Central Bureau for Astronomical Telegrams
IAUC 3238: 4U 1658-48; 4U 0115+63; A0327+43
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Read IAUC 3239
Circular No. 3238
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
4U 1658-48
The HEAO-A3 Group, in collaboration with J. Grindlay, Center
for Astrophysics, announce the identification of 4U 1658-48 = GX
339-4 with a star of mv ~ 16.5 at R.A. = 16h59m01s.9, Decl. = -48o43'06"
(equinox 1950.0). In view of the x-ray flaring reported below,
continued monitoring of this stellar object would be useful.
F. Li, G. Clark and S. Rappaport, Massachusetts Institute of
Technology, report that SAS-3 observations of 4U 1658-48 during the
interval June 21.6-23.2 UT indicate that the source was in a
high-intensity state with a flux (1-6 keV) of~ 0.4 Crab. This flux is
~ 3 times higher than when the source was last observed by SAS 3 on
May 25. The intensity is apparently steady on timescales of 10 to
500 seconds.
4U 0115+63
W. Wheaton, Massachusetts Institute of Technology, and the
HEAO-A4 experimenters there and at the University of California at
San Diego report the discovery of a strong absorption feature near
20 keV in the pulsed spectrum of the transient x-ray binary 4U
0115+63 (cf. IAUC 3163, 3171). The observations were made during
Jan. 16d13h23m-16d16h01m UT (when the orbital phase relative to
periastron of 4U 0115+63 was 0.35 +/- 0.01). Referred to the pulsed
spectrum, the absorption feature has an equivalent width of ~ 2 keV.
It is possible that the feature is due to cyclotron absorption. A
cyclotron emission line was reported earlier for Her X-l by Trumper
et al. (1978, Astrophys. J. 219, L105); see also IAUC 3184.
A0327+43
M. Ricketts, R. Gowan and R. Warwick, Leicester University,
report that the Ariel 5 ssi has detected a new x-ray source, designated
A0327+43, at the position R.A. = 3h27m.7 +/- 0m.3, Decl. = +43o.2 +/- 0o.6
(equinox 1950.0); the strength was ~ 0.01 Crab flux units. The
first ssi scan over this region since 1977 Feb. was on 1978 June
16, and the source was still visible on June 26. Data up to 1977
Feb. give a strength upper limit (3-sigma) for a steady source of 0.002
Crab flux units. It is noted that GK Per (Nova Per 1901) is in the
error box.
1978 June 30 (3238) Brian G. Marsden
Read IAUC 3239
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