Using "BlueBRD" Galaxies to Quantify Quenching

University Of Washington, Seattle WA

Investigators

Abstract

Understanding the interactions between gas and star formation are central in understanding how galaxies evolve. According to current models, galaxies grow in dark matter halos. At early times a galaxy's baryonic growth tracks its dark matter growth, and galaxies grow from the inside-out. In this model, one expects bulges of galaxies to be old and red, while the disk is young and blue, especially during galaxy growth. The investigators have discovered a population of galaxies that should not exist within this framework. These galaxies, named BlueBRD galaxies, appear to be centrally forming stars in their bulge while star formation in the disk has ceased. The investigators will combine observations and simulated galaxy data to understand the nature of these galaxies. This project will also pilot University-wide mentorship for postdoctoral researchers and faculty members to develop departments that are inclusive and welcoming, and grounded in respect and equality. The current models of galaxy evolution posit that at early times a galaxy's baryonic growth tracks its dark matter growth and that galaxies grow from the inside-out. The investigators have identified a population of galaxies that should not exist within this framework. These galaxies appear to be centrally forming stars while star formation in the disk has ceased. The investigators will combine observations and simulated galaxy data to clarify the nature of these galaxies. The galaxies are currently being observed with optical integral field spectroscopy to spatially resolve star formation throughout the galaxy. These observations will be combined with molecular gas observations and HI neutral gas observations from ongoing surveys to identify the location of gas reserves. If star formation has been quenched throughout the disk, it is expected that the gas reservoirs will be depleted or absent. This understanding will help to identify galaxies where star formation might be influenced by the galaxy environment. This project will also pilot a mentorship project across the University for postdoctoral researchers and faculty members to develop departments that are inclusive and welcoming. As recent studies have shown, department climate sets the tone and often creates and protects harassers. This project will build a community committed to mentoring grounded in respect and equality. The project will focus on the effects of conscious and unconscious bias, and it will develop individual and departmental actions that will promote an equitable academic environment. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.