We present the results of deep , high-resolution , 5 GHz Expanded Very Large Array ( EVLA ) observations of the nearby , dwarf lenticular galaxy and intermediate mass black hole candidate ( M _ { \mathrm { BH } } \sim 4.5 \times 10 ^ { 5 } M _ { \sun } ) , NGC 404 .
For the first time , radio emission at frequencies above 1.4 GHz has been detected in this galaxy .
We found a modestly resolved source in the NGC 404 nucleus with a total radio luminosity of 7.6 \pm 0.7 \times 10 ^ { 17 } W Hz ^ { -1 } at 5 GHz and a spectral index from 5 to 7.45 GHz of \alpha = - 0.88 \pm 0.30 .
NGC 404 is only the third central intermediate mass black hole candidate detected in the radio regime with subarcsecond resolution .
The position of the radio source is consistent with the optical center of the galaxy and the location of a known , hard X-ray point source ( L _ { \mathrm { X } } \sim 1.2 \times 10 ^ { 37 } erg s ^ { -1 } ) .
The faint radio and X-ray emission could conceivably be produced by an X-ray binary , star formation , a supernova remnant or a low-luminosity AGN powered by an intermediate mass black hole .
In light of our new EVLA observations , we find that the most likely scenario is an accreting intermediate mass black hole , with other explanations incompatible with the observed X-ray and/or radio luminosities or statistically unlikely .