Broad-band spectral analysis of Mrk 926 using multi-epoch X-ray observations

Abstract

ABSTRACT The X-ray spectra of some active galactic nuclei (AGNs) show a soft X-ray excess, emission in excess to the extrapolated primary X-ray continuum below 2 keV. Recent studies have shown that this soft excess can be described well as originating from either a relativistic ionized reflection, the extreme blurring of the reprocessed emission from the innermost region of the accretion disc, or Comptonization from an optically thick and warm region called the ‘warm corona’, in which electron scattering is the dominant source of opacity. To constrain the origin of the soft excess in the Seyfert 1 galaxy Mrk 926, we carry out a multi-epoch X-ray spectral study using observations from Suzaku (2009), XMM–Newton and NuSTAR (2016), and NuSTAR and Swift-XRT (2021). The broad-band X-ray spectra of Mrk 926 contains a thermally Comptonized primary continuum, a variable soft excess, and distant reflection. We find that in Mrk 926 as in so many sources, it is difficult to make a definite statement as to what is causing the observed soft excess. A warm coronal-like component is slightly preferred by the data but a reflection origin is also possible. Using archival radio data, we detect an optically thin radio component in our broad-band study of Mrk 926. While this component is consistent with an optically thin radio jet, future multiwavelength observations including high spatial resolution radio observations at multiple frequencies are required to probe the origin of the radio emission in more detail.