An international team of astrophysicists has found distinctive signatures of black hole event horizons, unmistakably separating them from neutron stars, which are objects comparable to black holes in mass and size but confined within a hard surface. This is by far the strongest steady signature of stellar-mass black holes to date. The team consisting of Mr. Srimanta Banerjee and Professor Sudip Bhattacharyya from the Tata Institute of Fundamental Research, India, and Professor Marat Gilfanov and Professor Rashid Sunyaev from Max Planck Institute for Astrophysics, Germany and Space Research Institute of Russian Academy of Sciences, Russia is publishing this research in a paper that has been accepted for publication in Monthly Notices of the Royal Astronomical Society.