http://arxiv.org/abs/2108.01102
It has been a mystery how the diffuse dwarf galaxies that are deficient in dark matter — such as NGC1052DF2 and NGC1052-DF4 — have formed. Along with their luminous member globular clusters (GCs), the so-called dark matter deficient galaxies (DMDGs) have challenged observers and theorists alike. Here we report a suite of galaxy collision simulations using the adaptive mesh refinement code ENZO with 1.25 pc resolution, which demonstrates that high-velocity galaxy collisions induce the formation of DMDGs and their star clusters (SCs) simultaneously. With numerical resolution significantly better than our previous study (80 pc in Shin et al. 2020), we resolve the dynamical structure of the produced DMDGs and the detailed formation history of their SCs which are possible progenitors of the DMDG’s member GCs. In particular, we show that a galaxy collision with a high relative velocity of $\sim 300\;{\rm km\;s}^{-1}$, invoking severe shock compression, spawns multiple massive SCs ($\gtrsim 10^{6}\;{\rm M}{\odot}$) within 150 Myr after the collision. At the end of our ~ 800 Myr fiducial run, the resulting DMDG of $M{\star} \simeq 3.5\times 10^{8}\;{\rm M}{\odot}$ hosts 10 luminous ($M{\rm V} \lesssim -8.5\;{\rm mag}$), gravitational bound SCs with a line-of-sight velocity dispersion $11.2\;{\rm km\;s}^{-1}$. Our study suggests that DMDGs and their luminous member SCs could form simultaneously in high-velocity galaxy collisions while being in line with the key observed properties of NGC1052-DF2 and NGC1052-DF4.
J. Lee, E. Shin and J. Kim
Wed, 4 Aug 21
43/66
Comments: 10 pages including 6 figures. Accepted for publication in ApJL. For associated movies and information, see this http URL, this http URL and this http URL