# ICRC2015

July 29, 2015 to August 6, 2015
World Forum
Europe/Amsterdam timezone

## Observation of the $^{26}Al$ emission distribution throughout the Galaxy with INTEGRAL/SPI

Jul 30, 2015, 3:30 PM
1h
Mississippi Foyer (World Forum)

### Mississippi Foyer

#### World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Board: 111
Poster contribution GA-TH

### Speaker

Dr Laurent Bouchet (IRAP)

### Description

We present $^{26}Al$ map distribution throughout the Galaxy measured by the SPI spectrometer aboard the INTEGRAL observatory. This emission at 1.809 MeV is associated with the $^{26}Al$ decay and to the production of heavy elements in the Galaxy. The only available $^{26}Al$ map to date has been released, more than fifteen years ago, thanks to the COMPTEL instrument. However, at the present time, SPI offers a unique opportunity to enrich this first result. The data accumulated between 2003 and 2013 which amounts to 2$\times$ 10$^{8}$ s of observing time are used to perform a dedicated analysis, aiming to deeply investigate the spatial morphology of the $^{26}Al$ emission. The data are first compared with several sky maps based on observations at various wavelengths to model the $^{26}Al$ distribution throughout the Galaxy. For most of the distribution models, the inner Galaxy flux is compatible with a value of 3.3$\times$ 10$^{-4}$ ph. cm$^{-2}$.s$^{-1}$ while the preferred template maps correspond to young stellar components such as core-collapse supernovae, Wolf-Rayet and massive AGB stars. To get more details about this emission, an image reconstruction is performed using an algorithm based on the maximum-entropy method. In addition to the inner Galaxy emission, several excesses suggest that some sites of emission are linked to the spiral arms structure. Lastly, an estimation of the $^{56}Fe$ line flux, assuming a spatial distribution similar to $^{26}Al$ line emission, results in a $^{56}Fe$ to $^{26}Al$ ratio around 0.14, which agrees with the most recent studies and with the SN explosion model predictions.
Collaboration -- not specified -- 114

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