Upon its completion the Herschel ATLAS (H-ATLAS) will be the largest submillimetre survey to date, detecting close to half-a-million sources. It will only be possible to measure spectroscopic redshifts for a small fraction of these sources. However, if the rest-frame spectral energy distribution (SED) of a typical H-ATLAS source is known, this SED and the observed Herschel fluxes can be used to estimate the redshifts of the H-ATLAS sources without spectroscopic redshifts. In this paper, we use a subset of 40 H-ATLAS sources with previously measured redshifts in the range 0.5 < z < 4.2 to derive a suitable average template for high redshift H-ATLAS sources. We find that a template with two dust components (Tc = 23.9 K, Th = 46.9 K and ratio of mass of cold dust to mass of warm dust of 30.1) provides a good fit to the rest-frame fluxes of the sources in our calibration sample. We use a jackknife technique to estimate the accuracy of the redshifts estimated with this template, finding a root mean square of Delta z/(1 + z) = 0.26. For sources for which there is prior information that they lie at z > 1 we estimate that the rms of Delta z/(1 + z) = 0.12. We have used this template to estimate the redshift distribution for the sources detected in the H-ATLAS equatorial fields, finding a bimodal distribution with a mean redshift of 1.2, 1.9 and 2.5 for 250, 350 and 500 μm selected sources respectively.

H-ATLAS: Estimating redshifts of herschel sources from sub-mm fluxes / Pearson, E. A.; Eales, S.; Dunne, L.; Gonzalez nuevo, J.; Maddox, S.; Aguirre, J. E.; Baes, M.; Baker, A. J.; Bourne, N.; Bradford, C. M.; Clark, C. J. R.; Cooray, A.; Dariush, A.; De Zotti, Gianfranco; Dye, S.; Frayer, D.; Gomez, H. L.; Harris, A. I.; Hopwood, R.; Ibar, E.; Ivison, R. J.; Jarvis, M.; Krips, M.; Lapi, Andrea; Lupu, R. E.; Michałowski, M. J.; Rosenman, M.; Scott, D.; Valiante, E.; Valtchanov, I.; Van Der Werf, P.; Vieira, J. D.. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 435:4(2013), pp. 2753-2763. [10.1093/mnras/stt1369]

H-ATLAS: Estimating redshifts of herschel sources from sub-mm fluxes

De Zotti, Gianfranco;Lapi, Andrea;
2013

Abstract

Upon its completion the Herschel ATLAS (H-ATLAS) will be the largest submillimetre survey to date, detecting close to half-a-million sources. It will only be possible to measure spectroscopic redshifts for a small fraction of these sources. However, if the rest-frame spectral energy distribution (SED) of a typical H-ATLAS source is known, this SED and the observed Herschel fluxes can be used to estimate the redshifts of the H-ATLAS sources without spectroscopic redshifts. In this paper, we use a subset of 40 H-ATLAS sources with previously measured redshifts in the range 0.5 < z < 4.2 to derive a suitable average template for high redshift H-ATLAS sources. We find that a template with two dust components (Tc = 23.9 K, Th = 46.9 K and ratio of mass of cold dust to mass of warm dust of 30.1) provides a good fit to the rest-frame fluxes of the sources in our calibration sample. We use a jackknife technique to estimate the accuracy of the redshifts estimated with this template, finding a root mean square of Delta z/(1 + z) = 0.26. For sources for which there is prior information that they lie at z > 1 we estimate that the rms of Delta z/(1 + z) = 0.12. We have used this template to estimate the redshift distribution for the sources detected in the H-ATLAS equatorial fields, finding a bimodal distribution with a mean redshift of 1.2, 1.9 and 2.5 for 250, 350 and 500 μm selected sources respectively.
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Pearson, E. A.; Eales, S.; Dunne, L.; Gonzalez nuevo, J.; Maddox, S.; Aguirre, J. E.; Baes, M.; Baker, A. J.; Bourne, N.; Bradford, C. M.; Clark, C. J. R.; Cooray, A.; Dariush, A.; De Zotti, Gianfranco; Dye, S.; Frayer, D.; Gomez, H. L.; Harris, A. I.; Hopwood, R.; Ibar, E.; Ivison, R. J.; Jarvis, M.; Krips, M.; Lapi, Andrea; Lupu, R. E.; Michałowski, M. J.; Rosenman, M.; Scott, D.; Valiante, E.; Valtchanov, I.; Van Der Werf, P.; Vieira, J. D.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11767/17446
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