本文選題：相互作用 + 星系對(duì)��； 參考：《上海師范大學(xué)》2013年碩士論文

【摘要】：星系間的相互作用及并合在星系的演化過程中起著十分重要的作用。數(shù)值模擬實(shí)驗(yàn)表明，星系與星系之間的相互作用會(huì)對(duì)星系內(nèi)部的恒星及氣體產(chǎn)生強(qiáng)烈的擾動(dòng)，進(jìn)而對(duì)星系的光度、顏色、形態(tài)、金屬豐度及內(nèi)部恒星形成活動(dòng)產(chǎn)生重要影響。一般來說，相互作用“星系對(duì)”比場(chǎng)星系具有更強(qiáng)的恒星形成，顏色上偏藍(lán)，形態(tài)上更趨于不規(guī)則。大量的統(tǒng)計(jì)研究結(jié)果也支持類似的觀點(diǎn)。然而由于觀測(cè)條件及數(shù)據(jù)的限制，不同的研究工作在“星系對(duì)”統(tǒng)計(jì)樣本的選取及統(tǒng)計(jì)方法的采用上具有顯著的差異，因而得到的統(tǒng)計(jì)研究結(jié)果也往往不完全一致。 本文基于Allam（2004）的工作，從SDSS DR2的測(cè)光數(shù)據(jù)庫中證認(rèn)出一個(gè)大的高質(zhì)量的相互作用“星系對(duì)”樣本，其中包含8792對(duì)孤立的相互作用“星系對(duì)”。這些“星系對(duì)”具有投影間距小，周圍沒有其他干擾星系等特點(diǎn)。這些特點(diǎn)對(duì)研究相互作用對(duì)星系性質(zhì)的影響十分重要。此外，本文通過收集該樣本星系的各種測(cè)光數(shù)據(jù)及光譜數(shù)據(jù)，進(jìn)一步建立了一個(gè)包含測(cè)光資料及光譜資料的更完善的星系樣本，其中包含了2779個(gè)相互作用星系。這部分星系是本文用來做統(tǒng)計(jì)研究的主要星系樣本，簡(jiǎn)稱為光譜樣本（SGS）。為了與正常場(chǎng)星系進(jìn)行對(duì)比，我們還依據(jù)相互作用星系光譜樣本（SGS）的紅移分布，光度分布和聚集度參數(shù)分布，從SDSS DR7中隨機(jī)挑選出了場(chǎng)星系樣本，建立了對(duì)照星系樣本（CGS）。 通過對(duì)這兩個(gè)樣本（SGS和CGS）的比較，發(fā)現(xiàn)SGS與CGS在以下幾個(gè)方面具有顯著差異： 1）g-r顏色分布的差異。如果把星系的g-r顏色粗略分為三個(gè)層次，藍(lán)、紅及中間顏色，則與場(chǎng)星系樣本（CGS）相比，相互作用星系樣本（SGS）具有更高比例的藍(lán)星系及紅星系。具有更多藍(lán)星系的原因通常歸結(jié)為相互作用所觸發(fā)的恒星形成所致。而對(duì)于SGS中存在更高比例的紅星系的原因，人們沒有統(tǒng)一的看法。通常認(rèn)為，星系環(huán)境是造成這一現(xiàn)象的重要因素。因?yàn)橄鄬?duì)場(chǎng)星系來說，相互作用星系一般處于高密度的星系環(huán)境中，根據(jù)環(huán)境與顏色的關(guān)系，這類星系顏色要偏紅。然而，本文的SGS星系都是孤立的“星系對(duì)”，故環(huán)境應(yīng)該不是造成這種差異的主要因素。通過本文的研究，我們認(rèn)為SDSS對(duì)緊密“星系對(duì)”的低精度測(cè)光可能是原因之一。 2）星系中心（fiber）顏色及整體（Petrosian）顏色的差異。通過對(duì)SGS及CGS樣本中星系的fiber顏色及Petrosian顏色進(jìn)行分析，我們發(fā)現(xiàn)，相互作用星系的恒星形成具有向星系中心聚集的跡象，，這一結(jié)論與大部分相互作用星系的數(shù)值模擬結(jié)果一致。 3）光度（質(zhì)量）-金屬豐度關(guān)系的差異。研究表明，與場(chǎng)星系樣本（CGS）相比，相互作用星系樣本（SGS）在光度/質(zhì)量－金屬度關(guān)系曲線上存在明顯的offset（偏低），我們認(rèn)為這是由于相互作用引發(fā)氣體向星系中心下落進(jìn)而稀釋星系中心的金屬豐度引起。 最后，我們還利用本文所建立相互作用星系樣本，對(duì)Faber等在2007年提出的幾種星系演化（從藍(lán)云到紅序）的途徑mix quenching、early quenching及l(fā)ate quenching進(jìn)行了分析，我們認(rèn)為mix quenching可能是星系演化的正確途徑。
[Abstract]:Intergalactic interactions and intergalactic interactions play an important role in the evolution of galaxies. Numerical simulations show that the interaction between galaxies and galaxies will cause strong disturbances in the stars and gases inside the galaxy, which is important for the galaxy's luminosity, color, morphology, metallicity, and internal star formation. In general, the interaction of "Galaxy pairs" has a stronger star formation than the field galaxy, the color is blue, and the shape is more irregular. A large number of statistical research results support similar views. However, due to the conditions of observation and the limitation of data, different research works in the selection and statistics of "galaxy pair" statistical samples. There are significant differences in the adoption of the law, so the statistical results obtained are often inconsistent.
