AI 中文总结
本研究在VLASS与RACS中搜寻到108个射电发射型猎犬座RS型变星候选体，发现部分系统射电光度极高，且两颗光学明亮的该类变星可产生与宁静黑洞双星相当的持续明亮射电信号，提示两类天体存在误认可能。
AI 中文摘要
我们从国际变星索引（VSX）星表中选取猎犬座RS型（RS CVn）双星，在甚大天线阵天空巡天（VLASS；三个观测历元）和快速ASKAP连续谱巡天（RACS；两个观测历元）数据中开展了射电辐射的系统搜寻。我们在至少一个历元中探测到108个候选射电发射型RS CVn，其中数个系统位列迄今报道的最具射电光度的RS CVn双星之列。通过与eROSITA和ROSAT X射线星表交叉匹配得到的射电与X射线光度，符合磁活动恒星的Güdel-Benz关系，但也可与射电明亮的宁静黑洞X射线双星相媲美，表明这两类天体存在误认的可能性。对光学、射电及恒星特性的分析显示，光学明亮的RS CVn（即至少含一个巨星分量的系统）射电较暗，且其周期与较低的日冕活动一致。然而，其中两个光学明亮的RS CVn系统在所有观测历元中均呈现出持续且异常高的射电比光度（>2×10¹⁷ erg/s/Hz），表明恒星活动可产生与宁静黑洞双星相当的相对持续的明亮射电信号。
英文摘要
We performed a systematic search for radio emission from RS Canum Venaticorum (RS CVn) binaries, selected from the International Variable Star Index (VSX) catalog, in the Very Large Array Sky Survey (VLASS; three epochs) and Rapid ASKAP Continuum Survey (RACS; two epochs) data. We detected 108 candidate radio-emitting RS CVn in at least one epoch. Several of these systems rank among the most radio-luminous RS CVn binaries reported to date. The radio and X-ray luminosities, obtained from cross-matching with the eROSITA and ROSAT X-ray catalogs, are consistent with the Guedel-Benz relation for magnetically active stars, but are also comparable to radio-luminous quiescent black hole X-ray binaries, indicating a potential for misidentification between these two classes. Analysis of optical, radio, and stellar properties indicates that optically bright RS CVn (i.e., those with at least one giant component) are radio-quieter and have periods that are consistent with lower coronal activity. However, two of these optically bright RS CVn systems show persistent and unusually high radio specific luminosities (>2e17 erg/s/Hz) across all observed epochs, showing that stellar activity can produce relatively persistent radio signals as bright as quiescent black hole binaries.
Comments26 pages, 12 figures, 2 MRT tables (Tables 2 & 3), Accepted for publication in ApJ
