arXiv subjects

K. Mori

Publications and source records attributed to K. Mori.

At least 19 recordsLinked to original sources

arXiv2025

A XRISM/Resolve view of the dynamics in the hot gaseous atmosphere of M87

The XRISM/Resolve microcalorimeter directly measured the gas velocities in the core of the Virgo Cluster, the closest example of AGN feedback in a cluster. This proximity allows us to resolve the kinematic impact of feedback on scales down to 5 kpc. Our spectral analysis reveals a high velocity dispersion of $\sigma_v$=262 (+45 / -38) km/s near the AGN, which steeply declines to ~60 km/s between 5 and 25 kpc in the northwest direction. The observed line-of-sight bulk velocity in all regions is broadly consistent with the central galaxy, M87, with a mild trend toward blueshifted motions at larger radii. Systematic uncertainties have been carefully assessed and do not affect the measurements. The central velocities, if attributed entirely to isotropic turbulence, correspond to a transonic ICM at sub-6 kpc scales with three-dimensional Mach number 0.69 (+0.14 / -0.11) and a non-thermal pressure fraction of 21 (+7 / -5)%. Simple models of weak shocks and sound waves and calculations assuming isotropic turbulence both support the hypothesis that the velocity field reflects a mix of shock-driven expansion and turbulence. Compared to other clusters observed by XRISM to date, M87's central region stands out as the most kinematically disturbed, exhibiting both the highest velocity dispersion and the largest 3D Mach number, concentrated at the smallest physical scales.

astro-ph.GA↗

arXiv2025

Einstein Probe discovery of the short period intermediate polar EP J115415.8-501810

The X-ray transient source EP240309a/EP\,J115415.8$-$501810 was first detected by the Wide-Field X-ray Telescope (WXT) on board Einstein Probe (EP) during the commissioning phase. Subsequent optical observations confirmed it as a Cataclysmic Variable of the intermediate polar type with a 238.2\,s spinning white dwarf in a $\sim$3.76\,hr orbit. We report on the source discovery and follow-up studies made with the Follow-up X-ray Telescope (FXT) of EP. A periodic variation of 231\,s is detected in the 0.3$-$2\,keV band, while no obvious pulsation appears in the 2$-$10\,keV band. The spectral analysis shows that the X-ray emission could be described by an absorbed bremsstrahlung model with $kT$\textgreater\,11\,keV. The partial covering absorption, with an hydrogen column density $N_H$ = 2.0$\times 10^{22}\,\rm cm^{-2}$ and covering fraction around 0.9, is much larger than the interstellar absorption along the line of sight. According to the distance $d = 309.5$\,pc obtained from Gaia parallax, we estimate that the luminosity of this source in the 0.3$-$10\,keV range is $\sim 2\times10^{32}$\,erg\,s$^{-1}$. In addition, phase-resolved spectral analysis reveals that the detected periodic variation is mainly caused by the change in the absorption column density. In this scenario the spin modulation arises due to absorption from the pre-shock accretion flow of the X-ray emitting pole, while the optical radiation is modulated at the orbital side band ($\omega_{\rm spin} - \Omega_{\rm orbit}$) due to reprocessing in regions within the binary system. Due to its unusual transient behaviour for an intermediate polar, we have also searched for radio signals similar to those observed in the new class of long period transients. We derived upper limits with ASKAP (200--300\,$\mu$Jy\,beam$^{-1}$ between 800--1500 MHz) and MWA (40--90\,mJy\,beam$^{-1}$ between 80--300 MHz).

astro-ph.HE↗

arXiv2025

Multiwavelength observation of a candidate pulsar halo LHAASO J0621+3755 and the first X-ray detection of PSR J0622+3749

