Several recent studies find that 10 – 50 % of morphologically selected field early-type galaxies at redshifts z \lesssim 1 have blue colors indicative of recent star formation .
Such ‘ ‘ blue spheroids ’ ’ might be massive early-type galaxies with active star formation , perhaps induced by recent merger events .
Alternatively , they could be starbursting , low-mass spheroids .
To distinguish between these two choices , we have selected 10 ‘ ‘ Blue Spheroid Candidates ’ ’ Throughout this paper , ‘ ‘ spheroids ’ ’ are defined as featureless galaxies which include Es , S0s , and dEs , while bulges of spiral galaxies are not included . ( hereafter , BSCs ) from a quantitatively selected E/S0 sample to study their properties , including kinematics from Keck spectra obtained as part of the DEEP Groth Strip Survey ( GSS ) .
Most BSCs ( 70 % ) turn out to belong to two broad categories , while the remaining objects are likely to be misclassified objects .
Type-1 BSCs have underlying red stellar components with bluer inner components .
Type-2 BSCs do not show an obvious sign of the underlying red stellar component , and their overall colors are quite blue ( ( U - B ) _ { rest } < 0 ) .
Both Type-1 and Type-2 BSCs have internal velocity dispersions measured from emission lines \sigma \lesssim 80 km sec ^ { -1 } and estimated dynamical masses of only a few \times 10 ^ { 10 } M _ { \sun } or less .
For Type-1 BSCs , we estimate \sigma of the red component using the fundamental plane relation of distant field absorption-line galaxies and find that these \sigma estimates are similar to the \sigma measured from emission lines .
Overall , we conclude that our Type-1 and Type-2 BSCs are more likely to be star-forming low mass spheroids than star-forming , massive , early-type galaxies .