The DREAMS Project: Disentangling the Impact of Halo-to-halo Variance and Baryonic Feedback on Milky Way Dark Matter Density Profiles
Year: 2026
Type: article
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.
Source: The Astrophysical Journal
Authors: Alex M. Garcia, Jonah C. Rose, Paul Torrey, Andrea Caputo, Mariangela Lisanti, Andrew B. Pace, Hongwan Liu, Abdelaziz Hussein, Haozhe Liu, Francisco Villaescusa-Navarro, John Barry, Ilem Leisher, Belén Costanza, Jonathan Kho, Ethan Lilie, Jiaxuan 嘉 轩 Li 李, Niusha Ahvazi, Aklant Bhowmick, Tri Nguyen, Stephanie O’Neil, Xiaowei Ou, Xuejian Shen, Arya Farahi, Nitya Kallivayalil, Lina Necib, Mark Vogelsberger
Institutions: NSF-Simons AI Institute for Cosmic Origins, University of Virginia, Princeton University, Flatiron Institute, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Fisica Nucleare, Sezione di Roma I, Weizmann Institute of Science, European Organization for Nuclear Research, Sapienza University of Rome, Boston University, Massachusetts Institute of Technology, Northeastern University, Grinnell College, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de La Plata, Northwestern University, University of Pennsylvania, The University of Texas at Austin, The NSF AI Institute for Artificial Intelligence and Fundamental Interactions, Philipps University of Marburg
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W4417025133