We present the results from the Very Large Array radio continuum total power and polarized intensity observations of Stephan's Quintet at 1.43 and 4.86 GHz, along with complementary 4.85- and 8.35-GHz Effelsberg observations. Our study shows a large envelope of radio emission encompassing all the member galaxies and hence a large volume of intergalactic matter. Infall of the galaxy NGC 7318B produces a ridge of intergalactic, polarized emission, for which the magnetic field strength has been estimated as 11.0 $\pm$ 2.2 μG, with an ordered component of 2.6 $\pm$ 0.8 $\mu$G. The energy density of the field within the ridge area is of the same order as estimates of the thermal component, implying that the magnetic field has a significant role in the dynamics of the intergalactic matter. We also report that the tidal dwarf galaxy candidate SQ-B possesses a strong and highly anisotropic magnetic field, with a total strength equal to 6.5 $\pm$ 1.9 $\mu$G and an ordered component reaching 3.5 $\pm$ 1.2 $\mu$ G, which is comparable to that found in normal-sized galaxies.
keywords in English:
galaxies: groups: individual: HGC 92 (Stephan's Quintet), galaxies: interactions, galaxies: magnetic fields, intergalactic medium, polarization, radio continuum: galaxies
affiliation:
Wydział Fizyki, Astronomii i Informatyki Stosowanej : Instytut – Obserwatorium Astronomiczne