Pulsar halos are regions around middle-aged pulsars extending out to tens of parsecs. The large extent of the halos and well-defined central cosmic-ray accelerators make this new class of Galactic sources an ideal laboratory for studying cosmic-ray transport. LHAASO J0621+3755 is a candidate pulsar halo associated with the middle-aged gamma-ray pulsar PSR J0622+3749. We observed LHAASO J0621+3755 with VERITAS and XMM-Newton in the TeV and X-ray bands, respectively. For this work, we developed a novel background estimation technique for imaging atmospheric Cherenkov telescope observations of such extended sources. No halo emission was detected with VERITAS (0.3--10 TeV) or XMM-Newton (2--7 keV) within 1 degree and 10 arcmin around PSR J0622+3749, respectively. Combined with the LHAASO-KM2A and Fermi-LAT data, VERITAS flux upper limits establish a spectral break at ~1--10 TeV, a unique feature compared with Geminga, the most studied pulsar halo. We model the gamma-ray spectrum and LHAASO-KM2A surface brightness as inverse Compton emission and find suppressed diffusion around the pulsar, similar to Geminga. A smaller diffusion suppression zone and harder electron injection spectrum than Geminga are necessary to reproduce the spectral cutoff. A magnetic field <= 1 uG is required by our XMM-Newton observation and synchrotron spectral modeling, consistent with Geminga. Our findings support slower diffusion and lower magnetic field around pulsar halos than the Galactic averages, hinting at magnetohydrodynamic turbulence around pulsars. Additionally, we report the detection of an X-ray point source spatially coincident with PSR J0622+3749, whose periodicity is consistent with the gamma-ray spin period of 333.2 ms. The soft spectrum of this source suggests a thermal origin.

astro-ph.HE↗

arXiv2023

The High Energy X-ray Probe (HEX-P): Magnetars and Other Isolated Neutron Stars

The hard X-ray emission from magnetars and other isolated neutron stars remains under-explored. An instrument with higher sensitivity to hard X-rays is critical to understanding the physics of neutron star magnetospheres and also the relationship between magnetars and Fast Radio Bursts (FRBs). High sensitivity to hard X-rays is required to determine the number of magnetars with hard X-ray tails, and to track transient non-thermal emission from these sources for years post-outburst. This sensitivity would also enable previously impossible studies of the faint non-thermal emission from middle-aged rotation-powered pulsars (RPPs), and detailed phase-resolved spectroscopic studies of younger, bright RPPs. The High Energy X-ray Probe (HEX-P) is a probe-class mission concept that will combine high spatial resolution X-ray imaging ($<5$ arcsec half-power diameter (HPD) at 0.2--25 keV) and broad spectral coverage (0.2--80 keV) with a sensitivity superior to current facilities (including XMM-Newton and NuSTAR). HEX-P has the required timing resolution to perform follow-up observations of sources identified by other facilities and positively identify candidate pulsating neutron stars. Here we discuss how HEX-P is ideally suited to address important questions about the physics of magnetars and other isolated neutron stars.

astro-ph.HE↗

arXiv2023

A multi-wavelength investigation of PSR J2229+6114 and its pulsar wind nebula in the radio, X-ray, and gamma-ray bands

G106.3$+$2.7, commonly considered a composite supernova remnant (SNR), is characterized by a boomerang-shaped pulsar wind nebula (PWN) and two distinct ("head" & "tail") regions in the radio band. A discovery of very-high-energy (VHE) gamma-ray emission ($E_γ> 100$ GeV) followed by the recent detection of ultra-high-energy (UHE) gamma-ray emission ($E_γ> 100$ TeV) from the tail region suggests that G106.3$+$2.7 is a PeVatron candidate. We present a comprehensive multi-wavelength study of the Boomerang PWN (100" around PSR J2229+6114) using archival radio and Chandra data obtained from two decades ago, a new NuSTAR X-ray observation from 2020, and upper limits on gamma-ray fluxes obtained by Fermi and VERITAS observatories. The NuSTAR observation allowed us to detect a 51.67 ms spin period from the pulsar PSR J2229+6114 and the PWN emission characterized by a power-law model with $Γ= 1.52\pm0.06$ up to 20 keV. Contrary to the previous radio study by Kothes et al. 2006, we prefer a much lower PWN B-field ($B\sim3$ $μ$G) and larger distance ($d \sim 8$ kpc) based on (1) the non-varying X-ray flux over the last two decades, (2) the energy-dependent X-ray PWN size resulting from synchrotron burn-off and (3) the multi-wavelength spectral energy distribution (SED) data. Our SED model suggests that the PWN is currently re-expanding after being compressed by the SNR reverse shock $\sim 1000$ years ago. In this case, the head region should be formed by GeV--TeV electrons injected earlier by the pulsar propagating into the low density environment.

astro-ph.HE↗

arXiv2023

Multiwavelength Observations of the Blazar PKS~0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A

