Parkes observations for project P1382 semester 2025OCTS_02

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.

银心与银河核球区域内外的毫秒脉冲星（millisecond pulsars, MSPs）的丰度问题，长期以来都是脉冲星天文学的核心研究课题之一。除了因恒星与恒星遗迹密度升高，在银心及银河核球区域内外发现更多奇异且极具研究价值的双星系统之外，MSPs还被提出作为解释观测到的费米伽马射线超出（Fermi gamma-ray excess）的候选体之一。然而迄今为止发现的绝大多数毫秒脉冲星，均为银盘场脉冲星或是球状星团内的毫秒脉冲星。针对银心/银河核球区域MSPs的初步探索，始于在银河丝状结构中发现首批MSPs，但后续的重要进展则来自银心周边毫秒脉冲星样本的发现。针对MSPs的盲巡天观测会受到诸多观测偏差的影响：诸如双星加速度导致的脉冲展宽、高密度区域的散射效应等，这会扩大搜寻的参数空间，有时甚至会令搜寻问题变得难以处理。但若能通过成像巡天可靠地识别脉冲星候选体，那么后续的靶向观测就能让脉冲搜寻问题变得可解。我们对MeerKAT银核球成像巡天中识别出的一批偏振源开展了后续观测，发现了16颗新的毫秒脉冲星。本文申请对其中8颗颇具研究价值的毫秒脉冲星（本发现样本的子集）开展计时观测，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, PTA）研究工作中的潜在应用价值。