scholarly journals The Spiral Host Galaxy of the Double Radio Source 0313?1921

2006 ◽  
Vol 132 (6) ◽  
pp. 2233-2242 ◽  
Author(s):  
William C. Keel ◽  
Raymond E. White III ◽  
Frazer N. Owen ◽  
Michael J. Ledlow
Keyword(s):  
Radio Source ◽  
Host Galaxy ◽  
Double Radio Source

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.

Anomalous component motion in the mas double radio source, 0646+600

1994 ◽  
pp. 367-368
Author(s):  
Chidi E. Akujor ◽  
Richard W. Porcas
Keyword(s):  
Radio Source ◽  
Anomalous Component ◽  
Double Radio Source ◽  
Component Motion

scholarly journals Properties of Radio Source Host Galaxies

2003 ◽  
Vol 20 (1) ◽  
pp. 6-11 ◽  
Author(s):  
Wim de Vries
Keyword(s):  
Radio Source ◽  
Large Scale ◽  
Radio Galaxy ◽  
Host Galaxy ◽  
Host Galaxies ◽  
State Of Affairs

AbstractA brief overview of the current radio source host galaxy state of affairs is given. All the evidence appears to point towards a scenario in which the young radio source expands through the host galaxy on timescales of 105–106 yr, before it ends its life as a large scale FR II radio galaxy. The place and role of the quasars in this evolutionary picture is unclear, however, and remains an issue of debate.

Interactions between the Abell 2597 central radio source and dense gas in its host galaxy

2002 ◽  
Vol 46 (2-7) ◽  
pp. 149-153 ◽  
Author(s):  
Anton M. Koekemoer ◽  
Christopher P. O’Dea ◽  
Craig L. Sarazin ◽  
Brian R. McNamara ◽  
Megan Donahue ◽  
...  
Keyword(s):  
Radio Source ◽  
Host Galaxy ◽  
Dense Gas

Anomalous component motion in the mas double radio source, 0646+600

1994 ◽  
Vol 216 (1-2) ◽  
pp. 367-368
Author(s):  
Chidi E. Akujor ◽  
Richard W. Porcas
Keyword(s):  
Radio Source ◽  
Anomalous Component ◽  
Double Radio Source ◽  
Component Motion

C 343, a Double Radio Source with Very Wide Component Separation.

1965 ◽  
Vol 141 ◽  
pp. 1580 ◽  
Author(s):  
Alan T. Moffet
Keyword(s):  
Radio Source ◽  
Component Separation ◽  
Double Radio Source

Scorpius X-1 - an evolving double radio source

1986 ◽  
Vol 311 ◽  
pp. 805 ◽  
Author(s):  
B. J. Geldzahler ◽  
E. B. Fomalont
Keyword(s):  
Radio Source ◽  
Double Radio Source

Formation of double radio source structures and superluminal expansion

1977 ◽  
Vol 216 ◽  
pp. L1 ◽  
Author(s):  
W. A. Christiansen ◽  
J. S. Scott
Keyword(s):  
Radio Source ◽  
Double Radio Source ◽  
Superluminal Expansion
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