activity
20202026
most citedQuasars as standard candles III. Validation of a new sample for cosmological studies

176 citations · 331 across the 34 of their papers we have counts for

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10 papers · 1 filter

astro-ph.HE2026

Observation of A Solar Like Magnetic Reconnection Event in an AGN Corona with XRISM

Gal Vardi, Ehud Behar, Liyi Gu +14

The X-ray source in AGN is commonly referred to as the corona by analogy to stellar coronae. The similarities between the two suggest that the heating mechanism of AGN coronae is m…

astro-ph.HE2026

The X-ray-to-UV relation does not evolve in homogeneous quasar samples

G. Risaliti, E. Lusso, E. Nardini +6

We present a new, highly homogeneous quasar sample with X-ray and UV observations optimized to reliably estimate distances via the non-linear X-ray-to-UV relation. Cross-matching t…

astro-ph.HE2026★ 1 cited

Delving into the depths of NGC 3783 with XRISM: V. Broad-band modeling of ionized outflows

Keqin Zhao, Jelle S. Kaastra, Liyi Gu +7

The Seyfert 1 galaxy NGC 3783 hosts a multiphase warm absorber (WA) that has been extensively studied in the X-ray band. High-resolution spectra from 2000-2001 revealed a complex o…

astro-ph.HE2025★ 10 cited

Delving into the depths of NGC 3783 with XRISM IV. Mapping of the accretion flow with Fe K emission lines

Chen Li, Jelle S. Kaastra, Liyi Gu +18

Using XRISM/Resolve time-averaged spectra of the well-known Seyfert-1.5 active galactic nucleus (AGN) in NGC 3783, we investigate the nature of the Fe K emission…

astro-ph.HE2025★ 10 cited

Delving into the depths of NGC 3783 with XRISM III. Birth of an ultrafast outflow during a soft flare

Liyi Gu, Keigo Fukumura, Jelle Kaastra +18

The 2024 X-ray/UV observation campaign of NGC 3783, led by XRISM, revealed the launch of an ultrafast outflow (UFO) with a radial velocity of 0.19c (57000 km/s). This event is sync…

astro-ph.HE2025★ 3 cited

The Advanced X-ray Imaging Satellite (AXIS) Community Science Book

Michael Koss, Nafisa Aftab, Steven W. Allen +395

The AXIS Community Science Book represents the collective effort of 592 scientists worldwide to define the transformative science enabled by the Advanced X-ray Imaging Satellite (A…

astro-ph.HE2025★ 1 cited

The X-rayUV Luminosity Relation of eROSITA Quasars

Andrea Sacchi, Guido Risaliti, Matilde Signorini +3

The non-linear relation between the UV and X-ray luminosity in quasars has been studied for decades. However, as we lack a comprehensive model able to explain it, its investigation…

astro-ph.HE2024

AGN STORM 2: IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-ray Spectroscopy

Fatima Zaidouni, Erin Kara, Peter Kosec +45

We present the results of the XMM-Newton and NuSTAR observations taken as part of the ongoing, intensive multi-wavelength monitoring program of the Seyfert 1 galaxy Mrk 817 by the…

astro-ph.HE2023

AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817

Jack M. M. Neustadt, Christopher S. Kochanek, John Montano +49

We fit the UV/optical lightcurves of the Seyfert 1 galaxy Mrk 817 to produce maps of the accretion disk temperature fluctuations resolved in time and radius. The maps are…

astro-ph.HE2023★ 20 cited

X-ray properties and obscured fraction of AGN in the J1030 Chandra field

Matilde Signorini, Stefano Marchesi, Roberto Gilli +13

The 500ks Chandra ACIS-I observation of the field around the quasar SDSS J1030+0524 is currently the 5th deepest extragalactic X-ray survey. The rich multi-band coverage o…