An Analysis of the Broadband (22-3900 MHz) Radio Spectrum of HB 3 (G132.7+1.3): The Detection of Thermal Radio Emission from an Evolved Supernova Remnant?

2007 ◽  
Vol 655 (1) ◽  
pp. L41-L44 ◽  
Author(s):  
D. Urošević ◽  
T. G. Pannuti ◽  
D. Leahy
Keyword(s):  
Radio Emission ◽  
Supernova Remnant ◽  
Radio Spectrum ◽  
Thermal Radio ◽  
Thermal Radio Emission

scholarly journals Murchison Widefield Array detection of steep-spectrum, diffuse, non-thermal radio emission within Abell 1127

2020 ◽  
Vol 37 ◽  
Author(s):  
S. W. Duchesne ◽  
M. Johnston-Hollitt ◽  
Z. Zhu ◽  
R. B. Wayth ◽  
J. L. B. Line
Keyword(s):  
Radio Emission ◽  
Galaxy Clusters ◽  
Phase Ii ◽  
Thermal Emission ◽  
Low Frequency ◽  
Radio Spectrum ◽  
Discrete Source ◽  
Thermal Radio ◽  
Thermal Radio Emission ◽  
Murchison Widefield Array

Abstract Diffuse, non-thermal emission in galaxy clusters is increasingly being detected in low-frequency radio surveys and images. We present a new diffuse, steep-spectrum, non-thermal radio source within the cluster Abell 1127 found in survey data from the Murchison Widefield Array (MWA). We perform follow-up observations with the ‘extended’ configuration MWA Phase II with improved resolution to better resolve the source and measure its low-frequency spectral properties. We use archival Very Large Array S-band data to remove the discrete source contribution from the MWA data, and from a power law model fit we find a spectral index of –1.83±0.29 broadly consistent with relic-type sources. The source is revealed by the Giant Metrewave Radio Telescope at 150 MHz to have an elongated morphology, with a projected linear size of 850 kpc as measured in the MWA data. Using Chandra observations, we derive morphological estimators and confirm quantitatively that the cluster is in a disturbed dynamical state, consistent with the majority of phoenices and relics being hosted by merging clusters. We discuss the implications of relying on morphology and low-resolution imaging alone for the classification of such sources and highlight the usefulness of the MHz to GHz radio spectrum in classifying these types of emission. Finally, we discuss the benefits and limitations of using the MWA Phase II in conjunction with other instruments for detailed studies of diffuse, steep-spectrum, non-thermal radio emission within galaxy clusters.

scholarly journals G17.8+16.7: A New Supernova Remnant

2021 ◽  
Author(s):  
M Araya ◽  
N Hurley-Walker ◽  
S Quirós-Araya
Keyword(s):  
Radio Emission ◽  
Supernova Remnant ◽  
Gamma Ray ◽  
Galactic Plane ◽  
Source Parameters ◽  
Radio Data ◽  
Circular Shape ◽  
Thermal Radio ◽  
Thermal Radio Emission ◽  
Multi Wavelength

Abstract Non-thermal radio emission is detected in the region of the gamma-ray source FHES J1723.5 − 0501. The emission has an approximately circular shape 0.8○ in diameter. The observations confirm its nature as a new supernova remnant, We derive constraints on the source parameters using the radio data and gamma-ray observations of the region. The distance to the object is possibly in the range 1.4–3.5 kpc. An SNR age of the order of 10 kyr is compatible with the radio and GeV features, but an older or younger SNR cannot be ruled out. A simple one-zone leptonic model naturally explains the multi-wavelength non-thermal fluxes of the source at its location outside the Galactic plane.

Resonance effects in thermal radio emission of water surface

1986 ◽  
Vol 29 (4) ◽  
pp. 279-283 ◽  
Author(s):  
V. E. Gershenzon ◽  
V. G. Irisov ◽  
Yu. G. Trokhimovskii ◽  
V. S. �tkin
Keyword(s):  
Radio Emission ◽  
Water Surface ◽  
Resonance Effects ◽  
Thermal Radio ◽  
Thermal Radio Emission

scholarly journals Non-thermal radio emission from O-type stars

2007 ◽  
Vol 464 (2) ◽  
pp. 701-708 ◽  
Author(s):  
R. Blomme ◽  
M. De Becker ◽  
M. C. Runacres ◽  
S. Van Loo ◽  
D. Y. A. Setia Gunawan
Keyword(s):  
Radio Emission ◽  
Thermal Radio ◽  
Thermal Radio Emission

scholarly journals Erratum: Constraining the nature of DG Tau A's thermal and non-thermal radio emission

