Reflection dominated X-ray spectra of Narrow Line Seyfert 1 Galaxies: Mrk 478 and EXO 1346.2+2645

TL;DR

This study analyzes multi-epoch X-ray spectra of two Narrow Line Seyfert 1 galaxies, revealing they are dominated by relativistic reflection from regions very close to rapidly spinning black holes, with spectral stability across epochs.

Contribution

It demonstrates that reflection dominates the X-ray spectra of Mrk 478 and EXO 1346.2+2645, supporting models involving light bending and small emission regions near spinning black holes.

Findings

Spectra are well described by relativistic reflection models.

Spectral variability is minimal across epochs.

Constant spectral properties support a single-component model.

Abstract

Multi-epoch XMM-Newton spectra of the two Narrow Line Seyfert 1 (NLS1), Mrk 478 and EXO 1346.2+2645, are presented. The data were fitted with different models, including the relativistically-blurred reflection model reflionx, which was found to give a good description of both spectra in all epochs. The two sources are reflection dominated with the illuminating continuum hidden from view. This can be explained either in terms of a corrugated disc or strong gravitational light bending effects. The emission from these two sources comes from a very small region (few gravitational radii), very close to a rapidly spinning black hole. Spectral variability analysis show that both sources have constant RMS spectra, and constant hardness ratios in all epochs, in agreement with a single spectral component. The constancy the spectrum between high and low states rules out alternative models such as partial covering.