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Journal articles on the topic 'X-RAY EMISSION ANALYSIS'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Szász, A., and J. Kojnok. "Soft X-ray Emission Depth Profile Analysis: SXDA." Applied Surface Science 24, no. 1 (1985): 34–56. http://dx.doi.org/10.1016/0169-4332(85)90211-9.

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2

Zane, Silvia. "Magnetar X-ray emission mechanisms." Proceedings of the International Astronomical Union 8, S291 (2012): 160. http://dx.doi.org/10.1017/s1743921312023484.

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AbstractSoft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are peculiar X-ray sources which are believed to be magnetars: ultra-magnetized neutron stars which emission is dominated by surface fields (often in excess of 1E14 G, i.e. well above the QED threshold).Spectral analysis is an important tool in magnetar astrophysics since it can provide key information on the emission mechanisms. The first attempts at modelling the persistent (i.e. outside bursts) soft X-ray (¡10 keV) spectra of AXPs proved that a model consisting of a blackbody (kT 0.3-0.6 keV) plus a power-law (photon index 2-4) could successfully reproduce the observed emission. Moreover, INTEGRAL observations have shown that, while in quiescence, magnetars emit substantial persistent radiation also at higher energies, up to a few hundreds of keV. However, a convincing physical interpretation of the various spectral components is still missing.In this talk I will focus on the interpretation of magnetar spectral properties during quiescence. I will summarise the present status of the art and the currents attempts to model the broadband persistent emission of magnetars (from IR to hard Xrays) within a self consistent, physical scenario.

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3

Furukawa, Y., K. Yokoyama, K. Inoue, K. Ishibashi, and H. Fukuyama. "A compact wavelength-dispersive X-ray spectrometer for particle-induced X-ray emission analysis." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 118, no. 1-4 (1996): 372–76. http://dx.doi.org/10.1016/0168-583x(95)01180-3.

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4

NAKANISHI, Tomoko M., Shoji FUTATSUGAWA, and Kouichiro SERA. "PIXE(Proton Induced X-Ray Emission) Analysis of Caatinger." RADIOISOTOPES 44, no. 2 (1995): 103–7. http://dx.doi.org/10.3769/radioisotopes.44.103.

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5

Natal da Luz, H., D. Spemann, W. Meyer-Klaucke, and W. Tröger. "Analysis of proteins by particle induced X-ray emission." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 231, no. 1-4 (2005): 308–14. http://dx.doi.org/10.1016/j.nimb.2005.01.075.

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6

Wei, Chau-Chin. "TUMOR ANALYSIS BY PARTICLE-INDUCED X-RAY EMISSION (PIXE)." Acta Pharmacologica et Toxicologica 59 (March 13, 2009): 274–76. http://dx.doi.org/10.1111/j.1600-0773.1986.tb02761.x.

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7

Ecker, Klaus H., Hans-Peter Weise, and Karl L. Merkle. "Trace Analysis by Heavy Ion Induced X-Ray Emission." Microchimica Acta 133, no. 1-4 (2000): 313–17. http://dx.doi.org/10.1007/s006040070112.

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8

Hong-Kou, Li, and K. G. Malmqvist. "Hair analysis using proton induced X-ray emission techniques." Science of The Total Environment 42, no. 1-2 (1985): 213–17. http://dx.doi.org/10.1016/0048-9697(85)90024-5.

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9

Weinhardt, Lothar, Dirk Hauschild, Ralph Steininger, et al. "Sulfate Speciation Analysis Using Soft X-ray Emission Spectroscopy." Analytical Chemistry 93, no. 23 (2021): 8300–8308. http://dx.doi.org/10.1021/acs.analchem.1c01187.

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10

Kurt, V. G. "Electrons and X-Ray Emission of Solar Flares." Symposium - International Astronomical Union 142 (1990): 409–13. http://dx.doi.org/10.1017/s007418090008832x.

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A statistical analysis of solar flare X-rays and interplanetary particle fluxes, measured onboard VENERA-13, 14 Spacecraft, was performed. The correlation of fluences for different manifestations of solar flares is strong, especially for fast electrons and hard and soft X-ray emissions. Frequency dependence on fluence value ϵi for practically all Kinds of solar flare emission can be described by power law ν (ϵ > ϵO) ∼ ϵ−0.45±0.15 which does not change significantly with solar activity. For different Hα flare importances the values of ϵi were obtained. It is proposed that appearance of certain energy flare frequency is strongly dependent on some scale factor.

