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Joined 2026-09-21 Message
Incoming links: Reinhard Genzel
Galactic-centre stellar-orbit experiments 2026-10-18
Rainer Schödel, Reinhard Genzel and collaborators combined NTT imaging with VLT adaptive-optics infrared observations. Silicon-monoxide masers registered stellar images to the radio position of Sagittarius A*. Their 2002 observations included S2's closest approach; a fitted Kepler orbit constrained a concentrated central mass. Rejecting a particular extended cluster also required its density and survival assumptions.[ref]
Andrea Ghez and collaborators combined Keck speckle imaging and laser-guide-star adaptive optics with infrared spectra. Image fitting supplied angular positions; spectral lines supplied velocities. The 2008 analysis treated optical distortion, coordinate alignment and blended sources: a shifting photocentre can imitate motion. Joint angular and spectral fitting constrained both distance and mass, with assumptions about central radial motion affecting the result. Apparatus calibration and confusion tests are therefore part of the dynamical inference.[ref]
Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits by Andrea M. Ghez and others. PDF §§2–4 and Appendices A–C: imaging, spectroscopy, source confusion and orbital fit
Nobel Prize in Physics in 2020 2026-10-18
One half went to Roger Penrose for showing that black hole formation is a robust prediction of general relativity. One quarter each went to Reinhard Genzel and Andrea Ghez for discovering a supermassive compact object at the centre of the Milky Way.[ref]
The Nobel Prize in Physics 2020 by Nobel Prize Outreach. Individual official summary: Penrose one half for robust relativistic black-hole formation; Genzel and Ghez one quarter each for the Galactic-centre compact object.