| 摘要: | 類星體是宇宙最明亮的天體。類星體如何形成是天文學上一個非常重要且尚待解決的問題。目前的研究認為類星體以及光度較低的其它活躍星系核的形成都與星系的形成有密切的關系。特別是星系的核球大小與星系中心的巨質量黑洞的質量有一致的關係。但對於高紅移的類星體，能被觀測到的高紅移類星體其光度都非常巨大，因此我們預期這些高紅移的類星體有巨大的黑洞及星系核球。但當時的星系應該只是在星系演化的初期，因此其星系核球應該不會太巨大。因此在高紅移時，類星體與其宿主星系的關係究竟是什麼？或更一般的說，活躍星系核會處在什麼樣的星系中？例如棒旋星系和合併星系系統都被發現比一般旋渦星系及非合併星系有更多的活躍星系，那活躍星系核形成的原因和與星系的關係又是什麼呢？而不同的宿主星系是否會對活躍星系核的觀測性質造成影響？一般所熟知的一型和二型的活躍星系是否真的跟其宿主星系無關而只跟觀測角度有關？不同類形的活躍星系是否有不同的起源？對這些重大問題我們仍然所知不多。本計畫預計要延續我們之前己有的相關成果，持續在這些重要問題做進一步的探討和研究。在過去幾年，我們在相關的問題上有了一些根本的重大進展。例如，我們使用ALMA的CO觀測，發現了許多紅移大於7的高紅移類星體候選天體。其中之一，我們有使用可見光－近紅外線觀測，確認它是處在紅移z=7.09的類星體。因此我們所觀測到的CO也成為人類歷史上所偵測到的最遙遠分子。我們也發現一顆氫原子譜線非常明亮的高紅移類星體，但其譜線寬度與一般類星體比較卻非常窄。我們也發現一些紅色類星體的顏色具有時變現象。此外，我們發現西佛一型和二型的活躍星系其宿主星系有很大的不同。另外我們發現銀河系附近的活躍星系核，通常都只存在於那些曾發生過核心星球劇增的星系。另外，我們也發現某些很正常的橢圓星系具有很高的恆星形成率，但星系中與恆星形成相關的氣體的動力現象卻與星系中的恆星非常不同。本計畫將使用不同的觀測手段，包括可見光-近紅外線光譜觀測、毫米波與次毫米波陣列觀測、可見光的光變研究、以及大型資料庫分析，來持續研究活躍星系核與星系演化的關聯性等重大問題。本計畫的許多研究方式都需要用到國內外的望遠鏡，並實際到國外觀測。因此需要國外移地研究的補助。這些研究過程也能訓練碩博士生及博士後熟悉天文學的各種研究方法。本計畫的研究的成果，將有可能對未來活躍星系核的研究產生重大影響。 ;Quasi-stellar objects (QSOs) are among the brightest objects in the universe. The origin of QSOs is still an important unsolved problems of modern astronomy. Current study suggests that the formation of QSOs and other less luminous active galactic nuclei (AGNs) is closely related to the formation of galaxies. In particular, the masses of the super mass black holes (SMBHs) of QSOs and the masses of galactic spheroids are closely correlated. For observed high-redshift QSOs, we expect that these QSOS should have huge SMBHs and galactic nuclei so they would be bright enough to be detectable. On the other hand, a high-redshift galaxy-QSO system should only be in the very early evolution stage of the galaxy-QSO system, so the galactic nucleus could not be too large. So what is the relationship between a QSO and its host galaxy at high redshifts? Or more generally, we might ask what kind of galaxies can host an AGN. For example, both barred spiral galaxies and merging/interacting galaxies were found to have more AGNs than normal spiral and non-interacting ones. What is the mechanism for the formation of AGNs in these galaxies? Another general problems include: Will different host galaxies affect the observed nature of AGNs, i.e., different types of AGNS have different host galaxies? Are different types of AGNs intrinsically different? What is the origin of the difference? The purpose of this project is to study on these important issues following our previous results.In the past few years, we have made some significant progress on the related issues. For example, we discovered several high-redshift (z>7) QSO candidates by using CO scanning observations of ALMA. We carried out optical-NIR observations for one candidate and confirmed that it was a QSO with a redshift of z = 7.09. The CO detection becomes the most distant molecular gas observed in human history. We also found a high-redshift QSO with a very luminous Lyman α emission line, but the Lyman α line width is very narrow. We also found that the color of red QSOs can vary significantly. Besides, we found that the host galaxies of Seyfert 1 and Seyfert 2 are very different. In addition, we found that nearby AGNs usually exists only in those galaxies that have experienced nuclear starbursts. We also found that some elliptical galaxies have high star formation rates, but the dynamics of the gas associated with the star formation activity is quite different from that of the stellar populations in the galaxies.In this project, we will use different observational techniques to probe relevant questions. Our study will utilize optical/near infrared spectral observations, millimeter and sub-millimeter observations, optical variability observations, and sky survey data analyses to investigate related problems in the connection of galaxy-AGN evolution. We will use a lot of telescopes in other countries, and thus require traveling budgets for oversea observations. This project will provide observational training for graduate students and postdocs. The results of this project are expected to have important impacts on the field of AGN researches. |
