Assessing the feasibility of cosmic-ray acceleration by magnetic turbulence at the galactic center

M. Fatuzzo, Fulvio Melia

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The presence of relativistic particles at the center of our Galaxy is evidenced by the diffuse TeV emission detected from the inner 2° of the Galaxy. Although it is not yet entirely clear whether the origin of the TeV photons is due to hadronic or leptonic interactions, the tight correlation of the intensity distribution with the distribution of molecular gas along the Galactic ridge strongly points to a pionic-decay process involving relativistic protons. In previous work, we concluded that point-source candidates, such as the supermassive black hole Sagittarius A* (identified with the High-Energy Stereoscopic System (HESS) source J1745-290) or the pulsar wind nebulae dispersed along the Galactic plane, could not account for the observed diffuse TeV emission from this region. Motivated by this result, we consider here the feasibility that the cosmic rays populating the Galactic center region are accelerated in situ by magnetic turbulence. Our results indicate that even in a highly conductive environment, this mechanism is efficient enough to energize protons within the intercloud medium to the ≳TeV energies required to produce the HESS emission.

Original languageEnglish (US)
Article number21
JournalAstrophysical Journal
Volume750
Issue number1
DOIs
StatePublished - May 1 2012

Fingerprint

cosmic ray
cosmic rays
turbulence
galaxies
energy
protons
relativistic particles
molecular gases
nebulae
pulsars
point sources
point source
ridges
photons
decay
gas
interactions
distribution
in situ
particle

Keywords

  • cosmic rays
  • diffusion
  • ISM: clouds

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Assessing the feasibility of cosmic-ray acceleration by magnetic turbulence at the galactic center. / Fatuzzo, M.; Melia, Fulvio.

In: Astrophysical Journal, Vol. 750, No. 1, 21, 01.05.2012.

Research output: Contribution to journalArticle

@article{e013bd5c622d49af96b9c07c51d5793a,
title = "Assessing the feasibility of cosmic-ray acceleration by magnetic turbulence at the galactic center",
abstract = "The presence of relativistic particles at the center of our Galaxy is evidenced by the diffuse TeV emission detected from the inner 2° of the Galaxy. Although it is not yet entirely clear whether the origin of the TeV photons is due to hadronic or leptonic interactions, the tight correlation of the intensity distribution with the distribution of molecular gas along the Galactic ridge strongly points to a pionic-decay process involving relativistic protons. In previous work, we concluded that point-source candidates, such as the supermassive black hole Sagittarius A* (identified with the High-Energy Stereoscopic System (HESS) source J1745-290) or the pulsar wind nebulae dispersed along the Galactic plane, could not account for the observed diffuse TeV emission from this region. Motivated by this result, we consider here the feasibility that the cosmic rays populating the Galactic center region are accelerated in situ by magnetic turbulence. Our results indicate that even in a highly conductive environment, this mechanism is efficient enough to energize protons within the intercloud medium to the ≳TeV energies required to produce the HESS emission.",
keywords = "cosmic rays, diffusion, ISM: clouds",
author = "M. Fatuzzo and Fulvio Melia",
year = "2012",
month = "5",
day = "1",
doi = "10.1088/0004-637X/750/1/21",
language = "English (US)",
volume = "750",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - Assessing the feasibility of cosmic-ray acceleration by magnetic turbulence at the galactic center

AU - Fatuzzo, M.

AU - Melia, Fulvio

PY - 2012/5/1

Y1 - 2012/5/1

N2 - The presence of relativistic particles at the center of our Galaxy is evidenced by the diffuse TeV emission detected from the inner 2° of the Galaxy. Although it is not yet entirely clear whether the origin of the TeV photons is due to hadronic or leptonic interactions, the tight correlation of the intensity distribution with the distribution of molecular gas along the Galactic ridge strongly points to a pionic-decay process involving relativistic protons. In previous work, we concluded that point-source candidates, such as the supermassive black hole Sagittarius A* (identified with the High-Energy Stereoscopic System (HESS) source J1745-290) or the pulsar wind nebulae dispersed along the Galactic plane, could not account for the observed diffuse TeV emission from this region. Motivated by this result, we consider here the feasibility that the cosmic rays populating the Galactic center region are accelerated in situ by magnetic turbulence. Our results indicate that even in a highly conductive environment, this mechanism is efficient enough to energize protons within the intercloud medium to the ≳TeV energies required to produce the HESS emission.

AB - The presence of relativistic particles at the center of our Galaxy is evidenced by the diffuse TeV emission detected from the inner 2° of the Galaxy. Although it is not yet entirely clear whether the origin of the TeV photons is due to hadronic or leptonic interactions, the tight correlation of the intensity distribution with the distribution of molecular gas along the Galactic ridge strongly points to a pionic-decay process involving relativistic protons. In previous work, we concluded that point-source candidates, such as the supermassive black hole Sagittarius A* (identified with the High-Energy Stereoscopic System (HESS) source J1745-290) or the pulsar wind nebulae dispersed along the Galactic plane, could not account for the observed diffuse TeV emission from this region. Motivated by this result, we consider here the feasibility that the cosmic rays populating the Galactic center region are accelerated in situ by magnetic turbulence. Our results indicate that even in a highly conductive environment, this mechanism is efficient enough to energize protons within the intercloud medium to the ≳TeV energies required to produce the HESS emission.

KW - cosmic rays

KW - diffusion

KW - ISM: clouds

UR - http://www.scopus.com/inward/record.url?scp=84859762701&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84859762701&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/750/1/21

DO - 10.1088/0004-637X/750/1/21

M3 - Article

VL - 750

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 21

ER -