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Title: AXIAL RATIO OF EDGE-ON SPIRAL GALAXIES AS A TEST FOR BRIGHT RADIO HALOS

We use surface brightness contour maps of nearby edge-on spiral galaxies to determine whether extended bright radio halos are common. In particular, we test a recent model of the spatial structure of the diffuse radio continuum by Subrahmanyan and Cowsik which posits that a substantial fraction of the observed high-latitude surface brightness originates from an extended Galactic halo of uniform emissivity. Measurements of the axial ratio of emission contours within a sample of normal spiral galaxies at 1500 MHz and below show no evidence for such a bright, extended radio halo. Either the Galaxy is atypical compared to nearby quiescent spirals or the bulk of the observed high-latitude emission does not originate from this type of extended halo. (letters)
Authors:
; ;  [1] ;  [2]
  1. Physics Department, University of Richmond 28 Westhampton Way, Richmond, VA 23173 (United States)
  2. Code 665, NASA Goddard Space Flight Center Greenbelt, MD 20771 (United States)
Publication Date:
OSTI Identifier:
22364455
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 799; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; AXIAL RATIO; BRIGHTNESS; COMPARATIVE EVALUATIONS; COSMIC RADIO SOURCES; EMISSIVITY; MAPS; MHZ RANGE; PHOTON EMISSION; STAR MODELS; SURFACES