Luminosity functions for galaxies and quasars in the Spitzer Wide-area Infrared Extragalactic Legacy Survey
Babbedge, T.S.R.; Rowan-Robinson, M.; Vaccari, M.; Surace, J.A.; Lonsdale, C.J.; Clements, D.L.; Fang, F.; Farrah, D.; Franceschini, A.; Gonzalez-Solares, E.; Hatziminaoglou, E.; Lacey, C.G.; Oliver, S.; Onyett, N.; Pérez-Fournon, I.; Polletta, M.; Pozzi, F.; Rodighiero, G.; Shupe, D.L.; Siana, B.; Smith, H.E.
Professor Cedric Lacey firstname.lastname@example.org
We construct rest-frame luminosity functions (LFs) at 3.6, 4.5, 5.8, 8 and 24 μm over the redshift range 0 < z < 2 for galaxies and 0 < z < 4 for optical quasi-stellar objects (QSOs), using optical and infrared (IR) data from the Spitzer Wide-area Infrared Extragalactic (SWIRE) Survey. The 3.6- and 4.5-μm galaxy LFs show evidence for moderate positive luminosity evolution up to z∼ 1.5, consistent with the passive ageing of evolved stellar populations. Their comoving luminosity density was found to evolve passively, gradually increasing out to z∼ 0.5–1 but flattening, or even declining, at higher redshift. Conversely, the 24-μm galaxy LF, which is more sensitive to obscured star formation and/or active galactic nuclei (AGN) activity, undergoes strong positive evolution, with the derived IR energy density and star formation rate (SFR) density ∝ (1 +z)γ with γ= 4.5+0.7−0.6 and the majority of this evolution occurring since z∼ 1. Optical QSOs, however, show positive luminosity evolution in all bands, out to the highest redshifts (3 < z < 4). Modelling as L*∝ (1 +z)γ gave γ= 1.3+0.1−0.1 at 3.6 μm, γ= 1.0+0.1−0.1 at 4.5 μm and stronger evolution at the longer wavelengths (5.8, 8 and 24 μm), of γ∼ 3. Comparison of the galaxy LFs to predictions from a semi-analytic model based on cold dark matter (CDM) indicates that an initial mass function (IMF) skewed towards higher mass star formation in bursts compared to locally be preferred. As a result, the currently inferred massive SFRs in distant submm sources may require substantial downwards revision.
Babbedge, T., Rowan-Robinson, M., Vaccari, M., Surace, J., Lonsdale, C., Clements, D., …Smith, H. (2006). Luminosity functions for galaxies and quasars in the Spitzer Wide-area Infrared Extragalactic Legacy Survey. Monthly Notices of the Royal Astronomical Society, 370(3), 1159-1180. https://doi.org/10.1111/j.1365-2966.2006.10547.x
|Journal Article Type||Article|
|Publication Date||Aug 11, 2006|
|Deposit Date||Jun 27, 2014|
|Publicly Available Date||Jan 29, 2015|
|Journal||Monthly Notices of the Royal Astronomical Society|
|Publisher||Royal Astronomical Society|
|Peer Reviewed||Peer Reviewed|
|Keywords||Galaxies: evolution, Galaxies: photometry, Quasars: general, Cosmology: observations.|
Published Journal Article
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2006 The Authors. Published by Oxford University Press on behalf of The Royal Astronomical Society. All rights reserved.
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