Search for subsolar-mass black hole binaries in the second part of Advanced LIGO's and Advanced Virgo's third observing run

Gravitational wave constraints on the primordial black hole dominated early universe

“…Most interesting for the PBH scenario is the possibility of finding evidence for planet-mass to sub-solar mass black holes, as their origin can only be primordial. And, there are potential candidates for such small PBHs in the LVK data [106][107][108][109], for sub-solar mass PBHs, and in the microlensing data of OGLE [19,20], for earth-mass PBHs (HSC [18] also reported one candidate even from a moon-mass object). One may search for such small PBHs with continuous GWs [255,263] and the GW background from unresolved binaries [84][85][86].…”

“…PBHs with masses between 0.1 M ⊙ − 100 M ⊙ may be directly detected by terrestrial GW detectors. In fact, there is the possibility that LVK may have already detected PBHs [22][23][24][25][26][106][107][108][109].…”

“…The focus of this review are GW signals of PBHs accessible to terrestrial GW detectors, which happen to include the PBH reheating scenario and PBHs with masses ranging from an earth mass to hundred solar masses. Interestingly, there are tentative hints of solar and sub-solar mass compact objects in the LVK data [106][107][108][109] and solar-mass objects in quasar broad emission lines [110]. 4 There are also the moon-mass and earth-mass microlensing events respectively reported by HSC [18] and OGLE [19,20].…”

Probing primordial black hole scenarios with terrestrial gravitational wave detectors

“…It should be noted that there will also be resolvable GWs from BH binaries (see, e.g. figure 1 of [290]), some of which could be PBH binaries [22][23][24][25][26][111][112][113][114]. There will also be a GW foreground from astrophysical binaries, which should be subtracted to probe the GW background [291].…”

“…The focus of this review is GW signals of PBHs accessible to terrestrial GW detectors, which happen to include the PBH reheating scenario and PBHs with masses ranging from an earth mass to a hundred solar masses. Interestingly, there are tentative hints of solar and subsolar mass compact objects in the LVK data [111][112][113][114] and solar-mass objects in quasar broad emission lines [115] 9 . There are also the moon-mass and earth-mass microlensing events, 7 As a curiosity, we note that if not for quantum physics (that is Hawking radiation), very light PBHs could easily eventually dominate the Universe.…”