scholarly journals On the Origin of the 6.4 keV line from the GRXE

2011 ◽  
Vol 7 (S279) ◽  
pp. 329-330
Author(s):  
Romanus Eze ◽  
Kei Saitou ◽  
Ken Ebisawa
Keyword(s):  
Galactic Plane ◽  
Cataclysmic Variables ◽  
Line Emission ◽  
Emission Lines ◽  
Symbiotic Stars ◽  
Line Flux ◽  
X Ray ◽  
Fluorescence Line ◽  
Magnetic Cataclysmic Variables ◽  
Cold Matter

AbstractThe Galactic Ridge X-ray Emission (GRXE) spectrum has strong iron emission lines at 6.4, 6.7, and 7.0 keV, each corresponding to the neutral (or low-ionized), He-like, and H-like iron ions. The 6.4 keV fluorescence line is due to irradiation of neutral (or low ionized) material (iron) by hard X-ray sources, indicating uniform presence of the cold matter in the Galactic plane. In order to resolve origin of the cold fluorescent matter, we examined the contribution of the 6.4 keV line emission from white dwarf surfaces in the hard X-ray emitting symbiotic stars (hSSs) and magnetic cataclysmic variables (mCVs) to the GRXE. In our spectral analysis of 4 hSSs and 19 mCVs observed with Suzaku, we were able to resolve the three iron emission lines. We found that the equivalent-widths (EWs) of the 6.4 keV lines of hSSs are systematically higher than those of mCVs, such that the average EWs of hSSs and mCVs are 180−10+50 eV and 93−3+20 eV, respectively. The EW of hSSs compares favorably with the typical EWs of the 6.4 keV line in the GRXE of 90–300 eV depending on Galactic positions. Average 6.4 keV line luminosities of the hSSs and mCVs are 9.2 × 1039 and 1.6 × 1039 photons s−1, respectively, indicating that hSSs are intrinsically more efficient 6.4 keV line emitters than mCVs. We estimated required space densities of hSSs and mCVs to account for all the GRXE 6.4 keV line emission flux to be 2 × 10−7 pc−3 and 1 × 10−6 pc−3, respectively. We also estimated the actual 6.4 keV line contribution from the hSSs, which is as much as 30% of the observed GRXE flux, and that from the mCV is about 50%. We therefore conclude that the GRXE 6.4 keV line flux is primarily explained by hSSs and mCVs.

scholarly journals Suzaku View of Magnetic Cataclysmic Variables

2015 ◽  
Vol 2 (1) ◽  
pp. 99-102
Author(s):  
T. Yuasa
Keyword(s):  
Cataclysmic Variables ◽  
Emission Lines ◽  
Spectral Model ◽  
Cataclysmic Variable ◽  
X Ray ◽  
Intermediate Polars ◽  
Magnetic Cataclysmic Variables

Results of magnetic cataclysmic variable studies performed with the Suzaku satellite are reviewed in this article. Particular emphasis is placed on the recent update of X-ray spectral model of intermediate polars, possible kinematically redshifted fluorescent Fe K emission lines, and the magnetic CV contribution to the Galactic ridge X-ray emission.

scholarly journals Extreme Ultraviolet Spectroscopy of Magnetic Cataclysmic Variables

1996 ◽  
Vol 152 ◽  
pp. 309-316
Author(s):  
Frits Paerels ◽  
Min Young Hur ◽  
Christopher W. Mauche
Keyword(s):  
High Resolution ◽  
White Dwarf ◽  
Extreme Ultraviolet ◽  
Cataclysmic Variables ◽  
Ultraviolet Spectroscopy ◽  
Temperature Structure ◽  
Polar Cap ◽  
Ultraviolet Emission ◽  
X Ray ◽  
Magnetic Cataclysmic Variables

A longstanding problem in the interpretation of the X-ray and extreme ultraviolet emission from strongly magnetic cataclysmic variables can be addressed definitively with high resolution EUV spectroscopy. A detailed photospheric spectrum of the accretion-heated polar cap of the white dwarf is sensitive in principle to the temperature structure of the atmosphere. This may allow us to determine where and how the bulk of the accretion energy is thermalized. The EUVE data on AM Herculis and EF Eridani are presented and discussed in this context.

