The relation of electron temperature to emission measure and limits of increase in emission measure in soft X-ray flares

1984 ◽  
Vol 286 ◽  
pp. 359 ◽  
Author(s):  
R. E. Denton ◽  
U. Feldman
Keyword(s):  
Electron Temperature ◽  
Emission Measure ◽  
X Ray

Electron Temperature, Emission Measure, and X-Ray Flux in A2 to X2 X-Ray Class Solar Flares

1996 ◽  
Vol 460 ◽  
pp. 1034 ◽  
Author(s):  
U. Feldman ◽  
G. A. Doschek ◽  
W. E. Behring ◽  
K. J. H. Phillips
Keyword(s):  
Electron Temperature ◽  
Solar Flares ◽  
Emission Measure ◽  
X Ray

Electron temperature and emission measure variations during solar X-ray flares

Solar Physics ◽  
1971 ◽  
Vol 21 (1) ◽  
pp. 188-197 ◽  
Author(s):  
D. M. Horan
Keyword(s):  
Electron Temperature ◽  
Emission Measure ◽  
X Ray

scholarly journals Measuring turbulence and gas motions in galaxy clusters via synthetic Athena X-IFU observations

2018 ◽  
Vol 618 ◽  
pp. A39 ◽  
Author(s):  
M. Roncarelli ◽  
M. Gaspari ◽  
S. Ettori ◽  
V. Biffi ◽  
F. Brighenti ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Velocity Dispersion ◽  
Emission Measure ◽  
Systematic Errors ◽  
X Ray ◽  
Fitting Method ◽  
Metal Abundance ◽  
Centroid Shift ◽  
Hydrodynamical Simulations ◽  
Field Unit

Context. The X-ray Integral Field Unit (X-IFU) that will be on board the Athena telescope will provide an unprecedented view of the intracluster medium (ICM) kinematics through the observation of gas velocity, ν, and velocity dispersion, w, via centroid-shift and broadening of emission lines, respectively. Aims. The improvement of data quality and quantity requires an assessment of the systematics associated with this new data analysis, namely biases, statistical and systematic errors, and possible correlations between the different measured quantities. Methods. We have developed an end-to-end X-IFU simulator that mimics a full X-ray spectral fitting analysis on a set of mock event lists, obtained using SIXTE. We have applied it to three hydrodynamical simulations of a Coma-like cluster that include the injection of turbulence. This allowed us to assess the ability of X-IFU to map five physical quantities in the cluster core: emission measure, temperature, metal abundance, velocity, and velocity dispersion. Finally, starting from our measurements maps, we computed the 2D structure function (SF) of emission measure fluctuations, ν and w, and compared them with those derived directly from the simulations. Results. All quantities match with the input projected values without bias; the systematic errors were below 5%, except for velocity dispersion whose error reaches about 15%. Moreover, all measurements prove to be statistically independent, indicating the robustness of the fitting method. Most importantly, we recover the slope of the SFs in the inertial regime with excellent accuracy, but we observe a systematic excess in the normalization of both SFν and SFw ascribed to the simplistic assumption of uniform and (bi-)Gaussian measurement errors. Conclusions. Our work highlights the excellent capabilities of Athena X-IFU in probing the thermodynamic and kinematic properties of the ICM. This will allow us to access the physics of its turbulent motions with unprecedented precision.

scholarly journals Two-temperature magnetohydrodynamic simulations for sub-relativistic active galactic nucleus jets: dependence on the fraction of the electron heating

2020 ◽  
Vol 493 (4) ◽  
pp. 5761-5772 ◽  
Author(s):  
Takumi Ohmura ◽  
Mami Machida ◽  
Kenji Nakamura ◽  
Yuki Kudoh ◽  
Ryoji Matsumoto
Keyword(s):  
Electron Temperature ◽  
X Rays ◽  
Ion Temperature ◽  
Temperature Plasma ◽  
Electron Heating ◽  
Coulomb Collisions ◽  
X Ray ◽  
Jet Plasma ◽  
Magnetohydrodynamic Simulations ◽  
Two Temperature

ABSTRACT We present the results of two-temperature magnetohydrodynamic simulations of the propagation of sub-relativistic jets of active galactic nuclei. The dependence of the electron and ion temperature distributions on the fraction of electron heating, fe, at the shock front is studied for fe = 0, 0.05, and 0.2. Numerical results indicate that in sub-relativistic, rarefied jets, the jet plasma crossing the terminal shock forms a hot, two-temperature plasma in which the ion temperature is higher than the electron temperature. The two-temperature plasma expands and forms a backflow referred to as a cocoon, in which the ion temperature remains higher than the electron temperature for longer than 100 Myr. Electrons in the cocoon are continuously heated by ions through Coulomb collisions, and the electron temperature thus remains at Te > 109 K in the cocoon. X-ray emissions from the cocoon are weak because the electron number density is low. Meanwhile, X-rays are emitted from the shocked intracluster medium (ICM) surrounding the cocoon. Mixing of the jet plasma and the shocked ICM through the Kelvin–Helmholtz instability at the interface enhances X-ray emissions around the contact discontinuity between the cocoon and shocked ICM.

