Morphology and size differences between local and high-redshift luminous infrared galaxies

Wiphu Rujopakarn, George H. Rieke, Daniel J. Eisenstein, St́ephanie Juneau

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


We show that the star-forming regions in high-redshift luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) and submillimeter galaxies (SMGs) have similar physical scales to those in local normal star-forming galaxies. To first order, their higher infrared (IR) luminosities result from higher luminosity surface density. We also find a good correlation between the IR luminosity and IR luminosity surface density in starburst galaxies across over five orders of magnitude of IR luminosity from local normal galaxies to z ∼ 2 SMGs. The intensely star-forming regions of local ULIRGs are significantly smaller than those in their high-redshift counterparts and hence diverge significantly from this correlation, indicating that the ULIRGs found locally are a different population from the high-redshift ULIRGs and SMGs. Based on this relationship, we suggest that luminosity surface density should serve as a more accurate indicator for the IR emitting environment, and hence the observable properties, of star-forming galaxies than their IR luminosity. We demonstrate this approach by showing that ULIRGs at z ∼ 1 and a lensed galaxy at z ∼ 2.5 exhibit aromatic features agreeing with local LIRGs that are an order of magnitude less luminous, but have similar IR luminosity surface density. A consequence of this relationship is that the aromatic emission strength in star-forming galaxies will appear to increase at z > 1 for a given IR luminosity compared to their local counterparts.

Original languageEnglish (US)
JournalAstrophysical Journal
Issue number2
StatePublished - Jan 10 2011


  • Galaxies: evolution
  • Galaxies: high-redshift
  • Galaxies: starburst
  • Galaxies: structure
  • Infrared: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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