TITLE:   GCN CIRCULAR
NUMBER:  20524
SUBJECT: LIGO/Virgo G270580: Asiago 1.82m observations of PS17ua and PS17yt
DATE:    17/01/25 11:03:02 GMT
FROM:    Andrea Melandri at INAF-OAB  <andy.melandri@gmail.com>

L. Tomasella, E. Cappellaro, A. Pastorello, S.Yang (INAF-OAPd), L. Amati (INAF-IASF Bo), L. A. Antonelli, (INAF-OAR), S. Ascenzi (INAF-OAR), M. T. Botticella (INAF-OAC),  M. Branchesi (Urbino University/INFN Firenze), S. Campana (INAF-OAB), S. Covino, P. D'Avanzo (INAF-OAB), V. D'Elia (INAF-ASDC), F. Getman (INAF-OAC), A. Grado (INAF-OAC), G. Greco (Urbino University/INFN Firenze), L. Limatola (INAF-OAC), M. Lisi (INAF-OAR), A. Melandri (INAF-OAB), L. Nicastro (INAF-IASF Bo), E. Palazzi (INAF-IASF Bo), E. Pian (SNS-Pisa), S. Piranomonte (INAF-OAR), L. Pulone (INAF-OAR), A. Rossi (INAF-IASF Bo), G. Stratta (Urbino University/INFN Firenze), G. Tagliaferri (INAF-OAB), V. Testa (INAF-OAR), E. Brocato (INAF-OAR) on behalf of GRavitational Wave Inaf TeAm report:


The transients PS17ua (Huber et al., LVC GCN 20518) and PS17yt (Chambers et al., LVC GCN 20512) were observed with 1.82m Copernico telescope (INAF-OAPd; equipped with AFOSC, range 340-820nm, resolution 1.4 nm).

PS17ua was observed in spectroscopic mode for 2400 sec, starting at 2017-01-24.920 UT.

The spectrum shows that this transient is a Type Ia SN, about one week before maximum light, at a redshift ~0.051, which is consistent with the photometric redshift of the host galaxy provided by SDSS-DR13 (photoZ (KD-tree method)=0.067+/-0.017 and photoZ (RF method)=0.059+/-0.021).

We also measured for PS17ua the following Sloan AB magnitudes: g=17.67, r=17.61, i=18.15 +/-0.01. The classification was performed using the GELATO (Harutyunyan et al. 2008, A&A, 488, 383) and SNID (Blondin and Tonry 2007, ApJ, 666, 1024) tools.

PS17yt was observed in photometric mode in the ugriz bands on 2017-01-24.982 UT, measuring the following Sloan AB magnitudes: g=18.881+/-0.015, r=19.022+/-0.017, i=19.179+/-0.031, z=19.46+/-0.07, u=19.54+/-0.04. We also measured the following Vega magnitudes: B-Bessell=18.92+/-0.02, V-Bessell=18.94+/-0.03.