scholarly journals EBIT charge-exchange measurements and astrophysical applications

2008 ◽  
Vol 86 (1) ◽  
pp. 151-169 ◽  
Author(s):  
B J Wargelin ◽  
P Beiersdorfer ◽  
G V Brown
Keyword(s):  
Charge Exchange ◽  
Supernova Remnants ◽  
Galactic Center ◽  
Line Emission ◽  
Laboratory Measurements ◽  
X Ray ◽  
The Past ◽  
Theoretical Predictions ◽  
X Ray Background ◽  
Key Aspects

The past decade has seen a surge of interest in astrophysical charge exchange (CX). The impetus was the discovery of X-ray emission from comets in 1996, soon followed by the observation of CX emission in planetary atmospheres and throughout the heliosphere. Geocoronal and heliospheric CX are now recognized as contributing a considerable fraction of the soft X-ray background, and stellar-wind charge exchange is expected to occur in the astrospheres surrounding many stars. CX may also contribute to X-ray line emission in supernova remnants, the Galactic Center, and the Galactic Ridge. This article summarizes the key aspects of CX X-ray emission and its astrophysical relevance, and reviews related laboratory measurements and theoretical predictions with particular attention to spectroscopy experiments conducted on electron beam ion traps.PACS Nos.: 32.30.Rj, 34.70.+e, 39.10.+j, 95.30.Dr

scholarly journals Heating of the Interstellar Medium by Supernova Remnants

1983 ◽  
Vol 101 ◽  
pp. 385-392
Author(s):  
Donald P. Cox
Keyword(s):  
Interstellar Medium ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Low Density ◽  
The Sun ◽  
X Ray ◽  
Interstellar Material ◽  
X Ray Background

We observe the heating of interstellar material in young supernova remnants (SNR). In addition, when analyzing the soft X-ray background we find evidence for large isolated regions of apparently hot, low density material. These, we infer, may have been heated by supernovae. One such region seems to surround the Sun. This has been modeled as a supernova remnant viewed from within. The most reasonable parameters are ambient density no ~ 0.004 cm−3, radius of about 100 pc, age just over 105 years (Cox and Anderson 1982).

Line Emission in the X-Ray Background

1971 ◽  
Vol 166 ◽  
pp. L9 ◽  
Author(s):  
Seth Shulman ◽  
Gilbert Fritz ◽  
John F. Meekins ◽  
T. A. Chubb ◽  
H. Friedman ◽  
...  
Keyword(s):  
Line Emission ◽  
X Ray ◽  
X Ray Background

scholarly journals A Limit on Line Emission in the X-Ray Background at High Galactic Latitudes

1971 ◽  
Vol 167 ◽  
pp. L1 ◽  
Author(s):  
E. A. Boldt ◽  
U. D. Desai ◽  
S. S. Holt ◽  
P. J. Serlemitsos
Keyword(s):  
Line Emission ◽  
X Ray ◽  
On Line ◽  
X Ray Background

scholarly journals High-Resolution X-Ray Spectroscopy of Galactic Supernova Remnants

2014 ◽  
Vol 1 (1) ◽  
pp. 200-204
Author(s):  
Satoru Katsuda ◽  
Hiroshi Tsunemi
Keyword(s):  
High Resolution ◽  
Supernova Remnants ◽  
Line Emission ◽  
Collisionless Shock ◽  
Reverse Shock ◽  
X Ray ◽  
Upper Limit ◽  
Hot Plasma ◽  
Forward Shock ◽  
Intensity Ratios

High-resolution X-ray spectroscopy of Galactic supernova remnants (SNRs), based on grating spectrometers onboard XMM-Newton and Chandra, has been revealing a variety of new astrophysical phenomena. Broadened oxygen lines for a northwestern compact knot in SN 1006 clearly show a high oxygen temperature of ~300 keV. The high temperature together with a lower electron temperature (<em>kT<sub>e</sub></em> ~ 1 keV) can be reasonably interpreted as temperature non-equilibration between electrons and oxygen behind a collisionless shock. An ejecta knot in the Puppis A SNR shows blueshifted line emission by ~ 1500kms<sup>-1</sup>. The line widths are fairly narrow in contrast to the SN 1006's knot; an upper limit of 0.9 eV is obtained for O VIII Lyα, which translates to an oxygen temperature of <em>kT<sub>O</sub></em> &lt; 30 keV. The low temperature suggests that the knot was heated by a reverse shock whose velocity is 4 times slower than that of a forward shock. Anomalous intensity ratios in O VII Heα lines, i.e., a stronger forbidden line than a resonance line, is found in a cloud-shock interaction region in Puppis A. The line ratio can be best explained by the charge-exchange emission that should arise at interfaces between the cold/warm clouds and the hot plasma. There are several other targets for which we plan to analyze high-quality grating data prior to the operation of the soft X-ray spectrometer onboard Astro-H.

scholarly journals HEAO-1 Diffuse Soft X-Ray Sky Maps

1984 ◽  
Vol 81 ◽  
pp. 219-221
Author(s):  
John A. Nousek ◽  
Gordon P. Garmire ◽  
George Weaver
Keyword(s):  
Galactic Center ◽  
Energy Interval ◽  
Background Intensity ◽  
X Ray ◽  
The North ◽  
Center Region ◽  
Local Emission ◽  
North Polar ◽  
X Ray Background

