The evolution and structure of two interacting supernova remnants (SNRs) are calculated by use of a time-dependent two-dimensional hydrodynamic code. The interactions of two SNRs are simulated in such a way that at a time t0 after the first supernova explosion, the second supernova explosion occurs at the distance D and two SNRs encounter. Two cases are investigated; the second explosion occurs outside or inside the expanding shell of the first SNR. In the first case, the final structures of two interacting SNRs are typically classified into three types: (1) two SNRs merge into a single4ike SNR, (2) two SNRs merge but show a peanut-shape structure, and (3) two SNRs do not merge. In the second case, they reduce to two types: (1) two SNRs evolve as an isolated SNR with twice the explosion energy, and (2) in the shell of the first SNR a bump is formed due to the shock impact by the second explosion. The critical distances for the above structural changes are examined, as well as the changes of the expansion law from an isolated SNR. With these results some discussions are given on the formation of an SNR tunnel system and the possibility of gas ejection from a galaxy. Based upon this view of interacting SNRs, a preliminary model for the solar neighborhood and loop I is presented. Key words: Interstellar matter; Shock waves; Supernova remnants; X-rays.
Publications of the Astronomical Society of Japan
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