Early Results from GLASS-JWST. VI. Extreme Rest-optical Equivalent Widths Detected in NIRISS Wide Field Slitless Spectroscopy
Kristan Boyett, Sara Mascia, L. Pentericci, Nicha Leethochawalit, Michele Trenti, Gabriel Brammer, Guido Roberts-Borsani, Victoria Strait, Tommaso Treu, Maruša Bradač, Karl Glazebrook, Ana Acebrón, P. Bergamini, Antonello Calabrò, M. Castellano, A. Fontana, C. Grillo, Alaina Henry, Tucker Jones, Danilo Marchesini, Charlotte Mason, A. Mercurio, Takahiro Morishita, Themiya Nanayakkara, P. Rosati, Claudia Scarlata, E. Vanzella, Benedetta Vulcani, Xin Wang, Chris J. Willott
Abstract
Abstract Wide Field Slitless Spectroscopy (WFSS) provides a powerful tool for detecting strong line emission in star-forming galaxies (SFGs) without the need for target preselection. As part of the GLASS-JWST Early Release Science (ERS) program, we leverage the near-infrared wavelength capabilities of NIRISS (1–2.2 μ m) to observe rest-optical emission lines out to z ∼ 3.4, to a depth and with a spatial resolution higher than ever before (H α to z < 2.4; [O iii ]+H β to z < 3.4). In this Letter we constrain the rest-frame [O III ] λ 5007 equivalent width (EW) distribution for a sample of 76 1 < z < 3.4 SFGs in the A2744 Hubble Frontier Field and determine an abundance fraction of extreme emission line galaxies with EW > 750Å in our sample to be 12%. We determine a strong correlation between the measured H β and [O III ] λ 5007 EWs, supporting that the high [O III ] λ 5007 EW objects require massive stars in young stellar populations to generate the high-energy photons needed to doubly ionize oxygen. We extracted spectra for objects up to 2 mag fainter in the near-infrared than previous WFSS studies with the Hubble Space Telescope. Thus, this work clearly highlights the potential of JWST/NIRISS to provide high-quality WFSS data sets in crowded cluster environments.