The shakeup emission spectrum in a two-dimensional electron gas in a strong magnetic field is calculated analytically. The case of a localized photocreated hole is studied and the calculations are performed with a Nozieres-De Dominicis-like Hamiltonian. The hole potential is assumed to be small compared to the cyclotron energy and is therefore treated as a perturbation. Two competing many-body effects, the shakeup of the electron gas in the optical transition, and the excitonic effect, contribute to the shakeup satellite intensities. It is shown, that the range of the hole potential essentially influences the shakeup spectrum. For a short range interaction the above mentioned competition is more important and results in the shakeup emission quenching when electrons occupy only the lowest Landau level. When more than one Landau level is filled, the intensities of the shakeup satellites change with magnetic field nonmonotonically. If the interaction is long range, the Fermi sea shakeup processes dominate. Then, the satellite intensities smoothly decrease when the magnetic field increases and there is no suppression of the shakeup spectrum when the only lowest Landau level is filled. It is shown also that a strong hole localization is not a necessary condition for the SU spectrum to be observed. If the hole localization length is not small compared to the magnetic length, the SU spectrum still exists. Only the number of contributions to the SU spectrum reduces and the shakeup processes are always dominant.
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