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Is Something Else Hidden at the Center of the Milky Way?

Is Something Else Hidden at the Center of the Milky Way?
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Center of the Milky Way

In this drawing, the stars are seen in close orbit around the supermassive black hole known as Sagittarius A* (Sgr A*) lurking at the center of the Milky Way. Credit: International Gemini Observatory / NOIRLab / NSF / AURA / J. da Silva / (Spaceengine), Acknowledgments: M. Zamani (NSF’s NOIRLab)[2]Definitive Insights on the Supermassive Black Hole at the Heart of the Milky Way

Astronomers use Gemini Observatory and an international telescope collaboration to shine a light on Sagittarius A*

Obtained with the help of the Gemini North telescope, astronomers have made the most precise measurements ever of the movements of stars around supermassive stars.[{” attribute=””>black hole at the center of the Milky Way. These results show that 99.9% of the mass contained at the very center of the galaxy is due to the black hole, and only 0.1% could include stars, smaller black holes, interstellar dust, and gas, or dark matter.

Astronomers have measured the position and velocity of four stars in the vicinity of Sagittarius A* (Sgr A*) more precisely than ever before.[1] Supermassive black hole lurking in the center of the Milky Way. The motions of these stars, designated S2, S29, S38, and S55, are almost entirely due to the mass at the center of the Milky Way. Commander A* The black hole leaves little room for anything else.

The research team used a variety of cutting-edge astronomical facilities in this research. To measure the speeds of the stars, they used spectroscopy from the Gemini Near Infrared Spectrograph (GNIRS) and SINFONI instrument at Gemini North near Maunakea peak in Hawaii, part of the international Gemini Observatory, a program of NSF’s NOIRLab. at the European Southern Observatory[{” attribute=””>Çok Büyük Teleskop. VLTI’deki GRAVITY aleti, yıldızların konumlarını ölçmek için kullanıldı.

Kara Delik Yay A

Samanyolu’nun merkezindeki Yay A * kara deliğinin çizimi. Kredi: Uluslararası İkizler Gözlemevi / NOIRLab / NSF / AURA / J. da Silva / (Spaceengine), Teşekkür: M. Zamani (NSF’s NOIRLab)

Max Planck Dünya Dışı Fizik Enstitüsü müdürü ve 2020 Nobel Fizik Ödülü’nün eş sahibi Reinhard Genzel, “GNIRS cihazı bize ihtiyacımız olan kritik bilgileri veren Gemini Gözlemevi’ne çok minnettarız” dedi. “Bu araştırma, dünya çapındaki işbirliğini en iyi şekilde gösteriyor.”

Güneş’ten kabaca 27.000 ışıkyılı uzaklıkta bulunan Samanyolu’nun Galaktik Merkezi, gökbilimcilerin Güneş’ten 4,3 milyon kat daha büyük kütleli süper kütleli bir kara delik olarak tanımladıkları kompakt radyo kaynağı Sgr A*’yı içerir. Onlarca yıl süren özenli gözlemlere ve Sgr A’nın kimliğini keşfettiği için verilen Nobel Ödülü’ne rağmen *[3] – it has been difficult to conclusively prove that most of this mass belongs only to the supermassive black hole, and that it also does not contain huge amounts of matter such as stars and smaller ones. black holesinterstellar dust and gas or dark matter.

ESO's VLTI Images of stars in the Center of the Milky Way

Taken between March and July 2021 by the GRAVITY instrument on ESO’s Very Large Telescope Interferometer (VLTI), these annotated images show stars orbiting very close to Sagittarius A*, the supermassive black hole at the heart of the Milky Way. One of these stars, S29, was observed making its closest approach to the black hole at 13 billion kilometers, just 90 times the distance between the Sun and Earth. Another star, named S300, has been detected for the first time in new VLTI observations reported by ESO.
Using the international Gemini Observatory’s Gemini North, a program of NSF’s NOIRLab and ESO’s VLT, astronomers can measure the positions and velocities of these S29 and S55 stars (as well as S2 and S38) more precisely than ever before. they measured. It moves to indicate that the mass at the center of the Milky Way originates almost entirely from the Sagittarius A* black hole, leaving little room for anything else. Credits: ESO/GRAVITY collaboration

“With the 2020 Nobel Prize in physics for confirmation that Sgr A* is indeed a black hole, we now want to go further. One of the astronomers involved in this study, Stefan Gillessen, asked if there is anything else hidden at the center of the Milky Way and how general relativity is this extreme. “We want to find out if there really is a correct theory of gravity in the lab,” he explained. “The simplest way to answer this question is to closely follow the orbits of stars passing near Sgr A*.”

