Speaker
Description
Theoretical models and observations suggest that large fractions of Pop III stars end as black holes (BHs) in High-Mass-X-ray Binaries (BH-HMXBs), which are sources of hard X-rays and synchrotron relativistic jets called Microquasars (MQs ref.1). The hard X-rays from these accreting BHs of Pop III have long free paths, pre-heat the Intergalactic Medium (IGM), and lead to a smooth end of the re-ionization epoch (ref. 2).
We will show that the relativistic jets from the remnants of Pop III stars, namely, the BH-HMXB-MQs of Pop III, produce a Synchrotron Cosmic Radio Background (CRB) that can account for the excess amplitude and bottom-flat absorption of atomic hydrogen at z~17 (78 MHz), tentatively reported by EDGES (ref. 3). In fact, the existence of a Synchrotron CRB had been inferred from the NASA ARCADE 2 Experiment (ref. 4). Recently, it was proposed that --along with the hard X-ray cosmic background-- that CRB is the smoking gun of Pop III stars (ref. 5).
References:
1) Mirabel, I.F. & Rodríguez, L.F. 1998, Nature, 392, 673-677
2) Mirabel I. F., Dijkstra M., Laurent Ph., Loeb A., Pritchard J. R., 2011, A&A, 528, A149
3) Bowman J. D., Rogers A. E. E., Monsalve R. A., Mozdzen T. J., Mahesh N., 2018, Nature, 555, 67 EP
4) Fixsen D.J., Kogut A., Levin, S. et. al. 2011, ApJ, 734, 5
5) Mirabel (2019): Review at IAU Symp. 346 (arXiv#1902.00511)
