Central Bureau for Astronomical Telegrams
IAUC 8212: 2003ik; 2003il
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Circular No. 8212
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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CBAT@CFA.HARVARD.EDU (science)
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Phone 617-495-7440/7244/7444 (for emergency use only)
SUPERNOVA 2003ik IN MCG +11-10-56
Further to IAUC 8210, T. Boles reports the discovery of an
apparent supernova (mag 16.6) on unfiltered CCD images taken on
Sept. 29.081 and 29.911 UT. The new object is located at R.A. =
8h04m06s.52, Decl. = +62o59'19".8, which is approximately 9".4 west
and 18".1 north of the center of MCG +11-10-56. SN 2003ik is not
present on Boles' images from Aug. 29 and Sept. 3 (limiting mag
19.5) or on Palomar Sky Survey red or blue plates.
SUPERNOVA 2003il
A. Gal-Yam, D. Maoz, E. O. Ofek, D. Poznanski, K. Sharon, E.
Medezinski, and Y. Lipkin, Tel Aviv University; F. Prada, Isaac
Newton Group of Telescopes, Instituto de Astrofisica de Canarias;
and P. Guhathakurta, University of California at Santa Cruz, report
their discovery of an apparent supernova (V about 23) on unfiltered
images taken by Ofek on Mar. 26 with the 2.5-m Nordic Optical
Telescope (+ ALFOSC imaging spectrograph) at La Palma. The new
object is located at R.A. = 16h35m47s.5, Decl. = +66o13'26".9
(equinox 2000.0), in the field of the galaxy cluster Abell 2218 (z
= 0.175). SN 2003il was invisible in images obtained in Apr. and
June 2002 (limiting mag V about 25.0). P. Challis, T. Matheson,
and R. Kirshner report that this object is confirmed in V, R, and I
frames obtained with the 6.5-m MMT telescope (+ MINICAM) on 2003
May 5. Gal-Yam and Sharon add that inspection of deep archival
images of Abell 2218, obtained with the Hubble Space Telescope
(broad-V F606W filter in Jan. 2000; broad-R F702W filter in Sept.
1994), reveals no sources near the location of SN 2003il (limiting
magnitude equivalent to V = 27). These strong limits on the
luminosity of possible host galaxies suggests that this supernova
may be yet another example of the class of intergalactic supernovae
in clusters (Gal-Yam et al. 2003, A.J. 125, 1087). The distance of
SN 2003il from the cluster core is 76" (233000 pc, assuming a flat
cosmology and a Hubble constant of 70 km/s/Mpc). Using the colors
measured from the imaging data obtained by Challis et al. (I = 23.4
+/- 0.12, R = 23.6 +/- 0.16, V = 24.5 +/- 0.16), combined with the
color-classification tools of Poznanski et al. (2002, PASP 114,
833), Gal-Yam et al. find that SN 2003il is consistent with a type-
Ia supernova at the redshift of the cluster, discovered some months
after peak magnitude, which is also possibly somewhat underluminous
for its age (by about 1 mag). They add that the supernova colors
can also be explained by a higher-redshift event (i.e., behind the
cluster Abell 2218) exploding in an undetected low-luminosity dwarf
host.
(C) Copyright 2003 CBAT
2003 September 29 (8212) Daniel W. E. Green
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