Since early 2016 (HST Cycle 24), the astronomical community has been offered a novel way of mining data from the UV spectrographs onboard HST through the Hubble Spectroscopic Legacy Archive (HSLA) on MAST. The HSLA provides quick-look spectra for individual COS/FUV exposures, co-added COS/FUV spectra, and individual calibrated COS/NUV exposures, all publicly-available in MAST. These data are packaged into 'smart archives' according to target type and scientific themes to facilitate the construction of archival samples for common science uses.
We announce a new release of the HSLA. This release now contains COS/NUV co-added spectra along with all newly-public COS/FUV and COS/NUV spectra, individual and co-added, since April 2017. The COS/FUV co-added products now include LP3 and LP4, in addition to LP1 and LP2, with updated dispersion solutions. The COS/FUV blue modes (G130M/1055, 1096 and 1222) are also included in the HSLA co-added COS/FUV spectra. This release also captures the latest updates to the COS/FUV and COS/NUV reference files. In particular, this release of the HSLA was timed to inform proposers in preparation for the HST Cycle 26 call for proposals.
The HSLA products are available on MAST, together with a description of their contents. Questions and feedback about the HSLA data products can be sent to email@example.com. Additional questions on accessing HSLA data may be directed to the Archive Helpdesk.
Version 3 of the Hubble Source Catalog (HSC) was released on July 5, 2018. The Hubble Source Catalog 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. Powerful user interfaces combined with accurate photometry and astrometry make the data suitable for a wide range of science including studies of star and galaxy populations, variability, proper motions, and much more.
In addition to many improvements in photometry and astrometry, the HSCv3 contains 540 million measurements of 108 million different objects, an increase of 40% and 20% respectively compared with HSCv2. Highlights from Version 3 also include:
The source lists include 25% more ACS/WFC images and more than twice as many WFC3 images compared with the HSCv2 release. ACS and WFC3 data that were public as of 2017 October 1 are included (HLA DR10).
The photometric quality in the source lists is significantly improved due both to the alignment algorithm used to match exposures and filters in the HLA image processing and to improved algorithms for Source Extractor photometry (particularly near the edges of images). See Figure 1 for an example of the improvement in globular cluster M4.
The absolute astrometric calibration is now based on the Gaia DR1 catalog. The relative astrometry is also improved, with a typical scatter for the entire catalog of 3 milliarcsec (see Figure 2). The astrometric accuracy is even better for brighter sources that are not near the 5-sigma catalog detection limit.
The scatter in magnitudes is measured using the median absolute deviation (MAD) of the differences from the median magnitude. This is more robust and less sensitive to outliers than the RMS used in previous versions.
Data from Gaia Data Release 2 (DR2) is now available through MAST. DR2 adds another half-billion sources to the original DR1 catalog (an almost 50% increase), with 5-parameter astrometric solutions for over 75% of all sources. MAST is an affiliated data archive for the Gaia mission, which is operated by the European Space Agency. A list of participating institutions can be found here.
Users have a number of different ways to access Gaia DR2 data through MAST. Firstly, is the MAST Portal. By navigating to the Portal and selecting “MAST Catalogs” from the Collections drop-down menu, the Mission selection will now have an option for "Gaia (DR2)". From here, one can perform cone-searches around RA/Dec coordinates or object names. In addition to displaying the catalog information, sources will also be displayed graphically in the Astroview panel.
More powerful SQL queries can be carried out by logging on into our CasJobs Interface and selecting the GAIA_DR2 database from the Context menu in the Query tab. To find out which tables are accessible and what their column information is, you can select the GAIA_DR2 database in the MyDB tab. A variety of functions exist in the database to facilitate queries, including cone searches. For example, to perform a search similar to the one above you could write the following in the Query tab: select top(100) F.distance, T.* from fGetNearbyObjEq(273., -32., 0.005*60) F join GAIApublicVOview T on T.source_id = F.objID Users can also upload tables to CasJobs and perform cross-matches across the various catalogs we offer.
The WFCJ (Wide-Field Coverage for Juno) program has added an updated "version 2" zonal wind profile for perijove 3, new zonal wind profiles for perijoves 4 and 12, and global maps for perijove 12. Additional details and data download options can be found on their landing page.
If you are thinking about contributing an HLSP of your own, please fill out the HLSP Interest Form to get started. HLSPs archived on MAST enjoy permanent hosting space, additional visibility, and, often, increased citation rates. Any additional questions on the process can be sent to the Archive Helpdesk or to firstname.lastname@example.org. We look forward to working with you!
This newsletter is a MAST publication produced by Jonathan Hargis, Peter Forshay, and Randy Thompson, on behalf of the entire MAST staff, who welcome your comments and suggestions.
The Mikulski Archive for Space Telescopes (MAST) is a NASA funded project to support and provide to the astronomical community a variety of astronomical data archives, with the primary focus on scientifically related data sets in the optical, ultraviolet, and near-infrared parts of the spectrum. MAST is located at the Space Telescope Science Institute (STScI).