Volume and Thermal Energy of the eROSITA Bubbles from X-Ray Surface Brightness

This paper examines the eROSITA bubble thermal energy for the large bipolar structures above and below the Galactic Centre, using only published input values and transparent formulae. The calculation obtains the following headline results: volume_total_kpc3 = 2111.2; volume_total_cm3 = 6.205e+67; temperature_K = 3482000.0; thermal_energy_erg = 2.058e+56; pressure_dyne_cm2 = 2.212e-12; pressure_over_kB_K_cm3 = 16015.0. Each quantity is derived step by step from the stated inputs, so that any reader can reproduce or rescale every number from the deposited calculation script, a point that bears directly on the eROSITA bubble thermal energy. In the context of the eROSITA bubble thermal energy, the results are compared with independent published estimates where those exist, and disagreements are reported at their actual size rather than absorbed into the assumptions. The conclusions are limited to what the budget arithmetic supports: the eROSITA bubble thermal energy is constrained to the range the current published values permit, and the dominant remaining uncertainty is identified explicitly.