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11

Hall, Gene S., and Eliahu Navon. "Proton-induced X-ray and gamma ray emission analysis of biological samples." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 15, no. 1-6 (1986): 629–31. http://dx.doi.org/10.1016/0168-583x(86)90381-2.

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12

Derfoul, H., E. Leboucher-Dalimier, I. Gharbi, and A. Poquerusse. "Radial inhomogeneity diagnostics deduced from space-resolved X-ray emission." Laser and Particle Beams 12, no. 3 (1994): 485–93. http://dx.doi.org/10.1017/s026303460000834x.

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Radial inhomogeneity diagnostics in hot and dense laser plasmas are presented. By means of an analysis of the spatially resolved X-ray transverse emission of the plasma and of a theoretical modeling, we can access directly to the radial emission coefficient and to the transverse gradients. The intense aluminum Lyβ line has been chosen for this study, and different structured targets have been used to control the radiative transfer in the transverse direction. These targets (large or narrow emissive strips) give complementary results for the emission in the core (i.e., near the laser-target axis) or in the border of the plasma.

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13

McColloug, M. L., and S. L. Mufson. "Analysis of Multiwavelength Observations of IC443." International Astronomical Union Colloquium 101 (1988): 403–6. http://dx.doi.org/10.1017/s025292110010274x.

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AbstractHigh resolution observations at radio, infrared, optical and X-ray wavelengths have been made (Mufson et al. 1986). The infrared spectrum determined from the IRAS observations has been fitted with models which include shock heated dust, infrared line emission, and radiatively heated dust emission. Numerical simulations of a supernova expanding into a uniform medium, which describe the X-ray and large scale radio emission, are presented.

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14

Preibisch, Thomas. "X-ray Emission from Brown Dwarfs." Symposium - International Astronomical Union 219 (2004): 285–95. http://dx.doi.org/10.1017/s0074180900182257.

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During the last few years, X-ray emission has been detected from numerous brown dwarfs. Most of the X-ray detected brown dwarfs are very young objects with ages of at most 107 years, and all are still relatively warm, with late M spectral types. Their typical fractional X-ray luminosities are (LX/Lbol) ∼ 10—4 — 10—3, i.e. very similar to the values observed for active very-low mass stars. Their X-ray lightcurves show low-level variability, but in most cases no large flares; this implies that the young brown dwarfs are able to produce quiescent X-ray emission, not only occasional flares. An analysis of the Chandra X-ray spectra of several brown dwarfs yields surprisingly low plasma temperatures between 3 MK and 10 MK for some of the M8-9 dwarfs and indicates a decline in plasma temperature with decreasing effective temperature (or increasing age). The lack of X-ray detections for dwarfs cooler than spectral type M9 is consistent with the strong drop of activity observed in Hα at spectral types around M9. The observed X-ray emission from the young brown dwarfs with late M spectral type can be understood as a consequence of the fact that these objects are still warm enough to maintain partially ionized atmospheres which are capable of sustaining electrical currents. In the cooler, essentially neutral atmospheres of the older L and T dwarfs such currents are probably shut off, preventing the buildup of magnetic free energy and the support for magnetically heated chromospheres and coronae.

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15

Braziewicz, Janusz, Maciej Karwowski, Marian Jaskóla, and Marek Pajek. "X-Ray Fluorescence Analysis of Ancient Glasses." Advances in X-ray Analysis 39 (1995): 857–60. http://dx.doi.org/10.1154/s0376030800023338.

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Different analytical methods can be applied to the analysis of the chemical composition of archeological artefacts. The methods presently used to examine archeological artefacts include: emission spectrometry, atomic absorption spectroscopy, x-ray fluorescence spectrometry and neutron activation. The use of these techniques is limited by several factors such as: the size of a sample that can be taken from the object, the availability of the method in the sense of easy access, and the cost of and time spent for the analysis.

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16

Yufeng, Yu. "Inversion of the Attenuated X-Ray Transforms: Method of Riesz Potentials." Journal of Function Spaces 2020 (March 23, 2020): 1–7. http://dx.doi.org/10.1155/2020/5896328.

