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تسجيل مستخدم جديدX-ray spectra of Sgr A East and diffuse X-ray background near the Galactic center
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This paper reports the analysis procedure and results of simultaneous spectral fits of the Suzaku archive data for Sagittarius (Sgr) A East and the nearby Galactic center X-ray emission (GCXE). The results are that the mixed-morphology supernova remnant Sgr A East has a recombining plasma (RP) with Cr and Mn He$alpha$ lines, and a power-law component (PL) with an Fe I K$alpha$ line. The nearby GCXE has a $sim$1.5-times larger surface brightness than the mean GCXE far from Sgr A East, although the spectral shape is almost identical. Based on these results, we interpret that the origins of the RP and the PL with the Fe I K$alpha$ line are past big flares of Sgr A$^*$.
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The possible impact Sgr A East is having on the Galactic center has fueled speculation concerning its age and the energetics of the supernova explosion that produced it. We have carried out the first in-depth analysis of the remnants evolution and it
s various interactions: with the stellar winds flowing out from the inner ~2 pc, with the supermassive black hole, Sgr A*, and with the 50 km/s molecular cloud behind and to the East of the nucleus. We have found that a rather standard supernova explosion with energy ~1.5e51 ergs is sufficient to create the remnant we see today, and that the latter is probably only ~1,700 years old. The X-ray Ridge between ~9 and 15 to the NE of Sgr A* appears to be the product of the current interaction between the remaining supernova ejecta and the outflowing winds. Perhaps surprisingly, we have also found that the passage of the remnant across the black hole would have enhanced the accretion rate onto the central object by less than a factor 2. Such a small increase cannot explain the current Fe fluorescence observed from the molecular cloud Sgr B2; this fluorescence would have required an increase in Sgr A*s luminosity by 6 orders of magnitude several hundred years ago. Instead, we have uncovered what appears to be a more plausible scenario for this transient irradiation--the interaction between the expanding remnant and the 50 km/s molecular cloud. The first impact would have occurred about 1,200 years after the explosion, producing a 2-200 keV luminosity of ~1e39 ergs/s. During the intervening 300-400 years, the dissipation of kinetic energy subsided considerably, leading to the much lower luminosity (~1e36 ergs/s at 2-10 keV) we see today.
This paper reports that the X-ray spectrum from the Galactic Center X-ray Emission (GCXE) is expressed by the assembly of active binaries, non-magnetic Cataclysmic Variables, magnetic Cataclysmic Variables (X-ray active star: XAS), cold matter and di
ffuse sources. In the fitting of the limited components of the XASs, the GCXE spectrum exhibits significant excesses with $chi^2/d.o.f. =5.67$. The excesses are found at the energies of K$alpha$, He$alpha$, Ly$alpha$ and radiative recombination continuum of S, Fe and Ni. By adding components of the cold matter and the diffuse sources, the GCXE spectrum is nicely reproduced with $chi^2/d.o.f. = 1.53$, which is a first quantitative model for the origin of the GCXE spectrum. The drastic improvement is mainly due to the recombining plasmas in the diffuse sources, which indicate the presence of high-energy activity of Sgr A$^*$ in the past of $> 1000$~years.
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