White dwarf-white dwarf collision in AGN disks via close encounters
Luo, Yan
The AGN are believed to hold a large population of white dwarfs. Those white dwarfs will align into the disks and migrate toward the inner disks, and form restricted three-body systems with two white dwarfs around central SMBH. Such systems could be dynamical unstable, which can lead to chaotic evolution and very close encounters. We perform a set of simulations to study the evolution of such systems with different initial parameters: initial orbital separation, relative orbital inclinations and different central SMBH mass. We find that most of such systems can occur WD-WD collisions during the close encounters, but the collision fraction will be affected by the inclination and central SMBH mass. If all collisions can lead to type I SNe, e estimate a collision rate of such systems in AGN disks ~300/(Gpc^3 yr). The corresponding electricmagnetic emission signals can be observed by large survey of AGNs.