2012CBET.3174....2P

J. T. Parrent, Las Cumbres Observatory Global Telescope (LCOGT) and Dartmouth College; and D. A. Howell, LCOGT and University of California at Santa Barbara, report that an optical spectrum (range 350-970 nm) of PSN J20233626-2816434 = SN 2012dn was obtained on July 10.2 UT with the Gemini Multi-Object Spectrograph (GMOS) on the 8-m Gemini South telescope. Cross- comparisons with a library of supernovae spectra via "Superfit" (Howell et al. 2005, Ap.J. 634, 1190) suggest that 2012dn is a type-Ia supernova approximately a week before maximum light. After removal of a host-galaxy recession velocity of 2958 km/s for PGC 64605, the Si II 635.5-nm absorption minimum is seen to be blueshifted by 12000 km/s. In addition, the detection of a strong C II 657.8-nm absorption feature (blueshifted by 12200 km/s) and comparisons to pre-maximum spectra of SN 2006gz (Hicken et al. 2007, Ap.J. 669, L17), SN 2007if (Scalzo et al. 2010, Ap.J. 713, L1073), and SN 2009dc (Yamanaka et al. 2009, Ap.J. 707, L118) suggest that 2012dn is a super-Chandra event.