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The attenuated X-ray transform arises from the image reconstruction in single-photon emission computed tomography. The theory of attenuated X-ray transforms is so far incomplete, and many questions remain open. This paper is devoted to the inversion of the attenuated X-ray transforms with nonnegative varying attenuation functions μ, integrable on any straight line of the plane. By constructing the symmetric attenuated X-ray transform Aμ on the plane and using the method of Riesz potentials, we obtain the inversion formula of the attenuated X-ray transforms on Lpℝ21≤p<2 space, with nonnegative attenuation functions μ, integrable on any straight line in ℝ2. These results are succinct and may be used in the type of computerized tomography with attenuation.

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17

Neustroev, V. V., K. L. Page, E. Kuulkers, et al. "Superhumps linked to X-ray emission." Astronomy & Astrophysics 611 (March 2018): A13. http://dx.doi.org/10.1051/0004-6361/201731719.

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Context. We present more than 4 years of Swift X-ray observations of the 2013 superoutburst, subsequent decline and quiescence of the WZ Sge-type dwarf nova SSS J122221.7−311525 (SSS J122222) from 6 days after discovery. Aims. Only a handful of WZ Sge-type dwarf novae have been observed in X-rays, and until recently GW Lib was the only binary of this type with complete coverage of an X-ray light curve throughout a superoutburst. We collected extensive X-ray data of a second such system to understand the extent to which the unexpected properties of GW Lib are common to the WZ Sge class. Methods. We collected 60 Swift-XRT observations of SSS J122222 between 2013 January 6 and 2013 July 1. Four follow-up observations were performed in 2014, 2015, 2016 and 2017. The total exposure time of our observations is 86.6 ks. We analysed the X-ray light curve and compared it with the behaviour of superhumps which were detected in the optical light curve. We also performed spectral analysis of the data. The results were compared with the properties of GW Lib, for which new X-ray observations were also obtained. Results. SSS J122222 was variable and around five times brighter in 0.3–10 keV X-rays during the superoutburst than in quiescence, mainly because of a significant strengthening of a high-energy component of the X-ray spectrum. The post-outburst decline of the X-ray flux lasted at least 500 d. The data show no evidence of the expected optically thick boundary layer in the system during the outburst. SSS J122222 also exhibited a sudden X-ray flux change in the middle of the superoutburst, which occurred exactly at the time of the superhump stage transition. A similar X-ray behaviour was also detected in GW Lib. Conclusions. We show that the X-ray flux exhibits changes at the times of changes in the superhump behaviour of both SSS J122222 and GW Lib. This result demonstrates a relationship between the outer disc and the white dwarf boundary layer for the first time, and suggests that models for accretion discs in high mass ratio accreting binaries are currently incomplete. The very long decline to X-ray quiescence is also in strong contrast to the expectation of low viscosity in the disc after outburst.

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18

MACARTHUR, J. D., and XIN-PEI MA. "A REVIEW OF PARTICLE-INDUCED X-RAY EMISSION IN GEOLOGY." International Journal of PIXE 01, no. 04 (1991): 311–38. http://dx.doi.org/10.1142/s0129083591000226.

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Particle-induced X-ray emission is very well suited for the analysis of geological samples. This review discusses the characteristics for such analyses. For light-element analysis, the complimentary technique of particle-induced gamma ray emission is also discussed since the emission of gamma rays occurs simultaneously with the X-rays. Not only are exploratory investigations of PIXE's capabilities presented but also synopses of studies aimed at answering geological questions. The latter have become more and more common in the last few years, an indication of PIXE's maturity as a technique for clement analysis of geological material.

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19

Vilmer, N. "Solar Hard X-Ray and Gamma-Ray Observations from GRANAT." International Astronomical Union Colloquium 142 (1994): 611–21. http://dx.doi.org/10.1017/s0252921100077885.

