The cold circumgalactic medium in emission: MgII halos in TNG50

Nelson, Dylan; Byrohl, Chris; Peroux, Celine; Rubin, Kate H. R.; Burchett, Joseph N.

doi:10.48550/arxiv.2106.09023

Cited by 7 publications

(13 citation statements)

References 101 publications

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“…Despite the wealth of observational data, a precise determination of the properties of winds and what drives them remains elusive because of inherent difficulties in disentangling the location and physical nature of the observed gas. Upcoming emission observations with KCWI and MUSE provide a promising path forward to greatly improve our understanding galactic wind as has been recently demonstrated observationally (Hayes et al 2016;Rupke et al 2019;Burchett et al 2021) and theoretically (e.g., Nelson et al 2021).…”

Section: Observing Galactic Windsmentioning

confidence: 99%

The Structure of Multiphase Galactic Winds

Fielding,

Bryan

2021

Preprint

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We present a novel analytic framework to model the steady-state structure of multiphase galactic winds comprised of a hot, volume-filling component and a cold, clumpy component. We first derive general expressions for the structure of the hot phase for arbitrary mass, momentum, and energy sources terms. Next, informed by recent simulations, we parameterize the cloud-wind mass transfer rates, which are set by the competition between turbulent mixing and radiative cooling. This enables us to cast the cloud-wind interaction as a source term for the hot phase and thereby simultaneously solve for the evolution of both phases fully accounting for their bidirectional influence. With this model, we explore the nature of galactic winds over a broad range of conditions. We find that: (i) with realistic parameter choices, we naturally produce a hot, low-density wind that transports energy while entraining a significant flux of cold clouds, (ii) mixing dominates the cold cloud acceleration and decelerates the hot wind, (iii) during mixing thermalization of relative kinetic energy provides significant heating, (iv) systems with low hot-phase mass loading factors and/or star formation rates can sustain higher initial cold phase mass loading factors, but the clouds are quickly shredded, and (v) systems with large hot-phase mass loading factors and/or star formation rates cannot sustain large initial cold-phase mass loading factors, but the clouds tend to grow with radius. Our results highlight the necessity of accounting for the multiphase structure of galactic winds, both physically and observationally, and have important implications for feedback in galactic systems.

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Section: Observing Galactic Windsmentioning

confidence: 99%

The Structure of Multiphase Galactic Winds

Fielding,

Bryan

2021

Preprint

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“…It simulates a representative ∼ 50 Mpc comoving side-length volume of the Universe with a baryonic mass resolution of ∼ 8 × 10 4 M , a median spatial resolution of ∼ 150 parsecs in the star-forming ISM, decreasing to better than 2 kpc within the virial radius of such massive ( 10 13 𝑀 ) halos. TNG50 has shown diverse manifestations of hydrodynamical phenomenon related to gaseous halos, including the aforementioned cold phase clouds, the production of Lyman-alpha halos at high-redshift (Byrohl et al 2020), the generation of outflow-driven bubbles around Milky Way and M31-like galaxies similar to the Fermi bubbles (Pillepich et al 2021), ultraviolet metal-line emission from MgII in the CGM (Nelson et al 2021), and observable predictions for an azimuthal angle modulation of CGM metallicity (Péroux et al 2020) as well as satellite galaxy quenching (Martín-Navarro et al 2021).…”

Section: Comparison With Cold Clouds In the Tng50 Cosmological Simula...mentioning

confidence: 99%

“…While the CGM of typical star-forming galaxies has often been explored using quasar absorption studies (see Tumlinson et al 2017 for a review), emission directly probes the radiative losses and the concomitant flow of mass across temperature phases (Bertone & Schaye 2012;Corlies & Schiminovich 2016;Nelson et al 2021). However, our work shows that one cannot rely on a simple cooling flow model across all temperature ranges.…”

Section: Differential Emission From Gas In and Around Cold Cloudsmentioning

confidence: 99%

Cooling flows around cold clouds in the circumgalactic medium: steady-state models & comparison with TNG50

