An estimate of the Hubble constant from the gravitational lensing of quasar Q0957+561
An estimate of the Hubble constant from the gravitational lensing of quasar Q0957+561
复制标题
根据类星体 Q0957 561 引力透镜对哈勃常数的估计
作者：
G. Rhee
双类星体Q0957+561 AB被认为是由红移z = 0.36的星系形成的引力透镜图像：由于中间星系的介入，z = 1.41的单个类星体被看作是两个图像。我在这里给出了一个对介入星系的速度色散的测量，结合对两幅图像中亮度变化出现之间的时间延迟的测量，可以应用于透镜几何的一个简单模型，以产生哈勃常数H0的估计。两组对A和B图像的通量进行了数年的监测，得出A和B变化之间的时间延迟一致为415天。测量到的星系的视线速度色散为303±50 km s−11，得到H0 = 50±17 km s−1 Mpc−1。
THE double quasar Q0957+561 AB is believed to be a gravitationally lensed image formed by a galaxy at redshift z = 0.36: a single quasar at z = 1.41 is seen as two images because of the intevening galaxy. I present here a measurement of the velocity dispersion of the intevening galaxy which, combined with a measurement of the time delay between the appearance of brightness variations in the two images, can be applied to a simple model of the lensing geometry to yield an estimate for the Hubble constant H0. The flux from the A and B images has been monitored for several years by two groups and a consistent value of 415 days for the time delay between variations in A and B has been obtained. The measured line-of-sight velocity dispersion for the intervening galaxy of 303±50 km s−11 then gives H0 = 50±17 km s−1 Mpc−1.