Abstract by Jackson Steele
Physics and Astronomy
J. Ward Moody
Measuring distances to emisson-line galaxies photometrically
Finding distances is among the greatest challenges modern astronomy faces today. We can measure galactic distance using spectroscopy with impressive accuracy, but spectroscopy requires large telescopes and expensive equipment that is not widely available. Distances can also be measured photometrically, but with a resolution too low for mapping out the distribution of galaxies, particularly in areas with few galaxies. Given that the proportion of emission-line galaxies increases near these low-density areas, we have developed a filter system to photometrically measure distance for emission-line galaxies with a cz between 3000 km/s and 9000 km/s to an accuracy of 572 km/s. Our filter system is composed of three filters—one continuum-measuring filter and two linearly-sloping filters covering the same wavelength range but with opposite slopes. These work together to isolate the wavelength of the H-alpha emission line, from which we can measure the distance to galaxies.