This is a description of the current version of the Hubble Source
Catalog. You may still access HSC version 1.
Version 2.1 of the Hubble Source Catalog
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)
single master catalog.
Version 2.1 was released on January 25, 2017 and includes relatively minor additions
which should not affect most users. The additions are:
1.Tables have been made available via HSC CASJOBS providing MEDIAN
rather than MEAN values for magnitudes from the summary form (i.e.,
SumMagAper2Med for magaper2 values and SumMagAutoMed for magauto
values). 2.A table has been made available via HSC CASJOBS providing
cross-matching between Version 1 - Version 2 sources (i.e., xMatchV1).
3.Spectroscopic matches for COS, FOS, and GHRS observations have
been added for Version 2 sources that do not have Version 1 counterparts.
Version 2 includes:
Four additional years of ACS source lists (i.e., through June 9, 2015). All ACS source lists go deeper than in version 1. See current HLA holdings for details.
One additional year of WFC3 source lists (i.e., through June 9, 2015).
Cross-matching between HSC sources and spectroscopic COS, FOS, and GHRS observations.
Availability of magauto values through the MAST Discovery Portal. The maximum number of sources displayed has increased from 10,000 to 50,000.
The HSC v2 contains members of the
WFPC2, ACS/WFC, WFC3/UVIS and WFC3/IR Source Extractor source lists from HLA version DR9.1 (data release 9.1). The crossmatching 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 crossmatched sources are significantly
reduced, to typically less than 10 mas.
The relative astrometry is supported by using Pan-STARRS, SDSS, and 2MASS as the astrometric backbone for initial corrections. In addition, the catalog includes source nondetections. The crossmatching algorithms and the properties of the initial (Beta 0.1) catalog are described in Budavari & Lubow (2012).
There are currently three ways to access the HSC as described below. We are working towards having these interfaces consolidated into one primary interface, the MAST Discovery Portal.
The MAST Discovery Portal provides a one-stop web access to a wide variety of astronomical data. To access the Hubble Source Catalog v2 through this interface, select Hubble Source Catalog v2 in the Select Collection dropdown, enter your search target, click search and you are on your way. Please try Use Case Using the Discovery Portal to Query the HSC
The HSC CasJobs interface permits you to run large and complex queries, phrased in the Structured Query Language (SQL).
HSC Home Page
- The HSC Summary Search Form displays a single row entry for each object, as
defined by a set of detections that have been cross-matched and
hence are believed to be a single object. Averaged values for
magnitudes and other relevant parameters are provided.
- The HSC Detailed Search Form displays an entry for each separate
detection (or nondetection if nothing is found at that position)
using all the relevant Hubble observations for a given object (i.e., different
filters, detectors, separate visits).