Star Formation in Superthin Galaxies
  Superthin galaxies (STs) are low surface brightness galaxies (LSBs) (central
surface brightness in $B$-band $>$ 23 magarcsec$^{-2}$) with a strikingly high
planar-to-vertical axes ratio of $\sim 10 - 20$ with no bulge component. The
superthin vertical structure of STGs results in significantly lower values of
disc dynamical stability (Jog 1992) and hence higher values of the predicted
SFR compared to face-on LSBs. We systematically study the star formation rate
(SFR) of samples of STGs and LSBs and compare their relative values. Using
GALEX FUV, we estimate the SFR of 212 STGs and 158 LSBs, the median values
being 0.057 $M_\odot /yr$ and 0.223 $M_\odot /yr$ respectively. We next obtain
the SFR from WISE (W3) of 549 STGs and 345 LSBs, with median values of 0.471
$M_\odot /yr$ and 0.17 $M_\odot /yr$ respectively. Finally, from SED fitting of
photometric data in ten bands (FUV, NUV of GALEX, u,g,r,i,z of SDSS \& J, H, Ks
of 2MASS) in MAGPHYS, we find the SFR for a sample of 65 STGs and 103 LSBs to
be 0.357 $M_\odot /yr$ and 0.616 $M_\odot /yr$ respectively. Also, as is
indicated by the median values of number of bursts after $t_{\rm{form}} = 1$
and an exponential star formation time scale parameter $\gamma$ = 0.2
${\rm{Gyr}}^{-1}$, the SFR remains fairly constant over time. Interestingly, in
spite of having low SFR compared to ordinary star-forming galaxies, both
superthins and LSBs populate the star forming blue cloud region in the specific
star formation (sSFR) - stellar mass (M*) plane of galaxies.
