fig = plt.figure(figsize=(6,4))
ax1 = fig.add_subplot(111)
ax1.set_xlabel(r"$v$ (km/s)", fontsize=16)
ax1.set_ylabel(r"$T_{\rm B}$ (K)", fontsize=16)
v, T1, T2 = np.loadtxt('rosette_CO_spectrum.txt', unpack=True)
vmin, vmax = 5, 21
ax1.set_xlim(vmin, vmax)
ax1.set_ylim(-4, 27)
show = (v > vmin+0.75) & (v < vmax-0.75)
ax1.plot(v[show], T1[show], color='k', lw=2, linestyle='solid', drawstyle='steps', label='CO')
ax1.plot(v[show], T2[show], color='k', lw=2, linestyle='dotted', drawstyle='steps', label=r'$^{13}$CO')
# get integrated intensity
int = (v > 11) & (v < 16)
T1_int = integrate.simps(T1[int],v[int])
T2_int = integrate.simps(T2[int],v[int])
print("Integrated CO emission = {0:5.2f} K km/s".format(T1_int))
print("Integrated 13CO emission = {0:5.2f} K km/s".format(T2_int))
ax1.legend()
fig.tight_layout()
plt.savefig('rosette_CO_spectrum.pdf')