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Discovery of Very High Energy $γ$-Rays from Markarian~180 Triggered by an Optical Outburst

J. Albert et al.
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Abstract

The high-frequency-peaked BL Lacertae object Markarian~180 (Mrk~180) was observed to have an optical outburst in 2006 March, triggering a Target of Opportunity observation with the MAGIC telescope. The source was observed for 12.4 hr and very high energy $γ$-ray emission was detected with a significance of 5.5 $σ$. An integral flux above 200 GeV of $(2.3\pm0.7)\times10^{-11} {cm}^{-2} {s}^{-1}$ was measured, corresponding to 11% of the Crab Nebula flux. A rather soft spectrum with a photon index of $-3.3\pm0.7$ has been determined. No significant flux variation was found.

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J. Albert et al.. 2006-09-22. Discovery of Very High Energy $γ$-Rays from Markarian~180 Triggered by an Optical Outburst. https://doi.org/10.1086/508020

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