The Hα luminosity function and star formation rate up to z ∼ 1 |
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| Authors: | L Tresse S J Maddox O Le Fèvre J-G Cuby |
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| Institution: | Laboratoire d'Astrophysique de Marseille, Les Trois-Lucs, B. P. 8, 13376, Marseille Cedex 12, France;School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD;ESO, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19, Chile |
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| Abstract: | We describe ISAAC/ESO-VLT observations of the Hαλ6563 Balmer line of 33 field galaxies from the Canada–France Redshift Survey (CFRS) with redshifts selected between 0.5 and 1.1. We detect Hα in emission in 30 galaxies and compare the properties of this sample with the low-redshift sample of CFRS galaxies at z ∼ 0.2 . We find that the Hα luminosity, L (Hα) , is tightly correlated to M ( B AB) in the same way for both the low- and high-redshift samples. L (Hα) is also correlated to L (O ii ]λ3727), and again the relation appears to be similar at low and high redshifts. The ratio L (lsqb;O ii ])/ L (Hα) decreases for brighter galaxies by as much as a factor of 2 on average. Derived from the Hα luminosity function, the comoving Hα luminosity density increases by a factor 12 from 〈 z 〉= 0.2 to 〈 z 〉= 1.3 . Our results confirm a strong rise of the star formation rate (SFR) at z < 1.3 , proportional to (1 + z )4.1±0.3 (with H 0= 50 km s−1 Mpc−1, q 0= 0.5 ). We find an average SFR(2800 Å)/SFR (Hα) ratio of 3.2 using the Kennicutt SFR transformations. This corresponds to the dust correction that is required to make the near-ultraviolet data consistent with the reddening-corrected Hα data within the self-contained, I -selected CFRS sample. |
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| Keywords: | surveys galaxies: evolution galaxies: luminosity function mass function galaxies: starburst |
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