M94 as a Unique Testbed for Black Hole Mass Estimates and AGN Activity at Low Luminosities
Figure 1
Spectral fits to the -STIS spectrum of NGC 4736, based on a 5-pixel extraction aperture, which corresponds to a total emission area of 0.025 arcsec2. Upper panel: The thin continuous line shows the observed data, while the green line shows the best-fit stellar population model obtained by clipping out the hashed emission-line region. Middle panel: The continuum subtracted spectrum, that is, the emission-line component, together with the corresponding spectral fit, that have been shifted by an additive constant to match the initial continuum level, for illustration purposes. The thin continuous lines show the individual Gaussian components (1 per narrow line), the thick grey continuous line represents the broad feature, and the red line is the final fit to the observed spectrum. Lower panel: The residuals after the subtraction of the model fit.
