MIDIS: JWST NIRCam and MIRI Unveil the Stellar Population Properties of Lyα Emitters and Lyman-break Galaxies at z ≃ 3–7
Abstract
We study the stellar population properties of 182 spectroscopically confirmed (MUSE/VLT) Lyα emitters (LAEs) and 450 photometrically selected Lyman-break galaxies (LBGs) at z = 2.8–6.7 in the Hubble Extreme Deep Field. Leveraging the combined power of Hubble Space Telescope and JWST NIRCam and MIRI observations, we analyze their rest-frame UV-through-near-IR spectral energy distributions, with MIRI playing a crucial role in robustly assessing the LAEs' stellar masses and ages. Our LAEs are low-mass objects $({{\rm{log}}}_{10}({M}_{\star }/{M}_{\odot })\simeq 7.5)$ with little or no dust extinction (E(B ‑ V) ≃ 0.1) and a blue UV continuum slope (β ≃ ‑2.2). While 75% of our LAEs are young (<100 Myr), the remaining 25% have significantly older stellar populations (≥100 Myr). These old LAEs are statistically more massive, less extinct, and have lower specific star formation rate than young LAEs. Besides, they populate the plane of M ⋆ versus star formation rate along the main sequence of star-forming galaxies, while young LAEs populate the starburst region. The comparison between the LAEs' properties and those of a stellar-mass-matched sample of LBGs shows no statistical difference between these objects, except for the LBGs' redder UV continuum slope and marginally larger E(B ‑ V) values. Interestingly, 48% of the LBGs have ages <10 Myr and are classified as starbursts, but lack detectable Lyα emission. This is likely due to H I resonant scattering and/or dust-selective extinction. Overall, we find that JWST observations are crucial in determining the properties of LAEs and shedding light on their comparison with LBGs.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2024
- DOI:
- 10.3847/1538-4357/ad15f6
- arXiv:
- arXiv:2309.08515
- Bibcode:
- 2024ApJ...963...97I
- Keywords:
-
- Lyman-alpha galaxies;
- Lyman-break galaxies;
- Galaxy evolution;
- Infrared telescopes;
- 978;
- 979;
- 594;
- 794;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 22 pages, 15 figures, 5 tables. Accepted for publication in APJ