2010年-2011年BL Lacertae光学波段的观测与研究

发布时间：2018-03-20 13:44

本文选题：BL　切入点：Lac　出处：《清华大学》2013年硕士论文　论文类型：学位论文

【摘要】：我们在2010年的九月、十月和十一月以及2011年的九月和十月，利用清华大学—国家天文台80cm望远镜（TNT），对BL Lacertae进行了总共16天的BVRI光学多波段观测。从光变曲线上可以看出，BL Lacertae在长时标以及短时标上都有明显的变化。在2010年的三次观测过程中，BL Lacertae相对平静，每天的光变幅度在0.1个星等左右，而每次观测的平均亮度先变亮约0.2mag又变暗约0.3mag。而2011年的两次观测中则非常活跃，相比2010年同一时间段，BL Lacertae变亮了1mag；其中2011年9月的光变尤为突出，光变模式多样，尤其是在2011年9月20日晚，目标在R波段经历了一次幅度为0.3mag的爆发，这是整个观测中光变最大的一次，而且每晚之间平均星等的变化也非常明显。2011年10月5日观测到了一次快速的光变过程，在不到1小时内变化了0.1mag。从光变曲线上可以看出，各波段的光变联系紧密，，但也会有明显的时间延迟现象。为了研究不同波段之间光变的时间延迟，我们选取了进行密集拍摄的3天的B波段和R波段的观测结果，利用离散相关函数的方法进行分析，结果表明，其中有2天这两个波段没有明显的延迟关系，而另外一天，即在2010年11月2日，B波段的光变要比R波段延迟约1000秒左右，即发生了硬延迟。这种硬延迟对于BL Lacertae来说是比较罕见的，这表明喷流中电子的加速与冷却可能经历了与平常不同的物理过程。结合高能电子加速与冷却时标，我们估算出辐射区域磁场强度为5.2G。在色指数分析中，目标在短时标内都会随光度的增大而变硬，但在长时标上，色指数比较平坦。我们的研究结果表明，属于中等能量峰的BL Lacertae在光学波段的光变形式与高能峰的BL Lac天体在X射线波段的光变形式非常相似，这种相似性暗示前者的光学波段光变与后者的X射线波段光变很有可能是来自于黑洞的同一区域，即喷流中相对论电子所产生的同步辐射中最高能的那一部分。
[Abstract]:On September, October and November of #datee and November and November of 2011, we have made a BVRI optical multiband observation of BL Lacertae for a total of 16 days by using the 80cm Telescope of Tsinghua University and National Astronomical Observatory. From the light variation curve, we can see that there are obvious changes in both the long time scale and the short time scale. During the three observations on 2010, BL Lacertae is relatively quiet, and the range of light variation is about 0.1 magnitude per day. The average brightness of each observation was about 0.2mag and then darkened about 0.3mag.However, the two observations in 2011 were very active, and the brightness of BL Lacertae was 1magg compared with that of 2010 at the same time. The light change in September 2011 was especially prominent, and the mode of light variation was various. Especially on the night of September 20th 2011, the target experienced an explosion of 0.3 mag in R band, which was the largest light change in the whole observation. And the change in the average magnitude is also evident every night. In October 5th 2011, a rapid light change was observed, with a change of 0.1 mags in less than an hour. From the optical curve, we can see that each band is closely connected, but there is also obvious time delay phenomenon. In order to study the time delay of light change between different bands, We selected the observations of B-band and R-band for three days of intensive shooting and analyzed them by using the discrete correlation function method. The results show that there is no obvious delay relationship between the two bands for two days, and the other day, In November 2nd 2010, the optical transition of B band was delayed by about 1000 seconds than that of R band, that is, the hard delay occurred. This hard delay is rare for BL Lacertae. This suggests that the acceleration and cooling of electrons in the jet may undergo a different physical process than usual. Combined with the high energy electron acceleration and cooling time scale, we estimate that the intensity of the magnetic field in the radiation region is 5.2 G. in the color index analysis, The target will become hard with the increase of luminosity in the short time scale, but the color index is flat on the long time scale. Our results show that the optical variation form of BL Lacertae in optical band is very similar to that of BL Lac object with high energy peak in X ray band. This similarity suggests that the optical band light variation of the former and the X-ray band light change of the latter are probably from the same region of the black hole, that is, the part of the maximum energy of synchrotron radiation produced by relativistic electrons in the jet.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P157.7

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