The X-ray to optical-UV luminosity ratio of X-ray selected type 1 AGN in XMM-COSMOS

By E. Lusso, A. Comastri, C. Vignali, G. Zamorani, M. Brusa, R. Gilli, K. Iwasawa, Mara Salvato, F. Civano, M. Elvis and 22 more. 2009

302 citations recorded by the source corpus.

We present a study of the X-ray to optical properties of a sample of 545 X-ray selected type 1 AGN, from the XMM-COSMOS survey, over a wide range of redshifts (0.04 \textless z \textless 4.25) and X-ray luminosities (40.6 \textless= Log L([2-10]) (keV) \textless= 45.3). About 60% of them are spectroscopically identified type 1 AGN, while the others have a reliable photometric redshift and are classified as type 1 AGN on the basis of their multi-band Spectral Energy Distributions. We discuss the relationship between UV and X-ray luminosity, as parameterized by the alpha(ox) spectral slope, and its dependence on redshift and luminosity. We compare our findings with previous investigations of optically selected broad-line AGN (mostly from SDSS). A highly significant correlation between alpha(ox) and L(2500) angstrom is found, in agreement with previous investigations of optically selected samples. We calculate bolometric corrections, k(bol), for the whole sample using hard X-ray luminosities (L([2-10] keV)), and the Eddington ratios for a subsample of 150 objects for which black hole mass estimates are available. We confirm the trend of increasing bolometric correction with increasing Eddington ratio as proposed in previous works. A tight correlation is found between alpha(ox) and k(bol), which can be used to estimate accurate bolometric corrections using only optical and X-ray data. We find a significant correlation between alpha(ox) and Eddington ratio, in which the ratio between X-ray and optical flux decreases with increasing Eddington ratio.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/cb7fe9d87a19705c776db03c10f58e6aa8b76f38

