Electronic Telegram No. 2503
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@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVAE 2010iu AND 2010iv
     J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, R. Cartier, and F. Forster,
Universidad de Chile; G. Pignata and M. Cifuentes, Universidad Andres Bello; P.
Gonzalez, Pontificia Universidad Catolica de Chile; B. Conuel, Wesleyan
University; G. Folatelli, Institute for the Physics and Mathematics of the
Universe (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, report the discovery
of an apparent supernova (mag approximately 17.4) on unfiltered images taken
on Oct. 15.26 and 16.09 UT with the 0.41-m 'PROMPT 1' telescope located at
Cerro Tololo.  The object, designated SN 2010iv, is located at R.A. =
4h03m52s.23 +/- 0".2, Decl. = -43o25'38".5 +/- 0".2 (equinox 2000.0); it is
right on the top of the small galaxy and completely dominating the visible
light.  Nothing is visible at this position on a stack of seventeen 40-s
archival images taken between 2009 Nov. 5.13 and 2010 Aug. 13.28 (limiting
mag 19.5).

     G. Pignata, Universidad Andres Bello; and G. Folatelli, IPMU, University
of Tokyo, on behalf of the Millennium Center for Supernova Science, report on
optical spectroscopy (range 355-890 nm) of 2010iv (see above) and the object
announced on CBET 2499 (and now designated 2010iu), obtained with the SOAR
4.3-m telescope (+ Goodman HTS) on Oct. 16.3 UT.  The spectra show both
objects to be normal type-Ia supernovae, a few days before maximum.
Following cross-correlation with a library of supernova spectra using SNID
(Blondin and Tonry 2007, Ap.J. 666, 1024), 2010iv is found to be most similar
to SN 2003du at three days before maximum; SNID also provides a best-fit
redshift of 0.074 for 2010iv.  SN 2010iu is most similar to SN 1992A at five
days before maximum (via SNID).  The Si II 597.2-nm line appears stronger in
SN 2010iu than in SN 1992A.  SNID also provides a best-fit redshift of 0.040
for SN 2010iu.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2010 CBAT
2010 October 17                  (CBET 2503)              Daniel W. E. Green