星系金属丰度的研究进展(Ⅱ):光度-金属丰度关系

The Methods and Study Progress about Estimating Metallicities of Galaxies(Ⅱ): Luminosity-Metallicity Relation

金属丰度与星系光度是星系的重要特征参量,研究它们之间的关系有助于理解星系中恒星质量与金属成分的累积过程。评述了星系的光度-金属丰度关系的最新研究进展,包括对近邻星系、中等红移星系(0．4<z<1)及高红移星系(z>2)的研究结果．由于观测样本跨越较宽的宇宙学时标,可以由此来探讨这一关系的演化过程,从而帮助理解星系演化的整体图景。

The luminosity-metallicity （L-Z） relation （ stellar mass-metallicity, mass-Z, relation） is one of the fundamental parameters of galaxies, and can trace the assembly history of metals and stellar masses in the galaxies.We review the study progress about the L-Z and mass-Z relations of galaxies,including the local, the intermediate-z （0.4 〈 z 〈 1） and the high-z （z 〉 2） galaxies. Since the observations extend to a wide cosmic time scale,this can help to undertand and the evolutionary process of the L-Z relations of galaxies, hence to understand the whole evolutionary scenario of galaxies. In Sect.2, we introduce the relations between B band＂ absolute magnitudes and metallicities （MB-Z） of nearby galaxies, including the irregular, the spiral galaxies, the UV-selected and nearby HII galaxies, the KISS sample, the 2dFGRS sample, and the SDSS galaxies. We present some of the important formulas of such relations.In Sect. 3, we present the study about the relationship between near-infrared J, H, K band absolute magnitudes and metallicities of nearby galaxies. The majority is the result of 400 KISS galaxies obtained from 2MASS. We also mention the MK-Z relations of a small sample of distant luminous infrared galaxies. In Sect.4, we specially introduce the relations between stellar mass and metallicities of nearby star-forming galaxies derived from the SDSS database. All these results show that the more luminous （massive） galaxies are more metal-rich generally. The luminosity correlates with metallicity over 10 magnitudes in luminosity and 2 dex in metallicity, with indication that the relationship may be environmental and morphology flee. In Sect.5, we introduce the L-Z （mass-Z） relations of the intermediate-z and high-z galaxies. With the increasing ability of observations, more and more distant galaxies have been obtained their L-Z （mass-Z） relations, such as the intermediate-z（0.4 〈 z 〈 1） luminous infrared galaxies, the galaxies selected from GOODS, CFRS, DGSS fields, and the high-z（z ≈ 3）LBGs. These results show that there exists one L-Z （mass-Z） relation in the distant universe, where the less luminous galaxies may have lower metallicities generally. Especially, comparing the L-Z （mass-Z） relations of these distant galaxies with those of the local ones, it shows that the distant ones are more metal-deficient than the local ones at a given luminosity or stellar mass, i.e. the galaxies with 0.4 〈 z 〈 1 are about 0.14-0.4 dex more metal-deficient, and the galaxies with z 〉 2 are about 0.56-0.7 dex more metal-deficient relatively. They should produce these important parts of their metals in the consequent evolutionary process. The conclusions and prospects are given in Sect.6.