Spectral Energy Distributions of type 2 QSOs: obscured star formation at high redshifts
We present new mid-infrared and submillimetre observations for a sample of eight high redshift type-2 QSOs located in the Chandra Deep Field South. The sources are X-ray absorbed with luminosities in excess of 10^44 erg/s. Two of the targets have robust detections, S/N > 4, while a further th...
| Main Authors: | , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2009
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| _version_ | 1797069504563380224 |
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| author | Rigopoulou, D Mainieri, V Almaini, O Alonso-Herrero, A Huang, J Hasinger, G Rieke, G Dunlop, J Lehmann, I |
| author_facet | Rigopoulou, D Mainieri, V Almaini, O Alonso-Herrero, A Huang, J Hasinger, G Rieke, G Dunlop, J Lehmann, I |
| author_sort | Rigopoulou, D |
| collection | OXFORD |
| description | We present new mid-infrared and submillimetre observations for a sample of eight high redshift type-2 QSOs located in the Chandra Deep Field South. The sources are X-ray absorbed with luminosities in excess of 10^44 erg/s. Two of the targets have robust detections, S/N > 4, while a 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 submillimetre 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>10^12Lsun. The submillimetre (850micron) to X-ray (2 keV) spectral indices (alpha_SX) span a wide range. About half of the type-2 QSOs have values typical for a Compton-thick AGN 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. |
| first_indexed | 2024-03-06T22:25:26Z |
| format | Journal article |
| id | oxford-uuid:5685c3dc-84f0-485b-9277-65c71b74063d |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T22:25:26Z |
| publishDate | 2009 |
| record_format | dspace |
| spelling | oxford-uuid:5685c3dc-84f0-485b-9277-65c71b74063d2022-03-26T16:50:45ZSpectral Energy Distributions of type 2 QSOs: obscured star formation at high redshiftsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:5685c3dc-84f0-485b-9277-65c71b74063dEnglishSymplectic Elements at Oxford2009Rigopoulou, DMainieri, VAlmaini, OAlonso-Herrero, AHuang, JHasinger, GRieke, GDunlop, JLehmann, IWe present new mid-infrared and submillimetre observations for a sample of eight high redshift type-2 QSOs located in the Chandra Deep Field South. The sources are X-ray absorbed with luminosities in excess of 10^44 erg/s. Two of the targets have robust detections, S/N > 4, while a 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 submillimetre 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>10^12Lsun. The submillimetre (850micron) to X-ray (2 keV) spectral indices (alpha_SX) span a wide range. About half of the type-2 QSOs have values typical for a Compton-thick AGN 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. |
| spellingShingle | Rigopoulou, D Mainieri, V Almaini, O Alonso-Herrero, A Huang, J Hasinger, G Rieke, G Dunlop, J Lehmann, I Spectral Energy Distributions of type 2 QSOs: obscured star formation at high redshifts |
| title | Spectral Energy Distributions of type 2 QSOs: obscured star formation at
high redshifts |
| title_full | Spectral Energy Distributions of type 2 QSOs: obscured star formation at
high redshifts |
| title_fullStr | Spectral Energy Distributions of type 2 QSOs: obscured star formation at
high redshifts |
| title_full_unstemmed | Spectral Energy Distributions of type 2 QSOs: obscured star formation at
high redshifts |
| title_short | Spectral Energy Distributions of type 2 QSOs: obscured star formation at
high redshifts |
| title_sort | spectral energy distributions of type 2 qsos obscured star formation at high redshifts |
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