Central Bureau for Astronomical Telegrams
IAUC 7361: 2000H; AX J0043-737
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Circular No. 7361
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 2000H IN IC 454
Independent discoveries of an apparent supernova in IC 454
have been reported by M. Armstrong, Rolvenden, Kent, England, on
unfiltered CCD images taken on Feb. 7.97 and 8.03 UT (mag about 17)
for the U.K. Nova/Supernova Patrol with a 0.30-m telescope, and by
M. Papenkova and W. D. Li, University of California at Berkeley, on
behalf of the Lick Observatory Supernova Search (cf. IAUC 6627,
7126), on unfiltered CCD images taken on Feb. 8.18 and 8.22 (mag
about 17.3) with the 0.8-m Katzman Automatic Imaging Telescope
(KAIT). KAIT measurements show that the new object is located at
R.A. = 6h51m07s.67, Decl. = +12o55'18".5 (equinox 2000.0), which is
19".6 east and 0".2 south of the nucleus of IC 454. Armstrong
provides the following position end figures from his exposure on
Feb. 8.782: 07s.60, 18".4 (or 25" east and 2" north of the galaxy
center). G. M. Hurst, Basingstoke, England, notes that confirming
images taken by S. Foulkes, Ashperton Village, on Feb. 8.812 and by
T. Boles, Wellingborough, on Feb. 9.11 show SN 2000H near mag 17.
SN 2000H also appears on earlier KAIT images taken on Jan. 27.2
(mag about 19.0) and Feb. 2.2 (mag about 17.3). Earlier patrol
images by Armstrong appear to show the new object on Jan. 23.016
(trace) and 25.938 (mag 18.5; limiting mag 19.0). SN 2000H does
not appear on CCD frames taken on 1999 Dec. 5 (limiting mag 19.0)
and 2000 Jan. 4/5 by Armstrong, or on a KAIT image taken on Jan.
8.2 (limiting mag about 20.0). Armstrong adds that nothing is
visible at the location of SN 2000H on the second Palomar Sky
Survey image.
AX J0043-737
J. Yokogawa and K. Koyama, Kyoto University, write: "An ASCA
observation of the Small Magellanic Cloud (SMC) on 1999 May 10-11
detected coherent pulsations of period 87.58073 +/- 0.00004 ms with
a significance of 99.98 percent from AX J0043-737, which is located
at R.A. = 0h42m35s, Decl. = -73o40'30" (equinox 2000.0; +/- 1' at
90-percent confidence). The spectrum was described by a power law
with photon index 1.7 (+0.9,-0.5). The x-ray flux in the band
0.7-10.0 keV was 2.0 x 10**-13 erg s**-1 cm**-2, corresponding to a
luminosity of 8.6 x 10**34 erg/s for a distance of 60 kpc. We
suggest that AX J0043-737 is a Crab-like pulsar in the SMC,
although the possibility of an x-ray binary with a short pulse
period is not excluded. Within the ASCA error region, a ROSAT
source RX J0042.6-7340 is found (Kahabka et al. 1999, A.Ap. Suppl.
136, 81). Confirmation attempts at x-ray, radio, and other
wavelengths are encouraged."
(C) Copyright 2000 CBAT
2000 February 9 (7361) Daniel W. E. Green
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