A 30 kpc Spatially Extended Clumpy and Asymmetric Galactic Outflow at z $\sim$ 1.7

Abstract

We image the spatial extent of a cool galactic outflow with fine structure Fe II${}^{\ast }$ emission and resonant Mg II emission in a gravitationally lensed star-forming galaxy at $z=1.70347$. The Fe II${}^{\ast }$ and Mg II (continuum-subtracted) emissions span out to radial distances of $\sim$14.33 kpc and 26.5 kpc, respectively, with maximum spatial extents of $\sim$21 kpc for Fe II${}^{\ast }$ emission and $\sim$30 kpc for Mg II emission. Mg II residual emission is patchy and covers a total area of $\sim$184 kpc${}^2$, constraining the minimum area covered by the outflowing gas to be $\sim$13% of the total area. Mg II emission is asymmetric and shows $\sim$21% more extended emission along the declination direction. We constrain the covering fractions of the Fe II${}^{\ast }$ 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 $\Delta v\sim$ 400 km/s. By using multiple images with different magnifications of the galaxy in the image plane, we trace the Fe II${}^{\ast }$, Mg II emissions around three individual star-forming regions. In all cases, both the Fe II${}^{\ast }$ 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.

22 pages, 14 figures, 4 tables, accepted to ApJ, the referee comments are incorporated in this version

References in corpus (17)

• The Circumgalactic Medium
• The MUSE second-generation VLT instrument
• A Bayesian approach to strong lensing modelling of galaxy clusters
• Ubiquitous outflows in DEEP2 spectra of star-forming galaxies at z=1.4
• Multi-scale cluster lens mass mapping I. Strong Lensing modelling
• A Review of Recent Observations of Galactic Winds Driven by Star Formation
• A 100-kiloparsec wind feeding the circumgalactic medium of a massive compact galaxy
• Optically-Thin Spatially-Resolved Mg II Emission Maps the Escape of Ionizing Photons
• Nuclear Outflow of the Milky Way: Studying the Kinematics and Spatial Extent of the Northern Fermi Bubble
• A clumpy and anisotropic galaxy halo at z=1 from gravitational-arc tomography
• MusE GAs FLOw and Wind (MEGAFLOW) VIII. Discovery of a MgII emission halo probed by a quasar sightline
• The cold circumgalactic medium in emission: MgII halos in TNG50
• The MUSE Hubble Ultra Deep Field Survey: VII. FeII* Emission in Star-Forming Galaxies
• Feeding the fire: Tracing the mass-loading of 10^7 K galactic outflows with O VI absorption
• Hydrogen Emission from the Ionized Gaseous Halos of Low Redshift Galaxies
• ALMA resolves the molecular gas in a young low-metallicity starburst galaxy at z=1.7
• Resolved galactic superwinds reconstructed around their host galaxies at z>3

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• Spatially Resolved Circumgalactic Medium around a Star-Forming Galaxy Driving a Galactic Outflow at $z\approx 0.8$
• The Transition from Galaxy-wide Gas Inflow to Outflow in Quasar Host Galaxies
• Modeling Emission-Line Surface Brightness in a Multiphase Galactic Wind: An O VI Case Study