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823 results on '"Sawada, Makoto"'

1. Probing Shocked Ejecta in SN 1987A with XRISM-Resolve: the effects of the gate valve closed

Author

Sapienza, Vincenzo, Miceli, Marco, Bamba, Aya, Orlando, Salvatore, Lee, Shiu-Hang, Nagataki, Shigehiro, Ono, Masaomi, Katsuda, Satoru, Mori, Koji, Sawada, Makoto, Terada, Yukikatsu, Giuffrida, Roberta, and Bocchino, Fabrizio

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Supernova (SN) 1987A is widely regarded as an excellent candidate for leveraging the capabilities of the freshly launched XRISM satellite. Recent researches indicate that the X-ray emission from SN 1987A will increasingly originate from its ejecta in the years to come. In a previous study, we thoroughly examined the proficiency of XRISM-Resolve in identifying signatures of shocked ejecta in SN 1987A, synthesizing the XRISM-Resolve spectrum based on a state-of-the-art magneto-hydrodynamic simulation. However, following the satellite's launch, a technical issue arose with the XRISM instrument's gate valve, which failed to open, thereby affecting observations with the Resolve spectrometer. Here, we update our analysis, reevaluating our diagnostic approach under the assumption that the gate valve remains closed. We find that, even with the reduced instrumental capabilities, it will be possible to pinpoint the ejecta contribution through the study of the line profiles in the XRISM-Resolve spectrum of SN 1987A., Comment: 4 pages, 1 figure. Updates of the results described in Sapienza et al. 2024 (http://doi.org/10.3847/2041-8213/ad16e3). Submitted for publication in Research Notes of the AAS

Published
2024

2. Is the low-energy tail of shock-accelerated protons responsible for over-ionized plasma in supernova remnants?

Author

Sawada, Makoto, Gu, Liyi, and Yamazaki, Ryo

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Over-ionized, recombining plasma is an emerging class of X-ray bright supernova remnants (SNRs). This unique thermal state where the ionization temperature ($T_{\rm z}$) is significantly higher than the electron temperature ($T_{\rm e}$) is not expected from the standard evolution model assuming a point explosion in a uniform interstellar medium, requiring a new scenario for the dynamical and thermal evolution. A recently proposed idea attributes the over-ionization state to additional ionization contribution from the low-energy tail of shock-accelerated protons. However, this new scenario has been left untested, especially from the atomic physics point of view. We report calculation results of the proton impact ionization rates of heavy-element ions in ejecta of SNRs. We conservatively estimate the requirement for accelerated protons, and find that their relative number density to thermal electrons needs to be higher than $5~(T_{\rm e}/{\rm 1~keV})\%$ in order to explain the observed over-ionization degree at $T_{\rm z}/T_{\rm e} \ge 2$ for K-shell emission. We conclude that the proton ionization scenario is not feasible because such a high abundance of accelerated protons is prohibited by the injection fraction from thermal to non-thermal energies, which is expected to be $\sim 1\%$ at largest., Comment: 16 pages, 10 figures, submitted to PASJ

Published
2024

3. Missing Titanium in the Asymmetric Supernova Remnant W49B

Author

Sato, Toshiki, Sawada, Makoto, Maeda, Keiichi, Hughes, John P., and Williams, Brian J.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The progenitor of the W49B supernova remnant is still under debate. One of the candidates is a jet-driven core-collapse supernova. In such a highly asymmetric explosion, a strong $\alpha$-rich freezeout is expected in local high entropy regions, which should enrich elements synthesized by the capture of $\alpha$-particles such as $^{44}$Ti and $^{48}$Cr (decaying to $^{44}$Ca and $^{48}$Ti, respectively). In the present work, in order to infer the progenitor of the W49B remnant, we constrain the amount of stable Ti ($^{48}$Ti) synthesized, using the {\it Suzaku} observation. We found no firm evidence for the Ti line and set the upper limit of $M_{\rm Ti}/M_{\rm Fe} < 8.2 \times$ 10$^{-4}$ (99\% limit using Xspec) and $M_{\rm Ti}/M_{\rm Fe} < 1.9 \times$ 10$^{-3}$ (99\% limit using SPEX), and thus excluded almost all hypernova/jet-driven supernova models. Our results, as complemented by some previous studies, suggest that a Type Ia supernova from a near-$M_{\rm Ch}$ (Chandrasekhar mass) white dwarf is the most favorable candidate for the origin of W49B. Future observations with X-ray calorimeter missions, such as XRISM, will give us a stronger constraint on the progenitor., Comment: Submitted to ApJ, 7 pages, 3 figures, 1 table

Published
2024

4. Photosensitizer-singlet oxygen sensor conjugated silica nanoparticles for photodynamic therapy and bioimaging.

Author

Sobhanan, Jeladhara, Ono, Kenji, Okamoto, Takuya, Sawada, Makoto, Weiss, Paul, and Biju, Vasudevanpillai

Abstract

Intracellular singlet oxygen (1O2) generation and detection help optimize the outcome of photodynamic therapy (PDT). Theranostics programmed for on-demand phototriggered 1O2 release and bioimaging have great potential to transform PDT. We demonstrate an ultrasensitive fluorescence turn-on sensor-sensitizer-RGD peptide-silica nanoarchitecture and its 1O2 generation-releasing-storing-sensing properties at the single-particle level or in living cells. The sensor and sensitizer in the nanoarchitecture are an aminomethyl anthracene (AMA)-coumarin dyad and a porphyrin or CdSe/ZnS quantum dots (QDs), respectively. The AMA in the dyad quantitatively quenches the fluorescence of coumarin by intramolecular electron transfer, the porphyrin or QD moiety generates 1O2, and the RGD peptide facilitates intracellular delivery. The small size, below 200 nm, as verified by scanning electron microscopy and differential light scattering measurements, of the architecture within the 1O2 diffusion length enables fast and efficient intracellular fluorescence switching by the tandem ultraviolet (UV)-visible or visible-near-infrared (NIR) photo-triggering. While the red emission and 1O2 generation by the porphyrin are continually turned on, the blue emission of coumarin is uncaged into 230-fold intensity enhancement by on-demand photo-triggering. The 1O2 production and release by the nanoarchitecture enable spectro-temporally controlled cell imaging and apoptotic cell death; the latter is verified from cytotoxic data under dark and phototriggering conditions. Furthermore, the bioimaging potential of the TCPP-based nanoarchitecture is examined in vivo in B6 mice.

Published
2024

5. High count rate effects in event processing for XRISM/Resolve x-ray microcalorimeter

Author

Mizumoto, Misaki, Tsujimoto, Masahiro, Cumbee, Renata S., Eckart, Megan E., Ishisaki, Yoshitaka, Kilbourne, Caroline A., Hodges-Kluck, Edmund, Leutenegger, Maurice A., Porter, Frederick S., Sawada, Makoto, Takei, Yoh, Uchida, Yuusuke, Yamada, Shin'ya, and team, the XRISM Resolve

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The spectroscopic performance of x-ray instruments can be affected at high count rates. The effects and mitigation in the optical chain, such as x-ray attenuation filters or de-focusing mirrors, are widely discussed, but those in the signal chain are not. Using the Resolve x-ray microcalorimeter onboard the XRISM satellite, we discuss the effects observed during high count rate measurements and how these can be modeled. We focus on three instrumental effects that impact performance at high count rate: CPU limit, pile up, and electrical cross talk. High count rate data were obtained during ground testing using the flight model instrument and a calibration x-ray source. A simulated observation of GX 13+1 is presented to illustrate how to estimate these effects based on these models for observation planning. The impact of these effects on high count rate observations is discussed., Comment: 16 pages, 20 figures, Proc. SPIE

Published
2023
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6. Probing Shocked Ejecta in SN 1987A: A novel diagnostic approach using XRISM-Resolve

Author

Sapienza, Vincenzo, Miceli, Marco, Bamba, Aya, Orlando, Salvatore, Lee, Shiu-Hang, Nagataki, Shigehiro, Ono, Masaomi, Katsuda, Satoru, Mori, Koji, Sawada, Makoto, Terada, Yukikatsu, Giuffrida, Roberta, and Bocchino, Fabrizio

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Supernova (SN) 1987A is one of the best candidates to exploit the capabilities of the freshly launched XRISM satellite. This celestial object offers the unique opportunity to study the evolution of a SN into a young supernova remnant. To date, the X-ray emission has been dominated by the shocked circumstellar medium (CSM), with no shocked ejecta firmly detected. However, recent studies provide compelling evidence that in the forthcoming years the X-ray emission from SN 1987A will increasingly stem from the ejecta. Our aim is to assess the proficiency of XRISM-Resolve high resolution spectrometer in pinpointing signatures of the shocked ejecta in SN 1987A. Taking advantage of a self consistent state-of-art magneto-hydrodynamic simulation that describes the evolution from SN 1987A to its remnant, we synthesized the XRISM-Resolve spectrum of SN 1987A, as it would be collected in the allocated observation during the performance verification phase, which is foreseen for 2024. Our predictions clearly show the leading role of shocked ejecta in shaping the profile of the emission lines. The Doppler broadening associated with the bulk motion along the line of sight of the rapidly expanding ejecta is shown to increase the line widths well above the values observed so far. The quantitative comparison between our synthetic spectra and the XRISM spectra will enable us to establish a strong connection between the broadened line emission and the freshly shocked ejecta. This, in turn, will allow us to retrieve the ejecta dynamics and chemical composition from the X-ray emission., Comment: 9 pages, 4 figures, 1 table, Accepted for publication in The Astrophysical Journal Letters

Published
2023

7. X-ray spectra of the Fe-L complex III: systematic uncertainties in the atomic data

Author

Gu, Liyi, Shah, Chintan, Mao, Junjie, Raassen, A. J. J., de Plaa, Jelle, Pinto, Ciro, Akamatsu, Hiroki, Werner, Norbert, Simionescu, Aurora, Mernier, Francois, Sawada, Makoto, Mohanty, Pranav, Amaro, Pedro, Gu, Ming Feng, Porter, F. Scott, Lopez-Urrutia, Jose R. Crespo, and Kaastra, Jelle S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Physics - Atomic Physics
Abstract

