BUILDING THE MOST ROBUST CATALOG OF VOIDS AND VOID GALAXIES

Simulations and observations of the geometrical distribution of galaxies in the universe reveal a web-like structure where galaxies inhabit the so-called filaments, or walls, which surround extremely under-dense regions, called the cosmic voids. Interestingly, these regions, largely devoid of galaxies, occupy half of the volume of the universe. Because of their sparseness, interactions of galaxies in voids are significantly less likely than in denser regions, suggesting strong differences in their evolutionary paths relative to galaxies in walls. Current efforts in identifying voids and void galaxies in a manner that is model independent remain controversial. With this work we analyze and compare the most current algorithms for finding these structures with the aim of building the largest and best defined catalog of voids and their inhabitants. We use the largest galaxy catalog to date, the Sloan Digital Sky Survey Data Release 7, to test a variety of proposed number densities, volumes, and shapes of under-dense regions, and quantify the differences between them. The final product of this investigation will be used with multi-wavelength observations of both void and wall galaxies to constrain environmental differences in the strength and type of accretion onto galactic supermassive black holes, the star formation activity, and the interplay between them, at the highest statistical level.

Additional Abstract Information

Student(s): Christopher A Castillo

Department: Physics and Astronomy

Faculty Advisor: Dr. Anca Constantin

Type: Poster

Year: 2015