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Stacking of Interferometric Data: New Tools for Stacking of ALMA Data

Kirsten Kraiberg Knudsen (Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium) ; Lukas Lindroos (Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium) ; Wouter Vlemmings (Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium) ; John Conway (Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium) ; Ivan Marti-Vidal (Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium)
4th ALMA Science Conference on Revolution in Astronomy with ALMA: The Third Year, Tokyo, Japan, 8-11 December Vol. 499 (2015), p. 81-82.
[Konferensbidrag, refereegranskat]

Radio and mm observations play an important role in determining the star formation properties of high-redshift galaxies. With the unprecedented sensitivity, ALMA now enable studies of faint, distant star-forming galaxies. However, most galaxies with low star formation rates at high redshift are too faint to be detected individually at these wavelengths. A way to study such galaxies is to use stacking. By averaging the emission of a large number of galaxies detected in optical or near-infrared surveys, we can achieve statistical detection. We investigate methods for stacking data from interferometric surveys. Interferometry poses unique challenges in stacking due to the nature of this data. We have compared stacking of uv-data with stacking of imaged data, the latter being the commonly used approach. Using simulated data, we find that uv-stacking may provide up to 50% less noise and that image based stacking systematically loses around 10% of the flux. More importantly, we find that the uv-stacking yield more robust results, especially in the case of (marginally) resolved sources and mosaicked data.



Denna post skapades 2016-03-02.
CPL Pubid: 232653