Title: A high-density relativistic reflection origin for the soft and hard X-ray excess emission from Mrk 1044 Show Chinese title

Title: Mrk 1044软X射线和硬X射线过量辐射的高密度相对论性反射起源

Abstract: We present the first results from a detailed spectral-timing analysis of a long ($\sim$130 ks) XMM-Newton observation and quasi-simultaneous NuSTAR and Swift observations of the highly-accreting narrow-line Seyfert 1 galaxy Mrk 1044. The broadband (0.3$-$50 keV) spectrum reveals the presence of a strong soft X-ray excess emission below $\sim$1.5 keV, iron K$_{\alpha}$ emission complex at $\sim$6$-$7 keV and a `Compton hump' at $\sim$15$-$30 keV. We find that the relativistic reflection from a high-density accretion disc with a broken power-law emissivity profile can simultaneously explain the soft X-ray excess, highly-ionized broad iron line and the Compton hump. At low frequencies ($[2-6]\times10^{-5}$ Hz), the power-law continuum dominated 1.5$-$5 keV band lags behind the reflection dominated 0.3$-$1 keV band, which is explained with a combination of propagation fluctuation and Comptonization processes, while at higher frequencies ($[1-2]\times10^{-4}$ Hz), we detect a soft lag which is interpreted as a signature of X-ray reverberation from the accretion disc. The fractional root-mean-squared (rms) variability of the source decreases with energy and is well described by two variable components: a less variable relativistic disc reflection and a more variable direct coronal emission. Our combined spectral-timing analyses suggest that the observed broadband X-ray variability of Mrk 1044 is mainly driven by variations in the location or geometry of the optically thin, hot corona. Show Chinese abstract

Abstract: 我们介绍了对高吸积率窄线 Seyfert 1 星系 Mrk 1044 的一次长时间（$\sim$130 ks）XMM-Newton 观测以及准同时的 NuSTAR 和 Swift 观测进行详细光谱定时分析的首次结果。 宽频（0.3$-$50 keV）谱显示在$\sim$1.5 keV以下存在强烈的软X射线过量辐射，铁K$_{\alpha}$发射复合体在$\sim$6$-$7 keV处以及在$\sim$15$-$30 keV处的“康普顿驼峰”。 我们发现，高密度吸积盘的相对论性反射，具有分段幂律发射率轮廓，可以同时解释软X射线过量、高度电离的宽铁线和康普顿驼峰。 在低频（$[2-6]\times10^{-5}$Hz）时，幂律连续谱在1.5$-$5 keV波段滞后于反射主导的0.3$-$1 keV波段，这被解释为传播波动和康普顿化过程的结合，而在较高频率（$[1-2]\times10^{-4}$Hz）时，我们检测到一个软滞后，这被解释为吸积盘X射线回响的特征。 源的分数均方根（rms）变异性随能量而减少，并且由两个可变成分很好地描述：一个变化较小的相对论性盘反射和一个变化较大的直接冕发射。 我们结合的光谱-时变分析表明，Mrk 1044观测到的宽频X射线变异性主要由光学薄、热冕的位置或几何结构的变化驱动。