scholarly journals The high brightness temperature of B0529+483 revealed by RadioAstron and implications for interstellar scattering

2017 ◽  
Vol 474 (3) ◽  
pp. 3523-3534 ◽  
Author(s):  
S V Pilipenko ◽  
Y Y Kovalev ◽  
A S Andrianov ◽  
U Bach ◽  
S Buttaccio ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
High Brightness ◽  
Interstellar Scattering

Absorption in Radio Sources of High Brightness Temperature

Nature ◽  
1963 ◽  
Vol 200 (4901) ◽  
pp. 56-57 ◽  
Author(s):  
P. J. S. WILLIAMS
Keyword(s):  
Brightness Temperature ◽  
Radio Sources ◽  
High Brightness

scholarly journals Space-VLBI observations of OH masers

2002 ◽  
Vol 206 ◽  
pp. 105-111 ◽  
Author(s):  
Vyacheslav I. Slysh ◽  
Maxim A. Voronkov ◽  
Irina E. Val'tts ◽  
Victor Migenes ◽  
K.M. Shibata ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Lower Limit ◽  
Radio Telescope ◽  
Angular Resolution ◽  
Main Line ◽  
Radio Telescopes ◽  
Space Radio Telescope ◽  
Vlbi Observations ◽  
Interstellar Scattering

We report on the first space-VLBI observations of the OH masers in two main-line OH transitions at 1665 and 1667 MHz. The observations involved the space radio telescope on board the Japanese satellite HALCA and an array of ground radio telescopes. The maps of the maser region and images of individual maser spots were produced with an angular resolution of 1 mas, which is several times higher than the angular resolution available on the ground. The maser spots were only partly resolved and a lower limit to the brightness temperature 6 × 1012 K was obtained. The masers seem to be located in the direction of low interstellar scattering.

A Gyro-Synchrotron Maser in the Solar Corona?

1978 ◽  
Vol 3 (3) ◽  
pp. 231-233 ◽  
Author(s):  
D. B. Melrose ◽  
S. M. White
Keyword(s):  
Synchrotron Radiation ◽  
Solar Corona ◽  
Brightness Temperature ◽  
Early Phase ◽  
Relativistic Electrons ◽  
High Brightness ◽  
Brightness Temperatures ◽  
Type Iv ◽  
Alternative Suggestion ◽  
Lower Frequencies

Stewart (1978) has reported four moving type IV bursts observed with the Culgoora radio heliograph at 43, 80 and 160 MHz. After an early phase, the brightness temperatures of the observed bursts decreased with increasing frequency and with time. The highest brightness temperature observed at 43 MHz was 1010K, and it seems that the brightness temperature would have been still higher at even lower frequencies. Existing theoretical ideas on moving type IV bursts are based on data (at 80 MHz primarily) which included no brightness temperatures in excess of 109K. the accepted interpretation involved gyro-synchrotron radiation from mildly relativistic electrons (energies ≈ 100 keV); reabsorption by the electrons themselves restricts the brightness temperature to less than about 100 keV ≈ 109K (Wild and Smerd 1972, Dulk 1973). Stewart’s (1978) new data at 43 MHz require that this accepted interpretation be modified; he has suggested that higher energy electrons are involved. An alternative suggestion is explored here, namely that the absorption might be negative. In other words, the high brightness temperatures observed could be due to a gyro-synchrotron maser involving electrons with energies of about 100 keV.

scholarly journals An Update on Radio Supernovae

1998 ◽  
Vol 164 ◽  
pp. 357-358 ◽  
Author(s):  
Schuyler D. Van Dyk ◽  
Richard A. Sramek ◽  
Kurt W. Weiler ◽  
Marcos J. Montes ◽  
Nino Panagia
Keyword(s):  
Synchrotron Radiation ◽  
Radio Emission ◽  
Brightness Temperature ◽  
Power Law ◽  
Progress Report ◽  
Light Curves ◽  
High Brightness ◽  
Turn On ◽  
Distance Indicators ◽  
Circumstellar Environment

AbstractThe radio emission from supernovae (SNe) is nonthermal synchrotron radiation of high brightness temperature, with a “turn-on” delay at longer wavelengths, power-law decline after maximum with index β, and spectral index α asymptotically decreasing with time to a final, optically thin value. Radio supernovae (RSNe) are best described by the Chevalier (1982) “mini-shell” model, with modifications by Weiler et al. (1990). RSNe observations provide a valuable probe of the SN circumstellar environment and constraints on progenitor masses. We present a progress report on a number of recent RSNe, as well as on new behavior from RSNe 1979C and 1980K, and on RSNe as potential distance indicators. In particular, we present updated radio light curves for SN 1993J in M81.

