  It is shown that the gray-body factor for a one-dimensional elongated
Bose-Einstein condensate (BEC) acoustic black hole with one horizon does not
vanish in the low-frequency ($\omega\to 0$) limit. This implies that the analog
Hawking radiation is dominated by the emission of an infinite number
($\frac{1}{\omega}$) of soft phonons in contrast with the case of a
Schwarzschild black hole where the gray-body factor vanishes as $\omega\to 0$
and the spectrum is not dominated by low-energy particles. The infrared
behaviors of certain correlation functions are also discussed.
