Electronic Telegram No. 2456

Central Bureau for Astronomical Telegrams
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138,
U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://www.cfa.harvard.edu/iau/cbat.html

G. Pignata and M. Cifuentes, Universidad Andres Bello; J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, P. Gonzalez, S. Silva, G. Folatelli, R. Cartier, F. Forster, and S. Marchi, Universidad de Chile; B. Conuel, Wesleyan University; and D. Reichart, K. Ivarsen, J. Haislip, A. Crain, D. Foster, M. Nysewander, and A. LaCluyze, University of North Carolina at Chapel Hill, on behalf of the CHASE project, report the discovery of an apparent supernova (mag approximately 15.6) on an unfiltered image taken on Aug. 28.07 UT with the 0.41-m 'PROMPT 3' telescope located at Cerro Tololo. The new object is located at R.A. = 23h24m25s.30 +/- 0".1, Decl. = -19°02'14".4 +/- 0".1 (equinox 2000.0), which is on top of the nucleus of the galaxy 2MASX J23242536-1902139. Nothing is visible at this position on archival images taken on Aug. 2.15 (limiting mag 18.5), but 2010hv is also present in images taken on Aug. 18.18 (mag approximately 15.1), on Aug. 24.11 (mag approximately 15.4), and Aug. 31.10 (mag approximately 15.6).

An optical spectrum (range 360-920 nm) obtained with the Las Campanas 2.5-m du Pont telescope (+ WFCCD) on Sept. 14.2 UT by N. Morrell, Las Campanas Observatory, Carnegie Supernova Project; and Ismael Botti and Paula Lopez, Universidad de Chile, reveals that 2010hv is a type-II supernova, showing a blue continuum with the characteristic P-Cyg profiles in the Balmer lines and strong galactic contamination. A redshift of 7279 km/s (s.d. 13 km/s) is derived from an average of ten emission lines from the underlying H II region, superimposed on the supernova spectrum. Considering that redshift, the minimum of the H-beta absorption is blueshifted by 7400 km/s. Interstellar Na I absorption at the same redshift is observed with an E.W. of 0.08 nm. Cross-correlation with a library of supernova spectra using the Supernova Identification tool (Blondin and Tonry 2007, Ap.J. 666, 1024) suggests that this supernova is of subtype II-p with ages ranging from 15 to 40 days.

NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars.

2010 September 15
(C) Copyright 2010 CBAT
(CBET 2456 )
Daniel W. E. Green