[IAUC] CBET 4010: 20141030 : SUPERNOVA 2014ds IN NGC 2536 = PSN J08111645+2510474

[quai en eps.harvard.edu]

                                                  Electronic Telegram No. 4010
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 2014ds IN NGC 2536 = PSN J08111645+2510474
     Z.-j. Xu (Nanjing, Jiangsu, China) and X. Gao (Urumqi, Xinjiang, China)
report the discovery of an apparent supernova (mag approximately 16.3) on one
40-s unfiltered CCD survey image (limiting mag about 18.0) taken by Gao in the
course of the Xingming Sky Survey around Oct. 11.939 UT using a 35.6-cm
Celestron C14 Schmidt-Cassegrain telescope at Mt. Nanshan.  The new object is
approximately located at R.A. = 8h11m16s.45, Decl. = +25d10'47".4 (equinox
2000.0), which is about 6".0 east and 1".7 north of the center of NGC 2536.
Nothing is visible at this position on archival images taken on Mar. 4
(limiting mag 18.5) and Mar. 31 (limiting mag 18.4) or on a Digitized Sky
Survey image from 1989 Jan. 10 (limiting mag about 19.9).  Images were posted
at website URL http://www.xjltp.com/XOSS/XM68ZX/XM68ZX.htm.  The variable was
designated PSN J08111645+2510474 when it was posted at the Central Bureau's
TOCP webpage and is here designated SN 2014ds based on the spectroscopic
confirmation reported below.  Additional CCD magnitudes for 2014ds:  2014
Oct. 12.376, 16.5 (J. Brimacombe, Cairns, Australia; remotely using a 51-cm
RCOS telescope + STXL-6303 camera at the New Mexico Skies observatory near
Mayhill, NM, U.S.A.; position end figures 16s.48, 46".7; image posted at
website URL https://www.flickr.com/photos/43846774@N02/15338033047/); 12.93,
16.1 (Xu and Gao; position end figures 16s.47, 47".3; image posted at URL
http://njzhijian.lamost.org/Supernova/PSNJ08111645+2510474-1012.jpg).

     J.-j. Zhang, Yunnan Astronimical Observatory (YNAO); and X.-f. Wang,
Tsinghua University, report on an optical spectrogram (range 360-890 nm) of
PSN J08111645+2510474 = SN 2014ds that was obtained on Oct. 23.8 UT with the
2.4-m telescope (+ YFOSC) at the LiJiang Gaomeigu Station of YNAO.  The
spectrum is consistent with a classification of type-IIb supernova, with Fe
II, Ca II, O I, and prominent H and He I features.  A more narrow H-alpha
emission is found to sit on top of the broad component, which is perhaps due
to the interaction of supernova ejecta with the circumstellar materials.
Cross-correlation with a library of supernova spectra using the comparison
tool "Gelato" (Harutyunyan et al. 2008, A.Ap. 488, 383) shows that 2014ds has
a good match with SN 2008ax at a few days before maximum light.  After
removing a recession velocity of 4142 km/s for the host galaxy, NGC 2536
(from de Vaucouleurs 1991, RC3.9), they measure a velocity of the H-alpha
absorption to be about 12600 km/s.


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

                         (C) Copyright 2014 CBAT
2014 October 30                  (CBET 4010)              Daniel W. E. Green