CPLUOS Astrophysics team meeting

Friday 19 Aug 2022, 14:00 → 15:35 Asia/Seoul

물리학과

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

14:00 → 15:10 COSMOLOGY

14:00 Hyeonmo's Report

Speaker: Hyeonmo Koo (University of Seoul)

Brief Introduction of the Calculation inside GADGET2 Simulation & Plotting

• No progress

14:10 Young's report. FoF and MST algorithm

Speaker: Young Ju

FoF and MST algorithm (Writing a paper)

• Mulguisin Clustering Algorithm I. - Comparison of Clustering Algorithms for Study of Cosmic Structure Finding

14:20 Hannah's Report

See the slides from 8p

Speaker: Hannah Jhee (University of Seoul)

Axionyx: CDM Mixed Simulation

• True phase-space trajectories

14:30 Seyeon's Report - CLML

Speaker: Se Yeon Hwang (Universe of Seoul)

Cosmology with Large scale structure using Machine Learning (CLML)

• Blue print
  • Pinocchio (= dark matter halo simulation)
  • Snapshot (fixed z) → In Spring KAS → CNN
  • Light cone (..< z <..) → In IAU → CNN and ViT
  • Light cone (..< z <..) → In Future → Make galaxy catalog → CNN and ViT
  • What we have to solve before going next step is..
  • Getting good result on using light cone data!!
• Outline
  • Problem
    • ViT result with augmentation
      • It is difficult to say why only O_m and w₀ have some signal on Vit.
      • We are considering about changing input data which using light cone (not yet...).
      • Today: We checked our first result in KAS
    • Our parameter space:
      • 0.16 ≤ Ω_m ≤ 0.46
      • 0.4 ≤ σ₈ ≤  1.1
      • (Box size, Number of particles)
        • (512 (Mpc), 512³)
      • Other parameters
        • (Ω_baryon, h, n_s, w0, wa)
        • (0.0493, 0.6736, 0.9649, -1, 0)
      • In Ω_m - σ₈ graph,
        • I used latin hypercube sampling
      • Snapshot data (0 ~ 64 Mpc), bin size = 32, one pixel has 2 Mpc information
      • Learning rate = 0.0005
      • Epoch = 150
      • Snapshot data (0 ~ 512 Mpc), bin size = 32, 64 times larger than above one
        • Black
        • Green
• IAU feedback
  • 1. About histogram resolution
  • 2. Parameter >> Gaussian distribution

14:40 Sumi's report

Speaker: Sumi Kim (University of Seoul)

Calculating Bright Galaxy Survey (BGS) 2 pcf

• Examples of how to run Barry for DESI KP4

14:50 In's Report

Speaker: In Hwang (University of Seoul)

Kerr Black Hole Mechanics using EinsteinPy

• Visualizing Ergosphere and Event Horizon and Singularities of Kerr Metric or Black Hole
• Visualizing Frame-dragging in Kerr Space-time
• Future work
  • Try making some more black hole plots using EinsteinPy.
  • The Hawking temperature determines the mass of the black hole, and the mass of the black hole determines the evaporation time of the black hole.
  • Find the masses of the black holes when the evaporation time of the black holes is Planck time.
  • This condition means the initial masses of the black holes where the effects of quantum gravity can appear.
  • Here, the final masses of the black holes are zero. The reason is that Hawking radiation reduces mass.

15:00 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

15:10 → 15:20 Discussion