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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…
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…
Possible Supercritical Accretion on the ULX in the Metal-poor Galaxy IZw18
Marina Yoshimoto, Tomokage Yoneyama, Hirofumi Noda +2
We present an analysis of X-ray observations of the Ultraluminous X-ray source (ULX) in IZw18 based on archival data taken with Chandra, XMM-Newton, and Suzaku. This ULX is conside…
Decomposing the Spectrum of Ultra-Luminous X-ray Pulsar NGC 300 ULX-1
Shogo B. Kobayashi, Hirofumi Noda, Teruaki Enoto +3
A phase-resolved analysis on the X-ray spectrum of Ultra-Luminous X-ray Pulsar (ULXP) NGC 300 ULX-1 is performed with data taken with XMM-Newton and NuSTAR on 2016 December 16th. I…
A broadband X-ray imaging spectroscopy in the 2030s: the FORCE mission
Koji Mori, Takeshi G. Tsuru, Kazuhiro Nakazawa +49
In this multi-messenger astronomy era, all the observational probes are improving their sensitivities and overall performance. The Focusing on Relativistic universe and Cosmic Evol…
Narrow Fe-K Reverberation Mapping Unveils the Deactivated Broad-Line Region in a Changing-Look Active Galactic Nucleus
Hirofumi Noda, Taisei Mineta, Takeo Minezaki +11
"Changing-look active galactic nuclei" (CLAGNs) are known to change their apparent types between types 1 and 2, usually accompanied by a drastic change in their luminosity on times…
Magnetic Reconnection in Black-Hole Magnetospheres: Lepton Loading into Jets, Superluminal Radio Blobs, and Multi-wavelength Flares
Shigeo S. Kimura, Kenji Toma, Hirofumi Noda +1
Supermassive black holes in active galactic nuclei launch relativistic jets, as indicated by observed superluminal radio blobs. The energy source of these jets is widely discussed…
Probing the circumnuclear environment of NGC1275 with High-Resolution X-ray spectroscopy
Christopher S. Reynolds, Robyn N. Smith, Andrew C. Fabian +6
NGC1275 is the Brightest Cluster Galaxy (BCG) in the Perseus cluster and hosts the active galactic nucleus (AGN) that is heating the central 100\,kpc of the intracluster medium (IC…
Discovery of a transient X-ray source Suzaku J1305-4930 in NGC 4945
Shuntaro Ide, Kiyoshi Hayashida, Hirofumi Noda +3
We report the serendipitous discovery of a transient X-ray source, Suzaku J13054930, 3 kpc southwest of the nucleus of the Seyfert 2 galaxy NGC 4945. Among the seven Suzak…
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…
Constraints on the Chemical Enrichment History of the Perseus Cluster of Galaxies from High-Resolution X-ray Spectroscopy
A. Simionescu, S. Nakashima, H. Yamaguchi +32
High-resolution spectroscopy of the core of the Perseus Cluster of galaxies, using the satellite above 2 keV and the - Reflection Grating Spectrometer at lowe…
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…
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…
Fe-K Line Time variability and Ni abundance of Distant Reflector in Seyfert Galaxies
Yasushi Fukazawa, Shun'ya Furui, Kazuma Hayashi +3
We have performed systematic studies of narrow Fe-K line (6.4 keV) flux variability and Ni-K line intensity for Seyfert galaxies, using {\em Suzaku} and {\em XMM-Newton} archival d…