HST/ACS SnapShot Imaging of 29 Post-Starburst Quasars

We present quantitative host galaxy measurements of 29 post-starburst quasars (PSQs) from a Hubble Space Telescope (HST ) Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) Snapshot program. PSQs are broad-lined AGN that also possess the spectral signatures of massive, moderate-aged stellar populations (in excess of ten billion solar masses and ages of hundreds of Myrs). Thus, these objects could represent a key phase in galaxy evolution from spiral to elliptical. We explore the morphologies, bulge luminosities and quasar to host galaxy light contributions via twodimensional image analysis of the PSF subtracted images. We look for trends between the host galaxy measurements and the morphology classifications. The HST/ACSF606W (broad V-band at 0.05”/pixel) SNAP images show that while some of the PSQs are obviously quasars living in spiral galaxies, others appear to be disturbed ellipticals inviting us to classify the PSQs as undisturbed spirals, merger or post-merger events. In two of the images we see obvious merging and about 40% have neighbors within 10′′. The vast majority of systems show signs of interaction/merger activity, such as, tidal tails, shells, star-forming knots and asymmetries. These results are consistent with merging scenarios which build larger elliptical galaxies via mergers of smaller spiral ones.