SN 2011ff (A.R. 22 45 02.27, Dec. +34 00 15.0) scoperta il 22 agosto 2011 nella galassia UGC 12179 (offset 18W 20N), magnitudine 16.8, tipo Ia.
SN scoperta da Simone Leonini e Giacomo Guerrini con il telescopio Ritchey Chretien da 53 cm di diametro dell'osservatorio di Montarrenti (Siena).
UGC 12179 è una galassia S0 nella costellazione del Pegaso, distante 98 Mpc, magnitudine 14.15.
Electronic Telegram No. 2793
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University;
20 Oxford St.; Cambridge, MA 02138; U.S.A.
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SUPERNOVA 2011ff IN UGC 12179 = PSN J22450228+3400150
Simone Leonini, Siena, Italy, reports the discovery by S. Leonini and G.
Guerrini of an apparent supernova (mag about 16.8) on an unfiltered CCD image
(limiting mag about 18.9) taken on Aug. 22.969 UT at the Montarrenti
Observatory in the course of the Italian Supernovae Search Project using a
0.53=m f/8.7 Ritchey-Chretien telescope (+ Apogee Alta U47 CCD camera). The
new object is located at R.A. = 22h45m02s.28, Decl. = +34d00'15".0 (equinox
2000.0), which is 18" west and 30" north of the nucleus of the galaxy UGC
12179. No stellar source is visible at this position on Palomar Sky Survey
plates from 1953 Oct. 2 (J) and 1994 Aug. 29 (F), though no limiting
magnitudes were provided by Leonini. The discovery image is posted at URL
http://tinyurl.com/3u74vg8. The variable was designated PSN J22450228+3400150
when it was posted at the Central Bureau's TOCP webpage and is here designated
SN 2011ff based on the spectroscopic report below. Additional CCD magnitudes
for 2011ff (unfiltered unless noted otherwise): 1989 Sept. 8, [19.5 (Palomar
Sky Survey N plate; via Leonini); 2009 Sept. 17, [19.2 (Leonini); 2011 July
30, [19.2 (Leonini); Aug. 23.934, 16.5 (A. Dimai, Col Drusci, Italy); Aug.
23.95, 16.7 (Leonini; limiting mag about 18.5); Aug. 24.276, 16.8 (Joseph
Brimacombe, Cairns, Australia; position end figures 02s.90, 15".9; image
posted at website URL http://www.flickr.com/photos/43846774@N02/6077986697/);
24.28, 17.4 (R. A. Koff, Bennett, CO, U.S.A.; Meade 0.25-m f/10 reflector +
Apogee AP-47p CCD camera; limiting mag 19.5; position end figures 02s.82,
15".4); 24.577, 17.2 (Brimacombe; infrared filter; position end figures
02s.93, 15".9). Koff adds that nothing is visible at the position of 2011ff
on the Digitized Sky Survey, providing the limiting mag as 19.5 but providing
no bandpass or date for the plate.
D. D. Balam, Dominion Astrophysical Observatory, National Research Council
of Canada (NRCC); M. L. Graham, Las Cumbres Observatory Global Telescope,
University of California at Santa Barbara; E. Y. Hsiao, Lawrence Berkeley
Laboratory; and D. W. E. Green, Harvard University, report that a spectrogram
(range 383-717 nm; resolution 0.3 nm) of PSN J22450228+3400150 = SN 2011ff,
obtained on Aug. 25.33 UT with the 1.82-m Plaskett Telescope of the NRCC,
shows it to be a type-Ia supernova near maximum light. Cross-correlation with
a library of supernova spectra using the "Supernova Identification" code
(Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2011ff is most
similar to the type-Ia supernova 2004eo at 2 days past maximum light.
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2011 CBAT
2011 August 27 (CBET 2793) Daniel W. E. Green