Apr 13, 2017
Angie Van Sistine, UW Milwaukee
"The Local Universe in Hα"
Both the ALFALFA Hα and iPTF Hα Surveys map the local universe using Hα. The ALFALFA Hα survey uses a volume-limited sample of HI-selected galaxies from the ALFALFA survey to study star formation in the local universe. By selecting galaxies via their HI emission, ALFALFA Hα includes essentially every galaxy capable of making stars in our survey volume. We have obtained sensitive narrow-band Hα images for this large sample of >1500 galaxies. The ALFALFA Hα survey's large, complete sample of galaxies gives us robust statistics and allows us to cover a wide range of galaxian environments. I will present an overview of the survey and results based on both our fall and spring samples.
The iPTF Hα Survey is a blind survey of 3π of the sky utilizing narrowband filters to detect Hα emission out to 200 Mpc. The final data will include 3 exposures per pointing and will be the largest Hα narrowband survey of the sky to date. Using only the single-exposure data and conservative galaxy selection techniques, this survey yields a galaxy sample that is deeper than the SDSS spectroscopic galaxy survey. The iPTF Hα Survey will discover 10s-of-thousands of new galaxies in our volume and contributes to the Census of the Local Universe (CLU). CLU aims to catalog all galaxies within 200 Mpc with a primary goal of aiding in the electromagnetic follow-up of gravitational wave detections. In this talk, I will describe iPTF Hα, CLU, and our ongoing projects.