[IAUC] CBET 2940: 20111206 : SUPERNOVA 2011iv IN NGC 1404 = PSN J03385135-3535320

Mar Dic 6 02:28:39 ART 2011

                                                  Electronic Telegram No. 2940
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)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2011iv IN NGC 1404 = PSN J03385135-3535320
     Colin Drescher, Calamvale, Queensland, Australia, reports the discovery
by Stuart Parker (Oxford, Canterbury, New Zealand) of an apparent supernova
(red mag 12.8) on a 30-s unfiltered image taken on Dec. 2.570 UT using a
35-cm Celestron C14 f/6.3 Schmidt-Cassegrain reflector (+ ST10 CCD camera).
The new object is located at R.A. = 3h38m51s.35, Decl. = -35d35'32".0 (equinox
2000.0; measured by Drescher), which is 7" west and 8" north of the nucleus of
the galaxy NGC 1404.  The variable was designated PSN J03385135-3535320 when
it was posted at the Central Bureau's TOCP webpage and is here designated SN
2011iv based on the spectroscopic confirmation reported below.  Additional CCD
magnitudes for 2011iv:  Oct. 29.57, [18.8 (Parker); Dec. 4.693, 12.4 (Joseph
Brimacombe, Cairns, Australia; 41-cm RCOS telescope + STL6K camera + infrared
filter; bandpass > 700 nm; position end figures 51s.29, 31".7; image posted at
URL http://www.flickr.com/photos/43846774@N02/6456123621/); 4.508, 12.5 (T.
Noguchi, Katori, Chiba-ken, Japan; 0.23-m f/6.3 Schmidt-Cassegrain reflector
+ BITRAN BT-11E camera; limiting magnitude 16.5; position end figure 51s.35,
31".8; offset 7".6 west, 6".9 north; UCAC3 reference stars; communicated by
S. Nakano).

     J. Chen and X.-F. Wang, Tsinghua Center for Astrophysics, Tsinghua
University; W.-M. Yi, J.-J. Zhang, and J. M. Bai, Yunnan Astronomical
Observatory of China (YNAO); and T.-M. Zhang, National Astronomical
Observatories of China, report on an optical spectrogram (range 300-840 nm) of
PSN J03385135-3535320 = SN 2011iv that was obtained on Dec. 3.67 UT with the
2.4-m telescope (+ YFOSC) at the LiJiang Gaomeigu Station of YNAO.  The
spectrum is consistent with a type-Ia supernova at about a few days before
maximum light.  Adopting a recession velocity 1947 km/s for the host galaxy,
NGC 1404, from the NED, they measure the velocity of the Si II 635.5-nm
absorption feature to be about 11000 km/s.

     M. Stritzinger, Oskar Klien Center, Stockholm University; Nidia Morrell,
Las Campanas Observatory; and R. J. Foley, Harvard-Smithsonian Center for
Astrophysics, on behalf of the Millennium Center for Supernova Science, report
that they have obtained an optical spectrogram (wavelength range 359.0-965.7
nm) of PSN J03385135-3535320 = SN 2011iv on Dec. 4.1 UT with the Gemini South
telescope (+ GMOS).  The spectrum reveals that 2011iv is a type-Ia supernova
near maximum light.  Comparison with a library of supernova spectra (Blondin
and Tonry 2007, Ap.J. 666, 1024) suggests that 2011iv is similar to the normal
type-Ia supernovae 1992A and 2004eo at around 6 to 5 days before maximum.
Adopting a host-galaxy recession velocity of 1947 km/s (Graham et al. 1998,
A.Ap. Suppl. 113, 325) for the host galaxy (NGC 1404), Si II (635.5-nm) is
measured to be blue-shifted by roughly 11100 km/s.  NGC 1404 also hosted the
well-observed type-Ia supernova 2007on (CBETs 1121, 1131; Stritzinger et al.
2011, A.J. 142, 156).


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2011 CBAT
2011 December 6                  (CBET 2940)              Daniel W. E. Green