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Accurate Determination of Chemical Abundances near a Supermassive Black Hole
The XRISM collaboration
The metal abundances in galactic nuclei carry key information on the history of star formation and mass transfer in central regions of galaxies. X-ray fluorescence analysis is a un…
High Spectral Resolution X-ray Observations of the Evolved Supermassive Stellar Binary System Carinae - Iron K Band Profile Revealed with XRISM
XRISM Collaboration, Marc Audard, Hisamitsu Awaki +138
The supermassive binary system, Carinae, is experiencing enormous wind-driven mass loss at a rate unparalleled in the rest of the Galaxy. Their wind-wind collision (WWC) contin…
Chlorine and Potassium Enrichment in the Cassiopeia A Supernova Remnant
XRISM collaboration
The elements in the universe are synthesized primarily in stars and supernovae, where nuclear fusion favors the production of even-Z elements. In contrast, odd-Z elements are less…
XRISM constraints on unidentified X-ray emission lines, including the 3.5 keV line, in the stacked spectrum of ten galaxy clusters
XRISM Collaboration, Marc Audard, Hisamitsu Awaki +150
We stack 3.75 Megaseconds of early XRISM Resolve observations of ten galaxy clusters to search for unidentified spectral lines in the 2.5-15 keV band (rest frame), including t…
Stratified wind from a super-Eddington X-ray binary is slower than expected
XRISM collaboration, Marc Audard, Hisamitsu Awaki +132
Accretion discs in strong gravity ubiquitously produce winds, seen as blueshifted absorption lines in the X-ray band of both stellar mass X-ray binaries (black holes and neutron st…
XRISM/Resolve View of Abell 2319: Turbulence, Sloshing, and ICM Dynamics
XRISM Collaboration, Marc Audard, Hisamitsu Awaki +132
We present results from XRISM/Resolve observations of the core of the galaxy cluster Abell 2319, focusing on its kinematic properties. The intracluster medium (ICM) exhibits temper…
Disentangling Multiple Gas Kinematic Drivers in the Perseus Galaxy Cluster
XRISM Collaboration, Marc Audard, Hisamitsu Awaki +143
Galaxy clusters, the Universe's largest halo structures, are filled with 10-100 million degree X-ray-emitting gas. Their evolution is shaped by energetic processes such as feedback…
Structured ionized winds shooting out from a quasar at relativistic speeds
XRISM collaboration
Evidence indicates that supermassive black holes exist at the centers of most galaxies. Their mass correlates with the galactic bulge mass, suggesting a co-evolution with their hos…
XRISM forecast for the Coma cluster: stormy, with a steep power spectrum
XRISM Collaboration, Marc Audard, Hisamitsu Awaki +142
The XRISM Resolve microcalorimeter array measured the velocities of hot intracluster gas at two positions in the Coma galaxy cluster: 3'x3' squares at the center and at 6' (170 kpc…
The bulk motion of gas in the core of the Centaurus galaxy cluster
XRISM collaboration
Galaxy clusters, the largest gravitationally bound structures in the Universe, contain vast amounts of dark matter, galaxies, and hot ionised gas known as the intracluster medium (…
Overionized plasma in the supernova remnant Sagittarius A East anchored by XRISM observations
XRISM Collaboration
Sagittarius A East is a supernova remnant with a unique surrounding environment, as it is located in the immediate vicinity of the supermassive black hole at the Galactic center, S…
The XRISM/Resolve view of the Fe K region of Cyg X-3
XRISM Collaboration
The X-ray binary system Cygnus X-3 (4U 2030+40, V1521 Cyg) is luminous but enigmatic owing to the high intervening absorption. High-resolution X-ray spectroscopy uniquely probes th…
Detection of polarized gamma-ray emission from the Crab nebula with Hitomi Soft Gamma-ray Detector
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +191
We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrom…
Hitomi X-ray Observation of the Pulsar Wind Nebula G21.50.9
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +194
We present results from the Hitomi X-ray observation of a young composite-type supernova remnant (SNR) G21.50.9, whose emission is dominated by the pulsar wind nebula (PWN) cont…
Temperature Structure in the Perseus Cluster Core Observed with Hitomi
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +192
The present paper investigates the temperature structure of the X-ray emitting plasma in the core of the Perseus cluster using the 1.8--20.0 keV data obtained with the Soft X-ray S…
Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +192
The Hitomi SXS spectrum of the Perseus cluster, with 5 eV resolution in the 2-9 keV band, offers an unprecedented benchmark of the atomic modeling and database for hot collis…
Hitomi Observations of the LMC SNR N132D: Highly Redshifted X-ray Emission from Iron Ejecta
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +191
We present Hitomi observations of N132D, a young, X-ray bright, O-rich core-collapse supernova remnant in the Large Magellanic Cloud (LMC). Despite a very short observation of only…
Glimpse of the highly obscured HMXB IGR J16318-4848 with Hitomi
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +191
We report a Hitomi observation of IGR J16318-4848, a high-mass X-ray binary system with an extremely strong absorption of N_H~10^{24} cm^{-2}. Previous X-ray studies revealed that…
Hitomi Observation of Radio Galaxy NGC 1275: The First X-ray Microcalorimeter Spectroscopy of Fe-Kα Line Emission from an Active Galactic Nucleus
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +191
The origin of the narrow Fe-Kα fluorescence line at 6.4 keV from active galactic nuclei has long been under debate; some of the possible sites are the outer accretion disk, the bro…
Atmospheric gas dynamics in the Perseus cluster observed with Hitomi
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +195
Extending the earlier measurements reported in Hitomi collaboration (2016, Nature, 535, 117), we examine the atmospheric gas motions within the central 100~kpc of the Perseus clust…
Measurements of resonant scattering in the Perseus cluster core with Hitomi SXS
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +192
Thanks to its high spectral resolution (~5 eV at 6 keV), the Soft X-ray Spectrometer (SXS) on board Hitomi enables us to measure the detailed structure of spatially resolved emissi…
Hitomi X-ray studies of Giant Radio Pulses from the Crab pulsar
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +201
To search for giant X-ray pulses correlated with the giant radio pulses (GRPs) from the Crab pulsar, we performed a simultaneous observation of the Crab pulsar with the X-ray satel…
Search for Thermal X-ray Features from the Crab nebula with Hitomi Soft X-ray Spectrometer
Hitomi Collaboration, Felix Aharonian, Hiroki Akamatsu +192
The Crab nebula originated from a core-collapse supernova (SN) explosion observed in 1054 A.D. When viewed as a supernova remnant (SNR), it has an anomalously low observed ejecta m…
Hitomi constraints on the 3.5 keV line in the Perseus galaxy cluster
Hitomi Collaboration, Felix A. Aharonian, Hiroki Akamatsu +215
High-resolution X-ray spectroscopy with Hitomi was expected to resolve the origin of the faint unidentified E=3.5 keV emission line reported in several low-resolution studies of va…