2024/03/05 by Li, Guang-Xing
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2403.02612
The Jeans criterion sets the foundation of our understanding of gravitational collapse. Jog studied the fragmentation of gas under external tides and derived a dispersion relation l' = l\rm Jeans \frac1 (1 + λ0' / 4 πG ρ0)1/2 . She further concludes that the Jeans mass is m\rm incorrect'=m\rm Jeans ( 1/(1 + λ0' / 4 πG ρ0)3/2). We clarify that due to the inhomogeneous nature of tides, this characteristic mass is incorrect. Under weak tides, the mass is m ≈ ρ l1 l2 l3, where the modifications to Jeans lengths along all three dimensions need to be considered; when the tide is strong enough, collapse can only occur once 1 or 2 dimensions. In the latter case, tides can stretch the gas, leading to the formation of filaments.