| Autor: |
CIARDULLO, ROBIN, GRONWALL, CARYL, ADAMS, JOSHUA J., BLANC, GUILLERMO A., GEBHARDT, KARL, FINKELSTEIN, STEVEN L., JOGEE, SHARDHA, HILL, GARY J., DRORY, NIV, HOPP, ULRICH, SCHNEIDER, DONALD P., ZEIMANN, GREGORY R., DALTON, GAVIN B. |
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| Zdroj: |
Astrophysical Journal; 5/20/2013, Vol. 769 Issue 1, p1-11, 11p |
| Abstrakt: |
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 ∼5Gyr 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 [Oii] 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 ∼5Gyr, 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. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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