Long-term pulse profile study of the Be/X-ray pulsar   SAX J2103.5+4545

We present the evolution of the X-ray emission properties of the magnetar 1E 1547.0–5408 since February 2004 over a time period covering three outbursts. We analyzed new and archival observations taken with the Swift, NuSTAR, Chandra, and XMM–Newton X-ray satellites. The source has been observed at a relatively steady soft X-ray flux of ≈10−11 erg cm−2 s−1 (0.3–10 keV) over the last 9 years, which is about an order of magnitude fainter than the flux at the peak of the last outburst in 2009, but a factor of ∼30 larger than the level in 2006. The broad-band spectrum extracted from two recent NuSTAR observations in April 2016 and February 2019 showed a faint hard X-ray emission up to ∼70 keV. Its spectrum is adequately described by a flat power law component, and its flux is ∼7 × 10−12 erg cm−2 s−1 (10–70 keV), that is a factor of ∼20 smaller than at the peak of the 2009 outburst. The hard X-ray spectral shape has flattened significantly in time, which is at variance with the overall cooling trend of the soft X-ray component. The pulse profile extracted from these NuSTAR pointings displays variability in shape and amplitude with energy (up to ≈25 keV). Our analysis shows that the flux of 1E 1547.0–5408 is not yet decaying to the 2006 level and that the source has been lingering in a stable, high-intensity state for several years. This might suggest that magnetars can hop among distinct persistent states that are probably connected to outburst episodes and that their persistent thermal emission can be almost entirely powered by the dissipation of currents in the corona.

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Return of the Big Glitcher: NICER timing and glitches of PSR J0537−6910

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2640 ◽

2020 ◽

Vol 498 (4) ◽

pp. 4605-4614

Author(s):

Wynn C G Ho ◽

Cristóbal M Espinoza ◽

Zaven Arzoumanian ◽

Teruaki Enoto ◽

Tsubasa Tamba ◽

...

Keyword(s):

Gravitational Wave ◽

Short Term ◽

Pulse Profile ◽

X Ray ◽

Timing Model ◽

A Value ◽

Rotation Phase ◽

Profile Changes ◽

Strong Gravitational Wave

ABSTRACT PSR J0537−6910, also known as the Big Glitcher, is the most prolific glitching pulsar known, and its spin-induced pulsations are only detectable in X-ray. We present results from analysis of 2.7 yr of NICER timing observations, from 2017 August to 2020 April. We obtain a rotation phase-connected timing model for the entire time span, which overlaps with the third observing run of LIGO/Virgo, thus enabling the most sensitive gravitational wave searches of this potentially strong gravitational wave-emitting pulsar. We find that the short-term braking index between glitches decreases towards a value of 7 or lower at longer times since the preceding glitch. By combining NICER and RXTE data, we measure a long-term braking index n = −1.25 ± 0.01. Our analysis reveals eight new glitches, the first detected since 2011, near the end of RXTE, with a total NICER and RXTE glitch activity of $8.88\times 10^{-7}\, \mathrm{yr^{-1}}$. The new glitches follow the seemingly unique time-to-next-glitch–glitch-size correlation established previously using RXTE data, with a slope of $5\, \rm {d} \, \mu \mathrm{Hz}^{-1}$. For one glitch around which NICER observes 2 d on either side, we search for but do not see clear evidence of spectral nor pulse profile changes that may be associated with the glitch.

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Accreting, highly magnetized neutron stars at the Eddington limit: a study of the 2016 outburst of SMC X-3

Astronomy and Astrophysics ◽

10.1051/0004-6361/201731623 ◽

2018 ◽

Vol 614 ◽

pp. A23 ◽

Cited By ~ 13

Author(s):

Filippos Koliopanos ◽

Georgios Vasilopoulos

Keyword(s):

