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GCN Circular 20708

Subject
LIGO/Virgo G274296: PESSTO classification of 9 Pan-STARRS transients
Date
2017-02-20T12:59:08Z (8 years ago)
From
S. J. Smartt at Queens U Belfast <s.smartt@qub.ac.uk>
F. Taddia, C. Barbarino, A. Nyholm, C. Fremling, J. Sollerman (OKC),
M. T. Botticella (INAF-Capodimonte), M. Fraser (UCD), C. Inserra,
E. Kankare, K. Maguire, S. J. Smartt, K. W. Smith, D. Wright, D. Young
(QUB), M. Sullivan (Southampton), S. Valenti (UC Davis), O. Yaron,
I. Manulis (Weizmann), E. Cappellaro (INAF-Padova), K. C. Chambers
(IfA), M. E. Huber (IfA), M. Coughlin (Harvard), T.-W. Chen (MPE),
L. Denneau, H. Flewelling, A. Heinze, T. Lowe, E. A. Magnier (IfA),
A. Rest (STScI), B. Stalder, A. S. B. Schultz (IfA), C. W. Stubbs
(Harvard) J. Tonry, C. Waters, R. J. Wainscoat, H. Weiland, M. Willman
(IfA)


PESSTO, the Public ESO Spectroscopic Survey for Transient Objects (see
Smartt et al. 2015, A&A, 579, 40 http://www.pessto.org), reports the
following supernova classifications related to G274296 within the cWB
map skyprobcc_cWB.fits (GCN 20689).

Targets were supplied by Pan-STARRS as in Chambers et al.
(GCN20699). For Pan-STARRS information, see Chambers et al. 2016
(arXiv:1612.05560, and http://pswww.ifa.hawaii.edu).  We selected
targets brighter than i=20.5 and accessible from La Silla.

All observations were performed on the ESO New Technology Telescope at
La Silla on 2017 February 19, using EFOSC2 and Grism 13 (3985-9315A,
18A resolution).  Classifications were done with SNID (Blondin &
Tonry, 2007, ApJ, 666, 1024) and GELATO (Harutyunyan et al., 2008,
A&A, 488, 383). Classification spectra and additional details can be
obtained from http://www.pessto.org (via WISeREP).

Name        RA (J2000)  Dec (J2000)  Disc. Date  Disc Mag   z      Type      Phase        Notes
PS17bcv     09 16 27.70 +03 35 25.2   20170218     19.9    0.104   IIn        ?                  (1)
PS17bda     09 30 36.08 +11 29 53.6   20170218     19.4    0.090   Ia         -3 to +3 d    (2) 
PS17bgx     09 20 37.01 +12 53 17.8   20170218     20.4    ?          ?          ?                  (3)
PS17bdt      10 17 28.88 +22 24 57.5   20170218     20.3    0.048   II         +12 d            (4)
PS17bdv     10 21 15.88 +23 38 53.2   20120218     20.4    0.14     Ia         +8 to +10 d  (5)
PS17bel      10 50 34.64 +30 25 30.7   20120218     20.0    0.116   Ia           +4 to +7 d   (6)
PS17beo     10 53 24.68 +28 51 27.1   20120218     19.6    0.217   IIn          +30 d          (7)
PS17bgn     11 31 52.98 +29 59 45.1   20120218     18.3    0.148   SLSN II   >+50d        (8)
PS17bek     10 47 41.90 +26 50 06.0   20120218     19.7    0          Stellar        -              (9)

Notes 

(1) Narrow Halpha and Hbeta in emission. Offset from the host-galaxy
center.

(2) Best SNID matches to several 1991T-like SNe Ia before and around
maximum. Redshift from SDSS.

(3)  Blue featureless spectrum. 

(4) Best SNID fit to SN 2004et at +12 d. Other good fits with SNe II
at +0 d and +20 d. Redshift from SDSS.

(5) Best SNID match with normal SN Ia 2002dj at +9 d. Several other
good matches with normal SNe Ia at similar age.

(6) Best SNID match with several normal SNe Ia at +4 to +7 d. Redshift
from SDSS.

(7) Good GELATO match to SN IIn 2010jl at +28 d. Absolute magnitude
-20.2 mag.

(8) Redshift and phase based on the best SNID match to SN IIL
1979C. Broad double-peaked Halpha and Hbeta, similar to 
nebular type II spectra.  Absolute magnitude -20.8 mag, very 
bright for inferred phase. 

(9) Narrow Halpha detection at z=0. Blue spectrum with black body
temperature of about 10000 K.
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