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Spatially resolved dust emission of extremely metal-poor galaxies

Zhou, Luwenjia and Shi, Yong and Diaz-Santos, Taino and Armus, Lee and Helou, George and Stierwalt, Sabrina and Li, Aigen (2016) Spatially resolved dust emission of extremely metal-poor galaxies. Monthly Notices of the Royal Astronomical Society, 458 (1). pp. 772-780. ISSN 0035-8711. http://resolver.caltech.edu/CaltechAUTHORS:20160603-084605717

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Abstract

We present infrared (IR) spectral energy distributions (SEDs) of individual star-forming regions in four extremely metal-poor (EMP) galaxies with metallicity Z ≲ Z_⊙/10 as observed by the Herschel Space Observatory. With the good wavelength coverage of the SED, it is found that these EMP star-forming regions show distinct SED shapes as compared to those of grand design Spirals and higher metallicity dwarfs: they have on average much higher f_(70μm)/f_(160 μm) ratios at a given f_(160 μm)/f_(250 μm) ratio; single modified blackbody (MBB) fittings to the SED at λ ≥ 100 μm still reveal higher dust temperatures and lower emissivity indices compared to that of Spirals, while two MBB fittings to the full SED with a fixed emissivity index (β = 2) show that even at 100 μm, about half of the emission comes from warm (50 K) dust, in contrast to the cold (∼20 K) dust component. Our spatially resolved images furthermore reveal that the far-IR colours including f_(70 μm)/f_(160 μm), f_(160 μm)/f_(250 μm) and f_(250 μm)/f_(350 μm) are all related to the surface densities of young stars as traced by far-UV, 24 μm and star formation rates (SFRs), but not to the stellar mass surface densities. This suggests that the dust emitting at wavelengths from 70 to 350 μm is primarily heated by radiation from young stars.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1093/mnras/stw345DOIArticle
http://mnras.oxfordjournals.org/content/458/1/772.abstractPublisherArticle
http://arxiv.org/abs/1602.05362arXivDiscussion Paper
ORCID:
AuthorORCID
Diaz-Santos, Taino0000-0003-0699-6083
Additional Information:© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 February 10. Received 2016 February 10. In original form 2015 November 19. First published online March 1, 2016. We thank the anonymous referee for helpful suggestions that improved the quality of the paper. LZ and YS acknowledge support for this work from the National Natural Science Foundation of China (grant 11373021), the Strategic Priority Research Program ‘The Emergence of Cosmological Structures’ of the Chinese Academy of Sciences (grant No. XDB09000000), and Excellent Youth Foundation of Jiangsu Scientific Committee (grant BK20150014). LZ also thanks for the support by the National Natural Science Foundation of China (Grant No. J1210039). AL is supported in part by NSF AST-1311804 and NASA NNX14AF68G. This research has made extensive use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This work is based (in part) on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.’ The Galaxy Evolution Explorer (GALEX) is a NASA Small Explorer, launched in 2003 April. We acknowledge NASA's support for construction, operation, and science analysis for the GALEX mission.
Group:Infrared Processing and Analysis Center (IPAC)
Funders:
Funding AgencyGrant Number
National Natural Science Foundation of China11373021
Chinese Academy of SciencesXDB09000000
Jiangsu Scientific Committee Excellent Youth Foundation BK20150014
National Natural Science Foundation of ChinaJ1210039
NSFAST-1311804
NASANNX14AF68G
NASA/JPL/CaltechUNSPECIFIED
Subject Keywords:galaxies: dwarf galaxies: ISM
Record Number:CaltechAUTHORS:20160603-084605717
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160603-084605717
Official Citation:Luwenjia Zhou, Yong Shi, Taino Diaz-Santos, Lee Armus, George Helou, Sabrina Stierwalt, and Aigen Li Spatially resolved dust emission of extremely metal-poor galaxies MNRAS (May 01, 2016) Vol. 458 772-780 doi:10.1093/mnras/stw345 first published online March 1, 2016
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:67640
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:03 Jun 2016 16:22
Last Modified:24 Oct 2017 22:30

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