SAGE (v2) Winter '08 MIPS 24 um Catalog 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. When complete, SAGE is expected to reveal 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 / PS].
SAGE MIPS 24 um Catalog Column Descriptions
Gator serves the SAGE Winter 2008 MIPS 24 um Catalog Epoch1 (34 columns [29 delivered + 5 IRSA-created], 76,238 data rows) as well as the IRAC Archive Epoch1 (88 columns [83 delivered + 5 IRSA-created], 8,785,435 data rows) and IRAC Catalog Epoch1 (88 columns [83 delivered + 5 IRSA-created], 8,522,654 data rows). SAGE MIPS 24 um catalog column descriptions can be found below. SAGE IRAC catalog column descriptions can be found here.
| Column Name | Data Type | Units | Nulls Allowed | Column Description |
| globalSourceID |
int | n | Unique identification number of each source in the catalog | |
| sourceCatalog |
char | n | Character string identifier for source catalog | |
| epoch |
char | n | Character string identifier for the epoch of the observation of the source, i.e. "epoch 1", "epoch 2", "epoch 1+2",... | |
| designation |
char | n | SAGE source designation name.
Designation is SST = Spitzer Space Telescope M1 = MIPS 24um SAGE= LMC Survey project 1 = epoch 1+2 C = Catalog J = 2000.0 epoch HHMMSS.SS Right ascension (hr, min, sec) of source sDDMMSS.S Declination (deg, min, sec) of source | |
| ra |
double | deg | n | Right ascension (J2000) |
| dec |
double | deg | n | Declination (J2000) |
| dra |
double | arc seconds | n | Error in right ascension |
| ddec |
double | arc seconds | n | Error in declination |
| conf24 |
int | y | Confusion Flag for 24um, currently unused | |
| flux24 |
double | mJy | y | 24um flux |
| dflux24 |
double | mJy | y | 24um 1 sigma error |
| mag24 |
double | mag | y | 24um magnitude |
| dmag24 |
double | mag | y | 24um 1 sigma error |
| sky24 |
real | MJy/sr | y | Local sky background for 24um, computed by measuring the surface brightness at the source location in the source subtracted image. This background includes contributions from the zodiacal light, Milky Way foreground emission, and extended emission in the LMC. |
| SN24 |
real | y | 24um Signal/Noise | |
| flag24 |
int | y | The flag currently refers to how many times a source was observed by different AORs in a single epoch. If it was observed more than once, the reported flux is the average of the multiple observations. | |
| correlation24 |
double | y | The value of the correlation indicates how close this source PSF is to a point source. The mathematical definition of the correlation is given in eq. 2 of Diolaiti, E. et al. (2000, A&AS, 147, 335). The value starts at 1 for an exact noiseless match to a point source and reduces as the source becomes more extended and/or the noise increases. The catalog only contains sources which have correlation values above 0.8 except for the special case of close double sources. In this case, the correlation value is set to -1 as it is not possible to compute the correlation value uniquely for each of the two sources. Thus, the correlation value in the catalog can have a value of -1 (for double sources) or between 0.8 and 1 (single sources). | |
| mmmNsky24 |
double | n | Number of points used to determine the sky values for mmmSkymode24, mmmSigma24 and mmmSkew24 | |
| mmmSigma24 |
double | n | Scalar giving standard deviation of the peak in the sky histogram | |
| mmmSkew24 |
double | n | Scalar giving skewness of the peak in the sky histogram | |
| mmmSkymode24 |
double | n | Scalar giving estimated mode of the sky values | |
| AORNumber24 |
int | n | Request key for the 1st AOR within which the source appears | |
| averageCoverage24 |
double | n | The average coverage (# of independent observations per pixel) | |
| versionNo |
smallfloat | n | Version number assigned by MIPS/IRAC pipeline team | |
| versionDate |
char | n | Date catalog was produced in the following format, "mon dd yyyy", "Dec 5 2007" | |
| cx |
double | n | x of unit vector on the unit sphere for ra,dec of this source | |
| cy |
double | n | y of unit vector on the unit sphere for ra,dec of this source | |
| cz |
double | n | z of unit vector on the unit sphere for ra,dec of this source | |
| htmID | long | n | The Hierchical Triangular Mesh partition, computed at index level 20, in which this source lies. |