Parkes observations for project P1382 semester 2025OCTS_04

The prevalence of millisecond pulsars (MSPs) in and around the Galactic center and the bulge has been one of the key questions in pulsar astronomy. In addition to finding more exotic and interesting binary systems at and around the Galactic center and bulge due to the enhanced density of stars/stellar remnants, MSPs are also proposed to be one of the candidates to explain the observed Fermi gamma-ray excess. However, most of the MSPs discovered so far are field (disk) MSPs or those in globular clusters. Initial steps towards addressing the question of Galactic center/bulge MSPs were made with the discovery of the first MSPs in a Galactic filament, but more progress comes from the discovery of a sample of MSPs around the Galactic center. Blind surveys targeting MSPs can suffer from many observational biases that smear the pulses due to binary acceleration, scattering from the enhanced density, and so on, which increases the parameter space for discovery and can sometimes make the problem intractable. However, if pulsar candidates can be identified reliably from imaging surveys, then targeted observations can make the problem tractable in identifying the pulsations. We followed up a sample of polarized sources identified in the MeerKAT bulge imaging survey and discovered a sample of 16 new MSPs. Here we request the timing observations of 8 interesting MSPs (a subset of our discovery sample), to study the binary nature of these sources and their potential inclusion in pulsar timing array efforts.

毫秒脉冲星（millisecond pulsars, MSPs）在银心及银核周边的分布情况，长期以来都是脉冲星天文学领域的核心研究问题之一。除了因恒星及恒星遗迹密度提升，能够在银心及银核区域发现更多新奇有趣的双星系统之外，毫秒脉冲星还被提出为解释费米伽马射线过量观测现象的候选体之一。不过迄今为止已发现的毫秒脉冲星，绝大多数均为银盘场脉冲星，或是位于球状星团（globular clusters）内的毫秒脉冲星。针对银心/银核毫秒脉冲星问题的初步探索，始于在银河丝状体中发现首批毫秒脉冲星，而后续的关键进展则来自银心周边毫秒脉冲星样本的发现。针对毫秒脉冲星的盲巡天常会受到诸多观测偏差的干扰——比如双星加速度导致的脉冲展宽、高密度环境引发的散射等，这会扩大搜寻所需探索的参数空间，有时甚至会令搜寻任务变得难以推进。不过，若能从成像巡天中可靠识别出脉冲星候选体，通过靶向观测即可让脉冲搜寻问题变得可解。我们对 MeerKAT 银核成像巡天中识别出的一批偏振源开展了后续观测，成功发现了16颗新的毫秒脉冲星。本文申请对其中8颗具有研究价值的毫秒脉冲星（本发现样本的子集）进行计时观测，以研究这些源的双星特性，以及它们在脉冲星计时阵列（pulsar timing array）研究中的潜在应用价值。