The central black hole in the Milky Way: the history of the Nobel Prize 2020

2021 ◽  
pp. 163-172
Author(s):  
O.K. Sil'chenko
Keyword(s):  
Black Hole ◽  
Nobel Prize ◽  
Milky Way ◽  
Central Black Hole ◽  
History Of

scholarly journals The Milky Way’s nuclear star cluster: Old, metal-rich, and cuspy

2020 ◽  
Vol 641 ◽  
pp. A102 ◽  
Author(s):  
R. Schödel ◽  
F. Nogueras-Lara ◽  
E. Gallego-Cano ◽  
B. Shahzamanian ◽  
A. T. Gallego-Calvente ◽  
...  
Keyword(s):  
Black Hole ◽  
Star Formation ◽  
Milky Way ◽  
Star Cluster ◽  
Star Formation History ◽  
Central Black Hole ◽  
Formation History ◽  
History Of ◽  
Nuclear Cluster ◽  
Sgr A

Context. The environment of Sagittarius A* (Sgr A*), the central black hole of the Milky Way, is the only place in the Universe where we can currently study the interaction between a nuclear star cluster and a massive black hole and infer the properties of a nuclear cluster from observations of individual stars. Aims. This work aims to explore the star formation history of the nuclear cluster and the structure of the innermost stellar cusp around Sgr A*. Methods. We combined and analysed multi epoch high quality AO observations. For the region close to Sgr A* we apply the speckle holography technique to the AO data and obtain images that are ≥50% complete down to Ks ≈ 19 within a projected radius of 5″ around Sgr A*. We used H-band images to derive extinction maps. Results. We provide Ks photometry for roughly 39 000 stars and H-band photometry for ∼11 000 stars within a field of about 40″ × 40″, centred on Sgr A*. In addition, we provide Ks photometry of ∼3000 stars in a very deep central field of 10″ × 10″, centred on Sgr A*. We find that the Ks luminosity function (KLF) is rather homogeneous within the studied field and does not show any significant changes as a function of distance from the central black hole on scales of a few 0.1 pc. By fitting theoretical luminosity functions to the KLF, we derive the star formation history of the nuclear star cluster. We find that about 80% of the original star formation took place 10 Gyr ago or longer, followed by a largely quiescent phase that lasted for more than 5 Gyr. We clearly detect the presence of intermediate-age stars of about 3 Gyr in age. This event makes up about 15% of the originally formed stellar mass of the cluster. A few percent of the stellar mass formed in the past few 100 Myr. Our results appear to be inconsistent with a quasi-continuous star formation history. The mean metallicity of the stars is consistent with being slightly super solar. The stellar density increases exponentially towards Sgr A* at all magnitudes between Ks = 15−19. We also show that the precise properties of the stellar cusp around Sgr A* are hard to determine because the star formation history suggests that the star counts can be significantly contaminated, at all magnitudes, by stars that are too young to be dynamically relaxed. We find that the probability of observing any young (non-millisecond) pulsar in a tight orbit around Sgr A* and beamed towards Earth is very low. We argue that typical globular clusters, such as they are observed in and around the Milky Way today, have probably not contributed to the nuclear cluster’s mass in any significant way. The nuclear cluster may have formed following major merger events in the early history of the Milky Way.

scholarly journals A Multi-Frequency Study of the Milky Way-Like Spiral Galaxy NGC 6744

2018 ◽  
Vol 35 ◽  
Author(s):  
Miranda Yew ◽  
Miroslav D. Filipović ◽  
Quentin Roper ◽  
Jordan D. Collier ◽  
Evan J. Crawford ◽  
...  
Keyword(s):  
Black Hole ◽  
Milky Way ◽  
Formation Rate ◽  
Radio Continuum ◽  
Starburst Galaxy ◽  
Radio Sources ◽  
Wide Field ◽  
Central Black Hole ◽  
X Ray ◽  
Continuum Data

AbstractWe present a multi-frequency study of the intermediate spiral SAB(r)bc type galaxy NGC 6744, using available data from the Chandra X-Ray telescope, radio continuum data from the Australia Telescope Compact Array and Murchison Widefield Array, and Wide-field Infrared Survey Explorer infrared observations. We identify 117 X-ray sources and 280 radio sources. Of these, we find nine sources in common between the X-ray and radio catalogues, one of which is a faint central black hole with a bolometric radio luminosity similar to the Milky Way’s central black hole. We classify 5 objects as supernova remnant (SNR) candidates, 2 objects as likely SNRs, 17 as H ii regions, 1 source as an AGN; the remaining 255 radio sources are categorised as background objects and one X-ray source is classified as a foreground star. We find the star-formation rate (SFR) of NGC 6744 to be in the range 2.8–4.7 M⊙~yr − 1 signifying the galaxy is still actively forming stars. The specific SFR of NGC 6744 is greater than that of late-type spirals such as the Milky Way, but considerably less that that of a typical starburst galaxy.

