2009CBET.1988....2R

Spectra were taken of 2009kf, 2009ki, and 2009kb with the GMOS spectrograph on the Gemini-North 8-m telescope on July 30.31, July 31.28, and Aug. 19.34 UT by S. Rodney, C. Trundle, S. Valenti, and A. Pastorello. SN 2009kf is a type-II-P supernova at z = 0.18, showing an expansion velocity from the P-Cyg H-alpha absorption of about 9300 km/s. PS1 lightcurve data supplemented with images from the William Herschel Telescope and the Liverpool Telescope indicate a peak absolute magnitude of M_r about -18.3 (assuming no reddening), suggesting that 2009kf is likely to be one of the most luminous type-II-P supernovae known. SN 2009kf was detected in the near ultraviolet (NUV) via GALEX Time Domain Survey (TDS) observations at 10 to 20 days after the supernova discovery, yielding a peak magnitude of [NUV] = 22.34 ± 0.17. The host galaxy of 2009kf is detected in pre-supernova GALEX TDS observations with [NUV] = 21.58 ± 0.15; the GALEX FUV detector was temporarily not operational during the observations. Further observations and analysis are ongoing. The host galaxy of 2009ki was detected with narrow emission lines, confirming a redshift at z = 0.107. A host-galaxy signal was detected for 2009kb, but no redshift could be determined.

All of the objects are associated (i.e., within 2 arcsec) with a host galaxy detected in Sloan Digital Sky Survey (SDSS) DR7 images, apart from 2009ke, which initially appeared hostless; the deep PS1 stacked image before detection of 2009ke on June 10.95 shows a faint host galaxy, ELAIS09(R) J160724.7+5400, which has been catalogued as a galaxy in the Kitt Peak National Observatory ELIAS field R-band survey of Fadda et al. (2004, A.J. 128, 1). None of the host galaxies have SDSS spectroscopic SDSS data, and all redshifts listed above are photometric redshifts apart from 2009kf and 2009ki. These discoveries were made with the PS1 System (for additional information, see website URL http://ps1sc.org/PS1_System_IAU.htm).