Dust-to-Gas Ratio in the Extremely Metal Poor Galaxy I ZW 18

Дата и время публикации : 2012-04-20T20:53:05Z

Авторы публикации и институты :
Rodrigo Herrera-Camus
David B. Fisher
Alberto D. Bolatto
Adam K. Leroy
Fabian Walter
Karl. D. Gordon
Julia Roman-Duval
Jessica Donaldson
Marcio Meléndez
John M. Cannon

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: Accepted for publication in ApJ: 8 pages, 4 figures, 1 table
Первичная категория: astro-ph.CO

Все категории : astro-ph.CO, astro-ph.GA

Краткий обзор статьи: 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 {it Spitzer}, {it 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 $J=1rightarrow0$ transition. We use dust emission models to derive a dust mass upper limit of only M$_{dust}leq1.1times10^4$ M$_{odot}$ ($3sigma$ limit). This upper limit is driven by the non-detection at 160 $mu$m, and it is a factor of 4-10 times smaller than previous estimates (depending upon the model used). We also estimate an upper limit to the total dust-to-gas mass ratio of M$_{Dust}$/M$_{gas}leq5.0times10^{-5}$. If a linear correlation between the dust-to-gas mass ratio and metallicity (measure as O/H) were to hold, we would expect a ratio of 3.9$times10^{-4}$. We also show that the infrared SED is similar to that of starbursting systems.

Category: Physics