Abstract
While I have been telling the tale of the VLT, and since we have witnessed earlier in this story the arrival on the scene of active galactic nuclei (AGN), accompanied discreetly by speculations about black holes, I hope the reader has been awaiting this chapter with bated breath. During the ensuing 20 years, attention has become more and more focused on the likely presence of a massive black hole at the center of the Galaxy. With the efforts of Reinhard Genzel, Frank Eisenhauer, Guy Perrin, and many others, this still mysterious object gradually assumed an important place in the preparation of the interferometer, its construction, and its final implementation. Here then is the grand finale which I was hinting at when we met at the top of Paranal in the first pages of this book. But in order to fully appreciate the achievement and before going into the details, I must begin by describing the historical context of black holes.
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Notes
- 1.
“Due to its attraction, a light-emitting body of the same density as the Earth and with a diameter 250 times greater than that of the Sun would not allow any of its light rays to reach us. It is thus possible that the largest light-emitting bodies in the Universe may, for this reason, actually be invisible.” Pierre Simon de Laplace in Exposition du Système du Monde, 1796.
- 2.
See the books by P. Binetruy, G. Chardin, and J.-P. Luminet cited in the bibliography.
- 3.
The constant G determines the acceleration due to gravity g at the surface of the Earth in terms of the mass of the Earth. The value is g = 9.81 m/s2. This acceleration is in turn what determines the weight W of a body of mass m through the relation W = mg.
- 4.
Quoted by Thibaut Damour. In Les trous noirs: leur nature, et leur rôle en physique et astrophysique, Académie des sciences, February 2018. See http://www.academie-sciences.fr/fr/Colloquesconferences-et-debats/trous-noirs-nature-et-role.html.
- 5.
“I am a bird: see my wings …What makes a bird? The plumage, of course. I am a mouse.” J. de La Fontaine, The Bat and the Weasels.
- 6.
It was the theoretical physicist Eugene Wigner (1902–1995) who spoke of the “unreasonable effectiveness of mathematics”. He was of Hungarian origin but naturalised American, winning the Nobel Prize for Physics in 1963.
- 7.
See in the bibliography R. Omnès, La révélation des lois de la physique, O. Jacob, 2008.
- 8.
The event was celebrated on 5 April 2016 at the Académie des sciences in Paris by a series of talks. These can be accessed on http://www.academie-sciences.fr/fr/Colloques-conferences-et-debats/ondesgravitationnelles-et-coalescence-de-trous-noirs.html/.
- 9.
This mode of operation of radiofrequency interferometry is known as very long baseline interferometry (VLBI).
- 10.
The name is perhaps rather surprising. This infrared camera worked in a slightly different way to the CCD cameras already mentioned. Indeed, it was a charge injection device or CID. But from there to imagining its desire for Chimène’s eyes, like Rodrigue, the famous hero of Pierre Corneille’s play Le Cid …!
- 11.
- 12.
Note that the engineers, such as Pascal Puget and others in this case, never appear among the authors for these papers, and yet without them, NAOS would never have existed. This may seem surprising, but there is a kind of silent agreement in research centers that papers of an astrophysical nature will be signed by astronomers, while those of a technological nature, equally innovative and just as essential, are signed by the engineers. However, their role is crucial at every stage and I am not sure that this rather traditional way of sharing the ‘glory’ can really be justified.
- 13.
Comment in the same issue of Nature, p. 614.
- 14.
Simons and Maillard (1996). Thibaut used a rather special kind of device called a Fourier transform spectrometer, named after the same Joseph Fourier already mentioned. This particular instrument, called BEAR, was designed by the French astronomer Jean-Pierre Maillard, who spent his whole professional life perfecting this kind of system, ideal now for observing the galactic center and a good many other objects.
- 15.
Eisenhauer (2006). The perfectly suited name GRAVITY was suggested by Andreas Glindemann, who ran the VLTI programme at the ESO.
- 16.
There is actually a second bright star, called IRSNW, which is close enough to be used, and is in fact used. For clarity in our description, we shall only refer to the star IRS16C.
- 17.
These were two students from the École polytechnique. The first was Denis Mourard, who subsequently worked with Antoine Labeyrie on the GI2T on the Calern Plateau, then made a major contribution to equipping the Californian interferometer CHARA with a spectrograph in the visible. The second student was Nicolas Mercouroff, who chose another direction after his Master’s degree.
- 18.
