Investigating the existence of gravitomagnetic monopole in M87* M. Ghasemi-Nodehi, Chandrachur Chakraborty, Qingjuan Yu and Youjun Lu Eur. Phys. J. C, 81 10 (2021) 939 Published online: 23 October 2021 DOI: 10.1140/epjc/s10052-021-09696-3