Einstein’s general theory of relativity predicts that the orbits of stars around a supermassive compact object are very different from those predicted by classical Newtonian physics. In particular, general relativity predicts that the orbits of stars will follow a graceful rosette shape – an effect known as the effect. black shield precession. To really see the stars that trace this badge, the team tracked the position and velocity of four stars in the immediate vicinity of Sgr A*, designated S2, S29, S38, and S55. The team’s observations of how far these stars were advancing allowed them to infer the mass distribution within Sgr A*. They discovered that any extended mass orbiting the S2 star contributes the equivalent of at most 0.1% of the mass of the supermassive black hole.


animated series[{” attribute=””>ESO’s Very Large Telescope Interferometer (VLTI) images of stars around the Milky Way’s central black hole. This animation shows the orbits of the stars S29 and S55 as they move close to Sagittarius A* (center), the supermassive black hole at the heart of the Milky Way. As we follow the stars along in their orbits, we see real images of the region obtained with the GRAVITY instrument on the VLTI in March, May, June and July 2021. In addition to S29 and S55, the images also show two fainter stars, S62 and S300. S300 was detected for the first time in new VLTI observations reported by ESO.

Measuring the minute variations in the orbits of distant stars around our galaxy’s supermassive black hole is incredibly challenging. To make further discoveries, astronomers will have to push the boundaries not only of science but also of engineering. Upcoming extremely large telescopes (ELTs) such as the Giant Magellan Telescope and the Thirty Meter Telescope (both part of the US-ELT Program) will allow astronomers to measure even fainter stars with even greater precision.

“We will improve our sensitivity even further in future, allowing us to track even fainter objects,” concluded Gillessen. “We hope to detect more than we see now, giving us a unique and unambiguous way to measure the rotation of the black hole.”


Zoom into the heart of the Milky Way to see stars observed by the European Southern Observatory’s Very Large Telescope (last observation from 2019). Further zooming reveals stars even closer to the black hole, observed with the GRAVITY instrument on ESO’s Very Large Telescope Interferometry in mid-2021.

“Gemini observatories continue to provide new insights into the nature of our galaxy and the massive black hole at its centre,” said Martin Still, National Science Foundation Gemini Program Officer. “More device development over the next decade designed for broad use will continue NOIRLab’s leadership in characterizing the Universe around us.”

For more information on this research, see Watch Stars Race Around The Milky Way’s Super Massive Black Hole.

Notebook

  1. Sagittarius A* is spoken as “Sagittarius A star”.
  2. ESO’s VLT consists of four separate 8.2-metre telescopes that can combine light through a network of mirrors and underground tunnels using a technique known as interferometry to create the VLTI. GRAVITY uses this technique to measure the position of objects in the night sky at high density.[{” attribute=””>accuracy — equivalent to picking out a quarter-dollar coin on the surface of the Moon.
  3. The 2020 Nobel Prize in Physics was awarded in part to Reinhard Genzel and Andrea Ghez “for the discovery of a supermassive compact object at the center of our galaxy.”

This research is presented in the paper “The mass distribution in the Galactic Centre from interferometric astrometry of multiple stellar orbits” which is published in Astronomy & Astrophysics. A companion paper “Deep Images of the Galactic Center with GRAVITY” has also been published in Astronomy & Astrophysics.

References:

“Mass distribution in the Galactic Center based on interferometric astrometry of multiple stellar orbits” by GRAVITY Collaboration: R. Abuter, N. Aimar, A. Amorim, J. Ball, M. Bauböck, J. P. Berger, H. Bonnet, G. Bourdarot, W. Brandner, V. Cardoso, Y. Clénet, Y. Dallilar, R. Davies, P. T. de Zeeuw, J. Dexter, A. Drescher, F. Eisenhauer, N. M. Förster Schreiber, A. Foschi, P. Garcia, F. Gao, E. Gendron, R. Genzel, S. Gillessen, M. Habibi, X. Haubois, G. Heißel,??, T. Henning, S. Hippler, M. Horrobin, L. Jochum, L. Jocou, A. Kaufer, P. Kervella, S. Lacour, V. Lapeyrère, J.-B. Le Bouquin, P. Léna, D. Lutz, T. Ott, T. Paumard, K. Perraut, G. Perrin, O. Pfuhl, S. Rabien, J. Shangguan, T. Shimizu, S. Scheithauer, J. Stadler, A.W. Stephens, O. Straub, C. Straubmeier, E. Sturm, L. J. Tacconi, K. R. W. Tristram, F. Vincent, S. von Fellenberg, F. Widmann, E. Wieprecht, E. Wiezorrek, J. Woillez, S. Yazici and A. Young, 19 January 2022, Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202142465

