Accretion and ejection at work in the Narrow Line Seyfert 1 galaxy 1H 0323+342

A case of intermittent activity?

¹ Department of Physics and Astronomy, University of Padova, vicolo dell’Osservatorio 3, 35122 Padova, Italy
² Brera Astronomical Observatory, National Institute of Astrophysics (INAF), via Bianchi 46, 23807 Merate, Italy

^⋆ Corresponding author.

Received: 18 November 2024
Accepted: 25 March 2025

Abstract

Context. We present a comprehensive investigation into the properties of 1H 0323+342, a prominent jetted narrow-line Seyfert 1 galaxy.

Aims. The primary objective is to understand the interplay between the relativistic jet, the hot corona, and the accretion disk around the supermassive black hole.

Methods. This study spans the years 2006 to 2023, incorporating a rich dataset with 172 Swift observations, including the optical, UV, and X-ray bands, integrated with Fermi Large Area Telescope (LAT) observations. Spectral analysis was conducted on the X-ray observations using the XSPEC software, and the results were compared with optical, UV, and γ-ray flux measurements and photon index values.

Results. Our key findings include the identification of three distinct zones in the X-ray photon index-flux plot, characterized by high flux and a hard photon index (zone 1), high flux and a soft photon index (zone 2), and low flux and a soft photon index (zone 3). Before ∼2017, 1H 0323 + 342 moved back and forth between zones 1 and 2; after that epoch, it transitioned to zones 2 and 3. Correspondingly, we observed a decreasing jet activity in the Fermi/LAT data and a reduction in the accretion rate in optical/UV data from Swift/UVOT.

Conclusions. We interpret these observations in the framework of an intermittent jet scenario, driven by radiation-pressure instability in the accretion disk.