العطاس المجرّي: الفقاعات الناتجة عن الثقب الأسود سريع

الملخص الأصلي

كما كتبه المؤلفون، بالإنجليزية arXiv:2603.20740

Unlike the complicated X-ray and radio structure observed in the North Polar Spur area, the South-Eastern part of the eROSITA bubbles can be reasonably well described as a propagating forward shock, plausibly created by the transient energy release at the Galactic Center. In this model, the physical radius of the bubble is $$R_{\rm b}\sim 7-8\,{\rm kpc}$$ and the age of the outburst is $$t_{\rm age}\sim 5-8\,{\rm Myr}$$. The visible segment of the shock front (located at a distance of $$\sim 10-12\,{\rm kpc}$$ above the Galactic Disk and at a similar distance from the Sun) is currently expanding with the velocity $$\sim 700\,{\rm km\,s^{-1}}$$ through the gas with density $$n_e\sim 3\times 10^{-4}\,{\rm cm^{-3}}$$, and the abundance of heavy elements in this gas is $$Z\lesssim 0.1 \times Z_\odot$$. Unlike constraints derived from the line-of-sight-integrated quantities, these are effectively in situ measurements of the circumgalactic medium (CGM) properties. Given the simplifying assumptions used in deriving the density, we assign a factor of 2 systematic uncertainty to the final estimate. An eventual decisive test for the shock properties can be provided by the velocity measurements of the X-ray-emitting gas with soft X-ray bolometers. The extended forward shock propagating through low-metallicity gas is a favorable site to accelerate very high-energy cosmic rays, which might contribute to the observed proton-rich galactic cosmic ray component at PeV energies.