Parkes observations for project P1313 semester 2024APRS_04

Pulsars orbiting high-mass stellar companions provide a novel means of directly probing the space weather of these comparatively uncommon stars. PSR J1638-4725 is one such binary system for which little has been published to date. It displays an extraordinary amount of variability in its detected radio emission, which could be used to answer fundamental questions about the nature of the companion star and the intra-binary environment. This includes: What is the exact nature of the companion star? What does the circumbinary environment in this system look like? And can we use this system as a Galactic fast radio burst analogue? Obtaining answers to these questions with existing data sets is challenging, as the variable pulsar properties make it extremely difficulty to obtain a coherent timing solution across several orbits of the system. In order to address this problem, we request a set of high-cadence observations of PSR J1638-4725 with the Ultra-Wideband Low (UWL) receiver system. This will allow us to obtain an initial timing solution, from which we can re-derive the orbital properties of the system and begin answering the above questions.

环绕大质量恒星伴星运行的脉冲星，为直接探测这类相对罕见恒星的空间天气提供了全新的研究路径。PSR J1638-4725便是此类双星系统之一，截至目前相关公开研究成果极为有限。该系统的射电辐射探测信号呈现极强的变异性，这一特性可用于解答有关伴星本质与双星内部环境的一系列基础科学问题。这些问题具体包括：伴星的确切物理本质为何？该系统的双星周围环境呈现何种特征？以及我们能否将该系统作为银河系内快速射电暴的类比研究对象？利用现有数据集解答上述问题颇具挑战性，由于脉冲星的多变属性，在该系统的多个轨道周期内获取连贯计时解变得极为困难。为解决这一难题，我们申请使用超宽带低（Ultra-Wideband Low, UWL）接收机系统，对PSR J1638-4725开展一组高频次观测。此次观测将助力我们获取初始连贯计时解，借此重新推导该系统的轨道参数，并着手解答前述科学问题。