论文标题
矮人AGN NGC 4395的光学变异性来自过渡系外行星卫星
Optical Variability of the Dwarf AGN NGC 4395 from the Transiting Exoplanet Survey Satellite
论文作者
论文摘要
我们介绍了来自附近Galaxy NGC 4395中的原型矮人活性银河核（AGN）的传播系外行星调查卫星（TESS）的光曲线。在达到背景噪声水平之前的数周到数小时，在时间尺度上检测到显着的差异。 $ \ sim $一个月的30分钟，高精度苔丝光曲线可以通过简单的潮湿随机步行（DRW）型号非常适合，而潮湿的时间表$τ_{\ rm drw} $被约束在$ 2.3 _ _ {-0.7}^{-0.7}^{+1.8}^{+1.8} $ 〜Days（$1σ$）。 NGC 4395几乎完全在于$τ_ {\ rm drw} -m _ {\ rm bh} $关系的$τ_ {\ rm drw} -m _ {\ rm drm bh} $的关系，该关系是针对BH质量的AGN测量的，该AGN质量大于三个数量级以上。具有高频斜率（$ -1.88 \ pm0.15 $）的断开功率定律可以很好地适应光学可变性周期图（$ -1.88 \ pm0.15 $）和特征时间表（$τ_{\ rm br} \ equiv 1/（2πf_ {\ rm br}）在1 $σ$之内。这项工作证明了苔丝光曲线在识别具有光学变异性的低质量smbhs方面的力量，以及潜在的全局$τ_ {\ rm drw} -m _ {\ rm bh} $的关系，可用于估算具有光学可变性测量的SMBH群众。
We present optical light curves from the Transiting Exoplanet Survey Satellite (TESS) for the archetypical dwarf active galactic nucleus (AGN) in the nearby galaxy NGC 4395 hosting a $\sim 10^5\,M_\odot$ supermassive black hole (SMBH). Significant variability is detected on timescales from weeks to hours before reaching the background noise level. The $\sim$month-long, 30 minute-cadence, high-precision TESS light curve can be well fit by a simple damped random walk (DRW) model, with the damping timescale $τ_{\rm DRW}$ constrained to be $2.3_{-0.7}^{+1.8}$~days ($1σ$). NGC 4395 lies almost exactly on the extrapolation of the $τ_{\rm DRW}-M_{\rm BH}$ relation measured for AGNs with BH masses that are more than three orders of magnitude larger. The optical variability periodogram can be well fit by a broken power law with the high-frequency slope ($-1.88\pm0.15$) and the characteristic timescale ($τ_{\rm br}\equiv 1/(2πf_{\rm br})=1.4_{-0.5}^{+1.9}\,$days) consistent with the DRW model within 1$σ$. This work demonstrates the power of TESS light curves in identifying low-mass accreting SMBHs with optical variability, and a potential global $τ_{\rm DRW}-M_{\rm BH}$ relation that can be used to estimate SMBH masses with optical variability measurements.
