Rebecca McClain:
Ionization in the Circumgalactic Medium of Mariposa

Becca McClain (F&M ‘22) is measuring a the sources of ionization in the extended gas distribution of a fascinating galaxy we have named “Mariposa” in honor of a former F&M student. Using Keck/MOSFIRE spectroscopy, Becca measured the [N II]/Hα and [O III]/Hβ ratios of Mariposa’s eastern “wing” to determine that the ionization was consistent with the large-scale affects of an AGN (i.e., the blue cross in the above diagram lies above the red line, which represents the maximum predicted ionization possible without a AGN). Becca is now analyzing rest-UV IFU spectra from Keck/KCWI to conduct more detailed modeling of the ionization and its spatial variation for her senior honors thesis.