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http://hdl.handle.net/20.500.12386/30701
Title: | Quasar outflows at z ≥ 6: the impact on the host galaxies | Authors: | BARAI, Paramita GALLERANI, Simona Pallottini, Andrea Ferrara, Andrea Marconi, Alessandro CICONE, CLAUDIA Maiolino, Roberto Carniani, Stefano |
Issue Date: | 2018 | Journal: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Number: | 473 | Issue: | 3 | First Page: | 4003 | Abstract: | We investigate quasar outflows at z ≥ 6 by performing zoom-in cosmological hydrodynamical simulations. By employing the smoothed particle hydrodynamics code GADGET-3, we zoom in the 2R<SUB>200</SUB> region around a 2 × 10<SUP>12</SUP> M<SUB>☉</SUB> halo at z = 6, inside a (500 Mpc)<SUP>3</SUP> comoving volume. We compare the results of our active galactic nuclei (AGN) runs with a control simulation in which only stellar/SN feedback is considered. Seeding 10<SUP>5</SUP> M<SUB>☉</SUB> black holes (BHs) at the centres of 10<SUP>9</SUP> M<SUB>☉</SUB> haloes, we find the following results. BHs accrete gas at the Eddington rate over z = 9-6. At z = 6, our most-massive BH has grown to M<SUB>BH</SUB> = 4 × 10<SUP>9</SUP> M<SUB>☉</SUB>. Fast (v<SUB>r</SUB> > 1000 km s<SUP>-1</SUP>), powerful (\dot{M}_out ∼ 2000 M_{☉} yr<SUP>-1</SUP>) outflows of shock-heated low-density gas form at z ∼ 7, and propagate up to hundreds kpc. Star formation is quenched over z = 8-6, and the total star formation rate (SFR surface density near the galaxy centre) is reduced by a factor of 5 (1000). We analyse the relative contribution of multiple physical process: (i) disrupting cosmic filamentary cold gas inflows, (ii) reducing central gas density, (iii) ejecting gas outside the galaxy; and find that AGN feedback has the following effects at z = 6. The inflowing gas mass fraction is reduced by ∼ 12 per cent, the high-density gas fraction is lowered by ∼ 13 per cent, and ∼ 20 per cent of the gas outflows at a speed larger than the escape velocity (500 km s<SUP>-1</SUP>). We conclude that quasar-host galaxies at z ≥ 6 are accreting non-negligible amount of cosmic gas, nevertheless AGN feedback quenches their star formation dominantly by powerful outflows ejecting gas out of the host galaxy halo. | URI: | http://hdl.handle.net/20.500.12386/30701 | URL: | https://academic.oup.com/mnras/article-abstract/473/3/4003/4349752?redirectedFrom=fulltext | ISSN: | 0035-8711 | DOI: | 10.1093/mnras/stx2563 | Bibcode ADS: | 2018MNRAS.473.4003B | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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stx2563.pdf | PDF editoriale | 14.36 MB | Adobe PDF | View/Open |
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