GLOBAL COSMIC-RAY-RELATED LUMINOSITY AND ENERGY BUDGET OF THE MILKY WAY

We use the GALPROP code for cosmic-ray (CR) propagation to calculate the broadband luminosity spectrum of the Milky Way related to CR propagation and interactions in the interstellar medium. This includes γ-ray emission from the production and subsequent decay of neutral pions (π^0), bremsstrahlung, and inverse Compton scattering, and synchrotron radiation. The Galaxy is found to be nearly a CR electron calorimeter, but only if γ-ray emitting processes are taken into account. Synchrotron radiation alone accounts for only one-third of the total electron energy losses with ~10%-20% of the total synchrotron emission from secondary CR electrons and positrons. The relationship between far-infrared and radio luminosity that we find from our models is consistent with that found for galaxies in general. The results will be useful for understanding the connection between diffuse emissions from radio through γ-rays in "normal" (non-active galactic nucleus dominated) galaxies as well as for estimating the broadband extragalactic diffuse background from these kinds of galaxies.

[1]  Igor V. Moskalenko,et al.  Cosmic-Ray Propagation and Interactions in the Galaxy , 2007 .

[2]  L. Sironi,et al.  THE EDDINGTON LIMIT IN COSMIC RAYS: AN EXPLANATION FOR THE OBSERVED LACK OF LOW-MASS RADIO-LOUD QUASARS AND THE M•–M⋆ RELATION , 2009, 0902.1181.

[3]  A. Strong,et al.  Propagation of Cosmic-Ray Nucleons in the Galaxy , 1998, astro-ph/9807150.

[4]  L. Kewley,et al.  An Initial Look at the Far-Infrared-Radio Correlation within Nearby Star-forming Galaxies Using the Spitzer Space Telescope , 2005, astro-ph/0510227.

[5]  T Glanzman,et al.  Fermi large area telescope measurements of the diffuse gamma-ray emission at intermediate galactic latitudes. , 2009, Physical Review Letters.

[6]  V. Pavlidou,et al.  Imprint of galaxy clustering in the cosmic gamma‐ray background , 2009, 0908.3890.

[7]  A broadband study of galactic dust emission , 2006, astro-ph/0611606.

[8]  F. Camilo,et al.  Young Neutron Stars and Their Environments , 2004 .

[9]  N. Odegard,et al.  A Three-dimensional Decomposition of the Infrared Emission from Dust in the Milky Way , 1997 .

[10]  T Glanzman,et al.  Spectrum of the isotropic diffuse gamma-ray emission derived from first-year Fermi Large Area Telescope data. , 2010, Physical review letters.

[11]  M. Yun,et al.  Radio Properties of Infrared-selected Galaxies in the IRAS 2 Jy Sample , 2001, astro-ph/0102154.

[12]  K. Ferrière.  The interstellar environment of our galaxy , 2001, astro-ph/0106359.

[13]  V. Schönfelder,et al.  The Cosmic-Ray Luminosity of the Galaxy , 2002 .

[14]  R. Mewaldt,et al.  Measurement of the Secondary Radionuclides 10Be, 26Al, 36Cl, 54Mn, and 14C and Implications for the Galactic Cosmic-Ray Age , 2001 .

[15]  E. Ramirez-Ruiz,et al.  The Eddington Limit in Cosmic Rays: An Explanation for the Observed Faintness of Starbursting Galaxies , 2006, astro-ph/0609796.

[16]  Q. Yuan,et al.  GALACTIC DIFFUSE GAMMA RAYS—RECALCULATION BASED ON NEW MEASUREMENTS OF THE COSMIC ELECTRON SPECTRUM , 2009, 0908.1236.

[17]  Donald P. Cox,et al.  THE THREE-PHASE INTERSTELLAR MEDIUM REVISITED , 2005 .

[18]  Caleb A. Scharf.  Optimal Chandra and XMM-Newton Bandpasses for Detecting Low-Temperature Groups and Clusters of Galaxies , 2002 .

[19]  M. Frailis,et al.  FERMI LAT OBSERVATION OF DIFFUSE GAMMA RAYS PRODUCED THROUGH INTERACTIONS BETWEEN LOCAL INTERSTELLAR MATTER AND HIGH-ENERGY COSMIC RAYS , 2009, 0908.1171.

[20]  Jean-Luc Starck,et al.  FERMI OBSERVATIONS OF CASSIOPEIA AND CEPHEUS: DIFFUSE GAMMA-RAY EMISSION IN THE OUTER GALAXY , 2009, 0912.3618.

[21]  H. Freudenreich.  A COBE Model of the Galactic Bar and Disk , 1998 .

[22]  O. Reimer,et al.  Diffuse Galactic Continuum Gamma Rays: A Model Compatible with EGRET Data and Cosmic-Ray Measurements , 2004, astro-ph/0406254.

[23]  A. Strong,et al.  Observations of the Li, Be, and B isotopes and constraints on cosmic-ray propagation , 2006, astro-ph/0611301.

[24]  A. Strong,et al.  Inverse Compton Origin of the Hard X-Ray and Soft Gamma-Ray Emission from the Galactic Ridge , 2008, 0804.1774.

[25]  G. Helou,et al.  Connecting Far-Infrared and Radio Morphologies of Disk Galaxies: Cosmic-Ray Electron Diffusion After Star Formation Episodes , 2008, 0801.4768.

[26]  G. Fazio,et al.  Galactic structure from the Spacelab infrared telescope. II, Luminosity models of the Milky Way , 1991 .

[27]  Secondary Antiprotons and Propagation of Cosmic Rays in the Galaxy and Heliosphere , 2001, astro-ph/0106567.

[28]  Todd A. Thompson,et al.  The Starburst Contribution to the Extragalactic γ-Ray Background , 2006, astro-ph/0606665.

[29]  Abraham Loeb,et al.  ON THE GeV AND TeV DETECTIONS OF THE STARBURST GALAXIES M82 AND NGC 253 , 2010, 1003.3257.

[30]  George Helou,et al.  Thermal infrared and nonthermal radio: remarkable correlation in disks of galaxies , 1985 .

[31]  Olaf Reimer,et al.  Diffuse Continuum Gamma Rays from the Galaxy , 2000 .

[32]  Production and propagation of cosmic ray positrons and electrons , 1997, astro-ph/9710124.

[33]  D. Thompson,et al.  CONSTRAINTS ON THE COSMIC-RAY DENSITY GRADIENT BEYOND THE SOLAR CIRCLE FROM FERMI γ-RAY OBSERVATIONS OF THE THIRD GALACTIC QUADRANT , 2010, 1011.0816.

[35]  G. Weidenspointner,et al.  Radioactive 26Al from massive stars in the Galaxy , 2006, Nature.