Parkes observations for project P1168 semester 2023OCTS_02

We discovered seven pulsars in the globular cluster Terzan 1 with the Green Bank Telescope (GBT), the first pulsars to be found in this cluster. The discoveries include five fully-recycled millisecond pulsars (MSPs) with spin periods between 3 and 6 ms, an 11-ms MSP, and a pulsar with an unusually long spin period of 134 ms. Our preliminary timing suggested that all seven are likely isolated pulsars, consistent with Terzan 1 being a core-collapsed globular cluster. The 134-ms pulsar is an especially interesting discovery in the context of pulsar formation via electron-capture rather than core-collapse supernovae. In 2022OCT we observed Terzan 1 with Parkes three times and confirmed that all pulsars could be detected. We began a year-long timing campaign in the present semester, 2023APR, and were granted continuing status for that campaign. We request to continue timing these pulsars through 2023OCT. To refine the timing parameters and probe the pulsars' acceleration in the cluster potential, we will extend phase connection beyond one year using the 2022OCT observations, and we will attempt to phase connect back to the original GBT discovery pointings. In addition to timing, we will probe the pulsars' polarization properties and the Galactic magnetic field in the direction of Terzan 1; and the proposed observations will also be searched for new pulsars that may have been missed in previous observations.

我们利用绿岸望远镜（Green Bank Telescope, GBT）在球状星团Terzan 1中发现了7颗脉冲星，这是该星团中首次被发现的脉冲星。此次发现的脉冲星包含5颗完全再循环的毫秒脉冲星（MSPs），其自转周期介于3至6毫秒之间，1颗自转周期为11毫秒的毫秒脉冲星，以及1颗自转周期长达134毫秒的特殊脉冲星。我们的初步计时分析显示，这7颗脉冲星均大概率为孤立脉冲星，这与Terzan 1作为核塌缩球状星团的性质相符。其中，这颗134毫秒的脉冲星在通过电子俘获而非核塌超新星形成脉冲星的研究背景下具有尤为重要的研究价值。2022年10月，我们利用帕克斯望远镜（Parkes）对Terzan 1进行了三次观测，确认所有脉冲星均可被探测到。我们于2023年4月启动了为期一年的计时观测项目，并获得了该项目的延续资格，现申请将该计时观测项目延续至2023年10月。为优化计时参数并探究脉冲星在星团引力势中的加速度，我们将利用2022年10月的观测数据将相位连接时长延长至一年以上，同时尝试将相位连接回溯至最初利用绿岸望远镜的发现观测时段。除计时观测外，我们还将对这些脉冲星的偏振特性以及Terzan 1所在天区的银河系磁场进行探测；此外，本次申请的观测计划还将用于搜寻此前观测中可能遗漏的新脉冲星。