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IAUC 6073: X-RAY N IN Sco; AG Dra

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                                                  Circular No. 6073
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM     EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


X-RAY NOVA IN SCORPIUS
     R. M. Hjellming and M. Rupen, National Radio Astronomy
Observatory, report the results of Very Large Array radio observations
of GRO J1655-40:  "Ten epochs of 22.5-GHz images of the resolved
radio source, from Aug. 18 to Sept. 5, show a linear expansion of
two components at an angular rate of 0".056 +/- 0".012 (3-sigma)
per day on a line with a position angle of 54o, with expansion
beginning Aug. 12.6 UT.  If the distance is 3.5 kpc (IAUC 6062),
this expansion rate corresponds to a separation velocity of 1.1c
perpendicular to the line of sight.  Preliminary indications are
that the southwestern component is stable at a position R.A. =
16h54m00s.14 +/- 0s.02, Decl. = -39o50'44".9 +/- 0".9 (equinox
2000.0), and the apparent motion is mostly from the northeastern
component moving away from this position.  Because of this behavior,
astrometric work on the optical and radio positions of this object
is urgently needed.  On Sept. 5.2, the radio source's intensity was
0.3, 0.15, 0.13, 0.11, and 0.09 Jy at 1.49, 4.9, 8.4, 14.9, and
22.5 GHz, respectively.  In addition to the general trend of a flux
decay with an e-folding time of about 6 days, at frequencies below
5 GHz, there was an additional about 0.3 Jy component in the light
curves at higher frequencies that appeared about Aug. 27, and which
was present only in the southwestern component.  There are also
indications of variability on time scales of tens of minutes to
hours in the same component.  Part of the southwest component seems
to be behaving like the fluctuating, slowly-decaying radio sources
seen after the transient events in GRS 2023+338 and GRO J0422+32,
and may be synchrotron radio emission in the outer portions of
accretion-disk outflows."


AG DRACONIS
     K. Petrik and L. Hric provide the following photometry obtained
at the Hlohovec Public Observatory, Slovakia (comparison stars BD
+67o925, HD 145991; estimated errors to last digit given
parenthetically): July 12.05 UT, V = 8.55(3), B-V = +0.45(5), U-B =
-1.08(6); 14.97, 8.52(2), +0.41(4), -0.81(9); 15.95, 8.55(1),
+0.24(3), -0.94(6); 16.01, 8.51(1), +0.44(4), -1.23(4); 16.95,
8.50(2), +0.59(3), -1.25(1); 16.97, 8.57(2), +0.27(3), -1.23(4);
Aug. 9.89, 8.68(2), +0.47(3), -0.85(6); 9.93, 8.63(1), +0.51(3),
-0.96(4); 15.87, 8.75(1), +0.49(2), -1.15(3).


1994 September 8               (6073)            Daniel W. E. Green

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