本文選題：星系團　切入點：環(huán)境　出處：《中國科學技術大學》2013年博士論文

【摘要】：星系團是宇宙中物質分布最致密的區(qū)域,是星系演化的天然實驗室。在星系團中,從中心區(qū)域到外圍,團成員物理性質,如形態(tài)、恒星形成率、星族年齡等,呈現(xiàn)出不同程度的差異。星系環(huán)境的研究則是從星系分布最致密的區(qū)域到最稀疏的區(qū)域,分析環(huán)境效應對星系物理性質及其演化路徑的影響,而不僅僅局限于星系團等區(qū)域。SDSS巡天提供了大樣本的近鄰星系樣本,也提供了上百萬個星系的紅移,從而能夠對星系環(huán)境進行比較準確的估計。最近,基于SDSS的樣本,有關環(huán)境效應如何影響星系演化的這一類研究已經(jīng)取得一系列成果,并且依然是很熱門的課題。在本論文中,我們利用SDSS的數(shù)據(jù)和Beijing-Arizona-Taiwan-Connecticut (BATC)的多波段觀測數(shù)據(jù),對近鄰星系團Abell671(A671)的子結構、光度函數(shù)、團成員恒星形成歷史等性質進行研究。另外,我們還用COSMOS場的數(shù)據(jù)研究了介于寧靜星系和恒星形成星系之間的綠谷(Green Valley)星系的物理性質和環(huán)境,試圖探討從紅移z～1到現(xiàn)在,環(huán)境效應在這類星系的形成過程中所起的作用。 本文第二章,我們利用SDSS的測光和光譜數(shù)據(jù),以及BATC15個中帶濾光片的多波段觀測數(shù)據(jù),對星系團A671進行了測光和光譜研究。通過將BATC的數(shù)據(jù)和SDSS的數(shù)據(jù)進行匹配,我們在A671581x58'的視場中匹配到了985個V波段亮于20.0mag的星系,其中包括103個由光譜紅移確定的團成員星系。為了選取更多的暗成員星系,我們對BATC觀測的數(shù)據(jù)進行能譜擬合,估計星系的測光紅移。利用測光紅移,結合顏色—星等圖,我們新選取到了97個亮于BATC hBATC=19.5mag的新團成員�；谶@個擴大了的樣本,我們研究了A671的子結構。我們發(fā)現(xiàn),僅用103個亮成員星系來測量時,子結構非常明顯。但是在引入暗成員之后,子結構被平滑掉了。我們認為暗成員的測光紅移值在指示子結構時不是太準確。A671在SDSS r波段的光度函數(shù)可以很好的用Schechter函數(shù)來擬合,暗端斜率比較平,α=-1.12。我們用STARLIGHT來擬合SDSS的光譜,研究了亮成員的恒星形成歷史。我們發(fā)現(xiàn),處在星系團核心區(qū)域的早型星系要比外圍的年老。而金屬豐度則沒有表現(xiàn)出環(huán)境效應。無論是早型星系還是晚型星系,它們的星族年齡和金屬豐度都和恒星質量強烈相關。我們的發(fā)現(xiàn)支持"downsizing"的星系演化模式。通過將早型星系的Lick指數(shù)和簡單星族的模型進行比較,我們得到了早型星系的年齡、[Fe/H].[Mg/Fe]、[C/Fe]、[N/Fe]等參數(shù)。我們發(fā)現(xiàn),星系團核心區(qū)域的早型星系的星族年齡指針Hβ等值寬度要比外圍的小,這說明中心星系較為年老。而指示總金屬豐度的[MgFe]'指數(shù),則沒有表現(xiàn)出環(huán)境效應。得到的[Fe/H].[Mg/Fe]等參數(shù)與星系速度彌散值相關,這與以前的研究結果符合。 論文第三章,我們在COSMOS場中選取了一個數(shù)目約為2350個,處于z=[0.2,1.0]的”Green Valley"星系樣本(以下稱為綠星系),研究了他們的形態(tài)、光譜和環(huán)境。我們用經(jīng)過塵埃改正過的NUV-r+顏色來定義green valley,這有助于我們從綠谷地帶中剔除掉富塵埃的恒星形成星系,從而選取到真實的過渡類型星系。綠星系在Gini-Asymmetry和Gini-M20的參數(shù)空間上都處在紅、藍星系之間。利用ZEST形態(tài)分類表,我們發(fā)現(xiàn)大概有60%--70%的綠盤星系有大的或者中等的核球成分,只有5%-10%綠星系是純盤系統(tǒng)。綠星系的疊加譜有中等強度的[OⅡ], Ha和Hβ發(fā)射線。星族分析的結果顯示,綠星系比紅星系年輕,但是比藍星系年老。我們用∑10研究了綠星系的環(huán)境。我們發(fā)現(xiàn),在z0.7時,綠星系和藍星系處在相似的環(huán)境中。但是在z0.7,大量的M*1010.0M⊙的綠星系出現(xiàn)在了高密度區(qū)域,這顯著的不同于藍星系。綠星系的形態(tài)和光譜特征符合過渡類型星系的性質。我們討論了抑制恒星形成活動(quenching)的機制。在本文中,我們無法估計AGN反饋對quenching的影響。最后,我們認為環(huán)境效應,最有可能的是Starvation和Harassment,會在z0.5之后對M*1010.0M⊙的藍星系起重要影響,從而使它們轉變?yōu)榧t星系。研究結果支持,從z≈1到z=0,大質量星系中mass quenching始終占主導地位；而對于小質量星系,在z0.5時,environment quenching占主導。
[Abstract]:Regional material distribution of galaxies is the most dense in the universe, is a natural laboratory. The evolution of galaxies in the cluster, from the central area to the periphery, members of physical properties, such as morphology, star formation rate, population age, showing different degrees of difference. The research environment is from the Galaxy Galaxy distribution a dense region to the sparse region, analysis of the impact of environmental effect on the physical properties of galaxies and its evolution path, and not just in the cluster region.SDSS survey provides a large sample of neighboring galaxy samples also provide millions of Galaxy redshift, so as to be able to accurately estimate the Galactic environment. SDSS, based on how the environmental effect of this kind of research on the evolution of galaxies has made a series of achievements, and still is a very hot topic. In this paper, we use SDSS data and Beijing-Arizona-Taiwan-Connecticut (BATC) of the multi band observation data, Abell671 on neighboring galaxies (A671) subsystem, the luminosity function, members of the star formation history of nature. In addition, we also use the COSMOS field data of peace between galaxies and star forming galaxies between the Green Valley (Green Valley) the physical properties and the environment the galaxy, attempts to explore from redshift z ~ 1 to now, the environmental effect on the formation process of the galaxy's role.
