Follow-up Survey for the Binary Black Hole Merger GW200224_222234 Using Subaru/HSC and GTC/OSIRIS

Journal Article · Wed Apr 12 00:00:00 EDT 2023 · The Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/acbd42· OSTI ID:1991153

Ohgami, Takayuki  ^[1]; González, Josefa Becerra  ^[2]; Tominaga, Nozomu  ^[3]; Morokuma, Tomoki  ^[4]; Utsumi, Yousuke  ^[5]; Niino, Yuu  ^[6]; Tanaka, Masaomi  ^[7]; Banerjee, Smaranika  ^[7]; Poidevin, Frédérick  ^[2]; Acosta-Pulido, Jose Antonio  ^[2]; Pérez-Fournon, Ismael  ^[2]; Muñoz-Darias, Teo  ^[2]; Akitaya, Hiroshi  ^[8]; Yanagisawa, Kenshi  ^[9]; Sasada, Mahito  ^[9]; Yoshida, Michitoshi  ^[1]; Simunovic, Mirko  ^[1]; Ohsawa, Ryou  ^[10]; Tanaka, Ichi  ^[1]; Terai, Tsuyoshi  ^[1] ; Takagi, Yuhei  ^[1]

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1. National Astronomical Observatory of Japan (Japan)
2. Institute of Astrophysics of the Canary Islands (Spain); Univ. of La Laguna (Spain)
3. National Astronomical Observatory of Japan (Japan); Graduate University of Advanced Studies (Japan); Konan University (Japan); Univ. of Tokyo (Japan)
4. Chiba Institute of Technology (Japan); Univ. of Tokyo (Japan)
5. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Stanford Univ., CA (United States)
6. Univ. of Tokyo (Japan)
7. Tohoku Univ., Sendai (Japan)
8. Chiba Institute of Technology (Japan); Hiroshima Univ. (Japan)
9. Hiroshima Univ. (Japan); National Astronomical Observatory of Japan (Japan)
10. Univ. of Tokyo (Japan); National Astronomical Observatory of Japan (Japan)

The LIGO/Virgo detected a gravitational wave (GW) event, named GW200224_222234 (also known as S200224ca) and classified as a binary-black hole coalescence, on 2020 February 24. Given its relatively small localization skymap (71 deg² for a 90% credible region; revised to 50 deg² in GWTC-3), we performed target-of-opportunity observations using the Subaru/Hyper Suprime-Cam (HSC) in the r2 and z bands. Observations were conducted on 2020 February 25 and 28 and March 23, with the first epoch beginning 12.3 hr after the GW detection. The survey covered the highest-probability sky area of 56.6 deg², corresponding to a 91% probability. This was the first deep follow-up (m_r ≳ 24, m_z ≳ 23) for a binary-black hole merger covering >90% of the localization. By performing image subtraction and candidate screening including light-curve fitting with transient templates and examples, we found 22 off-nucleus transients that were not ruled out as the counterparts of GW200224_222234 with our Subaru/HSC data alone. We also performed GTC/OSIRIS spectroscopy of the probable host galaxies for five candidates; two are likely to be located within the 3D skymap, whereas the others are not. In conclusion, 19 transients remain as possible optical counterparts of GW200224_222234; but we could not identify a unique promising counterpart. If there are no counterparts in the remaining candidates, the upper limits of the optical luminosity are $$\nu {L}_{\nu }\lt {5.2}_{-1.9}^{+2.4}\times {10}^{41}$$ erg s^-1 and $$\nu {L}_{\nu }\lt {1.8}_{-0.6}^{+0.8}\times {10}^{42}$$ erg s^-1 in the r2 and z bands, respectively, at ~12 hr after GW detection. We also discuss improvements in the strategies of optical follow-ups for future GW events.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Contributing Organization: J-GEM Collaboration
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 1991153
• Journal Information: The Astrophysical Journal, Vol. 947, Issue 1; ISSN 0004-637X
• Publisher: IOP Publishing
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
black holes
gravitational waves
surveys