Central Bureau for Astronomical Telegrams
IAUC 2774: X-RAY SOURCES; NOTICE TO Tlgm SUBSCRIBERS
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Read IAUC 2775
Circular No. 2774
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Cable Address: SATELLITES, NEWYORK
Western Union: RAPID SATELLITE CAMBMASS
X-RAY SOURCES
C. J. Eyles, G. K. Skinner and A. P. Willmore, University of
Birmingham; and F. D. Rosenberg and R. Berthelsdorf, Mullard Space
Science Laboratory, report: "A new, transient x-ray source has been
observed by Ariel 5. It was first observed on Apr. 21 and by Apr.
28 was brighter in x-rays than the Crab Nebula (the peak brightness
being 1500 Uhuru counts per second or possibly more). Our best estimate
of the position is R.A. = 5h35m54s.0, Decl. = +26o17'18" (equinox
1950.0), with an error circle about this of 60" in radius. We suggest
that this object would justify observations at other wavelengths
in view of the relatively small error box."
E. W. Gottlieb and W. Liller, Center for Astrophysics, Harvard
and Smithsonian Observatories, report that X Per, the irregular
variable star identified with the x-ray source 3U 0352+30, has been
fading steadily since early 1974 and now is fainter than at any
time since 1936. According to plates in the Harvard collection, X
Per has varied irregularly since 1895 between B = 5.9 and 7.0.
Recent B magnitudes derived from patrol plates taken at Harvard's
Agassiz Station are as follows:
1974 UT B 1974 UT B 1974/75 UT B
Jan. 28.0 6.0 Oct. 10.3 6.7 Dec. 7.1 6.8
Feb. 14.0 6.1 18.3 6.6 Jan. 5.1 6.8
20.9 6.2 Nov. 10.2 6.6 Apr. 20.0 6.8
Sept.24.4 6.6 23.2 6.7 21.0 6.8
NOTICE TO TELEGRAM SUBSCRIBERS
The above information from Eyles et al. was telegraphed to the
"G" list (Astrogram Gamma) in the hope that rapid communication
would indeed lead to observations of the x-ray source at other
wavelengths. Subscribers are invited to comment on the desirability
of communicating information about transient x-ray sources in
this manner. The telegraphed information was abbreviated to conform
as far as possible to the telegraphic code, and we should welcome
advice on how the code could be modified to make it more suitable
for handling observations of this type (and also perhaps observations
of outbursts of radio sources).
1975 May 5 (2774) Brian G. Marsden
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