In the second chapter, we use the photometric and spectroscopic data of SDSS, BATC15 and a multi band bandpass filter observations of galaxy clusters by A671 photometry and spectroscopy. By matching the BATC data and SDSS data, we in the A671581x58'field in the match to the 985 V band in 20.0mag light the galaxy, which includes 103 members is determined by the spectral redshift galaxies. In order to select more dark galaxies, we observed data of BATC spectra fitting, photometric redshift estimation of galaxies. Using photometric redshifts, combining the color magnitude diagram, we selected the new 97 BATC hBATC=19.5mag in new light the members of the delegation. Based on expanded sample, we studied the structure of A671. We found that only 103 bright galaxies to measure, the sub structure is very obvious. But after the introduction of dark members, sub structure Is smoothed out. We think the value of the member in the dark photometric redshift indicating the sub structure is not too accurate.A671 in the SDSS r band luminosity function can be very good with the Schechter function to fit the faint end slope, relatively flat, spectral fitting SDSS alpha =-1.12. we use STARLIGHT to study, members of the bright star formation history we found that in early type galaxies cluster core region than the periphery of old age. And the metal abundance showed no environmental effect. Whether early type galaxies or late type galaxies, their stellar age and metallicity are strongly associated with star quality. Our findings support the "downsizing" of the galaxy evolution model by the early type galaxies Lick index and simple population model comparison, we get the early type galaxies age, [Fe/H].[Mg/Fe], [C/Fe], [N/Fe] and other parameters. We found that the cluster core area New age pointer H beta equivalent width of early type galaxies than peripheral small, indicating that the center of the galaxy. While the older, indicating the total metallicity [MgFe]'index showed no effect. The environment parameters such as [Fe/H].[Mg/Fe] and Galaxy velocity dispersion values obtained, the results consistent with previous studies.
In the third chapter, we in the COSMOS field in the selection of a number of about 2350, in the "z=[0.2,1.0] Green Valley" (hereinafter referred to as green galaxies, galaxies) they were studied, and the environment. We use the spectrum by dust corrected NUV-r+ color to define Green Valley, which helps we removed from the Green Valley area of the dust rich star forming galaxies, so as to select the type of transition. The real green Galaxy Galaxy in the parameter space of Gini-Asymmetry and Gini-M20 are in red, LAN-STAR. Using ZEST morphology classification, we found that the green disc galaxies about 60%--70% of large or medium nuclear the ball, only 5%-10% is pure green Galaxy disk system. The spectra of galaxies superimposed green medium strength [O II], Ha and H beta emission lines. Population analysis shows that green galaxies younger than red galaxies, but than LAN-STAR. I am old We use 10 sigma of green Galaxy environment. We found that in the z0.7, and LAN-STAR in the green Galaxy in a similar environment. But in z0.7, a large number of M*1010.0M, the green galaxy appears in the high density region, which significantly different from LAN-STAR. The morphological and spectral characteristics of green Galaxy properties with the transition type galaxies. We discuss the suppression of star formation activity (quenching) mechanism. In this paper, we cannot estimate the effect of feedback on AGN quenching. Finally, we believe that the environmental effect, the most likely is Starvation and Harassment, in the z0.5 of M*1010.0M after the LAN-STAR system has an important effect, thus make them into red galaxies. The results support from z = 1 to z=0, mass quenching always dominant position of massive galaxies; and for low mass galaxies, in z0.5, environment and quenching are dominant.

【學位授予單位】：中國科學技術大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：P157.9

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本文編號：1664130