Results 81 to 90 of about 9,238,867 (222)

Investigating Layered Cratonic Lithosphere in the Fennoscandian Shield

Geochemistry, Geophysics, Geosystems, Volume 27, Issue 9, September 2026.
Abstract Cold, thick, and chemically depleted lithosphere with high seismic velocity and low attenuation characterizes continental cratons. However, discrepancies between xenolith‐based thermal constraints and those inferred from surface‐wave seismic models, together with the widespread observation of mid‐lithosphere discontinuities, challenge the ...
Yiran Huang, Colleen A. Dalton, Karen M. Fischer   +2 more
wiley   +1 more source

Investigating Model Dependencies for Obscured Active Galactic Nuclei: A Case Study of NGC 3982

The Astrophysical Journal
X-ray spectroscopy of heavily obscured active galactic nuclei (AGN) offers a unique opportunity to study the circumnuclear environment of accreting supermassive black holes.
Kristína Kallová, Peter G. Boorman, Claudio Ricci   +2 more
doaj   +1 more source

Very high energy gamma ray observations of southern hemisphere blazars [PDF]

, 1997
This thesis is concerned with very high energy γ-ray observations of blazars observable from the southern hemisphere. The data presented were obtained using the recently deployed University of Durham Mark 6 high sensitivity Čerenkov telescope. Chapters 1
Dickinson, M.R., Dickinson, Mark R.
core  

Genomic Insights Into the Multimetal Resilience and Biofilm‐Templated Nanorod Biosynthesis of Stenotrophomonas bentonitica BII‐R7: Bioremediation and Green Nanotechnology Implications

Microbial Biotechnology, Volume 19, Issue 9, September 2026.
Biofilm extracellular polymeric substances (EPS) in Stenotrophomonas bentonitica BII‐R7 direct the formation of crystalline trigonal selenium nanorods. Comparative genomics identifies a unique genetic toolkit underpinning EPS composition and metal resilience, positioning this strain as a platform for bioremediation and green nanomaterial synthesis ...
Eduardo Perez‐Muelas, Miguel Angel Ruiz‐Fresneda, Guillermo Lazuen‐Lopez, Tatiana Lopez‐Perez, Fouad Eddaoudi‐Lakraichi, Mohammed Bakkali, Mohamed Larbi Merroun   +6 more
wiley   +1 more source

Chandra Follow-up Observations of Swift-BAT-selected AGNs III

The Astrophysical Journal
The cosmic X-ray background (CXB) is dominated by the obscured and unobscured coronal light of active galactic nuclei (AGN). At energies below 10 keV, the CXB can be well explained by models taking into account the known AGN and the observed distribution
Isaiah S. Cox, Núria Torres-Albà, Stefano Marchesi, Peter Boorman, Xiurui Zhao, Ross Silver, Marco Ajello, Indrani Pal   +7 more
doaj   +1 more source

X-Ray Unveiling Events in a z ≈ 1.6 Active Galactic Nucleus in the 7 Ms Chandra Deep Field-South

The Astrophysical Journal, 2023
We investigate the extreme X-ray variability of a z = 1.608 active galactic nucleus in the 7 Ms Chandra Deep Field-South (XID 403), which showed two significant X-ray brightening events.
Li-Ming Yu, Bin Luo, W. N. Brandt, Franz E. Bauer, D. De Cicco, A. Fabian, R. Gilli, A. Koekemoer, M. Paolillo, D. P. Schneider, O. Shemmer, P. Tozzi, Jonathan R. Trump, C. Vignali, F. Vito, J.-X. Wang, Y. Q. Xue   +16 more
doaj   +1 more source

The 40K‐K dating system: 1. Improving data interpretation using new model calculations

Meteoritics &Planetary Science, Volume 61, Issue 9, Page 2187-2200, September 2026.
Abstract The 40K‐K cosmic‐ray exposure (CRE) dating system offers a promising method for determining exposure ages of iron meteorites by combining the radioactive cosmogenic 40K with the stable cosmogenic isotopes 39K and 41K. However, earlier applications relied on semi‐empirical production models and inconsistent analytical data sets, limiting their ...
Farshid Nozarian, Suzette Timmerman, Ingo Leya   +2 more
wiley   +1 more source

Testing Physical and Phenomenological Models to Explain the Origin of the Soft Excess in Type-1 AGN

The Astrophysical Journal
Active galactic nuclei (AGN) exhibit an excess of X-ray emission below ∼1 keV compared to the 2–10 keV continuum extrapolation. This feature is commonly named soft excess, and its origin is currently debated for type-1 AGN.
César Ivan Victoria-Ceballos, Omaira González-Martín, Josefa Masegosa, Anna Lia Longinotti, Donaji Esparza-Arredondo, Sinhué A. R. Haro-Corzo   +5 more
doaj   +1 more source

X-ray reverberation in Active Galactic Nuclei

, 2015
Narrow Line Type-1 Seyfert active galaxies can exhibit a high degree of variability in the X-ray regime. This thesis examines that variability in the context of reverberation models, in which a flare in activity has an extended, energy dependent, response. A novel method is developed for estimating the response function in different energy bands.
openaire   +2 more sources

The Response of Warm Absorbers to the Variations in the Ionizing Continuum in the Active Galaxy NGC 4051

The Astrophysical Journal
We present a time-resolved X-ray spectral analysis of the warm absorbers in the Seyfert galaxy NGC 4051, which has an active galactic nucleus (AGN), using observations from the Neutron Star Interior Composition Explorer (NICER).
Dev R. Sadaula, Timothy R. Kallman, Sibasish Laha   +2 more
doaj   +1 more source