The Utility of Lyman-Alpha Emission Lines as Probes of High Redshift Outflows
Date Submitted
2017-04-13 15:53:57
HighRed
Henry Childs
University of Warwick
Poster
Dr. Elizabeth Stanway (Warwick)
Observational limitations mean the best window for finding high redshift outflow markers is in the rest-UV. It has been proposed that rest-UV morphology correlates with Lyman alpha spectral properties and so may provide a proxy for the detection of galaxy outflows. This would have the advantage of making large samples of archival data accessible for studies of the interactions between the young massive stellar populations in early galaxies and their nearby circumgalactic and intergalactic media. However observational uncertainties may compromise this analysis in many cases. The initial work was performed with HST and Keck data - amongst the highest quality and signal to noise of all high redshift datasets. In this study we explore whether the correlation between morphological asymmetry and Lyman-alpha skewness (both hypothesised outflow indicators) holds at lower instrumental resolution and detection signal-to-noise and thus whether the methodology can be extended throughout the archive. We model these effects, and others such as skyline removal, on the parameter recovery of skewed Gaussian emission lines. Unsurprisingly we find a strong bias in results at lower resolutions and high skew values, as-well as substantial uncertainties resulting from the masking of skylines. We present analysis of a range of existing data sets (including sources from FORS2 and DEIMOS) and attempt to reconstruct the recovered initial emission line parameters. We also investigate the possibilities of recovering outflow indicators from line emission with future instruments like JWST and the E-ELT.