Central Bureau for Astronomical Telegrams
IAUC 3420: X-RAY FLARE IN Lup; OPTICAL/X-RAY Obs IN 1980; P/SCHWASSMANN-WACHMANN 1
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Circular No. 3420
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
X-RAY FLARE IN LUPUS
L. Kaluzienski and S. Holt, Goddard Space Flight Center, report
the detection with the Ariel 5 all-sky monitor of an x-ray
flare from a source in the constellation Lupus. The source
appeared during Oct. 25d09h-25d14h UT, attained a peak 3-6-keV
intensity of ~ 0.33 Crab on Oct. 26 and faded back below detectable
levels early on the 27th. Upper limits to the flux during ~ 0.5-day
periods adjacent to the flare are ~ 0.1 Crab. Fine-mode observations
of this region conducted on Oct. 19-20 and 28 yield corresponding
upper limits of ~ 0.05 Crab. The source is located at R.A. =
15h13m, Decl. = -43o.2 (equinox 1950.0), with a 90-percent-confidence
error-circle radius of ~ 2o. It is noted that the observed flare
timescale is intermediate between those of previously reported x-ray
flares (cf. IAUC 3174) and the x-ray novae and that no known
x-ray sources lie within the error Circle.
OPTICAL/X-RAY OBSERVATIONS IN 1980
W. Lewin and L. Cominsky, Massachusetts Institute of Technology,
communicate: "Dark time has been made available by M. Oda on
Hakucho (Japan) and may also be made available by K. Pounds on UK 6
(England) for simultaneous optical and x-ray observations of x-ray
burst sources with faint optical counterparts. The periods during
which the observations will be made are 1980 Apr. 9-23, May 9-23,
June 7-21, July 7-21 and Aug. 7-21. The objects to be studied are
MXB1636-53 (from which 15 optical bursts were recorded during the
1979 observations; cf. IAUC 3399), MXB1735-44 (IAUC 3230), MXB1837+05
(IAUC 3331), and possibly MXB1659-29 (IAUC 3190, 3229), 4U 1608-52
(IAUC 3349) and Cen X-4 (IAUC 3362, 3366), depending on burst
activity. Participation by optical observers is invited. Large
telescopes (apertures ~ 1.5 m or larger) are needed because the
optical counterparts are faint (mv > 17). Astronomers who are
interested in participating should contact us (telephone 617-253-4282,
telex 92-1473 MIT CAM, TWX 710-320-0058 MIT CAM)."
PERIODIC COMET SCHWASSMANN-WACHMANN 1
J. Bortle, Brooks Observatory, informs us that he observed
this comet visually at m1 = 12.7 (0.32-m reflector, 88 x) on Oct.
31.40 UT. The coma, of diameter 0'.7, was moderately condensed.
There is a current ephemeris on MPC 4833.
1979 November 6 (3420) Brian G. Marsden
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