标题： G76.9+1.0中的中心点源 显示英文标题

标题： The central point source in G76.9+1.0

摘要： 我们描述了在超新星遗迹(SNR) G76.9+1.0的618 MHz图像中偶然发现的一个射电点源。该SNR具有双极结构，该点源位于连接两个发射叶的微弱发射桥附近。该点源也在后续更高频率(1170 MHz)的观测中被检测到。从GMRT观测中获得的该点源的光谱指数为alpha = -2.1。陡峭的光谱以及该点源靠近SNR中心的位置证实了它确实是与该SNR相关的脉冲星J2022+3842。与此一致，对存档钱德拉X射线数据的后续分析显示了一个与射电点源重合的点源，以及围绕未分辨源的弥漫扩展X射线辐射。然而，在610 MHz和1160 MHz进行了深入搜索，但未检测到脉冲辐射，尽管在2 GHz时使用GBT已经观察到了脉冲辐射。看起来，未能在GMRT检测到脉冲信号的最可能原因是时间展宽：对于该SNR的估计DM，脉冲展宽时间可能高达几十毫秒。弥漫的X射线辐射沿着与射电中观察到的双极结构相同的方向延伸。我们将射电叶解释为由赤道风形成。尽管尚未能直接检测到脉冲信号，但我们明确展示了在多个频率上进行灵敏、高分辨率的射电成像是一种寻找脉冲星候选者的有效方法。 显示英文摘要

摘要： We describe the serendipitous discovery of a radio point source in a 618 MHz image of the supernova remnant(SNR) G76.9+1.0. The SNR has a bipolar structure and the point source is located near a faint bridge of emission joining the two lobes of emission. The point source was also detected in follow-up higher frequency(1170 MHz) observations. The spectral index for the point source obtained from the GMRT observations is alpha = -2.1. The steep spectrum, as well as the location of the point source near the centre of the SNR establish the fact that it is indeed the pulsar J2022+3842 associated with this SNR. Consistent with this, subsequent analysis of archival Chandra X-ray data shows a point source coincident with the radio point source, as well as diffuse extended X-ray emission surrounding the unresolved source. However, no pulsed emission was detected despite deep searches at both 610 MHz and 1160 MHz although pulsed emission has been seen at 2 GHz with the GBT. It appears that the most likely reason for not detecting the pulsed signal at the GMRT is temporal broadening: for the estimated DM towards this SNR, the pulse broadening time could be as large as tens of milliseconds. The diffuse X-ray emission is elongated along the same direction as the bipolar structure seen in the radio. We interpret the radio lobes as having been formed from an equatorial wind. Although direct detection of pulsed signal has not been possible, we show convincingly that sensitive, high-resolution, radio imaging at multiple frequencies is a useful method to search for pulsar candidates.