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Detecting Ly-alpha Emission from the Circumgalactic Medium of a Submillimeter Galaxy and Two Background Quasars

Kevin Hall; University of Iowa

Some of the densest regions of the Early Universe can be found near massive dusty galaxies referred to as Submillimeter Galaxies (SMGs). Every year, our Milky Way galaxy forms roughly one new star the mass of our sun; SMGs can form stars at a rate anywhere from 100 to 1000 times that amount. One particular SMG has been detected with two bright Quasars (QSOs) in the background emitting light through an extended environment 100s of kiloparsecs in size surrounding the SMG at z = 2.8. We call this large environment the Circumgalactic Medium (CGM). Studying the CGM helps us understand how these young galaxies can fuel the star formation we observe as well as how they eventually evolve into the galaxies we see in the modern Universe. A previous study revealed the light from the two QSOs being absorbed by the CGM of the SMG. We now seek to observe the Hydrogen Lyman-alpha (Ly-alpha) line emission from the CGM using the Keck Cosmic Web Imager (KCWI), which is an integral field spectrograph operating within visible wavelengths. With KCWI, we are able to study the distribution of gas and kinematics present. These observations allow us to make interpretations on the possible powering mechanism driving the Ly-alpha emission.