Testing the AGN Paradigm, Part I: a generic SED for Seyfert 1 galaxies

TL;DR

This study constructs a generic spectral energy distribution (SED) for Seyfert 1 galaxies to test the AGN unification paradigm, revealing insights into torus structure, accretion processes, and AGN wind evolution.

Contribution

It provides the first generic SED for Seyfert 1 galaxies using X-CIGALE, supporting the unification model and uncovering new details about accretion and wind dynamics.

Findings

Supports the existence of a torus in Seyfert 1 galaxies.

Reveals a link between accretion events and AGN wind initiation.

Suggests evolution of some Seyfert 1 subtypes into windless AGN.

Abstract

This article presents the first part of a study aimed at testing the unification paradigm for AGN (UPAGN) using the SED reconstruction code X-CIGALE. Our method consists in obtaining a generic SED for a large sample of Seyfert 1 (Sy1; part 1), then applying this SED to Seyfert 2 (Sy2; Part~II), expecting that the only difference will be the line-of-sight (LOS) angle, $i$, relative to the polar axis of the torus of gas and dust obscuring the broad line regions (BLRs). Our sample is composed of 3,896 Type 1, Sy1 at low redshifts, $ z<0.4$, separated into four spectral subgroups depending on the presence or absence in their spectra of narrow emission lines, Sy1N/Sy1B, and AGN wind, Sy1Bw and Sy1Nw. The generic SED produced by X-CIGALE applies to 90\% of the Sy1 in our sample. It includes a clumpy torus with an AGN engine seen face-on ($i \sim 10^\circ \pm 5^\circ$). Our analysis not only supports the existence of a torus in Sy1, in good agreement with UPAGN, but also reveals new facts about the accretion of matter and AGN wind: 1- a sudden accretion of matter from the BLR to the accretion disk triggered the wind, 2- matter from the wind replenishes the torus, consistent with a gradual formation of this structure by recurrent AGN winds, and 3- Sy1Bw and Sy1Nw eventually evolve as AGN without wind, leaving behind a torus as evidence of a higher AGN activity in their past.