On the redshift cut-off for flat-spectrum radio sources

Jarvis, Matt J.; Rawlings, Steve

doi:10.1046/j.1365-8711.2000.03801.x

Cited by 68 publications

(124 citation statements)

References 67 publications

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“…Since, on average, these are also the sources with the highest redshifts, this explains our relatively large error bars at z k 2. These results, however, are consistent, for example, with those of Dunlop & Peacock (1990) Jarvis & Rawlings (2000) and Arshakian et al (2006). Stronger evidence for a redshift cutoff comes from the evolution of the FSRQ luminosity function (x 6.2).…”

Section: Evolutionsupporting

confidence: 86%

The Deep X‐Ray Radio Blazar Survey. III. Radio Number Counts, Evolutionary Properties, and Luminosity Function of Blazars

Padovani

Giommi

Landt

et al. 2007

ApJ

113

174

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Our knowledge of the blazar surface densities and luminosity functions, which are fundamental parameters, relies still on samples at relatively high flux limits. As a result, our understanding of this rare class of active galactic nuclei is mostly based on relatively bright and intrinsically luminous sources. We present the radio number counts, evolutionary properties, and luminosity functions of the faintest blazar sample with basically complete ($95%) identifications. Based on the Deep X-Ray Radio Blazar Survey (DXRBS), it includes 129 flat-spectrum radio quasars (FSRQs) and 24 BL Lac objects down to a 5 GHz flux and power $50 mJy and $10 24 W Hz À1 , respectively, an order of magnitude improvement as compared to previously published (radio-selected) blazar samples. DXRBS FSRQs are seen to evolve strongly, up to redshift %1.5, above which high-power sources show a decline in their comoving space density. DXRBS BL Lac objects, on the other hand, do not evolve. High-energy and low-energy peaked BL Lac objects (HBLs and LBLs, respectively) share the same lack of cosmological evolution, which is at variance with some previous results. The observed luminosity functions are in good agreement with the predictions of unified schemes, with FSRQs getting close to their expected minimum power. Despite the fact that the large majority of our blazars are FSRQs, BL Lac objects are intrinsically $50 times more numerous. Finally, the relative numbers of HBLs and LBLs in the radio and X-ray bands are different from those predicted by the so-called blazar sequence and support a scenario in which HBLs represent a small minority (%10%) of all BL Lac objects.

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Section: Evolutionsupporting

confidence: 86%

The Deep X‐Ray Radio Blazar Survey. III. Radio Number Counts, Evolutionary Properties, and Luminosity Function of Blazars

Padovani

Giommi

Landt

et al. 2007

ApJ

113

174

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“…Such enhancement could indeed be triggered by the radio jets in gas-rich galaxies; however, there are very few radio galaxies at z > 5 (e.g. Jarvis & Rawlings 2000;Jarvis et al 2001a;Wall et al 2005;Rigby et al 2011Rigby et al , 2015. Therefore, it is important to understand at which epochs and under which conditions radio jets can efficiently boost the host galaxy star formation.…”

Section: The Dependence Of Star Formation On Radio Jetsmentioning

confidence: 99%

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

Kalfountzou

Stevens

Jarvis

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Several studies support the existence of a link between the AGN and star formation activity. Radio jets have been argued to be an ideal mechanism for direct interaction between the AGN and the host galaxy. A drawback of previous surveys of AGN is that they are fundamentally limited by the degeneracy between redshift and luminosity in flux-density limited samples. To overcome this limitation, we present far-infrared Herschel observations of 74 radio-loud quasars (RLQs), 72 radio-quiet quasars (RQQs) and 27 radio galaxies (RGs), selected at 0.9 < z < 1.1 which span over two decades in optical luminosity. By decoupling luminosity from evolutionary effects, we investigate how the star formation rate (SFR) depends on AGN luminosity, radio-loudness and orientation. We find that: 1) the SFR shows a weak correlation with the bolometric luminosity for all AGN sub-samples, 2) the RLQs show a SFR excess of about a factor of 1.4 compared to the RQQs, matched in terms of black hole mass and bolometric luminosity, suggesting that either positive radio-jet feedback or radio AGN triggering are linked to star-formation triggering and 3) RGs have lower SFRs by a factor of 2.5 than the RLQ sub-sample with the same BH mass and bolometric luminosity. We suggest that there is some jet power threshold at which radio-jet feedback switches from enhancing star formation (by compressing gas) to suppressing it (by ejecting gas). This threshold depends on both galaxy mass and jet power.

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“…Dunlop & Peacock, 1990). However Jarvis & Rawlings (2000) and Jarvis et al (2001c) highlighted how uncertain the form of this decline is for both flat-spectrum radio-loud quasars (which, crudely speaking, should reflect the overall evolution as it picks out favourably oriented sources from the underlying population) and also low-frequency-selected radio galaxies, due predominantly to difficulties in modelling the k−corrections, and the lack of available volume (and hence small numbers of sources) at high redshift for a given fluxdensity-limited sample. This uncertainty is also mirrored by the X-ray luminosity function (e.g.…”

Section: The High-luminosity Rlf: Friismentioning

confidence: 99%

The accretion history of the universe with the SKA

Jarvis

Rawlings

2004

New Astronomy Reviews

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In this paper we investigate how the Square Kilometre Array (SKA) can aid in determining the evolutionary history of active galactic nuclei (AGN) from redshifts z = 0 → 6. Given the vast collecting area of the SKA, it will be sensitive to both 'radio-loud' AGN and the much more abundant 'radio-quiet' AGN, namely the radio-quiet quasars and their 'Type-II' counterparts, out to the highest redshifts. Not only will the SKA detect these sources but it will also often be able to measure their redshifts via the Hydrogen 21 cm line in emission and/or absorption. We construct a complete radio luminosity function (RLF) for AGN, combining the most recent determinations for powerful radio sources with an estimate of the RLF for radio-quiet objects using the hard X-ray luminosity function of Ueda et al. (2003), including both Type-I and Type-II AGN. We use this complete RLF to determine the optimal design of the SKA for investigating the accretion history of the Universe for which it is likely to be a uniquely powerful instrument.

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On the redshift cut-off for flat-spectrum radio sources

Abstract: The definitive version is available at www.blackwell-synergy.com Copyright Blackwell Publishing DOI : 10.1046/j.1365-8711.2000.03801.

Cited by 68 publications

References 67 publications

The Deep X‐Ray Radio Blazar Survey. III. Radio Number Counts, Evolutionary Properties, and Luminosity Function of Blazars

The Deep X‐Ray Radio Blazar Survey. III. Radio Number Counts, Evolutionary Properties, and Luminosity Function of Blazars

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

The accretion history of the universe with the SKA

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