Seminar:- On The First 5 Seconds Post GW170817 

GRB170817A is a short gamma-ray burst with 2.9s soft emission over 8-70 keV subsequent to the double neutron star merger GW170817. It is LIGO's first entry into multi-messenger astronomy, following the seminal detection of GW150914 that was honored with last year's Nobel Prize of Physics. GRB170817A is produced by prompt or continuous output from a newly formed hypermassive eutron star (HNS) or stellar mass black hole (BH). In chirp-based spectrograms up to 700Hz, we report on a descending chirp in gravitational wave emission during GRB170817A with characteristic time scale of 3s. Starting in the 1.7s gap between GW170817 and GRB170817A, its significance to the central engine has a Gaussian equivalent level of 3.29σ by causality alone that increases to 4.31σ by image analysis (2.4σ). At frequencies below 1kHz, this signal indicates a HNS rather than a BH, spinning down by magnetic winds and interactions with dynamical mass ejecta. In the upcoming LIGO-Virgo O3, possibly jointly with KAGRA, this analysis is proposed to search for the central engine also of nearby core-collapse supernovae.
時間:2018.06.15(五) 14:30 ~ 15:15
地點:香港中文大學 科學館北座G25室
講者:Prof. Maurice VAN PUTTEN(南韓世宗大學天文系)



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