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IAUC 4763: 3C 390.3; CY UMa; 1989B

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                                                  Circular No. 4763
Central Bureau for Astronomical Telegrams
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

3C 390.3
     W. Wamsteker and J. Clavel, IUE Observatory, Madrid, report:
"Observations of the radio galaxy 3C 390.3 on Mar. 22 with the
International Ultraviolet Explorer (IUE) in the wavelength range
115-195 nm showed a doubling of the ultraviolet continuum, a 70-percent
increase in the Ly-alpha 121.6-nm line and a 160-percent increase
in the C IV 154.9-nm line with respect to the observations in early
1988.  The variations in these broad lines are centered at a
velocity of approximately 2000 km/s, blueshifted with respect to the
systemic velocity as indicated by the narrow emission lines.  For the
variable part of the lines, the line ratio C IV/Ly-alpha = 1.3 (versus
the normal value of 0.55 in 1988), suggesting a non-standard excitation
mechanism, possibly of collisional origin.  The central radio source
in 3C 390.3 also shows superluminal motion on a size scale similar to
the outer parts of the nuclear emission line region (approximately 10
ly; cf. Clavel and Wamsteker 1987, Ap.J. 320, L9, and Alef et al.
1988, A.Ap. 192, 53).  This might supply the first opportunity to observe
the relation between the superluminal structures and the broad-line
gas in an active galactic nucleus.  Observations with IUE will be
continued and those at other wavelengths are desirable."

     P. Schmeer, Bischmisheim, West Germany, reports that this
object is again in outburst (cf. IAUC 4526), as indicated
by the following visual magnitude estimates:  1988 Nov. 5.10 UT,
13.5; 1989 Mar. 27.95, [13.7; 28.89, 12.2, 28.96, 12.3.  E. Waagen,
AAVSO, notes that CY UMa is possibly a SU UMa-type dwarf nova;
high-speed photometric observations are strongly recommended, to
search for small-amplitude periodic oscillations to determine whether
or not CY UMa is a member of this class.  Previous supermaxima
occurred on 1988 Jan. 6 and 1988 Oct. 29.

     Further visual magnitude estimates (cf. IAUC 4755):  Mar. 9.96
UT, 13.8 (D. Rodriguez, Madrid, Spain); 10.92, 13.7 (M. Verdenet,
Bourbon-Lancy, France); 11.3, 13.7 (S. H. Lucas, Midlothian, IL);
11.90, 13.8 (J. D. Shanklin, Cambridge, England); 12.86, 14.1 (J.
Ripero, Madrid, Spain); 14.3, 14.2 (D. Patchick, Culver City, CA);
15.45, 14.0 (A. Hale, Las Cruces, NM); 26.18, 14.4 (Hale);
28.91, 15.0 (A. Boattini, Piazzano, Italy).

1989 March 29                  (4763)             Daniel W. E. Green

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