A nonthermal radio halo surrounding M82

Journal Article · Fri Mar 01 04:00:00 EST 1991 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169764· OSTI ID:5701530

Seaquist, E R; Odegard, N ^[1]

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1. Toronto Univ. (Canada) NASA, Goddard Space Flight Center, Greenbelt, MD (USA)

Radio maps at several frequencies are presented which reveal an extended halo of nonthermal emission surrounding the starburst galaxy M82. The origin of this halo is probably synchrotron radiation from relativistic electrons originally produced in SNR, swept out of the disk by the extensive wind associated with the galaxy. The halo appears to be asymmetrical, with an enhancement occurring about 1 arcmin to the south, and on a larger scale there is excess emission to the north. Possible causes of this effect are addressed. The spectral index measured using data at 6, 20, 49, and 90 cm is about -0.4 + or - 0.1 in the nucleus, steepening to about -1.0 in the halo. A simple model is invoked which involves outward convection of relativistic particles with electron energy losses by inverse Compton scattering against IR photons and adiabatic expansion. 35 refs.

• OSTI ID: 5701530
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 369; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BASIC INTERACTIONS
BEAMS
BREMSSTRAHLUNG
COMPTON EFFECT
COSMIC RADIO SOURCES
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ENERGY RANGE
ERUPTIVE VARIABLE STARS
EXPANSION
GALAXIES
INTERACTIONS
LEPTON BEAMS
MAPS
MATHEMATICAL MODELS
MORPHOLOGY
ORIGIN
PARTICLE BEAMS
RADIATIONS
RADIOWAVE RADIATION
RELATIVISTIC RANGE
SCATTERING
SPECTROSCOPY
STARS
SUPERNOVA REMNANTS
SUPERNOVAE
SYNCHROTRON RADIATION
VARIABLE STARS