Extinction Maps and Dust-to-gas Ratios in Nearby Galaxies with LEGUS

Kahre, L; Walterbos, RA; Kim, H; Thilker, D; Calzetti, D; Lee, JC; Sabbi, E; Ubeda, L; Aloisi, A; Cignoni, M; Cook, DO; Dale, DA; Elmegreen, BG; Elmegreen, DM; Fumagalli, M; Gallagher, JS; Gouliermis, DA; Grasha, K; Grebel, EK; Hunter, DA; Sacchi, E; Smith, LJ; Tosi, M; Adamo, A; Andrews, JE; Ashworth, G; Bright, SN; Brown, TM; Chandar, R; Christian, C; De Mink, SE; Dobbs, C; Evans, AS; Herrero, A; Johnson, KE; Kennicutt, RC; Krumholz, MR; Messa, M; Nair, P; Nota, A; Pellerin, A; Ryon, JE; Schaerer, D; Shabani, F; Van Dyk, SD; Whitmore, BC; Wofford, A

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dc.creator	Kahre, L
dc.creator	Walterbos, RA
dc.creator	Kim, H
dc.creator	Thilker, D
dc.creator	Calzetti, D
dc.creator	Lee, JC
dc.creator	Sabbi, E
dc.creator	Ubeda, L
dc.creator	Aloisi, A
dc.creator	Cignoni, M
dc.creator	Cook, DO
dc.creator	Dale, DA
dc.creator	Elmegreen, BG
dc.creator	Elmegreen, DM
dc.creator	Fumagalli, M
dc.creator	Gallagher, JS
dc.creator	Gouliermis, DA
dc.creator	Grasha, K
dc.creator	Grebel, EK
dc.creator	Hunter, DA
dc.creator	Sacchi, E
dc.creator	Smith, LJ
dc.creator	Tosi, M
dc.creator	Adamo, A
dc.creator	Andrews, JE
dc.creator	Ashworth, G
dc.creator	Bright, SN
dc.creator	Brown, TM
dc.creator	Chandar, R
dc.creator	Christian, C
dc.creator	De Mink, SE
dc.creator	Dobbs, C
dc.creator	Evans, AS
dc.creator	Herrero, A
dc.creator	Johnson, KE
dc.creator	Kennicutt, RC
dc.creator	Krumholz, MR
dc.creator	Messa, M
dc.creator	Nair, P
dc.creator	Nota, A
dc.creator	Pellerin, A
dc.creator	Ryon, JE
dc.creator	Schaerer, D
dc.creator	Shabani, F
dc.creator	Van Dyk, SD
dc.creator	Whitmore, BC
dc.creator	Wofford, A
dc.date	2018-11-23T15:52:58Z
dc.date	2018-03-16
dc.date	2018-11-23T15:52:58Z
dc.date.accessioned	2022-05-27T01:03:13Z
dc.date.available	2022-05-27T01:03:13Z
dc.identifier	Vol. 855, article 133
dc.identifier	10.3847/1538-4357/aab101
dc.identifier	http://hdl.handle.net/10871/34896
dc.identifier	0004-637X
dc.identifier	Astrophysical Journal
dc.identifier.uri	http://localhost:8080/xmlui/handle/CUHPOERS/241934
dc.description	This is the final version. Available from American Astronomical Society via the DOI in this record
dc.description	We present a study of the dust-to-gas ratios in five nearby galaxies: NGC 628 (M74), NGC 6503, NGC 7793, UGC 5139 (Holmberg I), and UGC 4305 (Holmberg II). Using Hubble Space Telescope broadband WFC3/UVIS UV and optical images from the Treasury program Legacy ExtraGalactic UV Survey (LEGUS) combined with archival HST/Advanced Camera for Surveys data, we correct thousands of individual stars for extinction across these five galaxies using an isochrone-matching (reddening-free Q) method. We generate extinction maps for each galaxy from the individual stellar extinctions using both adaptive and fixed resolution techniques and correlate these maps with neutral H i and CO gas maps from the literature, including the H i Nearby Galaxy Survey and the HERA CO-Line Extragalactic Survey. We calculate dust-to-gas ratios and investigate variations in the dust-to-gas ratio with galaxy metallicity. We find a power-law relationship between dust-to-gas ratio and metallicity, consistent with other studies of dust-to-gas ratio compared to metallicity. We find a change in the relation when H2is not included. This implies that underestimation of in low-metallicity dwarfs from a too-low CO-to-H2conversion factor XCOcould have produced too low a slope in the derived relationship between dust-to-gas ratio and metallicity. We also compare our extinctions to those derived from fitting the spectral energy distribution (SED) using the Bayesian Extinction and Stellar Tool for NGC 7793 and find systematically lower extinctions from SED fitting as compared to isochrone matching.
dc.description	This work is based on observations made with the NASA/ ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy under NASA contract NAS 5-26555. These observations are associated with program 13364 (LEGUS). Support for program 13364 was provided by NASA through a grant from the Space Telescope Science Institute. LK and RAW acknowledge support from the Space Telescope Science institute (grant Numbers HST-GO13773.003-A). LK would additionally like to acknowledge support from the Gemini Observatory in La Serena, Chile. MF acknowledges support from the Science and Technology Facilities Council (grant Number ST/P000541/1). DAG kindly acknowledges financial support by the German Research Foundation (DFG) through program GO 1659/3-2. GA acknowledges support from the Science and Technology Facilities Council (ST/P000541/1 and ST/M503472/1).
dc.language	en
dc.publisher	American Astronomical Society / IOP Publishing
dc.rights	© 2018. The American Astronomical Society. All rights reserved.
dc.subject	dust, extinction
dc.subject	galaxies: dwarf
dc.subject	galaxies: ISM
dc.subject	galaxies: photometry
dc.subject	galaxies: spiral
dc.subject	ISM: general
dc.title	Extinction Maps and Dust-to-gas Ratios in Nearby Galaxies with LEGUS
dc.type	Article