NXS Observing at KPNO March/April 2009 [4m 05B-0045 run Mar 25-Apr 1, 2009]

测量来自XCS星系团调查的大约50个候选X射线星系团的光度学红移。这是国家海洋和大气局4M望远镜(CTIO和KPNO)上的NXS项目(总共40个晚上)的最终分配时间(8个晚上)。XCS是由苏塞克斯大学的凯西·罗默博士领导的一个国际合作项目。XCS的目标是找到XMM卫星在其10年寿命内意外探测到的所有X射线星团，然后用它们来解决银河系外天文学和宇宙学中的各种科学问题。NXS的数据正在由苏塞克斯大学由STFC资助的博士生尼古拉·梅尔滕斯处理。她发现，红移可以使用图像以一种稳健的方式测量，而不是更传统、更耗时的光谱分析方法。通过将NXS成像与XMM提供的X射线数据相结合，我们能够得出各种科学结论。这些结论的范围从星系在大质量星系团中演化的方式到基本宇宙学参数的测量(包括暗能量的能量密度)。NXS项目是一项重大的国际努力，跨越了3年和8次望远镜活动。最后一次战役由NOAO授予NXS，以补偿前一次运行中的仪器问题。这给了我们一个独特的机会来完成我们星团样本在天空中特别丰富的区域的红移覆盖(在这次运行中可以看到北银河系的盖子)。

To measure photometric redshifts for about 50 X-ray cluster candidates from the XCS cluster survey. This is the final allocation of time (8 nights) for the NXS project (40 nights total) on NOAO 4m telescopes (CTIO and KPNO). XCS is a international collaboration led by Dr Kathy Romer at the University of Sussex. XCS aims to find all the X-ray clusters detected by accident by the XMM satellite during its 10 year lifespan, and then to use them to attack a variety of science questions in extra galactic astronomy and cosmology. The NXS data are being processed by an STFC supported PhD student at the University of Sussex, Nicola Mehrtens. She has found that redshifts can be measured in a robust way using images, rather than the more traditional - and time consuming - spectroscopy method. Through the combination of the NXS imaging with X-ray data available from the XMM, we are able to make a variety of scientific conclusions. These conclusions range from the way galaxies evolve in massive clusters to measurements of fundamental cosmological parameters (including the energy density of dark energy). The NXS project has been a major international endeavor, spanning 3 years and 8 telescope campaigns. The final campaign was awarded to NXS by NOAO to compensate for instrument problems during a previous run. It gives us a unique opportunity to complete the redshift coverage for our cluster sample in a particularly rich region of the sky (the North Galactic cap is visible during this run).