[IAUC] CBET 3791: 20140120 : SUPERNOVA 2014I IN PGC 17633 = PSN J05421980-2532399

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                                                  Electronic Telegram No. 3791
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 2014I IN PGC 17633 = PSN J05421980-2532399
     [Editor's note:  this replaces the text on CBET 3790 (designation).]
     Stuart Parker, Canterbury, New Zealand, reports the discovery of an
apparent supernova (red mag 17.0) on a 30-s unfiltered CCD image (limiting mag
19) taken by himself on Jan. 17.520 UT with a 30-cm Astro-Tech AT12RC
Ritchey-Chretien astrograph (+ ST10 camera) at his Parkdale Observatory in the
course of the Backyard Observatory Supernova Search.  The new object is
located at R.A. = 5h42m19s.80, Decl. = -25d32'39".9 (equinox 2000.0; reference
stars from USNO-B and UCAC4 catalogues), which is 15" west and 12" south of
the nucleus of the galaxy PGC 17633 = ESO 487-G36.  Nothing is visible at this
position on Digitized Sky Survey red and infrared images (limiting red mag >
19).  An image of the variable is visible via URL http://tinyurl.com/kl4a876.
The variable was designated PSN J05421980-2532399 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2014I based on the
spectroscopic confirmation reported below.

     M. Childress, R. Scalzo, F. Yuan, and B. Schmidt, Australian National
University (ANU); and B. Tucker, ANU and University of California at Berkeley,
report spectroscopic classification of PSN J05421980-2532399 = SN 2014I with
the Wide Field Spectrograph (cf. Dopita et al. 2007, Ap. Space Sci. 310, 255)
on the ANU 2.3-m telescope at Siding Spring using the B3000/R3000 gratings
(wavelength range 350-980 nm at 0.1-nm resolution).  An 80-min spectrogram
taken on Jan 18.56 UT shows 2014I to be a type-Ia supernova a few days before
maximum light.  Typical type-Ia features are present, such as Si 635.5-nm, Ca
H/K and the infrared triplet, the sulfur "W" feature, and Fe complexes in the
region 400-500 nm.  Classification with SNID (Blondin and Tonry 2007, Ap.J.
666, 1024) shows good matches to type-Ia supernovae a few days before maximum
light (with the best match to SN 1996ai at -1 days) at a redshift of around
z = 0.031, consistent with redshift of the apparent host galaxy, PGC 17633 (=
ESO 487-G36; z = 0.03001, via Wegner et al. 1999, MNRAS 305, 259).  Adopting
the redshift of the apparent host galaxy, they measure a Si 635.5-nm
absorption minimum at 11000 km/s, as well as apparent high-velocity features
in the Ca infrared triplet at 20000 km/s (see Childress et al. 2014, MNRAS
437, 338).


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2014 CBAT
2014 January 20                  (CBET 3791)              Daniel W. E. Green