Bibcode
Gonzalez-Serrano, J. I.; Perez-Fournon, I.; Junor, W.; Spencer, R.
Referencia bibliográfica
(Instituto de Astrofisica de Canarias and Comision Interministerial de Ciencia y Tecnologia, Summer School on Evolutionary Phenomena in Galaxies, Puerto de la Cruz, Spain, July 4-15, 1988) Astrophysics and Space Science (ISSN 0004-640X), vol. 157, no. 1-2, July 1989, p. 183-186.
Fecha de publicación:
7
1989
Número de citas
6
Número de citas referidas
6
Descripción
CCD photometry and MERLIN observations of M87 (Virgo A) have been used
to study the variations of the radio to optical spectral index along the
jet. In general, the radio spectrum is flatter than the optical one and
both become steeper with distance from the nucleus. The optical fluxes
of the bright knots lie at or below the extrapolation of the radio
spectrum. These properties can be explained by power-law spectra at low
frequencies that turn down gradually beyond a cut-off frequency. The
location of the local cut-off frequency is estimated by fitting the
measured fluxes to the theoretical spectrum of a truncated power-law
electron energy distribution. The results are interpreted in terms of
models of synchrotron emission from shock waves in extragalactic jets.