Data Release V1 of "High-quality Extragalactic Legacy-field Monitoring (HELM) with DECam" (Zhuang et al. 2024, [url])

This data release contains median source catalog and light curve of individual objects in CDF-S, COSMOS, ELAIS-S1, S-CVZ, Stripe 82, and XMM-LSS fields up to 13 September 2022.

Meidan source catalogs are stored in the "median_source_catalogs" directory while light curves of individual objects are in the "lightcurves" directory.

Column description of median source catalog.
Index: Source index
ra (degree): Right Ascension (J2000)
dec (degree): Declination (J2000)
mag_psf (mag): SExtractor PSF magnitude
mag_auto (mag): SExtractor AUTO magnitude
flags: SExtractor extraction flags
spread_model DOUBLE SExtractor model-based star-galaxy classifier
class_star DOUBLE SExtractor neural network-based star-galaxy classifier
Nexp_psf: Number of exposures with successful mag psf measurement
Nexp_auto: Number of exposures with successful mag auto measurement
Separation (arcsec): Distance between median coordinate in griz bands and u band (only in S-CVZ field)

Notes: All columns except Separation can have prefix, while all columns except Index, Nexp psf, Nexp auto, and Separation have suffix.
Prefix: "*_" indicates the associated band for the parameter, with * = one or a combination of ugriz bands (such as g in all fields or griz only for S-CVZ). If not specified (for Index, ra, and dec in all fields except S-CVZ), it represents the value for all bands combined.
Suffix: "_m" and "_err" indicate unweighted median (50%) and its corresponding error of Nexp measurements with err = 0.5 × (84th percentile − 16th percentile)/√Nexp; "_w" indicates inverse variance weighted mean (Σ(m_i/e^2_i )/Σ(1/e^2_i), where m_i and e_i represent individual measurement and its error at ith exposure, respectively); "_w_err" indicates the error associated with _w after error propagation (1/√Σ(1/e^2_i)). Specifically, "_err" = "_w_err" = error of individual measurement when Nexp=1.
Value = "-99" indicates no data or non-detection.


Column description of individual source light curve table.
ra (degree): Right Ascension (J2000)
dec (degree): Declination (J2000)
expnum: DECam exposure number
mjd (day): Modified Julian date of exposure
band: Filter (one of ugriz)
mag_psf (mag): SExtractor PSF magnitude
mag_e_psf (mag): Uncertainty of SExtractor PSF magnitude
mag_auto (mag): SExtractor AUTO magnitude
mag_e_auto (mag): Uncertainty of SExtractor AUTO magnitude
flags: SExtractor extraction flags
spread_model: SExtractor model-based star-galaxy separation
spread_model_e: Uncertainty of SExtractor model-based star-galaxy separation
class_star: SExtractor neural network-based star-galaxy separation