AT 2016blu：发光蓝变星与致密天体双星中的吸积驱动爆发
AT 2016blu: Accretion-Powered Outbursts in a Luminous Blue Variable and Compact Object Binary
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中文总结 AI 辅助
研究发现NGC 4559星系的伪超新星AT 2016blu的27次准周期爆发由LBV与致密天体双星的吸积驱动，为首个此类大质量X射线双星案例
中文摘要 AI 辅助
我们首次在NGC 4559星系中探测到超新星（SN） impostor（伪超新星）AT 2016blu的X射线信号。AT 2016blu在2012年至2026年6月间出现了27次被探测到的准周期（约113天）爆发，推测由偏心双星系统的近星点通过触发，该系统的主星是质量大于33倍太阳质量（$33~M_{\rm \u2299}$）的发光蓝变星（LBV）。AT 2016blu在2001-2002年被钱德拉（Chandra）偶然观测到，早于2012年首次记录的爆发，但叠加的存档数据未探测到X射线信号。我们在源的预测爆发时间附近监测其可见光波段变异性，并于2026年3月触发钱德拉的目标机会观测计划，在五个相邻的历元获得了探测结果。这些数据显示X射线光度为$\boldsymbol{\rm log} L_{\rm X} \u2248 38.64 \u00b1 0.11$ erg s$^{-1}$，吸积率$\boldsymbol{\rm \u1e66} M \u2273 8 \times 10^{-8}~M_{\rm \u2299}~\rm yr^{-1}$，与存在致密伴星的情况一致。因此我们得出结论，AT 2016blu是已知的首例LBV型伪超新星，其爆发由间歇性吸积到致密天体驱动。该系统由大质量恒星和致密伴星组成，属于大质量X射线双星，与SN 2010da类似，不过SN 2010da的供体星是红超巨星。
英文摘要
We present the first X-ray detection of the supernova (SN) impostor AT 2016blu in NGC 4559. AT 2016blu exhibited 27 detected quasiperiodic (~113 day) outbursts between 2012 and June 2026, presumably triggered by periastron passages in an eccentric binary system in which the primary is a $\gtrsim 33~M_{\odot}$ luminous blue variable (LBV). AT 2016blu was serendipitously observed by Chandra in 2001-2002, prior to its first documented outburst in 2012, but the stacked archival data show no X-ray detection. We monitored the source's visual-wavelength variability around its predicted outburst time and triggered a Chandra Target of Opportunity program in March 2026, obtaining observations with detections over five closely spaced epochs. These data indicate an X-ray luminosity of $\log L_{\rm X} \approx 38.64 \pm 0.11$~erg~s$^{-1}$ and an accretion rate of $\dot{M} \gtrsim 8\times10^{-8}~M_{\odot}~\mathrm{yr^{-1}}$, consistent with the presence of a compact companion. We therefore conclude that AT 2016blu is the first known case of an LBV SN impostor whose outbursts are driven by intermittent accretion onto a compact object. Given that the system consists of a massive star and a compact companion, AT 2016blu is a high-mass X-ray binary, similar to SN 2010da, although the donor star in SN 2010da is a red supergiant.
