Article
Physics, Multidisciplinary
N. J. Hartley, J. Grenzer, L. Huang, Y. Inubushi, N. Kamimura, K. Katagiri, R. Kodama, A. Kon, W. Lu, M. Makita, T. Matsuoka, S. Nakajima, N. Ozaki, T. Pikuz, A. Rode, D. Sagae, A. K. Schuster, K. Tono, K. Voigt, J. Vorberger, T. Yabuuchi, E. E. McBride, D. Kraus
Summary: The experiment used a high-intensity x-ray pump to heat silicon samples, observing changes in ionic structure within 100 femtoseconds, resulting in a disordered, liquidlike state. The findings indicate that both phase change and disordered states are dominated by Coulomb forces rather than pure inertial behavior.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
B. De Marco, A. A. Zdziarski, G. Ponti, G. Migliori, T. M. Belloni, A. Segovia Otero, M. A. Dzielak, E. Lai
Summary: The study systematically examines the X-ray spectral-timing of the black hole X-ray binary system MAXI J1820+070, focusing on its outburst evolution. It finds that the frequency of thermal reverberation lags steadily increases throughout most of the outburst, indicating a decrease in the relative distance between the X-ray source and the disc as the source softens.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
G. Q. Ding, T. T. Chen, J. L. Qu
Summary: The study systematically searches for hard X-ray tails in the X-ray spectra of Scorpius X-1 from 1996 to 2012, finding their presence is not confined to a specific position on the hardness-intensity diagram. The analysis suggests that the hard X-ray tail becomes harder and its flux decreases as the source transitions from the horizontal branch to the flaring branch on the diagram.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Multidisciplinary Sciences
Yu Zhang, Thomas Kroll, Clemens Weninger, Yurina Michine, Franklin D. Fuller, Diling Zhu, Roberto Alonso-Mori, Dimosthenis Sokaras, Alberto A. Lutman, Aliaksei Halavanau, Claudio Pellegrini, Andrei Benediktovitch, Makina Yabashi, Ichiro Inoue, Yuichi Inubushi, Taito Osaka, Jumpei Yamada, Ganguli Babu, Devashish Salpekar, Farheen N. Sayed, Pulickel M. Ajayan, Jan Kern, Junko Yano, Vittal K. Yachandra, Hitoki Yoneda, Nina Rohringer, Uwe Bergmann
Summary: Coherent nonlinear spectroscopies and imaging in the X-ray domain provide direct insight into the coupled motions of electrons and nuclei with resolution on the electronic length scale and timescale. The experimental realization of such techniques will strongly benefit from access to intense, coherent pairs of femtosecond X-ray pulses. We have observed phase-stable X-ray pulse pairs containing more than 3 x 107 photons at 5.9 keV (2.1 angstrom) with similar to 1 fs duration and 2 to 5 fs separation. The highly directional pulse pairs are manifested by interference fringes in the superfluorescent and seeded stimulated manganese K alpha emission induced by an X-ray free-electron laser. The fringes constitute the time-frequency X-ray analog of Young's double-slit interference, allowing for frequency domain X-ray measurements with attosecond time resolution.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Engineering, Biomedical
David Girou, Eric Ford, Colin Wade, Casper van Aarle, Alexei Uliyanov, Lorraine Hanlon, John A. Tomsick, Andreas Zoglauer, Maximilien J. Collon, Marco W. Beijersbergen, Nicolas M. Barriere
Summary: The study presents a novel optical system for radiation therapy using a Laue lens with Silicon Laue components that concentrate photons to achieve high dose rates at the focal area, leading to simpler and cost-effective treatment units. Monte Carlo simulations show high dose deposition rates in a cylindrical volume with significant dose ratio differences between the surface and the focus. Ongoing work focuses on improving dose rates using newer crystal technologies.
