Testing Cotton gravity as dark matter substitute with weak lensing  

作　　者：Geyu Mo Qingqing Wang Xin Ren Weitong Yan Qinxun Li Yen Chin Ong Wentao Luo 

机构地区：[1]CAS Key Laboratory for Researches in Galaxies and Cosmology,School of Astronomy and Space Science,University of Science and Technology of China,Hefei 230026,China [2]Department of Astronomy,School of Physical Sciences,University of Science and Technology of China,Hefei 230026,China [3]Department of Physics,Tokyo Institute of Technology,Tokyo 152-8551,Japan [4]Universitäts-Sternwarte,Fakultät für Physik,Ludwig-Maximilians Universität München,M¨unchen D-81679,Germany [5]Center for Gravitation and Cosmology,College of Physical Science and Technology,Yangzhou University,Yangzhou 225002,China [6]School of Aeronautics and Astronautics,Shanghai Jiao Tong University,Shanghai 200240,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2025年第4期82-90,共9页中国科学:物理学、力学、天文学(英文版)

基　　金：supported by the National Key R&D Program of China(Grant Nos.2024YFC2207500,and 2021YFC2203100);the CAS Young Interdisciplinary Innovation Team(JCTD-2022-20);the National Natural Science Foundation of China(Grant Nos.92476203,12433002,12261131497;12003029);111 Project for“Observational and Theoretical Research on Dark Matter and Dark Energy”(Grant No.B23042);the Fundamental Research Funds for Central Universities;the China Scholarship Council(CSC)Innovation Talent Funds;the University of Science and Technology of China Fellowships for International Cooperation;the University of Science and Technology of China(USTC)Research Funds of the Double FirstClass Initiative。

摘　　要：Harada proposed a modified theory of gravity called Cotton gravity,and argued that it successfully explains the rotation curves of 84 galaxies without the need for dark matter.In this work,we use the galaxy-galaxy lensing technique to test whether the modification effect of Cotton gravity can indeed be a viable substitute for dark matter.Using the spherically symmetric solution of Cotton gravity,we obtain the deflection angle via the Gauss-Bonnet theorem and the weak lensing shear.We use five galaxy catalogs divided into 5 stellar mass bins from the Sloan Digital Sky Survey Data Release 7(SDSS DR7),each further divided into blue star-forming galaxy and red passive galaxy sub-catalogs.We find that Cotton gravity on its own has a significant deviation from the measured galaxy-galaxy lensing signals,thus it cannot replace the role of dark matter.If we consider the combination of dark matter and Cotton gravity,the modification is tightly constrained.Our analysis also applies to other modified gravity theories whose an additional linear term appears in the Schwarzschild solution.

关 键 词：dark matter modified gravity gravitational lensing 

分 类 号：P145.9[天文地球—天体物理]