SAGE (v3) IRAC Matched Multi-Epoch Catalog & Archive Definition

SAGE Overview

The Spitzer Space Telescope Survey of the Large Magellanic Cloud Legacy Project Surveying the Agents of a Galaxy's Evolution (SAGE) traces the life cycle of observable matter that drives the evolution of a galaxy's appearance. SAGE has revealed over 6 million sources including ~150,000 evolved stars, ~50,000 young stellar objects and the diffuse interstellar medium with column densities > 1.2×1021 cm -2. The data will provide fundamental insights into the physical processes of the interstellar medium, the formation of new stars and the injection of mass by evolved stars and their relationships on the galaxy-wide scale of the Large Magellanic Cloud.

The SAGE project page can be found here. The survey is described in Meixner et al. (2006). (AJ, 132, 2268). Also provided with the data release is the SAGE data delivery documentation [PDF].

SAGE (v3) IRAC Catalog & Archive Criteria

In comparison to the catalog, the archive has more source fluxes (fewer nulled wavelengths) and some more sources but these additions have more uncertainty associated with them. For the catalog, the S/N must be greater than [6, 6, 6, 10] for IRAC bands [3.6um], [4.5um], [5.8um] and [8.0um] for the flux to appear in the corresponding wavelength column. Whereas for the archive, the S/N must be greater than [5, 5, 5, 5] for IRAC bands [3.6um], [4.5um], [5.8um] and [8.0um]. For the catalog, sources with neighbors within a 2" radius are excluded (culled). For the archive, sources within a 0.5" are excluded. The difference in criteria for the catalog and archive creation is more complex and described in Section 5.2 of the SAGE Data Delivery Document [PDF].

The Matched Multi-Epoch Catalog and Archive contains matches between the Epoch 1 and Epoch 2 Catalog and Archive, respectively. Both epochs are listed separately in the Epoch 1 and Epoch 2 Catalog and Archive. For a detailed discussion of the matching criteria, see Section 6.3 of the Data Delivery Document.

SAGE (v3) IRAC Matched Multi-Epoch Catalog & Archive Column Descriptions

Gator serves the SAGE IRAC Matched Multi-Epoch Catalog (21 columns [16 delivered + 5 IRSA-created], 647,865 data rows), and the SAGE IRAC Multi-Epoch Archive (21 columns [16 delivered + 5 IRSA-created], 668,718 data rows).

Name Intype Units Description
E1designation char SAGE IRAC or MIPS24 Epoch 1 source designation name
E1globalSourceID int Unique identification number of the epoch 1 source
ra double deg Right ascension (J2000) of the epoch 1 source
dec double deg Declination (J2000) of the epoch 1 source
E2designation char SAGE IRAC or MIPS24 Epoch 2 source designation name
E2globalSourceID int Unique identification number of the epoch 2 source
E2ra double deg Right ascension (J2000) of the epoch 2 source
E2dec double deg Declination (J2000) of the epoch 2 source
avgf36 double mJy average of the epoch 1 and epoch 2 - 3.6um IRAC (Band 1) flux
V36 double mJy Variability index for the 3.6um IRAC (Band 1)
avgf45 double mJy average of the epoch 1 and epoch 2 - 4.5um IRAC (Band 2) flux
V45 double mJy Variability index for the 4.5um IRAC (Band 2)
avgf58 double mJy average of the epoch 1 and epoch 2 - 5.8um IRAC (Band 3) flux
V58 double mJy Variability index for the 5.8um IRAC (Band 3)
avgf80 double mJy average of the epoch 1 and epoch 2 - 8.0um IRAC (Band 4) flux
V80 double mJy Variability index for the 8.0um IRAC (Band 4)