We are grateful for the enlightening discussions and valuable comments on this work by an anonymous referee that improved the scientific outcome and quality of the paper. The authors appreciate the useful discussions and suggestions on this work by J. Chisholm, N. V. Asari, G. Stasinska, C. Morisset, and I. Perez. KG is supported by the Australian Research Council through the Discovery Early Career Researcher Award (DECRA) Fellowship (project number DE220100766) funded by the Australian Government. Parts of this work are supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in three Dimensions (ASTRO 3D), through project number CE170100013. MRK acknowledges support from the Australian Research Council through its Future Fellowship funding scheme, award FT180100375. MM acknowledges the support of the Swedish Research Council, Vetenskapsradet (grant 2019-00502). RSK is thankful for financial support from the European Research Council in the ERC Synergy Grant ECOGAL' (project ID 855130), from the German Science Foundation (DFG) via the Collaborative Research Center The Milky Way System' (SFB 881, Funding-ID 138713538, subprojects A1, B1, B2, and B8), and from the Heidelberg Cluster of Excellence STRUCTURES' (EXC 2181-390900948). RSK and JWT also acknowledge funding from the German Space Agency (DLR) and the Federal Ministry for Economic Affairs and Climate Action (BMWK) in project MAINN' (grant number 50OO2206). The group in Heidelberg also thanks for computing resources provided by the Ministry of Science, Research and the Arts (MWK) of the State of Baden-Wuerttemberg through bwHPC and DFG through grant INST 35/1134-1. FUGG and for data storage at SDS@hd through grant INST 35/1314-1 FUGG. MF is thankful for financial support from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement number 757535) and by Fondazione Cariplo (grant number 2018-2329). LC acknowledges financial support from ANID/Fondecyt Regular project 1210992. JW acknowledges support by the NSFC grants U1831205 and 12033004. This research is based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, under NASA Contract NAS 5-26555. These observations are associated with Program 13364. Support for Program 13364 was provided by NASA through a grant from the Space Telescope Science Institute. The SIGNALS observations were obtained with SITELLE, a joint project between Universite Laval, ABB-Bomem, Universit e de Montreal, and the CFHT, with funding support from the Canada Foundation for Innovation (CFI), the National Sciences and Engineering Research Council of Canada (NSERC), Fonds de Recherche du Quebec - Nature et Technologies (FRQNT), and CFHT. The authors wish to recognize and acknowledge the very significant cultural role that the summit of Maunakea has always had within the indigenous Hawaiian community. The authors are most grateful to have the opportunity to conduct observations from this mountain with the CFHT. This work made use of Astropy:6 a community-developed core Python package and an ecosystem of tools and resources for astronomy (Astropy Collaboration et.al. 2013, 2018, 2022). This research has also made use of Matplotlib (Hunter 2007), NumPy (Harris et.al. 2020), and NASA's Astrophysics Data System (ADS) Bibliographic Services.7

The ionizing radiation of young and massive stars is a crucial form of stellar feedback. Most ionizing (Lyman-continuum; LyC, λ < 912Å) photons are absorbed close to the stars that produce them, forming compact H ii regions, but some escape into the wider galaxy. Quantifying the fraction of LyC photons that escape is an open problem. In this work, we present a seminovel method to estimate the escape fraction by combining broadband photometry of star clusters from the Legacy ExtraGalactic UV Survey (LEGUS) with H ii regions observed by the Star formation, Ionized gas, and Nebular Abundances Legacy Survey (SIGNALS) in the nearby spiral galaxy NGC 628. We first assess the completeness of the combined catalogue, and find that 49 per cent of H ii regions lack corresponding star clusters as a result of a difference in the sensitivities of the LEGUS and SIGNALS surveys. For H ii regions that do have matching clusters, we infer the escape fraction from the difference between the ionizing power required to produce the observed H ii luminosity and the predicted ionizing photon output of their host star clusters; the latter is computed using a combination of LEGUS photometric observations and a stochastic stellar population synthesis code slug (Stochastically Lighting Up Galaxies). Overall, we find an escape fraction of across our sample of 42 H ii regions; in particular, we find H ii regions with high fesc are predominantly regions with low -luminosity. We also report possible correlation between fesc and the emission lines and. © 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society

Full list of the authors: Teh, Jia Wei; Grasha, Kathryn; Krumholz, Mark R.; Battisti, Andrew J.; Calzetti, Daniela; Rousseau-Nepton, Laurie; Rhea, Carter; Adamo, Angela; Kennicutt, Robert C.; Grebel, Eva K.; Cook, David O.; Combes, Francoise; Messa, Matteo; Linden, Sean T.; Klessen, Ralf S.; Vilchez, José M.; Fumagalli, Michele; McLeod, Anna; Smith, Linda J.; Chemin, Laurent; Wang, Junfeng; Sabbi, Elena; Sacchi, Elena; Petric, Andreea; Della Bruna, Lorenza; Boselli, Alessandro