University of Oulu

Aaron E. Watkins et al 2017 ApJ 851 51.

Star-forming environments throughout the M101 Group

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Author: Watkins, Aaron E.1,2; Mihos, J. Christopher1; Harding, Paul1
Organizations: 1Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106, USA
2Astronomy Research Unit, University of Oulu, FI-90014, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.1 MB)
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Language: English
Published: IOP Publishing, 2017
Publish Date: 2018-06-13


We present a multiwavelength study of star formation within the nearby M101 Group, including new deep Hα imaging of M101 and its two companions. We perform a statistical analysis of the Hα-to-FUV flux ratios in H ii regions located in three different environments: M101’s inner disk, M101’s outer disk, and M101’s lower-mass companion galaxy NGC 5474. We find that, once bulk radial trends in extinction are taken into account, both the median and scatter in F /F FUV in H ii regions are invariant across all of these environments. Also, using Starburst99 models, we are able to qualitatively reproduce the distributions of F /F FUV throughout these different environments using a standard Kroupa initial mass function (IMF); hence, we find no need to invoke truncations in the upper-mass end of the IMF to explain the young star-forming regions in the M101 Group even at extremely low surface density. This implies that star formation in low-density environments differs from star formation in high-density environments only by intensity and not by cloud-to-cloud physics.

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Series: Astrophysical journal
ISSN: 0004-637X
ISSN-E: 1538-4357
ISSN-L: 0004-637X
Volume: 851
Issue: 1
Article number: 51
DOI: 10.3847/1538-4357/aa8fcd
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: This work has been supported by the National Science Foundation through award 1108964 to JCM, as well as through award 1211144 to PH.
Copyright information: © 2017. The American Astronomical Society. All rights reserved. Published in this repository with the kind permission of the publisher.