scholarly journals The obscured X-ray binaries V404 Cyg, Cyg X–3, V4641 Sgr, and GRS 1915+105

2020 ◽  
Vol 639 ◽  
pp. A13 ◽  
Author(s):  
K. I. I. Koljonen ◽  
J. A. Tomsick
Keyword(s):  
Large Scale ◽  
Surrounding Medium ◽  
The Other ◽  
Opening Angle ◽  
Spectral Evolution ◽  
Time Resolved ◽  
Orbital Inclination ◽  
X Ray ◽  
Geometrical Change ◽  
X Ray Binaries

Aims. V404 Cyg, Cyg X–3, V4641 Sgr, and GRS 1915+105 are among the brightest X-ray binaries and display complex behavior in their multiwavelength emission. Except for Cyg X–3, the other three sources have large accretion disks, and there is evidence of a high orbital inclination. Therefore, any large-scale geometrical change in the accretion disk can cause local obscuration events. On the other hand, Cyg X–3 orbits its Wolf-Rayet companion star inside the heavy stellar wind obscuring the X-ray source. We study here whether the peculiar X-ray spectra observed from all four sources can be explained by local obscuration events. Methods. We used spectra obtained with the Nuclear Spectroscopic Telescope Array and Rossi X-ray Timing Explorer to study the spectral evolution of the four luminous hard X-ray sources. We fit the time-averaged spectra, and also time-resolved spectra in case of V404 Cyg, with two physically motivated models describing either a scenario where all the intrinsic emission is reprocessed in the surrounding matter or where the emitter is surrounded by a thick torus with variable opening angle. Results. We show that the X-ray spectra during specific times are very similar in all four sources, likely arising from the high-density environments where they are embedded. The fitted models suggest that a low-luminosity phase preceding an intense flaring episode in the 2015 outburst of V404 Cyg is heavily obscured, but intrinsically very bright (super-Eddington) accretion state. Similar spectral evolution to that of V404 Cyg is observed from the recent X-ray state of GRS 1915+105 that presented unusually low luminosity. The modeling results point to a geometry change in the (outflowing) obscuring matter in V404 Cyg and GRS 1915+105, which is also linked to the radio (jet) evolution. Within the framework of the models, all sources display obscured X-ray emission, but with different intrinsic luminosities ranging from lower than 1% of the Eddington luminosity up to the Eddington limit. This indicates that different factors cause the obscuration. This work highlights the importance of taking the reprocessing of the X-ray emission in the surrounding medium into account in modeling the X-ray spectra. This may well take place in other sources as well.

scholarly journals Time-Resolved X-Ray Microscopy for Materials Science

2019 ◽  
Vol 49 (1) ◽  
pp. 389-415 ◽  
Author(s):  
Haidan Wen ◽  
Mathew J. Cherukara ◽  
Martin V. Holt
Keyword(s):  
Large Scale ◽  
Materials Science ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Imaging ◽  
Materials Research ◽  
Microscopic Studies ◽  
Nanoscale Imaging ◽  
Indispensable Tool ◽  
The Time Domain

X-ray microscopy has been an indispensable tool to image nanoscale properties for materials research. One of its recent advances is extending microscopic studies to the time domain to visualize the dynamics of nanoscale phenomena. Large-scale X-ray facilities have been the powerhouse of time-resolved X-ray microscopy. Their upgrades, including a significant reduction of the X-ray emittance at storage rings (SRs) and fully coherent ultrashort X-ray pulses at free-electron lasers (FELs), will lead to new developments in instrumentation and will open new scientific opportunities for X-ray imaging of nanoscale dynamics with the simultaneous attainment of unprecedentedly high spatial and temporal resolutions. This review presents recent progress in and the outlook for time-resolved X-ray microscopy in the context of ultrafast nanoscale imaging and its applications to condensed matter physics and materials science.

