Multi-Messenger Astronomy with Subaru II Myungshin Im (Seoul National University) 2019-01-16 EAO-Subaru Science Workshop@KASI

GW170817: NS-NS merger Multi-Messenger Astronomy 2017-08-17 GW event marked the start of MMA using GW and EMW signals 3700 (39@Korea, 45 countries, 900+ institutions, 80 facilities ), 59 page ApJL paper

Facilities for EM Follow-up: 17+ telescopes Korea: SAO 1.0m/0.6m, SOAO 0.6m, BOAO 1.8m, DOAO 1.0m Maidanak: 1.5m Telescope US: LOAO 1-m Gemini-N UKIRT Gemini-S US: McDonald 2.1-m, 0.8m, 0.25m KMTNet 1.6m Telescopes Australia: 0.43m LSGT + iTelescope.Net (SSO)

First Korean Observation At 2017-8-18, about 21 hours after the GW detection, the GW EM counterpart was detected by LSGT (0.43m telescope!) Optical counterpart of GW170817 taken with LSGT GW170817 NGC 4993 서울대학교 초기우주천체연구단 2017-08-18 10:08:01(UT) 서울대학교 초기우주천체연구단 Lee Sang Gak Telescope (LSGT@SSO) Im et al. 2017, 2019, Abbott et al. 2017

KMTNet Image of GW170817 서울대학교/한국천문연구원 KMTNet-SAAO 08-18 Troja et al. 2017, Im et al. 2017, Abbott et al. 2017

Several key results Binary neutron star merger  short GRB-like event? YES EM counterpart = Kilonova? YES - blue or red? Both - Brightness? 17 mag in the beginning Environment of NS merger? Massive elliptical galaxy Gold! (200 ME) H0 from GW

Upcoming Challenges More events at further distances: Faint counterparts BH-BH merger: any EM counterpart BH-NS/BNS merger: general characteristics Credit: A. Simonnet

Event rate & localization area BNS ~ 13/yr BBH ~ 100/yr NS-BH ~ 1/10 of BNS Abbott et al. (2016) Localization: 5 – 20 deg2

Light curve prediction Tanaka et al. (2017) EM counterpart: Faint (23 – 24 mag): neutrino source too! How can we identify them? Wide-field, deep image [Pan-STARRS depths: grizy = 23.3, 23.2 23.1, 22.3, 21.3]

Multi-Messenger Astronomy with Subaru Subaru Hemisphere Survey Hemisphere wide-field imaging 2 * π ~ 20,000 deg2 3 min (1 min x 3)  r= 25.4 mag (5-σ) 1 night (8 hr)  216 deg2 130 nights (incl. weather loss 30%)  21,600 deg2 Subaru Hemisphere Survey (SHS) LSST

Subaru Hemisphere Survey Science Faint transient - GW, GRB, Neutrino counterparts - Supernovae, novae, …. Solar system object Galaxy evolution Cosmology (cluster identification), etc Long-lasting archive for the whole world

SHS + Transient follow-up Combination of SHS + another transient follow-up survey (Subaru, Gemini, KMTNet, etc)  GW source EM identification + many other projects possible (more targets for PFS) A great way of EAO collaboration?