Looking for ionizing photons in our galactic backyard

Looking for ionizing photons in our galactic backyard

Title: The Optical Depth of H II regions in The Magellanic Clouds Authors: E. W. Pellegrini, M. S. Oey, P. F. Winkler, S. D. Points, R. C. Smith First Author’s Institution: Department of Astronomy, University of MichiganIt’s a common theme on astrobites that massive stars play a far more important role in galaxy evolution than one might casually assume based on their numbers alone. One of the main reasons massive stars are so important is their copious production of radiation that can ionize hydrogen gas. These energetic photons can photoionize and photodissociate atomic and molecular gas, creating hot, ionized gas that will not collapse to form new generations of stars. The hot, overpressured gas created by ionization, which astronomers refer to as an H II region, drives an ionization front capable of sweeping up and stirring gas throughout a star forming region. For particularly massive star clusters, which may contain hundreds or thousands of massive stars, the ionized region surrounding the central cluster, can extend for many hundreds of parsecs, visible to us as beautiful nebulae, like the 30 doradus star forming region in the Large Magellanic Cloud (at right). Massive clusters can also directly ionize intergalactic space, producing the diffuse ionized IGM that we know has been in place since the universe was about a billion years old. Today’s astrobite takes a close look at our nearest galactic neighbors, using a novel technique to infer the state of ionized gas and ionizing photons the Magellanic Clouds.Pellegrini and collaborators make use of imaging of the Magellanic clouds in narrowband filters centered on two emission lines of oxygen and sulfur.  These particular emission lines are produced when...
Astrobites is hiring! Click here to apply!