Encounters
Telemetry ○𓆪｜encounter｜ENC｜20260912181021-02-•
Three historic milestones in stellar BH research are separated by roughly one human generation, namely, Einstein’s 1915 paper on GR, Oppenheimer and Snyder’s 1939 paper on gravitational collapse, and the 1972 identification of BH Cyg X–1 (see §1). Now, one more generation later, we have measured or constrained the masses of 20 BHBs and obtained spin estimates for two of them. As described herein, a rich X-ray data archive, as well as ongoing observations, are providing an intimate look at the behavior of transient BHs as they vary in X-ray luminosity by 5–8 orders of magnitude. We have obtained strong circumstantial evidence for the existence of the event horizon, and observed harmonic pairs of HFQPOs and relativistically-broadened Fe lines emanating from near the ISCO. However, the RXTE detectors are unable to resolve the Fe K line, and the HFQPOs are all near the limiting sensitivity of the mission. Further major advances will require a new timing mission with order-of-magnitude increases in detector area, telemetry capability, and spectral resolving power. It is important to press ahead with a new timing mission soon in order to complement effectively the vigorous programs underway in gravitational wave astronomy and in observational studies of supermassive and intermediate-mass BHs.
Source: Remillard & McClintock 2006 ┃ X-Ray Properties… ⚬𓂃
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