Faculty meeting - 13 Dec 2006 The Hubble Legacy Archive Harald Kuntschner & ST-ECF staff 13 December 2006

Faculty meeting - 13 Dec 2006 HST data status Very good, world-wide access to HST data via the WEB - mostly observation based search HST pipelines provide scientific useful products for most modes (most of instrumental signature removed) The fraction of science derived from HST archive data is rising rapidly After SM4 (2008), Hubble will be in its last phase of operation HST data will remain competitive for many years (decades) to come

Faculty meeting - 13 Dec 2006 All perfect? For example, the absolute astrometry only good to ~1” HST spectroscopy products limited How to preserve technical expertise and knowledge beyond HST lifetime? Expertise peaks towards the end of a project, but then dissipates very quickly How to enable more scientific archive searches (e.g., give me all spectra in a given area of sky, with S/N greater than 30 and resolving power smaller than 100 … ) How to utilize HST data in 10+ years? Preservation for the future.

Faculty meeting - 13 Dec 2006 Goal of the HLA The main goal is to optimize the science return from HST data and the preservation of the data products long into the future by capturing the current scientific and technical expertise in High Level Data products. –Also provide efficient data discovery and access services –The project will be carried out on best effort basis so <100% of the currently available products will be transformed to a higher level

Faculty meeting - 13 Dec 2006 What are High Level Data Products? Instrumental signature removed - Science “ready” Good calibration to the limits of the instrument and observatory Good characterization of spatial, spectral, temporal and observable (flux) axes including errors Scientific and world-wide understandable publication and description of the data (VO format?) Supported by documentation about production process etc.

Faculty meeting - 13 Dec 2006 Who’s in the game? The Space Telescope Science Institute (STScI), the Canadian Astronomy Data Centre (CADC) and the ST-ECF are working together to build the Hubble Legacy Archive A high level HLA agreement, to ensure standardization of HLA-related products, is being finalized

Faculty meeting - 13 Dec 2006 HLA science products include Enhanced image products (stacked, calibrated, drizzled images, mosaics, …) Online access (“seconds not hours or days”; an analog - difference between the library and ADS) Improved Astrometry (better cross-matching, smaller error boxes) Footprints (easier way to browse, identify datasets, and download) Cutouts (fast access; enable real-time services to be developed) Source Catalogs (quick look facility, allow many users to skip the “analysis” step and go straight to the “interpretation” step) Calibrated spectra from HST slitless spectroscopy (e.g., ACS grism/prism, NICMOS grism)

Faculty meeting - 13 Dec 2006 ST-ECF efforts The main focus is on the provision of science (and VO) ready spectra derived from HST slitless spectroscopy Currently working on a pilot study using NICMOS G141 slitless data ( µm)

Faculty meeting - 13 Dec 2006 Main data sources: Further available: NIC3/G096, NIC3/G206, STIS/G750L, STIS/PRISM, WFPC1/GRISM After SM4: WFC – 10500G800L 20 – 3900PR200L 10 – 1800PR110L 7 – 1800PR130L – 10500G800L Dispersion [Å/pixel] Wavelength Range [Å] Disperser 202x202 29x26 35x31 29x26 FOV [“] ACS/WFC ACS/HRC ACS/SBC ACS/HRC Channel – 19000G14151x51NIC3 HST slitless spectroscopy

Faculty meeting - 13 Dec 2006 Images with (most of) the detector characteristics removed are available from archive How to produce calibrated spectra from here? Direct image Grism image The NICMOS G141 pilot study

Faculty meeting - 13 Dec 2006 PHLAG – the Pipeline for the Hubble Legacy Archive Grism data Data preparation - Identification of reducible data junks (associations) Data retrieval from archive Additional background subtraction Direct image combination and object detection Spectral extraction with aXe tool (using a calibration of wavelength scale and direct object position) Quality control and SV Full characterization and VO production (Meta Data) Data ingestion into a searchable archive

Faculty meeting - 13 Dec … Individual grism spectra Coadded grism spectrum 2.0 µm 1.0 µm Detector defects

Faculty meeting - 13 Dec 2006 Conclusions The HLA project will significantly enhance the value and usability of the archived data (and future data: WFC3, COS) Technical knowledge and science expertise is preserved within the products Now is the time to start this process since e.g., JWST will soon draw a lot of resources