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An Early Type Ia SN detection by LSQ and GMOS classification

ATel #4212; E. Hadjiyska (Yale), J. Parrent (LCOGT/Dartmouth), D. Rabinowitz (Yale), C. Baltay (Yale), N. Ellman (Yale), R. McKinnon (Yale), U. Feindt (U. Bonn), P. Nugent (LBNL), D. A. Howell (LCOGT/UCSB), B. Dilday (LCOGT/UCSB)
on 25 Jun 2012; 23:37 UT
Credential Certification: Ellie Hadjiyska (ellie.hadjiyska@yale.edu)

Subjects: Optical, Supernovae, Transient

We report the discovery of a Type Ia SN on June 22.41 (when the variable was at magnitude R = 15.8 and detection of the same on June 16.43 with a pre-discovery magnitude of R = 18.9), as part of the La Silla-QUEST (LSQ) transient survey. Photometry is calibrated to the USNO-B1.0 catalog. The source's position is RA = 20:58:51.91, Dec = -02:58:27.2 (J2000). A CCD spectrum (range 350-900 nm) was taken with Gemini South on June 24 UT, showing that LSQ12dbr is a young type Ia supernova at a redshift of z=0.019. We also note that the Si II 635.5-nm absorption feature consists of two separate absorptions of Si II, corresponding to line-of-sight velocities of 9600 and 13500 km/s. A weak absorption feature, likely due to C II 657.8-nm, is also present - these signatures and our Superfit (Howell et al. 2005, Ap.J. 634, 1190) comparisons suggest an epoch of ~9 days pre-maximum light. Photometry was obtained on the 2m Faulkes Telescope South and calibrated directly to the Sloan Digital Sky Survey. The resulting magnitudes, at MJD=56102.63, are g`=15.91 +/- 0.04, r`=15.94 +/- 0.03 and i`=16.26 +/- 0.03.