Year: 2020
Type: article
Abstract: Deep observations have detected extended Lyα 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 80 quasars at z ∼ 3 based on MUSE-VLT data. We find clear evidence of extended emission of the UV nebular lines such as C iv λ1549 or He ii λ1640 for about 20% of the sample, while C iii] λ1909 is only marginally detected in a few objects. By stacking the cubes, we detect emission of C iv, He ii, and C iii] out to a radius of about 45 kpc. C iv and He ii show a radial decline much steeper than Lyα, while C iii] shows a shallower profile similar to Lyα in the inner 45 kpc. We infer that the average metallicity of the circumgalactic gas within the central 30–50 kpc is ∼0.5 solar, or even higher. However, we also find evidence of a component of the Lyα halos, which has much weaker metal emission lines relative to Lyα. We suggest that the high metallicity of the circumgalactic medium within the central 30–50 kpc is associated with chemical pre-enrichment by past quasar-driven outflows and that there is a more extended component of the circumgalactic medium that has much lower metallicity and is likely associated with near-pristine gas accreted from the intergalactic medium. We show that our observational results are in good agreement with the expectations of the FABLE zoom-in cosmological simulations.
Source: The Astrophysical Journal
Authors: Yucheng Guo, Roberto Maiolino, Linhua Jiang, Kenta Matsuoka, Tohru Nagao, Oli Luiz Dors, Michele Ginolfi, Nick Henden, Jake Bennett, Debora Sijacki, Ewald Puchwein
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: Support of the astronomical research of the Cavendish Astrophysics Group, G1945644245, DiRAC-3 Operations 2019-2022 - Edinburgh, REVEALING THE STRUCTURE OF THE UNIVERSE: GRAVITATIONAL WAVES, COSMOLOGY AND EXOPLANETS, Consolidated Grant Astronomy Observation and Theory 2019-2022, G373332812, STFC DiRAC Project Office 2014-2017, Revealing the Structure of the Universe: From Extreme Gravity to Exoplanets, DiRAC-2 Datacentric support grant, G4248713385, DiRAC SMP Facility: The Structure of the Universe, A pathfinder project for a National AAAI, DiRAC 2.5 Operations Bridging 2019 - Leicester, Astronomy Observation and Theory Consolidated Grant 2016-2019, Dirac-3 Operations 2019-2022- Durham, DiRAC 3 Operations, DiRAC-2: Recurrent Costs for Complexity@DiRAC Cluster at University of Leicester, Unveiling the Structure of the Universe, DiRAC-2.5 DC - Operations 2017-2020, Dirac-3 Operations 2019-2022- Durham, Resources for DiRAC2 at HPCs, Dirac 2.5 Operations, DiRAC2.5 Operations: The DiRAC Project Office 2017-2020, DiRAC 2.5y Bridging Funding - UCL, Edinburgh DiRAC Resource Grant, G7285151123, The Structure of the Universe: Cosmology, Exoplanets and Lattice QCD, DiRAC SMP Facility: Revealing the Structure of the Universe, Exploring the evolution of supermassive black holes through the synergetic wide-field observations with Subaru/HSC and eROSITA, G7937591081, DiRAC Bridging Grant 2019, Software development support for DiRAC, G8931419319, DiRAC 2.5 Operations 2017-2020
OpenAlex ID: W3000473092