Deciphering stellar metallicities in the early Universe: case study of a young galaxy at z = 4.77 in the MUSE eXtremely Deep Field

Author:

Matthee Jorryt,Feltre Anna,Maseda Michael,Nanayakkara Themiya,Boogaard Leindert,Bacon Roland,Verhamme Anne,Leclercq Floriane,Kusakabe Haruka,Urrutia Tanya,Wisotzki Lutz

Abstract

Directly characterising the first generations of stars in distant galaxies is a key quest of observational cosmology. We present a case study of ID53 at z = 4.77, the UV-brightest (but L) star-forming galaxy at z > 3 in the MUSE eXtremely Deep Field with a mass of ≈109 M. In addition to very strong Lyman-α (Lyα) emission, we clearly detect the (stellar) continuum and an N V P Cygni feature, interstellar absorption, fine-structure emission and nebular C IV emission lines in the 140 h spectrum. Continuum emission from two spatially resolved components in Hubble Space Telescope data are blended in the MUSE data, but we show that the nebular C IV emission originates from a subcomponent of the galaxy. The UV spectrum can be fit with recent BPASS stellar population models combined with single-burst or continuous star formation histories (SFHs), a standard initial mass function, and an attenuation law. Models with a young age and low metallicity (log10(age/yr) = 6.5–7.6 and [Z/H] = −2.15 to −1.15) are preferred, but the details depend on the assumed SFH. The intrinsic Hα luminosity of the best-fit models is an order of magnitude higher than the Hα luminosity inferred from Spitzer/IRAC data, which either suggests a high escape fraction of ionising photons, a high relative attenuation of nebular to stellar dust, or a complex SFH. The metallicity appears lower than the metallicity in more massive galaxies at z = 3 − 5, consistent with the scenario according to which younger galaxies have lower metallicities. This chemical immaturity likely facilitates Lyα escape, explaining why the Lyα equivalent width is anti-correlated with stellar metallicity. Finally, we stress that uncertainties in SFHs impose a challenge for future inferences of the stellar metallicity of young galaxies. This highlights the need for joint (spatially resolved) analyses of stellar spectra and photo-ionisation models.

Publisher

EDP Sciences

Subject

Space and Planetary Science,Astronomy and Astrophysics

Reference159 articles.

1. Galaxies and Intergalactic Matter at Redshiftz ∼ 3: Overview

2. The Chemical Composition of the Sun

3. On the detectability of Lyα emission in star forming galaxies

4. Energy spectra of X-ray clusters of galaxies

5. Bacon R., Accardo M., Adjali L., et al. 2010, in Ground-based and Airborne Instrumentation for Astronomy III, Proc. SPIE, 7735, 773508

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