English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Recently, advanced Laser Interferometer Gravitational-Wave Observatory(aLIGO) has detected black hole (BH) merger events, most of which are sourcedby BHs more massive than $30~M_\odot$. Especially, the observation of GW170104suggests dynamically assembled binaries favoring a distribution of misalignedspins. It has been argued that mergers of unassociated BHs can be engenderedthrough a "chance meeting" in a multiple BH system under gas-rich environments.In this paper, we consider the merger of unassociated BHs, concordant with themassive BH merger events. To that end, we simulate a multiple BH system with apost-Newtonian $N$-body code incorporating gas accretion and generalrelativistic effects. As a result, we find that gas dynamical frictioneffectively promotes three-body interaction of BHs in dense gas of$n_\mathrm{gas}\gtrsim 10^6\,\mathrm{cm}^{-3}$, so that BH mergers can takeplace within $30$ Myr. This scenario predicts an isotropic distribution of spintilts. In the concordant models with GW150914, the masses of seed BHs arerequired to be $\gtrsim 25~M_\odot$. The potential sites of such "chancemeeting" BH mergers are active galactic nucleus (AGN) disks and denseinterstellar clouds. Assuming the LIGO O1, we roughly estimate the event ratesfor PopI BHs and PopIII BHs in AGN disks to be respectively $\simeq1-2\,\mathrm{yr}^{-1}$ and $\simeq 1\,\mathrm{yr}^{-1}$. Multiple episodes ofAGNs may enhance the rates by roughly an order of magnitude. For massive PopIBHs in dense interstellar clouds, the rate is $\simeq 0.02\,\mathrm{yr}^{-1}$.Hence, high-density AGN disks are a more plausible site for mergers of chancemeeting BHs.

Merger of multiple accreting black holes concordant with gravitational wave events