SAGE-SMC: Infrared Photometry Catalog of the Small Magellanic Cloud

SAGE-SMC is a legacy program from the Spitzer Space Telescope Cycle 4, led by Karl Gordon at STScI. The catalog provides infrared photometry of sources in the Small Magellanic Cloud, processed with strict detection criteria requiring a signal-to-noise ratio greater than 5 or 7 across IRAC bands. The data includes observations from two epochs separated by 3 months to mitigate instrument artifacts and constrain source variability.

Use Cases

• Identify and classify evolved stars and young stellar objects based on multi-epoch infrared photometry.
• Study source variability in the Small Magellanic Cloud using the two observation epochs separated by 3 months.
• Analyze the stellar population and structure of a tidally disrupted, low-metallicity dwarf galaxy.
• Perform photometric cross-matching and validation with the 2MASS K_s band, which is counted as a detection.

Strengths

• Implements strict detection criteria: sources must be detected in at least 60% of observations at a wavelength and 32% in an adjacent band.
• Requires high signal-to-noise ratios: greater than 5 for IRAC bands 3.6um, 4.5um, and 5.8um, and greater than 7 for the 8.0um band.
• Uses multi-epoch observations to remove striping artifacts and provide constraints on source variability.

Limitations

• Row count is unknown, which may limit suitability assessment.
• Column-level documentation is absent; field semantics must be inferred after download.
• Data may reflect observational bias inherent to the Spitzer Space Telescope's coverage and sensitivity limits.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Observations from the Spitzer Space Telescope's IRAC instrument, reduced using specialized software as part of the SAGE-SMC legacy program.

Time Range

Observations from two epochs (Epochs 1 and 2) separated by 3 months, plus data from an earlier S3MC pathfinder survey (Epoch 0).

Freshness

Last updated 2026-03-13 18:19:32.541016; freshness should be verified.

Geography

The Small Magellanic Cloud, a dwarf galaxy satellite of the Milky Way.