Document Type

Article

Publication Date

5-27-2010

Publication Title

The Astrophysical Journal

DOI

10.1088/0004-637X/716/2/1095

ISSN

1538-4357

Abstract

We compare the substructure evolution in pure dark matter (DM) halos with those in the presence of baryons, hereafter PDM and BDM models, respectively. The prime halos have been analyzed in the previous work. Models have been evolved from identical initial conditions which have been constructed by means of the constrained realization method. The BDM model includes star formation and feedback from stellar evolution onto the gas. A comprehensive catalog of subhalo populations has been compiled and individual and statistical properties of subhalos analyzed, including their orbital differences. We find that subhalo population mass functions in PDM and BDM are consistent with a single power law, M α sbh, for each of the models in the mass range of ~2 × 108 M ☉-2 × 1011 M ☉. However, we detect a nonnegligible shift between these functions, the time-averaged α ~ –0.86 for the PDM and –0.98 for the BDM models. Overall, α appears to be a nearly constant in time, with variations of ±15%. Second, we find that the radial mass distribution of subhalo populations can be approximated by a power law, with a steepening that occurs at the radius of a maximal circular velocity, R vmax, in the prime halos. Here we find that γsbh ~ –1.5 for the PDM and –1 for the BDM models, when averaged over time inside R vmax. The slope is steeper outside this region and approaches –3. We detect little spatial bias (less than 10%) between the subhalo populations and the DM distribution of the main halos. Also, the subhalo population exhibits much less triaxiality in the presence of baryons, in tandem with the shape of the prime halo. Finally, we find that, counter-intuitively, the BDM population is depleted at a faster rate than the PDM one within the central 30 kpc of the prime halo. The reason for this is that although the baryons provide a substantial glue to the subhalos, the main halo exhibits the same trend. This assures a more efficient tidal disruption of the BDM subhalo population. However, this effect can be reversed for a more efficient feedback from stellar evolution and the central supermassive black holes, which will expel baryons from the center and decrease the central concentration of the prime halo. We compare our results with via Lactea and Aquarius simulations and other published results.

Published copy located at:https://iopscience.iop.org/article/10.1088/0004-637X/716/2/1095

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Notes/Citation Information

Link to Journal Copyright: https://journals.aas.org/article-charges-and-copyright/

Published in The Astrophysical Journal Letters, v. 716, no. 2, p. 1095-1104.

© 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

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