Variable Heating and Flaring of Three Redback Millisecond Pulsar Companions
Variable Heating and Flaring of Three Redback Millisecond Pulsar Companions
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DOI：
10.3847/1538-4357/aade92
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发表时间：
2018-10-10
影响因子：
4.9
通讯作者：
Bogdanov, Slavko
中科院分区：
文献类型：
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作者：
Cho, Patricia B.;Halpern, Jules P.;Bogdanov, Slavko
我们在时间序列测光中监测已建立和假定的红背毫秒星（MSP），重复覆盖它们的5-6。r'或R中的hr轨道光变曲线。在月的时间尺度上，PSR J1048+2339和XMMU J083850.38-282756.8在伴星星星的加热侧表现出近似0.3等的相似变化。然而，加热光变曲线很少是对称的，这表明脉冲星风产生的双星内激波除了是可变的之外，还是偏斜的，或者是伴随脉冲星风的固有磁场变化。除了这种可变的加热，还有长寿命的耀斑状态，增加了额外的0.5等的亮度，在大约10分钟的时间尺度上的变化。这些耀斑似乎也起源于伴星的加热侧，而“夜晚”侧的亮度保持相对稳定。PSR J1628-3205的光学光变曲线以潮汐畸变（椭球调制）为主，但它也显示出由于磁场移动或星星斑点迁移而导致的可变和不对称加热的证据。这些影响挫败了从红背MSP的光学光变曲线导出系统参数（诸如倾斜角和罗氏瓣填充因子）的任何努力。我们还报告了PSR J1048+2339的两个钱德拉X射线观测结果，它们显示出强烈的轨道调制，可能是由于沿着双星内激波的光束，以及第三个观测结果主要是耀斑。在0.3-8 keV波段的耀斑峰值亮度约为脉冲星自旋下降功率的12%，这可能需要磁场重联。这三个系统都还没有显示出过渡回吸积状态。
We monitor established and putative redback millisecond pulsars (MSPs) in time-series photometry, repeatedly covering their 5-6. hr orbital light curves in r' or R. On timescales of months, PSR J1048+2339 and XMMU J083850.38-282756.8 exhibit similar variability of approximate to 0.3 mag on the heated side of the companion star. However, the heating light curve is rarely symmetric, suggesting that the intrabinary shock generated by the pulsar wind is skewed in addition to being variable, or that changing magnetic fields intrinsic to the companion channel the pulsar wind. In addition to this variable heating, there are long-lived flaring states that increase the brightness by an additional 0.5 mag, with variability on approximate to 10 min timescales. These flares also appear to originate on the heated side of the companion, while the "night"-side brightness remains relatively stable. Somewhat less active, PSR J1628-3205 has an optical light curve that is dominated by tidal distortion (ellipsoidal modulation), although it too shows evidence of variable and asymmetric heating due to shifting magnetic fields or migrating star spots. These effects frustrate any effort to derive system parameters such as inclination angle and Roche-lobe filling factor from optical light curves of redback MSPs. We also report on two Chandra X-ray observations of PSR J1048+2339 that show strong orbital modulation, possibly due to beaming along the intrabinary shock, and a third observation that is dominated by flaring. The peak flare luminosity in the 0.3-8 keV band is approximate to 12% of the pulsar's spin-down power, which may require magnetic reconnection. None of these three systems has yet shown a transition back to an accreting state.