AKARI OBSERVATION OF THE FLUCTUATION OF THE NEAR-INFRARED BACKGROUND
AKARI OBSERVATION OF THE FLUCTUATION OF THE NEAR-INFRARED BACKGROUND
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DOI：
10.1088/0004-637x/742/2/124
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发表时间：
2010-10
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通讯作者：
T. Matsumoto;T. Matsumoto;H. Seo;W. Jeong;Ho-Gyu Lee;Shuji Matsuura;H. Matsuhara;S. Oyabu;S. Oyabu;J. Pyo;T. Wada
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作者：
T. Matsumoto;T. Matsumoto;H. Seo;W. Jeong;Ho-Gyu Lee;Shuji Matsuura;H. Matsuhara;S. Oyabu;S. Oyabu;J. Pyo;T. Wada
本文报道了用日本红外天文卫星AKARI在2.4、3.2和4.1 μm波段对黄道北极附近天空亮度波动的研究。我们得到了直径为10′的圆形图，它清楚地显示了几百角秒尺度的空间结构。功率谱分析表明，在大于100″的角标度上有一个显著的过量波动，这不能用黄道光、漫射银河光、微弱星系的散粒噪声或低红移星系的聚集来解释。这些结果与NASA斯皮策太空望远镜在3.6和4.5 μm处的观测结果一致。在大角度尺度上观测到的波动成分具有蓝色恒星光谱，这与空间红外望远镜观测到的过量各向同性发射光谱相似。发现波段之间存在显着的空间相关性，并且线性相关性的斜率与超额波动的光谱一致。这些发现表明，探测到的波动可以归因于宇宙的第一批恒星，即，星族III星。观察到的波动为第一颗恒星的时代提供了重要的约束。
We report a search for fluctuations of the sky brightness toward the north ecliptic pole with the Japanese infrared astronomical satellite AKARI, at 2.4, 3.2, and 4.1 μm. We obtained circular maps with 10′ diameter fields of view, which clearly show a spatial structure on the scale of a few hundred arcseconds. A power spectrum analysis shows that there is a significant excess fluctuation at angular scales larger than 100″ that cannot be explained by zodiacal light, diffuse Galactic light, shot noise of faint galaxies, or clustering of low-redshift galaxies. These results are consistent with observations at 3.6 and 4.5 μm by NASA's Spitzer Space Telescope. The fluctuating component observed at large angular scales has a blue stellar spectrum which is similar to that of the spectrum of the excess isotropic emission observed with the Infrared Telescope in Space. A significant spatial correlation between wavelength bands was found, and the slopes of the linear correlations are consistent with the spectrum of the excess fluctuation. These findings indicate that the detected fluctuation could be attributed to the first stars of the universe, i.e., Population III stars. The observed fluctuation provides an important constraint on the era of the first stars.