Studying the ISM at ∼ 10 pc scale in NGC 7793 with MUSE II. Constraints on the oxygen abundance and ionising radiation escape (Corrigendum)

1 Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, 106 91 Stockholm, Sweden e-mail: lorenza.dellabruna@astro.su.se 2 Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA, USA 3 European Space Agency (ESA), ESA Office, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 4 Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2612, Australia 5 Observatoire de Genève, Université de Genève, Chemin Pegasi 51, 1290 Versoix, Switzerland 6 Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano Bicocca, Piazza della Scienza 3, 20126 Milano, Italy 7 Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE, UK 8 Centre for Extragalactic Astronomy, Durham University, South Road, Durham DH1 3LE, UK 9 Department of Astronomy, New Mexico State University, Las Cruces, NM 88001, USA 10 Universidad Nacional Autónoma de México, Instituto de Astronomía, AP 106, Ensenada 22800, BC, México

in the original paper reports inaccurate values of Q 0 exp,YSC and Q 0 obs (and hence of the related quantities Q exp,tot , Q exptot /Q obs , and f esc ). The error in Q 0 exp,YSC results from a mistake in the sampling of the cluster probability distribution functions (PDFs), whereas Q 0 obs was mistakenly computed from non-dereddened values of L(Hα). In Table 1 we provide a revised version of the original Table 3, and in Figs. 1 and 2 we show revised versions of the original Figs. 10 and 11.
The revised values do not change any of the conclusions stated in the original paper. In the following we provide revised text for the affected sections.

Resulting budget
We observe that in regions 2, 3, 6, and 7, the value of f esc (with the related uncertainty) reaches unphysical values f esc < 0, indicating that either the models are underestimating the photon flux, or the observed luminosity is being overestimated. This is possibly due to the reddening correction or to the exact location of the region boundaries.
Overall, we find f esc,H ii = 0.43 +0.13 −0.23 for the entire population of H ii regions. We observe that the stellar population in the diffuse ionised gas (DIG) produces a more than sufficient amount of ionising photons (Q(H 0 ) exp > Q(H 0 ) obs ), and that the DIG is therefore consistent with being selfionised, with f esc,DIG = 0.85 +0.04 −0.07 . This holds also if considering a maximum mass of 30 M for field O stars, in which case we find f esc,DIG = 0.50 +0.12 −0.20 . Our conclusion therefore remains unchanged: in our field of view (FoV), we observe that the sources of ionising photons produce a photon flux that is more than sufficient to explain the emission of the ionised interstellar medium (ISM), both within and outside the H ii regions.  Notes. The uncertainties on log Q 0 obs are all of the order of ≤0.001.

Discussion
Our revised estimate of the fraction of diffuse gas expected is This is in even closer agreement with Paper I. The revised Q(H 0 ) values still point to a DIG consistent with being self-ionised by field stars and clusters, with an overabundance of ionising photons f esc ∼ 0.85 +0.04 −0.07 ; we confirm this trend also when considering our lower-limit estimate.
Overall the H ii regions are leaking ionising photons at a rate f esc ∼ 0.43 +0.13 −0.23 , with five out of eight having an f esc 0.3. Even when considering the uncertainties, we find f vesc > 0 for the DIG overall and for four out of the eight H ii regions inspected.

Conclusions
Overall, we find an escape fraction f esc = 0.43 +0.13 −0.23 for the population of H ii regions, and that the DIG in our FoV is more than consistent with being self-ionised, with an f esc = 0.85 +0.04 −0.07 . This holds even when considering a lower-limit estimate for the DIG flux, which was derived by assuming a maximum mass of 30 M for the field O stars. We furthermore find that the f DIG,exp 0.15 obtained by modelling the DIG stellar population is in good agreement with the DIG fraction derived from the observed Hα luminosity in Paper I, f DIG,obs = 0.15. Finally, we observe an f esc 0.3 in five out of the eight studied regions.