Detection of gamma-ray lines from interstellar 60Fe by the high resolution spectrometer SPI
Abstract
It is believed that core-collapse supernovae (CCSN), occurring at a rate about once per century, have seeded the interstellar medium with long-lived radioisotopes such as 60Fe (half-life 1.5 Myr), which can be detected by the gamma rays emitted when they beta-decay. Here we report the detection of the 60Fe decay lines at 1173 keV and 1333 keV with fluxes 3.7 +/- 1.1 x 10(-5) ph cm(-2) s(-1) per line, in spectra taken by the SPI spectrometer on board INTEGRAL during its first year. The same analysis applied to the 1809 keV line of 26Al yielded a line flux ratio 60Fe/26Al = 0.11 +/- 0.03. This supports the hypothesis that there is an extra source of 26Al in addition to CCSN.
Keywords
Cite
@article{arxiv.astro-ph/0502219,
title = {Detection of gamma-ray lines from interstellar 60Fe by the high resolution spectrometer SPI},
author = {M. J. Harris and J. Knodlseder and P. Jean and E. Cisana and R. Diehl and G. G. Lichti and J. -P. Roques and S. Schanne and G. Weidenspointner},
journal= {arXiv preprint arXiv:astro-ph/0502219},
year = {2009}
}
Comments
4pp., 5 Figs., accepted by Astronomy & Astrophysics (letter), ref.'s comments included