Results 71 to 80 of about 1,130 (187)

Cosmic Dust Flux During the Quaternary: The Record of Large Scoriaceous and Unmelted Micrometeorites From the Transantarctic Mountains Collection

open access: yesJournal of Geophysical Research: Planets, Volume 131, Issue 7, July 2026.
Abstract We estimate the cosmic dust flux to Earth through the study of rare micrometeorites that preserve part of their precursor features during atmospheric entry heating, namely unmelted and scoriaceous subtypes. Combining high‐precision mass balance measurements, X‐ray computed microtomography and scanning electron microscopy, we studied mass, size
S. Ottaviani   +7 more
wiley   +1 more source

Identifying Compton-thick Active Galactic Nuclei with a Machine Learning Algorithm in Chandra Deep Field-South

open access: yesThe Astrophysical Journal
Compton-thick active galactic nuclei (CT-AGNs), which are defined by column density N _H ≥ 1.5 × 10 ^24 cm ^−2 , emit feeble X-ray radiation, even undetectable by X-ray instruments.
Rui Zhang   +9 more
doaj   +1 more source

Chlorination‐Enabled Oxygen Control and Dual‐Sulfur Source Aided Trap Passivation to Unlock 8.24% Efficient Sb2S3 Photovoltaic Devices

open access: yesAdvanced Functional Materials, Volume 36, Issue 50, 22 June 2026.
This work demonstrates a scalable, low‐temperature synthesis strategy that combines a thioacetamide (TA)‐based dual sulfur source with CdS chlorination, enabling the formation of high‐quality Sb2S3 with a reduced open‐circuit voltage loss, resulting in improved device efficiency.
Vijay C. Karade   +16 more
wiley   +1 more source

Test for Echo: X-Ray Reflection Variability in the Seyfert-2 Active Galactic Nucleus NGC 4388

open access: yesThe Astrophysical Journal
We report on a study of the narrow Fe K α line and reflection spectrum in the well-known Seyfert-2 active galactic nucleus (AGN), NGC 4388. X-ray spectra summed from two extensive NICER monitoring campaigns, separated by years, show strong evidence of ...
Ben Gediman   +6 more
doaj   +1 more source

On the Properties of X-Ray Corona in Seyfert 1 Galaxies

open access: yesThe Astrophysical Journal
We carried out a uniform and systematic analysis of a sample of 112 nearby bright Seyfert 1 type active galactic nuclei, the observations of which were carried out by the Nuclear Spectroscopic Telescope Array between 2013 August and 2022 May.
Indrani Pal   +6 more
doaj   +1 more source

An Investigation of 5 yr Simultaneous X-Ray and Radio Light Curves of the Dwarf Seyfert Galaxy UGC 6728

open access: yesThe Astrophysical Journal
We present serendipitous simultaneous radio and X-ray light curves of the dwarf Seyfert galaxy UGC 6728 spanning 5 yr. The X-ray light curve exhibits a flaring period, followed by a gradual rise and decline.
Krista Lynne Smith   +2 more
doaj   +1 more source

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

BASS. XLIX. Characterization of Highly Luminous and Obscured AGNs: Local X-Ray and [Ne V]λ3426 Emission in Comparison with the High-redshift Universe

open access: yesThe Astrophysical Journal
We present a detailed analysis of the most luminous and obscured active galactic nuclei (AGNs) detected in the ultra-hard X-ray band (14–195 kev) by the Swift/Burst Alert Telescope. Our sample comprises 21 X-ray luminous ( ${\mathrm{log}}\,{L}_{{\rm{X}}}/
Alessandro Peca   +23 more
doaj   +1 more source

Stripe 82-XL: The ∼54.8 deg2 and ∼18.8 Ms Chandra and XMM-Newton Point-source Catalog and Number of Counts

open access: yesThe Astrophysical Journal
We present an enhanced version of the publicly available Stripe 82X catalog (S82-XL), featuring a comprehensive set of 22,737 unique X-ray point sources identified with a significance ≳4 σ .
Alessandro Peca   +11 more
doaj   +1 more source

Active galactic nuclei with ultrasoft X-ray emission

open access: yesThe Astrophysical Journal Supplement Series, 1992
The discovery of a class of AGN with clearly distinguishable soft X-ray components below 0.5 keV is reported. These AGN were detected through equivalent hydrogen column densities that are less than a few times 10 exp 20/sq cm. At least three kinds of AGN comprise this sample: low-redshift quasars and Seyfert galaxies that have only ultrasoft emission ...
F. A. Cordova   +5 more
openaire   +1 more source

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