Circular No. 5485 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 or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN PSR 1706-44 The Compton Observatory EGRET Pulsar Team (D. A. Kniffen, Hampden-Sydney College; D. L. Bertsch, C. E. Fichtel, R. C. Hartman, S. D. Hunter, P. W. Kwok, J. R. Mattox, H. I. Nel, P. Sreekumar and D. J. Thompson, NASA Goddard Space Flight Center; J. M. Fierro, Y. C. Lin, P. F. Michelson and P. L. Nolan, Stanford University; E. Schneid, Grumman Aerospace Corporation; G. Kanbach, H. A. Mayer-Hasselwander, C. von Montigny, K. Pinkau, H. Rothermel and M. Sommer, Max-Planck- Institut fur Extraterrestrische Physik; S. Johnston and R. Manchester, CSIRO; V. Kaspi and J. Taylor, Princeton University; A. G. Lyne, University of Manchester, Jodrell Bank) reports a significant detection of pulsed gamma radiation above 100 MeV from PSR 1706-44, at the radio period of 102 ms, in an observation made during 1991 July 12-27. The gamma-ray source was identified by COS-B as 2CG 342-02. Unlike the Crab and Vela pulsars, the high-energy gamma radiation from PSR 1706-44 exhibits a single broad pulse. EGRET is now viewing this pulsar again and will do so until Apr. 6. NGC 4051 L. K. Hunt, CAISMI-CNR, Florence; G. Calamai, E. Giannuzzo and M. Salvati, Arcetri Observatory; and G. Del Zanna, F. Mannucci, A. Righini and R. Stanga, Department of Astronomy, University of Florence, e-mail: "According to measurements with the Italian National Infrared telescope TIRGO, the Seyfert 1 galaxy NGC 4051 is undergoing an outburst in the near-infrared on a timescale of a few months. Observations of galaxy-plus-nucleus in a 14" aperture gave the following K magnitudes: 1991 Apr. 15, 9.90 +/- 0.02; 1992 Jan. 6, 9.76 +/- 0.02; Mar. 6, 9.59 +/- 0.03. If the galaxy's contribution to the 1991 flux is 0.6, the brightening of the nucleus in Jan. and Mar. 1992 amounts to 35 and 80 percent, respectively. At the Loiano station of the Bologna Observatory the galaxy-plus-nucleus B magnitude, obtained from a CCD image by summing within a 6" aperture, was 14.1 +/- 0.1 on Mar. 17. This observation, and the maximum K magnitude measured on Mar. 6, are consistent (within the uncertainties) with the 1988 observations of Done et al. (1990, MNRAS 243, 713). In view of the relevance of the phenomenon to the modeling of the infrared emission of active galactic nuclei (direct versus dust re-radiation), monitoring of the outburst is highly recommended, especially at the wavelengths dominated by the so-called big blue bump (B, U, ultraviolet)." 1992 March 31 (5485) Brian G. Marsden
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