The galactic center massive black hole and nuclear star cluster

By R. Genzel, F. Eisenhauer, S. Gillessen. 2010

799 citations recorded by the source corpus.

The Galactic Center is an excellent laboratory for studying phenomena and physical processes that may be occurring in many other galactic nuclei. The Center of our Milky Way is by far the closest galactic nucleus, and observations with exquisite resolution and sensitivity cover 18 orders of magnitude in energy of electromagnetic radiation. Theoretical simulations have become increasingly more powerful in explaining these measurements. This review summarizes the recent progress in observational and theoretical work on the central parsec, with a strong emphasis on the current empirical evidence for a central massive black hole and on the processes in the surrounding dense nuclear star cluster. We present the current evidence, from the analysis of the orbits of more than two dozen stars and from the measurements of the size and motion of the central compact radio source, Sgr A*, that this radio source must be a massive black hole of about 4.4 \times 1e6 Msun, beyond any reasonable doubt. We report what is known about the structure and evolution of the dense nuclear star cluster surrounding this black hole, including the astounding fact that stars have been forming in the vicinity of Sgr A* recently, apparently with a top-heavy stellar mass function. We discuss a dense concentration of fainter stars centered in the immediate vicinity of the massive black hole, three of which have orbital peri-bothroi of less than one light day. This 'S-star cluster' appears to consist mainly of young early-type stars, in contrast to the predicted properties of an equilibrium 'stellar cusp' around a black hole. This constitutes a remarkable and presently not fully understood 'paradox of youth'. We also summarize what is known about the emission properties of the accreting gas onto Sgr A* and how this emission is beginning to delineate the physical properties in the hot accretion zone around the event horizon.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/9d04e3f969aadbd29ce293fb72dbbf66f17729b3

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. P. Hopkins
2. L. Hernquist
3. R. Genzel
4. F. Antonini
5. M. Volonteri
6. Volker Springel
7. T. Naab
8. E. Quataert

In Nuclear and High Energy Physics

1. A. Strong
2. E. Orlando
3. Ramesh Narayan
4. V. Cardoso
5. F. Yuan
6. I. Grenier
7. Bing Zhang
8. Lavinia Heisenberg

Citations in the corpus

• Numerical simulations of the dark universe: State of the art and the next decade (2012, background): “Unfortunately, the GC is also an extraordinarily astrophysically active place [100] hosting numerous SN remnants, pulsars, X-ray binaries, and other high-energy sources, not to mention a super-massive black hole.”
• Observational Signatures of Particle Acceleration in Supernova Remnants (2012, background): “Finally at the very center, the faint source Sgr A?, is powered by a supermassive black hole of 4 106 M (Genzel et al., 2010, and references therein).”
• Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole (2018, background): “Radio and infrared observations have provided detailed information on the distribution, kinematics, and physical properties of this nuclear star cluster and of the hot, warm, and cold interstellar gas interspersed in it (cf. Genzel et al. 2010; Morris et al. 2012; Falcke & Markoff 2013).”
• Born–Infeld inspired modifications of gravity (2017, background): “4× 10(6)M⊙, corresponding to the supermassive black hole at the centre of the Milky Way [176].”
• Doing Science with eLISA: Astrophysics and Cosmology in the Millihertz Regime (2012, methodology): “Overall, the measurements at the Galactic Centre are consistent with a system composed of a massive black hole and an extended close-to-isotropic star cluster, with the young S0 (or S) stars the only population showing a collective rotation pattern in their orbits (Genzel et al., 2010).”
• On the charge of the Galactic centre black hole (2018, background): “…Galactic centre across the electromagnetic spectrum, ranging from radio to gamma wavelengths, revealed the complex structure of the Nuclear Star Cluster (NSC) as well as that of the gaseous-dusty medium of the central parsec (Eckart et al. 2005; Melia 2007; Genzel et al. 2010; Eckart et al. 2017).”
• A geometric distance measurement to the Galactic center black hole with 0.3% uncertainty (2019, background): “L10, page 1 of 10 general recent overviews of R0 determinations, see Genzel et al. (2010) and Bland-Hawthorn & Gerhard (2016).”
• Detection of orbital motions near the last stable circular orbit of the massive black hole SgrA* (2018, background): “SgrA* exhibits steady and continuously variable, non-thermal emission across the electromagnetic spectrum (Genzel et al. 2010; Baganoff et al. 2001; Trippe et al. 2007; Eckart et al. 2008; Yusef-Zadeh et al. 2008; Do et al. 2009; Dodds-Eden et al. 2009; Shahzamanian et al. 2015; Ponti et al. 2017;…”
• LINE DERIVED INFRARED EXTINCTION TOWARD THE GALACTIC CENTER (2011, background): “Our result is also consistent with the review of Reid (1993), who determined R0 = 8.0 ± 0.5 kpc, and the recent review of Genzel et al. (2010), who determined R0 = 8.15 ± 0.14 ± 0.35 kpc from direct and indirect measurements, and R0 = 8.23± 0.2± 0.19 kpc from only direct measurements.”
• SECULAR EVOLUTION OF COMPACT BINARIES NEAR MASSIVE BLACK HOLES: GRAVITATIONAL WAVE SOURCES AND OTHER EXOTICA (2012, background): “These stars were most likely to form in-situ following the fragmentation of a gaseous disk formed from an in-falling gaseous clump (Genzel et al. 2010, and references therein).”
• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies (2013, methodology): “To get MKsT = −23.7, we adopt the total K-band luminosity LK = 6.7× 10 10 LK⊙ from Kent, Dame & Fazio (1991) and convert it from their assumed distance of 8 kpc to our assumed distance of 8.28 kpc from Genzel et al. (2010).”
• Surface brightness profile of the Milky Way’s nuclear star cluster (2014, background): “It is thus a crucial laboratory for studying galactic nuclei (Ghez et al. 2009; Genzel et al. 2010; Schödel 2011).”
• FERMI-LAT OBSERVATIONS OF HIGH-ENERGY γ-RAY EMISSION TOWARD THE GALACTIC CENTER (2015, background): “The GC also houses a ∼ 106 M black hole (e.g., Genzel et al. 2010) and the region is predicted to be the brightest source of γ-rays associated with annihilation or decay of massive 9 Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy 10 Istituto Nazionale di Fisica…”
• An Update on Monitoring Stellar Orbits in the Galactic Center (2016, background): “25 years of near-infrared observations of the Galactic Center have shown that a wealth of fundamental astrophysical and physical questions can be addressed with these measurements, ranging from star formation, to stellar dynamics, to testing general relativity (Genzel et al. 2010).”