activity
20002023
most citedX-ray Spectral Variability and Rapid Variability of the Soft X-ray Spectrum Seyfert 1 Galaxies Ark 564 and Ton S180

426 citations · 3.7k across the 70 of their papers we have counts for

collaborators

69 papers

astro-ph.HE2023★ 25 cited

Discovery of the luminous X-ray ignition eRASSt J234402.9352640; I. Tidal disruption event or a rapid increase in accretion in an active galactic nucleus?

D. Homan, M. Krumpe, A. Markowitz +17

In November 2020, a new, bright object, eRASSt J234402.9352640, was discovered in the second all-sky survey of SRG/eROSITA. The object brightened by a factor of at least 150 in…

astro-ph.HE2022★ 73 cited

Deciphering the extreme X-ray variability of the nuclear transient eRASSt J045650.3-203750: A likely repeating partial tidal disruption event

Zhu Liu, A. Malyali, M. Krumpe +17

(Abridged) In this paper, we present the results of an exceptional repeating X-ray nuclear transient, eRASSt J045650.3-203750 (hereafter J0456-20), uncovered by SRG/eROSITA in a qu…

astro-ph.HE2022★ 13 cited

Rapid X-ray Variability in Mkn 421 during a Multiwavelength Campaign

Alex G. Markowitz, Krzysztof Nalewajko, Gopal Bhatta +47

The study of short-term variability properties in AGN jets has the potential to shed light on their particle acceleration and emission mechanisms. We report results from a four-day…

astro-ph.HE2022★ 24 cited

High-density disc reflection spectroscopy of low-mass active galactic nuclei

L. Mallick, A. C. Fabian, J. A. García +13

The standard alpha-disc model predicts an anti-correlation between the density of the inner accretion disc and the black hole mass times square of the accretion rate, as seen in hi…

astro-ph.HE2021★ 18 cited

Inferring the morphology of AGN torus using X-ray spectra: A reliability study

Tathagata Saha, Alex G. Markowitz, Johannes Buchner

Numerous X-ray spectral models have been developed to model emission reprocessed by the torus of an active galactic nucleus (AGN), e.g., UXCLUMPY, CTORUS, and MYTORUS. They span a…

astro-ph.GA2021★ 139 cited

Event Horizon Telescope observations of the jet launching and collimation in Centaurus A

Michael Janssen, Heino Falcke, Matthias Kadler +236

Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimeter wavelengths have the power to reveal the launching and initial collimation region of e…