标题： 1H0419-577：一个“双态”软X射线塞弗特星系 显示英文标题

标题： 1H0419-577: A "two-state" soft X-ray Seyfert galaxy

摘要： 在本文中，我们报告了对射电安静活动星系核1H0419-577的首次同时光学和X射线（Beppo-SAX）观测。光学光谱明确使我们将此源分类为塞弗特1型。然而，X射线光谱与此分类有些矛盾：一个简单的平坦（Gamma ~ 1.55）且无特征的幂律能够很好地描述整个1.8-40 keV光谱，尽管对宽铁线的上限不是很严格。对同一目标尚未发表的ROSAT观测的分析显示，软X射线光谱至少在0.7-2 keV波段经历了从陡峭（Gamma ~ 2.5）到平坦（Gamma ~ 1.55）状态的转变。如果这种差异是由于显著变化的软过量，那么单一组分不太可能负责光学/紫外/软X射线光谱分布。讨论了差异是由于主要X射线连续谱的变化的假设及其对当前康普顿化模型的影响。 显示英文摘要

摘要： In this paper we report on the first simultaneous optical and X-ray (Beppo-SAX) observations of the radio-quiet AGN 1H0419-577. The optical spectrum clearly leads us to classify this source as a Seyfert 1. The X-ray spectrum is, however, somewhat at odds with this classification: a simple flat (Gamma ~ 1.55) and featureless power--law is a good description of the whole 1.8-40 keV spectrum, even if the upper limit to a broad iron line is not very tight. An analysis of a still unpublished ROSAT observation of the same target reveals that the soft X-ray spectrum has undergone a transition from a steep (Gamma ~ 2.5) to a flat (Gamma ~ 1.55) state, at least in the 0.7-2 keV band. If this difference is due to a remarkably variable soft excess, it is unlikely that a single component is responsible for the optical/UV/soft X-ray spectral distribution. The hypothesis that the difference is due to a change in the primary X-ray continuum and its implications for current Comptonization models are discussed.