The NGC 5903 galaxy group is a nearby ( \sim 30 Mpc ) system of \sim 30 members , dominated by the giant ellipticals NGC 5903 and NGC 5898 .
The group contains two unusual structures , a \sim 110 kpc long H i filament crossing NGC 5903 , and a \sim 75 kpc wide diffuse , steep-spectrum radio source of unknown origin which overlaps NGC 5903 and appears to be partly enclosed by the H i filament .
Using a combination of Chandra , XMM-Newton , GMRT and VLA observations , we detect a previously unknown \sim 0.65 keV intra-group medium filling the volume within 145 kpc of NGC 5903 , and find a loop of enhanced X-ray emission extending \sim 35 kpc southwest from the galaxy , enclosing the brightest part of the radio source .
The northern and eastern parts of this X-ray structure are also strongly correlated with the southern parts of the H i filament .
We determine the spectral index of the bright radio emission to be \alpha _ { 150 } ^ { 612 } =1.03 \pm 0.08 , indicating a radiative age > 360 Myr .
We discuss the origin of the correlated radio , X-ray and H i structures , either through an interaction-triggered AGN outburst with enthalpy 1.8 \times 10 ^ { 57 } erg , or via a high-velocity collision between a galaxy and the H i filament .
While neither scenario provides a complete explanation , we find that an AGN outburst is the most likely source of the principal X-ray and radio structures .
However , it is clear that galaxy interactions continue to play an important role in the development of this relatively highly evolved galaxy group .
We also resolve the question of whether the group member galaxy ESO 514-3 hosts a double-lobed radio source , confirming that the source is a superposed background AGN .