There has been a growing request from the X-ray astronomy community for a quantitative estimate of systematic uncertainties originating from the atomic data used in plasma codes. Though there have been several studies looking into atomic data uncertainties using theoretical calculations, in general, there is no commonly accepted solution for this task. We present a new approach for estimating uncertainties in the line emissivities for the current models of collisional plasma, mainly based upon dedicated analysis of observed high resolution spectra of stellar coronae and galaxy clusters. We find that the systematic uncertainties of the observed lines consistently show anti-correlation with the model line fluxes, after properly accounting for the additional uncertainties from the ion concentration calculation. The strong lines in the spectra are in general better reproduced, indicating that the atomic data and modeling of the main transitions are more accurate than those for the minor ones. This underlying anti-correlation is found to be roughly independent on source properties, line positions, ion species, and the line formation processes. We further apply our method to the simulated XRISM and Athena observations of collisional plasma sources and discuss the impact of uncertainties on the interpretation of these spectra. The typical uncertainties are 1-2% on temperature and 3-20% on abundances of O, Ne, Fe, Mg, and Ni., Comment: 18 pages, 18 figures, accepted for publication in Astronomy & Astrophysics

Published
2022
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9. Detailed Design of the Science Operations for the XRISM mission

Author

Terada, Yukikatsu, Holland, Matt, Loewenstein, Michael, Tashiro, Makoto, Takahashi, Hiromitsu, Nobukawa, Masayoshi, Mizuno, Tsunefumi, Tamura, Takayuki, Uno, Shin'ichiro, Watanabe, Shin, Baluta, Chris, Burns, Laura, Ebisawa, Ken, Eguchi, Satoshi, Fukazawa, Yasushi, Hayashi, Katsuhiro, Iizuka, Ryo, Katsuda, Satoru, Kitaguchi, Takao, Kubota, Aya, Miller, Eric, Mukai, Koji, Nakashima, Shinya, Nakazawa, Kazuhiro, Odaka, Hirokazu, Ohno, Masanori, Ota, Naomi, Sato, Rie, Sawada, Makoto, Sugawara, Yasuharu, Shidatsu, Megumi, Tamba, Tsubasa, Tanimoto, Atsushi, Terashima, Yuichi, Tsuboi, Yohko, Uchida, Yuusuke, Uchiyama, Hideki, Yamauchi, Shigeo, and Yaqoob, Tahir

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

XRISM is an X-ray astronomical mission by the JAXA, NASA, ESA and other international participants, that is planned for launch in 2022 (Japanese fiscal year), to quickly restore high-resolution X-ray spectroscopy of astrophysical objects. To enhance the scientific outputs of the mission, the Science Operations Team (SOT) is structured independently from the instrument teams and the Mission Operations Team. The responsibilities of the SOT are divided into four categories: 1) guest observer program and data distributions, 2) distribution of analysis software and the calibration database, 3) guest observer support activities, and 4) performance verification and optimization activities. As the first step, lessons on the science operations learned from past Japanese X-ray missions are reviewed, and 15 kinds of lessons are identified. Among them, a) the importance of early preparation of the operations from the ground stage, b) construction of an independent team for science operations separate from the instrument development, and c) operations with well-defined duties by appointed members are recognized as key lessons. Then, the team structure and the task division between the mission and science operations are defined; the tasks are shared among Japan, US, and Europe and are performed by three centers, the SOC, SDC, and ESAC, respectively. The SOC is designed to perform tasks close to the spacecraft operations, such as spacecraft planning, quick-look health checks, pre-pipeline processing, etc., and the SDC covers tasks regarding data calibration processing, maintenance of analysis tools, etc. The data-archive and user-support activities are covered both by the SOC and SDC. Finally, the science-operations tasks and tools are defined and prepared before launch., Comment: 42 pages, 7 figures, 8 table, Accepted for Publication in JATIS (SPIE)

Published
2021
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11. X-ray spectra of the Fe-L complex II: atomic data constraints from EBIT experiment and X-ray grating observations of Capella

Author

Gu, Liyi, Shah, Chintan, Mao, Junjie, Raassen, A. J. J., de Plaa, Jelle, Pinto, Ciro, Akamatsu, Hiroki, Werner, Norbert, Simionescu, Aurora, Mernier, François, Sawada, Makoto, Mohanty, Pranav, Amaro, Pedro, Gu, Ming Feng, Porter, F. Scott, López-Urrutia, José R. Crespo, and Kaastra, Jelle S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Atomic Physics
Abstract

The Hitomi results for the Perseus cluster have shown that accurate atomic models are essential to the success of X-ray spectroscopic missions, and just as important as knowledge on instrumental calibration and astrophysical modeling. Preparing the models requires a multifaceted approach, including theoretical calculations, laboratory measurements, and calibration using real observations. In a previous paper, we presented a calculation of the electron impact cross sections on the transitions forming the Fe-L complex. In the present work, we systematically test the calculation against cross sections of ions measured in an electron beam ion trap experiment. A two-dimensional analysis in the electron beam energies and X-ray photon energies is utilized to disentangle radiative channels following dielectronic recombination, direct electron-impact excitation, and resonant excitation processes in the experimental data. The data calibrated through laboratory measurements are further fed into global modeling of the Chandra grating spectrum of Capella. We investigate and compare the fit quality, as well as sensitivity of the derived physical parameters to the underlying atomic data and the astrophysical plasma modeling. We further list the potential areas of disagreement between the observation and the present calculations, which in turn calls for renewed efforts in theoretical calculations and targeted laboratory measurements., Comment: Accepted for publication in A&A

Published
2020
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12. Unlocking the Capabilities of Future High-Resolution X-ray Spectroscopy Missions Through Laboratory Astrophysics

Author

Betancourt-Martinez, Gabriele, Akamatsu, Hiroki, Barret, Didier, Bautista, Manuel, Bernitt, Sven, Bianchi, Stefano, Bodewits, Dennis, Brickhouse, Nancy, Brown, Gregory V., Costantini, Elisa, Coreno, Marcello, López-Urrutia, José R. Crespo, Cumbee, Renata, Eckart, Megan, Ferland, Gary, Fiore, Fabrizio, Fogle, Michael, Foster, Adam, Garcia, Javier, Gorczyca, Tom, Grinberg, Victoria, Grosso, Nicolas, Gu, Liyi, Gu, Ming Feng, Guainazzi, Matteo, Hell, Natalie, Herder, Jan-Willem den, Kaastra, Jelle, Kallman, Timothy, Lee, Julia, Leutenegger, Maurice, Marler, Joan, McCammon, Dan, Nakashima, Shinya, Nicastro, Fabrizio, Paerels, Frits, Pajot, François, Pointecouteau, Etienne, Porquet, Delphine, Porter, F. Scott, Savin, Daniel Wolf, Sawada, Makoto, Shah, Chintan, Simionescu, Aurora, de Simone, Monica, Sosolik, Chad, Stancil, Phillip, Steinbrügge, René, and Yamaguchi, Hiroya

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

Thanks to high-resolution and non-dispersive spectrometers onboard future X-ray missions such as XRISM and Athena, we are finally poised to answer important questions about the formation and evolution of galaxies and large-scale structure. However, we currently lack an adequate understanding of many atomic processes behind the spectral features we will soon observe. Large error bars on parameters as critical as transition energies and atomic cross sections can lead to unacceptable uncertainties in the calculations of e.g., elemental abundance, velocity, and temperature. Unless we address these issues, we risk limiting the full scientific potential of these missions. Laboratory astrophysics, which comprises theoretical and experimental studies of the underlying physics behind observable astrophysical processes, is therefore central to the success of these missions., Comment: Science white paper submitted to the Astro2020 Decadal Survey

Published
2019

13. Ionization age of iron ejecta in the Galactic Type Ia supernova remnant G306.3-0.9

Author

Sawada, Makoto, Tachibana, Katsuhiro, Uchida, Hiroyuki, Ito, Yuta, Matsumura, Hideaki, Bamba, Aya, Tsuru, Takeshi Go, and Tanaka, Takaaki

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present a 190 ks observation of the Galactic supernova remnant (SNR) G306.3-0.9 with Suzaku. To study ejecta properties of this possible Type Ia SNR, the absolute energy scale at the Fe-K band was calibrated to a level of uncertainty less than 10 eV by a cross-calibration with the Hitomi microcalorimeter using the Perseus cluster spectra. This enabled us for the first time to accurately determine the ionization state of the Fe K$\alpha$ line of this SNR. The ionization timescale ($\tau$) of the Fe ejecta was measured to be $\log_{10} \tau$ (cm$^{-3}$ s) $=10.24\pm0.03$, significantly smaller than previous measurements. Marginally detected K$\alpha$ lines of Cr and Mn have consistent ionization timescales with Fe. The global spectrum was well fitted with shocked interstellar matter (ISM) and at least two ejecta components with different ionization timescales for Fe and intermediate mass elements (IME) such as S and Ar. One plausible interpretation of the one-order-of-magnitude shorter timescale of Fe than that of IME ($\log_{10} \tau = 11.17\pm0.07$) is a chemically stratified structure of ejecta. By comparing the X-ray absorption column to the HI distribution decomposed along the line of sight, we refined the distance to be $\sim$20 kpc. The large ISM-to-ejecta shocked mass ratio of $\sim$100 and dynamical timescale of $\sim$6 kyr place the SNR in the late Sedov phase. These properties are consistent with a stratified ejecta structure that has survived the mixing processes expected in an evolved supernova remnant., Comment: 16 pages, 10 figures, 3 tables. Accepted for publication in PASJ

Published
2019
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14. Detection of polarized gamma-ray emission from the Crab nebula with Hitomi Soft Gamma-ray Detector

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Iwai, Masachika, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier, Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stephane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Schartel, Norbert, Serlemtsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Lukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shin'ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shin'ichiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, Zoghbi, Abderahmen, and Uchida, Yuusuke

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

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 spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray / gamma-ray sources on the sky, and, the only source from which polarized X-ray photons have been detected. SGD observed the Crab nebula during the initial test observation phase of Hitomi. We performed the data analysis of the SGD observation, the SGD background estimation and the SGD Monte Carlo simulations, and, successfully detected polarized gamma-ray emission from the Crab nebula with only about 5 ks exposure time. The obtained polarization fraction of the phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1 $\pm$ 10.6)% and, the polarization angle is 110.7$^o$ + 13.2 / $-$13.0$^o$ in the energy range of 60--160 keV (The errors correspond to the 1 sigma deviation). The confidence level of the polarization detection was 99.3%. The polarization angle measured by SGD is about one sigma deviation with the projected spin axis of the pulsar, 124.0$^o$ $\pm$0.1$^o$., Comment: 19 pages, 18 figures, 6 tables. Accepted for publication in PASJ

Published
2018
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15. Discovery of recombining plasma from the faintest GeV SNR HB 21 and a possible scenario of the cosmic ray escaping from SNR shocks

Author

Suzuki, Hiromasa, Bamba, Aya, Nakazawa, Kazuhiro, Furuta, Yoshihiro, Sawada, Makoto, Yamazaki, Ryo, and Koyama, Katsuji

