Dissipative Dark Matter on FIRE. II. Observational Signatures and Constraints from Local Dwarf Galaxies

Creators: Shen, Xuejian; Hopkins, Philip F.¹; Necib, Lina; Jiang, Fangzhou; Boylan-Kolchin, Michael; Wetzel, Andrew

1. California Institute of Technology

Abstract

We analyze the first cosmological baryonic zoom-in simulations of galaxies in dissipative self-interacting dark matter (dSIDM). The simulations utilize the FIRE-2 galaxy formation physics with the inclusion of dissipative dark matter self-interactions modeled as a constant fractional energy dissipation (f_diss = 0.75). In this paper, we examine the properties of dwarf galaxies with M_* ∼ 10⁵–10⁹M_⊙ in both isolation and within Milky Way–mass hosts. For isolated dwarfs, we find more compact galaxy sizes and promotion of disk formation in dSIDM with (σ/m) ≤ 1 cm² g⁻¹. On the contrary, models with (σ/m) = 10 cm² g⁻¹ produce puffier stellar distributions that are in tension with the observed size–mass relation. In addition, owing to the steeper central density profiles, the subkiloparsec circular velocities of isolated dwarfs when (σ/m) ≥ 0.1 cm² g⁻¹ are enhanced by about a factor of 2, which are still consistent with the kinematic measurements of Local Group dwarfs but in tension with the H i rotation curves of more massive field dwarfs. Meanwhile, for satellites of Milky Way–mass hosts, the median circular velocity profiles are marginally affected by dSIDM physics, but dSIDM may help promote the structural diversity of dwarf satellites. The number of satellites is slightly enhanced in dSIDM, but the differences are small compared with the large host-to-host variations. In conclusion, the dSIDM models with (σ/m) ≳ 0.1 cm² g⁻¹, f_diss = 0.75 are in tension in massive dwarfs (M_halo ∼ 10¹¹M_⊙) due to circular velocity constraints. However, models with lower effective cross sections (at this halo mass/velocity scale) are still viable and can produce nontrivial observable signatures.

Copyright and License

© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

Support for X.S. and P.F.H. was provided by the National Science Foundation (NSF) Research grants 1911233, 20009234, 2108318, the NSF Faculty Early Career Development Program (CAREER) grant 1455342, the National Aeronautics and Space Administration (NASA) grants 80NSSC18K0562, HST-AR-15800. Numerical calculations were run on the supercomputer Frontera at the Texas Advanced Computing Center (TACC) under the allocations AST21010 and AST20016 supported by the NSF and TACC, and NASA HEC SMD-16-7592. F.J. is supported by the Troesh scholarship. M.B.K. acknowledges support from NSF CAREER award AST-1752913, NSF grants AST-1910346 and AST-2108962, NASA grant NNX17AG29G, and HST-AR-15006, HST-AR-15809, HST-GO-15658, HST-GO-15901, HST-GO-15902, HST-AR-16159, and HST-GO-16226 from the Space Telescope Science Institute (STScI), which is operated by AURA, Inc., under NASA contract NAS5-26555. A.W. received support from NSF grants CAREER 2045928 and 2107772; NASA Astrophysics Theory Program (ATP) grant 80NSSC20K0513; HST grants AR-15809, GO-15902, GO-16273 from STScI. This research made use of data from the SAGA Survey (https://sagasurvey.org). The SAGA Survey was supported by NSF collaborative grants AST-1517148 and AST-1517422 and by HeisingSimons Foundation grant 2019-1402.

Data Availability

The simulation data of this work was generated and stored on the supercomputing system Frontera at the Texas Advanced Computing Center (TACC), under the allocations AST20010/AST20016 supported by the NSF and TACC, and NASA HEC SMD-16-7592. The CDM FIRE-2 simulations are publicly available (Wetzel et al. 2023) at http://flathub.flatironinstitute.org/fire. However, the data of the dSIDM simulations used in this article cannot be shared publicly immediately, since the series of paper is still in development. The data will be shared on reasonable request to the corresponding author.

Files

Shen_2024_ApJ_966_131.pdf

Files (5.4 MB)

Name	Size	Download all
Shen_2024_ApJ_966_131.pdf md5:8e9021745e20816ca7622d4678477b5b	5.4 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes