We describe ISAAC/ESO-VLT observations of the H \alpha \lambda 6563 Balmer line of 33 field galaxies from the Canada-France Redshift Survey ( CFRS ) with redshifts selected between 0.5 and 1.1 .
We detect H \alpha in emission in 30 galaxies and compare the properties of this sample with the low-redshift sample of CFRS galaxies at z \sim 0.2 [ Tresse & Maddox 1998 ] .
We find that the H \alpha luminosity , L ( H \alpha ) , is tightly correlated to M ( B _ { \mathrm { AB } } ) in the same way for both the low- and high-redshift samples .
L ( H \alpha ) is also correlated to L ( [ O II ] \lambda 3727 ) , and again the relation appears to be similar at low and high redshifts .
The ratio L ( [ O II ] ) /L ( H \alpha ) decreases for brighter galaxies by as much as a factor 2 on average .
Derived from the H \alpha luminosity function , the comoving H \alpha luminosity density increases by a factor 12 from \langle z \rangle = 0.2 to \langle z \rangle = 1.3 .
Our results confirm a strong rise of the star formation rate ( SFR ) at z < 1.3 , proportional to ( 1 + z ) ^ { 4.1 \pm 0.3 } ( with H _ { 0 } = 50 km s ^ { -1 } Mpc ^ { -1 } , q _ { 0 } = 0.5 ) .
We find an average SFR ( 2800Å ) /SFR ( H \alpha ) ratio of 3.2 using the Kennicutt ( 1998 ) SFR transformations .
This corresponds to the dust correction that is required to make the near UV data consistent with the reddening-corrected H \alpha data within the self-contained , I -selected CFRS sample .