Results 21 to 30 of about 4,016,739 (216)
LRS Bianchi Type‐I String Cosmological Models in f(Q) Gravity
Journal of Mathematics, Volume 2023, Issue 1, 2023., 2023 In the current study, we studied a f(Q)‐gravitational, anisotropic, locally rotationally symmetric (LRS), Bianchi type‐I spacetime universe. We have adopted the freely chosen function fQ=Q+αQ, where α is a model‐free parameter. We assumed that the universe is filled with dusty string fluid and that the shear scalar (σ) and the expansion scalar (θ) are ...
Mukesh Kumar +5 more
wiley +1 more source
Chemical abundances in the dwarf galaxy NGC 4163 based on the nebular and auroral emission lines
Astronomische Nachrichten, Volume 343, Issue 9-10, November-December 2022., 2022 Abstract We constructed an oxygen abundance map and N/O ratio map of the unusually low excitation dwarf irregular galaxy NGC 4163 based on publicly available spectroscopy obtained by the MaNGA survey. We detected auroral emission line [O II]λλ$$ \lambda \lambda $$7320,7330 which allows us to measure chemical abundance by direct Te$$ {\mathrm{T}}_e ...
I. A. Zinchenko, L. S. Pilyugin
wiley +1 more source
CATALOG OF VARIABILITY PERIODS OF EXTRAGALACTIC RADIO SOURCES AT CENTIMETER WAVELENGTHS
Radio Physics and Radio Astronomy, 2016 Purpose: Study of the variability of flux density of extragalactic radio sources (3C 273, 3C 120, 3C 345, 3C 446, 3C 454.3, OJ 287, OT 081, BL Lac, DA 55, CTA 102) according to a long-term (1965–2011) monitoring at 14.5, 8, 4.8 GHz made with a 26-m ...
M. I. Ryabov +2 more
doaj +1 more source
A Comprehensive Observational Study of the FRB 121102 Persistent Radio Source
The Astrophysical Journal, 2023 FRB 121102 is the first fast radio burst to be spatially associated with a persistent radio source (QRS 121102), the nature of which remains unknown. We constrain the physical size of QRS 121102 by measuring its flux-density variability with the VLA from
Ge Chen, Vikram Ravi, Gregg W. Hallinan
doaj +1 more source
Soft X‐Ray Imaging of Magnetopause Reconnection Outflows Under Low Plasma‐β Solar Wind Conditions
Geophysical Research Letters, Volume 49, Issue 19, 16 October 2022., 2022 Abstract We examined soft X‐ray emission by the solar wind charge‐exchange process around the Earth's magnetosphere using a global magnetohydrodynamic simulation model. The dayside magnetopause reconnection heats and accelerates the plasma whereby the X‐ray emission becomes as bright as ∼6 × 10−6 eV cm−3 s−1 under the southward interplanetary magnetic ...
Yosuke Matsumoto, Yoshizumi Miyoshi
wiley +1 more source
A Wideband Polarization Observation of Hydra A with the Jansky Very Large Array
The Astrophysical Journal, 2023 We present the results of a wideband high-resolution polarization study of Hydra A, one of the most luminous FR I radio galaxies known and among the most well studied. The radio emission from this source displays extremely large Faraday rotation measures
Lerato Baidoo +5 more
doaj +1 more source
ENVIRONMENT DENSITY OF A GIANT RADIO STRUCTURE FOR GALAXIES AND QUASARS WITH STEEP RADIO SPECTRA [PDF]
Radio Physics and Radio Astronomy, 2021 Purpose: Estimate of the environment density of giant (with the linear size of about megaparsec) radio structures for galaxies and quasars with steep low-frequency spectra taken from the UTR-2 catalogue. Study of the cosmological evolution of environment
A. P. Miroshnichenko
doaj +1 more source
Radio Physics and Radio Astronomy, 2017 Purpose: From April 2017, a monitoring program of observations has been started at the RT-16 telescope of Ventspils Radio Astronomy Center (frequencies 5, 6.1, 6.7, 8.4 GHz) to study the intraday and interdiurnal variability of extragalactic radio ...
A. L. Sukharev +4 more
doaj +1 more source
Depolarization of Extragalactic Radio Sources [PDF]
Symposium - International Astronomical Union, 1982 In the last decade correlations of the depolarization parameter λd with several parameters, i.e., the radio luminosity L, redshift z, and source size D have been investigated by several authors, where λd is the wavelength at which the percentage polarization drops to its half maximum. Kronberg ET AL.
M. Inoue, H. Tabara
openaire +1 more source
A search for candidate radio supernova remnants in the nearby irregular starburst galaxies NGC 4214 and NGC 4395 [PDF]
Serbian Astronomical Journal, 2005 We present the results of a search for new candidate radio supernova remnants (SNRs) in the nearby starburst irregular galaxies NGC 4214 and NGC 4395 using archived radio observations made with the Very Large Array (VLA) at the wavelengths of 3.5 cm, 6 ...
Vukotić B. +3 more
doaj +1 more source