[IAUC] CBET 3545: 20130608 : SUPERNOVA 2013cx = PSN J17041605+4130376

Sab Jun 8 16:32:55 ART 2013

                                                  Electronic Telegram No. 3545
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 2013cx = PSN J17041605+4130376
     Xiaofeng Wang, Juncheng Chen, and Jide Liang, Tsinghua University (THU),
China; and Tianmeng Zhang, Lingzhi Wang, and Xu Zhou, National Astronomical
Observatories of China (NAOC), report the discovery of an apparent supernova
(mag 17.7) on unfiltered CCD images taken on May 21.71 UT using the 0.6-m
NAOC Schmidt telescope in the course of the THU-NAOC Transient Survey (TNTS).
The new object is located at R.A. = 17h04m16s.05, Decl. = +41d30'37".6 (equinox
2000.0), which is 1".3 east and 0".8 north of the center of the galaxy SDSS
J170415.96+413036.8.  Nothing is visible at this position on a Digitized Sky
Survey image.  The TNTS images are posted at the following website URL:
http://www.thca.tsinghua.edu.cn/~wangxf/TNTS/PSNJ17041606+4130373.png.  The
variable was designated PSN J17041605+4130376 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013cx based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2013cx:  Mar. 24, 20.0 (TNTS); May 29, 17.5 (TNTS);

     Xulin Zhao and Xiaofeng Wang, Tsinghua University (THU), China; and
Tianmeng Zhang, National Astronomical Observatories of China (NAOC), report on
an optical spectrogram (range 490-850 nm) of PSN J17041605+4130376 = 2013cx
that was obtained on May 31.70 UT with the 2.16-m telescope (+ BFOSC) at the
Xinglong Station of the NAOC.  The spectrum is consistent with a type-Ia
supernova at about one week after maximum light.  Cross-correlation with a
library of supernova spectra using the "Supernova Identification" code (SNID;
Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2013cx matches with SN
1995E at +9 days.  Adopting a redshift of 0.033 for the presumed host galaxy,
SDSS J170415.96+413036.8 (from narrow emission lines), they measure the
velocity of the Si II 635.5-nm absorption feature to be about 9900 km/s.

     L. Tomasella, S. Benetti, A. Pastorello, E. Cappellaro, P. Ochner, and M.
Turatto, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica,
report that an optical spectrogram (range 340-820 nm; resolution 1.3 nm), of
PSN J17041605+4130376 = SN 2013cx, obtained on June 7.01 UT with the Asiago
1.82-m Copernico Telescope (+ AFOSC), shows that this is a type-Ia supernova
at redshift z about 0.036.  A good match is found with several normal type-Ia
supernovae at about twelve days after maximum light.  The expansion velocity,
deduced from the Si II 635.5-nm absorption, is about 9900 km/s.  The Asiago
classification spectra are posted at website URL http://graspa.oapd.inaf.it;
classification was made via GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383)
and SNID (Blondin and Tonry 2007, Ap.J. 666, 1024).

     R. Lunnan, M. R. Drout, and E. Berger, Harvard University, obtained a
low-resolution spectum of PSN J17041605+4130376 = SN 2013cx on June 7.44 UT
with the Blue Channel spectrograph mounted on 6.5-m MMT at Mount Hopkins.
Comparison with a library of supernova spectra using the "Supernova
Identification" tool (SNID; Blondin and Tonry 2007, Ap.J. 1024, 666) provides
a good match with type-Ia supernovae at two weeks after maximum light.  They
measure the redshift of the host galaxy to be 0.034 from narrow emission
lines in the spectrum.


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                         (C) Copyright 2013 CBAT
2013 June 8                      (CBET 3545)              Daniel W. E. Green