Nucleosynthesis in the Vela region

Lavraud, B.; Knödlseder, J.; Cerviño, M.; von Ballmoos, P.; Schaerer, D.
Bibliographical reference

In: Exploring the gamma-ray universe. Proceedings of the Fourth INTEGRAL Workshop, 4-8 September 2000, Alicante, Spain. Editor: B. Battrick, Scientific editors: A. Gimenez, V. Reglero & C. Winkler. ESA SP-459, Noordwijk: ESA Publications Division, ISBN 92-9092-677-5, 2001, p. 79 - 82

Advertised on:
9
2001
Number of authors
5
IAC number of authors
0
Citations
2
Refereed citations
2
Description
The detection of 1.809 MeV gamma-ray line emission from the Vela region by the COMPTEL telescope presents a direct prove of recent nucleosynthesis activity in this region. It has been suggested that the observed 1.809 MeV emisson could arise from the radioactive decay of 26Al produced by the Vela SNR and/or the nearby Wolf-Rayet star γ2 Vel. However, the recent analysis of COMPTEL data render these hypotheses rather unlikely. We propose an alternative scenario to explain the observed 1.809 MeV emisson where 26Al is produced by the combined activity of massive stars in the Vela region. Using an evolutionary synthesis model we calculate the expected multi-wavelength spectrum from the Vela region based on the known massive star population. We estimate a 1.809 MeV flux of (3 - 11)10-6 ph cm-2s-1 from the region of Vela (250° < l < 280° -15° < b < 15°). This value compares to (29+/-6)10-6 ph cm-2s-1 as derived by Oberlack (1997) from COMPTEL data. Our underestimation by a factor between 2 - 10 may stem from the lack of known OB stars and associations in this region. Based on our modelling effort, we explore the scientific potential of future observation of the Vela region by the INTEGRAL observatory.