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Since galactic cosmic rays are believed to be created in supernova
remnants (SNRs), SNRs are expected to be a source of
high energy gamma rays through the decay of neutral pions
produced by {\it p-p} colitions. The characteristics of cosmic rays
such as the maximum accelerated energy, spectral index and total
energy SNRs can be probed by their gamma ray emission.
Since the resultant gamma ray spectrum is flatter than that of the
galactic background reflecting the difference of cosmic ray
spectra in SNRs and in the Galaxy, SNRs are likely to be observed
by gamma rays at higher energies.
We have searched for emission of 10 TeV gamma rays from the directions
of 59 SNRs located in the declination band -8.7° and 64.3°,
using the data taken by the Tibet Air Shower in the period
from June 1990 through Octorber of 1993.
DC significances of excess events to the background are examined on
each source to search for evidence of gamma ray emissions.
No obvious DC excess is found from these sources.
Nevertheless, when all SNRs are considered as single candidate
direction, we obtained a significance of 3.59σ which corresponds
to probability 1.65 × 10-4, and integral flux
of 1.46 ± 0.39 - 0.29 × 10-13 cm-2s-1.
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