Spectral and intensity variations of Galactic 26^Al emission

Abstract

Gamma-ray line emission from the radioactive decay of 26Al reflects nucleosynthesis in massive stars and supernovae. We use INTEGRAL 26Al measurements to characterize the distribution and characteristics of 26Al source regions throughout the Galaxy. We detect the 26Al line from the inner Galaxy at 28σsignificance. The line appears narrow, and we constrain broadening in the source regions to <1.3 keV (2σ). Different sky distribution models do not significantly affect those large-scale results. The 26Al intensity for the inner Galaxy is derived as (2.9\pm 0.2)\times 10^{-4}ph\ cm^{-2} s^{-1} rad^{-1}, consistent with earlier results from COMPTEL and SPI data. This can be translated to an 26Al mass of 2.7\pm 0.7 solar mass in the Galaxy as a whole. The 26Al intensity is also confirmed to be somewhat brighter in the 4th than in the 1st quadrant (ratio 1.3\pm 0.2). 26Al spectra separately derived for regions along the Galactic plane show clear line centroid shifts, attributed largely to the Galaxy's large-scale rotation. The 26Al line toward the direction of the Aquila region (20deg < l < 40deg) appears somewhat broadened. Latitudinal variations of 26Al emission towards the inner Galaxy are studied, finding a latitudinal scale height of 130^{+120}_{-70} pc (1σ) for 26Al in the inner Galaxy and a hint of peculiar 26Al emission towards the region l<0deg, b>5deg.

13 pages, 12 figures, accepted for the publication in A&A

References in corpus (7)

• Nucleosynthesis and Remnants in Massive Stars of Solar Metallicity
• The nucleosynthesis of Al26 and Fe60 in solar metallicity stars extending in mass from 11 to 120 Msun: the hydrostatic and explosive contributions
• Gamma-ray continuum emission from the inner Galactic region as observed with INTEGRAL/SPI
• Star formation in isolated AMIGA galaxies: dynamical influence of bars
• The large scale dust lanes of the Galactic bar
• An Association in the Aquila Star-Forming Region: High Resolution Infrared Spectroscopy of T Tauri Stars
• Line shape diagnostics of Galactic 26Al

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