The central parsec of the Galaxy contains dozens of massive stars with a cumulative mass-loss rate of ∼10-3 M⊙ yr -1. Shocks among these stellar winds produce the hot plasma that pervades the central part of the Galaxy. We argue that these stellar wind shocks also efficiently accelerate electrons and protons to relativistic energies. The relativistic electrons inverse Compton scatter the ambient ultraviolet and far-infrared radiation field, producing high-energy γ-rays with a roughly constant luminosity from ∼GeV to ∼10 TeV. This can account for the TeV source seen by HESS in the Galactic center. Our model predicts a GLAST counterpart to the HESS source with a luminosity of ≈1035 ergs s-1 and cooling break at ≈4 GeV. Synchrotron radiation from the same relativistic electrons should produce detectable emission at lower energies, with a surface brightness of ≈10-14B-3 2, ergs s1 cm-2 arcsec-2 from ∼THz to ∼keV, where B3 is the magnetic field strength in units of mG. The observed level of diffuse thermal X-ray emission in the central parsec requires B ≲ 300 μG in our models. Future detection of the diffuse synchrotron background in the central parsec can directly constrain the magnetic field strength, providing an important boundary condition for models of accretion onto Sgr A*.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
- Galaxy: center
- Radiation mechanisms: nonthermal
- Radiation mechanisms: thermal