Results 51 to 60 of about 38,529 (262)

Deep Space Network Radio Science and Ground‐Based Planetary Radar in the Next Decade

open access: yesRadio Science, Volume 60, Issue 7, July 2025.
Abstract The Deep Space Network (DSN) has been a core operational element of NASA's crewed and robotic exploration of the Solar System since the early 1960s. The primary role of the DSN has been to acquire telemetry and navigation data, but over the years, its radiometric and radar capabilities have expanded to form a system for obtaining unique ...
R. S. Park   +13 more
wiley   +1 more source

An Extragalactic Widefield Search for Technosignatures with the Murchison Widefield Array

open access: yesThe Astrophysical Journal
It is common for surveys that are designed to find artificial signals generated by distant civilizations to focus on galactic sources. Recently, researchers have started focusing on searching for all other sources within the field observed, including the
C. D. Tremblay, S. J. Tingay
doaj   +1 more source

A Formation Mechanism for “Wrong Way” Radio Relics

open access: yesThe Astrophysical Journal Letters, 2023
Radio relics are typically found to be arc-like regions of synchrotron emission in the outskirts of merging galaxy clusters, bowing out from the cluster center.
Ludwig M. Böss   +2 more
doaj   +1 more source

Isolated Neutron Stars as Science Validation for XMM2ATHENA: Ensuring Robust Data for Future X‐Ray Astronomy

open access: yesAstronomische Nachrichten, Volume 346, Issue 3-4, March-May 2025.
ABSTRACT The discovery of radio‐quiet, x‐ray thermally emitting isolated neutron stars (XINSs) in the ROSAT All‐Sky Survey revealed a previously overlooked component of the neutron star population. Advancements in x‐ray instrumentation and the availability of deep, wide‐area optical surveys now enable us to explore XINSs at fainter x‐ray fluxes and ...
Adriana Mancini Pires   +11 more
wiley   +1 more source

SOURCES WITH LOW-FREQUENCY STEEPNESS SPECTRUM CONCERNING THE UNIFIED MODEL

open access: yesOdessa Astronomical Publications, 2012
Based on data of the data of the Grakovo catalogue of the extragalactic sources, detected at the decametre band with the UTR-2 radio telescope , it was established, that properties of radio sources with lowfrequency steepness of spectrum are in ...
A. P. Miroshnichenko
doaj   +1 more source

A Multiwavelength Investigation of Unidentified EGRET Sources

open access: yes, 2005
Statistical studies indicate that the 271 point sources of high-energy gamma rays belong to two groups: a Galactic population and an isotropic extragalactic population.
A.U. Landolt   +11 more
core   +2 more sources

DYNAMIC CHARACTERISTICS OF THE MAIN INDEXES OF SPACE WEATHER AND THEIR APPLICATION TO THE ANALYSIS MONITORING OBSERVATIONS FLUX DENSITIES OF POWER RADIO SOURCES ON RT <URAN-4>

open access: yesOdessa Astronomical Publications, 2012
On radio telescope "URAN-4" of the Odessa observatory of Radio-astronomical Institute during twenty five years (since 1987 till present) monitoring of power galactic and extragalactic radio sources on frequencies 25 and 20MHz has been carried out.
L. Guglya   +3 more
doaj   +1 more source

Extragalactic variable radio sources

open access: yesThe Astrophysical Journal, 1985
Radio emission from a plasmoid that expands in a nonspherically symmetric manner is analyzed. The properties of this model are compared with the results of Andrews et al. (1978) and Epstein et al. (1982) concerning the values of beta derived for standard (delayed) radio sources.
openaire   +1 more source

Young Extragalactic Radio Sources

open access: yes, 1999
Gigahertz Peaked Spectrum (GPS) sources and Compact Symmetric Objects (CSO) are selected in very different ways, but have a significant overlap in properties. Ever since their discovery it has been speculated that they are young objects, but only recently, strong evidence has been provided indicating that GPS sources and CSOs are indeed the young ...
Snellen, Ignas, Schilizzi, Richard
openaire   +2 more sources

Extragalactic Radio Sources and the WMAP Cold Spot

open access: yes, 2007
We detect a dip of 20-45% in the surface brightness and number counts of NVSS sources smoothed to a few degrees at the location of the WMAP cold spot. The dip has structure on scales of approximately 1-10 degrees.
Cabre A.   +5 more
core   +1 more source

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