Central Bureau for Astronomical Telegrams
IAUC 6210: Cyg X-1; X-RAY N 1994 IN Sco; 41P
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Circular No. 6210
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
Phone 617-495-7244/7440/7444 (for emergency use only)
CYGNUS X-1
W. Paciesas, D. Crary, G. Fishman, B. A. Harmon, C.
Kouveliotou, and S. N. Zhang, Marshall Space Flight Center, NASA,
report for the Compton Observatory BATSE team: "Since about June
28, the blackhole-candidate binary system Cyg X-1 (= HDE 226868)
has been in a state of unusually intense low-frequency noise. The
power spectrum of the 20- to 100-keV emission between 0.005 and 0.5
Hz shows the typical shape for Cyg X-1: flat at low frequencies and
falling off roughly as 1/f at high frequencies. However, the total
power in the low-frequency noise increased by a factor of about 3
between June 28 and July 30, while the break frequency dropped from
about 0.08 to about 0.04 Hz, similar to the effect seen at lower
energies by Belloni and Hasinger (1990, A.Ap. 227, L33). The
increased noise is not correlated with source intensity. Individual
Cyg X-1 flares with timescales of order 1-10 s have triggered the
burst detection algorithm aboard BATSE > 30 times since June 28.
Continuous BATSE monitoring has shown no similar level of activity
in Cyg X-1 since 1991 Nov."
X-RAY NOVA 1994 IN SCORPIUS
H. Inoue, F. Nagase, and Y. Ueda report on behalf of the ASCA
team: "ASCA observed GRO J1655-40 during Aug. 15.45-16.18 UT. The
average flux in the range 2-10 keV was 3.4 x 10E-8 erg cmE-2 sE-1
(about 1.6 Crab, remaining within +/- 10 percent of this throughout),
and was about 3 times as bright as that in the previous ASCA
observation in 1994 Sept. (IAUC 6094). The preliminary spectral
analysis shows that the 1- to 10-keV spectrum can be reproduced by
a power law with an exponential cutoff and with a photoelectric
absorption. The best-fit photon index, folding energy, and
absorption column are 0.5, 2 keV, and 8 x 10E21 cmE-2, respectively."
COMET 41P/TUTTLE-GIACOBINI-KRESAK
Total visual magnitude estimates (cf. IAUC 6207): Aug. 19.36
UT, 7.7 (D. Seargent, The Entrance, N.S.W., 25x100 binoculars);
20.17, 8.3 (C. S. Morris, Lockwood Valley, CA, 0.26-m reflector;
tails 8' and 4' long in p.a. 110 deg and 335 deg, and faint
northward fan of connecting material in between); 20.93, 8.9 (J. G.
de S. Aguiar, Campinas, Brazil, 11x80 binoculars).
1995 August 22 (6210) Daniel W. E. Green
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