The Evolution of Luminous Compact Blue Galaxies: Disks or Spheroids?

摘要

Luminous compact blue galaxies (LCBGs) are a diverse class of galaxiescharacterized by high luminosity, blue color, and high surface brightness thatsit at the critical juncture of galaxies evolving from the blue to the redsequence. As part of our multi-wavelength survey of local LCBGs, we have beenstudying the HI content of these galaxies using both single-dish telescopes andinterferometers. Our goals are to determine if single-dish HI observationsrepresent a true measure of the dynamical mass of LCBGs and to look forsignatures of recent interactions that may be triggering star formation inLCBGs. Our data show that while some LCBGs are undergoing interactions, manyappear isolated. While all LCBGs contain HI and show signatures of rotation,the population does not lie on the Tully-Fisher relation nor can it evolve ontoit. Furthermore, the HI maps of many LCBGs show signatures of dynamically hotcomponents, suggesting that we are seeing the formation of a thick disk orspheroid in at least some LCBGs. There is good agreement between the HI andH-alpha kinematics for LCBGs, and both are similar in appearance to the H-alphakinematics of high redshift star-forming galaxies. Our combined data suggestthat star formation in LCBGs is primarily quenched by virial heating,consistent with model predictions.