We report on multiwavelength target-of-opportunity observations of the blazar PKS 0735+178, located 2.2 degrees away from the best-fit position of the IceCube neutrino event 211208A. The source was in a high-flux state in the optical, ultraviolet, X-ray, and GeV gamma-ray bands around the time of the neutrino event, exhibiting daily variability in the soft X-ray flux. The X-ray data from Swift-XRT and NuSTAR characterize the transition between the low-energy and high-energy components of the broadband spectral energy distribution, and the gamma-ray data from Fermi-LAT, VERITAS, and H.E.S.S. require a spectral cut-off near 100 GeV. Both measurements provide strong constraints on leptonic and hadronic models. We analytically explore a synchrotron self-Compton model, an external Compton model, and a lepto-hadronic model. Models that are entirely based on internal photon fields face serious difficulties in matching the observed spectral energy distribution (SED). The existence of an external photon field in the source would instead explain the observed gamma-ray spectral cut-off in both leptonic and lepto-hadronic models, and it would allow a proton jet power that marginally agrees with the Eddington limit in the lepto-hadronic model. A numerical lepto-hadronic model with external target photons reproduces the observed SED and is reasonably consistent with the neutrino event despite requiring a high jet power.

astro-ph.HE↗

arXiv2023

Scale-dependent analysis of angular momentum flux in high-resolution magnetohydrodynamic simulations for solar differential rotation

In this work, we systematically investigate the scale-dependent angular momentum flux by analysing high-resolution three-dimensional magnetohydrodynamic simulations in which the solar-like differential rotation is reproduced without using any manipulations. More specifically, the magnetic angular momentum transport (AMT) plays a dominant role in the calculations. We examine the important spatial scales for the magnetic AMT. The main conclusions of our approach can be summarized as follows: 1. Turbulence transports the angular momentum radially inward. This effect is more pronounced in the highest resolution calculation. 2. The dominant scale for the magnetic AMT is the smallest spatial scale. 3. The dimensionless magnetic correlation is low in the high-resolution simulation. Thus, chaotic but strong small-scale magnetic fields achieve efficient magnetic AMT.

astro-ph.SR↗

arXiv2023

Exploring Fundamental Particle Acceleration and Loss Processes in Heliophysics through an Orbiting X-ray Instrument in the Jovian System

Jupiter's magnetosphere is considered to be the most powerful particle accelerator in the Solar System, accelerating electrons from eV to 70 MeV and ions to GeV energies. How electromagnetic processes drive energy and particle flows, producing and removing energetic particles, is at the heart of Heliophysics. Particularly, the 2013 Decadal Strategy for Solar and Space Physics was to "Discover and characterize fundamental processes that occur both within the heliosphere and throughout the universe". The Jovian system offers an ideal natural laboratory to investigate all of the universal processes highlighted in the previous Decadal. The X-ray waveband has been widely used to remotely study plasma across astrophysical systems. The majority of astrophysical emissions can be grouped into 5 X-ray processes: fluorescence, thermal/coronal, scattering, charge exchange and particle acceleration. The Jovian system offers perhaps the only system that presents a rich catalog of all of these X-ray emission processes and can also be visited in-situ, affording the special possibility to directly link fundamental plasma processes with their resulting X-ray signatures. This offers invaluable ground-truths for astrophysical objects beyond the reach of in-situ exploration (e.g. brown dwarfs, magnetars or galaxy clusters that map the cosmos). Here, we show how coupling in-situ measurements with in-orbit X-ray observations of Jupiter's radiation belts, Galilean satellites, Io Torus, and atmosphere addresses fundamental heliophysics questions with wide-reaching impact across helio- and astrophysics. New developments like miniaturized X-ray optics and radiation-tolerant detectors, provide compact, lightweight, wide-field X-ray instruments perfectly suited to the Jupiter system, enabling this exciting new possibility.

astro-ph.IM↗

arXiv2022

Investigation of the dependence of angular momentum transport on spatial scales for construction of differential rotation

We investigate the dependence of the angular momentum transport (AMT) on the spatial scales with numerical simulation of solar-like stars. It is thought that turbulence has an essential role in constructing solar differential rotation (DR). In a widely used method to analyse the construction mechanism of DR, the flow is divided into two components, `mean flow' and `turbulence', where `turbulence' includes a broad spectrum of spatial scales. The features of the AMT are expected to depend on the scale. In this study, we decompose the angular momentum flux (AMF) to investigate the dependence of the AMF on the spatial scale. We compare the results with anti-solar- (fast pole) and solar-type (fast equator) DR. Our conclusions are summarized as 1. Radially outward AMT is seen on a large scale (60 Mm < L <120 Mm) in rotationally constrained systems. 2. Even when the scale-integrated AMF is negative, we sometimes observe positive AMF on certain scales. 3. Small-scale turbulence tends to transport the angular momentum radially inward and causes the anti-solar DR, indicating that high-resolution simulation is a negative factor for solar-like DR. Our method to decompose the AMF provides a deep understanding of the angular momentum and construction mechanism of DR.

