[IAUC] CBET 3282: 20121101 : SUPERNOVA 2012fw IN ESO 235-G37 = PSN J21015899-4816259

Jue Nov 1 08:26:12 ART 2012

                                                  Electronic Telegram No. 3282
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau en eps.harvard.edu (alternate cbat en iau.org)
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Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2012fw IN ESO 235-G37 = PSN J21015899-4816259
     A. Klotz, Institut de Recherche en Astrophysique et Planetologie, on
behalf of the TAROT Collaboration, reports the discovery of an apparent
supernova (mag about 15.3) on public images taken on Aug. 19.122 UT by the
0.25-m robotic telescope TAROT at the La Silla observatory, Chile.  The new
object is located approximately at R.A. = 21h01m58s.99, Decl. = -48o16'25".9
(equinox 2000.0), which is 7" west and 2" north of the nucleus of ESO 235-G37.
The variable was designated PSN J21015899-4816259 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2012fw based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2012fw:  Aug. 7.133, [18.6 (Klotz); 10.313, 16.5 (Klotz; pre-discovery);
23.517, 16.3 (Joseph Brimacombe, Cairns, Australia; infrared filter;
wavelength > 700 nm; position end figures 58s.97, 26".8; image posted at
website URL http://www.flickr.com/photos/43846774@N02/7848777388/).  Klotz
writes that spectroscopy of 2012fw was obtained by F. Colas (Institut de
Mecanique Celeste et de Calcul des Ephemerides, Paris) with A. Peyrot and
J. P. Teng (Association de Gestion de l'Observatoire Reunionnais
d'Astronomie, Les Makes, Reunion island), using the 60-cm telescope (+
grating filter with low dispersion of 4.8 nm/pixel) at Les Makes, Reunion
island on Aug. 21.6; comparison with spectra provided by C. Buil at URL
http://www.astrosurf.com/buil/supernovae/2011/index.htm suggests similarity
to the type-Ia supernova 2011fe at five days before maximum when redshifted
to z = 0.0186 (the redshift of the presumed host galaxy, ESO 235-G37),
with Si II lines being identified.  Additional information from Klotz was
posted at URL http://cador.obs-hp.fr/sn_tarot/PSN_J21015899-4816259/.

     L. Chomiuk and J. Strader, Michigan State University, report that a
spectrogram of PSN J21015899-4816259 = SN 2012fw, obtained on Aug. 22.1 UT
with the SOAR 4.1-m Telescope (+ GHTS; range 500-900 nm; resolution 1.1 nm)
is consistent with a normal type-Ia supernova.  Adopting for the host galaxy
(ESO 235-37) a redshift z = 0.0186 (Jones et al. 2009, MNRAS 399, 683; via
NED), a comparison with a library of supernova spectra via GELATO (Harutyuyan
et al. 2008, A.Ap. 488, 383) suggests that 2012fw is a few days before maximum.

     C. Inserra, S. J. Smartt, M. Fraser, D. Young, and K. Smith, Queen's
University, Belfast; F. Cellier-Holzem and P. El-Hage, Laboratoire de Physique
Nucleaire et de Hautes Energies, Paris; Y.-C. Pan, University of Oxford; M.
Sullivan, University of Southampton; I. Arcavi, A. Gal-Yam, and O. Yaron,
Wiezmann Institute of Science; S. Benetti, A. Pastorello, and S. Valenti,
Istituto Nazionale di Astrofisica, Padova; and S. Taubenberger, A. Sternberg,
and S. Benitez-Herrera, Max-Planck-Institute fuer Astrophysik, Garching, on
behalf of the PESSTO collaboration (see Valenti et al., posted at website URL
http://www.astronomerstelegram.org/?read=4037), report that optical
spectroscopy (range 360-910 nm), obtained on Aug. 26 with the New Technology
Telescope (+ EFOSC2), show that PSN J21015899-4816259 = SN 2012fw is a
type-Ia supernova at redshift z = 0.010; the best fit is to the spectrum of
SN 2002ck at maximum light, within a few days of the explosion.  PESSTO
classification spectra can be obtained at website URL http://www.pessto.org/;
classification is made via SNID (Blondin and Tonry 2007, Ap.J. 666, 1024) and
GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383).


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2012 CBAT
2012 November 1                  (CBET 3282)              Daniel W. E. Green