Constraining the IMF using TeV gamma ray absorption
Abstract
Gamma rays from distant sources suffer attenuation due to pair production off of ∼ 1 μm extragalactic background light (EBL) photons via γγ → e+e- (R.J. Gould, G.P. Schréder, Phys. Rev. 155 (1967) 1404). The cross section for the pair production is maximized just above threshold, when λ EBL ∼ ( E γ/TeV) μ m. We may exploit this process in order to indirectly measure the EBL, and constrain models of galaxy formation. Here, using semi-analytic models of galaxy formation, we examine how gamma ray absorption may be used as an indirect probe of the stellar initial mass function (IMF), although there is a degeneracy with dust modeling. We point out that with the new generation of gamma ray telescopes including STACEE, MAGIC, HESS, VERITAS, and Milagro, we should soon possess a wealth of new data and a new method for probing the nature of the IMF.
- Publication:
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Astroparticle Physics
- Pub Date:
- June 1999
- DOI:
- 10.1016/S0927-6505(99)00033-X
- arXiv:
- arXiv:astro-ph/9812370
- Bibcode:
- 1999APh....11..111B
- Keywords:
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- Astrophysics
- E-Print:
- contribution to "TeV Astrophysics of Extragalactic Sources" VERITAS workshop, editors M. Catanese, J. Quinn, T. Weekes