[IAUC] CBET 2943: 20111215 : SUPERNOVA 2011iy IN NGC 4984 = PSN J13085839-1531041

Jue Dic 15 02:45:08 ART 2011

                                                  Electronic Telegram No. 2943
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 2011iy IN NGC 4984 = PSN J13085839-1531041
     Koichi Itagaki, Yamagata, Japan, reports his discovery of an apparent
supernova (mag 12.7) on an unfiltered CCD image (limiting mag 19.0) taken on
Dec. 9.856 UT with a 0.3-m f/8 reflector.  The new object is located at R.A.
= 13h08m58s.39, Decl. = -15d31'04".1 (equinox 2000.0), which is 16".6 east and
6".1 south of the nucleus of the presumed host galaxy, NGC 4984 (whose
position end figures were measured as 57s.24, 30'58".0).  The discovery image
is posted at website URL http://www.k-itagaki.jp/images/psn4984.jpg.  The
variable was designated PSN J13085839-1531041 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2011iy based on the
spectroscopic confirmations reported below.  Additional CCD magnitudes for
2011iy (unfiltered unless noted otherwise):  2007 Feb. 25.708, [19.5
(Itagaki); 2011 Dec. 10.541, 12.5 (Joseph Brimacombe, Cairns, Australia;
remotely using a 51-cm RCOS telescope + STL11K camera + luminance filter
at New Mexico Skies Observatory near Mayhill, NM, U.S.A.; position end
figures 58s.47, 04".6); 10.785, 12.8 (T. Noguchi, Katori, Chiba-ken, Japan;
0.23-m f/6.3 Schmidt-Cassegrain reflector + BITRAN BT-11E camera; limiting mag
15.5; position end figures 58s.38, 31'04".2; communicated via S. Nakano, Sumoto,
Japan).  Brimacombe's image of 2011iy is posted at the following website URL:
http://www.flickr.com/photos/43846774@N02/6492127541/.

     J. Chen and X.-F. Wang, Tsinghua Center for Astrophysics, Tsinghua
University; X.-L. Wang, 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 330-860 nm) of
PSN J13085839-1531041 = SN 2011iy that was obtained on 2011 Dec. 11.8 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 1-2 weeks after maximum
light.  The best fit to this spectrum found by GELATO (Harutyuyan et al. 2008,
A.Ap. 488, 383; available at URL https://gelato.tng.iac.es/login.cgi)
suggests that 2011iy is similar to SN 2002dj at 11 days after maximum light.
Adopting a recession velocity 1279 km/s for the host galaxy (NGC 4984), from
the NED, they measure the velocity of the Si II 635.5-nm absorption feature
to be about 13000 km/s, which is usually high for a type-Ia supernova at this
phase.

     M. Yamanaka and T. Ui, Hiroshima University; and A. Arai, Kyoto Sangyo
University, report that they obtained low-resolution optical spectra of PSN
J13085839-1531041 = SN 2011iy on Dec. 14.81 UT at the Higashi-Hiroshima
Observatory (resolution R = 400) of Hiroshima University, and at the Koyama
Astronomical Observatory (R = 600) of Kyoto Sangyo University.  The spectra
show the absorption line of Si II at 610 nm, Na I D at 580 nm, and the Ca II
infrared triplet at 820 nm -- whose lines velocities reach 11000, 10000, and
14000 km/s, respectively.  These profiles are similar to those of the type-Ia
supernova 2006X at 12 days after B-band maximum (Yamanaka et al. 2009, PASJ
61, 713).


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                         (C) Copyright 2011 CBAT
2011 December 15                 (CBET 2943)              Daniel W. E. Green