Central Bureau for Astronomical Telegrams
IAUC 3342: OAO 1653-40; Aql X-1; JUPITER
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Read IAUC 3343
Circular No. 3342
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
OAO 1653-40
N. E. White, S. H. Pravdo and J. H. Swank, Goddard Space
Flight Center, write: "An 8-hr HEAO-A2 pointed observation of OAO
1653-40 on 1978 Sept. 4 revealed the x-ray source to be modulated
with a period of 38.22 +/- 0.01 s. The peak-to-mean amplitude ranged
from 10 percent in the 2-10-keV band to 30 percent in the 8-25
keV."
M. Johnston, T. Armstrong and the HEAO-1 Scanning Modulation
Collimator Team at the Massachusetts Institute of Technology and
the Center for Astrophysics report that their analysis of the above
pointed observation of the OAO 1653-40 region confirms the presence
of the pulsing x-ray source. Pulsations are detected only in the
5.5-13.5-keV energy band. Multiple lines of position are obtained
for the source, but none of them is consistent with the position of
V861 Sco, the suggested counterpart of OAO 1653-40 (IAUC 3234;
Polidan et al. 1978, Nature 275, 296). An upper limit of < 1.0
uJy is placed on the 1.5-13.5-keV flux density of V861 Sco during
the pointed observation.
AQUILA X-1
L. J. Kaluzienski and S. S. Holt, Goddard Space Flight Center,
report the detection of an x-ray outburst from a position consistent
with that (i.e., within the ~ 2o error circle) of the recurrent
transient Aql X-1. Observations with the Ariel-5 all-sky
monitor in the instrument coarse-spatial-resolution mode indicate
that this latest flare may have commenced as early as Mar. 14, the
flux (3-6 keV) remaining at a relatively low level (<~ 0.2 Crab)
through Mar. 19. The source apparently brightened to a level of
0.3-0.4 Crab on Mar. 20, and fine-mode observations on Mar. 26 and
27 indicate an intensity of ~ 0.5 Crab. It is noted that the last
flare observed from this source occurred in 1978 June (IAUC 3235).
JUPITER
Corrigendum. In the final paragraph on IAUC 3338, it should
have been made clear that the observations of Jupiter's ring were
due to E. E. Becklin and C. G. Wynn-Williams, and that those of
the [O II] emission were due to C. B. Pilcher and J. S. Morgan.
In the third line from the end, the intensity ratio should have
been given as I_3726/I_13729 > 1, rather than I_3726/I_3729 >> 1.
1979 April 6 (3342) Brian G. Marsden
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