Results 11 to 20 of about 38,529 (262)
Powerful Radio Sources in the Southern Sky. I. Optical Identifications
The Astrophysical Journal Supplement Series, 2023 Since the early sixties, our view of radio galaxies and quasars has been drastically shaped by discoveries made thanks to observations of radio sources listed in the Third Cambridge Catalog and its revised version (3CR).
F. Massaro +20 more
doaj +1 more source
A tool to understand emission mechanisms of blazars through their high‐energy gamma‐ray emission
Astronomische Nachrichten, Volume 344, Issue 6, August 2023., 2023 The blazar SED is characterized by two energy components. Evidence suggests that the low‐energy component is generated by the synchrotron mechanism, but for the high‐energy component, the mechanism is still uncertain. Two main models have been proposed to explain this emission. According to the leptonic model, a correlation between the emission of both
Mabel Osorio +3 more
wiley +1 more source
Multiwavelength astrophysics of the blazar OJ 287 and the project MOMO
Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023 Abstract We are carrying out the densest and longest multiyear, multiwavelength monitoring project of OJ 287 ever done. The project MOMO (Multiwavelength Observations and Modeling of OJ 287) covers wavelengths from the radio to the high‐energy regime. A few selected observations are simultaneous with those of the Event Horizon Telescope (EHT).
S. Komossa +21 more
wiley +1 more source
Extreme accretion events: TDEs and changing‐look AGN
Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023 Abstract We present a review of the topics of X‐ray stellar tidal disruption events (TDEs) and changing‐look active galactic nuclei (AGN). Stars approaching a supermassive black hole (SMBH) can be tidally disrupted and accreted. TDEs were first discovered in the X‐ray regime and appear as luminous, giant‐amplitude flares from inactive galaxies.
S. Komossa, D. Grupe
wiley +1 more source
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
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
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
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