Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View
We present new observations of the cosmic ultraviolet background (CUVB) at high Galactic latitudes (∣ b ∣ > 40 ^∘ ), 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 affect...
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IOP Publishing
2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-3881/ada4a4 |
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| author | Jayant Murthy J. Michael Shull Marc Postman Joel Wm. Parker Seth Redfield Nathaniel Cunningham G. Randall Gladstone Jon P. Pineau Pontus Brandt Anne J. Verbiscer Kelsi N. Singer Harold A. Weaver Richard C. Henry S. Alan Stern |
| author_facet | Jayant Murthy J. Michael Shull Marc Postman Joel Wm. Parker Seth Redfield Nathaniel Cunningham G. Randall Gladstone Jon P. Pineau Pontus Brandt Anne J. Verbiscer Kelsi N. Singer Harold A. Weaver Richard C. Henry S. Alan Stern |
| author_sort | Jayant Murthy |
| collection | DOAJ |
| description | We present new observations of the cosmic ultraviolet background (CUVB) at high Galactic latitudes (∣ b ∣ > 40 ^∘ ), 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 ± 11 photon units at 1000 Å and 264 ± 24 photon units at 1500 Å (4.4 ± 0.2 nW m ^−2 sr ^−1 at 1000 Å and 5.3 ± 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 the Galaxy Evolution Explorer, showing that there is little emission from the solar system from 1400 to 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 ± 3.0 photon units. |
| format | Article |
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| institution | Kabale University |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj-art-d30a5fb8882d42fbb68d74dd573735bc2025-02-04T15:41:42ZengIOP PublishingThe Astronomical Journal1538-38812025-01-01169210310.3847/1538-3881/ada4a4Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons ViewJayant Murthy0https://orcid.org/0000-0003-4034-5137J. Michael Shull1Marc Postman2https://orcid.org/0000-0002-9365-7989Joel Wm. Parker3https://orcid.org/0000-0002-3672-0603Seth Redfield4https://orcid.org/0000-0003-3786-3486Nathaniel Cunningham5G. Randall Gladstone6https://orcid.org/0000-0003-0060-072XJon P. Pineau7Pontus Brandt8https://orcid.org/0000-0002-4644-0306Anne J. Verbiscer9Kelsi N. Singer10https://orcid.org/0000-0003-3045-8445Harold A. Weaver11Richard C. Henry12S. Alan Stern13https://orcid.org/0000-0001-5018-7537Indian Institute of Astrophysics , Bengaluru 560 034, IndiaDepartment of Astrophysical & Planetary Sciences, CASA, University of Colorado , Boulder, CO 80309, USA; Department of Physics & Astronomy, University of North Carolina , Chapel Hill, NC 27599, USASpace Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USADepartment of Space Studies, Southwest Research Institute , 1301 Walnut Street, Suite 300, Boulder, CO 80302, USAAstronomy Department and Van Vleck Observatory, Wesleyan University , Middletown, CT 06459, USANebraska Wesleyan University , Lincoln, NE, USASouthwest Research Institute , San Antonio, TX 78238, USA; University of Texas at San Antonio , San Antonio, TX 78249, USAStellar Solutions , Aurora, CO 80011, USAThe Johns Hopkins University Applied Physics Laboratory , Laurel, MD 20723-6099, USADepartment of Astronomy, University of Virginia , Charlottesville, VA 22904, USADepartment of Space Studies, Southwest Research Institute , 1301 Walnut Street, Suite 300, Boulder, CO 80302, USAThe Johns Hopkins University Applied Physics Laboratory , Laurel, MD 20723-6099, USAJohns Hopkins University , Department of Physics and Astronomy, Baltimore, 21218, USASouthwest Research Institute , Space Sector, 1301 Walnut Street, Suite 300, Boulder, CO 80302, USAWe present new observations of the cosmic ultraviolet background (CUVB) at high Galactic latitudes (∣ b ∣ > 40 ^∘ ), 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 ± 11 photon units at 1000 Å and 264 ± 24 photon units at 1500 Å (4.4 ± 0.2 nW m ^−2 sr ^−1 at 1000 Å and 5.3 ± 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 the Galaxy Evolution Explorer, showing that there is little emission from the solar system from 1400 to 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 ± 3.0 photon units.https://doi.org/10.3847/1538-3881/ada4a4Extrasolar radiationUltraviolet astronomyUltraviolet sourcesUltraviolet spectroscopyCosmic background radiationDiffuse radiation |
| spellingShingle | Jayant Murthy J. Michael Shull Marc Postman Joel Wm. Parker Seth Redfield Nathaniel Cunningham G. Randall Gladstone Jon P. Pineau Pontus Brandt Anne J. Verbiscer Kelsi N. Singer Harold A. Weaver Richard C. Henry S. Alan Stern Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View The Astronomical Journal Extrasolar radiation Ultraviolet astronomy Ultraviolet sources Ultraviolet spectroscopy Cosmic background radiation Diffuse radiation |
| title | Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View |
| title_full | Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View |
| title_fullStr | Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View |
| title_full_unstemmed | Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View |
| title_short | Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View |
| title_sort | excess ultraviolet emission at high galactic latitudes a new horizons view |
| topic | Extrasolar radiation Ultraviolet astronomy Ultraviolet sources Ultraviolet spectroscopy Cosmic background radiation Diffuse radiation |
| url | https://doi.org/10.3847/1538-3881/ada4a4 |
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