TITLE:   GCN CIRCULAR
NUMBER:  24208
SUBJECT: LIGO/Virgo S190425z: GRAWITA TNG observations of ZTF19aarzaod
DATE:    19/04/26 03:58:37 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

L. Izzo (IAA/CSIC), R. Carini (INAF-OAR),  S. Benetti (INAF-OAPd), S. Piranomonte (INAF-OAR), P. D'Avanzo, A. Melandri  (INAF-OAB), M.T. Botticella (INAF-OAC), 
V. D'Elia (ASI-SSDC), V. Testa (INAF-OAR), G. Greco (Urbino Univ.), S. Yang (INAF-OAPd), E. Brocato (INAF-OAAb, INAF-OAR), A. Harutyunyan, C. Padilla Torres (INAF-TNG) 
on behalf of GRAWITA report:

 
We observed ZTF19aarzaod, one of the two most promising counterpart candidates reported by the Zwicky Transient Facility (Kasliwal et al., GCN 24191) for the GW event S190425z (GCN 24168),  
with the 3.6m Italian TNG telescope (Canary Islands, Spain), equipped with the DOLORES camera in spectroscopic mode starting on 2019-04-26 at 01:47:38 UT. An optical spectrum, lasting 2700 s, 
was obtained using the grism LR-B (wavelength range ~ 400-800 nm). 
The spectrum shows a red continuum with a broad emission consistent with being Halpha at the redshift of the host galaxy (z=0.028; Kasliwal et al., GCN 24191). Our results are consistent with the 
findings reported by Buckley et al. (GCN 24205) and suggest that ZTF19aarzaod is not related to the GW event S190425z. 


We thank the TNG visitor E. Knudstrup.