Soft X-ray PHA Diagnostic for the Electron Temperature Measurements on EAST

2009 ◽  
Vol 11 (4) ◽  
pp. 468-471 ◽  
Author(s):  
Xu Ping ◽  
Lin Shiyao ◽  
Hu Liqun ◽  
Duan Yanmin ◽  
Zhang Jizong
Keyword(s):  
Electron Temperature ◽  
Temperature Measurements ◽  
X Ray

scholarly journals Flare of 1970 March 01: A Review and Further Evidence for Adiabatic Heating

1980 ◽  
Vol 86 ◽  
pp. 177-181
Author(s):  
C. Mätzler ◽  
H.J. Wiehl
Keyword(s):  
Thermal Plasma ◽  
Emission Measure ◽  
Impulsive Phase ◽  
Maximum Temperature ◽  
Adiabatic Process ◽  
Projected Area ◽  
X Ray ◽  
Time Profiles ◽  
Average Electron Density ◽  
Average Electron

SummaryThe microwave and hard-X-ray burst of 1970 March 01, 11:27 UT was found to originate from a common thermal plasma with a maximum temperature of 57 keV. The low coronal plasma with an average electron density of about 3.108cm−3 covered a projected area of 5.1018 cm2. In Fig. 1 the time profiles of the emission measure and the temperature are compared with the 10.5 GHz flux while Fig. 2 shows the reversible relationship between the hard X-ray emission measure and temperature during the impulsive phase. The arrows indicate the direction of increasing time. The dashed-dotted line, representing an adiabatic process with an index χ = 5/3, agrees well with the observations showing a compression followed by an expansion (Mätzler et al. 1978).

scholarly journals X-ray Variability of the Flare Star CC Eri

1995 ◽  
Vol 151 ◽  
pp. 170-170
Author(s):  
H.C. Pan ◽  
C. Jordan
Keyword(s):  
Binary Star ◽  
Emission Measure ◽  
Quality Data ◽  
Spectral Variability ◽  
High Quality ◽  
High Quality Data ◽  
X Ray ◽  
Spectroscopic Binary ◽  
Two Temperature ◽  
Continuous Temperature

The flare/spotted spectroscopic binary star CC Eri (HD 16157) was observed in the periods 1990 July 9-11 and 1992 January 26-27 with the ROSAT PSPC detector (Pan and Jordan 1995). These high quality data give the first information on the temporal and spectral variability of CC Eri in the X-ray energy band.During the ROSAT observations the X-ray intensity of the source is variable on timescales from a few minutes to several hours. The X-ray luminosity is in the range 2.5 – 6.8 × 1029 erg s−1, which is similar to values found from previous measurements with the Einstein IPC and EXOSAT LE. On 1990 July 10 an X-ray flare-like event was detected with an exponential rise time of about one hour and a decay time of about two hours. The X-ray spectrum of CC Eri can be described by current thermal plasma codes with two temperature components or with a continuous temperature distribution. The spectral results show that plasma at Te ∼ 107 K exists in the corona of CC Eri. We find that the X-ray spectrum is also variable and the variations of the emission measure, and to a lesser extent of the temperature, are correlated with the source intensity.

The Electron Temperature and Fine Structure of Soft X‐Ray Solar Flares

1999 ◽  
Vol 527 (1) ◽  
pp. 426-434 ◽  
Author(s):  
G. A. Doschek
Keyword(s):  
Fine Structure ◽  
Electron Temperature ◽  
Solar Flares ◽  
X Ray

scholarly journals The Temperature Structure of NGC 7027

1989 ◽  
Vol 131 ◽  
pp. 176-176
Author(s):  
C. T. Daub ◽  
J. P. Basart
Keyword(s):  
Temperature Distribution ◽  
Electron Temperature ◽  
Angular Resolution ◽  
Hot Spot ◽  
Emission Measure ◽  
The Other ◽  
Radio Continuum ◽  
Line Of Sight ◽  
Temperature Structure ◽  
Ngc 7027

Radio maps of the free-free radio continuum flux (angular resolution ≅ 1.3 arcseconds) from NGC 7027 were made with the VLA operating at 20-cm, 6-cm, and 2-cm wavelengths which are near and straddle unit optical depth. Mean line-of-sight electron temperature and emission measure distributions were calculated by pairing the 2-cm and 6-cm maps, and the electron temperature distribution on the near side of the nebula was then obtained from the 20-cm map. The results suggest that the energy balance is complex in this planetary. For example, mean line-of-sight temperatures are higher than average in the direction of one of the bright lobes but not in the direction of the other. Especially noteworthy is an apparent “hot spot” on the near side of the nebula which has no apparent relation to either of the bright lobes, but it is approximately coincident with the brightest portion of the optical image.

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