期刊
ASTRONOMY & ASTROPHYSICS
卷 539, 期 -, 页码 -出版社
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201117718
关键词
galaxies: evolution; galaxies: abundances; galaxies: high-redshift
资金
- CNRS-INSU
- Programme National Cosmologie-Galaxies (France)
- French ANR [ANR-07-JCJC-0009]
- INAF [PRIN-2008/1.06.11.02]
- Agence Nationale de la Recherche (ANR) [ANR-07-JCJC-0009] Funding Source: Agence Nationale de la Recherche (ANR)
Aims. The estimate of radial abundance gradients in high-redshift galaxies allows to constrain their star formation history and their interplay with the surrounding intergalactic medium. Methods. We present VLT/SINFONI integral-field spectroscopy of a first sample of 50 galaxies at z similar to 1.2 in the MASSIV survey. Using the N2 ratio between the [N II]6584 and H alpha rest-frame optical emission lines as a proxy for oxygen abundance in the interstellar medium, we measured the metallicity of the sample galaxies. We developed a tool to extract spectra in annular regions, leading to a spatially resolved estimate of the oxygen abundance in each galaxy. We were able to derive a metallicity gradient for 26 galaxies in our sample and discovered a significant fraction of galaxies with a positive gradient. Using a simple chemical evolution model, we derived infall rates of pristine gas onto the disks. Results. Seven galaxies display a positive gradient at a high confidence level. Four out of these are interacting, and one is a chain galaxy. We suggest that interactions might be responsible for shallowing and even inverting the abundance gradient. We also identify two interesting correlations in our sample: a) galaxies with higher gas velocity dispersion have shallower/positive gradients; and b) metal-poor galaxies tend to show a positive gradient, whereas metal-rich ones tend to show a negative one. This last observation can be explained by the infall of metal-poor gas into the center of the disks. We address the question of the origin of this infall under the influence of gas flows triggered by interactions and/or cold gas accretion. All the data published in this paper are publicly available at the time of publication following this link: http://cosmosdb.lambrate.inaf.it/VVDS-SINFONI.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据