The Halpha Luminosity Function and Star Formation Rate at z~0.24 Based on Subaru Deep Imaging Data

Abstract

We have carried out a deep imaging survey for H$\hat{I}\pm$ emitting galaxies at $z\approx$0.24 using a narrowband filter tuned with the redshifted line. The total sky area covered is 706 arcmin${}^2$ within a redshift range from 0.234 to 0.252 ($\hat{I}´z$=0.018). This corresponds to a volume of 3.9$\times 10^3$ Mpc${}^3$ when $\hat{I}{\text{c◯}}_{\mathrm{matter}}=0.3$, $\hat{I}{\text{c◯}}_{\hat{I}}›=0.7$, and $H_0$=70 km s${}^{-1}$ Mpc${}^{-1}$ are adopted. We obtain a sample of 348 H$\hat{I}\pm$ emitting galaxies whose observed emission-line equivalent widths are greater than 12 à . We find an extinction-corrected H$\hat{I}\pm$ luminosity density of $10^{39.65_{-0.12}^{+0.08}}$ ergs s${}^{-1}$ Mpc${}^{-3}$. Using the Kennicutt relation between the H$\hat{I}\pm$ luminosity and star formation rate, the star formation rate density in the covered volume is estimated as $0.036_{-0.012}^{+0.006}$ $M_{\sun}$ yr${}^{-1}$ Mpc${}^{-3}$. This value is higher by a factor of 3 than the local SFR density.

6 pages, 5 figures. ApJ Letters, in press