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AbstractHard X-rays and gamma-rays are the most direct signature of the energetic electrons and ions which are accelerated during solar flares. Since the beginning of 1990 the PHEBUS instrument and the SIGMA anticoincidence shield aboard GRANAT have provided hard X-ray and gamma-ray observations of solar bursts in the energy range 0.075-124 and 0.200-15 MeV, respectively. After a brief description of the experiments, we present some results obtained on solar bursts recorded in 1990 and 1991 June. Special emphasis is given to the results related with particle acceleration during solar flares.The first part of the review is devoted to the constraints obtained on the electron acceleration timescale through the analysis of the temporal characteristics of the bursts. Combined studies of hard X-ray and gamma-ray emissions from PHEBUS and radio emissions from the Nançay Multifrequency Radioheliograph are used to infer constraints on the coronal magnetic topology involved in flares. The characteristics (location, spectrum) of the radio-emitting sources are found to vary within a flare from one hard X-ray peak to the other. Hard X-ray and gamma-ray burst onsets and rapid increases of the > 10 MeV emission are coincident with changes in the associated radio emission pattern. These results will be discussed in the context of the flare energy release.The second part of the paper concerns the heliocentric angle distribution of > 10 MeV events and presents more detailed observations of some of the largest flares in the gamma-ray line and the high-energy domains produced by ultrarelativistic electrons and > 100 MeV nucleon−1 ions. The PHEBUS observations of the gamma-ray line flare of 11 June 1991 have been used to deduce the hardness of the accelerated ion spectrum. The link between the main part of the flare and the late long-lasting >50 MeV emission detected by EGRET/COMPTON is discussed. Finally some observations of the large 1990 May 24 flare which produced a large neutron event at ground level are presented.Subject headings: acceleration of particles — Sun: flares — Sun: radio radiation — Sun: X-rays, gamma rays

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20

OURA, KENJIRO. "Characterization of surface structure. Particle induced x-ray emission analysis." Nihon Kessho Gakkaishi 29, no. 2 (1987): 145–47. http://dx.doi.org/10.5940/jcrsj.29.145.

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21

Luta, A. M., I. I. Kravchenko, F. E. Dunnam, H. A. Van Rinsvelt, and C. P. Meyer. "Proton induced X-ray emission analysis of aberrant cowrie shells." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 215, no. 1-2 (2004): 223–27. http://dx.doi.org/10.1016/s0168-583x(03)01791-9.

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22

Orlić, N., J. Dobrinić, and P. R. Salvi. "Elemental analysis of archaeological objects by X-ray emission spectroscopy." Radiation Physics and Chemistry 51, no. 4-6 (1998): 717. http://dx.doi.org/10.1016/s0969-806x(97)00246-6.

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23

Wallenwein, R., H. Blank, E. K. Jessberger, and K. Traxel. "Proton Induced X-Ray Emission (Pixe) Analysis of Meteoritic Microsamples." International Astronomical Union Colloquium 85 (1985): 157–58. http://dx.doi.org/10.1017/s0252921100084542.

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AbstractInterplanetary dust particles (IDPs) collected in the stratosphere are thought to be mostly of cometary origin. They survived heating during their deceleration in the earth’s atmosphere (1). Because of their small size (< 50 μm ) and mass (< 10−7 g) they are difficult to analyse. Special preparation and examination methods have been developed for their investigations (2). We set out to study the trace-element-composition of these particles using the Heidelberg proton microprobe.

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24

F. Silva, Tiago, Gustavo F. Trindade, and Marcia A. Rizzutto. "Multivariate analysis applied to particle-induced X-ray emission mapping." X-Ray Spectrometry 47, no. 5 (2018): 372–81. http://dx.doi.org/10.1002/xrs.2953.

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25

Yuasa, Takayuki, Kazuo Makishima, and Kazuhiro Nakazawa. "BROADBAND SPECTRAL ANALYSIS OF THE GALACTIC RIDGE X-RAY EMISSION." Astrophysical Journal 753, no. 2 (2012): 129. http://dx.doi.org/10.1088/0004-637x/753/2/129.

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26

FLOCCHINI, ROBERT G., MANUEL C. LAGUNAS-SOLAR, and BRIAN P. PERLEY. "APPLICATIONS OF X-RAY EMISSION TO ELEMENTAL ANALYSIS OF FOODS." International Journal of PIXE 06, no. 01n02 (1996): 375–94. http://dx.doi.org/10.1142/s0129083596000405.

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Trace element analysis via X-Ray Fluorescence (XRF) and Proton-Induced X-Ray Emission (PIXE) techniques were applied to several samples of fresh and processed foods. Thin samples of fresh fruits and vegetables, processed dry foods. and spices were included in these analyses. The results indicate that XRF and/or PIXE analysis is applicable to these types of samples but require special and simple modifications in sample preparation techniques, and the inclusion of new matrix type corrections for data analysis. However, the non-destructive nature, reproducibility, efficiency and high sensitivity that characterize these multi-element analytical procedures can provide new potential methods for detecting trace elements in foods and in many agricultural commodities. Toxic metals such as Hg, Pb. and As were detected in some foods. In addition, other essential or neutral trace elements such as Na, K, Mg, Ca, Cu, Cr, V, Zn, Mo, Fe, Mn, Ni, Se, Cl, S, and P were also detected. These and other elements can be analyzed rapidly and with high sensitivity for applications in process control and for certification of food quality. Developing these techniques and procedures specifically for food and for various agricultural products may provide new analytical options and help mitigate the expected impact of forthcoming regulations intended to establish limits and tolerance levels for micro toxicants and other essential nutrients in foods and agricultural products.

