Spectral Energy Distributions and Multiwavelength Selection of Type 1 Quasars

By G. T. Richards, M. Lacy, L. Storrie-Lombardi, P. Hall, S. C. Gallagher, D. Hines, Xiaohui Fan, C. Papovich, D. V. vanden Berk, G. B. Trammell and 7 more. 2006

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We present an analysis of the mid-infrared (MIR) and optical properties of type 1 (broad-line) quasars detected by the Spitzer Space Telescope. The MIR color-redshift relation is characterized to z ~ 3, with predictions to z = 7. We demonstrate how combining MIR and optical colors can yield even more efficient selection of active galactic nuclei (AGNs) than MIR or optical colors alone. Composite spectral energy distributions (SEDs) are constructed for 259 quasars with both Sloan Digital Sky Survey and Spitzer photometry, supplemented by near-IR, GALEX, VLA, and ROSAT data, where available. We discuss how the spectral diversity of quasars influences the determination of bolometric luminosities and accretion rates; assuming the mean SED can lead to errors as large as 50% for individual quasars when inferring a bolometric luminosity from an optical luminosity. Finally, we show that careful consideration of the shape of the mean quasar SED and its redshift dependence leads to a lower estimate of the fraction of reddened/obscured AGNs missed by optical surveys as compared to estimates derived from a single mean MIR to optical flux ratio.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/cba5322e64e42b98e0b5a8fedb1a8a756a947a19

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Citations in the corpus

SPECTROSCOPY OF BROAD-LINE BLAZARS FROM 1LAC (2012, methodology): “We first use the line fluxes to estimate local continuum luminosities, as above, then convert these to bolometric fluxes using factors from Richards et al. (2006) (Lbol/L5100 = 9.26, Lbol/L3000 = 5.15, Lbol/L1350 = 3.81).”
Discovery of extreme [O III] λ5007 Å outflows in high-redshift red quasars (2015, background): “They hinge on the shape of the SED in the far-infrared where in principle it could be contaminated by the star formation in the host galaxy, but Tsai et al. (2015) argue that it is not a significant fraction of the bolometric luminosity of the HotDOG template on the basis of molecular gas observatio”
Black Hole Growth to z = 2 - I: Improved Virial Methods for Measuring M_BH and L/L_Edd (2012, methodology): “As explained in §6.4, this transition wouldn’t appear as smooth if these quantities were obtained using the methods of McLure & Dunlop (2004) and Richards et al. (2006a).”
A CATALOG OF QUASAR PROPERTIES FROM SLOAN DIGITAL SKY SURVEY DATA RELEASE 7 (2010, methodology): “Some authors suggest to remove the IR bump in the SED in estimating the bolometric corrections (e.g., Marconi et al. 2004), where the IR radiation is assumed to come from the reprocessed UV radiation.”
LOW-RESOLUTION SPECTRAL TEMPLATES FOR ACTIVE GALACTIC NUCLEI AND GALAXIES FROM 0.03 TO 30 μm (2010, methodology): “We choose to make our initial template as blue in the optical as our bluest AGNs, which is significantly bluer than the Richards et al. (2006) SED.”
Faint high-redshift AGN in the Chandra deep field south: the evolution of the AGN luminosity function and black hole demography (2011, methodology): “…to the Chandra-COSMOS high-z sample of Civano et al. (2011), the XMM-COSMOS sample of Brusa et al. (2009a), the GOODS sample of Fontanot et al. (2007), the faint optical AGN sample of Glikman et al. (2011), and the luminous optical AGN samples of Richards et al. (2006) and Jiang et al. (2009).”
A HUBBLE DIAGRAM FOR QUASARS (2015, methodology): “We corrected our sample as explained in Section 3, assuming an intrinsic quasar SED as in Richards et al. (2006) and a standard extinction law.”
Black Hole Masses and Enrichment of z ~ 6 SDSS Quasars (2007, methodology): “…implies that the quasars are likely not strongly lensed, consistent with Black hole masses and enrichment of z ∼ 6 SDSS quasars 11 the conclusions derived from an analysis of HST images of these objects, none of the QSOs showing evidence for lensed counterparts (Richards et al. 2004, 2006a).”
A JWST/NIRSpec First Census of Broad-line AGNs at z = 4–7: Detection of 10 Faint AGNs with M BH ∼ 106–108 M ⊙ and Their Host Galaxy Properties (2023, background): “…the following equation between the luminosity at the rest-JWST frame 5100 ˚A, L 5100 , and the H α luminosity including both the broad and narrow components (Greene & Ho 2005): (17) and the relation between L 5100 and L bol with the bolo-metric correction in Richards et al. (2006), L bol = 10 .”
THE DISCOVERY OF THE FIRST “CHANGING LOOK” QUASAR: NEW INSIGHTS INTO THE PHYSICS AND PHENOMENOLOGY OF ACTIVE GALACTIC NUCLEI (2014, methodology): “We estimate the bolometric AGN luminosity (Lbol) to be 8.8×10 44 erg s−1, using λL5100 (see Richards et al. 2006, for a discussion of the reliability of various bolometric luminosities) and a conversion factor of 8.1 to convert from monochromatic to bolometric luminosity (Runnoe et al. 2012).”
Accretion-driven evolution of black holes: Eddington ratios, duty cycles and active galaxy fractions (2011, background): “The accretion onto the very massive black holes with log MBH/M⊙ > 8 always peaks at z ∼ 2, concurrent with the peak in the emissivity of luminous optical quasars (e.g., Osmer 1982; Richards et al. 2006; Croom et al. 2009).”
Observations of feedback from radio-quiet quasars – II. Kinematics of ionized gas nebulae (2013, methodology): “The simplest approach is to apply the standard photometric corrections derived from unobscured quasars (e.g. a factor of 9 at 12 μm; Richards et al. 2006).”
Tracing the cosmic growth of supermassive black holes to z ∼ 3 with Herschel (2014, background): “H07 adopted a distribution of luminosity dependent bolometric corrections for each selection wave band, as well as a large baseline of intrinsic (i.e. corrected for obscuration) AGN SED shapes (from Richards et al. 2006; Steffen et al. 2006).”
Galaxy pairs in the Sloan Digital Sky Survey – IX. Merger-induced AGN activity as traced by the Wide-field Infrared Survey Explorer (2014, methodology): “In galaxies dominated by an AGN, the W2 luminosity is well-correlated with the AGN bolometric luminosity (Richards et al. 2006).”
THE RADIATIVE EFFICIENCY OF ACCRETION FLOWS IN INDIVIDUAL ACTIVE GALACTIC NUCLEI (2010, background): “We note that a relatively uniform ratio of Lopt/Lbol has been found by previous authors (e.g. Elvis et al. 1994; Richards et al. 2006), and is, in fact, frequently assumed in the literature to estimate Lbol when only optical constraints are available.”
Defining the intrinsic AGN infrared spectral energy distribution and measuring its contribution to the infrared output of composite galaxies (2011, background): “There have been a number of attempts to constrain the average quasar SED, although only a handful have included coverage to FIR wavelengths (e.g. Elvis et al. 1994; Richards et al. 2006; Netzer et al. 2007).”
THE NEXT GENERATION ATLAS OF QUASAR SPECTRAL ENERGY DISTRIBUTIONS FROM RADIO TO X-RAYS (2011, background): “Richards et al. (2006) is the largest that covers the entire electromagnetic spectrum, including data from the Sloan Digital Sky Survey and Spitzer, supplemented by near-IR, GALEX ultraviolet, VLA radio, and ROSAT X-ray data, where available.”