arXiv 0709.23642007-09-14astro-ph

寻找类星体的光回波

On the Search for Quasar Light Echoes

Eli Visbal, Rupert A. C. Croft

备注：: 9 pages, 7 figures, ApJ in press
DOI：: 10.1086/523843

摘要：

来自类星体的紫外线辐射在整个周围空间的电离氢分布中留下了特征图案。这种模式或光回波以光速传播通过星系际介质，并且可以通过其在背景源的Ly-alpha森林光谱上的印记来观察。由于回波在类星体关闭后仍然存在，它提供了寻找死亡类星体的可能性，并限制了它们的光度和寿命。我们概述了一种技术来搜索和表征这些光回波。为了测试该方法，我们从z=3的宇宙学模拟中创建人工Ly-alpha森林光谱，应用光回波并搜索它们。我们展示了如何模拟也可以用来量化任何检测的显著性水平。我们发现，从观测数据中可以找到来自最明亮类星体的光回波。在1平方度的区域内，有100个红移z~3-3.5的类星体或星系的吸收线光谱，假设类星体的寿命约为10^7年，我们预计存在约10个来自B波段光度L_B= 3 × 10^45尔格/s的类星体的回波，置信度为95%。即使这样的搜索结果为零，也会对我们理解类星体的光度和寿命产生有趣的影响。

英文摘要：

The UV radiation from a quasar leaves a characteristic pattern in the distribution of ionized hydrogen throughout the surrounding space. This pattern or light echo propagates through the intergalactic medium at the speed of light, and can be observed by its imprint on the Ly-alpha forest spectra of background sources. As the echo persists after the quasar has switched off, it offers the possibility of searching for dead quasars, and constraining their luminosities and lifetimes. We outline a technique to search for and characterize these light echoes. To test the method, we create artificial Ly-alpha forest spectra from cosmological simulations at z=3, apply light echoes and search for them. We show how the simulations can also be used to quantify the significance level of any detection. We find that light echoes from the brightest quasars could be found in observational data. With absorption line spectra of 100 redshift z~3-3.5 quasars or galaxies in a 1 square degree area, we expect that ~10 echoes from quasars with B band luminosities L_B=3x10^45 ergs/s exist that could be found at 95% confidence, assuming a quasar lifetime of ~10^7 yr. Even a null result from such a search would have interesting implications for our understanding of quasar luminosities and lifetimes.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

相关论文