scholarly journals A Double Radio Source with a Wide Component Separation

1965 ◽  
Vol 18 (6) ◽  
pp. 671 ◽  
Author(s):  
FF Gardner ◽  
JG Bolton
Keyword(s):  
Radio Source ◽  
Angular Separation ◽  
Component Separation ◽  
The Other ◽  
Radio Sources ◽  
Physical Separation ◽  
Component Size ◽  
Double Radio Source ◽  
Parent Galaxy

Moffet (1964, 1965) has recently drawn attention to two double radio sources which have unusually large ratios of separation to component size. One of these, 3C 33, an interferometric double, has an angular separation of 250". and a component size of 16", giving a ratio of 16 : 1. The distance of the parent galaxy is such that the physical separation of the two components is at least 200 kpc. The other double consists of the sources 3C 343 and 3C 343�1 (revised Third Cambridge Catalogue

scholarly journals The Impact of the Early Stages of Radio Source Evolution on the ISM of the Host Galaxies

2003 ◽  
Vol 20 (1) ◽  
pp. 129-133 ◽  
Author(s):  
R. Morganti ◽  
C. N. Tadhunter ◽  
T. A. Oosterloo ◽  
J. Holt ◽  
A. Tzioumis ◽  
...  
Keyword(s):  
Radio Source ◽  
Radio Galaxy ◽  
Optical Emission ◽  
The Other ◽  
Emission Lines ◽  
Radio Sources ◽  
Host Galaxies ◽  
Cygnus A ◽  
Intermediate Size ◽  
The Impact

AbstractThe study of both neutral and ionised gas in young radio sources is providing key information on the effect the radio plasma has on the ISM of these objects. We present results obtained for the compact radio sources PKS 1549–79, 4C 12.50 and PKS 1814–63 and for the intermediate-size radio galaxy 3C 459. At least in the first two, low ionisation optical emission lines and HI absorption appear to be associated with the extended, but relatively quiescent, dusty cocoon surrounding the nucleus. The [OIII] lines are, on the other hand, mostly associated with the region of interaction between the radio plasma and the ISM, indicating a fast outflow from the centre. A case of fast outflow (up to ∼1000 km s-1) is also observed in HI in the radio source 4C 12.50. As the radio source evolves, any obscuring material along the radio axis is swept aside until, eventually, cavities (of the same kind as observed e.g. in Cygnus A) are hollowed out on either side of the nucleus. We may witness this phase in the evolution of a radio source in the radio galaxy 3C 459.

Polarization of extragalactic radio sources: CMB foregrounds and telescope calibration issues

2016 ◽  
Vol 25 (11) ◽  
pp. 1640009 ◽  
Author(s):  
Marcella Massardi ◽  
Vincenzo Galluzzi ◽  
Rosita Paladino ◽  
Carlo Burigana
Keyword(s):  
Cosmic Microwave Background ◽  
Radio Source ◽  
High Redshift ◽  
The Other ◽  
Radio Sources ◽  
Polarization Rotation ◽  
Microwave Background ◽  
Extragalactic Radio Sources ◽  
Systematic Effects ◽  
The One

Radio source observations play important roles in polarimetric cosmological studies. On the one hand, they constitute the main foregrounds for cosmic microwave background (CMB) radiation on scales smaller than 30 arcmin up to 100 GHz, on the other they can be used as targets for validation of products of polarimetric experiments dedicated to cosmology. Furthermore, extragalactic high-redshift sources have been used for cosmic polarization rotation (CPR) investigation. In this paper, we will discuss the support to cosmological studies from ground-based polarimetric observations in the radio and millimetric wavelength bands. Most of the limits to accuracy improvements arise from systematic effects and low calibration quality. We will discuss some details of interferometric calibration procedures and show some of the perspectives that the Atacama large millimeter array (ALMA) could offer for CPR studies.

The Polarization of Metre-Wave Solar Emission

1980 ◽  
Vol 4 (1) ◽  
pp. 56-59 ◽  
Author(s):  
S. Suzuki ◽  
K. V. Sheridan
Keyword(s):  
Radio Source ◽  
Circular Polarization ◽  
Magnetic Structure ◽  
Magnetic Loop ◽  
The Other ◽  
Type I ◽  
Double Radio Source

Sources of the Type I storms are thought to lie on closed magnetic loop systems above bipolar sunspots. Usually one sunspot is stronger than the other in the bipolar magnetic structure, and accordingly only one radio source associated with the stronger sunspot is usually observed. Occasionally however a double radio source is observed in conjunction with the bipolar sunspots. In such a case the double radio source should be intrinsically bipolar, viz. the two components should emit opposite senses of circular polarization (in this paper we use the word polarity for simplicity).

scholarly journals VLBA+GBT observations of the COSMOS field and radio source counts at 1.4 GHz

