Archive Contents - HST
All the HST observations currently available in the EHST are being synchronised with the MAST services for HST reprocessed public data and corresponding metadata, as a result of the collaboration between the partners STScI, CADC and ESAC, within the common HST Consolidation of Pipelines project. The HST archive at ESAC/ESA contains data from the following Hubble collections and catalogues:
- The standard HST archive collection
- The Hubble Legacy Archive (HLA) collection
- Hubble Advanced Products (HAP)
- Hubble Source Catalog (HSC)
- Hubble Catalog of Variables (HCV)
Details on the collections and catalogues are given below. Please note that the Hubble Legacy Archive (HLA) collection will be added again very soon, we apologise for any inconvenience.
The HST collection in the eHST is the standard HST archive content and contains the following:
- All public (non-proprietary) HST data.
- The standard HST archive products from the active instruments (ACS, COS, STIS, WFC3).
- Data from legacy instruments (FOC, FOS, HRS, NICMOS, WFPC, WFPC2). These data have gone through a final calibration run and are not foreseen to change anymore.
Detailed information on the data produced by each instrument aboard the Hubble Space Telescope can be found in the official HST Instrument Handbooks, on the main HST Documentation page.
Release: Data Release 10.0 (8th January 2018)
The HLA is a joint project of the Space Telescope Science Institute (STScI), the Space Telescope European Coordinating Facility (ST-ECF), and the Canadian Astronomy Data Centre (CADC). The HLA collection in the eHST contains enhanced image products for WFPC2 (produced by the CADC), ACS, NICMOS and WFC3 (produced by the STScI). Spectroscopy will be added very soon.
Hubble Advanced Products (HAP) have begun to be produced by MAST, STScI in the HST data pipeline, from mid December 2020 onwards, and are made available in the eHST archive as they are produced in the pipeline. These first HAPs are ACS and WFC3 Hubble Legacy Archive (HLA)-style mosaics comprising the data from a single HST visit which are aligned to a common astrometric reference frame. It is anticipated that it will take roughly one to two months before all the archival data have been processed to create mosaic products.
Three levels of products are available as part of the first release:
- Exposure level products contain data from a single HST exposure.
- Filter level products are produced from all exposures in a visit with a common filter.
- Total level products combine all exposures from a visit and are intended as a detection image for producing catalogs.
See here for more HAP information.
- Release: 3.1 (27th June 2019)
- Source: Space Telescope Science Institute (STScI)
Reference: Whitmore et al. 2016, ApJ, 151, 134
The Hubble Source Catalog is a combination of all the visit-based source lists in the Hubble Legacy Archive (HLA) into a single catalogue and 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.
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).
Version 3 includes (see here for more details):
- There are approximately 25% more ACS source lists and almost twice as many WFC3 source lists compared with HSC v2.
- The source list photometric quality is significantly improved.
- Improved astrometric calibration is based on the Gaia DR1 catalog. Shifts up to 100 arcsec have been correctly identified. 94% of the fields have matches to an external astrometric reference catalog.
- The scatter in magnitudes is measured using the median absolute deviation (MAD) of the differences from the median magnitude for more robust estimates.
- Release: 1.0 (September 2019)
Reference: Bonanos et. al. 2019
The Hubble Catalog of Variables (HCV) is the first full, homogeneous, catalog of variable sources found in the Hubble Source Catalog (HSC), which is built out of publicly available images obtained with the WFPC2, ACS and WFC3 instruments onboard the Hubble Space Telescope. The HCV is the deepest catalog of variables available. It includes variable stars in our Galaxy and nearby galaxies, as well as transients and variable active galactic nuclei. In total, the HCV includes 84,428 candidate variable sources (out of 3.7 million HSC sources that were searched for variability) with V ≤ 27 mag; for 11,115 of them the variability is detected in more than one filter. The data points in a light curve range from 5 to 120, the time baseline ranges from under a day to over 15 years, while ∼8% of variables have amplitudes in excess of 1 mag.
For more details, see About the Hubble Catalog of Variables.