scholarly journals Star Formation Rates in Lyman Break Galaxies: Radio Stacking of LBGs in the COSMOS Field and the Sub‐μJy Radio Source Population

2008 ◽  
Vol 689 (2) ◽  
pp. 883-888 ◽  
Author(s):  
C. L. Carilli ◽  
Nicholas Lee ◽  
P. Capak ◽  
E. Schinnerer ◽  
K.‐S. Lee ◽  
...  
Keyword(s):  
Star Formation ◽  
Radio Source ◽  
Source Population ◽  
Lyman Break Galaxies

scholarly journals Cosmological Studies from Radio Source Samples

2002 ◽  
Vol 199 ◽  
pp. 34-49 ◽  
Author(s):  
S. Rawlings
Keyword(s):  
Star Formation ◽  
Radio Source ◽  
Accretion Rate ◽  
Simple Calculation ◽  
Physical Models ◽  
Radio Sources ◽  
Source Population ◽  
Low Frequencies ◽  
Close Link ◽  
Redshift Surveys

I review some recent cosmological studies based on redshift surveys of radio sources selected at low frequencies. The accretion rate onto the central black hole is identified as the basis of a crude physical division of the low-frequency population into two sub-populations: the first comprises ‘Eddington-tuned’ (high accretion rate) quasars and their torus-hidden counterparts; the second comprises ‘starved quasars’ like M87. There exist remarkable similarities between the shapes and evolutionary behaviours of the luminosity functions of radio sources and radio-quiet quasars; all luminous AGN are ∼ 300—times rarer at epochs corresponding to z ∼ 0 than at z ∼ 2.5. I argue that any evidence that quasars were intrinsically rarer at z ∼ 5 than at z ∼ 2.5 is as yet both tentative and indirect. A simple calculation suggests that the radio source population has been over-looked as a potentially important contributor to the entropy budget of the Universe. A recent sub-mm survey of radio sources is used to demonstrate a connection between the events which trigger jets and intense bursts of star formation, and a close link between the histories of star formation and AGN activity is proposed. I discuss the aims and methods of future large redshift surveys of radio sources, emphasising the importance of dovetailing these with the development of robust physical models for radio sources and their epoch-dependent environments.

scholarly journals HerMES: disentangling active galactic nuclei and star formation in the radio source population

2015 ◽  
Vol 452 (4) ◽  
pp. 4111-4127 ◽  
Author(s):  
J. I. Rawlings ◽  
M. J. Page ◽  
M. Symeonidis ◽  
J. Bock ◽  
A. Cooray ◽  
...  
Keyword(s):  
Star Formation ◽  
Active Galactic Nuclei ◽  
Radio Source ◽  
Galactic Nuclei ◽  
Source Population

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 Spectroscopy of faint radio sources: the nature of the sub-mJy radio-source population

1993 ◽  
Vol 263 (1) ◽  
pp. 98-122 ◽  
Author(s):  
C. R. Benn ◽  
M. Rowan-Robinson ◽  
R. G. McMahon ◽  
T. J. Broadhurst ◽  
A. Lawrence
Keyword(s):  
Radio Source ◽  
Radio Sources ◽  
Source Population

scholarly journals The nature of the faint low-frequency radio source population

2017 ◽  
Vol 468 (1) ◽  
pp. 1156-1168 ◽  
Author(s):  
E. F. Ocran ◽  
A. R. Taylor ◽  
M. Vaccari ◽  
D. A. Green
Keyword(s):  
Radio Source ◽  
Low Frequency ◽  
Source Population

scholarly journals STAR FORMATION FROM DLA GAS IN THE OUTSKIRTS OF LYMAN BREAK GALAXIES ATz∼ 3

2011 ◽  
Vol 736 (1) ◽  
pp. 48 ◽  
Author(s):  
Marc Rafelski ◽  
Arthur M. Wolfe ◽  
Hsiao-Wen Chen
Keyword(s):  
Star Formation ◽  
Lyman Break Galaxies

scholarly journals Abell 1763 and its Cluster Feeding Filament: Constraints on the Intra-filament Medium

2010 ◽  
Vol 6 (S277) ◽  
pp. 309-312
Author(s):  
Louise O. V. Edwards ◽  
Dario Fadda
Keyword(s):  
Star Formation ◽  
Radio Source ◽  
Large Scale ◽  
Theoretical Models ◽  
Observational Constraints ◽  
Cosmological Simulations ◽  
Large Scale Structures ◽  
Scale Structures ◽  
Intermediate Density

AbstractGalaxies are found to inhabit a variety of environments. They are often found in pairs, groups, or clusters. Cosmological simulations predict that these clusters are connected on a larger scale by filaments, but because these large scale structures are so vast, and because they are of intermediate density, observational constraints on their properties are difficult to achieve. We find a large-scale filament in the Abell 1763-Abell 1770 superstructure, determine that the star-formation therein is enhanced, and uncover a bent double lobe radio source midway across the filament. From the bend of this AGN'a jets, we probe the density of the surrounding intra-filament medium (IFM), constrained to be between 1-20x10−29 gm/cm3. This density is consistent with direct probes of the IFM as well as theoretical models.

scholarly journals STAR FORMATION AND THE INTERSTELLAR MEDIUM INz>6 UV-LUMINOUS LYMAN-BREAK GALAXIES

2015 ◽  
Vol 807 (2) ◽  
pp. 180 ◽  
Author(s):  
Chris J. Willott ◽  
Chris L. Carilli ◽  
Jeff Wagg ◽  
Ran Wang
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Lyman Break Galaxies

scholarly journals The radio source population at high frequency: follow-up of the 15-GHz 9C survey

2004 ◽  
Vol 354 (2) ◽  
pp. 485-521 ◽  
Author(s):  
R. C. Bolton ◽  
G. Cotter ◽  
G. G. Pooley ◽  
J. M. Riley ◽  
E. M. Waldram ◽  
...  
Keyword(s):  
Radio Source ◽  
High Frequency ◽  
Source Population
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