AR 14553 (Archival Research)

Thu Jul 25 14:20:46 GMT 2024

Principal Investigator: Gabriel Brammer
PI Institution: University of Copenhagen, Niels Bohr Institute
Investigators (xml)

Title: Grizli: The Grism redshift & Line Database for HST WFC3/IR Spectroscopy
Cycle: 24

The HST archive contains roughly 0.7 square degrees of coverage with the WFC3/IR grism elements, providing low spectral resolution / high spatial resolution slitless spectroscopy over the range 0.8--1.7 microns. The archive represents a heterogeneous mix of large, uniform programs and a variety of smaller programs focusing on more specifically selected targets such as galaxy overdensities and fields around distant quasars. Only the 3D-HST spectra---representing just 20% of the archival holdings in just the redder G141 grism---have been fully processed systematically and automatically. Here we propose the "Grizli" project to democratize access to WFC3/IR slitless spectroscopy and provide uniform processing, redshift and emission line measurements of the full WFC3 G102+G141 spectral archive. Novel benefits of the Grizli processing include 1) Increasing the areal coverage of catalogued redshift and line measurements by a factor of five, 2) Providing reduced spectra and simultaneous fits derived from both WFC3/IR grisms, and 3) Combining spectra in deep areas observed at multiple position angles. The uniform processing of the grism archive and rest-frame optical spectra for galaxies at 0.2 < z < 3.5 will enable myriad scientific applications of the rich dataset. Among them we will focus on constraining the dust extinction towards HII regions in distant star-forming galaxies and determining robust emission line luminosity functions to help inform planning of future space-based cosmology missions such as WFIRST. All Legacy data products and the software tools used to generate them will be made freely available through the Hubble Legacy Archive.