Caryl Gronwall

Senior Scientist
Astronomy & Astrophysics

417B Davey Lab
University Park, PA 16802

Phone: +1 814-865-2918
Fax: +1 814-863-3399


Personal webpage
Caryl Gronwall

I am an observational astronomer who specializes in studying the formation and evolution in galaxies. My research has used multiple ground and space-based observatories. In particular, my research concentrates on understanding the star formation history of the universe studying both nearby and distant galaxies using observations at a wide range of wavelengths. I also study the nature of dark energy in the universe via the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX).

I am a leader of the MUlti-wavelength Survey by Yale and Chile (MUSYC) collaboration aimed at studying the properties of Lyman-alpha emitting galaxies between 2.1 < z < 3.1. These Lyman-alpha emitters are often called "caught in the act of formation" and are likely the progenitors of today's Milky Way-type galaxies. We have measured the luminosity function, equivalent width distribution, size distribution, clustering properties, mass-specific star-formation rates, and star-formation histories of these galaxies. Starting this year, we will begin using the South African Large Telescope; SALT) to obtain follow-up spectroscopy of these galaxies and determine their kinematic properties. Understanding the properties of these galaxies not only provides unique insights into formation of our own Galaxy, but also provide crucial input into the experimental design of the HETDEX project.

I am a founding member of the Hobby Eberly Telescope Dark Energy Experiment (HETDEX), a blind spectroscopic survey aimed at measuring the effects of Dark Energy at a time when the universe was only 15% of its current age. HETDEX will begin taking data in fall 2012. This project, which is led from the University of Texas, will obtain spectra of nearly a million Lyman-alpha emission line galaxies, located at redshifts between two and four, and use this information to measure the expansion history and curvature of the universe to better than 1%. HETDEX will also obtain spectra for over a million (0II) emitting galaxies, a quarter of a million Milky Way stars, 2000 galaxy clusters, 25,000 active galactic nuclei, and 0.4 million other objects. I will lead the study of the properties of star-forming galaxies from the massive HETDEX dataset including both the high- redshift LAEs as well as the lower redshift (0 II) galaxies. I also participate in the complimentary HETDEX imaging survey, a large parallel project which will greatly enhance our ability to exploit the data products of the experiment.

In addition, I am a member of the Swift science team. Swift's main scientific mission is to discover and characterize gamma-ray bursts including some of the most distant objects ever detected in the universe such as GRB 090423 at z=8.2 and GRB 050904 at z=6.3. My Swift research mainly concentrates on using Swift's UV/Optical Telescope (UVOT) to study star-formation in both nearby and distant galaxies. This includes studying the properties nearby star-forming galaxies in the ultraviolet using Swift. These images provide details on the star-formation histories and dust properties of these galaxies. I also conceived and led the observations of the Swift Deep Field, an extremely deep (500 ks) image of the Chandra Deep Field-South taken in the ultraviolet using UVOT. My collaborators and I use this image to study the evolution of star- forming galaxies out to z~1.

I am also a member of the JANUS (Joint Astrophysics Nascent Universe Satellite) project which is a proposed NASA Explorer mission to probe the "cosmic dawn" by observing the most distant gamma-ray bursts and quasars.