corrected version of ATel #4297 - PTF Discovery of PTF12gzk - A Peculiar Type I Supernova

ATel #4298; Sagi Ben-Ami (Weizmann), Avishay Gal-Yam (Weizmann), Alexei V Filippenko (UCB), Joseph W. Richards (UCB), Assaf Horesh (Caltech), S. Bradley Cenko (UCB), Iair Arcavi (Weizmann), Joshua S. Bloom (UCB), Yi Cao (Caltech), Andy Howell (LCOGT/UCSB), Mansi Kasliwal (Carnegie/Princeton), Shri Kulkarni (Caltech), Thomas Matheson (NOAO), Paolo Mazzali (INAF), Maryam Modjaz (NYU), Nick Moskovitz (Carnegie), Peter Nugent (LBNL), Eran Ofek (Weizmann), Jerod Parrent (Dartmouth College/Las Cumbres Observatory), David Sand (LCOGT/UCSB), Jeffrey M. Silverman (UCB), Nathan Smith (University of Arizona), Mark Sullivan (Oxford), Ofer Yaron (Weizmann)
on 4 Aug 2012; 20:17 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Avishay Gal-Yam (avishay.gal-yam@weizmann.ac.il)

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The Palomar Transient Factory (ATEL \#1964; http://www.astro.caltech.edu/ptf ) reports the discovery of a new supernova, PTF12gzk. The object was discovered on 2012 July 24 UT at RA(J2000) = 22:12:41.53 and DEC(J2000) = +00:30:43.1 at a magnitude of 20.1 in the R band (calibrated with respect to the USNO catalog), in the dwarf galaxy SDSS J221241.53+003042.7 (redshift z = 0.0137). It was not detected down to mag 20.6 (3 sigma) in previous PTF images taken on July 19. On July 30 the SN reached a magnitude of 16 in the R band. A spectrum of PTF12gzk was obtained on July 27 using the Double Spectrograph (Oke et al. 1982, PASP, 94, 586) mounted on the Palomar 5-m Hale telescope, revealing the object to be an unusual Type I supernova. Spectra obtained on Aug 2 UT using the SNIFS spectrograph (Lantz et al. 2004, Proc. SPIE, 5249, 146) mounted on the UH 2.2-m telescope and the GMOS Spectrograph (Hook et al. 2004, PASP, 116, 425) mounted on the Gemini North 8-m telescope appear similar to those of the peculiar Type Ic SN 2004aw (Taubenberger et al. 2006, MNRAS, 371, 1459 ). PTF12gzk was observed by the X-Ray Telescope (XRT; Burrows et al. 2005, Space Science Review, 120, 165) and the ultraviolet imaging telescope (UVOT; Mason et al. 2004, Proc. SPIE, 5165, 277) on the Swift satellite. XRT measurements, beginning at 13:39 UT on July 31, detected no source at the location of PTF12gzk at this time. We estimate a dead-time corrected limit on the XRT count rate of <2E-3 cps. Assuming a power-law spectrum with a photon index of 2, this corresponds to a limit on the X-ray flux of <7E-14 erg cm^-2 s^-1. UVOT observations, beginning at 11:30 UT on July 31, showed that PTF12gzk has a magnitude of 18.32 in UVW1 (260 nm), corresponding to a flux of 8E-16 erg cm^-2 s^-1. On July 31 we triggered our Hubble Space Telescope Target of Opportunity (ToO) program for STIS UV spectroscopy of a stripped-envelope supernova (Cycle 19, GO-12530; PI Filippenko). The first visit will occur on August 7, the second on August 11, and the third on August 15. ToO JVLA and CARMA radio observations have been initiated and additional observations are ongoing as well. We encourage intensive monitoring at all wavelengths.