Visualizations

Dark Matter Deficient Galaxies Produced Via High-velocity Galaxy Collisions In Numerical Simulations

Shin, E. -J., Jung, M., Kwon, G., Kim, J. -H., Lee, J., Jo, Y., & Oh, B. K.

We implement the numerical experiments to determine if the so-called dark matter deficient galaxies (DMDGs) could be produced when two gas-rich, dwarf-sized galaxies collide with a high relative velocity of ∼ 300 kms−1. Using idealized high-resolution simulations with both mesh-based and particle-based gravito-hydrodynamics codes, we find that DMDGs can form as high-velocity galaxy collisions separate dark matter from the warm disk gas which subsequently is compressed by shock and tidal interaction to form stars. For details, see our paper.

Click to see the high-resolution image.

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An idealized galaxy collision simulation on GADGET-2 demonstrating the “collision-induced” DMDG formation scenario. The high-velocity (∼ 300kms−1) collision of two gas-rich, dwarf satellite galaxies near a massive host produces multiple DMDGs. [Movie]

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Idealized galaxy collision simulation on the grid-based code ENZO. The most massive DMDG is with Mstar, <5kpc = 1.60 × 108M⊙ [Movie]

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Left: the star formation rate (SFR) within 20 kpc from the most massive DMDG born in the ENZO simulation. Middle: the radial profile of the enclosed mass in the most massive DMDG at t = 870 Myr, showing that little dark matter exists in the DMDG. Right: 2-dimensional probability distribution function (PDF) of density and temperature for the gas within 20 kpc from the center of the most massive DMDG at t = 420 Myr.

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Same as above, but the results from the particle-based code GADGET-2. The most massive DMDG is with Mstar, <5kpc = 2.16 × 108 M⊙. [Movie]

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Same as above, but the results from the particle-based code GADGET-2.