Central Bureau for Astronomical Telegrams
IAUC 6171: GRS 1915+105; V1974 Cyg; NOTICE RE Tlgms
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Circular No. 6171
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
Phone 617-495-7244/7440/7444 TWX 710-320-6842 ASTROGRAM CAM
MARSDEN@CFA.HARVARD.EDU or GREEN@CFA.HARVARD.EDU (science)
GRS 1915+105
K. Ebisawa and N. E. White, Goddard Space Flight Center, NASA;
T. Kotani, Institute of Space and Astronautical Science; and A.
Harmon, Marshall Space Flight Center, NASA, communicate: "The
Galactic superluminal jet source GRS 1915+105 (Mirabel and
Rodriguez 1994, Nature, 371, 46) was observed to be unusually
bright with the ASCA satellite on Apr. 20.4-20.9. The flux in the
band 2-10 keV was about 5 x 10E-9 erg cmE-2 sE-1 or 0.26 Crab. The
spectrum is well fit by a power-law with photon index 1.4 between 1
and 5 keV, and it is significantly absorbed by cold matter
corresponding to a hydrogen column density of 5 x 10E22 cmE-2.
Above 5 keV, the spectrum decays exponentially with an e-folding
energy of 5 keV. The near simultaneous BATSE flux in the band 20-
100 keV was < 50 mCrab, confirming the strong high-energy cut-off.
The ASCA spectrum and the BATSE flux are similar to those in the
1994 Sept. observations, and the overall spectrum seems much softer
than that during the 1992-1993 outburst, when the source was bright
in both soft and hard x-rays. Follow-up x-ray and radio
observations are encouraged."
V1974 CYGNI
V. Elkin, Special Astrophysical Observatory, writes: "CCD
spectrograms (range 649-661 nm, resolution 0.075 nm) of V1974 Cyg
obtained on 1994 Oct. 15-16 with the 6-m telescope (+ Main Stellar
Spectrograph) show a broad H-alpha emission line split into several
components. The central narrow emission feature (FWHM = 0.1 nm)
may belong to a vast diffuse cloud larger than 33" (which is the
length of the spectrograph slit); this feature has radial velocity
v(r) = -19.2 +/- 1.0 km/s, which is near that of the interstellar
Ca II 396.8-nm line (v(r) = -25.8 +/- 1.4 km/s) as seen in the
early nebular stage; such a cloud may be interstellar and thus not
connected with the nova eruption. A Gaussian analysis yielded the
relative intensities of H-alpha to N II 654.8-nm to N II 658.4-nm
as 100:10:30."
NOTICE CONCERNING TELEGRAMS
Because of the steady decline in telegram communications in
recent years, with very few telegram messages received by the
Central Bureau in recent months, it is planned that the Bureau's
TWX number (710-320-6842) will be retired as of 1995 July 1. The
Bureau ceased transmitting telegram messages in 1993 (cf. IAUC 5873).
1995 May 11 (6171) Daniel W. E. Green
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