引力透镜效应在星系结构研究中的应用

发布时间：2018-04-09 10:06

本文选题：引力透镜效应　切入点：恒星质量　出处：《清华大学》2011年博士论文

【摘要】：引力透镜效应是广义相对论的一个重要结论，，在天体物理研究中有着广泛的应用。我们通过蒙特卡洛模拟研究了以银河系内恒星或恒星遗迹（白矮星，中子星，黑洞）为透镜天体的类星体微引力透镜效应，给出了光变时标，全天区的光深和不同视星等极限下的事例率。我们的模拟计算表明，Pan-STARRS和LSST每年将观测到大约10个类星体微引力透镜事例，典型的光变时标约为1个月。类星体作为宇宙学距离上的一类点源天体，它们的距离远大于河内透镜天体的距离，这使得类星体微引力透镜事例中参数兼并情况变得有所缓和，使得利用类星体微引力透镜效应测量透镜天体的质量成为可能。根据Gaia的设计性能，Gaia卫星将会精确地测量大量的明亮恒星的三角视差和自行。我们的计算表明每年将会有1个恒星可以通过类星体微引力透镜效应得到它的质量。这种方法无需恒星处在一个双星系统中，是与模型无关的，它使得精确测定单个恒星级天体的质量成为可能。中等引力透镜效应的强度介于强引力透镜效应和弱引力透镜效应之间，它的放大倍数约为1.5，不产生多像。我们研究了中等引力透镜效应下背景椭圆星系的光深，并基于LSST的观测能力模拟生成了背景椭圆星系在中等引力透镜效应下的成像。通过IRAF ELLIPSE对成像等亮度曲线的分析，我们发现椭圆星系的的等亮度曲线存在明显的扭曲。由于透镜星系的放大作用，背景椭圆星系的有效半径变大，而有效半径内的平均视亮度不变，从而导致椭圆星系的偏离了原来的基本面。此外，我们通过对背景椭圆星系成像的逆向拟合处理，很好地得到了背景椭圆星系deVaucouleurs面亮度轮廓的参数和SIS透镜星系模型下的爱因斯坦环的角半径。如果能测得透镜星系和背景椭圆星系的红移，通过拟合给出爱因斯坦环角半径，我们就可以得出透镜星系速度弥散，进而可以估计透镜星系的总质量。
[Abstract]:Gravitational lensing effect is an important conclusion of general relativity and has been widely used in astrophysics.By Monte Carlo simulation, we study the quasar microgravitational lensing effects of stars or stellar remnants (white dwarfs, neutron stars, black holes) as lens objects in the Milky way Milky way.The depth of light in the whole sky region and the occurrence rate at the limit of different visual stars.Our simulations show that Pan-STARRS and LSST will observe about 10 quasar microgravitational lensing events each year, with a typical phototropic time scale of about one month.As a kind of point source object in cosmological distance, quasars are far more distant than Hanoi lens objects, which makes the merger of parameters in quasar microgravitational lens case more moderate.It is possible to use quasar microgravitational lens effect to measure the mass of lens objects.According to Gaia's design performance, the Gaia satellite will accurately measure the triangular parallax and motion of a large number of bright stars.Our calculations show that one star per year will be able to get its mass through the quasar microgravitational lens effect.This method, which does not require stars to be in a binary system, is model-independent and makes it possible to accurately measure the mass of a single star class celestial body.The strength of the moderate gravitational lensing effect is between the strong gravitational lensing effect and the weak gravitational lensing effect, and its magnification is about 1.5, and no multi-image is produced.We study the light depth of background elliptical galaxies under the medium gravitational lensing effect and generate the imaging of the background elliptic galaxies under the medium gravitational lensing effect based on the simulation of LSST's observability.Through IRAF ELLIPSE's analysis of the imaging isointensity curve, we find that there is a significant distortion in the elliptical galaxy's isobrightness curve.Due to the magnification of lens galaxies, the effective radius of the background elliptical galaxies becomes larger, while the average apparent brightness within the effective radius remains unchanged, which leads to the departure of the elliptical galaxies from the original fundamentals.In addition, the parameters of the luminance profile of the background elliptic galaxy deVaucouleurs plane and the angular radius of the Einstein ring under the SIS lens galactic model are obtained by the inverse fitting of the background elliptical galaxy imaging.If the redshift of the lens galaxy and the background elliptical galaxy can be measured, the velocity dispersion of the lens galaxy can be obtained by fitting the angular radius of the Einstein ring, and then the total mass of the lens galaxy can be estimated.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2011
【分类号】：P14

【相似文献】