X-ray emission from non-magnetic cataclysmic variables

Nature ◽  
1984 ◽  
Vol 308 (5959) ◽  
pp. 519-521 ◽  
Author(s):  
A. R. King ◽  
G. Shaviv
Keyword(s):  
Cataclysmic Variables ◽  
X Ray ◽  
Magnetic Cataclysmic Variables

scholarly journals X-Ray Emission from Non-Magnetic Cataclysmic Variables

1987 ◽  
Vol 93 ◽  
pp. 225-233
Author(s):  
H. Van Der Woerd
Keyword(s):  
Boundary Layer ◽  
Spectral Characteristics ◽  
Cataclysmic Variables ◽  
Large Sample ◽  
X Ray ◽  
Magnetic Cataclysmic Variables

AbstractEXOSAT observations of a large sample of non-magnetic cataclysmic variables have led to the detection of VW Hyi and OY Car as strong soft X-ray sources during superoutburst. The spectral characteristics of the X-ray emission of these SU Uma systems are compared. It is proposed that both systems have, besides a cool, optically thick boundary layer, an extended hot, optically thin corona.

scholarly journals A stellar census in globular clusters with MUSE: A spectral catalogue of emission-line sources

2019 ◽  
Vol 631 ◽  
pp. A118 ◽  
Author(s):  
Fabian Göttgens ◽  
Tim-Oliver Husser ◽  
Sebastian Kamann ◽  
Stefan Dreizler ◽  
Benjamin Giesers ◽  
...  
Keyword(s):  
Emission Line ◽  
Binary Stars ◽  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Variable Stars ◽  
Emission Lines ◽  
Data Set ◽  
Stellar Spectra ◽  
X Ray ◽  
Emission Line Galaxies

Aims. Globular clusters produce many exotic stars due to a much higher frequency of dynamical interactions in their dense stellar environments. Some of these objects were observed together with several hundred thousand other stars in our MUSE survey of 26 Galactic globular clusters. Assuming that at least a few exotic stars have exotic spectra (i.e. spectra that contain emission lines), we can use this large spectroscopic data set of over a million stellar spectra as a blind survey to detect stellar exotica in globular clusters. Methods. To detect emission lines in each spectrum, we modelled the expected shape of an emission line as a Gaussian curve. This template was used for matched filtering on the differences between each observed 1D spectrum and its fitted spectral model. The spectra with the most significant detections of Hα emission are checked visually and cross-matched with published catalogues. Results. We find 156 stars with Hα emission, including several known cataclysmic variables (CV) and two new CVs, pulsating variable stars, eclipsing binary stars, the optical counterpart of a known black hole, several probable sub-subgiants and red stragglers, and 21 background emission-line galaxies. We find possible optical counterparts to 39 X-ray sources, as we detected Hα emission in several spectra of stars that are close to known positions of Chandra X-ray sources. This spectral catalogue can be used to supplement existing or future X-ray or radio observations with spectra of potential optical counterparts to classify the sources.

scholarly journals The Soft X-ray Background Spectrum from DXS

1997 ◽  
Vol 166 ◽  
pp. 83-90 ◽  
Author(s):  
W.T. Sanders ◽  
R.J. Edgar ◽  
D.A. Liedahl ◽  
J.P. Morgenthaler
Keyword(s):  
Galactic Plane ◽  
Emission Lines ◽  
Background Spectrum ◽  
Local Bubble ◽  
X Ray ◽  
Hot Plasma ◽  
Solar Abundances ◽  
Ionic Emission ◽  
X Ray Background ◽  
Ionization Balance

AbstractThe Diffuse X-ray Spectrometer (DXS) obtained spectra of the low energy X-ray (44 – 83 Å) diffuse background near the galactic plane from galactic longitudes 150° ≲ l ≲ 300° with ≲ 3 Å spectral resolution and ~ 15° angular resolution. Thus, DXS measured X-ray spectra that arise almost entirely from within the Local Bubble. The DXS spectra show emission lines and emission-line blends, indicating that the source of the X-ray emission is thermal – hot plasma in the Local Bubble. The measured spectra are not consistent with those predicted by standard coronal models, either with solar abundances or depleted abundances, over the temperature range 105 – 107 K. The measured spectra are also inconsistent with the predictions of various non-equilibrium models. A nearly acceptable fit to DXS spectra can be achieved using a hybrid model that combines the Raymond & Smith ionization balance calculation with recently calculated (by DAL) ionic emission lines.

scholarly journals Hard X-ray properties of magnetic cataclysmic variables

2010 ◽  
Author(s):  
S. Scaringi ◽  
A. J. Bird ◽  
A. J. Norton ◽  
C. Knigge ◽  
A. B. Hill ◽  
...  
Keyword(s):  
Cataclysmic Variables ◽  
X Ray ◽  
Magnetic Cataclysmic Variables
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