Central Bureau for Astronomical Telegrams
IAUC 5316: N Sgr 1991; Poss. gamma-RAY PULSARS 0656+14, 0950+08, 1822-09
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Read IAUC 5317
Circular No. 5316
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
NOVA SAGITTARII 1991
M. Della Valle, European Southern Observatory, reports: "
Spectrograms (range 390-720 nm, resolution about 0.1 nm) of Nova Sgr
1991 (cf. IAUC 5313, 5315) were obtained on Aug. 1.3 and 2.3 UT with
the ESO/Max-Planck-Institut 2.2-m telescope (+ EFOSC) at La Silla.
Analysis of the spectra finds very strong and broad Balmer emission
lines superimposed on a relatively weak continuum. The FWZI width
of H-alpha, H-beta, H-gamma, and H-delta emissions are about 9500,
8000, 9000, and 8500 km/s, respectively. Other prominent features
are visible at 449, 466, 503, 518, and 590 nm. The Balmer emission
lines tend to have a saddle-shaped profile with the redward maximum
stronger than the blue one. The large expansion velocity, the rate
of decline in optical light and the shape of the emission lines
suggest a striking similarity with the outburst of Nova Cyg 1975 (see
Rosino and Tempesti 1977, Sov. Astron. 21, 291)."
S. Prins, Astronomical Institute, University of Amsterdam,
reports the following photometric observations obtained on Aug. 2.4 UT
with the ESO 1-m telescope at La Silla: V = 9.98, B-V = +0.15, U-B
= -0.75, V-R = +1.24, V-I = +1.46.
POSSIBLE gamma-RAY PULSARS 0656+14, 0950+08, 1822-09
Yuqian Ma, Tan Lu, K. N. Yu, and E. C. M. Young, City Polytechnic
of Hong Kong, report: "We reanalyzed the COS-B data to search
for pulsed gamma-ray emissions, and have found evidence for the
existence of lightcurves with characteristic peaks for pulsars
0656+14 and 0950+08 in the range 40-5000 MeV, and for 1822-09 in
the range 300-5000 MeV (the lower energy range was discarded for
improvement of the signal-to-noise ratio for this source, which is
closer to the galactic center). By mapping the relevant high-galactic
latitude COS-B data, a point source feature appears to be at the
position of PSR 0950+08. The following parameters are epoch (MJD),
period (s), and period derivative (x 10E-15): PSR 0656+14,
2443052.3606, 0.384855900, 104.56; PSR 0950+08, 2443635.2495,
0.2530651265, 0.22915; PSR 1822-09, 2442861.9963, 0.7689537620,
83.7; second observation for PSR 1822-09, 2444298.9155, 0.7689537776,
36.6."
1991 August 2 (5316) Daniel W. E. Green
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