Multi-messenger Observations of a Binary Neutron Star Merger

A. MARIAZZI; THE PIERRE AUGER COLLABORATION; LIGO SCIENTIFIC COLLABORATION AND VIRGO COLLABORATION, FERMI GBM, INTEGRAL, ICECUBE COLLABORATION, ASTROSAT CADMIUM ZINC TELLURIDE IMAGER TEAM, IPN COLLABORATION, THE INSIGHT-HXMT COLLABORATION, ANTARES COLLABORATION, THE SWIFT COLLABORATION, AGILE TEAM; THE 1M2H TEAM, THE DARK ENERGY CAMERA GW-EM COLLABORATION AND THE DES COLLABORATION, THE DLT40 COLLABORATION, GRAWITA: GRAVITATIONAL WAVE INAF TEAM, THE FERMI LARGE AREA TELESCOPE COLLABORATION, ATCA: AUSTRALIA TELESCOPE COMPACT ARRAY; ASKAP: AUSTRALIAN SKA PATHFINDER, LAS CUMBRES OBSERVATORY GROUP, OZGRAV, DWF (DEEPER, WIDER, FASTER PROGRAM), AST3, AND CAASTRO COLLABORATIONS, THE VINROUGE COLLABORATION, MASTER COLLABORATION, J-GEM, GROWTH, JAGWAR; CALTECH- NRAO, TTU-NRAO, AND NUSTAR COLLABORATIONS, PAN-STARRS, THE MAXI TEAM, TZAC CONSORTIUM, KU COLLABORATION, NORDIC OPTICAL TELESCOPE, EPESSTO, GROND, TEXAS TECH UNIVERSITY, SALT GROUP; TOROS: TRANSIENT ROBOTIC OBSERVATORY OF THE SOUTH COLLABORATION, THE BOOTES COL

The Astrophysica Journal Letters

Institute of physics (IOP)

Año: 2017 vol. 848

2041-8213

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $sim 1.7,{m{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $,{M}_{odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $sim 40,{m{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient´s position $sim 9$ and $sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.