Central Bureau for Astronomical Telegrams
IAUC 5327: 1991ao; 1991ap; GX 339-4
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Circular No. 5327
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
SUPERNOVA 1991ao IN UGC 270
C. Pollas, Observatoire de la Cote d'Azur, reports his discovery,
on tech pan films obtained Aug. 16.1 and 17.1 UT, of a supernova
of mag about 17.8 located at R.A. = 0h25m17s.67, Decl. =
+32 30'06".5 (equinox 1950.0) in the galaxy UGC 270 (R.A. =
0h25m18s.69, Decl. = +32 29'55".5). A nearby star of mag 16 is at
R.A. = 0h25m20s.41, Decl. = +32 29'34".3. A. V. Filippenko and T.
Matheson, University of California at Berkeley, report that a CCD
spectrum (range 390-710 nm, resolution 1 nm) obtained on Aug. 19 UT
with the Shane 3-m reflector at Lick Observatory shows that SN
1991ao is of type II, within a few weeks past maximum brightness.
The hydrogen Balmer lines are very strong and exhibit P-Cyg profiles.
The redshift of the parent galaxy, measured from an H II
region in a spiral arm, is about 0.016.
SUPERNOVA 1991ap IN ANONYMOUS GALAXY
Pollas reports his discovery, on the same films mentioned
above, of another apparent supernova (mag 19) in a spiral galaxy
(mag 15.5) located at R.A. = 0h15m46s.70, Decl. = +31 44'32".0
(equinox 1950.0). The supernova is located at R.A. = 0h15m46s.94,
Decl. = +31 43'57".4. Both films reach a limiting magnitude of 21;
nothing is visible on the Palomar Observatory Sky Survey prints. A
nearby star of mag 17.5 is at R.A. = 0h15m45s.93, Decl. =
+31 43'36".4.
GX 339-4
G. Fishman, R. Wilson, C. Meegan, A. Harmon, and M. Brock,
Marshall Space Flight Center, NASA; W. Paciesas, University of
Alabama at Huntsville; and M. Finger, Gamma Ray Observatory (GRO)
Science Support Center, report, for the BATSE experiment team on the
GRO: "BATSE has been performing nearly full-sky monitoring of hard
x-ray and gamma-ray sources since its launch in April (IAUC 5214).
During the past month, a hard x-ray source consistent with the location
of GX 339-4 has exhibited greatly-increased flux above 20 keV,
along with a hard spectrum to at least 200 keV. The present flux is
the maximum so far observed. The following flux values were
measured relative to the Crab in the approximate energy bands 20-40
keV, 40-100 keV, and 100-230 keV: June 16-28, < 0.04, < 0.02, <
0.03; July 13-25, 0.18, 0.17, 0.17; Aug. 9-12, 0.37, 0.37, 0.31."
1991 August 19 (5327) Daniel W. E. Green
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