Maps of the diffuse soft X-ray background intensity are presented, spanning four energy intervals. The lowest energy interval (0.18-0.56 keV) is dominated by local emission, while the next two intervals (0.56-1.0 keV and 1.0-1.4 keV) reveal more distant and more sharply defined structures. Enlarged maps of several of these structures are presented, including the North Polar Spur, the Galactic Center region and the Eridanus Loop.

scholarly journals Molecular gas in the immediate vicinity of Sgr A* seen with ALMA

2016 ◽  
Vol 11 (S322) ◽  
pp. 129-132
Author(s):  
Lydia Moser ◽  
Álvaro Sánchez-Monge ◽  
Andreas Eckart ◽  
Miguel A. Requena-Torres ◽  
Macarena García-Marin ◽  
...  
Keyword(s):  
Galactic Center ◽  
Line Emission ◽  
Molecular Gas ◽  
Future Studies ◽  
X Ray ◽  
Circumnuclear Disk ◽  
Sgr A ◽  
Central Parsec ◽  
Cloud Cores ◽  
Cold Core

AbstractWe report serendipitous detections of line emission with ALMA in band 3, 6, and 7 in the central parsec of the Galactic center at an up to now highest resolution (<0.7″). Among the highlights are the very first and highly resolved images of sub-mm molecular emission of CS, H13CO+, HC3N, SiO, SO, C2H, and CH3OH in the immediate vicinity (~1″ in projection) of Sgr A* and in the circumnuclear disk (CND). The central association (CA) of molecular clouds shows three times higher CS/X (X: any other observed molecule) luminosity ratios than the CND suggesting a combination of higher excitation - by a temperature gradient and/or IR-pumping - and abundance enhancement due to UV- and/or X-ray emission. We conclude that the CA is closer to the center than the CND is and could be an infalling clump consisting of denser cloud cores embedded in diffuse gas. Moreover, we identified further regions in and outside the CND that are ideally suited for future studies in the scope of hot/cold core and extreme PDR/XDR chemistry and consequent star formation in the central few parsecs.

scholarly journals An X-ray view of Sagittarius C

2016 ◽  
Vol 11 (S322) ◽  
pp. 208-209 ◽  
Author(s):  
D. Chuard ◽  
R. Terrier ◽  
A. Goldwurm ◽  
M. Clavel ◽  
S. Soldi ◽  
...  
Keyword(s):  
Molecular Complex ◽  
Line Emission ◽  
Iron Line ◽  
X Ray ◽  
The Past ◽  
Over Time

AbstractOver the past 15 years, the molecular complex Sgr C has been repeatedly observed with both XMM-Newton and Chandra. These observations reveal new features indicating that the region might be more complex than previously thought. We find that its strong iron line emission at 6.4 keV varies significantly over time, which supports the X-ray reflection scenario.

scholarly journals LABORATORY MEASUREMENTS COMPELLINGLY SUPPORT A CHARGE-EXCHANGE MECHANISM FOR THE “DARK MATTER” ∼3.5 keV X-Ray LINE

2016 ◽  
Vol 833 (1) ◽  
pp. 52 ◽  
Author(s):  
Chintan Shah ◽  
Stepan Dobrodey ◽  
Sven Bernitt ◽  
René Steinbrügge ◽  
José R. Crespo López-Urrutia ◽  
...  
Keyword(s):  
Dark Matter ◽  
Charge Exchange ◽  
Exchange Mechanism ◽  
Laboratory Measurements ◽  
X Ray ◽  
A Charge

scholarly journals New transient Galactic bulge intermediate polar candidate XMMU J175035.2-293557

2018 ◽  
Vol 615 ◽  
pp. L7 ◽  
Author(s):  
F. Hofmann ◽  
G. Ponti ◽  
F. Haberl ◽  
M. Clavel
Keyword(s):  
Galactic Center ◽  
Cataclysmic Variables ◽  
Galactic Bulge ◽  
Optical Counterpart ◽  
X Ray ◽  
The Past ◽  
System A ◽  
Variable Factor ◽  
Intermediate Polars ◽  
X Ray Absorption

Context. For the past decades, a rare subclass of cataclysmic variables (CV), with magnetised white dwarfs (WD) as accretors, has been studied. They are called intermediate polars (IP) and have been suggested to be the main contributors to the diffuse, hard X-ray emission close to the Galactic center (GC) and in the Galactic bulge (GB), because most of them are unresolved there. Aims. In an ongoing X-ray survey (0.5–10 keV energy band) of 3° × 3° around the GC with the XMM-Newton observatory, we conducted a systematic search for transient X-ray sources. Methods. Promising systems were analyzed for spectral, timing, and multiwavelength properties to constrain their nature. Results. We discovered a new highly variable (factor ≳20) X-ray source about 1.25° south of the GC. We found evidence that makes the newly discovered system a candidate IP. The X-ray light curve shows a period of 511 ± 10 s, which can be interpreted as the spin period of the WD. The X-ray spectrum is well fit by a bremsstrahlung model with a temperature of 13.9 ± 2.5 keV, suggesting a WD mass of 0.4−0.5 M⊙. We were unable to identify a blue optical counterpart in any of the candidate sources, as would be expected for IPs. Conclusions. The high X-ray absorption and absence of a clear optical counterpart suggest that the source is most likely located in the GB. This would make the system a transient IP (GK Per class) with an especially high peak X-ray luminosity, which means that it is a very faint X-ray transient.

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