[vsnet-grb-info 24492] LIGO/Virgo S191213g: AT2019wxt 10.4m GTC further spectroscopy

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26591
SUBJECT: LIGO/Virgo S191213g: AT2019wxt 10.4m GTC further spectroscopy
DATE:    19/12/26 09:37:08 GMT
FROM:    Alberto J. Castro-Tirado at IAA-CSIC  <ajct at iaa.es>

A. F. Valeev (SAO-RAS), A. J. Castro-Tirado, Y.-D. Hu and E. 
Fernandez-Garcia (IAA-CSIC), V. Sokolov (SAO-RAS), I. Carrasco and A. 
Castellon (UMA), S. B. Pandey (ARIES) and N. Castro-Rodriguez 
(GRANTECAN, IAC, ULL), on behalf of a larger collaboration, report:

McBrien et al. (GCN 26485) reported the intrinsically faint optical 
transient PS19hgw (AT2019wxt) in the 80% probability contour of the 
compact binary merger event S191213g (LVC, GCN 26402) and spectroscopic 
observations were conducted by Izzo et al. (GCN 26491), Srivastav and 
Smartt (GCN 26493), Muller Bravo et al. (GCN 26494), Vogl et al. (GCN 
26504), Dutta et al. (GCN 26490), Vallely et al. (GCN 26508 ) and 
Becerra-Gonzalez et al (GCN 26521).

We performed a first epoch of spectroscopic observations on Dec 18, 21 
UT with the 10.4m GTC telescope (+ OSIRIS) in La Palma (Spain) covering 
the range 3,700-10,000 A showing a blue continuum with broad shallow He 
I lines. Following the report by Hubber et al. of a rapid optical decay 
(GCNC 26577) a second epoch spectrum was obtained on Dec 24, 20 UT with 
GTC and the same set-up. The 2nd epoch spectrum shows broad features at 
~4,500 A and ~5,900A (rest frame) resembling pretty much those of the 
SN2011fu (a type IIb SN) at about 25 days. Therefore, it seems certain 
the classification of AT2019wxt as a type IIb SN. See 
http://jet.sao.ru/~azamat/GW/PS19hgw2019-12-24T19:50.jpeg .

This work can be quoted.