Discovery of very high energy $gamma$-rays from markarian 180 triggered by an optical outburst
Journal
The Astrophysical Journal Letters 648, L105, 2006
ticlealbert2006discovery, title=Discovery of very high energy $gamma$-rays from markarian 180 triggered by an optical outburst, author=Albert, J and Aliu, E and Anderhub, H and Antoranz, P and Armada, A and Asensio, M and Baixeras, C and Barrio, JA and Ba
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 $\gamma$-ray emission was detected with a significance of 5.5 $\sigma$. 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.