Pith. Sign in

RECORD

On the fundamental dichotomy in the local radio-AGN population: accretion, evolution, and host galaxy properties

PaperPDF from arXiv

data files

Paper breakdownThe authors' claims, conditions and measurements, as JSON Signed receiptProof this review has not been altered
X Bluesky LinkedIn Reddit Hacker News
P. N. Best (IfA Edinburgh), T. M. Heckman (Johns Hopkins)

Cosmology and Nongalactic Astrophysics · Submitted 11 Jan 2012

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim These results offer strong support to the picture in which HERGs are fuelled at high rates through radiative accretion disks by cold gas, perhaps from mergers and interactions, while LERGs are fuelled via radiatively inefficient flows at low accretion rates, often by gas associated with the hot X-ray haloes of their host galaxy/cluster, as part of a radio-AGN feedback loop (abridged).

how it is stated · hedged possibility 0.73 read the record →

Comment (0) Read on arXiv ↗
Cite ▾
arXiv ID1201.2397 (version 1)
Pith IDARBZS2U6, Pith's permanent record of this paper and its review
CitationP. N. Best (IfA Edinburgh), T. M. Heckman (Johns Hopkins). "On the fundamental dichotomy in the local radio-AGN population: accretion, evolution, and host galaxy properties." arXiv:1201.2397 (2012). https://pith.science/paper/ARBZS2U6
Claim paper

The compiled record

The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Open the compiled record

Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 7,391 input tokens, $0.0003 reported.

What the abstract itself states, as probabilities: claims first 0.02 · states limitation 0.22 · human participants 0.01 · controlled comparison 0.23 · randomized assignment 0.01 · states quantitative result 0.98 · compares with prior results 0.21 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; .

A sample of 18286 radio-loud AGN is presented, constructed by combining the SDSS DR7 with the NVSS and FIRST radio surveys. Using this sample, the differences between `high-excitation' (or `quasar-mode'; HERG) and `low-excitation' (`radio-mode'; LERG) radio galaxies are investigated. A primary difference is the distinct nature of the Eddington-scaled accretion rate onto their central black holes: HERGs typically have accretion rates between 1 and 10% of Eddington, whereas LERGs predominatly accrete at a rate below 1% Eddington. This is consistent with models where the population dichotomy is caused by a switch between radiatively efficient and inefficient accretion modes at low accretion rates. Local radio luminosity functions are derived separately for the two populations, showing that although LERGs dominate at low luminosity and HERGs above 1e26 W/Hz, examples of both classes are found at all radio luminosities. Using the V/Vmax test it is shown that the populations show differential cosmic evolution at fixed radio luminosity: HERGs evolve strongly at all luminosities, while LERGs show weak or no evolution. This suggests that the luminosity-dependent evolution of the radio luminosity function is driven, at least in part, by the changing relative contributions of these two populations with luminosity. The host galaxies of the sources are also distinct: HERGs are typically of lower stellar mass, with lower black hole masses, bluer colours and weaker 4000-Ang breaks indicating younger stellar populations. These results offer strong support to the picture in which HERGs are fuelled at high rates through radiative accretion disks by cold gas, perhaps from mergers and interactions, while LERGs are fuelled via radiatively inefficient flows at low accretion rates, often by gas associated with the hot X-ray haloes of their host galaxy/cluster, as part of a radio-AGN feedback loop (abridged).

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 A sample of 18286 radio-loud AGN is presented, constructed by combining the SDSS DR7 with the NVSS and FIRST radio surveys. method 0.79 0.91 0.02 asserted 1.00
s1 Using this sample, the differences between `high-excitation' (or `quasar-mode'; HERG) and `low-excitation' (`radio-mode'; LERG) radio galaxies are investigated. contribution 0.87 0.85 0.03 asserted 0.70
s2 A primary difference is the distinct nature of the Eddington-scaled accretion rate onto their central black holes: HERGs typically have accretion rates between 1 and 10% of Eddington, whereas LERGs predominatly accrete at a rate below 1% Eddington. result 1.00 0.80 0.22 asserted 1.00
s3 This is consistent with models where the population dichotomy is caused by a switch between radiatively efficient and inefficient accretion modes at low accretion rates. interpretation 1.00 0.16 0.17 hedged possibility 0.99
s4 Local radio luminosity functions are derived separately for the two populations, showing that although LERGs dominate at low luminosity and HERGs above 1e26 W/Hz, examples of both classes are found at all radio luminosities. result 1.00 0.96 0.08 asserted 1.00
s5 Using the V/Vmax test it is shown that the populations show differential cosmic evolution at fixed radio luminosity: HERGs evolve strongly at all luminosities, while LERGs show weak or no evolution. result 0.99 0.95 0.12 asserted 1.00
s6 This suggests that the luminosity-dependent evolution of the radio luminosity function is driven, at least in part, by the changing relative contributions of these two populations with luminosity. interpretation 1.00 0.78 0.16 hedged possibility 1.00
s7 The host galaxies of the sources are also distinct: HERGs are typically of lower stellar mass, with lower black hole masses, bluer colours and weaker 4000-Ang breaks indicating younger stellar populations. result 1.00 0.87 0.06 asserted 0.98
s8 These results offer strong support to the picture in which HERGs are fuelled at high rates through radiative accretion disks by cold gas, perhaps from mergers and interactions, while LERGs are fuelled via radiatively inefficient flows at low accretion rates, often by gas associated with the hot X-ray haloes of their host galaxy/cluster, as part of a radio-AGN feedback loop (abridged). interpretation 1.00 0.47 0.70 hedged possibility 0.73

What kind of paper the classifier reports this is: empirical study 0.99 · evidence from analysis of existing data 1.00.

