A Forty Year Journey. (arXiv:2102.13000v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Genzel_R/0/1/0/all/0/1">Reinhard Genzel</a>
I try to describe the stepwise progress in proving that massive black holes
do exist in the Universe. As compared to forty years ago, measurements have
pushed the ‘size’ of the 4 million solar mass concentration in the Galactic
Center downward by almost 10^6, and its density up by 10^18. Looking ahead
toward the future, the question is probably no longer whether SgrA* must be a
MBH, but rather whether GR is correct on the scales of the event horizon,
whether space-time is described by the Kerr metric and whether the ‘no hair
theorem’ holds. Further improvements of the VLT interferometer GRAVITY (to
GRAVITY+) and the next generation 25-40m telescopes (the ESO-ELT, the TMT and
the GMT) promise further progress. A test of the no hair theorem in the
Galactic Center might come from combining the stellar dynamics with EHT
measurements of the photon ring of SgrA*.
I try to describe the stepwise progress in proving that massive black holes
do exist in the Universe. As compared to forty years ago, measurements have
pushed the ‘size’ of the 4 million solar mass concentration in the Galactic
Center downward by almost 10^6, and its density up by 10^18. Looking ahead
toward the future, the question is probably no longer whether SgrA* must be a
MBH, but rather whether GR is correct on the scales of the event horizon,
whether space-time is described by the Kerr metric and whether the ‘no hair
theorem’ holds. Further improvements of the VLT interferometer GRAVITY (to
GRAVITY+) and the next generation 25-40m telescopes (the ESO-ELT, the TMT and
the GMT) promise further progress. A test of the no hair theorem in the
Galactic Center might come from combining the stellar dynamics with EHT
measurements of the photon ring of SgrA*.
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