Signatures of the Disk–Jet Coupling in the Broad-line Radio Quasar 4C+74.26

Abstract

Here we explore the disk-jet connection in the broad-line radio quasar 4C+74.26, utilizing the results of the multiwavelength monitoring of the source. The target is unique in that its radiative output at radio wavelengths is dominated by a moderately-beamed nuclear jet, at optical frequencies by the accretion disk, and in the hard X-ray range by the disk corona. Our analysis reveals a correlation (local and global significance of 96% and 98%, respectively) between the optical and radio bands, with the disk lagging behind the jet by 250 ± 42 days. We discuss the possible explanation for this, speculating that the observed disk and the jet flux changes are generated by magnetic fluctuations originating within the innermost parts of a truncated disk, and that the lag is related to a delayed radiative response of the disk when compared with the propagation timescale of magnetic perturbations along relativistic outflow. This scenario is supported by the re-analysis of the NuSTAR data, modelled in terms of a relativistic reflection from the disk illuminated by the coronal emission, which returns the inner disk radius R in /R ISCO = 35 +40 −16 . We discuss the global energetics in the system, arguing that while the accretion proceeds at the Eddington rate, with the accretion-related bolometric luminosity L bol ∼ 9 × 10 46 erg s −1 ∼ 0.2L Edd , the jet total kinetic energy L j ∼ 4 × 10 44 erg s −1 , inferred from the dynamical modelling of the giant radio lobes in the source, constitutes only a small fraction of the available accretion power.

Detection of Periodic Radio Signal from the Blazar J1043+2408

“…However, the probability of observing such a close (milliparsec) system of binary SMBH might be too small [see 52]. But on the other hand, in the case of strong disk-jet connection [e.g., in 57] (see also [11]), the periodic modulations induced due to binary SMBH system could propagate down the jet affecting the Doppler boosted emission. In such case, true periodic timescales at the BH could be longer than the observed one due to relativistic effects, i.e.…”

“…After we have employed three different methods to detect periodicity in the light curve, it should be pointed out that, in general, the statistical properties of blazar light curves can be characterized as red-noise processes that can potentially mimic a transient periodic behavior, especially in the low-frequency domain [see 11,14,42, for the discussion]. In addition, spurious peaks might arise owing to other sampling effects including discrete sampling, finite observation period and uneven sampling of the light curve.…”

Broadband X-Ray Constraints on the Accreting Black Hole in Quasar 4C 74.26

“…Hasenkopf et al (2002) reported a broad only line for the same ASCA, and also BeppoSAX data. In more recent work, a broad line was reported by Ballantyne & Fabian (2005); Ballantyne (2005); Larsson et al (2008);Patrick et al (2012);Tombesi et al (2014); Gofford et al (2013); Di Gesu & Costantini (2016); Lohfink et al (2017); Bhatta et al (2018). In contrast, Noda et al (2013) reported a narrow line only.…”

“…However, the fit is rather poor (χ 2 ν = 1.3, P null = 3 × 10 −4 ). Modifying the model setup by fixing R out = 1000 r g and disk inclination angle to 45 • (Bhatta et al 2018) only produced a poor best fit, with χ 2 ν = 1.5 and P null = 1 × 10 −8 . Modifying this model setup by relaxing the requirement for uniform emissivity leads to an improved fit (χ 2 ν = 1.2, P null = 0.01) with an inner disk emissivity index of 5 +2 −1 and an outer disk index of 0.8 +0.5 −1.1 for an assumed break radius of 20 r g .…”

“…Patrick et al (2012) and Gofford et al (2013) also reported fitting a narrow line component. Further, four works estimated or assumed SMBH spin values for this and Bhatta et al (2018) assumed a maximally spinning black hole (spin value of 1), Lohfink et al (2017) reported constraining spin values to >0.5. Further details on previous work are given in Appendix A.…”