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arXiv 1202.4049astro-ph.COastro-ph.EP
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北极地区AKARI观测的中红外天空亮度和起伏

Brightness and Fluctuation of the Mid-Infrared Sky from AKARI Observations towards the North Ecliptic Pole

Jeonghyun Pyo, Toshio Matsumoto, Woong-Seob Jeong, Shuji Matsuura

摘要:

我们提出了平滑的中红外天空的观测日本红外天文卫星AKARI。AKARI在其冷相期间用覆盖2.4至24微米的9个波段监测了北黄道极(NEP),其中6个中红外波段用于本研究。我们应用功率谱分析的图像,以寻找天空亮度的波动。观测到的波动被解释为光子噪声,微弱源的散粒噪声和银河卷云的波动。在短的中红外波长(7,9和11微米)的几角分尺度的波动主要是由星际尘埃卷云的漫射银河光引起的。在长的中红外波长(15,18和24微米),光子噪声是波动的主要来源,从弧秒到几个弧分。去除这些影响后,200弧秒处的剩余波动幅度在24微米处至多为1.04 +/- 0.23 nW m^-2 sr^-1或亮度的0.05%,在18微米处至少为0.47 +/- 0.14 nW m^-2 sr^-1或亮度的0.02%。我们得出,考虑2σ误差时,黄道光向NEP方向的波动上限为天空亮度的0.03%。

英文摘要:

We present the smoothness of the mid-infrared sky from observations by the Japanese infrared astronomical satellite AKARI. AKARI monitored the north ecliptic pole (NEP) during its cold phase with nine wavebands covering from 2.4 to 24 micron, out of which six mid-infrared bands were used in this study. We applied power spectrum analysis to the images in order to search for the fluctuation of the sky brightness. Observed fluctuation is explained by fluctuation of photon noise, shot noise of faint sources, and Galactic cirrus. The fluctuations at a few arcminutes scales at short mid-infrared wavelengths (7, 9, and 11 micron) are largely caused by the diffuse Galactic light of the interstellar dust cirrus. At long mid-infrared wavelengths (15, 18, and 24 micron), photon noise is the dominant source of fluctuation over the scale from arcseconds to a few arcminutes. The residual fluctuation amplitude at 200 arcseconds after removing these contributions is at most 1.04 +/- 0.23 nW m^-2 sr^-1 or 0.05% of the brightness at 24 micron and at least 0.47 +/- 0.14 nW m^-2 sr^-1 or 0.02% at 18 micron. We conclude that the upper limit of the fluctuation in the zodiacal light towards the NEP is 0.03% of the sky brightness, taking 2σ error into account.

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。

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