Optical Jets in Radio Galaxies

Latest News

20-05-2008 - Grand opening of the "Optical Jets in Radio Galaxies" Web Site

Project outline

With the advent of large ground base telescopes, we started few years ago a survey with the VLT aimed at finding the optical counterpart pf low radio-power hot-spots. We are also using high resolution imaginig data from VLA and HST, to obtain excellent frequency-sampling spectral energy distribution of hot-spots.

The project addresses the physics of these regions by exploring particle acceleration scenarios under conditions of strong shock and Rayleigh-Taylor instabilities. The major enphasis is being put in determining the presumed fundamental role of magnetic fields in these regions, in particular in promoting/extending the life of very energetic electrons responsible for the observed optical light.

The electron lifetime is strictly related to the values of the magnetic field: the lower the magnetic field strength, the longer electron population can radiate. For this reason, in order to achieve a high detection rate of optical emission from hot-spots, we observed with the VLT a sample of low radio-power hot-spots, i.e. most likely dominated by low magnetic field values. Targets were selected from the 2 Jy sample of radio sources listed in Tadhunter et al. (1993, MNRAS, 263, 999). Each of these sources were visually inspected using high resolution radio images. Finally, 10 hot-spots with radio power about 10⁴¹ - 10⁴² erg/s, that is one order of magnitude lower than that of previously investigate hot-spots in the optical wavelengths, but still sufficiently bright to warrant a detection with the VLT were observed.