Poster Title: A nursery of young objects: HII regions in the intragroup medium of Stephan's Quintet.
Abstract: Four knots with spectra of vigorous star-forming regions are found in the intra-group medium of the Stephan's Quintet, not attached to any optical tails, more than 50 kpc away from the center of the most probable parent galaxy (NGC 7319). They have M$_B$ ranging from --11.5 to --12.2 mag, colours from B-R = 0.7 to 1.0 mag, radial velocities from 6580--6670 km/s and three of them are supperposed onto the HI tail east of NGC 7319, with a mean radial velocity of 6600 km/s. In addition, they have metallicities of the order of 12+log(O/H) = 8.6 $\pm$ 0.1, which suggests that they were formed from pre-enriched material. We derive a mean age of $4.6 \pm 0.6$ Myr and a mean stellar mass of $(2.0 \pm 0.3) \times 10^5~M_\odot$ for the four objects. The masses, ages, colours, velocities, metallicities and location of the objects suggest that they are HII regions that were formed away from the galaxies. This is possible given that the intragroup medium of the Stephan's quintet contains a significant amount of HI which could be compressed by collisions, increasing its density, and enhancing the star formation efficiency.
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