Survey for Very Faint Quasars

类恒星物体最引人注目的一点是 （类星体或类星体）是它们强烈的集体演化， 宇宙时间，从近距离和远距离的比较中可以明显看出 样品 类星体发光阶段的持续时间 很短，不到1亿年，因为否则 中心质量会变得不合理的大。 另 一方面，集体进化显然有一个时间尺度， 比十亿年还要长 一个基本的问题， 因此，了解类星体， 出生和死亡，以及什么控制了 类星体的年龄。 如果一个更清晰的画面， 集体进化是可以实现的， 类星体的性质，以及它们与星系起源的关系， 可以更好地理解。 该研究将提供基本的 通过扩展和详细说明一个非常微弱的类星体的数据， 经过验证的测量技术，使其有可能实现 更暗的界限和更高的已确认类星体表面密度 比任何其他调查。调查技术包括 高精度、宽视场、多波段光度测定， 类星体候选者，其次是这些多目标光谱学 候选人获得红移。 目的是确定 低光度类星体的演化特征 很高的红移 这一信息补充了所获得的信息， 对于高亮度类星体的宽视场（施密特）望远镜， 更明亮的极限

One of the most striking aspects of quasi-stellar objects (quasars, or QSOs) is their strong collective evolution with cosmic time, as is apparent from a comparison of near and distant samples. The duration of the luminous phase of quasars is likely to be short, less than 100 million years, because otherwise the central masses would become unreasonably large. On the other hand, the collective evolution evidently has a timescale that is much longer than 1 billion years. A basic question in understanding quasars is thus what governs their individual births and deaths, and what controls the overall activity of quasars over the age of the universe. If a clearer picture for the collective evolution can be obtained, it is possible that the nature of quasars, and their relation to the origin of galaxies, can be better understood. The research will provide fundamental data on very faint quasars by expanding and elaborating on a proven survey technique that has made it possible to achieve fainter limits and a higher surface density of confirmed quasars than any other survey. The survey technique involves high-precision, wide-field, multi-band photometry to identify quasar candidates, followed by multi-object spectroscopy of these candidates to obtain redshifts. The objective is to determine the evolutionary characteristics of low-luminosity quasars up to very high redshifts. This information complements that obtained for high-luminosity quasars by wide-field (Schmidt) telescopes at brighter limits.