利用TESS探测耀变体PKS 0422+004的天量级准周期振荡

Detection of Quasiperiodic Oscillation on the Order of Days in Blazar PKS 0422+004 with TESS

摘要: 凌日系外行星巡天卫星(Transiting Exoplanet Survey Satellite, TESS)观测到的耀变体PKS 0422+004(α=04 24 46.8421990080, δ=+00 36 06.329375028)的光学波段光变曲线在第32扇区存在约7.4天的准周期振荡(Quasiperiodic Oscillation, QPO)。使用LSP(Lomb-Scargle Periodogram)方法寻找显著性周期,并用加权小波Z变换(Weight Wavelet Z-transform, WWZ)方法进行时频域分析进一步验证。最后,基于施瓦西黑洞(a=0)和极端克尔黑洞(a=0.998 2)两种模型,估算了这个耀变体中心黑洞的质量。以7.4天为主周期,得到黑洞质量分别为1.11×10⁹M_⊙(施瓦西黑洞)和7.07×10⁹M_⊙(极端克尔黑洞)。

Abstract: We find that the optical band light curve of the blazar PKS 0422+004 observed by the Transiting Exoplanet Survey Satellite (TESS) has a quasiperiodic oscillation (QPO) of about 7.4 days in sector 32. We use the Lomb-Scargle Periodogram (LSP) method to search for significant periods, and further validate them using the Weighted Wavelet Z-transform (WWZ) method for time-frequency domain analysis. Finally, based on Schwarzschild black hole (a=0) and extreme Kerr black hole (a=0.998 2) models, we estimate the mass of the central black hole of this blazar. We obtain black hole masses of 1.11×10⁹M_⊙ (Schwarzschild black hole) and 7.07×10⁹M_⊙ (extreme Kerr black hole) with a main period of 7.4 days.