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IAUC 5612: N Cyg 1992; GEMINGA

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                                                  Circular No. 5612
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

     C. E. Woodward, University of Wyoming; D. Van Buren, California
Institute of Technology; P. Hofner, University of Wisconsin,
Madison; and M. A. Greenhouse, National Air and Space Museum,
Smithsonian Institution, write:  "We have obtained near-infrared
spectra of N Cyg 1992 (spectral range 3.590-3.790 microns, resolution
0.0033 micron) using the 2.1-m telescope (+ CRSP) at Kitt Peak
National Observatory on Sept. 9.29 UT.  Prominent in the spectra of
the nova is the coronal line [Al VI] (observed wavelength 3.6480
+/- 0.0014 microns) and the hydrogen recombination line Pf-gamma
(observed wavelength 3.7384 +/- 0.0015 microns).  The discovery of
the [Al VI] line at this epoch suggests that the nova has entered
into the coronal line phase of its evolution about 200 days after
outburst.  This evolutionary timescale is comparable to that seen
in other novae that have exhibited coronal line emission such as
V1500 Cyg and QU Vul.  Preliminary analysis of the N Cyg 1992
spectra yields the following line flux estimates (x 10E-19 W cmE-2):
[Al VI] = 1.10 +/- 0.13; Pf-gamma = 1.18 +/- 0.25."
     R. Monella, Covo, Italy, telexes the following photometry
(comparison star BD +52 2734):  Sept. 1.888 UT, V = 9.27, B-V =
+0.18; 3.917, 9.29, +0.18; 5.925, 9.28, +0.16; 6.968, 9.30, +0.17.

     P. R. Vishwanath, G. P. Satyanarayana, P. V. Ramanamurthy, and
P. N. Bhat, Tata Institute of Fundamental Research, Bombay, report:
"We have reanalyzed the TeV gamma-ray data taken on Geminga with
the atmospheric Cerenkov Technique at Ootacamund during 1984 Dec.-
1985 Feb. (cf. Bhat et al. 1987, A.Ap. 171, 84).  A total of 28 hr
of data at an energy threshold of 0.8 TeV was analysed for the
presence of the 237-ms period seen by the Rosat, EGRET, and COS-B
telescopes. The phase analysis done with the ephemeris of Hermsen et
al. (IAUC 5541) revealed the presence of two peaks separated by 0.5
in phase.  The probability that the two peaks are due to chance is
0.1 percent.  The two peaks coincide in absolute phase with the
position of the two peaks in COS-B data (Hermsen, private communication).
The flux of gamma-rays is calculated to be (2.1 +/- 0.8) x
10E-11 photon cmE-2 sE-1 at an energy threshold of 0.8 TeV.   A
detailed paper for publication is under preparation."

1992 September 14              (5612)            Daniel W. E. Green

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