A Bias in Optical Observations of High-Redshift Luminous Infrared Galaxies

Vassilis Charmandaris (1, 2) , E. Le Floc'H (3, 4) , I. Félix Mirabel (3)

1 Department of Astronomy, Cornell University
2 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
3 AIM (UMR_7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
4 Steward Observatory, University of Arizona

We present evidence for the dramatically different morphology between the rest-frame UV and 7 mum mid-IR emission of VV 114 and Arp 299, two nearby (z~0) violently interacting luminous infrared galaxies (LIRGs). Nearly all LIRGs are interacting systems, and it is currently accepted that they dominate the IR emission at z>1. LIRGs located at z=1-2 could easily be detected as unresolved sources in deep optical/near-IR ground-based surveys as well as in upcoming 24 mum surveys with the Space Infrared Telescope Facility. We demonstrate that the spatial resolution of these surveys will result in blending of the emission from unresolved interacting components. An increased scatter will thus be introduced in the observed optical-to-mid-IR colors of these galaxies, leading to a systematic underestimation of their dust content.

Domaines: Astrophysique [astro-ph]

Vassilis Charmandaris, E. Le Floc'H, I. Félix Mirabel. A Bias in Optical Observations of High-Redshift Luminous Infrared Galaxies. The Astrophysical journal letters, 2004, 600, pp.L15-L18. ⟨10.1086/381687⟩. ⟨hal-03742137⟩