Neutron Stars ◽

Long Term Evolution ◽

Emission Lines ◽

Pulse Profile ◽

Emission Pattern ◽

X Ray ◽

Term Evolution ◽

Short And Long Term ◽

Eddington Limit

Aims. We study the temporal and spectral characteristics of SMC X-3 during its recent (2016) outburst to probe accretion onto highly magnetized neutron stars (NSs) at the Eddington limit. Methods. We obtained XMM-Newton observations of SMC X-3 and combined them with long-term observations by Swift. We performed a detailed analysis of the temporal and spectral behavior of the source, as well as its short- and long-term evolution. We have also constructed a simple toy-model (based on robust theoretical predictions) in order to gain insight into the complex emission pattern of SMC X-3. Results. We confirm the pulse period of the system that has been derived by previous works and note that the pulse has a complex three-peak shape. We find that the pulsed emission is dominated by hard photons, while at energies below ~1 keV, the emission does not pulsate. We furthermore find that the shape of the pulse profile and the short- and long-term evolution of the source light-curve can be explained by invoking a combination of a “fan” and a “polar” beam. The results of our temporal study are supported by our spectroscopic analysis, which reveals a two-component emission, comprised of a hard power law and a soft thermal component. We find that the latter produces the bulk of the non-pulsating emission and is most likely the result of reprocessing the primary hard emission by optically thick material that partly obscures the central source. We also detect strong emission lines from highly ionized metals. The strength of the emission lines strongly depends on the phase. Conclusions. Our findings are in agreement with previous works. The energy and temporal evolution as well as the shape of the pulse profile and the long-term spectra evolution of the source are consistent with the expected emission pattern of the accretion column in the super-critical regime, while the large reprocessing region is consistent with the analysis of previously studied X-ray pulsars observed at high accretion rates. This reprocessing region is consistent with recently proposed theoretical and observational works that suggested that highly magnetized NSs occupy a considerable fraction of ultraluminous X-ray sources.

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Temporal behavior of Hercules X-1 - The long-term variability of its pulse profile and the 35 day X-ray intensity modulation

The Astrophysical Journal ◽

10.1086/168271 ◽

1990 ◽

Vol 348 ◽

pp. 634 ◽

Cited By ~ 12

Author(s):

Y. Soong ◽

D. E. Gruber ◽

L. E. Peterson ◽

R. E. Rothschild

Keyword(s):

Intensity Modulation ◽

Temporal Behavior ◽

Pulse Profile ◽

X Ray

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Preparation And elemental analysis of ancient fibers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126846 ◽

1987 ◽

Vol 45 ◽

pp. 410-411

Author(s):

Allen Angel ◽

Kathryn A. Jakes

Keyword(s):

Cross Sections ◽

Physical Structure ◽

Energy Dispersive ◽

Archaeological Sites ◽

X Ray ◽

Long Term Storage ◽

Backscattered Electron ◽

Electron Imaging

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.

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Long-term variations in individual particle types in the aerosol of Phoenix, Arizona, as determined using automated electron microprobe analysis and multivariate statistical techniques

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100149544 ◽

1993 ◽

Vol 51 ◽

pp. 742-743

Author(s):

Karen A. Katrinak ◽

James R. Anderson ◽

Peter R. Buseck

Keyword(s):

Electron Microprobe ◽

Fine Fraction ◽

Coarse Fraction ◽

Motor Vehicles ◽

Multivariate Statistical Methods ◽

Multivariate Statistical ◽

X Ray ◽

Mineral Particles ◽

Anthropogenic Air Pollutants

Aerosol samples were collected in Phoenix, Arizona on eleven dates between July 1989 and April 1990. Elemental compositions were determined for approximately 1000 particles per sample using an electron microprobe with an energy-dispersive x-ray spectrometer. Fine-fraction samples (particle cut size of 1 to 2 μm) were analyzed for each date; coarse-fraction samples were also analyzed for four of the dates.The data were reduced using multivariate statistical methods. Cluster analysis was first used to define 35 particle types. 81% of all fine-fraction particles and 84% of the coarse-fraction particles were assigned to these types, which include mineral, metal-rich, sulfur-rich, and salt categories. "Zero-count" particles, consisting entirely of elements lighter than Na, constitute an additional category and dominate the fine fraction, reflecting the importance of anthropogenic air pollutants such as those emitted by motor vehicles. Si- and Ca-rich mineral particles dominate the coarse fraction and are also numerous in the fine fraction.

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Study of Natural Minerals of U-Ryrochlore-Type Structure as Analogues of Plutonium Ceramic Waste-form

MRS Proceedings ◽

10.1557/proc-713-jj2.2 ◽

2002 ◽

Vol 713 ◽

Cited By ~ 1

Author(s):

Roman V. Bogdanov ◽

Yuri F. Batrakov ◽

Elena V. Puchkova ◽

Andrey S. Sergeev ◽

Boris E. Burakov

Keyword(s):

Chemical Shifts ◽

Pyrochlore Structure ◽

Type Structure ◽

Waste Form ◽

X Ray ◽

Ceramic Waste ◽

Natural Minerals ◽

The Us ◽

Pyrochlore Type

ABSTRACTAt present, crystalline ceramic based on titanate pyrochlore, (Ca,Gd,Hf,Pu,U)2Ti2O7, is considered as the US candidate waste form for the immobilization of weapons grade plutonium. Naturally occuring U-bearing minerals with pyrochlore-type structure: hatchettolite, betafite, and ellsworthite, were studied in orders to understand long-term radiation damage effects in Pu ceramic waste forms. Chemical shifts (δ) of U(Lδ1)– and U(Lβ1) – X-ray emission lines were measured by X-ray spectrometry. Calculations were performed on the basis of a two-dimensional δLá1- and δLδ1- correlation diagram. It was shown that 100% of uranium in hatchettolite and, probably, 95-100% of uranium in betafite are in the form of (UO2)2+. formal calculation shows that in ellsworthite only 20% of uranium is in the form of U4+ and 80% of the rest is in the forms of U5+ and U6+. The conversion of the initial U4+ ion originally occurring in the pyrochlore structure of natural minerals to (UO2)2+ due to metamict decay causes a significant increase in uranium mobility.

