Optical follow-up of the neutron star-black hole mergers S200105ae and S200115j

DOI: 
10.1038/s41550-020-1183-3
Publication date: 
01/01/2021
Main author: 
Anand, Shreya
IAA authors: 
Castro-Tirado, Alberto J.;Hu, Youdong
Authors: 
Anand, Shreya;Coughlin, Michael W.;Kasliwal, Mansi M.;Bulla, Mattia;Ahumada, Tomás;Sagués Carracedo, Ana;Almualla, Mouza;Andreoni, Igor;Stein, Robert;Foucart, Francois;Singer, Leo P.;Sollerman, Jesper;Bellm, Eric C.;Bolin, Bryce;Caballero-García, M. D.;Castro-Tirado, Alberto J.;Cenko, S. Bradley;De, Kishalay;Dekany, Richard G.;Duev, Dmitry A.;Feeney, Michael;Fremling, Christoffer;Goldstein, Daniel A.;Golkhou, V. Zach;Graham, Matthew J.;Guessoum, Nidhal;Hankins, Matthew J.;Hu, Youdong;Kong, Albert K. H.;Kool, Erik C.;Kulkarni, S. R.;Kumar, Harsh;Laher, Russ R.;Masci, Frank J.;Mróz, Przemek;Nissanke, Samaya;Porter, Michael;Reusch, Simeon;Riddle, Reed;Rosnet, Philippe;Rusholme, Ben;Serabyn, Eugene;Sánchez-Ramírez, R.;Rigault, Mickael;Shupe, David L.;Smith, Roger;Soumagnac, Maayane T.;Walters, Richard;Valeev, Azamat F.
Journal: 
Nature Astronomy
Refereed: 
Yes
Publication type: 
Article
Volume: 
5
Pages: 
46–53
Abstract: 
LIGO and Virgo's third observing run revealed the first neutron star-black hole (NSBH) merger candidates in gravitational waves. These events are predicted to synthesize r-process elements<SUP>1,2</SUP> creating optical/near-infrared `kilonova' emission. The joint gravitational wave and electromagnetic detection of an NSBH merger could be used to constrain the equation of state of dense nuclear matter<SUP>3</SUP>, and independently measure the local expansion rate of the Universe<SUP>4</SUP>. Here, we present the optical follow-up and analysis of two of the only three high-significance NSBH merger candidates detected to date, S200105ae and S200115j, with the Zwicky Transient Facility<SUP>5</SUP>. The Zwicky Transient Facility observed ~48% of S200105ae and ~22% of S200115j's localization probabilities, with observations sensitive to kilonovae brighter than -17.5 mag fading at 0.5 mag d<SUP>-1</SUP> in the g- and r-bands; extensive searches and systematic follow-up of candidates did not yield a viable counterpart. We present state-of-the-art kilonova models tailored to NSBH systems that place constraints on the ejecta properties of these NSBH mergers. We show that with observed depths of apparent magnitude ~22 mag, attainable in metre-class, wide-field-of-view survey instruments, strong constraints on ejecta mass are possible, with the potential to rule out low mass ratios, high black hole spins and large neutron star radii.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2020NatAs.tmp..179A/abstract
ADS Bibcode: 
2020NatAs.tmp..179A
Keywords: 
Astrophysics - High Energy Astrophysical Phenomena;General Relativity and Quantum Cosmology