2022 journal article

A 30 kpc Spatially Extended Clumpy and Asymmetric Galactic Outflow at z similar to 1.7


By: A. Shaban, R. Bordoloi, J. Chisholm, S. Sharma, K. Sharon, J. Rigby, M. Gladders, M. Bayliss ...

Source: Web Of Science
Added: September 12, 2022

Abstract We image the spatial extent of a cool galactic outflow with fine-structure Fe ii * emission and resonant Mg ii emission in a gravitationally lensed star-forming galaxy at z = 1.70347. The Fe ii * and Mg ii (continuum-subtracted) emissions span out to radial distances of ∼14.33 and 26.5 kpc, respectively, with maximum spatial extents of ∼21 kpc for Fe ii * emission and ∼30 kpc for Mg ii emission. Mg ii emission is patchy and covers a total area of ∼184 kpc 2 , constraining the minimum area covered by the outflowing gas to be ∼13% of the total area. Mg ii emission is asymmetric and shows ∼21% more extended emission along the decl. direction. We constrain the covering fractions of the Fe ii * and Mg ii emission as a function of radial distance and characterize them with a power-law model. The Mg ii 2803 emission line shows two kinematically distinct emission components and may correspond to two distinct shells of outflowing gas with a velocity separation of Δ v ∼ 400 km s −1 . By using multiple images with different magnifications of the galaxy in the image plane, we trace the Fe ii * and Mg ii emissions around three individual star-forming regions. In all cases, both the Fe ii * and Mg ii emissions are more spatially extended compared to the star-forming regions traced by the [O ii ] emission. These findings provide robust constraints on the spatial extent of the outflowing gas and, combined with outflow velocity and column density measurements, will give stringent constraints on mass-outflow rates of the galaxy.