The SAMI Galaxy Survey: cubism and covariance, putting round pegs into square holes

• Main Authors: Sharp, R., Allen, J. T., Fogarty, L. M.R., Croom, S. M., Cortese, L., Green, A. W., Nielsen, J., Richards, S. N., Scott, N., Taylor, E. N., Barnes, L. A., Bauer, A. E., Birchall, M., Bland-Hawthorn, J., Bloom, J. V., Brough, S., Bryant, J. J., Cecil, G. N., Colless, M., Couch, W. J., Drinkwater, M. J., Driver, S., Foster, C., Goodwin, M., Gunawardhana, M. L.P., Ho, I. T., Hampton, E. J., Hopkins, A. M., Jones, H., Konstantopoulos, I. S., Lawrence, J. S., Leslie, S. K., Lewis, G. F., Liske, J., López-Sánchez, R., Lorente, N. P.F., McElroy, R., Medling, A. M., Mahajan, S., Mould, J., Parker, Q., Pracy, M. B., Obreschkow, D., Owers, M. S., Schaefer, A. L., Sweet, S. M., Thomas, A. D., Tonini, C., Walcher, C. J.
• Other Authors: University of North Carolina at Chapel Hill
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2015
• Subjects: Techniques: imaging spectroscopy; QB; QC Physics; QB Astronomy; Journal article; Methods: data analysis; QC; Instrumentation: spectrographs; sami
• Online Access: https://doi.org/10.17615/fzcj-dr19; https://cdr.lib.unc.edu/downloads/qn59qd368?file=thumbnail; https://cdr.lib.unc.edu/downloads/qn59qd368

We present a methodology for the regularization and combination of sparse sampled and irregularly gridded observations from fibre-optic multiobject integral field spectroscopy. The approach minimizes interpolation and retains image resolution on combining subpixel dithered data. We discuss the methodology in the context of the Sydney-AAO multiobject integral field spectrograph (SAMI) Galaxy Survey underway at the Anglo-Australian Telescope. The SAMI instrument uses 13 fibre bundles to perform high-multiplex integral field spectroscopy across a 1° diameter field of view. The SAMI Galaxy Survey is targeting ~3000 galaxies drawn from the full range of galaxy environments. We demonstrate the subcritical sampling of the seeing and incomplete fill factor for the integral field bundles results in only a 10 per cent degradation in the final image resolution recovered. We also implement a new methodology for tracking covariance between elements of the resulting data cubes which retains 90 per cent of the covariance information while incurring only a modest increase in the survey data volume.