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.

Metal Enrichment in the Circumgalactic Medium and Lyα Halos around Quasars at z ∼ 3 / Guo Y.; Maiolino R.; Jiang L.; Matsuoka K.; Nagao T.; Dors O.L.; Ginolfi M.; Henden N.; Bennett J.; Sijacki D.; Puchwein E.. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - ELETTRONICO. - 898:(2020), pp. 26.0-26.0. [10.3847/1538-4357/ab9b7f]

Metal Enrichment in the Circumgalactic Medium and Lyα Halos around Quasars at z ∼ 3

Ginolfi M.;
2020

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.
898
0
0
Guo Y.; Maiolino R.; Jiang L.; Matsuoka K.; Nagao T.; Dors O.L.; Ginolfi M.; Henden N.; Bennett J.; Sijacki D.; Puchwein E.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2158/1289318
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 13
  • ???jsp.display-item.citation.isi??? ND
social impact