Electronic Telegram No. 4202
Central Bureau for Astronomical Telegrams
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SUPERNOVA 2015aw IN ESO 197-G24 = PSN J02062253-5201267
     Stuart Parker, Canterbury, New Zealand, reports the discovery of an
apparent supernova (red mag 15.9) on a 30-s unfiltered CCD image (limiting
mag 18.5) taken by himself on July 12.660 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. = 2h06m22s.53, Decl. = -52d01'26".7 (equinox J2000.0;
reference stars from USNO-B and UCAC4 catalogues), which is 16" east and 14"
north of the nucleus of the galaxy ESO 197-G24.  Nothing is visible at this
position on Digitized Sky Survey red and infrared images (limiting red mag
> 19).  Parker posted an image of the new variable that can be viewed via
website URL http://tinyurl.com/ntm4qhx.  The variable was designated PSN
J02062253-5201267 when it was posted at the Central Bureau's TOCP webpage
and is here designated SN 2015aw based on the spectroscopic confirmation
reported below.  J. Brimacombe, Cairns, Australia, reported mag 15.8 from
six images obtained on July 17.795, and he posted his images at website
URL https://www.flickr.com/photos/43846774@N02/19618887520/.

     N. Morrell, C. Contreras, and M. Phillips, Las Campanas Observatory; S.
Parker, Canterbury, New Zealand; and E. Y. Hsiao, Aarhus University, report
-- on behalf of the Carnegie Supernova Project -- that they obtained an
optical spectrogram (range 360-960 nm) of PSN J02062253-5201267 = SN 2015aw
on July 19.4 UT with the 2.5-m du Pont Telescope (+ WFCCD) at Las Campanas.
The spectrum shows a type-Ia supernova before maximum light.  Cross-
correlation with a library of supernova spectra via the "Supernova
Identification" tool (SNID; cf. Blondin and Tonry 2007, Ap.J. 666, 1024)
suggests that 2015aw is similar to many normal type-Ia supernovae around one
week before maximum brightness, although good matches are also found with
1991T-like events at a few days before maximum.  Adopting for the host galaxy
a recession velocity of 5882 km/s (Mathewson et al. 1992, Ap.J. Suppl. 81,
413; via NED), the minimum of the Si II 635.5-nm absorption is blueshifted
by 9800 km/s.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2015 CBAT
2015 November 24                 (CBET 4202)              Daniel W. E. Green