We present spectroscopic and photometric monitoring of NGC 3783 conducted throughout the first half of 2020. Time delays between the continuum variations and the response of the broad optical emission lines were clearly detected, and we report reverberation measurements for H$\beta$, HeII $\lambda 4686$, H$\gamma$, and H$\delta$. From the time delay in the broad H$\beta$ emission line and the line width in the variable portion of the spectrum, we derive a black hole mass of $M_{\rm BH} = 2.34^{+0.43}_{-0.43} \times 10^7$ M$_{\odot}$. This is slightly smaller than, but consistent with, previous determinations. However, our significantly improved time sampling ($T_{\rm med}=1.7$ days compared to $T_{\rm med}=4.0$ days) has reduced the uncertainties on both the time delay and the derived mass by $\sim 50$%. We also detect clear velocity-resolved time delays across the broad H$\beta$ profile, with shorter lags in the line wings and a longer lag in the line core. Future modeling of the full velocity-resolved time delay response will further improve the reverberation-based mass for NGC 3783, adding it to the small but growing sample of AGNs for which we have direct, primary black hole mass measurements. Upcoming MUSE observations at VLT will also allow NGC 3783 to join the smaller sample of black holes where reverberation masses and masses from stellar dynamical modeling may be directly compared.

中文翻译：

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南赛弗特 NGC 3783 的机器人混响映射

我们展示了 2020 年上半年对 NGC 3783 进行的光谱和光度监测。清楚地检测到连续谱变化与宽光发射线响应之间的时间延迟，我们报告了 H$\beta$、HeII $ 的混响测量\lambda 4686$、H$\gamma$ 和 H$\delta$。从宽 H$\beta$ 发射线的时间延迟和光谱可变部分的线宽，我们推导出黑洞质量 $M_{\rm BH} = 2.34^{+0.43}_{- 0.43} \times 10^7$ M$_{\odot}$。这比之前的决定略小，但与之前的决定一致。然而，我们显着改进的时间采样（$T_{\rm med}=1.7$ 天与 $T_{\rm med}=4.0$ 天相比）已经将时间延迟和导出质量的不确定性降低了 $\sim 50 美元%。我们还在广泛的 H$\beta$ 剖面上检测到清晰的速度分辨时间延迟，线翼中的滞后较短，线芯中的滞后较长。未来对全速度分辨时间延迟响应的建模将进一步改善 NGC 3783 基于混响的质量，将其添加到我们有直接、主要黑洞质量测量的小但不断增长的 AGN 样本中。即将在 VLT 进行的 MUSE 观测还将允许 NGC 3783 加入较小的黑洞样本，在那里可以直接比较混响质量和来自恒星动力学建模的质量。将它添加到我们有直接、主要黑洞质量测量的 AGN 样本中。即将在 VLT 进行的 MUSE 观测还将允许 NGC 3783 加入较小的黑洞样本，在那里可以直接比较混响质量和来自恒星动力学建模的质量。将它添加到我们有直接、主要黑洞质量测量的 AGN 样本中。即将在 VLT 进行的 MUSE 观测还将允许 NGC 3783 加入较小的黑洞样本，在那里可以直接比较混响质量和来自恒星动力学建模的质量。