HI imaging of dwarf star-forming galaxies: Masses, morphologies and gas
  deficiencies
  The GMRT observations of the HI 21~cm-line emission from 13~nearby dwarf
star-forming galaxies are presented. The ranges of star formation rates and
stellar masses of the sample galaxies are 0.03 -- 1.7~$M_\odot~{\rm yr}^{-1}$
and 0.04 -- 22.3~$\times 10^8~M_\odot$, respectively. The HI channel images,
moment images, global profiles and mass surface density profiles are presented
here. The average value of the peak HI mass surface density is estimated to be
$\sim$2.5~M$_{\odot}$~pc$^{-2}$, which is significantly less compared to that
in massive spiral galaxies. The scaling relations of $(M_{stars} + M_{\rm H\,I}
+ M_{\rm He})$ vs $M_{dyn}$, gas fraction vs $M_B$, $M_{\rm H\,I}$ vs
$M_{stars}$, \ion{H}{i}-to-stellar mass ratio vs $M_{stars}$, and $M_{\rm
H\,I}$ vs $D_{\rm H\,I}$ for the sample galaxies are estimated. These scaling
relations can be used to constraint the key parameters in the galaxy evolution
models. These galaxies are residing in group environment with galaxy density up
to 8~galaxy~Mpc$^{-3}$. A HI mass deficiency (with $DEF_{\rm HI} > 0.3$) is
noticed in majority of galaxies for their optical diameters as compared to
galaxies in field environments. Clear signatures of tidal interactions in these
galaxies could be inferred using the HI images. Isolated HI clouds without
known optical counterparts are seen in the vicinity of several galaxies. HI
emission envelope is found to be having an offset from the optical envelope in
several galaxies. Consistent with the previous studies on galaxy evolution in
group environments, tidal interactions seem to play an important role in
triggering recent star formation.
