------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 3124 2015 Nov 19 20.33UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074 INTERNET: GUY@TAHQ.DEMON.CO.UK Backup: gmh@wdcc1.bnsc.rl.ac.uk WORLD WIDE WEB http://www.theastronomer.org ------------------------------------------------------------------- SUPERNOVA 2015Z IN NGC 5837 Further to TA E-Circular 3085 issued as long ago as 2015 June 19, CBET 4171 dated 2015 Nov 15 also relates to the discovery by Ron Arbour of the same supernova in NGC 5837. The new object is located at RA 15h04m40s.78, DEC +12d37'43".6 (2000), 3" east and 16" south of the centre of NGC 5837 (Bootes) Nothing is visible on digitised Palomar Sky Survey plates from 1989 Feb. 11 (red) and 1993 Mar. 19 (blue. The type-Ia supernova 2014ac also appeared in NGC 5837 but not known to be connected with SN 2015Z. D. C. Leonard, San Diego State University and others report optical spectroscopic SN 2015Z observations of 2015 June 20.3 (2.3-m Bok, Kitt Peak). The redshift of NGC 5837 is catalogued as z = 0.0287, from Fisher et al. 1995, Ap.J. Suppl 100, 69, via NED). There does not appear to be significant evolution of the spectra over the one-day time interval. Best matches with spectra are of the peculiar type-IIn event 2009ip taken during the broad peak of its second optical brightening in 2012. SN 2009ip occurred in NGC 7259 found 2009 August 26 at approximately magnitude 17.9 and detected by CHASE project team members. SN 2009ip itself remains a subject of considerable debate, with some contending 2012 events might have been associated with a true supernova? Others propose a non-terminal event (LBV?) (e.g., Moriya et al. 2015, Ap.J. Let. 803, 26, and references therein). The approximate magnitude of SN 2015Z was 17.5R at discovery. The distance modulus to the host galaxy of m-M = 35.25 yields an absolute R-band mag approx -17.8 Dan Green adds: Given similarities of 2015Z to type-IIn events and, especially, to spectra of SN 2009ip during a particularly interesting phase, further observations needed. All wavelengths are encouraged, as are examinations of pre-discovery images to potentially constrain prior outbursts. Editor: It is not clear why there was such a delay between discovery and CBET 4171 issued by the Central Bureau but we congratulate Ron on his discovery and the newly announced designation of SN 2015Z. Guy M Hurst