Thursday.
1503.07168
Photon underproduction crisis: are WSOs sufficient to resolve it?
Khaire, Srianand
Investigate the recent claim of 'photon underproduction crisis' by Kollmeier+2014 which suggests that the known sources of UV radiation may not be sufficient to generate the inferred H photoionization rate (Gamma_HI) in the low-z IGM. Using the updated WSO emissivities from the recent studies in the radiative transfer code developed to estimate the UV BG, show that the QSO contribution to Gamma_HI is higher by factor ~2 as compared to the previous estimates. Using self-consistently computed combinations of SFR density and dust attenuation, show that a typical UV scale fraction of 4% from SF galaxies should be sufficient to explain the inferred Gamma_HI by Kollmeier+2014. Interestingly, find that the contribution from WSOs alone can explain the recently inferred Gamma_HI by Shull+2015 which used the same observational at a but different simulation. Therefore, conclude that the crisis is not as severe as it was perceived before and there seems tho need to look for alternative explanations such as low luminosity hidden QSOs or decaying DM particles.
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