The hetdex pilot survey. IV. the evolution of [O II] emitting galaxies from z ∼ 0.5 to z ∼ 0

Robin Ciardullo, Caryl Gronwall, Joshua J. Adams, Guillermo A. Blanc, Karl Gebhardt, Steven L. Finkelstein, Shardha Jogee, Gary J. Hill, Niv Drory, Ulrich Hopp, Donald P. Schneider, Gregory R. Zeimann, Gavin B. Dalton

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


We present an analysis of the luminosities and equivalent widths of the 284 z < 0.56 [O II]-emitting galaxies found in the 169 arcmin2 pilot survey for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). By combining emission-line fluxes obtained from the Mitchell spectrograph on the McDonald 2.7 m telescope with deep broadband photometry from archival data, we derive each galaxy's dereddened [O II] λ3727 luminosity and calculate its total star formation rate. We show that over the last ∼5 Gyr of cosmic time, there has been substantial evolution in the [O II] emission-line luminosity function, with L* decreasing by ∼0.6 ± 0.2 dex in the observed function, and by ∼0.9 ± 0.2 dex in the dereddened relation. Accompanying this decline is a significant shift in the distribution of [O II] equivalent widths, with the fraction of high equivalent-width emitters declining dramatically with time. Overall, the data imply that the relative intensity of star formation within galaxies has decreased over the past ∼5 Gyr, and that the star formation rate density of the universe has declined by a factor of ∼2.5 between z ∼ 0.5 and z ∼ 0. These observations represent the first [O II]-based star formation rate density measurements in this redshift range, and foreshadow the advancements which will be generated by the main HETDEX survey.

Original languageEnglish (US)
Article number83
JournalAstrophysical Journal
Issue number1
StatePublished - May 20 2013

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'The hetdex pilot survey. IV. the evolution of [O II] emitting galaxies from z ∼ 0.5 to z ∼ 0'. Together they form a unique fingerprint.

Cite this