TITLE:   GCN CIRCULAR
NUMBER:  20509
SUBJECT: LIGO/Virgo G270580/GW170120 : Asiago observations
DATE:    17/01/23 13:09:13 GMT
FROM:    Andrea Rossi at INAF  <a.rossi@iasfbo.inaf.it>

P. Ochner, L. Tomasella (INAF-OAPd), A. Rossi, E. Palazzi 
(INAF-IASF Bo), E. Brocato (INAF-OAR), M. Branchesi 
(Urbino University/INFN Firenze), E. Cappellaro (INAF-OAPd), 
L.Amati (INAF-IASF Bo), L. A. Antonelli, (INAF-OAR), 
P. Astone (INFN-Roma), S. Benetti (INAF-OAPd), S. Campana, 
S. Covino, P. D'Avanzo, (INAF-OAB), V. D'Elia (INAF-ASDC), 
F. Getman (INAF-OAC), G. Giuffrida (INAF-ASDC), A.Grado 
(INAF-OAC), G.Greco (Urbino University/INFN Firenze), 
L. Limatola (INAF-OAC), M. Lisi (INAF-OAR), S. Marinoni, 
P. Marrese (INAF-ASDC), A. Melandri (INAF-OAB), 
L. Nicastro (INAF-IASF Bo), A. Pastorello (INAF-OAPd), 
E. Pian (SNS-Pisa), S. Piranomonte, L. Pulone (INAF-OAR), 
F. Ricci (Sapienza University), G. Stratta 
(Urbino University/INFN Firenze), G. Tagliaferri (INAF-OAB), 
V. Testa (INAF-OAR), on behalf of GRAWITA report:

The transients PTSS-17dfc (GCN 20497) and PTSS-17dgm (GCN 20506) were
observed with the Asiago 1.22m Galileo telescope (DFA-UniPd; equipped
with B&C spectrograph, range 330-790 nm, resolution 0.7 nm) and with
1.82m Copernico telescope (INAF-OAPd; equipped with AFOSC, range 340-820
nm, resolution 1.4 nm), respectively.

PTSS-17dfc was observed on 2017-01-22.901 UT and the best match is with
Type Ia SNe near  maximum light at a redshift ~0.022, which is
consistent with the spectroscopic redshift of the host galaxy provided
by SDSS-DR13 (z=0.024) .

PTSS-17dgm was observed on 2017-01-23.004 UT and the best match is also
with Type Ia SNe near maximum light at a redshift z~0.087,  consistent
with the photometric redshift provided by SDSS-DR13 (z=0.069).

The classifications were performed using the GELATO (Harutyunyan et al.
2008, A&A, 488, 383) and SNID (Blondin and Tonry 2007, ApJ, 666, 1024)
tools.

The classification as Type Ia SNe near maximum light
makes these events likely not related to LIGO/Virgo G270580.