Results 31 to 40 of about 787 (145)

Studies of Seyfert galaxies in Fesenkov Astrophysical Institute

Communications of the Byurakan Astrophysical Observatory, 2020
This article provides an overview of the main research results of a large group of Seyfert galaxies, carried out at Fesenkov Astrophysical Institute (FAI) over the past 50 years. Spectral observations have been performed since 1970. At an early stage, a three cascade image-tube (UM-92) was used as a radiation receiver.
E. Denissyuk, R. Valiullin, CH. Omarov, S. Shomshekova, M. Krugov, B. Omar   +5 more
openaire   +1 more source

Nanoscale space weathering features in mature lunar soil revealed by TEM and APT

Meteoritics &Planetary Science, EarlyView.
Abstract Space weathering significantly alters the optical, chemical, and structural properties of lunar regolith at micro‐ and nanoscales; yet detailed nanoscale variability within individual soils remains underexplored. Here we apply transmission electron microscopy (TEM) and atom probe tomography to four mineral grains (olivine, ilmenite, and two ...
Jennika Greer, Alexander M. Kling, Luke Daly, Dieter Isheim, David N. Seidman, Michelle S. Thompson, Philipp R. Heck   +6 more
wiley   +1 more source

Aircraft Ionizing Radiation Exposure for Solar Cycle 24/25 From ARMAS and NAIRAS

Space Weather, Volume 24, Issue 7, July 2026.
Abstract Exposure to ionizing radiation from galactic cosmic rays and solar energetic particles at aviation flight altitudes can have an adverse effect on human health. Although airline crews are classified as radiation workers by the International Commission on Radiological Protection (ICRP), in most countries, their level of exposure is unquantified ...
Daniel B. Phoenix, Christopher J. Mertens, Guillaume P. Gronoff, W. Kent Tobiska   +3 more
wiley   +1 more source

New Observations of Cosmic Noise Absorption in the South American Magnetic Anomaly (SAMA) Using a Next‐Generation Riometer

Space Weather, Volume 24, Issue 7, July 2026.
Abstract This study reports the first observations of cosmic noise power (CNP) and cosmic noise absorption (CNA) obtained with a next‐generation riometer installed at the Southern Space Observatory (SSO/INPE) in Brazil, located within the South American Magnetic Anomaly (SAMA).
J. Moro, E. Correia, C. M. Wrasse, J. R. Costa, J. V. Bageston, C. M. Denardini, A. J. Valcorte, L. C. A. Resende, A. M. Santos, L. A. da Silva, J. P. Marchezi, T. S. Trondsen   +11 more
wiley   +1 more source

Revealing the Formation of the <20 MeV Inner Proton Radiation Belt at L ∼ 2 During the 10–11 May 2024 Superstorm

Geophysical Research Letters, Volume 53, Issue 11, 16 June 2026.
Abstract A new proton radiation belt was identified during the geomagnetic superstorm of 10–11 May 2024. To investigate its origin, we use an MHD‐test particle simulation to model solar energetic proton (SEP) trapping and the evolution of the initial trapped proton population during the storm.
Murong Qin, Mary K. Hudson, Miles Engel, Brian T. Kress, Zhao Li, Maulik Patel, Wen Li, Kevin Pham, William R. Johnston, Xinlin Li, Shawn Young   +10 more
wiley   +1 more source

Slowly Rotating Traversable Wormholes Supported by Radially Varying String‐Fluid Matter: From Regular Geometries to Photon Trajectories

Annalen der Physik, Volume 538, Issue 6, June 2026.
This study examines slowly rotating traversable wormholes supported by string fluids whose properties change with radius. The matter smoothly shifts from a de Sitter‐like core to a string‐dominated exterior, producing a regular, horizon‐free spacetime.
A. Errehymy, B. Turimov, Meraj Ali Khan, S. Usanov, Z. Yasakov, Z. Avezmuratova   +5 more
wiley   +1 more source

Repeating Nuclear Transients From Repeating Partial Tidal Disruption Events

Astronomische Nachrichten, Volume 347, Issue 5, June 2026.
ABSTRACT Extragalactic nuclear transients that exhibit repeating outbursts can be modeled as the repeated dynamical interaction between bound stars and supermassive black holes (SMBHs). A subset of these transients, with recurrence timescales of months‐to‐years, have been explained as accretion flares from the repeated tidal stripping of a star by an ...
Ananya Bandopadhyay, Eric R. Coughlin, Julia Fancher, C. J. Nixon, Dheeraj R. Pasham   +4 more
wiley   +1 more source

Astrophysical black holes: An explanation for the galaxy quenching

Journal of High Energy Astrophysics
In light of increasing observational evidence supporting the existence of ultra-compact objects, we adopt the term astrophysical black hole to refer to any object having a huge mass confined within a sufficiently small region of spacetime. This terminology encompasses both the classical black hole solutions predicted by general relativity, as well as ...
Jay Verma Trivedi, Pankaj S. Joshi, Gopal Krishna, Peter L. Biermann   +3 more
openaire   +2 more sources

Groups of galaxies in the Center for Astrophysics redshift survey

The Astrophysical Journal, 1989
By applying the Huchra and Geller (1982) objective group identification algorithm to the Center for Astrophysics' redshift survey, a catalog of 128 groups with three or more members is extracted, and 92 of these are used as a statistical sample. A comparison of the distribution of group centers with the distribution of all galaxies in the survey ...
Massimo Ramella, Margaret J. Geller, John P. Huchra   +2 more
openaire   +1 more source

Quantifying the Impact of Relativistic Precession on Tidal Disruption Event Light Curves

Astronomische Nachrichten, Volume 347, Issue 5, June 2026.
ABSTRACT The tidal field of a black hole can turn a star into a gas stream whose orbit can precess, especially if the a black hole is rapidly spinning. In this work, we investigate the impact of precession on the light curves of tidal disruption events (TDE).
Diego Calderón, Ondřej Pejcha, Brian D. Metzger, Paul C. Duffell, Stephan Rosswog   +4 more
wiley   +1 more source