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Analysis of crystallite size changes in a hematite and magnetite formed on steel used in the power idustry

Technical Sciences ◽

10.31648/ts.2717 ◽

2017 ◽

Vol 1 (21) ◽

pp. 65-73

Author(s):

Monika Gwoździk

Keyword(s):

Elevated Temperature ◽

Oxide Layer ◽

Cross Section ◽

X Ray ◽

Term Operation ◽

Diffraction Line Profile ◽

Crystallite Sizes ◽

Scherrer Formula ◽

Pipe Outlet

The paper presents results of studies on the crystallite sizes of oxide layer formed during a long-term operation on 10CrMo9-10 steel at an elevated temperature (T = 545° C, t = 200,000 h). This value was determined by a method based on analysis of the diffraction line profile, according to a Scherrer formula. The oxide layer was studied on a surface and a cross-section at the outer and inner site on the pipe outlet, at the fire and counter-fire wall of the tube. X-ray studies were carried out on the surface of a tube, then the layer’s surface was polished and the diffraction measurements repeated to reveal differences in the originated oxides layer.

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Enhancing carbonation and chloride resistance of autoclaved concrete by incorporating nano-CaCO3

Nanotechnology Reviews ◽

10.1515/ntrev-2020-0078 ◽

2020 ◽

Vol 9 (1) ◽

pp. 998-1008

Author(s):

Guo Li ◽

Zheng Zhuang ◽

Yajun Lv ◽

Kejin Wang ◽

David Hui

Keyword(s):

Cement Hydration ◽

Mercury Intrusion Porosimetry ◽

Hardened Concrete ◽

Optimal Dosage ◽

Hydration Products ◽

X Ray Diffraction ◽

Carbonation Depth ◽

X Ray ◽

Chloride Resistance

AbstractThree nano-CaCO3 (NC) replacement levels of 1, 2, and 3% (by weight of cement) were utilized in autoclaved concrete. The accelerated carbonation depth and Coulomb electric fluxes of the hardened concrete were tested periodically at the ages of 28, 90, 180, and 300 days. In addition, X-ray diffraction, thermogravimetry, and mercury intrusion porosimetry were also performed to study changes in the hydration products of cement and microscopic pore structure of concrete under autoclave curing. Results indicated that a suitable level of NC replacement exerts filling and accelerating effects, promotes the generation of cement hydration products, reduces porosity, and refines the micropores of autoclaved concrete. These effects substantially enhanced the carbonation and chloride resistance of the autoclaved concrete and endowed the material with resistances approaching or exceeding that of standard cured concrete. Among the three NC replacement ratios, the 3% NC replacement was the optimal dosage for improving the long-term carbonation and chloride resistance of concrete.

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The Effect of Long-Term Impact of Elevated Temperature on Changes in Microstructure and Mechanical Properties of HR3C Steel

Archives of Metallurgy and Materials ◽

10.1515/amm-2016-0129 ◽

2016 ◽

Vol 61 (2) ◽

pp. 761-766 ◽

Cited By ~ 17

Author(s):

A. Zieliński ◽

M. Sroka ◽

A. Hernas ◽

M. Kremzer

Keyword(s):

Mechanical Properties ◽

Elevated Temperature ◽

X Ray ◽

Qualitative And Quantitative ◽

Microstructure And Mechanical Properties ◽

Transmission Electron ◽

Quantitative Identification ◽

Working Parameters ◽

Long Term Impact

Abstract The HR3C is a new steel for pressure components used in the construction of boilers with supercritical working parameters. In the HR3C steel, due to adding Nb and N, the compounds such as MX, CrNbN and M23C6 precipitate during service at elevated temperature, resulting in changes in mechanical properties. This paper presents the results of microstructure investigations after ageing at 650, 700 and 750 °C for 5,000 h. The microstructure investigations were carried out using scanning and transmission electron microscopy. The qualitative and quantitative identification of the existing precipitates was carried out using X-ray analysis of phase composition. The effect elevated temperature on microstructure and mechanical properties of the examined steel was described.

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