Spitzer Quasar and ULIRG Evolution Study (QUEST). I. The Origin of the Far-Infrared Continuum of QSOs

By M. Schweitzer, D. Lutz, E. Sturm, A. Contursi, L. Tacconi, M. Lehnert, K. Dasyra, R. Genzel, Sylvain Veilleux, D. Rupke and 6 more. 2006

209 citations recorded by the source corpus.

This paper addresses the origin of the far-infrared (FIR) continuum of QSOs, based on the Quasar and ULIRG Evolution Study (QUEST) of nearby QSOs and ULIRGs using observations with the Spitzer Space Telescope. For 27 Palomar-Green QSOs at z ≲ 0.3, we derive luminosities of diagnostic lines ([Ne II] 12.8 μm, [Ne V] 14.3 μm, [O IV] 25.9 μm) and emission features (PAH 7.7 μm emission, which is related to star formation), as well as continuum luminosities over a range of mid- to far-infrared wavelengths between 6 and 60 μm. We detect star-formation-related PAH emission in 11/26 QSOs and fine-structure line emission in all of them, often in multiple lines. The detection of PAHs in the average spectrum of sources that lack individual PAH detections provides further evidence for the widespread presence of PAHs in QSOs. Similar PAH/FIR and [Ne II]/FIR ratios are found in QSOs and in starburst-dominated ULIRGs and lower luminosity starbursts. We conclude that the typical QSO in our sample has at least 30% but likely most of the far-infrared luminosity (~1010-1012 L☉) arising from star formation, with a tendency for larger star formation contribution at the largest FIR luminosities. In the QSO sample, we find correlations between most of the quantities studied including combinations of AGN tracers and starburst tracers. The common scaling of AGN and starburst luminosities (and fluxes) is evidence for a starburst-AGN connection in luminous AGN. Strong correlations of far-infrared continuum and starburst related quantities (PAH, low-excitation [Ne II]) offer additional support for the starburst origin of far-infrared emission.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/a6ca8c7ed12524ca94a0f74f9dd8e6e6a66801ca

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In Astronomy and Astrophysics

1. D. M. Alexander
2. L. Hernquist
3. P. Hopkins
4. H. Netzer
5. R. Dav'e
6. E. Daddi
7. Thomas J. Cox
8. P. V. van Dokkum

Citations in the corpus

• A 158 μm [C ii] LINE SURVEY OF GALAXIES AT z ∼ 1–2: AN INDICATOR OF STAR FORMATION IN THE EARLY UNIVERSE (2010, background): “Schweitzer et al. (2006) find that the PAH/FIR and [Ne ii]/FIR ratios within their AGN sample are similar to those of a starburst dominated ULIRG sample.”
• Dust covering factor, silicate emission, and star formation in luminous QSOs (2007, methodology): “The Schweitzer et al. (2006) sample is also used for the investigation of the MIR-to-optical luminosity ratio.”
• Evidence for Merger Remnants in Early-Type Host Galaxies of Low-Redshift QSOs (2008, background): “…AGNs are bulge-dominated, they seem to be significantly bluer than inactive elliptical galaxies, and indeed show evidence for starbursts in the relatively recent past (1–2 Gyr; e.g., Kauffmann et al. 2003; Sánchez et al. 2004; Canalizo et al. 2006; Schweitzer et al. 2006; Jahnke et al. 2007).”
• DETECTION OF ATOMIC CARBON [C ii] 158 μm AND DUST EMISSION FROM A z = 7.1 QUASAR HOST GALAXY (2012, background): “Studies of lower redshift quasars found fractions ranging from 25% (e.g. Shi et al. 2007), >30%–100% (e.g. Schweitzer et al. 2006) to >50% (e.g. Walter et al. 2009).”
• Spitzer Quasar and ULIRG Evolution Study (QUEST). II. The Spectral Energy Distributions of Palomar-Green Quasars (2007, background): “This has been discussed extensively in our first paper (Schweitzer et al. 2006, hereafter paper I) where many relevant references are listed, and it is also a major topic of the present work.”
• Star Formation in the Hosts of High-z QSOs: Evidence from Spitzer PAH Detections (2008, methodology): “PAH 7.7µm fluxes listed in Table 2 can thus be directly compared to the results for local QSOs presented by Schweitzer et al. (2006).”
• Enhanced star formation rates in AGN hosts with respect to inactive galaxies from PEP-Herschel observations (2012, background): “(Rowan-Robinson 1995; Schweitzer et al. 2006; Netzer et al. 2007; Lutz et al. 2008; Bonfield et al. 2011).”
• ONGOING AND CO-EVOLVING STAR FORMATION IN zCOSMOS GALAXIES HOSTING ACTIVE GALACTIC NUCLEI (2008, background): “However, 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…”
• The Distribution of Silicate Strength in Spitzer Spectra of AGNs and ULIRGs (2006, background): “…emission lines from [Siv] 10.5 mm, [Ne ii] 12.8 mm, [Ne v] 14.3mm, [Ne iii] 15.5 mm, [S iii] 18.7 mm, [Ne v] 24.3 mm, and [O iv] 25.9 mm. PAH emission is also detected in the average spectrum of PG quasars, even for those that do not show PAHs in their individual spectra (Schweitzer et al. 2006).”
• Accretion and star formation rates in low‐redshift type II active galactic nuclei (2009, background): “PAH-based and FIR-based estimates of LSF in low and high redshift, high luminosity type-I AGN are described in Schweitzer et al. (2006), Netzer et al. (2007), Schweitzer et al. (2008) and Lutz et al. (2008).”
• STRUCTURE AND FORMATION OF ELLIPTICAL AND SPHEROIDAL GALAXIES (2008, background): “AGNs are seen to be more important in more luminous ULIRGs (Lutz et al. 1998; Genzel et al. 2000; Tran et al. 2001; Farrah et al. 2002; Veilleux et al. 2006; Schweitzer et al. 2006; Netzer et al. 200).”
• Hot graphite dust and the infrared spectral energy distribution of active galactic nuclei (2011, methodology): “The Spitzer observations and the data reduction procedure of the S10 and QUEST samples are detailed in S10 and Schweitzer et al. (2006), respectively and are summarized here for completion.”
• Mid-Infrared Spectral Diagnosis of Submillimeter Galaxies (2007, background): “Schweitzer et al. (2006) showed that a similar correlation exists in a sample of QSOs due to star formation in them.”
• THE NEXT GENERATION ATLAS OF QUASAR SPECTRAL ENERGY DISTRIBUTIONS FROM RADIO TO X-RAYS (2011, background): “Schweitzer et al. (2006) and Netzer et al. (2007) studied Palomar-Green quasars with FIR to optical data and confirmed that most FIR radiation is due to star-forming activity.”