This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Dr Kulkarni will study the gas between galaxies and around nascent galaxies by observing its absorption lines in the spectra of more distant bright quasars. Generally, the densest gas, in the damped Lyman-alpha absorbers, is already forming stars. If these absorbers represented young galaxies, we would expect the abundance of heavy elements to rise from a low value towards roughly the solar levels at the present day, as dying stars return these elements to the gas. Instead, most such gas clouds are metal-poor. Dr Kulkarni and her collaborators have shown that 'sub-damped Lyman-alpha absorbers', of slightly lower density, do become more metal-rich over time as expected. This suggests that much star-forming activity happens in these less-dense clouds. Dr Kulkarni will conduct further studies of both damped and sub-damped Lyman-alpha absorbers. She will take spectra for a larger sample, to elucidate the physical and chemical differences between systems of low and high metal content. Using adaptive-optics techniques at the Gemini and Keck telescopes, she will obtain deep images of their star-forming regions in the near infrared. With European collaborators, she will obtain spatially resolved spectroscopy at the Very Large Telescope, to trace the motions of gas ionized by the young stars and examine gradients in gas properties. Spectroscopy of binary quasars and gravitationally lensed quasars with the Magellan telescopes will probe the spatial extent of the absorbing gas.
A graduate student will be trained by participating in the research. Dr Kulkarni will continue her outreach talks at local schools and organizations, and public observing sessions at the campus observatory. She has a strong record of mentoring students from under-represented groups in research, which she will continue.
