High-resolution radiative transfer modelling of M33 Williams, Thomas G. Relaño Pastor, Mónica Radiative transfer Dust, extinction Galaxies: individual:M33 Galaxies: ISM Galaxies: star formation The authors thank the anonymous reviewer, whose comments have certainly improved the manuscript. The authors also thank Peter Camps for valuable technical advice, along with all of the participants at the recent SKIRT meeting for comments and discussions. I.D.L. gratefully acknowledges the supports of the Research Foundation – Flanders (FWO). M.W.L.S acknowledges funding from the UK Science and Technology Facilities Council consolidated grant ST/K000926/1. M.R. acknowledges support by the research projects AYA2014-53506-P and AYA2017-84897P from the Spanish Ministerio de Econom´ıa y Competitividad. This research made use of MONTAGE (http://montage.ipac.caltech.edu/), which is funded by the National Science Foundation under Grant Number ACI-1440620, and was previously funded by the National Aeronautics and Space Administration’s Earth Science Technology Office, Computation Technologies Project, under Cooperative Agreement Number NCC5-626 between NASA and the California Institute of Technology. This research has made use of Astropy, a community-developed core PYTHON package for Astronomy (http: //www.astropy.org/; Astropy Collaboration et al. 2013, 2018). This research has made use of NumPy (http://www.numpy.org/; van der Walt, Colbert & Varoquaux 2011), SciPy (http://www.scipy.org/), andMatPlotLib (http://matplotlib.org/; Hunter 2007). This research made use of APLpy, an open-source plotting package for PYTHON (https://aplpy.github.io/; Robitaille & Bressert 2012). In this work, we characterize the contributions from both ongoing star formation and the ambient radiation field in Local Group galaxy M33, as well as estimate the scale of the local dust-energy balance (i.e. the scale at which the dust is re-emitting starlight generated in that same region) in this galaxy through high-resolution radiative transfer (RT) modelling, with defined stellar and dust geometries. We have characterized the spectral energy distribution (SED) of M33 from UV to sub-mm wavelengths, at a spatial scale of 100 pc. We constructed input maps of the various stellar and dust geometries for use in the RTmodelling. By modifying our dust mix (fewer very small carbon grains and a lower silicate-to-carbon ratio as compared to the Milky Way), we can much better fit the sub-mm dust continuum. Using this new dust composition, we find that we are able to well reproduce the observed SED of M33 using our adopted model. In terms of stellar attenuation by dust, we find a reasonably strong, broad UV bump, as well as significant systematic differences in the amount of dust attenuation when compared to standard SED modelling.We also find discrepancies in the residuals of the spiral arms versus the diffuse interstellar medium (ISM), indicating a difference in properties between these two regimes. The dust emission is dominated by heating due to the young stellar populations at all wavelengths (∼80 per cent at 10 μm to ∼50 per cent at 1 mm). We find that the local dust-energy balance is restored at spatial scales greater than around 1.5 kpc. 2020-03-27T13:08:31Z 2020-03-27T13:08:31Z 2019-05-24 info:eu-repo/semantics/article Thomas G Williams, Maarten Baes, Ilse De Looze, Monica Relaño, Matthew W L Smith, Sam Verstocken, Sébastien Viaene, High-resolution radiative transfer modelling of M33, Monthly Notices of the Royal Astronomical Society, Volume 487, Issue 2, August 2019, Pages 2753–2770, [https://doi.org/10.1093/mnras/stz1441] http://hdl.handle.net/10481/60748 10.1093/mnras/stz1441 eng http://creativecommons.org/licenses/by-nc-nd/3.0/es/ info:eu-repo/semantics/openAccess Atribución-NoComercial-SinDerivadas 3.0 España Oxford University Press