Constraining the Origin of Local Positrons with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae

Lopez-Coto, Ruben; Casanova, Sabrina; Dingus, B.; Salesa-Greus, F.; Zhou, H.

doi:10.22323/1.312.0011

Title: Constraining the Origin of Local Positrons with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae

Abstract

Cosmic-ray positrons are charged antiparticles that strike Earth's atmosphere isotropically. At energies below several GeV they are produced by cosmic-ray protons interacting with nearby interstellar matter. At higher energies, an unexpected and unexplained excess above the proton-induced background has been detected by several satellites, including PAMELA, AMS-02 and Fermi. Due to energy losses in interstellar magnetic and radiation fields, the highest-energy positrons observed must have originated in our immediate Galactic neighborhood. This excess has been theorized to be originated from nearby astrophysical sources, dark matter, or new modes of cosmic-ray secondary production. Amongst the astrophysical sources, pulsars as Geminga and PSR B0656+14 have been proposed to be contributors to this excess. The HAWC Gamma-Ray Observatory reported the discovery of TeV gamma-ray emission extending several degrees around the positions of Geminga and PSR B0656+14 pulsars. Using the morphological and spectral measurements of these two VHE gamma-ray sources, we determine the diffusion coefficient of electrons escaping them and their contribution to the positron flux measured at Earth. For this assumption of isotropic diffusion, we find that neither of these sources make an appreciable contribution to the locally measured positron flux.

Authors:

Lopez-Coto, Ruben ^[1]; Casanova, Sabrina ^[2]; Dingus, B. ^[3]; Salesa-Greus, F. ^[4]; Zhou, H. ^[3]

Max-Planck-Inst. für Kernphysik, Saupfercheckweg, Heidelberg (Germany)
Max-Planck-Inst. für Kernphysik, Saupfercheckweg, Heidelberg (Germany); Inst. Fizyki Ja˛drowej, Radzikowskiego, Krakow (Poland)
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Inst. Fizyki Ja˛drowej, Radzikowskiego, Krakow (Poland)

Publication Date:: Tue Dec 12 00:00:00 EST 2017

Research Org.:: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:: USDOE Laboratory Directed Research and Development (LDRD) Program

Contributing Org.:: HAWC Collaboration

OSTI Identifier:: 1565877

Report Number(s):: LA-UR-17-27617
Journal ID: 1824-8039

Grant/Contract Number:: 89233218CNA000001

Resource Type:: Accepted Manuscript

Journal Name:: PoS - Proceedings of Science

Additional Journal Information:: Journal Volume: 312; Conference: 7th International Fermi Symposium, Garmisch-Partenkirchen (Germany), 15-20 Oct 2017

Publisher:: SISSA

Country of Publication:: United States

Language:: English

Subject:: 79 ASTRONOMY AND ASTROPHYSICS; Astronomy and Astrophysics

Citation Formats


                    Lopez-Coto, Ruben, Casanova, Sabrina, Dingus, B., Salesa-Greus, F., and Zhou, H. Constraining the Origin of Local Positrons with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae.  United States: N. p., 2017. 
Web.  doi:10.22323/1.312.0011.

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                    Lopez-Coto, Ruben, Casanova, Sabrina, Dingus, B., Salesa-Greus, F., & Zhou, H. Constraining the Origin of Local Positrons with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae.  United States.  https://doi.org/10.22323/1.312.0011

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                    Lopez-Coto, Ruben, Casanova, Sabrina, Dingus, B., Salesa-Greus, F., and Zhou, H. Tue .  
"Constraining the Origin of Local Positrons with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae".  United States.  https://doi.org/10.22323/1.312.0011.  https://www.osti.gov/servlets/purl/1565877.

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@article{osti_1565877,

  title        = {Constraining the Origin of Local Positrons with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae},

  author       = {Lopez-Coto, Ruben and Casanova, Sabrina and Dingus, B. and Salesa-Greus, F. and Zhou, H.},

  abstractNote = {Cosmic-ray positrons are charged antiparticles that strike Earth's atmosphere isotropically. At energies below several GeV they are produced by cosmic-ray protons interacting with nearby interstellar matter. At higher energies, an unexpected and unexplained excess above the proton-induced background has been detected by several satellites, including PAMELA, AMS-02 and Fermi. Due to energy losses in interstellar magnetic and radiation fields, the highest-energy positrons observed must have originated in our immediate Galactic neighborhood. This excess has been theorized to be originated from nearby astrophysical sources, dark matter, or new modes of cosmic-ray secondary production. Amongst the astrophysical sources, pulsars as Geminga and PSR B0656+14 have been proposed to be contributors to this excess. The HAWC Gamma-Ray Observatory reported the discovery of TeV gamma-ray emission extending several degrees around the positions of Geminga and PSR B0656+14 pulsars. Using the morphological and spectral measurements of these two VHE gamma-ray sources, we determine the diffusion coefficient of electrons escaping them and their contribution to the positron flux measured at Earth. For this assumption of isotropic diffusion, we find that neither of these sources make an appreciable contribution to the locally measured positron flux.},

  doi          = {10.22323/1.312.0011},

  journal      = {PoS - Proceedings of Science},

  number       = ,

  volume       = 312,

  place        = {United States},

  year         = {Tue Dec 12 00:00:00 EST 2017},

  month        = {Tue Dec 12 00:00:00 EST 2017}

}

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Works referencing / citing this record:

EDGE: a code to calculate diffusion of cosmic-ray electrons and their gamma-ray emission
conference, August 2018

Lopez-Coto, Ruben; Hahn, Joachim; Hinton, Jim
Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)
DOI: 10.22323/1.301.0735

Constraining the Diffusion Coefficient with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae
preprint, January 2017

Zhou, Hao; López-Coto, Rubén; Greus, Francisco Salesa
arXiv
DOI: 10.48550/arxiv.1709.03620

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Title: Constraining the Origin of Local Positrons with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae

Abstract

Citation Formats

EDGE: a code to calculate diffusion of cosmic-ray electrons and their gamma-ray emission conference, August 2018

Constraining the Diffusion Coefficient with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae preprint, January 2017

EDGE: a code to calculate diffusion of cosmic-ray electrons and their gamma-ray emission
conference, August 2018

Constraining the Diffusion Coefficient with HAWC TeV Gamma-Ray Observations of Two Nearby Pulsar Wind Nebulae
preprint, January 2017