ORIGIN AND EVOLUTION OF THE ABUNDANCE GRADIENT ALONG THE MILKY WAY DISK | |
Fu, J.1,2; Hou, J. L.1; Yin, J.1,2; Chang, R. X.1 | |
刊名 | ASTROPHYSICAL JOURNAL |
2009-05-01 | |
卷号 | 696期号:1页码:668-675 |
关键词 | Galaxy: abundances Galaxy: disk Galaxy: evolution Galaxy: formation |
英文摘要 | Based on a simple model of the chemical evolution of the Milky Way disk, we investigate the disk oxygen abundance gradient and its time evolution. Two star formation rates (SFRs) are considered, one is the classical Kennicutt-Schmidt law (Psi = 0.25 Sigma(1.4)(gas), hereafter C-KS law), another is the modified Kennicutt law (Psi = alpha Sigma(1.4)(gas) (V/r), hereafter M-KS law). In both cases, the model can produce some amount of abundance gradient, and the gradient is steeper in the early epoch of disk evolution. However, we find that when C-KS law is adopted, the classical chemical evolution model, which assumes a radially dependent infall timescale, cannot produce a sufficiently steep present-day abundance gradient. This problem disappears if we introduce a disk formation timescale, which means that at early times, infalling gas cools down onto the inner disk only, while the outer disk forms later. This kind of model, however, will predict a very steep gradient in the past. When the M-KS law is adopted, the model can properly predict both the current abundance gradient and its time evolution, matching recent observations from planetary nebulae and open clusters along the Milky Way disk. Our best model also predicts that outer disk ( artificially defined as the disk with R(g) >= 8 kpc) has a steeper gradient than the inner disk. The observed outer disk gradients from Cepheids, open clusters, and young stars show quite controversial results. There are also some hints from Cepheids that the outer disk abundance gradient may have a bimodal distribution. More data is needed in order to clarify the outer disk gradient problem. Our model calculations show that for an individual Milky Way-type galaxy, a better description of the local star formation is the M-KS law. |
学科主题 | 星系与宇宙学研究中心 |
WOS标题词 | Science & Technology ; Physical Sciences |
类目[WOS] | Astronomy & Astrophysics |
研究领域[WOS] | Astronomy & Astrophysics |
关键词[WOS] | CHEMO-SPECTROPHOTOMETRIC EVOLUTION ; OUTER GALACTIC DISK ; OLD OPEN CLUSTERS ; H-II REGIONS ; SUPER-NOVA REMNANTS ; LY-ALPHA SYSTEMS ; SPIRAL GALAXIES ; STAR-FORMATION ; METALLICITY GRADIENT ; PLANETARY-NEBULAE |
收录类别 | SCI |
语种 | 英语 |
WOS记录号 | WOS:000265350100054 |
公开日期 | 2010-11-08 |
内容类型 | 期刊论文 |
源URL | [http://119.78.226.72//handle/331011/12254] |
专题 | 上海天文台_星系宇宙学重点实验室 |
作者单位 | 1.Chinese Acad Sci, Key Lab Res Galaxies & Cosmol, Shanghai Astron Observ, Shanghai 200030, Peoples R China 2.Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China |
推荐引用方式 GB/T 7714 | Fu, J.,Hou, J. L.,Yin, J.,et al. ORIGIN AND EVOLUTION OF THE ABUNDANCE GRADIENT ALONG THE MILKY WAY DISK[J]. ASTROPHYSICAL JOURNAL,2009,696(1):668-675. |
APA | Fu, J.,Hou, J. L.,Yin, J.,&Chang, R. X..(2009).ORIGIN AND EVOLUTION OF THE ABUNDANCE GRADIENT ALONG THE MILKY WAY DISK.ASTROPHYSICAL JOURNAL,696(1),668-675. |
MLA | Fu, J.,et al."ORIGIN AND EVOLUTION OF THE ABUNDANCE GRADIENT ALONG THE MILKY WAY DISK".ASTROPHYSICAL JOURNAL 696.1(2009):668-675. |
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