OGLE 2000-BUL-43: A Spectacular Ongoing Parallax Microlensing Event. Difference Image Analysis
OGLE 2000-BUL-43: A Spectacular Ongoing Parallax Microlensing Event. Difference Image Analysis
复制标题
OGLE 2000-BUL-43：一场壮观的持续视差微透镜事件。
DOI：
--
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
L. Wyrzykowski
中科院分区：
文献类型：
--
作者：
I. Soszyński;K. Żebruń;P. Wozniak;S. Mao;A. Udalski;M. Szymański;M. Kubiak;G. Pietrzyński;O. Szewczyk;L. Wyrzykowski
我们提出了一个隆起微透镜事件OGLE-2000-BUL-43的测光和理论模型。该事件非常明亮，I 0 = 13.54等，并且具有很长的时间尺度，tE = 156天。长的时间尺度和它的光变曲线偏离标准形状强烈表明它可能受到视差效应的影响。我们表明OGLE-2000-BUL-43是第一个发现的微透镜事件，其中在2年内观察到了视差失真。使用Alard &卢普顿的PSF匹配算法的差分图像分析（DIA）使得光度测量精确到0.5%，比标准DoPhot测量提高了4.5倍。DIA获得的所有光度测定都可通过电子方式获得。我们的分析表明，木星附近的观测条件将是最佳的，并可能导致2001年1月31日左右的放大率为1.50。这些功能提供了一个伟大的承诺，解决源（K巨星）和打破退化之间的透镜参数，包括质量的透镜，如果事件是观察与卡西尼号空间探测器上的成像相机。引力微透镜最初是作为一种探测银河系晕中致密暗物质天体的方法提出的（Paczy 'nski 1986）。然而，它也被证明是一种非常有用的方法来研究银河系的结构，恒星的质量函数和潜在的太阳系外行星系统（回顾，见Paczy 'nski 1996）。大多数微透镜事件由标准光变曲线很好地描述（例如，Paczy 'nski 1986）.不幸的是，从这些光变曲线中，我们只能导出一个物理约束，即爱因斯坦半径穿越时间，它涉及到透镜质量、各种距离度量和相对速度（见§4）。这种简并意味着透镜的性质不能被唯一地推断出来。因此，关于透镜配置的任何进一步的信息是非常重要的。表现出松弛效应的微透镜事件提供了这种类型的信息。Refsdal（1966）和Gould（1992）预测了这类事件。第一个案例是由ALGOO合作组织向银河系隆起报告的（Alcock et al. 1995），第二个案例（向船底座）是由OGLE合作组织发现的，并由Mao（1999）报告。在本文中，我们报告了一个新的视差微透镜事件，OGLE-2000-BUL-43。这个隆起事件被早期预警系统（Udalski et al. 1994）提前捕捉到，并因其极端亮度和很长的时间而引起关注。
We present the photometry and theoretical models for a bulge microlensing event OGLE-2000-BUL-43. The event is very bright with I 0 = 13.54 mag, and has a very long time scale, t E = 156 days. The long time scale and its light curve deviation from the standard shape strongly suggest that it may be affected by the parallax effect. We show that OGLE-2000-BUL-43 is the first discovered microlensing event, in which the parallax distortion is observed over a period of 2 years. Difference Image Analysis (DIA) using the PSF matching algorithm of Alard & Lupton enabled photometry accurate to 0.5%, a factor of 4.5 improvement over the standard DoPhot measurements. All photometry obtained with DIA is avaliable electronically. Our analysis indicates that the viewing condition near Jupiter will be optimum and can lead to magnifications ∼ 50 around January 31, 2001. These features offer a great promise for resolving the source (a K giant) and breaking the degeneracy between the lens parameters including the mass of the lens, if the event is observed with the imaging camera on the Cassini space probe. Gravitational microlensing was originally proposed as a method of detecting compact dark matter objects in the Galactic halo (Paczy´nski 1986). However, it also turned out to be an extremely useful method to study Galactic structure, mass functions of stars and potentially extra-solar planetary systems (for a review, see Paczy´nski 1996). Most microlensing events are well described by the standard light curve (e.g., Paczy´nski 1986). Unfortunately, from these light curves, one can only derive a single physical constraint, namely the Einstein radius crossing time, which involves the lens mass, various distance measures and relative velocity (see §4). This degeneracy means that the lens properties cannot be uniquely inferred. Therefore any further information on the lens configuration is of great importance. Microlensing events that exhibit paral-lax effects provide this type of information. Such events were predicted by Refsdal (1966) and Gould (1992). The first case was reported by the MACHO collaboration toward the Galactic bulge (Alcock et al. 1995), and the second case (toward Carina) was discovered by the OGLE collaboration and reported in Mao (1999). In this paper, we report a new parallax microlensing event, OGLE-2000-BUL-43. This bulge event was caught well ahead of the peak by the Early Warning System (Udalski et al. 1994), and attracted attention due to its extreme brightness and a very long time …