热尘埃遮蔽星系在中低红移的性质和演化

Hot dust-obscured galaxies (Hot DOGs) has been newly discovered by NASA’s wide-field infrared survey explorer (WISE). They are a new type of galaxies which are among the most luminous galaxies in the universe, and they are experiencing a special evolution stage, which is crucial in the theory of galaxy evolution. The principle applicant of this proposal is a key member in discovering Hot DOGs, and is leading a few key projects to the follow-up study of this new population. ..We found that the internal reason for the extremely high luminosity of Hot DOGs is that their embedded super massive black holes are experiencing a very high rate accretion, and they may be a good representative of a type of galaxies hosting super massive black holes who are accreting at their maximum level, with some properties similar to those z~6 quasars. Although Hot DOGs are found most at z=2-3, this type of high-accreting embedded quasars could exist in every cosmic time. We propose in this program to take advantage of advanced facilities in China or in the world through both existing collaborations from PI and NOAC-based international collaborating programs, using the successful experience from how we selected z=2-3 Hot DOGs from WISE, to select a new sample of Hot DOGs at lower redshifts (z=0.5-1.5), and study their properties and evolution. This effort will also enable higher resolution study of these embedded highly accreting supper massive black holes for the first time. We also propose to use the support from this program to take some further study on known z>2 Hot DOGs. This program, once funded and completed, will generate good impact on the study of galaxy evolution and supper massive black hole accretion.

热尘埃遮蔽星系（Hot DOGs)是由WISE天文卫星新近发现的一种处于特殊演化阶段的宇宙中光度最大的星系，对研究星系演化具有非常重要的意义。申请人为发现这一类星系的核心成员，正在领导多个对这类星系的关键后续研究。我们发现Hot DOGs星系极高光度的本质在于其含有的超大质量黑洞正处在极高吸积率状态，可能代表着一类处于极限吸积阶段的尘埃遮蔽类星体，它们的一些性质甚至与早期宇宙的z~6类星体相类似，而此类天体可能存在于各个宇宙时期。本项目中我们提出利用国际合作和国内既有的观测资源，借鉴对红移2-3的Hot DOG成功搜寻的经验，搜寻、证认一批在中低红移（0.5-1.5)的Hot DOGs，研究其性质和演化，并挑选较低红移的典型样本首次开展高分辨率的细节研究。同时本项目还将支持对已知中高红移的Hot DOG的一些关键后续研究。本项目的完成将对并合星系演化，超大质量黑洞的吸积等研究产生重要影响。

本项目是对承担人国家天文台吴京文研究员近年发现和命名的热尘埃遮蔽星系（Hot DOG）在中高红移成功搜寻和研究基础上，向低红移研究方向的扩展和延伸。热尘埃遮蔽星系是最先通过WISE卫星发现的，具有高红移、高光度、高尘埃温度、高吸积，高消光的一类特殊星系，可能处在星系并合演化的一个关键阶段，即中心黑洞经历强烈吸积和反馈，即将从尘埃遮蔽AGN变成光学可见类星体的阶段，它可能存在于各个宇宙时期，包括极早期宇宙和近邻宇宙。本项目主要聚焦两个方向，一是继续推进对中高红移Hot DOG样本的研究，扩大黑洞测量的样本，研究其在星系演化中的作用，二是利用我们搜寻中高红移Hot DOG的成功经验，在低红移搜索Hot DOG星系并开展后续高分辨率研究。..本项目成功利用Keck望远镜测量了一批红移2左右的Hot DOG中的黑洞质量，提出星系以Hot DOG为关键节点并合演化的路径图；后续又测量了最高红移的W2246和一个低红移W1904的黑洞质量，参与利用VLT测量几个中高红移的Hot DOG黑洞，建立起超过10个黑洞质量得到测量的Hot DOG样本。参与对已知光度最高的星系Hot DOG星系W2246开展光学和亚毫米（ALMA）的系列后续研究，发现其光度超过爱丁顿极限三倍，揭示其高光度可能来源于其对周围伴星系的直接吸积。本项目利用VLBA联合天马望远镜在一个Hot DOG中探测到小尺度射电喷流结构，预示Hot DOG可能处于AGN反馈的早期阶段。..本项目利用改进后的中高红移Hot DOG的选源方法成功选出并证认了6个红移小于0.5的Hot DOG，并对其中一个Hot DOG W1904开展了详细的后续研究，证明其性质与高红移Hot DOG相似。本项目还新开发了应用Hot DOG SED模版利用Herschel-WISE资料库交叉遴选低红移Hot DOG样本的新方法，建立起约100个源的低红移Hot DOG完备候选样本。