import numpy as np
import matplotlib.pyplot as plt
from matplotlib.ticker import FormatStrFormatter
%matplotlib inline
nu, flux = np.loadtxt('PILS_spectrum.txt', unpack=True)
fig = plt.figure(figsize=(6,4))
ax = fig.add_subplot(1,1,1)
ax.set_xlabel(r"$\nu$ [GHz]", fontsize=16)
ax.set_ylabel(r"Flux [Jy]", fontsize=16)
ax.plot(nu, flux, color='k', lw=1)
ax.xaxis.set_major_formatter(FormatStrFormatter('%5.1f'))
ax.set_xlim(344.55, 347.44)
ax.set_ylim(-0.07, 1.3)
fig.tight_layout()
plt.savefig('PILS_spectrum.pdf')