arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1612.01546astro-ph.GA
收藏

SDSS-IV MaNGA:星系中空间分辨的恒星形成历史作为星系质量和类型的函数

SDSS-IV MaNGA: Spatially resolved star formation histories in galaxies as a function of galaxy mass and type

Daniel Goddard, Daniel Thomas, Claudia Maraston, Kyle B. Westfall, James Etherington, Rogerio Riffel, Nicolas D. Mallmann, Zheng Zheng, Maria Argudo-Fernandez, … 展开作者

Daniel Goddard, Daniel Thomas, Claudia Maraston, Kyle B. Westfall, James Etherington, Rogerio Riffel, Nicolas D. Mallmann, Zheng Zheng, Maria Argudo-Fernandez, Jianhui Lian, Matthew A. Bershady, Kevin Bundy, Niv Drory, David R. Law, Renbin Yan, David Wake, Anne-Marie Weijmans, Dmitry Bizyaev, Joel R. Brownstein, Richard R. Lane, Roberto Maiolino, Karen L. Masters, Michael R. Merrifield, Christian Nitschelm, Kaike Pan, Alexandre Roman-Lopes, Thaisa Storchi-Bergmann, Donald P. Schneider

摘要:

我们研究的内部梯度的恒星人口属性$1.5\;R_{\rm e}$内的721个星系的恒星质量范围之间的$10^{9}\;M_{\odot}$ $10^{11.5}\;M_{\odot}$从SDSS-IV MANGA IFU调查的代表性样本。通过使用我们的全光谱拟合代码FIREFLY,我们得到的光和质量加权恒星的人口属性和径向梯度,以及完整的恒星形成和金属富集的历史。我们还量化了不同的恒星种群模型和全光谱拟合程序对导出的恒星种群特性和径向梯度测量的影响。在我们的分析中,我们发现,年龄梯度往往是浅的早型和晚型星系。早期类型的{ \em质量加权}年龄梯度为正($\sim 0.09\; {\rm dex}/R_{\rm e}$),表明恒星形成的“由外向内”的进展,而晚期类型的星系有负的{ \em轻加权}年龄梯度($\sim -0.11\; {\rm dex}/R_{\rm e}$),表明盘的“由内向外”的形成。我们检测到负的金属丰度梯度在早期和晚期类型的星系,但这些都是显着陡峭的晚期类型,这表明径向依赖的化学富集过程和气体流入和金属运输的影响是更加明显的光盘。这两种形态类别的金属丰度梯度与星系质量相关,随着星系质量的增加,负金属丰度梯度变得更陡。晚型星系与质量的相关性更强,与早型星系的$d(\nabla [Z/H])/d(\log M)\sim -0.05\pm 0.05\;$相比,其斜率为$d(\nabla [Z/H])/d(\log M)\sim -0.2\pm 0.05\;$。这一结果表明,合并的历史发挥了相对较小的作用,在塑造星系的金属丰度梯度。

英文摘要:

We study the internal gradients of stellar population properties within $1.5\;R_{\rm e}$ for a representative sample of 721 galaxies with stellar masses ranging between $10^{9}\;M_{\odot}$ to $10^{11.5}\;M_{\odot}$ from the SDSS-IV MaNGA IFU survey. Through the use of our full spectral fitting code FIREFLY, we derive light and mass-weighted stellar population properties and their radial gradients, as well as full star formation and metal enrichment histories. We also quanfify the impact that different stellar population models and full spectral fitting routines have on the derived stellar population properties, and the radial gradient measurements. In our analysis, we find that age gradients tend to be shallow for both early-type and late-type galaxies. {\em Mass-weighted} age gradients of early-types are positive ($\sim 0.09\; {\rm dex}/R_{\rm e}$) pointing to "outside-in" progression of star formation, while late-type galaxies have negative {\em light-weighted} age gradients ($\sim -0.11\; {\rm dex}/R_{\rm e}$), suggesting an "inside-out" formation of discs. We detect negative metallicity gradients in both early and late-type galaxies, but these are significantly steeper in late-types, suggesting that radial dependence of chemical enrichment processes and the effect of gas inflow and metal transport are far more pronounced in discs. Metallicity gradients of both morphological classes correlate with galaxy mass, with negative metallicity gradients becoming steeper with increasing galaxy mass. The correlation with mass is stronger for late-type galaxies, with a slope of $d(\nabla [Z/H])/d(\log M)\sim -0.2\pm 0.05\;$, compared to $d(\nabla [Z/H])/d(\log M)\sim -0.05\pm 0.05\;$ for early-types. This result suggests that the merger history plays a relatively small role in shaping metallicity gradients of galaxies.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