The connection between radio-quiet active galactic nuclei and the high/soft state of X-ray binaries

Maccarone, Thomas J.; Gallo, Elena; Fender, R. P.

doi:10.1046/j.1365-8711.2003.07161.x

Cited by 175 publications

(199 citation statements)

References 66 publications

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“…This suggests that they might be radio galaxies, such as Fanaroff-Riley type I radio galaxies (FR Is), which are powered by low accretion rate AGNs (Chiaberge et al 1999;Ghisellini & Celotti 2001). At low accretion rates (L/L Edd < 0.01) AGNs are predicted to have radiatively inefficient accretion flows (RIAFs; Narayan et al 1995;Narayan & McClintock 2008), which are typically associated with strong radio outflows (Narayan et al 1995;Maccarone et al 2003). Indeed, one of the passive sources in our sample (#47 in Table 1) is a well known wide-angle-tail (WAT) radio source at z = 1.265 and shows strong extended radio jets (e.g., Bauer et al 2002).…”

Section: "Passive" Systemsmentioning

confidence: 99%

GOODS-Herschel: radio-excess signature of hidden AGN activity in distant star-forming galaxies

Moro

Alexander

Mullaney

et al. 2012

A&A

130

112

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Context. A tight correlation exists between far-infrared and radio emission for star-forming galaxies (SFGs), which seems to hold out to high redshifts (z ≈ 2). Any excess of radio emission over that expected from star formation processes is most likely produced by an active galactic nucleus (AGN), often hidden by large amounts of dust and gas. Identifying these radio-excess sources will allow us to study a population of AGN unbiased by obscuration and thus find some of the most obscured, Compton-thick AGN, which are in large part unidentified even in the deepest X-ray and infrared (IR) surveys. Aims. We present here a new spectral energy distribution (SED) fitting approach that we adopt to select radio-excess sources amongst distant star-forming galaxies in the GOODS-Herschel (North) field and to reveal the presence of hidden, highly obscured AGN. Methods. Through extensive SED analysis of 458 galaxies with radio 1.4 GHz and mid-IR 24 µm detections using some of the deepest Chandra X-ray, Spitzer and Herschel infrared, and VLA radio data available to date, we have robustly identified a sample of 51 radio-excess AGN (∼1300 deg −2 ) out to redshift z ≈ 3. These radio-excess AGN have a significantly lower far-IR/radio ratio (q < 1.68, 3σ) than the typical relation observed for star-forming galaxies (q ≈ 2.2). Results. We find that ≈45% of these radio-excess sources have a dominant AGN component in the mid-IR band, while for the remainders the excess radio emission is the only indicator of AGN activity. The presence of an AGN is also confirmed by the detection of a compact radio core in deep VLBI 1.4 GHz observations for eight of our radio-excess sources (≈16%; ≈66% of the VLBI detected sources in this field), with the excess radio flux measured from our SED analysis agreeing, to within a factor of two, with the radio core emission measured by VLBI. We find that the fraction of radio-excess AGN increases with X-ray luminosity reaching ∼60% at L X ≈ 10 44 −10 45 erg s −1 , making these sources an important part of the total AGN population. However, almost half (24/51) of these radio-excess AGN are not detected in the deep Chandra X-ray data, suggesting that some of these sources might be heavily obscured. Amongst the radio-excess AGN we can distinguish three groups of objects: i) AGN clearly identified in infrared (and often in X-rays), a fraction of which are likely to be distant Compton-thick AGN; ii) moderate luminosity AGN (L X 10 43 erg s −1 ) hosted in strong star-forming galaxies; and iii) a small fraction of low accretion-rate AGN hosted in passive (i.e. weak or no star-forming) galaxies. We also find that the specific star formation rates (sSFRs) of the radio-excess AGN are on average lower that those observed for X-ray selected AGN hosts, indicating that our sources are forming stars more slowly than typical AGN hosts, and possibly their star formation is progressively quenching.

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Section: "Passive" Systemsmentioning

confidence: 99%

GOODS-Herschel: radio-excess signature of hidden AGN activity in distant star-forming galaxies

Moro

Alexander

Mullaney

et al. 2012

A&A

130

112

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“…Note that the change from harder-when-brighter to softer-whenbrighter atṁcrit occurs within the hard state and is not considered to be a state transition. The accretion rate below which BHXRBs are never seen in the soft state ( 2% m Edd ; Maccarone et al (2003)) occurs factors of 2-3 abovė mcrit.…”

Section: Introductionmentioning

confidence: 99%

Long-term X-ray spectral variability in AGN from the Palomar sample observed bySwift

Connolly

McHardy

Skipper

et al. 2016

Mon. Not. R. Astron. Soc.

