THE MID-INFRARED LUMINOSITY FUNCTION AT z < 0.3 FROM 5MUSES: UNDERSTANDING THE STAR FORMATION/ACTIVE GALACTIC NUCLEUS BALANCE FROM A SPECTROSCOPIC VIEW
- Infrared Processing and Analysis Center, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
- Spitzer Science Center, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
- Department of Physics and Astronomy, University of Wyoming, WY (United States)
- George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843-4242 (United States)
- Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
- Irfu/Service d' Astrophysique, CEA Saclay (France)
We present rest-frame 15 and 24 {mu}m luminosity functions (LFs) and the corresponding star-forming LFs at z < 0.3 derived from the 5MUSES sample. Spectroscopic redshifts have been obtained for {approx}98% of the objects and the median redshift is {approx}0.12. The 5-35 {mu}m 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 {mu}m, and compare with the total 15 and 24 {mu}m 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 {mu}m and 78% at 24 {mu}m, while it goes up to {approx}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 {approx} 0.7 and confirm that evolution on both luminosity and density is required to explain the difference in the LFs at different redshifts.
- OSTI ID:
- 21576669
- Journal Information:
- Astrophysical Journal, Vol. 734, Issue 1; Other Information: DOI: 10.1088/0004-637X/734/1/40; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
THE {approx}0.9 mJy SAMPLE: A MID-INFRARED SPECTROSCOPIC CATALOG OF 150 INFRARED-LUMINOUS, 24 {mu}m SELECTED GALAXIES AT 0.3 {<=} z {<=} 3.5
THE EVOLUTION OF THE STAR FORMATION RATE OF GALAXIES AT 0.0 {<=} z {<=} 1.2