How galaxies assemble masses through their own star formation or interaction with the external environment is still an important topic in the field of galaxy formation and evolution.We use Value Added Catalogs with ga...How galaxies assemble masses through their own star formation or interaction with the external environment is still an important topic in the field of galaxy formation and evolution.We use Value Added Catalogs with galaxy features that are spatially and temporally resolved from Sloan Digital Sky Survey Data Release 17 to investigate the mass growth histories of early-type galaxies(ETGs)and late-type galaxies(LTGs).We find that the mass growth of ETGs is earlier than that of LTGs for massive galaxies(M_(*)>10^(10)M_⊙),while low-mass(M_(*)≤10^(10)M_⊙)ETGs have statistically similar mass assembly histories as low-mass LTGs.The stellar metallicity of all massive galaxies shows a negative gradient and basically does not change with time.However,in low-mass galaxies,the stellar metallicity gradient of elliptical galaxies is negative,and the stellar metallicity gradient of lenticular and spiral galaxies evolves from positive to negative.ETGs are not all in a high-density environment,but exhibit mass dependence.As the tidal strength increases,the star formation rate of low-mass ETGs rapidly decreases.These results support a picture where massive galaxies exhibit inside-out quenching mode,while low-mass galaxies show outside-in quenching mode.Environmental effects play an important role in regulating the mass assembly histories of low-mass ETGs.展开更多
基金supported by the Natural Science Research Programs of Jiangsu Province University(23KJB160001 and 23KJB140004)by the support of the scientific research fund of Jiangsu Second Normal University(927801/032)+1 种基金supported by the Hebei Natural Science Foundation(grant No.A2022408002)the Fundamental Research Funds for the Universities in Hebei Province(grant No.JYQ202003)。
文摘How galaxies assemble masses through their own star formation or interaction with the external environment is still an important topic in the field of galaxy formation and evolution.We use Value Added Catalogs with galaxy features that are spatially and temporally resolved from Sloan Digital Sky Survey Data Release 17 to investigate the mass growth histories of early-type galaxies(ETGs)and late-type galaxies(LTGs).We find that the mass growth of ETGs is earlier than that of LTGs for massive galaxies(M_(*)>10^(10)M_⊙),while low-mass(M_(*)≤10^(10)M_⊙)ETGs have statistically similar mass assembly histories as low-mass LTGs.The stellar metallicity of all massive galaxies shows a negative gradient and basically does not change with time.However,in low-mass galaxies,the stellar metallicity gradient of elliptical galaxies is negative,and the stellar metallicity gradient of lenticular and spiral galaxies evolves from positive to negative.ETGs are not all in a high-density environment,but exhibit mass dependence.As the tidal strength increases,the star formation rate of low-mass ETGs rapidly decreases.These results support a picture where massive galaxies exhibit inside-out quenching mode,while low-mass galaxies show outside-in quenching mode.Environmental effects play an important role in regulating the mass assembly histories of low-mass ETGs.
文摘目的进一步确定二价金属离子转运体1(DMT1)在人胎盘绒毛膜癌细胞(Be Wo)中的表达定位,以及缺铁状态下m RNA的表达变化。方法采用免疫细胞化学技术观察DMT1在Be Wo细胞中的表达定位,采用实时荧光定量聚合酶链反应检测DMT1在Be Wo细胞缺铁状态下m RNA的表达变化。结果 DMT1在Be Wo细胞中呈阳性表达,其弥漫性表达定位于细胞质和细胞膜上;DMT1+IRE m RNA和DMT1-IRE m RNA的相对表达量随缺铁干预浓度和时间的增加而上调。DMT1+IRE m RNA的相对表达量高于DMT1-IRE m RNA。结论DMT1大量表达在Be Wo细胞质和细胞膜上,且表达受机体不同铁水平的调节,说明其在胎盘铁转运过程中发挥重要作用,为进一步探讨胎盘铁转运分子机制提供实验基础。
