New Horizons Observations of the Cosmic Optical Background

Abstract

We used existing data from the New Horizons Long-range Reconnaissance Imager (LORRI) to measure the optical-band (0.4λ0.9 μm) sky brightness within seven high-Galactic latitude fields. The average raw level measured while New Horizons was 42-45 au from the Sun is 33.2±0.5 nW m −2 sr −1 . This is ∼10×as dark as the darkest sky accessible to the Hubble Space Telescope, highlighting the utility of New Horizons for detecting the cosmic optical background (COB). Isolating the COB contribution to the raw total required subtracting scattered light from bright stars and galaxies, faint stars below the photometric detection limit within the fields, and diffuse Milky Way light scattered by infrared cirrus. We removed newly identified residual zodiacal light from the IRIS 100 μm all-sky maps to generate two different estimates for the diffuse Galactic light. Using these yielded a highly significant detection of the COB in the range 15.9±4.2 (1.8 stat., 3.7 sys.)nW m −2 sr −1 to 18.7±3.8 (1.8 stat., 3.3 sys.)nW m −2 sr −1 at the LORRI pivot wavelength of 0.608 μm. Subtraction of the integrated light of galaxies fainter than the photometric detection limit from the total COB level left a diffuse flux component of unknown origin in the range 8.8±4.9 (1.8 stat., 4.5 sys.)nW m −2 sr −1 to 11.9±4.6(1.8 stat., 4.2 sys.)nW m −2 sr −1 . Explaining it with undetected galaxies requires the assumption that the galaxy count faintend slope steepens markedly at V>24 or that existing surveys are missing half the galaxies with V<30.Unified Astronomy Thesaurus concepts: Cosmic background radiation (317); Diffuse radiation (383); Population III stars (1285); Galaxy formation (595)

Three different effects of the same quantum nature

“…The described three effects of low-energy quantum gravity give us a possibility to interpret well known redshifts of remote objects and their additional dimming discovered in 1998, together with a tentative existence of a diffuse cosmic optical background [5], in a very simple unified manner. This description makes unnecessary any expansion of the universe and dark energy.…”

Black Holes as Geometric Distortional Extrema

“…Because the Universe, primordially modeled as a black-body, is at an extreme temperature, the galaxy DG-Hole-energy appears in the "u N-1 mass-energy range" and is off-scale in the Figure. The mass-energy ratio, "Bu (DG_Hole)) mass-energy-to-hole mass-energy", is postulated to be the number of "hole-seeded-galaxies" and equal to 10 11 to 10 12 (references [22,23]). The density of "dark-matter" in the universe, posited as necessary in the presently accepted Universe-model, is not accounted for in this purely "gravitational-mass-energy spectrum" although a "black body" is considered "dark".…”

Anomalous Flux in the Cosmic Optical Background Detected With New Horizons Observations

“…Zemcov et al (2017) produced a "proof of concept" demonstration that New Horizons' LORRI camera (Cheng et al 2008;Weaver et al 2020) should be useful for COB observations, but had to contend with the dearth of useful archival images available at the time for measuring the COB flux. Lauer et al (2021), in contrast, had a rich set of deep images to draw from and conducted a thorough examination of the calibration of New Horizons' LORRI camera for low light-level observations. Based on seven fields, they measured the COB flux to be in the range 15.9 ± 4.2 (1.8 stat., 3.7 sys.)…”