TY - JOUR
T1 - Formation of massive globular clusters with dark matter and its implication on dark matter annihilation
AU - Wirth, Henriette
AU - Bekki, Kenji
AU - Hayashi, Kohei
PY - 2020/5/22
Y1 - 2020/5/22
N2 - Recent observational studies of γ-ray emission from massive globular clusters (GCs) have revealed possible evidence of dark matter (DM) annihilation within GCs. It is, however, still controversial whether the emission comes from DM or from millisecond pulsars. We here present the new results of numerical simulations, which demonstrate that GCs with DM can originate from nucleated dwarfs orbiting the ancient Milky Way. The simulated stripped nuclei (i.e. GCs) have the central DM densities ranging from 0.1 to several M pc-3, depending on the orbits and the masses of the host dwarf galaxies. However, GCs born outside the central regions of their hosts can have no/little DM after their hosts are destroyed and the GCs become the Galactic halo GCs. These results suggest that only GCs originating from stellar nuclei of dwarfs can possibly have DM. We further calculate the expected γ-ray emission from these simulated GCs and compare them to observations of ω Cen. Given the large range of DM densities in the simulated GCs, we suggest that the recent possible detection of DM annihilation from GCs should be more carefully interpreted.
AB - Recent observational studies of γ-ray emission from massive globular clusters (GCs) have revealed possible evidence of dark matter (DM) annihilation within GCs. It is, however, still controversial whether the emission comes from DM or from millisecond pulsars. We here present the new results of numerical simulations, which demonstrate that GCs with DM can originate from nucleated dwarfs orbiting the ancient Milky Way. The simulated stripped nuclei (i.e. GCs) have the central DM densities ranging from 0.1 to several M pc-3, depending on the orbits and the masses of the host dwarf galaxies. However, GCs born outside the central regions of their hosts can have no/little DM after their hosts are destroyed and the GCs become the Galactic halo GCs. These results suggest that only GCs originating from stellar nuclei of dwarfs can possibly have DM. We further calculate the expected γ-ray emission from these simulated GCs and compare them to observations of ω Cen. Given the large range of DM densities in the simulated GCs, we suggest that the recent possible detection of DM annihilation from GCs should be more carefully interpreted.
KW - dark matter
KW - globular clusters: general
KW - globular clusters: individual: Omega Centauri
UR - http://www.scopus.com/inward/record.url?scp=85087005836&partnerID=8YFLogxK
U2 - 10.1093/mnrasl/slaa089
DO - 10.1093/mnrasl/slaa089
M3 - Article
AN - SCOPUS:85087005836
SN - 1745-3925
VL - 496
SP - L70-L74
JO - Monthly Notices of the Royal Astronomical Society: Letters
JF - Monthly Notices of the Royal Astronomical Society: Letters
IS - 1
ER -