dat = read.csv('https://gist.githubusercontent.com/geotheory/10ad6b2051e69213f81ccf2366938cda/raw/485c98381579d74ec581e34c1ebfa80b66b76d69/poly-test.csv')

# polynomial model
pm = lm(vy ~ poly(vx, degree=20, raw=TRUE), data = dat)

newdat = data.frame(vx = 10^seq(4,6,.02))
newdat$vy = predict(pm, newdata = newdat)
#> Warning in predict.lm(pm, newdata = newdat): prediction from a rank-
#> deficient fit may be misleading

plot(dat, log='x', pch=16, cex=.6)
lines(newdat, col='red', lwd=3)