DUST-TO-GAS RATIO IN THE EXTREMELY METAL-POOR GALAXY I Zw 18

Content Provider	Scilit
Author	Herrera-Camus, Rodrigo Fisher, Deanne Bolatto, Alberto D. Leroy, Adam K. Walter, Fabian Gordon, Karl Roman-Duval, Julia Donaldson, Jessica Melendez, Marcio Cannon, John M.
Copyright Year	2012
Description	Journal: The Astrophysical Journal The blue compact dwarf galaxy I Zw 18 is one of the most metal-poor systems known in the local universe (12+log(O/H) = 7.17). In this work we study I Zw 18 using data from Spitzer, Herschel Space Telescope, and IRAM Plateau de Bure Interferometer. Our data set includes the most sensitive maps of I Zw 18, to date, in both the far-infrared and the CO J = 1 → 0 transition. We use dust emission models to derive a dust mass upper limit of only M$ _{dust}$ ≤ 1.1 × $10^{4}$ M$ _{☉}$ (3σ limit). This upper limit is driven by the non-detection at 160 μm, and it is a factor of 4-10 times smaller than previous estimates (depending on the model used). We also estimate an upper limit to the total dust-to-gas mass ratio of M$ _{Dust}$/M$ _{gas}$ ≤ 5.0 × $10^{–5}$. If a linear correlation between the dust-to-gas mass ratio and metallicity (measured as O/H) were to hold, we would expect a ratio of 3.9 × $10^{–4}$. We also show that the infrared spectral energy distribution is similar to that of starbursting systems.
Related Links	http://iopscience.iop.org/article/10.1088/0004-637X/752/2/112/pdf
ISSN	0004637X
DOI	10.1088/0004-637x/752/2/112
Journal	The Astrophysical Journal
Issue Number	2
Volume Number	752
Language	English
Publisher	IOP Publishing
Publisher Date	2012-06-20
Access Restriction	Open
Subject Keyword	Journal: The Astrophysical Journal Astronomy and Astrophysics Extragalactic Astronomy
Content Type	Text
Resource Type	Article
Subject	Astronomy and Astrophysics Space and Planetary Science