The DREAMS Project: Disentangling the Impact of Halo-to-halo Variance and Baryonic Feedback on Milky Way Dark Matter Density Profiles
Abstract In this work, we utilize a new suite of Milky Way–mass halos from the DREAMS Project, simulated with cold dark matter (CDM), to quantify the influence of baryon feedback and intrinsic halo-to-halo variance on dark matter density profiles. Our suite of 1024 halos varies over supernova and black hole feedback parameters from the IllustrisTNG model, as well as variations in two cosmological parameters. We find that, for the DREAMS parameter variations, Milky Way–mass dark matter density profiles in the IllustrisTNG model are largely insensitive to astrophysics and cosmology variations, with the dominant source of scatter instead arising from halo-to-halo variance. However, most of the (comparatively minor) feedback-driven variations come from the changes to supernova prescriptions. By comparing to dark-matter-only simulations, we find that the strongest supernova wind energies are so effective at preventing galaxy formation that the halos are nearly entirely collisionless dark matter. Finally, regardless of physics variation, all of the DREAMS halos are roughly consistent with a halo contracting adiabatically from the presence of baryons, unlike models that have bursty stellar feedback. This work represents a step toward assessing the uncertainty in Milky Way dark matter profiles, with direct implications for dark matter searches where systematic uncertainty in the density profile remains a major challenge.
Authors
- Nitya Kallivayalil (ORCID: https://orcid.org/0000-0002-3204-1742)
- Francisco Villaescusa-Navarro (ORCID: https://orcid.org/0000-0002-4816-0455)
- Mark Vogelsberger (ORCID: https://orcid.org/0000-0001-8593-7692)
- Mariangela Lisanti (ORCID: https://orcid.org/0000-0002-8495-8659)
- Stephanie O’Neil (ORCID: https://orcid.org/0000-0002-7968-2088)
- John R. Barry (ORCID: https://orcid.org/0000-0002-3565-6515)
- Andrew B. Pace (ORCID: https://orcid.org/0000-0002-6021-8760)
- Aklant K. Bhowmick (ORCID: https://orcid.org/0000-0002-7080-2864)
- Belén Costanza (ORCID: https://orcid.org/0009-0008-6301-1539)
- Hongwan Liu
- Jonah C. Rose (ORCID: https://orcid.org/0000-0002-2628-0237)
- Arya Farahi (ORCID: https://orcid.org/0000-0003-0777-4618)
- Xuejian Shen (ORCID: https://orcid.org/0000-0002-6196-823X)
- Xiaowei Ou (ORCID: https://orcid.org/0000-0002-4669-9967)
- Paul Torrey (ORCID: https://orcid.org/0000-0002-5653-0786)
- Lina Necib
- Jiaxuan Li (ORCID: https://orcid.org/0000-0001-9592-4190)
- Alex M. Garcia (ORCID: https://orcid.org/0000-0002-8111-9884)
- Niusha Ahvazi (ORCID: https://orcid.org/0009-0002-1233-2013)
- Jonathan Kho (ORCID: https://orcid.org/0000-0002-0275-3001)
- Ilem Leisher (ORCID: https://orcid.org/0009-0006-5740-5318)
- Ethan Lilie
Institutions
- Boston University (US)
- Northwestern University (US)
- Northeastern University (US)
- Consejo Nacional de Investigaciones Científicas y Técnicas (AR)
- Philipps University of Marburg (DE)
- Grinnell College (US)
- Princeton University (US)
- Simons Foundation (US)
- Flatiron Health (United States) (US)
- Istituto Nazionale di Fisica Nucleare, Sezione di Roma I (IT)
- The NSF AI Institute for Artificial Intelligence and Fundamental Interactions (US)
- Flatiron Institute (US)
- University of Virginia (US)
- Weizmann Institute of Science (IL)
- Massachusetts Institute of Technology (US)
- European Organization for Nuclear Research (CH)
- University of Pennsylvania (US)
- The University of Texas at Austin (US)
- Universidad Nacional de La Plata (AR)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2026-04-21
- DOI
- https://doi.org/10.3847/1538-4357/ae5938
- Primary Topic
- Dark Matter and Cosmic Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Aeronautics and Space Administration
- Simons Foundation