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27

Panaitescu, A., P. Meszaros, N. Gehrels, D. Burrows, and J. Nousek. "Analysis of the X-ray emission of nine Swift afterglows." Monthly Notices of the Royal Astronomical Society 366, no. 4 (2006): 1357–66. http://dx.doi.org/10.1111/j.1365-2966.2005.09900.x.

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28

Lytle, N. W., M. W. Hill, K. E. Lambert, N. F. Mangelson, and S. S. W. Kwak. "Proton-induced X-ray emission analysis of munitions disposal residues." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 10-11 (May 1985): 650–52. http://dx.doi.org/10.1016/0168-583x(85)90075-8.

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29

Anderson, Alan J., Alan H. Clark, Xin-Pei Ma, Gerald R. Palmer, J. Duncan MacArthur, and Edwin Roedder. "Proton-induced X-ray and gamma-ray emission analysis of unopened fluid inclusions." Economic Geology 84, no. 4 (1989): 924–39. http://dx.doi.org/10.2113/gsecongeo.84.4.924.

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30

MUKOYAMA, TAKESHI. "ANALYSIS OF X-RAY SPECTRA BY GENETIC ALGORITHM." International Journal of PIXE 09, no. 03n04 (1999): 111–23. http://dx.doi.org/10.1142/s0129083599000206.

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The X-ray emission spectra have been analyzed by the genetic algorithm. The X-ray peaks are represented by Gaussians or Lorentzians and the best estimates of their parameters are determined with the optimization strategy based on the mechanism of natural selection and natural genetics. The calculated results for artificial, pseudo-experimental, and experimental spectra are compared with those obtained by other methods and the validity of the present method is demonstrated.

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31

Brissaud, I., P. Chevallier, C. Dardenne, et al. "Analysis of Gaulish coins by proton induced X-ray emission, synchrotron radiation X-ray fluorescence and neutron activation analysis." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 49, no. 1-4 (1990): 305–8. http://dx.doi.org/10.1016/0168-583x(90)90265-v.

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32

Pallavicini, R., L. Stella, and G. Tagliaferri. "X-ray emission from solar neighbourhood flare stars." Symposium - International Astronomical Union 137 (1990): 147–51. http://dx.doi.org/10.1017/s0074180900187625.

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A brief summary is given of a comprehensive analysis of EXOSAT observations of solar neighbourhood flare stars. Special attention is devoted to the discussion of quiescent X-ray emission and time variability.

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33

Panagiotou, C., I. E. Papadakis, E. S. Kammoun, and M. Dovčiak. "Multiwavelength power-spectrum analysis of NGC 5548." Monthly Notices of the Royal Astronomical Society 499, no. 2 (2020): 1998–2006. http://dx.doi.org/10.1093/mnras/staa2920.

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ABSTRACT NGC 5548 was recently monitored intensively from NIR to X-rays as part of the STORM campaign. Its disc emission was found to lag behind the observed X-rays, while the measured time lag was increasing with wavelength. These results are consistent with the assumption that short-term variability in AGN emission is driven by the X-ray illumination of the accretion disc. In this work, we studied the power spectrum of UV/optical and X-ray emission of NGC 5548, using the data of the STORM campaign as well as previous Swift data, in order to investigate the relation between the UV/optical and X-ray variability and to examine its consistency with the above picture. We demonstrate that even the power spectrum results are compatible with a standard disc being illuminated by X-rays, with low accretion rates, but the details are not entirely consistent with the results from the modelling of the ‘τ versus λ’ relation. The differences indicate that the inner disc might be covered by a ‘warm corona’ which does not allow the detection of UV/optical emission from the inner disc. Finally, we found strong evidence that the UV emission of NGC 5548 is not stationary.

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34

White, R., M. Breuhaus, R. Konno, S. Ohm, B. Reville та J. A. Hinton. "Gamma-ray and X-ray constraints on non-thermal processes in η Carinae". Astronomy & Astrophysics 635 (березень 2020): A144. http://dx.doi.org/10.1051/0004-6361/201937031.

