Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits


The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).

Read IAUC 5341  SEARCH Read IAUC 5343
IAUC number

                                                  Circular No. 5342
Central Bureau for Astronomical Telegrams
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

     J. Watanabe, National Astronomical Observatory; and T.
Nakamura, M. Tsutsumi, T. Tsuda and S. Kato, Radio Atmospheric
Science Center, University of Kyoto, report that preliminary
analysis of radar observations in Japan during Aug. 12.54-14.88 UT
shows that the Aug. 12.7 Perseid activity peak described by Y.
Taguchi (IAUC 5330, 5340) is clear in the strong radar echoes, but
not in the weak echoes.  The hourly number of strong echoes (signal-
to-noise ratio > 40 dB) during the critical interval on Aug. 12
and 13 was: Aug. 12.60, 34; 12.65, 63; 12.69, 51; 12.73, 67;
13.60, 23; 13.65, 25; 13.69, 32; 13.73, 24.  High-altitude ( > 95
km) meteor echoes also increased significantly: Aug. 12.60, 57;
12.65, 103; 12.69, 125; 12.73, 75; 13.60, 37; 13.65, 54; 13.69,
55; 13.73, 63.  On the other hand, the number of weak echoes
during Aug. 13.6-13.8 was greater than during Aug. 12.6-12.8.
They add that the radar results suggest an increase in high-
velocity meteors such as Perseids around the peak time but that
this was due only to the larger particles.

     R. Sunyaev, M. Gilfanov, A. Goldurm and M. C. Schmitz-Fraysse, on
behalf of the Granat team (Space Research Institute, Moscow; Centre
d'Etude Spatale des Rayonnements, Toulouse; Service d'Astrophysique du
CEA, Saclay), report: "Observations of the GX 340-0 (Ara X-1) field
were performed with GRANAT on Aug. 21-22.  GX 340-0 itself was detected
by the ART-P telescope at a level of 220 mCrab in the 4-20 keV band,
and the 3-sigma upper limit in the 40-92 keV band was 30 mCrab (SIGMA
data).  GX 339-4 was detected by SIGMA in a very bright state, about
320 mCrab in the 40-150 keV band, confirming the BATSE results on IAUC
5327; this source was detected up to about 200 keV with a power-law
photon index of about 2.1 and flux about 1.9E-4 photon s-1 cm-2 keV-1
at 100 keV.  The pulsar OAO 1657-415, also detected by SIGMA, gave
barycentric P = 37.6726 +/- 0.0015 s, indicating further spin-up since
an ART-P observation on Feb. 18 gave P = 37.7897 +/- 0.0003 s.  4U
1700-37 was detected close to the edge of the SIGMA field of view at a
level of 190 mCrab in the 40-150 keV band.  Further GRANAT observations
on Aug. 29-30 show that GX 339-4 continues to be in bright state with
30-150 keV flux about 330 mCrab.  GRANAT observations of the region are
also scheduled on Sept. 2, 6 and 25."

1991 September 11              (5342)              Brian G. Marsden

Read IAUC 5341  SEARCH Read IAUC 5343

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!