Dutta,

Sharma,

Nelson

2021

Preprint

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Cold, non-self-gravitating clumps occur in various astrophysical systems, ranging from the interstellar and circumgalactic medium (CGM), to AGN outflows and solar coronal loops. Cold gas has diverse origins such as turbulent mixing or precipitation from hotter phases. We obtain the analytic solution for a steady pressure-driven 1-D cooling flow around cold over-densities, irrespective of their origin. Our solutions describe the slow and steady radiative cooling-driven local gas inflow in the saturated regime of nonlinear thermal instability in clouds, sheets and filaments. We use a simple two-fluid treatment to include magnetic fields as an additional polytropic fluid. To test the limits of applicability of these analytic solutions, we compare with the gas structure found in and around small-scale cold clouds in the CGM of massive halos in the TNG50 cosmological MHD simulation from the IllustrisTNG suite. Despite qualitative resemblance of the gas structure, we find that deviations from steady state, complex geometries and turbulence all add complexity beyond our analytic solutions. We derive an exact relation between the mass cooling rate ( M cool ) and the radiative cooling rate ( E cool ) for a steady cooling flow. A comparison with the TNG50 clouds shows that this cooling flow relation applies in a narrow temperature range around ∼ 10 4.5 K where the isobaric cooling time is the shortest. In general, turbulence and mixing, instead of radiative cooling, may dominate the transition of gas between different temperature phases.

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“…Recent theoretical works have also reported how the CGM of galaxies will look in Mg II emission. Nelson et al (2021) reprocessed the TNG50 simulations to study the Mg II halos in the CGM of galaxies within redshift range 0.3 < z < 2 and stellar mass range 7.5 < log(M * /M ) < 11. They assumed that Mg II emission is optically thin and they neglect the impact of resonant scattering.…”

Section: Mg II Emission Radial Profilesmentioning

confidence: 99%

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

Shaban,

Bordoloi,

Chisholm

et al. 2021

Preprint

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We image the spatial extent of a cool galactic outflow with resonant Mg II emission in a gravitationally lensed star-forming galaxy at z ∼ 1.7 using VLT/MUSE observations. We observe Mg II residual (continuum-subtracted) emission out to an observed radial distance of 26.5 +0.5 −0.4 kpc from the galaxy, with an observed maximum spatial extent of ≈ 39 +0.8 −0.6 kpc (30 +0.7 −0.5 kpc after correcting for seeing). Mg II residual emission is patchy and covers a total area of 184 +5 −10 kpc 2 , constraining the minimum area covered by the outflowing gas to be 13.27 +0.55 −1.02 % of the total area. The spatial extent of the Mg II emission is asymmetric and shows an observed 27.6 +0.8 −0.7 % (20.9 +0.7 −0.6 % after seeing correction) larger extent along the declination direction. We constrain the covering fraction of the Mg II emission as a function of radial distance and characterize it with a power-law model convolved with the seeing with an index γ = −1.25 +0.02 −0.02 . We find two kinematically distinct Mg II emission components (∆v ≈ 400 km s −1 ) which extend out to similar distances, and may correspond to two distinct shells of outflowing gas. By using multiple images with different magnifications of the galaxy in the image plane, we trace the Mg II residual emission in three individual star-forming regions inside the galaxy out to 6.0 +0.2 −0.2 , 7.0 +0.3 −0.2 , and 8.5 +0.1 −0.1 kpc. Both the Fe II * fine structure emission, and the nebular [O II] emission are not spatially extended relative to the stellar continuum. 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.

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The cold circumgalactic medium in emission: MgII halos in TNG50

Cited by 7 publications

References 101 publications

The Structure of Multiphase Galactic Winds

The Structure of Multiphase Galactic Winds

Cooling flows around cold clouds in the circumgalactic medium: steady-state models & comparison with TNG50

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

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