suppose I have the following transfer function

T = 1 / ( tau*s + 1)

Where tau is a real number.

There exists a pole at s = -1/tau

Why does that correspond to a frequency w of 1/tau?

isn't 's' the complex number jw ? so the coefficient of j should be the frequency, but then -1/tau is real and does not have an imaginary part..........

Could somone clarify... ?

Thank you