Results 51 to 60 of about 217,086 (193)

No Small-scale Radio Jets Here: Multiepoch Observations of Radio Continuum Structures in NGC 1068 with the VLBA

The Astrophysical Journal, 2023
We present recent Very Long Baseline Array (VLBA) 5 GHz radio observations of the nearby, luminous Seyfert 2 galaxy NGC 1068 for comparison to similar VLBA observations made on 1997 April 26.
Travis C. Fischer, Megan C. Johnson, Nathan J. Secrest, D. Michael Crenshaw, Steven B. Kraemer   +4 more
doaj   +1 more source

A comprehensive review of radiation shielding concrete: Properties, design, evaluation, and applications

Structural Concrete, Volume 26, Issue 2, Page 1809-1855, April 2025.
Abstract This review paper provides a comprehensive analysis of radiation shielding concrete, covering its properties, design, evaluation, and applications. It begins with an introduction, stating the objective and scope. The paper explores radiation shielding basics, including ionizing radiation, shielding principles, and materials used for shielding.
Salim Barbhuiya, Bibhuti Bhusan Das, Paul Norman, Tanvir Qureshi   +3 more
wiley   +1 more source

An Excess of Active Galactic Nuclei Triggered by Galaxy Mergers in MaNGA Galaxies of Stellar Mass ∼1011 M ⊙

The Astrophysical Journal
To facilitate new studies of galaxy-merger-driven fueling of active galactic nuclei (AGNs), we present a catalog of 387 AGNs that we have identified in the final population of over 10,000 z < 0.15 galaxies observed by the Sloan Digital Sky Survey-IV ...
Julia M. Comerford, Rebecca Nevin, James Negus, R. Scott Barrows, Michael Eracleous, Francisco Müller-Sánchez, Namrata Roy, Aaron Stemo, Thaisa Storchi-Bergmann, Dominika Wylezalek   +9 more
doaj   +1 more source

Impact crater lake evolution and concomitant hydrothermal mineralization recorded by the Wörnitzostheim drill core at the Ries impact structure, Germany

Meteoritics &Planetary Science, Volume 60, Issue 4, Page 795-822, April 2025.
Abstract Impact‐generated hydrothermal systems and postimpact crater lake systems are well‐documented geological phenomena; however, evidence of hydrothermal venting into impact crater lake systems has rarely been reported. We investigated the well‐preserved contact between hydrothermally altered impact melt‐bearing breccia (outer/surficial suevite ...
Matthew J. O. Svensson, Gordon R. Osinski, Fred J. Longstaffe, Timothy A. Goudge, Haley M. Sapers   +4 more
wiley   +1 more source

Panic at the ISCO: Time-varying Double-peaked Broad Lines from Evolving Accretion Disks Are Common among Optically Variable AGNs

The Astrophysical Journal
About 3%–10% of Type I active galactic nuclei (AGNs) have double-peaked broad Balmer lines in their optical spectra originating from the motion of gas in their accretion disk.
Charlotte Ward, Suvi Gezari, Peter Nugent, Matthew Kerr, Michael Eracleous, Sara Frederick, Erica Hammerstein, Matthew J. Graham, Sjoert van Velzen, Mansi M. Kasliwal, Russ R. Laher, Frank J. Masci, Josiah Purdum, Benjamin Racine, Roger Smith   +14 more
doaj   +1 more source

Extragalactic Gamma-ray Background Radiation from Beamed and Unbeamed Active Galactic Nuclei [PDF]

, 2011
The origin of the extragalactic gamma-ray background (EGRB) radiation has been a mystery in astrophysics for a long time. Recently the Fermi gamma-ray satellite (Fermi) has revealed that ~22% of the unresolved EGRB would be explained by blazars, which are one population of beamed active galactic nuclei (AGNs).
arxiv   +1 more source

Cosmic Rays and the Askaryan Effect Reveal Subsurface Structure and Buried Ice on the Moon

Geophysical Research Letters, Volume 52, Issue 6, 28 March 2025.
Abstract We present the first full‐wavelength numerical simulations of the electric field generated by cosmic ray impacts into the Moon. Billions of cosmic rays fall onto the Moon every year. Ultra‐high energy cosmic ray impacts produce secondary particle cascades within the regolith and subsequent coherent, wide‐bandwidth, linearly‐polarized radio ...
E. S. Costello, R. R. Ghent, A. Romero‐Wolf, P. W. Gorham, P. G. Lucey, C. J. Tai Udovicic, P. Linton, A. Ludwig, K. McBride, C. Miki, E. Oberla, J. Rolla, A. Jung   +12 more
wiley   +1 more source

Probing the High-frequency Variability of NGC 5044: The Key to Active Galactic Nucleus Feedback

The Astrophysical Journal
The active galactic nucleus (AGN) feeding and feedback process in the centers of galaxy clusters and groups is still not well understood. NGC 5044 is the ideal system in which to study AGN feedback. It hosts the largest known reservoir of cold gas in any
Gerrit Schellenberger, Ewan O’Sullivan, Laurence P. David, Jan Vrtilek, Charles Romero, Glen Petitpas, William Forman, Simona Giacintucci, Mark Gurwell, Christine Jones, Kamlesh Rajpurohit, Francesco Ubertosi, Tiziana Venturi   +12 more
doaj   +1 more source

Investigating the Correlation of Outflow Kinematics with Radio Activity. VII. Gas Outflows in AGNs

The Astrophysical Journal, 2023
We explore the relationship between the ionized gas outflows and radio activity using a sample of ∼6000 active galactic nuclei (AGNs) at z < 0.4 with the kinematical measurement based on the $\left[{\rm{O}}\,{\rm\small{III}}\right]$ line profile and the ...
Ashraf Ayubinia, Jong-Hak Woo, Suvendu Rakshit, Donghoon Son   +3 more
doaj   +1 more source

A Radio Census of Binary Supermassive Black Holes [PDF]

, 2010
Using archival VLBI data for 3114 radio-luminous active galactic nuclei, we searched for binary supermassive black holes using a radio spectral index mapping technique which targets spatially resolved, double radio-emitting nuclei. Only one source was detected as a double nucleus.
arxiv   +1 more source