HST imaging of four gravitationally lensed quasars
HST imaging of four gravitationally lensed quasars
复制标题
DOI：
10.1093/mnras/sty1793
复制
发表时间：
2018-07
影响因子：
4.8
通讯作者：
N. Bate;G. Vernardos;M. O’Dowd;D. Neri-Larios;R. Webster;D. Floyd;R. Barone-Nugent;K. Labrie-
中科院分区：
文献类型：
--
作者：
N. Bate;G. Vernardos;M. O’Dowd;D. Neri-Larios;R. Webster;D. Floyd;R. Barone-Nugent;K. Labrie-
我们提出了新的哈勃空间望远镜WFC 3成像的四个引力透镜类星体：MG 0414+0534; RXJ 0911+0551; B 1422+231; WFI J2026-4536。在其中三个系统中，我们检测到波长相关的微透镜，我们用它来限制每个类星体中吸积盘的大小和温度分布。假设吸积盘半径根据与λ（p）成比例的幂律关系r随波长变化，相当于T与r（-1/p）成比例的径向温度分布。这项工作的目标是寻找偏离标准薄盘理论，该理论预测半径与波长的幂p = 4/3。我们发现幂律指数范围很广，从B 1422+ 231中的p = 1.4（-0.4）（+0.5）到WFI J2026-4536中的p = 2.3（-0.4）（+0.5）。p的测量值似乎与波长相关的微透镜的强度相关。我们探讨这个问题与模拟模拟使用一个固定的吸积盘与p = 1.5，并发现波长相关的微透镜是小的情况下，往往会低估p的值。这使人怀疑以前的合奏单历元的测量，有利于低价值使用样本的透镜类星体，显示只有适度的色效应。仅使用我们的具有强色微透镜的系统，我们倾向于p>4/3，对应于比标准薄盘理论预期的更浅的温度分布。
We present new Hubble Space Telescope WFC3 imaging of four gravitationally lensed quasars: MG 0414+0534; RXJ 0911+0551; B 1422+231; WFI J2026-4536. In three of these systems we detect wavelength-dependent microlensing, which we use to place constraints on the sizes and temperature profiles of the accretion discs in each quasar. Accretion disc radius is assumed to vary with wavelength according to the power-law relationship r proportional to lambda(p), equivalent to a radial temperature profile of T proportional to r(-1/p). The goal of this work is to search for deviations from standard thin disc theory, which predicts that radius goes as wavelength to the power p = 4/3. We find a wide range of power-law indices, from p = 1.4(-0.4)(+0.5) in B 1422+231to p = 2.3(-0.4)(+0.5) in WFI J2026-4536. The measured value of p appears to correlate with the strength of the wavelength-dependent microlensing. We explore this issue with mock simulations using a fixed accretion disc with p = 1.5, and find that cases where wavelength-dependent microlensing is small tend to underestimate the value of p. This casts doubt on previous ensemble single-epoch measurements which have favoured low values using samples of lensed quasars that display only moderate chromatic effects. Using only our systems with strong chromatic microlensing we prefer p>4/3, corresponding to shallower temperature profiles than expected from standard thin disc theory.