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Paper   IPM / Astronomy / 16827
School of Astronomy
  Title:   Clumpiness of observed and simulated cold circumgalactic gas
1.  R. Augustin
2.  C. PÃ?©roux
3.  A. Hamanowicz
4.  V. Kulkarni
5.  H. Rahmani
6.  A. Zanella
  Status:   Published
  Journal: MNRAS
  Vol.:  505
  Year:  2021
  Supported by:            ipm IPM
Determining the clumpiness of matter around galaxies is pivotal to a full understanding of the spatially inhomogeneous, multi-phase gas in the circumgalactic medium (CGM). We combine high spatially resolved 3D observations with hydrodynamical cosmological simulations to measure the cold circumgalactic gas clumpiness. We present new adaptive-optics-assisted VLT/MUSE observations of a quadruply lensed quasar, targeting the CGM of 2 foreground z�?�1 galaxies observed in absorption. We additionally use zoom-in FOGGIE simulations with exquisite resolution (�?�0.1 kpc scales) in the CGM of galaxies to compute the physical properties of cold gas traced by Mg\,II absorbers. By contrasting these mock-observables with the VLT/MUSE observations, we find a large spread of fractional variations of Mg\,II equivalent widths with physical separation, both in observations and simulations. The simulations indicate a dependence of the Mg\,II coherence length on the underlying gas morphology (filaments vs clumps). The zabs=1.168 Mg\,II system shows coherence over �?� 6 kpc and is associated with an [O\,II] emitting galaxy situated 89 kpc away, with SFR �?� 4.6 ± {1.5} M�??/yr and M�??=109.6±0.2M�??. Based on this combined analysis, we determine that the absorber is consistent with being an inflowing filament. The zabs=1.393 Mg\,II system traces dense CGM gas clumps varying in strength over �?� 2 kpc physical scales. Our findings suggest that this absorber is likely related to an outflowing clump. Our joint approach combining 3D-spectroscopy observations of lensed systems and simulations with extreme resolution in the CGM put new constraints on the clumpiness of cold CGM gas, a key diagnostic of the baryon cycle

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