Electronic Telegram No. 588 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://cfa-www.harvard.edu/iau/cbat.html SUPERNOVA 2006dz IN NGC 5185 C. Contreras and G. Folatelli, on behalf of the Carnegie Supernova Project, report the discovery of an apparent supernova present on Sloan u', g', r', i', and Johnson-Cousin B and V CCD images obtained between May 31 and June 12 with the 2.5-m du Pont telescope and the 1-m Swope telescope, both at Las Campanas Observatory. The new object is located at R.A. = 13h30m00s.37, Decl. = +13o24'43".1 (equinox 2000.0), which is 30" west and 15" south of the nucleus of NGC 5185. This occurred almost simultaneously with the brighter supernova 2006br in the same host galaxy (cf. IAUC 8705). Nothing is visible at the location of 2006dz on images obtained with the Swope telescope on May 17 (limiting r' magnitude > 21.7 at 3-sigma level). The available magnitudes (after subtracting SDSS images of the host galaxy around the supernova) for 2006dz are tabulated below. The "e" columns in the table are statistical uncertainties in magnitudes, as estimated from photon statistics on the images. 2006 UT g' e(g') r' e(r') i' e(i') Telescope May 31.14 21.15 0.03 20.04 0.02 19.69 0.02 du Pont June 4.10 20.02 0.03 19.02 0.02 18.74 0.02 Swope June 5.15 19.92 0.05 18.97 0.02 18.69 0.02 Swope June 7.10 19.97 0.02 18.93 0.02 18.61 0.02 du Pont June 8.09 20.08 0.04 18.94 0.02 18.60 0.02 du Pont June 11.07 20.27 0.04 19.00 0.02 18.64 0.02 du Pont June 12.09 20.40 0.05 19.05 0.02 18.70 0.02 du Pont Discovery images and graphs of the light curves can be seen at http://csp1.lco.cl/~cspuser1/objX/ NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2006 CBAT 2006 July 26 (CBET 588) Daniel W. E. Green