Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published November 2014 | Published + Submitted
Journal Article Open

High-resolution, 3D radiative transfer modeling I. The grand-design spiral galaxy M51

Abstract

Context. Dust reprocesses about half of the stellar radiation in galaxies. The thermal re-emission by dust of absorbed energy is considered to be driven merely by young stars so is often applied to tracing the star formation rate in galaxies. Recent studies have argued that the old stellar population might be responsible for a non-negligible fraction of the radiative dust heating. Aims. In this work, we aim to analyze the contribution of young (≲100 Myr) and old (~10 Gyr) stellar populations to radiative dust heating processes in the nearby grand-design spiral galaxy M 51 using radiative transfer modeling. High-resolution 3D radiative transfer (RT) models are required to describe the complex morphologies of asymmetric spiral arms and clumpy star-forming regions and to model the propagation of light through a dusty medium. Methods. In this paper, we present a new technique developed to model the radiative transfer effects in nearby face-on galaxies. We construct a high-resolution 3D radiative transfer model with the Monte-Carlo code SKIRT to account for the absorption, scattering, and non-local thermal equilibrium (NLTE) emission of dust in M 51. The 3D distribution of stars is derived from the 2D morphology observed in the IRAC 3.6 μm, GALEX FUV, Hα, and MIPS 24 μm wavebands, assuming an exponential vertical distribution with an appropriate scale height. The dust geometry is constrained through the far-ultraviolet (FUV) attenuation, which is derived from the observed total-infrared-to-far-ultraviolet luminosity ratio. The stellar luminosity, star formation rate, and dust mass have been scaled to reproduce the observed stellar spectral energy distribution (SED), FUV attenuation, and infrared SED. Results. The dust emission derived from RT calculations is consistent with far-infrared and submillimeter observations of M 51, implying that the absorbed stellar energy is balanced by the thermal re-emission of dust. The young stars provide 63% of the energy for heating the dust responsible for the total infrared emission (8−1000 μm), while 37% of the dust emission is governed through heating by the evolved stellar population. In individual wavebands, the contribution from young stars to the dust heating dominates at all infrared wavebands but gradually decreases towards longer infrared and submillimeter wavebands for which the old stellar population becomes a non-negligible source of heating. Upon extrapolation of the results for M 51, we present prescriptions for estimating the contribution of young stars to the global dust heating based on a tight correlation between the dust heating fraction and specific star formation rate.

Additional Information

© 2014 ESO. Article published by EDP Sciences. Received 4 August 2014. Accepted 11 September 2014. Published online 10 November 2014. We thank the referee for useful comments and suggestions. We thank Richard Tuffs, Cristina Popescu, Simone Bianchi, Manolis Xilouris, and Giovanni Natale for fruitful discussions on the analysis of the dust heating fractions and the clumpiness of dust. We thank Robert C. Kennicutt Jr. for useful suggestions. We also thank Brent Groves for kindly providing us the dust masses associated with the emission spectra of the young Hii regions with surrounding PDR envelopes. IDL is a postdoctoral researcher of the FWO-Vlaanderen (Belgium). M.B., J.F. and T.H. acknowledge the financial support of the Belgian Science Policy Office (BELSPO) through the PRODEX project "Herschel-PACS Guaranteed Time and Open Time Programs: Science Exploitation" (C90370). P.C. acknowledges the financial support of the Belgian Science Policy Office (BELSPO) through the CHARM framework (Contemporary physical challenges in Heliospheric and AstRophysical Models), a phase VII Interuniversity Attraction Pole (IAP) program. L.C. acknowledges support under the Australian Research Council's Discovery Projects funding scheme (project number 130100664). PACS has been developed by a consortium of institutes led by MPE (Germany) and including UVIE (Austria); KU Leuven, CSL, IMEC (Belgium); CEA, LAM (France); MPIA (Germany); INAFIFSI/ OAA/OAP/OAT, LENS, SISSA (Italy); IAC (Spain). This development has been supported by the funding agencies BMVIT (Austria), ESA-PRODEX (Belgium), CEA/CNES (France), DLR (Germany), ASI/INAF (Italy), and CICYT/ MCYT (Spain). SPIRE has been developed by a consortium of institutes led by Cardiff University (UK) and including Univ. Lethbridge (Canada); NAOC (China); CEA, LAM (France); IFSI, Univ. Padua (Italy); IAC (Spain); Stockholm Observatory (Sweden); Imperial College London, RAL, UCL-MSSL, UKATC, Univ. Sussex (UK); and Caltech, JPL, NHSC, Univ. Colorado (USA). This development has been supported by national funding agencies: CSA (Canada); NAOC (China); CEA, CNES, CNRS (France); ASI (Italy); MCINN (Spain); SNSB (Sweden); STFC and UKSA (UK); and NASA (USA).

Attached Files

Published - aa24747-14.pdf

Submitted - 1409.3857v1.pdf

Files

aa24747-14.pdf
Files (6.3 MB)
Name Size Download all
md5:feb15679a83659575dece3c5cc039224
3.1 MB Preview Download
md5:02ae91da4d87aced99c3e2e9b0263014
3.2 MB Preview Download

Additional details

Created:
August 22, 2023
Modified:
October 20, 2023