Circular No. 3644 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 617-864-5758 1981 VA J. Williams, California Institute of Technology, reports that E. Helin and S. Dunbar have discovered a fast-moving asteroidal object with the l.2-m Schmidt telescope at Palomar, as follows: 1981 UT R. A. (1950) Decl. Mag. Nov. 4.31979 2 55.2 +56 38 16.5 5.40104 2 51.0 +54 20 5.48438 2 50.8 +54 10 PSR 0833-45 P. M. McCulloch, P. A. Hamilton, and G. W. R. Royle, University of Tasmania; and R. N. Manchester, Division of Radiophysics, CSIRO, telex: "We observed an abrupt decrease in the period of the Vela pulsar, PSR 0833-45, at Oct. 11d01h40m UT. The fractional change at that time in pulse frequency was 1.144 (+/- 0.003) x 10**-6 and in frequency derivative was 0.018 +/- 0.003. These results were derived from 2295-MHz observations made at ~ weekly intervals at the NASA Deep Space Station, Tidbinbilla, from July 9 to Oct. 14, and from daily 635-MHz observations of 5-hr duration at Hobart from Oct. 8-14. As the actual jump was not observed, its epoch was computed by assuming no discontinuity in pulse phase at time of jump. Though smaller, this jump is similar to those observed previously." Q0957+561A, B M. V. Gorenstein, I. I. Shapiro, A. F. F. Rogers and N. L. Cohen, Massachusetts Institute of Technology and Haystack Observatory, write: "We have detected a third compact radio component smaller than 0".003 in extent from 13-cm VLBI observations of the gravitational 'lens' system Q0957+561. The component, 0".181 east and 1".029 north of the B quasar (equinox 1950.0, +/- 0".001), is near or at the center of the elliptical galaxy thought to be mainly responsible for the multiple imaging. This detection utilized the Mark III VLBI system and the large antennas at Effelsberg, Goldstone and Madrid on Mar. 15-16. Data from the Goldstone-Madrid baseline (0".0035 fringe-spacing) and from the Bonn-Madrid baseline (0".020 fringe-spacing) yielded flux densities of 600 +/- 90 and 1700 +/- 150 uJy, respectively. The component could be either the radio core of the galaxy, another image of the quasar or some combination." 1981 November 6 (3644) Daniel W. E. Green
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