Subrelativistic Jets from Black Hole Accretion Vortices. I. The Extreme‐Ultraviolet and X‐Ray Emission from Radio‐quiet Quasars

Abstract

This article and its companion describe a theory of quasars that differentiates radio-loud quasars from radio-quiet quasars by the physical structures extant in the accretion vortices above the poles of a supermassive, rapidly rotating black hole. Quasars are manifestly radio loud as a consequence of large-scale magnetic flux threading these funnels and relativistic magnetic winds of plasma that propagate outward (magnetic wind models of radio-loud quasars exist in the literature). Radio-quiet quasars are devoid of this large-scale magnetic flux, and radiation pressure in the funnel drives hypersonic, underexpanded, subrelativistic jets. These jets are relatively feeble compared to the radiation-driven relativistic jets from the funnels of superluminous accretion disks that were popular in the theoretical literature of the 1980s. The primary emphases of this article are the near-field dynamics and the observational implications of the radiation-driven jets from these vortices conjectured to exist in radio-quiet quasars. The physical state of the ejecta is governed by the force of gravity, the initiating continuum radiation pressure, and the line-driving forces from ultraviolet accretion disk radiation. These hypersonic jets form a bipolar broad absorption line region (BALR) with a small covering factor dictated by the collimation of the jets. Consequently, radio-quiet quasars have broad absorption lines in the UV region of their spectra if the line of sight passes through a jet. Radio-loud quasars do not have BALRs in this model. It is demonstrated in the companion article that absorbing columns with a range of outflow velocities from ≈ 0 km s-1 to more than 35,000 km s-1 result in these putative jets. In this article it is shown that the frictional and compressional heating in the turbulent boundary layer between the base of the jet and the funnel walls creates a hot corona above the innermost regions of the disk. The corona cools by Compton-scattering disk UV radiation, creating the far-UV and soft X-ray excess that radio-quiet quasars have relative to radio-loud quasars as found in composite spectra of the Hubble Space Telescope (HST) and ROSAT archives, respectively. Furthermore, Compton cooling of the hot outer regions of the corona creates the flat spectral energy distribution of hard X-rays observed in radio-quiet quasars. By the geometry of an X-ray source collaring the base of the jet, if the line of sight passes through the jet (a BAL quasar), X-ray emission is obscured. Thus, soft X-ray emission is suppressed in BAL quasars relative to the rest of the radio-quiet population in the model as observed. Seyfert galaxies do not have disks that are luminous to drive winds from the vortex and hence do not have BALRs in the model consistent with IUE searches.