2009CBET.1754....1Q

Further to CBET 1732, R. Quimby, California Insitute of Technology – together with M. M. Kasliwal, S. B. Cenko, D. Fox, A. Gal-Yam, D. A. Howell, S. R. Kulkarni, N. Law, D. Levitan, A. Mahabal, P. Nugent, E. O. Ofek, D. Poznanski, and R. Thomas, on behalf of the larger "Palomar Transient Factory" (PTF) collaboration – report the discovery of numerous optical transients with the Palomar Observatory 1.2-m Oschin Schmidt telescope (+ CFH12K camera). Imaging data were obtained on several nights between Mar. 17 and 28 with a g-band filter. The transients were identified after subtracting off reference templates (having mean limiting g-band magnitude 21.9) that were constructed from imaging data obtained prior to Mar. 12. Spectroscopic follow-up was carried out on Mar. 27, 28, 29, 30, and 31 with the 9.2-m Hobby-Eberly Telescope (+ LRS), the 5.1-m Palomar Hale telescope (+ DBSP), and the 10.0-m Keck-I telescope (+ LRIS). Included in the tabulation below are the discovery date for each object and g-band magnitude at that time. The confirmed supernovae below are all type-Ia events except for 2009cq and 2009cv (possible type-II supernovae), 2009ct (type-II), and 2009cw (possible type-IIn supernova). SN 2009cb was independently discovered via the Catalina Sky Survey (cf. CBET 1752).

---------------------------------------------------------------------------— SN 2009 UT R.A. (2000.0) Decl. Mag. Offset z ---------------------------------------------------------------------------— 2009cb Mar. 25.164 12 59 15.85 +27 16 41.3 19.1 1".7 W, 5".5 N 0.19 2009cg Mar. 17.188 12 26 17.84 +48 26 49.5 20.9 5".3 W, 6".3 N 0.19 2009ch Mar. 20.283 10 51 08.55 +74 05 23.2 20.5 3".9 E, 1".9 N 0.18 2009ci Mar. 21.196 11 33 20.71 - 9 24 40.3 19.0 0".0 W, 0".2 N 0.12 2009cj Mar. 21.216 9 45 30.46 + 6 32 25.0 17.8 0".2 W, 1".5 N 0.09 2009ck Mar. 21.360 9 22 15.69 +45 44 53.4 19.5 0".0 E, 0".1 N 0.17 2009cl Mar. 21.385 13 21 45.15 +42 33 06.2 20.2 0".8 W, 1".2 N 0.25 2009cm Mar. 21.428 11 54 42.23 +55 18 10.7 20.1 0".1 W, 0".4 N 0.19 2009cn Mar. 21.431 11 03 06.64 +50 09 36.3 19.8 0".6 W, 1".4 N 0.20 2009co Mar. 21.435 12 24 35.31 +47 14 16.8 19.2 6".1 W, 1".2 N 0.16 2009cp Mar. 25.152 9 15 12.73 +19 05 46.3 20.2 2".0 W, 2".9 S 0.22 2009cq Mar. 25.161 11 46 50.12 +11 47 55.3 19.6 2".6 W, 0".7 S 0.11 2009cr Mar. 25.163 11 18 06.46 +12 53 43.1 18.0 0".1 E, 1".3 N 0.14 2009cs Mar. 25.262 14 15 19.36 +16 25 14.0 19.7 4".7 W, 4".5 S 0.17 2009ct Mar. 26.251 13 15 23.15 +46 25 09.4 17.9 7".5 W, 3".9 S 0.06 2009cu Mar. 26.251 13 29 12.64 +46 43 27.5 19.3 0".2 E, 0".9 N 0.10 2009cv Mar. 27.161 11 42 13.88 +10 38 54.0 20.3 5".6 W, 5".2 N 0.15 2009cw Mar. 28.404 15 05 01.97 +48 40 03.9 20.3 0".8 W, 0".7 N 0.15 2009cx Mar. 28.416 12 24 39.20 + 8 55 59.2 20.5 1".6 W, 0".8 N 0.18 ---------------------------------------------------------------------------—

Following are the discovery observations for three possible supernovae, with their offsets from nearby possible host galaxies:

---------------------------------------------------------------------------— PSN 2009 UT R.A. (2000.0) Decl. Mag. Offset ---------------------------------------------------------------------------— K0903-1 Mar. 21.186 11 16 34.27 + 3 32 02.8 20.1 0".2 W, 2".1 N K0903-2 Mar. 26.209 14 30 50.42 +35 37 31.4 18.8 4".2 E, 3".3 S K0903-3 Mar. 26.230 14 10 18.54 +16 53 38.8 19.0 4".7 E, 3".9 N ---------------------------------------------------------------------------—

PSN K0903-1 has redshift z = 0.19. PSN K0903-2 was not spectroscopically confirmed; however, from its proximity to a galaxy in the Sloan Digital Sky Survey catalogue (z = 0.03), it is likely to be a supernova. Spectra of PSN K0903-3 show a nearly featureless blue continuum. Additional g-band magnitudes: PSN K0903-1, Mar. 25.160, 20.1; PSN K0903-2, Mar. 27.257, 18.9; PSN K0903-3, Mar. 28.420, 18.8.

Two variable stars were also found as tabulated below:

-----------------------------------------------------------------— Constellation 2009 UT R.A. (2000.0) Decl. Mag. -----------------------------------------------------------------— Cam Mar. 17.134 4 05 02.73 +73 24 54.2 18.5 Cnc Mar. 20.141 8 07 29.72 +15 34 41.8 16.9 -----------------------------------------------------------------—

The variable in Cam was detected on a single night over 2 hr; no source was detected at that position during a spectroscopic observation on Mar. 31 with the Keck telescope (+ LRIS), and this significant fading suggests a dwarf nova. The transient in Cnc was spectroscopically determined to be a cataclysmic variable star.