标题： JVLA对大质量磁性B型和O型恒星高频射电辐射的调查 显示英文标题

标题： A JVLA survey of the high frequency radio emission of the massive magnetic B- and O-type stars

摘要： 我们使用甚大阵列在1厘米、3厘米和13厘米波段对七颗质量高于$8M_{\odot}$的磁性O型星和十一颗B型星进行了调查。 这次调查发现了两颗O型星和两颗B型星。 虽然被检测到的O型星——HD 37742和HD 47129——处于双星系统中，但被检测到的B型星HD 156424和ALS 9522目前未被发现处于双星系统中。 这四颗恒星都在3厘米波段被检测到，而三颗在1厘米波段被检测到，仅有一颗在13厘米波段被检测到。 被检测到的B型星的射电光度明显高于未被检测到的B型星，而O型星则没有这种情况。 13厘米波段的未检测结果被解释为热自由-自由吸收所致。 通过3厘米波段的流量密度估算质量损失率，并与理论质量损失率进行比较，理论假设为自由-自由辐射。 对于HD 37742，质量损失率的两个值吻合良好，可能表明该恒星的射电辐射主要是热辐射。 对于其他三颗恒星，从射电观测估算的质量损失率远高于理论预期，这可能表明磁星可能存在非热辐射的贡献，或由于双星系统的相互作用风导致的热辐射或非热辐射，尤其是HD 47129。 所有被检测到的恒星都被预测拥有离心磁层，除了HD 37742，它可能拥有动力学磁层。 这表明在具有离心磁层的恒星中，非热射电辐射更受青睐。 显示英文摘要

摘要： We conducted a survey of seven magnetic O and eleven B-type stars with masses above $8M_{\odot}$ using the Very Large Array in the 1cm, 3cm and 13cm bands. The survey resulted in a detection of two O and two B-type stars. While the detected O-type stars - HD 37742 and HD 47129 - are in binary systems, the detected B-type stars, HD 156424 and ALS 9522, are not known to be in binaries. All four stars were detected at 3cm, whereas three were detected at 1cm and only one star was detected at 13cm. The detected B-type stars are significantly more radio luminous than the non-detected ones, which is not the case for O-type stars. The non-detections at 13cm are interpreted as due to thermal free-free absorption. Mass-loss rates were estimated using 3cm flux densities and were compared with theoretical mass-loss rates, which assume free-free emission. For HD 37742, the two values of the mass-loss rates were in good agreement, possibly suggesting that the radio emission for this star is mainly thermal. For the other three stars, the estimated mass-loss rates from radio observations were much higher than those expected from theory, suggesting either a possible contribution from non- thermal emission from the magnetic star or thermal or non-thermal emission due to interacting winds of the binary system, especially for HD 47129. All the detected stars are predicted to host centrifugal magnetospheres except HD 37742, which is likely to host a dynamical magnetosphere. This suggests that non-thermal radio emission is favoured in stars with centrifugal magnetospheres.