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present an X-ray study of the GeV gamma-ray supernova remnant (SNR) HB 21 with Suzaku. HB 21 is interacting with molecular clouds and the faintest in the GeV band among known GeV SNRs. We discovered strong radiative recombination continua of Si and S from the center of the remnant, which provide the direct evidence of a recombining plasma (RP). The total emission can be explained with the RP and ionizing plasma components. The electron temperature and recombination timescale of the RP component were estimated as 0.17 (0.15-0.18) keV and 3.2 (2.0-4.8) $\times$ 10$^{11}$ s cm$^{-3}$, respectively. The estimated age of the RP (RP age; $\sim$ 170 kyr) is the longest among known recombining GeV SNRs, because of very low density of electrons ($\sim$ 0.05 cm$^{-3}$). We have examined dependencies of GeV spectral indices on each of RP ages and SNR diameters for nine recombining GeV SNRs. Both showed possible positive correlations, indicating that both the parameters can be good indicators of properties of accelerated protons, for instance, degree of escape from the SNR shocks. A possible scenario for a process of proton escape is introduced; interaction with molecular clouds makes weaker magnetic turbulence and cosmic-ray protons escape, simultaneously cooling down the thermal electrons and generate an RP., Comment: 10 pages, 6 figures, accepted for Publications of the Astronomical Society of Japan

Published
2018
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16. Hitomi X-ray Observation of the Pulsar Wind Nebula G21.5$-$0.9

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Iwai, Masachika, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier, Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stéphane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sato, Toshiki, Sawada, Makoto, Schartel, Norbert, Serlemtsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Łukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shin'ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shin'ichiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, Zoghbi, Abderahmen, Nakaniwa, Nozomu, Murakami, Hiroaki, and Guest, Benson

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present results from the Hitomi X-ray observation of a young composite-type supernova remnant (SNR) G21.5$-$0.9, whose emission is dominated by the pulsar wind nebula (PWN) contribution. The X-ray spectra in the 0.8-80 keV range obtained with the Soft X-ray Spectrometer (SXS), Soft X-ray Imager (SXI) and Hard X-ray Imager (HXI) show a significant break in the continuum as previously found with the NuSTAR observation. After taking into account all known emissions from the SNR other than the PWN itself, we find that the Hitomi spectra can be fitted with a broken power law with photon indices of $\Gamma_1=1.74\pm0.02$ and $\Gamma_2=2.14\pm0.01$ below and above the break at $7.1\pm0.3$ keV, which is significantly lower than the NuSTAR result ($\sim9.0$ keV). The spectral break cannot be reproduced by time-dependent particle injection one-zone spectral energy distribution models, which strongly indicates that a more complex emission model is needed, as suggested by recent theoretical models. We also search for narrow emission or absorption lines with the SXS, and perform a timing analysis of PSR J1833$-$1034 with the HXI and SGD. No significant pulsation is found from the pulsar. However, unexpectedly, narrow absorption line features are detected in the SXS data at 4.2345 keV and 9.296 keV with a significance of 3.65 $\sigma$. While the origin of these features is not understood, their mere detection opens up a new field of research and was only possible with the high resolution, sensitivity and ability to measure extended sources provided by an X-ray microcalorimeter., Comment: 16 pages, 8 figures, 4 tables. Accepted for publication in PASJ

Published
2018
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17. The Transition from Young to Middle-aged Supernova Remnants: Thermal and Nonthermal Aspects of SNR N132D

Author

Bamba, Aya, Ohira, Yutaka, Yamazaki, Ryo, Sawada, Makoto, Terada, Yukikatsu, Koyama, Katsuji, Miller, Eric D., Yamaguchi, Hiroya, Katsuda, Satoru, Nobukawa, Masayoshi, and Nobukawa, Kumiko K.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Supernova remnants (SNRs) are the primary candidate of Galactic cosmic-ray accelerators. It is still an open issue when and how young SNRs, which typically exhibit strong synchrotron X-rays and GeV and TeV gamma-rays, undergo the state transition to middle-aged SNRs dominated by thermal X-rays and GeV gamma-rays. The SNR N132D in the Large Magellanic Cloud is an ideal target to study such a transition, exhibiting bright X-rays and gamma-rays, and with the expected age of ~2500 yrs. In this paper we present results of NuSTAR and Suzaku spectroscopy. We reveal that N132D has a nearly equilibrium plasma with a temperature of > 5 keV or a recombining plasma with a lower temperature (~1.5 keV) and a recombining timescale (net) of 8.8 (7.0--10.0)e12 cm^-3s. Together with the center filled morphology observed in the iron K line image, our results suggest that N132D is now at transition stage from a young SNR to middle-aged. We have constrained the tight upper-limit of nonthermal X-rays. Bright gamma-rays compared to faint nonthermal X-rays suggest that the gamma-rays are hadronic in origin. The spectral energy distribution from radio to gamma-rays shows a proton cut-off energy of ~30 TeV. These facts confirm that N132D is in the transition from young to middle-aged SNR. The large thermal energy of > 10^51 erg and accelerated proton energy of ~ 10^50 erg suggest the supernova explosion might have been very energetic., Comment: 11 pages, 13 figures, ApJ, in press

Published
2018
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18. Temperature Structure in the Perseus Cluster Core Observed with Hitomi

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furukawa, Maki, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Iwai, Masachika, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Kato, Yuichi, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier, Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stéphane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Schartel, Norbert, Serlemtsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Łukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shiníchiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shiníchiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, and Zoghbi, Abderahmen

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

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 Spectrometer (SXS) onboard the Hitomi Observatory. A series of four observations were carried out, with a total effective exposure time of 338 ks and covering a central region $\sim7'$ in diameter. The SXS was operated with an energy resolution of $\sim$5 eV (full width at half maximum) at 5.9 keV. Not only fine structures of K-shell lines in He-like ions but also transitions from higher principal quantum numbers are clearly resolved from Si through Fe. This enables us to perform temperature diagnostics using the line ratios of Si, S, Ar, Ca, and Fe, and to provide the first direct measurement of the excitation temperature and ionization temperature in the Perseus cluster. The observed spectrum is roughly reproduced by a single temperature thermal plasma model in collisional ionization equilibrium, but detailed line ratio diagnostics reveal slight deviations from this approximation. In particular, the data exhibit an apparent trend of increasing ionization temperature with increasing atomic mass, as well as small differences between the ionization and excitation temperatures for Fe, the only element for which both temperatures can be measured. The best-fit two-temperature models suggest a combination of 3 and 5 keV gas, which is consistent with the idea that the observed small deviations from a single temperature approximation are due to the effects of projection of the known radial temperature gradient in the cluster core along the line of sight. Comparison with the Chandra/ACIS and the XMM-Newton/RGS results on the other hand suggests that additional lower-temperature components are present in the ICM but not detectable by Hitomi SXS given its 1.8--20 keV energy band., Comment: 29 pages, 19 figures, 9 tables. Accepted for publication in PASJ

Published
2017
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19. Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hell, Natalie, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Iwai, Masachika, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier, Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stéphane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Schartel, Norbert, Serlemtsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Łukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shin'ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shin'ichiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, Zoghbi, Abderahmen, and Raassen, A. J. J.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Hitomi SXS spectrum of the Perseus cluster, with $\sim$5 eV resolution in the 2-9 keV band, offers an unprecedented benchmark of the atomic modeling and database for hot collisional plasmas. It reveals both successes and challenges of the current atomic codes. The latest versions of AtomDB/APEC (3.0.8), SPEX (3.03.00), and CHIANTI (8.0) all provide reasonable fits to the broad-band spectrum, and are in close agreement on best-fit temperature, emission measure, and abundances of a few elements such as Ni. For the Fe abundance, the APEC and SPEX measurements differ by 16%, which is 17 times higher than the statistical uncertainty. This is mostly attributed to the differences in adopted collisional excitation and dielectronic recombination rates of the strongest emission lines. We further investigate and compare the sensitivity of the derived physical parameters to the astrophysical source modeling and instrumental effects. The Hitomi results show that an accurate atomic code is as important as the astrophysical modeling and instrumental calibration aspects. Substantial updates of atomic databases and targeted laboratory measurements are needed to get the current codes ready for the data from the next Hitomi-level mission., Comment: 46 pages, 25 figures, 11 tables. Accepted for publication in PASJ

Published
2017
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20. Hitomi Observations of the LMC SNR N132D: Highly Redshifted X-ray Emission from Iron Ejecta

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Iwai, Masachika, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier, Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stéphane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sato, Toshiki, Sawada, Makoto, Schartel, Norbert, Serlemtsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Łukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shin'ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shin'ichiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, and Zoghbi, Abderahmen

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

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 3.7 ks, the Soft X-ray Spectrometer (SXS) easily detects the line complexes of highly ionized S K and Fe K with 16-17 counts in each. The Fe feature is measured for the first time at high spectral resolution. Based on the plausible assumption that the Fe K emission is dominated by He-like ions, we find that the material responsible for this Fe emission is highly redshifted at ~800 km/s compared to the local LMC interstellar medium (ISM), with a 90% credible interval of 50-1500 km/s if a weakly informative prior is placed on possible line broadening. This indicates (1) that the Fe emission arises from the supernova ejecta, and (2) that these ejecta are highly asymmetric, since no blue-shifted component is found. The S K velocity is consistent with the local LMC ISM, and is likely from swept-up ISM material. These results are consistent with spatial mapping that shows the He-like Fe concentrated in the interior of the remnant and the S tracing the outer shell. The results also show that even with a very small number of counts, direct velocity measurements from Doppler-shifted lines detected in extended objects like supernova remnants are now possible. Thanks to the very low SXS background of ~1 event per spectral resolution element per 100 ks, such results are obtainable during short pointed or slew observations with similar instruments. This highlights the power of high-spectral-resolution imaging observations, and demonstrates the new window that has been opened with Hitomi and will be greatly widened with future missions such as the X-ray Astronomy Recovery Mission (XARM) and Athena., Comment: 18 pages, 15 figures, 1 table. Accepted for publication by PASJ

Published
2017
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21. Glimpse of the highly obscured HMXB IGR J16318-4848 with Hitomi

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Iwai, Masachika, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier O., Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stéphane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Schartel, Norbert, Serlemitsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Łukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shin'ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shin'ichiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, Zoghbi, Abderahmen, and Nakaniwa, Nozomi

