Electronic Telegram No. 953 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2007ce Further to IAUC 8622, R. Quimby, University of Texas, reports the discovery of an apparent supernova (at mag about 17.4) in unfiltered CCD images taken around May 4.14 UT using the 0.45-m ROTSE-IIIb telescope at the McDonald Observatory. SN 2007ce is located at R.A. = 12h10m17s.96, Decl. = +48o43'31".5 (equinox 2000.0), which is coincident with an unresolved source of magnitude r about 22.2 in the Sloan Digital Sky Survey catalogue that is itself at the edge (1".8 west and 3".2 south from the core) of a galaxy of magnitude r about 19.5. The new object was found by subtracting a co-addition of ROTSE-IIIb images taken between 2005 Apr. 12 and 2007 Mar. 18 (limiting mag about 18.6), and it was not detected in ROTSE-IIIb data from 2007 Apr. 24.12 (limiting mag about 17.8). A spectrum (range 420-890 nm), obtained on May 4.28 with the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by S. C. Odewahn and E. Terrazas, shows 2007ce to be a type-Ic supernova. Strong, narrow emission lines from H-alpha, H-beta, H-gamma, and O III 495.9- and 500.7-nm indicate a redshift of z = 0.046. The spectrum is roughly similar to that of SN 2007bg a few days after maximum light (CBET 927, 948), but with weaker absorption around rest frame 605 nm. Photometry at the Palomar 1.5-m telescope by A. Rau and E. O. Ofek detected 2007ce at magnitudes g = 17.64 +/- 0.10 (May 4.421), r = 17.46 +/- 0.10 (May 4.429), and i' = 17.40 +/- 0.15 (May 4.437). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 May 6 (CBET 953) Daniel W. E. Green