VHE Gamma-ray Observation of Crab Nebula with HAGAR Telescope Array

Abstract

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) $\times 10^{-10}$ 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.

arXiv commentAccepted for publication in experimental astronomy

References in corpus (15)

• Observations of the Crab Nebula with H.E.S.S
• The Evolution and Structure of Pulsar Wind Nebulae
• Gamma-ray flares from the Crab Nebula
• Discovery of Powerful Gamma-Ray Flares from the Crab Nebula
• Measurement of the Crab Nebula spectrum over three decades in energy with the MAGIC telescopes
• Crab: the standard X-ray candle with all (modern) X-ray satellites
• Multiwavelength study of TeV Blazar Mrk421 during giant flare
• Long-term study of Mkn 421 with the HAGAR Array of Telescopes
• Crab Nebula: five-year observation with ARGO-YBJ
• A search for enhanced very high energy gamma-ray emission from the March 2013 Crab Nebula flare
• Multi-frequency, Multi-Epoch Study of Mrk 501: Hints for a two-component nature of the emission
• Six years of VERITAS observations of the Crab Nebula
• Observations of the Crab Nebula with H.E.S.S. Phase II
• Angular Resolution of the Pachmarhi Array of Cerenkov Telescopes
• Study of the Crab Nebula TeV emission variability during five years with ARGO-YBJ

Cited by in corpus (2)

• The development of ground-based Gamma-ray astronomy: a historical overview of the pioneering experiments
• Technological Novelties of Ground-Based Very High Energy Gamma-Ray Astrophysics with the Imaging Atmospheric Cherenkov Telescopes