2005/02/09 by Makoto Hattori, Nobuhiro Okabe
Physics and Astronomy · #Cosmology and Gravitation Theories #Radio Astronomy Observations and Technology #Superconducting and THz Device Technology #astro-ph
paper · pdf · doi:10.1086/429576
published as Astrophys.J. 625 (2005) 741-747 · 18pages, 3figures, accepted for publication in ApJ
arxiv created 2005/02/09 · openalex publication_date 2005/05/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
The inverse Compton scattering of the cosmic microwave background (CMB) radiation with electrons in the intracluster medium, which has a temperature gradient, is examined using third-order perturbation theory of Compton scattering. A new type of spectrum distortion of the CMB was found and named the gradient- T Sunyaev-Zel'dovich effect (grad- T SZE). The spectrum has a universal shape. The spectrum crosses zero at 326 GHz. The sign of the spectrum depends on the relative direction of the line of sight to the direction of the temperature gradient. This unique spectrum shape can be used to detect the grad- T SZE signal by broadband or multifrequency observations of the SZE. The amplitude of the spectrum distortion does not depend on the electron density and is proportional to the heat conductivity. Therefore, the grad- T SZE provides a unique opportunity to measure the thermally nonequilibrium electron momentum distribution function when the ICM has a temperature gradient and a heat conductivity in the ICM. However, the expected amplitude of the signal is very small. The modifications to the thermal SZE spectrum due to a variety of known effects, such as relativistic correction, can become problematic when using multifrequency separation techniques to detect the grad- T SZE signal.