“Deep images of the Galactic center with GRAVITY” by GRAVITY Collaboration: R. Abuter, N. Aimar, A. Amorim, P. Arras, M. Bauböck, J. P. Berger, H. Bonnet, W. Brandner, G. Bourdarot, V. Cardoso, Y. Clénet, R. Davies, P. T. de Zeeuw, J. Dexter, Y. Dallilar, A. Drescher, F. Eisenhauer, T. Enßlin, N. M. Förster Schreiber, P. Garcia, F. Gao, E. Gendron, R. Genzel, S. Gillessen, M. Habibi, X. Haubois, G. Heißel, T. Henning, S. Hippler, M. Horrobin, A. Jiménez-Rosales, L. Jochum, L. Jocou, A. Kaufer, P. Kervella, S. Lacour, V. Lapeyrère, J.-B. Le Bouquin, P. Léna, D. Lutz, F. Mang, M. Nowak, T. Ott, T. Paumard, K. Perraut, G. Perrin, O. Pfuhl, S. Rabien, J. Shangguan, T. Shimizu, S. Scheithauer, J. Stadler, O. Straub, C. Straubmeier, E. Sturm, L. J. Tacconi, K. R. W. Tristram, F. Vincent, S. von Fellenberg, I. Waisberg, F. Widmann, E. Wieprecht, E. Wiezorrek, J. Woillez, S. Yazici, A. Young and G. Zins, 19 January 2022, Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202142459

More information

The team behind this result is composed of The GRAVITY Collaboration, R. Abuter (European Southern Observatory), A. Amorim (Universidade de Lisboa and CENTRA – Centro de Astrofísica e Gravitação), M. Bauböck (Max Planck Institute for Extraterrestrial Physics and University of Illinois), J. P. Berger (University Grenoble Alpes and European Southern Observatory), H. Bonnet (European Southern Observatory), G. Bourdarot (University Grenoble Alpes and Max Planck Institute for Extraterrestrial Physics), V. Cardoso (CENTRA – Centro de Astrofísica e Gravitação and CERN), Y. Clénet (LESIA, Observatoire de Paris), Y. Dallilar (Max Planck Institute for Extraterrestrial Physics), R. Davies (Max Planck Institute for Extraterrestrial Physics), P. T. de Zeeuw (Leiden University and Max Planck Institute for Extraterrestrial Physics), J. Dexter (University of Colorado, Boulder), A. Drescher (Max Planck Institute for Extraterrestrial Physics), A. Eckart (University of Cologne and Max Planck Institute for Radio Astronomy), F. Eisenhauer (Max Planck Institute for Extraterrestrial Physics), N. M. Förster Schreiber (Max Planck Institute for Extraterrestrial Physics), P. Garcia (Universidade do Porto and CENTRA – Centro de Astrofísica e Gravitação), F. Gao (Universität Hamburg and Max Planck Institute for Extraterrestrial Physics), E. Gendron (LESIA, Observatoire de Paris), R. Genzel (Max Planck Institute for Extraterrestrial Physics and University of California, Berkeley), S. Gillessen (Max Planck Institute for Extraterrestrial Physics), M. Habibi (Max Planck Institute for Extraterrestrial Physics), X. Haubois (European Southern Observatory), G. Heißel (LESIA, Observatoire de Paris), T. Henning (Max Planck Institute for Astronomy), S. Hippler (Max Planck Institute for Astronomy), M. Horrobin (University of Cologne), L. Jochum (European Southern Observatory), L. Jocou (University Grenoble Alpes), A. Kaufer (European Southern Observatory), P. Kervella (LESIA, Observatoire de Paris), S. Lacour (LESIA, Observatoire de Paris), V. Lapeyrère (LESIA, Observatoire de Paris), J.-B. Le Bouquin (University Grenoble Alpes), P. Léna (LESIA, Observatoire de Paris), D. Lutz (Max Planck Institute for Extraterrestrial Physics), T. Ott (Max Planck Institute for Extraterrestrial Physics), T. Paumard (LESIA, Observatoire de Paris), K. Perraut (University Grenoble Alpes), G. Perrin (LESIA, Observatoire de Paris), O. Pfuhl (European Southern Observatory and Max Planck Institute for Extraterrestrial Physics), S. Rabien (Max Planck Institute for Extraterrestrial Physics), G. Rodríguez-Coira (LESIA, Observatoire de Paris), J. Shangguan (Max Planck Institute for Extraterrestrial Physics), T. Shimizu (Max Planck Institute for Extraterrestrial Physics), S. Scheithauer (Max Planck Institute for Astronomy), J. Stadler (Max Planck Institute for Extraterrestrial Physics), O. Straub (Max Planck Institute for Extraterrestrial Physics), C. Straubmeier (University of Cologne), E. Sturm (Max Planck Institute for Extraterrestrial Physics), L. J. Tacconi (Max Planck Institute for Extraterrestrial Physics), K. R. W. Tristram (European Southern Observatory), F. Vincent (LESIA, Observatoire de Paris), S. von Fellenberg (Max Planck Institute for Extraterrestrial Physics), F. Widmann (Max Planck Institute for Extraterrestrial Physics), E. Wieprecht (Max Planck Institute for Extraterrestrial Physics), E. Wiezorrek (Max Planck Institute for Extraterrestrial Physics), J. Woillez (European Southern Observatory), S. Yazici (Max Planck Institute for Extraterrestrial Physics and the University of Cologne), and A. Young (Max Planck Institute for Extraterrestrial Physics).

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