X-ray reverberation lags from the 1.5 Seyfert galaxy NGC 5273

TL;DR

This study analyzes X-ray reverberation lags in NGC 5273, revealing iron line reflection from close to the black hole and suggesting a high inclination angle of the accretion disc.

Contribution

First detailed X-ray reverberation lag analysis of NGC 5273, providing insights into its accretion disc geometry and reflection features.

Findings

Detection of iron line reverberation lag at ~1000s

Evidence for reflection from material close to the black hole

Indication of a disc inclination ≥ 45°

Abstract

We present the results of X-ray spectral-timing analysis of a 90ks XMM-Newton observation of the nearby, broad line, early-type AGN NGC5273. The X-ray spectrum revealed the clear presence of a reflection component at high energies, with a clear signature of a narrow iron line at 6.4 keV, consistent with distant reflection. Applying a relativistic reflection model, we found only marginal evidence for a broader relativistic line component. However, cross-spectral analysis revealed that, between 4 and 6 $\times 10^{-4}$ Hz, the 5-8 keV band lagged the 2-3 keV band, implying reflection of the iron line from material close to the black hole. From the analysis of the lag-energy spectrum, we found a broad, but skewed line with a peak of $\approx$ 1000s at 7.5 keV relative to the continuum, which we interpret as the iron line in the reverberation spectrum from an illuminated accretion disc. From the asymmetry in the shape of lag-energy spectrum, we also found that the source is consistent with having an inclination $\geq 45^\circ$.