Speaker: Anupam Ray, Tata Institute Of Fundamental Research, India
Abstract: Unusual masses of the black holes being discovered by gravitational wave experiments pose fundamental questions about the origin of these black holes. More interestingly, black holes with masses smaller than the Chandrasekhar limit (~1.4 solar mass) are essentially impossible to produce through any standard stellar evolution. Black holes of primordial origin, with fine-tuned parameters and with no well-established formation mechanisms, are the most discussed explanation of these objects. In this talk, I will discuss a simple and elegant production channel of sub-Chandrasekhar mass non-primordial black holes. Particle dark matter with no antiparticle counterpart, owing to their interaction with stellar nuclei, can catastrophically accumulate inside compact stars and eventually transmute them to sub-Chandrasekhar mass black holes. Our recent work points out several avenues to test the transmuted origin of low mass black holes, and demonstrates that binary merger rates at high redshift are distinctively different for primordial and transmuted black holes. Measurement of these binary merger rates by the imminent gravitational wave detectors can conclusively determine the origin of low mass black holes.