In a failed supernova, partial ejection of the progenitor’s outer envelope can occur due to weakening of the core’s gravity by neutrino emission in the protoneutron star phase. We consider emission when this ejecta sweeps up the circumstellar material, analogous to supernova remnants (SNRs). We focus on failed explosions of blue supergiants, and find that the emission can be bright in soft X-rays. Due to its soft emission, we find that sources in the Large Magellanic Cloud (LMC) are more promising for detection than those in the Galactic disk. These remnants are characteristic in their small size (≲10 pc) and slow speed (100s of km s−1) compared to typical SNRs. Although the expected number of detectable sources is small (up to a few by the eROSITA four-year all-sky survey), prospects are better for deeper surveys targeting the LMC. Detection of these “failed SNRs” will realize observational studies of mass ejection following black hole formation.

中文翻译：

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失败的超新星遗迹

在失败的超新星中，由于质子中子星阶段的中微子发射削弱了核心的引力，可能会发生前身外层的部分喷射。当这种喷射物扫过星际物质时，我们考虑发射，类似于超新星遗迹 (SNR)。我们关注蓝超巨星的失败爆炸，发现发射在软 X 射线中可能很亮。由于其软发射，我们发现大麦哲伦星云 (LMC) 中的源比银盘中的源更有希望被检测到。与典型的 SNR 相比，这些残余物的特征在于其体积小 (≲10 pc) 和慢速 (100s of km s−1)。尽管预期的可探测源数量很少（根据 eROSITA 为期四年的全天调查，最多只有几个），但针对 LMC 的更深入调查的前景更好。