May 15 – 17, 2026
College of Hakka Studies at NYCU, Zhubei, Hsinchu County 國立陽明交通大學客家學院(竹北六家校區)
Asia/Taipei timezone

Gravitational Lensing with an Elliptical Halo Model

Not scheduled
15m
College of Hakka Studies at NYCU, Zhubei, Hsinchu County 國立陽明交通大學客家學院(竹北六家校區)

College of Hakka Studies at NYCU, Zhubei, Hsinchu County 國立陽明交通大學客家學院(竹北六家校區)

No. 1, Sec. 1, Liujia 5th Rd., Zhubei City, Hsinchu County 302, Taiwan 30272新竹縣竹北市六家五路一段1號
Board: 40

Speaker

Ya-I Chen (National Yang Ming Chiao Tung University)

Description

In this study, we investigate the gravitational lensing effects of projected elliptical halos. We perform a comparative analysis of the Cored Steep Ellipsoid (CSE) model, the standard spherical NFW model, and the elliptical NFW model to assess their relative performance and accuracy.
Within the CSE framework, we conduct a quadrupole shear analysis and further extend it to include higher order shear components. Our results show that quadrupole shear analysis often leads to bimodal degeneracies in the position angle (PA) constraints when shape noise is taken into account. In contrast, incorporating higher order shear components significantly improves the constraints on the PA measurement.
Furthermore, the efficient implementation of the CSE approximation provides a robust foundation for cluster forward-modeling applications. Using simulation-based inference (SBI), we demonstrate the model performance and its ability to constrain posterior distributions of key parameters. This approach offers a promising pathway for constraining the projected ellipticity of galaxy cluster samples detected in large sky surveys.

Participate the oral/poster presentation award competition Yes

Author

Ya-I Chen (National Yang Ming Chiao Tung University)

Presentation materials

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