| ASU Astronomers discover Supernova in nearby void galaxy CGCG 223-029 |
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ASU astronomers
R.A. Jansen and
K. Tamura in collaboration
with N.A. Grogin (Johns Hopkins University) today reported their discovery of
an apparent supernova in
UBVRI images of star-bursting early-type spiral galaxy
CGCG 223-029 (R.A.=16h
02m16s.63,
Decl.=+42°55'00.9" J2000.0), obtained with the CCD camera on the
1.8 m
Vatican Advanced Technology Telescope (VATT) of the
Mt.Graham International Observatory,
AZ.
Jansen first found the conspicuous point-like object on 2005 April 02.46 UT
in two 300 sec R filter CCD images. It is located 4.5" East
and 5.6" South of the nucleus, i.e., at R.A.=16h
02m17s.04,
Decl.=+42°54'55.3" J2000.0. Jansen and Tamura confirmed the object to
be stationary on subsequent nights: 2005 April 04.4, 2005 April 05.4,
2005 April 06.4 and 2005 April 07.5 UT.
Both a Sloan Digital Sky Survey - Data
Release 3 finding-chart image (shown above, left panel) and a
F.L. Whipple
Observatory
48" telescope
R-filter CCD image obtained by Grogin on 1995 May 31.4 UT show the
object to be absent from these earlier data. Via subtraction of the
48" R image, the R magnitude of the supernova on 2005 April
02.46 UT was measured as 17.95 ± 0.05 mag.
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The picture at the left is a color composite of B, V and R
filter images obtained by ASU graduate students Jason Cook and Russell Ryan
on 2005 April 12.3 UT using the CCD camera at the
Braeside 16" Cassegrain Telescope.
Although the resolution (FWHM) is only ~3 arcsec, the supernova is clearly
detected.
(Click on the image to enlarge.)
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Per IAU Circular #8512, the supernova is confirmed and has received the designation
SN 2005bk.
M. Ganeshalingam and collaborators from the University of California at
Berkeley report that inspection of CCD spectra, obtained on April 17 UT with
the Shane 3 m telescope at Lick Observatory and spanning the
range 3,300Å—10,000Å, show that SN 2005bk is of type
Ic, similar to SN 1994I (Fillipenko et al. 1995, ApJ 450, L11) about
one week past maximum light. This would imply that Jansen, Tamura & Grogin
discovered the supernova a few days before maximum light.
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