This comment is devoted to the recalculation of the Casimir energy of a massless scalar field in the Kerr black hole surrounded by quintessence derived in [B. Toshmatov, Z. Stuchl\'{ i}k and B. Ahmedov, Eur. Phys. J. Plus { \bf 132}, 98 (2017)] and its comparison with the results recently obtained in [V. B. Bezerra, M. S. Cunha, L. F. F. Freitas and C. R. Muniz, Mod. Phys. Lett. A { \bf 32}, 1750005 (2017)] in the spacetime [S. G. Ghosh, Eur. Phys. J. C { \bf 76}, 222 (2016)]. We have shown that in the more realistic spacetime which does not have the failures illustrated here, the Casimir energy is significantly bigger than that derived in [V. B. Bezerra, M. S. Cunha, L. F. F. Freitas and C. R. Muniz, Mod. Phys. Lett. A { \bf 32}, 1750005 (2017)], and the difference becomes crucial especially in the regions of near horizons of the spacetime.
Categories: gr-qc