Fermi Gamma-ray Space Telescope

Long-term MAGIC and multi-wavelength observations on PG 1553+113

E. Prandini
A. Stamerra, U. Barres, S. Covino, P. Da Vela, C. Ferrigno, G. Hughes, E. Lindfors, M. Nievas, S. Paiano, A. Sandrinelli, On. behalf of the MAGIC Collaboration, S. Ciprini, S. Cutini, R. Desiante, D. Gasparrini, F. Longo, For. the Fermi-LAT Collaboration

Abstract:

The Fermi-LAT collaboration recently reported the detection of a ~2-year modulation of the integral flux emitted in both optical and high-energy (HE, 100 MeV<E<100 GeV) gamma rays. Interestingly, one the physical scenarios that can account for such variability pattern is the presence of a supermassive black hole binary in the nucleus of PG 1553+113. PG 1553+113 is a blazar with an uncertain redshift detected at very high energies (VHE; E > 100 GeV) both during high and quiescent flux states. The MAGIC telescopes have observed PG 1553+113 at VHE since 2005. An intense multi-wavelength campaign aimed at unbiased monitoring of the source activity, from radio to VHE gamma rays, started in 2015. The multi-wavelength results from the last ~10 years from radio to VHE gamma rays together with polarization measurements are used to test the periodicity of the source.