SMC-Last Extracted Photometry Catalog Definitions

Overview

We present point-source photometry from the Spitzer Space Telescope's final survey of the Small Magellanic Cloud (SMC). We mapped nearly 30 square degrees in two epochs in 2017, with the second extending to early 2018 at 3.6 and 4.5 um using the Infrared Array Camera. This survey duplicates the footprint from the SAGE-SMC program in 2008. Together, these surveys cover a nearly 10 yr temporal baseline in the SMC. We performed aperture photometry on the mosaicked maps produced from the new data. We did not use any prior catalogs as inputs for the extractor in order to be sensitive to any moving objects (e.g., foreground brown dwarfs) and other transient phenomena (e.g., cataclysmic variables or FU Ori-type eruptions). We produced a point-source catalog with high-confidence sources for each epoch as well as a combined-epoch catalog. For each epoch and the combined-epoch data, we also produced a more complete archive with lower-confidence sources.

If you use the SMC-Last Catalogs, please cite Kuchar et al. (2024).

Name Intype Units Description
designation char none Designation
ra float deg Right Ascension (J2000)
dec float deg Declination (J2000)
posunc float arcsec Radial positional uncertainty
flux_36 float mJy 3.6 micron flux
uncflux_36 float mJy 3.6 micron flux uncertainty
aper_36 int arcsec 3.6 micron extraction aperture diameter
fwhm_36 float arcsec 3.6 micron FWHM
elong_36 float none 3.6 micron elongation
meanmjd_36 double days Mean MJD of 3.6 micron observations
minmjd_36 double days Minimum MJD of 3.6 micron observations
maxmjd_36 double days Maximum MJD of 3.6 micron observations
satfill_36 int none Saturation filling flag; 1 indicates use of 0.6sec data within the aperture
aper_frac_36 float none Fraction of pixels within the 3.6 micron aperture with valid data
sky_36 float MJy/sr Average sky brightness in the 3.6 micron background annulus
rms_36 float MJy/sr RMS in the 3.6 micron background annulus
cvg_36 int none Number of 3.6 micron BCDs contributing to the source
plate_36 char none 3.6 micron plate
dpos float arcsec Radial separation between 3.6um and 4.5um extracted positions
nearest_src float arcsec Distance to nearest neighbor within 20 arcsec
nproximity int arcsec Number of neighbors within 5 arcsec
brgt_nbr int none Bright neighbor flag: source >10 mJy within 1.2 arcsec
flux_45 float none 4.5 micron flux
uncflux_45 float mJy 4.5 micron flux uncertainty
aper_45 int mJy 4.5 micron extraction aperture diameter
fwhm_45 float arcsec 4.5 micron FWHM
elong_45 float arcsec 4.5 micron elongation
meanmjd_45 double none Mean MJD of 4.5 micron observations
minmjd_45 double days Minimum MJD of 4.5 micron observations
maxmjd_45 double days Maximum MJD of 4.5 micron observations
satfill_45 int days Saturation filling flag; 1 indicates use of 0.6sec data within the aperture
aper_frac_45 float none Fraction of pixels within the 4.5 micron aperture with valid data
sky_45 float none Average sky brightness in the 4.5 micron background annulus
rms_45 float MJy/sr RMS in the 4.5 micron background annulus
cvg_45 int MJy/sr Number of 4.5 micron BCDs contributing to the source
plate_45 char none 4.5 micron plate