astro-ph.SR↗

arXiv2021

Multi-Wavelength Observation Campaign of the TeV Gamma-Ray Binary HESS J0632+057 with NuSTAR, VERITAS, MDM, and Swift

HESS J0632+057 belongs to a rare subclass of binary systems which emits gamma-rays above 100 GeV. It stands out for its distinctive high-energy light curve, which features a sharp ``primary'' peak and broader ``secondary'' peak. We present the results of contemporaneous observations by NuSTAR and VERITAS during the secondary peak between Dec. 2019 and Feb. 2020, when the orbital phase ($ϕ$) is between 0.55 and 0.75. NuSTAR detected X-ray spectral evolution, while VERITAS detected TeV emission. We fit a leptonic wind-collision model to the multi-wavelength spectra data obtained over the four NuSTAR and VERITAS observations, constraining the pulsar spin-down luminosity and the magnetization parameter at the shock. Despite long-term monitoring of the source from Oct. 2019 to Mar. 2020, the MDM observatory did not detect significant variation in H$α$ and H$β$ line equivalent widths, an expected signature of Be-disk interaction with the pulsar. Furthermore, fitting folded Swift-XRT light curve data with an intra-binary shock model constrained the orbital parameters, suggesting two orbital phases (at $ϕ_D = 0.13$ and 0.37) where the pulsar crosses the Be-disk, as well as phases for the periastron ($ϕ_0 = 0.30$) and inferior conjunction ($ϕ_{\text{IFC}} = 0.75$). The broad-band X-ray spectra with Swift-XRT and NuSTAR allowed us to measure a higher neutral hydrogen column density at one of the predicted disk-passing phases.

astro-ph.HE↗

arXiv2021

Constraining particle acceleration in Sgr A* with simultaneous GRAVITY, Spitzer, NuSTAR and Chandra observations

We report the time-resolved spectral analysis of a bright near-infrared and moderate X-ray flare of Sgr A*. We obtained light curves in the $M$-, $K$-, and $H$-bands in the mid- and near-infrared and in the $2-8~\mathrm{keV}$ and $2-70~\mathrm{keV}$ bands in the X-ray. The observed spectral slope in the near-infrared band is $νL_ν\propto ν^{0.5\pm0.2}$; the spectral slope observed in the X-ray band is $νL_ν\propto ν^{-0.7\pm0.5}$. We tested synchrotron and synchrotron self-Compton (SSC) scenarios. The observed near-infrared brightness and X-ray faintness, together with the observed spectral slopes, pose challenges for all models explored. We rule out a scenario in which the near-infrared emission is synchrotron emission and the X-ray emission is SSC. A one-zone model in which both the near-infrared and X-ray luminosity are produced by SSC and a model in which the luminosity stems from a cooled synchrotron spectrum can explain the flare. In order to describe the mean SED, both models require specific values of the maximum Lorentz factor $γ_{max}$, which however differ by roughly two orders of magnitude: the SSC model suggests that electrons are accelerated to $γ_{max}\sim 500$, while cooled synchrotron model requires acceleration up to $γ_{max}\sim5\times 10^{4}$. The SSC scenario requires electron densities of $10^{10}~\mathrm{cm^{-3}}$ much larger than typical ambient densities in the accretion flow, and thus require in an extraordinary accretion event. In contrast, assuming a source size of $1R_s$, the cooled synchrotron scenario can be realized with densities and magnetic fields comparable with the ambient accretion flow. For both models, the temporal evolution is regulated through the maximum acceleration factor $γ_{max}$, implying that sustained particle acceleration is required to explain at least a part of the temporal evolution of the flare.

astro-ph.HE↗

arXiv2020

The Einstein - de Haas effect at radio frequencies in and near magnetic equilibrium

