Electronic Telegram No. 1569
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
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SUPERNOVA 2004iq
     E. Kankare and S. Mattila, Tuorla Observatory; S. Ryder, Anglo-Australian
Observatory; A. Alonso-Herrero, T. Diaz Santos, and L. Colina, Instituto de
Estructura de la Materia, Consejo Superior de Investigaciones Cientificas
(CSIC); J. Kotilainen and H. Lehto, Tuorla Observatory; M. A. Perez-Torres,
C. Romero-Canizales, and A. Alberdi, Instituto de Astrofisica de Andalucia,
CSIC; P. Vaisanen, South African Astronomical Observatory; and A. Efstathiou,
European University of Cyprus, report the discovery of an apparent supernova
in near-infrared images of the luminous infrared galaxy IRAS 17138-1017.  The
new object was detected in F110W, F160W, and F187N NICMOS images obtained
with the Hubble Space Telescope on 2004 Sept. 23.0 UT, located at R.A =
17h16m35s.900, Decl. = -10o20'37".85 (equinox 2000.0), which is 1".50 east
and 1".12 north of the galaxy's H-band nucleus; 2004iq has magnitudes
18.3, 17.0, and 16.6 in the F110W, F160W, and F187N bands, respectively --
consistent with the core-collapse supernova template light curves of Mattila
and Meikle (2001, MNRAS, 234, 235) with a total line-of-sight extinction of
up to six magnitudes in V.  Nothing is visible at the position of 2004iq in
J, H, and K-band Altair/NIRI adaptive-optics images obtained with the
Gemini-North Telescope on 2008 June 25.5 to limiting magnitudes of
approximately 22.0, 20.5, and 20.0, respectively.  No known minor planets
were near the source within 10' at the time of the NICMOS observations.
Thanks to the high spatial resolution (FWHM about 0".15) of the data, they
were able to determine that the source was stationary with a precision of
0".02 when compared to the field stars between the first and the last
NICMOS images that were separated by about 40 minutes.  This rules out any
solar-system object (Delta < 10000 AU) as the origin for the transient
source, as it would have a proper motion larger than 0.1 arcsec/hour.
Furthermore, due to the high ecliptic latitude (about 13 deg) of IRAS
17138-1017, a minor planet close to its stationary point can also be ruled
out as the origin of the source.  A variable foreground star also provides
a very improbable alternative explanation, given the small field-of-view
(19".8 x 19".8) of the NICMOS frames.  Based on these arguments and the
fact that large numbers of core-collapse supernovae are expected in the
nuclear regions of IRAS 17138-1017 as a result of the large star-formation
rate therein (Kankare et al. 2008, Ap.J. Let., accepted;
http://lanl.arxiv.org/abs/0810.2885) it is concluded that explanations
other than a supernova for this object are extremely unlikely.  Searches
of non-publicly-accessible observatory archives for observations in 2004
and 2005 that could include IRAS 17138-1017 are encouraged.


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

                         (C) Copyright 2008 CBAT
2008 November 11                 (CBET 1569)              Daniel W. E. Green