Cosmic infrared background (CIB) contains emission from epochs inaccessible to current telescopic studies, such as the era of the first stars. We discuss theoretical expectations for the CIB contributions from the early population of massive stars. We then present the latest results from the ongoing project by our team (Kashlinsky, Arendt, Mather & Moseley 2005,2007a,b,c,) to measure CIB fluctuations from early epochs using deep Spitzer data. The results show the existence of significant CIB fluctuations at the IRAC wavelengths (3.6 to 8 mic) which remain after removing galaxies down to very faint levels. These fluctuations must arise from populations that have a significant clustering component, but only low levels of the shot noise. Furthermore, there are no correlations between the source-subtracted IRAC maps and the corresponding fields observed with the HST ACS at optical wavelengths. Taken together, these data imply that 1) the sources producing the CIB fluctuations are individually faint with flux < a few nJy at 3.6 and 4.5 mic; 2) are located within the first 0.7 Gyr (unless these fluctuations can somehow be produced by - so far unobserved - local galaxies of extremely low luminosity and with the unusual for local populations clustering pattern), 3) they produce contribution to the net CIB flux of at least 1-2 nW/m^2/sr at 3.6 and 4.5 mic and must have mass-to-light ratio significantly below the present-day populations, and 4) they have angular density of ~ a few per arcsec^2 and are in the confusion of the present day instruments, but can be individually observable with JWST.
Searching for the first galaxies through gravitational lenses
观测在再电离时期形成的第一个星系，即大约在大爆炸后的第一个十亿年内，仍然是当代天体物理学的挑战之一。目前正在作出若干努力来寻找这种遥远的物体。结合VLT的近红外成像能力和强引力透镜的自然效应，我们的试验计划使我们能够识别几个红移为6 <~ z <~ 10的候选星系。这些对象的属性和由此产生的限制在高红移的恒星形成率密度进行了讨论。最后，我们提出了后续观测（ISAAC光谱，HST和斯皮策成像）的状态，并讨论了未来的发展。
On using visibility correlations to probe the HI distribution from the dark ages to the present epoch I: Formalism and the expected signal
在低频射电观测中，来自中性氢（HI）宇宙学分布的红移21厘米辐射是一种背景辐射。这种辐射中的角域和频域波动携带着宇宙结构形成的信息。我们建议，在不同的基线和频率在无线电干涉观测测量的波动之间的相关性被用来量化这些波动的统计特性。这有一个固有的优势，在其他统计估计，它直接处理的vibrations这是在无线电干涉观测测量的主要数量。可见度相关性与功率谱有简单的关系。我们目前估计的预期信号几乎整个后重组时代，从黑暗时代到现在的时代。在HI呈片状分布的再电离时期，信号由离散电离区域的大小决定，具有明显的特征。在HI跟随暗物质的其他时期，信号很大程度上取决于暗物质波动的功率谱。对于天线间隔在观测波长的几百倍内的基线，信号是最强的，并且最佳策略将优先对这些基线进行采样。在频域中，对于大多数基线，两个不同频率处的Vibrations在Δ v ~ 1 MHz之外是不相关的，原则上这一特征将允许HI信号容易地与连续污染源区分开。
