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Title: THE EVOLVING INTERSTELLAR MEDIUM OF STAR-FORMING GALAXIES SINCE z = 2 AS PROBED BY THEIR INFRARED SPECTRAL ENERGY DISTRIBUTIONS

Abstract

Using data from the mid-infrared to millimeter wavelengths for individual galaxies and for stacked ensembles at 0.5 < z < 2, we derive robust estimates of dust masses (M {sub dust}) for main-sequence (MS) galaxies, which obey a tight correlation between star formation rate (SFR) and stellar mass (M {sub *}), and for starbursting galaxies that fall outside that relation. Exploiting the correlation of gas-to-dust mass with metallicity (M {sub gas}/M {sub dust}-Z), we use our measurements to constrain the gas content, CO-to-H{sub 2} conversion factors ({alpha}{sub CO}), and star formation efficiencies (SFE) of these distant galaxies. Using large statistical samples, we confirm that {alpha}{sub CO} and SFE are an order of magnitude higher and lower, respectively, in MS galaxies at high redshifts compared to the values of local galaxies with equivalently high infrared luminosities (L {sub IR} > 10{sup 12} L {sub Sun }). For galaxies within the MS, we show that the variations of specific star formation rates (sSFRs = SFR/M {sub *}) are driven by varying gas fractions. For relatively massive galaxies like those in our samples, we show that the hardness of the radiation field, (U), which is proportional to the dust-mass-weighted luminosity (L {sub IR}/Mmore » {sub dust}) and the primary parameter defining the shape of the IR spectral energy distribution (SED), is equivalent to SFE/Z. For MS galaxies with stellar mass log (M {sub *}/M {sub Sun }) {>=} 9.7 we measure this quantity, (U), showing that it does not depend significantly on either the stellar mass or the sSFR. This is explained as a simple consequence of the existing correlations between SFR-M {sub *}, M {sub *}-Z, and M {sub gas}-SFR. Instead, we show that (U) (or equally L {sub IR}/M {sub dust}) does evolve, with MS galaxies having harder radiation fields and thus warmer temperatures as redshift increases from z = 0 to 2, a trend that can also be understood based on the redshift evolution of the M {sub *}-Z and SFR-M {sub *} relations. These results motivate the construction of a universal set of SED templates for MS galaxies that are independent of their sSFR or M {sub *} but vary as a function of redshift with only one parameter, (U).« less

Authors:
;  [1]; ; ; ; ;  [2]; ;  [3];  [4]; ;  [5];  [6];  [7]
  1. Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)
  2. CEA, Laboratoire AIM, Irfu/SAp, F-91191 Gif-sur-Yvette (France)
  3. NOAO, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)
  4. Institut fuer Astronophysik, Universitaet Wien, Tuerkenschanzstrasse 17, A-1180 Wien (Austria)
  5. Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)
  6. Department of Physics and ICTP, University of Crete, GR-71003, Heraklion (Greece)
  7. Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22086387
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 760; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; CONVERSION; CORRELATIONS; COSMIC DUST; ENERGY SPECTRA; GALACTIC EVOLUTION; HYDROGEN; INFRARED SPECTRA; LUMINOSITY; MASS; MILKY WAY; RED SHIFT; STARS

