Results 41 to 50 of about 77,605 (280)

Accretion in Active Galactic Nuclei [PDF]

open access: yesProceedings of Accretion Processes in Cosmic Sources – II — PoS(APCS2018), 2019
We review the current status of the understanding how the accretion onto the central black hole proceeds in Active Galaxies. Standard accretion disk is a key element in all relatively bright active galaxies like Seyferts and quasars, although it is not present in very low luminosity sources, like Sgr A*.
Mohammad Hassan Naddaf, Bozena Czerny
openaire   +3 more sources

NuSTAR Detection of an Absorption Feature in ESP 39607: Evidence for an Ultrafast Inflow?

open access: yesThe Astrophysical Journal
We report the serendipitous discovery of an absorption feature at 4.8 keV in the NuSTAR spectra of ESP 39607, a Seyfert 2 galaxy at z = 0.201, observed in 2023 May and 2024 August. The feature is detected in both observations with individual significance
Alessandro Peca   +6 more
doaj   +1 more source

The Messy Nature of Fiber Spectra: Star–Quasar Pairs Masquerading as Dual Type 1 AGNs

open access: yesThe Astrophysical Journal, 2023
Theoretical studies predict that the most significant growth of supermassive black holes (SMBHs) occurs in late-stage mergers, coinciding with the manifestation of dual active galactic nuclei (AGNs), and both major and minor mergers are expected to be ...
Ryan W. Pfeifle   +7 more
doaj   +1 more source

Highly Efficient Platinum‐Free Photocatalytic Hydrogen Evolution From Low‐cost Conjugated Polymer Nanoparticles

open access: yesAdvanced Materials, EarlyView.
Platinum‐free hydrogen photocatalysis is achieved using dibenzothiophene‐S,S‐sulfoxide‐based conjugated polymers, self‐assembled into nanoparticles via nanoprecipitation. Through side chain engineering and donor–acceptor design, these materials reach a hydrogen evolution rate of 209 mmol g⁻¹ h⁻¹. The structure–function insights presented here establish
Alexandre Holmes   +11 more
wiley   +1 more source

THE EVOLUTION OF ACTIVE GALACTIC NUCLEI AND THEIR SPINS [PDF]

open access: yesThe Astrophysical Journal, 2013
ApJ, in ...
Marek Sikora   +5 more
openaire   +4 more sources

A UV to X-Ray View of Soft Excess in Type 1 Active Galactic Nuclei. I. Sample Selection and Spectral Profile

open access: yesThe Astrophysical Journal
A core sample of 59 unobscured type 1 active galactic nuclei (AGNs) with simultaneous XMM-Newton X-ray and UV observations is compiled from the archives to probe the nature of soft X-ray excess (SE).
Shi-Jiang Chen   +7 more
doaj   +1 more source

The parsec scale region of Active Galactic Nuclei in the IR [PDF]

open access: yes, 2004
First results from the AGN-Heidelberg program aimed at spatially resolving the central pc region of the closest Active Galactic Nuclei are presented. The core region of prototype active nuclei are clearly unveiled at IR waves and at distances from the ...
Meisenheimer, Klaus, Prieto, M. Almudena
core   +2 more sources

How to Manufacture Photonic Metamaterials

open access: yesAdvanced Materials Technologies, EarlyView.
Metamaterials boast applications such as invisibility and “hyperlenses” with resolution beyond the diffraction limit, but these applications haven’t been exploited in earnest and the market for them hasn’t grown much likely because facile and economical methods for fabricating them without defect has not emerged.
Apurba Paul, Gregory Timp
wiley   +1 more source

Active galactic nuclei: what’s in a name? [PDF]

open access: yesThe Astronomy and Astrophysics Review, 2017
Accepted for publication in Astronomy & Astrophysics Review, 56 pages, 25 ...
P. Padovani   +10 more
openaire   +4 more sources

The Halo Occupation Distribution Modeling of X-Ray-selected Active Galactic Nuclei at 0.6 < z < 2.6 in the COSMOS Field

open access: yesThe Astrophysical Journal
We conduct precise measurements of active galactic nucleus (AGN) clustering at z ∼ 1 and z ∼ 2 by measuring the two-point cross-correlation function (CCF) between galaxies and X-ray-selected AGNs, and the two-point autocorrelation function (ACF) of ...
Hiroyuki Ikeda   +8 more
doaj   +1 more source

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