A Systematic Exploration of Kilonova Candidates from Neutron Star Mergers during the Third Gravitational-wave Observing Run

Abstract We present a comprehensive analysis of 653 optical candidate counterparts reported during the third gravitational-wave (GW) observing run. Our sample concentrates on candidates from the 15 events (published in GWTC-2, GWTC-3, or not retracted on GraceDB) that had a >1% chance of includin...

Full description

Saved in:
Bibliographic Details
Published in:The Astrophysical journal 2022-03, Vol.927 (1), p.50
Main Authors: Rastinejad, J. C., Paterson, K., Fong, W., Sand, D. J., Lundquist, M. J., Hosseinzadeh, G., Christensen, E., Daly, P. N., Gibbs, A. R., Hall, S., Shelly, F., Yang, S.
Format: Article
Language:English
Subjects:
Astronomy & Astrophysics
ASTRONOMY AND ASTROPHYSICS
Astrophysics
Candidates
Celestial bodies
Galaxies
Gravitational wave astronomy
Gravitational waves
Kilonovae
Neutron stars
Photometry
Point sources
Quasars
Red shift
Star mergers
Stars & galaxies
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Abstract We present a comprehensive analysis of 653 optical candidate counterparts reported during the third gravitational-wave (GW) observing run. Our sample concentrates on candidates from the 15 events (published in GWTC-2, GWTC-3, or not retracted on GraceDB) that had a >1% chance of including a neutron star in order to assess their viability as true kilonovae. In particular, we leverage tools available in real time, including pre-merger detections and cross-matching with catalogs (i.e., point-source, variable-star, quasar and host-galaxy redshift data sets), to eliminate 65% of candidates in our sample. We further employ spectroscopic classifications, late-time detections, and light-curve behavior analyses and conclude that 66 candidates remain viable kilonovae. These candidates lack sufficient information to determine their classifications, and the majority would require luminosities greater than that of AT 2017gfo. Pre-merger detections in public photometric survey data and comparison of cataloged host-galaxy redshifts with the GW event distances are critical to incorporate into vetting procedures, as these tools eliminated >20% and >30% of candidates, respectively. We expect that such tools that leverage archival information will significantly reduce the strain on spectroscopic and photometric follow-up resources in future observing runs. Finally, we discuss the critical role prompt updates from GW astronomers to the EM community play in reducing the number of candidates requiring vetting.
ISSN:0004-637X
1538-4357
1538-4357
DOI:10.3847/1538-4357/ac4d34