University of Massachusetts Department of Astronomy LGRT-B 638 710 North Pleasant Street Amherst, MA 01003-9305


Ph.D. Cornell, 1985

M.S., Cornell, 1982

B.A. Harvard, 1979

Research Interests

My research focuses on understanding properties of galaxy populations and particularly the relationship between galaxies' gaseous and stellar content. These comparisons are based on observations carried out at radio wavelengths to study the gas, and at optical and infrared wavelengths to study the stars. I've carried out observations at 21-cm at the Arecibo, Green Bank, the VLA, and Nançay radio telescopes. My optical studies have used Kitt Peak and Sierra San Pedro de Mártir Observatories. I was part of the original science team that designed the 2-Micron All Sky Survey (2MASS) and created the extended-source catalog, which I used as the basis for several follow-up studies at radio wavelengths. More recently I've used the large database of visual-wavelength observations in the Sloan Digital Sky Survey to complement the 21-cm observations. 

My interest in this area of research was piqued when as a graduate student I discovered a large intergalactic hydrogen cloud that showed no traces of stars despite having billions of solar masses of gas. This cloud is twice the size on the sky as the full moon, yet virtually invisible at optical wavelengths, and I discovered it accidentally during calibration observations at Arecibo. This raised questions in my mind about the kinds of biases we have in our studies of galaxies based on our focus on visible light. 

Teaching Statement

Teaching is fun! I'm delighted by the profound questions students can ask, and I try to foster an environment where everyone feels comfortable asking questions. I like to say to students "You are your 'why?'" because the questions they ask guide their own thinking and approach to academics and life. I like doing projects and activities in class and working out ways to interact with everyone, whether there are 3 or 300 students. "Flipped" classroom approaches intrigue me, but I also believe in a good, well-organized lecture where I can lead students through a lengthy path of reasoning. I try to mix up my approach a little bit every time I teach a course so the material is fresh to me in a way that will help me remember the questions I had when I first learned the material.