SAGE-SMC IRAC Epoch 1: Infrared Source Catalog for the Small Magellanic Cloud

SAGE-SMC is a Spitzer Space Telescope legacy program surveying the Small Magellanic Cloud to understand galaxy evolution. The IRAC Epoch 1 catalog contains sources detected under strict criteria, requiring a signal-to-noise ratio greater than 5 or 7 across four infrared bands and detection in at least 60% of observations at a given wavelength. This data was produced by NASA and last updated in March 2026.

Use Cases

• Identifying and classifying evolved stars and young stellar objects based on multi-epoch infrared photometry.
• Analyzing source variability constraints provided by observations separated by a 3-month roll angle.
• Studying the effects of low metallicity on stellar processes using data from the tidally-disrupted Small Magellanic Cloud.
• Removing imaging artifacts like striping in MIPS and column/row artifacts in IRAC data through multi-epoch observation strategies.

Strengths

• Sources are filtered with strict detection criteria: S/N > [5,5,5,7] across four IRAC bands and detection in at least 60% of observations.
• Observations from two epochs separated by 3 months help constrain source variability and remove instrumental artifacts.
• The catalog excludes sources with neighbors within a 2" radius to improve source isolation.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• The description mentions the archive has more sources but with greater uncertainty, suggesting the catalog is a conservative subset.

Provenance

Source

National Aeronautics and Space Administration (NASA), Spitzer Space Telescope SAGE-SMC legacy program.

Collection Method

Infrared observations from the Spitzer Space Telescope's IRAC instrument, reduced using specialized software.

Time Range

Observations from Epoch 1, with a second epoch separated by 3 months.

Freshness

Last updated 2026-03-13 19:34:01.278085; freshness should be verified.

Geography

The Small Magellanic Cloud, a tidally-disrupted, low-metallicity dwarf galaxy.