Speaker
Dr
Takashi SAKO
(Institute for Cosmic Ray Research, University of Tokyo)
Description
The Crab Nebula is the standard calibration candle for TeV cosmic
gamma-ray experiments.
None of those experiments has detected gamma rays above 100 TeV from the Crab Nebula,
and the best upper limits have been given by the CASA-MIA experiment.
In the circumstances, it is a common understanding that the energy spectrum of
the Crab Nebula can be reproduced well by a mechanism based on the synchrotron
self-Compton emission of high energy electrons.
The observation of the energy spectrum of the Crab Nebula above 100 TeV
with high sensitivity is important, in order to confirm the leptonic origin of
the TeV gamma-ray emission from the Crab Nebula.
To improve the sensitivity of the Tibet air shower array to TeV cosmic gamma rays,
we are planning to add an underground
10,000 m$^2$ muon detector array to the existing Tibet air shower array.
A small prototype muon detector, 100 m$^2$ in area, was constructed under the Tibet air shower array
in the late fall of 2007.
In this work, we search for continuous gamma-ray emission from the Crab Nebula
above 100 TeV, using the data collected from March 2008 to February 2010
by the Tibet air shower array and the 100 m$^2$ muon detector.
We find that our MC simulation is in good agreement with the experimental data.
No significant excess is found, and the most stringent upper limit is obtained above 140 TeV.
| Registration number following "ICRC2015-I/" | 106 |
|---|---|
| Collaboration | -- not specified -- |
Author
Dr
Takashi SAKO
(Institute for Cosmic Ray Research, University of Tokyo)
Co-author
The Tibet ASgamma COLLABORATION
(The Tibet ASgamma Experiment)
