Testing General Relativity with Stellar Orbits around the Supermassive Black Hole in Our Galactic Center

The general theory of relativity predicts that a star passing close to a supermassive black hole should exhibit a relativistic redshift. In this study, we used observations of the Galactic Center star S0-2 to test this prediction. We combined existing spectroscopic and astrometric measurements from 1995–2017, which cover S0-2’s 16-year orbit, with measurements from March to September 2018, which cover three events during S0-2’s closest approach to the black hole. We detected a combination of special relativistic and gravitational redshift, quantified using the redshift parameter ϒ. Our result, ϒ = 0.88 ± 0.17, is consistent with general relativity (ϒ = 1) and excludes a Newtonian model (ϒ = 0) with a statistical significance of 5σ.

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The Shortest-Known–Period Star Orbiting Our Galaxy’s Supermassive Black Hole

Science ◽

10.1126/science.1225506 ◽

2012 ◽

Vol 338 (6103) ◽

pp. 84-87 ◽

Cited By ~ 131

Author(s):

L. Meyer ◽

A. M. Ghez ◽

R. Schödel ◽

S. Yelda ◽

A. Boehle ◽

...

Keyword(s):

General Relativity ◽

Black Hole ◽

Gravitational Potential ◽

Angular Resolution ◽

Galactic Center ◽

Data Set ◽

Supermassive Black Hole ◽

The Past ◽

Orbital Periods

Stars with short orbital periods at the center of our Galaxy offer a powerful probe of a supermassive black hole. Over the past 17 years, the W. M. Keck Observatory has been used to image the galactic center at the highest angular resolution possible today. By adding to this data set and advancing methodologies, we have detected S0-102, a star orbiting our Galaxy’s supermassive black hole with a period of just 11.5 years. S0-102 doubles the number of known stars with full phase coverage and periods of less than 20 years. It thereby provides the opportunity, with future measurements, to resolve degeneracies in the parameters describing the central gravitational potential and to test Einstein’s theory of general relativity in an unexplored regime.

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Constraining scalar-tensor gravity models by S2 star orbits around the galactic center

Facta universitatis - series Physics Chemistry and Technology ◽

10.2298/fupct1901011b ◽

2019 ◽

Vol 17 (1, spec.issue) ◽

pp. 11-20

Author(s):

Vesna Borka-Jovanovic ◽

Predrag Jovanovic ◽

Dusko Borka ◽

Salvatore Capozziello ◽

Stefania Gravina ◽

...

Keyword(s):

General Relativity ◽

Black Hole ◽

Galactic Center ◽

Newtonian Limit ◽

Gravity Models ◽

Kinematics And Dynamics ◽

Supermassive Black Hole ◽

Theories Of Gravity ◽

Orbital Precession ◽

Best Fit

The aim of our investigation is to derive a particular theory among the class of scalar-tensor(ST) theories of gravity, and then to test it by studying kinematics and dynamics of S-stars around a supermassive black hole (BH) at Galactic Center (GC). We also discuss the Newtonian limit of this class of ST theories of gravity, as well as its parameters. We compare the observed orbit of S2 star with our simulated orbit which we obtained theoretically with the derived ST potential and constrained parameters. Using the obtained best-fit parameters we calculated orbital precession of S2 star in ST gravity and found that it has the same direction as in General Relativity (GR) but causes much larger pericenter shift.

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15 years of high precision astrometry in the Galactic Center

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308019820 ◽

2007 ◽

Vol 3 (S248) ◽

pp. 466-469

Author(s):

S. Gillessen ◽

R. Genzel ◽

F. Eisenhauer ◽

T. Ott ◽

S. Trippe ◽

...

Keyword(s):

Black Hole ◽

Mass Distribution ◽

Near Infrared ◽

Galactic Center ◽

Massive Black Hole ◽

Data Set ◽

Stellar Orbits ◽

Supermassive Black Hole ◽

Near Future ◽

Precision Astrometry

AbstractIn 1992, we obtained the first observations of S2 a star close to the supermassive black hole at the Galactic Center. In 2002, S2 passed its periastron and in 2007, it completed a first fully observed revolution. This orbit allowed us to determine the mass of and the distance to the supermassive black hole with unprecedented accuracy. Here we present a re-analysis of the data set, enhancing the astrometric accuracy to 0.5 mas and increasing the number of well-determined stellar orbits to roughly 15. This allows to constrain the extended mass distribution around the massive black hole and will lead in the near future to the detection of post-Newtonian effects. We will also give an outlook on the potential of interferometric near-infrared astrometry with 10 microarcsecond accuracy from the VLTI.

