The stellar population of a z ∼ 3.25 Lyα-emitting group associated with a damped Lyα absorber

Pruto, Giulia; Fumagalli, Michele; Rafelski, Marc; Revalski, Mitchell; Fossati, Matteo; Mackenzie, Ruari; Theuns, Tom

doi:10.1051/0004-6361/202450609

The stellar population of a z ∼ 3.25 Lyα-emitting group associated with a damped Lyα absorber

Pruto, Giulia; Fumagalli, Michele; Rafelski, Marc; Revalski, Mitchell; Fossati, Matteo; Mackenzie, Ruari; Theuns, Tom

Authors

Giulia Pruto

Michele Fumagalli

Marc Rafelski

Mitchell Revalski

Matteo Fossati

Ruari Mackenzie

Professor Tom Theuns tom.theuns@durham.ac.uk
Professor

Abstract

We present near-infrared observations, acquired with the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope (HST), of a Lyα-emitting double-clumped nebula at z ≈ 3.25 associated with a damped Lyα absorber (DLA). With the WFC3/F160W data we observe the stellar continuum around 3600 Å in the rest frame of a galaxy embedded in the west clump of the nebula, GW, for which we estimate a star formation rate (SFR) of SFRGW = 5.0 ± 0.4 M⊙ yr−1 and a maximum stellar mass MGW < 9.9 ± 0.7 × 109 M⊙. With the enhanced spatial resolution of HST, we discover the presence of an additional faint source, GE, in the center of the east clump, with SFRGE = 0.70 ± 0.20 M⊙ yr−1 and a maximum stellar mass MGE < 1.4 ± 0.4 × 109 M⊙. We show that the Lyα emission in the two clumps can be explained by recombination following in situ photoionization by the two galaxies, assuming escape fractions of ionizing photons of ≲0.24 for GW and ≲0.34 for GE. The fact that GW is offset by ≈8 kpc from the west clump means we cannot fully rule out the presence of additional fainter star-forming sources, which would further contribute to the photon budget inside this ≈1012 M⊙ galaxy group that extends over a region of 30 × 50 kpc.

Citation

Pruto, G., Fumagalli, M., Rafelski, M., Revalski, M., Fossati, M., Mackenzie, R., & Theuns, T. (2024). The stellar population of a z ∼ 3.25 Lyα-emitting group associated with a damped Lyα absorber. Astronomy & Astrophysics, 691, Article A222. https://doi.org/10.1051/0004-6361/202450609

Journal Article Type	Article
Acceptance Date	Sep 16, 2024
Online Publication Date	Nov 15, 2024
Publication Date	2024-11
Deposit Date	Jan 15, 2025
Publicly Available Date	Jan 15, 2025
Journal	Astronomy & Astrophysics
Print ISSN	0004-6361
Electronic ISSN	1432-0746
Publisher	EDP Sciences
Peer Reviewed	Peer Reviewed
Volume	691
Article Number	A222
DOI	https://doi.org/10.1051/0004-6361/202450609
Public URL	https://durham-repository.worktribe.com/output/3335682

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Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.