2015AJ....149..114P

We present a case study of the tidal interaction between low-mass star-forming galaxies initially found in the Sloan Digital Sky Survey (SDSS) images and further analyzed with SDSS spectroscopy and UV GALEX photometry. With a luminosity of M_r= -17.7 mag and exhibiting a prominent tidal filament, UGC 6741 appears as a scaled down version of massive gas-rich interacting systems and mergers. The stellar disk of the smaller companion, UGC 6741_B, which is three times less massive, has likely already been destroyed. Both galaxies, which are connected by a 15 kpc long stellar bridge, have similar oxygen abundances of 12 +log(O/H): (8.3. Several knots of star-forming regions are identified along the bridge, some with masses exceeding : (10⁷ M_☉. The most compact of them, which are unresolved, may evolve into globular clusters or ultra compact dwarf galaxies. This would be the first time progenitors of such objects are detected in mergers involving dwarf galaxies. UGC 6741 currently has the color and star formation properties of blue compact dwarf galaxies (BCDs). However, analysis of its surface photometry suggests that the galaxy lies within the scaling relations defined by early-type dwarf galaxies (dEs). Thus, UGC 6741 appears as a promising system for studying the possible transformation of BCDs into dEs, possibly through a merger episode. The frequency of such dwarf-dwarf mergers should now be explored.