论文标题

MAVERIC调查:由银河球形簇Terzan的深度无线电连续观测揭示的新紧凑型二进制文件5

The MAVERIC Survey: New compact binaries revealed by deep radio continuum observations of the Galactic globular cluster Terzan 5

论文作者

Urquhart, Ryan, Bahramian, Arash, Strader, Jay, Chomiuk, Laura, Ransom, Scott M., Wang, Yuankun, Heinke, Craig O., Tudor, Vlad, Miller-Jones, James C. A., Tetarenko, Alexandra J., Maccarone, Thomas J., Sivakoff, Gregory R., Shishkovsky, Laura, Swihart, Samuel J., Tremou, Evangelia

论文摘要

由于其庞大的密集核心,Terzan 5具有在银河球状簇中众所周知的毫秒脉冲星人群。在这里,我们报告了新的$ 2-8 \,$ GHz无线电连续观测Terzan \,5,使用Karl G. Jansky获得的非常大的阵列获得。我们已经确定了群集半径半径内的24个来源,其中包括核心半径内的17个。 19与先前研究的毫秒脉冲星和X射线二进制文件有关。三个新的无线电源具有陡峭的无线电光谱,并且位于集群核心内,如毫秒脉冲星所预期。这三个来源具有硬X射线光子指数($γ= 1.3-1.5 $)和高度可变的X射线发射,这表明它们是属于蜘蛛等级的二进制毫秒脉冲星。对于这些来源中最X射线发光的最X射线,红带蜘蛛的分类通过其X射线光曲线确认,该曲线显示出12.32小时的轨道周期,并且在X射线最大值附近的双峰结构。像Terzan 5这样经过深思熟虑的集群中,可能发现明亮的二进制毫秒脉冲星,突出了无线电连续成像如何可以补充脉冲星搜索和定时观察结果,以找到可能的黯然失色的系统。核心中的另一个新无线电源具有平坦的无线电频谱,并且X射线微弱($ L_X \大约2 \ times 10^{31} $ ERG S $^{ - 1} $)具有光子索引$γ= 2.1 \ pm0.5 $,与Quiescent Stellar-Mass Blackhole-Mass Blackhole x-ray x-ray x-ray x-ray x-ray x-ray x-ray x-ray x-ray x-ray x-ray x-ray x-pm0.5 $一致。

Owing to its massive, dense core, Terzan 5 has the richest population of millisecond pulsars known among Galactic globular clusters. Here we report new deep $2-8\,$GHz radio continuum observations of Terzan\,5 obtained with the Karl G. Jansky Very Large Array. We have identified a total of 24 sources within the cluster half-light radius, including 17 within the core radius. 19 are associated with previously studied millisecond pulsars and X-ray binaries. Three of the new radio sources have steep radio spectra and are located within the cluster core, as expected for millisecond pulsars. These three sources have hard X-ray photon indices ($Γ=1.3-1.5$) and highly variable X-ray emission, suggesting they are binary millisecond pulsars belonging to the spider class. For the most X-ray luminous of these sources, the redback spider classification is confirmed by its X-ray light curve, which shows an orbital period of 12.32 hr and double peaked structure around X-ray maximum. The likely discovery of bright binary millisecond pulsars in a well-studied cluster like Terzan 5 highlights how deep radio continuum imaging can complement pulsar search and timing observations in finding probable eclipsing systems. The other new radio source in the core has a flat radio spectrum and is X-ray faint ($L_X \approx 2\times 10^{31}$ erg s$^{-1}$) with a photon index $Γ=2.1\pm0.5$, consistent with the properties expected for a quiescent stellar-mass black hole X-ray binary.

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