Felix Stoehr

The Hubble Legacy Archive ACS grism data

A public release of slitless spectra, obtained with ACS/WFC and the G800L grism, is presented. Spectra were automatically extracted in a uniform way from 153 archival fields (or “associations”) distributed across the two Galactic caps, covering all observations to 2008. The ACS G800L grism provides a wavelength range of 0.55−1.00 μm, with a dispersion of 40 A/pixel and a resolution of ∼80 A for point-like sources. The ACS G800L images and matched direct images were reduced with an automatic pipeline that handles all steps from archive retrieval, alignment and astrometric calibration, direct image combination, catalogue generation, spectral extraction and collection of metadata. The large number of extracted spectra (73, 581) demanded automatic methods for quality control and an automated classification algorithm was trained on the visual inspection of several thousand spectra. The final sample of quality controlled spectra includes 47 919 datasets (65% of the total number of extracted spectra) for 32 149 unique objects, with a median iAB-band magnitude of 23.7, reaching 26.5 AB for the faintest objects. Each released dataset contains science-ready 1D and 2D spectra, as well as multi-band image cutouts of corresponding sources and a useful preview page summarising the direct and slitless data, astrometric and photometric parameters. This release is part of the continuing effort to enhance the content of the Hubble Legacy Archive (HLA) with highly processed data products which significantly facilitate the scientific exploitation of the Hubble data. In order to characterize the slitless spectra, emission-line flux and equivalent width sensitivity of the ACS data were compared with public ground-based spectra in the GOODS-South field. An example list of emission line galaxies with two or more identified lines is also included, covering the redshift range 0.2−4.6. Almost all redshift determinations outside of the GOODS fields are new. The scope of science projects possible with the ACS slitless release data is large, from studies of Galactic stars to searches for high redshift galaxies.

The ESO science archive: supporting and enhancing science from the La Silla Paranal Observatory

The archive of the La Silla Paranal Observatory is a powerful science resource for the ESO astronomical community. It stores both the raw data generated by all ESO instruments and selected processed (science-ready) data. We present the new capabilities and user services that have recently been developed in order to enhance data discovery and usage in the face of the increasing volume and complexity of the archive holdings. Future plans to extend the new services to processed data from the Atacama Large Millimeter/submillimeter Array (ALMA) are also discussed.

Enhanced Data Discovery Services for the ESO Science Archive

The Messenger 172 – June 2018 the characteristics and limitations of each collection of processed data. This is particularly important, as it enables users to decide whether the data are suitable for their specific science goals. The systematic archive publication of such processed data dates back to 25 July 2011, with the first products produced by the Public Surveys conducted with the Visible and Infrared Survey Telescope for Astronomy (VISTA) infrared camera VIRCAM (Arnaboldi & Retzlaff, 2011). Processed data that were generated at ESO have been available since September 2013. An up-to-date overview of the released data is available online for contributed and pipeline processed data 2, 3.