Infrared photometry of z~1 3C quasars
We present JHKL' photometry of a complete sample of steep-spectrum radio-loud quasars from the revised 3CR catalogue in the redshift range 0.65 < z < 1.20. After correcting for contributions from emission lines and the host galaxies, we investigate their spectral energy distributi...
| Main Authors: | , |
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| Format: | Journal article |
| Published: |
2000
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| _version_ | 1797061827825238016 |
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| author | Simpson, C Rawlings, S |
| author_facet | Simpson, C Rawlings, S |
| author_sort | Simpson, C |
| collection | OXFORD |
| description | We present JHKL' photometry of a complete sample of steep-spectrum radio-loud quasars from the revised 3CR catalogue in the redshift range 0.65 < z < 1.20. After correcting for contributions from emission lines and the host galaxies, we investigate their spectral energy distributions (SEDs) around 1 micron. About 75% of the quasars are tightly grouped in the plane of optical spectral index, alpha_lo, versus near-infrared spectral index, alpha_hi, with the median value of alpha_lo close to the canonical value, and the median alpha_hi slightly flatter. We conclude that the fraction of moderately-obscured, red quasars decreases with increasing radio power, in accordance with the `receding torus' model which can also explain the relatively flat median near-infrared spectra of the 3CR quasars. Two of the red quasars have inverted infrared spectral indices, and we suggest that their unusual SEDs might result from a combination of dust-scattered and transmitted quasar light. |
| first_indexed | 2024-03-06T20:36:44Z |
| format | Journal article |
| id | oxford-uuid:32e7d57b-8ddf-465f-8882-7166d7393da1 |
| institution | University of Oxford |
| last_indexed | 2024-03-06T20:36:44Z |
| publishDate | 2000 |
| record_format | dspace |
| spelling | oxford-uuid:32e7d57b-8ddf-465f-8882-7166d7393da12022-03-26T13:16:51ZInfrared photometry of z~1 3C quasarsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:32e7d57b-8ddf-465f-8882-7166d7393da1Symplectic Elements at Oxford2000Simpson, CRawlings, SWe present JHKL' photometry of a complete sample of steep-spectrum radio-loud quasars from the revised 3CR catalogue in the redshift range 0.65 < z < 1.20. After correcting for contributions from emission lines and the host galaxies, we investigate their spectral energy distributions (SEDs) around 1 micron. About 75% of the quasars are tightly grouped in the plane of optical spectral index, alpha_lo, versus near-infrared spectral index, alpha_hi, with the median value of alpha_lo close to the canonical value, and the median alpha_hi slightly flatter. We conclude that the fraction of moderately-obscured, red quasars decreases with increasing radio power, in accordance with the `receding torus' model which can also explain the relatively flat median near-infrared spectra of the 3CR quasars. Two of the red quasars have inverted infrared spectral indices, and we suggest that their unusual SEDs might result from a combination of dust-scattered and transmitted quasar light. |
| spellingShingle | Simpson, C Rawlings, S Infrared photometry of z~1 3C quasars |
| title | Infrared photometry of z~1 3C quasars |
| title_full | Infrared photometry of z~1 3C quasars |
| title_fullStr | Infrared photometry of z~1 3C quasars |
| title_full_unstemmed | Infrared photometry of z~1 3C quasars |
| title_short | Infrared photometry of z~1 3C quasars |
| title_sort | infrared photometry of z 1 3c quasars |
| work_keys_str_mv | AT simpsonc infraredphotometryofz13cquasars AT rawlingss infraredphotometryofz13cquasars |