Remnants of first stars for gravitational wave sources: Dr. Tomoya KINUGAWA (ICRR)

ICRR Seminar

 Date&Time October 9, 2020 15:30-17:00
 Place  ZOOM
 Speaker  Dr. Tomoya KINUGAWA (ICRR)  
 Title“Remnants of first stars for gravitational wave sources”
Abstract Using our population synthesis code, we found that the typical chirp mass of binary black holes (BH-BHs) whose origin is the first star (Pop III) is ∼30M⊙ with the total mass of ∼60M⊙ so that the inspiral chirp signal as well as quasi normal mode (QNM) of the merging black hole are interesting targets of LIGO,VIRGO, and KAGRA (Kinugawa et al.2014 and 2016). The detection rate of the coalescing Pop III BH-BHs is ∼180 events/yr in our standard model. Furthermore, we found that the chirp mass has a peak at ∼30M⊙ in most of parameters and distribution functions (Kinugawa et al.2016). This result predicted the gravitational wave events like GW150914 and LIGO paper said “recently predicted BBH total masses agree astonishingly well with GW150914 and can have sufficiently long merger times to occur in the nearby universe (Kinugawa et al. 2014)” (Abbot et al. ApJL 818,22 (2016)). There is a good chance to check indirectly the existence of Pop III massive stars by gravitational waves. Furthermore, we can simultaneously explain the formation of binaries that consist of a BH and mass gap compact object (MGCO) with mass 2-5 M⊙ (Kinugawa et al.2020) like GW190814, and those consist of BHs with mass ∼80M⊙ within the PISN mass gap for Pop III stars like GW190521. It is very interesting that Pop III model can interpret origins of three different class of GW sources, that is, massive BH binary of mass 30Msun like GW150914, BH and MGCO of mass 2.5M⊙ like GW190814, and very massive binary BH of 80M⊙ like GW190521. It will be triple the fun!