在半人马座47中通过连续谱搜索发现一个新的可能的脉冲星双星
A new likely pulsar binary in 47~Tucanae from continuum searches
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中文总结 AI 辅助
研究通过多方面观测，发现长期被误认的半人马座47 W41实际是红背脉冲星双星，它有特定X射线强度、光子指数，呈微弱陡谱射电连续谱源，还有椭球调制等特征，其位置和轨道周期有助于未来匹配新射电脉冲星，揭示紧密脉冲星双星易被误分类。
中文摘要 AI 辅助
我们提供证据表明，长期以来被认为是由日冕活动驱动的X射线源半人马座47 W41实际上是一个红背脉冲星双星。该源持续显示出\(L_X = 3 \times 10^{31}\)尔格每秒（0.5 - 10 keV），远超宁静态活动双星的日冕饱和极限，但与红背脉冲星中观测到的双星内激波一致，其光子指数\(\Gamma = 1.4\pm0.1\)也是如此。此外，利用澳大利亚望远镜紧凑阵列的深度数据，我们表明W41是一个微弱的（5.5 GHz时为\(9.8\pm1.4 \mu\)Jy）陡谱（\(\alpha = -1.8\pm0.4\)）射电连续谱源，这符合脉冲星的预期。哈勃空间望远镜测光的光变曲线建模显示存在椭球调制，一个约\(0.5\) - \(0.55 M_{\odot}\)的次星围绕一个不可见伴星受到轻微辐照，这也与红背解释一致。W41的精确位置及其精确测量的10.4小时轨道周期，应能使其在未来数据中与新发现的射电脉冲星匹配。我们的结果表明，即使在像半人马座47这样研究充分的星团中，紧密脉冲星双星仍隐藏在活动双星中被错误分类。
英文摘要
We present evidence that the X-ray source 47~Tuc~W41, long considered to be an X-ray source powered by coronal activity, is actually a redback pulsar binary. The source continually shows $L_X = 3 \times 10^{31}$ erg s$^{-1}$ (0.5--10 keV), which is well in excess of the coronal saturation limit for active binaries in quiescence, but is consistent with the intrabinary shock observed in redback pulsars, as is its photon index of $Γ= 1.4\pm0.1$. In addition, using deep data from the Australia Telescope Compact Array, we show that W41 is a faint ($9.8\pm1.4 μ$Jy at 5.5 GHz) steep spectrum ($α= -1.8\pm0.4$) radio continuum source, as expected for a pulsar. Light curve modelling of Hubble Space Telescope photometry shows evidence for ellipsoidal modulation with mild irradiation of a $\sim 0.5$--$0.55 M_{\odot}$ secondary around an invisible companion, also consistent with the redback interpretation. The precise position of W41, along with its well-measured 10.4-hr orbital period, should enable it to be matched to a newly-discovered radio pulsar in future data. Our result shows that close pulsar binaries are still hiding, misclassified among active binaries, even in well-studied clusters like 47 Tuc.
