The Far‐Infrared Spectral Energy Distributions of X‐Ray–selected Active Galaxies

Kuraszkiewicz, Joanna; Wilkes, B. J.; Hooper, E. J.; McLeod, Kim K.; Wood, Kenneth; Bjorkman, J. E.; Delain, K. M.; Hughes, D. H.; Elvis, M.; Impey, C. D.; Lonsdale, C. J.; Malkan, M.; McDowell, Jonathan; Whitney, B. A.

doi:10.1086/374919

Cited by 70 publications

(107 citation statements)

References 94 publications

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“…The ratios of the rest-frame UV/optical luminosities to the rest-frame 2-8 keV luminosities match those of the local hard X-ray broadline AGN sample analyzed by Kuraszkiewicz et al (2003).…”

Section: Composite Spectral Energy Distributions By Spectral Typesupporting

confidence: 60%

“…In Figure 36, we show the mean bolometric luminosities (relative to the X-ray luminosities) versus the rest-frame frequencies for the (a) broad-line AGNs and (b) optically narrow AGNs. The dashed curve that appears in both plots shows the median value for the local hard X-ray-selected sample of Kuraszkiewicz et al (2003), which is primarily broad-line AGNs with a small admixture of intermediate-type Seyferts.…”

Section: Composite Spectral Energy Distributions By Spectral Typementioning

confidence: 99%

“…The small squares show the individual measurements for the mid-infrared, optical, UV, and soft X-ray samples. The dashed curves show the median value for the local hard X-ray-selected sample of Kuraszkiewicz et al (2003), which is primarily broad-line AGNs with a small admixture of intermediate-type Seyferts. In (b), the dot-dashed curve denotes the spectral energy distribution of the optically thick local galaxy NGC 6240 from Hasinger (2000), normalized to give a bolometric correction of 35.…”

Section: Composite Spectral Energy Distributions By Hard X-ray Luminomentioning

confidence: 99%

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The Cosmic Evolution of Hard X-Ray-selected Active Galactic Nuclei

et al. 2005

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We use highly spectroscopically complete deep and wide-area Chandra surveys to determine the cosmic evolution of hard X-ray-selected active galactic nuclei (AGNs). For the deep fields, we supplement the spectroscopic redshifts with photometric redshifts to assess where the unidentified sources are likely to lie. We find that the median redshifts are fairly constant with X-ray flux at z $ 1.We classify the optical spectra and measure the FWHM line widths. Most of the broad-line AGNs show essentially no visible absorption in X-rays, whereas the sources without broad lines (FWHM < 2000 km s À1 ; ''optically narrow'' AGNs) show a wide range of absorbing column densities. We determine hard X-ray luminosity functions for all spectral types with L X ! 10 42 ergs s À1 and for broad-line AGNs alone. At z < 1:2, both are well described by pure luminosity evolution, with L * evolving as (1 þ z) 3:2AE0:8 for all spectral types and as (1 þ z) 3:0AE1:0 for broad-line AGNs alone. Thus, all AGNs drop in luminosity by almost an order of magnitude over this redshift range. We show that this observed drop is due to AGN downsizing rather than to an evolution in the accretion rates onto the supermassive black holes.We directly compare our broad-line AGN hard X-ray luminosity functions with the optical QSO luminosity functions and find that at the bright end they agree extremely well at all redshifts. However, the optical QSO luminosity functions do not probe faint enough to see the downturn in the broad-line AGN hard X-ray luminosity functions and even appear to be missing some sources at the lowest luminosities they probe.We find that broad-line AGNs dominate the number densities at the higher X-ray luminosities, while optically narrow AGNs dominate at the lower X-ray luminosities. We rule out galaxy dilution as a partial explanation for this effect by measuring the nuclear UV/optical properties of the Chandra sources using the Hubble Space Telescope Advanced Camera for Surveys GOODS-North data. The UV/optical nuclei of the optically narrow AGNs are much weaker than expected if the optically narrow AGNs were similar to the broad-line AGNs. We therefore postulate the need for a luminosity-dependent unified model. An alternative possibility is that the broad-line AGNs and the optically narrow AGNs are intrinsically different source populations. We cover both interpretations by constructing composite spectral energy distributions-including long-wavelength data from the mid-infrared to the submillimeterby spectral type and by X-ray luminosity. We use these spectral energy distributions to infer the bolometric corrections (from hard X-ray luminosities to bolometric luminosities) needed to map the accretion history.We determine the accreted supermassive black hole mass density for all spectral types and for broad-line AGNs alone, using the observed evolution of the hard X-ray energy density production rate and our inferred bolometric corrections. We find that only about one-half to one-quarter of the supermassive black hole mass ...

