The Cosmic Ultraviolet Baryon Survey: Empirical Characterization of Turbulence in the Cool Circumgalactic Medium

This paper reports the first measurement of the relationship between turbulent velocity and cloud size in the diffuse circumgalactic medium (CGM) in typical galaxy halos at redshift z ≈ 0.4–1. Through spectrally resolved absorption profiles of a suite of ionic transitions paired with careful ionizat...

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Veröffentlicht in:Astrophysical journal. Letters 2023-09, Vol.955 (1), p.L25
Hauptverfasser: Chen, Hsiao-Wen, Qu, Zhijie, Rauch, Michael, Chen, Mandy C., Zahedy, Fakhri S., Johnson, Sean D., Schaye, Joop, Rudie, Gwen C., Boettcher, Erin, Cantalupo, Sebastiano, Faucher-Giguère, Claude-André, Greene, Jenny E., Lopez, Sebastian, Simcoe, Robert A.
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Sprache:eng
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Zusammenfassung:This paper reports the first measurement of the relationship between turbulent velocity and cloud size in the diffuse circumgalactic medium (CGM) in typical galaxy halos at redshift z ≈ 0.4–1. Through spectrally resolved absorption profiles of a suite of ionic transitions paired with careful ionization analyses of individual components, cool clumps of size as small as l cl ∼ 1 pc and density lower than n H = 10 −3 cm −3 are identified in galaxy halos. In addition, comparing the line widths between different elements for kinematically matched components provides robust empirical constraints on the thermal temperature T and the nonthermal motions b NT , independent of the ionization models. On average, b NT is found to increase with l cl following b NT ∝ l cl 0.3 over three decades in spatial scale from l cl ≈ 1 pc to l cl ≈ 1 kpc. Attributing the observed b NT to turbulent motions internal to the clumps, the best-fit b NT – l cl relation shows that the turbulence is consistent with Kolmogorov at
ISSN:2041-8205
2041-8213
DOI:10.3847/2041-8213/acf85b