The 2MASS raw data contain several different types of artifacts, some from the sky and environment and some from the camera electronics. The current known artifacts that may affect the sampler data are:
Meteor and airplane streaks produce a linear streak or streaks across a single raw camera frame. The streak survives to the Atlas Image with its intensity reduced by a factor of 2-6, depending on the number of raw frames present at a given position of the Atlas Image. Meteors usually produce a single streak, although bright meteors can produce a series of persistence streaks in a given Atlas Image. Airplanes often produce 3 parallel streaks, due presumably to the wing lights. None of the examples linked here are from the Sampler night.
We do not reobserve scans affected by streaks, nor do we have a reliable working streak detector at the moment. However, the streaks are usually quite obvious in the Atlas Images, which should be consulted if the user has any doubt about the reality of a reported source. The point and extended sources associated with the known meteor streaks on the sampler night have been excised from the released catalogs.
Streaks from other sources may also exist. For example, we have seen an H-only streak that persists in ~6 frames in the southern data and a "weird" set of five non-parallel streaks which do have the same apparent convergent point!
For more information, see "Meteor" Streaks Found From Visual Inspection of Coadds and False Sources.
Insects produce a bizarre gallery of features that have given rise to terms, such as "walking donut", "smudges", "ladybugs", etc. We attempt to identify all such features as part of the quality analysis, and reject scans where such features have been detected. However, it is possible that some of these features, especially ones that might be a lower levels, might have escaped detection. Most examples from rejected scans have not been saved, but we have available a "moth" emitting at Ks and absorbing at J and H.
Electronic noise pickup causes several different kinds of residual emission in the Atlas Images, and some types affect extended source photometry (see section below). For a summary of what is currently known and pictures of affected Atlas Images, see Data Artifacts: Electronic Pickup Noise.
