A Caltech Library Service

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

Anand, Shreya and Coughlin, Michael W. and Kasliwal, Mansi M. and Bulla, Mattia and Ahumada, Tomás and Sagués Carracedo, Ana and Almualla, Mouza and Andreoni, Igor and Stein, Robert and Foucart, François and Singer, Leo P. and Sollerman, Jesper and Bellm, Eric C. and Bolin, Bryce and Caballero-García, M. D. and Castro-Tirado, Alberto J. and Cenko, S. Bradley and De, Kishalay and Dekany, Richard G. and Duev, Dmitry A. and Feeney, Michael and Fremling, Christoffer and Goldstein, Daniel A. and Golkhou, V. Zach and Graham, Matthew J. and Guessoum, Nidhal and Hankins, Matthew J. and Hu, Youdong and Kong, Albert K. H. and Kool, Erik C. and Kulkarni, S. R. and Kumar, Harsh and Laher, Russ R. and Masci, Frank J. and Mróz, Przemek and Nissanke, Samaya and Porter, Michael and Reusch, Simeon and Riddle, Reed and Rosnet, Philippe and Rusholme, Ben and Serabyn, Eugene and Sánchez-Ramírez, R. and Rigault, Mickael and Shupe, David L. and Smith, Roger and Soumagnac, Maayane T. and Walters, Richard and Valeev, Azamat F. (2021) Optical follow-up of the neutron star–black hole mergers S200105ae and S200115j. Nature Astronomy, 5 (1). pp. 46-53. ISSN 2397-3366. doi:10.1038/s41550-020-1183-3.

[img] PDF - Submitted Version
See Usage Policy.

[img] PDF (Supplementary Figs. 1–4, Tables 1–3 and discussion) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Fig. 1: Limiting magnitudes at each epoch of observations) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Fig. 2: Automatic preliminary filtering criteria for transient detection) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Fig. 3: ZTF coverage and candidates discovered within skymap) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Fig. 4: Potential constraints on kilonova model parameters based on the deepest limiting magnitudes) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Fig. 5: Potential constraints on the parameters of a NSBH binary associated with S200105ae) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Fig. 6: Minimum aligned component of the BH spin above which we cannot rule out the presence of a kilonova) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Fig. 7: Potential constraints on the parameters of a NSBH binary associated with S190814bv) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Fig. 8: Broadband NSBH lightcurve models from POSSIS) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Fig. 9: Comparison of peak magnitudes between optical and near-IR bands for NSBH models) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


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 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, and independently measure the local expansion rate of the Universe. 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. 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⁻¹ 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.

