Speaker
Description
The discovery of subsolar mass black holes would provide compelling evidence
for the primordial origin of these objects. In this talk, I explore
how gravitational wave (GW) signals from a Galactic population of (sub)solar
mass primordial black hole (PBH) binaries could be identified by LISA (arXiv:
2410.04522). By modeling the formation and evolution of PBH binaries that
end up in the Milky Way halo at the present epoch, we find that their highly
eccentric orbits generate a GW background that peaks in the millihertz range,
where LISA’s sensitivity is optimal. While this background is below LISA’s
detection threshold for PBH fractions of 1% of dark matter, it exceeds the detection
limits of DECIGO and BBO for PBH masses of order 0.01-0.1 solar mass.
Additionally, in five years of observation LISA could identify up to O(100) loud
Galactic PBH binaries in the (sub)solar mass range for a PBH fraction of 1%,
or O(1) for a fraction of 0.1%.