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The binary system η Carinae is a unique laboratory that facilitates the study of particle acceleration to high energies under a wide range of conditions, including extremely high densities around periastron. To date, no consensus has emerged as to the origin of the gigaelectronvolt γ-ray emission in this important system. With a re-analysis of the full Fermi-LAT data set for η Carinae, we show that the spectrum is consistent with a pion decay origin. A single population leptonic model connecting X-ray to γ-ray emission can be ruled out. We revisit our physical model from 2015, based on two acceleration zones associated with the termination shocks in the winds of both stars. We conclude that inverse Compton emission from in-situ accelerated electrons dominates the hard X-ray emission detected with NuSTAR at all phases away from periastron and that pion-decay from shock accelerated protons is the source of γ-ray emission. Very close to periastron there is a pronounced dip in hard X-ray emission, concomitant with the repeated disappearance of the thermal X-ray emission, which we interpret as due to the suppression of significant electron acceleration in the system. Within our model, the residual emission seen by NuSTAR at this phase can be accounted for with secondary electrons produced in interactions of accelerated protons, which agrees with the variation in pion-decay γ-ray emission. Future observations with H.E.S.S., CTA, and NuSTAR should confirm or refute this scenario.

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35

Freyberg, M. J., and J. H. M. M. Schmitt. "Modeling the Galactic ¾ keV X-ray Background." International Astronomical Union Colloquium 166 (1997): 309–20. http://dx.doi.org/10.1017/s0252921100071177.

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AbstractWe have analyzed the ROSAT PSPC all-sky survey maps of the soft X-ray background (SXRB) in the ¾ keV band. One approach was to study the large-scale distribution of the X-ray emission with a multipole analysis. Here a significant dipole toward the galactic center region was found. This is interpreted in terms of variation of distant X-ray emission, e.g. galactic halo. Also a smallscale structure analysis of the ¾ keV X-ray sky has been performed and a new analytic fluctuation probability distribution has been derived. No significant excess over the expected extragalactic point source contribution has been found. Finally, X-ray colours have been used to investigate spectral variations of the SXRB.

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36

Wheatley, Peter J. "Soft X-Ray Flickering of AM Her." International Astronomical Union Colloquium 158 (1996): 211–12. http://dx.doi.org/10.1017/s0252921100038653.

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I present preliminary results from an analysis of the flickering in the only off-axis, high-state observation of AM Her with the ROSAT PSPC. At high Ṁ, the ROSAT count rates are dominated by optically-thick emission from the white-dwarf surface, which is heated directly by the accretion flow. This emission is very soft, predominantly below 0.4keV, and exhibits strong flickering.

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37

Guerrero Roncel, Martín A., and You-Hua Chu. "An X-ray survey of Wolf-Rayet stars in the Magellanic Clouds." Symposium - International Astronomical Union 212 (2003): 718–19. http://dx.doi.org/10.1017/s0074180900213193.

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We have used archival Chandra-acis observations to search for X-ray emission from WR stars in the Magellanic Clouds (MCs), where the low interstellar absorption and known distances make it easy to compare X-ray luminosities with spectral types and binary status of WR stars. We have detected X-ray emission from ~20 WR stars in the MCs with X-ray luminosities of 6.6×1032-1.4×1035 ergs s–1. The analysis of the X-ray spectra of the brightest sources indicates that the X-ray emitting gas has temperatures ≥ 1.0×107 K, as expected in colliding winds. We will compare these results with the binary status of the WR stars to determine the amounts of the X-ray emission produced in the colliding winds for WR stars in binary systems and to assess the X-ray emission from single WR stars.

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38

Alfonso-Garzón, J., C. Sánchez-Fernández, P. A. Charles, et al. "Optical/X-ray correlations during the V404 Cygni June 2015 outburst." Astronomy & Astrophysics 620 (December 2018): A110. http://dx.doi.org/10.1051/0004-6361/201834102.

