[IAUC] CBET 4203: 20151124 : SUPERNOVA 2015ax = PSN J01181560+1505588

Mar Nov 24 16:50:40 ART 2015

                                                  Electronic Telegram No. 4203
Central Bureau for Astronomical Telegrams
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SUPERNOVA 2015ax = PSN J01181560+1505588
     Francois Kugel, Dauban, Banon, France, reports his discovery of an
apparent supernova (red mag 17.2) on CCD exposures obtained of comet C/2014
A4 by A. Klotz and himself with a 0.20-m f/4 Schmidt-Cassegrain reflector (+
Sloan r' filter) on Oct. 30.827 UT.  The new object was measured to have
position R.A. = 1h18m15s.60, Decl. = +15d05'58".8 (equinox J2000.0; reference
stars from USNO-SA2.0 catalogue), which is 12" east and 2" north of the center
of the galaxy 2MFGC 973 in p.a. 78 deg.  Nothing is visible at this position
on a red Digitized Sky Survey image of the galaxy.  Kugel posted his image at
URL http://fkometes.pagesperso-orange.fr/images/SN_/possSN20151030.jpg.
The variable was designated PSN J01181560+1505588 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2015ax based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2015ax:  Oct. 31.524, 17.2 (Kugel; measured from an image taken by A. Klotz,
D. Turpin, D. Coward, and J. Moore with the 100-cm Zadko robotic telescope
+ "J" filter at Gingin, Australia); 31.766, 17.3 (Kugel; position end figures
15s.54, 59.5); 31.96, 17.7 (P. Dupouy and J.-B. de Vanssay, Dax, France;
0.43-m f/2.7 reflector; position end figures 15s.58, 58".5); Nov. 1.129, 17.3
(A. Maury and J.-F. Soulier; 0.4-m f/8 Ritchey-Chretien reflector at San
Pedro de Atacama, Chile; position end figures 15s.56, 58".1; image posted at
website URL http://6888comete.free.fr/images/forum/SnK1101A.jpg); 1.883, 17.5
(J. Nicolas, Dauban, France; 0.41-m f/3.3 reflector); 1.936, 17.4 (J.-F.
Soulier, Maisoncelles, France; 0.30-m f/3.8 Newtonian reflector; position end
figures 15s.57, 58".5; UCAC-4 reference stars; image posted at website URL
http://6888comete.free.fr/images/forum/SnK1101B.jpg); 2.847, 18.0 (G. Masi;
remotely using a 43-cm telescope at Ceccano, Italy; position end figures
15s.58, 58".2); 4.862, 17.5 (Nicolas).

     Liming Rui and Xiaofeng Wang, Tsinghua University; and Tianmeng Zhang,
National Astronomical Observatories of China (NAOC), report on an optical
spectrogram of PSN J01181560+1505588 = SN 2015ax was obtained on Nov. 3.9 UT
with the 2.16-m telescope (+ BFOSC) at the Xinglong Station of the NAOC.  The
spectrum is consistent with a type-Ia supernova a few days after maximum
light.  Cross-correlation with a library of supernova spectra using the
comparison tool SNID (Blondin and Tonry 2007, Ap.J. 666, 1024) shows that
2015ax matches with SN 2002fk at +4 days.  Adopting a redshift of 0.054 for
its host galaxy, FGC 146 (Haynes et al. 2011, A.J. 142, 170), an expansion
velocity of about 9300 km/s can be derived from the absorption minimum of
Si II 635.5-nm.


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                         (C) Copyright 2015 CBAT
2015 November 24                 (CBET 4203)              Daniel W. E. Green