Time-scale-dependent X-ray to UV time lags of NGC 4593 using high-intensity XMM-Newton observations with Swift and AstroSat
Time-scale-dependent X-ray to UV time lags of NGC 4593 using high-intensity XMM-Newton observations with Swift and AstroSat
复制标题
使用 Swift 和 AstroSat 的高强度 XMM-Newton 观测，NGC 4593 与时间尺度相关的 X 射线到 UV 时间滞后
DOI：
10.1093/mnras/stac3391
复制
发表时间：
2023
影响因子：
4.8
通讯作者：
Beard M
中科院分区：
文献类型：
--
作者：
Beard M
我们利用XMM-牛顿方法对NGC 4593进行了140 ks的观测，同时提供了连续的pn X射线和OM UV（UVW 1 2910 nm）光变曲线，比以前的观测更好地采样了短时间尺度的变化。这些观测与先前报道的22 d SwiftX射线和UV/光学监测以及4 d AstroSat软X射线望远镜（SXT），远（FUV 1541 nm）和近（NUV 2632 nm）UV同时进行，允许它们与高采样XMM之间的滞后测量。从XMM中我们发现UVW 1滞后于X射线29.5 ± 1.3ks，是以前从Swift监测中确定的滞后的一半。重新检查的雨燕数据揭示了一个双峰滞后分布，与长期和短期滞后的证据。然而，如果我们用5d宽度的LOWESS滤波来使Swift光变曲线去趋势，则只剩下较短的滞后（23.8 ± 21.2ks）。NUV的观测结果与pn和SXT的观测结果相比较，证实了XMM发现的1030 ks的滞后，而在应用4 d滤波以去除长时间尺度分量之后，FUV显示出1023 ks的滞后。由此产生的新UVW 1、FUV和NUV滞后光谱延伸到X射线波段，而不需要额外的X射线到UV滞后偏移，如果UV来自X射线的再处理，则意味着直接照射再处理器。通过参考以前的Swift和HST lag测量，我们获得了X射线到光学滞后的光谱，这与使用KYN reverb盘再处理代码的模型一致，假设可接受的质量为7.63 × 106 M，自旋接近最大值。以前注意到的滞后贡献的BLR在巴尔末和Paschen连续体仍然突出。
We present a 140 ks observation of NGC 4593 withXMM–Newtonproviding simultaneous and continuous pn X-ray and OM UV (UVW1 2910 Å) light curves, which sample short-time-scale variations better than previous observations. These observations were simultaneous with 22 d ofSwiftX-ray and UV/optical monitoring reported previously, and 4 d ofAstroSat Soft X-ray Telescope(SXT), far (FUV 1541 Å) and near (NUV 2632 Å) UV allowing lag measurements between them and the highly-sampledXMM. From theXMM, we find thatUVW1 lags behind the X-rays by 29.5 ± 1.3 ks, ∼half the lag previously determined from theSwiftmonitoring. Re-examination of theSwiftdata reveals a bimodal lag distribution, with evidence for both the long and short lags. However, if we detrend theSwiftlight curves by LOWESS filtering with a 5 d width, only the shorter lag (23.8 ± 21.2 ks) remains. The NUV observations, compared to pn andSXT, confirm the ∼30 ks lag found byXMM, and after 4 d filtering is applied to remove the long-time-scale component, the FUV shows a lag of ∼23 ks. The resultant newUVW1, FUV, and NUV lag spectrum extends to the X-ray band without requiring additional X-ray to UV lag offset, which if the UV arises from reprocessing of X-rays implies direct illumination of the reprocessor. By referencing previousSwiftandHSTlag measurements, we obtain an X-ray to optical lag spectrum, which agrees with a model using the KYNreverb disc-reprocessing code, assuming the accepted mass of 7.63 × 106M⊙and a spin approaching maximum. Previously noted lag contribution from the BLR in the Balmer and Paschen continua are still prominent.