The broad-line radio galaxy 3C111, characterized by a Fanaroff-Riley II (FRII) radio morphology, is one of the sources of the misaligned active galactic nucleus sample, consisting of radio galaxies and steep spectrum radio quasars, recently detected by the Fermi Large Area Telescope (LAT). Our analysis of the 24 month γ-ray light curve shows that 3C111 was only occasionally detected at high energies. It was bright at the end of 2008 and faint, below the Fermi-LAT sensitivity threshold, for the rest of the time. A multifrequency campaign of 3C111, ongoing in the same period, revealed an increase of the millimeter, optical, and X-ray fluxes in 2008 September-November, interpreted by Chatterjee etal. as due to the passage of a superluminal knot through the jet core. The temporal coincidence of the millimeter-optical-X-ray outburst with the GeV activity suggests a cospatiality of the events, allowing, for the first time, the localization of the γ-ray dissipative zone in an FRII jet. We argue that the GeV photons of 3C111 are produced in a compact region confined within 0.1 pc and at a distance of about 0.3 pc from the black hole. © 2012. The American Astronomical Society. All rights reserved..
Grandi, P., Torresi, E., Stanghellini, C. (2012). The γ-ray emission region in the Fanaroff-Riley II radio galaxy 3C111. THE ASTROPHYSICAL JOURNAL LETTERS, 751(1), 751-755 [10.1088/2041-8205/751/1/L3].
The γ-ray emission region in the Fanaroff-Riley II radio galaxy 3C111
GRANDI, PAOLA;TORRESI, ELEONORA;
2012
Abstract
The broad-line radio galaxy 3C111, characterized by a Fanaroff-Riley II (FRII) radio morphology, is one of the sources of the misaligned active galactic nucleus sample, consisting of radio galaxies and steep spectrum radio quasars, recently detected by the Fermi Large Area Telescope (LAT). Our analysis of the 24 month γ-ray light curve shows that 3C111 was only occasionally detected at high energies. It was bright at the end of 2008 and faint, below the Fermi-LAT sensitivity threshold, for the rest of the time. A multifrequency campaign of 3C111, ongoing in the same period, revealed an increase of the millimeter, optical, and X-ray fluxes in 2008 September-November, interpreted by Chatterjee etal. as due to the passage of a superluminal knot through the jet core. The temporal coincidence of the millimeter-optical-X-ray outburst with the GeV activity suggests a cospatiality of the events, allowing, for the first time, the localization of the γ-ray dissipative zone in an FRII jet. We argue that the GeV photons of 3C111 are produced in a compact region confined within 0.1 pc and at a distance of about 0.3 pc from the black hole. © 2012. The American Astronomical Society. All rights reserved..I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
