Central Bureau for Astronomical Telegrams
IAUC 4507: 1987d1; PSR 1951+32
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Read IAUC 4508
Circular No. 4507
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 617-495-7244/7440/7444
COMET ICHIMURA (1987d1)
Continuation to the ephemeris on IAUC 4504:
1987 ET R.A. (1950) Decl. Delta r m1
Dec. 13 21 53.77 -60 39.5 0.370 0.861 5.7
14 21 32.96 -60 03.9
15 21 14.10 -59 19.6 0.396 0.815 5.6
16 20 57.10 -58 28.8
17 20 41.80 -57 33.4 0.424 0.768 5.5
18 20 28.05 -56 34.9
19 20 15.65 -55 34.3 0.454 0.719 5.4
20 20 04.45 -54 32.3
21 19 54.28 -53 29.6 0.487 0.670 5.2
22 19 45.02 -52 26.4
23 19 36.55 -51 22.9 0.521 0.620 5.0
24 19 28.77 -50 19.2
25 19 21.59 -49 15.3 0.558 0.568 4.8
PSR 1951+32
N. d'Amico, Universita di Palermo; K. Bennett and J. Clear
ESA Space Science Department, Noordwijk; and R. Buccheri and B.
Sacco, Laboratorio di Fisica Cosmica, Palermo, report: "Li, Li, Ma
and Wu (IAUC 4492) have reported the detection of pulsed high-
energy gamma-ray emission from PSR 1951+32. Their analysis was
performed using observation No. 26 from the public COS-B database.
During similar contemporaneous searches for pulsed emission, we
found a 9.5-sigma effect for observation period 4, corresponding to a
probability of less than 1 percent when the number of trials is
taken into account. In this analysis we used the established
event-selection criteria of Mayer-Hasselwander and an energy-
dependent selection cone about the pulsar position that maximizes
the signal-to-noise for the COS-B point-spread function (Buccheri
et al.). Our analyis of observation period 26 does not show the
signal of Li et al. at the quoted significance level. Furthermore,
we were not able to reproduce the number of events (378)
they quoted, and their period is not compatible with that found by
us for observation period 4. We therefore urge that these
discrepancies be investigated and resolved before making a firm statement
on the existence of pulsed gamma-ray emission from PSR 1951+32."
1987 December 3 (4507) Brian G. Marsden
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