Submillimeter spectral break in Seyfert galaxies

Journal Article · Thu Sep 01 04:00:00 EDT 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/185257· OSTI ID:6684063

Engargiola, G; Harper, D A; Elvis, M; Willner, S P

Observations have been made of four Seyfert 1 galaxies at 155 microns and three at 370 microns. Two of the galaxies were detected at 155 microns, but none was detected at 370 microns. The 155 microns data and the strong upper limits at 370 microns show that the infrared continua decrease sharply beyond 100-155 microns. These observations depict a clear spectral difference between radio-loud and radio-quiet active galactic nuclei. The limits on the 100-370 microns spectral slope are consistent either with synchrotron self-absorption of a nonthermal source or with thermal dust emission similar to that arising from the disks of normal galaxies. The 155 microns flux from NGC 4151 is spatially extended through a radius of at least 48 arcsec, arguing for substantial dust emission at wavelengths greater than 80 microns and an even shorter cutoff wavelength for nonthermal emission from the active nucleus. The spectral breaks implied by our data suggest that the nuclear nonthermal sources must be smaller than about 10 light hours. 32 references.

• Research Organization: Yerkes Observatory, Williams Bay, WI (USA); Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA)
• OSTI ID: 6684063
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 332; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCRETION DISKS
COSMIC DUST
COSMIC RADIO SOURCES
DUSTS
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
ENERGY SPECTRA
GALAXIES
GALAXY NUCLEI
INFRARED RADIATION
LIMITING VALUES
RADIATIONS
SEYFERT GALAXIES
SPECTRA