تقرير
The Cosmic Ultraviolet Baryon Survey: Empirical Characterization of Turbulence in the Cool Circumgalactic Medium
| العنوان: | The Cosmic Ultraviolet Baryon Survey: Empirical Characterization of Turbulence in the Cool Circumgalactic Medium |
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| المؤلفون: | 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-Giguere, Claude-Andre, Greene, Jenny E., Lopez, Sebastian, Simcoe, Robert A. |
| سنة النشر: | 2023 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies |
| الوصف: | 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 nH = 0.001 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 non-thermal motions bNT, independent of the ionization models. On average, bNT is found to increase with l_cl following bNT \propto l_cl^0.3 over three decades in spatial scale from l_cl~1 pc to l_cl~1 kpc. Attributing the observed bNT to turbulent motions internal to the clumps, the best-fit bNT-l_cl relation shows that the turbulence is consistent with Kolmogorov at <1 kpc with a roughly constant energy transfer rate per unit mass of epsilon~0.003 cm^2 s^-3 and a dissipation time scale of <~ 100 Myr. No significant difference is found between massive quiescent and star-forming halos in the sample on scales less than 1 kpc. While the inferred epsilon is comparable to what is found in CIV absorbers at high redshift, it is considerably smaller than observed in star-forming gas or in extended line-emitting nebulae around distant quasars. A brief discussion of possible sources to drive the observed turbulence in the cool CGM is presented. Comment: Accepted for publication in ApJ Letters; 10 pages, 4 figures |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2309.05699 |
| رقم الأكسشن: | edsarx.2309.05699 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |