The Origin of X-Ray Emission from a Galactic Center Molecular Cloud: Low-Energy Cosmic-Ray Electrons

2002 ◽  
Vol 568 (2) ◽  
pp. L121-L125 ◽  
Author(s):  
F. Yusef-Zadeh ◽  
C. Law ◽  
M. Wardle
Keyword(s):  
Molecular Cloud ◽  
Galactic Center ◽  
Cosmic Ray ◽  
Low Energy ◽  
X Ray

scholarly journals Diffusion of cosmic-ray electrons in the Galactic centre molecular cloud G0.13–0.13

2013 ◽  
Vol 9 (S303) ◽  
pp. 434-438
Author(s):  
Andrew Lehmann ◽  
Mark Wardle
Keyword(s):  
Molecular Cloud ◽  
Galactic Center ◽  
Galactic Disk ◽  
Line Emission ◽  
Cosmic Ray ◽  
Diffusion Models ◽  
Low Energy ◽  
Shell Morphology ◽  
Galactic Centre ◽  
Heating Rates

AbstractThe Galactic center (GC) molecular cloud G0.13–0.13 exhibits a shell morphology in CS J = (1 − 0), with ∼ 105 solar masses and expansion speed ∼ 20 km s−1, yielding a total kinetic energy ∼ 1051 erg. Its morphology is also suggestive of an interaction with the nonthermal filaments of the GC arc. 74 MHz emission indicates the presence of a substantial population of low energy electrons permeating the cloud, which could either be produced by the interaction with the arc or accelerated in the shock waves responsible for the cloud's expansion. These scenarios are explored using time dependent diffusion models.With these diffusion models, we determine the penetration of low-energy cosmic-ray electrons accelerated into G0.13–0.13 and calculate the spatial distribution of the cosmic-ray ionization and heating rates. We show that the 6.4 keV Fe Kα line emission associated with the electron population provides an observational diagnostic to distinguish these two acceleration scenarios.We discuss the implications of our results for understanding the distinct character of clouds in the central molecular zone compared to clouds in the Galactic disk, and how GC nonthermal filaments interact with molecular clouds.

scholarly journals Low Energy Galactic Center Gamma Rays from Low Mass X-Ray Binaries

1989 ◽  
Vol 136 ◽  
pp. 627-632
Author(s):  
W. Kluźniak ◽  
M. Ruderman ◽  
J. Shaham ◽  
M. Tavani
Keyword(s):  
Positron Annihilation ◽  
Power Law ◽  
Galactic Center ◽  
Low Energy ◽  
Continuum Emission ◽  
Relativistic Electrons ◽  
X Ray ◽  
Electron Positron ◽  
Low Mass ◽  
X Ray Binaries

The hard X-ray and low energy γ-ray emission from the galactic center region (GCR) has four components: a power-law continuum between 20/50 keV and 200/300 keV with a power-law photon index β in the range ~ 2.5 to ~ 3.1; a harder spectrum with β ~ 1.–1.5 between 200/300 keV and ~ 511 keV; a narrow electron-positron annihilation line at 511 keV, reported to disappear in less than < 1/2 yr, although the temporal variation is controversial; and an equally variable continuum emission between 511 keV and several MeV (“MeV bump”). All four have luminosities 1037–1038 erg s−1, if they are located 10 kpc away. We propose non-thermal processes in low mass X-ray binaries (LMXB's) concentrated in the galactic bulge as the direct source of the three continuum components of the emission, as well as of an escaping electron-positron e± wind whose positron annihilation relatively far from the star could be the source of the 511 keV line. We consider a model for energetic emission from LMXB's that reproduces the softer power-law component of the GCR continuum through synchrotron emission of relativistic electrons in the strongly non-uniform (dipolar) magnetic field of the neutron star. We also explain, with less confidence, the variable MeV bump as the result of interaction of harder γ-rays with the power-law photons. The harder power law might be due to Compton scattering of relativistic electrons or photons.

scholarly journals Cosmic-Ray Production and X-Ray and Gamma-Ray Emission from the Galactic Center

2009 ◽  
Vol 78 (Suppl.A) ◽  
pp. 133-137
Author(s):  
V. A. Dogiel ◽  
K.-S. Cheng ◽  
D. O. Chernyshov ◽  
V. Tatischeff ◽  
C.-M. Ko ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Galactic Center ◽  
Cosmic Ray ◽  
X Ray ◽  
Gamma Ray Emission

scholarly journals HARD X-RAY MORPHOLOGICAL AND SPECTRAL STUDIES OF THE GALACTIC CENTER MOLECULAR CLOUD SGR B2: CONSTRAINING PAST SGR A⋆ FLARING ACTIVITY

2015 ◽  
Vol 815 (2) ◽  
pp. 132 ◽  
Author(s):  
Shuo Zhang ◽  
Charles J. Hailey ◽  
Kaya Mori ◽  
Maïca Clavel ◽  
Régis Terrier ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Galactic Center ◽  
Spectral Studies ◽  
X Ray ◽  
Sgr A

scholarly journals FADING HARD X-RAY EMISSION FROM THE GALACTIC CENTER MOLECULAR CLOUD Sgr B2

2010 ◽  
Vol 719 (1) ◽  
pp. 143-150 ◽  
Author(s):  
R. Terrier ◽  
G. Ponti ◽  
G. Bélanger ◽  
A. Decourchelle ◽  
V. Tatischeff ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Galactic Center ◽  
X Ray

scholarly journals The Origin of Diffuse X‐Ray and γ‐Ray Emission from the Galactic Center Region: Cosmic‐Ray Particles

2007 ◽  
Vol 656 (2) ◽  
pp. 847-869 ◽  
Author(s):  
F. Yusef‐Zadeh ◽  
M. Muno ◽  
M. Wardle ◽  
D. C. Lis
Keyword(s):  
Galactic Center ◽  
Cosmic Ray ◽  
X Ray ◽  
Center Region ◽  
Γ Ray

Low Energy Galactic Center Gamma Rays from Low Mass X-Ray Binaries

1989 ◽  
pp. 627-632
Author(s):  
W. Kluźniak ◽  
M. Ruderman ◽  
J. Shaham ◽  
M. Tavani
Keyword(s):  
Gamma Rays ◽  
Galactic Center ◽  
Low Energy ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries
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