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

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 its spectrum is dominated by strong fluorescence lines of Fe as well as continuum emission. For physical and geometrical insight into the nature of the reprocessing material, we utilize the high spectroscopic resolving power of the X-ray microcalorimeter (the soft X-ray spectrometer; SXS) and the wide-band sensitivity by the soft and hard X-ray imager (SXI and HXI) aboard Hitomi. Even though photon counts are limited due to unintended off-axis pointing, the SXS spectrum resolves Fe K{\alpha_1} and K{\alpha_2} lines and puts strong constraints on the line centroid and width. The line width corresponds to the velocity of 160^{+300}_{-70} km s^{-1}. This represents the most accurate, and smallest, width measurement of this line made so far from any X-ray binary, much less than the Doppler broadening and shift expected from speeds which are characteristic of similar systems. Combined with the K-shell edge energy measured by the SXI and HXI spectra, the ionization state of Fe is estimated to be in the range of Fe I--IV. Considering the estimated ionization parameter and the distance between the X-ray source and the absorber, the density and thickness of the materials are estimated. The extraordinarily strong absorption and the absence of a Compton shoulder component is confirmed. These characteristics suggest reprocessing materials which are distributed in a narrow solid angle or scattering primarily with warm free electrons or neutral hydrogen., Comment: 17 pages, 9 figures, 2 tables, accepted for publication in PASJ

Published
2017
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22. Hitomi Observation of Radio Galaxy NGC 1275: The First X-ray Microcalorimeter Spectroscopy of Fe-K{\alpha} Line Emission from an Active Galactic Nucleus

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Iwai, Masachika, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier O., Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stéphane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Schartel, Norbert, Serlemitsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Łukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shin'ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shin'ichiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, Zoghbi, Abderahmen, and Kawamuro, Taiki

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The origin of the narrow Fe-K{\alpha} 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 broad line region, a molecular torus, or interstellar/intracluster media. In February-March 2016, we performed the first X-ray microcalorimeter spectroscopy with the Soft X-ray Spectrometer (SXS) onboard the Hitomi satellite of the Fanaroff-Riley type I radio galaxy NGC 1275 at the center of the Perseus cluster of galaxies. With the high energy resolution of ~5 eV at 6 keV achieved by Hitomi/SXS, we detected the Fe-K{\alpha} line with ~5.4 {\sigma} significance. The velocity width is constrained to be 500-1600 km s$^{-1}$ (FWHM for Gaussian models) at 90% confidence. The SXS also constrains the continuum level from the NGC 1275 nucleus up to ~20 keV, giving an equivalent width ~20 eV of the 6.4 keV line. Because the velocity width is narrower than that of broad H{\alpha} line of ~2750 km s$^{-1}$, we can exclude a large contribution to the line flux from the accretion disk and the broad line region. Furthermore, we performed pixel map analyses on the Hitomi/SXS data and image analyses on the Chandra archival data, and revealed that the Fe-K{\alpha} line comes from a region within ~1.6 kpc from the NGC 1275 core, where an active galactic nucleus emission dominates, rather than that from intracluster media. Therefore, we suggest that the source of the Fe-K{\alpha} line from NGC 1275 is likely a low-covering fraction molecular torus or a rotating molecular disk which probably extends from a pc to hundreds pc scale in the active galactic nucleus system., Comment: 20 pages, 8 figures, 6 tables, accepted for publication in PASJ

Published
2017
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23. Atmospheric gas dynamics in the Perseus cluster observed with Hitomi

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Canning, Rebecca E. A., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashi, Tasuku, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Shota, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Iwai, Masachika, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier, Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stéphane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Schartel, Norbert, Serlemtsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Łukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shin'ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Keigo, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shin'ichiro, Urry, C. Megan, Ursino, Eugenio, Wang, Qian H. S., Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, and Zoghbi, Abderahmen

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

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 cluster using observations obtained with the Hitomi satellite. After correcting for the point spread function of the telescope and using optically thin emission lines, we find that the line-of-sight velocity dispersion of the hot gas is remarkably low and mostly uniform. The velocity dispersion reaches maxima of approximately 200~km~s$^{-1}$ toward the central active galactic nucleus (AGN) and toward the AGN inflated north-western `ghost' bubble. Elsewhere within the observed region, the velocity dispersion appears constant around 100~km~s$^{-1}$. We also detect a velocity gradient with a 100~km~s$^{-1}$ amplitude across the cluster core, consistent with large-scale sloshing of the core gas. If the observed gas motions are isotropic, the kinetic pressure support is less than 10\% of the thermal pressure support in the cluster core. The well-resolved optically thin emission lines have Gaussian shapes, indicating that the turbulent driving scale is likely below 100~kpc, which is consistent with the size of the AGN jet inflated bubbles. We also report the first measurement of the ion temperature in the intracluster medium, which we find to be consistent with the electron temperature. In addition, we present a new measurement of the redshift to the brightest cluster galaxy NGC~1275., Comment: 52 pages, 16 figures, 8 tables, accepted for publication in PASJ

Published
2017
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24. Measurements of resonant scattering in the Perseus cluster core with Hitomi SXS

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Greg V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier O., Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stephane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sato, Toshiki, Sawada, Makoto, Schartel, Norbert, Serlemtsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Lukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shinichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shinichiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, Zoghbi, Abderahmen, Furukawa, Maki, and Ogorzalek, Anna

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

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 emission lines from highly ionized ions in galaxy clusters for the first time. In this series of papers, using the SXS we have measured the velocities of gas motions, metallicities and the multi-temperature structure of the gas in the core of the Perseus cluster. Here, we show that when inferring physical properties from line emissivities in systems like Perseus, the resonant scattering (RS) effect should be taken into account. In the Hitomi waveband, RS mostly affects the FeXXV He$\alpha$ line ($w$) - the strongest line in the spectrum. The flux measured by Hitomi in this line is suppressed by a factor ~1.3 in the inner ~30 kpc, compared to predictions for an optically thin plasma; the suppression decreases with the distance from the center. The $w$ line also appears slightly broader than other lines from the same ion. The observed distortions of the $w$ line flux, shape and distance dependence are all consistent with the expected effect of the resonant scattering in the Perseus core. By measuring the ratio of fluxes in optically thick ($w$) and thin (FeXXV forbidden, He$\beta$, Ly$\alpha$) lines, and comparing these ratios with predictions from Monte Carlo radiative transfer simulations, the velocities of gas motions have been obtained. The results are consistent with the direct measurements of gas velocities from line broadening described elsewhere in this series, although the systematic and statistical uncertainties remain significant. Further improvements in the predictions of line emissivities in plasma models, and deeper observations with future X-ray missions will enable RS measurements to provide powerful constraints on the amplitude and anisotropy of clusters gas motions., Comment: 30 pages, 17 figure, 6 tables, accepted for publication in PASJ

Published
2017
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25. Hitomi X-ray studies of Giant Radio Pulses from the Crab pulsar

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Iwai, Masachika, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier O., Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Oshimizu, Kenya, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stéphane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Schartel, Norbert, Serlemtsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Ł ukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shiníchiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shiníchiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, Zoghbi, Abderahmen, Terasawa, Toshio, Sekido, Mamoru, Takefuji, Kazuhiro, Kawai, Eiji, Misawa, Hiroaki, Tsuchiya, Fuminori, Yamazaki, Ryo, Kobayashi, Eiji, Kisaka, Shota, and Aoki, Takahiro

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

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 satellite Hitomi in the 2 -- 300 keV band and the Kashima NICT radio observatory in the 1.4 -- 1.7 GHz band with a net exposure of about 2 ks on 25 March 2016, just before the loss of the Hitomi mission.The timing performance of the Hitomi instruments was confirmed to meet the timing requirement and about 1,000 and 100 GRPs were simultaneously observed at the main and inter-pulse phases, respectively, and we found no apparent correlation between the giant radio pulses and the X-ray emission in either the main or inter-pulse phases.All variations are within the 2 sigma fluctuations of the X-ray fluxes at the pulse peaks, and the 3 sigma upper limits of variations of main- or inter- pulse GRPs are 22\% or 80\% of the peak flux in a 0.20 phase width, respectively, in the 2 -- 300 keV band.The values become 25\% or 110\% for main or inter-pulse GRPs, respectively, when the phase width is restricted into the 0.03 phase.Among the upper limits from the Hitomi satellite, those in the 4.5-10 keV and the 70-300 keV are obtained for the first time, and those in other bands are consistent with previous reports.Numerically, the upper limits of main- and inter-pulse GRPs in the 0.20 phase width are about (2.4 and 9.3) $\times 10^{-11}$ erg cm$^{-2}$, respectively. No significant variability in pulse profiles implies that the GRPs originated from a local place within the magnetosphere and the number of photon-emitting particles temporally increases.However, the results do not statistically rule out variations correlated with the GRPs, because the possible X-ray enhancement may appear due to a $>0.02$\% brightening of the pulse-peak flux under such conditions., Comment: 18 pages, 7 figure, 6 tables, accepted for publication in PASJ

Published
2017
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26. Search for Thermal X-ray Features from the Crab nebula with Hitomi Soft X-ray Spectrometer

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger, Brenneman, Laura W., Brown, Greg V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo S., Costantini, Elisa, de Plaa, Jelle, de Vries, Cor P., Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana M., Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko S., Hornschemeier, Ann, Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Kaastra, Jelle, Kallman, Tim, Kamae, Tsuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawai, Nobuyuki, Kelley, Richard L., Kilbourne, Caroline A., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Katsuji, Koyama, Shu, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lee, Shiu-Hang, Leutenegger, Maurice A., Limousin, Olivier O., Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Greg, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Hiroshi, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko K., Nobukawa, Masayoshi, Noda, Hirofumi, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stephane, Petre, Robert, Pinto, Ciro, Porter, Frederick S., Pottschmidt, Katja, Reynolds, Christopher S., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sato, Toshiki, Sawada, Makoto, Schartel, Norbert, Serlemtsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Lukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shinichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki T., Tashiro, Makoto S., Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi Go, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Uno, Shinichiro, Urry, C. Megan, Ursino, Eugenio, Watanabe, Shin, Werner, Norbert, Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Zhuravleva, Irina, Zoghbi, Abderahmen, Tominaga, Nozomu, and Moriya, Takashi J.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

