Fixsen 2009 ARCADE 2对河外天区的温度测量

主要内容:
在3.3GHz处, 比CMB的2.73K多了0.05K.
整体上有一个额外的比2.73K黑体辐射多出的温度 T=1.26K (nu/1GHz)^-2.6, 其中nu=(22MHz,10GHz).

那么: 如果换成流量, 根据F_nu\propto T nu^2 \propto nu^-0.6 ~ nu^-1/2. 像是某种冷却啊.

精彩摘抄:


文章信息:
ARCADE 2 Measurement of the Extra-Galactic Sky Temperature at 3-90 GHz

Authors: D. J. Fixsen, A. Kogut, S. Levin, M. Limon, P. Lubin, P. Mirel, M. Seiffert, J. Singal, E. Wollack, T. Villela, C. A. Wuensche

(Submitted on 5 Jan 2009)

Abstract: The ARCADE 2 instrument has measured the absolute temperature of the sky at frequencies 3, 8, 10, 30, and 90 GHz, using an open-aperture cryogenic instrument observing at balloon altitudes with no emissive windows between the beam-forming optics and the sky. An external blackbody calibrator provides an {\it in situ} reference. Systematic errors were greatly reduced by using differential radiometers and cooling all critical components to physical temperatures approximating the CMB temperature. A linear model is used to compare the output of each radiometer to a set of thermometers on the instrument. Small corrections are made for the residual emission from the flight train, balloon, atmosphere, and foreground Galactic emission. The ARCADE 2 data alone show an extragalactic rise of $50\pm7$ mK at 3.3 GHz in addition to a CMB temperature of $2.730\pm .004$ K. Combining the ARCADE 2 data with data from the literature shows a background power law spectrum of $T=1.26\pm 0.09$ [K] $(\nu/\nu_0)^{-2.60\pm 0.04}$ from 22 MHz to 10 GHz ($\nu_0=1$ GHz) in addition to a CMB temperature of $2.725\pm .001$ K.

Comments:	11 pages 5 figures Submitted to ApJ
Subjects:	Astrophysics (astro-ph)
Cite as:	arXiv:0901.0555v1 [astro-ph]