M94 as a Unique Testbed for Black Hole Mass Estimates and AGN Activity at Low Luminosities

Figure 3

The mosaic-ed F555W (V-band; combination of 5 WFPC2 images taken at two different epochs) image of the NGC4736 nucleus, with intensity contours overlaid (green). The position of the STIS-nucleus is indicated (by the yellow slit) along with the locations of the 2 most luminous and closest to the nucleus hard X-ray sources, X1 and X2, as detected with Chandra (red squares), along with the position of the 15 GHz VLA radio core ([46], orange circle), and those of the two radio compact sources detected by Körding et al. [31] (white circles). The blue and cyan contours correspond to the F330W and F250W observations from Maoz et al. [29]; note the presence of NGC 4736b, ≈ 2.^′′5 to the north of the nucleus. The absolute astrometry is good to within 0.^′′2 (pixel size is 0.^′′05 for F555W, and 0.^′′025 for F250W and F330W).