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Persistent URL http://purl.org/net/epubs/work/10919969
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Record Id 10919969
Title Spectral energy distributions of type 2 quasi-stellar objects: Obscured star formation at high redshifts
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Abstract We present new mid-infrared and submillimetre observations for a sample of eight high-redshift type 2 quasi-stellar objects (QSOs) located in the Chandra Deep Field-South. The sources are X-ray absorbed with luminosities in excess of 10 erg s. Two of the targets have robust detections, S/N > 4, while further three targets are marginally detected with S/N ? 2.5. All sources are detected in multiple mid-infrared bands with the Spitzer Space Telescope. The multiwavelength spectral energy distributions (SEDs) of the type 2 QSOs are compared to those of two local ultraluminous galaxies (Arp220 and IR22491) in order to assess contributions from a star-forming component in various parts of the SED. We suggest that their submm emission is possibly due to a starburst while a large fraction of the mid-infrared energy is likely to originate in the obscured central quasar. Using the mid-infrared and submm observations, we derive infrared luminosities which are found to be in excess of L > 10 L. The submm (850 ?m) to X-ray (2 keV) spectral indices (?) span a wide range. About half of the type 2 QSOs have values typical for a Compton-thick active galactic nuclei with only 1 per cent of the nuclear emission seen through scattering, and the remaining with values typical of submm-bright galaxies. Combining the available observational evidence, we outline a possible scenario for the early stages of evolution of these sources. © 2009 RAS.
Organisation SSTD , STFC , RALSP - SPD
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Language English (EN)
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Journal Article Mon Notic Roy Astron Soc 400 (2009): 1199-1207. doi:10.1111/j.1365-2966.2009.15543.x 2009