Based on the work of Allam (2004), this paper recognizes a large, high-quality "galaxy pair" sample from the SDSS DR2 photometry database, which contains 8792 pairs of isolated interaction "Galaxy pairs". These "Galaxy pairs" have small projection spacing, and there are no other interfering galaxies around them. The effect on the properties of galaxies is very important. In addition, by collecting the various photometric data and spectral data of the sample galaxy, a more perfect Galaxy sample containing the photometric data and spectral data is further established, including 2779 interacting galaxies. This part of the galaxy is the main part of this paper to do statistical research. In order to compare with normal field galaxies, in order to compare with the normal field galaxies, we also choose the sample of the field galaxies randomly from the SDSS DR7 and set up a sample of the control galaxies (CGS), in order to compare with the normal field galaxies, in order to compare with the normal field galaxies, we also choose the distribution of the red shift, the luminosity distribution and the aggregation parameters of the interacted Galaxy spectrum sample (SGS), and the random sample of the field galaxies is selected from the SDSS DR7.
By comparing these two samples (SGS and CGS), it is found that there are significant differences between SGS and CGS in the following aspects:
1) differences in G-R color distribution. If the G-R color of galaxies is roughly divided into three levels, blue, red and intermediate colors, the interaction Galaxy sample (SGS) has a higher proportion of the LAN-STAR and red stars compared with the field Galaxy sample (CGS). The reasons for the more blue galaxies are usually attributed to the star formation triggered by interaction. There is no unified view of the reasons for the higher proportion of the red star system in SGS. It is generally believed that the galaxy environment is an important factor in this phenomenon. Because the relative galaxies are generally in the high density Galaxy environment, the color of these galaxies should be red according to the relationship between the environment and color. The SGS galaxies in this paper are isolated "Galaxy pairs", so the environment should not be the main factor in this difference. Through this study, we think that SDSS may be one of the reasons for the compact "galaxy pair" low precision photometry.
2) the difference in the color of the galaxy center (fiber) and the color of the whole (Petrosian). By analyzing the fiber color and the Petrosian color of the galaxies in the SGS and CGS samples, we find that the star formation of the interacting galaxies has a sign of aggregation to the center of the galaxy. This conclusion is in agreement with the numerical simulation results of most interacting galaxies.
3) differences in the relationship between photometric (mass) - metal abundance. The study shows that, compared with the field Galaxy sample (CGS), the interacted Galaxy sample (SGS) has an obvious offset (low) on the photometric / mass metallicity relation curve, which we think is due to the metal abundance of the interaction of gas from the center of the galaxy to the center of the galaxy and then diluting the center of the galaxy. Cause.
Finally, we also use the sample of interacting galaxies in this paper to analyze several kinds of galaxy evolution (from blue cloud to red order) proposed by Faber in 2007, such as mix quenching, early quenching and late quenching, and we think mix quenching may be the correct way of galaxy evolution.
【學(xué)位授予單位】：上海師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：P15

【共引文獻(xiàn)】

相關(guān)期刊論文 前1條

1 張聰慧;孫艷春;;星系對(duì)的選擇及其研究進(jìn)展[J];天文學(xué)進(jìn)展;2013年03期

相關(guān)博士學(xué)位論文 前1條

1 潘治政;星系環(huán)境和星系質(zhì)量對(duì)星系演化的影響[D];中國(guó)科學(xué)技術(shù)大學(xué);2013年

本文編號(hào)：2084784