The [O II] λ3727 Luminosity Function at z ~ 1
Abstract
We measure the evolution of the [O II] λ3727 luminosity function (LF) at 0.75 < z < 1.45 using high-resolution spectroscopy of ~14,000 galaxies observed by the Deep Extragalactic Evolutionary Probe 2 galaxy redshift survey. We find that brighter than L_[O II]=10^{42} erg s^{-1} the LF is well represented by a power law dN/dL vprop L α with slope α ~ -3. The number density of [O II]-emitting galaxies above this luminosity declines by a factor of gsim2.5 between z ~ 1.35 and z ~ 0.84. In the limit of no number-density evolution, the characteristic [O II] luminosity, L_[O II]^{*}, defined as the luminosity where the space density equals 10-3.5 dex-1 Mpc-3, declines by a factor of ~1.8 over the same redshift interval. Assuming that L_[O II] is proportional to the star formation rate (SFR), and negligible change in the typical dust attenuation in galaxies at fixed [O II] luminosity, the measured decline in L_[O II]{*} implies a ~25% per Gyr decrease in the amount of star ormation in galaxies during this epoch. Adopting a faint-end power-law slope of -1.3 ± 0.2, we derive the comoving SFR density in four redshift bins centered around z ~ 1 by integrating the observed [O II] LF using a local, empirical calibration between L_[O II] and SFR, which statistically accounts for variations in dust attenuation and metallicity among galaxies. We find that our estimate of the SFR density at z ~ 1 is consistent with previous measurements based on a variety of independent SFR indicators.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2009
- DOI:
- 10.1088/0004-637X/701/1/86
- arXiv:
- arXiv:0811.3035
- Bibcode:
- 2009ApJ...701...86Z
- Keywords:
-
- galaxies: evolution;
- galaxies: luminosity function;
- mass function;
- stars: formation;
- Astrophysics
- E-Print:
- 10 pages, 6 figures, 2 tables, resubmitted to ApJ, in emulateapj style. Comparison with narrow-band observations added. Wavelength coverage included into complete function, little effects. The data is available on http://bias.cosmo.fas.nyu.edu/galevolution/