X-ray spectra of Sagittarius A East and diffuse X-ray background near the Galactic center

Ono, Akira; Uchiyama, Hideki; Yamauchi, Shigeo; Nobukawa, Masayoshi; Nobukawa, Kumiko K.; Koyama, K.

doi:10.1093/pasj/psz025

Cited by 11 publications

(15 citation statements)

References 44 publications

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“…Our best-fit temperatures are similar to that from the XMM-Newton study by Sakano et al (2004), which also suggests low abundances of S, Ar, and Ca (Z/Z e =1-3). We found larger differences between our Chandra results and the Suzaku results by Ono et al (2019), which requires two recombining plasma models with different IGE abundances. This large discrepancy is likely caused by the different spectral extraction regions.…”

Section: Two-temperature Modelcontrasting

confidence: 79%

“…A two-temperature component is needed to fit the spectrum in the 2-8 keV band, as pointed out in previous studies (Sakano et al 2004;Park et al 2005;Koyama et al 2007;Ono et al 2019). We found that an absorbed two-temperature plasma model vvapec+vvapec with abundances tied together well describes the spectrum in the 2-8 keV band and provides a reduced χ 2 (c n 2 ) of 1.45 (dof=381).…”

Section: Two-temperature Modelsupporting

confidence: 70%

“…The combined spectrum of Sgr A East in 2-8 keV shows emission lines of S, Ar, Ca, Fe, and Ni. We confirm that Cr and Mn Heα lines are detected at 5.63 keV and 6.13 keV, respectively (Ono et al 2019). The FeHeα and Lyα lines are also separated using the ACIS-S chips, while the ACIS-I cannot resolve them (see ACIS-I spectra in Park et al 2005).…”

Section: Spectral Analysissupporting

confidence: 70%

“…The elliptical region shown in Figure 1 has a size of 1′×1 5, while the Suzaku spectrum in Ono et al (2019) was selected in a 3 2 diameter region. Due to the larger point-spread function of Suzaku (∼1′ or worse, Ono et al 2019), the Suzaku spectrum of Sgr A East suffers more contamination from background structures such as nonthermal filaments, bright point-like sources, and other irrelevant emission near Sgr A * . n e dt∼n e t for the underionized plasma vvnei model or recombining timescale for the recombining plasma bvvrnei model.…”

Section: Two-temperature Modelmentioning

confidence: 99%

“…Sgr A East has been presumed to result from a core-collapse SN explosion of a <20M e star (Maeda et al 2002;Park et al 2005), although a Type Ia origin has not been ruled out, as Fe is found to be more abundant than IMEs in the remnant (Sakano et al 2004;Park et al 2005). Ono et al (2019) reported Mn and Cr lines from Sgr A East using Suzaku data. Mn and Cr are more frequently observed in thermonuclear SNRs (see Yang et al 2013, and references therein), although they have also been found in the X-ray-luminous corecollapse SNR Cassiopeia A (e.g., Sato et al 2020b).…”

Section: Introductionmentioning

confidence: 99%

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Chemical Abundances in Sgr A East: Evidence for a Type Iax Supernova Remnant

Zhou

Leung

et al. 2021

ApJ

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Recent observations have shown a remarkable diversity of observational behaviors and explosion mechanisms in thermonuclear supernovae (SNe). An emerging class of peculiar thermonuclear SNe, called Type Iax, show photometric and spectroscopic behaviors distinct from normal Type Ia. Their origin remains highly controversial, but pure turbulent deflagration of white dwarfs (WDs) has been regarded as the leading formation theory. The large population of Type Iax indicates the existence of unidentified Galactic Type Iax supernova remnants (SNRs). We report evidence that SNR Sgr A East in the Galactic center resulted from a pure turbulent deflagration of a Chandrasekhar-mass carbon-oxygen WD, an explosion mechanism used for Type Iax SNe. Our X-ray spectroscopic study of Sgr A East using 3Ms of Chandra data shows a low ratio of intermediate-mass elements to Fe and large Mn/Fe and Ni/Fe ratios. This abundance pattern does not accord with the core-collapse or normal Type Ia models. Sgr A East is thus the first Galactic SNR for which a likely Type Iax origin has been proposed and is the nearest target for studying this peculiar class. We compared Sgr A East with the Fe-rich SNRs 3C397 and W49B, which also have high Mn and Cr abundances and were claimed to result from deflagration-to-detonation explosions of Chandrasekhar-mass WDs (although with disputes). Our study shows that they have distinct abundance patterns. The X-ray spectroscopic studies of thermonuclear SNRs provide observational evidence for the theories that there are diverse explosion channels and various metal outputs for Chandrasekharmass WDs.

