I couldn't help but notice how similar DF2 is to the nearby Sagittarius dwarf
[A thread; 1/N]
The Sagittarius dwarf (Sag) is a nearby galaxy, first discovered by Ibata et al. in 1995, that we know is currently being torn apart by tidal forces from the Milky Way.
There is a growing consensus in the astro simulation community that, once we begin to resolve the interstellar medium (ISM), gas cooling and heating causes gravitational potential fluctuations that kinematically "heat up" dark matter [a thread 1/N]
If we can get the gravitational potential to fluctuate "significantly" on a timescale comparable to the local dynamical time, then dark matter (DM) is "heated up":
For a Twitter summary of the results, please read on ... [1/N]
Jun 15, 2018 • 10 tweets • 2 min read
This recent press release on some of the latest galaxy formation simulations has reignited an old debate about dark matter versus modified theories of gravity. Sadly, many commentators seem to be missing the point. (A thread, 1/N.)
quantamagazine.org/coder-physicis…
In mod. grav. theories, all the force comes from the visible stars & gas. Given good observations, we can accurately predict the gravitational force field without knowing the first thing about how galaxies form. Such theories are easy to test in disc galaxies & work well. (2/N.)
