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http://hdl.handle.net/20.500.12386/35387
Title: | Chemical abundance of z ∼ 6 quasar broad-line regions in the XQR-30 sample | Authors: | Lai, Samuel Bian, Fuyan Onken, Christopher A. Wolf, Christian Mazzucchelli, Chiara Bañados, Eduardo BISCHETTI, Manuela Bosman, Sarah E. I. Becker, George CUPANI, Guido D'ODORICO, Valentina Eilers, Anna-Christina Fan, Xiaohui Farina, Emanuele Paolo Onoue, Masafusa Schindler, Jan-Torge Walter, Fabian Wang, Feige Yang, Jinyi Zhu, Yongda |
Issue Date: | 2022 | Journal: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Number: | 513 | Issue: | 2 | First Page: | 1801 | Abstract: | The elemental abundances in the broad-line regions of high-redshift quasars trace the chemical evolution in the nuclear regions of massive galaxies in the early Universe. In this work, we study metallicity-sensitive broad emission-line flux ratios in rest-frame UV spectra of 25 high-redshift (5.8 < z < 7.5) quasars observed with the VLT/X-shooter and Gemini/GNIRS instruments, ranging over $\log \left({{M}_{\rm {BH}}/\rm {M}_{\odot }}\right) = 8.4-9.8$ in black hole mass and $\log \left(\rm {L}_{\rm {bol}}/\rm {erg \, s}^{-1}\right) = 46.7-47.7$ in bolometric luminosity. We fit individual spectra and composites generated by binning across quasar properties: bolometric luminosity, black hole mass, and blueshift of the C IV line, finding no redshift evolution in the emission-line ratios by comparing our high-redshift quasars to lower redshift (2.0 < z < 5.0) results presented in the literature. Using CLOUDY-based locally optimally emitting cloud photoionization model relations between metallicity and emission-line flux ratios, we find the observable properties of the broad emission lines to be consistent with emission from gas clouds with metallicity that are at least 2-4 times solar. Our high-redshift measurements also confirm that the blueshift of the C IV emission line is correlated with its equivalent width, which influences line ratios normalized against C IV. When accounting for the C IV blueshift, we find that the rest-frame UV emission-line flux ratios do not correlate appreciably with the black hole mass or bolometric luminosity. | URI: | http://hdl.handle.net/20.500.12386/35387 | URL: | https://academic.oup.com/mnras/article/513/2/1801/6566349 http://arxiv.org/abs/2204.03335v1 |
ISSN: | 0035-8711 | DOI: | 10.1093/mnras/stac1001 | Bibcode ADS: | 2022MNRAS.513.1801L | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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lai2022.pdf | PDF editoriale | 2.7 MB | Adobe PDF | View/Open |
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