Name:	Alatalo, Katherine
Email:	kalatalo@caltech.edu
Institution:	IPAC/Caltech
Title:	Pinpointing Transitioning Galaxies through a New Lens: a Prominent Bifurcation in WISE Colors
Topic:	Discoveries
Abstract:	The onset of large surveys, such as the Sloan Digital Sky Survey, or the WISE All-sky Survey have opened an unprecedented view of the nature of galaxy transitions from the blue cloud to the red sequence, allowing for synergies between these instruments and surveys to emerge. I will present the discovery of the WISE Infrared Transition Zone, a prominent bifurcation in WISE [4.6]-[12] micron colors between early-type and late-type galaxies. This Infrared Transition Zone (IRTZ) is far more prominent than the optical green valley, and seems to represent a different phase in evolution, corresponding to the time when the optical colors have mostly made the transition. I will discuss possible causes for this bifurcation, including the complete exhaustion of the interstellar medium and the presence of active galactic nuclei. This new population of transitioning galaxies, identified by WISE might shed light on later stages in galaxy transition, after the optical colors no longer provide a beacon for these transitioning galaxies, either at late stages of a merger, or through the complete strangulation of the available interstellar medium.