J. C. Mather et al. 1999 ApJ 512 511 doi:10.1086/306805
J. C. Mather1, D. J. Fixsen2, R. A. Shafer1, C. Mosier1 and D. T. Wilkinson3
Show affiliationsThe photometric errors of the external calibrator for the Far Infrared Absolute Spectrophotometer (FIRAS) instrument on the COBE are smaller than the measurement errors on the cosmic microwave background radiation (CMBR) spectrum (typically 0.02 MJy sr-1, 1 σ) and smaller than 0.01% of the peak brightness of the CMB. The calibrator is a reentrant cone, shaped like a trumpet mute, made of Eccosorb iron-loaded epoxy. It fills the entire beam of the instrument and is the source of its accuracy. Its known errors are caused by reflections, temperature gradients, and leakage through the material and around the edge. Estimates and limits are given for all known error sources. Improvements in understanding the temperature measurements of the calibrator allow an improved CMB temperature determination of 2.725±0.002 K.
cosmic microwave background; cosmology: observations; instrumentation: spectrographs
Issue 2 (1999 February 20)
Received 1998 June 5, accepted for publication 1998 September 28
J. C. Mather et al. 1999 ApJ 512 511
N V Agudov et al 2004 J. Phys. A: Math. Gen. 37 5279
K Andrae et al 2002 J. Phys. B: At. Mol. Opt. Phys. 35 4203
I Bray et al 2002 J. Phys. B: At. Mol. Opt. Phys. 35 R117
Ali H Nayfeh and Mohammad I Younis 2005 J. Micromech. Microeng. 15 1840
S J Antony et al 2005 J. Phys. D: Appl. Phys. 38 3944
Michiel R. Hogerheijde et al. 1999 ApJ 513 350
Robert C. Kennicutt, Jr. 1998 ApJ 498 541
T May et al 2003 Supercond. Sci. Technol. 16 1430
T. K. Sridharan et al. 2002 ApJ 566 931