Citation Formats

Magdis, Georgios E, Rigopoulou, D, Daddi, E, Bethermin, M, Sargent, M, Elbaz, D, Pannella, M, Dickinson, M, Kartaltepe, J, Dannerbauer, H, Da Cunha, E, Walter, F, Charmandaris, V, and Hwang, H S. THE EVOLVING INTERSTELLAR MEDIUM OF STAR-FORMING GALAXIES SINCE z = 2 AS PROBED BY THEIR INFRARED SPECTRAL ENERGY DISTRIBUTIONS. United States: N. p., 2012. Web. doi:10.1088/0004-637X/760/1/6.
Magdis, Georgios E, Rigopoulou, D, Daddi, E, Bethermin, M, Sargent, M, Elbaz, D, Pannella, M, Dickinson, M, Kartaltepe, J, Dannerbauer, H, Da Cunha, E, Walter, F, Charmandaris, V, & Hwang, H S. THE EVOLVING INTERSTELLAR MEDIUM OF STAR-FORMING GALAXIES SINCE z = 2 AS PROBED BY THEIR INFRARED SPECTRAL ENERGY DISTRIBUTIONS. United States. https://doi.org/10.1088/0004-637X/760/1/6
Magdis, Georgios E, Rigopoulou, D, Daddi, E, Bethermin, M, Sargent, M, Elbaz, D, Pannella, M, Dickinson, M, Kartaltepe, J, Dannerbauer, H, Da Cunha, E, Walter, F, Charmandaris, V, and Hwang, H S. 2012. "THE EVOLVING INTERSTELLAR MEDIUM OF STAR-FORMING GALAXIES SINCE z = 2 AS PROBED BY THEIR INFRARED SPECTRAL ENERGY DISTRIBUTIONS". United States. https://doi.org/10.1088/0004-637X/760/1/6.
@article{osti_22086387,
title = {THE EVOLVING INTERSTELLAR MEDIUM OF STAR-FORMING GALAXIES SINCE z = 2 AS PROBED BY THEIR INFRARED SPECTRAL ENERGY DISTRIBUTIONS},
author = {Magdis, Georgios E and Rigopoulou, D and Daddi, E and Bethermin, M and Sargent, M and Elbaz, D and Pannella, M and Dickinson, M and Kartaltepe, J and Dannerbauer, H and Da Cunha, E and Walter, F and Charmandaris, V and Hwang, H S},
abstractNote = {Using data from the mid-infrared to millimeter wavelengths for individual galaxies and for stacked ensembles at 0.5 < z < 2, we derive robust estimates of dust masses (M {sub dust}) for main-sequence (MS) galaxies, which obey a tight correlation between star formation rate (SFR) and stellar mass (M {sub *}), and for starbursting galaxies that fall outside that relation. Exploiting the correlation of gas-to-dust mass with metallicity (M {sub gas}/M {sub dust}-Z), we use our measurements to constrain the gas content, CO-to-H{sub 2} conversion factors ({alpha}{sub CO}), and star formation efficiencies (SFE) of these distant galaxies. Using large statistical samples, we confirm that {alpha}{sub CO} and SFE are an order of magnitude higher and lower, respectively, in MS galaxies at high redshifts compared to the values of local galaxies with equivalently high infrared luminosities (L {sub IR} > 10{sup 12} L {sub Sun }). For galaxies within the MS, we show that the variations of specific star formation rates (sSFRs = SFR/M {sub *}) are driven by varying gas fractions. For relatively massive galaxies like those in our samples, we show that the hardness of the radiation field, (U), which is proportional to the dust-mass-weighted luminosity (L {sub IR}/M {sub dust}) and the primary parameter defining the shape of the IR spectral energy distribution (SED), is equivalent to SFE/Z. For MS galaxies with stellar mass log (M {sub *}/M {sub Sun }) {>=} 9.7 we measure this quantity, (U), showing that it does not depend significantly on either the stellar mass or the sSFR. This is explained as a simple consequence of the existing correlations between SFR-M {sub *}, M {sub *}-Z, and M {sub gas}-SFR. Instead, we show that (U) (or equally L {sub IR}/M {sub dust}) does evolve, with MS galaxies having harder radiation fields and thus warmer temperatures as redshift increases from z = 0 to 2, a trend that can also be understood based on the redshift evolution of the M {sub *}-Z and SFR-M {sub *} relations. These results motivate the construction of a universal set of SED templates for MS galaxies that are independent of their sSFR or M {sub *} but vary as a function of redshift with only one parameter, (U).},
doi = {10.1088/0004-637X/760/1/6},
url = {https://www.osti.gov/biblio/22086387}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 760,
place = {United States},
year = {Tue Nov 20 00:00:00 EST 2012},
month = {Tue Nov 20 00:00:00 EST 2012}
}