Monitoring of bright, nearby Active Galactic Nuclei with the MAGIC telescopes

TL;DR

This paper discusses the MAGIC telescopes' dedicated, unbiased monitoring of nearby AGN to understand their flux variability, spectral changes, and potential periodicity, enhancing knowledge of AGN emission mechanisms.

Contribution

It presents the first long-term, unbiased TeV gamma-ray monitoring program of nearby AGN, providing new insights into their flux states and emission processes.

Findings

Unbiased flux distribution of AGN obtained

Spectral changes correlated with activity levels

Potential periodic behavior identified in lightcurves

Abstract

Observations and detections of Active Galactic Nuclei (AGN) by Cherenkov telescopes are often triggered by information about high flux states in other wavelength bands. To overcome this bias, the VHE gamma-ray telescope MAGIC has conducted dedicated monitoring observations of nearby AGN since 2006. Three well established, TeV-bright blazars were selected to be observed regularly: Mrk 421, Mrk 501, and 1ES1959+650. The goals of these observations are to obtain an unbiased distribution of flux states shedding light on the duty cycle of AGN, to investigate potential spectral changes during periods of different source activity, and to correlate the results with multiwavelength observations. Also clues on a potential periodic behavior of the sources might be drawn from a study of the obtained lightcurves. By testing predictions of theoretical models, like, e.g., the correlation between the TeV flux level and the peak frequency predicted in SSC models, monitoring deepens our knowledge about the acceleration and emission processes in AGN. The status and results of the MAGIC AGN monitoring program will be presented.