scholarly journals Spatial Distribution of the Galactic Center Diffuse X-Rays and the Spectra of the Brightest 6.4 keV Clumps

2009 ◽  
Vol 61 (sp1) ◽  
pp. S255-S262 ◽  
Author(s):  
Katsuji Koyama ◽  
Yojiro Takikawa ◽  
Yoshiaki Hyodo ◽  
Tatsuya Inui ◽  
Masayoshi Nobukawa ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Galactic Center ◽  
X Rays

The 6.4 keV Fe Line and the SiO Emission in the GC

2001 ◽  
Vol 205 ◽  
pp. 36-37
Author(s):  
J. Martín-Pintado ◽  
P. de Vicente ◽  
N. Rodríguez-Fernández ◽  
A. Fuente ◽  
P. Planesas
Keyword(s):  
Spatial Distribution ◽  
Gas Phase ◽  
Molecular Clouds ◽  
Galactic Center ◽  
X Rays ◽  
Refractory Elements

We present a map of the Galactic center in the J=l-0 line of SiO covering the region mapped with the ASCA satellite in the 6.4 keV Fe line. We find a correlation between the spatial distribution of the Fe 6.4 keV line and the SiO emission. The SiO abundance increases by more than a factor of 20 in the regions with strong Fe 6.4 keV line. This indicates that the Fe 6.4 keV line mainly arises from molecular clouds with large gas phase abundance of refractory elements. We discuss the implications of the correlation on the origin of the hard X-rays, and the heating and the chemistry of the molecular clouds in the GC.

scholarly journals Particle Propagation in the Galactic Center and Spatial Distribution of Non-Thermal X-Rays

2009 ◽  
Vol 61 (5) ◽  
pp. 1093-1098 ◽  
Author(s):  
Vladimir A. Dogiel ◽  
Dmitrii Chernyshov ◽  
Takayuki Yuasa ◽  
Kwong-Sang Cheng ◽  
Aya Bamba ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Galactic Center ◽  
X Rays ◽  
Particle Propagation

scholarly journals LIGHT SUPERCONDUCTING STRINGS IN THE GALAXY

2007 ◽  
Vol 16 (12b) ◽  
pp. 2399-2405 ◽  
Author(s):  
FRANCESC FERRER ◽  
TANMAY VACHASPATI
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Particle Physics ◽  
Milky Way ◽  
Gamma Ray ◽  
Galactic Center ◽  
Line Emission ◽  
Galactic Magnetic Field ◽  
The Galaxy ◽  
Intense Source

Observations of the Milky Way by the SPI/INTEGRAL satellite have confirmed the presence of a strong 511 keV gamma ray line emission from the bulge, which requires an intense source of positrons in the galactic center. These observations are hard to account for by conventional astrophysical scenarios, whereas other proposals, such as light DM, face stringent constraints from the diffuse gamma ray background. Here we suggest that light superconducting strings could be the source of the observed 511 keV emission. The associated particle physics, at the ~ 1 TeV scale, is within the reach of planned accelerator experiments, while the distinguishing spatial distribution, proportional to the galactic magnetic field, could be mapped by SPI or by future, more sensitive satellite missions.

On the Spatial Distribution of Hard X‐Rays from Solar Flare Loops

1999 ◽  
Vol 527 (2) ◽  
pp. 945-957 ◽  
Author(s):  
Vahe Petrosian ◽  
Timothy Q. Donaghy
Keyword(s):  
Spatial Distribution ◽  
Solar Flare ◽  
X Rays ◽  
Flare Loops

scholarly journals Dust absorption and scattering in the silicon K-edge

2019 ◽  
Vol 627 ◽  
pp. A16 ◽  
Author(s):  
S. T. Zeegers ◽  
E. Costantini ◽  
D. Rogantini ◽  
C. P. de Vries ◽  
H. Mutschke ◽  
...  
Keyword(s):  
Interstellar Dust ◽  
Galactic Center ◽  
Interstellar Extinction ◽  
Line Of Sight ◽  
X Rays ◽  
Laboratory Measurements ◽  
Galactocentric Distance ◽  
Synchrotron Facility ◽  
The Galaxy ◽  
Low Mass

Context. The composition and properties of interstellar silicate dust are not well understood. In X-rays, interstellar dust can be studied in detail by making use of the fine structure features in the Si K-edge. The features in the Si K-edge offer a range of possibilities to study silicon-bearing dust, such as investigating the crystallinity, abundance, and the chemical composition along a given line of sight. Aims. We present newly acquired laboratory measurements of the silicon K-edge of several silicate-compounds that complement our measurements from our earlier pilot study. The resulting dust extinction profiles serve as templates for the interstellar extinction that we observe. The extinction profiles were used to model the interstellar dust in the dense environments of the Galaxy. Methods. The laboratory measurements, taken at the Soleil synchrotron facility in Paris, were adapted for astrophysical data analysis and implemented in the SPEX spectral fitting program. The models were used to fit the spectra of nine low-mass X-ray binaries located in the Galactic center neighborhood in order to determine the dust properties along those lines of sight. Results. Most lines of sight can be fit well by amorphous olivine. We also established upper limits on the amount of crystalline material that the modeling allows. We obtained values of the total silicon abundance, silicon dust abundance, and depletion along each of the sightlines. We find a possible gradient of 0.06 ± 0.02 dex/kpc for the total silicon abundance versus the Galactocentric distance. We do not find a relation between the depletion and the extinction along the line of sight.

Dust-grain scattering of X-rays observed during the lunar occultation of a transient X-ray source near the Galactic center

1990 ◽  
Vol 353 ◽  
pp. 480 ◽  
Author(s):  
Kazuhisa Mitsuda ◽  
Toshiaki Takeshima ◽  
Tsuneo Kii ◽  
Nobuyuki Kawai
Keyword(s):  
Galactic Center ◽  
X Rays ◽  
X Ray ◽  
Lunar Occultation ◽  
Grain Scattering ◽  
Dust Grain

scholarly journals Bulge Globular Clusters

2002 ◽  
Vol 207 ◽  
pp. 15-23
Author(s):  
B. Barbuy ◽  
S. Ortolani ◽  
E. Bica
Keyword(s):  
Spatial Distribution ◽  
Globular Clusters ◽  
Galactic Center ◽  
Bulge Formation

The properties of the globular clusters located within 20° × 20° of the Galactic Center are discussed. In particular their spatial distribution, metallicities and ages are presented and discussed in the context of different scenarios of bulge formation.

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