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Section: Two-temperature Modelcontrasting

confidence: 79%

Section: Two-temperature Modelsupporting

confidence: 70%

Section: Spectral Analysissupporting

confidence: 70%

Section: Two-temperature Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Chemical Abundances in Sgr A East: Evidence for a Type Iax Supernova Remnant

Zhou

Leung

et al. 2021

ApJ

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Hydrodynamic evolution of Sgr A East: the imprint of a supernova remnant in the Galactic Centre

Zhang

Hua

et al. 2023

Monthly Notices of the Royal Astronomical Society

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We perform three-dimensional numerical simulations to study the hydrodynamic evolution of Sgr A East, the only known supernova remnant (SNR) in the center of our Galaxy, to infer its debated progenitor SN type and its potential impact on the Galactic center environment. Three sets of simulations are performed, each of which represents a represent a certain type of SN explosion (SN Iax, SN Ia or core-collapse SN) expanding against a nuclear outflow of hot gas driven by massive stars, whose thermodynamical properties have been well established by previous work and fixed in the simulations. All three simulations can simultaneously roughly reproduce the extent of Sgr A East and the position and morphology of an arc-shaped thermal X-ray feature, known as the “ridge”. Confirming previous work, our simulations show that the ridge is the manifestation of a strong collision between the expanding SN ejecta and the nuclear outflow. The simulation of the core-collapse SN, with an assumed explosion energy of 5 × 1050 erg and an ejecta mass of 10 M⊙, can well match the X-ray flux of the ridge, whereas the simulations of the SN Iax and SN Ia explosions underpredict its X-ray emission, due to a smaller ejecta mass. All three simulations constrain the age of Sgr A East to be ≲1500 yr and predict that the ridge should fade out over the next few hundred years. We address the implications of these results for our understanding of the Galactic center environment.

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Discovery of recombining plasma associated with the candidate supernova remnant G189.6+3.3 with Suzaku

Yamauchi

Oya

Nobukawa

et al. 2020

Publications of the Astronomical Society of Japan

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We present the results of an X-ray spectral analysis of the northeast region of the candidate supernova remnant G189.6+3.3 with Suzaku. K-shell lines from highly ionized Ne, Mg, Si, and S were detected in the spectrum for the first time. In addition, a radiative recombining continuum (RRC) from He-like Si was clearly seen near 2.5 keV. This detection of an RRC reveals for the first time that G189.6+3.3 possesses an X-ray-emitting recombining plasma (RP). The extracted X-ray spectrum in the 0.6–10.0 keV energy band is well fitted with a model consisting of a collisional ionization equilibrium plasma component (associated with the interstellar medium) and an RP component (associated with the ejecta). The spectral feature shows that G189.6+3.3 is most likely to be a middle-aged SNR with an RP.

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X-ray spectra of Sagittarius A East and diffuse X-ray background near the Galactic center

Cited by 11 publications

References 44 publications

Chemical Abundances in Sgr A East: Evidence for a Type Iax Supernova Remnant

Chemical Abundances in Sgr A East: Evidence for a Type Iax Supernova Remnant

Hydrodynamic evolution of Sgr A East: the imprint of a supernova remnant in the Galactic Centre

Discovery of recombining plasma associated with the candidate supernova remnant G189.6+3.3 with Suzaku

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