MOCCA-SURVEY Database -- I. Tidal disruption events of white dwarfs in globular clusters and young massive clusters

Abstract

We investigate more than 1000 star cluster models (about half of all the cluster models in MOCCA-Survey Database I), and obtain the local rate density of white dwarf (WD) tidal disruption events (TDEs) in globular clusters (GCs) and young massive clusters (YMCs). We find that WD TDEs in a star cluster happen 1000 times more efficiently than predicted previously. We take into account WD TDEs in GCs, YMCs, and dwarf galaxies, and obtain the total WD TDE rate density in the local universe as ∼ 5.0 × 10 2 yr −1 Gpc −3 , 90 % of which happens in GCs. The total WD TDE rate density is 50 times larger than estimated before. Our results show that thermonuclear explosions induced by WD TDEs can be observed at a rate of 550 yr −1 by the next generation optical surveys, such as the Large Synoptic Survey Telescope. We also find that massive WDs are preferentially disrupted due to mass segregation, and that 20 % of exploding WDs have 1.0𝑀 despite of small population of such WDs. Such explosions can be as luminous and long as type Ia supernovae (SNe Ia), in contrast to previous arguments that such explosions are observed as more rapid and faint transients than SNe Ia due to their small radioactive mass ( 0.1𝑀 ) and ejecta mass ( 0.6𝑀 ).

Extragalactic fast X-ray transient candidates discovered byChandra(2000–2014)

“…LGRBs LL − LGRBs SGRBs (Sun et al 2015) but not with IMBH-WD TDEs (Tanikawa et al 2021), likely due to the different progenitor system.…”

“…6.3). As a comparison, we also plot the local event rate of CDF-S XT2-like events (purple square;Xue et al 2019), GW 170817 (green square;Abbott et al 2017b), and GRB 170817A (magenta square;Zhang et al 2018), as well other kinds of transients, such as the new SBO candidate in XMM-Newton data (yellow square and circle;Xu et al 2008;Novara et al 2020), the TDE rate of SMBH-MS TDEs (black triangle;Sun et al 2015) and the IMBH-WD TDE rate (orange triangle and circle;Malyali et al 2019;Tanikawa et al 2021), the CC-SN rate (magenta triangle), the merger rate of BNS systems (light green circle;Abbott et al 2021c), and the merger rate of neutron star and BH systems (gray circles;Abbott et al 2021b). The local event rate of LGRBs, LL-LGRBs, and SGRBs are plotted (blue, green, and red horizontal shaded regions, corrected for the jet aperture factor; Zhang 2018).…”

Extragalactic fast X-ray transient candidates discovered by Chandra (2000-2014)

“…The latter may simply be a consequence of the f (z) assumption. Moreover, the TDE local density rate of FXRT 8/9/13 (ρ TDEs 0,FXRT 8/9/13 ) remains consistent with SMBH-MS TDE rates (Sun et al 2015) but not with IMBH-WD TDEs (Tanikawa et al 2021) likely due to the different progenitor system. 6.4.…”

Formation of supermassive black holes in galactic nuclei – I. Delivering seed intermediate-mass black holes in massive stellar clusters

“…The scenarios involving massive stars would require the presence of young newly formed stars in the NSC. Additionally, growth of stellar-mass BHs and low-mass IMBH from the tidal capture and disruption of stars is most likely to occur in NSCs with central densities larger than few 10 6 M (Stone et al 2017;Tanikawa et al 2021). For dense stellar systems with high central velocity dispersion values (larger than 50 km s −1 ), binary-single interactions will be unable to heat the cluster and prevent core collapse.…”