Jul 12 – 23, 2021
Europe/Berlin timezone

Extreme blazars under the eyes of MAGIC

Jul 13, 2021, 6:00 PM
1h 30m


Talk GAI | Gamma Ray Indirect Discussion


Axel Arbet-Engels (ETH Zürich, Switzerland)


Extreme high-frequency-peaked BL Lac objects (EHBLs) are the most energetic persistent sources in the universe. This contribution reports on long-term observing campaigns of tens of EHBLs that have been organized by the MAGIC collaboration to enlarge their population at VHE and understand the origin of their extreme properies. EHBLs are characterized by a spectral energy distribution (SED) featuring a synchrotron peak energy above 1 keV. Several EHBLs display a hard spectral index at very high energies (VHE; E>100 GeV), suggesting a gamma-ray SED component peaking significantly above 1 TeV. Such extreme properties are challenging current standard emission and acceleration mechanisms. Recent studies have also unveiled intriguing disparities in the temporal characteristics of EHBLs. Some sources seem to display a persistent EHBL behaviour, while others belong to the EHBL family only temporarily.
We will focus on the recent results of the first hard-TeV EHBL catalog. The MAGIC observations are accompanied by an extensive multi-wavelength coverage to obtain an optimal determination of the SED. This allow us to investigate leptonic and hadronic scenarios for the emission. We will also present the recent detection of the EHBL 1RXS0812.0+0237 in the VHE band by MAGIC. Finally, we will discuss a broad multi-wavelength campaign on the BL Lac type object 1ES2344+514, which showed intermittent EHBL characteristics in August 2016.


AGN; gamma-ray; non-thermal radiation ; modelling; BL Lacertae objects; Extreme blazars

Collaboration MAGIC
other Collaboration FACT
Subcategory Experimental Results

Primary author

Axel Arbet-Engels (ETH Zürich, Switzerland)


Cornelia Arcaro (INAF, Roma, Italy) Katsuaki Asano (ICRR, The University of Tokyo, Japan ) Josefa Becerra González (Instituto de Astrofisica de Canarias, La Laguna, Spain) Giacomo Bonnoli (Università di Siena and INFN Pisa, Italy) Matteo Cerruti (Université de Paris, Astroparticule et Cosmologie (APC), France) Filippo D'Ammando (NAF - Istituto di Radioastronomia, Bologna, Italy) Paolo Da Vela (University of Innsbruck, Austria) Daniela Dorner (Universität Würzburg, Germany) Vandad Fallah Ramazani (Ruhr-Universität Bochum, Germany) Luca Foffano (University of Geneva, Switzerland) Jenni Jormanainen (Finnish Centre for Astronomy with ESO, University of Turku, Finland) Marina Manganaro (University of Rijeka, Croatia) Dr Elisa Prandini (Università di Padova and INFN, Italy) Fabrizio Tavecchio (INAF, Roma, Italy) Sofia Ventura (Università di Siena and INFN Pisa, Italy) for the MAGIC and FACT Collaborations

Presentation materials