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Accueil > Séminaires > GW 170817 / GRB 170817A : the dawn (…)

GW 170817 / GRB 170817A : the dawn of a new era of multi-messenger and time-domain astronomy

Paolo D’Avanzo

The spectacular detection of the first electromagnetic counterpart of a gravitational wave event detected by the LIGO/Virgo intereferometers and originated by the coalescence of a double neutron star system (GW 170817) marked the dawn of a new era for astronomy. The (weak) short GRB 170817A associated to the GW event provided the long-sought evidence that at least a fraction of short GRBs are originated by NS-NS merging and suggested the intriguing possibility that relativistic jets can be launched in the process of a NS-NS merger. A world-wide extensive observing campaign was launched across the electromagnetic spectrum leading to the rapid (delta_t < 11 h) discovery of a bright UV/optical/NIR transient in the galaxy NGC 4993 (at 40 Mpc). The wealth of data collected provided the first compelling observational evidence for the existence of “kilonovae”, i.e. the emission due to radioactive decay of heavy nuclei produced through rapid neutron capture. A faint X-ray and radio counterpart was detected only at relatively late-times (9 and 16 days after the GW/GRB trigger, respectively), suggesting for the possibility of off-axis GRB afterglow emission.

In this talk I will present a review of the steps that led to this epocal result and discuss the implications and future perspectives for the newly-born era of multi-messenger astronomy