Observational evidence for extended emission to GW170817

DOI: 
10.1093/mnrasl/sly166
Publication date: 
16/01/2019
Main author: 
van Putten M.H.P.M.
IAA authors: 
Valle, M.D.
Authors: 
van Putten M.H.P.M., Valle M.D.
Journal: 
Monthly Notices of the Royal Astronomical Society: Letters
Refereed: 
Yes
Publication type: 
Article
Volume: 
482
Pages: 
L46-L49
Abstract: 
The recent LIGO event GW170817 is the merger of a double neutron star system with an associated short GRB170817A with 2.9 ± 0.3 s soft emission over 8-70 keV. This association has a Gaussian equivalent level of confidence of 5.1σ. The merger produced a hypermassive neutron star or stellar mass black hole with prompt or continuous energy output powering GRB170817A. Here, we report on a possible detection of extended emission (EE) in gravitational radiation during GRB170817A: a descending chirp with characteristic time-scale τs = 3.01 ± 0.2 s in a (H1,L1)-spectrogram up to 700 Hz with Gaussian equivalent level of confidence greater than 3.3σ based on causality alone following edge detection applied to (H1,L1)-spectrograms merged by frequency coincidences. Additional confidence derives from the strength of this EE. The observed frequencies below 1 kHz indicate a hypermassive magnetar rather than a black hole, spinning down by magnetic winds and interactions with dynamical mass ejecta. © 2018 The Author(s).
Database: 
SCOPUS
ADS
URL: 
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85057142122&doi=10.1093%2fmnrasl%2fsly166&partnerID=40&md5=1d7acfb335012d7a587dbc9974c2b608
ADS Bibcode: 
2019MNRAS.482L..46V
Keywords: 
Gamma-ray bursts: individual: GRB170817A; Gravitational waves; Methods: data-analysis; Stars: neutron