VHE Gamma-ray Observation of Crab Nebula with HAGAR Telescope Array. (arXiv:1902.01081v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Singh_B/0/1/0/all/0/1">B.B. Singh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Britto_R/0/1/0/all/0/1">R.J. Britto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chitnis_V/0/1/0/all/0/1">V.R. Chitnis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shukla_A/0/1/0/all/0/1">A. Shukla</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Saha_L/0/1/0/all/0/1">L. Saha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sinha_A/0/1/0/all/0/1">A. Sinha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Acharya_B/0/1/0/all/0/1">B.S. Acharya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vishwanath_P/0/1/0/all/0/1">P.R. Vishwanath</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Anupama_G/0/1/0/all/0/1">G.C. Anupama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bhattacharjee_P/0/1/0/all/0/1">P. Bhattacharjee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gothe_K/0/1/0/all/0/1">K.S. Gothe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nagesh_B/0/1/0/all/0/1">B.K. Nagesh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Prabhu_T/0/1/0/all/0/1">T.P. Prabhu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rao_S/0/1/0/all/0/1">S.K Rao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Srinivasan_R/0/1/0/all/0/1">R. Srinivasan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Upadhya_S/0/1/0/all/0/1">S.S. Upadhya</a>
HAGAR is a system of seven Non-imaging Atmospheric Cherenkov Telescopes
located at Hanle in the Ladakh region of the Indian Himalayas at an altitude of
4270 meters {it amsl}. Since 2008, we have observed the Crab Nebula to assess
the performance of the HAGAR telescopes. We describe the analysis technique for
the estimation of $gamma$-ray signal amidst cosmic ray background. The
consolidated results spanning nine years of the Crab nebula observations show
long term performance of the HAGAR telescopes. Based on about 219 hours of
data, we report the detection of $gamma$-rays from the Crab Nebula at a
significance level of about 20$sigma$, corresponding to a time averaged flux
of (1.64$pm$0.09) $times10^{-10}$ photons cm$^{-2}$ sec$^{-1}$ above 230 GeV.
Also, we perform a detailed study of possible systematic effects in our
analysis method on data taken with the HAGAR telescopes.
HAGAR is a system of seven Non-imaging Atmospheric Cherenkov Telescopes
located at Hanle in the Ladakh region of the Indian Himalayas at an altitude of
4270 meters {it amsl}. Since 2008, we have observed the Crab Nebula to assess
the performance of the HAGAR telescopes. We describe the analysis technique for
the estimation of $gamma$-ray signal amidst cosmic ray background. The
consolidated results spanning nine years of the Crab nebula observations show
long term performance of the HAGAR telescopes. Based on about 219 hours of
data, we report the detection of $gamma$-rays from the Crab Nebula at a
significance level of about 20$sigma$, corresponding to a time averaged flux
of (1.64$pm$0.09) $times10^{-10}$ photons cm$^{-2}$ sec$^{-1}$ above 230 GeV.
Also, we perform a detailed study of possible systematic effects in our
analysis method on data taken with the HAGAR telescopes.
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