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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 710006.0, MPI für Astronomie / Publikationen_mpia
Infrared spectra and photometry of complete samples of Palomar-Green and two micron All Sky Survey quasars
Authors:Shi, Y.; Rieke, G. H.; Ogle, P. M.; Su, K. Y. L.; Balog, Z.
Date of Publication (YYYY-MM-DD):2014
Title of Journal:The Astrophysical Journal Supplement Series
Issue / Number:2
Start Page:id. 23 (17 pp)
Audience:Not Specified
Abstract / Description:As a step toward a comprehensive overview of the infrared (IR) diagnostics of the central engines and host galaxies of quasars at low redshift, we present Spitzer Space Telescope spectroscopic (5-40 mum) and photometric (24, 70, and 160 mum) measurements of all Palomar-Green (PG) quasars at z < 0.5 and Two Micron All Sky Survey (2MASS) quasars at z < 0.3. We supplement these data with Herschel measurements at 160 mum. The sample is composed of 87 optically selected PG quasars and 52 near-IR-selected 2MASS quasars. Here we present the data, measure the prominent spectral features, and separate emission due to star formation from that emitted by the dusty circumnuclear torus. We find that the mid-IR (5-30 mum) spectral shape for the torus is largely independent of quasar IR luminosity with scatter in the spectral energy distribution (SED) shape of lsim0.2 dex. Except for the silicate features, no large difference is observed between PG (unobscured---silicate emission) and 2MASS (obscured---silicate absorption) quasars. Only mild silicate features are observed in both cases. When in emission, the peak wavelength of the silicate feature tends to be longer than 9.7 mum, possibly indicating effects on grain properties near the active galactic nucleus. The IR color is shown to correlate with the equivalent width of the aromatic features, indicating that the slope of the quasar mid- to far-IR SED is to first order driven by the fraction of radiation from star formation in the IR bands.
Free Keywords:galaxies: active; galaxies: starburst; infrared: galaxies
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0067-0049 %R 10.1088/0067-0049/214/2/23
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