Published April 26, 2021
| Version v1
Presentation
Open
Metal Enrichment in the Circumgalactic Medium and Lya Halos around Quasars at z~3
Authors/Creators
- 1. The Kavli Institute for Astronomy and Astrophysics, Peking University , China
Description
Deep observations have detected extended Lya emission nebulae surrounding tens of quasars at redshift 2–6. However, the metallicity of such extended halos is still poorly understood. We perform a detailed analysis on a large sample of quasars at z~3 based on MUSE-VLT data. We find clear evidence of extended emission of CIV1549, HeII1640 and CIII]1909 out to a radius of ~45 kpc. We infer that the average metallicity of the CGM gas within the central 30–50 kpc is ~0.5 solar, or even higher. We also find evidence of a component of the Lya halos, which has much weaker metal emission lines relative to Lya. We suggest that the high metallicity of the CGM within the central 30–50 kpc is associated with chemical pre-enrichment by past quasar-driven outflows and that there is a more extended metal-poor component of the CGM that is likely associated with near-pristine gas accreted from the IGM. Our results are in good agreement with the expectations of the FABLE zoom-in cosmological simulations.
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Galspec2021_YuchengGuo.pdf
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