Searching for dark dressed primordial black hole binaries in space-based gravitational-wave detectors

Primordial black holes (PBHs) could have formed in the early universe, and if they did, could constitute a portion or all of dark matter. A priori, PBHs could take on any mass that depends on when they formed; thus, many experiments have been designed to probe particular mass regimes of PBHs, ranging from O(10−18 −103)M⊙ . Ground-based GW detectors can be sensitive to binary PBHs that inspiral and merge roughly between [10−9,103]M⊙ ; however, systems below a solar mass could spend hours or even longer in the detector frequency band. Such long-lived signals imply that many more templates are needed to populate a given parameter space compared to short-lived ones, since phase mismatches between templates accumulate with signal duration. Thus, it requires a lot more computing power to correlate this large number of templates with the data. To ensure an analysis is computationally tractable, we have developed a method to track the frequency evolution of inspiraling planetary-mass PBH binaries over time, but have only considered the simplest case: that is, equal-mass, quasi-Newtonian, non-spinning objects. Recently, we have also considered that 10−3M⊙ exotic object, e.g. a PBH, could orbit around a [10,100]M⊙ one, a so-called “mini” extreme-mass ratio inspiral, and have added relativistic effects to the quasi-Newtonian waveform and assessed whether our methods could be still be sensitive to this source. In this project, the student will consider the possibility that dark matter clouds exist around primordial black holes in the context of future gravitational-wave missions, such as LISA and Einstein Telescope. The student will explore the impact of dynamical friction on the evolution of the binary across all binary black hole masses that could be seen, as well as other mechanisms to produce dark matter around black holes, and how this could impact the detection of such systems.