2010/05/03 by J. R. Houck, James R. Houck, Houck, James R. +3
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph.CO
paper · pdf · doi:10.48550/arxiv.1005.0344
To appear in "Reionization to Exoplanets: Spitzer's Growing Legacy", ASP Conference Series, ed: P. Ogle
arxiv created 2010/05/03 · openalex publication_date 2010/05/03 · arxiv updated 2010/05/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
We summarize observations with the Spitzer Infrared Spectrograph (IRS) of 571\nstarbursts (strong PAH emission features), 128 obscured AGN (strong silicate\nabsorption), and 39 unobscured AGN (silicate emission). Sources range in\nluminosity from 108 to 1014 solar luminosities and continuously in\nredshift for 0 < z < 3. The most luminous starbursts and AGN evolve as\n(1+z)2.5 to z ~ 2.5; no clear evidence is found that this evolution ceases\nbeyond z = 2.5. Dust obscuration in starbursts is determined by comparing PAH\nluminosity with ultraviolet luminosity and indicates severe obscuration in most\nstarbursts, even those selected in the ultraviolet; the median ratio (intrinsic\nultraviolet/observed ultraviolet) is ~ 50 for infrared selected starbursts and\n~ 8 for ultraviolet selected starbursts. Obscuration increases with bolometric\nluminosity, but starbursts which appear most luminous in the ultraviolet are\nthose with the least obscuration. This result indicates that extinction\ncorrections are significantly underestimated for ultraviolet selected sources,\nsuggesting that galaxies at z ~> 2 are more luminous than deduced only from\nrest frame ultraviolet observations.\n