[IAUC] CBET 3437: 20130312 : SUPERNOVA 2013ak IN ESO 430-20 = PSN J08070669-2803101

Lun Mar 11 21:06:05 ART 2013

                                                  Electronic Telegram No. 3437
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.
e-mail:  cbatiau en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2013ak IN ESO 430-20 = PSN J08070669-2803101
     F. Carrasco, M. Hamuy, R. Antezana, L. Gonzalez, R. Cartier, F. Forster,
S. Silva, P. Sanchez, C. Hervias, and R. Ramirez, Universidad de Chile; G.
Pignata, S. Varela, and Y. Apostolovski, Universidad Andres Bello; F. Aros,
Pontificia Universidad Catolica de Chile; B. Conuel, Wesleyan University; G.
Folatelli, IPMU, University of Tokyo; 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 (which is part of the
Millennium Center for Supernova Science collaboration), report the discovery
of an apparent supernova (mag approximately 13.5) on an unfiltered image taken
on Mar. 9.23 UT with the 0.41-m 'PROMPT 3' telescope located at Cerro Tololo.
CTIO.  The new object is located at R.A. = 8h07m06s.69 +/- 0".2, Decl. =
-28o03'10".1 +/- 0".2 (equinox 2000.0), which is about 25".4 west and 1".8
south of center of the galaxy ESO 430-20.  The variable was designated PSN
J08070669-2803101 when it was posted at the Central Bureau's TOCP webpage and
is here designated SN 2013ak based on the spectroscopic confirmation reported
below.  Additional CCD magnitudes for 2013ak:  Feb. 15.15, 18.5 (CHASE);
Mar. 11.129, 14.1 (Joseph Brimacombe, Cairns, Australia; remotely with a 51-cm
RCOS telescope + luminance filter loated at the New Mexico Skies observatory
near Mayhill, NM, U.S.A.; position end figures 06s.69, 10".2; image posted at
website URL http://www.flickr.com/photos/43846774@N02/8549210863/).

     D. Milisavljevic, Harvard-Smithsonian Center for Astrophysics (CfA); R.
Fesen, Dartmouth College; T. Pickering and A. Kniazev, South African
Astronomical Observatory and Southern African Large Telescope; J. Parrent,
Dartmouth College and Las Cumbres Observatory; and Alicia Soderberg and
Raffaella Margutti, CfA, report that low-dispersion spectra (range 350-880 nm),
obtained on Mar. 10.9 UT with the 10-m SALT telescope (+ RSS), show PSN
J08070669-2803101 = SN 2013ak to be a young type-II supernova not long after
outburst.  Fitting with the SYN++ software (Thomas et al. 2011, PASP 123, 237)
suggests that the broad P-Cyg features seen on a fairly blue continuum are
associated with H_alpha, Na I, Ca II, and He I.  Using a redshift of z =
0.0037, as measured from narrow emission lines associated with a coincident
H II region in the host galaxy (ESO 430-20), they estimate the velocity of the
H_alpha absorption feature to be approximately -18500 km/s.  The spectra
resemble those previously reported for the type-II supernova 2012dy (cf. CBET
3197) and the type-IIb supernova 2011hs (cf. CBET 2902), though in those
objects the Fe II absorptions between 400 and 520 nm were stronger.


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                         (C) Copyright 2013 CBAT
2013 March 12                    (CBET 3437)              Daniel W. E. Green