Spectral Mining: Transforming Spectroscopic Galaxy Surveys into Transient Surveys

Graur Or, New York NY

Investigators

Abstract

Or Graur is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the Harvard-Smithsonian Center for Astrophysics. Graur's research seeks to transform large spectroscopic survey observations into searches for transient events (transients), such as supernova explosions and the disruption of stars by black holes, that are thought to be important in the lifecycles of stars and galaxies. Graur will study two types of transients: Type Ia Supernovae (SNe Ia), which are supernovae occurring in two stars orbiting one another; and Tidal Disruption Events (TDE), which are bright flares produced when a supermassive black hole (SMBH) at the center of a galaxy disrupts the material from a nearby star. Few SNe Ia and TDEs have been observed to date, however, and Graur's work has the potential to drastically increase the detections of SNe Ia and TDEs, allowing astronomers to study these transients in a statistical manner. Graur will also build a mentoring program in which postdoctoral scholars and graduate students will supervise high school students in advanced scientific research projects. Graur will enhance his supernova detection code to enable detection of all types of transients in large scale spectroscopic galaxy surveys, starting with the Sloan Digital Sky Survey, and will integrate the enhanced code into the upcoming Dark Energy Spectroscopic Instrument survey. The focus of his research will be to enlarge the number of SNe Ia and TDE detections to make statistical analyses of these events possible. Assembling a statistical sample of SNe Ia would allow measurement of SNe Ia rates as a function of galaxy stellar mass, thereby improving constraints on the nature of SNe Ia progenitors. Similarly, enlarging the number of TDE detections through dedicated surveys would allow a better understanding of the behavior of TDEs, and stellar parameters inferred from the TDE emission would provide a novel method to measure SMBH masses and mass distributions. For the educational component of his work, Graur will develop a research mentoring program called SRMP@Harvard, in which about 15 postdoctoral scholars and advanced graduate students will supervise about 50 high school students from the Cambridge and Boston areas in active scientific research.