3 papers
astro-ph.HE2025
The variability of active galaxies: I. Broad-band noise X-ray power spectra from XMM-Newton and Swift
Mehdy Lefkir, Simon Vaughan, Mike Goad +2
Accreting supermassive black holes at the centres of galaxies are the engine of active galactic nuclei (AGN). X-ray light curves of unabsorbed AGN show dramatic random variability…
astro-ph.GA2025
Modelling variability power spectra of active galaxies from irregular time series
Mehdy Lefkir, Simon Vaughan, Daniela Huppenkothen +2
A common feature of Active Galactic Nuclei (AGN) is their random variations in brightness across the whole emission spectrum, from radio to -rays. Studying the nature and origin…
astro-ph.HE2024
Investigating the Hard State of MAXI J1820+070: A Comprehensive Bayesian Approach to Black Hole Spin and Accretion Properties
Sachin D. Dias, Simon Vaughan, Mehdy Lefkir +1
We analyse the X-ray spectrum of the black hole X-ray binary MAXI J1820+070 using observations from XMM-Newton and NuSTAR during 'hard' states of its 2018-2019 outburst. We take a…