Vk. Senecha et al., COUNTS-EXCESS FROM AN ATMOSPHERIC CERENKOV TELESCOPE IN THE GENERAL DIRECTION OF THE PULSAR PSR-0355+54, Astronomy and astrophysics, 302(1), 1995, pp. 133-136
We present here results based on observations carried out from 1989 No
vember 20-December 03, using one 3-mirror bank of the Gulmarg gamma-ra
y telescope in the on-off mode. The on-source region, comprising a 4 d
egrees diameter angular-cell centered on alpha = 03(h)54(m) and delta
= +55 degrees, included the direction of the pulsar PSR 0355+54, from
which a significant pulsed signal, with a period of similar to 156.38
ms, has been reported by the Pachmarhi group. While no pulsar-related
periodic modulation is found in the 1989 Gulmarg data, there is a sugg
estion about the presence of similar to 4.1 sigma d.c. excess from the
on-source region. Taken at its face value, this excess can be interpr
eted as a steady gamma-ray signal with an integral flux of similar to
(4.5 +/- 0.8) 10(-11) photons cm(-2) s(-1) at energies beyond 4 TeV. N
o other TeV gamma-ray experiment, so far, has reported the detection o
f such a signal from this region. We propose here that this signal may
possibly be due to a hitherto-unknown source lying in the overall on-
source region.