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Abstract We study the stellar distribution around supermassive black holes in gas-rich nuclear star clusters (NSCs). NSCs could contain vast amounts of gas, which contribute significantly to shaping the stellar distribution, typically altering the stellar density cusp from the usual J. N. Bahcall & R. A. Wolf solution and consequently affecting the dynamics in the NSC. The dense gaseous environment in NSCs gives rise to dynamical phenomena that are otherwise rare in other gas-free environments. Here we extend the derivation introduced in J. N. Bahcall & R. A. Wolf to include an additional energy dissipation term associated with gas drag. We examine the effects of different forms of gas drag on the stellar density distribution. Finally, we discuss implications on the rates of tidal disruption events and other transients triggered by stellar interactions in gas-rich galactic nuclei. 

Abstract Black hole–neutron star binaries are of interest in many ways: they are intrinsically transient, radiate gravitational waves detectable by LIGO, and may produceγ-ray bursts. Although it has long been assumed that their late-stage orbital evolution is driven entirely by gravitational wave emission, we show here that in certain circumstances, mass transfer from the neutron star onto the black hole can both alter the binary's orbital evolution and significantly reduce the neutron star's mass: when the fraction of its mass transferred per orbit is ≳10⁻², the neutron star's mass diminishes by order unity, leading to mergers in which the neutron star mass is exceptionally small. The mass transfer creates a gas disk around the black holebeforemerger that can be comparable in mass to the debris remaining after merger, i.e., ~0.1M_⊙. These processes are most important when the initial neutron star–black hole mass ratioqis in the range ≈0.2–0.8, the orbital semimajor axis is 40 ≲ a₀/r_g ≲ 300 (r_g ≡ GM_BH/c²), and the eccentricity is large ate₀ ≳ 0.8. Systems of this sort may be generated through the dynamical evolution of a triple system, as well as by other means.