Oscillating axion bubbles as an alternative to supermassive black holes at galactic centers Academic Article uri icon

abstract

  • Recent observations of near-infrared and x-ray flares from Sagittarius A *, which is believed to be a supermassive black hole at the galactic center, show that the source exhibits about 20min periodic variability. Here we provide arguments based on a quantitative analysis that supermassive objects at galactic centers may be bubbles of dark matter axions rather than black holes. An oscillating axion bubble can explain the periodic variability of Sagittarius A * and yields the axion mass of about 0.6meV which fits in the open axion mass window. The bubble scenario with no other free parameters explains the lack of supermassive 'black holes' with mass . Low-mass bubbles decay fast and as a result are very rare. We also found that the mass of an axion bubble cannot exceed , in agreement with the upper limit on the supermassive 'black hole' mass obtained from observations. Our finding, if confirmed, suggests that Einstein general relativity is invalid for strong gravity and the gravitational field for the bubble effectively becomes repulsive at large potential. Imaging a shadow of the 'black hole' at the galactic center with the VLBA (very long-baseline array) in the next decade could distinguish between the black hole and the oscillating axion bubble scenarios. In the case of the axion bubble, a steady shadow will not be observed. Instead, the shadow will appear and disappear periodically with a period of about 20min. © IOP Publishing Ltd.

published proceedings

  • JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS

author list (cited authors)

  • Svidzinsky, A. A.

citation count

  • 3

complete list of authors

  • Svidzinsky, Anatoly A

publication date

  • October 2007