Parkes observations for project P986 semester 2018OCTS_02

Pulsar survey is one of the top priorities of the Square Kilometer Arrays (SKA). The discovery of pulsars in relativistic binaries, pulsars in binary with black holes and pulsars in the Galactic Center (GC) will improve our understanding of gravity theories, physics of black holes and stellar population and environment in the GC region. However, conventional periodic searches for pulsars are only sensitive to strictly periodic signals with low duty cycles. Although various methods have been developed to search for pulsars in these extreme systems, it is still very challenging and computationally expensive. \r\n\r\nOne of the solutions is to find pulsar candidates in radio continuum surveys and then carry out targeted searches (e.g. Frail et al 2017). This technique allows a search over the full field of view while avoiding the need for expensive pixel-by-pixel high time resolution searches. We propose to observe 32 compact, steep spectrum candidates selected from NVSS and TGSS surveys using the Ultra-Wideband Low (UWL) receiver. The frequency coverage (as low as 700MHz) and low system temperature (~20K) of UWL will enable us to carry out a sensitive search of steep spectrum sources.

脉冲星巡天（Pulsar survey）是平方公里阵列（Square Kilometer Arrays, SKA）的核心优先任务之一。在相对论性双星系统中的脉冲星、与黑洞组成双星的脉冲星，以及银心（Galactic Center, GC）区域内的脉冲星的发现，将助力我们深化对引力理论、黑洞物理以及银心区域恒星种群与环境的认知。然而，传统的脉冲星周期性搜索仅对低占空比的严格周期性信号敏感。尽管已开发出多种方法用于搜索这类极端系统中的脉冲星，但该任务仍极具挑战性且计算成本高昂。

一种可行的解决方案是先从射电连续谱巡天中筛选出脉冲星候选体，随后开展靶向搜索（例如Frail等人2017）。该技术可实现全视场搜索，同时无需进行成本高昂的逐像素高时间分辨率搜索。我们提议使用超宽带低（Ultra-Wideband Low, UWL）接收机，对从NVSS与TGSS巡天中选取的32个致密陡谱候选体开展观测。超宽带低接收机的频率覆盖范围（低至700MHz）和约20K的低系统温度，将使我们能够对陡谱源开展高灵敏度搜索。