scholarly journals 15 years of high precision astrometry in the Galactic Center

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.

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

2009 ◽  
Vol 692 (2) ◽  
pp. 1075-1109 ◽  
Author(s):  
S. Gillessen ◽  
F. Eisenhauer ◽  
S. Trippe ◽  
T. Alexander ◽  
R. Genzel ◽  
...  
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Massive Black Hole ◽  
Stellar Orbits

Clarification of the formation process of the super massive black hole by Infrared astrometric satellite, Small-JASMINE

2017 ◽  
Vol 12 (S330) ◽  
pp. 360-361 ◽  
Author(s):  
Taihei Yano ◽  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Phase Space ◽  
Formation Process ◽  
Near Infrared ◽  
Galactic Center ◽  
Space Distribution ◽  
Massive Black Hole ◽  
Phase Space Distribution ◽  
Merging Process

AbstractSmall-JASMINE (hearafter SJ), infrared astrometric satellite, will measure the positions and the proper motions which are located around the Galactic center, by operating at near infrared wave-lengths. SJ will clarify the formation process of the super massive black hole (hearafter SMBH) at the Galactic center. In particular, SJ will determine whether the SMBH was formed by a sequential merging of multiple black holes. The clarification of this formation process of the SMBH will contribute to a better understanding of merging process of satellite galaxies into the Galaxy, which is suggested by the standard galaxy formation scenario. A numerical simulation (Tanikawa and Umemura, 2014) suggests that if the SMBH was formed by the merging process, then the dynamical friction caused by the black holes have influenced the phase space distribution of stars. The phase space distribution measured by SJ will make it possible to determine the occurrences of the merging process.

scholarly journals The distance to the Galactic Center

2012 ◽  
Vol 8 (S289) ◽  
pp. 29-35 ◽  
Author(s):  
Stefan Gillessen ◽  
Frank Eisenhauer ◽  
Tobias K. Fritz ◽  
Oliver Pfuhl ◽  
Thomas Ott ◽  
...  
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Distance Estimate ◽  
Massive Black Hole ◽  
Geometric Distance ◽  
Stellar Orbits ◽  
Fundamental Parameters ◽  
The Galaxy ◽  
Error Bars ◽  
Definition Of

AbstractOne of the Milky Way's fundamental parameters is the distance of the Sun from the Galactic Center, R0. This article reviews the various ways of estimating R0, placing special emphasis on methods that have become possible recently. In particular, we focus on the geometric distance estimate made possible thanks to observations of individual stellar orbits around the massive black hole at the center of the Galaxy. The specific issues of concern there are the degeneracies with other parameters, most importantly the mass of the black hole and the definition of the reference frame. The current uncertainty is nevertheless only a few percent, with error bars shrinking every year.

scholarly journals EXTENDED SUBMILLIMETER EMISSION OF THE GALACTIC CENTER AND NEAR-INFRARED/SUBMILLIMETER VARIABILITY OF ITS SUPERMASSIVE BLACK HOLE

2011 ◽  
Vol 738 (2) ◽  
pp. 158 ◽  
Author(s):  
M. García-Marín ◽  
A. Eckart ◽  
A. Weiss ◽  
G. Witzel ◽  
M. Bremer ◽  
...  
Keyword(s):  
Black Hole ◽  
Near Infrared ◽  
Galactic Center ◽  
Supermassive Black Hole ◽  
Submillimeter Emission

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

Science ◽  
2012 ◽  
Vol 338 (6103) ◽  
pp. 84-87 ◽  
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.

Infrared space astrometry mission for survey of the Galactic nuclear bulge: Small-JASMINE

2019 ◽  
Vol 14 (S353) ◽  
pp. 51-53
Author(s):  
Naoteru Gouda ◽  
Keyword(s):  
Black Hole ◽  
Near Infrared ◽  
Galactic Center ◽  
Scientific Objective ◽  
Satellite Mission ◽  
Infrared Band ◽  
Supermassive Black Hole ◽  
Space Astrometry ◽  
Galactic Structures ◽  
Astrometric Data

AbstractSmall-JASMINE will provide astrometric data with high precisions in a near infrared band for stars in the Galactic nuclear bulge and other specific targets. The primary scientific objective is to carry out the Galactic Center Archeology by exploring the Galactic nuclear bulge that leads to the elucidation of the Galactic structures and the evolution of the supermassive black hole at the center. Small-JASMINE has been selected as the unique candidate for the competitive 3rd M-class science satellite mission by ISAS/JAXA. The launch date is mid-2020s.

scholarly journals A geometric distance measurement to the Galactic center black hole with 0.3% uncertainty

2019 ◽  
Vol 625 ◽  
pp. L10 ◽  
Author(s):  
◽  
R. Abuter ◽  
A. Amorim ◽  
M. Bauböck ◽  
J. P. Berger ◽  
...  
Keyword(s):  
Black Hole ◽  
Near Infrared ◽  
Galactic Center ◽  
Accurate Determination ◽  
Massive Black Hole ◽  
Geometric Distance ◽  
Significance Level ◽  
Beam Combiner ◽  
Infrared Interferometry ◽  
Sgr A

We present a 0.16% precise and 0.27% accurate determination of R0, the distance to the Galactic center. Our measurement uses the star S2 on its 16-year orbit around the massive black hole Sgr A* that we followed astrometrically and spectroscopically for 27 years. Since 2017, we added near-infrared interferometry with the VLTI beam combiner GRAVITY, yielding a direct measurement of the separation vector between S2 and Sgr A* with an accuracy as good as 20 μas in the best cases. S2 passed the pericenter of its highly eccentric orbit in May 2018, and we followed the passage with dense sampling throughout the year. Together with our spectroscopy, in the best cases with an error of 7 km s−1, this yields a geometric distance estimate of R0 = 8178 ± 13stat. ± 22sys. pc. This work updates our previous publication, in which we reported the first detection of the gravitational redshift in the S2 data. The redshift term is now detected with a significance level of 20σ with fredshift = 1.04 ± 0.05.

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

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.

scholarly journals Observing AGN sources with the Event Horizon Telescope

2019 ◽  
Vol 15 (S356) ◽  
pp. 257-257
Author(s):  
Maciek Wielgus
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Angular Resolution ◽  
Galactic Center ◽  
Data Set ◽  
Supermassive Black Hole ◽  
History Of ◽  
Schwarzschild Radius ◽  
Centaurus A

AbstractIn April 2017 Event Horizon Telescope (EHT) has delivered first resolved images of a shadow of a supermassive black hole. Apart from black hole sources in M87 and in the Galactic Center, observed with resolution comparable to the Schwarzschild radius scale, EHT observed multiple AGN sources during the 2017 campaign. These include 3C279, Centaurus A, OJ287 and more. For most of the considered sources EHT 2017 data set should allow to reconstruct images with highest angular resolution in the history of their observations, approaching 20 uas. While the analysis of these data is still ongoing, I will talk about the scientific opportunities related to observing AGN sources with the extreme resolution of the EHT as well as about the astrophysical questions that these observations may help answering.

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