Central Bureau for Astronomical Telegrams
IAUC 4060: Sco X-1; NGC 6212; PKS 0537-441; PW Vul (N Vul 1984 No. 1)
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Read IAUC 4061
Circular No. 4060
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 617-495-7244/7440/7444
SCORPIUS X-1
J. Middleditch and W. Priedhorsky, Los Alamos National Laboratory,
communicate: "In a search for coherent x-ray pulsations from
Sco X-1 we find quasiperiodic fast variability. Fourier analysis
of 34 ks of EXOSAT ME data starting on Feb. 26.151 UT shows excess
power between 4 and 9 Hz, corresponding to a 3-percent rms flux
variation. The power spectrum peak has a fwhm of 1 Hz, a centroid
near 6 Hz and a statistical significance of 100-sigma. This variability
was present only in the last half of the data, when the source was
quiescent; it was absent earlier when the source was flaring (to a
limit below 1 percent rms of the quiescent flux). This feature may
be similar to that reported by van der Klis et al. in GX 5-1 (IAUC
4043) and/or to the 0.6-Hz 'noisar' feature in AM-Her binaries
(Middleditch 1982, Ap.J. 257, L71)."
NGC 6212
P. Biermann, Max-Planck-Institut fur Radioastronomie, Bonn;
R. G. Strom, Radiosterrenwacht, Dwingeloo; and N. Bartel, Center
for Astrophysics, communicate: "We have identified a strong variable
x-ray source, observed three times with the IPC on the Einstein
satellite, with the elliptical galaxy NGC 6212, a few arcmin
from the quasar 3C 345. Westerbork observations at 327, 609, and
1412 MHz show the presence of an unresolved radio source with a
nonthermal spectrum centered on the galaxy. The strong x-ray
variability and the presence of radio emission suggest an active
nucleus in NGC 6212, possibly a new BL-Lac object or optically-
violent variable. The optical position is R.A. = 16h41m41s92 +/- 0s.09,
Decl. = +39deg53'55"8 +/- 1" (equinox 1950.0), in agreement with the
radio and x-ray positions. Optical spectroscopy is highly desirable."
PKS 0537-441
S. Cristiani, European Southern Observatory, reports that the
CCD photometry on Jan. 10 (IAUC 4027) gave V = 15.60 (Jan. 10.207
UT), and a further observation on Jan. 12.215 UT gave V = 15.18.
PW VULPECULAE (NOVA VULPECULAE 1984 No. 1)
Visual magnitude estimates by M. Verdenet, Bourbon-Lancy,
France: Mar. 25.1 UT, 10.9; Apr. 1.1, 10.8; 3.1, 10.8; 20.1, 10.9.
1985 May 13 (4060) Brian G. Marsden
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