Searching for pulsars associated with polarised point sources using LOFAR: Initial discoveries from the TULIPP project
Searching for pulsars associated with polarised point sources using LOFAR: Initial discoveries from the TULIPP project
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使用 LOFAR 搜索与偏振点源相关的脉冲星：TULIPP 项目的初步发现
DOI：
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发表时间：
2022
期刊：
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通讯作者：
A. Karastergiou
中科院分区：
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作者：
C. Sobey;C. Bassa;S. O’Sullivan;J. Callingham;C. Tan;J. Hessels;V. Kondratiev;B. Stappers;C. Tiburzi;G. Heald;T. Shimwell;R. Breton;M. Kirwan;H. Vedantham;E. Carretti;J. Grießmeier;M. Haverkorn;A. Karastergiou
发现射电双星，特别是毫秒双星（MSP），对于一系列天体物理学应用非常重要，例如测试重力理论或探测磁离子星际介质。我们的目标是通过利用低频阵列（LOFAR）两米巡天（LoTSS）中敏感的低频无线电图像中已知的脉冲星观测值（主要是偏振）来发现可能在以前的脉冲星搜索中错过的脉冲星，并已开始使用LoTSS图像进行有针对性的搜索，用于偏振脉冲星（TULIPP）调查。对于这项调查，我们确定了在LoTSS图像中通量密度大于2 mJy的线性和圆偏振点源，中心频率为144 MHz，带宽为48 MHz。超过40个已知的卫星，其中一半是MSP，在LoTSS图像中被检测为极化源，并从调查中排除。我们已经获得了波束形成的LOFAR观测的30个候选人，这是搜索脉动使用相干去色散。在这里，我们介绍了TULIPP调查第一年的结果。我们发现了两颗恒星，PSR J1049+5822和J1602+3901，旋转周期分别为P=0.73 s和3.7 ms。我们还检测到另外五个已知的双星（两个缓慢旋转的双星和三个MSP），其准确的天空位置无法与LoTSS源进行唯一的交叉匹配。这种有针对性的调查提出了一种相对有效的方法，通过这种方法，可以使用诸如平方公里阵列及其寻路器/先驱物等敏感射电望远镜的灵活观测模式来发现射电星，特别是MSP，特别是因为使用相干去色散的广域全天空调查目前在计算上是不可行的。
Discovering radio pulsars, particularly millisecond pulsars (MSPs), is important for a range of astrophysical applications, such as testing theories of gravity or probing the magneto-ionic interstellar medium. We aim to discover pulsars that may have been missed in previous pulsar searches by leveraging known pulsar observables (primarily polarisation) in the sensitive, low-frequency radio images from the Low-Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS), and have commenced the Targeted search, using LoTSS images, for polarised pulsars (TULIPP) survey. For this survey, we identified linearly and circularly polarised point sources with flux densities brighter than 2 mJy in LoTSS images at a centre frequency of 144 MHz with a 48 MHz bandwidth. Over 40 known pulsars, half of which are MSPs, were detected as polarised sources in the LoTSS images and excluded from the survey. We have obtained beam-formed LOFAR observations of 30 candidates, which were searched for pulsations using coherent de-dispersion. Here, we present the results of the first year of the TULIPP survey. We discovered two pulsars, PSRs J1049+5822 and J1602+3901, with rotational periods of P=0.73 s and 3.7 ms, respectively. We also detected a further five known pulsars (two slowly-rotating pulsars and three MSPs) for which accurate sky positions were not available to allow a unique cross-match with LoTSS sources. This targeted survey presents a relatively efficient method by which pulsars, particularly MSPs, may be discovered using the flexible observing modes of sensitive radio telescopes such as the Square Kilometre Array and its pathfinders/precursors, particularly since wide-area all-sky surveys using coherent de-dispersion are currently computationally infeasible.