Line shape diagnostics of Galactic 26Al

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dc.creatorKretschmer, K.
dc.creatorDiehl, R.
dc.creatorHartmann, D. H.
dc.date2003-11-10
dc.date.accessioned2026-07-07T02:11:08Z
dc.date.available2026-07-07T02:11:08Z
dc.descriptionThe shape of the gamma-ray line from radioactive 26Al, at 1808.7 keV energy in the frame of the decaying isotope, is determined by its kinematics when it decays, typically 10^6 y after its ejection into the interstellar medium from its nucleosynthesis source. Three measurements of the line width exist: HEAO-C's 1982 value of (0+3) keV FWHM, the GRIS 1996 value of (5.4 +/- 1.3) keV FWHM, and the recent RHESSI value of (2.0 +/- 0.8) keV FWHM, suggesting either "cold", "hot", or "warm" 26Al in the ISM. We model the line width as expected from Galactic rotation, expanding supernova ejecta, and/or Wolf-Rayet winds, and predict a value below 1 keV (FWHM) with plausible assumptions about 26Al initial velocities and expansion history. Even though the recent RHESSI measurement reduces the need to explain a broad line corresponding to 540 km/s mean 26Al velocity through extreme assumptions about grain transport of 26Al or huge interstellar cavities, our results suggest that standard 26Al ejection models produce a line on the narrow side of what is observed by RHESSI and INTEGRAL. Improved INTEGRAL and RHESSI spatially-resolved line width measurements should help to disentangle the effects of Galactic rotation from the ISM trajectories of 26Al.
dc.description5 pages, 4 figures, accepted for publication in A&A
dc.identifierhttps://arxiv.org/abs/astro-ph/0311218
dc.identifierhttp://arxiv.org/abs/astro-ph/0311218
dc.identifierAstron.Astrophys. 412 (2003) L47-L51
dc.identifierdoi:10.1051/0004-6361:20034604
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/6976
dc.subjectAstrophysics
dc.titleLine shape diagnostics of Galactic 26Al
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