# Sensitivity

The sensitivity of Advanced Virgo is given as function of the gravitational wave frequency in terms of the (amplitude spectral density of the) interferometer output noise, expressed in units of gravitational wave strain. Thus the lower the curve (and hence the lower the noise), the more sensitive the detector is in that frequency range. Advanced Virgo is sensitive in the frequency interval from a few Hertz to several thousands of Hertz (kHz): this is the range of frequencies for the gravitational waves that can be detected. During the years, the sensitivity of Virgo has improved constantly. The plot here shows the projected sensitivity for the fifth observation period, O5, foreseen to start in the year 2026. The final expected sensitivity (black curve) results from the sum of the noises contributed by different sources: the plot lists the more relevant ones for O5. We expect to operate Advanced Virgo in O5 in a dual recycled configuration (ie with both power and signal recycling), with 80 W input laser power, Frequency Dependent Squeezing and partial cancellation of Newtonian Noise; the mirrors suspended at the end of the arms will weigh about 100 kg each!