ASTROPHYSICAL CONDITION ON THE ATTOLENSING AS A POSSIBLE PROBE FOR A MODIFIED GRAVITY THEORY

We investigate the wave effect in the gravitational lensing by a black hole with very tiny mass less than 10-19 M sun (solar mass), which is called attolensing, motivated by a recent report that the lensing signature might be a possible probe of a modified gravity theory in the braneworld scenario. We focus on the finite source size effect and the effect of the relative motion of the source to the lens, which are influential to the wave effect in the attolensing. Astrophysical condition that the lensed interference signature can be a probe of the modified gravity theory is demonstrated. The interference signature in the microlensing system is also discussed.

Positronium in Astrophysical Condition

From a physical point of view we analyzed the possibility of observation of the Lα-line of the positronium (Ps). In a broad range of temperatures the processes of recombination to states of Ps with different nl, collisions of Ps with electrons and protons of medium are examined.