Emission line selected galaxies at $z=0.6-2$ in GOODS South: Stellar
  masses, SFRs, and large scale structure
  We have obtained deep NIR narrow and broad (J and Y) band imaging data of the
GOODS-South field. The narrow band filter is centered at 1060 nm corresponding
to redshifts $z = 0.62, 1.15, 1.85$ for the strong emission lines H$\alpha$,
$[$OIII$]$/H$\beta$ and $[$OII$]$, respectively. From those data we extract a
well defined sample ($M(AB)=24.8$ in the narrow band) of objects with large
emission line equivalent widths in the narrow band. Via SED fits to published
broad band data we identify which of the three lines we have detected and
assign redshifts accordingly. This results in a well defined, strong emission
line selected sample of galaxies down to lower masses than can easily be
obtained with only continuum flux limited selection techniques. We compare the
(SED fitting-derived) main sequence of star-formation (MS) of our sample to
previous works and find that it has a steeper slope than that of samples of
more massive galaxies. We conclude that the MS steepens at lower (below
$M_{\star} = 10^{9.4} M_{\odot}$) galaxy masses. We also show that the SFR at
any redshift is higher in our sample. We attribute this to the targeted
selection of galaxies with large emission line equivalent widths, and conclude
that our sample presumably forms the upper boundary of the MS. We briefly
investigate and outline how samples with accurate redshifts down to those low
stellar masses open a new window to study the formation of large scale
structure in the early universe. In particular we report on the detection of a
young galaxy cluster at $z=1.85$ which features a central massive galaxy which
is the candidate of an early stage cD galaxy, and we identify a likely filament
mapped out by $[$OIII$]$ and $H\beta$ emitting galaxies at $z=1.15$.
