Chandra and XMM-Newton Observations of a Sample of Low-Redshift FR I and FR II Radio Galaxy Nuclei

By D. Evans, D. Worrall, M. Hardcastle, R. Kraft, M. B. U. O. Bristol, H. C. F. Astrophysics, U. Hertfordshire. 2005

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We present spectral results from Chandra and XMM-Newton observations of a sample of 22 low-redshift (z < 0.1) radio galaxies and consider whether the core emission originates from the base of a relativistic jet, or an accretion flow, or contains contributions from both. We find correlations between the unabsorbed X-ray, radio, and optical fluxes and luminosities of FR I-type radio-galaxy cores, implying a common origin in the form of a jet. On the other hand, we find that the X-ray spectra of FR II-type radio galaxy cores are dominated by absorbed emission, with NH ≳ 1023 atoms cm-2, which is likely to originate in an accretion flow. We discuss several models that may account for the different nuclear properties of FR I- and FR II-type cores and also demonstrate that both heavily obscured, accretion-related and unobscured, jet-related components may be present in all radio galaxy nuclei. Any absorbed, accretion-related components in FR I-type galaxies have low radiative efficiencies.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/f19144d784cb25c2c0183d41d20b1c707c8f9e71

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Citations in the corpus

The VLA-COSMOS 3 GHz Large Project: Continuum data and source catalog release (2017, background): “…nuclei (AGN) that are hosted by the most massive quiescent galaxies and deemed crucial for massive galaxy formation (e.g., Croton et al. 2006; Bower et al. 2006; Best et al. 2006; Evans et al. 2006; Hardcastle et al. 2007; Smolčić et al. 2009a, 2015; Smolčić 2009; Smolčić & Riechers 2011).”
Nuclear Activity in Nearby Galaxies (2008, background): “…et al. 1999; Chiaberge, Capetti & Celotti 1999, 2000; Capetti et al. 2002; Verdoes Kleijn et al. 2002; Donato, Sambruna & Gliozzi 2004; Balmaverde & Capetti 2006; Balmaverde, Capetti & Grandi 2006; Evans et al. 2006; for a counterargument, see Rinn, Sambruna & Gliozzi 2005 and Gliozzi et al. 2008).”
Hot and cold gas accretion and feedback in radio-loud active galaxies (2007, background): “Most recently, we have argued (Evans et al. 2006; Hardcastleet al. 2006, hereafter H06) that both low-power FRI and high-powerFRII LERGs show no evidence for accretion-related X-ray emission, absorbed or unabsorbed, over and above what is likely to originate in the nuclear (pc-scale) jets.”
Swift BAT Survey of AGNs (2007, unknown): “(1) Swift XRT; (2) XTE/Akylas et al. 2002; (3) XMM/L. M. Winter et al. 2008a, in preparation; (4) Lutz et al. 2004; (5) Sambruna et al. 1998; (6) ASCA/R. F. Mushotzky et al. 2008, in preparation; (7) Gallo et al. 2006; (8) Tartarus database; (9) XMM/R. F. Mushotzky et al. 2008, in preparation; (10) ”
A simplified view of blazars: clearing the fog around long‐standing selection effects (2011, background): “Evans et al. (2006) have shown that the accretion flow luminosities of FR IIs are typically several orders of magnitude higher than those of FR Is.”
Accretion states and radio loudness in active galactic nuclei: analogies with X-ray binaries (2006, background): “On the other hand, Evans et al. (2006) found a contribution to the X-ray emission of high-power radio galaxies and quasars from both the accretion flow (i.e. the disc) and the jet, indicating that the X-ray emission is not purely due to a beamed component.”
Using the Fundamental Plane of black hole activity to distinguish X-ray processes from weakly accreting black holes (2011, background): “They have subEddington accretion rates, and, especially as ṁ decreases, their broad-band SEDs (including X-ray emission) are generally jetdominated (e.g. Evans et al. 2006).”
What drives the growth of black holes (2011, background): “…Seyfert and quasar classifications) are typically hosted in less massive gas-rich galaxies (e.g., Willott et al., 2001; Chiaberge et al., 2005; Evans et al., 2006; Hardcastle et al., 2006, 2007; Baldi & Capetti, 2008; Kauffmann et al., 2008; Smolčić, 2009; Smolčić et al., 2009; Herbert et…”
Radiative efficiency, variability and Bondi accretion on to massive black holes: the transition from radio AGN to quasars in brightest cluster galaxies (2012, unknown): “4 (see also Evans et al. 2006).”
Measuring the kinetic power of active galactic nuclei in the radio mode (2007, methodology): “This result is not substantially modified if we allow at least a non negligible fraction of the X-ray core luminosity to originate in the jet, as recently argued on the basis of either X-ray spectroscopy alone (Evans et al. 2006) or on model fitting of multiwavelength SED (Wu, Yuan & Cao 2007).”
First X-ray-based statistical tests for clumpy-torus models: eclipse events from 230 years of monitoring of Seyfert AGN (2014, unknown): “References for typical values of Γ and NH are: B11 = Brightman & Nandra (2011); E06 = Evans et al. (2006); G09 = González-Mart́ın et al. (2009); R11 = Rivers et al. (2011a); R13 = Rivers et al. (2013); R02 = Risaliti, Elvis & Nicastro (2002) and references therein; TW = this work (Mkn 348: average…”
The X-ray nuclei of intermediate-redshift radio sources (2006, background): “Lowredshift (z < 0.1) 3C and 3CRR sources, largely FRIs, have been studied by several groups (Donato et al. 2004; Evans et al. 2006 (hereafter E06); Balmaverde et al. 2006): all find that essentially all sources show a soft component of nuclear emission whose luminosity correlates with that of the…”
The active nuclei of z < 1.0 3CRR radio sources (2009, methodology): “…the case where line emission arises on scales comparable to that of the NLR, as is known in some Seyferts even in the presence of radio jets (e.g. Evans et al. 2006b); grating spectroscopy shows that the soft X-rays can be completely dominated by emission lines from material photoionized by the…”
X-RAY SPECTRAL PROPERTIES OF THE BAT AGN SAMPLE (2008, background): “3C 452: 3C 452 has an extremely flat spectrum which is much better fit with the addition of a reflection model (Evans et al. 2006).”