论文标题
银河核中轻度偏心不稳定传质的准周期喷发
Quasi-periodic eruptions from mildly eccentric unstable mass transfer in galactic nuclei
论文作者
论文摘要
我们提出，最近观察到的银河核中的准周期性喷发（QPE）是由于低质量主序列的Roche Lobe溢出而导致的不稳定的质量转移产生的。我们认为QPE发射是由圆形冲击供电的，而不是直接由黑洞积聚。我们的模型预测存在比时间平均QPE亮度更明亮的时态积聚磁盘，但主要在极端UV中排放。这与在Erosita QPE1，QPE2和GSN 069中检测到的静态软X射线发射一致。这种增生磁盘具有不寻常的$b_νl_ν\ propto c n {12/7} $ optical Spectrum。明亮QPE相的寿命为100 - 1000年，是由大量损失设置的，该质量是由恒星和恒星本身喂养的积聚磁盘之间的RAM压接相互作用触发的。 We show that the stellar orbits needed to explain QPEs can be efficiently created by the Hills breakup of tight stellar binaries provided that (i) the stellar binary orbit is tidally hardened before the breakup due to diffusive growth of the f-mode amplitude, and (ii) the captured star's orbit decays by gravitational wave emission without significant orbital angular momentum diffusion (which is the case for black holes less than大约一百万msun）。最后，我们通过讨论模型对超速恒星的含义，极端质量比灵感，重复的部分TDE和银河系核中相关的恒星现象。
We propose that the recently observed quasi-periodic eruptions (QPEs) in galactic nuclei are produced by unstable mass transfer due to Roche lobe overflow of a low-mass main-sequence star in a mildly eccentric (e ~ 0.5) orbit. We argue that the QPE emission is powered by circularization shocks, but not directly by black hole accretion. Our model predicts the presence of a time-steady accretion disk that is bolometrically brighter than the time-averaged QPE luminosity, but primarily emits in the extreme-UV. This is consistent with the quiescent soft X-ray emission detected in between the eruptions in eROSITA QPE1, QPE2, and GSN 069. Such accretion disks have an unusual $νL_ν\propto ν^{12/7}$ optical spectrum. The lifetime of the bright QPE phase, 100-1000 yrs, is set by mass-loss triggered by ram-pressure interaction between the star and the accretion disk fed by the star itself. We show that the stellar orbits needed to explain QPEs can be efficiently created by the Hills breakup of tight stellar binaries provided that (i) the stellar binary orbit is tidally hardened before the breakup due to diffusive growth of the f-mode amplitude, and (ii) the captured star's orbit decays by gravitational wave emission without significant orbital angular momentum diffusion (which is the case for black holes less than about a million Msun). We conclude by discussing the implications of our model for hyper-velocity stars, extreme mass ratio inspirals, repeating partial TDEs, and related stellar phenomena in galactic nuclei.