scholarly journals Short X-ray pulses from third-generation light sources

2016 ◽  
Vol 23 (1) ◽  
pp. 141-151 ◽  
Author(s):  
A. G. Stepanov ◽  
C. P. Hauri
Keyword(s):  
Large Scale ◽  
Light Sources ◽  
Third Generation ◽  
Time Duration ◽  
Pulse Emission ◽  
Time Resolved ◽  
High Brightness ◽  
X Ray ◽  
Synchrotron Light ◽  
Synchrotron Light Sources

High-brightness X-ray radiation produced by third-generation synchrotron light sources (TGLS) has been used for numerous time-resolved investigations in many different scientific fields. The typical time duration of X-ray pulses delivered by these large-scale machines is about 50–100 ps. A growing number of time-resolved studies would benefit from X-ray pulses with two or three orders of magnitude shorter duration. Here, techniques explored in the past for shorter X-ray pulse emission at TGLS are reviewed and the perspective towards the realisation of picosecond and sub-picosecond X-ray pulses are discussed.

scholarly journals Revealing the Physical Changes Taking Place in Z-Track Motion in Low Mass X-Ray Binaries

2004 ◽  
Vol 194 ◽  
pp. 206-206
Author(s):  
M. Bałucińska-Church ◽  
M. J. Church ◽  
G. Halai ◽  
A. Szostek
Keyword(s):  
Neutron Star ◽  
Emission Model ◽  
Spectral Evolution ◽  
X Ray ◽  
Astrophysical Problem ◽  
Low Mass ◽  
Physical Changes ◽  
First Time ◽  
X Ray Binaries

The explanation of the strong physical changes clearly taking place in the Z-track class of Low Mass X-ray Binaries has so far not been obtained, and this remains a significant astrophysical problem, without which we cannot claim to understand accretion in LMXB. We have for the first time applied the Birmingham emission model (2,3) to this problem to attempt to obtain a solution from the spectral evolution along the Z-track in the source GX 340+0 observed with Rossi- ХTE. In this model, X-ray emission consists of blackbody from the neutron star, plus Comptonized emission from an extended ADC.

scholarly journals High-Energy X-Ray Compton Scattering Imaging of 18650-Type Lithium-Ion Battery Cell

2019 ◽  
Vol 4 (3) ◽  
pp. 66 ◽  
Author(s):  
Kosuke Suzuki ◽  
Ari-Pekka Honkanen ◽  
Naruki Tsuji ◽  
Kirsi Jalkanen ◽  
Jari Koskinen ◽  
...  
Keyword(s):  
Energy Spectrum ◽  
Lithium Ion Battery ◽  
Compton Scattering ◽  
Present Method ◽  
Large Scale ◽  
Lithium Ion ◽  
High Energy ◽  
The Other ◽  
Battery Cell ◽  
X Ray

High-energy synchrotron X-ray Compton scattering imaging was applied to a commercial 18650-type cell, which is a cylindrical lithium-ion battery in wide current use. By measuring the Compton scattering X-ray energy spectrum non-destructively, the lithiation state in both fresh and aged cells was obtained from two different regions of the cell, one near the outer casing and the other near the center of the cell. Our technique has the advantage that it can reveal the lithiation state with a micron-scale spatial resolution even in large cells. The present method enables us to monitor the operation of large-scale cells and can thus accelerate the development of advanced lithium-ion batteries.

In Situ Time-Resolved X-Ray Diffraction Investigation of the ω→ψ Transition in Al-Cu-Fe Quasicrystal-Forming Alloys

2007 ◽  
Vol 558-559 ◽  
pp. 943-947 ◽  
Author(s):  
E. Otterstein ◽  
R. Nicula ◽  
J. Bednarčík ◽  
M. Stir ◽  
E. Burkel
Keyword(s):  
Large Scale ◽  
Applied Pressure ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
In Situ Xrd ◽  
Kinetics Of

Quasicrystals are aperiodic long-range ordered solids with a high potential for many modern applications. Interest is nowadays paid to the development of economically viable large-scale synthesis procedures of quasicrystalline materials involving solid-state transformations. The kinetics of the high-temperature phase transition from the complex ω-phase to the icosahedral quasicrystalline (iQC) ψ-phase in AlCuFe nanopowders was here examined by in-situ time-resolved X-ray diffraction experiments using synchrotron radiation. In-situ XRD experiments will allow insight on the influence of uniaxial applied pressure on the kinetics of phase transitions leading to the formation of single-phase QC nanopowders and further contribute to the optimization of sintering procedures for nano-quasicrystalline AlCuFe alloy powders.

