CPLUOS Astrophysics team meeting

Friday 8 Jul 2022, 14:00 → 15:10 Asia/Seoul

물리학과

https://uos-ac-kr.zoom.us/j/8264902652

COSMOLOGY¶

1 Hyeonmo's Report¶

Speaker: Hyeonmo Koo (University of Seoul)

Brief Introduction of the Calculation inside GADGET2 Simulation & Plotting

• Smoothing length h_i would be decided from: N (0 < r < 2h_i) = 30.
  • Number of particles inside r < 2h_i graph
  • ρ_Calculated - ρ_Data
• Number of particles per each halo = 20000 → x 50 collision samples → Superposition → Number of particles per each halo = 1000000 → N (0 < r < 2h_i) can be roughly given as 30 x 50 = 1500
  • pynbody.config['sph']['smooth-particles'] = 1500 ≈ 1200
• Displacement 5 pc → Superposition
• Used vi_render.pyx
• Initial → (O)
• Statistical → (X)
• One grid size: 170 pc
• Solve for how many sigma differences.

2 Young's report. FoF and MST algorithm¶

Speaker: Young Ju

FoF and MST Algorithm

• Comparison of density calculation
  • MGS calculates density before finding neighbors.
    • Density threshold : 10 Mpc/h
    • Density threshold : 5 Mpc/h
    • Using Voronoi method
    • No kink
• MGS for python version
  • Use 'Numba', it takes about 2 minutes.
  • C++ code → Python code
  • Loop three times → Loop once
• We need the optimization.

3 Hannah's Report¶

See the slides from 8p

Speaker: Hannah Jhee (University of Seoul)

Axionyx

• Test on multi-level grids
• Possible caveats
  • Initial soliton profile
  • Boundary condition: Outflow?
  • Periodic boundary condition (X)
  • → Free streaming
  • → Good boundary condition
  • → Halo condition simulation
  • Give plenty of time → Relaxation
  • r_1/2 → Fixed
  • r₀ → Random
  • Halo has zero centroid velocity and is at rest.

4 Sumi's report¶

Speaker: Sumi Kim (University of Seoul)

Plan for IAU Poster

• No progress

5 Dr.Sabiu's Report¶

Speaker: Dr Cristiano Sabiu (University of Seoul)

Deep Learning the Deep Sky: Recovering Low Surface Brightness Objects with Machine Learning

• No progress

6 Discussion¶