The Hubble Source Catalog (HSC) is designed to optimize science from the Hubble Space Telescope by combining the tens of thousands of visit-based source lists in the Hubble Legacy Archive (HLA) into a single master catalog.
Version 3 was released on 2018 July 5 and includes many improvements in the photometry and astrometry along with a significant increase in the number of objects and measurements.
Highlights from Version 3 include:
The HSC v3 contains members of the WFPC2, ACS/WFC, WFC3/UVIS and WFC3/IR Source Extractor source lists from HLA version DR10 (data release 10). The cross-matching process involves adjusting the relative astrometry of overlapping images so as to minimize positional offsets between closely aligned sources in different images. After correction, the astrometric residuals of cross-matched sources are significantly reduced, with median errors less than 8 mas. The absolute astrometry is calibrated using Gaia DR1, Pan-STARRS, SDSS, and 2MASS as the astrometric backbone for initial corrections. In addition, the catalog includes source nondetections. The cross-matching algorithms and the properties of the initial (Beta 0.1) catalog are described in Budavari & Lubow (2012), and the Version 1 catalog is described in Whitmore et al. (2016).
There are currently four ways to access the HSC as described below. We are working towards having these interfaces consolidated into one primary interface, the MAST Discovery Portal.
1. Detailed Use Cases and Videos are available.
2. Sky coverage can be very non-uniform (unlike surveys such as SDSS) due to the highly variable HST observing patterns.
3. Current WFPC2, ACS/WFC and WFC3 source lists are of variable quality. In particular, the WFPC2 source lists are of poorer quality than the ACS and WFC3 source lists.
4. The default is to show all HSC objects. This may include a large number of artifacts. You can request NumImages > 1 (or more) to filter out many artifacts.
5. The default is to use mag_aper2 Source Extractor values for magnitudes (in the ABMAG system) . You can request mag_auto if desired.
More detailed information can be found on the Frequently Asked Questions page. Several Use Cases are available to give you step by step instructions. There are also videos available.
We are interested in your feedback. If you have questions, or items to bring to our attention, please send them to: archive help.
HSC Data Use Policy: The HSC is based on data from the Hubble Legacy Archive (HLA). Refereed publications making use of the HSC should therefore include this footnote in the acknowledgements:
Based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESAC/ESA) and the Canadian Astronomy Data Centre (CADC/NRC/CSA).
Authors are also asked to acknowledge the "Hubble Source Catalog" in the text of the paper, and consider a reference to the Whitmore et al.(2016) paper describing the HSC.