Background on a low Earth orbit

Macros to compute and visualize the background for a satellite on a Low Earth Orbit (LEO). The model used here and results using these macros are presented in:

P. Cumani, M. Hernanz, J. Kiener, V. Tatischeff, and A. Zoglauer. "Background for a gamma-ray satellite on a low-Earth orbit". Feb 2019. arXiv:1902.06944, doi:10.1007/s10686-019-09624-0.

Please use this reference if you present any result obtain using these classes.

Table of Contents

• Packages
• Description
• Bibliography
• Validity limits

Packages

The macros are written for Python3. It uses the following packages:

• Numpy
• Astropy
• Scipy
• Matplotlib
• Pandas

Description

• LEOBackgroundGenerator.py : contain the definition of the class describing all the background components.
• LATBackground.py : creates the file Data/LATBackground.dat from the Fermi fits file. It needs to be used only if there is a change in the Fermi-LAT background or a change in the areas where the flux is calculated (lines 24-26).
• BackgroundPlotter_All.py : plots all the different components. To be run with a -h (or --help) option to show a help.
• CreateBackgroundSpectrumMEGAlib.py : creates a file describing the spectrum of different components to be used with MEGAlib to define a source. The value of the integral flux, calculated using the appropriate solid angle and to be added to the .source file, is added as a comment inside the newly created file. To be run with a -h (or --help) option to show a help.

Bibliography

The model uses equations/data from:

• Albedo Neutrons:
  • Kole et al. 2015
       doi:10.1016/j.astropartphys.2014.10.002
  • Lingenfelter 1963
       doi:10.1029/JZ068i020p05633
• Cosmic Photons:
  • Türler et al. 2010
       doi:10.1051/0004-6361/200913072
  • Mizuno et al. 2004
       http://stacks.iop.org/0004-637X/614/i=2/a=1113
  • Ackermann et al. 2015
       doi:10.1088/0004-637X/799/1/86
• Galactic Center/Disk:
  • Fermi-LAT collaboration
       https://fermi.gsfc.nasa.gov/ssc/data/analysis/software/aux/gll_iem_v06.fits
• Primary Protons:
  • Aguilar et al. 2015
       doi:10.1103/PhysRevLett.114.171103
• Secondary Protons:
  • Mizuno et al. 2004
       http://stacks.iop.org/0004-637X/614/i=2/a=1113
• Primary Alphas:
  • Aguilar et al. 2015b
       doi:10.1103/PhysRevLett.115.211101
• Primary Electrons:
  • Aguilar et al. 2014
       doi:10.1103/PhysRevLett.113.121102
  • Mizuno et al. 2004
       http://stacks.iop.org/0004-637X/614/i=2/a=1113
• Primary Positrons:
  • Aguilar et al. 2014
       doi:10.1103/PhysRevLett.113.121102
  • Mizuno et al. 2004
       http://stacks.iop.org/0004-637X/614/i=2/a=1113
• Secondary Electrons:
  • Mizuno et al. 2004
       http://stacks.iop.org/0004-637X/614/i=2/a=1113
• Secondary Positrons:
  • Mizuno et al. 2004
       http://stacks.iop.org/0004-637X/614/i=2/a=1113
• Atmospheric Photons:
  • Sazonov et al. 2007
       doi:10.1111/j.1365-2966.2007.11746.x
  • Churazov et al. 2006
       doi:10.1111/j.1365-2966.2008.12918.x
  • Türler et al. 2010
       doi:10.1051/0004-6361/200913072
  • Mizuno et al. 2004
       http://stacks.iop.org/0004-637X/614/i=2/a=1113
  • Abdo et al. 2009
       doi:10.1103/PhysRevD.80.122004

Validity limits

	Orbit Parameters	Energy
Cosmic Photons	Independent	4 keV - 820 GeV
Galactic Photons	Independent	58 MeV - ~513 GeV
Albedo Photons	All LEOs	1 keV - 400 GeV
Primary Protons	Altitude > 100 km	10 MeV - 10 TeV
Primary Alphas	Altitude > 100 km	10 MeV - 10 TeV
Primary Electrons/Positrons	Altitude > 100 km	570 MeV - 429 GeV
Secondary Protons	1.06 ≤ Rcutoff ≤ 12.47	1 MeV - 10 GeV
Secondary Electrons/Positrons	1.06 ≤ Rcutoff ≤ 12.47	1 MeV - 20 GeV
Atmospheric Neutrons	Altitude: ~100 km - ~1000 km / Inclination: < 65°	0.01 eV - ~30 GeV

Validity limits of the different components of the background.

Acknowledgment

This work has been carried out in the framework of the project AHEAD, funded by the European Union