论文标题
银河核中的SuperStoft，发光的X射线源
Supersoft, luminous X-ray sources in galactic nuclei
论文作者
论文摘要
潮汐破坏事件（TDE）通常在X射线或光波长中通过其瞬时性质发现。 X射线检测到的TDE的特征光谱特征是“超级” X射线发射，在任何其他外乳层面的源中都没有观察到，但少数几种，快速变化的高可变X射线源（HLXS）或SuperSoft farsoft Active Galactic核（AGN）可通过其光学优化而区分。我们工作的目的是找到与银河系中心相关的超植物超材。我们预计该类别将包括被忽视的TDE，SuperSoft AGN和核HLXS。寻找这种来源将允许研究不同黑洞质量尺度上的极端状态积聚。我们通过互相关的光学和X射线目录搜索了SuperSoft X射线源（SSS），以选择近核近核来源，然后我们过滤了非常陡峭的光谱（光子指数$γ> 3 $）和高X射线仪式和高X射线仪（$ l_x> 10^> 10^{41} $ l_x> 10^{41} $ eRG〜ERG〜ERG〜ERG〜S $} $} $} $} $} $} $} $} - 1} - 1} - 1} - 1} - 1} - {^ - 1} - { - {^ - {^ - 1} { - { - 1} - { - 1} { - { - { - { - 1}。通过盲目搜索，我们检索了大约60个来源，包括15个先前已知的SuperSoft AGN或TDE，因此证明了我们选择的效率。在其余样品中，尽管显示出比平常的光谱较陡的，但被光学地分类为AGN。其余的九个以前未知的来源显示出与极端柔软的主导AGN（五个来源）或TDE（四个来源）发射一致的光谱特性。 {\ it xmm-newton}这些来源之一的后续观察证实了其可能的tde性质。我们的工作是第一次通过其光谱特征发现TDE的尝试，而不是它们的可变性，并且已经成功地检索已知的TDE并发现了新的ExtremulSoft来源，其中包括四个新的TDE候选者，其中一种是通过后续观察确认的。
Tidal disruption events (TDEs) are usually discovered at X-ray or optical wavelengths through their transient nature. A characteristic spectral feature of X-ray detected TDEs is a "supersoft" X-ray emission, not observed in any other extragalactic source, with the exception of a few, rapidly variable hyper-luminous X-ray sources (HLXs) or supersoft active galactic nuclei (AGN) that are however distinguishable by their optical emission. The goal of our work is to find extragalactic supersoft sources associated with galactic centres. We expect this category to include overlooked TDEs, supersoft AGN and nuclear HLXs. Finding such sources would allow for the study of extreme regime accretion on different black hole mass scales. We searched for supersoft X-ray sources (SSS) by cross-correlating optical and X-ray catalogues to select extragalactic near-nuclear sources and we then filtered for very steep spectra (photon index $Γ>3$) and high X-ray luminosities ($L_X>10^{41}$~erg~s$^{-1}$). With our blind search, we retrieved about 60 sources including 15 previously known supersoft AGN or TDEs, so demonstrating the efficiency of our selection. Of the remaining sample, 36 sources, although showing steeper-than-usual spectra, are optically classified as AGN. The remaining nine, previously unknown sources show spectral properties consistent with the emission by extremely soft-excess dominated AGN (five sources) or TDE (four sources). An {\it XMM-Newton} follow-up observation of one of these sources confirmed its likely TDE nature. Our work is the first attempt to discover TDEs by their spectral features rather than their variability and has been successful in retrieving known TDEs as well as discovering new extreme ultrasoft sources, including four new TDE candidates, one of which is confirmed via follow-up observations.
