Orbits

2018 ◽  
Author(s):  
Prasenjit Saha ◽  
Paul A. Taylor
Keyword(s):  
Black Hole ◽  
Arbitrary Number ◽  
Virial Theorem ◽  
Milky Way ◽  
Extrasolar Planets ◽  
Newtonian Gravity ◽  
Kepler's Laws ◽  
Gravitational Capture ◽  
Two Bodies ◽  
Modern Perspective

Astronomy and recording of the motion of celestial objects are ancient practices, but what is now called astrophysics arguably began with Newtonian gravity and the concept of orbits as dynamical phenomena. This chapter provides a modern perspective on the early problems of gravitational dynamics, from Kepler’s laws up to the virial theorem for an arbitrary number of gravitating bodies. Even a simple gravitating system with only two bodies turns out to have many interesting features, such as the gravitational capture of material by protoplanets. The study of orbital motions also includes applications to observing extrasolar planets and stars near the black hole at the centre of the Milky Way.

scholarly journals X-Ray Determination of the Black-Hole Mass in Cygnus X-1

1998 ◽  
Vol 188 ◽  
pp. 388-389
Author(s):  
A. Kubota ◽  
K. Makishima ◽  
T. Dotani ◽  
H. Inoue ◽  
K. Mitsuda ◽  
...  
Keyword(s):  
Black Hole ◽  
Compact Object ◽  
Optical Observations ◽  
Black Hole Mass ◽  
X Ray ◽  
Upper Limit ◽  
Supergiant Star ◽  
X Ray Binaries ◽  
Two Bodies

About 10 X-ray binaries in our Galaxy and LMC/SMC are considered to contain black hole candidates (BHCs). Among these objects, Cyg X-1 was identified as the first BHC, and it has led BHCs for more than 25 years(Oda 1977, Liang and Nolan 1984). It is a binary system composed of normal blue supergiant star and the X-ray emitting compact object. The orbital kinematics derived from optical observations indicates that the compact object is heavier than ~ 4.8 M⊙ (Herrero 1995), which well exceeds the upper limit mass for a neutron star(Kalogora 1996), where we assume the system consists of only two bodies. This has been the basis for BHC of Cyg X-1.

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.

Does the Milky Way Hide Its Black Hole?

Science News ◽  
1995 ◽  
Vol 147 (15) ◽  
pp. 230
Author(s):  
J. Kaiser
Keyword(s):  
Black Hole ◽  
Milky Way

scholarly journals MILKY WAY GLOBULAR CLUSTERS: CLOSE ENCOUNTER RATES WITH EACH OTHER AND WITH THE CENTRAL SUPERMASSIVE BLACK HOLE

REPORTS ◽  
2021 ◽  
Vol 6 (340) ◽  
pp. 94-105
Author(s):  
M.V. Ishchenko ◽  
M.O. Sobolenko ◽  
M.T. Kalambay ◽  
B.T. Shukirgaliyev ◽  
P.P. Berczik
Keyword(s):  
Black Hole ◽  
Globular Clusters ◽  
Milky Way ◽  
Close Encounter ◽  
Encounter Rates ◽  
Supermassive Black Hole

scholarly journals The Potential for Archaeology Within and Beyond the Habitable Zones (HZ) of the Milky Way

2004 ◽  
Vol 213 ◽  
pp. 505-510
Author(s):  
John B. Campbell
Keyword(s):  
Remote Sensing ◽  
Solar System ◽  
Milky Way ◽  
Extrasolar Planets ◽  
Habitable Zone ◽  
The Moon ◽  
Habitable Zones ◽  
Remote Sensing Techniques ◽  
Main Region

As archaeology is established on Earth and we are actively exploring the Solar System and beyond, there is the potential to develop a number of forms of exo-archaeology. The archaeology of the things intelligent species do in theory could be practised anywhere, provided one can detect the evidence. Sites are being created by us elsewhere within our star's habitable zone (HZ), namely on the Moon and Mars, and at least molecular traces of human-created probes are being left beyond the HZ (Venus, Jupiter etc.). The successful detection of extrasolar planets and the possible identification of HZs round other stars raise the possibility for the development of extrasolar archaeology, at least initially by remote sensing techniques. Within the Milky Way the main region to investigate is the galactic habitable zone (GHZ), though there could be archaeological traces of technological behaviours beyond it.

scholarly journals Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way

2004 ◽  
Vol 601 (2) ◽  
pp. L159-L162 ◽  
Author(s):  
A. M. Ghez ◽  
S. A. Wright ◽  
K. Matthews ◽  
D. Thompson ◽  
D. Le Mignant ◽  
...  
Keyword(s):  
Black Hole ◽  
Milky Way ◽  
Infrared Emission ◽  
Supermassive Black Hole
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