The European Hubble Space Telescope Legacy Archive Wolfram Freudling

The Hubble Space Telescope 1 telescope - currently, 3instruments in operation - repair and service mission SM4 in expected lifetime > instruments FOC, FOS, GHRS, HSP, WF/PC1, ACS, FGS, NICMOS, STIS, WFPC2, COS, WFC3 3 archives

HST archives contain pipeline-reduced science-ready data often requires significant processing before use “difficult” data require significant expertise to process new paradigm: Archive produces high-level Data Products: Hubble Legacy Archive (HLA) also include community contributions collaboration STScI, ST-ECF, CADC

HST DATA imaging (e.g. ACS, WFPC2) single object spectroscopy (STIS) slitless spectroscopy (e.g. ACS, NICMOS)

Slitless Spectroscopy in Space slitless spectroscopy inefficient from ground but in space: –low background –surveys in regions of spectrum which are not accessible from ground (UV, IR) –high angular resolution of HST

Data Examples ACS NICMOS

imagesslitless spectra calibrated images (classical archive) can be used for some science not a useful product object catalogs, parameters from individual images useful parameters (shape, total flux) easy to obtain can not easily be used high level products: stacked images, postage stamps useful as final products useful in combination with extracted spectra extracted parameters, e.g. flux profiles luminosity profiles: easy to produce, highly dependent on application integrated 1d spectra: more difficult to produce, always desired

HST Slitless Data HST focal plane sky distribution of HST slitless spectroscopic data

HST Slitless Data

4 May 2006Hubble Legacy Archive10 Mission Statement “Extract science grade 1d spectra of all isolated objects visible in undispersed images of HST slitless spectrographs using the best possible calibration.”

4 May 2006Hubble Legacy Archive11 Goals We will try: extract 1d spectra (  vs. F) of all easy (high s/n) spectra produce 2d (x vs y ) cutouts of all spectra produce 2d cutouts of corresponding objects on undispersed images extract spectra which are barely visible or noise only as long as there is an object visible on the undispersed image extract spectra for both point sources and extended sources extract spectra at the edge of detector extract spectra affected by bad pixels characterize extracted spectra (noise, continuum level, lines?, …)

4 May 2006Hubble Legacy Archive12 Goals II We will not try: extract spectra of objects without undispersed image deblend overlapping spectra produce validated 2d spectra (  vs y) classify spectra (stellar, extragalactic, QSO, BD, …)

Pipeline for HLA Grism Data: PHLAG poster by Martin Kümmel et al. pipeline extracts spectra from slitless HST spectra

ST-ECF HLA User Interface I Search form Preview with cut outs and spectra

ST-ECF HLA User Interface spectra displayed in VOspec undispersed image displayed in Aladin spectrum selector

Conclusions The ST-ECF Hubble Legacy Archive will contain: ~ 10 4 near IR spectra 1.1 to 1.9 µm (NICMOS G141) o unique wavelength coverage o deep unbiased survey ~ 10 5 optical spectra 6000 to Å (ACS WF) o deep, wide-angle spectroscopic survey quasi-randomly distributed over the sky best quality at high galactic latitude