A Comprehensive Study of Hα Emitters at z ∼ 0.62 in the DAWN Survey: The Need for Deep and Wide Regions (original) (raw)

The Astrophysical Journal

We present new estimates of the luminosity function (LF) and star formation rate density (SFRD) for an Hα selected sample at z ∼ 0.62 from the Deep And Wide Narrow-band (DAWN) survey. Our results are based on a new Hα sample in the extended COSMOS region (compared to Coughlin et al. 2018) with the inclusion of flanking fields, resulting in a total area coverage of ∼1.5 deg 2. A total of 241 Hα emitters were selected based on robust selection criteria using spectro-photometric redshifts and broadband color-color classification. Given that dust extinction is a dominant uncertainty in the estimation of LF and SFRD, we explore the effect of different dust correction prescriptions by calculating the LF and SFRD using a constant dust extinction correction, A Hα = 1 mag, a luminosity-dependent correction, and a stellar-mass dependent correction. The resulting Hα LFs are well fitted using Schechter functions with best-fit parameters: L * = 10 42.24 erg s −1 , φ * = 10 −2.85 Mpc −3 , α = −1.62 for constant dust correction, L * = 10 42.31 erg s −1 , φ * = 10 −2.8 Mpc −3 , α = −1.39 for luminosity-dependent dust correction, and L * = 10 42.36 erg s −1 , φ * = 10 −2.91 Mpc −3 , α = −1.48, for stellar mass-dependent dust correction. The deep and wide nature of the DAWN survey effectively samples Hα emitters over a wide range of luminosities, thereby providing better constraints on both the faint and bright end of the LF. Also, the SFRD estimates ρ SFR = 10 −1.39 M yr −1 Mpc −3 (constant dust correction), ρ SFR = 10 −1.47 M yr −1 Mpc −3 (luminosity-dependent dust correction), and ρ SFR = 10 −1.49 M yr −1 Mpc −3 (stellar mass-dependent dust correction) are in good agreement with the evolution of SFRD across redshifts (0 < z < 2) seen from previous Hα surveys.