TITLE:   GCN CIRCULAR
NUMBER:  24359
SUBJECT: LIGO/Virgo S190426c: ZTF19aaslzjf, ZTF19aasmftm and ZTF19aasmddt 1.5m OSN and 10.4m GTC observations
DATE:    19/05/01 09:45:01 GMT
FROM:    Alberto J. Castro-Tirado at IAA-CSIC  <ajct@iaa.es>

Y.-D. Hu, A. J. Castro-Tirado, (IAA-CSIC), A. F. Valeev and V. V. 
Sokolov (SAO-RAS), R. Sanchez-Ramirez (INAF-IAPS), X.-Y. Li, A. Ayala, 
E. Fernandez-Garcia and F. J. Aceituno (IAA-CSIC), I. Carrasco, A. 
Castellon and C. Perez del Pulgar (UMA), M. D. Caballero-Garcia 
(ASU-CAS), S. B. Pandey (ARIES), A. Garcia and S. Geier (GRANTECAN, IAC, 
ULL), on behalf of a larger collaboration, report:

Following the detection of the three new transients ZTF19aaslzjf, 
ZTF19aasmftm and ZTF19aasmddt (Perley et al., GCN 24331) within the 
error area of the GW event S190426c (LVC, GCN 24237), we observed the 
three targets with the 1.5m telescope at the Observatorio de Sierra 
Nevada (Spain) in the BVI-bands, starting on May 1, 02:01 UT. In 
addition, optical spectra for each target (1200s) covering the range 
3700-7500 A were obtained with the 10.4m GTC telescope equipped with 
OSIRIS in La Palma (Spain) starting on May 1, 02:30 UT.

ZTF19aaslzjf is found to be in the outskirts of its host galaxy and its 
spectrum is consistent with that of a type Ia SN at z= 0.086.

ZTF19aasmftm is found to be in the outskirts of its host galaxy and its 
spectrum is consistent with that of a type Ia SN few days before maximum 
at z = 0.156 (confirmed by the emission lines of the galaxy).

ZTF19aasmddt is found to be in the outskirts of its host galaxy at a 
redshift z = 0.028. The spectrum resembles that of a Type II SN at the 
same redshift before maximum.

Therefore none of these three newly reported ZTF transients seem to be 
related to the GW event S190426c.

We acknowledge the excellent support from the GTC staff.