We present Integral Field Unit GMOS-IFU data of the compact HII galaxy UM408, obtained at Gemini South telescope, in order to derive the spatial distribution of emission lines and line ratios, kinematics, plasma parameters, and oxygen abundances as well the integrated properties over an area of 3"x4".4(~750x1100 pc) located in the central part of the galaxy. The starburst in this area is resolved into two giant regions of ~375 and 250pc diameter, respectively. The ages of these two regions, estimated using Hb equivalent widths, suggest that they are coeval events of ~5Myr with stellar masses of ~10^4M_o. We have also used [OIII]/Hb and [SII]/Ha ratio maps to explore the excitation mechanisms in this galaxy. The Ha emission line was used to measure the radial velocity and velocity dispersion. We derived an integrated oxygen abundance of 12+log(O/H)=7.87 summing over all spaxels in our field of view. An average value of 12+log(O/H)=7.77 and a difference of D(O/H)=0.47 between the minimum and maximum values (7.58+-0.06-8.05+-0.04) were found, considering all data points where the oxygen abundance was measured. The spatial distribution of oxygen abundance does not show any significant gradient across the galaxy. On the other hand, the bulk of data points are lying in a region of +-2sigma dispersion (with sigma=0.1 dex) around the average value, confirming that this compact HII galaxy as other previously studied dwarf irregular galaxies is chemically homogeneous. Therefore, the new metals processed and injected by the current star formation episode are possibly not observed and reside in the hot gas phase, whereas the metals from previous events are well mixed and homogeneously distributed through the whole extent of the galaxy.
Studying the interstellar medium of HII/BCD galaxies using IFU spectroscopy
我们回顾了我们的研究结果,和以前发表的工作,对HII/BCD星系的样本的空间分辨的物理性质,主要是从积分场单位光谱与双子座/GMOS和VLT/VIMOS。我们确认,在观测的不确定性,我们的样本星系显示出几乎空间恒定的化学丰度,类似于其他低质量的星暴星系。他们还显示He II 4686发射的性质表明有多种激发源,其中沃尔夫-拉叶星被排除在主要激发源之外。最后,在这方面的贡献,我们包括一个列表的所有HII/BCD星系研究迄今为止与积分场单位光谱。
在这项工作中,我们提出了一个分析的数据立方体与仪器IFU/GMOS双子座北望远镜集中在核区域的LINER星系NGC 4579。这个星系被认为有一个1型活动星系核(参见Eracleous et al. 2002)。用于分析数据立方体的方法是PCA断层扫描(Steiner等人,2009年),其中包括应用称为主成分分析(PCA)的统计工具从数据立方体中提取信息。
HeI in the central Giant HII Region of NGC 5253. A 2D observational approach to collisional and radiative transfer effects
NGC 5253是详细研究星暴星系的理想实验室。我们首次在星暴星系中对He^+的碰撞和辐射转移效应的空间行为进行了二维研究。基于用FLAMES和GMOS获得的数据分析HeI系。碰撞效应对于单重态级联跃迁可以忽略不计,而对于三重态级联跃迁则相对重要。特别是,它们可以在Heil 7065生产线中贡献高达20%的通量。辐射转移效应在以超级星团为中心的直径为30秒差距的圆形区域内是重要的。利用6条HeI谱线的消光校正通量、T_e、n_e的实际假设、恒星吸收等效宽度以及最近的发射率,绘制了HeI丰度y^+的分布图。我们发现,在整个地图区域内,平均值为10^3 y^+ ~80.3。激发和总氦丰度y_tot之间的关系与没有丰度梯度一致。在推导He丰度的过程中,所采用的假设占主导地位。我们说明了由于主GHIIR中存在沃尔夫-拉叶星,因此检测推定的He富集的困难。数据是勉强一致的过量的N/He比在N富集区的顺序,大气中的N/He比在WR星和不确定性估计的N/He比。
GEMINI 3D spectroscopy of BAL+IR+Fe II QSOs: II. IRAS 04505-2958 an explosive QSO with hypershell and a new scenario for galaxy formation and galaxy end
从BAL + IR + Fe II类星体的研究(使用深双子座GMOS-IFU光谱)的新结果:红外天文台04505-2958。具体来说,我们详细研究了外流(OF)过程及其相关结构,主要是在两个大星系尺度:(i)两个斑点/壳(S1,S2)在半径r = 1.1和2.2 kpc的;(ii)外部超巨星壳(S3)在r = 11 kpc。此外,还讨论了在r = 80 kpc时两个非常扩展的超巨星壳层(S4,S5)的存在.从GMOS研究中获得了以下主要结果:(i)对于外部超巨星壳层S3,电离气体的运动学GMOS图显示出与在NGC 5514中观察到的爆炸外部超巨星壳层原型非常相似的特征。(ii)这个超巨星壳层S3-的主要节点K1、K2和K3 -显示了与星暴+ OF/激波存在相关的恒星星族和发射线比率。(iii)内壳层S1和S2的结构、OF成分和性质与Mrk 231核壳层中检测到的非常相似。(iv)壳层S1+S2和S3在PA = 131处对齐:即表明OF过程处于具有双极结构的吹出阶段。此外,壳体S4和S5(80-100 kpc尺度)在PA = 40时对齐,即:垂直于内部OF的双极OF。最后讨论了BAL + IR + Fe II类星体中与HyNe有关的UHE宇宙射线和中微子/暗物质的产生。