The Einstein-de Haas (EdH) effect and its reciprocal the Barnett effect are fundamental to magnetism and uniquely yield measures of the ratio of magnetic moment to total angular momentum. These effects, small and generally difficult to observe, are enjoying a resurgence of interest as contemporary techniques enable new approaches to their study. The high mechanical resonance frequencies in nanomechanical systems offer a tremendous advantage for the observation of EdH torques in particular. At radio frequencies, the EdH effect can become comparable to or even exceed in magnitude conventional cross-product magnetic torques. In addition, the RF-EdH torque is expected to be phase-shifted by 90 degrees relative to cross-product torques, provided the magnetic system remains in quasi-static equilibrium, enabling separation in quadratures when both sources of torque are operative. Radio frequency EdH measurements are demonstrated through the full hysteresis range of micrometer scale, monocrystalline yttrium iron garnet (YIG) disks. Equilibrium behavior is observed in the vortex state at low bias field. Barkhausen-like features emerge in the in-plane EdH torque at higher fields in the vortex state, revealing magnetic disorder too weak to be visible through the in-plane cross-product torque. Beyond vortex annihilation, peaks arise in the EdH torque versus bias field, and these together with their phase signatures indicate additional utility of the Einstein-de Haas effect for the study of RF-driven spin dynamics.

cond-mat.mes-hall↗

arXiv2020

Logarithmic and nonlogarithmic scaling laws of two-point statistics in wall turbulence

Wall turbulence has a sublayer where one-point statistics, e.g., the mean velocity and the variances of some velocity fluctuations, vary logarithmically with the distance from the wall. This logarithmic scaling is found here for two-point statistics or specifically two-point cumulants of those fluctuations by means of experiments in a wind tunnel. As for corresponding statistics of the rate of the energy dissipation, the scaling is found to be not logarithmic. We reproduce these scaling laws with some mathematics and also with a model of energy-containing eddies that are attached to the wall.

physics.flu-dyn↗

arXiv2019

Probing the Properties of the Pulsar Wind in the Gamma-Ray Binary HESS J0632+057 with NuSTAR and VERITAS Observations

HESS J0632+057 is a gamma-ray binary composed of a compact object orbiting a Be star with a period of about $315$ days. Extensive X-ray and TeV gamma-ray observations have revealed a peculiar light curve containing two peaks, separated by a dip. We present the results of simultaneous observations in hard X-rays with NuSTAR and in TeV gamma-rays with VERITAS, performed in November and December 2017. These observations correspond to the orbital phases $ϕ\approx0.22$ and $0.3$, where the fluxes are rising towards the first light-curve peak. A significant variation of the spectral index from 1.77$\pm$0.05 to 1.56$\pm$0.05 is observed in the X-ray data. The multi-wavelength spectral energy distributions (SED) derived from the observations are interpreted in terms of a leptonic model, in which the compact object is assumed to be a pulsar and non-thermal radiation is emitted by high-energy electrons accelerated at the shock formed by the collision between the stellar and pulsar wind. The results of the SED fitting show that our data can be consistently described within this scenario, and allow us to estimate the magnetization of the pulsar wind at the location of the shock formation. The constraints on the pulsar-wind magnetization provided by our results are shown to be consistent with those obtained from other systems.

astro-ph.HE↗

arXiv2019

Sub-pixel Response of Double-SOI Pixel Sensors for X-ray Astronomy

We have been developing the X-ray silicon-on-insulator (SOI) pixel sensor called XRPIX for future astrophysical satellites. XRPIX is a monolithic active pixel sensor consisting of a high-resistivity Si sensor, thin SiO$_2$ insulator, and CMOS pixel circuits that utilize SOI technology. Since XRPIX is capable of event-driven readouts, it can achieve high timing resolution greater than $\sim 10{\rm ~μs}$, which enables low background observation by adopting the anti-coincidence technique. One of the major issues in the development of XRPIX is the electrical interference between the sensor layer and circuit layer, which causes nonuniform detection efficiency at the pixel boundaries. In order to reduce the interference, we introduce a Double-SOI (D-SOI) structure, in which a thin Si layer (middle Si) is added to the insulator layer of the SOI structure. In this structure, the middle Si layer works as an electrical shield to decouple the sensor layer and circuit layer. We measured the detector response of the XRPIX with D-SOI structure at KEK. We irradiated the X-ray beam collimated with $4{\rm ~μmϕ}$ pinhole, and scanned the device with $6{\rm ~μm}$ pitch, which is 1/6 of the pixel size. In this paper, we present the improvement in the uniformity of the detection efficiency in D-SOI sensors, and discuss the detailed X-ray response and its physical origins.