scholarly journals 10.2. High proper motions in the vicinity of Sgr A∗: unambiguous evidence for a massive central black hole

1998 ◽  
Vol 184 ◽  
pp. 433-434
Author(s):  
A. M. Ghez ◽  
B. L. Klein ◽  
C. McCabe ◽  
M. Morris ◽  
E. E. Becklin
Keyword(s):  
Black Hole ◽  
Milky Way ◽  
Galactic Center ◽  
Robust Method ◽  
Proper Motions ◽  
Central Black Hole ◽  
Milky Way Galaxy ◽  
The Galaxy ◽  
Sgr A

Although the notion that the Milky Way galaxy contains a supermassive central black hole has been around for more than two decades, it has been difficult to prove that one exists. The challenge is to assess the distribution of matter in the few central parsecs of the Galaxy. Assuming that gravity is the dominant force, the motion of the stars and gas in the vicinity of the putative black hole offers a robust method for accomplishing this task, by revealing the mass interior to the radius of the objects studied. Thus objects located closest to the Galactic Center provide the strongest constraints on the black hole hypothesis.

scholarly journals The Habitability of the Galactic Bulge

Life ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 132
Author(s):  
Amedeo Balbi ◽  
Maryam Hami ◽  
Andjelka Kovačević
Keyword(s):  
Black Hole ◽  
Milky Way ◽  
Orbital Stability ◽  
Analytical Models ◽  
Radiation Environment ◽  
Habitable Zone ◽  
Central Black Hole ◽  
Supermassive Black Hole ◽  
Star Density ◽  
Rocky Planets

We present a new investigation of the habitability of the Milky Way bulge, that expands previous studies on the Galactic Habitable Zone. We discuss existing knowledge on the abundance of planets in the bulge, metallicity and the possible frequency of rocky planets, orbital stability and encounters, and the possibility of planets around the central supermassive black hole. We focus on two aspects that can present substantial differences with respect to the environment in the disk: (i) the ionizing radiation environment, due to the presence of the central black hole and to the highest rate of supernovae explosions and (ii) the efficiency of putative lithopanspermia mechanism for the diffusion of life between stellar systems. We use analytical models of the star density in the bulge to provide estimates of the rate of catastrophic events and of the diffusion timescales for life over interstellar distances.

scholarly journals The Milky Way's nuclear star cluster and massive black hole

2014 ◽  
Vol 10 (S312) ◽  
pp. 274-281
Author(s):  
Rainer Schödel
Keyword(s):  
Black Hole ◽  
Milky Way ◽  
Current Knowledge ◽  
Star Cluster ◽  
Kinematics And Dynamics ◽  
Central Black Hole ◽  
Massive Black Hole ◽  
Sagittarius A ◽  
Concise Overview ◽  
Galaxy Nucleus

AbstractBecause of its nearness to Earth, the centre of the Milky Way is the only galaxy nucleus in which we can study the characteristics, distribution, kinematics, and dynamics of the stars on milli-parsec scales. We have accurate and precise measurements of the Galactic centre's central black hole, Sagittarius A*, and can study its interaction with the surrounding nuclear star cluster in detail. This contribution aims at providing a concise overview of our current knowledge about the Milky Way's central black hole and nuclear star cluster, at highlighting the observational challenges and limitations, and at discussing some of the current key areas of investigation.

Journeying Through the Black Hole of Recycling

ITNOW ◽  
2019 ◽  
Vol 61 (4) ◽  
pp. 24-25
Author(s):  
Johanna Hamilton
Keyword(s):  
Black Hole ◽  
Nobel Prize ◽  
Senior Lecturer ◽  
Safety Research ◽  
History Of ◽  
Rich History ◽  
Research Institute

Abstract UK universities have a rich history of leading groundbreaking projects, spanning Nobel Prize winning discoveries, medicines and inventions. Standing on the shoulders of giants, Dr Alvin Orbaek White, Senior Lecturer and Sêr Cymru II Fellow at the Energy Safety Research Institute at Swansea University, tells Johanna Hamilton AMBCS how his findings could plug a recycling black hole.

scholarly journals Spectroscopic Detection of a Cusp of Late-type Stars around the Central Black Hole in the Milky Way

2019 ◽  
Vol 872 (1) ◽  
pp. L15 ◽  
Author(s):  
M. Habibi ◽  
S. Gillessen ◽  
O. Pfuhl ◽  
F. Eisenhauer ◽  
P. M. Plewa ◽  
...  
Keyword(s):  
Black Hole ◽  
Milky Way ◽  
Late Type ◽  
Central Black Hole
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