Data Anomalies and Artifacts

Data anomalies and image artifacts come in a variety of flavors, including those from the local environment (Observatory and atmosphere), space (meteor streaks, bright stars), from the equipment (array detectors, telescope tracking and focus), and from the software (algorithm and pipeline bugs). Extended sources are vulnerable to most of these problems, but in particular those in which the image backgrounds are corrupted. For example, bright stars (K < 7th mag) induce several image artifacts, including confusion halos, large-angular extent diffractions spikes, horizontal striping, persistence ghosting, reflection glinting, and large-scale background corruption for the brightest stars (K < 3rd mag). Examples of data artifacts from bright stars were discussed in Section 5.

An extensive amount of analysis work has been carried out to understand the types of data anomalies and image artifacts inherent to the 2MASS data archive. The links below point to summaries and specific tasks to this end.