astro-ph.IM↗

arXiv2019

X-ray Monitoring of the Magnetar CXOU J171405.7-381031 in SNR CTB 37B

We present the results of our 8 year X-ray monitoring campaign on CXOU J171405.7-381031, the magnetar associated with the faint supernova remnant (SNR) CTB 37B. It is among the youngest by inferred spin-down age, and most energetic in spin-down power of magnetars, and may contribute, at least partially, to the GeV and TeV emission coincident with the SNR. We use a series of Chandra, XMM-Newton, and NuSTAR observations to characterize the timing and spectral properties of the magnetar. The spin-down rate of the pulsar almost doubled in <1 year and then decreased slowly to a more stable value. Its X-ray flux varied by approx, 50%, possibly correlated with the spin down rate. The 1-79 keV spectrum is well-characterized by an absorbed blackbody plus power-law model with an average temperature of kT=0.62+/-0.04 keV and photon index Gamma=0.92+/-0.16, or by a Comptonized blackbody with kT=0.55+/-0.04 keV and an additional hard power law with Gamma=0.70+/-0.20, In contrast with most magnetars, the pulsed signal is found to decrease with energy up to 6 keV, which is apparently caused by mixing with the hard spectral component that is pulse-phase shifted by approx. 0.43 cycles from the soft X-rays. We also analyze the spectrum of the nearby, diffuse nonthermal source XMMU J171410.8-381442, whose relation to the SNR is uncertain.

astro-ph.HE↗

arXiv2019

Multiwavelength Investigation of Pulsar Wind Nebula DA 495 with HAWC, VERITAS, and NuSTAR

Pulsar Wind Nebula (PWN) DA 495 (G65.7+1.2) was detected in TeV gamma-rays by the High Altitude Water Cherenkov Observatory (HAWC) in 2017 (2HWC J1953+294). Follow-up observations by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) confirmed the association between 2HWC J1953+294 and DA 495 and found the TeV emission to be spatially coincident with the radio emission first reported in 1968. The detection of TeV gamma-rays from DA 495, along with past X-ray detection up to 10 keV, prompted high energy X-ray observations as part of the NuSTAR Galactic Legacy Survey. We present the results of these NuSTAR observations, combined with archival Chandra and XMM-Newton observations, and confirm the previous X-ray photon index of $Γ_{2-20 \rm\ keV} = 2.0 \pm 0.1$. We find no spectral cutoff up to 20 keV. With the spectral information for DA 495 extended to TeV gamma-rays, we were able to perform analytical modeling to test leptonic and hadronic emission scenarios. The leptonic models can explain the broadband emission, but also imply a diffuse X-ray nebula of similar extent to the radio and TeV nebulae, which cannot be confirmed by our observations. The hadronic models can simultaneously explain the spectrum and the spatial extent in all wavelengths; however, we need a very high magnetic field strength pervading the radio and TeV nebulae and a surprisingly high particle kinetic energy. These requirements deepen the mystery of the physical nature of DA 495. Future observations in radio to infrared bands and spatially resolved $γ$-rays can further constrain the physical conditions and radiation mechanisms in DA 495.

astro-ph.HE↗

arXiv2019

Direct Measurement of the Cosmic-Ray Proton Spectrum from 50 GeV to 10 TeV with the Calorimetric Electron Telescope on the International Space Station

In this paper, we present the analysis and results of a direct measurement of the cosmic-ray proton spectrum with the CALET instrument onboard the International Space Station, including the detailed assessment of systematic uncertainties. The observation period used in this analysis is from October 13, 2015 to August 31, 2018 (1054 days). We have achieved the very wide energy range necessary to carry out measurements of the spectrum from 50 GeV to 10 TeV covering, for the first time in space, with a single instrument the whole energy interval previously investigated in most cases in separate subranges by magnetic spectrometers (BESS-TeV, PAMELA, and AMS-02) and calorimetric instruments (ATIC, CREAM, and NUCLEON). The observed spectrum is consistent with AMS-02 but extends to nearly an order of magnitude higher energy, showing a very smooth transition of the power-law spectral index from -2.81 +- 0.03 (50--500 GeV) neglecting solar modulation effects (or -2.87 +- 0.06 including solar modulation effects in the lower energy region) to -2.56 +- 0.04 (1--10 TeV), thereby confirming the existence of spectral hardening and providing evidence of a deviation from a single power law by more than 3 sigma.

astro-ph.HE↗