Fermi gamma-ray "bubbles" from stochastic acceleration of electrons.
Gamma-ray data from Fermi Large Area Telescope reveal a bilobular structure extending up to ∼50° above and below the Galactic Center. It has been argued that the gamma rays arise from hadronic interactions of high-energy cosmic rays which are advected out by a strong wind, or from inverse-Compton sc...
| Main Authors: | , |
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| Format: | Journal article |
| Language: | English |
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2011
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| _version_ | 1826269644589105152 |
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| author | Mertsch, P Sarkar, S |
| author_facet | Mertsch, P Sarkar, S |
| author_sort | Mertsch, P |
| collection | OXFORD |
| description | Gamma-ray data from Fermi Large Area Telescope reveal a bilobular structure extending up to ∼50° above and below the Galactic Center. It has been argued that the gamma rays arise from hadronic interactions of high-energy cosmic rays which are advected out by a strong wind, or from inverse-Compton scattering of relativistic electrons accelerated at plasma shocks present in the bubbles. We explore the alternative possibility that the relativistic electrons are undergoing stochastic 2nd-order Fermi acceleration by plasma wave turbulence through the entire volume of the bubbles. The observed gamma-ray spectral shape is then explained naturally by the resulting hard electron spectrum modulated by inverse-Compton energy losses. Rather than a constant volume emissivity as in other models, we predict a nearly constant surface brightness, and reproduce the observed sharp edges of the bubbles. |
| first_indexed | 2024-03-06T21:28:18Z |
| format | Journal article |
| id | oxford-uuid:43d5ff58-1b35-4266-a19e-4942f781005e |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T21:28:18Z |
| publishDate | 2011 |
| record_format | dspace |
| spelling | oxford-uuid:43d5ff58-1b35-4266-a19e-4942f781005e2022-03-26T14:57:52ZFermi gamma-ray "bubbles" from stochastic acceleration of electrons.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:43d5ff58-1b35-4266-a19e-4942f781005eEnglishSymplectic Elements at Oxford2011Mertsch, PSarkar, SGamma-ray data from Fermi Large Area Telescope reveal a bilobular structure extending up to ∼50° above and below the Galactic Center. It has been argued that the gamma rays arise from hadronic interactions of high-energy cosmic rays which are advected out by a strong wind, or from inverse-Compton scattering of relativistic electrons accelerated at plasma shocks present in the bubbles. We explore the alternative possibility that the relativistic electrons are undergoing stochastic 2nd-order Fermi acceleration by plasma wave turbulence through the entire volume of the bubbles. The observed gamma-ray spectral shape is then explained naturally by the resulting hard electron spectrum modulated by inverse-Compton energy losses. Rather than a constant volume emissivity as in other models, we predict a nearly constant surface brightness, and reproduce the observed sharp edges of the bubbles. |
| spellingShingle | Mertsch, P Sarkar, S Fermi gamma-ray "bubbles" from stochastic acceleration of electrons. |
| title | Fermi gamma-ray "bubbles" from stochastic acceleration of electrons. |
| title_full | Fermi gamma-ray "bubbles" from stochastic acceleration of electrons. |
| title_fullStr | Fermi gamma-ray "bubbles" from stochastic acceleration of electrons. |
| title_full_unstemmed | Fermi gamma-ray "bubbles" from stochastic acceleration of electrons. |
| title_short | Fermi gamma-ray "bubbles" from stochastic acceleration of electrons. |
| title_sort | fermi gamma ray bubbles from stochastic acceleration of electrons |
| work_keys_str_mv | AT mertschp fermigammaraybubblesfromstochasticaccelerationofelectrons AT sarkars fermigammaraybubblesfromstochasticaccelerationofelectrons |