Radio and infrared emission from starburst galaxies

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6062169

Stine, P C

Radio emission was compared to infrared emission for a sample of 58 starburst Markarian galaxies. New radio observations were from the very large array (VLA) at 6 and 20 cm in the B and A configurations. Infrared astronomy satellite (IRAS) data were reanalyzed using ADDSCAN for 25 of the starbursts that were undetected at either 25 or 100 mu in the IRS Point Source Catalog. The IR spectral indices are steeper for alpha (sup 25)(sub 12) and flatter for alpha (sup 60)(sub 25) and alpha (sup 100)(sub 60) when compared to normal galaxies. The IR spectral indices alpha (sup 25)(sub 12) and alpha (sup 100)(sub 60) are anticorrelated, indicating more than one population of dust grains in starbursts. The starbursts have a stronger warm component than normal galaxies. A significant portion of the warm component of the infrared emission is emitted at wavelengths shorter then 60 mu. A very tight correlation between radio and infrared luminosity exists over a factor of 10,000 in 60 mu luminosity density. The bulk of the radio emission is nonthermal. The radio spectral index does not appear to be correlated with the infrared emission. The sizes of the radio emitting regions appear to be larger than the starburst, and the radio spectral indices steepen away from the center. This indicates that the material generating the nonthermal emission leaks out of the starburst region. A three-component model describing the radio emission is discussed. The starburst region contains thermal radio emission from H II regions around hot stars, nonthermal radio emission from discrete supernova remnants, and nonthermal emission from cosmic rays generated by the supernovae. The outer region contains only the nonthermal emission from cosmic rays that have traveled away from the starburst region.

• Research Organization: Pennsylvania State Univ., University Park, PA (USA). Davey Lab.
• OSTI ID: 6062169
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RADIO SOURCES
DATA
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
GALAXIES
INFORMATION
INFRARED RADIATION
LUMINOSITY
MARKARIAN GALAXIES
NUMERICAL DATA
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
RADIOWAVE RADIATION
SUPERNOVA REMNANTS