[IAUC] CBET 2776: 20110803 : SUPERNOVA 2011eh IN NGC 3613 = PSN J11183170+5758372

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                                                  Electronic Telegram No. 2776
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 2011eh IN NGC 3613 = PSN J11183170+5758372
     S. Nakano, Sumoto, Japan, reports the discovery by Masaki Tsuboi
(Kuchita-minami, Asakita-ku, Hiroshima, Japan) of an apparent supernova (mag
16.2) on a 30-s unfiltered CCD frame taken on July 20.48 UT using a 0.30-m
f/5.3 reflector (+ ST-2000XM camera); Tsuboi confirmed the object on two
frames taken two hours later using the same instrument (limiting magnitude
17.5).  The new object was measured by Tsuboi to be located at R.A. =
11h18m31s.7, Decl. = +57d58'37".2 (equinox 2000.0), or 35".5 west and 83".0
south of the center of NGC 3613.  The variable was designated as PSN
J11183170+5758372 when posted at the Central Bureau's TOCP webpage and is
here designated SN 2011eh based on the spectroscopic report below.  Tsuboi
adds that nothing is visible at the position of 2011eh on two frames taken on
2011 May 19.599 and June 3.577 using the same instrument, and that nothing is
visible to limiting red mag 19 or fainter on Digitized Sky Survey images.
The discovery image was posted at the following website URL:
http://www42.tok2.com/home/hiroten/astrophoto/NGC3613110720-01.jpg.
     Additional magnitudes for 2011eh:  July 17.527 UT, 17.5 (Koichi Itagaki,
Yamagata, Japan; 0.60-m f/5.7 reflector + unfiltered CCD; pre-discovery;
communicated by Nakano; position end figures 31s.47, 36".5); 21.487, 16.0
(Toshihide Noguchi, Katori, Chiba-ken; 0.23-m Schmidt-Cassegrain reflector
+ unfiltered BITRAN BT-11E CCD camera; limiting mag 17.5; position end
figures 31s.54, 36".9; communicated by Nakano); 21.533, 15.8 (Tsuboi);
23.160, 14.3 (T. Yusa, Osaki, Japan; remotely using a 0.25-m f/3.4 hyperbolic
astrograph + unfiltered SBIG ST-10XME CCD camera at the RAS Observatory near
Mayhill, NM, U.S.A.; position end figures 31s.56, 37".2; offset 36" west, 83"
south; limiting mag 18.5; image posted at the following website URL:
http://www.palette.furukawa.miyagi.jp/space/images/PSNinNGC3613_110723.jpg);
23.202, 15.0 (Joseph Brimacombe, Cairns, Australia; image posted at URL
http://www.flickr.com/photos/43846774@N02/5973968188/); 25.228, 14.7
(Brimacombe; image at http://www.flickr.com/photos/43846774@N02/5975900657/);
26.182, 14.6 (Brimacombe); 29.919, 14.7 (Federica Luppi, 0.36-m f/7.9 reflector
+ Bessell R filter; position end figures 31s.55, 36".8; image posted at URL
http://www.astrogeo.va.it/pub/TOCP/PSN_N3613.jpg); 30.923, 14.8 (Xavier Bros,
Ager, Catalonia, Spain; 35-cm f/4.6 telescope + unfiltered ST8-XME CCD camera).

     M. Yamanaka and R. Itoh, Hiroshima University, report that they obtained
a low-resolution optical spectrum (R = 400) of PSN J11183170+5758372 = SN
2011eh on July 30.6 UT at the Higashi-Hiroshima Observatory of Hiroshima
University.  The spectrum shows the absorption line of Si II at 620 nm, O I
at 750 nm, and the Ca II infrared triplet at 820 nm, whose lines velocities
reach 10000, 14000, and 14000 km/s, respectively.  The spectrum also exhibits
Si II absorption lines around 580 nm.  The intensity ratio of Si II absorption
lines at 580 nm to 610 nm is comparable of that seen for SN 1991bg.  These
profiles are similar to those of the subluminous type-Ia supernova 1991bg
at maximum.


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

                         (C) Copyright 2011 CBAT
2011 August 3                    (CBET 2776)              Daniel W. E. Green



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