论文标题
关于从AGN的光学到NIR变化时间延迟中测量哈勃常数的可能性
On the possibility for measuring the Hubble constant from optical-to-NIR variability time delay in AGNs
论文作者
论文摘要
已经报告了少数AGN（大约7个）的光学边红色可变性时间延迟，并且仅针对其中5个被牢固地建立。时间延迟可能随着IR波长的增加而增加。最自然的这段时间延迟可以通过模型来解释，即IR发射归因于核辐射加热的核糖灰尘。在给定的模型中，关于近红外（NIR）发射区域狭窄的建议是很自然的，只要无法在距离远距离距离距离灰尘靠近的距离之外，而不是一些临界值，该临界值可以达到石墨颗粒的升华温度（Barvainis，1987）。对于NGC 4151的情况，已显示NIR区具有薄环或圆环的形式。该环的半径与核活性的水平相关（Oknyanskij等，1999）。 NIR发射区域从光度的这种依赖性揭示了自身在对象变异性下（如NGC4151的情况下），并且当考虑到具有较高和低亮度的对象时。我们假设观察到的时间延迟使我们能够得出一个红移独立的光度距离，并估算一个哈勃常数。 讨论了将这种策略用于哈勃恒定确定的一些问题。
The Optical-to-Near-infrared variability time delay have already been reported for a small number (about 7) of AGNs and has been firmly established only for 5 of them. The time delay is probably increasing with the IR wavelengths. The most naturally this time delay can be interpreted by the model where IR emission is attributed to circumnuclear dust heated by the nuclear radiation. In given model a suggestion on narrowness of the near-infrared (NIR) emission region is quite natural, as far as the dust can be not saved on distances from the nucleus closer then some critical value, on which it is reached the sublimation temperature for graphite particles (Barvainis, 1987). For NGC 4151 case it has been shown that the NIR region has a form of thin ring or torus. The radius of this ring correlates with level of the nucleus activity (Oknyanskij et al. 1999). This dependency of radius of the NIR emission region from luminosity reveals itself as under object variability (as in the case of NGC4151), and also when objects with high and low luminosity are considered. We assume that the observed time delays allow us to derive a redshift independent luminosity distances to AGNs and estimate a Hubble constant. Some problems of using this strategy for the Hubble constant determination are discussed.
