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A Testable Conspiracy: Simulating Baryonic Effects on Self-interacting Dark Matter Halos

Elbert, Oliver D. and Bullock, James S. and Kaplinghat, Manoj and Garrison-Kimmel, Shea and Graus, Andrew S. and Rocha, Miguel (2018) A Testable Conspiracy: Simulating Baryonic Effects on Self-interacting Dark Matter Halos. Astrophysical Journal, 853 (2). Art. No. 109. ISSN 1538-4357.

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We investigate the response of self-interacting dark matter (SIDM) halos to the growth of galaxy potentials using idealized simulations, with each run in tandem with collisionless cold dark matter (CDM). We find that if the stellar potential strongly dominates in the central parts of a galaxy, then SIDM halos can be as dense as CDM halos on observable scales. For extreme cases, core collapse can occur, leading to SIDM halos that are denser and cuspier than their CDM counterparts. If the stellar potential is not dominant, then SIDM halos retain isothermal cores with densities far below CDM predictions. When a disk is present, the inner SIDM halo becomes more flattened in the disk plane than the CDM halo. These results are in excellent quantitative agreement with the predictions of Kaplinghat et al. We also simulated a cluster halo with a central stellar distribution similar to the brightest central galaxy of the cluster A2667. An SIDM halo simulated with the cross-section over mass σ/m =0.1 cm^2 g^(-1) provides a good match to the measured dark matter (DM) density profile, while an adiabatically contracted CDM halo is denser and cuspier. The profile of the same halo simulated with σ/m = 0.5 cm^2 g^(-1) is not dense enough. Our findings are in agreement with previous results that σ/m\ ≳ 0.1 cm^2 g^(1-) is disfavored for DM collision velocities above about 1500 km s^(−1). More generally, the interaction between baryonic potentials and SIDM densities offers new directions for constraining SIDM cross-sections in galaxies where baryons are dynamically important.

Item Type:Article
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URLURL TypeDescription Paper
Bullock, James S.0000-0003-4298-5082
Garrison-Kimmel, Shea0000-0002-4655-8128
Additional Information:© 2018. The American Astronomical Society. Received 2017 June 16; revised 2017 October 18; accepted 2017 October 27; published 2018 January 26. The authors thank Michael Boylan-Kolchin and Hai-Bo Yu for valuable discussions. O.D.E., A.S.G., and J.S.B. were supported by the National Science Foundation (grants PHY-1520921, AST-1518291, and AST-1009973) and by NASA through HST (GO-13343) awarded by the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555. M.K. is supported by NSF grant PHY-1620638. Support for S.G.K. was provided by NASA through Einstein Postdoctoral Fellowship grant number PF5-160136 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060. This work also made use of Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration et al. 2013), matplotlib (Hunter 2007), numpy (van der Walt et al. 2011), scipy (Jones et al. 2001), ipython (Perez & Granger 2007), and NASA's Astrophysics Data System. This work also made use of the EXtreme Science and Engineering Discovery Environment (XSEDE; Towns et al. 2014).
Funding AgencyGrant Number
NASA Einstein FellowshipPF5-160136
Subject Keywords:dark matter; galaxies: evolution
Issue or Number:2
Record Number:CaltechAUTHORS:20180201-112823834
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Official Citation:Oliver D. Elbert et al 2018 ApJ 853 109
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84622
Deposited By: George Porter
Deposited On:01 Feb 2018 22:36
Last Modified:15 Nov 2019 04:10

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