Modeling feedback from stars and black holes in galaxy mergers
نویسندگان
چکیده
We describe techniques for incorporating feedback from star formation and black hole accretion into simulations of isolated and merging galaxies. At present, the details of these processes cannot be resolved in simulations on galactic scales. Our basic approach therefore involves forming coarse-grained representations of the properties of the interstellar medium and black hole accretion starting from basic physical assumptions, so that the impact of these effects can be included on resolved scales. We illustrate our method using a multiphase description of star-forming gas. Feedback from star formation pressurises highly overdense gas, altering its effective equation of state. We show that this allows the construction of stable galaxy models with much larger gas fractions than possible in earlier numerical work. We extend the model by including a treatment of gas accretion onto central supermassive black holes in galaxies. Assuming thermal coupling of a small fraction of the bolometric luminosity of accreting black holes to the surrounding gas, we show how this feedback regulates the growth of black holes. In gas-rich mergers of galaxies, we observe a complex interplay between starbursts and central AGN activity when the tidal interaction triggers intense nuclear inflows of gas. Once an accreting supermassive black hole has grown to a critical size, feedback terminates its further growth, and expels gas from the central region in a powerful quasar-driven wind. Our simulation methodology is therefore able to address the coupled processes of gas dynamics, star formation, and black hole accretion during the formation of galaxies.
منابع مشابه
Termination of star formation by BH feedback in equal- and unequal- mass mergers of disk and elliptical galaxies
We present binary galaxy merger simulations of gas-rich disks (Sp-Sp), of early-type galaxies and disks (E-Sp, mixed mergers), and mergers of early-type galaxies (E-E, dry mergers) with varying mass ratios and different progenitor morphologies. The simulations include radiative cooling, star formation and black hole (BH) accretion and the associated feedback processes. We find for Sp-Sp mergers...
متن کاملBlack Holes in Galaxy Mergers: the Formation of Red Elliptical Galaxies
We use hydrodynamical simulations to study the color transformations induced by star formation and active galactic nuclei (AGN) during major mergers of spiral galaxies. Our modeling accounts for radiative cooling, star formation, and supernova feedback. Moreover, we include a treatment of accretion onto supermassive black holes embedded in the nuclei of the merging galaxies. We assume that a sm...
متن کاملEqual- and Unequal-mass Mergers of Disk and Elliptical Galaxies with Black Holes: the Mbh − Σ and Mbh −m∗ Relations
We present binary galaxy merger simulations with varying mass ratios and different progenitor morphologies. The simulations include mergers of gas-rich disks (Sp-Sp), of early-type galaxies and disks (E-Sp, mixed mergers), and mergers of early-type galaxies (E-E, dry mergers). We follow the dynamics of gas, stars and dark matter, and include radiative cooling, star formation and black hole (BH)...
متن کاملEqual- and Unequal-mass Mergers of Disk and Elliptical Galaxies with Black Holes
We present binary galaxy merger simulations with varying mass ratios and different progenitor morphologies. The simulations include mergers of gas-rich disks (Sp-Sp), of early-type galaxies and disks (E-Sp, mixed mergers), and mergers of early-type galaxies (E-E, dry mergers). We follow the dynamics of gas, stars and dark matter, and include radiative cooling, star formation and black hole (BH)...
متن کاملThe Relation between Quasar and Merging Galaxy Luminosity Functions and the Merger-induced Star Formation Rate of the Universe
Using a model for the self-regulated growth of supermassive black holes in mergers involving gas-rich galaxies, we study the relationship between quasars and the population of merging galaxies and, as a consequence, predict the merger-induced star formation rate density of the Universe. These mergers drive nuclear inflows of gas, fueling starbursts and “buried” quasar activity until feedback en...
متن کامل