Posts by Collection

CUBE – Towards an Optimal Scaling of Cosmological N-body Simulations

Published in IEEE conference, 2020

We designed a two-level PM algorithm CUBE towards optimal performance in memory consumption reduction. By using the fixed-point compression technique, CUBE reduces the memory consumption per N-body particle to only 6 bytes, an order of magnitude lower than the traditional PM-based algorithms.

Recommended citation: Shenggan Cheng, Hao-Ran Yu, Derek Inman, Qiucheng Liao, Qiaoya Wu and James Lin (2020, May). CUBE–Towards an Optimal Scaling of Cosmological N-body Simulations. In 2020 20th IEEE/ACM International Symposium on Cluster, Cloud and Internet Computing (CCGRID) (pp. 685-690). IEEE. https://ieeexplore.ieee.org/abstract/document/9139651

Spin mode reconstruction in Lagrangian space

Published in Physical Review D, 2021

We define a Lagrangian spin parameter and tidal twist parameters and quantify their influence on the spin conservation and predictability in the spin mode reconstruction in N-body simulations. We conclude that protohalos in more tidal twisting environments are preferentially more rotation-supported, and more likely to conserve their spin direction through the cosmic evolution. These tidal environments and spin magnitudes are predictable by a density reconstruction in Lagrangian space, and such predictions can improve the correlation between galaxy spins and the initial conditions in the study of constraining the primordial universe by spin mode reconstruction.

Recommended citation: Qiaoya Wu, Hao-Ran Yu, Shihong Liao, Min Du (2021). Spin mode reconstruction in Lagrangian space. Physical Review D, 103(6), 063522. https://journals.aps.org/prd/abstract/10.1103/PhysRevD.103.063522

The Disk Veiling Effect of the Black Hole Low-mass X-Ray Binary A0620-00*

Published in ApJ, 2022

Here in this work, we carry out a strictly simultaneous spectroscopic and photometric campaign on the prototype of black hole low-mass X-ray binary A0620-00. We find that for each observation epoch, the extra optical flux beyond a pure ellipsoidal modulation is positively correlated with the fraction of veiling emission, indicating the accretion disk contributes most of the nonellipsoidal variations. Meanwhile, we also obtain a K2V spectral classification of the companion, as well as the measurements of the companion’s rotational velocity $v\sin i = 83.9\pm 1.9$ km s$^{-1}$ and the mass ratio between the companion and the black hole $q = 0.063 ± 0.004$.

Recommended citation: Zheng, W. M., Wu, Q., Wu, J., Wang, S., Sun, M., Guo, J., ... & Reynolds, M. T. (2022). The Disk Veiling Effect of the Black Hole Low-mass X-Ray Binary A0620-00. The Astrophysical Journal, 925(1), 83. https://iopscience.iop.org/article/10.3847/1538-4357/ac4332

Cosmological N-body simulations & Dark matter halo angular momentum

Published: November 30, 2019

The large scale structure (LSS) of the Universe contains plenty of cosmological information. One of the most important task of LSS studies is to use the distribution of galaxies to interpret the initial conditions of the Universe and cosmological parameters. To investiagate the inner relations between the early universe and current LSS, we use cosmological N-body simulation code CUBE to study the angular momentum of dark matter halos in $z=0$ and initial conditions.

Correlations between halo spins and primordial perturbations

Published: May 14, 2021

This work based on my paper “spin mode reconstruction in Lagrangian space” published in Physical Review D in 2021. This work was supervised by Prof. Haoran Yu in Xiamen University, and collaborated with 2 postdocs Dr. Shihong Liao and Dr. Min Du. Poster can be found here