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Statistical Challenges in fitting stellar orbits around the super-massive black hole at the Galactic center

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316012175 ◽

2016 ◽

Vol 11 (S322) ◽

pp. 239-240

Author(s):

Gregory D. Martinez ◽

Kelly Kosmo ◽

Aurelien Hees ◽

Joseph Ahn ◽

Andrea Ghez

Keyword(s):

General Relativity ◽

Black Hole ◽

Galactic Center ◽

Massive Black Hole ◽

Parameter Spaces ◽

Stellar Orbits ◽

Tests Of General Relativity ◽

Short Period ◽

Statistical Issues ◽

Radial Velocity Data

AbstractOver two decades of astrometric and radial velocity data of short period stars at the Galactic center has the potential to provide unprecedented tests of General Relativity and insight into the astrophysics of the super-massive black hole. Fundamental to this is understanding the underlying statistical issues of fitting stellar orbits. Unintended prior effects can obscure actual physical effects from General Relativity and underlying extended mass distribution. At the heart of this is dealing with large parameter spaces inherent to multi-star fitting and ensuring acceptable coverage properties of the resulting confidence intervals in the Bayesian framework. This proceeding will detail some of the UCLA group's analysis and work in addressing these statistical issues.

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The Galactic Center: An Improved Astrometric Reference Frame for Stellar Orbits around the Supermassive Black Hole

The Astrophysical Journal ◽

10.3847/1538-4357/ab0361 ◽

2019 ◽

Vol 873 (1) ◽

pp. 65 ◽

Cited By ~ 7

Author(s):

Shoko Sakai ◽

Jessica R. Lu ◽

Andrea Ghez ◽

Siyao Jia ◽

Tuan Do ◽

...

Keyword(s):

Black Hole ◽

Reference Frame ◽

Galactic Center ◽

Stellar Orbits ◽

Supermassive Black Hole

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On the Origin of the Galactic Center S Stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310006605 ◽

2009 ◽

Vol 5 (S267) ◽

pp. 330-330

Author(s):

Evgeny Griv

Keyword(s):

Black Hole ◽

Galactic Center ◽

Galactic Rotation ◽

Concentrated Mass ◽

Stellar Orbits ◽

Supermassive Black Hole ◽

Disk Rotation ◽

Single Disk ◽

Sgr A ◽

Central Parsec

Most, if not all, galaxies with a significant bulge component harbor a central supermassive black hole. In our own Milky Way Galaxy, a disk of stars at a distance r ~ 0.05–1 pc orbits the radio source Sgr A* at the center. Stellar orbits show that the gravitational potential on a scale of ~ 0.5 pc is dominated by a concentrated mass of MBH ≈ 3.6 × 106M⊙, which is associated with a supermassive black hole. In addition to the black hole, the models require the presence of an extended mass of (0.5–1.5) × 106M⊙ in the central parsec, which can be explained well by the mass of the stars that make up the cluster. Thus, the Galactic center star cluster is composed of a central supermassive black hole and a self-gravitating disk that is several Gyrs old and comprised of late-type CO absorption stars. Significant disk rotation in the sense of the general Galactic rotation has been detected. This system is probably a strongly warped, thin single disk; the mean eccentricity of the observed stellar orbits in the disk is e ≈ 0.36 ± 0.06.

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Star's rosette-shaped orbit around a supermassive black hole supports general relativity

AccessScience ◽

10.1036/1097-8542.br0429201 ◽

2020 ◽

Keyword(s):

General Relativity ◽

Black Hole ◽

Supermassive Black Hole

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MONITORING STELLAR ORBITS AROUND THE MASSIVE BLACK HOLE IN THE GALACTIC CENTER

The Astrophysical Journal ◽

10.1088/0004-637x/692/2/1075 ◽

2009 ◽

Vol 692 (2) ◽

pp. 1075-1109 ◽

Cited By ~ 1006

Author(s):

S. Gillessen ◽

F. Eisenhauer ◽

S. Trippe ◽

T. Alexander ◽

R. Genzel ◽

...

Keyword(s):

Black Hole ◽

Galactic Center ◽

Massive Black Hole ◽

Stellar Orbits

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Null Geodesics and Strong Field Gravitational Lensing in a String Cloud Background

Advances in High Energy Physics ◽

10.1155/2015/635625 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

M. Sharif ◽

Sehrish Iftikhar

Keyword(s):

Black Hole ◽

Gravitational Lensing ◽

Galactic Center ◽

Deflection Angle ◽

Orbital Motion ◽

Strong Field ◽

Schwarzschild Black Hole ◽

Field Limit ◽

Null Geodesics ◽

Supermassive Black Hole

This paper is devoted to studying two interesting issues of a black hole with string cloud background. Firstly, we investigate null geodesics and find unstable orbital motion of particles. Secondly, we calculate deflection angle in strong field limit. We then find positions, magnifications, and observables of relativistic images for supermassive black hole at the galactic center. We conclude that string parameter highly affects the lensing process and results turn out to be quite different from the Schwarzschild black hole.

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