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Section: Composite Spectral Energy Distributions By Spectral Typesupporting

confidence: 60%

Section: Composite Spectral Energy Distributions By Spectral Typementioning

confidence: 99%

Section: Composite Spectral Energy Distributions By Hard X-ray Luminomentioning

confidence: 99%

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The Cosmic Evolution of Hard X-Ray-selected Active Galactic Nuclei

et al. 2005

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“…There exists broad agreement that the AGN-heated nuclear dust is mainly located in clumps which are distributed in a toroidal pattern altogether referred to as the AGN torus (e.g. Nenkova et al 2002;Kuraszkiewicz et al 2003;Hönig et al 2006;Schartmann et al 2008). To account for the emission from the AGN heated dust, we chose the library of torus models from Hönig & Kishimoto (2010).…”

Section: Fitting Componentsmentioning

confidence: 99%

Star formation inz> 1 3CR host galaxies as seen byHerschel

Podigachoski

Barthel

Haas

et al. 2015

A&A

122

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We present Herschel (PACS and SPIRE) far-infrared (FIR) photometry of a complete sample of z > 1 3CR sources, from the Herschel guaranteed time project The Herschel Legacy of distant radio-loud AGN. Combining these with existing Spitzer photometric data, we perform an infrared (IR) spectral energy distribution (SED) analysis of these landmark objects in extragalactic research to study the star formation in the hosts of some of the brightest active galactic nuclei (AGN) known at any epoch. Accounting for the contribution from an AGN-powered warm dust component to the IR SED, about 40% of our objects undergo episodes of prodigious, ULIRGstrength star formation, with rates of hundreds of solar masses per year, coeval with the growth of the central supermassive black hole. Median SEDs imply that the quasar and radio galaxy hosts have similar FIR properties, in agreement with the orientationbased unification for radio-loud AGN. The star-forming properties of the AGN hosts are similar to those of the general population of equally massive non-AGN galaxies at comparable redshifts, thus there is no strong evidence of universal quenching of star formation (negative feedback) within this sample. Massive galaxies at high redshift may be forming stars prodigiously, regardless of whether their supermassive black holes are accreting or not.

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“…Kuraszkiewicz et al (2003) considered a sample of X-ray-selected luminous AGN (10 43 < L 2−10 keV < 10 46 erg s −1 ) and find a median k 2−10 keV of 18. Ballo et al (2007), analysed a sample of low-luminosity AGN (10 42 < L 2−10 keV < 10 43.6 erg s −1 ) and find a median k 2−10 keV of 12.…”

Section: Hard X-ray Bolometric Correctionsmentioning

confidence: 99%

The HELLAS2XMM survey

Pozzi

Vignali

Comastri

et al. 2010

A&A

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Aims. We combine near-to-mid-IR Spitzer data with shorter wavelength observations (optical to X-rays) to get insight into the properties of a sample of luminous, obscured active galactic nuclei (AGN). We aim at modelling their broad-band spectral energy distributions (SEDs) in order to estimate the main parameters related to the dusty torus that is assumed to be responsible for the reprocessed IR emission. Our final goal is to estimate the intrinsic nuclear luminosities and the Eddington ratios for our luminous, obscured AGN. Methods. The sample comprises 16 obscured high-redshift (0.9 < ∼ z < ∼ 2.1), X-ray luminous quasars (L 2−10 keV ∼ 10 44 erg s −1 ) selected from the HELLAS2XMM survey in the 2-10 keV band. The optical-IR SEDs are described by a multi-component model that includes a stellar component to account for the optical and near-IR emission, an AGN component that dominates in the mid-IR (mainly emission from a dusty torus heated by nuclear radiation), and a starburst to reproduce the far-IR bump. A radiative transfer code to compute the spectrum and intensity of dust reprocessed emission was extensively tested against our multiwavelength data. While the torus parameters and the BH accretion luminosities are a direct output of the SED-fitting procedure, the BH masses were estimated indirectly by means of the local M bulge -M BH relation. Results. The majority (∼80%) of the sources show moderate optical depth (τ 9.7 μm ≤ 3), and the derived column densities N H are consistent with the X-ray inferred values (10 22 < ∼ N H < ∼ 3 × 10 23 cm −2 ) for most of the objects, confirming that the sources are moderately obscured Compton-thin AGN. Accretion luminosities in the range 5 × 10 44 < ∼ L bol < ∼ 4 × 10 46 erg s −1 are inferred from the multiwavelength fitting procedure. We compare model luminosities with those obtained by integrating the observed SED, finding that the latter are lower by a factor of ∼2 in the median. The discrepancy can be as high as an order of magnitude for models with high optical depth (τ 9.7 μm = 10). The ratio between the luminosities obtained by the fitting procedure and from the observed SED suggest that, at least for type 2 AGN, observed bolometric luminosities are likely to underestimate intrinsic ones and the effect is more severe for highly obscured sources. Bolometric corrections from the hard X-ray band are computed and have a median value of k 2−10 keV ∼ 20. The obscured AGN in our sample are characterized by relatively low Eddington ratios (median λ Edd ∼ 0.08). On average, they are consistent with the Eddington ratio increasing at increasing bolometric correction.

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The Far‐Infrared Spectral Energy Distributions of X‐Ray–selected Active Galaxies

Cited by 70 publications

References 94 publications

The Cosmic Evolution of Hard X-Ray-selected Active Galactic Nuclei

The Cosmic Evolution of Hard X-Ray-selected Active Galactic Nuclei

Star formation inz> 1 3CR host galaxies as seen byHerschel

The HELLAS2XMM survey

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