Supermassive black holes in the Sbc spiral galaxies NGC 3310, NGC 4303 and NGC 4258

Guia Pastorini, Alessandro Marconi, Alessandro Capetti +12

We present new Space Telescope Imaging Spectrograph (STIS) observations of three spiral galaxies, NGC 4303, NGC 3310 and NGC 4258. The bright optical emission lines H$\alpha$ $\lambda$ $6564…