Central Bureau for Astronomical Telegrams
IAUC 7705: 2001ee; 2001du
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Circular No. 7705
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
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SUPERNOVA 2001ee IN NGC 2347
G. M. Hurst, Basingstoke, England, reports the discovery by M.
Armstrong of an apparent supernova (mag 17) on an unfiltered CCD
image (limiting mag 19) taken on Sept. 1.160 UT in the manner noted
on IAUC 7702 (SN 2001eb). From this image, SN 2001ee was measured
at R.A. = 7h16m04s.12, Decl. = +64o42'19".7 (equinox 2000.0), which
is 5" west and 20" south of the center of NGC 2347. Images taken
by Armstrong on Sept. 5.015 and 5.127 show the new object at mag
17.1 and yield averaged position end figures 04s.14, 19".6.
Nothing is visible at this position on an image obtained by
Armstrong on 2000 Oct. 2 (limiting mag 19.5), and nothing is
present on second Palomar Sky Survey images from 1989 Dec. 23 (red,
limiting mag 20.8), 1997 Mar. 9 (blue, limiting mag 22.5), and 1995
Nov. 16 (infrared). Hurst adds that SN 2001ee is absent from an
image in J. C. Vickers' Deep Space CCD Atlas: North (1993, p. 75;
limiting mag about 19.5).
SUPERNOVA 2001du IN NGC 1365
S. D. Van Dyk, Infrared Processing and Analysis Center,
California Institute of Technology; and W. D. Li and A. V.
Filippenko, University of California at Berkeley, write: "We have
attempted identification of the progenitor of SN 2001du (IAUC 7690,
7692, 7704) on Hubble Space Telescope (HST) archive-image data
originally obtained by GO-5222 (unfortunately, the much deeper Key
Project data obtained by GO-5972 do not contain the site of this
supernova). We have remeasured an accurate position from an image
provided by G. Bock, astrometrically reconstructed to ACT stars:
R.A. = 3h33m29s.10, Decl. = -36o08'31".2 (equinox 2000.0). From
this position, allowing a conservative error of 1".5, we isolate
three possible progenitor stars on the F814W image, with magnitudes
I approximately 23.1, 23.4, and 23.3 (+/- 0.5), in order of
increasing distance from our position. Only the third star (with V
approximately 23.9 +/- 0.5 and V-I = +0.59) actually has a detected
counterpart on the F555W image. The star closest to the position
has a lower limit to its V-I color of about +0.85 mag. Assuming a
distance modulus of 31.31 mag, this star has an absolute I
magnitude of -8.2, which is not inconsistent with what would be
expected for a late-type (red) supergiant star. If the progenitor
was not one of these three stars, we can only place an upper limit
on its absolute brightness at I approximately -7.0. Clearly,
images of the supernova at later times, when it has greatly faded,
must be obtained, preferably with HST, to better pinpoint the
supernova in its environment and to help constrain its nature based
on its stellar and gaseous environment."
(C) Copyright 2001 CBAT
2001 September 5 (7705) Daniel W. E. Green
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