T. Paumard, Scientific prospects for the VLTI in the Galactic Center: getting to the Schwarzschild radius. In The power of optical/IR interferometry, Springer, 2006. More detail can be found in M. Grould, F. Vincent, T. Paumard, G. Perrin, General relativistic effects on the orbit of the S2 star with GRAVITY, Astr. Ap. 608, A60 (2017).
- 19.
- 20.
GRAVITY: le chasseur de trou noir, Le Monde, 10 May 2016.
- 21.
Seen from the Earth, the velocity of S2 can be decomposed into two components: one in the plane of the sky, which is what is determined by measuring its positions on a nightly basis, and the component perpendicular to that, along the line of sight, derived from the velocity, itself measured by using the Doppler effect.
- 22.
References
L. Blanchet, Les ondes gravitationnelles. Reflets de la Physique, vol. 52 (2017)
A. Broderick, A. Loeb, Portrait of a black hole, Scientific American, Special issue 22 (2013)
A. Eckart, R. Genzel, Observations of stellar proper motions near the Galactic center. Nature 383, 415–417 (1996)
EHT Collaboration, First M87 Event Horizon Telescope Results. I. The shadow of the supermassive black hole in the center of the M87 galaxy. Astrophys. J. 875, L1–17 (2019)
A. Einstein, Annalen der Physik 35, 898–908 (1911)
F. Eisenhauer, GRAVITY. The AO-assisted, two-object beam-combiner, in The Power of Optical/IR Interferometry (Springer, Berlin, 2006)
F. Eisenhauer et al., GRAVITY: observing the universe in motion, ESO Messenger 143, 16–24 (2011)
R. Genzel, R. Schödel, T. Ott, A. Eckart, T. Alexander, F. Lacombe, D. Rouan, B. Aschenbach, Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre. Nature 425, 934 (2003)
A. Ghez et al., High proper-motion stars in the vicinity of Sagittarius A*: evidence for a supermassive black hole at the center of our galaxy. Ap. J. 309, 678 (1998)
Gravity Collaboration, First light for GRAVITY: phase referencing optical interferometry for the Very Large Telescope Interferometer. Astron. Astrophys. 602, A94 (2017)
Gravity Collaboration, Detection of the gravitational redshift in the orbit of the star S2 near the Galactic center massive black hole, Astron. Asrophys. 615, L15 (2018)
Gravity Collaboration, Detection of orbital motions near the last stable circular orbit of the massive black hole SgrA*. Astron. Astrophys. 618, L10 (2018)
S. Issaoun et al., The size, shape, and scattering of SgrA* at 86 GHz: First VLBI with ALMA. Astrophys. J. 871, 30 (2019)
K.Y. Lo et al., On the size of the galactic center compact radio source: diameter < 20 AU. Nature 315, 124 (1985)
A. Mérand et al., GRAVITY science verification. ESO Messenger 170, 16–19 (2017)
R. Narayan, Sparks of interest. Nature 425, 908 (2003)
A.E. Rogers et al., Small-scale structure and position of Sagittarius A* from VLBI at 3 millimeter wavelength. Astrophys. J. 434, L59 (1994)
D. Rouan et al., Near-IR images of the torus and micro-spiral structure in NGC 1068 using adaptive optics. Astron. Astrophys. 339, 687 (1998)
R. Schödel et al., A star in a 15.2-year orbit around the supermassive black hole at the center of the Milky Way. Nature 419, 694–696 (2002)
R. Schödel et al., Stellar dynamics in the central arcsec of our Galaxy. Astrophys. J. 596, 1015 (2003)
K. Schwarzschild, Über das Gravitationelfeld eines Massenpunktes nach der Einsteinchen Theorie, Sitzungsberichte der Königlich Preußischen Akademie der Wissenschaften (Berlin) (1916), pp. 189–196
D. Simons, J.-P. Maillard, Fourier imaging spectroscopy of the Galactic Center. Publ. Astr. Soc. Pac. 102, 232 (1996)
F.H. Vincent, T. Paumard, G. Perrin, L. Mugnier, F. Eisenhauer, S. Gillessen, Performance of astrometric detection of a hotspot orbiting on the innermost stable circular orbit of the galactic center black hole. Mon. Not. Roy. Soc. 412, 2653 (2011)
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Léna, P. (2020). Our Neighbour, the Black Hole. In: Astronomy’s Quest for Sharp Images. Astronomers' Universe. Springer, Cham. https://doi.org/10.1007/978-3-030-55811-6_7
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