Spitzer Quasar and ULIRG Evolution Study (QUEST). II. The Spectral Energy Distributions of Palomar-Green Quasars

By H. Netzer, D. Lutz, M. Schweitzer, A. Contursi, E. Sturm, L. Tacconi, Sylvain Veilleux, D.-C. Kim, D. Rupke, A. Baker and 3 more. 2007

287 citations recorded by the source corpus.

This is the second paper studying the QSOs in the Spitzer QUEST sample. Previously we presented new PAH measurements and argued that most of the observed far-infrared (FIR) radiation is due to star-forming activity. Here we present spectral energy distributions (SEDs) by supplementing our data with optical, NIR, and FIR observations. We define two subgroups, of "weak FIR" and "strong FIR" QSOs, and a third group of FIR nondetections. Assuming a starburst origin for the FIR, we obtain "intrinsic" active galactic nucleus (AGN) SEDs by subtracting a starburst template from the mean SEDs. The resulting SEDs are remarkably similar for all groups. They show three distinct peaks corresponding to two silicate emission features and a 3 μm bump, which we interpret as the signature of the hottest AGN dust. They also display drops beyond ~20 μm that we interpret as the signature of the minimum temperature (~200 K) dust. This component must be optically thin to explain the silicate emission and the slope of the long-wavelength continuum. We discuss the merits of an alternative model in which most of the FIR emission is due to AGN heating. Such models are unlikely to explain the properties of our QSOs, but they cannot be ruled out for more luminous objects. We also find correlations between the luminosity at 5100 Å and two infrared starburst indicators: L(60 μm) and L(PAH 7.7 μm). The correlation of L(5100 Å) with L(60 μm) can be used to measure the relative growth rates and lifetimes of the black hole and the new stars.

Subfields: Astronomy and Astrophysics

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In Astronomy and Astrophysics

1. D. M. Alexander
2. P. Hopkins
3. L. Hernquist
4. E. Daddi
5. R. Dav'e
6. R. Somerville
7. D. Elbaz
8. P. V. van Dokkum

