Insights into jet-NLR energetics in PMN J0948+0022

TL;DR

The paper investigates whether energy from the relativistic jet in the γ-ray–emitting NLS1 PMN J0948+0022 is deposited into the narrow-line region (NLR) to drive optical spectral variability. It uses back-of-the-envelope energetics derived from X-shooter and MUSE optical spectra, complemented by contemporaneous γ-ray (Fermi) and 37 GHz radio data to constrain jet powers in the γ-ray and radio bands. The outflow kinetic power is found to be $P_{out} \sim (8.8\times10^{42} - 1.4\times10^{43})$ erg s$^{-1}$, while jet powers in the γ-ray and radio components are $P_{\gamma,kin} \sim (2.4-2.5)\times10^{45}$ erg s$^{-1}$ and $P_{radio,kin} \sim (4.8-7.3)\times10^{44}$ erg s$^{-1}$, yielding jet-to-outflow ratios of roughly $0.35\%$–$1.9\%$. This supports a jet–NLR interaction scenario in which jet energy drives observable optical variability, illustrating a measurable mode of feedback in γ-ray–emitting NLS1s and emphasizing the value of coordinated multi-wavelength monitoring. The study also connects radio jet morphology changes with optical and γ-ray variability, contributing to a broader understanding of circumnuclear gas dynamics under jet influence.

Abstract

The analysis of the optical spectra of PMN J0948+0022 showed significant variations in the spectral lines that, when combined with the Fermi $γ$-ray light curve and radio observations reported by other authors, were interpreted as the result of interactions between the relativistic jet and the narrow-line region (NLR). In this work, we present order-of-magnitude calculations of the energetics associated with this proposed jet-NLR interaction. We demonstrate that the observed outflows are capable of absorbing a fraction of the jet energy and converting it into kinetic energy. This mechanism provides a natural explanation for the optical spectral variability recorded with the X-shooter and Multi-Unit Spectroscopic Explorer (MUSE) instruments. Our results support the scenario in which feedback from the relativistic jet can dynamically influence the circumnuclear gas, offering new insights into the coupling between jets and the NLR in $γ$-ray-emitting narrow-line Seyfert 1 galaxies.