Implications of axionic hair on shadow of M87*

Understand

Detection of axion field can unfold intriguing facets of our universe in several astrophysical and cosmological scenarios.

• In four dimensions, such a field owes its origin to the completely anti-symmetric Kalb-Ramond field strength tensor.
• Its invisibility in the solar system based tests compels one to look for its signatures in the strong field regime.
• The recent observation of the shadow of the supermassive black hole in the galaxy M87 ushers in a new opportunity to test for the footprints of axion in the near horizon region of black holes, where the gravity is expected to be strong.