6 papers
Energy dependence of the X-ray power spectrum in NGC4051 and NGC4395
V. A. Diamantopoulos, I. E. Papadakis, A. Akylas +3
Active galactic nuclei (AGNs) exhibit strong variability across the electromagnetic spectrum on a wide range of timescales, particularly in X-rays where fluctuations are both rapid…
Harnessing the XMM-Newton data: X-ray spectral modelling of 4XMM-DR11 detections and 4XMM-DR11s sources
A. Viitanen, G. Mountrichas, H. Stiele +13
The XMM-Newton X-ray observatory has played a prominent role in astrophysics, conducting precise and thorough observations of the X-ray sky for the past two decades. The most recen…
Measuring monster MBHs: maybe mighty, maybe merely massive
M. Gliozzi, A. Akylas, J. K. Williams +1
Accurate black hole mass (MBH) measurements in high-z galaxies are difficult yet crucial to constrain the growth of supermassive BHs, and to discriminate between competing BH seed…
Identification of high-redshift X-ray active galactic nuclei in the 4XMM-DR11 serendipitous catalogue using DES data: Comparative analysis with optically-selected QSOs
E. Pouliasis, A. Ruiz, I. Georgantopoulos +8
X-rays provide a robust method in identifying AGN. However, in the high-redshift Universe, their space density is relatively low, and, in combination with the small areas covered b…
The Compton-thick AGN luminosity function in the local Universe: A robust estimate combining BAT detections and NuSTAR spectra
I. Georgantopoulos, E. Pouliasis, A. Ruiz +1
The Compton-thick Active Galactic Nuclei (AGN) arguably constitute the most elusive class of sources as they are absorbed by large column densities above logN_H(cm^-2)=24. These ex…
Towards a complete census of luminous Compton-thick Active Galactic Nuclei in the local Universe
A. Akylas, I. Georgantopoulos, P. Gandhi +2
X-ray surveys provide the most efficient means for the detection of Active Galactic Nuclei (AGN). However, they face difficulties in detecting the most heavily obscured Compton-thi…