2020ApJ...904L..14G

We propose a novel method to constrain the Milky Way (MW) mass M_vir with its corona temperature observations. For a given corona density profile, one can derive its temperature distribution assuming a generalized equilibrium model with nonthermal pressure support. While the derived temperature profile decreases substantially with radius, the X-ray-emission-weighted average temperature, which depends most sensitively on M_vir, is quite uniform toward different sight lines, consistent with X-ray observations. For a Navarro-Frenk-White (NFW) total matter distribution, the corona density profile should be cored, and we constrain M_vir=(1.19–2.95)×10¹²M_☉. For a total matter distribution contributed by an NFW dark matter profile and central baryons, the corona density profile should be cuspy and M_vir,dm=(1.34–5.44)×10¹²M_☉. Nonthermal pressure support leads to even higher values of M_vir, while a lower MW mass may be possible if the corona is accelerating outward. This method is independent of the total corona mass, its metallicity, and temperature at very large radii.