scholarly journals DETECTION OF A HIGH BRIGHTNESS TEMPERATURE RADIO CORE IN THE ACTIVE-GALACTIC-NUCLEUS-DRIVEN MOLECULAR OUTFLOW CANDIDATE NGC 1266

2013 ◽  
Vol 779 (2) ◽  
pp. 173 ◽  
Author(s):  
Kristina Nyland ◽  
Katherine Alatalo ◽  
J. M. Wrobel ◽  
Lisa M. Young ◽  
Raffaella Morganti ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Active Galactic Nucleus ◽  
High Brightness ◽  
Molecular Outflow

scholarly journals UNEXPECTED HIGH BRIGHTNESS TEMPERATURE 140 PC FROM THE CORE IN THE JET OF 3C 120

2010 ◽  
Vol 712 (2) ◽  
pp. L160-L164 ◽  
Author(s):  
Mar Roca-Sogorb ◽  
José L. Gómez ◽  
Iván Agudo ◽  
Alan P. Marscher ◽  
Svetlana G. Jorstad
Keyword(s):  
Brightness Temperature ◽  
High Brightness ◽  
The Core ◽  
3C 120

scholarly journals The Mechanism Responsible for 'Shadow' Type III Solar Radio Bursts. I. Absorption due to Langmuir Turbulence

1974 ◽  
Vol 27 (2) ◽  
pp. 259 ◽  
Author(s):  
DB Melrose
Keyword(s):  
Brightness Temperature ◽  
Solar Radio ◽  
Second Harmonic ◽  
Langmuir Turbulence ◽  
Absorption Mechanism ◽  
Solar Radio Bursts ◽  
High Brightness ◽  
Type Iii ◽  
Narrow Frequency Range ◽  
Absorption Features

The hypothesis is advanced that for 'shadow' type III solar radio events (absorption features with drift rates and bandwidths typical of type III bursts or U-bursts) the absorption mechanism involves Langmuir turbulence, such absorption being the inverse of either fundamental (I = J;,) or second harmonic (f = 2/p) plasma emission. The theory for both absorption processes is developed and applied to shadow type III events with the following results: (1) the predicted absorption is confined to a very narrow frequency range (fl.I/ I ~ 10- 3); (2) effective absorption requires an energy density in Langmuir turbulence (with phase speeds ~tc) in excess of 10-9 ergcm- 3 for the fundamental and in excess of 3 x 10-6 ergcm- 3 for the second harmonic; (3) the brightness of the background source must exceed 109 and 1016 K for absorption at the fundamental and second harmonic respectively. Comparison of the theory with the properties of an event discussed by Kai (1973) leads to the conclusions: (1) absorption at the second harmonic is unacceptable because of the high brightness temperature required; (2) to explain the observed bandwidth in terms of absorption at the fundamental, the absorbing region and the background source must overlap in height; (3) to explain the observed reduction in brightness temperature requires that the initial brightness temperature exceed 5�5 X 109 K (the observed value was 109 K).

scholarly journals AGN Feedback Driven Molecular Outflow in NGC 1266

2012 ◽  
Vol 8 (S290) ◽  
pp. 175-176
Author(s):  
K. Alatalo ◽  
K. E. Nyland ◽  
G. Graves ◽  
S. Deustua ◽  
J. Wrobel ◽  
...  
Keyword(s):  
Star Formation ◽  
Brightness Temperature ◽  
Significant Role ◽  
Molecular Gas ◽  
High Brightness ◽  
Continuum Source ◽  
Low Level ◽  
Molecular Outflow ◽  
Field Galaxy ◽  
Red Sequence

AbstractNGC 1266 is a nearby field galaxy observed as part of the ATLAS3D survey (Cappellari et al. 2011). NGC 1266 has been shown to host a compact (< 200 pc) molecular disk and a mass-loaded molecular outflow driven by the AGN (Alatalo et al. 2011). Very Long Basline Array (VLBA) observations at 1.65 GHz revealed a compact (diameter < 1.2 pc), high brightness temperature continuum source most consistent with a low-level AGN origin. The VLBA continuum source is positioned at the center of the molecular disk and may be responsible for the expulsion of molecular gas in NGC 1266. Thus, the candidate AGN-driven molecular outflow in NGC 1266 supports the picture in which AGNs do play a significant role in the quenching of star formation and ultimately the evolution of the red sequence of galaxies.

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