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 2008

- expected lifetime > 201312 instrumentsFOC, 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 DATAimaging (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

HST Slitless DataHST focal plane sky distribution of

HST slitless spectroscopic data

HST Slitless Data

4 May 2006 Hubble Legacy Archive 10

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 2006 Hubble Legacy Archive 11

GoalsWe 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 2006 Hubble Legacy Archive 12

Goals IIWe 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

spectra displayed in VOspec

undispersed image displayed in Aladin

spectrum selector

ConclusionsThe ST-ECF Hubble Legacy Archive will contain:• ~ 104near IR spectra 1.1 to 1.9 µm (NICMOS G141)

o unique wavelength coverageo deep unbiased survey

• ~ 105 optical spectra 6000 to 10000 Å (ACS WF)

o deep, wide-angle spectroscopic survey• quasi-randomly distributed over the sky• best quality at high galactic latitude