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Title: Analyzing the gamma-ray sky with wavelets

Abstract

We analyze the gamma-ray sky at energies of 0.5 to 50 GeV using the undecimated wavelet transform on the sphere. Focusing on the inner 60°×60° of the sky, we identify and characterize four separate residuals beyond the expected Milky Way diffuse emission. We detect the Fermi bubbles, finding compelling evidence that they are diffuse in nature and contain very little small-scale structure. We detect the “cocoon” inside the southern bubble, and we also identify its northern counterpart above 2 GeV. The northern cocoon lies along the same axis but is ~30% dimmer than the southern one. We characterize the Galactic center excess, which we find extends up to 20° in |b|. At latitudes |b|≤5° we find evidence for power in small angular scales that could be the result of point-source contributions, but for |b|≥5° the Galactic center excess is dominantly diffuse in its nature. Our findings show either that the Galactic center excess and Fermi bubbles connect smoothly or that the bubbles brighten significantly below 15° in latitude. We find that the Galactic center excess appears off-center toward negative ℓ. Additionally, we find and characterize two emissions along the Galactic disk centered at ℓ≃+25° and -20°. Furthermore, these emissions are significantly more elongatedmore » along the Galactic disk than the Galactic center excess.« less

Authors:
 [1];  [1];  [2];  [2]
  1. The Johns Hopkins Univ., Baltimore, MD (United States)
  2. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1436722
Alternate Identifier(s):
OSTI ID: 1463937
Report Number(s):
arXiv:1803.01952; FERMILAB-PUB-18-057-A-T
Journal ID: ISSN 2470-0010; PRVDAQ; 1658780; TRN: US1900226
Grant/Contract Number:  
AC02-07CH11359; SC0007859
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 98; Journal Issue: 4; Journal ID: ISSN 2470-0010
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Balaji, Bhaskaran, Cholis, Ilias, Fox, Patrick J., and McDermott, Samuel D. Analyzing the gamma-ray sky with wavelets. United States: N. p., 2018. Web. doi:10.1103/PhysRevD.98.043009.
Balaji, Bhaskaran, Cholis, Ilias, Fox, Patrick J., & McDermott, Samuel D. Analyzing the gamma-ray sky with wavelets. United States. doi:10.1103/PhysRevD.98.043009.
Balaji, Bhaskaran, Cholis, Ilias, Fox, Patrick J., and McDermott, Samuel D. Fri . "Analyzing the gamma-ray sky with wavelets". United States. doi:10.1103/PhysRevD.98.043009. https://www.osti.gov/servlets/purl/1436722.
@article{osti_1436722,
title = {Analyzing the gamma-ray sky with wavelets},
author = {Balaji, Bhaskaran and Cholis, Ilias and Fox, Patrick J. and McDermott, Samuel D.},
abstractNote = {We analyze the gamma-ray sky at energies of 0.5 to 50 GeV using the undecimated wavelet transform on the sphere. Focusing on the inner 60°×60° of the sky, we identify and characterize four separate residuals beyond the expected Milky Way diffuse emission. We detect the Fermi bubbles, finding compelling evidence that they are diffuse in nature and contain very little small-scale structure. We detect the “cocoon” inside the southern bubble, and we also identify its northern counterpart above 2 GeV. The northern cocoon lies along the same axis but is ~30% dimmer than the southern one. We characterize the Galactic center excess, which we find extends up to 20° in |b|. At latitudes |b|≤5° we find evidence for power in small angular scales that could be the result of point-source contributions, but for |b|≥5° the Galactic center excess is dominantly diffuse in its nature. Our findings show either that the Galactic center excess and Fermi bubbles connect smoothly or that the bubbles brighten significantly below 15° in latitude. We find that the Galactic center excess appears off-center toward negative ℓ. Additionally, we find and characterize two emissions along the Galactic disk centered at ℓ≃+25° and -20°. Furthermore, these emissions are significantly more elongated along the Galactic disk than the Galactic center excess.},
doi = {10.1103/PhysRevD.98.043009},
journal = {Physical Review D},
issn = {2470-0010},
number = 4,
volume = 98,
place = {United States},
year = {2018},
month = {8}
}

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