부산대학교 도서관

Upcoming imaging surveys, such as LSST, will provide an unprecedented view ofthe Universe, but with limited resolution along the line-of-sight. Common waysto increase resolution in the third dimension, and reduce misclassifications,include observing a wider wavelength range and/or combining the broad-bandimaging with higher spectral resolution data. The challenge with theseapproaches is matching the depth of these ancillary data with the originalimaging survey. However, while a full 3D map is required for some science,there are many situations where only the statistical distribution of objects(dN/dz) in the line-of-sight direction is needed. In such situations, there isno need to measure the fluxes of individual objects in all of the surveys.Rather a stacking procedure can be used to perform an `ensemble photo-z'. Weshow how a shallow, higher spectral resolution survey can be used to measuredN/dz for stacks of galaxies which coincide in a deeper, lower resolutionsurvey. The galaxies in the deeper survey do not even need to appearindividually in the shallow survey. We give a toy model example to illustratetradeoffs and considerations for applying this method. This approach will allowdeep imaging surveys to leverage the high resolution of spectroscopic andnarrow/medium band surveys underway, even when the latter do not have the samereach to high redshift.