Indirect Evidence for Dark Matter Density Spikes around Stellar-Mass Black Holes

Understand

It has been suggested for a long time that dark matter would form a density spike around a black hole.

• However, no promising evidence has been observed so far to verify this theoretical suggestion.
• Here, we report the existence of a dark matter density spike around each of the two nearby stellar-mass black holes (A0620-00 and XTE J1118+480).
• The dynamical friction between dark matter and the companion stars can satisfactorily explain the abnormally fast orbital decays in the two binaries.