ORIGIN AND EVOLUTION OF THE ABUNDANCE GRADIENT ALONG THE MILKY WAY DISK

	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.