  It is exceedingly rare to find quiescent low-mass galaxies in the field.
UGC5205 is an example of such a quenched field dwarf
($M_\star\sim3\times10^8M_\odot$). Despite a wealth of cold gas ($M_{\rm
HI}\sim 3.5 \times 10^8 M_\odot$) and GALEX emission that indicates significant
star formation in the past few hundred Myr, there is no detection of H$\alpha$
emission -- star formation in the last $\sim 10$ Myr -- across the face of the
galaxy. Meanwhile, the near equal-mass companion of UGC5205, PGC027864, is
starbursting ($\rm EW_{\rm H\alpha}>1000$ Angstrom). In this work, we present
new Karl G. Jansky Very Large Array (VLA) 21 cm line observations of UGC5205
that demonstrate that the lack of star formation is caused by an absence of HI
in the main body of the galaxy. The HI of UGC5205 is highly disturbed; the bulk
of the HI resides in several kpc-long tails, while the HI of PGC027864 is
dominated by ordered rotation. We model the stellar populations of UGC5205 to
show that, as indicated by the UV-H$\alpha$ emission, the galaxy underwent a
coordinated quenching event $\sim\!100-300$ Myr ago. The asymmetry of outcomes
for UGC5205 and PGC027864 demonstrate that major mergers can both quench and
trigger star formation in dwarfs. However, because the gas remains bound to the
system, we suggest that such mergers only temporarily quench star formation. We
estimate a total quenched time of $\sim 560$ Myr for UGC5205, consistent with
established upper limits on the quenched fraction of a few percent for dwarfs
in the field.