What was examined, and what was not

sources read
  • arXiv listing abstract v1
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper
Original abstract

A sample of 18286 radio-loud AGN is presented, constructed by combining the SDSS DR7 with the NVSS and FIRST radio surveys. Using this sample, the differences between `high-excitation' (or `quasar-mode'; HERG) and `low-excitation' (`radio-mode'; LERG) radio galaxies are investigated. A primary difference is the distinct nature of the Eddington-scaled accretion rate onto their central black holes: HERGs typically have accretion rates between 1 and 10% of Eddington, whereas LERGs predominatly accrete at a rate below 1% Eddington. This is consistent with models where the population dichotomy is caused by a switch between radiatively efficient and inefficient accretion modes at low accretion rates. Local radio luminosity functions are derived separately for the two populations, showing that although LERGs dominate at low luminosity and HERGs above 1e26 W/Hz, examples of both classes are found at all radio luminosities. Using the V/Vmax test it is shown that the populations show differential cosmic evolution at fixed radio luminosity: HERGs evolve strongly at all luminosities, while LERGs show weak or no evolution. This suggests that the luminosity-dependent evolution of the radio luminosity function is driven, at least in part, by the changing relative contributions of these two populations with luminosity. The host galaxies of the sources are also distinct: HERGs are typically of lower stellar mass, with lower black hole masses, bluer colours and weaker 4000-Ang breaks indicating younger stellar populations. These results offer strong support to the picture in which HERGs are fuelled at high rates through radiative accretion disks by cold gas, perhaps from mergers and interactions, while LERGs are fuelled via radiatively inefficient flows at low accretion rates, often by gas associated with the hot X-ray haloes of their host galaxy/cluster, as part of a radio-AGN feedback loop (abridged).

Human review

How Pith checks papers → · Full audit of this paper →

References
How later papers used it

223 later papers cite it

Evidence: substantial. 201 of the citing papers share no author with it, and 59 of those carry a confident label from Pith's citation classifier.

Pith read 30 of the 638 citing sentences, choosing only those whose citation markers point at this paper alone, and wrote the paraphrases from them. The summary, the counts, the evidence level, the links and the quotes come from code; the summary counts the papers listed below. A later paper is listed under a label when Pith's citation classifier gives one of its sentences that label at probability 0.8 or more (0.95 for support), Pith's reading finds that the citing paper itself did it, and a second check confirms the paraphrase against the sentence. This section lists uses only. It does not list criticism or disagreement, so their absence here says nothing about how the paper has been received. Papers that share an author with this one are listed apart, under "By the same authors". A quote is the citing authors' own sentence, shown when their paper's licence is CC BY, CC BY-SA or CC0. JSON

Uses its method or tool 1 of 16 papers with this label
Uses its data or values 7 of 35 papers with this label
Compares with it 1 of 23 papers with this label
How the literature uses it

15 arXiv papers cite this in 41 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers whose main result relates to this one's

Found among the papers closest to this one by title and main claim. Pith's classifier compared each pair's main results and a second model family confirmed the relation; checked against two further families, shown conflicts agreed 118 times in 120 and shown same results 218 times in 239. The quoted sentence is the other paper's main claim.

States a conflicting result 1 paper
  • In contrast to previous work, we find that the HERGs and LERGs have very similar Eddington-scaled accretion rates; in particular we identify a population of very slowly accreting AGN that are formally classified as HERGs at these low radio luminosities, where separating into HERGs and LERGs possibly becomes redundant.

    MIGHTEE: the nature of the radio-loud AGN population · 0.86

Papers citing it · 30 sentences without a confident label

Uses its data or values 3 papers
  • The parent sample of radio-loud active galactic nuclei (RL AGN) used in this study is drawn from the catalog of [ref] , which was constructed by cross-matching the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7; [ref] ) spectroscopic galaxy sample with the NRAO VLA Sky Survey (NVSS; [ref] ) and the Faint Images of the Radio Sky at Twenty Centimeters survey (FIRST; [ref] ).

    When Jets Don't Quench: Near-Infrared H$_{2}$ in Star Forming Low-Excitation Radio Galaxies · Parent Radio AGN Sample · 0.93

  • We also used radio-loud AGN identified from the catalogue of [ref] http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=J/MNRAS/421/1569http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=J/MNRAS/421/1569.

    An increase in black hole activity in galaxies with kinematically misaligned gas · Cross matching with AGN catalogues · 0.99

  • For example, the availability of radio surveys with the VLA and large-area optical surveys such as the SDSS led to the compilation of $∼$18000 radio sources upto redshifts of $∼$0.3 and stronger than $∼$5 mJy at 1400 MHz [ref] .

    Compact steep-spectrum and peaked-spectrum radio sources · The FR0 sources · 0.85

Cites it as support 1 paper
  • This model is supported by observations in which the HERG/LERG classification, black hole mass and bolometric radiative luminosity of large samples of sources have been measured [ref] and is consistent with expectations from theoretical disk models [ref] .

    Radio galaxies and feedback from AGN jets · Unified models and accretion modes · 0.99

Cites it as background 3 papers

Discussion

Know something about this paper? Leave a comment, or highlight any passage above to comment on it.