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Title: FERMI BUBBLES AND BUBBLE-LIKE EMISSION FROM THE GALACTIC PLANE

Abstract

The diffuse gamma-ray sky revealed ''bubbles'' of emission above and below the Galactic plane, symmetric around the center of the Milky Way, with a height of 10 kpc in both directions. At present, there is no convincing explanation for the origin. To understand the role of the Galactic center, one has to study the bubble spectrum inside the disk, a region that has been excluded from previous analyses because of the large foreground. From a novel template fit, which allows a simultaneous determination of the signal and foreground in any direction, we find that bubble-like emission is not only found in the halo, but in the Galactic plane as well, with a width in latitude coinciding with the molecular clouds. The longitude distribution has a width corresponding to the Galactic bar with an additional contribution from the Scutum-Centaurus arm. The energy spectrum of the bubbles coincides with the predicted contribution from CRs trapped in sources (SCRs). Also, the energetics fits well. Hence, we conclude that the bubble-like emission has a hadronic origin that arises from SCRs, and the bubbles in the halo arise from hadronic interactions in advected gas. Evidence for advection is provided by the ROSAT X-rays of hot gasmore » in the bubble region.« less

Authors:
;  [1]
  1. Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, PO Box 6980, D-76049 Karlsruhe (Germany)
Publication Date:
OSTI Identifier:
22364588
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 794; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; BUBBLES; ENERGY SPECTRA; GAMMA RADIATION; HADRONS; MILKY WAY; PARTICLE INTERACTIONS; PHOTON EMISSION; SHOCK WAVES; SYMMETRY; TRAPPING; X RADIATION

Citation Formats

De Boer, Wim, and Weber, Markus. FERMI BUBBLES AND BUBBLE-LIKE EMISSION FROM THE GALACTIC PLANE. United States: N. p., 2014. Web. doi:10.1088/2041-8205/794/1/L17.
De Boer, Wim, & Weber, Markus. FERMI BUBBLES AND BUBBLE-LIKE EMISSION FROM THE GALACTIC PLANE. United States. https://doi.org/10.1088/2041-8205/794/1/L17
De Boer, Wim, and Weber, Markus. 2014. "FERMI BUBBLES AND BUBBLE-LIKE EMISSION FROM THE GALACTIC PLANE". United States. https://doi.org/10.1088/2041-8205/794/1/L17.
@article{osti_22364588,
title = {FERMI BUBBLES AND BUBBLE-LIKE EMISSION FROM THE GALACTIC PLANE},
author = {De Boer, Wim and Weber, Markus},
abstractNote = {The diffuse gamma-ray sky revealed ''bubbles'' of emission above and below the Galactic plane, symmetric around the center of the Milky Way, with a height of 10 kpc in both directions. At present, there is no convincing explanation for the origin. To understand the role of the Galactic center, one has to study the bubble spectrum inside the disk, a region that has been excluded from previous analyses because of the large foreground. From a novel template fit, which allows a simultaneous determination of the signal and foreground in any direction, we find that bubble-like emission is not only found in the halo, but in the Galactic plane as well, with a width in latitude coinciding with the molecular clouds. The longitude distribution has a width corresponding to the Galactic bar with an additional contribution from the Scutum-Centaurus arm. The energy spectrum of the bubbles coincides with the predicted contribution from CRs trapped in sources (SCRs). Also, the energetics fits well. Hence, we conclude that the bubble-like emission has a hadronic origin that arises from SCRs, and the bubbles in the halo arise from hadronic interactions in advected gas. Evidence for advection is provided by the ROSAT X-rays of hot gas in the bubble region.},
doi = {10.1088/2041-8205/794/1/L17},
url = {https://www.osti.gov/biblio/22364588}, journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 794,
place = {United States},
year = {Fri Oct 10 00:00:00 EDT 2014},
month = {Fri Oct 10 00:00:00 EDT 2014}
}