My main research interests are (click for more details):
One way to diagnose these issues are to target intermediate-redshift galaxies which can have similar properties to the galaxies at the highest redshifts while also allowing us to study them in greater detail. Using deep MUSE data, I discovered a population of galaxies with C III] emission with strengths similar to the high-z observations. By comparing the distribution of their properties with those of the full galaxy population at the same redshifts, I found that they were on average younger and more intensely star-forming. By combining MUSE with HST near-IR grism data, the full restframe-UV to restframe-optical spectra revealed that the C III] emitters were all Extreme Emission Line Galaxies (and vice-versa), indicating that a burst of star formation at low metallicity is required to drive strong C III] emission (Maseda et al. 2017).
Even in areas covered by the deepest optical and near-IR imaging ever taken by Hubble (the Ultra Deep Field), I have systematically found emission lines that do not have a counterpart in the continuum imaging (Maseda et al. 2018b). These galaxies are all Lyman-alpha emitters at high-redshift, and have not been detected in the imaging because of the extreme strength of the line in an otherwise small, faint galaxy. This is the first time we have ever been able to spectroscopically study galaxies this faint in the early Universe. They challenge our current understanding of young, chemically-unevolved stellar populations; their abundant nature and intense ionizing radiation fields could hold the key to understanding cosmic Reionization. Further studies using e.g. JWST will be required in order to fully understand these systems and to further constrain stellar population models. 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.
- Emission line galaxies
- Extreme stellar populations
One way to diagnose these issues are to target intermediate-redshift galaxies which can have similar properties to the galaxies at the highest redshifts while also allowing us to study them in greater detail. Using deep MUSE data, I discovered a population of galaxies with C III] emission with strengths similar to the high-z observations. By comparing the distribution of their properties with those of the full galaxy population at the same redshifts, I found that they were on average younger and more intensely star-forming. By combining MUSE with HST near-IR grism data, the full restframe-UV to restframe-optical spectra revealed that the C III] emitters were all Extreme Emission Line Galaxies (and vice-versa), indicating that a burst of star formation at low metallicity is required to drive strong C III] emission (Maseda et al. 2017).
Even in areas covered by the deepest optical and near-IR imaging ever taken by Hubble (the Ultra Deep Field), I have systematically found emission lines that do not have a counterpart in the continuum imaging (Maseda et al. 2018b). These galaxies are all Lyman-alpha emitters at high-redshift, and have not been detected in the imaging because of the extreme strength of the line in an otherwise small, faint galaxy. This is the first time we have ever been able to spectroscopically study galaxies this faint in the early Universe. They challenge our current understanding of young, chemically-unevolved stellar populations; their abundant nature and intense ionizing radiation fields could hold the key to understanding cosmic Reionization. Further studies using e.g. JWST will be required in order to fully understand these systems and to further constrain stellar population models. 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.
