中德$λ$银河面6厘米偏振巡天VI超新星遗迹G178.2 - 4.2和G25.1 - 2.3的发现
A Sino-German $λ$6\ cm polarization survey of the Galactic plane VI. Discovery of supernova remnants G178.2-4.2 and G25.1-2.3
摘要：
超新星遗迹（SNRs）经常在银河平面的无线电调查中被发现。由于先前的调查的表面亮度限制，更多的微弱或混乱的SNR等待发现。中德$λ$ 6厘米银道面巡天是一项灵敏的巡天，有可能探测到新的低表面亮度信噪比。我们希望从银河平面的$λ$ 6\cm测量图中识别新的SNR。我们在$λ$ 6\cm巡天图中寻找新的贝壳状天体，并使用$λ$ 6\cm图以及$λ$ 11\cm和$λ$ 21\cm Effelsberg观测结果研究了它们的射电发射、偏振和光谱。具有非热光谱的扩展偏振物体被识别为SNR。我们已经发现了两个新的，大的，微弱的SNRs，G178.2 - 4.2和G25.1 - 2.3，这两个都显示出壳结构。G178.2 - 4.2的大小为72 arcmin x 62 arcmin，沿其北部外壳检测到强烈的偏振发射。G178.2 - 4.2的光谱是非热的，其积分光谱指数为$α= -0.48\pm0.13$。它的表面亮度是$Σ_{1 GHz} = 7.2 x 10^{-23}{Wm^{-2} Hz^{-1} sr^{-1}}$，这使得G178.2 - 4.2成为已知的第二个最暗的银河系信噪比。G25.1 - 2.3是由其强大的南部外壳显示，其大小为80 arcmin x 30 \arcmin。它有一个非热射电频谱，频谱指数为$α= -0.49\pm0.13$。在银道面2200 ° ^2的区域内，在$λ$ 6 cm处探测到了两个新的大壳型信噪比。这表明存在更大和更微弱的SNR，但很难检测到。
英文摘要：
Supernova remnants (SNRs) were often discovered in radio surveys of the Galactic plane. Because of the surface-brightness limit of previous surveys, more faint or confused SNRs await discovery. The Sino-German $λ$6\ cm Galactic plane survey is a sensitive survey with the potential to detect new low surface-brightness SNRs. We want to identify new SNRs from the $λ$6\ cm survey map of the Galactic plane. We searched for new shell-like objects in the $λ$6\ cm survey maps, and studied their radio emission, polarization, and spectra using the $λ$6\ cm maps together with the $λ$11\ cm and $λ$21\ cm Effelsberg observations. Extended polarized objects with non-thermal spectra were identified as SNRs. We have discovered two new, large, faint SNRs, G178.2-4.2 and G25.1-2.3, both of which show shell structure. G178.2-4.2 has a size of 72 arcmin x 62 arcmin with strongly polarized emission being detected along its northern shell. The spectrum of G178.2-4.2 is non-thermal, with an integrated spectral index of $α= -0.48\pm0.13$. Its surface brightness is $Σ_{1 GHz} = 7.2 x 10^{-23}{Wm^{-2} Hz^{-1} sr^{-1}}$, which makes G178.2-4.2 the second faintest known Galactic SNR. G25.1-2.3 is revealed by its strong southern shell which has a size of 80 arcmin x 30\arcmin. It has a non-thermal radio spectrum with a spectral index of $α= -0.49\pm0.13$. Two new large shell-type SNRs have been detected at $λ$6\ cm in an area of 2200 deg^2 along the the Galactic plane. This demonstrates that more large and faint SNRs exist, but are very difficult to detect.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
