A Jet Model for the Broadband Spectrum of the Seyfert-1 Galaxy NGC 4051

TL;DR

This study models the broadband spectrum of NGC 4051 using a relativistic jet framework, demonstrating that the jet can explain the observed emission across radio to X-ray wavelengths, with implications for jet activity in narrow line Seyfert 1 galaxies.

Contribution

It provides the first comprehensive broadband spectral modeling of NGC 4051 with a jet model, linking multi-wavelength emission to jet physics and black hole activity.

Findings

Jet model successfully explains broadband emission after host galaxy contribution is considered.

High variability in UV and X-ray suggests optically thin synchrotron emission near the black hole.

Narrow line Seyfert 1 galaxies likely host jetted outflows similar to low-luminosity AGNs.

Abstract

Recent radio VLBI observations of the ~parsec-scale nuclear region of the narrow line Seyfert 1 galaxy NGC 4051 hint toward the presence of outflowing plasma. From available literature we have collected high-quality, high-resolution broadband spectral energy distribution data of the nuclear region of NGC 4051 spanning from radio through X-rays, to test whether the broadband SED can be explained within the framework of a relativistically outflowing jet model. We show that once the contribution from the host galaxy is taken into account, the broadband emission from the active galactic nucleus of NGC 4051 can be well described by the jet model. Contributions from dust and ongoing star-formation in the nuclear region tend to dominate the IR emission even at the highest resolutions. In the framework of the jet model, the correlated high variability of the extreme ultraviolet and X-rays compared to other wavelengths suggests that the emission at these wavelengths is optically thin synchrotron originating in the particle acceleration site(s) in the jet very close (few $r_g=GM_{BH}/c^2$) to the central supermassive black hole of mass M_{BH}. Our conclusions support the hypothesis that narrow line Seyfert 1 galaxies (which NGC 4051 is a member of) harbor a "jetted" outflow with properties similar to what has already been seen in low-luminosity AGNs and stellar mass black holes in hard X-ray state.