Photo Credit:
ESO Photo Ambassador Babak Tafreshi
My Research Interests:
Highly Efficient Star Formation

Most recently I have become enamored with the topic of star formation in its varied forms. Working with Professor Turner, I study star forming clouds in the millimeter and submillimeter looking to understand how and why some clouds have remarkably high efficiency. Star formation efficiency can be defined as the percentage of a molecular cloud that consists of newly formed stars. Star forming clouds in the Milky Way form stars with an efficiency of less than ~5%, whereas some observed clouds in other galaxies have efficiencies of higher than 50%, though we do not understand why or how. The more interesting piece is that we know our galaxy used to have regions with efficiencies higher than ~50% around 10 billion years ago, as there are globular clusters in our galaxy, and globular cluster formation requires high star formation efficiencies. Yet to see long-lived star formation, like in our galaxy which continues to form stars today, requires low efficiency, or the galaxy will run out of gas with which to form stars. Thus, switching from high efficiency to low efficiency must be an evolutionary trend in the Milky Way which we do not yet understand. I hope to understand that trend by finding more galaxies either in the process of forming stars efficiently, or ending the sequence of efficient formation and mapping out their evolution.


One of the main products of stellar activity is dust. Regions with lots of young stars will be polluted with thousands of stellar masses of dust. However, by the time most star forming regions are observed, some of the young stars have gone supernova and blown holes in their surrounding medium, releasing gas and dust into the galaxy. Thus, it is frequently difficult to get an accurate measure of the amount of dust present in a cluster, especially in comparison to the gas. Accurately estimating dust output, and its effect on the cluster it was born into is an important key to measuring star formation. Luckily, with ALMA and the SMA we can attempt to directly observe the dust and get estimates of dust mass, and a gas-to-dust ratio for the cloud.


Another important aspect to star formation is feedback. Energetic young stars give out ionizing photons and soot, changing the medium around them. Not only do the stars affect their natal cloud, eventually destroying it as they evolve, but the stars also affect their galactic surroundings. As stars evolve and explode, they punch holes in the galaxy, allowing space for ionizing photons to travel and for the reach of feedback from the star forming regions to expand. One of the goals of our research is trying to see to what extent recently formed stars have on their surroundings, and at what point they begin to truly change the cloud they formed in.