摘要
The observed rotation curves of low surface brightness(LSB)galaxies play an essential role in studying dark matter,and indicate the existence of a central constant density dark matter core.However,the cosmological N-body simulations of cold dark matter predict an inner cusped halo with a power-law mass density distribution,and cannot reproduce a central constant-density core.This phenomenon is called cusp-core problem.When dark matter is quiescent and satisfies the condition for hydrostatic equilibrium,the equation of state can be adopted to obtain the density profile in the static and spherically symmetric space-time.To address the cusp-core problem,we assume that the equation of state is independent of the scaling transformation.Its lower order approximation for this type of equation of state can naturally lead to a special case,i.e.,■,where p andρrepresent the pressure and density,respectively,V_(rot) depicts the rotation velocity of galaxy,andζandεare positive constants.It can obtain a density profile that is similar to the pseudo-isothermal halo model whenεis approximately 0.15.To obtain a more universally used model,let the equation of state include the polytropic model,i.e.■,from which we can obtain other types of density profiles,such as the profile that is nearly same as the Burkert profile,where s and ρ_(0) are positive constants.
作者
Xiaobo Gong
Meirong Tang
Zhaoyi Xu
龚小波;唐美荣;徐兆意(Yunnan Observatories,Chinese Academy of Sciences,Kunming,650216,China;Key Laboratory for the Structure and Evolution of Celestial Objects,Chinese Academy of Sciences,Kunming 650216,China;Center for Astronomical Mega-Science,Chinese Academy of Sciences,Beijing 100012,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Particle Astrophysics,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China)
基金
Supported by the National Natural Science Foundation(NSF)of China(11973081,11573062,11403092,11390374,11521303)
the YIPACAS Foundation(2012048)
the Chinese Academy of Sciences(CAS,KJZD-EW-M06-01)
the NSF of Yunnan Province(2019FB006)
the Youth Project of Western Light of CAS。
