512 citations · 6.9k across the 194 of their papers we have counts for
195 papers
Charge Response Simulation of Liquid Argon Compton Cameras for Precise MeV Gamma-Ray Event Reconstruction
Shota Arai, Hirokazu Odaka, Satoshi Takashima +5
We studied the detector response for a liquid-argon time-projection chamber (LArTPC) Compton camera targeting MeV gamma-ray astronomy by a Geant4-based Monte Carlo simulation. The…
The Geometry of Ultra-Fast Outflows Probed by Soft X-ray Variability in PDS 456
Riki Sato, Kouichi Hagino, Toshiya Iwata +20
Constraining the location and geometry of ultra-fast outflows (UFOs) is essential for identifying where they are launched and how they are accelerated. We investigate the soft X-ra…
The Complete Catalog of Gamma-Ray Transients Observed by GRBAlpha & VZLUSAT-2 CubeSat Missions
Marianna Dafcikova, Jakub Ripa, Andras Pal +45
We present the largest sample of gamma-ray transients observed by any CubeSat mission so far. Observations were acquired by a 1U CubeSat GRBAlpha, the smallest astrophysical space…
Chemical enrichment of the Perseus cluster core seen by XRISM/Resolve
XRISM Collaboration, Marc Audard, Hisamitsu Awaki +143
The intracluster medium (ICM) is rich in chemical elements, produced by core-collapse (SNcc) and Type Ia supernovae (SNIa) over the last 12 Gyr. Whereas cluster outskirts are…
Low-Noise SiPM Light Readout and ASIC-Based Charge Readout of a Liquid Argon Time Projection Chamber for MeV Gamma-Ray Measurements
Satoshi Takashima, Hirokazu Odaka, Shota Arai +25
We have developed a compact liquid argon time projection chamber (LArTPC), NanoGRAMS, as a technology demonstrator for the Gamma-Ray and AntiMatter Survey (GRAMS). LArTPCs have the…
Long-term performance of SiPMs in space environment measured by GRBAlpha, GRBBeta, and VZLUSAT-2 CubeSats
Jakub Ripa, Filip Munz, Marianna Dafcikova +46
In this work, we report the successful application of silicon photomultipliers (SiPMs) in gamma-ray burst (GRB) detectors used in CubeSats operating in the low Earth orbit (LEO) ra…
The line modulations of H-like Fe, Ca, Ar, and S observed with /Resolve in Cyg X-3
Tomohiro Hakamata, Hirokazu Odaka, Ryota Tomaru +13
Cygnus X-3, hosting a Wolf-Rayet (WR) star whose dense wind produces various spectral lines due to photoionization by X-rays from a compact object, provides an ideal laboratory for…
A XRISM Study of Highly Ionized Iron Emission Lines from the Low-Eddington-ratio AGN in NGC 7213
Kaito Murakami, Taiki Kawamuro, Ryota Tomaru +10
We present an analysis of XRISM and NuSTAR data obtained for the nearby low-Eddington active galactic nucleus NGC 7213. Our goal is to examine whether its He-like and H-like iron e…
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…
A Fast, Hot Wind from a Nuclear Starburst
XRISM Collaboration, Marc Audard, Hisamitsu Awaki +137
Galaxies with intense star formation often host multiphase, galaxy-scale winds powered by supernovae and fast stellar winds. These are strong enough to disrupt the star-forming int…
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…
In-orbit Demonstration of X-ray Pulsar Navigation with NinjaSat
Naoyuki Ota, Takuya Takahashi, Toru Tamagawa +26
This study demonstrated the pulsar navigation capability of the CubeSat X-ray observatory NinjaSat, which is equipped with two Gas Multiplier Counters (GMCs). The GMCs are sensitiv…
Unification Model of Active Galactic Nuclei by Photoionization Equilibrium Calculation Based on Radiative Hydrodynamic Simulations
Atsushi Tanimoto, Keiichi Wada, Yuki Kudoh +3
To investigate the origin of the dependence of the covering factor on the Eddington ratio suggested by X-ray observations, we examined the angular distribution of HI and HII based…
GRBAlpha, VZLUSAT-2 and GRBBeta -- GRB observations with CubeSats
Jakub Ripa, Marianna Dafcikova, Andras Pal +49
Results from GRBAlpha, VZLUSAT-2 and GRBBeta CubeSats and their on-board gamma-ray detectors for monitoring transients are summarised in this article. GRBAlpha was a 1U CubeSat lau…
Possible time-variable iron-K emission in the circumnuclear region of the Circinus galaxy
Aiko Miyamoto, Taiki Kawamuro, Hirokazu Odaka +2
We present imaging and spatially resolved spectral analyses of eight Chandra data taken for the Circinus galaxy in 22 years to reveal neutral iron-K emission on a circ…
X-ray Analysis and Photon-transport Simulations of SMC X-1: A Warped-disc Origin of the Superorbital Modulation
Satoshi Takashima, Hirokazu Odaka, Ryota Tomaru +3
The luminous accreting pulsar SMC X-1 is an appropriate target to explore the accretion dynamics. SMC X-1 shows unique quasi-periodic flux variability of 40-65days known as sup…
A XRISM/Resolve view of the dynamics in the hot gaseous atmosphere of M87
XRISM Collaboration, M. Audard, H. Awaki +138
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…
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…
Pile-up simulator for XRISM/Xtend onboard the X-ray Imaging and Spectroscopy Mission (XRISM)
Tomokage Yoneyama, Tsubasa Tamba, Hirokazu Odaka +6
In X-ray astronomy, most observatories utilize multi-pixel photon-counting devices. When a photon counting device observes a bright source, we face an unavoidable problem called pi…
XRISM/Resolve reveals the complex iron structure of NGC 7213: Evidence for radial stratification between inner disk and broad-line region
E. Kammoun, T. Kawamuro, K. Murakami +48
We present the first high-resolution X-ray spectrum of NGC 7213 obtained with XRISM/Resolve, supported by simultaneous XMM-Newton, NuSTAR, and SOAR optical data. The XRISM spectrum…
Emission and Absorption Features of Magnetically Driven Disk Winds in Black Hole X-Ray Binaries
Atsushi Tanimoto, Keigo Fukumura, Shoji Ogawa +5
We investigate accretion disk winds commonly observed in galactic black hole (BH) X-ray binaries (XRB), which manifest as blueshifted absorption features in X-ray spectra. We model…
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…
Comparing XRISM cluster velocity dispersions with predictions from cosmological simulations: are feedback models too ejective?
XRISM Collaboration, Marc Audard, Hisamitsu Awaki +147
The dynamics of the intra-cluster medium (ICM), the hot plasma that fills galaxy clusters, are shaped by gravity-driven cluster mergers and feedback from supermassive black holes (…
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…