PHYSICS IN MEDICINE AND BIOLOGY
(2021)
Article
Astronomy & Astrophysics
Juan Camilo Buitrago-Casas, Lindsay Glesener, Steven Christe, Sam Krucker, Juliana Vievering, P. S. Athiray, Sophie Musset, Lance Davis, Sasha Courtade, Gregory Dalton, Paul Turin, Zoe Turin, Brian Ramsey, Stephen Bongiorno, Daniel Ryan, Tadayuki Takahashi, Kento Furukawa, Shin Watanabe, Noriyuki Narukage, Shin-nosuke Ishikawa, Ikuyuki Mitsuishi, Kouichi Hagino, Van Shourt, Jessie Duncan, Yixian Zhang, Stuart D. Bale
Summary: This study presents constraints on the quiet-Sun HXR emission in the 5-10 keV range using FOXSI-2 and -3 observations. It reports upper limits for the HXR emission and compares the results with those obtained from RHESSI observations. FOXSI achieved similar results with significantly less observation time compared to RHESSI.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Roman A. Krivonos, Sergey Yu Sazonov, Ekaterina A. Kuznetsova, Alexander A. Lutovinov, Ilya A. Mereminskiy, Sergey S. Tsygankov
Summary: The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) has been observing the sky at energies E > 20 keV since its launch in 2002. The mission has discovered numerous hard X-ray sources and conducted a deep survey of the Galaxy and extragalactic fields. The results show a large number of detected sources, including X-ray binaries, cataclysmic variables, active galactic nuclei, and unclassified sources.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Marta A. Dzielak, Barbara De Marco, Andrzej A. Zdziarski
Summary: The study reveals a complex structure of the accretion flow in the hard state of black hole X-ray binary MAXI J1820+070, requiring at least two Comptonization zones with different temperatures and optical depths to explain the data.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
M. Falanga, A. M. Bykov, Z. Li, A. M. Krassilchtchikov, A. E. Petrov, E. Bozzo
Summary: By analyzing the phase-resolved spectra of LS 5039, it was found that there is a significant spectral hardening above 50 keV, and a spectral break observed in both major phases may indicate an upturn in the spectrum of accelerated leptons, potentially originating from the interaction between wind from the O6.5V companion star and the relativistic outflow from an unidentified compact object.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Victor Tkachenko, Malik M. Abdullah, Zoltan Jurek, Nikita Medvedev, Vladimir Lipp, Mikako Makita, Beata Ziaja
Summary: This study analyzed the application of X-ray diffraction imaging techniques in following ultrafast structural transitions in solid materials. It was found that due to the spatially non-uniform profile of the X-ray beam, the diffraction signal recorded cannot always be interpreted as the material's response to a pulse of a specific fluence. This observation is crucial for planning and interpreting future experiments investigating structural changes in materials using X-ray diffraction imaging.
APPLIED SCIENCES-BASEL
(2021)
Article
Astronomy & Astrophysics
Muriel Zoe Stiefel, Andrea Francesco Battaglia, Krzysztof Barczynski, Hannah Collier, Anna Volpara, Paolo Massa, Conrad Schwanitz, Sofia Tynelius, Louise Harra, Saem Krucker
Summary: In this study, a multiwavelength analysis of a GOES M1.8 flare was presented. Four nonthermal hard X-ray sources were observed, two located outside the flare loop and two at the loop ends. It was found that the outer sources are anchor points of an erupting filament and the hard X-ray emission is due to flare-accelerated electrons injected into the filament.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
H. Stiele, A. K. H. Kong
Summary: We investigated the evolution of quasi-periodic oscillations (QPOs) and noise components using power-density spectra in five snapshots of NICER observations of the black hole transient GX 339-4 during its transition from the hard state to the soft state. We found a strong correlation between the hardness ratio and the type of QPO observed, suggesting a connection between the accretion geometry and spectral properties. We also observed that the type-B QPO undergoes a decoherence process during the transition between different states.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Jean-Francois Fortin, Marianne Gratton
Summary: This study explores the possibility of using ALPs to explain magnetar hard X-ray spectra and suggests that this scenario could also provide answers to magnetar heating related questions. The research finds that explaining the hard X-ray spectra with ALPs could decrease the core temperatures and neutrino emissivities of magnetars, allowing for longer lifetimes as expected from observations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Hannah Collier, Laura A. A. Hayes, Andrea F. F. Battaglia, Louise K. K. Harra, Sam Krucker
Summary: The aim of this work is to develop a method to systematically detect and characterise fast-time variations in the non-thermal hard X-ray time profiles of solar flares using high-resolution data from Solar Orbiter's STIX. The HXR time profiles were smoothed using Gaussian Process regression, and then fitted with a linear combination of Gaussians to decompose the time profile and derive key characteristics such as periodicity, full width at half maximum, time evolution, and amplitude.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
James Rodi, E. Jourdain, J. P. Roques
Summary: This study investigates the temporal and spectral evolution of the outburst from MAXI J1535-571 using data from MAXI/GSC and INTEGRAL/SPI. The early spectra show a composite spectrum with a dominant high-energy component above 150 keV. The results suggest that these two components may originate from different locations.
ASTROPHYSICAL JOURNAL
(2022)