I am primarily interested in theoretical astrophysics and cosmology, focusing on large-scale structure such as galaxy clustering, weak gravitational lensing, and cosmic microwave background. The ultimate goal of my research is to explore the dark sector of the Universe and to understand the physical mechanism of perturbation generation in the early Universe. My research involves lots of analytic and numerical computations.
Tests of General Relativity and Probes of the Early Universe: Linear Regime
On large scales, where modified gravity theories deviate from general relativity and the fingerprint of inflationary epoch remains its pristine form, the relativistic effects become important. These relativistic effects in cosmology are often ignored in the standard Newtonian description, when comparing to observations. However, we need proper relativistic descriptions of what we measure, and such relativistic effects in cosmology provide a great new opportunity to test general relativity and probe the early Universe on cosmological scales.
From Galaxies to the Dark Sector of the Universe: Nonlinear Regime
With the Sloan data, I have extensively modeled galaxy clustering and weak lensing measurements within the framework of the halo occupation distribution. Precision measurements in current surveys demand more accurate theoretical and numerical predictions, when cosmological information is extracted. Nonlinear modeling of galaxy bias and the matter fluctuation is the main topic. In addition, the relative velocity effect needs to be further constrained, before the baryonic acoustic scale can be used.
Applications to Large-Scale Galaxy Surveys: Big Data Analysis
The Institute is part of many large-scale surveys such as the Euclid Consortium, the Dark Energy Spectroscopic Instrument (DESI), the Square Kilometer Array (SKA), the LISA Consortium, and the big data set available in these surveys will provide a great opportunity to test cosmological models. However, various observational methods need to be improved and tested against numerical simulations, before its applications to real data. With unprecedented amount of data with equally unprecedented precision in these upcoming surveys, we will have lots of data to analyze, and measurements of the relativistic effects will provide exciting opportunities for discovery science.
In addition to my current research focus described above, I have worked on various other research topics:
Astrophysics:
black hole formation & dynamical evolution (astro-ph/0406217, 0702199), missing satellite problem (arXiv:0901.2116), micro-lensing for planetary constraints (astro-ph/0309302, 0403459), weak-lensing analysis for cosmological parameters and BAO peak position (astro-ph/0511580, 0901.0708), strong-lensing analysis on dark matter halos (astro-ph/0502299, 0511001), radiative transfer of the line polarization using Monte Carlo simulations (astro-ph/0112548, 0204032)
Observational Data Analysis:
proper-motion catalog of halo wide binaries to constrain MACHO fraction of our own Galaxy (astro-ph/0307437), micro-lensing light curve analysis of the OGLE and muFUN collaborations (astro-ph/0309302, 0403459), Hubble image analysis of quadruple lensed quasars (astro-ph/0502299, 0511001), HOD modeling with numerical N-body simulations (astro-ph/0511580, arXiv:0808.2988), maximum likelihood analysis of CMB lensing (arXiv:0805.2155, 1005.0847), Sloan data analysis for weak lensing and galaxy clustering (astro-ph/0511580, 0808.2988), BOSS power spectrum analysis for the BAO peak shift (arXiv:1308.1401)
latest modification: January 2023