EDP Sciences
Free access
Volume 499, Number 3, June I 2009
Page(s) 661 - 667
Section Cosmology (including clusters of galaxies)
DOI http://dx.doi.org/10.1051/0004-6361/200811272
Published online 27 March 2009
A&A 499, 661-667 (2009)
DOI: 10.1051/0004-6361/200811272

Analytic fitting formulae for relativistic electron-electron thermal bremsstrahlung

S. Nozawa1, K. Takahashi2, Y. Kohyama2, and N. Itoh2

1  Josai Junior College, 1-1 Keyakidai, Sakado-shi, Saitama, 350-0295, Japan
    e-mail: snozawa@josai.ac.jp
2  Department of Physics, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo, 102-8554, Japan
    e-mail: n_itoh@sophia.ac.jp

Received 1 November 2008 / Accepted 18 February 2009

We present accurate analytic fitting formulae for electron-electron thermal bremsstrahlung emissivity. The fitting formulae have an overall accuracy of higher than 0.5% for a wide electron temperature range 1 keV $\leq$ $k_{\rm B}T$ $\leq$ 7 MeV, which will be useful when analyzing the precision observational data from the non-relativistic regime to mildly-relativistic regime. Assuming the thermal plasma, the present formulae will be also applicable to the relativistic regime.

Key words: cosmology: theory -- galaxies: clusters: general -- radiation mechanisms: thermal -- relativity -- X-rays: galaxies: clusters

© ESO 2009