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We present DEIMOS multi-object spectroscopy (MOS) of 22 star-forming dwarfgalaxies located in four gas-rich groups, including six newly-discovereddwarfs. Two of the galaxies are strong tidal dwarf galaxy (TDG) candidatesbased on our luminosity-metallicity relation definition. We model the rotationcurves of these galaxies. Our sample shows low mass-to-light ratios(M/L=0.73$\pm0.39M_\odot/L_\odot$) as expected for young, star-forming dwarfs.One of the galaxies in our sample has an apparently strongly-falling rotationcurve, reaching zero rotational velocity outside the turnover radius of$r_{turn}=1.2r_e$. This may be 1) a polar ring galaxy, with a tilted bar withina face-on disk; 2) a kinematic warp. These scenarios are indistinguishable withour current data due to limitations of slit alignment inherent to MOS-modeobservations. We consider whether TDGs can be detected based on their tidalradius, beyond which tidal stripping removes kinematic tracers such asH$\alpha$ emission. When the tidal radius is less than about twice the turnoverradius, the expected falling rotation curve cannot be reliably measured. Thisis problematic for as much as half of our sample, and indeed more generally,galaxies in groups like these. Further to this, the H$\alpha$ light thatremains must be sufficiently bright to be detected; this is only the case forthree (14%) galaxies in our sample. We conclude that the falling rotationcurves expected of tidal dwarf galaxies are intrinsically difficult to detect.

Kinematics of dwarf galaxies in gas-rich groups, and the survival and detectability of tidal dwarf galaxies