The high-energy view of the broad-line radio galaxy 3C 111

Abstract

We present the analysis of Suzaku and XMM–Newton observations of the broad‐line radio galaxy (BLRG) 3C 111. Its high‐energy emission shows variability, a harder continuum with respect to the radio‐quiet active galactic nucleus population, and weak reflection features. Suzaku found the source in a minimum flux level; a comparison with the XMM–Newton data implies an increase of a factor of 2.5 in the 0.5–10 keV flux, in the 6 months separating the two observations. The iron K complex is detected in both data sets, with rather low equivalent width(s). The intensity of the iron K complex does not respond to the change in continuum flux. An ultrafast, high‐ionization outflowing gas is clearly detected in the Suzaku/X‐ray Imaging Spectrometer data; the absorber is most likely unstable. Indeed, during the XMM–Newton observation, which was 6 months after, the absorber was not detected. No clear rollover in the hard X‐ray emission is detected, probably due to the emergence of the jet as a dominant component in the hard X‐ray band, as suggested by the detection above ∼100 keV with the GSO onboard Suzaku, although the present data do not allow us to firmly constrain the relative contribution of the different components. The fluxes observed by the γ‐ray satellites CGRO and Fermi would be compatible with the putative jet component if peaking at energies E∼ 100 MeV. In the X‐ray band, the jet contribution to the continuum starts to be significant only above 10 keV. If the detection of the jet component in 3C 111 is confirmed, then its relative importance in the X‐ray energy band could explain the different observed properties in the high‐energy emission of BLRGs, which are otherwise similar in their other multiwavelength properties. Comparison between X‐ray and γ‐ray data taken at different epochs suggests that the strong variability observed for 3C 111 is probably driven by a change in the primary continuum.

The nature of the multi-wavelength emission of 3C 111

“…Our results are consistent with an upper limit reported by Dadina (2007), as well as with the constraints obtained by Molina et al (2009) and Ballo et al (2011). The latter also reported a significantly lower result, R = 0.19 +0.05 −0.04 , when using only soft X-ray data between 0.4 keV and 10 keV.…”

“…Dadina (2007) found a lower limit of E cut ≥ 82 keV using BeppoSAX data and Ballo et al (2011) derived a similar lower limit to the cut-off of E cut ≥ 75 keV, using data from XMM-Newton and Suzaku/XIS and PIN. Molina et al (2009), using XMM-Newton, Swift, and INTEGRAL data, constrained the cut-off energy to be E cut = 126 +193 −50 keV.…”

“…Using Suzaku/XIS data of three different observations taken two years later, Tombesi et al (2011) found a smaller EW of between EW > 33 eV and EW > 40 eV. Similarly, Ballo et al (2011) used XMM-Newton data to fit the 0.4-10 keV spectrum and found an EW = 38 +11 −9 eV. 3C 111 has been detected in γ-rays by CGRO/EGRET (Hartman et al 1999;Sguera et al 2005;Hartman et al 2008), and was included in the first Fermi/LAT catalogue (Abdo et al 2010a).…”

“…An upper limit of R ≤ 2.25 was found by Dadina (2007) using BeppoSAX data and constraints of R = 0.9 ± 0.6 were derived by Molina et al (2009) and R = 0.35 ± 0.06 by Ballo et al (2011) using Suzaku/XIS and PIN data. Ballo et al (2011) used XMM-Newton data to find the reflection in the energy range 0.4-10 keV to be R = 0.19 +0.05 −0.04 . Rivers et al (2011) did not detect a reflection component, using RXTE data between 3 keV and > ∼ 100 keV.…”

The Complex Circumnuclear Environment of the Broad-Line Radio Galaxy 3c 390.3 Revealed by Chandra Hetg

“…The detection of WAs was reported in 3C382, 3C445, 3C390.3, and 4C+74.26 (Ballantyne 2005;Reeves et al 2009Reeves et al , 2010Torresi et al 2010Torresi et al , 2012. Moreover, UFOs have been reported in 3C111, 3C120, 3C390.3, 3C445, 4C +74.26, and Cygnus A (Tombesi et al 2010bBallo et al 2011;Braito et al 2011;Gofford et al 2013Gofford et al , 2015Reynolds et al 2015). A recent X-ray study of a sample of 26 radio galaxies reported that the frequency of UFOs is likely in the interval f; 50% ± 20% .…”