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

• Published in: The Astrophysical journal Vol. 892; no. 1; p. 30
• Main Authors: Harish, Santosh, Coughlin, Alicia, Rhoads, James E., Malhotra, Sangeeta, Finkelstein, Steven L., Stevans, Matthew, Tilvi, Vithal S., Khostovan, Ali Ahmad, Veilleux, Sylvain, Wang, Junxian, Hibon, Pascale, Zabl, Johnnes, Joshi, Bhavin, Pharo, John, Wold, Isak, Perez, Lucia A., Zheng, Zhen-Ya, Probst, Ronald, Swaters, Rob, Mobasher, Bahram, Jiang, Tianxing, Yang, Huan
• Format: Journal Article
• Language: English
• Published: Philadelphia IOP Publishing 20-03-2020; American Astronomical Society
• Subjects: Astrophysics; Broadband; Color; Dust; Emitters; Extinction; Luminosity; Mathematical analysis; Polls & surveys; Sciences of the Universe; Spectrophotometry; Star & galaxy formation; Star formation; Star formation rate; Stellar evolution; 1569; Star forming regions; Astrophysics - Astrophysics of Galaxies; Star formation; 1565; 942; 459; Emission line galaxies; Luminosity function
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ab7015

Abstract
We present new estimates of the luminosity function (LF) and star formation rate density (SFRD) for an H
α
-selected sample at
z
 ∼ 0.62 from the Deep And Wide Narrow-band (DAWN) survey. Our results are based on a new H
α
sample in the extended COSMOS region (compared to Coughlin et al.) with the inclusion of flanking fields, resulting in a total area coverage of ∼1.5 deg
2
. A total of 241 H
α
emitters were selected based on robust selection criteria using spectrophotometric 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
H
α
 = 1 mag, a luminosity-dependent correction, and a stellar-mass-dependent correction. The resulting H
α
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
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 H
α
emitters over a wide range of luminosities, thereby providing better constraints on both the faint and bright ends 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
−1.46
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 H
α
surveys.