Dark-Matter-Deficient Galaxies from Collisions: A New Probe of Bursty Feedback and Dark Matter Physics

Abstract

High-velocity collisions between gas-rich ultra-diffuse galaxies present a promising formation channel for dark-matter-deficient galaxies (DMDGs). Using hydrodynamical simulations, we show that the progenitors' baryonic binding energy, $|E_{\mathrm{bind}}|$, critically controls the outcome. Repeated potential fluctuations, e.g., from bursty feedback, inject energy and reduce $|E_{\mathrm{bind}}|$ by $\approx 15\%$, yielding fewer but substantially more massive DMDGs. By contrast, elastic self-interacting dark matter (SIDM) produces comparable cores without lowering $|E_{\mathrm{bind}}|$, perturbing DMDG masses without clear enhancement. This differs from what happens in host halos, where SIDM-induced cores enhance dark matter tidal stripping while keeping baryons compact and resilient to tidal effects. The contrasting roles of SIDM may provide a means to distinguish feedback-formed halo cores from those created by SIDM. Among 15 paired simulation runs, 13 show higher DMDG masses in the weakened-binding case, and about two thirds exhibit $>100\%$ mass enhancements. The simulations also predict systematically lower gas fractions due to sustained post-collision star formation, yielding a clean observational signature. Upcoming wide-field imaging (CSST, LSST), HI surveys (FAST), and kinematic follow-up will be crucial to test this scenario.

16 pages, 11 figures. Extended for distinguishing cores from SIDM vs. stellar feedback. Matches the accepted version by ApJL

References in corpus (27)

• Simulating cosmic structure formation with the GADGET-4 code
• Cosmological puzzle resolved by stellar feedback in high redshift galaxies
• NIHAO XI: Formation of Ultra-Diffuse Galaxies by outflows
• A second galaxy missing dark matter in the NGC1052 group
• From Tidal Dwarf Galaxies to Satellite Galaxies
• Tidal dwarf galaxies as a test of fundamental physics
• The abundance of ultra-diffuse galaxies from groups to clusters: UDGs are relatively more common in more massive haloes
• A Portrait of Cold Gas in Galaxies at 60pc Resolution and a Simple Method to Test Hypotheses That Link Small-Scale ISM Structure to Galaxy-Scale Processes
• Robust HI kinematics of gas-rich ultra-diffuse galaxies: hints of a weak-feedback formation scenario
• A trail of dark matter-free galaxies from a bullet dwarf collision
• Galaxies lacking dark matter produced by close encounters in a cosmological simulation
• Gravothermal evolution of dark matter halos with differential elastic scattering
• Dark Matter Deficient Galaxies Produced Via High-velocity Galaxy Collisions In High-resolution Numerical Simulations
• The massive relic galaxy NGC 1277 is dark matter deficient. From dynamical models of integral-field stellar kinematics out to five effective radii
• Strong Dark Matter Self-interactions Diversify Halo Populations within and surrounding the Milky Way
• Self-Interacting Dark Matter and the Origin of Ultra-Diffuse Galaxies NGC1052-DF2 and -DF4
• The Odd Dark Matter Halos of Isolated Gas-rich Ultradiffuse Galaxies
• RIGEL: Simulating dwarf galaxies at solar mass resolution with radiative transfer and feedback from individual massive stars
• Recurrent Axinovae and their Cosmological Constraints
• Chemodynamic evolution of dwarf galaxies in tidal fields
• Multiple Beads-on-a-string: Dark Matter-Deficient Galaxy Formation in a Mini-bullet Satellite-satellite Galaxy Collision
• The Response of Dark Matter Haloes to Gas Ejection: CuspCore II
• Mass models of gas-rich void dwarf galaxies
• Kinematic signatures of impulsive supernova feedback in dwarf galaxies
• Dark Matter-Induced Baryonic Feedback in Galaxies
• Detection and characterization of detached tidal dwarf galaxies
• Head-on collisions of fuzzy/cold dark matter subhalos