In:
The Astronomical Journal, American Astronomical Society, Vol. 164, No. 4 ( 2022-10-01), p. 159-
Abstract:
We investigate the effects of stellar populations and sizes on Ly α escape in 27 spectroscopically confirmed and 35 photometric Ly α emitters (LAEs) at z ≈ 2.65 in seven fields of the Boötes region of the NOAO Deep Wide-Field Survey. We use deep HST/WFC3 imaging to supplement ground-based observations and infer key galaxy properties. Compared to typical star-forming galaxies (SFGs) at similar redshifts, the LAEs are less massive ( M ⋆ ≈ 10 7 –10 9 M ⊙ ), younger (ages ≲1 Gyr), smaller ( r e 〈 1 kpc), and less dust-attenuated ( E ( B − V ) ≤ 0.26 mag) but have comparable star formation rates (SFRs ≈ 1–100 M ⊙ yr −1 ). Some of the LAEs in the sample may be very young galaxies having low nebular metallicities ( Z neb ≲ 0.2 Z ⊙ ) and/or high ionization parameters ( log ( U ) ≳ − 2.4 ). Motivated by previous studies, we examine the effects of the concentration of star formation and gravitational potential on Ly α escape by computing SFR surface density, Σ SFR , and specific SFR surface density, Σ sSFR . For a given Σ SFR , the Ly α escape fraction is higher for LAEs with lower stellar masses. The LAEs have a higher Σ sSFR , on average, compared to SFGs. Our results suggest that compact star formation in a low gravitational potential yields conditions amenable to the escape of Ly α photons. These results have important implications for the physics of Ly α radiative transfer and for the type of galaxies that may contribute significantly to cosmic reionization.
Type of Medium:
Online Resource
ISSN:
0004-6256
,
1538-3881
DOI:
10.3847/1538-3881/ac83a9
Language:
Unknown
Publisher:
American Astronomical Society
Publication Date:
2022
detail.hit.zdb_id:
2207625-6
detail.hit.zdb_id:
2003104-X
SSG:
16,12
