Parkes observations for project P1152 semester 2022APRS_12

A large population of millisecond pulsars (MSPs) is expected in the Galactic bulge and is supported, among others, by the existence of a spatially extended gamma-ray excess emission discovered in Fermi-LAT data towards the inner Galaxy. Discovering MSPs in the Galactic bulge, would be a major breakthrough with strong impact onto several fields. In Berteaud et al. [2021a, 2021b], we have designed a new method to select bulge MSP candidates among Chandra X-ray cataloged sources. We also analysed imaging data of the VLA and identified 5 potential bulge MSP candidates, detected both with Chandra and VLA. Here we propose to follow up these 5 sources with the UWL receiver system on Parkes, which has the unique potential of probe their MSP nature thanks to multi-band, deep, observations. With the requested time, for two high-priority candidates, we will be able identify any bulge MSP with a pulse period P > 1 ms. Three targets at lower priority can be identified as bulge MSP if their period is larger than 4 ms. Our goal is to provide the first multi-wavelength diagnostics of bulge MSPs, gather information about the MSP/pulsar ratio among the bulge X-ray candidates, and, finally, unveil the nature of the mysterious Fermi-LAT excess.

银河系银核区域预计存在大量毫秒脉冲星（millisecond pulsars, MSPs），该推测得到了包括费米大面积望远镜（Fermi-LAT）在银河内侧探测到的空间延展伽马射线超额辐射在内的多项佐证。在银河系银核中发现毫秒脉冲星，将成为一项重大突破，对多个研究领域产生深远影响。在Berteaud等人[2021a, 2021b]的研究中，我们开发了一种全新方法，可从钱德拉X射线望远镜（Chandra）的编目源中筛选银核毫秒脉冲星候选体。我们还对甚长基线阵列（Very Large Array, VLA）的成像数据进行了分析，识别出5个同时被钱德拉和VLA探测到的银核毫秒脉冲星潜在候选体。本研究拟利用帕克斯（Parkes）望远镜的UWL接收机系统对上述5个候选体开展后续观测。该系统凭借多波段深场观测的独特优势，能够验证这些天体的毫秒脉冲星属性。根据申请的观测时长，针对2个高优先级候选体，我们将可识别出脉冲周期P＞1 ms的银核毫秒脉冲星；对于3个低优先级候选体，若其脉冲周期大于4 ms，即可判定为银核毫秒脉冲星。本研究的目标是首次实现银核毫秒脉冲星的多波段诊断，收集银核X射线候选体中毫秒脉冲星与脉冲星的比例信息，并最终揭开费米-LAT伽马射线超额辐射的神秘本质。