Metallicity Relation Of Galaxies Research Articles

Quantifying AGN-driven metal-enhanced outflows in chemodynamical simulations

Abstract We show the effects of AGN-driven outflows on the ejection of heavy elements using our cosmological simulations, where supermassive black holes originate from the first stars. In the most massive galaxy, we have identified two strong outflows unambiguously driven by active galactic nucleus (AGN) feedback. These outflows have a speed greater than ∼8000 km s−1 near the AGN, and travel out to a half Mpc with ∼3000 km s−1. These outflows remove the remaining gas (∼3 per cent of baryons) and significant amounts of metals (∼2 per cent of total produced metals) from the host galaxy, chemically enriching the circumgalactic medium (CGM) and the intergalactic medium (IGM). 17.6 per cent of metals from this galaxy, and 18.4 per cent of total produced metals in the simulation, end up in the CGM and IGM, respectively. The metallicities of the CGM and IGM are higher with AGN feedback, while the mass–metallicity relation of galaxies is not affected very much. We also find ‘selective’ mass-loss where iron is more effectively ejected than oxygen because of the time delay of Type Ia supernovae. AGN-driven outflows play an essential role not only in quenching of star formation in massive galaxies to match with observed downsizing phenomena, but also in a large-scale chemical enrichment in the Universe. Observational constraints of metallicities and elemental abundance ratios in outflows are important to test the modelling of AGN feedback in galaxy formation.

Does the Amati Relation depend on the Luminosity of the GRB's Host Galaxy?

In order to test the systematics of the Amati relation, 24 long-duration GRBs with available Eγ,iso and Ep are separated into two subgroupsaccording to the B-band luminosity of their host galaxies. The Amati relations in the two subgroups are found to be in agreement with each other within the uncertainties. Taking into account of the well established luminos- ity - metallicity relation of galaxies, no strong evolution of the Amati relation with the GRB's environmental metallicity is implied in this study.