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zhafen / linefinder

A tool for finding and classifying the worldlines of Lagrangian parcels of mass, in the context of hydrodynamic simulations of galaxy formation.
https://zhafen.github.io/linefinder
MIT License
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A lot of stars form well outside the effective radius #63

Closed zhafen closed 6 years ago

zhafen commented 6 years ago

Originally reported by Zachary Hafen (Bitbucket: zhafen, GitHub: zhafen)

Potential causes:

  1. The effective radius is wrong
  2. I'm loading the effective radius incorrectly
  3. This is from very early redshift where the effective radius is quite small.

Investigative steps:

  1. Plot the effective radius as a function of redshift.
  2. Plot the stellar effective radii used for scaling.
zhafen commented 6 years ago

Original comment by Zachary Hafen (Bitbucket: zhafen, GitHub: zhafen)

re Issue #63, I fixed the most egregious error, where data wasn't being copied, and as aresult was growing larger and larger.

zhafen commented 6 years ago

Original comment by Zachary Hafen (Bitbucket: zhafen, GitHub: zhafen)

The remaining difference seems to be from a combination of two things:

  1. Particles that are ejected from the main galaxy and then go on to form stars.
  2. Particles that never form stars, and are therefore not properly masked.

I think we're good to close this issue.

zhafen commented 6 years ago

Original comment by Zachary Hafen (Bitbucket: zhafen, GitHub: zhafen)

Okay, so this is largely fixed, but... There are still a large number of stars that appear to form well outside the stellar effective radius, but not close to another galaxy. See below plot.

rstar_vs_ralt_in_rhalf.png

zhafen commented 6 years ago

Original comment by Zachary Hafen (Bitbucket: zhafen, GitHub: zhafen)

Figured out a bit of what's going on... It seems like I'm not making copies of the data somewhere.

zhafen commented 6 years ago

Original comment by Zachary Hafen (Bitbucket: zhafen, GitHub: zhafen)

Checked option 3, and it's better at low redshift, but there are still a lot of values with Rhalf<1...

zhafen commented 6 years ago

Original comment by Zachary Hafen (Bitbucket: zhafen, GitHub: zhafen)

Here's the plot for stellar effective radii. Damn, are those values small. This is clearly wrong.

rhalf_vs_rtstar.png

zhafen commented 6 years ago

Original comment by Zachary Hafen (Bitbucket: zhafen, GitHub: zhafen)

I plotted the stellar effective radius along with FIRE-1 m12i's stellar effective radius, and they're quite comparable. They diverge only at the end, and at that point Rstar0.5(m12i) = 3 kpc, as opposed to Rstar0.5(m12iF1) = 4kpc.