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 mass and kinetic energy for an Fe-core collapse SN. Intensive searches were made for a massive shell that solves this discrepancy, but none has been detected. An alternative idea is that the SN1054 is an electron-capture (EC) explosion with a lower explosion energy by an order of magnitude than Fe-core collapse SNe. In the X-rays, imaging searches were performed for the plasma emission from the shell in the Crab outskirts to set a stringent upper limit to the X-ray emitting mass. However, the extreme brightness of the source hampers access to its vicinity. We thus employed spectroscopic technique using the X-ray micro-calorimeter onboard the Hitomi satellite. By exploiting its superb energy resolution, we set an upper limit for emission or absorption features from yet undetected thermal plasma in the 2-12 keV range. We also re-evaluated the existing Chandra and XMM-Newton data. By assembling these results, a new upper limit was obtained for the X-ray plasma mass of <~ 1Mo for a wide range of assumed shell radius, size, and plasma temperature both in and out of the collisional equilibrium. To compare with the observation, we further performed hydrodynamic simulations of the Crab SNR for two SN models (Fe-core versus EC) under two SN environments (uniform ISM versus progenitor wind). We found that the observed mass limit can be compatible with both SN models if the SN environment has a low density of <~ 0.03 cm-3 (Fe core) or <~ 0.1 cm-3 (EC) for the uniform density, or a progenitor wind density somewhat less than that provided by a mass loss rate of 10-5 Mo yr-1 at 20 km s-1 for the wind environment., Comment: PASJ in press. Figures are now properly included

Published
2017
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27. Multi-Year X-ray Variations of Iron-K and Continuum Emissions in the Young Supernova Remnant Cassiopeia A

Author

Sato, Toshiki, Maeda, Yoshitomo, Bamba, Aya, Katsuda, Satoru, Ohira, Yutaka, Yamazaki, Ryo, Masai, Kuniaki, Matsumoto, Hironori, Sawada, Makoto, Terada, Yukikatsu, Hughes, John P., and Ishida, Manabu

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We found simultaneous decrease of Fe-K line and 4.2-6 keV continuum of Cassiopeia A with the monitoring data taken by Chandra in 2000-2013. The flux change rates in the whole remnant are $-$0.65$\pm$0.02 \% yr$^{-1}$ in the 4.2--6.0 keV continuum and $-$0.6$\pm$0.1 \% yr$^{-1}$ in the Fe-K. In the eastern region where the thermal emission is considered to dominate, the variations show the largest values: $-$1.03$\pm$0.05 \% yr$^{-1}$ (4.2-6 keV band) and $-$0.6$\pm$0.1 \% yr$^{-1}$ (Fe-K line). In this region, the time evolution of the emission measure and the temperature have a decreasing trend. This could be interpreted as the adiabatic cooling with the expansion of $m = 0.66$. On the other hand, in the non-thermal emission dominated regions, the variations of the 4.2--6 keV continuum show the smaller rates: $-$0.60$\pm$0.04 \% yr$^{-1}$ in the southwestern region, $-$0.46$\pm$0.05 \% yr$^{-1}$ in the inner region and $+$0.00$\pm$0.07 \% yr$^{-1}$ in the forward shock region. In particular, the flux does not show significant change in the forward shock region. These results imply that a strong braking in the shock velocity has not been occurring in Cassiopeia A ($<$ 5 km s$^{-1}$ yr$^{-1}$). All of our results support that the X-ray flux decay in the remnant is mainly caused by the thermal components., Comment: 13 pages, 6 figures. Accepted for publication in ApJ

Published
2017
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28. A Systematic Study of the Thermal and Nonthermal Emission in the Supernova Remnant RCW 86 with Suzaku

Author

Tsubone, Yoshio, Sawada, Makoto, Bamba, Aya, Katsuda, Satoru, and Vink, Jacco

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Diffusive shock acceleration by the shockwaves in supernova remnants (SNRs) is widely accepted as the dominant source for Galactic cosmic rays. However, it is unknown what determines the maximum energy of accelerated particles. The surrounding environment could be one of the key parameters. The SNR RCW 86 shows both thermal and non-thermal X-ray emission with different spatial morphologies. These emission originate from the shock-heated plasma and accelerated electrons respectively, and their intensities reflect their density distributions. Thus, the remnant provides a suitable laboratory to test possible association between the acceleration efficiency and the environment. In this paper, we present results of spatially resolved spectroscopy of the entire remnant with Suzaku. The spacially-resolved spectra are well reproduced with a combination of a power-law for synchrotron emission and a two-component optically thin thermal plasma, corresponding to the shocked interstellar medium (ISM) with kT of 0.3-0.6 keV and Fe-dominated ejecta. It is discovered that the photon index of the nonthermal component becomes smaller with decreasing the emission measure of the shocked ISM, where the shock speed has remained high. This result implies that the maximum energy of accelerated electrons in RCW 86 is higher in the low-density and higher shock speed regions., Comment: 14 pages, 15 figures, ApJ accepted

Published
2016
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29. Basic Science of PET Imaging for Inflammatory Diseases

Author

Kubota, Kazuo, Ogawa, Mikako, Ji, Bin, Watabe, Tadashi, Zhang, Ming-Rong, Suzuki, Hiromi, Sawada, Makoto, Nishi, Kodai, Kudo, Takashi, Toyama, Hiroshi, editor, Li, Yaming, editor, Hatazawa, Jun, editor, Huang, Guang, editor, and Kubota, Kazuo, editor

Published
2020
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31. Hitomi constraints on the 3.5 keV line in the Perseus galaxy cluster

Author

Hitomi Collaboration, Aharonian, Felix A., Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Angelini, Lorella, Arnaud, Keith A., Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall W., Blandford, Roger D., Brenneman, Laura W., Brown, Gregory V., Bulbul, Esra, Cackett, Edward M., Chernyakova, Maria, Chiao, Meng P., Coppi, Paolo, Costantini, Elisa, de Plaa, Jelle, Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan E., Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew C., Ferrigno, Carlo, Foster, Adam R., Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi C., Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana, Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko, Hornschemeier, Ann E., Hoshino, Akio, Hughes, John P., Ichinohe, Yuto, Iizuka, Ryo, Inoue, Hajime, Inoue, Shota, Inoue, Yoshiyuki, Ishibashi, Kazunori, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Itoh, Masayuki, Iwai, Masachika, Iyomoto, Naoko, Kaastra, Jelle S., Kallman, Timothy, Kamae, Tuneyoshi, Kara, Erin, Kataoka, Jun, Katsuda, Satoru, Katsuta, Junichiro, Kawaharada, Madoka, Kawai, Nobuyuki, Kelley, Richard L., Khangulyan, Dmitry, Kilbourne, Caroline A., King, Ashley L., Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Shu, Koyama, Katsuji, Kretschmar, Peter, Krimm, Hans A., Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lebrun, Francois, Lee, Shiu-Hang, Leutenegger, Maurice, Limousin, Olivier, Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Grzegorz M., Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian R., Mehdipour, Missagh, Miller, Eric D., Miller, Jon M., Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Moseley, Harvey, Mukai, Koji, Murakami, Hiroshi, Murakami, Toshio, Mushotzky, Richard F., Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakano, Toshio, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Kumiko, Nobukawa, Masayoshi, Noda, Hirofumi, Nomachi, Masaharu, O'Dell, Steve L., Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stephane, Parmar, Arvind, Petre, Robert, Pinto, Ciro, Pohl, Martin, Porter, F. Scott, Pottschmidt, Katja, Ramsey, Brian D., Reynolds, Christopher S., Russell, Helen R., Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sameshima, Hiroaki, Sasaki, Toru, Sato, Goro, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Schartel, Norbert, Serlemitsos, Peter J., Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall K., Soong, Yang, Stawarz, Lukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew E., Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shin'ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Keisuke, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki, Tashiro, Makoto, Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Ueno, Shiro, Uno, Shin'ichiro, Urry, C. Meg, Ursino, Eugenio, de Vries, Cor P., Watanabe, Shin, Werner, Norbert, Wik, Daniel R., Wilkins, Dan R., Williams, Brian J., Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Yoshida, Atsumasa, Zhuravleva, Irina, and Zoghbi, Abderahmen

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

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 various massive systems, such as galaxies and clusters, including the Perseus cluster. We have analyzed the Hitomi first-light observation of the Perseus cluster. The emission line expected for Perseus based on the XMM-Newton signal from the large cluster sample under the dark matter decay scenario is too faint to be detectable in the Hitomi data. However, the previously reported 3.5 keV flux from Perseus was anomalously high compared to the sample-based prediction. We find no unidentified line at the reported high flux level. Taking into account the XMM measurement uncertainties for this region, the inconsistency with Hitomi is at a 99% significance for a broad dark-matter line and at 99.7% for a narrow line from the gas. We do not find anomalously high fluxes of the nearby faint K line or the Ar satellite line that were proposed as explanations for the earlier 3.5 keV detections. We do find a hint of a broad excess near the energies of high-n transitions of Sxvi (E=3.44 keV rest-frame) -- a possible signature of charge exchange in the molecular nebula and another proposed explanation for the unidentified line. While its energy is consistent with XMM pn detections, it is unlikely to explain the MOS signal. A confirmation of this interesting feature has to wait for a more sensitive observation with a future calorimeter experiment., Comment: Discussion of systematics significantly expanded. 9 pages, 5 figures; ApJ Lett. in press

Published
2016
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32. The Quiescent Intracluster Medium in the Core of the Perseus Cluster

