Presentation #136.05 in the session Dwarf Galaxies: Theoretical Predictions and Nearby Universe.
The evolution of galaxies is known to be driven by mass and environment, where the role of the latter is expected to be more acute for dwarf galaxies due to their shallow potential wells. Along these lines, the conventional paradigm of dwarf galaxy evolution in massive galaxy clusters posits that flocculent, gas-rich, mildly star-forming dwarf irregulars (dIrrs) are transformed into smooth, gas-poor, quiescent dwarf ellipticals (dEs) after infall due to rapid depletion of their cold gas reservoirs by external forces like ram pressure stripping. However, recent work based on numerical simulations suggest that dwarfs that were accreted into clusters at high redshift experienced a more concentrated and bursty star formation history due to a combination of galaxy assembly bias and environmentally-induced starbursts. This suggestion has found some observational support via cluster-centric trends in the richness of globular cluster systems around dE galaxies in the Virgo and Fornax clusters. Another way to test numerical simulations is to diagnose the ages and chemical abundances of such galaxies in the same environments, but current samples of blue-optical spectroscopy are too small in size and/or have too low signal-to-noise. In this talk, I will outline a campaign we have initiated through Gemini and Keck (with the GMOS and KCWI IFUs, respectively) to amass blue-optical spectroscopy for a large and representative sample of dE’s in the Virgo cluster, drawing on both archival datasets and new observations. Attention will be paid to our sample selection function, the integrated spectra extracted from our data cubes, the use of full spectrum modelling to characterize the stellar populations, initial results on the ages and alpha-abundances of our targets, and possible synergies with previous (long-slit) spectroscopic surveys of the Virgo cluster.