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

Journal Article · Tue Jan 20 00:00:00 EST 2015 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/799/1/L10· OSTI ID:22364455

Singal, J.; Jones, E.; Dunlap, H. ^[1]

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1. Physics Department, University of Richmond 28 Westhampton Way, Richmond, VA 23173 (United States)

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)

• OSTI ID: 22364455
• Journal Information: Astrophysical Journal Letters, Vol. 799, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTROPHYSICS
AXIAL RATIO
BRIGHTNESS
COMPARATIVE EVALUATIONS
COSMIC RADIO SOURCES
EMISSIVITY
MAPS
MHZ RANGE
PHOTON EMISSION
STAR MODELS
SURFACES