Dust temperature and the submillimetre–radio flux density ratio as a redshift indicator for distant galaxies |
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| Authors: | A W Blain |
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| Institution: | Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE |
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| Abstract: | It is difficult to identify the distant galaxies selected in existing submillimetre-wave surveys, because their positions are known at best to only several arcsec. Centimetre-wave VLA observations are required in order to determine positions to subarcsec accuracy, and so to allow reliable optical identifications to be made. Carilli & Yun pointed out that the ratio of the radio to submillimetre-wave flux densities provides a redshift indicator for dusty star-forming galaxies, when compared with the tight correlation between the far-infrared and radio flux densities observed in low-redshift galaxies. This method does provide a useful, albeit imprecise, indication of the distance to a submillimetre-selected galaxy. Unfortunately, it does not provide an unequivocal redshift estimate, as the degeneracy between the effects of increasing the redshift of a galaxy and decreasing its dust temperature is not broken. |
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| Keywords: | dust extinction galaxies: distances and redshifts galaxies: general galaxies: starburst infrared: galaxies radio continuum: galaxies |
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