Electronic Telegram No. 3831 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@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network SUPERNOVA 2014ad IN MARKARIAN 1309 = PSN J11574444-1010157 S. Howerton, Arkansas City, KS, U.S.A.; A. J. Drake, S. G. Djorgovski, A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology; J. L. Prieto, Princeton University; M. Catelan, Pontificia Universidad Catolica de Chile; and E. Christensen and S. M. Larson, Lunar and Planetary Laboratory, University of Arizona, report the Catalina Real-time Transient Survey discovery of an apparent supernova in public images from the Catalina Sky Survey (CSS): SN 2014 UT R.A. (2000.0) Decl. Mag. Offset 2014ad Mar. 12.40 11 57 44.44 -10 10 15.7 15.7 3".5 W, 7".2 N The variable was designated PSN J11574444-1010157 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2014ad based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2014ad: Mar. 6.37, [19.0 (CSS); 12.998, 14.7 (Gianluca Masi, Francesca Nocentini, and Patrick Schmeer; remotely using a 43-cm telescope near Ceccano, Italy; position end figures 44s.51, 15".2); 13.258, V = 14.56 +/- 0.03 (Howerton; 0.5-m iT11 robotic telescope near Mayhill, NM, U.S.A.; UCAC4 comparison-star magnitudes); 14.111, 15.1 (F. Luppi and L. Buzzi, Varese, Italy; 0.60-m f/4.6 reflector; position end figures 44s.51, 15".3; a knot or H II region is visible at this position in Digitized Sky Survey images; new image posted at URL http://www.astrogeo.va.it/pub/TOCP/PSN_P37625.jpg); 14.566, 15.2 (Sergio Foglia, Paolo Concari, Gianni Galli, and Maura Tombelli; remotely using a 0.11-m f/5 reflector at the Tzec Maun Observatory, Siding Spring); 14.692, V = 14.77 +/- 0.06 (Howerton; 0.5-m iT30 robotic telescope at Siding Spring); 16.676, R = 14.1 +/- 0.1 (Howerton; 0.32-m f/9.3 Ritchey- Chretien iT9 robotic telescope at Siding Spring; intense moonlight); 17.259, V = 14.0 +/- 0.1 (Howerton; 0.5-m f/6.8 iT11 robotic telescope near Mayhill; intense moonlight). S. W. Jha, V. Pandya, and C. McCully, Rutgers University; R. J. Foley, University of Illinois; and L. Crause, Southern African Large Telescope (SALT) and South African Astronomical Observatory, report that spectra (range 375-920 nm) of PSN J11574444-1010157 = SN 2014ad, taken on Mar. 14.9 and 15.9 UT with SALT (+ RSS), show a blue continuum and broad lines with minima near 440 and 510 nm. Superimposed on the supernova spectra are narrow emission lines from the host galaxy that yield a recession velocity of 1700 km/s, matching the redshift of Mrk 1309 (z = 0.0057; Koribalski et al. 2004, A.J. 128, 16). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) does not yield a convincing match. The spectra resemble early spectra (about 10 days before maximum light) of 1991T-like type-Ia supernovae, but only for a redshift z around 0.04; this is unlikely given the supernova's position in a relatively bright part of Mrk 1309 (= PGC 37625). Moreover, were it in the background at z about 0.04, the supernova would have absolute magnitude around -22. Similarly, SNID matches to the bright, peculiar, "super-Chandra" type-Ia-like supernova 2007if (Scalzo et al. 2009, Ap.J. 713, 1073) are also unlikely. At the distance of Mrk 1309, the supernova's absolute magnitude is around -18, and plausible matches are also found to the spectra of objects like SN 2005hk at about one week before maximum light, though the ejecta velocities compared to line widths are somewhat dissimilar. The spectra also roughly match those of the peculiar supernovae 2002bj and 2005ek soon after explosion (Poznanski et al. 2010, Science 327, 58; Drout et al. 2013, Ap.J. 774, 58). The spectral matches are not exceptionally good, but these events evolve quickly and may have significant diversity. Thus, we suggest that SN 2014ad is a peculiar type-I supernova, either a type-Iax event (Foley et al. 2013, Ap.J. 767, 57) or similar to SNe 2002bj and 2005ek, or perhaps something unique. Continued spectroscopy and photometry of this supernova are encouraged. S. W. Jha, V. Pandya, and C. McCully, Rutgers University; R. J. Foley, University of Illinois; P. M. Garnavich, University of Notre Dame; and L. Crause, Southern African Large Telescope and South African Astronomical Observatory, report that further spectra (range 375-920 nm) of PSN J11574444-1010157 = SN 2014ad, taken on Mar. 16.9, 17.9, and 18.9 UT with the SALT (+ RSS), show the development of broad lines. The spectra have evolved to resemble those of broad-lined type-Ic supernovae like SN 1998bw (Stathakis et al. 1998, MNRAS 314, 807) or SN 2002ap (Foley et al. 2003, PASP 115, 1220), though with some differences in line velocities and shapes. The spectra are posted at URL http://www.physics.rutgers.edu/~saurabh/sn-mrk1309/specevol.png; multi-wavelength follow-up of this unusual supernova is encouraged. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2014 CBAT 2014 March 21 (CBET 3831) Daniel W. E. Green