$U-V$ colors and UV slopes of the galaxies that would be selected as LBGs from the sample of @vandokkum06 (purple histogram); and 3) the distribution of rest-frame UV slopes of a $z\sim3.7$ sample of galaxies from @brammer07 selected with the color criterion $H-K>0.9$ to have prominent Balmer/4000 Å  breaks between the $H$ and $K$ bands (cyan histogram).

[lccc]{} $r_{\rm tot}$ (obs) & 25.3 & 26.1 & 27.8\
$H-K$ (obs) & 0.75 & 1.16 & 1.42\
$V_{\rm tot}$ (rest) & $-$24.2 & $-$23.5 & $-$23.3\
$U-V$ (rest) & 1.26 & 1.64 & 1.90\
$\beta$ (rest) & $-$0.56 & $-$0.36 & 0.07\

The typical very massive galaxy at $3.0 \leq z < 4.0$ (median stellar mass $\langle M_{\rm star}\rangle \sim 3 \times 10^{11}$ M$_{\sun}$) is red and faint in the observer’s optical, with $\langle r_{\rm tot}\rangle=26.1$. Most galaxies (10 out of 14) would be selected as $H-K$ galaxies with $H-K>0.9$ [@brammer07]. Of the four galaxies with $H-K<0.9$, only two galaxies have $H-K$ color significantly smaller than the $H-K$ criterion. This highlights the efficiency of this color technique in selecting galaxies at $z>3$ with prominent breaks in the rest-frame optical, although the fraction of interlopers selected by this color technique remains uncertain.

From 