2018 ◽  
Vol 483 (3) ◽  
pp. 4085-4085
Author(s):  
S J D Purser ◽  
R E Ainsworth ◽  
T P Ray ◽  
D A Green ◽  
A M Taylor ◽  
...  
Keyword(s):  
Radio Emission ◽  
Thermal Radio ◽  
Thermal Radio Emission

scholarly journals Non-thermal radio emission in Wolf-Rayet stars: is binarity a pre-requisite?

1999 ◽  
Vol 193 ◽  
pp. 348-349
Author(s):  
Sean M. Dougherty
Keyword(s):  
Radio Emission ◽  
Spectral Index ◽  
Thermal Emission ◽  
Radio Observations ◽  
Thermal Radio ◽  
Thermal Radio Emission ◽  
Thermal Emitters

Radio observations of Wolf-Rayet stars currently available in the literature are examined to determine whether binarity is a common feature of WR systems with non-thermal emission. Among 24 stars with observed spectral index values, seven are definite non-thermal emitters, and six others possibly have composite thermal/non-thermal spectra. Stellar companions have been identified in 71% of the non-thermal emitters, strongly supporting a link between non-thermal emission and binarity.

scholarly journals The nearby extreme accretion and feedback system PDS 456: finding a complex radio-emitting nucleus

2020 ◽  
Vol 500 (2) ◽  
pp. 2620-2626
Author(s):  
Jun Yang ◽  
Zsolt Paragi ◽  
Emanuele Nardini ◽  
Willem A Baan ◽  
Lulu Fan ◽  
...  
Keyword(s):  
Black Hole ◽  
Radio Emission ◽  
High Speed ◽  
Feedback System ◽  
Emission Region ◽  
Starburst Galaxy ◽  
Massive Black Hole ◽  
Star Forming ◽  
Thermal Radio ◽  
Thermal Radio Emission

ABSTRACT When a black hole accretes close to the Eddington limit, the astrophysical jet is often accompanied by radiatively driven, wide-aperture and mildly relativistic winds. Powerful winds can produce significant non-thermal radio emission via shocks. Among the nearby critical accretion quasars, PDS 456 has a very massive black hole (about 1 billion solar masses), shows a significant star-forming activity (about 70 solar masses per year), and hosts exceptionally energetic X-ray winds (power up to 20 per cent of the Eddington luminosity). To probe the radio activity in this extreme accretion and feedback system, we performed very long baseline interferometric (VLBI) observations of PDS 456 at 1.66 GHz with the European VLBI Network and the enhanced Multi-Element Remotely Linked Interferometry Network. We find a rarely seen complex radio-emitting nucleus consisting of a collimated jet and an extended non-thermal radio emission region. The diffuse emission region has a size of about 360 pc and a radio luminosity about three times higher than that of the nearby extreme starburst galaxy Arp 220. The powerful nuclear radio activity could result either from a relic jet with a peculiar geometry (nearly along the line of sight) or more likely from diffuse shocks formed naturally by the existing high-speed winds impacting on high-density star-forming regions.

scholarly journals Numerical simulations of unbounded cyclotron-maser emissions

2013 ◽  
Vol 79 (6) ◽  
pp. 999-1001 ◽  
Author(s):  
DAVID C. SPEIRS ◽  
S. L. McCONVILLE ◽  
K. M. GILLESPIE ◽  
A. D. R. PHELPS ◽  
K. RONALD
Keyword(s):  
Radio Emission ◽  
Numerical Simulations ◽  
Source Region ◽  
Radio Emissions ◽  
Cyclotron Maser ◽  
Thermal Radio ◽  
Thermal Radio Emission ◽  
Electron Cyclotron Masers ◽  
Coupling Characteristics ◽  
Significant Bearing

AbstractNumerical simulations have been conducted to study the spatial growth rate and emission topology of the cyclotron-maser instability responsible for stellar/planetary auroral magnetospheric radio emission and intense non-thermal radio emission in other astrophysical contexts. These simulations were carried out in an unconstrained geometry, so that the conditions existing within the source region of some natural electron cyclotron masers could be more closely modelled. The results have significant bearing on the radiation propagation and coupling characteristics within the source region of such non-thermal radio emissions.

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