2005/09/02 by D. Lutz, L. Yan, Lin Yan +6 · 41 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminous infrared galaxy #Millimeter #Physics #Population #Redshift #Spectral energy distribution #Star formation #astro-ph
paper · pdf · doi:10.1086/497639
published in The Astrophysical Journal 632(1), L13-L16 (IOP Publishing) · 15 pages, 4 eps figures. Accepted for publication as an ApJ Letter
arxiv created 2005/09/02 · openalex publication_date 2005/09/29 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We present MAMBO 1.2 mm observations of 40 extragalactic sources from the Spitzer First Look Survey that are bright in the mid-IR ( S 24 μm > 1 mJy) but optically obscured (log > 1). We use these observations to search for cold dust emission, probing the similarity of their spectral energy distributions to star-forming IR galaxies or obscured AGNs. The sample as a whole is well detected at mean S 1.2 mm = 0.74 ± 0.09 mJy and S 1.2 mm / S 24 μm = 0.15 ± 0.03. Seven (three) of the sources are individually detected at >3 σ (>5 σ) levels. Mean millimeter fluxes are higher for sources with the reddest mid-IR/optical colors. Optically faint but with relatively low millimeter-to-mid-IR ratios, the typical SEDs are inconsistent with redshifted SED shapes of local star-forming IR galaxies. They also differ from SEDs of typical submillimeter-selected galaxies, with the 24 μm sources that are individually detected by MAMBO possibly representing intermediate objects. Compared to star-forming galaxies, a stronger but optically obscured mid-IR component without associated strong far-IR emission has to be included. This component may be due to luminous optically obscured AGN, which would represent a significant part of the high-redshift AGN population.