Simulation of the Galactic 1.809 MeV ^26Al Gamma-Ray Flux

Session 48 - Gamma Rays & X-ray Instrumentation.
Display session, Thursday, January 08
Exhibit Hall,

[48.04] Simulation of the Galactic 1.809 MeV ^26Al Gamma-Ray Flux

E. J. Lentz, D. Branch, E. Baron (U. Oklahoma)

The observed map of 1.809 MeV gamma-rays from radioactive ^26Al (Oberlack et al, 1996, Aamp;AS, 120, 311) shows clear evidence of a Galactic plane origin with an uneven distribution. We have simulated the map using a Monte Carlo technique together with simple assumptions about the spatial distributions and yields of ^26Al sources (clustered core-collapse supernovae and Wolf Rayet stars; low- and high-mass AGB stars; and novae). Although observed structures (e.g., tangents to spiral arms, bars, and known star-forming regions) are not included in the model, our simulated gamma-ray distribution bears resemblance to the observed distribution. The major difference is that the model distribution has a strong smooth background along the Galactic plane from distant sources in the disk of the Galaxy. We suggest that the smooth background is to be expected, and probably has been suppressed by the maximum entropy technique used to make the observed map.

Program listing for Thursday