set terminal postscript eps color enhanced font "Helvetica,16pt" size 8.6cm,6cm 

# common settings
set format y "%4g"
set format x "%2.1f"
# set tics scale 2
set tics nomirror
set format y2 "%2.1f"
set y2r [0:2]
set y2tics 0.5
set ytics 1000

set xlabel "Photoevent Separation {/Symbol t} [ns]"
set ylabel "Two-Photon Coincidences"
set y2label "g^{(2)}({/Symbol t})" rotate by -90

# for fit function
N(x)=a+b*((exp(-abs((x-d)/tc)))**2)
M(x)=a+b*((exp(-abs((x/(10**9))/tc)))**2)

	a=1400
	b=1400
	tc=0.0000000004
	d=-0.000000003817
set fit errorvariables
set xrange [-0.00000000688:-0.00000000052]
	FIT_LIMIT=1.e-15
	FIT_MAXITER=1000
	fit N(x) 'g2sun.txt' using 1:2:(sqrt($2)) via a,b,tc,d

set output "g2sun.eps"
set xrange [-2:2]
set yrange [0:2*a]
set samples 1000
plot 'g2sun.txt' using ($1-d)*10**9:2:(sqrt($2)) w yerrorbars notitle,\
M(x) w l ls -1 notitle