Ultra-deep Large Binocular Camera U-band Imaging of the GOODS-North Field: Depth vs. Resolution
Abstract
We present a study of the trade-off between depth and resolution using a large number of U-band images in the GOODS-North field obtained with the Large Binocular Camera (LBC) on the Large Binocular Telescope (LBT). Having acquired over 30 hours of total exposure time (315 images, each 5-6 min), we generated multiple image mosaics, starting with the subset of images with the best (FWHM < 0."8) atmospheric seeing (~10% of the total data set). For subsequent mosaics, we added in data with larger seeing values until the final, deepest mosaic included all images with FWHM < 1."8 (~94% of the total data set). For each mosaic, we created object catalogs to compare the optimal-resolution, yet shallower image to the low-resolution but deeper image and found the number counts for both images are ~90% complete to AB = 26 mag. In the optimal-resolution image, object counts start to drop-off dramatically, fainter than AB ~ 27 mag, while in the deepest image the drop is more gradual because of the better surface-brightness sensitivity ( SB ~ 32 mag arcsec-2). We conclude that for studies of brighter galaxies and features within them, the optimal-resolution image should be used. However, to fully explore and understand the faintest objects, the deeper imaging with lower resolution are also required. We also discuss how high-resolution F336W HST data complements our LBT mosaics.For 220 brighter galaxies with U < 24 mag, we find only marginal differences (< 0.07 mag in total integrated flux) between the optimal-resolution and low-resolution light-profiles to SB ~ 32 mag arcsec-2. This helps constrain how much flux can be missed in galaxy outskirts, which is important for studies of Extragalactic Background Light.In the future, we will expand our analysis of the GOODS-N field to ~26 hours of LBT/LBC R-band surface photometry to similar depths.
- Publication:
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American Astronomical Society Meeting Abstracts #229
- Pub Date:
- January 2017
- Bibcode:
- 2017AAS...22943806A