Wu, Yanling and Shi, Yong and Helou, George and Armus, Lee and Dale, Daniel A. and Papovich, Casey and Rahman, Nurur and Dasyra, Kalliopi and Stierwalt, Sabrina (2011) The Mid-infrared Luminosity Function at z < 0.3 from 5MUSES: Understanding the Star Formation/Active Galactic Nucleus Balance from a Spectroscopic View. Astrophysical Journal, 734 (1). Art. No. 40. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20110610-142036267
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We present rest-frame 15 and 24 μm luminosity functions (LFs) and the corresponding star-forming LFs at z < 0.3 derived from the 5MUSES sample. Spectroscopic redshifts have been obtained for ~98% of the objects and the median redshift is ~0.12. The 5-35 μm Infrared Spectrograph spectra allow us to estimate accurately the luminosities and build the LFs. Using a combination of starburst and quasar templates, we quantify the star formation (SF) and active galactic nucleus (AGN) contributions in the mid-IR spectral energy distribution. We then compute the SF LFs at 15 and 24 μm, and compare with the total 15 and 24 μm LFs. When we remove the contribution of AGNs, the bright end of the LF exhibits a strong decline, consistent with the exponential cutoff of a Schechter function. Integrating the differential LF, we find that the fractional contribution by SF to the energy density is 58% at 15 μm and 78% at 24 μm, while it goes up to ~86% when we extrapolate our mid-IR results to the total IR luminosity density. We confirm that the AGNs play more important roles energetically at high luminosities. Finally, we compare our results with work at z ~ 0.7 and confirm that evolution on both luminosity and density is required to explain the difference in the LFs at different redshifts.
|Additional Information:||© 2011 The American Astronomical Society. Received 2010 December 7; accepted 2011 April 1; published 2011 May 24. We thank J.-S. Huang, V. Charmandaris, H. Fu, and E. Le Floc’h for insightful discussion. This work was based on observations made with the Spitzer Space Telescope, which is operated by JPL/Caltech under a contract with NASA. The observations are associated with the Spitzer Legacy Program 40539. The authors acknowledge support by NASA through awards issued by JPL/Caltech. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.|
|Subject Keywords:||galaxies: active; galaxies: luminosity function, mass function; galaxies: starburst; infrared: galaxies|
|Classification Code:||PACS: 97.10.Bt; 98.54.Ep; 98.62.Qz; 98.62.Py; 95.85.Hp; 98.54.Aj|
|Official Citation:||The Mid-infrared Luminosity Function at z < 0.3 from 5MUSES: Understanding the Star Formation/Active Galactic Nucleus Balance from a Spectroscopic View Yanling Wu, Yong Shi, George Helou, Lee Armus, Daniel A. Dale, Casey Papovich, Nurur Rahman, Kalliopi Dasyra and Sabrina Stierwalt doi: 10.1088/0004-637X/734/1/40|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||10 Jun 2011 22:22|
|Last Modified:||26 Dec 2012 13:18|
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