Author

Hitomi Collaboration, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steven W., Anabuki, Naohisa, Angelini, Lorella, Arnaud, Keith, Audard, Marc, Awaki, Hisamitsu, Axelsson, Magnus, Bamba, Aya, Bautz, Marshall, Blandford, Roger, Brenneman, Laura, Brown, Gregory V., Bulbul, Esra, Cackett, Edward, Chernyakova, Maria, Chiao, Meng, Coppi, Paolo, Costantini, Elisa, de Plaa, Jelle, Herder, Jan-Willem den, Done, Chris, Dotani, Tadayasu, Ebisawa, Ken, Eckart, Megan, Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew, Ferrigno, Carlo, Foster, Adam, Fujimoto, Ryuichi, Fukazawa, Yasushi, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi, Gandhi, Poshak, Giustini, Margherita, Goldwurm, Andrea, Gu, Liyi, Guainazzi, Matteo, Haba, Yoshito, Hagino, Kouichi, Hamaguchi, Kenji, Harrus, Ilana, Hatsukade, Isamu, Hayashi, Katsuhiro, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko, Hornschemeier, Ann, Hoshino, Akio, Hughes, John, Iizuka, Ryo, Inoue, Hajime, Inoue, Yoshiyuki, Ishibashi, Kazunori, Ishida, Manabu, Ishikawa, Kumi, Ishisaki, Yoshitaka, Itoh, Masayuki, Iyomoto, Naoko, Kaastra, Jelle, Kallman, Timothy, Kamae, Tuneyoshi, Kara, Erin, Kataoka, Jun, Katsuda, Satoru, Katsuta, Junichiro, Kawaharada, Madoka, Kawai, Nobuyuki, Kelley, Richard, Khangulyan, Dmitry, Kilbourne, Caroline, King, Ashley, Kitaguchi, Takao, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Koyama, Shu, Koyama, Katsuji, Kretschmar, Peter, Krimm, Hans, Kubota, Aya, Kunieda, Hideyo, Laurent, Philippe, Lebrun, Francois, Lee, Shiu-Hang, Leutenegger, Maurice, Limousin, Olivier, Loewenstein, Michael, Long, Knox S., Lumb, David, Madejski, Grzegorz, Maeda, Yoshitomo, Maier, Daniel, Makishima, Kazuo, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian, Mehdipour, Missagh, Miller, Eric, Miller, Jon, Mineshige, Shin, Mitsuda, Kazuhisa, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Moseley, Harvey, Mukai, Koji, Murakami, Hiroshi, Murakami, Toshio, Mushotzky, Richard, Nagino, Ryo, Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakano, Toshio, Nakashima, Shinya, Nakazawa, Kazuhiro, Nobukawa, Masayoshi, Noda, Hirofumi, Nomachi, Masaharu, O'Dell, Steve, Odaka, Hirokazu, Ohashi, Takaya, Ohno, Masanori, Okajima, Takashi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stephane, Parmar, Arvind, Petre, Robert, Pinto, Ciro, Pohl, Martin, Porter, F. Scott, Pottschmidt, Katja, Ramsey, Brian, Reynolds, Christopher, Russell, Helen, Safi-Harb, Samar, Saito, Shinya, Sakai, Kazuhiro, Sameshima, Hiroaki, Sato, Goro, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Schartel, Norbert, Serlemitsos, Peter, Seta, Hiromi, Shidatsu, Megumi, Simionescu, Aurora, Smith, Randall, Soong, Yang, Stawarz, Lukasz, Sugawara, Yasuharu, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Tadayuki, Takeda, Shin'ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Keisuke, Tamura, Takayuki, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki, Tashiro, Makoto, Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi, Uchida, Hiroyuki, Uchiyama, Hideki, Uchiyama, Yasunobu, Ueda, Shutaro, Ueda, Yoshihiro, Ueno, Shiro, Uno, Shin'ichiro, Urry, Meg, Ursino, Eugenio, de Vries, Cor, Watanabe, Shin, Werner, Norbert, Wik, Daniel, Wilkins, Dan, Williams, Brian, Yamada, Shinya, Yamaguchi, Hiroya, Yamaok, Kazutaka, Yamasaki, Noriko Y., Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Yoshida, Atsumasa, Yuasa, Takayuki, Zhuravleva, Irina, and Zoghbi, Abderahmen

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Clusters of galaxies are the most massive gravitationally-bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. It can enable new insights into mechanical energy injection by the central supermassive black hole and the use of hydrostatic equilibrium for the determination of cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50 million K diffuse hot plasma filling its gravitational potential well. The Active Galactic Nucleus of the central galaxy NGC1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These likely induce motions in the intracluster medium and heat the inner gas preventing runaway radiative cooling; a process known as Active Galactic Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus cluster core, which reveal a remarkably quiescent atmosphere where the gas has a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s is found across the 60 kpc image of the cluster core. Turbulent pressure support in the gas is 4% or less of the thermodynamic pressure, with large scale shear at most doubling that estimate. We infer that total cluster masses determined from hydrostatic equilibrium in the central regions need little correction for turbulent pressure., Comment: 31 pages, 11 Figs, published in Nature July 8

Published
2016
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33. Discovery of X-ray Emission from the Galactic Supernova Remnant G32.8-0.1 with Suzaku

Author

Bamba, Aya, Terada, Yukikatsu, Hewitt, John, Petre, Robert, Angelini, Lorella, Safi-Harb, Samar, Zhou, Ping, Bocchino, Fabrizio, and Sawada, Makoto

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the first dedicated X-ray study of the supernova remnant (SNR) G32.8-0.1 (Kes 78) with Suzaku. X-ray emission from the whole SNR shell has been detected for the first time. The X-ray morphology is well correlated with the emission from the radio shell, while anti-correlated with the molecular cloud found in the SNR field. The X-ray spectrum shows not only conventional low-temperature (kT ~ 0.6 keV) thermal emission in a non-equilibrium ionization state, but also a very high temperature (kT ~ 3.4 keV) component with a very low ionization timescale (~ 2.7e9 cm^{-3}s), or a hard non-thermal component with a photon index Gamma~2.3. The average density of the low-temperature plasma is rather low, of the order of 10^{-3}--10^{-2} cm^{-3}, implying that this SNR is expanding into a low-density cavity. We discuss the X-ray emission of the SNR, also detected in TeV with H.E.S.S., together with multi-wavelength studies of the remnant and other gamma-ray emitting SNRs, such as W28 and RCW 86. Analysis of a time-variable source, 2XMM J185114.3-000004, found in the northern part of the SNR, is also reported for the first time. Rapid time variability and a heavily absorbed hard X-ray spectrum suggest that this source could be a new supergiant fast X-ray transient., Comment: 20 pages, 14 figures, ApJ, in press

Published
2016
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34. New Identification of the Mixed-Morphology Supernova Remnant G298.6-0.0 with Possible Gamma-ray Association

Author

Bamba, Aya, Sawada, Makoto, Nakano, Yuto, Terada, Yukikatsu, Hewitt, John, Petre, Robert, and Angelini, Lorella

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present an X-ray analysis on the Galactic supernova remnant (SNR) G298.6-0.0 with Suzaku. The X-ray image shows a center-filled structure inside the radio shell, implying this SNR is categorized as a mixed-morphology (MM) SNR. The spectrum is well reproduced by a single temperature plasma model in ionization equilibrium, with a temperature of 0.78 (0.70-0.87) keV. The total plasma mass of 30 solar mass indicates that the plasma has interstellar medium origin. The association with a GeV gamma-ray source 3FGL J1214.0-6236 on the shell of the SNR is discussed, in comparison with other MM SNRs with GeV gamma-ray associations. It is found that the flux ratio between absorption-corrected thermal X-rays and GeV gamma-rays decreases as the MM SNRs evolve to larger physical sizes. The absorption-corrected X-ray flux of G298.6-0.0 and the GeV gamma-ray flux of 3FGL J1214.0-6236 closely follow this trend, implying that 3FGL J1214.0-6236 is likely to be the GeV counterpart of G298.6-0.0., Comment: 11 pages, 6 figures, PASJ, in press

Published
2015
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35. The ASTRO-H X-ray Astronomy Satellite

Author

Takahashi, Tadayuki, Mitsuda, Kazuhisa, Kelley, Richard, Aharonian, Felix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steve, Anabuki, Naohisa, Angelini, Lorella, Arnaud, Keith, Asai, Makoto, Audard, Marc, Awaki, Hisamitsu, Azzarello, Philipp, Baluta, Chris, Bamba, Aya, Bando, Nobutaka, Bautz, Marshall, Bialas, Thomas, Blandford, Roger, Boyce, Kevin, Brenneman, Laura, Brown, Greg, Cackett, Edward, Canavan, Edgar, Chernyakova, Maria, Chiao, Meng, Coppi, Paolo, Costantini, Elisa, de Plaa, Jelle, Herder, Jan-Willem den, DiPirro, Michael, Done, Chris, Dotani, Tadayasu, Doty, John, Ebisawa, Ken, Eckart, Megan, Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew, Ferrigno, Carlo, Foster, Adam, Fujimoto, Ryuichi, Fukazawa, Yasushi, Funk, Stefan, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi, Gandhi, Poshak, Gilmore, Kirk, Guainazzi, Matteo, Haas, Daniel, Haba, Yoshito, Hamaguchi, Kenji, Harayama, Atsushi, Hatsukade, Isamu, Hayashi, Takayuki, Hayashi, Katsuhiro, Hayashida, Kiyoshi, Hiraga, Junko, Hirose, Kazuyuki, Hornschemeier, Ann, Hoshino, Akio, Hughes, John, Hwang, Una, Iizuka, Ryo, Inoue, Yoshiyuki, Ishibashi, Kazunori, Ishida, Manabu, Ishikawa, Kumi, Ishimura, Kosei, Ishisaki, Yoshitaka, Ito, Masayuki, Iwata, Naoko, Iyomoto, Naoko, Jewell, Chris, Kaastra, Jelle, Kallman, Timothy, Kamae, Tuneyoshi, Kataoka, Jun, Katsuda, Satoru, Katsuta, Junichiro, Kawaharada, Madoka, Kawai, Nobuyuki, Kawano, Taro, Kawasaki, Shigeo, Khangulyan, Dmitry, Kilbourne, Caroline, Kimball, Mark, Kimura, Masashi, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Konami, Saori, Kosaka, Tatsuro, Koujelev, Alex, Koyama, Katsuji, Krimm, Hans, Kubota, Aya, Kunieda, Hideyo, LaMassa, Stephanie, Laurent, Philippe, Lebrun, Franccois, Leutenegger, Maurice, Limousin, Olivier, Loewenstein, Michael, Long, Knox, Lumb, David, Madejski, Grzegorz, Maeda, Yoshitomo, Makishima, Kazuo, Markevitch, Maxim, Masters, Candace, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, Mcguinness, Daniel, McNamara, Brian, Miko, Joseph, Miller, Jon, Miller, Eric, Mineshige, Shin, Minesugi, Kenji, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Koji, Mori, Hideyuki, Moroso, Franco, Muench, Theodore, Mukai, Koji, Murakami, Hiroshi, Murakami, Toshio, Mushotzky, Richard, Nagano, Housei, Nagino, Ryo, Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakashima, Shinya, Nakazawa, Kazuhiro, Namba, Yoshiharu, Natsukari, Chikara, Nishioka, Yusuke, Nobukawa, Masayoshi, Noda, Hirofumi, Nomachi, Masaharu, Dell, Steve O', Odaka, Hirokazu, Ogawa, Hiroyuki, Ogawa, Mina, Ogi, Keiji, Ohashi, Takaya, Ohno, Masanori, Ohta, Masayuki, Okajima, Takashi, Okamoto, Atsushi, Okazaki, Tsuyoshi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, St'ephane, Parmar, Arvind, Petre, Robert, Pinto, Ciro, Pohl, Martin, Pontius, James, Porter, F. Scott, Pottschmidt, Katja, Ramsey, Brian, Reis, Rubens, Reynolds, Christopher, Ricci, Claudio, Russell, Helen, Safi-Harb, Samar, Saito, Shinya, Sakai, Shin-ichiro, Sameshima, Hiroaki, Sato, Goro, Sato, Yoichi, Sato, Kosuke, Sato, Rie, Sawada, Makoto, Serlemitsos, Peter, Seta, Hiromi, Shibano, Yasuko, Shida, Maki, Shimada, Takanobu, Shinozaki, Keisuke, Shirron, Peter, Simionescu, Aurora, Simmons, Cynthia, Smith, Randall, Sneiderman, Gary, Soong, Yang, Stawarz, Lukasz, Sugawara, Yasuharu, Sugita, Hiroyuki, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takahashi, Hiroaki, Takeda, Shin-ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tamura, Keisuke, Tanaka, Takaaki, Tanaka, Yasuo, Tanaka, Yasuyuki, Tashiro, Makoto, Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yohko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi, Uchida, Hiroyuki, Uchiyama, Yasunobu, Uchiyama, Hideki, Ueda, Yoshihiro, Ueda, Shutaro, Ueno, Shiro, Uno, Shinichiro, Urry, Meg, Ursino, Eugenio, de Vries, Cor, Wada, Atsushi, Watanabe, Shin, Watanabe, Tomomi, Werner, Norbert, White, Nicholas, Wilkins, Dan, Yamada, Takahiro, Yamada, Shinya, Yamaguchi, Hiroya, Yamaoka, Kazutaka, Yamasaki, Noriko, Yamauchi, Makoto, Yamauchi, Shigeo, Yaqoob, Tahir, Yatsu, Yoichi, Yonetoku, Daisuke, Yoshida, Atsumasa, Yuasa, Takayuki, Zhuravleva, Irina, Zoghbi, Abderahmen, and ZuHone, John

