In this article I briefly describe how deep radio surveys may provide a means to identify variations in the upper end of the initial mass function (IMF) in star-forming galaxies at high redshifts (i.e., z≳3). At such high redshifts, I argue that deep radio continuum observations at frequencies ≳10 GHz using next generation facilities (e.g., EVLA, MeerKAT, SKA/NAA) will likely provide the most accurate measurements for the ionizing photon rates (star formation rates; SFRs) of normal galaxies since their non-thermal emission should be highly suppressed due to the increased inverse Compton (IC) losses from the cosmic microwave background (CMB), leaving only thermal (free-free) emission detectable. Thus, a careful analysis of such observations in combination with future ALMA and JWST data, measuring the rest-frame far-infrared and UV emission from the same population of galaxies, may yield the best means to search for variability in the stellar IMF at such epochs.
@article{arxiv.1009.1666,
title = {Identifying Variations to the IMF at High-$z$ Through Deep Radio Surveys},
author = {Eric J. Murphy},
journal= {arXiv preprint arXiv:1009.1666},
year = {2010}
}
Comments
8 pages, 4 figures; to be published in "UP: Have Observations Revealed a Variable Upper End of the Initial Mass Function?", M. Treyer, J.C. Lee, M.H. Seibert, T. Wyder, & J. Neil, eds