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 March 21, 2015 | Published + Submitted
Journal Article Open

The relationship between polycyclic aromatic hydrocarbon emission and far-infrared dust emission from NGC 2403 and M83

Abstract

We examine the relation between polycyclic aromatic hydrocarbon (PAH) emission at 8 μm and far-infrared emission from hot dust grains at 24 μm and from large dust grains at 160 and 250 μm in the nearby spiral galaxies NGC 2403 and M83 using data from the Spitzer Space Telescope and Herschel Space Observatory. We find that the PAH emission in NGC 2403 is better correlated with emission at 250 μm from dust heated by the diffuse interstellar radiation field (ISRF) and that the 8/250-μm surface brightness ratio is well correlated with the stellar surface brightness as measured at 3.6 μm. This implies that the PAHs in NGC 2403 are intermixed with cold large dust grains in the diffuse interstellar medium (ISM) and that the PAHs are excited by the diffuse ISRF. In M83, the PAH emission appears more strongly correlated with 160 μm emission originating from large dust grains heated by star-forming regions. However, the PAH emission in M83 is low where the 24-μm emission peaks within star-forming regions, and enhancements in the 8/160-μm surface brightness ratios appear offset relative to the dust and the star-forming regions within the spiral arms. This suggests that the PAHs observed in the 8 μm band are not excited locally within star-forming regions but either by light escaping non-axisymmetrically from star-forming regions or locally by young, non-photoionizing stars that have migrated downstream from the spiral density waves. The results from just these two galaxies show that PAHs may be excited by different stellar populations in different spiral galaxies.

Additional Information

© 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 December 17. Received 2014 November 13; in original form 2014 June 2. First published online February 2, 2015. This work has been produced as part of an MSc thesis for the University of Manchester. SPIRE has been developed by a consortium of institutes led by Cardiff University (UK) and including: University Lethbridge (Canada); NAOC (China); CEA, LAM (France); IFSI, Univ. Padua (Italy); IAC (Spain); Stockholm Observatory (Sweden); Imperial College London, RAL, UCL-MSSL, UKATC, University 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, UKSA (UK); and NASA (USA). IDL is a postdoctoral researcher of the FWO-Vlaanderen (Belgium).

Attached Files

Published - MNRAS-2015-Jones-168-87.pdf

Submitted - 1412.7344v1.pdf

Files

MNRAS-2015-Jones-168-87.pdf
Files (7.9 MB)
Name Size Download all
md5:bddefda9d52ad1bb8f5d6e06b0bcc874
5.2 MB Preview Download
md5:f9788ce46bba9aff5aaa616bf139e902
2.7 MB Preview Download

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023