  [7] ;  [8] ;  [9] more »; « less
  1. LIGO Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States)
  2. Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States)
  3. Observatories of the Carnegie Institution for Science, 813 Santa Barbara St, Pasadena, CA 91101 (United States)
  4. Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
  5. Benoziyo Center for Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel)
  6. Department of Astronomy, University of California Berkeley, B-20 Hearst Field Annex 3411, Berkeley, CA 94720-3411 (United States)
  7. George Washington University, Corcoran Hall, Washington, DC 20052 (United States)
  8. National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States)
  9. Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)
Publication Date:
OSTI Identifier:
22215428
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 776; 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; COSMIC GAMMA BURSTS; DETECTION; GRAVITATIONAL WAVES; IMAGES; LUMINOSITY; RED SHIFT; SPECTROSCOPY; TELESCOPES; TRANSIENTS; WAVELENGTHS; X-RAY SOURCES