Using a sample of nine massive compact galaxies at z \sim 2.3 with rest-frame optical spectroscopy and comprehensive U \rightarrow 8 \micron photometry we investigate how assumptions in SED modeling change the stellar mass estimates of these galaxies , and how this affects our interpretation of their size evolution .
The SEDs are fit to \tau -models with a range of metallicities , dust laws , as well as different stellar population synthesis codes .
These models indicate masses equal to , or slightly smaller than our default masses .
The maximum difference is 0.16 dex for each parameter considered , and only 0.18 dex for the most extreme combination of parameters .
Two-component populations with a maximally old stellar population superposed with a young component provide reasonable fits to these SEDs using the models of Bruzual & Charlot ( 2003 ) ; however , using models with updated treatment of TP-AGB stars the fits are poorer .
The two-component models predict masses that are 0.08 to 0.22 dex larger than the \tau -models .
We also test the effect of a bottom-light IMF and find that it would reduce the masses of these galaxies by 0.3 dex .
Considering the range of allowable masses from the \tau -models , two-component fits , and IMF , we conclude that on average these galaxies lie below the mass-size relation of galaxies in the local universe by a factor of 3-9 , depending on the SED models used .