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IAUC 5485: PSR 1706-44; NGC 4051

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                                                  Circular No. 5485
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

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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