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Context. We present a multiwavelength analysis of the simultaneous optical and X-ray light curves of the microquasar V404 Cyg during the June 2015 outburst. Aims. We have performed a comprehensive analysis of all the INTEGRAL/IBIS, JEM–X, and OMC observations during the brightest epoch of the outburst, along with complementary NuSTAR, AAVSO, and VSNET data, to examine the timing relationship between the simultaneous optical and X-ray light curves, in order to understand the emission mechanisms and physical locations. Methods. We have identified all optical flares that have simultaneous X-ray observations, and performed a cross-correlation analysis to estimate the time delays between the optical and soft and hard X-ray emission. We also compared the evolution of the optical and X-ray emission with the hardness ratios. Results. We have identified several types of behaviour during the outburst. On many occasions, the optical flares occur simultaneously with X-ray flares, but at other times, positive and negative time delays between the optical and X-ray emission are measured. Conclusions. We conclude that the observed optical variability is driven by different physical mechanisms, including reprocessing of X-rays in the accretion disc and/or the companion star, interaction of the jet ejections with surrounding material or with previously ejected blobs, and synchrotron emission from the jet.

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Camero-Arranz, A., N. Rea, M. A. McLaughlin, et al. "The extended X–ray emission around RRAT J1819–1458." Proceedings of the International Astronomical Union 8, S291 (2012): 261–64. http://dx.doi.org/10.1017/s1743921312023800.

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AbstractWe present new imaging and spectral analysis of the recently discovered extended X–ray emission around the high-magnetic-field rotating radio transient RRAT J1819–1458. We used two Chandra observations, taken on 2008 May 31 and 2011 May 28. The diffuse X–ray emission was detected with a significance of ~19σ in the image obtained by combining the two observations. Long-term spectral variability has not been observed. Possible scenarios for the origin of this diffuse X–ray emission, further detailed in Camero–Arranz et al. (2012), are here discussed.

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Simon, Arleyn W., Destiny L. Crider, Tatsuya Murakami, and Barry Wilkens. "Arizona Salado turquoise: source studies with proton-induced X-ray emission and X-ray diffraction." Open Journal of Archaeometry 1, no. 1 (2013): 10. http://dx.doi.org/10.4081/arc.2013.e10.

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We compare the composition of turquoise source materials from Arizona to prehistoric blue-green stone artifacts recovered from Salado platform mounds (ca. AD 1275-1450) in the Tonto Basin of Central Arizona. Turquoise samples from known source areas in Arizona including Kingman, Castle Dome, in the Globe- Miami area are compare with others that may have been potential sources of turquoise artifacts recovered from the Salado platform mounds. The complementary techniques of proton-induced X-ray emission (PIXE) for chemical analysis and X-ray diffraction (XRD) for mineralogical signatures are used for nondestructive characterisation of both source area samples and archaeological artifacts. The results of the source area sample characterisations are compared quantitatively with the results of archaeological samples, which are evaluated in terms of their likelihood of being from each of the regional sources. The combination of mineralogical and chemical data to identify source materials provides a more thorough identification of the complex variations within turquoise related materials that may not be distinguished by visual inspection. The PIXE and XRD analysis are compared using a set of multivariate statistics including principal components analysis and discriminant analysis. Additionally, a set of Munsell colour charts specifically for the blue-green range of colours is used to objectively qualify colour in comparison to chemical and mineralogical signatures, as colour alone is not a reliable indicator of composition. The results provide objective data to assess directionality of procurement of turquoise and regional social and economic ties to better understand Salado regional connections during this dynamic period in the American Southwest.

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Pallavicini, R., and G. Tagliaferri. "X-Ray Emission from Stellar Flares: Exosat Results." International Astronomical Union Colloquium 104, no. 2 (1989): 17–20. http://dx.doi.org/10.1017/s0252921100153710.

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AbstractWe present an overview of recent observations of stellar X-ray flares obtained with the EXOSAT Observatory. We discuss a few examples of flares from M dwarf flare stars, from RS CVn and Algol-type binaries, from single late-type stars (including a G0 dwarf and an A-type visual binary), and from pre-main-sequence objects. We also draw some general conclusions from the pieliminary analysis of the EXOSAT data sample.

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Kuczumow, A., J. A. Helsen, and R. Wouters. "A uniform Laplacian procedure for X-ray fluorescence analysis, electron microprobe and particle-induced X-ray emission." Spectrochimica Acta Part B: Atomic Spectroscopy 47, no. 8 (1992): 971–82. http://dx.doi.org/10.1016/0584-8547(92)80091-t.

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da Silva, Patrícia, R. B. Menezes, and J. E. Steiner. "The nuclear region of NGC 613 – I. Multiwavelength analysis." Monthly Notices of the Royal Astronomical Society 492, no. 4 (2020): 5121–40. http://dx.doi.org/10.1093/mnras/staa007.

