Compact radio emission from<i>z</i> ~  0.2 X-ray bright AGN

Zuther, J.; Fischer, Sebastian; Eckart, A.

doi:10.1051/0004-6361/201118200

Cited by 9 publications

(8 citation statements)

References 102 publications

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“…The 2-10 keV Xray luminosities and X-ray photon indices are selected from Zhou & Zhang (2010), which are derived from targeted observations from XMM-Newton. The radio emission from these RQ AGNs mainly originate from compact nuclear region and the contribution from star formation in the host galaxies normally can be neglected (e.g., Zuther et al 2012). In total, we have 64 bright RQ AGNs (see Table 1 for more details).…”

Section: Samplementioning

confidence: 99%

A New Fundamental Plane for Radiatively Efficient Black-Hole Sources

Dong

Wu²,

Cao

2014

ApJ

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In recent years, it was found that there are several low/hard state of X-ray binaries (XRBs) follow an 'outliers' track of radio-X-ray correlation (L R ∝ L b X and b ∼ 1.4), which is much steeper than the former universal track with b ∼ 0.6. In this work, we compile a sample of bright radio-quiet active galactic nuclei (AGNs) and find that their hard X-ray photon indices and Eddington ratios are positively correlated, which is similar to that of 'outliers' of XRBs, where both bright AGNs and 'outliers' of XRBs have bolometric Eddington ratios 1%L Edd (L Edd is Eddington luminosity). The Eddington-scaled radio-X-ray correlation of these AGNs is also similar to that of 'outliers' of XRBs, which has a form of L 5GHz /L Edd ∝ (L 2−10keV /L Edd ) c with c ≃ 1.59 and 1.53 for AGNs and XRBs respectively. Both the positively correlated X-ray spectral evolution and the steeper radio-X-ray correlation can be regulated by a radiatively efficient accretion flow (e.g., disk-corona). Based on these similarities, we further present a new fundamental plane for 'outliers' of XRBs and bright AGNs in black-hole (BH) mass, radio and X-ray luminosity space: log L R = 1.59 +0.28 −0.22 log L X − 0.22 +0.19 −0.20 log M BH − 28.97 +0.45 −0.45 with a scatter of σ R = 0.51dex. This fundamental plane is suitable for radiatively efficient BH sources, while the former plane proposed by Merloni et al. and Falcke et al. may be most suitable for radiatively inefficient sources.

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Section: Samplementioning

confidence: 99%

A New Fundamental Plane for Radiatively Efficient Black-Hole Sources

Dong

Wu²,

Cao

2014

ApJ

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“…In Radio Loud (RL) AGN the radio emission is often spatially resolved with a jet like structure, which on milli-arcsec (hereafter mas) scales often shows super luminal motion indicative of bulk relativistic motion. In radio quiet AGN (Kellermann et al 1989;Miller et al 1993), a significant fraction of the radio emission is often unresolved (Kellermann et al 1994;Kukula et al 1998;Leipski et al 2006;Zuther et al 2012), even on pc scale (Blundell & Beasley 1998;Caccianiga et al 2001;Ulvestad et. al 2005a;Doi et al 2013;Panessa & Giroletti 2013).…”

Section: Introductionmentioning

confidence: 99%

AGN coronal emission models – I. The predicted radio emission

Raginski¹,

Laor²

2016

Mon. Not. R. Astron. Soc.

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Accretion discs in AGN may be associated with coronal gas, as suggested by their X-ray emission. Stellar coronal emission includes radio emission, and AGN corona may also be a significant source for radio emission in radio quiet (RQ) AGN. We calculate the coronal properties required to produce the observed radio emission in RQ AGN, either from synchrotron emission of power-law (PL) electrons, or from cyclo-synchrotron emission of hot mildly-relativistic thermal electrons. We find that a flat spectrum, as observed in about half of RQ AGN, can be produced by corona with a disc or a spherical configuration, which extends from the innermost regions out to a pc scale. A spectral break to an optically thin power-law emission is expected around 300-1000 GHz, as the innermost corona becomes optically thin. In case of thermal electrons, a sharp spectral cutoff is expected above the break. The position of the break can be measured with VLBI observations, which exclude the cold dust emission, and it can be used to probe the properties of the innermost corona. Assuming equipartition of the coronal thermal energy density, the PL electrons energy density, and the magnetic field, we find that the energy density in a disc corona should scale as ∼ R −1.3 , to get a flat spectrum. In the spherical case the energy density scales as ∼ R −2 , and is ∼ 4 × 10 −4 of the AGN radiation energy density. In paper II we derive additional constraints on the coronal parameters from the Gudel-Benz relation, L radio /L X−ray ∼ 10 −5 , which RQ AGN follow.

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“…Figure 1 presents the image of the radio source. Details of the radio observation and data reduction are given in Zuther et al (2012). An extended structure at the central source component of J0808 gives some evidence for a possible backflow towards the center that may result in an interaction with the ISM at the nucleus.…”

Section: Merlin 18 CM Observationmentioning

confidence: 99%

High-resolution observations of SDSS J080800.99+483807.7 in the optical and radio domains

Rashed

Zuther

Eckart

et al. 2013

A&A

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Context. Double-lobe radio galaxies are ideally suited to investigate the interaction of the individual components of the radio structure with the intergalactic medium and the interstellar medium of the host galaxy. SDSS J080800.99+483807.7 has been serendipitously discovered in MERLIN 18 cm observations to be a double-lobed radio galaxy. Because it is an optically faint source, basic information like redshift, linear size, and structure has been incomplete until now. Furthermore, there are no spectra of this source available in any databases. Aims. The goal of this work is to derive the main physical properties of SDSS J080800.99+483807.7 and study the possible interaction between the radio jets and the interstellar medium of the host galaxy. Methods. To achieve this goal, we used optical spectroscopy and radio interferometry. The radio data were obtained with MERLIN at 18 cm and the optical data with the Multi-Object Double Spectrograph (MODS) at the Large Binocular Telescope (LBT).Results. The redshift of the galaxy is z = 0.2805 ± 0.0003, resulting in a linear size of the observed radio structure of ∼26.3 kpc. The optical line emission as well as the infrared and radio continuum emission suggest a high star-formation activity. In addition, we estimated the mass of the central black hole to be log (M BH /M ) ≈ 6.9. Conclusions. The MODS spectrum and the optical images from Sloan Digital Sky Survey suggest that SDSS J080800.99+483807.7 is an elliptical host galaxy. In combination with the overall radio structure, we argue that the star formation could be the result of the back-flow along the jet and the interstellar medium of the host.

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Compact radio emission fromz ~ 0.2 X-ray bright AGN

Cited by 9 publications

References 102 publications

A New Fundamental Plane for Radiatively Efficient Black-Hole Sources

A New Fundamental Plane for Radiatively Efficient Black-Hole Sources

AGN coronal emission models – I. The predicted radio emission

High-resolution observations of SDSS J080800.99+483807.7 in the optical and radio domains

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