Countless astronomical breakthroughs owe their success to data from NASA’s Hubble Space Telescope, which has been observing the cosmos since 1990. In particular, Hubble is the largest current space telescope that observes the sky in the ultraviolet (UV) spectrum — and with no comparable ultraviolet space instruments planned for the near future, these data are particularly important. 

To make it easier for researchers to access UV data from Hubble, the Space Telescope Science Institute (STScI) team created the Hubble Spectroscopic Legacy Archive (HSLA). For about eight years, the archive only contained data from one of Hubble’s spectrographic instruments — the Cosmic Origins Spectrograph — and has been difficult to update with new data automatically. However, on November 14, STScI launched a new and improved HSLA that will be updated automatically any time new observations are received. This new archive also includes data from Hubble’s other spectrograph, the Space Telescope Imaging Spectrograph. 

“Even if you have a unique capability like Hubble’s UV observations, it's only as good as how easily you can access the information from it,” said HSLA team lead John Debes, a European Space Agency/Associated Universities for Research in Astronomy scientist at STScI. “I really like that we are making this accessible, from the earliest career people all the way to the power users.”

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When data arrive in HSLA, the new system automatically uses information from the Set of Identifications, Measurements, and Bibliography for Astronomical Data (SIMBAD), the NASA Exoplanet Archive, and the NASA/IPAC Extragalactic Database (NED) to identify each astronomical object in the observation. By building on these existing open data archives, the HSLA team was able to create powerful new classification features for their archive’s users. 

"If there was not this push for open data, reproducibility, and open-source code, we would have had to reinvent the wheel at every step,” Debes said. “That saved a huge amount of time.” 

HSLA allows users to run searches for types of astronomical objects, rather than a specific target. For example, if a scientist wants to study white dwarfs as a population, they can pull up all the white dwarf spectra in the archive. For individual objects, users can see “quick look” spectra that combine all observations of the object together, making it easier to understand the object’s characteristics at a glance. 

The HSLA team has also released the code for coadding spectra, as well as tools for creating custom coadditions, smoothing the path for users to tailor their process for their research. The advances made by the new HSLA could inform efforts to make other astrophysics data archives more searchable in the future. 

Access the new HSLA archive on the MAST website.