Citations in the corpus

• What drives the growth of black holes (2011, background): “Indeed, although the host galaxies of many AGNs are undergoing star-formation activity, there is large scatter in the observed AGN:star formation ratio (e.g., Netzer et al., 2007; Wild et al., 2007; Baum et al., 2010; Diamond-Stanic & Rieke, 2011).”
• COLOR–MAGNITUDE RELATIONS OF ACTIVE AND NON-ACTIVE GALAXIES IN THE CHANDRA DEEP FIELDS: HIGH-REDSHIFT CONSTRAINTS AND STELLAR-MASS SELECTION EFFECTS (2010, background): “Star-formation and active galactic nucleus (i.e., AGN) activity in galaxies are often found to go hand-in-hand (e.g., Page et al. 2001; Alexander et al. 2005b; Netzer et al. 2007; Silverman et al. 2009).”
• The dust content of galaxies from z = 0 to z = 9 (2016, background): “Dust depletes metals from the gas phase ISM (Calzetti, Kinney & Storchi-Bergmann 1994; Calzetti et al. 2000; Netzer et al. 2007; Spoon et al. 2007; Melbourne et al. 2012).”
• Herschel unveils a puzzling uniformity of distant dusty galaxies (2010, background): “…redshifts, hence at large wavelengths, the warm dust continuum heated by the AGN remains negligible at 24 µm (quasar spectra drop beyond ∼20 µm which Netzer et al. 2007 interpret as the signature of a minimum temperature of ∼200 K), the star-formation activity in AGNs could have been associated…”
• Panchromatic spectral energy distributions of Herschel sources (2013, unknown): “The full library comprises a total of roughly 700 models, each one computed at 10 different lines of sight anglesΦ, but we limit the fit toRout/Rin ≤ 100, as extreme values have so far not been confirmed by obser- vations (e.g. Mullaney et al. 2011; Hatziminaoglou et al. 2008; Netzer et al. 2007).”
• STRUCTURE AND FORMATION OF ELLIPTICAL AND SPHEROIDAL GALAXIES (2008, unknown): “1998; Downes & Solomon 1998; Joseph 1999; Rigopoulou et al. 1999; Genzel et al. 2000; Tran et al. 2001; Spoon et al. 2007; Netzer et al. 2007; Vega et al. 2008; Nardini et al. 2008).”
• GOODS–Herschel: an infrared main sequence for star-forming galaxies (2011, background): “…is known that AGN can heat the dust that surrounds them to temperatures of several hundreds of Kelvin and produce a spectrum that can dominate the mid-IR emission of a galaxy, but which typically falls off steeply at wavelengths longer than 20µm (Netzer et al. 2007; see also Mullaney et al. 2011a).”
• A remarkably flat relationship between the average star formation rate and AGN luminosity for distant X-ray AGN. (2015, methodology): “In these bands there could be a contribution from both AGN and star formation, with emission from the AGN peaking at MIR wavelengths and dropping off at the FIR wavelengths (e.g. Netzer et al. 2007; Mullaney et al. 2011).”
• A study of the gas–star formation relation over cosmic time (2010, unknown): “This approach avoids using the mid-infrared luminosity that is more prone to AGN contamination (Netzer et al. 2007).”
• CONSTRAINING EMISSION MODELS OF LUMINOUS BLAZAR SOURCES (2009, background): “On the other hand, we note that the nearIR quasar continua join the harder optical ones almost always around the same frequency, namely ∼1 μm, in both radio-quiet and radio-loud sources (Barvainis 1987; Glikman et al. 2006; Netzer et al. 2007; Labita et al. 2008).”
• ONGOING AND CO-EVOLVING STAR FORMATION IN zCOSMOS GALAXIES HOSTING ACTIVE GALACTIC NUCLEI (2008, background): “…there do appear to be high levels of star formation in the hosts of PG quasars when considering their far-infrared emission (Schweitzer et al. 2006; Netzer et al. 2007), and type 2 quasars from the SDSS (0.3 < z < 0.8; Zakamska et al. 2003; Kim et al. 2006) that may hint at an underlying…”
• Cosmic X-ray surveys of distant active galaxies (2015, background): “…disk is hotter than young stars, the dust is typically heated to higher temperatures (≈ 100–1000 K) and, therefore, the majority of the infrared emission from the AGN is shifted to shorter NIR– MIR wavelengths than that from star formation (≈ 3–30 µm; e.g., Netzer et al 2007; Mullaney et al 2011).”
• FAST MOLECULAR OUTFLOWS IN LUMINOUS GALAXY MERGERS: EVIDENCE FOR QUASAR FEEDBACK FROM HERSCHEL (2013, methodology): “Following V09, the bolometric luminosities for ULIRGs were estimated to be LBOL = 1.15 LIR, where LIR is the infrared luminosity over 8 – 1000 µm (Sanders & Mirabel 1996), and LBOL = 7L(5100 Å)+LIR for the PG QSOs (Netzer et al. 2007).”
• Erratum: Updating quasar bolometric luminosity corrections (2012, background): “Corrections for starlight would be c© 2011 RAS, MNRAS 000, 1–18 necessary at the shortest wavelengths and also for starburstheated dust in the host galaxy (Netzer et al. 2007) at the longest wavelengths, depending on the limits of integration.”
• THE NEXT GENERATION ATLAS OF QUASAR SPECTRAL ENERGY DISTRIBUTIONS FROM RADIO TO X-RAYS (2011, background): “The “FUSE-HST” sample originates with the FUSE AGN program (Kriss 2000), which sur- veyed more than 100 of the UV-brightest AGNs.”
• GOODS-Herschel: the far-infrared view of star formation in active galactic nucleus host galaxies since z ≈ 3 (2011, background): “…(hereafter, FIR) regime is largely impervious to obscuration and, except in the most extreme cases (e.g., Hony et al. 2011), provides a measure of the star formation activity of the host galaxy that is largely uncontaminated by the AGN (e.g., Netzer et al. 2007; Hatziminaoglou et al. 2010).”
• Defining the intrinsic AGN infrared spectral energy distribution and measuring its contribution to the infrared output of composite galaxies (2011, methodology): “When we extrapolate the Netzer et al. (2007) intrinsic quasar SED to longer wavelengths as a modified blackbody and normalise both SEDs at 19µm, then we find that the total power radiated at infrared wavelengths is∼80 per cent that of the average intrinsic infrared SED of typical AGNs calculated…”
• AGN Dusty Tori. II. Observational Implications of Clumpiness (2008, methodology): “One example for the removal of the starburst component is the Netzer et al. (2007) composite SED analysis of the Spitzer observations of PG quasars.”
• Hot graphite dust and the infrared spectral energy distribution of active galactic nuclei (2011, methodology): “Our result is consistent with the shape found by Netzer et al. (2007) for the QUEST sample.”