The merging dwarf galaxy UM 448: chemodynamics of the ionized gas from VLT integral field spectroscopy
The merging dwarf galaxy UM 448: chemodynamics of the ionized gas from VLT integral field spectroscopy
复制标题
合并的矮星系 UM 448：VLT 积分场光谱中电离气体的化学动力学
DOI：
10.1093/mnras/sts004
复制
发表时间：
2013
影响因子：
4.8
通讯作者：
James B
中科院分区：
文献类型：
--
作者：
James B
利用甚大望远镜/光纤大阵列多元素光谱仪光学积分场单元观测，我们详细研究了UM448，这是一个邻近的蓝色致密星系(BCG)，以前曾报道过它具有异常高的N/O丰度比。新技术望远镜/超级能见度成像仪图像显示的形态暗示着两个对比色系统的合并，而我们的Hα 发射图将UM448分成三个独立的区域，这三个区域与恒星连续谱峰不一致。UM448表现出复杂的发射线轮廓，大多数谱线由窄的[≲100 Km S−1]中央分量、下层的宽分量(∼150-300 Km S−1)和第三个窄的蓝移分量组成。所有三个分量的径向速度图都显示了UM 448上的固体旋转的迹象，其投影的旋转轴与星系的连续形态相关。基于[OIII]λλ4363,4959，[NiI]λ6584，[Sii]λλ6716,6731和[Neii]λ3868线图，给出了空间分辨的化学动力学分析。虽然UM448的东尾具有典型的BCG的电子温度(Te)，但我们在银河系主体内发现了一个区域，在那里窄而宽的[Oiii]λ4363线分量跟踪的温度相差5,000 K，氧气丰度相差0.4 Dex。我们测量了整个UM448中O、N、S和Ne的空间分辨和积分离子和元素丰度，发现它们不一致，可能是由于积分光谱中Te的通量权重所致。这对于从近宇宙和远宇宙中恒星形成星系的长缝和综合光谱中获得的丰度具有重要的意义。确实发现了一个N/O比增强的区域，该区域延伸到银河系主体内的∼0.6 kp2区域。然而，与之前的研究相反，我们没有找到大量Wolf-Rayet(WR)群体的证据，并得出结论，WR恒星本身不能对观测到的N/O过剩负责。相反，富N区的位置和紊乱的形态表明，相互作用诱导的贫金属气体的流入可能是原因。
Using Very Large Telescope/Fibre Large Array Multi Element Spectrograph optical integral field unit observations, we present a detailed study of UM 448, a nearby blue compact galaxy (BCG) previously reported to have an anomalously high N/O abundance ratio. New Technology Telescope/Superb-Seeing Imager images reveal a morphology suggestive of a merger of two systems of contrasting colour, whilst our Hα emission maps resolve UM 448 into three separate regions that do not coincide with the stellar continuum peaks. UM 448 exhibits complex emission line profiles, with most lines consisting of a narrow [full width at half-maximum (FWHM) ≲ 100 km s−1], central component, an underlying broad component (FWHM ∼ 150–300 km s−1) and a third, narrow blueshifted component. Radial velocity maps of all three components show signs of solid body rotation across UM 448, with a projected rotation axis that correlates with the continuum morphology of the galaxy. A spatially resolved, chemodynamical analysis, based on the [Oiii] λλ4363, 4959, [Nii] λ6584, [Sii] λλ6716, 6731 and [Neiii] λ3868 line maps, is presented. Whilst the eastern tail of UM 448 has electron temperatures (Te) that are typical of BCGs, we find a region within the main body of the galaxy where the narrow and broad [Oiii] λ4363 line components trace temperatures differing by 5000 K and oxygen abundances differing by 0.4 dex. We measure spatially resolved and integrated ionic and elemental abundances for O, N, S and Ne throughout UM 448, and find that they do not agree, possibly due the flux weighting ofTefrom the integrated spectrum. This has significant implications for abundances derived from long-slit and integrated spectra of star-forming galaxies in the nearby and distant universe. A region of enhanced N/O ratio is indeed found, extended over a ∼0.6 kpc2region within the main body of the galaxy. Contrary to previous studies, however, we do not find evidence for a large Wolf–Rayet (WR) population, and conclude that WR stars alone cannot be responsible for producing the observed N/O excess. Instead, the location and disturbed morphology of the N-enriched region suggest that interaction-induced inflow of metal-poor gas may be responsible.
登录
查看更多内容
非晶态星系 NGC 5253 中的氮丰度
DOI：
--
发表时间：
1987
期刊：
影响因子：
--
作者：
J. Walsh;J. Roy
通讯作者：
J. Roy
O II 的有效碰撞强度
DOI：
--
发表时间：
1993
期刊：
影响因子：
--
作者：
B. McLaughlin;K. Bell
通讯作者：
K. Bell
蓝色致密星系 (BCG) 的大质量（？）星暴宿主 - 4 个 BCG 及其伴星的光学/近红外观测
影响因子：
6.5
作者：
N. Bergvall;G. Ostlin
通讯作者：
G. Ostlin
单电离硫的电子碰撞激发的有效碰撞强度
DOI：
--
发表时间：
1996
期刊：
影响因子：
--
作者：
C. Ramsbottom;K. L. Bell;R. Stafford
通讯作者：
R. Stafford
NGC 1569 的双子座 GMOS/IFU 光谱 – I. 绘制年轻星团及其环境的特性
DOI：
10.1111/j.1365-2966.2007.12346.x
发表时间：
2007
影响因子：
4.8
作者：
M. Westmoquette;K. Exter;L. Smith;J. Gallagher
通讯作者：
J. Gallagher