3D-HST

3D-HST

3D-HST is a near-infrared spectroscopic treasury program executed with the Hubble Space Telescope using the Wide Field Camera 3 grism to obtain slitless spectroscopy across key extragalactic legacy fields. The survey targeted the COSMOS field, AEGIS field, GOODS-N, GOODS-S, and UKIDSS Ultra Deep Survey to complement deep imaging from programs such as CANDELS and to provide redshifts, emission-line measurements, and continuum spectra for studies of galaxy evolution. 3D-HST data have been used alongside observations from facilities including the Spitzer Space Telescope, Chandra X-ray Observatory, Atacama Large Millimeter/submillimeter Array, and the Very Large Telescope.

Overview

3D-HST was conceived as a spectroscopic complement to imaging campaigns like CANDELS, GOODS, COSMOS, UDS, and AEGIS to enable population studies of galaxies spanning redshift ranges probed by Hubble Ultra Deep Field and wide surveys. The program leveraged heritage from surveys such as DEEP2 Galaxy Redshift Survey, Sloan Digital Sky Survey, VIMOS VLT Deep Survey, and the zCOSMOS project, integrating grism spectroscopy to measure emission lines like Hα and [O III] in systems previously studied by Herschel Space Observatory and Spitzer. 3D-HST delivered spectroscopic redshifts that were cross-compared with photometric catalogs from CANDELS, UltraVISTA, MOIRCS Deep Survey, and ground-based campaigns led by institutions including the Max Planck Institute for Astronomy and the National Optical-Infrared Astronomy Research Laboratory.

Survey Design and Instruments

The 3D-HST program used the Hubble Space Telescope's Wide Field Camera 3 infrared grisms G141 and G102 to collect slitless spectra over wavelength ranges that capture diagnostic lines for galaxies at z ~ 0.7–3.5. Observations were planned in coordination with imaging from CANDELS and ancillary data from the Chandra Deep Field South, Subaru Telescope, Keck Observatory, and the Gemini Observatory to improve spectral extraction and line identification. The survey strategy balanced depth and area by mosaicking fields employed by GOODS, COSMOS, and UDS while exploiting parallel programs run by teams affiliated with the Space Telescope Science Institute, European Southern Observatory, and the California Institute of Technology.

Data Reduction and Catalogs

3D-HST adopted specialized reduction pipelines and extraction tools developed in collaboration with groups at Princeton University, Columbia University, University of California, Santa Cruz, and the Max Planck Society to handle slitless data decontamination and background subtraction. The project produced public catalogs linking grism redshifts and emission-line fluxes to photometric measurements from CANDELS, 3D-DASH, SHELA, UKIDSS, and ground-based surveys such as CFHT Legacy Survey and Subaru Deep Field. Ancillary spectroscopic redshifts from Keck DEIMOS, VLT FORS2, and Magellan Telescopes were integrated into master catalogs used by investigators at Harvard University, Yale University, University of Cambridge, University of Toronto, and the National Radio Astronomy Observatory.

Scientific Results

3D-HST enabled precise measurements of star-formation rates, mass assembly, and structural evolution by providing rest-frame optical spectra for large samples cross-matched to imaging from Hubble Ultra Deep Field and wide surveys such as COSMOS2015. Key results included characterization of the star-forming main sequence first highlighted in studies by groups at Max Planck Institute for Astrophysics and National Astronomical Observatory of Japan, mapping the stellar mass function evolution consistent with analyses from SDSS at low redshift and UltraVISTA at high redshift. The dataset informed studies of quenching mechanisms linked to environments sampled in COSMOS and GOODS and supported investigations into active galactic nuclei identified with Chandra and follow-up spectroscopy from Keck Observatory and VLT. 3D-HST spectra were used to measure metallicity trends complementary to findings from Sloan Digital Sky Survey and to study kinematic signatures when combined with integral-field observations from KMOS and SINFONI.

Legacy and Impact

The 3D-HST catalogs and software influenced subsequent surveys and missions, serving as pathfinders for programs on the James Webb Space Telescope and surveys undertaken by Euclid and the Nancy Grace Roman Space Telescope. The project fostered collaborations among institutions such as Space Telescope Science Institute, University of California, Berkeley, University of Oxford, Max Planck Institute for Extraterrestrial Physics, and major ground-based observatories. Legacy products from 3D-HST continue to be incorporated into multiwavelength databases used by researchers at Princeton University, Columbia University, Harvard–Smithsonian Center for Astrophysics, and the European Southern Observatory, shaping our understanding of galaxy formation across cosmic time.

Category:Astronomical surveys