Central Bureau for Astronomical Telegrams
IAUC 3339: A0535+26 = HDE 245770; V843 Oph SN REMNANT; PRESUMABLY Var ULTRAVIOLET-EXCESS OBJECT
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Read IAUC 3340
Circular No. 3339
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
A0535+26 = HDE 245770
M. R. Sims and G. W. Fraser, X-Ray Astronomy Group, Leicester
University, report the observation of a further outburst of the
recurrent x-ray transient A0535+26 (IAUC 3078, 3154, 3208) with the
Ariel 5 ssi. The intensity has risen from 0.006 times Crab
strength (2-18 keV) on Feb. 26 to 0.25 Crab strength on Mar. 18,
with the last four days of increase being particularly rapid.
Optical observations of the 9th-magnitude counterpart HDE 245770 (IAUC
3167) and x-ray-pulse-timing measurements would be valuable.
V843 OPHIUCHI SUPERNOVA REMNANT
A. N. Bunner, Space Physics Group, University of Wisconsin,
writes: "Analysis of data from the Wisconsin Soft X-Ray Experiment
on OSO 8 has revealed soft x-rays from the location of the Kepler
1604 supernova V843 Oph remnant at l ~ 4o.5, b ~ +7o. The source
was observed primarily between 0.5 and 1.5 keV. It was observed
continuously during 1976 Mar. 11-17 and is distinguished from the
nearby source GX 1+4 by the spectral gap between this soft-source
spectrum and the heavily absorbed GX 1+4 spectrum. The spectral
signature and observed constancy of the flux of the new source over
the six-day observation period suggest that the 1972-73 transient
4U 1730-22 (also close to V843 Oph) is probably not responsible."
PRESUMABLY VARIABLE ULTRAVIOLET-EXCESS OBJECT
B. Takase, Tokyo Astronomical Observatory, communicates: "T.
Noguchi, H. Maehara and M. Kondo have discovered an ultraviolet-excess
object on a UGR three-image plate taken with the 105-cm
Schmidt telescope at the Kiso Station. Exposures were 40, 100 and
20 min for U, G and R, respectively, beginning on 1978 Dec. 26.735
UT. The position of the object is R.A. = 9h31m15s.15, Decl. = +40o51'31".4
(equinox 1950.0), and the estimated magnitude and colors in the
Kiso system are G = 17.3, G-R = -0.1, and U-G = -1.6, respectively.
Inspection of two plates covering the same area taken on 1978 Dec.
6 and 1979 Jan. 7 reveals that the object was then too faint to be
detected, G being fainter than the limiting magnitude of ~ 18.5.
On the Palomar Sky Survey prints, the blue image is much brighter
than the red, and the star is in fact the bluest in the surrounding
region.
1979 March 23 (3339) Daniel W. E. Green
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