Testing the No-Hair Theorem with Sgr A*
The no-hair theorem characterizes the fundamental nature of black holes in general relativity. This theorem can be tested observationally by measuring the mass and spin of a black hole as well as its quadrupole moment, which may deviate from the expected Kerr value. Sgr A*, the supermassive black ho...
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Wiley
2012-01-01
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| Series: | Advances in Astronomy |
| Online Access: | http://dx.doi.org/10.1155/2012/486750 |
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| author | Tim Johannsen |
| author_facet | Tim Johannsen |
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| description | The no-hair theorem characterizes the fundamental nature of black holes in general relativity. This theorem can be tested observationally by measuring the mass and spin of a black hole as well as its quadrupole moment, which may deviate from the expected Kerr value. Sgr A*, the supermassive black hole at the center of the Milky Way, is a prime candidate for such tests thanks to its large angular size, high brightness, and rich population of nearby stars. In this paper, I discuss a new theoretical framework for a test of the no-hair theorem that is ideal for imaging observations of Sgr A* with very long baseline interferometry (VLBI). The approach is formulated in terms of a Kerr-like spacetime that depends on a free parameter and is regular everywhere outside of the event horizon. Together with the results from astrometric and timing observations, VLBI imaging of Sgr A* may lead to a secure test of the no-hair theorem. |
| format | Article |
| id | doaj-art-2edae06bcce244ca90f0308e3bfec3fd |
| institution | OA Journals |
| issn | 1687-7969 1687-7977 |
| language | English |
| publishDate | 2012-01-01 |
| publisher | Wiley |
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| series | Advances in Astronomy |
| spelling | doaj-art-2edae06bcce244ca90f0308e3bfec3fd2025-08-20T02:07:52ZengWileyAdvances in Astronomy1687-79691687-79772012-01-01201210.1155/2012/486750486750Testing the No-Hair Theorem with Sgr A*Tim Johannsen0Physics Department, University of Arizona, 1118 E. 4th Street, Tucson, AZ 85721, USAThe no-hair theorem characterizes the fundamental nature of black holes in general relativity. This theorem can be tested observationally by measuring the mass and spin of a black hole as well as its quadrupole moment, which may deviate from the expected Kerr value. Sgr A*, the supermassive black hole at the center of the Milky Way, is a prime candidate for such tests thanks to its large angular size, high brightness, and rich population of nearby stars. In this paper, I discuss a new theoretical framework for a test of the no-hair theorem that is ideal for imaging observations of Sgr A* with very long baseline interferometry (VLBI). The approach is formulated in terms of a Kerr-like spacetime that depends on a free parameter and is regular everywhere outside of the event horizon. Together with the results from astrometric and timing observations, VLBI imaging of Sgr A* may lead to a secure test of the no-hair theorem.http://dx.doi.org/10.1155/2012/486750 |
| spellingShingle | Tim Johannsen Testing the No-Hair Theorem with Sgr A* Advances in Astronomy |
| title | Testing the No-Hair Theorem with Sgr A* |
| title_full | Testing the No-Hair Theorem with Sgr A* |
| title_fullStr | Testing the No-Hair Theorem with Sgr A* |
| title_full_unstemmed | Testing the No-Hair Theorem with Sgr A* |
| title_short | Testing the No-Hair Theorem with Sgr A* |
| title_sort | testing the no hair theorem with sgr a |
| url | http://dx.doi.org/10.1155/2012/486750 |
| work_keys_str_mv | AT timjohannsen testingthenohairtheoremwithsgra |