The Dark Mass Concentration in the Central Parsec of the Milky Way

Genzel, R.; Thatte, Niranjan; Krabbe, A.; Kroker, H.; Tacconi-Garman, L. E.

doi:10.1086/178051

Cited by 318 publications

(525 citation statements)

References 14 publications

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“…The kinematics of the central star cluster probes the gravitational potential within a mere 0.015 pc of the nucleus and reveals the presence of of dark matter in this 6 2.6 # 10 M , region (Genzel et al 1997;Ghez et al 1998). Several alternative scenarios invoked to explain this condensation of matter have been excluded with a high degree of confidence (Haller et al 1996;Genzel et al 1996;Melia & Coker 1999).…”

Section: Introductionmentioning

confidence: 96%

Polarimetric Imaging of the Massive Black Hole at the Galactic Center

Bromley

Melia

Liu

2001

The Astrophysical Journal

118

115

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The radio source Sagittarius A* in the Galactic center emits a polarized spectrum at millimeter and submillimeter wavelengths that is strongly suggestive of relativistic disk accretion onto a massive black hole. We use the wellconstrained mass of Sgr A* and a magnetohydrodynamic model of the accretion flow to match both the total flux and polarization from this object. Our results demonstrate explicitly that the shift in the position angle of the polarization vector, seen at wavelengths near the peak of the millimeter to submillimeter emission from this source, is a signal of relativistic accretion flow in a strong gravitational field. We provide maps of the polarized emission to illustrate how the images of polarized intensity from the vicinity of the black hole would appear in upcoming observations with very long baseline radio interferometers (VLBIs). Our results suggest that near-term VLBI observations will be able to directly image the polarized Keplerian portion of the flow near the horizon of the black hole.

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Section: Introductionmentioning

confidence: 96%

Polarimetric Imaging of the Massive Black Hole at the Galactic Center

Bromley

Melia

Liu

2001

The Astrophysical Journal

118

115

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“…Due to its proximity, individual stars can be resolved and c 2002 RAS number counts can be derived; however, due to the strong interstellar extinction the stars can only be observed in the infrared. A large number of proper motions and line-of-sight velocities have been measured, and analyzed with spherical models to attempt to constrain the NSC dynamics and mass (Haller et al 1996;Genzel et al 1996Genzel et al , 2000Trippe et al 2008;Schödel et al 2009;Fritz et al 2014).…”

Section: Introductionmentioning

confidence: 99%

The old nuclear star cluster in the Milky Way: dynamics, mass, statistical parallax, and black hole mass

Chatzopoulos¹,

Fritz²,

Gerhard³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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171

218

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We derive new constraints on the mass, rotation, orbit structure and statistical parallax of the Galactic old nuclear star cluster and the mass of the supermassive black hole. We combine star counts and kinematic data from Fritz et al. (2014), including 2'500 line-of-sight velocities and 10'000 proper motions obtained with VLT instruments. We show that the difference between the proper motion dispersions σ l and σ b cannot be explained by rotation, but is a consequence of the flattening of the nuclear cluster. We fit the surface density distribution of stars in the central 1000 ′′ by a superposition of a spheroidal cluster with scale ∼ 100 ′′ and a much larger nuclear disk component. We compute the self-consistent two-integral distribution function f (E, L z ) for this density model, and add rotation self-consistently. We find that: (i) The orbit structure of the f (E, L z ) gives an excellent match to the observed velocity dispersion profiles as well as the proper motion and line-of-sight velocity histograms, including the double-peak in the v l -histograms. (ii) This requires an axial ratio near q 1 = 0.7 consistent with our determination from star counts, q 1 = 0.73 ± 0.04 for r < 70 ′′ . (iii) The nuclear star cluster is approximately described by an isotropic rotator model. (iv) Using the corresponding Jeans equations to fit the proper motion and line-of-sight velocity dispersions, we obtain best estimates for the nuclear star cluster mass, black hole mass, and distance M * (r < 100 ′′ ) = (8.94±0.31| stat ±0.9| syst )×10 6 M ⊙ , M • = (3.86±0.14| stat ±0.4| syst )×10 6 M ⊙ , and R 0 = 8.27±0.09| stat ±0.1| syst kpc, where the estimated systematic errors account for additional uncertainties in the dynamical modeling. (v) The combination of the cluster dynamics with the S-star orbits around Sgr A * strongly reduces the degeneracy between black hole mass and Galactic centre distance present in previous S-star studies. A joint statistical analysis with the results of Gillessen et al. (2009) gives M • = (4.23±0.14)×10 6 M ⊙ and R 0 = 8.33±0.11 kpc.

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“…Light-blue, filled rectangles are mass estimates from a parameterized Jeans-equation model, including anisotropy and distinguishing between late and early type stars (Genzel et al 2000). Open circles are mass estimates from a parameterized Jeans-equation model of the radial velocities of late type stars, assuming isotropy (Genzel et al 1996). Open red rectangles denote mass estimates from a non-parametric, maximum likelihood model, assuming isotropy and combining late and early type stars (Chakrabarty and Saha 2001).…”

Section: Nature Of the Enclosed Massmentioning

confidence: 99%

The Galactic Center stellar cluster: The central arcsecond

et al. 2003

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With 10 years of high-resolution imaging data now available on the stellar cluster in the Galactic Center, we analyze the dynamics of the stars at projected distances $\leq1.2''$ from the central black hole candidate Sagittarius A* (Sgr A*). We find evidence for radial anisotropy of the cluster of stars surrounding Sgr A*. We confirm/find accelerated motion for 6 stars, with 4 stars having passed the pericenter of their orbits during the observed time span. We calculated/constrained the orbital parameters of these stars. All orbits have moderate to high eccentricities. The center of acceleration coincides with the radio position of Sgr A*. From the orbit of the star S2, the currently most tightly constrained one, we determine the mass of Sgr A* to $3.3\pm0.7\times10^{6}$M$_{\odot}$ and its position to $2.0\pm2.4$ mas East and $2.7\pm4.5$ mas South of the nominal radio position. The data provide compelling evidence that Sgr A* is a single supermassive black hole.Comment: 7 pages, 3 Figures; to be published in Astron. Nachr., Vol. 324, No. S1 (2003), Special Supplement "The central 300 parsecs of the Milky Way", Eds. A. Cotera, H. Falcke, T. R. Geballe, S. Markof

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The Dark Mass Concentration in the Central Parsec of the Milky Way

Cited by 318 publications

References 14 publications

Polarimetric Imaging of the Massive Black Hole at the Galactic Center

Polarimetric Imaging of the Massive Black Hole at the Galactic Center

The old nuclear star cluster in the Milky Way: dynamics, mass, statistical parallax, and black hole mass

The Galactic Center stellar cluster: The central arcsecond

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