Published in "Outskirts of Galaxies", Astrophysics and Space Science Library, Volume 434. ISBN 978-3-319-56569-9. Springer International Publishing AG, 2017, p. 255.
https://arxiv.org/abs/1612.05405

For a PDF version of the article, click here.

Abstract: Deep imaging is a fundamental tool in the study of the outermost structures of galaxies. We review recent developments in ultra-deep imaging of galaxy disks and haloes, highlighting the technical advances as well as the challenges, and summarizing observational results in the context of modern theory and simulations. The deepest modern galaxy imaging comes from three main sources: (1) surveys such as the Sloan Digital Sky Survey's Stripe 82 project, (2) very long exposures on small telescopes, including by amateurs, and (3) long exposures on the largest professional telescopes. The technical challenges faced are common in all these approaches, and include the treatment of light scattered by atmosphere and telescope/instrument, correct flat fielding, and the subtraction of non-galaxy light in the images. We review scientific results on galaxy disks and haloes obtained with deep imaging, including the detection and characterization of stellar haloes, tidal features and stellar streams, disk truncations, and thick disks. The area of ultra-deep imaging is still very much unexplored territory, and future work in this area promises significant advances in our understanding of galaxy formation and evolution.

Table of Contents

• INTRODUCTION
• THE CHALLENGES OF ULTRA-DEEP IMAGING
• Sky Brightness
• Internal Reflections
• Flat Fielding
• Drift Scanning
• Masking and Background Subtraction
• Scattered Light
• Galactic Cirrus
• APPROACHES IN ULTRA-DEEP IMAGING
• Survey Data
• Small Telescopes
• Large Telescopes
• DISK AND STELLAR HALO PROPERTIES FROM ULTRA-DEEP IMAGING
• Thick Disks
• Truncations
• Tidal Streams
• Stellar Haloes
• PSF Effects on Imaging the Outermost Regions of Galaxies
• Satellites
• CONCLUSIONS AND FUTURE DEVELOPMENTS
• REFERENCES