My main research interests are (click for more details):
  • Emission line galaxies
Emission lines are probes for various galaxy properties, including star formation rates, metallicities, and dust properties. In many galaxies they are also the easiest way to determine the redshift and are often the only spectral feature that is observed.

Deep near-IR observations have uncovered an abundant population of faint, emission line-dominated galaxies. In Maseda et al. 2013 and 2014, I show that with very bright [O III] and Hα emission lines compared to the underlying continuum flux, these "Extreme Emission Line Galaxies" are plausibly starbursting dwarf galaxies. These dwarfs may be in a common evolutionary phase for low mass galaxies, which would be a crucial link in combining studies of local galaxies and those at higher redshifts.

In Maseda et al. 2018a, I develop a new method to systematically find these galaxies in grism spectroscopic data. This allows me to measure the evolution in the number density of these low-mass galaxies across cosmic time, finding that they are significantly more common at higher redshifts. This has strong implications for future deep spectroscopic surveys with JWST/NIRSpec, WFIRST, Euclid, and the ELTs (Maseda et al. 2019). Using MUSE, I study the restframe-ultraviolet spectra of high-redshift galaxies. Features in this part of the spectrum, such as the C III] and Lyman-alpha emission lines, provide a lot of information about the physical state of these young galaxies. This type of study is extremly powerful when combined with information from the restframe-optical region, which can be obtained with Hubble's WFC3 camera. A key strength to this approach is the un-targeted nature of both instruments, allowing us to get a clear view of the full population of galaxies.

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