Gamma-ray emission from the Sagittarius Dwarf Spheroidal galaxy due to millisecond pulsars
| Autor: | Crocker, Roland M., Macias, Oscar, Mackey, Dougal, Krumholz, Mark R., Ando, Shin'ichiro, Horiuchi, Shunsaku, Baring, Matthew G., Gordon, Chris, Venville, Thomas, Duffy, Alan R., Yang, Rui-Zhi, Aharonian, Felix, Hinton, J. A., Song, Deheng, Ruiter, Ashley J., Filipović, Miroslav D. |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Nature Astronomy (2022) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1038/s41550-022-01777-x |
| Popis: | The Fermi Bubbles are giant, gamma-ray emitting lobes emanating from the nucleus of the Milky Way discovered in ~1-100 GeV data collected by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope. Previous work has revealed substructure within the Fermi Bubbles that has been interpreted as a signature of collimated outflows from the Galaxy's super-massive black hole. Here we show via a spatial template analysis that much of the gamma-ray emission associated to the brightest region of substructure -- the so-called cocoon -- is likely due to the Sagittarius dwarf spheroidal (Sgr dSph) galaxy. This large Milky Way satellite is viewed through the Fermi Bubbles from the position of the Solar System. As a tidally and ram-pressure stripped remnant, the Sgr dSph has no on-going star formation, but we nevertheless demonstrate that the dwarf's millisecond pulsar (MSP) population can plausibly supply the gamma-ray signal that our analysis associates to its stellar template. The measured spectrum is naturally explained by inverse Compton scattering of cosmic microwave background photons by high-energy electron-positron pairs injected by MSPs belonging to the Sgr dSph, combined with these objects' magnetospheric emission. This finding plausibly suggests that MSPs produce significant gamma-ray emission amongst old stellar populations, potentially confounding indirect dark matter searches in regions such as the Galactic Centre, the Andromeda galaxy, and other massive Milky Way dwarf spheroidals. Comment: Updated to match version accepted for publication in Nature Astronomy (2022). 14 pages main text, 3 main figures, 7 extended data figures. For published version of the paper, see https://rdcu.be/cUZ6X |
| Databáze: | arXiv |
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