强/超强紫外Fe II类星体的环境
Environments of Strong / Ultrastrong, Ultraviolet Fe II Emitting Quasars
摘要：
利用斯隆数字巡天的DR 7 QSO星表，我们研究了大类星体群（LQG）环境中类星体的紫外Fe II发射强度，并与其他地方的类星体进行了比较，其中1.1 <=<z_LQG><= 1.7。我们使用Weymann等人的W2400等效宽度，定义在静止帧连续窗口2240-2255和2665-2695 Ang之间，作为紫外线Fe II发射的量度。我们发现一个显着的移动W2400分布到更高的值的类星体在LQG，主要是那些LQG与1.1 <=<z_LQG><= 1.5。有一个初步的迹象表明，移动到更高的值与类星体i的星等增加。我们发现的证据表明，在LQGs的超强发射器与W2400 >= 45 Ang。(more准确地说，W2400 >= 44 Ang的超强-plus。与任何W2400强度的相邻类星体相比，最近邻类星体的间距约为30-50 Mpc。对于不在LQG中的超强发射体，没有看到这种效应。增加Fe II发射强度的可能性似乎是铁丰度、Ly-alpha荧光和微湍流，可能所有这些都起作用。LQG的致密环境可能导致恒星形成的速度加快，星系核中铁的丰度增加。类似地，稠密的环境可能导致更活跃的黑洞和增加的Ly-alpha荧光。较强发射体的最佳最近邻分离似乎暗示了一种动力学成分，如微湍流。在一个特殊的LQG中，巨大LQG（早期宇宙中已知的最大结构），七个最强的发射体中有六个非常明显地在总共73个成员中形成三对。
英文摘要：
We have investigated the strength of ultraviolet Fe II emission from quasars within the environments of Large Quasar Groups (LQGs) in comparison with quasars elsewhere, for 1.1 <= <z_LQG> <= 1.7, using the DR7QSO catalogue of the Sloan Digital Sky Survey. We use the Weymann et al. W2400 equivalent width, defined between the rest-frame continuum-windows 2240-2255 and 2665-2695 Ang., as the measure of the UV Fe II emission. We find a significant shift of the W2400 distribution to higher values for quasars within LQGs, predominantly for those LQGs with 1.1 <= <z_LQG> <= 1.5. There is a tentative indication that the shift to higher values increases with the quasar i magnitude. We find evidence that within LQGs the ultrastrong emitters with W2400 >= 45 Ang. (more precisely, ultrastrong-plus with W2400 >= 44 Ang.) have preferred nearest-neighbour separations of ~ 30-50 Mpc to the adjacent quasar of any W2400 strength. No such effect is seen for the ultrastrong emitters that are not in LQGs. The possibilities for increasing the strength of the Fe II emission appear to be iron abundance, Ly-alpha fluorescence, and microturbulence, and probably all of these operate. The dense environment of the LQGs may have led to an increased rate of star formation and an enhanced abundance of iron in the nuclei of galaxies. Similarly the dense environment may have led to more active blackholes and increased Ly-alpha fluorescence. The preferred nearest-neighbour separation for the stronger emitters would appear to suggest a dynamical component, such as microturbulence. In one particular LQG, the Huge-LQG (the largest structure known in the early universe), six of the seven strongest emitters very obviously form three pairings within the total of 73 members.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