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Citations in the corpus

PRIMUS: THE DEPENDENCE OF AGN ACCRETION ON HOST STELLAR MASS AND COLOR (2011, background): “…of recent studies, however, have used observed multiband SEDs of unobscured AGNs to accurately measure bolometric luminosities and propose that k2−10keV may be more closely correlated with the Eddington ratio, albeit with significant scatter (Vasudevan & Fabian 2007, 2009; Lusso et al. 2010).”
Accreting supermassive black holes in the COSMOS field and the connection to their host galaxies (2012, background): “As we have anticipated, to the first order, the data are consistent with a power-law-like distribution and a clear break at values of 9 Recently, Lusso et al. (2010, 2011) have shown that the 2–10 keV bolometric correction is likely to be an increasing function of the Eddington ratio itself; this is”
Universal bolometric corrections for active galactic nuclei over seven luminosity decades (2020, background): “Some authors have investigated the evolution of the αOX spectral index (see, e.g., Kelly et al. 2008; Vasudevan et al. 2009; Lusso et al. 2010; Marchese et al. 2012; Lusso & Risaliti 2017), which should provide an indication about the nature of the energy generation mechanism in AGN.”
Enhanced star formation rates in AGN hosts with respect to inactive galaxies from PEP-Herschel observations (2012, methodology): “Following Lusso et al. (2010), we considered Type 1 all the objects best-fitted by a QSO or hybrid Type 1 - galaxy template (model SED≥ 18 in Salvato et al. 2009), and Type 2 all the remaining objects.”
Modeling the Radio Background from the First Black Holes at Cosmic Dawn: Implications for the 21 cm Absorption Amplitude (2018, methodology): “L k f L2 10 bol 1 edd E between 2 and 10 keV, where we use a bolometric correction factor of =-k 0.07bol 1 , consistent with the distribution observed by Lusso et al. (2010).”
Erratum: Updating quasar bolometric luminosity corrections (2012, methodology): “This dependence has specifically been characterized, most recently by Marchese et al. (2011) for 195 X-ray selected Type 1 AGN from the XMM-Newton serendipitous survey and also Lusso et al. (2010) for 545 Type 1 AGN from the XMM-COSMOS survey.”
THE SIMULTANEOUS OPTICAL-TO-X-RAY SPECTRAL ENERGY DISTRIBUTION OF SOFT X-RAY SELECTED ACTIVE GALACTIC NUCLEI OBSERVED BY SWIFT (2010, background): “Note that the scatter in our relation is significantly smaller than in the Lusso et al. (2010) sample.”
Evolution of the AGN UV luminosity function from redshift 7.5 (2018, background): “…samples are less suited for this purpose due to spectroscopic incompleteness and the ∼ 0.4 dex scatter in the conversion from X-ray to UV luminosity (Lusso et al. 2010; Georgakakis et al. 2015; Lusso & Risaliti 2016) that contributes significantly to the error budget in the UV luminosity function…”
Unification of X-ray winds in Seyfert galaxies: from ultra-fast outflows to warm absorbers (2012, methodology): “The bolometric luminosity Lbol is estimated as Lbol = kbolLion, where kbol≃10 (McKernan et al. 2007; Vasudevan & Fabian 2009; Lusso et al. 2010).”
Accretion-driven evolution of black holes: Eddington ratios, duty cycles and active galaxy fractions (2011, background): “22 as a reference, noting that the Lusso et al. (2010) fits provide consistent results in the range of interest here.”
A HUBBLE DIAGRAM FOR QUASARS (2015, methodology): “…20 1.760–4.610 32.14–32.85 27.14–28.07 Just et al. (2007) 14 4.720–6.220 31.38–32.42 26.62–27.62 Shemmer et al. (2006) 327 0.345–4.255 28.96–31.79 25.08–27.14 Lusso et al. (2010) 225 0.173–4.441 29.33–32.40 25.08–27.78 Young et al. (2010) 808 0.061–6.280 28.94–32.90 25.08–28.09 Total Figure…”
IDENTIFYING LUMINOUS ACTIVE GALACTIC NUCLEI IN DEEP SURVEYS: REVISED IRAC SELECTION CRITERIA (2012, background): “…they are far more highly sampled in the UV/optical than in the MIR, and they do not reflect the intrinsic variation seen in any given class of AGN (for more detailed SED analyses, see Salvato et al. (2009), Hao et al. (2010), Lusso et al. (2010), Trump et al. (2011a), Lusso et al. (2011, in prep.)”
The Illustris simulation: the evolving population of black holes across cosmic time (2014, methodology): “Current observations probe a too narrow dynamic range in X-ray luminosities to see this correlation, even though it can be inferred if the spectroscopically confirmed COSMOS data (Lusso et al. 2010, 2011; Brusa et al. 2010; Bongiorno et al. 2012) at all redshifts are combined together.”
The bolometric quasar luminosity function at z = 0–7 (2020, background): “These investigations of the QLF have also found that both the typical spectral shape (e.g., Wilkes et al. 1994; Green et al. 1995; Vignali et al. 2003; Strateva et al. 2005; Richards et al. 2006b; Steffen et al. 2006; Just et al. 2007; Lusso et al. 2010; Kashikawa et al. 2015; Lusso & Risaliti 2016)”
Bolometric luminosities and Eddington ratios of X-ray selected active galactic nuclei in the XMM-COSMOS survey (2012, background): “…and the optical luminosity (Tananbaum et al. 1979; Zamorani et al. 1981; Vignali et al. 2003; Steffen et al. 2006; Just et al. 2007; Young et al. 2009; Lusso et al. 2010; Marchese et al. 2012), or betweenαox and the Eddington ratio (Vasudevan & Fabian 2007; Kelly et al. 2008; Vasudevan etal.”
A statistical relation between the X-ray spectral index and Eddington ratio of active galactic nuclei in deep surveys (2013, methodology): “Lusso et al. (2010) showed that this can be done reliably using κ2−10 derived from the X-ray to optical spectral index, αOX. αOX is normally calculated using the monochromatic luminosities at 2500 Å and 2 keV; however, we utilize the 3000 Å luminosity we already have at hand from the line…”
The incidence of obscuration in active galactic nuclei (2013, background): “These values of extinction are consistent with the findings of Lusso et al. (2010), who have studied in detail the SED of spectroscopic type-1 AGN in COSMOS, concluding that only a negligible minority appears to suffer from reddening in excess of E(B − V) = 0.2.”
THE BULK OF THE BLACK HOLE GROWTH SINCE z ∼ 1 OCCURS IN A SECULAR UNIVERSE: NO MAJOR MERGER–AGN CONNECTION (2010, methodology): “The values were obtained mainly from those calculated by Lusso et al. (2010) and are complemented with those by Mainieri et al. (2007).”