Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View

Fuente: arXiv
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Auteurs principaux: Murthy, Jayant, Shull, J. Michael, Postman, Marc, Parker, Joel Wm., Redfield, Seth, Cunningham, Nathaniel, Gladstone, G. Randall, Pineau, Jon P., Brandt, Pontus, Verbiscer, Anne J., Singer, Kelsi N., Weaver, Harold A., Henry, Richard C., Stern, S. Alan
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Publié: 2025
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author Murthy, Jayant
Shull, J. Michael
Postman, Marc
Parker, Joel Wm.
Redfield, Seth
Cunningham, Nathaniel
Gladstone, G. Randall
Pineau, Jon P.
Brandt, Pontus
Verbiscer, Anne J.
Singer, Kelsi N.
Weaver, Harold A.
Henry, Richard C.
Stern, S. Alan
author_facet Murthy, Jayant
Shull, J. Michael
Postman, Marc
Parker, Joel Wm.
Redfield, Seth
Cunningham, Nathaniel
Gladstone, G. Randall
Pineau, Jon P.
Brandt, Pontus
Verbiscer, Anne J.
Singer, Kelsi N.
Weaver, Harold A.
Henry, Richard C.
Stern, S. Alan
contents We present new observations of the cosmic ultraviolet background (CUVB) at high Galactic latitudes ($|b| > 40^{\circ}$), made using the Alice UV spectrograph on board the New Horizons spacecraft. These observations were taken at about 57 AU from the Sun, outside much of the foreground emission affecting previous missions, and allowed a new determination of the spectrum of the CUVB between 912 -- 1100~Å and 1400 -- 1800~Å. We found a linear correlation between the CUVB and the Planck E(B~-~V) with offsets at zero-reddening of $221 \pm 11$ photon units at 1000~Å and $264 \pm 24$ \photu\ at 1500~Å ($4.4 \pm 0.2$ nW m$^{-2}$ sr$^{-1}$ at 1000~Å and $5.3 \pm 0.5$ nW m$^{-2}$ sr$^{-1}$ at 1500~Å). The former is the first firm detection of the offset in the range 912 -- 1100 Å while the latter result confirms previous results from \galex, showing that there is little emission from the Solar System from 1400 -- 1800 Å. About half of the offset may be explained by known sources (the integrated light of unresolved galaxies, unresolved stars, emission from ionized gas, and two-photon emission from warm hydrogen in the halo) with the source of the remaining emission as yet unidentified. There is no detectable emission below the Lyman limit with an upper limit of $3.2 \pm 3.0$ photon units.
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id arxiv_https___arxiv_org_abs_2501_00787
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View
Murthy, Jayant
Shull, J. Michael
Postman, Marc
Parker, Joel Wm.
Redfield, Seth
Cunningham, Nathaniel
Gladstone, G. Randall
Pineau, Jon P.
Brandt, Pontus
Verbiscer, Anne J.
Singer, Kelsi N.
Weaver, Harold A.
Henry, Richard C.
Stern, S. Alan
Astrophysics of Galaxies
We present new observations of the cosmic ultraviolet background (CUVB) at high Galactic latitudes ($|b| > 40^{\circ}$), made using the Alice UV spectrograph on board the New Horizons spacecraft. These observations were taken at about 57 AU from the Sun, outside much of the foreground emission affecting previous missions, and allowed a new determination of the spectrum of the CUVB between 912 -- 1100~Å and 1400 -- 1800~Å. We found a linear correlation between the CUVB and the Planck E(B~-~V) with offsets at zero-reddening of $221 \pm 11$ photon units at 1000~Å and $264 \pm 24$ \photu\ at 1500~Å ($4.4 \pm 0.2$ nW m$^{-2}$ sr$^{-1}$ at 1000~Å and $5.3 \pm 0.5$ nW m$^{-2}$ sr$^{-1}$ at 1500~Å). The former is the first firm detection of the offset in the range 912 -- 1100 Å while the latter result confirms previous results from \galex, showing that there is little emission from the Solar System from 1400 -- 1800 Å. About half of the offset may be explained by known sources (the integrated light of unresolved galaxies, unresolved stars, emission from ionized gas, and two-photon emission from warm hydrogen in the halo) with the source of the remaining emission as yet unidentified. There is no detectable emission below the Lyman limit with an upper limit of $3.2 \pm 3.0$ photon units.
title Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2501.00787