0 Assigned ID: 755 ----- Attempting Submission 1 (Fri Apr 07 19:08:01 GMT 2017) ----- HST Phase I Proposal 755 (mcintosh_tidal.apt) successfully submitted. Receipt: # 755-1 ----- Attempting Submission 2 (Fri Apr 07 23:21:32 GMT 2017) ----- HST Phase I Proposal 755 (mcintosh_tidal.apt) failed submission. ----- Attempting Submission 3 (Fri Apr 07 23:21:54 GMT 2017) ----- HST Phase I Proposal 755 (mcintosh_tidal.apt) failed submission. ----- Attempting Submission 4 (Fri Apr 07 23:38:20 GMT 2017) ----- HST Phase I Proposal 755 (mcintosh_tidal.apt) successfully submitted. Receipt: # 755-4 ----- Attempting Submission 5 (Fri Apr 07 23:44:34 GMT 2017) ----- The importance of major merging at z>1 remains in question despite the rapid buildup and development of massive galaxies at these epochs. New theories and observations suggest that non-merging processes like disk instabilities may be even more important than previously thought at assembling bulges, producing clumps, and inducing morphological disturbances that may be misinterpreted as the product of major merging. We propose a novel search for tidal features on a complete sample of nearly 6000 massive z>1 galaxies from CANDELS. Our novel approach will use improved residual maps from multi-component fits to archival WFC3 images, and a new machine learning classification pipeline to robustly identify transient and faint tidal signatures: the hallmark sign of major merging. We will repeat this analysis on synthetic mock images to thoroughly quantify the impacts of cosmological dimming, and calibrate the observability timescale of tidal feature detections. Our study will yield (1) definitive census of massive z>1 galaxies with merger tidal signatures from CANDELS, (2) critically important calibrations for converting tidal detections into merger rates, (3) two novel software pipelines, (4) new stringent tidal-based merger rates that will provide critical tests of theoretical predictions on the relative importance of ex-situ (hierarchical merging) vs. in-situ (gas accretion, cooling, and star formation) assembly of massive galaxies. Galaxies and the IGM 0 Regular false false false SUPPORTED