2018 ◽  
Vol 616 ◽  
pp. A128 ◽  
Author(s):  
N. Herrera Ruiz ◽  
E. Middelberg ◽  
A. Deller ◽  
V. Smolčić ◽  
R. P. Norris ◽  
...  
Keyword(s):  
Radio Source ◽  
Flux Density ◽  
Lower Limit ◽  
High Sensitivity ◽  
Host Galaxy ◽  
Radio Sources ◽  
Source Population ◽  
Star Forming ◽  
Brightness Temperatures ◽  
Long Baseline

We present very long baseline interferometry (VLBI) observations of 179 radio sources in the COSMOS field with extremely high sensitivity using the Green Bank Telescope (GBT) together with the Very Long Baseline Array (VLBA) (VLBA+GBT) at 1.4 GHz, to explore the faint radio population in the flux density regime of tens of μJy. Here, the identification of active galactic nuclei (AGN) is based on the VLBI detection of the source, meaning that it is independent of X-ray or infrared properties. The milli-arcsecond resolution provided by the VLBI technique implies that the detected sources must be compact and have large brightness temperatures, and therefore they are most likely AGN (when the host galaxy is located at z ≥ 0.1). On the other hand, this technique only allows us to positively identify when a radio-active AGN is present, in other words, we cannot affirm that there is no AGN when the source is not detected. For this reason, the number of identified AGN using VLBI should be always treated as a lower limit. We present a catalogue containing the 35 radio sources detected with the VLBA+GBT, ten of which were not previously detected using only the VLBA. We have constructed the radio source counts at 1.4 GHz using the samples of the VLBA and VLBA+GBT detected sources of the COSMOS field to determine a lower limit for the AGN contribution to the faint radio source population. We found an AGN contribution of >40−75% at flux density levels between 150 μJy and 1 mJy. This flux density range is characterised by the upturn of the Euclidean-normalised radio source counts, which implies a contribution of a new population. This result supports the idea that the sub-mJy radio population is composed of a significant fraction of radio-emitting AGN, rather than solely by star-forming galaxies, in agreement with previous studies.

scholarly journals High Frequency Peakers

2003 ◽  
Vol 20 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Daniele Dallacasa
Keyword(s):  
Radio Source ◽  
High Frequency ◽  
Peak Frequency ◽  
Source Size ◽  
Host Galaxy ◽  
Radio Sources ◽  
Inner Region

AbstractThere is quite a clear anticorrelation between the intrinsic peak frequency and the overall radio source size in compact steep spectrum (CSS) and gigahertz peaked spectrum (GPS) radio sources. This feature is interpreted in terms of synchrotron self-absorption (although free–free absorption may play a role as well) of the radiation emitted by a small radio source which is growing within the inner region of the host galaxy. This leads to the hypothesis that these objects are young and that the radio source is still developing/expanding within the host galaxy itself.Very young radio sources must have the peak in their radio spectra occurring above a few tens of gigahertz, and for this reason they are termed high frequency peakers (HFPs). These newly born radio sources must be very rare given that they spend very little time in this stage. Ho = 100 km s−1 Mpc−1 and qo = 0.5 are used throughout this paper.

L'échec des clôtures du dialogue dans les comédies de Plaute

2005 ◽  
Vol 9 (2) ◽  
Author(s):  
Sophie Roesch
Keyword(s):  
The Other ◽  
Physical Separation

SummaryThe closing of an exchange requires cooperation from both speakers. When someone wants to end the dialog, whereas the other speaker doesn’t, conflict necessarily arises. The speaker reluctant to end the dialog is going to use every possible means to delay the closing, before the physical separation takes place. To prevent the closing, a speaker will usually use questions or orders, which compel the other to respond and prolong the exchange. He may also resort to summons (audin, sed quid ais) and addi- tions (thanks to the connective particles et, at and sed), or keep on speaking, without paying heed to the other speaker’s desire to leave. Whatever means the speaker may use to hinder the closing, the frequency of such passages in Plautus’ comedies is probably due to their comic effect.

scholarly journals Oh Observations in the Directions of Galactic Thermal Sources

1967 ◽  
Vol 20 (4) ◽  
pp. 407 ◽  
Author(s):  
RX McGee ◽  
FF Gardner ◽  
BJ Robinson
Keyword(s):  
Linear Polarization ◽  
The Other ◽  
Radio Sources ◽  
Line Radiation ◽  
Thermal Sources ◽  
Made In

A survey for the hydroxyl line radiation has been made in the directions of 30 radio sources (most of them thermal) with the 210 ft telescope of beamwidth 12'� 2 and the multichannel line receiver of bandwidths 10 and 37 kHz. The line at frequency 1665�401 MHz was observed for all sources and the other three lines at 1612, 1667, and 1720 MHz were observed for 10 of the more important sources. The latter were investigated for circular and linear polarization.

Open Versus Endoscopic Component Separation: How to Choose One or the Other

2012 ◽  
pp. 463-473
Author(s):  
Eduardo Parra-Davila ◽  
Juan J. Diaz-Hernandez ◽  
Carlos M. Ortiz-Ortiz
Keyword(s):  
Component Separation ◽  
The Other ◽  
Open Versus
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