X-ray analysis of selected mixed morphology supernova remnants in milk way

A supernova remnant (SNR) is formed as a result of a supernova explosion. A large amount of kinetic energy (10^51 erg) released by the explosion is converted into thermal energy of electrons and atoms by the heating of the shock wave, and this results in the formation of a high-temperature plasma. The ionization equilibrium between electrons and atoms is achieved in 10^(4-5) years, due to the very thin (~1 cm^-3) of this plasma in SNRs. Therefore, X-ray investigations of ionization states of the plasma in SNRs provide a better understanding of the evolutionary stages of the remnants. Moreover, high-temperature plasma in SNRs shows a sum of line emission and continuum emission in their spectrum. Young SNRs often show strong emission lines of heavy elements (eg, O, Mg, Si, S, Ar, Ca, and Fe) remaining from the exploding progenitor. Sensitive measuring of the abundance values of these lines is critical for determining the type of explosion. In this thesis, X-ray analyses of DA 530, CTB 37A, and 3C 391, which are Galactic SNRs with mixed-morphology (MM), were performed. These analyzes aimed to investigate the recombining plasma (RP) in these SNRs. Firstly, the X-ray background of these remnants was calculated. For DA 530, the X-ray background was estimated by removing the vignetting effect, while for CTB 37A and 3C 391 remnants, the X-ray background was excluded with modeling. For the spectral fitting, vvrnei model, which is a spectral model for describing the RP and made available in 2015, was used. vvrnei model was used for the first time for the three SNRs in this thesis. With this model, the age of RP can estimate, which can use to select one of the two origin models of RP, different from the other spectral models. To decide the spectral analysis region of the SNRs, high angular resolution Chandra X-ray Observatory was used. The existence of RP was confirmed for CTB 37A and 3C 391, and the origin of the RP was discussed using the RP age derived from vvrnei spectral model. Subsequently, the physical properties of RP compared with the other SNRs in the literature. For the DA 530, for the first time Suzaku data of this SNR was analyzed, and the estimated physical properties of this SNR were added to the literature (Deniz et al. 2022). According to X-ray analysis, the plasma of DA 530 is not recombining state. Finally, using the best-fit model derived from Suzaku analyzes, next-generation X-ray satellites XRISM/Resolve and Athena/X-IFU simulations performed for three SNRs. With these simulations, the capabilities of XRISM and Athena was measured and thermal emission lines hidden due to poor enough spectral resolution were revealed. Although the DA 530 is a faint SNR in X-rays, it has demonstrated many emission lines with the capabilities of the next generation of X-ray satellites.