Parkes observations for project P1330 semester 2024APRS_04

Millisecond pulsars (MSPs) are created preferentially in globular clusters (GCs), compared to the Galactic disk, due to the large stellar density and the resulting interactions that occur within the clusters. Estimates have tens to hundreds of MSPs within these clusters. Furthermore, the leading hypothesis behind the gamma-ray emission from the GCs, detected by Fermi, is due to cluster MSPs. Thus, we observed three clusters, that were predicted to have tens of MSPs but did not have any detected, and found a highly accelerated binary MSP (NGC6316A) in NGC6316. Finding the first pulsar in a particular globular cluster is always the most challenging part as we have to search over the dispersion measure (DM) as well as period and acceleration. Our chances of finding more pulsars within the cluster have increased now that we know the DM of the cluster. We have a decent constraint on the orbital period of the binary but in order to fully constrain the orbital parameters and determine the type of companion star, we need subsequent observations. These subsequent observations will also be useful to search for more pulsars within the cluster. We are requesting 17 3 hour pointings to solve for the orbit of the binary pulsar and conduct a year-long timing campaign on the pulsar while searching for more pulsars.

毫秒脉冲星（millisecond pulsars, MSPs）相较于银盘，更优先形成于球状星团（globular clusters, GCs）中，这源于星团内极高的恒星密度及其所引发的各类恒星相互作用。当前估算表明，此类星团内部存在数十至数百颗毫秒脉冲星。此外，费米（Fermi）望远镜探测到的球状星团伽马射线辐射，其主流假说认为辐射来源正是星团内的毫秒脉冲星。
为此，我们对三颗此前被预测存在数十颗毫秒脉冲星但尚未有探测结果的球状星团开展了观测，并在NGC 6316星团中发现了一颗高加速度双星毫秒脉冲星NGC 6316A。在特定球状星团中发现首颗脉冲星始终是最具挑战性的工作，因为需要同时对色散量（dispersion measure, DM）、脉冲周期以及加速度进行参数搜索。如今我们已获知该星团的色散量，这提升了在星团内发现更多脉冲星的可能性。目前我们已对该双星系统的轨道周期获得了较为充分的约束，但要完全确定其轨道参数并明确伴星类型，仍需后续观测。此类后续观测同样可用于搜寻该星团内的其他脉冲星。
我们申请开展17次单次时长为3小时的指向观测，以求解该双星脉冲星的轨道参数，并针对该脉冲星开展为期一年的计时观测计划，同时同步搜寻更多脉冲星。