Paper: SKYSURF: Constraints on Zodiacal Light and Extragalactic Background Light through Panchromatic HST All-sky Surface-brightness Measurements: II. First Limits on Diffuse Light at 1.25, 1.4, and 1.6 μm
Authors: Timothy Carleton, Rogier A. Windhorst, Rosalia O'Brien, Seth H. Cohen, Delondrae Carter, Rolf Jansen, Scott Tompkins, Richard G. Arendt, Sarah Caddy, Norman Grogin, Scott J. Kenyon, Anton Koekemoer, John MacKenty, Stefano Casertano, Luke J. M. Davies, Simon P. Driver, Eli Dwek, Alexander Kashlinsky, Nathan Miles, Nor Pirzkal, Aaron Robotham, Russell Ryan, Haley Abate, Hanga Andras-Letanovszky, Jessica Berkheimer, Zak Goisman, Daniel Henningsen, Darby Kramer, Ci'mone Rogers, Andi Swirbul
Figure caption: Summary of astrophysical foreground and background energy relevant to SKYSURF, along with the first SKYSURF measurements at 1.25, 1.37, and 1.53 microns. The left scale indicates the total energy ν. I  ν  in nW m−2 sr−1, and the right scale the corresponding sky-SB in AB-mag arcsec−2 at 1.25 μm (which can be scaled to other wavelengths as indicated). The discrete measurements of D16 from integrated and extrapolated galaxy counts (iEBL+eEBL) (red-filled circles) and other published data are shown. Gray triangles indicate the total EBL measurements (Puget et al. 1996; Dwek & Arendt 1998; Fixsen et al. 1998; Hauser et al. 1998; Lagache et al. 1999; Finkbeiner et al. 2000; Cambrésy et al. 2001; Bernstein et al. 2002; Matsumoto et al. 2005; Dole et al. 2006; Bernstein 2007; Matsumoto et al. 2011; Matsuura et al. 2011; Tsumura et al. 2013; Sano et al. 2020). Also shown are more recent results from the CIBER experiment (purple triangles; Matsuura et al. 2017), Pioneer (light blue points without errors; Matsumoto et al. 2018), and New Horizons (medium and dark blue points with errors; Lauer et al. (2021) and Lauer et al. (2022), which is offset for clarity) that aim to more accurately subtract the zodiacal foreground. All of these measurements require accurate modeling of foreground DGL, and except for Pioneer and New Horizons points, ZL as well. For a more direct comparison with SKYSURF diffuse-light limits, the iEBL level (taken from the respective references) has been subtracted from the CIBER and New Horizons points. Green squares are panchromatic HST sky-SB measurements compared to the solar spectrum. Brown squares indicate the COBE/DIRBE data and the zodiacal dust model of Kelsall et al. (1998). The gray and orange wedges and blue stars are γ-ray blazar EBL constraints from the MAGIC and HESS TeV experiments (MAGIC Collaboration et al. 2008; H. E. S. S. Collaboration et al. 2013). The black line is the sum of the Andrews et al. (2018) EBL models for star formation in spheroids (red), disks (green), and unobscured AGN (purple). The currently achieved calibration+zero-point accuracy in the 1.25–1.6 μm HST sky-SB estimates is ∼4% of the zodiacal sky-SB (Windhorst et al. 2022), as indicated. SKYSURF’s goal is a ≲2%-accurate sky-SB model across the sky at 0.2–1.6 μm wavelengths, to address the discrepancy between the total EBL and the discrete iEBL+eEBL. The brown points are the SKYSURF diffuse light limits, which implicitly subtract discrete iEBL, identified in Table 1. These limits are lower than previous analyses, but still leave room for an isotropic diffuse light component, whether in the solar system or at cosmological distances.