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions developed by the Institute of Space and Astronautical Science (ISAS), with a planned launch in 2015. The ASTRO-H mission is equipped with a suite of sensitive instruments with the highest energy resolution ever achieved at E > 3 keV and a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. The simultaneous broad band pass, coupled with the high spectral resolution of Delta E < 7 eV of the micro-calorimeter, will enable a wide variety of important science themes to be pursued. ASTRO-H is expected to provide breakthrough results in scientific areas as diverse as the large-scale structure of the Universe and its evolution, the behavior of matter in the gravitational strong field regime, the physical conditions in sites of cosmic-ray acceleration, and the distribution of dark matter in galaxy clusters at different redshifts., Comment: 24 pages, 18 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray"

Published
2014
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37. Dark matter search in the Perseus cluster with simultaneous analysis of Hitomi and Suzaku data.

Author

Fukuichi, Makoto, Kitamoto, Shunji, Sawada, Makoto, and Tamura, Takayuki

Subjects
DARK matter, CLUSTER analysis (Statistics), GALAXY clusters, X-ray spectrometers, STERILE neutrinos, X-ray astronomy, WEAKLY interacting massive particles, MASS transfer
Abstract

The reported detection of a 3.5 keV emission line in the Perseus cluster, possibly originating from dark matter decay, is still under scrutiny. Despite extensive observations, the detection has not yet been confirmed, and its origin remains a topic of active debate. Most of the previous searches relied on spectroscopy with X-ray charge-coupled devices, such as the X-ray Imaging Spectrometer on Suzaku. Although this provided a large amount of observational data, it only offered moderate spectral resolution. The X-ray astronomy satellite Hitomi offers new results using its high-resolution X-ray spectrometer (Soft X-ray Spectrometer). However, the data gathered were somewhat limited in terms of statistics. In this work, we present the results of a new spectral analysis of the Perseus cluster that combines the spectra from the XIS and SXS, along with the Soft X-ray Imager on Hitomi, thereby complementing each other's capability. Our search was conducted for a line emission or absorption in the energy range of 2.6–5.9 keV assuming the Navarro–Frenk–White mass distribution with a concentration parameter of 5.0 and virial radius, r 200, of 1.79 Mpc. We also considered the instrumental systematic uncertainty caused by the effective area calibration, which we empirically evaluated using the Crab Nebula spectra. On combining these results, we found no significant line features above the baryonic thermal emission from the intra-cluster medium. The upper limit at 3.5 keV, at a 3σ confidence level, is tightly constrained to 4.2 × 10−5 photons cm−2 s−1 for the |$15^{\prime }$| circular sky region, which encloses a dark matter mass of |$1.67\times 10^{14}\, M_{\odot }$|⁠ , assuming a line velocity dispersion of 180 km s−1. This constraint is three times tighter than the previous one, which only used the SXS. On the basis of these findings, we provide the upper limit of the dark matter decay rate and the mixing angle for the sterile neutrino origin. [ABSTRACT FROM AUTHOR]

Published
2024
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38. Discovery of Enhanced Radiative Recombination Continua of He-like Iron and Calcium from IC 443 and Its Implications

Author

Ohnishi, Takao, Uchida, Hiroyuki, Tsuru, Takeshi Go, Koyama, Katsuji, Masai, Kuniaki, and Sawada, Makoto

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present deep observations of the Galactic supernova remnant IC 443 with the {\it Suzaku X-ray satellite}. We find prominent K-shell lines from iron and nickel, together with a triangle residual at 8--10~keV, which corresponds to the energy of the radiative recombination continuum (RRC) of He-like iron. In addition, the wavy residuals have been seen at $\sim$5.1 and $\sim$5.5~keV. We confirm that the residuals show the first enhanced RRCs of He- and H-like calcium found in supernova remnants. These facts provide robust evidence for the recombining plasma. We reproduce the plasma in the 3.7--10~keV band using a recombining plasma model at the electron temperature 0.65~keV. The recombination parameter $n_{\rm e}t$ ($n_{\rm e}$ is electron density and $t$ is elapsed time after formation of a recombining plasma) and abundances of iron and nickel are strongly correlated, and hence the errors are large. On the other hand, the ratio of nickel to iron relative to the solar abundances is well constrained to 11$^{+4}_{-3}$ (1$\sigma$). A possibility is that the large abundance ratio is a result of an asymmetric explosion of the progenitor star., Comment: 4 pages, 5 figures, published in ApJ

Published
2014
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41. Synchrotron X-ray diagnostics of cutoff shape of nonthermal electron spectrum at young supernova remnants

Author

Yamazaki, Ryo, Ohira, Yutaka, Sawada, Makoto, and Bamba, Aya

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Synchrotron X-rays can be a useful tool to investigate electron acceleration at young supernova remnants (SNRs). At present, since the magnetic field configuration around the shocks of SNRs is uncertain, it is not clear whether electron acceleration is limited by SNR age, synchrotron cooling, or even escape from the acceleration region. We study whether the acceleration mechanism can be constrained by the cutoff shape of the electron spectrum around the maximum energy. We derive analytical formulae of the cutoff shape in each case where the maximum electron energy is determined by SNR age, synchrotron cooling and escape from the shock. They are related to the energy dependence of the electron diffusion coefficient. Next, we discuss whether information on the cutoff shape can be provided by observations in the near future which will simply give the photon indices and the flux ratios in the soft and hard X-ray bands. We find that if the power-law index of the electron spectrum is independently determined by other observations, then we can constrain the cutoff shape by comparing theoretical predictions of the photon indices and/or the flux ratios with observed data which will be measured by NuSTAR and/or ASTRO-H. Such study is helpful in understanding the acceleration mechanism. In particular, it will supply another independent constraint on the magnetic field strength around the shocks of SNRs., Comment: 15 pages, 6 figures

Published
2013
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42. X-Ray Observations of the W51 Complex with Suzaku

Author

Hanabata, Yoshitaka, Sawada, Makoto, Katagiri, Hideaki, Bamba, Aya, and Fukazawa, Yasushi

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present a detailed analysis of the X-ray emission from the middle-aged supernova remnant W51C and star-forming region W51B with Suzaku. The soft X-ray emission from W51C is well represented by an optically thin thermal plasma in the non-equilibrium ionization state with a temperature of $\sim$0.7 keV. The elemental abundance of Mg is significantly higher than the solar value. We find no significant feature of an over-ionized plasma in W51C. The hard X-ray emission is spatially coincident with the molecular clouds associated with W51B, overlapping with W51C. The spectrum is represented by an optically thin thermal plasma with a temperature of $\sim$5 keV or a powerlaw model with a photon index of $\sim$2.2. The emission probably has diffuse nature since its luminosity of 1$\times10^{34}$ erg s$^{-1}$ in the 0.5-10 keV band cannot be explained by the emission from point sources in this region. We discuss the possibility that the hard X-ray emission comes from stellar winds of OB stars in W51B or accelerated particles in W51C., Comment: 11 pages, 5 figures, accepted for publication in PASJ

Published
2012
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43. The ASTRO-H X-ray Observatory