scholarly journals Probing the X-ray Variability of X-ray Binaries

2003 ◽  
Vol 214 ◽  
pp. 236-239
Author(s):  
Wenfei Yu
Keyword(s):  
Neutron Star ◽  
Light Curve ◽  
Time Scale ◽  
Accretion Rate ◽  
Power Spectra ◽  
The Other ◽  
Periodic Oscillations ◽  
X Ray ◽  
Orbital Frequency ◽  
X Ray Binaries

Kilohertz quasi-periodic oscillations (kHz QPOs) has been regarded as representing the Keplerian frequency at the inner disk edge in the neutron star X-ray binaries. The so-called “parallel tracks” on the plot of the kHz QPO frequency vs. X-ray flux in neutron star X-ray binaries, on the other hand, show the correlation between the kHz QPO frequency and the X-ray flux on time scales from hours to days. This is suspected as caused by the variations of the mass accretion rate through the accretion disk surrounding the neutron star. We show here that by comparing the correlation between the kHz QPO frequency and the X-ray count rate on a certain QPO time scale observed approximately simultaneous in the Fourier power spectra of the X-ray light curve, we have found evidences that the X-ray flux of millihertz QPOs in neutron star X-ray binaries is generated inside the inner disk edge if adopting that the kilohertz QPO frequency is an orbital frequency at the inner disk edge.

scholarly journals Polarimetry of Close Binary Systems; Observations and Interpretations

1980 ◽  
Vol 88 ◽  
pp. 65-70
Author(s):  
Ian S. McLean
Keyword(s):  
Binary Systems ◽  
Stokes Parameters ◽  
Close Binary ◽  
Stellar Winds ◽  
Line Profiles ◽  
Orbital Inclination ◽  
X Ray ◽  
Close Binary Systems ◽  
A New Technique ◽  
X Ray Binaries

Polarization caused by scattering of starlight on gaseous extrastellar material in close binary systems is reviewed. A simple physical derivation is given to illustrate how in principle, variations synchronous with the orbital period of the Stokes parameters of the linear polarization can yield the orbital inclination and other parameters. High resolution multichannel spectropolarimetry across the emission line profiles of binaries is discussed as a new technique in studying the physics and kinematics of gaseous streams and stellar winds. The methods have application to a range of binary objects including systems like Algol and Beta Lyrae, X-ray binaries, Of and Wolf-Rayet binaries, VV Cephei stars and symbiotic stars. Some new observational results are presented.

scholarly journals GRS 1758–258: RXTE Monitoring of a Rare Persistent Hard State Black Hole

10.14311/1480 ◽  
2011 ◽  
Vol 51 (6) ◽  
Author(s):  
M. Obst ◽  
K. Pottschmidt ◽  
A. Lohfink ◽  
J. Wilms ◽  
M. Böck ◽  
...  
Keyword(s):  
Black Hole ◽  
State Transitions ◽  
Spectral Evolution ◽  
X Ray ◽  
Soft State ◽  
Hard State ◽  
Long Term Behavior ◽  
X Ray Binaries ◽  
Black Hole Candidates

GRS 1758–258 is the least studied of the three persistent black hole X-ray binaries in our Galaxy. It is also one of only two known black hole candidates, including all black hole transients, which shows a decrease of its 3-10 keV flux when entering the thermally dominated soft state, rather than an increase.We present the spectral evolution of GRS 1758–258 from RXTE-PCA observations spanning a time of about 11 years from 1996 to 2007. During this time, seven dim soft states are detected. We also consider INTEGRAL monitoring observations of the source and compare the long-term behavior to that of the bright persistent black hole X-ray binary Cygnus X-1. We discuss the observed state transitions in the light of physical scenarios for black hole transitions.

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