SN 2012ex in ugc 838 - 10 settembre 2012

Stampa

SN 2012ex (A.R. 01 18 45.97 Dec. +14 59 40.2) scoperta il 16 settembre 2012 nella galassia UGC 838 (offset 2E 4N), magnitudine 15.5, tipo Ib.

SN scoperta dal Catalina Real-Time Transient Survey (USA) il 16.280 settembre e indipendentemente da S. Leonini, G. Guerrini, P. Rosi, D. Soldateschi and L.M. Tinjaca Ramirez con il telescopio RC 0.53m f/8.7 dell'Osservatorio di Montarrenti (SI) il 10.9099 di setttembre e confermata il 16.9625 settembre.

                                                  Electronic Telegram No. 3234
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 2012ex IN UGC 838 = PSN J01184597+1459402
S. Howerton, Arkansas City, KS, U.S.A.; A. J. Drake, S. G. Djorgovski,
M. J. Graham, A. Mahabal, and R. Williams, California Institute of Technology;
J. L. Prieto, Princeton University; M. Catelan, Pontificia Universidad
Catolica de Chile; and E. Christensen and S. M. Larson, Lunar and Planetary
Laboratory, University of Arizona, report the discovery of an apparent
supernova in public images from the Catalina Sky Survey (CSS).

SN       2012 UT        R.A. (2000.0) Decl.      Mag.      Offset
2012ex   Sept. 16.28   1 18 45.97  +14 59 40.2   17.5    1".8 E, 4".5N

The variable was designated PSN J01184597+1459402 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2012ex based on the
spectroscopic confirmation reported below.

Simone Leonini, Siena, Italy, reports the independent discovery by G.
Guerrini, P. Rosi, D. Soldateschi, L. M. Tinjaca Ramirez, and himself of this
apparent supernova at mag about 15.5 on an unfiltered CCD image (limiting mag
about 18.0) taken on Sept. 10.9097 UT at the Montarrenti Observatory in the
course of an automatic survey 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. = 1h18m46s.05, Decl. = +14d59'39".9 (equinox
2000.0), which is 2" east and 3" north of the nucleus of the galaxy UGC838.
Nothing is visible at this position on Palomar Sky Survey red and blue plates
(1987 Aug. 24, N plate; 1989 Nov. 4, J plate; 1994 Dec. 1, F plate) to
limiting mag about 19.5.  Leonini notes that their discovery image is posted
at URL
http://www.astrofilisenesi.it/public/Sne/Uploads/PSN_in_UGC00838.jpg;
their confirming image can be viewed at URL
http://tinyurl.com/9bg5bgy.
Additional CCD magnitudes for 2012ex:  2012 Feb. 1.13 UT, [19.0 (CSS); Aug.
24, [18.5 (Leonini et al.);
Sept. 16.962, 17.8 (Leonini et al.; limiting mag
18.5); Sept. 17.371, 17.7 (Joseph Brimacombe, Cairns, Australia; remotely
using a 51-cm RCOS telescope + STL11K camera + luminance filter at the New
Mexico Skies Observatory near Mayhill, NM, U.S.A.; position end figures
45s.97, 40".2); 18.067, 17.8 (Federica Luppi and Luca Buzzi, Varese, Italy;
0.38-m f/6.8 reflector; position end figures 46s.08, 39".3; reference stars
from CMC-14 catalogue).  Brimacombe's image posted at the following URL:
http://www.flickr.com/photos/43846774@N02/7998673206/.  Luppi's image is
posted at website URL http://www.astrogeo.va.it/pub/TOCP/PSN_U838.jpg).

M. Turatto, M. L. Pumo, S. Vanni, S. Benetti, A. Pastorello, L. Tomasella,
P. Ochner, E. Cappellaro, and S. Valenti, Osservatorio Astronomico di
Padova,
Istituto Nazionale di Astrofisica, report that a spectrogram of PSN
J01184597+1459402 = SN 2012ex, obtained on Sept. 18.00 UT with the Asiago
1.82-m Copernico Telescope (+ AFOSC; range 340-820 nm; resolution 1.4 nm),
shows very strong He lines that are typical of type-Ib supernovae.  Adopting
for the host galaxy (UGC 838) the redshift z = 0.0229 (SDSS1; via NED), the
best fit with the GELATO tool (Harutyuyan et al. 2008, A.Ap. 488, 383) on a
vast library of supernovae spectra is with SN 1999dn (Benetti et al. 2011,
MNRAS 411, 2726) at one day before maximum.


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

(C) Copyright 2012 CBAT
2012 September 21                (CBET 3234)              Daniel W. E. Green