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ABSTRACT In this paper, we report a detailed study with a variety of data from optical, near-infrared, X-ray, and radio telescopes of the nuclear region of the galaxy NGC 613 with the aim of understanding its complexity. We detected an extended stellar emission in the nucleus that, at first, appears to be, in the optical band, two stellar nuclei separated by a stream of dust. The active galactic nucleus (AGN) is identified as a variable point-like source between these two stellar components. There is a central hard X-ray emission and an extended soft X-ray emission that closely coincides with the ionization cone, as seen in the [O iii]λ5007 emission. The centroid of the [O i]λ6300 emission does not coincide with the AGN, being shifted by 0.24 arcsec towards the ionization cone; this shift is probably caused by a combination of differential dust extinction together with emission and reflection in the ionization cone. The optical spectra extracted from the central region are typical of low-ionization nuclear emission-line regions. We also identify 10 H ii regions, eight of them in a star-forming ring that is visible in Br γ, [Fe ii]λ16436, and molecular CO(3-2) images observed in previous studies. Such a ring also presents weak hard X-ray emission, probably associated with supernova remnants, not detected in other studies. The position of the AGN coincides with the centre of a nuclear spiral (detected in previous works) that brings gas and dust from the bar to the nucleus, causing the high extinction in this area.

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Bolotin, V. A., I. N. Burdonskii, V. V. Gavrilov, et al. "Experimental study of X-ray emission from laser-irradiated planar targets on “Mishen” Facility." Laser and Particle Beams 10, no. 4 (1992): 753–58. http://dx.doi.org/10.1017/s0263034600004699.

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X-ray emission from planar targets irradiated by 1.054-μm laser pulses was observed with temporal, spatial, and spectral resolution. The main purpose of these measurements was the investigation of energy transfer in multilayer targets and X-ray conversion efficiency. A mass ablation rate was determined from temporal analysis of multicharged ion line emission and a key role of corona X-ray emission in accelerated material preheating was established.

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Petric, Marko, Rok Bohinc, Klemen Bučar, Matjaž Žitnik, Jakub Szlachetko, and Matjaž Kavčič. "Chemical State Analysis of Phosphorus Performed by X-ray Emission Spectroscopy." Analytical Chemistry 87, no. 11 (2015): 5632–39. http://dx.doi.org/10.1021/acs.analchem.5b00782.

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Röβiger, V. "A Simple Treatment of Secondary Excitation in X-Ray Emission Analysis." Isotopenpraxis Isotopes in Environmental and Health Studies 23, no. 9 (1987): 325–28. http://dx.doi.org/10.1080/10256018708623833.

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Lowe, T., Q. Chen, Q. Fernando, R. Keith, and A. J. Gandolfi. "Elemental analysis of renal slices by proton-induced X-ray emission." Environmental Health Perspectives 101, no. 4 (1993): 302–8. http://dx.doi.org/10.1289/ehp.93101302.

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Loureiro, Silvia R., Fernando Silveira, Gilvan P. Pires, et al. "Analysis of supported zirconocenes by x-ray emission and absorption techniques." X-Ray Spectrometry 34, no. 2 (2005): 101–5. http://dx.doi.org/10.1002/xrs.753.

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GAZZOLA, J., M. SÁNCHEZ DEL RÍO, C. SOLÍS, and T. CALLIGARO. "PARTICLE-INDUCED X-RAY EMISSION (PIXE) ANALYSIS OF OBSIDIAN FROM TEOTIHUACAN." Archaeometry 52, no. 3 (2009): 343–54. http://dx.doi.org/10.1111/j.1475-4754.2009.00483.x.

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VIJAYAN, V., V. S. RAMAMURTHY, and S. N. BEHERA. "PARTICLE-INDUCED X-RAY EMISSION (PIXE) ANALYSIS OF COAL FLY ASH." International Journal of PIXE 05, no. 04 (1995): 211–19. http://dx.doi.org/10.1142/s0129083595000253.

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Analysis of trace element in coal fly ash has been brought to the attention of the general public in recent years primarily as it concerns in pollution problem with coal-fired power plants. Indian coal used in the thermal power plants has quite high content of ash (upto 55%). Therefore, in order to assess the environmental impact of the coal fuel cycle, coal fly ash samples from Captive Power Plant (CPP) of National Aluminium Company (NALCO) in Angul industrial area have been analysed for heavy elements by PIXE technique. Sample preparation procedures, experimental setup and spectrum analysis are discussed.

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