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IAUC 7366: 2000H; XTE J1543-568; N Sgr 2000

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                                                  Circular No. 7366
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)

     P. Garnavich, University of Notre Dame; and P. Challis, S.
Jha, and R. Kirshner, Harvard-Smithsonian Center for Astrophysics,
report that a spectrum of SN 2000H was obtained by K. Rines on Feb.
9.2 UT with the F. L. Whipple Observatory 1.5-m telescope, showing
it to be a type-Ia supernova.  The characteristic Si II 615-nm
absorption is present, but with a pronounced asymmetric profile,
being very steep on the red side of the line.  Assuming a recession
velocity of 4170 km/s, based on the narrow emission from the host
galaxy, the photospheric velocity from the Si II absorption minimum
is only -4100 km/s.  The 580-nm feature is deep relative to the Si
II, which suggests that this is a subluminous, fast-declining event.
The peak observed magnitude of 17 (IAUC 7361) also suggests a very
low luminosity for a type-Ia event.

XTE J1543-568
     M. H. Finger, Universities Space Research Association, and C.
A. Wilson, Marshall Space Flight Center, NASA, report for the
Compton Gamma Ray Observatory (CGRO) BATSE team:  "Pulsations from
the newly discovered x-ray pulsar XTE J1543-568 (IAUC 7363) are
being detected in the hard x-ray band with BATSE.  Detectable
pulses are found in BATSE data beginning on Jan. 25; from the data
of Jan. 25.0-Feb. 2.0 UT, a frequency of 36.86162(6) mHz at Jan.
29.0 and a frequency rate of 1.41(6) x 10**-11 Hz/s were determined.
The pulse profile is double-peaked, with one peak being less than
half the height of the other.  The pulsed flux (mean minimum) for
this interval was 11 +/- 3 mCrab (20-50 keV), and the mean flux
measured using earth occultations was 32 +/- 12 mCrab (20-50 keV).
The pulse frequency increased to 36.87211(14) mHz by Feb. 8.0, and
the pulsed flux to 20 +/- 4 mCrab, as determined from the data of
Feb. 6.0-8.0.  No occultation fluxes were available in this
interval because of the CGRO spacecraft orbit."

     Visual magnitude estimates by A. Pearce, Nedlands, W.
Australia:  Feb. 12.829 UT, 12.0; 13.819, 12.4.

                      (C) Copyright 2000 CBAT
2000 February 14               (7366)            Daniel W. E. Green

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