Andromeda Variability Legacy Survey

University Of Hawaii, Honolulu

Investigators

Abstract

The investigators will observe the nearby Andromeda Galaxy. They will look for bright regions, which indicate stars are forming. As generations of stars are born and die, they change the chemical composition of galaxies. Gas and dust collect in spiral arms of galaxies. This dust condenses into new stars and planets. After a time, the stars explode, sending different elements into the space between stars. The investigator will observe this galaxy in detail. They will map the chemistry and energy distributions. They will use this map to measure how the birth of new stars change the shape of the galaxy. All galaxies, including our own, change through the process of star formation. The investigator will involve undergraduate and graduates students in this research, training them for future careers in science and technology. Certain types of variable stars, RR Lyrae and Cepheids, are especially useful for measuring the age of star forming regions. For these stars, the brightness changes over time in a way that depends on the age and chemical compositions. These stars can then be used as probes to measure the locations of star formation at different times and in different conditions. This project will combine the three largest sets of observations of the Andromeda Galaxy to study variable stars spanning a huge range of ages, brightness, and variability periods. The observations of these variable stars will then be used to trace the star formation history in this galaxy. The results of their study of the Andromeda galaxy will aid in understanding the star formation history of our own Milky Way Galaxy. The investigator has been a part of project making repeated observations of the Andromeda Galaxy, covering time-scales from 15 minutes to as long as 11 years. With these observations, they will discover variable stars of different types, ranging from faint RR Lyrae to bright Cepheids of all types. With ages ranging from 10 million to 10 billion years, these different classes of variables will trace different time-scales for star formation as a function of position in the galaxy. The chemical composition of the stars can also be inferred from the variability signatures, revealing the location of changes of the stellar chemistry.