From the 1 of 10 linked papers with an AI index.
10 papers
Profile Analysis of the Multiwavelength 2.1-year Oscillations of PG 1553+113
P. Peñil, P. Peñil, N. Torres-Albà +8
We investigate the morphology of the oscillation profiles of the blazar PG~1553+113 in relation to its well-known 2.1 yr periodicity. We identify individual cycles in the …
Evidence for a bursty -ray QPO in the neutrino-associated FSRQ PKS 1424418 using Fast Template Periodograms and Machine Learning
Aaron A. Maldonado, Alberto DomÃnguez, Adithiya Dinesh +4
Standard frequency-domain searches for quasi-periodic oscillations (QPOs) in active galactic nuclei generally assume sinusoidal variability. However, -ray blazar emission often…
X-ray Absorption Variability in NGC 1142: Another Constraint on the Nature of the Torus/Broad-Line Region in Active Galactic Nuclei
Isaiah S. Cox, Núria Torres-AlbÃ, Stefano Marchesi +5
The paper analyzes nine X‑ray observations of the active galaxy NGC 1142 over ~20 years to study changes in line‑of‑sight column density, using torus models to infer the geometry a…
The hidden variability of the torus in local Active Galactic Nuclei: 20 years of Chandra, XMM-Newton, and NuSTAR observations
Vittoria Elvezia Gianolli, Nuria Torres-Alba, Stefano Marchesi +9
X-ray absorption variability in active galactic nuclei (AGN) provides key constraints on the structure and dynamics of the circumnuclear obscuring medium, the so-called torus. A fr…
Transient Relativistic Iron Emission Line from an X-ray Flaring Supermassive Black Hole
Xiurui Zhao, Marco Ajello, Francesca Civano +16
We report the discovery of the first transient relativistic iron Kα line in an Active Galactic Nucleus (AGN) J1047+5907. The line was detected 21.5 days (rest-frame) after an X-ra…
Fast X-ray Variability from the Coronae of Supermassive Black Holes
Xiurui Zhao, Luca Comisso, Stefano Marchesi +4
We present the first systematic study of short-timescale X-ray variability in radio-quiet active galactic nuclei (AGN), utilizing archival Chandra observations of approximately 3,0…