Discovery of a Luminous Supernova, PTF10hgi

ATel #2740; R. M. Quimby, S. Kulkarni, E. Ofek, M. M. Kasliwal (Caltech), A. Gal-Yam, I. Arcavi, S. Ben-Ami, D. Xu, A. Sternberg (Weizmann Institute), J. M. Silverman, S. B. Cenko, I. K. W. Kleiser (Berkeley), P. E. Nugent (LBNL), D. A. Howell (LCOGT/UCSB) on behalf of the PTF Collaboration
on 15 Jul 2010; 21:01 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Robert Quimby (quimby@astro.as.utexas.edu)

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The Palomar Transient Factory (ATel #1964) reports the discovery of a new supernova, PTF10hgi, located at RA = 16:37:47.04, Dec = +06:12:32.3 (J2000). PTF10hgi was detected on May 15.46 UT with an R-band magnitude of 19.1 (calibrated with respect to the USNO-B catalog). PTF10hgi brightened to 18.0 mag on June 20.30 UT.

Initial spectroscopic observations on May 21 with the Palomar 5.1-m Hale Telescope (+DBSP) and again on June 11 with the Lick 3-m telescope (+KAST) show blue continua with subtle line features. However, a third Lick/KAST spectrum taken on July 7 is similar to the luminous supernova, PTF09cnd (Quimby et al. 2009) at about 3 weeks past maximum light. Using the PTF09cnd spectrum as a template, we find an approximate redshift of z~0.1.

We requested Swift UVOT observations, which were carried out on July 13. Neglecting any contribution from the host galaxy, we measure the following preliminary magnitudes for the transient:

  
   MJD     Filter   Mag   Mag_err  
55390.8164     U   18.11   0.11  
55390.8125  UVW1   19.29   0.22  
55390.7852  UVM2   19.97   0.27  
55390.8203  UVW2   19.94   0.24  

Additional observations are underway. We thank the Swift team for scheduling the ToO observations.