12-20 July 2017
BEXCO
Asia/Seoul timezone
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Contribution

BEXCO - Room E(106/107)

[GA030] Spectacular Flares of the Radio Galaxy NGC 1275 measured with MAGIC

Speakers

  • Dorit GLAWION

Primary authors

  • Dorit GLAWION (Landessternwarte, Universitaet Heidelberg, Germany)

Co-authors

Description

We report on the detection of flaring activity from the prominent Fanaroff-Riley I radio galaxy NGC 1275 located in the Perseus cluster of galaxies in the very-high-energy gamma-ray band. The observations were performed with the MAGIC telescopes between 2016 and 2017 over several months. During this time period, the mean flux above 100 GeV was measured to be ten times brighter than during previous measurements. The night-by-night light curve above 100 GeV shows several peaks indicating flux-doubling time-scales of shorter than one day much smaller than the monthly time-scale previously detected by MAGIC. The brightest flux, observed around New Year, reached 1.5 times the flux from the Crab Nebula, i.e. about hundred times brighter than the average flux of the previous years. The spectral energy distribution measured up to >1 TeV shows a curved shape and differs from previous measurements. The angle between the jet-axis and the line-of sight of NGC 1275 was previously found to be 30-55 degree in the radio band excluding strong Doppler boosting for this object. The fast TeV flux variability and the spectral behaviour observed from a non-blazar object challenge current standard theoretical models and therefore, provide new and fascinating insights into the gamma-ray production and emission mechanism of active galactic nuclei. We will present the observational results and discuss possible physical processes responsible for the flaring events.