Author

Takahashi, Tadayuki, Mitsuda, Kazuhisa, Kelley, Richard, Aharonian, Henri AartsFelix, Akamatsu, Hiroki, Akimoto, Fumie, Allen, Steve, Anabuki, Naohisa, Angelini, Lorella, Arnaud, Keith, Asai, Makoto, Audard, Marc, Awaki, Hisamitsu, Azzarello, Philipp, Baluta, Chris, Bamba, Aya, Bando, Nobutaka, Bautz, Mark, Blandford, Roger, Boyce, Kevin, Brown, Greg, Cackett, Ed, Chernyakova, Maria, Coppi, Paolo, Costantini, Elisa, de Plaa, Jelle, Herder, Jan-Willem den, DiPirro, Michael, Done, Chris, Dotani, Tadayasu, Doty, John, Ebisawa, Ken, Eckart, Megan, Enoto, Teruaki, Ezoe, Yuichiro, Fabian, Andrew, Ferrigno, Carlo, Foster, Adam, Fujimoto, Ryuichi, Fukazawa, Yasushi, Funk, Stefan, Furuzawa, Akihiro, Galeazzi, Massimiliano, Gallo, Luigi, Gandhi, Poshak, Gendreau, Keith, Gilmore, Kirk, Haas, Daniel, Haba, Yoshito, Hamaguchi, Kenji, Hatsukade, Isamu, Hayashi, Takayuki, Hayashida, Kiyoshi, Hiraga, Junko, Hirose, Kazuyuki, Hornschemeier, Ann, Hoshino, Akio, Hughes, John, Hwang, Una, Iizuka, Ryo, Inoue, Yoshiyuki, Ishibashi, Kazunori, Ishida, Manabu, Ishimura, Kosei, Ishisaki, Yoshitaka, Ito, Masayuki, Iwata, Naoko, Iyomoto, Naoko, Kaastra, Jelle, Kallman, Timothy, Kamae, Tuneyoshi, Kataoka, Jun, Katsuda, Satoru, Kawahara, Hajime, Kawaharada, Madoka, Kawai, Nobuyuki, Kawasaki, Shigeo, Khangaluyan, Dmitry, Kilbourne, Caroline, Kimura, Masashi, Kinugasa, Kenzo, Kitamoto, Shunji, Kitayama, Tetsu, Kohmura, Takayoshi, Kokubun, Motohide, Kosaka, Tatsuro, Koujelev, Alex, Koyama, Katsuji, Krimm, Hans, Kubota, Aya, Kunieda, Hideyo, LaMassa, Stephanie, Laurent, Philippe, Lebrun, Francois, Leutenegger, Maurice, Limousin, Olivier, Loewenstein, Michael, Long, Knox, Lumb, David, Madejski, Grzegorz, Maeda, Yoshitomo, Makishima, Kazuo, Marchand, Genevieve, Markevitch, Maxim, Matsumoto, Hironori, Matsushita, Kyoko, McCammon, Dan, McNamara, Brian, Miller, Jon, Miller, Eric, Mineshige, Shin, Minesugi, Kenji, Mitsuishi, Ikuyuki, Miyazawa, Takuya, Mizuno, Tsunefumi, Mori, Hideyuki, Mori, Koji, Mukai, Koji, Murakami, Toshio, Murakami, Hiroshi, Mushotzky, Richard, Nagano, Housei, Nagino, Ryo, Nakagawa, Takao, Nakajima, Hiroshi, Nakamori, Takeshi, Nakazawa, Kazuhiro, Namba, Yoshiharu, Natsukari, Chikara, Nishioka, Yusuke, Nobukawa, Masayoshi, Nomachi, Masaharu, Dell, Steve O', Odaka, Hirokazu, Ogawa, Hiroyuki, Ogawa, Mina, Ogi, Keiji, Ohashi, Takaya, Ohno, Masanori, Ohta, Masayuki, Okajima, Takashi, Okamoto, Atsushi, Okazaki, Tsuyoshi, Ota, Naomi, Ozaki, Masanobu, Paerels, Frits, Paltani, Stephane, Parmar, Arvind, Petre, Robert, Pohl, Martin, Porter, F. Scott, Ramsey, Brian, Reis, Rubens, Reynolds, Christopher, Russell, Helen, Safi-Harb, Samar, Sakai, Shin-ichiro, Sameshima, Hiroaki, Sanders, Jeremy, Sato, Goro, Sato, Rie, Sato, Yoichi, Sato, Kosuke, Sawada, Makoto, Serlemitsos, Peter, Seta, Hiromi, Shibano, Yasuko, Shida, Maki, Shimada, Takanobu, Shinozaki, Keisuke, Shirron, Peter, Simionescu, Aurora, Simmons, Cynthia, Smith, Randall, Sneiderman, Gary, Soong, Yang, Stawarz, Lukasz, Sugawara, Yasuharu, Sugita, Hiroyuki, Sugita, Satoshi, Szymkowiak, Andrew, Tajima, Hiroyasu, Takahashi, Hiromitsu, Takeda, Shin-ichiro, Takei, Yoh, Tamagawa, Toru, Tamura, Takayuki, Tamura, Keisuke, Tanaka, Takaaki, Tanaka, Yasuo, Tashiro, Makoto, Tawara, Yuzuru, Terada, Yukikatsu, Terashima, Yuichi, Tombesi, Francesco, Tomida, Hiroshi, Tsuboi, Yoko, Tsujimoto, Masahiro, Tsunemi, Hiroshi, Tsuru, Takeshi, Uchida, Hiroyuki, Uchiyama, Yasunobu, Uchiyama, Hideki, Ueda, Yoshihiro, Ueno, Shiro, Uno, Shinichiro, Urry, Meg, Ursino, Eugenio, de Vries, Cor, Wada, Atsushi, Watanabe, Shin, Werner, Norbert, White, Nicholas, Yamada, Takahiro, Yamada, Shinya, Yamaguchi, Hiroya, Yamasaki, Noriko, Yamauchi, Shigeo, Yamauchi, Makoto, Yatsu, Yoichi, Yonetoku, Daisuke, Yoshida, Atsumasa, and Yuasa, Takayuki

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes., Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray"

Published
2012
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44. Recombining Plasma and Hard X-ray Filament in the Mixed-Morphology Supernova Remnant W44

Author

Uchida, Hiroyuki, Koyama, Katsuji, Yamaguchi, Hiroya, Sawada, Makoto, Ohnishi, Takao, Tsuru, Takeshi Go, Tanaka, Takaaki, Yoshiike, Satoshi, and Fukui, Yasuo

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report new features of the typical mixed-morphology (MM) supernova remnant (SNR) W44. In the X-ray spectra obtained with Suzaku, radiative recombination continua (RRCs) of highly ionized atoms are detected for the first time. The spectra are well reproduced by a thermal plasma in a recombining phase. The best-fit parameters suggest that the electron temperature of the shock-heated matters cooled down rapidly from $\sim1$,keV to $\sim 0.5$,keV, possibly due to adiabatic expansion (rarefaction) occurred $\sim20,000$ years ago. We also discover hard X-ray emission which shows an arc-like structure spatially-correlated with a radio continuum filament. The surface brightness distribution shows a clear anti-correlation with $^{12}$CO (J=2-1) emission from a molecular cloud observed with NANTEN2. While the hard X-ray is most likely due to a synchrotron enhancement in the vicinity of the cloud, no current model can quantitatively predict the observed flux., Comment: 10 pages, 5 figures, accepted for publication in PASJ

Published
2012
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45. X-Ray Observations of the Supernova Remnant W28 with Suzaku --- I. Spectral Study of the Recombining Plasma

Author

Sawada, Makoto and Koyama, Katsuji

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the Suzaku results of the mixed-morphology supernova remnant W28. The X-ray spectra of the central region of W28 exhibit many bright emission lines from highly ionized atoms. An optically thin thermal plasma in collisional ionization equilibrium, either of single-temperature or multi-temperature failed to reproduce the data with line-like and bump-like residuals at the Si Lyman$\alpha$ energy and at 2.4--5.0 keV, respectively. The bumps probably correspond to radiative recombination continua from He-like Si and S. A simple recombining plasma model nicely fit the bump structures, but failed to fit low energy bands. The overall spectra can be fit with a multi-ionization temperature plasma with a common electron temperature. The multi-ionization temperatures are interpreted as elemental difference of ionization and recombination timescales. These results prefer the rarefaction scenario for the origin of the recombining plasma., Comment: Accepted for publication in PASJ; Vol.64 No. 4 (8 pages, 5 figures)

Published
2012
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46. Suzaku Discovery of Twin Thermal Plasma from the Tornado Nebula

Author

Sawada, Makoto, Tsuru, Takeshi Go, Koyama, Katsuji, and Oka, Tomoharu

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Tornado nebula (G357.7-0.1) is a mysterious radio source with bright "head" and faint "tail" located in the direction of the Galactic center (GC) region. We here report the discovery of two diffuse X-ray sources at the head and tail of the Tornado with the Suzaku satellite. We found emission lines from highly ionized atoms in the two sources. The spectra are reproduced by an optically thin thermal plasma with a common temperature of 0.6-0.7 keV. The interstellar absorption (NH) of these sources are the same and are slightly larger than that of the GC distance. Since the estimated distance using the NH value is consistent with the radio observation of the Tornado, these X-ray sources are likely associated with the Tornado nebula. The twin-plasma morphology at the both ends of the Tornado suggests that the system is a bipolar/outflow source., Comment: Accepted for publication in PASJ (7 pages, 4 figures)

Published
2011
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48. X-Ray Observations of the Sagittarius D HII Region toward the Galactic Center with Suzaku

Author

Sawada, Makoto, Tsujimoto, Masahiro, Koyama, Katsuji, Law, Casey J., Tsuru, Takeshi Go, and Hyodo, Yoshiaki

Subjects
Astrophysics
Abstract

We present a Suzaku X-ray study of the Sagittarius D (Sgr D) HII region in the Galactic center region. Two 18'x18' images by the X-ray Imaging Spectrometer (XIS) encompass the entire Sgr D complex. Thanks to the low background, XIS discovered two diffuse sources with low surface brightness and obtained their high signal-to-noise ratio spectra. One is associated with the core of the Sgr D HII region, arising from the young stellar cluster. The other is a new object in the vicinity of the region. We also present 3.5 cm and 6.0 cm radio continuum maps of the new source using the 100 m Green Bank Telescope. We conclude that the source is a new supernova remnant (SNR; G1.2--0.0) based on: (1) the 0.9+/-0.2 keV thermal X-ray spectrum with emission lines from highly ionized atoms; (2) the diffuse nature with an apparent extent of ~10 pc at the Galactic center distance inferred from the X-ray absorption (~8.5x10^{22} cm^{-2}); and (3) the nonthermal radio continuum spectral index (~-0.5). Our discovery of an SNR in the Sgr D HII region leads to a revision of the view of this system, which had been considered to be a thermal HII region and its environment., Comment: Accepted for publication in PASJ

Published
2008

49. Discovery of Extended X-Ray emission from the unidentified TeV source HESS J1614-518 using the Suzaku Satellite

Author

Matsumoto, Hironori, Uchiyama, Hideki, Sawada, Makoto, Tsuru, Takeshi G., Koyama, Katsuji, Katagiri, Hideaki, Yamazaki, Ryo, Bamba, Aya, Kohri, Kazunori, Mori, Koji, and Uchiyama, Yasunobu

Subjects
Astrophysics
Abstract

We report the Suzaku results of HESS J1614-518, which is the brightest extended TeV gamma-ray source discovered in the Galactic plane survey conducted using the H.E.S.S. telescope. We discovered three X-ray objects in the field of view of the X-ray Imaging Spectrometer (XIS), which were designated as Suzaku J1614-5141 (src A), Suzaku J1614-5152 (src B), and Suzaku J1614-5148 (src C). Src A is an extended source located at the peak position of HESS J1614-518, and therefore it is a plausible counterpart to HESS J1614-518. The X-ray flux in the 2-10 keV band is 5e-13 erg/s/cm^2, which is an order of magnitude smaller than the TeV flux. The photon index is 1.7, which is smaller than the canonical value of synchrotron emissions from high-energy electrons found in some supernova remnants. These findings present a challenge to models in which the origin of the TeV emission is the inverse Compton scattering of the cosmic microwave background by accelerated electrons that emit X-rays via synchrotron emission. Src B is located at a relatively dim region in the TeV band image; however, its hydrogen column density is the same as that of src A. Therefore, src B may also be physically related to HESS J1614-518. Src C is a foreground late-type B star. We also discovered a soft extended X-ray emission near HESS J1614-518., Comment: Accepted for publication in PASJ vol. 60 Suzaku Special Issue 2

Published
2007
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