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We present X-ray spectral variability of 24 local active galactic nuclei (AGN) from the Palomar sample of nearby galaxies, as observed mainly by Swift. From hardness ratio measurements, we find that 18 AGN with low accretion rates show hardening with increasing count rate, converse to the softer-when-brighter behaviour normally observed in AGN with higher accretion rates. Two AGN show softening with increasing count rate, two show more complex behaviour, and two do not show any simple relationship.Sufficient data were available for the spectra of 13 AGN to be summed in fluxbins. In 9 of these sources, correlated luminosity-dependent changes in the photon index (Γ) of a power-law component are found to be the main cause of hardness variability. For 6 objects, with a low accretion rate as a fraction of the Eddington rate (ṁ Edd ), Γ is anticorrelated withṁ Edd , i.e. 'harder-when-brighter' behaviour is observed. The 3 higher-ṁ Edd -rate objects show a positive correlation between Γ anḋ m Edd . This transition from harder-when-brighter at lowṁ Edd to softer-when-brighter at highṁ Edd can be explained by a change in the dominant source of seed-photons for X-ray emission from cyclo-synchrotron emission from the Comptonising corona itself to thermal seed-photons from the accretion disc. This transition is also seen in the 'hard state' of black hole X-ray binaries (BHXRBs). The results support the idea that LINERs are analogues of BHXRBs in the hard state and that Seyferts are analogues of BHXRBs in either the high-accretion-rate end of the hard state or in the hard-intermediate state.

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“…Recent studies of the dependence of the radioloudness on the Eddington-ratio in AGNs and XRBs indicate that the jet-to-accretion power ratio increases with the decreasing accretion rate, and that at the high accretion rates the jet production is strongly suppressed in majority of objects (Ho, 2002;Gallo et al, 2003;Maccarone et al, 2003). In addition, the previous claims that powerful extragalactic radio sources avoid disk galaxies (Matthews et al, 1964;Xu et al, 1999) have been confirmed, and, as shown by SSL07, such a radio bimodality persists over an entire investigated range of the Eddingtonratios.…”

Section: Discussionmentioning

confidence: 99%

“…Around the same time, a trend for the increasing radio-loudness with the decreasing accretion luminosity was discovered also in the low/hard states of XRBs . Following these results, Maccarone et al (2003) constructed a 'fundamental plane' which attempts unifying the dependence of radio activity on accretion rate for all the BH (i.e., galactic and extragalactic) accretion systems.…”

Section: Radio-loudnessmentioning

confidence: 99%

Radio-loudness of active galaxies and the black hole evolution

Sikora

Stawarz

Lasota

2008

New Astronomy Reviews

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Active galactic nuclei (AGNs) form two distinct sequences on the radio-loudness -Eddington-ratio plane. The 'upper' sequence contains radio selected AGNs, the 'lower' sequence is composed mainly of optically selected AGNs. The sequences mark the upper bounds for the radio-loudness of two distinct populations of AGNs, hosted respectively by elliptical and disk galaxies. Both sequences show the same dependence of the radio-loudness on the Eddington ratio (an increase with decreasing Eddington ratio), which suggests that another parameter in addition to the accretion rate must play a role in determining the efficiency of jet production in AGNs. We speculate that this additional parameter is the spin of the black hole, assuming that black holes in giant elliptical galaxies have (on average) much larger spins than black holes in disc galaxies. Possible evolutionary scenarios leading to such a spin dichotomy are discussed. The galaxy-morphology related radio-dichotomy breaks down at high accretion rates where the dominant fraction of luminous quasars being hosted by giant ellipticals is radio quiet. This indicates that the production of powerful jets at high accretion rates is in most cases suppressed and, in analogy to X-ray binary systems (XRB) during high and very high states, may be intermittent. Such intermittency can be caused by switches between two different accretion modes, assuming that only during one of them an outflow from the central engine is sufficiently collimated to form a relativistic jet.

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The connection between radio-quiet active galactic nuclei and the high/soft state of X-ray binaries

Cited by 175 publications

References 66 publications

GOODS-Herschel: radio-excess signature of hidden AGN activity in distant star-forming galaxies

GOODS-Herschel: radio-excess signature of hidden AGN activity in distant star-forming galaxies

Long-term X-ray spectral variability in AGN from the Palomar sample observed bySwift

Radio-loudness of active galaxies and the black hole evolution

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