THE 3D-HST SURVEY: HUBBLE SPACE TELESCOPE WFC3/G141 GRISM SPECTRA, REDSHIFTS, AND EMISSION LINE MEASUREMENTS FOR ∼100,000 GALAXIES

Abstract

We present reduced data and data products from the 3D-HST survey, a 248-orbit HST Treasury program. The survey obtained WFC3 G141 grism spectroscopy in four of the five CANDELS fields: AEGIS, COSMOS, GOODS-S, and UDS, along with WFC3 H 140 imaging, parallel ACS G800L spectroscopy, and parallel I 814 imaging. In a previous paper, we presented photometric catalogs in these four fields and in GOODS-N, the fifth CANDELS field. Here we describe and present the WFC3 G141 spectroscopic data, again augmented with data from GO-1600 in GOODS-N (PI: B. Weiner). We developed software to automatically and optimally extract interlaced two-dimensional (2D) and one-dimensional (1D) spectra for all objects in the Skelton et al. (2014) photometric catalogs. The 2D spectra and the multi-band photometry were fit simultaneously to determine redshifts and emission line strengths, taking the morphology of the galaxies explicitly into account. The resulting catalog has redshifts and line strengths (where available) for 22,548 unique objects down to  JH 24 IR (79,609 unique objects down to  JH 26 IR ). Of these, 5459 galaxies are at > z 1.5 and 9621 are at < < z 0.7 1.5, where Hα falls in the G141 wavelength coverage. The typical redshift error for  JH 24 IR galaxies is s »´+z 0.003 1 z ( ), i.e., one native WFC3 pixel. The s 3 limit for emission line fluxes of point sources is´-2.1 10 17 erg s −1 cm −2 . All 2D and 1D spectra, as well as redshifts, line fluxes, and other derived parameters, are publicly available.

The eMERGE Survey – I: Very Large Array 5.5 GHz observations of the GOODS-North Field

“…Cowie et al 2001;Wirth et al 2004;Barger et al 2008;Kajisawa et al 2011;Skelton et al 2014;Momcheva et al 2016).…”

“…The z-fitting procedure used in Momcheva et al (2016), based on combining grism and multi-band photometric datasets, provides photometric redshifts for some low redshift (z < ∼ 0.7), and often red and/or faint galaxies, although they might have a spectroscopic redshift in the literature. For these objects, the photometric fit alone provides a more accurate redshift, and the contribution of the grism spectrum to the combined fit is negligible.…”

“…In order to obtain a homogeneous and updated set of redshifts we adopt, when available, the redshifts from the 3D-HST Treasury survey catalogues (Skelton et al 2014;Momcheva et al 2016). GOODS-N is one of the five CAN-DELS fields for which WFC3 G141 spectroscopic data are available.…”

“…GOODS-N is one of the five CAN-DELS fields for which WFC3 G141 spectroscopic data are available. Spectroscopic redshifts are either measured with space-based dispersion grisms (Momcheva et al 2016) or obtained from ground-based slit spectroscopy from the literature (Skelton et al 2014). Photometric redshifts are determined with the EAZY code (Brammer et al 2008) and listed in Skelton et al (2014).…”

The Alma Spectroscopic Survey in the Hubble Ultra Deep Field: Molecular Gas Reservoirs in High-Redshift Galaxies

“…The agreement with available spectroscopic redshifts is typically very good in these cases, with a standard deviation on Skelton et al 2014). In addition, the 3D-HST survey provides HST ACS and WFC3 grism observations of the field, yielding grism redshifts for tens of sources in our pointing (Momcheva et al 2016). Slit spectroscopy for 74 (mostly bright) galaxies in the field is also available (Le Fèvre et al 2005;Skelton et al 2014;Morris et al 2015).…”