We discuss the peculiar nature of the nucleus of M94 ( NGC 4736 ) in the context of new measurements of the broad H \alpha emission from HST -STIS observations .
We show that this component is unambiguously associated with the high-resolution X-ray , radio , and variable UV sources detected at the optical nucleus of this galaxy .
These multi-wavelength observations suggest that NGC 4736 is one of the least luminous broad-line ( type 1 ) LINERs , with L _ { bol } = 2.5 \times 10 ^ { 40 } Â erg s ^ { - } 1 .
This LINER galaxy has also possibly the least luminous broad line region known ( L _ { H \alpha } = 2.2 \times 10 ^ { 37 } Â erg s ^ { -1 } ) .
We compare black hole mass estimates of this system to the recently measured \sim 7 \times 10 ^ { 6 } ~ { } M _ { \sun } dynamical black hole mass measurement .
The fundamental plane and M - \sigma ^ { * } relationship roughly agree with the measured black hole mass , while other accretion based estimates ( the M - FWHM ( H \alpha ) relation , empirical correlation of BH mass with high-ionization mid IR emission lines , and the X-ray excess variance ) provide much lower estimates ( \sim 10 ^ { 5 } M _ { \sun } ) .
An energy budget test shows that the AGN in this system may be deficient in ionizing radiation relative to the observed emission-line activity .
This deficiency may result from source variability or the superposition of multiple sources including supernovae .