scholarly journals Examining molecular clouds in the Galactic Centre region using X-ray reflection spectra simulations

2016 ◽  
Vol 463 (3) ◽  
pp. 2893-2903 ◽  
Author(s):  
M. Walls ◽  
M. Chernyakova ◽  
R. Terrier ◽  
A. Goldwurm
Keyword(s):  
Molecular Clouds ◽  
Galactic Centre ◽  
Reflection Spectra ◽  
X Ray ◽  
Centre Region

scholarly journals Cosmic Rays in the Galactic Centre

1980 ◽  
Vol 33 (1) ◽  
pp. 115
Author(s):  
Masato Yoshimori
Keyword(s):  
Energy Density ◽  
Cosmic Rays ◽  
Solar System ◽  
Molecular Clouds ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Centre ◽  
Centre Region ◽  
Cosmic Ray Flux

The cosmic ray flux in the galactic centre region is predicted from the observed data for high energy y rays, y-ray lines and massive molecular clouds. The predicted cosmic ray fluxes above 1 GeVand below 100 MeV are two and four orders of magnitude respectively larger than the value in the neighbourhood of the solar system. The corresponding energy density of cosmic rays is estimated to be 100 eV cm- 3 ? Such a concentrated stream of cosmic rays could accelerate the dense and massive molecular clouds by transfer of their momentum.

scholarly journals A Survey of OH in the Galactic Centre Region

1996 ◽  
Vol 169 ◽  
pp. 311-316
Author(s):  
P.J. Boyce ◽  
R. J. Cohen
Keyword(s):  
Central Region ◽  
Molecular Clouds ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Molecular Gas ◽  
The Galaxy ◽  
Centre Region ◽  
Line Survey ◽  
The Continuum

The galactic centre contains the largest concentration of molecular clouds in the Galaxy. The clouds in the central region are unusual in having large linewidths and masses, and large non-circular motions. Previous surveys of their distribution in the central region have been carried out in OH (Robinson & McGee 1970; Cohen & Few 1976), H2CO (Whiteoak & Gardner 1979; Cohen & Few 1981), CO (Bania 1977; Dame et al. 1987; Bally et al. 1987, 1988) and CS (Bally et al. 1987, 1988). The OH groundstate lines at 18cm wavelength have certain advantages for such a survey. The OH lines appear in absorption against the galactic centre continuum sources, and against the continuum emission from the disk of the Galaxy. The absorption spectra are sensitive to relatively small molecular column densities. In addition they can give information on the relative positions of the molecular gas and the radio continuum sources. This paper describes results from an absorption line survey of the galactic centre region in the OH main lines at 1667.359 MHz and 1665.402 MHz (Boyce & Cohen 1994).

scholarly journals X-Ray Observations of the Galactic Centre

1989 ◽  
Vol 136 ◽  
pp. 567-580 ◽  
Author(s):  
G. K. Skinner
Keyword(s):  
Energy Range ◽  
High Energy ◽  
Point Sources ◽  
Galactic Centre ◽  
X Rays ◽  
Diffuse Emission ◽  
Variable Source ◽  
X Ray ◽  
Centre Region ◽  
Sgr A

Observations of the galactic centre region in the photon energy range 2–500 keV are reviewed. Point sources, transients, bursts and a patch of apparently diffuse emission ~1° in extent have all been observed. The relatively detailed information obtained with the Einstein observatory just above the bottom edge of the x-ray window is starting to be supplemented by observations at higher photon energies. Although there is known to be a strong, variable, source of high energy x-rays somewhere in the region there is little reason to associate it with Sgr A West, which is detectable, but relatively weak, in the energy range below 30 keV where detailed measurements have been possible.

scholarly journals Broadband X-ray analysis of 1E 1740.7−2942: constraints on spin, inclination, and a tentative black hole mass

2020 ◽  
Vol 493 (2) ◽  
pp. 2694-2705 ◽  
Author(s):  
Paulo E Stecchini ◽  
F D’Amico ◽  
F Jablonski ◽  
M Castro ◽  
J Braga
Keyword(s):  
Black Hole ◽  
High Mass ◽  
Joint Analysis ◽  
Maximum Speed ◽  
Galactic Centre ◽  
X Rays ◽  
Black Hole Mass ◽  
X Ray ◽  
Centre Region ◽  
Reflection Component

ABSTRACT 1E 1740.7−2942 is one of the strongest hard X-ray emitters in the Galactic Centre region, believed to be a black hole in a high-mass X-ray binary system. Although extensively studied in X-rays, many aspects about the underlying nature of the system are still unknown. For example, X-ray data analyses of 1E 1740.7−2942 to date have not yet unveiled the signature of a reflection component, whose modelling could be used to estimate parameters such as the spin of the black hole and inclination of the disc. We report here on the determination of these parameters from the analysis of the reflection component present in a public NuSTAR observation which has not been subject to any previous study. We include XMM–Newton and INTEGRAL data to build a combined spectrum, enabling a joint analysis of both the disc and comptonization components. Results point to a relatively high inclination disc ≳ 50° (3 σ) and a near-maximum speed rotating black hole. The former is in agreement with a previous radio study and the latter is reported here for the first time. Lastly, we follow the methodology of recent efforts to weigh black holes with only X-ray spectra and find results that suggest a black hole mass of about 5 M⊙ for 1E 1740.7−2942.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

Progress report on 21-cm observations at low latitude between longitudes (l 11) 0° and 66°

1967 ◽  
Vol 31 ◽  
pp. 177-179
Author(s):  
W. W. Shane
Keyword(s):  
Preliminary Report ◽  
Progress Report ◽  
Galactic Centre ◽  
Low Latitude ◽  
The Third ◽  
Introductory Lecture ◽  
Centre Region

In the course of several 21-cm observing programmes being carried out by the Leiden Observatory with the 25-meter telescope at Dwingeloo, a fairly complete, though inhomogeneous, survey of the regionl11= 0° to 66° at low galactic latitudes is becoming available. The essential data on this survey are presented in Table 1. Oort (1967) has given a preliminary report on the first and third investigations. The third is discussed briefly by Kerr in his introductory lecture on the galactic centre region (Paper 42). Burton (1966) has published provisional results of the fifth investigation, and I have discussed the sixth in Paper 19. All of the observations listed in the table have been completed, but we plan to extend investigation 3 to a much finer grid of positions.

Observations of the continuum near the galactic centre

1967 ◽  
Vol 31 ◽  
pp. 405
Author(s):  
F. J. Kerr
Keyword(s):  
Galactic Centre ◽  
The Past ◽  
Centre Region ◽  
The Continuum

A continuum survey of the galactic-centre region has been carried out at Parkes at 20 cm wavelength over the areal11= 355° to 5°,b11= -3° to +3° (Kerr and Sinclair 1966, 1967). This is a larger region than has been covered in such surveys in the past. The observations were done as declination scans.

scholarly journals Exploring a New Population of Compact Objects: X-ray and IR Observations of the Galactic Centre

2008 ◽  
Author(s):  
Reba M. Bandyopadhyay ◽  
Andrew J. Gosling ◽  
Stephen E. Eikenberry ◽  
Michael P. Muno ◽  
Katherine M. Blundell ◽  
...  
Keyword(s):  
Compact Objects ◽  
Galactic Centre ◽  
X Ray
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