Active galactic nuclei and massive galaxy cores
Résumé
Context: Central active galactic nuclei (AGN) are supposed to play a key role in the evolution of their host galaxies. In particular, the dynamical and physical properties of the gas core must be affected by the injected energy.
Aims: Our aim is to study the effects of an AGN on the dark matter profile and on the central stellar light distribution in massive early type galaxies.
Methods: By performing self-consistent N-body simulations, we assume in our analysis that periodic bipolar outbursts from a central AGN can induce harmonic oscillatory motions on both sides of the gas core.
Results: Using realistic AGN properties, we find that the motions of the gas core, driven by such feedback processes, can flatten the dark matter and/or stellar profiles after 4-5 Gyr. These results are consistent with recent observational studies that suggest that most giant elliptical galaxies have cores or are “missing light” in their inner part. Since stars behave as a “collisionless” fluid similar to dark matter, the density profile both of stars and dark matter should be affected in a similar way, leading to an effective reduction in the central brightness.
Aims: Our aim is to study the effects of an AGN on the dark matter profile and on the central stellar light distribution in massive early type galaxies.
Methods: By performing self-consistent N-body simulations, we assume in our analysis that periodic bipolar outbursts from a central AGN can induce harmonic oscillatory motions on both sides of the gas core.
Results: Using realistic AGN properties, we find that the motions of the gas core, driven by such feedback processes, can flatten the dark matter and/or stellar profiles after 4-5 Gyr. These results are consistent with recent observational studies that suggest that most giant elliptical galaxies have cores or are “missing light” in their inner part. Since stars behave as a “collisionless” fluid similar to dark matter, the density profile both of stars and dark matter should be affected in a similar way, leading to an effective reduction in the central brightness.
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