Supernova 2014ef in NGC 309 = Psn J00563965-0954028
Abstract
S. Nakano, Sumoto, Japan, reports the discovery by K. Itagaki (Teppo-cho, Yamagata, Japan) of an apparent supernova (mag 17.9) in NGC 309 on an unfiltered CCD frame (limiting mag 19.5) taken on 2014 Dec. 13.519 UT using a 0.50-m f/6.8 reflector remotely at the Takanezawa station, Tochigi-ken. The new object is located at R.A. = 0h56m39s.65, Decl. = -9d54'02".8 (equinox 2000.0; reference stars from UCAC4 catalogue), which is 44".3 west and 47".0 north of the nucleus of NGC 309 (position end figures 42s.65, 49".8). Itagaki posted his discovery image at website URL http://k-itagaki.jp/images/309.jpg. The variable was designated PSN J00563965-0954028 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2014ef based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2014ef: 2006 Aug. 30.654, [19.0 (Itagaki, 0.60-m f/5.7 reflector at Yamagata); 2014 Nov. 22.489, [18.5 (Itagaki); Dec. 13.585, 18.2 (T. Noguchi, Katori, Chiba-ken, Japan; 0.23-m f/6.3 Schmidt-Cassegrain reflector + FLI ML0261E camera; position end figures 39s.67, 03".3; image posted at website URL http://park8.wakwak.com/~ngc/images/PSNinNGC309.jpg; communicated by Nakano); 14.432, V = 17.74, I_c = 17.40 (S. Kiyota, Kamagaya, Japan; remotely with an iTelescope 0.5-m CDK astrograph + FLI PL-9000 CCD camera at Siding Spring); 14.468, 17.9 (T. Yusa and N. Wada, Osaki, Japan; 0.30-m reflector; position end figures 39s.63, 02".6; limiting mag 18.5; image posted at website URL http://space.geocities.jp/yusastar77/supernova/PSNinNGC309_141214.htm); 17.888, 18.0 (G. Masi and P. Catalano; remotely using a 43-cm telescope at Ceccano, Italy; position end figures 39s.65, 03".6); 18.521, 17.9 (F. Watanabe, Nayoro, Japan; 0.50-m f/9.5 reflector + SBIG STL-1001E camera; position end figures 39s.68, 02".5); 20.154, 17.9 (A. Valvasori and F. Briganti; remotely using the iTelescope T21 Dall-Kirkham 43.1-cm f/4.5 reflector near Mayhill, NM, U.S.A.). Y. Cao, California Institute of Technology; M. Kasliwal, Carnegie Institution for Science, Pasadena, and Princeton University; Y. AlSayyad, University of Washington; and S. R. Kulkarni, California Institute of Technology, report spectroscopic classification of PSN J00563965-0954028 = SN 2014ef with the Dual Imaging Spectrograph mounted on the ARC 3.5-m telescope at the Apache Point Observatory on 2014 Dec. 16 UT. The Superfit software (Howell et al. 2005, Ap.J. 634, 1190) finds that the spectrum of 2014ef matches that of the type-Ib/c supernova 1999ex a few days after peak, thus determining the redshift of 2014ef to be 0.02. At this redshift, they see no hydrogen line in the spectrum but identify He I 587.6-, 667.8-, and 706.5-nm with their minima at an expansion velocity of 6000 km/s. Therefore, they classify 2014ef as a type-Ib supernova at redshift 0.02.
- Publication:
-
Central Bureau Electronic Telegrams
- Pub Date:
- January 2015
- Bibcode:
- 2015CBET.4059....1N