Kavli Affiliate: Satoshi Shirai
| First 5 Authors: Shin’ichiro Ando, Kohei Hayashi, Shunichi Horigome, Masahiro Ibe, Satoshi Shirai
| Summary:
Self-interacting dark matter (SIDM) has been proposed to address small-scale
challenges faced by the cold dark matter (CDM) paradigm, such as the diverse
density profiles observed in dwarf galaxies. In this study, we analyze the
kinematics of dwarf galaxies by incorporating the effects of gravothermal core
collapse into SIDM models using a semi-analytical subhalo framework. Our
analysis covers the stellar kinematics of both classical and ultrafaint dwarf
galaxies. The results indicate a bimodal preference for small and large
self-interaction cross sections in ultrafaint dwarf galaxies, while in
classical dwarfs, larger cross sections progressively decrease the model’s
statistical support. The combined analysis decisively prefers CDM to SIDM when
the self-interaction cross section per unit mass, $sigma/m$, exceeds $sim$0.2
cm$^2$/g, if a velocity-independent cross section is assumed. Our study
significantly enhances our understanding of dark matter dynamics on small
scales.
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