Data Surveys
Data Surveys
Astro Data Lab hosts over 25 astronomical surveys, both images and catalogs, published across the astronomical spectrum, ranging from nearby asteroids and local universe to far, extragalactic sources, generally hosted with the approval and/or help of their authors. For some datasets, we host more than one data release.
Catalogs
Reference catalogs
From these surveys, we have considered 5 as the most important and used them as reference to crossmatch with all other surveys. They are AllWISE, Gaia DR3 (for astrometry), NSC DR2, SDSS DR17 (for spectroscopy), and unWISE DR1 (for photometry), and vice versa. All main object tables have been crossmatched against our default reference datasets within a 1.5 arcsec radius, nearest neighbor only. These tables will appear with x1p5 in their name in our table browser. Example: phat_v3.x1p5__phot_mod__gaia_dr3__gaia_source.
Added columns
For convenience to our users, we have added some of the following columns to several of the catalogs when they did not have them originally:
- elon - Ecliptic Longitude
- elat - Ecliptic Latitude
- glon - Galactic Longitude
- glat- Galactic Latitude
- htm9 - Hierarchical Triangular Mesh (HTM) index (order 9 => ~10 arcmin size)
- ring256 - HEALPIX index (Nsides 256, Ring scheme => ~14 arcmin size)
- nest4096 - HEALPIX index (Nsides 4096, Nest scheme => ~52 arcsec size
- random_id - random id assigned for random sampling, uniformly spread across all catalog rows, ranging from 0 to 100
Some names for these columns may be different in some catalogs.
In some photometric catalogs that have fluxes, we have also calculated AB magnitudes, using the formula
mag = 22.5 - 2.5log10(flux)
where the flux is the flux of the object in nanomaggies. We added them, generally following the standard nomenclature, depending on the band used. For example:
- mag_g
- mag_r
- mag_i
- mag_z
If the inverse flux variance is provided, we usually calculated signal-to-noise ratio values based on the formula
snr = flux * sqrt(flux_ivar)
where flux_ivar is the inverse flux variance. We added them with the usual nomenclature. For example:
- snr_g
- snr_r
- snr_i
- snr_z
Some catalogs have other columns calculated and added as well, like de-reddend fluxes and magnitudes, colors, etc.
