[vsnet-grb-info 24976] LIGO/Virgo S200213t: P200 Spectroscopy of ZTF20aanakcd/AT2020cmr

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27075
SUBJECT: LIGO/Virgo S200213t: P200 Spectroscopy of ZTF20aanakcd/AT2020cmr
DATE:    20/02/15 06:23:56 GMT
FROM:    Igor Andreoni at Caltech  <igor.andreoni at gmail.com>

Igor Andreoni (Caltech), Kishalay De (Caltech), Mansi Kasliwal (Caltech), Yang Huang (Yunnan Univ.), Xiaowei Liu (Yunnan Univ.)
On behalf of the GROWTH collaboration

On 2020-02-15 03:30 UT, we used the Double Beam Spectrograph (Oke & Gunn 1982) on the Palomar 200-inch telescope to observe ZTF20aanakcd/AT2020cmr (Reusch et al., GCN #27068), a transient discovered with the Zwicky Transient Facility (Graham et al., 2019; Bellm et al., 2019) during the follow-up of the binary neutron star merger candidate S200213t (LVC, GCN #2704).

The optical spectrum shows intermediate width Balmer emission features consistent with a Type IIn supernova at z=0.077. We also confirmed that the redshift of the transient is consistent with the host galaxy redshift, extracted from the same observations, based on the analysis of Balmer and [S II] lines.  We conclude that ZTF20aanakcd/AT2020cmr is unrelated to S200213t.