Item Type:Article
Related URLs:
URLURL TypeDescription ReadCube access Paper
Anand, Shreya0000-0003-3768-7515
Coughlin, Michael W.0000-0002-8262-2924
Kasliwal, Mansi M.0000-0002-5619-4938
Bulla, Mattia0000-0002-8255-5127
Ahumada, Tomás0000-0002-2184-6430
Almualla, Mouza0000-0002-4694-7123
Andreoni, Igor0000-0002-8977-1498
Stein, Robert0000-0003-2434-0387
Foucart, François0000-0003-4617-4738
Singer, Leo P.0000-0001-9898-5597
Sollerman, Jesper0000-0003-1546-6615
Bellm, Eric C.0000-0001-8018-5348
Bolin, Bryce0000-0002-4950-6323
Caballero-García, M. D.0000-0001-7920-4564
Cenko, S. Bradley0000-0003-1673-970X
De, Kishalay0000-0002-8989-0542
Dekany, Richard G.0000-0002-5884-7867
Duev, Dmitry A.0000-0001-5060-8733
Fremling, Christoffer0000-0002-4223-103X
Goldstein, Daniel A.0000-0003-3461-8661
Golkhou, V. Zach0000-0001-8205-2506
Graham, Matthew J.0000-0002-3168-0139
Guessoum, Nidhal0000-0003-1585-8205
Hankins, Matthew J.0000-0001-9315-8437
Hu, Youdong0000-0002-7400-4608
Kong, Albert K. H.0000-0002-5105-344X
Kool, Erik C.0000-0002-7252-3877
Kulkarni, S. R.0000-0001-5390-8563
Laher, Russ R.0000-0003-2451-5482
Masci, Frank J.0000-0002-8532-9395
Mróz, Przemek0000-0001-7016-1692
Nissanke, Samaya0000-0001-6573-7773
Porter, Michael0000-0003-3168-5586
Riddle, Reed0000-0002-0387-370X
Rusholme, Ben0000-0001-7648-4142
Sánchez-Ramírez, R.0000-0002-7158-5099
Rigault, Mickael0000-0002-8121-2560
Shupe, David L.0000-0003-4401-0430
Smith, Roger0000-0001-7062-9726
Soumagnac, Maayane T.0000-0001-6753-1488
Walters, Richard0000-0002-1835-6078
Valeev, Azamat F.0000-0003-3513-3527
Additional Information:© 2020 Nature Publishing Group. Received 14 April 2020; Accepted 20 July 2020; Published 14 September 2020. This work was supported by the GROWTH (Global Relay of Observatories Watching Transients Happen) project funded by the National Science Foundation under PIRE grant no. 1545949. GROWTH is a collaborative project among California Institute of Technology (USA), University of Maryland College Park (USA), University of Wisconsin Milwaukee (USA), Texas Tech University (USA), San Diego State University (USA), University of Washington (USA), Los Alamos National Laboratory (USA), Tokyo Institute of Technology (Japan), National Central University (Taiwan), Indian Institute of Astrophysics (India), Indian Institute of Technology Bombay (India), Weizmann Institute of Science (Israel), The Oskar Klein Centre at Stockholm University (Sweden), Humboldt University (Germany), Liverpool John Moores University (UK) and University of Sydney (Australia). This work was based on observations obtained with the 48-inch Samuel Oschin Telescope and the 60-inch Telescope at the Palomar Observatory as part of the ZTF project. ZTF is supported by the National Science Foundation under grant no. AST-1440341 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington (UW), Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee and Lawrence Berkeley National Laboratories. Operations are conducted by Caltech Optical Observatories, IPAC, and UW. The work is partly based on the observations made with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, in the island of La Palma. The KPED team (M.W.C., R.G.D., D.A.D., M.F., S.R.K., E.S. and R.R.) thanks the National Science Foundation and the National Optical Astronomical Observatory for making the Kitt Peak 2.1-m telescope available. We thank the observatory staff at Kitt Peak for their efforts to assist Robo-AO KP operations. The KPED team thanks the National Science Foundation, the National Optical Astronomical Observatory, the Caltech Space Innovation Council and the Murty family for support in the building and operation of KPED. In addition, they thank the CHIMERA project for use of the Electron Multiplying CCD (EMCCD). SED Machine is based upon work supported by the National Science Foundation under grant no. 1106171 The ZTF forced-photometry service was funded under the Heising-Simons Foundation grant #12540303 (PI: Graham). M.W.C. acknowledges support from the National Science Foundation with grant no. PHY-2010970. S.A. gratefully acknowledges support from a GROWTH PIRE grant (1545949). Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. E.C.K. acknowledges support from the G.R.E.A.T. research environment and the Wenner-Gren Foundations. F.F. gratefully acknowledges support from NASA through grant 80NSSC18K0565, from the NSF through grant PHY-1806278, and from the DOE through CAREER grant DE-SC0020435. Data availability: The data that support the plots within this paper and other findings of this study are available from the corresponding authors on reasonable request. Code availability: The code (primarily in python) used to produce the figures is available from the corresponding authors on reasonable request. These authors contributed equally: Shreya Anand, Michael W. Coughlin. Author Contributions: S.A. and M.W.C. were the primary authors of the manuscript. M.M.K. is the PI of GROWTH and the ZTF EM-GW programme. M.B., A.S.C. and F.F. led the theory and modelling. T.A., M.A., N.G., I.A. and L.P.S. support the development of the GROWTH TOO Marshal and the associated programme. T.A., R. Stein, J.S., S.B.C., V.Z.G., A.K.H.K., H.K., E.C.K., P.M. and S.R. contributed to candidate scanning, vetting and classification. E.C.B. leads the ZTF scheduler and associated interfacing with the TOO programme. B.B. interpreted the asteroid candidates. M.D.C.-G., A.J.C.-T., Y.H., R. Sánchez-Ramírez and A.F.V. provided GTC data and associated analysis. K.D. and M.J.H. provided P200 follow-up. R.G.D., D.A.D., M.F., S.R.K., E.S. and R.R. provided KPED data. M.R. and R.W. provided SEDM data. C.F., M.J.G., R.R.L., F.J.M., P.M, M.P., P.R., B.R., D.L.S., R. Smith, M.T.S. and R.W. are ZTF builders. All authors contributed to editing the manuscript. The authors declare no competing interests. Peer review information: Nature Astronomy thanks Aaron Zimmerman and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Group:Infrared Processing and Analysis Center (IPAC), Astronomy Department, Zwicky Transient Facility
Funding AgencyGrant Number
ZTF partner institutionsUNSPECIFIED
Heising-Simons Foundation12540303
G.R.E.A.T. Research EnvironmentUNSPECIFIED
Wenner-Gren FoundationsUNSPECIFIED
Department of Energy (DOE)DE-SC0020435
Subject Keywords:Compact astrophysical objects; High-energy astrophysics; Time-domain astronomy
Issue or Number:1
Record Number:CaltechAUTHORS:20200717-162631605
Persistent URL:
Official Citation:Anand, S., Coughlin, M.W., Kasliwal, M.M. et al. Optical follow-up of the neutron star–black hole mergers S200105ae and S200115j. Nat Astron 5, 46–53 (2021).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104434
Deposited By: George Porter
Deposited On:24 Jul 2020 22:21
Last Modified:16 Nov 2021 18:31

Repository Staff Only: item control page